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OCEANIC BIRDS
OF SOUTH AMERICA
OCEANIC BIRDS
OF SOUTH AMERICA
A-STUDY OF SPECIES OF THE
RELATED COASTS AND SEAS, INCLUDING
THE AMERICAN QUADRANT OF ANTARCTICA
BASED UPON THE BREWSTER - SANFORD
COLLECTION IN THE AMERICAN MUSEUM
OF NATURAL HISTORY
BY
ROBERT CUSHMAN , MURPHY
ILLUSTRATED FROM PAINTINGS BY FRANCIS L. JAQUES
PHOTOGRAPHS, MAPS, AND OTHER DRAWINGS
Vol. II
THE MACMILLAN COMPANY
THE AMERICAN MUSEUM OF NATURAL HISTORY
NEW YORK
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ILLUSTRATIONS
TEXT FIGURES
PaGe
. Dorsal and ventral aspects of three forms of Gadfly Petrels (Prerodroma), be-
longing to distinct oceanic regions, which appear to comprise a group of
closely related, mutually representative species. 698
. Heads of two species of small Gadfly Petrels inhabiting the Juan Fernandez
Islands. 720
. Dorsal and ventral aspects of six genera of Storm Petrels, co illustrate patterns
and proportions. 727
. Sagittal section through the left narial passage of a Diving Petrel (Pelecanoides
garnotii). 771
Dorsal and ventral aspects of the bill in four species of Diving Petrels, illus-
trating specific distinctions. 782
. Bills of Man-o'-war Bird, Cormorant, and Booby. 794
. South American Boobies: dorsal and ventral aspects of six forms. 828
. Trachea and syrinx of the Blue-footed Booby (Sula nebouxi?). 834
. Feathering of face and gular sac, and cross-section of the maxilla, in five
species of South American Cormorants. 872
. Heads of three forms of ‘Blue-eyed Shags,’’ to show the line of demarcation
between dark and light plumage, and the characteristic size of the
excrescence at the base of the maxilla. 880
. Plumage-patterns among several ages and species of Man-o'-war Birds. 923
. Beaks of two species of Steamer Ducks, to illustrate relative size and the
form of the ungues. 953
. Pattern and relative pigmentation of the nestling down in two species of
Flightless Steamer Ducks. 955
. Wing-patterns of three subspecies of Oyster-catchers, to illustrate a charac-
ter correlated with geographic distribution. 974
. Bills of two species of South American Oyster-catchers. 990
. Head of male Sheath-bill. 1000
. Bill of Kelp Gull, to illustrate the deep gonydeal angle occasionally exhibi-
ted by this species. 1061
. The four-year plumage cycles of large gulls of the northern and southern
hemispheres, respectively. 1066
. Outermost rectrix of the Arctic and Antarctic Terns. 1102
COLORED PLATES (UNNUMBERED)
These plates will be found together in a separate section at the back
of the book.
Fairy Terns and Black Noddies, South Trinidad Island.
Frontispiece
Pediunkers, or Gray Petrels, at the nest burrow, Nightingale Island, Tristan
da Cunha.
Peruvian Pelicans, Ancon, Peru.
Blue-footed Boobies in courtship performance, Lobos de Tierra Island, Peru.
Turkey Vulture in flight.
Piqueros, or Peruvian Boobies, Pescadores Island, Peru.
Vv
vi
Ee US ie ReAtIaIORNES
Guanays, or Peruvian Cormorants, Santa Rosa Island, Peru.
Fuegian Oyster-catchers, Falkland Sound.
Gray Gulls, Ancon, Peru.
Belcher’s Gull (with banded tail) and Kelp Gull, Santa Rosa Island, Peru. The
other birds are Peruvian Boobies.
Red-footed Cormorants and Inca Terns, coast of Peru.
NUMBERED PLATES
These plates will be found together in a separate section at the back
PLaTE of the book.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
Sil
52.
Doe
54.
SDE
56.
ie
58.
Nest burrows of the Pink-footed Shearwater. Nocha Island.
A Shoemaker at the entrance of its burrow. South Georgia.
Kermadec Petrels, light and dark phases. Mas Atierra Island.
Fledgling Peruvian Diving Petrel. Vieja Island.
Falkland Diving Petrel, after excavation of its nest. Kidney Island.
Incubating Caribbean Man-o'-war Birds of both sexes. Pearl Islands.
Red-billed Tropic-bird on its egg. Daphne Island, Galapagos.
Brown Pelicans at the Pearl Islands.
Peruvian Pelicans. Chincha Islands.
Incubating female Ridgway'’s Man-o'-war Bird. Tower Island, Galapagos.
Male and female Blue-footed Boobies, to show the sexual dimorphism in the
eye.
The author interviewing a Blue-footed Booby at El Muerto Island.
Piqueros at the north Chincha and south Guafiape Islands.
Pacific Masked Booby. Coming in to the nest, La Plata Island; the character-
istic ring of guano, San Felix Island.
Male Colombian Booby, showing the gray head which distinguishes it from the
Atlantic race. Pearl Islands.
Brown Booby beside its nest. Bahama Islands.
Red-footed Booby. Adult in white phase, and immature. South Trinidad Is-
land. Nesting adult of the gray phase, Tower Island, Galapagos.
South Georgian Blue-eyed Shags in courtship.
Chicks of the South Georgian Blue-eyed Shag at the ages of one and two days,
and of seven weeks.
Young Guanay, to illustrate the length and robustness of the wing.
Brooding female South Georgian Blue-eyed Shag.
King Shag colony. Bleaker Island, Falklands.
Rock Shag colony. East Island, Falklands.
Guanay colony. Pescadores Island.
Bigiid Cormorants roosting on the wreck of the ‘Leonidas,’ Chincha Islands, and
nesting in the rigging of a hulk at Coquimbo.
Flightless Cormorants. Tagus Cove, Galapagos.
King Shag with a billful of nest material. Bleaker Island, Falklands.
Female and young of the South Trinidad Man-o'-war. Bird.
Ridgway's Man-o'-war Bird, Tower Island, Galapagos.
Soaring above the yacht ‘Nourmahal.’ A courting male, with inflated pouch.
PL DSi RALie Ns vii
PLATE
59.
60.
6l.
62.
63.
64.
65.
66.
67.
68.
69.
70.
ape
1p
Family of Falkland Kelp Geese. Bleaker Island.
Nest of Magellanic Kelp Goose. Thomas Island.
Pair of South Georgian Teals.
Magellanic Flightless Steamer Ducks. Hermite Island.
Sheath-bills at Punta Loyola, Patagonia, and among King Shags and Rock-
hopper Penguins at the Falklands.
Sheath-bills. Bleaker Island, Falklands.
Newly hatched Brown Skua. South Georgia.
Nest and eggs of Chilean Skua. Caroline Island.
Brown Skuas foraging in a glacial stream. South Georgia.
Dolphin Gulls, Brown-hooded Gulls, and Magellanic Penguins. Sea Lion Island,
Falklands.
Kelp Gull on the superstructure of a steamer. Coast of Peru.
Dusky Gulls at Conway Bay, Indefatigable Island, and at Darwin Bay, Tower
Island, Galapagos.
Kelp Gulls following a shoal of fish in the Strait of Magellan.
Laughing Gull. Panama.
Mountain Gull. Pisco Bay.
Gray-hooded Gulls. Pisco Bay.
Swallow-tailed Gulls. Darwin Bay, Tower Island, Galdpagos.
South Georgian Tern, and its single egg.
Inca Tern in its nest crevice. San Gallan Island.
Sooty Tern and Brown Noddy. South Trinidad Island.
Inca Terns at the Chincha Islands.
Pacific Fairy Tern, to illustrate the translucence of the wings. Ducie Island.
Atlantic Fairy Tern and chick. South Trinidad Island.
OCEANIC BIRDS OF SOUTH AMERICA
THE PETRELS
FAMILY PROCELLARIIDAE
THE FULMARS, CAPE PIGEONS, WHALE-BIRDS, GADFLY
PETRELS, SHEARWATERS, ETC.
SUBFAMILY PUFFININAE
| CONTINUED |
SHOEMAKER
Procellaria aequinoctialis
Procellaria aequinoctialis Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 132 (Cape of Good Hope).
Names: White-chinned Petrel or Fulmar; Cape Hen; Night-hawk at the Falklands. Synonyms
of the specific name include fuliginosa, nigra, and conspicillata.
Characters: The largest black petrel (excepting the youthful stage of the Giant Fulmar),
with a sharply contrasting pale bill.
Adults (sexes alike): General color sooty black, the concealed portions of the feathers gray,
producing a certain amount of indistinct mottling (disintegration and fading, furthermore, cause
the feathers to acquire somewhat rusty margins, particularly on the breast); chin usually white
in varying degree, some specimens showing only a minute white spot, with black feathers in front
of it between the rami, as well as caudad; in others the white may cover the entire chin, fore-
throat, and sides of face below the gape, while in the phase described as conspicillata it may also
include a variable bar across the forehead, lores, cheeks, and auriculars. Iris seal-brown, separated
by a narrow whitish ring from the cornea, which is brownish instead of white; bill pale yellowish
or greenish horn-color (sometimes almost white) on the naricorn, latericorn, ramicorn, and the
ungues of both mandibles, bluish black on the culmen, mandibular sulcus, and the very tip of the
maxillary unguis; legs and feet black.
14 males from South Georgia, the South Atlantic, and the coasts of Argentina, Chile, and
Peru: wing, 355-400 (385); tail, 116.3-131.5 (124); exposed culmen, 48.6-55.3 (51.7); tarsus,
60-68.2 (65.6); middle toe and claw, 78.6-83.7 (81.1) mm.
8 females from similar sources: wing, 357-383 (377); tail, 113-134.1 (123.7); exposed culmen,
48-51.6 (50.4); tarsus, 62.2-66.2 (63.8); middle toe and claw, 77-84.3 (80.6) mm.
Length in the flesh of one South Atlantic male and one female, 51.4 and 53 cm.; wing-expanse,
respectively, 136.5 and 134 cm.
It is curious that the downy young of this abundant petrel seems never to have been fully
described. Pagenstecher (1885, 22) states that the protoptyle down is ‘‘coffee-brown.”’ In the
collections studied I have found no specimens younger than fledglings.
The egg is white, fine grained, and of highly variable shape, some examples being short ovate
and others greatly attenuated. In most nests they quickly become brown from mud stains. Average
measurements of 19 eggs taken at Cumberland Bay, South Georgia, on November 28 and 30, 1912,
are 83.5 x 54.6mm. Examples covering the extreme dimensions measure: 90.3 x 54.9, 77.2 x 55.8,
86 x 52.8, 81.1 x 56 mm.
Distribution: Breeding at sub-antarctic and low antarctic islands, such as the Falklands,
South Georgia, the Crozet Islands, Kerguelen, and a number of the sub-antarctic outliers of New
Zealand. Ranges southward to the neighborhood of the antarctic circle in the Pacific to westward
642 OCEANIC BIRDS OF SOUTH AMERICA
of the Antarctic Archipelago, northward to about latitude 30° S. in the open oceans, ten or fifteen
degrees farther in the eastern South Atlantic, casually to the neighborhood of Cape Frio, Brazil,
and regularly in the Humboldt Current to northern Peru.
At South Georgia, where this large black petrel is extraordinarily abundant,
I once asked a Norwegian whaleman why the bird was called ‘Shoemaker.’
He replied, ‘Because he sits in his shop and sings.’’ There is no doubt about
that, for the shrill chattering of the species probably makes up a greater volume
of noise than the voices of any other petrels nesting at this antarctic island.
During the active courtship season, in November, the peculiarly penetrating
cries of the Shoemaker make the night air ring, and sound at a distance like a
chorus of frogs. Kidder (1875, 25) well likens the high trill to the note of a
water-whistle. It possesses that piercing quality which seems to set something
within our ears in motion, so that we continue to hear the vibration for a time
after the bird has actually ceased calling. Nor is the singing of these petrels
confined to the night, for when one walks above the roofs of their homes in the
daytime, footfalls among the tussock hummocks will be echoed by expressions
of protests or interest from below ground. The Shoemakers’ voices, however,
seem to be reserved mostly for the breeding territory for, as Wetmore (1926, 52)
remarks, the silence of these great birds at sea impresses one as uncanny. The
only sound I remember hearing from a Shoemaker over the ocean was the
almost terrifying scream ot a wounded bird which I seized and hauled into my
dory in mid-Atlantic.
The American Museum Collection contains a large series of Shoemakers from
the oceans on both sides of southern South America, and also from the Austral-
asian region. In appearance and dimensions all of these birds prove indistin-
guishable. The extent of white on the chin, in particular, is clearly without
geographic significance. Among sixty specimens from four or five distinct
Oceanic areas, an approximately equal variation in this mark is present in each
group.
For example, Beck’s birds taken off Valparaiso, during November, 1913,
include one specimen with no white whatsoever on the chin, and several others
in which the white represents only a trace made up of half a dozen asymmetri-
cally placed feathers. Other Valparaiso birds, however, have the chin entirely
white, and several taken off Corral, Chile, and off various parts of the Peruvian
coast, show the condition developed still further. The same variation appears
among specimens collected along the Atlantic coast of Patagonia, except that
none of these happens to have a chin without any trace of white. A male taken
at Mar del Plata, Argentina, on October 21, 1914, has the fore-throat as well as
the entire chin white, the area being carried up on to the feathered region
behind the ramus of the mandible. This bird also has a spot made up of a few
white feathers on the lower belly. Another male, captured during the Cleveland
Museum Expedition in latitude 18° 37’ S., longitude 2° 38’ W., on September 8,
1925, has an almost equally extensive white throat-patch, as well as a few
white feathers on the lower belly. The original description of the species
aequinoctialis was based upon the figure of a bird without white on the chin.
SHOEMAKER 643
Our series shows that such examples are still to be found, and that there is no
justification for the several subspecific names that have been applied with
reference to this genetically variable character.
The same variability leads, I have no doubt, to the rarer, spectacled condition
which has received the specific name conspicillata. No two birds of this type
appear to be exactly alike. Our only specimen is one without data in the
Lawrence collection. In this the white spot on the chin is surrounded by black
feathers, just as among many normal examples of aequinoctialis. A more or less
irregular white line crosses the forehead and lores, loops back under the eye,
and turns upward across the auriculars. The nature of this mark, in its general
appearance and asymmetry, makes it seem entirely analogous with the variable
white chin. The measurements of the specimen fit well into those of the
general series.
In latitude 27° S., longitude 39° W., of the South Atlantic, Isaw a Shoemaker
of the conspicillata type mingling with many of the normal birds as they fed
astern of my brig. It was distinguishable in no other way than through the
appearance of its head. Gould (1865, 445) states that birds of the sort are to
be observed off the Falklands and in the neighborhood of Tristan da Cunha,
the latter not being a breeding station for any form of Procellaria. Pelzeln
(1869, 143) records the capture of *‘conspicillata’’ in latitude 31° 40’ S., longitude
12° 41’ W., north of Tristan, on September 11, 1857. The specimen was a male
with a wing-spread of 137 centimeters, exactly that of typical aequinoctialis.
From all of the above it seems certain that the white-headed birds represent
merely a phase that crops out from time to time in the Shoemaker population,
and not a rare or dwindling species, as suggested by Alexander (1922, 261). It
is quite likely, nevertheless, that the white-bridled birds may exist in varying
proportion during successive generations, and altogether possible that they
may be at present less numerous than at some earlier period. Apparent cycles
of albinism, or of other peculiarities in color or pattern, have been observed
among numerous animal populations.
The distribution of the Shoemaker is both antarctic and sub-antarctic, but all
of its known breeding grounds lie not far from the convergence between surface
waters of the two zones. So far as we know, South Georgia is the most heavily
glaciated island at which the species nests. The Falkland Islands, where it has
only recently been found breeding (Bennett, 1926, 314), and such New Zealand
islands as the Antipodes, represent the milder extreme of its breeding range.
The factors controlling the distribution of the bird appear to be both subrle
and inflexible, for it nests neither at the South Orkneys, where burrowing in
the soil would be impossible, nor at Gough Island in the milder latitudes of
the Sub-Antarctic Zone. Although a specimen was obtained at Gough by the
‘Scotia’ expedition, it was shot in the coastal waters of the island and there
was no indication of its being a resident species (Clarke, 1913, 285). Further-
more, although the species is common at sea off South Georgia all the year
round, its flight-range seldom extends into high latitudes of the circumpolar
antarctic seas. Reichenow (1908, 553) and Wilkins (1923, 492) indicate that
644 OCEANIC BIRDS OF SOUTH AMERICA
the Shoemaker is likely to be encountered southward a little beyond 60° S.
with more or less regularity, and during the summer season the birds penetrate
somewhat farther toward the polar circle in the neighborhood of the Antarctic
Archipelago, and in the permanently open waters to westward. Its presence
near the South Shetlands may possibly be influenced more or less by whaling
operations, which have tended to draw southward a considerable variety of
sea birds that belong typically to milder oceanic regions. Everywhere, how-
ever, pack-ice forms a barrier which this species does not pass.
The northward range of the Shoemaker extends well toward the edge of
tropical surface waters. In large numbers the birds are rarely seen north of
about 30° S. latitude, but stragglers have been taken as far as 17° S. in the open
ocean, and more frequently in cool-current regions, such as the neighborhoods
of Cape Frio, Sdo Paulo, Iguapé (von Ihering, 1907, 36) and more southerly
parts of the Brazilian coast. In the Humboldt Current the Shoemaker is to be
found throughout the year up to latitude 6° or 7° S., off northern Peru. I myself
saw a group of five off Pimentel on January 16, 1921, which is the height of the
normal breeding season for the species. Mr. Beck observed others off Eten dur-
ing the same month of another year, and thereafter recorded and collected
examples at every season southward along the coasts of Peru and Chile to Chiloé
Island, along various shores of the Magellanic region, and as far off the continent
as the waters around both islands of the Juan Fernandez group.
The Shoemakers begin to come ashore at South Georgia before the middle
of October. Von den Steinen (1890, 252) saw a large number which had arrived
during a storm on October 15; the birds were moving about among the hum-
mocks of tussock grass as if in search of the entrances to old burrows. They
gave him the impression of being tired, as though from a long flight at sea
although, as pointed out above, many of these petrels apparently remain close
to South Georgia throughout the winter. Pairing seems to take place soon
after landing, and the birds that do not take possession of the remains of burrows
dating from previous years set about to excavate new ones. During my own
field work I found that the greatest concentration of burrows in any colony or
‘““warren’’ was always to be looked for in places where there is a good lee, such
as inland- or eastward-facing slopes of hills. Grass-grown ground with good
drainage, and especially the upper parts of steep banks, are favorite nesting
sites. In such places the holes are sometimes so thickly clustered that there is
little space between them. The burrows are often made directly under hummocks
so that screens of drooping grass more or less cover the entrances. Excavation
begins while much of the ground is still frozen, and lumps and spicules of ice
are to be found in the black vegetal mould thrown out by the birds. Matthews
(1929, 574), whose observations agree closely with my own, watched a Shoe-
maker in the process of digging, at the beginning of November. The bird first
used its beak as a pick, and then scraped the loose earth out of the burrow with
its webbed feet. The entrance to the burrows, after completion, are 25 to 35
centimeters in diameter, but they narrow to less than 20 centimeters at a short
distance inside; in length they range from less than a meter to nearly two. I
SHOEMAKER 645
have found tunnels with two entrances on either side of a tussock hummock
but I suspect that this was due to one bird accidentally sapping into its neigh-
bor’s home. The tunnels may be level or they may slope either up or down; at
the end is a roughly hemispherical nest-chamber, with a horizontal diameter of
about 45 centimeters, large enough to accommodate both adult birds comfort-
ably. It is often situated directly beneath a hummock of grass so that the root-
lets appear through its frozen roof. The nest itself is a raised structure resem-
bling, as Hall (1900, 21) points out, an inverted saucer. This platform is built
of earth, more or less mixed with the wisps of tussock grass and other materials
originally carried in as nest lining, and around its base is a deep gutter, which
is usually half full of water. According to Stead, the Shoemakers build the
nest platforms by standing heel-deep in mud in the middle of the chamber and
raking the soil inward with their bills (Oliver, 1930, 133). The thawing snows
on higher hills cause streamlets and waterfalls to come running and tumbling
down between and over the front doors of the burrows, sometimes flooding them
with icy water.
At Cumberland Bay, South Georgia, I found that many birds were still
excavating homes at the end of November, while neighboring nests contained
slightly incubated eggs. Far more surprising was it to discover both digging
and egg-laying in progress at islands in the Bay of Isles as late as January 2,
when incubation was far advanced in all the mainland colonies I had visited.
The work of excavating is done in short shifts, and during intervals of rest the
mud-smeared bird sits outside the burrow and preens its feathers, frequently
uttering its chattering call. At such times it also utters a lower and harsher note,
pointing the beak upward and causing it to vibrate rapidly, in albatross fashion.
Little is known about the courtship performance of the Shoemaker, and
many of the earlier observations were probably insufficiently critical to be
relied upon. Will (1884, 136) watched single birds, which he took to be females,
being besieged by two or more presumed males which clung about the entrance
to a burrow. Von den Steinen describes ‘‘fighting’’ between two birds, but his
description of the Shoemakers lying flat on the ground, bill to bill, with their
throats inflated and their beaks wide open, suggests a familiar type of courtship
behavior rather than combat. While burrowing is under way, or before the
egg has been laid, pairs of birds sit about more or less in the open air, close to
the entrances of their homes, sunning themselves and facing each other, alter-
nately or simultaneously nibbling with their beaks and uttering their shrill
warbles. Their rapid breathing is indicated by tiny oily bubbles flickering at
the nostrils.
It is never difficult to tell whether or not a Shoemaker burrow is occupied,
for any announcement of a caller at the entrance brings immediate vocal response
from within. Matthews states that if an arm is thrust in as far as the sitting
bird, the latter does not at first bite the outstretched fingers. Rather these are
gently touched by the bird’s bill, with movements similar to the ‘‘fencing”’
performance which the albatrosses and other Procellariiform birds indulge in
as part of their social or connubial behavior. This is followed by a gentle
646 OCEANIC BIRDS OF SOUTH AMERICA
nibbling, and only after the deceived Shoemaker has been seized, and forced
to realize that it is not being greeted by its mate, does it start snapping and
scratching. When pulled out of the burrow, it screams stridently and at the
same time makes a curious grunting sound in its throat. While it is capable
of biting severely, the long, sharp, and flinty claws are even more to be dreaded
than the beak. If freed outside the burrow, the bird shows little disposition
to fly. Rather it squats until it is approached once more, whereupon it stands
up on straight legs, opens its mouth wide, and screeches further protests.
After some minutes it may run off among the avenues of hummocks, or launch
into flight. The Shoemaker walks strongly, with a fully digitigrade gait but,
like the weaker-legged petrels, it rests frequently in the squatting posture.
Several birds which I pursued to see how far they would run, soon attempted
to take refuge in other burrows than their own, from which they were promptly
driven out by the rightful occupants.
In nests without an egg I usually met with two adult birds. Large numbers
of eggs were laid within a space of two or three days following the middle of
November and after this I found only a single incubating bird at home. The
adults alternate in the sitting function, but the régime of change has not been
determined. Practically all eggs taken on November 28 and 30, 1912, were
slightly incubated, with embryos up to 15 millimeters in length. The heat of
the birds causes constant melting of ice from the walls of the nest-chamber, and
therefore the egg becomes thickly plastered with mud within a very short time
after it is laid. It would doubtless become buried altogether in cold semi-fluid
soil, were it not for the fact that the nest is a raised structure, as already de-
scribed. The first young were found by members of the German Expedition at
South Georgia on January 15, and it is probable that incubation requires from
50 to 60 days. On January 30 I saw downy chicks which I judged to be a week
or more old. Throughout February and March the parents still come nightly
to feed the young, as Will determined by noting that holes had been pushed
through a blanket of early winter snow which completely obscured the mouths
of the burrows. Some time in April, apparently, the young are abandoned,
but most of the fledglings do not leave their homes, and find their way toward
the water, until May.
Because of the size and strength of the Shoemaker, adult birds are practically
free from molestation by the skua. I have seen the latter in pursuit of a Shoe-
maker high in air, doubtless endeavoring to make it disgorge, but at any rate
the birds are not in danger of being killed and torn to pieces by the enemy.
For this reason, although primarily nocturnal petrels, they do not hesitate to
show themselves freely by day. Not infrequently I have seen them flying back
and forth between burrow and fiord during the broad daylight, something
which no whale-bird or diving petrel could attempt without being gobbled up
by a skua. Oliver (1930, 133) states that these petrels fight a dog more bravely
than any other, generally coming out of a burrow hanging to its ear and ward-
ing it off successfully in the open. According to Olstad (1930, 6) the Shoemaker
burrows at South Georgia are now used extensively by the introduced rats.
SHOEMAKER 647
On November 26, 1912, I observed vast numbers of Shoemakers among other
petrels on the whaling banks off South Georgia. These probably represented
part of the nesting population at the moment on vacation. During the whole
period of rearing the young, the birds are accustomed to fly about high in air,
and in great flocks, over their colonies morning and evening, sometimes keep-
ing up their ecstatic gyrations Jong after daylight, and beginning again long
before dark. Since their quills are hard and stiff, a loud whistling sound is
produced as the birds scale about in the wind. When flying thus over the
nesting grounds, they often tuck one foot forward among the feathers of the
belly and hold the other under the tail.
During my South Atlantic cruise, I found the Shoemakers both abundant
and singularly conspicuous. Their aggressiveness in pursuit of a bait often pre-
vented me from capturing other species which, from a collector's point of view,
I regarded as distinctly preferable. They would drop among, and scatter, a
group of cantankerous Cape Pigeons, to rob the latter of the prey over which
they had been squabbling, and would, in fact, make place only for such com-
petitors as Giant Fulmars and Wandering Albatrosses. On October 31, 1912,
in latitude 27° S., longitude 39° W., I captured numerous Shoemakers on fish-
hooks. They would dive well below the surface in pursuit of sinking bait, and
after being hooked, would fly high in the air, having to be hauled down like
animated kites. They screamed loudly when finally caught in the hands, though
not at earlier stages of the struggle. The voracious creatures learned nothing
by seeing captives drawn on board the ‘Daisy’ before their eyes; even victims
which had escaped from one hook after being hauled part way in, promptly
snapped up another. That the Shoemaker has a well-developed sense of smell
may be indicated by the fact that lines baited with pork fat were ignored so
long as other lines in use at the same time offered the fresh meat and fat of a
loggerhead turtle.
At sea I sometimes saw large bands of these birds settling on the ocean at
dusk, as though to sleep. They floated high, like gulls. On one such occasion,
a bird I had winged swam so fast that a long pull in the dory was necessary to
overtake it.
All observers agree that the food of the Shoemaker consists chiefly of cepha-
lopods, although crustaceans of various sorts have also been found in stomachs,
and von den Steinen (1890, 254) reports vettebrae of fish. Birds which I took
from the nests always ejected a quantity of oily fluid which was much greener
than that of most South Georgian petrels. The same observation may have
misled Loranchet (1915, 190) into believing that this species eats grass during
the period of incubation.
PARKINSON’S PETREL
Procellaria parkinsoni
Procellaria parkinsoni G. R. Gray, 1862, Ibis, p. 245 (New Zealand).
Names: Black Petrel. In earlier literature this species has been listed under the name aequinoctialis.
Characters: Similar to P. aequinoctialis but smaller and with the entire plumage, including the
648 OCEANIC BIRDS OF SOUTH AMERICA
chin, sooty black. Bill horny or greenish yellow, the culmen, sulci, and usually the tip of the
maxillary unguis, black; legs and feet black.
8 males from New Zealand and neighboring waters: wing, 326-359 (343.4); tail, 93-106
(401.1); exposed culmen, 39.4-43.5 (41.7); tarsus, 49.2-55.3 (52.9); middle toe and claw, 62.3-70
(67.8) mm.
4 females: wing, 336-347 (340.7); tail, 95.9-102.5 (100.6); exposed culmen, 39-41.2 (40.4);
tarsus, 52.6-54.2 (53.5); middle toe and claw, 65.8-71.2 (67.9) mm.
The juvenal plumage is glossy blackish brown, with a ‘‘frosted’’ edging on the feathers of
mantle and back. The bill in this stage is said to be ivory-white.
Distribution: Breeds at Little Barrier Island, off northern New Zealand, and perhaps in the
mountains of North Island. Ranges over the South Pacific from Australia to the Galapagos.
This rather rare New Zealand petrel would be regarded as no more than an
accidental straggler into the South American region except for the fact that its
occurrence is based not upon one but upon three discrete records. The specimens
were collected by Beck during the course of the Galapagos Expedition of the
California Academy of Sciences, as follows: a female north of Chatham Island,
October 14, 1905; a male near Charles Island, May 4, 1906; a male in latitude
2° 40’S., longitude 91° 20’ W. The last locality is some distance directly south-
ward of the Galapagos group (Loomis, 1918, 108).
Parkinson's Petrel has become rare even in its homeland because of the
depredations of hogs, dogs, and cats, added to the toll regularly taken by the
Maoris at Little Barrier Island. Furthermore, as pointed out by Falla (1934,
254), its close resemblance to the Shoemaker, and to Pterodroma carneipes and
P. macroptera, introduces a note of uncertainty into many published sight records.
Judging by the latitudes of both its breeding and its flight ranges, Parkinson's
Petrel is a bird of definitely milder waters than its larger relative, Procellaria
aequinoctialis. Its breeding grounds are all well within the Sub-Tropical Zone,
while those of aequinoctialis are confined entirely to waters far south of the
Sub-Tropical Convergence.
The American Museum Collection contains 12 skins, of which 11 were taken
by the Whitney South Sea Expedition in the New Zealand region during the
months of November, December, and January. Most of these birds either had
large gonads or showed evidences of being engaged in nesting. Plumage wear
produces the same effect as in P. aequinoctialis, namely, a disintegration and
bleaching of the terminal portions of the feathers, giving the black birds an
almost reddish cast, especially on the belly. Most of our specimens were col-
lected between latitudes 34° and 38° S., and between longitudes 176° and 180° W.
Falla says that Parkinson's Petrel is the latest species to breed in the northern
New Zealand area. Cleaning out of old burrows has been observed during
November, and the first eggs during the same month. The reproductive season
may be exceptionally long, for young have been recorded at various dates
between December and April. The down is dark brown. The young leave the
burrows chiefly during the month of May, and many of them become washed
ashore during the gales and fogs of that month and of early June.
The call of this petrel on its nesting ground is described as a whistling note,
which suggests resemblance to that of P. aequinoctialis.
PEDIUNKER 649
PEDIUNKER
Adamastor cinereus
Procellaria cinerea Gmelin, 1789, Syst. Nat., 1, p. 563 (‘‘intra circulum antarcticum"’; 48° S., New Zealand
seas, designated as type locality by Mathews, 1912, p. 123).
Names: Pediunker or Paddyunker is the vernacular name at Tristan da Cunha, and may be
derived from the call or song of this petrel. Other names are Night-hawk, Black-tailed Petrel,
Gray or Brown Petrel. Synonyms of the specific name include pallipes, melanura, typus, adamastor,
gelidus, and haesitata.
Characters: A gray-backed, white-breasted bird, to be distinguished from the Greater and
Pink-footed Shearwaters, and from any of the races of Puffinus kublit, by the dark shade beneath
its wings and tail.
Adults (sexes alike): General color above ash-gray, including the back, scapulars, and upper
tail coverts; long scapulars and wing coverts slightly darker than back; bastard-wing and primary
coverts ash-brown; primaries hoary gray, blackish on the outer webs of the outermost two or
three, paler on the inner webs, the shafts ivory whitish toward the base; secondaries hoary gray,
more or less white basally; tail brownish black, with hoary gray on the outer webs of the feathers,
the shafts basally whitish; pileum and sides of head darker than the back, inclining toward slate-
gray; ventral surface mostly white, but with a grayish wash infringing upon the chin, throat,
and neck in fresh plumage; flanks and crissum tinged with brownish gray; the long tail coverts
ash-brown, with faintly paler edges; axillaries and under wing coverts ash-brown, somewhat
scaled by pale edges. Iris brown; bill generally horn-color, the latericorn varying between pale
greenish yellow and bright yellow, the nasal tubes, culmen, cutting edge, and the broad sulcus of
the mandible, black; inside of mouth fleshy red; legs and toes fleshy gray or fleshy white, darker
on the joints, the outer toe, and outer side of tarsus, the webs yellowish gray with pinkish areas
due to the blood vessels; claws blackish hora-color.
6 males (2 from the South Atlantic, 4 from New Zealand waters): wing, 341-350 (346); tail,
110-124 (115.6); exposed culmen, 45.6-47.7 (47); tarsus, 57.6-63.5 (60.3); middle toe and claw,
72.5-76.5 (74.3) mm.
5 females from New Zealand waters: wing, 340-355 (347); tail, 114-118 (116.2); exposed
culmen, 45-49.4 (46.6); tarsus, 57.6-61 (59.2); middle toe and claw, 72-75.5 (73.5) mm.
A well-grown chick has a nearly bare face and throat, but is covered elsewhere with plumbeous
gray down which is slightly lighter, shorter, and denser on the ventral surface than on the head
and back. The entire integument of the bill, with the exception of the hard and corneous ungues,
appears to have been soft in life.
An egg from Macquarie Island is ovoid, white, and measures 71 x 51.5 mm. (Oliver, 1932, 129);
the average measurements of 7 eggs from the same locality are 70.6 x 51.4 mm. (Mathews, 1932, 30).
Eggs recorded from Tristan da Cunha have apparently been misidentified (vide infra).
Distribution: A species of the Sub-Antarctic Zone of surface water, breeding at Gough Island and
Tristan da Cunha, Kerguelen, Macquarie, and Antipodes Islands; ranging over the southern oceans
between about 25° and 55° south latitudes, and regularly northward in the Humboldt Current
to the coast of Peru; recorded as a straggler northward to California.
My first experience with the far-famed Pediunker came in the South Atlantic
on November 4, 1912, in latitude 32° 28’ S., longitude 45° 42’ W., which is due
east of the coast of Uruguay. Examples of this petrel suddenly joined the brig
‘Daisy’ and followed in our wake, together with at least twelve other species,
which included Wandering, Black-browed, Yellow-nosed, and Sooty Alba-
trosses, Giant Fulmar, Cape Pigeon, Blue Petrel (Halobaena), Manx Shearwater,
Shoemaker, Atlantic Petrel, and Wilson's and Black-bellied Storm Petrels
(Murphy, 1914, 318). All of these sea birds were in pursuit of turtle meat which
I trailed from the stern. Whenever the vessel paused in her course for an instant,
650 OCEANIC BIRDS OF SOUTH AMERICA
owing to the rolling seas, there would be a tremendous hurly-burly of birds
battling over the treacherous baits. Although a number of species were thus
captured on hooks or bent nails, I did not succeed in circumventing a Pediunker,
either on this or on subsequent days of angling.
The Pediunkers continued to follow the ‘Daisy’ thereafter, day by day until
November 15 when, in latitude 43° 18’ S., longitude 41° 10’ W., they abruptly
left us. We saw, naturally, no sign of the species during the summer at South
Georgia, but on the homeward voyage large numbers appeared again on March
17, at a point close to latitude 50° S., after which they accompanied us north-
ward to latitude 43° 20’S. The only specimen I succeeded in collecting during
the voyage was a male, in company with Cape Pigeons and Atlantic Petrels
(Prerodroma incerta), shot from a lowered dory on November 9, 1912, in latitude
36° 46’ S., longitude 46° 29’ W.
In addition to the specimen just referred to, the American Museum has a
South Atlantic bird taken in latitude 40° S., longitude 3° 16’ E., during the
voyage of the ‘Southern Cross,’ the old Lawrence skin from Monterey, Cali-
fornia, and an excellent series from Antipodes Island and from neighboring
parts of the western South Pacific. In the Berlin Museum and elsewhere I have
also examined specimens from the Indian Ocean. All of these are alike in
appearance, and more than ordinarily so in all dimensions. The careful color
notes on Beck's New Zealand birds, obtained during the Whitney South Sea
Expedition, indicate furthermore that no adequate basis has yet been pointed
out for distinguishing two or more subspecies of this petrel upon criteria of
bill coloration.
As already suggested, the Pediunker belongs to milder latitudes of the west-
wind zone, stopping short toward the convergence with antarctic surface water.
The southernmost Atlantic record is perhaps that of a single example reported
by Vanh6ffen (1901, 310) not far north of Bouvet Island on November 19. The
only nesting ground that lies on or close to the polar front seems to be Kerguelen,
in the Indian Ocean; the species has not succeeded in making the next leap to
Heard Island, which is short in distance but profound in zodgeographic
significance.
The range of the Pediunker extends farther northward wherever cool currents
affect the continental littoral than it does in mid-ocean. This is particularly
true in the Humboldt Current, and also along the west coast of South Africa,
where Alexander (1922, 261) saw great flocks not far from the shore on March
30, 1920. Even in the western South Atlantic, Alexander reports sighting many
of these birds off the coast of Rio Grande do Sul, Brazil, on May 5, 1921, and
Paessler (1909, 101) met with single examples in May as far north as latitude
24° S., longitude 45° W., a point at the edge of the continental shelf, just south
of Rio de Janeiro and east of Santos. The correspondence between the dates of
Paessler’s and Alexander's observations is interesting, and the appearance of
this species close to Cape Frio is entirely in accordance with the principles of
sea-bird distribution in the South Atlantic, as already pointed out in the section
dealing with the circumnavigation of the continent. The most northerly of all
PEDIUNKER 651
Atlantic records is based upon a single example procured by the Scottish Na-
tional Antarctic Expedition near the island of Ascension. This statement is
made, at least, by Godman (1908, 158), although the specimen does not seem
to be mentioned in the ‘Scotia’ reports.
Turning again to the southern or colder edge of the Pediunker’s range, we
have more data from the Pacific than from the Atlantic. Gain (1914, 129) saw
a large number in latitude 55° S., to westward of Cape Horn, where the ocean
is ice-free and where the Antarctic Convergence turns well southward of its
mean latitudinal position. In longitude 107° 15’ W., on January 26, 1910,
several flew near the French south polar vessel ‘Pourquoi Pas?’ as far southward
as latitude 60° S. Furthermore, Buller (1893, 184) was a passenger on a vessel
followed by a flock of these petrels in the South Pacific during a nine-day portion
of a voyage, which brought the ship within sight of the Diego Ramirez Islands,
south of Cape Horn, on March 16. On March 14, in latitude 56° 52’S., Buller
found the Pediunker to be the commonest of all sea birds. Toward the end of
each day, in this part of the cruise, there would be hundreds about the vessel.
On some days they remained well astern, and again they would fly across the
ship. Their numbers diminished rapidly as the South American continent was
approached, the last examples being observed in latitude 56° 52’ S., longitude
82° 10’ W., a day's sail west of Cape Horn.
These observations call attention to a fact which Buller has specifically
stated, namely, that the Pediunker is to a peculiar degree a strictly pelagic
petrel when absent from its nesting grounds, and is not given to the custom of
entering bays and channels or even to skirting continental shores in the manner
of so many of the Procellariiformes. Giglioli refers to these birds in the Gulf
of Pefias (Godman, 19C8, 158) but, in general, they have rarely been seen either
from shore or from a ship within sight of shore.
This leads directly to an error that has been perpetuated in the literature
ever since the date of publication of the Zodlogy of the ‘Beagle.’ It has to do
with Darwin's alleged note on the Pediunker as he is supposed to have observed
it in the channels behind Chiloé Island, and elsewhere along the southern coast
of South America. The passage is quoted in full in the biography of the Sooty
Shearwater (Puffinus griseus) where, in fact, it belongs. The mistake is due to
a confusion of names which came about as follows:
Gould (1841, 137) quotes Darwin's notes on a species of shearwater which
he lists under the name Puffinus cinereus. The entire context shows beyond doubt
that the species referred to was not the Gray Petrel at all, but the Sooty Shear-
water. Darwin writes for example, ‘‘I obtained specimens from Tierra del
Fuego, Chiloé, the mouth of the Plata, and Callao Bay on the coast of Peru.
It is likewise known to be common in the northern hernisphere.’’ Later in the
same paragraph he lists flesh colors which agree with those of the Sooty Shear-
water, but not with Adamastor. If further proof were needed, one might call
attention to the fact that in 1837, four years before the publication of Part III
of the Zodlogy of the ‘Beagle,’ Gould had listed the Sooty Shearwater in his
“Birds of Europe’’ V, Plate 444, Figure 2, under the name Puwffinus cinereus.
652 OCEANIC BIRDS OF SOUTH AMERICA
Unfortunately, Darwin's notes relating to Puffinus griseus have many times
since been quoted in accounts of Adamastor cinereus. The facts have already been
pointed out by Mathews (1912, 123), who says that the quotation in Godman’s
monograph ‘‘undoubtedly refers to Puffinus griseus Gmelin, as can at once be
recognized by one familiar with these birds in the Southern-hemisphere."’ One
of the latest examples of this mistaken use of the data is in Bent’s life histories
of North American petrels (1922, 105).
Among the whalemen on the brig ‘Daisy,’ the Pediunker, or Night-hawk
as they called it, had a special reputation for being good eating. Hutton (1865,
285) reports that a shipwrecked crew at Kerguelen subsisted largely upon these
birds. In order to save themselves useless digging, the sailors would hold a
living Night-hawk at the mouth of a burrow, teasing it until it cried out. If
another bird was inside, the call would be at once answered, and the men
could begin to tear up the ground with a certainty of reward. Hutton adds that
at Kerguelen the species is almost exclusively nocturnal during the breeding
season, and Carmichael (1818, 497) reports that at Tristan da Cunha, this
petrel, like the Broad-billed Prion, never appears on the wing until after sunset.
Both may then be caught in great numbers merely through kindling a large
fire. Attracted by the light, the petrels approach and flutter around it like so
many moths, many of them becoming dazzled by the glare, and dropping into
the flames.
According to my own field observations, the Pediunkers were always dis-
tinguishable at sea by their style of flight from all other petrels of similar size.
Giglioli has also said that they can be recognized afar by their ‘dipping flight,’
which Hall compares to the wheeling motions of an albatross (Godman, 1908,
158). All day long they would scurry back and forth over the ocean in the
wake of the ‘Daisy,’ gliding a good part of the time as most shearwaters do;
but when they beat their wings, it was with a peculiarly rapid, almost duck-
like motion. Their movements were very graceful as they crossed and recrossed
one another's courses. Toward nightfall we sometimes passed large bands of
them resting on the water.
Alexander (1922, 261) watched flocks of Pediunkers feeding upon shoals of
small fish. The birds were flying low over the water, sometimes rising and
circling, and again shooting down diagonally to plunge beneath the surface.
This bird is by far the best diver of all the sea-going Petrels. It seems even fond of it, and often
remains under water for several minutes, when it comes up again shaking the water off its feathers
. Sometimes I have seen it, as it flies past, poise itself for a moment in the air (and hence
perhaps its name) [referring to the name haesitata] at a height of about twenty or twenty-five feet
above the sea, and, shutting its wings, take a header into the water. It dives with its wings open,
and uses them under water much in the same manner as when flying (Hutton, 1865, 285).
Within our region, the Pediunker nests at the islands of the Tristan group
and at Gough Island. Alvarez (1933, 7) alleges that it breeds also on islands
just off the coast of Uruguay, close to the Gulf of La Plata. While this seems
utterly improbable, the matter is at least worth investigation because of the fre-
quently reported abundance of the bird in near-by parts of the South Atlantic.
PEDIUNKER 653
At Tristan, the Pediunker, long valued as food by the inhabitants, was
equally long of unsatisfactory identity to the scientific world. Certain writers
have applied the name tentatively to the Greater Shearwater (Puffinus gravis), as
well as to other petrels. Keytel, however, obtained specimens and eggs at
Tristan in 1908, which were named by the residents and which are now pre-
served in the South African Museum; and Mathews (1932, 30) has examined
skins, which were labeled with the name ‘‘Padiyunker,’’ from both Inaccessible
and Tristan Islands. Mathews also lists eggs, said to have been taken from
burrows on the mountainside on April 6 and 26, but the measurements of these
are so large that they must pertain to some other species. The average dimen-
sions of the six listed by Mathews are 83 x 56 millimeters, or more than 12
millimeters longer than the average for eggs of Adamastor.
According to Barrow (1910, 275), the Pediunker returns to Tristan to lay
during May and June. The date, like the April one suggested above, would
seem to be the wrong season. Wilkins (1923, 508) obtained a male and female
from separate burrows at an altitude of 550 meters on Gough Island, between
May 28 and June 1. However, he calls special attention to the fact that many
of the local petrels seem to occupy their burrows during other times of year
than the breeding season. At the three islands of the Tristan group there
are, nevertheless, many bits of evidence to suggest that the nesting season
may be irregular, or at least extremely protracted, for a number of the resident
sea birds.
Hutton reports that at Kerguelen Island the Pediunkers return from sea
during September, burrow in wet, peaty earth, and in their nest-chamber con-
struct a mound or cone upon which the egg is laid. The architectural plan
sounds exactly like that of the Shoemaker’s burrow, as described in another
biography.
Moult of the wing and tail quills evidently begins before the young are
abandoned, as indicated by the state of plumage of Pediunkers collected at
and around Antipodes Island during February.
Falla has found lenses and beaks of cephalopods in stomachs of this species
(Oliver, 1931, 30). The birds have also been observed catching fish.
PINK-FOOTED SHEARWATER
Puffinus creatopus
Puffinus creatopus Coues, 1864, Proc. Acad. Nat. Sci. Phila., p. 131 (San Nicolas Island, California).
Names: Cooper's, Coues’s, or Red-footed Shearwater. On the west coast of South America
the common name is ‘'Fardela Blanca,’’ which distinguishes it from the ‘‘Fardela Negra’’ or Sooty
Shearwater. The only true synonym of the specific name seems to be melanoleucus.
Characters: A brown and white shearwater, with a high degree of variation in the markings
of the ventral surface, some specimens being entirely white from chin to crissum, while others are
so heavily freckled and barred as to appear gray-breasted; the lining of the wing likewise varies,
in accordance with the general pigmentation, between nearly all white and prevailingly gray.
The species is closely related to the northern-hemisphere races of Puffinus kuhlit, which nest within
the Mediterranean and at eastern Atlantic islands such as the Azores, Madeira, the Canaries, and
Cape Verdes.
654 OCEANIC BIRDS OF SOUTH AMERICA
Adults (sexes alike): General color of dorsal surface clear brown (slightly grayer than the
mummy brown of Ridgway), lighter edgings to the feathers being inconspicuous except as a result
of abrasion and fading; scapulars, and quills of wing and tail, blackish brown, perceptibly paler
upon the concealed webs of the feathers; wing coverts like the back, the greater series narrowly
fringed with whitish; pileum, hind neck, and sides of neck slightly darker than the back; region
in front of and below eye slightly mottled with whitish; cheeks and sides of neck variably mottled,
such mottling continuing in the form of wavy bars, or irregular freckles, to the gray sides of the
upper breast, which extend ventrad to a greater or less degree toward the mid-line; ventral surface
prevailingly white, the sides of the body variably freckled with ashy brown which, as noted,
sometimes extends clear across the breast and belly; a patch of slaty brown feathers over the thighs;
under tail coverts grayish brown, with a variable amount of white mottling; under wing coverts
white, mottled with dusky black spots on the centers of the feathers, the relative amount of white
or dark varying according to the general type of plumage pigmentation. Iris brown; culmen and
margins of the bill brownish black, the remainder light yellowish flesh color; legs and feet light
flesh color, the outer toe and outer side of tarsus brownish, and the claws whitish with brown tips.
22 males from the west coast of South and North America, and from Juan Fernandez: wing,
321-342 (331); tail, 106.8-116.5 (111.7); exposed culmen, 40.3-46.5 (42.9); tarsus, 52.5-56.3 (54.4);
middle toe and claw, 62.9-70.3 (67.7) mm.
16 females: wing, 322-340 (330); tail, 107-118.5 (112.3); exposed culmen, 39.9-43.2 (41.3);
tarsus, 50.4-56.3 (54); middle toe and claw, 64.3-72 (67) mm.
A point of notable difference between Puffinus creatopus and the shearwaters of the kuhlit group
is that the sexes of the former appear to be of equal size, while among all the races of kwhlii males
are consistently larger than females.
Nestlings taken at Mas Atierra Island on January 31 and February 9 had not long been out of
the egg. They are clad in protoptyle down of Quaker drab or almost purplish gray color dorsally,
the same hue continuing around the neck and appearing in a patch on the lower belly. The re-
mainder of the ventral surface is dirty white, and the face and throat are covered with fine and
short down, instead of being bare. In life the bill was grayish blue and the feet flesh color.
Eggs taken at Mas Atierra on December 15 and January 19 include two normal and one im-
perfect or undersized examples. They are white, except for earth-stains, and have a finely pitted
surface, and a rather elongate shape. Two measure 76.1 x 48.6, and 70.1 x 45.2 mm. The dimen-
sions of the ‘‘runt’’ are 58.4 x 42.4 mm.
Distribution: Confined to the eastern Pacific Ocean of both northern and southern hemispheres.
Breeding at Mas Atierra and Santa Clara Islands of the Juan Fernandez group, and at Mocha Island
(latitude 38° 25’ S.) off the coast of Chile; ranging northward during migration to the coasts of
California, Washington, and Alaska.
This petrel was described in 1864 from a single specimen taken off the Cali-
fornia coast, presumably not on but near San Nicolas Island. Its point of
origin was then unknown, for it was not until a decade later that it was found
breeding at Juan Fernandez. During recent years, it has been learned that the
Pink-footed Shearwater is a common bird from the vicinity of Chiloé Island,
Chile, all the way northward to the coast of southern Alaska.
The species is an eastern Pacific representative of an Old-World shearwater
(Puffinus kublit), which has races in the Atlantic-Mediterranean region and
perhaps in the Indian Ocean. The alleged presence of a resident subspecies at
Kerguelen Island suggests at least a somewhat remote connection between the
present-day ranges of all these related forms. Puffinus leucomelas, of the western
Pacific, is also a relative, though a more distant one. Allin all, Puffinus creatopus
may be regarded as extraordinarily isolated from its nearest of kin, and cor-
related with this fact is its marked specific distinctness, even though it is cer-
PINK-FOOTED SHEARWATER 655
tainly to be considered a member of the same Formenkreis as Puffinus kublii
(Murphy, 1924, 250).
The American Museum possesses a large series of Pink-footed Shearwaters
obtained during the Brewster-Sanford Expedition, as well as numerous speci-
mens from other sources. Among the latter are birds collected by D. S. Bullock
at Mocha Island, Chile, which is a nesting station, during November, 1932;
specimens from Penco, Chile, collected by Carlos S. Reed during December,
1903, and November, 1904; and birds from Monterey, and elsewhere along the
California coast, collected by Beck and others during the months of June, July,
September, October, and November.
On the west coast of South America this shearwater has been observed by
Beck and myself, or by other members of American Museum expeditions, at
many places between La Plata Island, Ecuador, and the Bay of Corral in Chile.
I saw examples off La Plata on September 5, 1919, and offshore from the Gulf of
Guayaquil in January, 1925. Additional dates and localities, taken from Beck's
journal or mine, are as follows: off the Bay of Ferrol, Peru, December 31; near
Mazorca Island, June 14; Pisco Bay, June 27; Mollendo, January 12; Valparaiso,
Chile, many dates between November and March; Corral, many dates between
September 17 and March 28. Examples taken by Beck between Valparaiso and
Juan Fernandez during November and December, 1913, and on or around the
latter islands in January and February, 1914, were mostly in breeding condition.
The incipience of this annual rhythm is shown by enlargement of the gonads
among California specimens collected during September.
As Loomis (1926, 110) has pointed out in connection with California birds,
the American Museum examples of the Pink-footed Shearwater from Chile and
Peru show a wide range of pigmentation between the purely white-breasted
and those with heavily speckled or barred ventral surfaces. Examples repre-
senting the extremes are highly different in appearance, for the darkest would
scarcely be thought of in life as having white breasts or wing-linings. Rather
both of these areas would appear as gray. Such extremes, however, are con-
nected by every intermediate stage.
Birds of this species have been taken in the northern hemisphere during
nearly every month of the year, and Loomis has made a detailed study of the
plumage characters, including the moult, which seems to be protracted during
the long migration of this species into the North Pacific. In South America
the height of the quill-renewal period comes in midwinter, well after the end
of the breeding season. In a specimen taken off Cerro Azul, Peru, on July 4,
1913, the two outermost primaries are still in the sheath, and the wing-length
of the bird is less than 300 millimeters.
Off the west coast of the United States, the Pink-footed Shearwaters mingle
with the Sooty Shearwaters and other visiting species, and are often numerous
for 75 kilometers or more out to sea. Bent (1922, 64) remarks that their gen-
eral appearance and behavior closely resemble those of the familiar Cory’s Shear-
water (Puffinus kublii borealis), of similar latitudes on the Atlantic coast. Dr.
Cooper, who captured the first known specimen of creatopus, found the species
656 OCEANIC BIRDS OF SOUTH AMERICA
abundant and approachable about San Nicolas Island, where the water is shal-
low and where small fish are numerous. Here the birds congregated around
shoals of fry, diving for a short distance in pursuit, and often resting on the
water, swimming buoyantly but not rapidly. This species is an easier and more
graceful flier than Puffinus griseus, making fewer wing strokes, at least when
the breeze is light. The Pink-foots begin to be common on the California coast
about the end of May, which corresponds well with what we know about the
nesting season and the departure of the birds from their breeding giounds in the
eastern South Pacific. However, Beck (1910, 65) saw eight at Point Pinos,
California, on February 27, 1907, an early record for the northward migration.
Most of them go southward again before the end of November.
At Mas Atierra Island, according to Lénnberg (1921, 11), this shearwater
nests high up among the forests, occasionally below tree line but chiefly above
an altitude of 200 meters. It burrows horizontally into sloping ground, some-
times to a length of 2 meters; little or no lining is added to the nest-chamber.
Its eggs have been found during a relatively long season, namely from mid-
December to the end of March. Reed (1874, 83), who writes of this species
under the incorrect name ‘'Thalassoeca glacialoides,’ does not give the date of
his visit to Juan Fernandez, but states that he was directed to the burrows by
peculiar growling barks proceeding from the earth and, upon digging to a depth
of 2 meters, he found pairs of the birds in each of six burrows.
Beck's account of the nesting of this species shows that it occupies a much
wider altitudinal zone than stated by Lonnberg, and that growing vegetation
is not a necessary part of the chosen site. He found the burrows to be distributed
from near the shore of Mas Atierra up into the fern growth at an altitude of
500 meters or thereabouts. Most of the nests were close to the tops of successive
ridges, and some of them were nearly 2 kilometers from the water. Beck's
notes made at Mas Atierra, December 12, 1913, state that when he was out alone
on an all-day hike, he found many burrows of Pink-footed Shearwaters, most
of which penetrated so deeply into the steep hillsides that he concluded a pick
and shovel would be necessary for reaching the nest-chambers. He managed,
however, to trace one tunnel, which ran parallel to the surface of the ground,
and found, about 2 meters from the entrance, a pair of adult birds. These made
absolutely no sound until he had dug well in toward their nest. In some in-
stances a cave-like hollow served as a sort of vestibule for three or four burrows.
In front of many of the holes there was more or less excrement, while the
tunnels and nest-chambers were entirely clean.
Beck’s original notes, as quoted by Bent (1922, 62), are as follows:
On December 12, 1913, I started out from the settlement on Masatierra Island, of the Juan
Fernandez group (which lies about 400 miles to the westward of Valparaiso, Chile), to find the
nests of the pink-footed shearwater. About four miles from the village many holes were found,
but nearly all were too deep and long to be opened without pick or shovel. One hole 6 feet long
was opened and a pair of birds was found at the end. Burrows were found from near shore up into
the ferns at 1,500 feet elevation. On the 15th I went again to the colony with a man to dig for me.
One burrow was followed for 10 feet. It then branched for the third time and went too deep to
follow. Nearly all the burrows were 6 feet or more in length; sometimes a little grass was found
PINK-FOOTED SHEARWATER 657
in the nest, but usually only bare earth in the enlarged end of the burrow. Three eggs only were
taken, alchough a number of holes were opened. On the 31st of January we tried the colony again
and found a few birds on eggs nearly ready to hatch. In two holes examined cold eggs were found
containing young birds alive, though barely able to move. One young bird 3 days old was found
in another burrow. Several single adult birds of both sexes were taken from holes and these on
dissection showed small sexual organs. Some holes that showed fresh soil about them were opened,
but no birds were found in them. On February 7th several rotten and a couple of fresh eggs were
found where they had been scratched out of holes, and many holes showed signs of digging.
On the 19th of January, 1914, I visited Santa Clara Island 10 miles off Masatierra and found
colonies of birds nesting in the soft ground on top of the island. Some of the burrows here were
just below the grass roots and easily opened while others ran deep down. Nearly all the nests
were nicely lined with foxtail straws and an occasional burrow also had a lining. Most of the eggs
were well advanced in incubation and in one nest I found a bird sitting on two eggs. One of these
proved however to be rotten and was probably a last year's egg. The pink-footed shearwater
when disturbed on its egg becomes decidedly pugnacious picking wildly at any object and fre-
quently at a single blow will break its egg before it can be removed from the nest. The birds about
the island in the daytime spend most of their time sitting on the water in flocks, differing in this
respect from their neighbors, the neglected petrels, which nest along the cliffs, and spend their
daylight hours in swinging singly about over the ocean.
In the waters around Mas Atierra, Beck found the Pink-footed Shearwater
to be by far the commonest of local sea birds, sometimes present in great flocks.
Close to Mas Afuera, during late December, only a few were noted, although
numbers of the two resident species of Pterodroma were about over the ocean.
Two kilometers, more or less, off Mas Atierra, the Pink-footed Shearwaters
were accustomed to settle on the water in a “‘raft’’ in order to cleanse their
feathers of the mud and stain of the burrows.
Beck was unable to land upon the outer island, Mas Afuera. Lonnberg,
however, infers that the Pink-footed Shearwater does not nest there. He says,
furthermore, that neither this species nor any other petrel approaches this
island during the day, perhaps because of the presence of their enemy, the
“Blindado”’ (Buteo erythronotus exsul). This hawk is a native only of Mas Afuera,
but examples occasionally fly across the water to Mas Atierra, where they re-
main a few days before returning to their own island. Several Pink-footed
Shearwaters taken out of their burrows on Mas Atierra, and tossed into the air,
were captured by these hawks before they had time to escape to the sea.
If further investigation shows that Puffinus creatopus does not reside at Mas
Afuera, the case will furnish an interesting parallel to the distribution of certain
other petrels in the Juan Fernandez group, for example, the smaller representa-
tives of the genus Pterodroma, of which one species occupies Mas Atierra and
another Mas Afuera. It will also serve as an indication that the Pink-footed
Shearwater is essentially a bird of the Sub-Antarctic Zone of surface waters,
which might be sufficient reason for its selection of Mas Atierra, the adjacent
island of Santa Clara, and Mocha Island, which lies much farther southward
and close to the continental coast; and why at the same time it avoids Mas
Afuera, which lies in waters that approach a sub-tropical character.
During the southern spring season of 1932, Mr. D. S. Bullock found the
‘Fardela Blanca’’ to be an abundant resident of Mocha. His manuscript states
658 OCEANIC BIRDS OF SOUTH AMERICA
that the bulk of these shearwaters spend the daylight hours at sea, and that
toward nightfall they gradually move close to the land. Not until it is almost
dark, however, do they begin to come ashore in their countless thousands.
In some parts of Mocha Island, the steep hillsides are literally honeycombed
with the burrows of the Pink-footed Shearwater. The birds spend the nights
in these holes, but at the first indication of dawn they return to the ocean.
The favorite nesting sites are in the forest, particularly in places where the steep
hillsides have steps or ledges of soil supported by the roots of trees and shrubs.
Two photographs Mr. Bullock has sent well illustrate a number of such bur-
rows, at an altitude of about 250 meters above sea level. The burrows are some
10 to 13 centimeters in diameter and they frequently reach to 3 meters in length.
On November 27, Mr. Bullock found a few pairs of Pink-footed Shearwaters
in the nest-chambers, but apparently no eggs had yet been laid. He inferred,
from observation and hearsay, that the height of the nesting season comes to-
ward the end of December or during the first half of January. Residents of
Mocha informed him that if a fire is kindled on the beach at night, the Pink-
footed Shearwaters flutter in like moths and smother the flames with their
scorched bodies.
Anthony (1925, 284) observes that the Pink-footed Shearwaters in California
appear to feed entirely upon small fish, and that their numbers at any one point
depend upon the concentration of the latter.
FLESH-FOOTED SHEARWATER
Puffinus carneipes
Puffinus carneipes Gould, 1844, Ann. Mag. Nat. Hist., 13, p. 365 (small islands off Cape Leeuwin, Australia).
Names: Pale-footed Shearwater. Several subspecies have been described but are not currently
recognized.
Characters: A large, stout-billed, blackish, or almost ‘‘chocolate’’ shearwater, resembling
Puffinus griseus but with a pale bill and feet and dark wing-lining.
Adults (sexes alike): General color of dorsal surface sooty or fuscous black, with faintly
indicated edgings of ashy brown, which become enhanced through wear, particularly on the mantle
and scapulars; longer scapulars, wing coverts, and quills of wing and tail blackish brown, darker
than the back, the primaries somewhat paler in the usual style on their inner webs, their shafts
pale basally; pileum, nape, and sides of head fuscous black like the back, with a slight tinge of
ashy gray on the lores, infraorbital region, and ear coverts; cheeks and entire ventral surface
sooty brown, with a distinct ashy gray or Quaker drab tinge on the throat, cheeks, and fore part
of breast, and with a faint suggestion of the same on the flanks and abdomen in fresh plumage;
under wing coverts and axillaries sooty brown, as dark as the breast. Iris brown; bill flesh color,
with the tip and the anterior part of the culmen black; feet and legs flesh color, the webs somewhat
buffy and the tarsus and outer toe externally brown.
6 males and 6 females, New Zealand and Lord Howe Island: wing, 317-329 (321.2); tail, 109-
115.1 (113.2); exposed culmen, 37.6-43.3 (41); tarsus, 51.6-56.3 (54.2); middle toe and claw,
62.7-67 (65) mm.
A half-grown nestling is covered with sooty gray down, uniform above and below, and has
dull fleshy pink feet and a fleshy purplish bill, dark at the tip.
Eggs, elongate-ovoid, white, 73 x 46, 72 x 44.5 mm. (Oliver; 1930, 116).
Distribution: Breeds on islands off southwestern Australia and northern New Zealand, and
at Lord Howe Island; ranges to Japan and eastward to Juan Fernandez and California.
FLESH-FOOTED SHEARWATER 659
This Australasian shearwater seems to be a bird of exclusively sub-tropical
breeding range. From its headquarters, between Australia and the Chatham
Islands, it goes regularly northward through the tropics to Japan. Some-
where in the North Pacific certain of the birds seem to lose themselves, so to
speak, among the great flocks of migrant Sooty Shearwaters (Puffinus griseus),
which subsequently travel southward down the longest and straightest sea-
coast in the world, namely that between Alaska and Cape Horn. This, at least,
would be a logical explanation of why the Flesh-footed Shearwater seems to
be a regular though not common visitor accompanying the Sooty Shearwaters
down the west coast of North America, where Beck (1910, 66) has collected
specimens off California during April, August, September, and November. That
certain of the birds may continue southward across the equator in the eastern
Pacific is indicated by Beck's subsequent capture of a male about 13 kilometers
off the coast of Mas Atierra Island, Juan Fernandez group, on February 9, 1914.
This specimen had elongated and sharply pointed claws, such as are common
among petrels long away from their nesting grounds. The gonads were reduced,
and the bird was in worn body plumage but with recently renewed quills in
the wings and tail. Its measurements agree in every way with those of spcci-
mens from New Zealand, Lord Howe Island, and the coast of California, as I
have elsewhere pointed out (Murphy, 1930, 11).
Many fragmentary studies of the life history of this large and powerful bird
have now been superseded by the recent work of Falla (1934, 249). According
to this scholarly investigator, the Flesh-footed Shearwater appears annually
off the northern coast of New Zealand early in September, after an absence at
sea of three to four months during the southern-hemisphere winter. The nightly
cleaning out of old burrows and excavation of new ones begins during the month
after atrival. By early November the entire population seems to be coming
ashore every night, and laying begins late in this month, continuing until about
December 10. The first chicks hatch shortly before the middle of January, and
half-grown nestlings have been found on March 10. Thereafter the chicks begin
to feather rapidly and are fed less frequently, or not at all. By the beginning of
May all the burrows are empty, and no more of the Flesh-footed Shearwaters
are to be seen in coastal waters. This species, like the Gray-backed Shearwater,
is at some nesting localities brought into close association with the far-famed
tuatara (Sphenodon punctatus). Reptile and bird are sometimes encountered in
the same burrow at islands in the Bay of Plenty.
Long before dark, during the breeding period, these shearwaters approach
the land, but they do not actually begin to come ashore until dusk. In this
respect, as in many others, their habits appear to resemble closely those of the
Manx Shearwater, as quoted elsewhere in this volume from the investigations
of Lockley. In early October many burrows contain pairs of the Flesh-footed
Shearwaters at night and a few are to be found housing single birds during the
day. By November the din associated with courtship and mating has waxed to
a loud nightly chorus, the shearwaters beginning before they alight to utter
their short mewing note, which is more or less like that of a kitten. This is
660 OCEANIC BIRDS OF SOUTH AMERICA
doubtless the call to which Buller (1884, 234) referred as a cry like that of a
child in pain. Mating displays begin after dark on open ground near the burrows.
A high pitch of excitement is rapidly reached, many birds ambling and wobbling
about with swaying necks thrust forward, uttering all the while a guttural
chuckling note interspersed with a sobbing intake of the breath. The climax
of such demonstration is reached when paired birds strike an ecstatic attitude,
with their beaks close together, and set up a duet of loud squeals.
During January, when the birds are changing guard, they arrive later in the
evening, and when bringing food for the young, later still. On days of strong
wind, the foraging Flesh-footed Shearwaters have a tendency to work directly
away from their nesting ground into the wind. On one occasion, when a south-
west breeze was registering a steady force amounting to five of the Beaufort
scale, Falla observed many of the shearwaters feeding late in the afternoon at
a point fully 135 to 140 kilometers to windward of their nesting ground. He
remarks that petrels can obviously feed to best advantage when moving against
the wind, besides which they are thereupon strategically placed to run before
the breeze when they return, heavily laden with food for their offspring. It
would be interesting to learn the effect upon food, and upon metabolism of
such a necessarily long-delayed delivery. Stevenson (1933, 155) has shown that
the last remnants of food in the full stomach of certain song birds will be voided
in less than 2.5 hours. This, in connection with the habits of fish-eating birds,
which sometimes bring their catch from a long distance to their young, raises
the question as to whether sea fowl can in any way delay the digestion of the
food they have swallowed in order to transfer it practically unchanged and in
unreduced quantity.
Adult Flesh-footed Shearwaters collected in December almost invariably had
the alimentary tract filled with a substance resembling bright green mud, the
nature and origin of which have not been determined. Cephalopod beaks, too,
are often found in the stomachs. This species is also fond of fish, which it
seems better able to capture than many of its relatives. An explanation of this
appears in the actions of the birds around fishing-boats, for, according to Falla,
they will frequently dive and follow the bait of a sinking line to the extraordi-
nary depth of from 3 to 5 meters, not infrequently hooking themselves during
the process.
GREATER SHEARWATER
Puffinus gravis
Procellaria Gravis O'Reilly, 1818, Voy. Greenland Adj. Seas, p. 140, pl. 12, fig. 1 (Cape Farewell, Greenland,
from first locality named).
Names: Hagdon. A synonym of the specific name is major, besides which the species has been
listed under the name cénereus.
Characters: A large brown and white shearwater, with a white wing-lining and a conspicuously
dark pileum, which is divided sharply on the side of the head from the white cheeks.
Adults (sexes alike): Pileum and entire head, above the line of the gape, dark sooty brown,
except for a slight whitish mottling beneath and in front of the eye; remainder of dorsal surface
generally sooty brown, most of the feathers broadly margined with a paler and more ashy brown,
which is lightest and most conspicuous on the scapulars and inner secondaries; upper tail coverts
GREATER SHEARWATER 661
like back except that the longer underlying coverts are white, only slightly tinged or mottled with
brown, the tips forming a conspicuous band above the rectrices; quills of wing and tail fuscous
black, the concealed portions of the inner webs somewhat paler; greater wing coverts with a
‘frosted’ appearance and narrowly edged with whitish; ventral surface, caudad to belly, white,
the white cheeks being sharply detined from the dark lores, infraorbital region, ear coverts, and
sides of nape; behind the brown cap the white encroaches dorsally so as to form a complete or
nearly complete light collar; feathers of central lower breast and belly with ashy brown tips,
forming a somewhat mottled elongate, dirty brown patch; flanks with a varying amount of brown-
ish spotting on the tips of the longer feathers; feathering of thighs and under tail coverts sooty
brown, the latter tipped with whitish; axillaries white, with brownish subterminal blotches;
under wing coverts white, some of those along the bend and edge of the wing having brown shaft-
streaks and centers. Iris brown; bill dark horn-color, sometimes blackish; feet flesh color, with the
outer toe and the outer side of tarsus brownish black.
12 males from the coast of Argentina: wing, 317-332 (323); tail, 105.7-115 5 (110.5); exposed
culmen, 43.2-48.5 (46.1); tarsus, 57.5-61.9 (59.3); middle toe and claw, 71.5-75.4 (73.3) mm.
11 females from the South and North Atlantic: wing, 309-337 (325); tail, 105-116 (111.6);
exposed culmen, 41.8-47.2 (44.6); tarsus, 52.8-61 (57); middle toe and claw, 66.8-75.5 (70.7) mm.
I have seen neither a downy young nor a description of one.
Eggs taken at Inaccessible and Nightingale Islands, on November 11] and 14, together with
others attributed, perhaps incorrectly, to dates in March, May, and September, are of the ordinary
shearwater type, white, smooth, dull-surfaced, and variable in shape. Average measurements of
10, as recorded by Mathews, are 77 x 49 mm. His longest example measured 84.5 x 50, and the
smallest 70 x 46.9 mm. Averages of four others, measured by Jourdain and recorded by Bent, are
77.7 x 48.6 mm.
Distribution: Breeds at the islands of the Tristan da Cunha group; ranges over the South At-
lantic southward to the latitude of the Falkland Islands, and also migrates into the North Atlantic
as far as European seas, Labrador, Greenland, and the arctic circle.
Although the Greater Shearwater is one of the most widely distributed of
Atlantic sea birds, its only known breeding grounds, at the islands of the Tristan
da Cunha group, have been but recently discovered, despite the fact that at least
a proportion of the shearwater population remains in the South Atlantic
throughout the period of northern-hemisphere summer. At this same season
there are vast numbers of these birds on the Grand Banks of Newfoundland, and
elsewhere in North Atlantic fishing-grounds. They are common, too, at times
in the lower bay of New York, and the American Museum has specimens from
as far north as Greenland, which is, in fact, the type locality of the species.
As many Greater Shearwaters are to be found in the South Atlantic throughout
the year, so, too, apparently, do others remain in the North Atlantic during
_the normal breeding season. In the Berlin Museum I have examined December
specimens from the waters about Madeira.
Wynne-Edwards (1935, 254) has shown that in spring the Greater Shear-
water, like the two other common visiting petrels from the southern hemisphere,
migrates northward up the western half of the North Atlantic, after crossing
the tropics with great rapidity. At about the 45th parallel the birds spread out,
the movement reaching Davis Strait by early June and simultaneously beginning
to extend northeastward. Prior to July there are no records to eastward of the
great circle arc joining northern Ireland and the Azores, and it is probable that
the species does not normally occur east of this line before the second week in
August, by which time it has attained its maximum abundance in high latitudes.
662 OCEANIC BIRDS OF SOUTH AMERICA
After mid-September the numbers of Greater Shearwaters in the eastern North
Atlantic for the first time become comparable with the earlier abundance in
the west. The southward migration, on the other hand, is to a great extent
concentrated in the eastern Atlantic, except for the return movement of the
birds that have summered in American and Greenland waters. There is thus a
sort of circulation of Greater Shearwaters on the same general plan as the cir-
culation of the North Atlantic surface waters. The facile inference that this is
in some way correlated with the movements of plankton is, writes Wynne-
Edwards, likely to be wrong. It may conceivably be due, however, to a drift
in the direction of the prevailing westerly winds, for which hypothesis Dixon
(1933, 122) has found support in similar seasonal movements of birds confined
to the southern oceans.
During a series of voyages from Southampton to Cape Town made, I judge
from the context, chiefly during late summer and autumn, Swinburne (1886,
196) regularly observed Greater Shearwaters between the Bay of Biscay and
latitude 9° S., where they thinned out for a time. In about latitude 20° S.,
however, he encountered .them again, after which they became increasingly
abundant toward the Cape of Good Hope, and particularly so between latitudes
40° and 45° S. On one occasion, near the Bijouga Islands (latitude 11° N.), he
saw such dense flocks of this species that they were at first mistaken for land.
During my South Atlantic cruise in the ‘Daisy,’ I observed Greater Shear-
waters frequently, and captured specimens in March, 1913, about halfway
between the Tristan group and the coast of South America. The stations,
together with those of many other South Atlantic records nearer the coast of
the continent, and extending from Brazil to the Falkland Islands, are shown on
the chart of Dabbene (1923, 27).
During the course of the Brewster-Sanford Expedition, Beck took 23 speci-
mens off Mar del Plata, Province of Buenos Aires, on October 5, 1914. Here, at
distances up to 30 kilometers from shore, the birds were mingled, in waters
around the Argentine fishing fleet, with Manx and Sooty Shearwaters, Giant
Fulmars, Cape Pigeons, Shoemakers, and Mother Carey’s chickens. The asso-
ciation was similar in ecological composition, and partly the same in its make-
up of species, as might have been encountered off the Strait of Belle Isle, New-
foundland.
The Mar del Plata specimens were all in fine plumage, as well as in breeding
condition. The gonads were enlarged, without exception, and on many of the
labels Beck has written, ‘‘ready to breed.’’ The moult is well illustrated by
numerous birds collected two or three months earlier in the year. Thus August
examples from Labrador, and particularly a female collected at Julianehaab,
Greenland, on August 7, have new primaries, the wings of some being as short
as 265 millimeters, or only 80 per cent of the mean length for adults of the
species.
The first strong clue to the breeding grounds of the Greater Shearwater came
in January, 1906, when Lord Crawford's yacht, the ‘Valhalla,’ lay to for four
days off Tristan da Cunha. Numbers of the shearwaters were observed about
GREATER SHEARWATER 663
the island and still more at a distance of a day's sail to eastward. In 1908, Mr.
P.C. Keytel visited Tristan and made an expedition to Inaccessible Island, where
he succeeded in obtaining breeding birds and a number of eggs (Bent, 1922, 66).
According to Mathews (1932, 28), most of the known eggs have been collected
during November, which seems to mark the height of the laying season. The
suggestion by the same author that these shearwaters have been found breeding
also during the months of March, May, and September is, as he himself suggests,
probably due to careless labeling or careless memory on the part of the islanders.
Bent, for example, refers to an egg said to have been collected at Tristan da
Cunha on May 29, 1917. During the visit of Wilkins (1923, 499) to Nightingale
and Inaccessible Islands, in May, 1922, many Greater Shearwaters were found
in their burrows on the hillsides. The birds were betrayed by their croakings,
but an examination of the gonads of several specimens collected showed no
indication of nearness to the breeding season. Nevertheless, during the night
these birds were flocking to the islands by hundreds, apparently to occupy many
burrows observed to be empty during the hours of daylight. Such use of the
nesting site by Procellariiformes during the non-breeding season is, as noted in
other biographies, a relatively recent discovery, and one worthy of thorough
investigation. The curious point in connection with the Greater Shearwater is
that May 21, when Wilkins found so many on the nesting ground, is close to
the average date of arrival of spring migrants in the latitude of the southern
and middle Atlantic states in North America.
There has been more or less question as to whether this species is the famous
“*Pediunker’’ of the Tristan folk. Mathews believes that he has definitely con-
nected that vernacular name with the Gray Petrel (Adamastor cinereus), and
states that the Greater Shearwater is called merely “‘petrel.”’
The Greater Shearwater is, like many of its far-wandering congeners, a fish-
ing petrel, which follows moving shoals of surface-swimming fishes as well as
the squids that come to the uppermost layers of the ocean during the hours of
half-light or on dark days. In pursuit of its prey, this shearwater stoops sud-
denly, flops against the water on its breast, and then plunges and literally flies
through the dense medium, always coming into the air again to swallow its
catch. Collins (1884, 313) states that Greater Shearwaters, following the dories
of North Atlantic fishermen, will dive repeatedly even after the elusive bubbles
made by oars. Whales or porpoises, according to Wynne-Edwards, invariably
have an attendant flock. The birds seem to feed to some extent upon cetacean
feces, which may account in part for the large numbers of cephalopod beaks
found in their stomachs.
Collins says, furthermore, of this species that the migrants into the North
Atlantic form great flocks when they first arrive in spring, and again before
their departure in autumn. During most of the northern summer, however, they
are far less gregarious, each bird working for itself and joining others only in
scrambles for food, when they all appear audacious, quarrelsome, and insatiable.
The cod fishermen formerly took advantage of their numbers to use the birds
both as food and as bait. The Hagdons were lured within range by the expedient
664 OCEANIC BIRDS OF SOUTH AMERICA
of first chumming up the Mother Carey's chickens through the use of fish en-
trails. The smaller birds quickly attracted the larger, which sailed in, scattered
the lesser petrels, and voraciously proceeded to snap up the food, all the while
uttering harsh and raucous calls. They were then caught on mackerel hooks,
and during the ‘seventies of the last century it was not unusual to see from 200
to 500 of these birds hanging from the rigging of a Grand-Banker.
Such a toll of life, added to accounts of thousands found dead upon South
Carolina beaches after an August hurricane (Wayne, 1894, 85), and the count-
less numbers which appear each summer off the Atlantic coast of North America,
indicates an amazingly large breeding population for three such tiny dots in
the sea as the islands of the Tristan da Cunha group, more especially since this
shearwater has apparently become all but exterminated at Tristan itself, and is
not yet known to breed at Gough Island, or at any other locality in the South
Atlantic or elsewhere. The same problem of seemingly incredible productive-
ness applies, however, to numerous other oceanic birds, and I have sometimes
suspected that the breeding grounds of certain insular petrels passed the peak
of overcrowding ages ago, and than an annual breeding season may have become
replaced by a longer reproductive rhythm. This would allow a multiple use of
a limited breeding area. Such a hypothesis, while not yet demonstrable, would
at least account for many adult but non-breeding petrels and albatrosses regu-
larly encountered during the calendar nesting season in parts of the ocean far
from their breeding range. Systematic banding operations, coupled with regular
tabulation of the nesting periods through several seasons, would be the one
way to solve such problems.
GRAY-BACKED SHEARWATER
Puffinus bullert
Puffinus bulleri Salvin, 1888, Ibis, p. 354 (New Zealand).
Names: Also known as Buller’s Shearwater.
Characters: Distinguished from other small shearwaters belonging to the field of this book
by its gray back in conjunction with the dark crown, wings, and tail, and the white ventral surface.
Buller (1888, 240) aptly says that the long neck and long tail of this species make it look like a
diminutive shag.
Adults (sexes alike): Pileum and anterior part of cervix deep, or dark mouse-gray, forming a
cap contrasting with the adjacent upper parts; lores and auriculars mouse-gray, chiefly dark in
tone, interrupted in a varying degree with white; usually a whitish mark just above the eye;
posterior portion of cervix and sides of neck, the scapulars, interscapulars, and upper tail coverts
mouse-gray or deep mouse-gray, more or less varied with darker sub-terminal borders and grayish
white edgings; rump deep mouse-gray, relieved in most instances with paler edgings; jugulum,
breast, and abdomen immaculate white; line of demarcation on sides of neck and breast nebulated
gray and white; sides white, in two specimens with indications of gray; flanks mouse-gray, the
feathers narrowly tipped with grayish white; general aspect of lower tail coverts white, bordered
and tipped with gray, the lateral feathers being varied with mouse-gray, particularly on the outer
web, and the partially concealed central ones being deep mouse-gray, apically at least; primaries
outwardly black, the shorter ones frosted with gray, and the inner webs of all extensively white;
the secondaries except innermost, mouse-gray, margined with grayish white, and largely white
on inner web; the innermost secondaries blackish brown, some of them tipped with grayish white;
tertials blackish brown, more or less washed with gray and tipped with grayish white; lesser wing
GRAY-BACKED SHEARWATER 665
coverts blackish brown; middle coverts blackish brown, the outermost sometimes mouse-gray with
paler edgings; greater coverts light mouse-gray, margined with grayish white, the innermost
blackish brown; alula and primary coverts black; lining of wings and axillaries white; inner edge
of wing with a narrow broken border of mouse-gray and blackish brown; two lateral rectrices
mouse-gray (or dark brown frosted with gray), tipped with grayish white; the other rectrices
black (Loomis, 1918, 149).
Iris brown; bill blue or bluish, the tip and culmen black; feet and legs inwardly flesh color,
including the two inner toes and the webs; outer toe and outer side of tarsus blackish brown. The
blue of the bill may represent a heightening of color characteristic of the breeding season, for
many non-breeding specimens are marked as having “‘grayish’’ beaks.
24 males and females from Chile, California, and New Zealand: wing, 275-300 (287.3); tail,
114-131.8 (125.3); exposed culmen, 39-44.6 (41.8); tarsus, 49-53.5 (51.5); middle toe and claw,
58.5-65 (61.5) mm.
Large downy nestlings from New Zealand are neutral gray, only slightly darker above than
below. Their bills and feet are colored like those of adult birds, except that they are paler, with
less pigment in the dark parts of the skin.
Eggs from Poor Knight's Island, New Zealand, are ovoid, white, and measure between 63 x
41.5 and 68 x 43.6 mm. The average of six is 66.4 x 42.8 mm. (Falla, 1924, 41).
Distribution: Primarily a shearwater of the Sub-Tropical Zone of surface water, breeding on
islets off North Island, New Zealand, and ranging eastward to the west coast of South America
and northward to California.
Until recently the Gray-backed Shearwater was regarded as one of the rarest
of all petrels in collections. The example upon which Salvin founded the species
was discovered on a New Zealand beach by Sir Walter Buller, in 1884. During
the next thirty-eight years only a few more specimens were obtained, and then
Mr. R. A. Falla observed the species in large numbers off Poor Knight's Island,
east of the northern extension of New Zealand, and later discovered its breeding
place at these islands. In the meanwhile, Beck (Loomis, 1926, 146) had collected
a considerable number of specimens off Point Pinos, California. Here, between
September 2 and November 8 of two different years, he found them fishing in
company with Sooty and Pink-footed Shearwaters, both of which are migrants
from southern South America. He also saw a lone Gray-backed Shearwater
following a school of Spanish mackerel, as if the bird and fish were in search of
common prey. When the fish sounded, the shearwater alighted on the surface
of the water. On still another occasion, a foggy, drizzly day in the middle of
October, he succeeded in luring Gray-backed Shearwaters within range of his
gun, off Point Pinos, by tossing dead birds into the air. His California notes
state that the flight of this small species is, in a light breeze, very similar to
albatross flight, there being much less of wing-flapping than in the case of the
Pink-footed Shearwater. Several of the California specimens taken during
October had the gonads slightly enlarged.
To switch from the northern hemisphere to the southern, Beck encountered
this species off Valparaiso, Chile, while on the Brewster-Sanford Expedition,
during the southern summer of 1914, and collected a number of specimens be-
tween February 24 and March 12. All of these were moulting the quills and
had resting gonads. The date might indicate that the birds had crossed the
southern Pacific after the end of the New Zealand nesting season. On the other
hand, a still undiscovered American breeding ground is at least possible.
666 OCEANIC BIRDS OF SOUTH AMERICA
Falla (1934, 250) has recently worked out the following interesting details
concerning the life history of this species.
Off northern New Zealand the Gray-backed Shearwaters return from their
wanderings to the vicinity of their native islands between late August and the
end of September. Refurbishing their old burrows, or the task of excavating
new ones, together with the collecting of nesting material, begins in October
and has been observed until after the middle of November. The first week of
December seems to be the uniform egg-laying season; most of the chicks hatch,
according to Falla, before the end of the same month, but the incubation period
suggested by this seems an incredibly short one for petrels. Falla’s further
comment that the chicks are still clothed in down and show no contour plumage
as late as February 24, makes it appear that many of the young do not hatch
before January at the earliest. Most fledglings leave the burrows about the end
of March, and by a month later very few of them are to be seen in the coastal
waters. The general breeding habits seem to correspond closely with those of
the Flesh-footed Shearwater (Puffinus carneipes), with the difference that the
Gray-backed species has not been seen to approach its nest before dark, as its
larger relative sometimes does. Such differences in behavior are doubtless
codrdinated with difference in size, as the latter affects the relations of these
two shearwaters with predacious birds, such as hawks or even certain gulls.
The Gray-backed Shearwaters make a mewing call when they approach the
land after dark.
On the Poor Knights the burrows are found mostly on slopes facing the sea, but a few were
found by Falla under roots of trees half a mile inland. The burrows are three to four feet in length
and near the end is placed the nest consisting of twigs, roots and leaves. Beyond the nest is enough
space for the bird to turn round. . . . In some of the burrows the tuatara [Sphenodon punctatus]
is found, the relation between bird and lizard usually being not amicable but apparently one of
mutual toleration. Occasionally the tuatara may eat a young petrel, but as this lizard feeds at
infrequent and often long intervals, little damage is done. Falla states that a tuatara even when
hard pressed was unwilling to approach a sitting shearwater (Oliver, 1930, 121).
Stomachs of adult Gray-backed Shearwaters examined during September con-
tained squid beaks and small sharp pebbles. Young taken from the nests later
in the same month had a green substance in their alimentary tracts, which was
perhaps not food but some secretion like bile. Many of the birds Beck shot off
Valparaiso during February and March had their stomachs crammed with
small crustaceans.
SOOTY SHEARWATER
Puffinus griseus
Procellaria grisea Gmelin, 1789, Syst. Nat. 1, pt. 2, p. 564 (southern hemisphere, 35°-50° S. = New Zealand).
Names: Dusky Shearwater; Black Hadgon or Haglet; “‘Fardela’’ and ‘*Yegua"’ in southern
South America; ‘‘Dofia”’ or ‘‘Dofiana”’ in Peru. This widely distributed petrel has been described
under a variety of specific names, which include fuliginosus, cinereus, tristis, chilensis, amaurosoma,
and stricklandi.
Characters: A dark gray or blackish bird, distinguished from other shearwaters of similar
size by its prevailingly whitish under wing coverts, and from all within our present field, except
Puffinus tenuirostris, by its dark bill and feet.
SOOTY SHEARWATER 667
Adults (sexes alike): Color of the dorsal surface sooty brown, with obsolete paler margins on
many of the feathers, the concealed portions generally gray; scapulars and wing coverts darker,
inclining toward blackish brown, the median coverts more or less frosted with hoary gray; quills
of wing and tail blackish brown, the primaries paler on their inner webs, the shafts basally ivory-
white; lower back, rump, and upper tail coverts sooty brown like the pileum and mantle; sides of
face paler and more ashy than the crown, a white stripe on the lower eyelid, and in some instances
a faint whitish mottling beneath and in front of the eye; ventral surface close to deep mouse-gray
in fresh plumage, becoming buffy or brownish with wear and fading; axillaries sooty brown,
rather darker than the breast; under wing coverts mostly white, with blackish shaft-lines, and
mottled or fringed with ashy brown.
Loomis (1918, 133) has shown that this shearwater exhibits a considerable dichromatic range
in pigmentation. In light examples the chin and throat are grayish white; the basal and sub-
terminal portions of the feathers of the jugulum and breast are also grayish white, giving to the
ventral surface a mottled appearance; the shorter axillaries are variegated with grayish white;
the under coverts of the wing are white, with only slight indications of gray. In extremely dark
examples the chin and throat are deep gray, the basal portions of the feathers of the jugulum and
breast are lighter gray, and the general aspect of the under coverts of the wings is gray instead of white.
Iris brown; bill blackish, but sometimes horn-color on the mandible; legs and feet externally
blackish, but blue or purplish on the webs, inner toes, and the inner side of tarsus.
40 males and females from the Atlantic and Pacific coasts of North and South America: wing,
280-309 (293); tail, 84-99.2 (89.4); exposed culmen, 38-45.6 (41.7); tarsus, 52.5-59.5 (55.4);
middle toe and claw, 50.9-71.5 (63.1) mm.
Loomis’s figures, based upon a much larger series of specimens, substantially agree with these
dimensions, and show that the sexes do not materially differ in size. The wing-expanse of a male
taken off Rio de Janeiro on July 29 was 107 cm.
Chicks are covered with Quaker drab down, much longer and of looser texture on the dorsal
surface than below.
Eggs collected by Beck at Wollaston Island, near Cape Horn, at the end of December, 1914, are
thin-shelled and fragile, elongate, white, with a slightly pitted surface, and much stained from the
soil. They measure 77.3 x 45.5 and 78.1 x 47.6 mm. Others, taken at Wollaston and Bayly Islands,
at the same season of a subsequent year, are described as ‘‘thick-shelled, with a slight chalky
coating and distinct pores. Average of seven eggs 73.4 x 47.7, max. 81 x 45 and 70.75 x 50.25 mm.,
min. 67.25 x 44.25 mm."’ (Reynolds, 1935, 92). Bent (1922, 86) gives extreme measurements of
34 eggs from a number of localities, but the variation is so wide as to cast doubt upon the identity
of certain included specimens.
Distribution: Breeds in southern South America and in the sub-antarctic region of New Zealand;
Magellanic Islands near Cape Horn are actual nesting sites, as well as (probably) various parts of
the table-land of northern Chile. The flight-range extends from the southern Pacific and Atlantic
Oceans northward to the neighborhood of the arctic circle, including the coasts of Kamchatka,
Alaska, Labrador, Greenland, and Europe.
The Sooty Shearwater is an abundant sea bird throughout the length of the
oceans on either side of the Americas, from the latitude of Cape Horn north-
ward to arctic waters. It is particularly numerous along the Pacific coasts of
North and South America. A hundred thousand birds, according to Beck, is a
low estimate of the number one may see in the course of a single day when the
migrating hordes are southward bound off California shores. Sooty Shear-
waters have been taken at Point Pinos in every month in the year, but are
particularly in evidence during the northward movement of April and May,
and on the return flight in autumn (Beck, 1910, 65). The same is eminently
true in South America, for there is neither a locality nor a season in which their
passing bands have not been sighted between Panama and the southern tip of
668 OCEANIC BIRDS OF SOUTH AMERICA
the continent. Along the Peruvian coast they appear to confine themselves
rather closely to the zone of cool upwelling water near the steep desert shore,
and it is noteworthy that the expedition of the California Academy of Sciences
did not encounter the species in the offshore waters about the Galapagos
Islands. Farther southward, however, beyond the great bend in the South
American coast that comes near the southern border of Peru, the path of the
migrating birds spreads over a broader front, and during the Brewster-Sanford
Expedition Beck found Sooty Shearwaters as far at sea as the neighborhood of
Juan Fernandez, where he collected specimens during February. On his voyage
to these islands he observed that their numbers gradually thinned out as those
of the Pink-footed Shearwater increased. .
It would not pay to list the captures and sight records of Sooty Shearwaters
along the west coast of South America, because the places named would repre-
sent an unbroken geographic series of localities, the dates would cover the
entire calendar year, and the numbers of birds would be legion. Beck’s field
journal refers to particularly great flocks off Salaverry and Chilca, Peru, during
January and June, respectively, and off Valparaiso and Ancid, Chile, during
February and March. Examples collected in November and December on the
Chilean coast include many in breeding condition. Lane (1897, 312) observed
a characteristic concentration of these shearwaters in the bay of Corral on
November 3, 1890. The lines, he writes, were ‘miles in length. . . . Froma
distance they presented a remarkable appearance, numbers being settled on the
water, whilst the air above was full of them, flying in regular succession from
the rear to the front of the column."’ The following record from my own
journal is one of a number that might be selected to illustrate the unfailing
abundance of this species along the coast of Peru:
Independencia Bay, November 15, 1919. Late in the afternoon we passed
into the Trujillana Channel, the northern entrance of the bay, our trawler, the
‘Alcatraz,’ pitching and covering us with spray as she nosed into the rolling
seas. Smoky clouds, ripped from the concealed promontory of Isla Vieja, were
scudding across our deck. Out at sea the day wind had already died down, and
we could see far offshore the line of calm; but within the bay the gale seemed
to be constantly increasing. Large flocks of petrels were playing in the wind
close to the north point of Vieja. These included Mother Carey's chickens,
Cape Pigeons and Silver-gray Fulmars, but the Sooty Shearwaters, or Dofias,
were the most abundant of all the birds; there were certainly upwards of 10,000
in a single dense flock that passed us, the long-winged, graceful shearwaters
flying high and low in the howling wind over the choppiest areas of water. Do
they seek such whipped-up places because the wind and waves bring their food
to the surface? Whatever the reason, they were marvelously at home in the
terrific gusts, while small groups of cormorants, resting upon the water along
our course, hesitated before even attempting to rise.
It is only in the warm-water zone, off Ecuador and Colombia, that our
knowledge of the courses and seasons of the Sooty Shearwater is markedly
deficient. Very likely the migrants tend to hurry across the tropical gap that
SOOTY SHEARWATER 669
separates the cool upwelling waters of the Humboldt and California Currents.
We know, at any rate, that this species is susceptible to the diseases incident to
abnormally high ocean temperatures in the littoral of northern Peru. At times
of the malady or ‘‘peste,’’ which follows the incursions of the warm current
known as El Nifio, Sooty Shearwaters, no less than Peruvian Cormorants and
other endemic species of the Humboldt Current, die and wash ashore by thou-
sands. At intervals of years, the shores of the Gulf of Guayaquil become lined
with their carcasses.
Darwin, as recorded by Gould (1841, 137), writes that he had never seen so
many birds of any other sort together as he once saw of these shearwaters behind
the island of Chiloé during January, 1835.
Hundreds of thousands flew in an irregular line for several hours in one direction. When part
of the flock settled on the water the surface was blackened, and a cackling noise proceeds from them
as of human beings talking in the distance. At this time the water was in parts coloured by clouds
of small crustacea. The inhabitants of Chiloe told me that this petrel was very irregular in its
movements; sometimes they appeared in vast numbers, and on the next day not one was to be seen.
By many subsequent authors the above quotation has been applied to the
Pediunker (Adamastor cinereus), but it clearly refers to the Sooty Shearwater,
cinereus being the name which Gould had applied to the latter species in his
“Birds of Europe’’ (1837). Furthermore, Darwin states that his notes refer to
a petrel “‘likewise known to be common in the Northern Hemisphere.”’ Finally,
Adamastor cinereus certainly does not occur in the inland waters behind Chiloé.
It is a bird of distinctly pelagic rather than coastal distribution, coming to land
not in continental regions but at remote islands such as Tristan da Cunha.
About the southern end of the South American continent, and northward
along the Atlantic coast, accounts give a similar picture of frequent aggregation
of the Sooty Shearwaters in vast flocks. Thus Dabbene (1902, 384) reports
thousands in Beagle Channel near Harberton Harbor, and the observations of
Paessler (1914, 273), Aplin (1894, 212), Friedmann (1927, 144), Reid (1884, 273),
and Collins (1884, 320) carry the record northward along the coasts of Argen-
tina, Uruguay, Brazil, and into the North Atlantic to Bermuda and the Grand
Banks of Newfoundland.
Upon the basis of comparison of New Zealand examples of the Sooty Shear-
water with specimens from more than a score of localities along both coasts of
South America, and with large series of migrants from the North Atlantic and
North Pacific, I have shown that only one race appears to be determinable
(Murphy, 1930, 8). The world-wide individual variation proves to be approxi-
mately the same as the individual variation of a fully representative series from
a single locality.
Loomis’s (1918, 133) specimens demonstrate that a complete moult of the
plumage takes place on migration during the early months of northern-hemi-
sphere summer. He also reports that the range of pigmentation in this species,
leading in one direction toward examples with grayish white chins and throats,
a mottled belly, and almost clear white under wing coverts, probably represents
actual dichromatism rather than wear. Albinism, he states, is not uncommon.
670 OCEANIC BIRDS OF SOUTH AMERICA
The discovery of the American breeding grounds of the Sooty Shearwater
was one of Mr. Beck's notable feats during the course of the Brewster-Sanford
Expedition. The nests were unearthed at Wollaston and Deceit Islands, just
north of Cape Horn, at the New Year season of 1915. Burrows on Wollaston
Island were under dense shrubs, far up on a ridge, nearly 5 kilometers from the
ocean, and some of them had evidently been abandoned before completion,
because water had seeped into them from the surrounding soil. The least acces-
sible of the burrows were located under boulders. Only two eggs were found,
both heavily incubated, and lying in wet nest-chambers without lining except
for a few feathers or straws. The sitting birds fought very savagely when
hauled into the daylight, Beck describing their struggles and outcries as the
most vigorous he had ever encountered among petrels of any sort. Such behavior
seems to be typical of the species. Lane remarks that wounded birds, which he
hauled into his boat off the Chilean coast, attacked everything most ferociously,
not only biting oars and cordage but even each other, and screaming as they
tore out feathers in wholesale fashion. Wetmore (1926, 52) also says that
examples which blundered aboard his steamer at night gave raucous calls with
widely opened mouths, and resented handling by biting savagely.
A more recent account of a visit to the breeding grounds near Cape Horn is
that of Reynolds (1935, 92):
The nights which we spent at Deceit and Wollaston were made hideous with the noise of
Petrels passing overhead. I attribute the most ghastly sounds to this species, although it was
always too dark to make certain, and at Wollaston Storm-Petrels were certainly seen flying over
us at night. The following is an entry in the diary: —‘‘22/12/32 at Wollaston, heard lots of
Petrel noises like choking cats—‘‘cha-whee-whoo’’—grating and choking with noise like gurgling
intake of breath and lancing, working often to a climax.'’ The sound is not altogether unpleasant
ata distance, but uttered by those birds passing at close quarters it is appalling.
During the crossing to Barnevelt and back great flocks were passing towards Cape Horn, and
late in the evening between Deceit and Herschel towards Wollaston. On Deceit, in spite of the
noise at night, we searched unsuccessfully for the nests . . . —large mounds of Azorella covering
a small headland were honeycombed with old burrows containing thick white egg-shells, which
may have belonged to this Shearwater.
On Wollaston we used the dog and took four sets of 2/2 and 2/1; the eggs were hard-set except-
ing in the supposed clutches of two. Two more clutches were taken on Bayly Island. . . .9
taken from burrow with hard-set egg at 10 a.m., stomach nearly empty, but a little grit and green
slime in crop. . .
The birds peck vigorously, and our hands were badly cut in removing them from the burrows.
I collected one . . . and the remainder, when liberated, flapped over the ground for some time
before taking off towards the sea.
This Shearwater breeds on steep ground at a height of 500 feet or more. The burrows vary
from three feet to several yards in depth, and are well hidden under stunted trees growing about
outcropping rock, and in much drier places than the holes of Oceanites. The nesting grounds,
similarly to those of the Storm-Petrel, are extremely difficult to detect. The burrows frequently
run beneath the roots of the evergreen beach.
No doubt the breeding grounds are extensively distributed throughout the
seaward fringe of Fuegian islands, including Staten Island. During August,
1915, Beck saw great flights of Sooty Shearwaters which had recently concen-
trated along the northern coast of Staten Island, and on subsequent days an
SOOTY SHEARWATER 671
irregular, steady, southward movement along the eastern coast of Tierra del
Fuego. Bennett (1926, 314) records specimens from the Falkland Islands, and
states that two have been taken from nesting burrows at islets, covered with
tussock grass, but thus far no eggs have been discovered. Mr. D. S. Bullock
has sent to the American Museum a male taken at Mocha Island, Chile, on
December 12, 1932, and I infer from his accompanying notes that a few pairs
of the “‘Fardela Negra’’ may nest there, but that it is much less common than
the Pink-footed Shearwater or Fardela Blanca.
Nothing else is known of the breeding of the Sooty Shearwater in America,
except for the still somewhat inconclusive records from the coastal table-land
of northern Chile, which have been referred to in Part I of this book. Strese-
mann (1924, 63) reports that a party of prospectors on the plantless pampa
inland from Cobija, Chile, found during the month of June a colony of web-
footed birds on the eastern slope of the Cerro de Colupito, at an altitude of
1500 meters. The nests were in the shelter of rocks and contained one chick
each. The latter were slightly larger than pigeons, of a uniform gray color,
and were tentatively identified as Puffinus griseus, a conclusion apparently
justified by the nocturnal activities of other sea birds at neighboring localities
during March and April, and by the finding of several buried and mummified
specimens referable to this species.
On the western side of the Pacific, the Sooty Shearwater is the mutton bird
of New Zealand, just as Puffinus tenuirostris is the mutton bird of Tasmania and
southeast Australia. It is still economically important for its flesh and oil, for,
when the Maoris ceded Stewart Island to the Crown, they reserved the express
privilege of taking the shearwaters under authority of the New Zealand govern-
ment. Oliver (1930, 123) states that at present about 250,000 young are annually
collected and preserved, and that more than 300 persons are employed in the
industry. According to Travers (1873, 220), the Maorioris of Chatham Islands
went everybody one better in their use of the stomach oil. They regarded the
fluid as a delicacy, and were accustomed to hold the young petrels over their
mouths, allowing the oil to drain from bird to man by the most direct route.
Highly significant, moreover, is the following sentence from Oliver's account,
when it is considered in connection with the precise biological data obtained
by Lockley during his study of the Manx Shearwater. “‘The evidence of the
mutton-birders who, for instance, find an albino in the same burrows during
several successive years, indicates that the same parents occupy the same burrows
year after year.”’
Falla (1934, 251) states that the Sooty Shearwaters come ashore at islands
off northern New Zealand during October, and that the species there burrows
in harder ground, and also makes deeper tunnels than do other shearwaters.
The chamber is usually well Jined with sticks, dry grass, and leaves. That
escape from the light is probably more important to this bird and other species
than the seclusion or thigmotactic environment of a burrow, is indicated by
several bits of evidence, including the fact that in one place at the Chatham
Islands the Sooty Shearwaters occupy a dark cave, laying their eggs on the
672 OCEANIC BIRDS OF SOUTH AMERICA
sandy floor below the rock wall (Archey and Lindsay, 1924, 189). Falla states
that the sitting birds sometimes utter a monotonous, crooning note during the
day. Very much remains to be learned about the alternation of the incubating
parents in this species as among other petrels. Stuart-Sutherland (1922, 58)
records the interesting information that at Puysegur Point, New Zealand, where
Sooty Shearwaters are frequently killed by striking the lantern of the lighthouse,
all examples that he has picked up after one destructive night have proved to
be male birds while on another such occasion they have all been females.
Falla has drawn the interesting conclusion that the extent of the annual
migration has a close correlation with the schedule of breeding dates of various
sub-antarctic petrels. Thus he finds that among New Zealand species none of
those which annually cross the equator into the northern hemisphere lay their
eggs earlier than November. Furthermore, there is a marked regularity about
the egg-laying period of such species, and their preliminary behavior of court-
ship, burrowing, etc., occupies a relatively short period.
Species which are permanent residents in southern waters, on the other hand,
have a far more extended breeding season, and show irregularity or a wide range
in their dates of laying. Some such birds even nest during the winter.
Puffinus griseus is an excellent example of the first of these two categories,
and P. assimilis of the second.
The food of the Sooty Shearwater apparently includes a wide variety of
surface organisms. Stomachs of examples collected by Beck in the Magellanic
channels were crammed with small fish, while in the same locality a stomach
examined by Oustalet (1891, 162) contained only swimming crustaceans.
Darwin noted organisms of both these types, and also cuttlefish. Specimens I
dissected at various seasons along the coast of Peru contained, respectively,
anchovies, the remains of ten or more squids, and the larvae of several types of
crabs, including Pinnixa transversalis and Cancer polydon, one bird having eaten
about fifty of the latter. One stomach also contained a mass of gravel. On a
number of occasions I had an excellent opportunity to watch the birds feeding.
On January 15, 1925, for example, when bound northward, about 15 kilometers
west of Ferrol, in the early afternoon my vessel plowed through a flock of Sooty
Shearwaters that covered perhaps a square kilometer of the ocean. The day was
calm, and the birds in the steamer’s path flopped or “‘ran’’ to either side, making
frequent and frantic dives. I had a rare opportunity to watch them closely as
they progressed beneath the surface, and to note that they literally ‘‘flew’’
while submerged, using their wings with slow, powerful strokes. Again, I
have seen more distant and undisturbed rafts of the birds moving along, half
in air, half on the water, in pursuit of shoals of anchovies or pejerreyes. In such
cases the rear of the flock would continually pour forward over the vanguard,
so that the whole formation seemed to roll like a flattened hoop across the water.
Bent's (1922, 87) general description of the flight and feeding of this species
is as follows:
The flight of the sooty shearwater is swift, graceful, and strong; like other species of Puffinus,
it can sail for long distances on its long, stiff wings without even a tremor, except to adjust them
SOOTY SHEARWATER 673
slightly to the wind, rising at will over the crests of the waves or gliding down into the valleys
between them and turning as the albatrosses do by lowering the wing on the inner side of the
curve and raising the wing on the outer side, both being held in a straight line, the angle of incline
depending on the sharpness of the curve. It frequently flaps its wings, however, when occasion
requires it and uses them freely in its squabbles for food. It sometimes experiences a little difficulty
in rising from the water in calm weather, but ordinarily it does so very rapidly. It swims lightly
and swiftly on the surface and dives below it occasionally in pursuit of food, using its wings freely
under water. It has frequently been caught on the trawl hooks of the cod fishermen.
Not infrequently I have seen Sooty Shearwaters come thumping on deck at
night and Mr. Charles Fagan, wireless operator of the S. S. ‘Santa Elisa,’ tells
me that, on a foggy January night near Point Parifias, he has seen these birds
pile on deck until they were layers deep—in some places level with the bulwarks
—so that seamen had to be ordered out to shovel them overboard with coal-
scoops. After such a visitation, the decks were well smeared with regurgitated
fish. Wetmore (1926, 51) saw forty or fifty come aboard a vessel near Lobos de
Afuera Island, during the evening of May 7, when he made the following note
upon the terrestrial progression of this bird:
Those that came aboard fell sprawling on deck and then scuttled along, half erect, with rapid
awkward steps. The obliquely placed feet, with the comparatively slight flexure of which they
were susceptible, made their stride short and stilted. Some hurried into dark corners; others at-
tempted to clamber into the lighted passageways, pulling themselves over the raised thresholds of
the doorways by aid of their bills.
SHORT-TAILED SHEARWATER
Puffinus tenuirostris
Procellaria tenuirostris Temminck, 1835, Nouv. Recueil de Planches Color. d'Ois., 5, text facing pl. 587 (seas
north of Japan).
Names: Mutton Bird; Slender-billed Shearwater; Whale-bird in Alaska. Synonyms of the
specific name include brevicaudus, intermedius, curilicus, and obscurus.
Characters: Closely similar to the Sooty Shearwater (Puffinus griseus), from which it is doubt-
fully to be distinguished in life by its lesser size, shorter bill, and usually darker wing-lining.
Adults (sexes alike): Dichromatic to a slightly greater extent than Puffinus griseus. The darker
phase is thus described by Godman (1908, 152):
General color above sooty black, with obsolete margins of lighter brown to the feathers of the
upper surface; wing coverts like the back, with the same obsolete paler edges, which are slightly
grayer at the ends of the greater coverts and secondary quills; bastard-wings and primary coverts
and quills black; the inner primaries slightly shaded with ashy gray, the secondaries rather browner
than the primaries: tail feathers black; head like the back, sooty black; sides of face also sooty
black, grayer on the lores, cheeks, and throat; under-surface of body sooty brown, with obsolete
ashy edgings to the feathers; under tail coverts uniform sooty brown; under wing coverts dull
ashy gray, mottled with sooty brown round the entire edge of the wing; axillaries sooty brown;
quills blackish below, with an ashy shade along the inner webs for nearly the entire length.
Loomis (1918, 138) states that in the light phase the general aspect of the under surface of the
wings is decidedly grayish white; the chin and anterior portions of the throat are likewise grayish
white, sometimes mottled with gray; white, tinged with gray, also prevails at the bases of the
feathers of the jugulum and breast.
Iris brown; bill blackish brown; legs and feet purplish black, with the outer toe and outer
side of tarsus black.
8 specimens, 6 of which are males: wing, 263-277 (272); tail, 76.9-85.8 (80.9); exposed cul-
men, 32.2-34 (33); tarsus, 49.4-52.9 (50.9); middle toe and claw, 57.5-62.2 (59.6) mm.
674 OCEANIC BIRDS OF SOUTH AMERICA
Nestling clad in brown down. Two eggs from Bass Strait measure 72 x 44 and 73 x 47 mm.
(Oliver, 1930, 124).
Distribution: Breeds at islands in Bass Strait and in neighboring districts close to Tasmania
and southeastern Australia. Ranges northward and eastward to Bering Sea, the west coast of
North America, and Panama.
The Short-tailed Shearwater, the famous ‘‘Mutton Bird’’ of the Furneaux
Islands in Bass Strait, is an Old-World species which, like several of its con-
geners, appears from time to time along the American side of the Pacific. Mr.
Beck, while collecting for the California Academy of Sciences, found it not
uncommon off Point Pinos, California, between the months of October and
January of several different years, the birds being sometimes especially numerous
during November and December. A female taken in this region on December 2
had the ovaries functionally enlarged. Loomis (1918, 138), who reports upon
these specimens, is inclined to regard them not as returning migrants bound for
South American breeding stations but, rather, as ‘strays that have missed their
way and, falling in with the rear guard of the Sooty Shearwaters, have come
down the wrong coast, the American instead of the Asiatic.’ This assumption
is likely to be correct, for the only Short-tailed Shearwaters yet reported from
the field of this book are a number that Hallinan (1924, 306) found floating in
an exhausted condition in the vicinity of Naos Island, Bay of Panama, on June
8, 1915. A male which he placed on ice revived and became active.
This species is one of the shearwaters characterized by dichromatism, some
examples being much darker than others. Whereas most specimens have the
under surface of the wing dark gray, those of the light phase have under coverts
that are decidedly grayish white, a condition which would make such birds
particularly difficult to distinguish in life from the Sooty Shearwater. The two
extreme phases of the Short-tailed Shearwater are completely linked by birds of
intermediate stage but, under any circumstances, both the form and the shortness
of the bill serve adequately for the specific determination of examples in the
hand. Loomis found that among 44 specimens of this shearwater the culmen
measured between 29.7 and 35 millimeters, while among 165 skins of Puffinus
griseus the range was from 38.3 to 47.3 millimeters.
In the region of Bass Strait the Mutton Bird is a species of ancient fame and
of considerable economic importance. Not only do the young constitute the
preferred food of the aboriginal islanders, but they are also salted and preserved
in great quantity for shipment to Tasmanian and New Zealand markets. The
shearwaters have been much studied at their breeding grounds, and the follow-
ing summary is drawn chiefly from the writings of Davies (1846, 13), Elwes
(1859, 397), Gould (1865, 459), Buller (1873, 315; 1888, 230), Montgomery
(1898, 209), Littler (1910, 165) and Oliver (1930, 124). So far as the strictly
biological aspects are concerned, the fact of outstanding importance is the
remarkably close resemblance between the behavior of this southern-hemi-
sphere species and that of the Manx Shearwater (Pwffinus puffinus) in western
Europe. Such correspondence furnishes at least a preliminary basis for valuable
general conclusions.
SHORT-TAILED SHEARWATER 675
The breeding Mutton Birds are protected by Tasmanian law, but on March 20
the open season begins, and the young may be legally taken thereafter until the
surviving fledglings leave the breeding grounds in May. As recently as 1910
about half a million of the chicks were being captured and prepared as food
each year.
Formerly the adults as well as the young were slaughtered in great numbers,
the feathers no less than the oil and flesh being utilized. For a few days after
the first arrival of the shearwaters, toward the end of September, fence-traps
were constructed on the hillsides, leading to pits into which the birds tumbled
after leaving their burrows at daybreak. By this means thousands were taken
each morning and, according to Elwes, two men and a woman once collected
during a single season a ton of feathers, representing some 56,000 birds. The
surviving population was then left alone, but when the chicks were nearly full
grown the petrels were made to yield a second toll.
In the commercial exploitation of the well-grown chicks, they are hauled
out of their burrows and killed by squeezing, after which they are strung up by
the head so that none of the stomach oil may be lost before it is intentionally
drained off. The oil, which varies in quantity from a teaspoonful to about
200 cubic centimeters, is clean, pure, burns well in Jamps, and ts also used as a
lubricant. More recently it has been refined and used medicinally for it is re-
puted to contain a high proportion of two or more vitamins, and to have virtues
similar to those of cod-liver oil. At Launceston, Tasmania, it sells for four
shillings per gallon. After the oil has been taken out, the young birds are split
and salted.
The Short-tailed Shearwaters congregate in immense flocks about their home
islands during September and, shortly after sunset, they begin to fly in toward
their warrens. One of the earliest calculations regarding the numbers of the
birds is that of Flinders, as quoted by Littler and Buller. Flinders witnessed
the flights in Bass Strait during December, 1798, and describes a stream of shear-
waters 50 to 80 yards deep and more than 100 in breadth, flying as compactly
as their wing movements would allow, and continuing thus for one hour and
a half at a rate little inferior to the speed of pigeons. By allowing 9 cubic yards
of space for each bird, and assuming a velocity of 30 miles per hour, Flinders
concluded that there were more than 150 million birds in the flock he observed!
Similar flights, requiring the greater part of a night to pass a given point, have
been witnessed as recently as October, 1909.
When the shearwaters first return to their breeding grounds, descending birds
rest on the soil outside their burrows, doubtless in anticipation of the arrival
of their mates. Their mouths and throats are at this time full of a pasty sub-
stance with the appearance and smell of tinned salmon. This sounds like small
crustaceans, and Walter (1903, 219) tells us that their food consists, in fact,
largely of the shrimp-like creatures known as whale-feed, organisms which
make the water look reddish over extensive areas; in their efforts to escape from
the path of a vessel, the birds sometimes eject great quantities of these creatures.
On the nesting ground there is at first more or less struggling and bickering
676 OCEANIC BIRDS OF SOUTH AMERICA
overt possession of the burrows, the preparation of which takes about six weeks
after the return from migration. Both birds of a pair work at cleaning out the
old homes or excavating new ones, making the sand and earth fly for some dis-
tance from the entrance. When the nests have been renovated, the population
disappears for a space of a month or longer, after which it returns, the paired
birds darkening the sky increasingly for four or five successive days. Indeed,
the clouds of birds, flitting about the island at the beginning of the laying
season, are so dense that they cause night to be ushered in before the usual hour.
The din that they make can never be forgotten. The incessant sounds are vari-
able but always harsh and unearthly. The departure of the shearwaters at the
first streak of dawn is, however, as uncannily silent as the arrival is clamorous.
Davies states that the Mutton Bird rookeries can be smelled at a distance of
11 kilometers from the islands.
At Green Island in Bass Strait, according to the same author, the numbers of
the Short-tailed Shearwaters were formerly so greatly in excess of the available
space for burrows that more eggs were laid among the shrubbery on the surface
than underground. Montgomery reports that in well-populated rookeries
there may be as many as nine entrances to burrows in each square meter of
the surface.
Egg-laying begins late in November, and the young appear about January 15,
the period of incubation being close to 50 days. The chicks remain silent in
their burrows during the day. After dusk there is a rush of parents from sea,
which soon becomes bewildering, for tens of thousands come whistling in like
bullets, passing the head of an observer until it seems dangerous to stand up.
This influx, which is, of course, long after the end of the courtship stage, is
conducted in silence, but presently the ground begins to emit extraordinary
gurglings, groanings, and laughter, as the hundreds of thousands of chicks are
receiving their one meal during the twenty-four-hour period. About 10 o'clock
the muffled clamor ceases, while the young, doubtless, are digesting, and the
adults resting from their labors. Many of the latter come forth from the burrows
to sleep in the open air. About half-past two in the morning, a rising murmur
announces the awakening of the rookery, and the adults all scramble like
an army of land-crabs or small mammals to the higher ridges of their island,
where they stretch their wings high over their backs and launch into the air,
always facing the wind before taking flight. The last of them disappear be-
fore daylight.
The full-grown young are abandoned by their parents late in April, and
successive days of hunger eventually pull the trigger of the instinct which spurs
them to find their own way to the water. The ‘“‘birders’’ of Tasmania declare
that the chicks devour more or less gravel as soon as they come out of their
burrows. Mortality from diurnal enemies, or as a result of physical accidents .
on the rough terrain, is very high, but the surviving chicks cover the neighbor-
ing seas in rather sluggish black flocks, which spend many days upon the water,
engaged much more in diving and surface-feeding than in flight. Later they
break up into smaller aggregations and ultimately leave the coast.
MANX SHEARWATER 677
MANX SHEARWATER
Puffinus puffinus puffinus
Procellaria puffinus Brunnich, 1764, Orn. Bor., p. 29 (Faroe Islands).
Names: Synonyms of the specific name include anglorum and arcticus.
Characters: A black and white shearwater, much larger than Audubon’s or than any of the
forms of Puffinus assimilis.
Adults (sexes alike): General color of the dorsal surface sooty black, including the head, wings,
and tail; lores, sides of face, and ear coverts blackish, more or less mottled with white along the
junction with the ventral plumage; a distinct infra-orbital, and a fainter supra-orbital, stripe
white; cheeks, post-auricular region, and sides of neck and breast freckled with ashy gray (or with
sooty brown in more worn plumage), owing to the presence of dark terminations on the otherwise
white feathers; ventral surface white, the lower flanks and thighs, and the outermost under tail
coverts, being boldly blotched with sooty black; under wing coverts and axillaries white, the
latter with variable single or double spots of ashy or sooty black near their tips; a slight mottling
all around the bend of the wing; quills of wing and tail glossy sooty black on the outer webs,
paling considerably on the inner, the shafts basally lighter in color. Iris brown; bill dark horn-
color, the ramus of the mandible grayish; back of tarsus, outer toe, and lower half of middle toe
black; front of tarsus and remaining parts of toes light pink, the webs bluish gray.
7 males (4 from the South Atlantic, 3 from the British Isles): wing, 230-244 (237.6); tail,
68.6-76.4 (72.6); exposed culmen, 34-36.2 (34.8); tarsus, 43.7-46.3 (44.7); middle toe and claw,
47.8-51.1 (49.2) mm.
3 females (1 from the South Atlantic, 2 from the British Isles): wing, 228-238 (232); tail,
74.5-79 (76.1); exposed culmen, 35.1-36.6 (35.7); tarsus, 43.2-45.8 (44.2) mm.
Since the species reaches South America only as a migrant from the northern hemisphere,
descriptions of the eggs and downy young are not pertinent.
Distribution: Breeds in the North Atlantic Ocean at islets off Iceland, the Faroes, British Isles,
coast of Brittany, the Azores, Madeira, the Salvages and Bermuda. Migrates southward to the
coast of Brazil and Argentina.
Only recently has the Manx Shearwater been recognized as a regular migrant
into the South Atlantic, although there are numerous older records for the
coast of Brazil to which sufficient attention has not been paid. During the
South Atlantic cruise of the brig ‘Daisy,’ in November, 1912, I saw this shear-
water frequently among other petrels. It dived freely for food that I tossed into
our wake, and I might have captured many but for the fact that the aggressive
Shoemakers (Procellaria) and other large petrels crowded the Manx Shearwaters
away from my hooks. Finally, on November 4, in latitude 33° 28’ S., longitude
45° 42’ W., a position to eastward of Uruguay, I succeeded in capturing a female
in brilliant unworn plumage on a fishhook baited with loggerhead turtle meat.
Both the glossy feathering and the very slender bill of this specimen stamp it
as probably a bird of the year. It exactly matches known fledglings from
western Europe. On November 7, 1920, Wetmore (1926, 50) found an emaciated
Manx Shearwater on the beach south of Cape San Antonio, Buenos Aires. Dur-
ing the course of the Brewster-Sanford Expedition, Beck saw many feeding
about the Argentine fishing-boats, in company with Greater Shearwaters and
other sea fowl, and on October 5 and 9, 1914, he collected four males off Mar del
Plata. All of these are adults in which the quills appear to have been recently
renewed, while the moult of the body plumage is under way. One is fresh and
glossy, and three are more or less bleached and worn. All are indistinguishable
from British and Bermudian specimens.
678 OCEANIC BIRDS OF SOUTH AMERICA
We have, of course, no clue to the source of these South Atlantic birds, for
the breeding range of the Manx Shearwater has very wide latitudinal limits in
the eastern North Atlantic. Evidently the bulk of the western European breed-
ing population is supposed to remain chiefly within the Old World littoral
district during the northern winter. Wynne-Edwards (1935, 268) writes:
The Manx shearwater frequents the offshore zone rather than the pelagic. It is the commonest
shearwater in British seas, where some at least are to be found at all seasons. Oceanic records are
scarce, for the birds become decidedly rare beyond about 200 miles from the coast.
While the Manx Shearwater does not nest within the South American region,
its life history has perhaps been studied more fully than that of any other
member of its genus, and a summary of its behavior may prove illuminating in
connection with innumerable unsolved problems in the régime of other more or
less closely related Procellariiform birds.
Although primarily a breeding species of the eastern Atlantic, the Manx
Shearwater is also resident at Bermuda, from where the American Museum has
one specimen. A bird was found incubating an egg in a hole among the rocks
on an islet in Castle Harbor during the month of April (Reid, 1884, 274). The
character of the nesting site, the presence or absence of vegetal material as a
lining in the nest-chamber, and many other details of the life history seem to
be highly variable and to depend upon the particular environment. Thus Turle
(1891, 8) reports that at the Blasket Islands, off the western coast of Ireland,
he found these shearwaters’ eggs lying without exception upon bare earth, while
elsewhere vegetation serves not only as a mattress for the egg, but also as a
sort of ‘‘property’’ used by the adult birds during the procedure of courtship.
The most detailed investigations of this species are those of Lockley (1930, 202;
1931, 202). From his model studies the factual data in the following brief notes
are summarized.
Upwards of 5000 pairs of Manx Shearwaters nest at Skokholm, a small island
covered with heather, bracken, and grassland, and situated well off the coast of
Pembrokeshire. The birds begin to arrive for spring and summer occupation of
their breeding grounds as early as February 9. Toward the end of the month
they are plentiful. In autumn the adults commence their exodus before the
fledglings, and the last of the latter leave the island by the middle of October.
This means that during two-thirds of the year the bulk of the shearwaters are
resident, and that they devote, on the average, four months to a winter migra-
tion at sea. From coastal waters close to the nesting ground there are, however,
records of occurrence during every month of the year except December and
January.
Upon reaching the vicinity of their summer range, the Manx Shearwaters
apparently experience an immediate impulse to go in search of last year’s
burrows. For a time these will be occupied by single birds. February snows or
severe frosts may cause all of them to abandon the island for a few days, but
they are back in force as soon as possible, and in March and April they begin
to be found within the burrows in pairs. The holes are visited with great
MANX SHEARWATER 679
regularity at night, but the circumstances governing the presence or absence of
the birds by day are highly variable. Activity of the adults is greatest, or at
least begins earliest, on dull and misty days, and also on moonless or over-
clouded nights. Few returned to Skokholm, for instance, and few remained in
the burrows throughout the day, while the moon was waxing between April 3
and 7, 1930. Even later in the reproductive period, it is apparent that the liveli-
ness of the birds is in inverse ratio to light, for a bright moon is sufficient to
dampen considerably the volume of their calls, the general phrasing of which
is recorded by Lockley as ‘‘kuk-kuk-kuk-oo.’’ Furthermore, calm weather is
unfavorable to the thriving of the shearwater colony. Strong wind, on the
other hand, enables the incoming birds to advance freely and slowly against it,
with their wings quivering like those of a kestrel, and to make easy landings.
It offers equal advantages over quiet air when the shearwaters take off from the
doors of their abodes to return to sea.
The observations of Lockley show that the Manx Shearwaters customarily
form flocks toward evening on the ocean at some distance from the breeding
ground, and there spend considerable time, especially in calm weather, resting,
washing, and preening. Each addition of a new group to the flock brings about
a general hectic rising, which is followed by a new settling down. Beginning
about two hours after sunset, or earlier in dark weather, the influx toward the
island begins, continuing well into the night. Nocturnal activity, with much
calling, is then carried on in the open until about half-past two o'clock in the
morning, when it ceases rather abruptly as the shearwaters all hurry either into
their burrows or off to sea.
Evening after evening the homeward-bound shearwaters fly directly to their
burrows, each usually dropping accurately at its own front door. If no sound
is then forthcoming from the earth, the newcomer appreciates the significance
of the silence and waits outside for its mate, after the arrival of which the two
wrestle with and caress each other, and utter unearthly variations of their call.
The character necessary for recognition appears to be inherent in the voice and,
even to human ears, there is an almost infinite individual variation in tone or
pitch—some birds have high notes, some low, some harsh, and others soft.
Although the preliminary stages of courtship seem to be marked by a certain
promiscuity or indefiniteness, Lockley believes that this is apparent rather than
real, and that it means merely that certain migrants of early spring blunder into
burrows haphazardly in order to escape the daylight. At any rate, his banding
experiments reveal the astonishing fact that numbers of identical pairs are found
mated at the same nests during successive years, and that there is much evidence
for, and none against, the belief that these shearwaters mate for life. It remains
to be determined whether such a relationship is due to direct interaction between
individual birds of opposite sex, or only to a shared homing sense that leads
each independently back to the site of the former season.
Since some burrows cave in during the winter, and since the shearwater
population of Skokholm is now increasing, there is each spring a shortage of
ready-made burrows. Furthermore, a certain proportion of the birds are neces-
680 OCEANIC BIRDS OF SOUTH AMERICA
sarily breeding for the first time, and one or both members of some pairs have
in consequence no fixed locality-ties. This leads not only to the excavation of
new burrows, but also to territorial struggles for old ones. Under such circum-
stances, mutually antagonistic pairs of shearwaters may occupy the same burrow
for some time. Lockley finds that the first pair to produce an egg usually main-
tains possession and ousts the rival claimants.
Nest material, in the form of vegetation gathered near the entrance of the
burrow, is collected a week or so before the egg appears, early in May. If an
egg is removed, no second is laid, but the despoiled parents continue to frequent
the burrow at intervals until well after midsummer. After egg-laying, the
adult birds carry on their conversation and caresses entirely underground. One
parent may remain for three or four, or even five, days in continuous incubation,
obtaining its only relief by turning the egg and altering its own position at
least once each day, and by meeting its mate in the burrow at night. As incuba-
tion progresses the birds become increasingly shy or wild with reference to a
human intruder. This reaction oyerbalances any opposite trend such as might
result from increasing familiarity.
On occasion both parents may be found together in the nest during the day,
even well toward the end of the long incubation period, which Lockley dis-
covered to last from 52 to 54 days. The young shearwater may begin to call
within the egg a full day before breaking through the shell. The newly hatched
chick is continuously brooded for a week or thereabouts, and is thereafter visited
and fed regularly by both parents once in twenty-four hours. The feeding pro-
cess takes place immediately after the nightly 1eturn of the adults, and before
the beginning of any audible ‘‘conversation’’ among the family of three. Ifa
parent is intercepted and caught as it is about to enter the burrow, it is only a
matter of seconds before it disgorges all the food it is carrying.
The mesoptyle down of the chick sprouts at about the 16th day after hatch-
ing, and reaches its maximum length on the 35th day. By the 42d day the
quills begin to project from the tips of their sheaths, and by the 60th, 61st, or
62d day the youngster is completely feathered, though with more or less down
still attached to the tips. At this time it is suddenly, completely, and forever
deserted by the parents, after which it remains for a time in its burrow, fasting
and drawing upon its own reserve of fat. The remaining traces of down and the
drying sheaths of the quills drop in a ring around it, but very little excreta
appears during this period of starvation. After six days or thereabouts, the no
doubt still-expectant chick makes its way to the mouth of the burrow, where
it sits throughout the night. Later it plucks up courage to leave its home, and
to wander about near the burrow, walking on its toes but with the tarsus form-
ing a sharp angle with the ground, and moving with a curious springy gait, a
few steps at a time. Very close to half-past two in the morning all such chicks
invariably scramble back into their nests, to remain until the following night-
fall. For a period of between 11 and 15 days the forsaken fledglings thus test
the outside world, until hunger presently joins with instinct in spurring them
to make a further bid for liberty. Therefore, at an age which is normally 72
MANX SHEARWATER | 681
or 73 days, they begin to head for the sea. They appear to know the shortest
route toward the water, which may be through a positive reaction to the
brighter sky over the ocean, or to the distant sound of waves.
If the wind is strong on the fateful night, the fortunate young shearwaters
may undertake a successful first flight directly from burrow to ocean. But ona
calm night their spasmodic efforts result in what Lockley calls a ‘‘flying walk,”
which may degenerate into a pathetic scramble over the bogs and rocks, and
through the bracken, requiring not only the remainder of the dark hours but
perhaps the next night as well, before they can reach the water. Under such
circumstances, the chicks crouch beneath any convenient hiding-place at the
approach of daylight, which reduces them to helpless torpor, and during this
period large numbers of them fall victims to gulls, crows, and hawks. The
average weight of healthy fledglings at this time is from 368 to 425 grams
(453:6 grams = 1 pound). Many are lighter, particularly those which have
delayed their exodus too long and which lack stamina to complete the short
but essential step toward the first self-sustaining phase of life.
The outbound chicks, which demonstrate so well the fundamental pattern,
including the nutritional stimulus, of a migration, blunder straight over the
led ges and cliffs when they reach them, tumble or glide to the water, and at once
swim and dive, flying beneath the surface with their wings, remaining below
for periods as long as twenty-four seconds, and also drinking the water while
they float, lifting the head as a young chicken does to allow it to run down
their throats. They paddle, rather than fly, offshore, and form large and some-
what sluggish flocks on the ocean. When they do take wing, their flight is for
a time distinctly more labored than that of adults.
Such a plan of life history, as worked out for the Manx Shearwater by
Lockley, is doubtless applicable to many species of the genus, and in part to
less closely related Procellariiform birds. It goes far, in fact, to give meaning
to many random and hitherto puzzling observations regarding breeding petrels
‘in various parts of the world, and it rationalizes the data I have given about the
abandonment of fledgling albatrosses by their parents.
The moult of the Manx Shearwater takes place during the rearing of the
young, a condition obtaining among many other species of petrels, in which the
incubation and fledgling periods are prolonged.
The food of the birds of Skokholm comprises mainly young herrings. On
the open sea west of Ireland, Jespersen (1930, 116) found remains of fish and
small cephalopods in Manx Shearwater stomachs.
Tue Least SHEARWATERS
I have shown (Murphy, 1927, 2) that the smallest members of the genus
Puffinus, with wings less than 22 centimeters in length, form two natural groups,
one of which is made up of birds with ‘‘blue-black’’ and the other of birds with
‘‘brown-black’’ upper surfaces, and that these two groups are to be associated
with distinct oceanic zones, one sub-antarctic, the other pan-tropical.
682 OCEANIC BIRDS OF SOUTH AMERICA
The distinctions may be more fully set forth as follows:
1.—Upper surface varying in the different races between slate color and slate black, fading
greatly with extreme wear, but always without a trace of brown hue in fresh feathers; inner vanes
of the primaries largely white; under tail coverts mostly white (entirely so among all forms
examined except the Madeiran race); part of loral space between culminicorn and angle of mouth,
white; color of legs in life, blue. Range: extra-tropical seas, chiefly in.the temperate zone beyond
30° S. latitude, but with one north temperate race (at Madeira). ....... Puffinus assimilis.
2.—Upper surface varying from blackish brown to sooty black, but always brownish rather
than slaty; inner vanes of primaries without white; under tail coverts largely or entirely dark;
part of loral space between culminicorn and angle of mouth, mostly dark; color of legs in life,
flesh color. Range: tropical seas, extending just north of the tropic of Cancer at the Bonin and
Bahama Islands, and to an isolated northern outpost at Bermuda .... .. Puffinus lherminieri.
Puffinus lherminieri has its typical race in the western tropical Atlantic, and
another at the Galapagos Islands. A highly distinctive subspecies of Puffinus
assimilis appears to be found along the northerly edge of the Sub-Antarctic Zone
of surface water all around the globe. Within our region it breeds in the Tristan
da Cunha area.
TRISTAN SHEARWATER
Puffinus assimilis elegans
Puffinus elegans Giglioli and Salvadori, 1869, Ibis, p. 68 (South Atlantic Ocean, latitude 43° 54’ S., longi-
tude 9° 20’ E.).
The typical form of this subspecies was described from the western South Pacific, the reference
being as follows:
Puffinus assimilis Gould, 1838, ‘Synops. Birds Austr.,’ part 4, Append., p. 7 (“New South Wales’’ = Nor-
folk Island).
P. a. elegans is, however, so well marked a race that it may be described without reference to the typical race.
Names: The members of this group of petrels have been badly confused and the present sub-
species has been frequently listed under such names as obscurus, affinis, and australis. Puffinus
assimilis munda (Salvin), described from the South Pacific, also appears to be a synonym. Mathews
(1933, Bull. Brit. Orn. Club, No. 371, p. 25) states that the name munda is untenable and proposes
anew name, kvhliana. However, nothing has been advanced to show that munda is not synonymous
with elegans, and the latter name has priority over all others (Murphy, 1927, 5).
Characters: A large, but relatively short-billed, race of Puffinus assimilis, the feathers of the
slaty dorsal plumage narrowly margined with white.
Adults (sexes alike): Entire upper surface close to slate color, the feathers of nape, sides of
neck, back, wing coverts, secondaries, and tail coverts margined with white, most broadly (2 mm.)
on the external and terminal parts of the secondaries; concealed portions of dorsal feathers grayish
white; inner two-thirds of inner vanes of primaries white to within 20 or 25 mm. of their tips;
pileum slightly more blackish than back, and lacking white borders on the feathers; lores speckled,
white on their lower halves, the dark color of the pileum descending below and behind the eye,
with a mottled boundary; a narrow white stripe on the lower eyelid; sides of breast covered with
slaty, white-margined feathers which blend gradually with the uniform white plumage of the
ventral surface; lining of wings and under tail coverts white like throat and breast. Bill blackish
above and terminally, blue on the mandible and toward base of culminicorn; feet and legs blue,
with the outer toe and outer side of tarsus blackish; webs yellowish.
The above description and the following measurements are based upon Pacific, not South
Atlantic, specimens.
6 adults of both sexes: wing, 182-196 (190.5); tail, 64-69 (66.8); exposed culmen, 24-27.5
(25.8); depth of closed bill at base, 8.4-10; least depth of bill, 6-6.6; width of bill at base, 10-11.5;
tarsus, 39-41.5 (40.3); middle toe and claw, 45-48 (47.1) mm.
TRISTAN SHEARWATER 683
Egg: Oval, smooth, and without gloss; the average measurements of an unstated number from
Gough Island are 50 x 35 mm. (Mathews, 1932, 27).
Distribution: The Sub-Antarctic Zone of the southern oceans, breeding at Gough Island, and
now or formerly at the islands of the Tristan da Cunha group. Pacific and Indian Ocean breeding
grounds are still undiscovered.
The type locality of the Puffinus elegans of Giglioli and Salvadori is southeast
of the Cape of Good Hope, and about equidistant from there and from Gough
Island, but considerably south of the latter. Mathews (1932, 27) has examined
skins and eggs from Gough. He adds that the bird appears to be little known
among the present-day folk of Tristan da Cunha, but that he had received a
single specimen from that group in the collection of Mr. J. G. Gordon, and
also an egg without data said to pertain to the same bird.
During the visit of the ‘Scotia’ to Gough Island, in the month of April, a
pair of these shearwaters was captured in a burrow in a steep grass-covered
bank on the side of a ravine. The attention of the Scottish naturalists was
drawn to the birds by their loud croaking. The bank was honeycombed with
similar burrows, and numbers of the petrels were seen at sea around the island
(Clarke, 1913, 284).
Practically nothing seems to be known of the life history of this subspecies,
and little concerning other races of Puffinus assimilis. Jespersen (1933, 198)
gives a chart showing positions in which alleged examples of Puffinus assimilis
were sighted during a voyage across the Pacific Ocean. The latitudes of the
records, however, taken in conjunction with the author’s remarks on page 197,
make it almost certain that all his observations relate rather to forms of Puffinus
Lherminieri.
The type specimen of this shearwater was collected on March 2, 1866. In
both appearance and measurements it agrees exactly with seven examples of,
““munda’’ or ‘‘kuhliana’’ from the South Pacific, suggesting that the two are
the same. Latitude, not longitude, is the principal geographic circumstance
correlated with racial and specific differences among the southern Tubinares.
Within the tropics each ocean may, indeed, have its own forms, but in the belt
of westerly winds these birds may, as Gould was so fond of supposing, ‘‘make
the circuit of the globe.”’
Banks collected specimens in the South Atlantic, near the coast of South
America and north of latitude 41° S. (Hooker, 1896, 64). Salvin (1876, 236)
records an example from latitude 48° 27’ S., longitude 93° west of London. It
is also probably the race reported by Hutton (1867, 189) in May “‘about 300
miles north of the Crozet Islands.”’
In default of exact information about the life history of the subspecies
elegans, the following notes on the typical race by Falla (1934, 253) may prove
of value:
The wing-beats of this shearwater are very “‘rigid’’ in quiet air.
The protoptyle down of the chicks is light gray, the throat, breast and
abdomen white, the mesoptyle dark gray above and below. Fledglings are
not distinguishable from adults except by the immature bill characters. Re-
684 OCEANIC BIRDS OF SOUTH AMERICA
mains of small cephalopods and minute crustaceans have been found in their
stomachs.
It is the first petrel to lay its eggs of all the species nesting on islands off
northern New Zealand. A freshly moulted pair of adults has been found in a
burrow, during the daytime, on April 17. On October 5, at Mokohinau Islets,
a colony was found to be abandoned except for two belated chicks. Adults in
worn plumage and young in fresh plumage have been collected at sea in mid-
November. Present-day observations indicate that this shearwater is a winter
breeder only, with a season from April till October, although some of the
earlier observations are hard to reconcile with this.
AUDUBON’S SHEARWATER
Puffinus lherminieri lherminieri
Puffinus (sic) Lherminieri Lesson, 1839, Rev. Zodl., 2, p. 102 (‘Ad ripas Antillarum’’).
Names: In the English-speaking Antilles and in Bermuda this shearwater is known as the
Pimlico, sometimes spelled Pimblico or Pemblyco. Common synonyms of the specific name are
obscurus, auduboni, and minor; assimilis also often pertains to this species.
Characters (sexes alike): Upper surface blackish brown, almost black on the outer webs of
the wing quills, and the primary coverts; concealed inner webs of wing quills much paler; lower
half of lores white, the line of demarcation between dorsal and ventral plumage being mottled
under and behind the eye, and along the cheeks and sides of neck, through a variable mingling of
the dark and white feathers; a faint white stripe on the lower eyelid; flanks splashed with sooty
or grayish brown, which appears variously as splotches, mottlings, or shaft-streaking on otherwise
white feathers; at the sides of chest this dark color sometimes extends slightly toward the mid-line,
the dark feathers in this region being mostly narrowly edged with whitish; ventral surface, from
chin to crissum, including the axillaries, and the wing-lining except along its anterior border,
white; lower aspect of wing and tail quills dark neutral gray, when fresh; longest under tail coverts
blackish brown, the shorter coverts dark mouse-gray and white, some being one or the other, some
@arti-colored. Iris brown; bill black, bluish on the mandible and toward the base of culminicorn;
feet and legs flesh color, with the outer toe and outer side of tarsus blackish.
26 adults of both sexes from various West Indian islands, the Bahamas, Bermuda, and the south-
eastern United States: wing, 200-216 (208.2); tail, 82-94 (87.2); exposed culmen, 26-32 (29.8);
depth of closed bill at base, 9-10.8; least depth of bill, 6-7.5; width of bill at base, 10-13; tarsus,
39-43 (40.3); middle toe and claw, 43.5-48 (45.8) mm.
Half-grown downy chicks are of a fairly uniform dusky gray color above, whitish on the
ventral surface.
Egg: White, fragile and not highly polished. The measurements of 39 average 52.5 x 36.2 mm.,
the eggs showing the four extremes measure 57.3 x 40.8, 49.2 x 35.2 and 50 x 34 mm. (Bent;
1922, 74).
Distribution: Breeds at Bermuda, the Bahamas, and many islands of the West Indies, particu-
larly among the Lesser Antilles. Islets off Barbados, Grenada, and Tobago seem to be the closest
breeding stations to the South American continent. The known range extends from the coast of
British Guiana northward to about latitude 37° N., on the east coast of North America, and casually
«as far as Long Island, New York.
Audubon’s Shearwater is or was an abundant bird at islands around the
Caribbean Sea. During the course of the Brewster-Sanford Expedition, Beck
observed numbers of these petrels feeding along the route of his passage from
island to island of the Lesser Antilles in April. In July, 1916, he saw others not
far from Trinidad, and at the end of the same month obtained several from their
AUDUBON’S SHEARWATER 685
burrows on an islet off Barbados. In the American Museum Collection there is
an example from still farther southward, namely a male taken by Mr. Arthur
Carlin about 160 kilometers off the coast of British Guiana, on December 2, 1931.
Southward beyond this point the distribution of Audubon’s Shearwater
passes into the realm of conjecture. It is, however, worth noting for the sake
of subsequent determination that when Shackleton’s last antarctic expedition
touched at St. Paul Rocks, in the central part of the equatorial Atlantic, during
the month of November, Wilkins (1923, 476) wrote, ‘‘From the appearance of
some open holes under the rocks members of the petrel family may also breed
there.’’ Furthermore, I have already related in the account of the island of St.
Helena that subfossil remains of a small shearwater have been found at this
South Atlantic island, and that they have been listed as pertaining to the present
species. Puffinus lherminieri has representative races in the Indian Ocean and the
South Pacific, but it is, of course, impossible to infer what the extinct shear-
waters of St. Helena may have been until the matter has been investigated
further.
Audubon’'s Shearwater is the typical form of the group characterized by a
““brown-black”’ upper surface and other features listed in the key. The material
examined includes an excellent series in the American Museum of Natural His-
tory, as well as the type skin of P. auduboni Finsch, in the Berlin Museum, and
other specimens in foreign collections. Localities represented by the measured
skins comprise Barbados, Guadeloupe, St. Thomas, Florida, the Bahamas,
Bermuda, Cobbs Island, Va., and Bellport, N. Y.
Downy young, in various stages of growth, are well represented in the
American Museum Collection by birds taken at the Bahamas, St. Thomas, and
Guadeloupe during the month of May. The down gives place to a plumage of
the adult type, the dorsal surface being of a nearly uniform hue, close to blackish
brown or fuscous black, without white feather margins except at the sides of
the breast.
The lores in this subspecies are mostly dark, with no more than a narrow
line of white from the bill to the angle of the mouth. The inner vanes of the
primaries, as in all forms of the species, lack white; the lower tail coverts are
mixed but prevailingly dark, and the axillaries and under coverts of the wing
are rarely if ever without at least a few dark splotches.
Diminution in the numbers of Audubon’s Shearwaters throughout much of
the range is in part explained by the fact that the young are collected as food
at many nesting grounds. Formerly, at any rate, dried and salted adults, and
young birds in the down, were offered for sale in public markets of the West
Indies. At Grenada they were called “‘Diablotins,’’ the same name by which
Pterodroma hasitata was known in the French islands of the Lesser Antilles. The
natives of Greenville, Grenada, reported that the birds sold there were taken
by fishermen from holes in an islet called Mouchoir Quarré (Lawrence, 1889, 19).
The nests of this shearwater are either tunneled through soil or placed in
natural rock cavities, according to circumstance. At Bermuda and the Bahamas,
‘for example, they occupy natural holes in the coral limestone, while at Little
686 OCEANIC BIRDS OF SOUTH AMERICA
Saba Islet, off St. Thomas, Beck found burrows in the earth under dry grass near
the top of the island.
In common with many other pan-tropical sea birds, Audubon’s Shearwater
has developed a prolonged nesting season, as the following records will indicate.
These also contain possible evidence that the petrels may resort to their hidden
nest-chambers even after the young birds have flown.
Lowe (1911, 222) obtained eggs of this shearwater from Barbados in March.
They came presumably from the only known local breeding station, a mushroom
rock a hundred meters off the northern coast of the island. Beck persuaded a
black man to swim to this rock on July 26, 1916, as noted above, and thus
acquired four adult birds from their burrows. Feilden (1889, 66 and 503) found
heavily incubated eggs and well-grown young on the same islet in March, and
adults again in the holes during October. He states that for more than two
centuries the islet, which is only about 20 meters in diameter by 10 to 12 in
altitude, has been a locally famous breeding ground of the species.
Continuing the scattered jottings relating to breeding season, we may note
that on March 4 and 11, Bradlee (1906, 217) found Bermuda Audubon’s Shear-
waters incubating their eggs, while in May, at the same locality, Plath (1914,
558) observed half-grown chicks. At Ship Channel Cay, in the Bahamas, Bryant
(1859, 132) discovered many adults covering eggs on March 24, and at Washer-
woman Cay both eggs and newly hatched chicks were in evidence during early
May (Bonhote, 1903, 315). The latter condition also represented the status of
the species at Labaye Rock, off Grenada, as early as April 2, 1888 (Lawrence,
1889, 19). At Little Saba Island, south of the western end of St. Thomas, Virgin
Islands, Beck found chicks practically ready for flight on May 9, 1917, and also
two adults in a burrow on August 21, 1916. The latter specimens, like the July
adults from Barbados, had begun to moult, a process which seems to go on
throughout the remainder of the northern-hemisphere summer.
At Little Saba, in late August, Beck observed numbers of partly completed
burrows, the proper owners of which were absent during the daylight hours.
From this, in conjunction with the foregoing dated notes, we may infer that—
if breeding is not absolutely continuous and seasonless—the sequence is some-
what as follows: courtship and nest-construction, July to November; eggs,
January or February to May; hatching of young, May to July. The data are
highly fragmentary, and continuous observation is much needed before the life
history can be satisfactorily outlined.
The following account is based upon the tena of C. W. Townsend (in
Bent, 1922, 74), and of some of the ornithologists already cited in the biography
of this species.
Whether the Audubon’s Shearwaters are breeding in soft soil or among
crevices of rock, the nest-chamber is usually within half a meter of the surface.
The egg is sometimes laid on bare earth or stone and sometimes in a rudimentary
nest loosely constructed of dried grass or small twigs. As among most other
petrels, incubation is shared by the two parents, which are usually to be found
together in the compartment during a period preceding the appearance of the
AUDUBON’S SHEARWATER 687
egg. For a few days after hatching, one adult remains with the chick, not cover-
ing it but merely sitting beside it. Thereafter it is left alone during the hours
of daylight.
At their breeding grounds these petrels are very active during the night, but
are rarely seen or heard at any other time. They enter and depart from their
burrows only between dark and dawn. All night long during the courtship
season their mournful cries, some of which are said to resemble catcalls, ring
out in the free air or come as a muffled clamor from the depths of the tunnels.
The nestling shearwaters utter a liquid chirping or peeping note. Brooding
birds taken from nests on an island near Grenada remained quiet in captivity
throughout the day, and took no food. At night, however, they fed willingly
on scraps of fish, all the while scuffling about and uttering low howling notes.
Members of a community which have been relieved of the tasks of incubation
and brooding remain at sea throughout the day, generally at a distance at least
great enough for them to be out of sight of their home islet. They often rest
for hours on the surface of the ocean in extensive flocks or ‘‘rafts’’ of birds, and
have been seen in Bahaman waters, during April, mingled with large numbers
of floating boobies and terns (Bryant, 1859, 132). Although ordinarily credited
with being shy at sea, the Audubon’s Shearwaters sometimes gather and
scramble for food about the boats of West Indian fishermen.
Bent (1922, 75.) quotes Audubon’s classic description of these shearwaters,
written as the great pioneer ornithologist was lucky enough to see the birds at
close range, skimming over patches of gulf weed, near the southern tip of
Florida. They would
. flap their wings six or seven times in succession and then sail for three or four seconds with
great ease, having their tail much spread and their long wings extended at right angles with the
body. On approaching a mass of weeds, they raise their wings obliquely, drop their legs and feet,
run as it were on the water, and at length alight in the sea, where they swim with as much ease
as ducks, and dive freely, at times passing several feet under the surface in pursuit of fishes, which,
on perceiving their enemy, swim off but are frequently seized with great agility. Four or five,
sometimes fifteen or twenty, of these birds will thus alight, and during their stay about the weeds,
dive, flutter, and swim with all the gaiety of a flock of ducks, newly alighted ina pond. . . . At
times, as if by way of resting themselves, they alighted, swam lightly, and dipped their bills
frequently in the water, in the manner of mergansers.
GALAPAGOS SHEARWATER
Puffinus lherminieri subalaris
Puffinus subalaris Ridgway, 1897, Proc. U. S. Nat. Mus., 19, p. 650 (Chatham Island, Galapagos).
Names: This race has been listed under the same specific names as the preceding form, besides
which deck? is a subspecific synonym.
Characters: Resembling P. lherminieri [herminiert, but more heavily marked with dark feathers
along the flanks, and without dark areas descending from the back onto the sides of the chest;
furthermore, the tail in the Galapagos race is both relatively and absolutely shorter. An additional
and curious feature, which appears to distinguish subalaris from every other form of the species, is
that the nasal tubes are exceptionally firm and corneous, showing almost no trace of shrinkage in
dried skins.
10 adults of both sexes: wing, 189-203 (194.8); tail, 68-75 (71.8); exposed culmen, 24.7-29
688 OCEANIC BIRDS. OF SOUTH AMERICA
(27.7); depth of closed bill at base, 9-10; least depth of bill, 6-6.5; width of bill at base, 10.5-12;
tarsus, 34-37 (36); middle toe and claw, 40-43.6 (41.3) mm.
Loomis (1918, 123) based a study of this race upon 104 adult examples, numerous chicks, and
eggs. His measurements, which agree with those given above, show that the sexes exhibit no
difference in size. The average length in the flesh of 5 males amounted to 296 mm.; that of 18
females to 299 mm. In wing-expanse one male measured 625 mm., one female 630 mm. The flesh
colors agree with those of the typical race.
Among a number of downy nestlings the youngest is deep mouse-gray with grayish white
patches on the abdomen and chest.
Eggs: Three from Hood Island are dead white, in form inclining toward elliptical-ovate, and
measure 47.1 x 32.9 and 48.5 x 33.8 mm. (Loomis, 1918, 129).
Distribution: Confined to the Galapagos Archipelago; breeding at Hood, Indefatigable, and
Wenman Islands, and probably at many of the other islands and their outlying rocks.
Loomis has given an excellent account of this subspecies, based upon collec-
tions and observations of Gifford and others made during the Galapagos Expe-
dition of the California Academy of Sciences.
Perhaps the shearwaters of the Galapagos colonies do not wander far from
their breeding grounds. Members of the California Academy Expedition, at
any rate, saw them only within an area of ocean bounded by latitudes 5° 30’ N.
and 2° 29’ S. However, the notes and chart of Jespersen (1933, 197) at least
suggest that these birds may migrate or stray well to westward in the tropical
Pacific, and Wetmore (1923, 171) records a specimen taken in December on the
west coast steamship lane south of Panama. The problem is one which only
future pelagic collecting can solve.
Loomis (1918, 123) writes of the habits of these birds at the Galapagos:
Throughout the archipelago they were very common, haunting alike the sheltered bays and
coves and the open sea. They probably breed on most of the islands, although eggs or downy
young have been reported from only three. The Expedition found at Hood Island a fresh egg and
a nestling on September 28, a nestling on October 2, fresh and incubated eggs on February 1, fresh
eggs on February 6, and nestlings on June 25. Moreover, two birds were seen to enter holes in a
cliff on Champion Island in February and one was noted ina hole in a cliff on Indefatigable Island
in July. Messrs. Snodgrass and Heller record a single egg taken in December on Wenman Island
and Lord Rothschild and Dr. Hartert state that downy young were found on the same island in
February and a great many eggs on Culpepper Island in July. It appears, therefore, that relays
protract the breeding season, with the laggards causing it to cover most, if not all, of the year.
Perhaps there are two distinct breeding seasons, some birds laying in winter, others in summer.
At Hood Island, quoting in substance from Mr. Gifford’s notes, they nested in small tunnel-like
holes in the lava sea cliffs. The lowest holes were near the water and were damp, and the highest
were sixty or seventy feet above it. As in some other petrels, the male and female become tenants
before the laying of the single egg, which is placed at the farther end of the hole, usually on the
bare soil or rock, sometimes within arm's reach of the entrance.
These shearwaters are generally silent. However, on two occasions in January small flocks
were flying about the cliffs at Academy Bay, Indefatigable Island, making a twittering sound. One
evening near Essex Point, Albemarle Island, a flock of about a hundred was fishing. There was
great excitement among them. Rushing madly about, they kept up a continual twittering. Twice
at Hood Island, birds in their nesting holes were heard uttering notes somewhat resembling the
mew of a kitten. In each instance the hole was tenanted by a pair of birds. These mewing notes,
of one or two short shrill notes, were sometimes uttered when the collector’s hand was thrust
into the hole, which intrusion was always resented, a spirited defense being made with bill and
claws. They showed a disposition to bully other birds. One was seen pursuing a Turnstone and
several pestered a Brown Pelican until he retreated to a cliff to escape from the annoyance.
GALAPAGOS SHEARWATER 689
Like some others of their tribe, they were sociably inclined, frequently flying about the cliffs
and rocks in small compact companies or congregating on the water or winging their way at
times over its surface in loose flocks and straggling columns. When fishing, a community of
interests was often formed with other species, particularly the Noddy and boobies.
The flight is usually low and somewhat undulatory, ascendant during the rapid wing strokes
@which vary from four or five to eight or ten) and descendant during the short sail. In rough
weather they rise higher and prolong the sailing flight, but do not attain to the ‘beautiful evolu-
tions’’ of the Dark-rumped Petrel. In rising from a calm sea, they extend their wings and paddle
rapidly forward for about two feet when they clear the water and are fairly a-wing. When feeding
in windy weather, they often alight for a moment without closing their wings. One proved him-
self well worthy of the name of petrel while picking up food during a brisk wind. He would poise
for a moment, with wings outspread and feet just touching the water, and then dart to the wind-
ward for a few feet without flapping his wings, which apparently served the same purpose as “‘the
sails of a vessel when close-hauled on the wind.’’ On another occasion a flock of about thirty
while feeding would fly slowly to the windward for a few rods, keeping close to the water, and
then turn and fly swiftly back to the starting point and repeat the maneuver. In calm weather
they collected in flocks on the water while feeding. On one occasion the birds of a company were
continually putting their heads under water and when something edible was discovered they would
dive, often remaining beneath the surface for a full minute.
The remains of small crustaceans were found in the stomachs of several birds taken from nesting
holes on Hood Island in February. One day a number were flying about a brigantine at Villamil,
Albemarle Island, apparently attracted by the droppings from the cattle that were being hoisted
aboard.
GREAT-WINGED PETREL
Pterodroma macroptera macroptera
Procellaria macroptera A. Smith, 1840, Illustr. Zodl. So. Africa, pt. 2, pl. 52 (seas off Cape of Good Hope).
Names: Gray-faced Petrel, Cape Parson, Mutton Bird; Black Eaglet at Tristan da Cunha.
Synonyms of the specific name include fuliginosa, atlantica, pacifica, and gouldi. The last has a
correct subspecific application.
Characters: A long-winged black petrel, with a gray throat.
Adults (sexes alike): General color sooty black, slightly paler and grayer about the base of
the bill and on the throat; in the latter region the whitish bases of the feathers often become con-
spicuous through wear, producing a mottled whitish patch; quills of wing and tail black, the pri-
maries ashy at the base of the inner web where the shafts also tend to become whitish. Iris brown,
bill and feet black.
One male, and one of unknown sex, South Atlantic: wing, 302, 309; tail, 108.4, 123; exposed
culmen, 35, 35.2; width of bill at base, 15.8, 16; length of maxillary unguis, 21.3, 21.4; tarsus,
41.8, 43; middle toe and claw, 56.7, 57.3 mm.
The length in the flesh and wing-expanse of the male were, respectively, 41 and 106 cm.
4 males of Pterodroma macroptera gouldi, from New Zealand: wing, 311-323 (319); tail, 121.5-
132.1 (125.4); exposed culmen, 36.2-37.4 (36.9); width of bill at base, 16.1-16.8 (16.5); length of
maxillary unguis, 23.2-24.5 (24); tarsus, 42.9-44.5 (43.6); middle toe and claw, 60.2-63.7 (61.7) mm.
Young from New Zealand are clad in sooty gray down, the juvenal plumage being indistin-
guishable from that of adults.
The eggs, according to Mathews (1932, 32), are white and smooth, without gloss; 6 from
Tristan da Cunha average 68.8 x 48.2 mm., the largest measuring 69 x 49 mm.
Distribution: The species is circumpolar in sub-antarctic seas, and is said to breed as far south-
ward as Kerguelen Island, as well as at the Crozets, Tristan da Cunha, and islands in the New
Zealand region. The subspecies sacroptera nests at Tristan, and is likely to prove peculiar to that group.
This petrel, which wears a black robe and has a more or less gray face, is
said to have been called the “‘Cape Parson’’ by the old-time British sailors.
690 OCEANIC BIRDS OF SOUTH AMERICA
Judging by the limited material I have seen, however, the typical South Atlantic
race—presumably the form to be seen off the Cape of Good Hope—is distinctly
less “‘gray-faced’’ than the larger subspecies of New Zealand waters, which
has been named Pterodroma macroptera gouldi. | know nothing about the status
of the birds said to breed at high-latitude islands of the Indian Ocean. These
may possibly be as gray-faced as New Zealand examples.
Godman (1908, 177) points out differences between South Atlantic birds and
those from the New Zealand region, even though he was disinclined to attach
any importance to the distinctions. He quotes Gould and Hutton to the effect
that the form occurring in Tasmanian seas differs from that of the Atlantic in
its larger size, longer wings, and grayer face. Godman’s plate, moreover, is an
excellent representation of the Atlantic bird, and differs markedly from the gray-
faced form of New Zealand.
In all of this I concur. Our New Zealand specimens are larger, and have a
pronouncedly longer maxillary unguis, than South Atlantic birds. The bills of
even New Zealand fledglings are bigger than those of Atlantic adults. Further-
more, young birds from Cuvier Island, New Zealand, which are just shedding
their down, have gray faces like those of their elders, but quite different from
those of Atlantic birds.
Observers agree that the Great-winged Petrel is a handsome, dashing bird.
Hutton (1865, 286) remarks that on the wing it resembles a gigantic swift. I
believe that I saw it frequently during my cruise in the brig ‘Daisy,’ particularly
in March, 1913, along the 30th meridian of west longitude, and between lati-
tudes 33° and 43° S. At the time, however, I made the entries doubtfully in my
journal because I was unable to collect a specimen, and because I had not yet
become acquainted with the black phase of Prerodroma arminjoniana, a similar
though smaller bird. The latter began to appear during our northward voyage
in latitude 25° S., four days’ sail to southward of South Trinidad.
The Museum collection possesses only two specimens of the Great-winged
Petrel from the South Atlantic. One, a male, was taken by the Cleveland
Museum Expedition in latitude 27° 50’ S., longitude 8° 26’ W., on August 27,
1925. The second is an unsexed bird collected by P. C. Keytel at Tristan da
Cunha. Both of these look alike, and are of different appearance from our
excellent series taken in the New Zealand region by the Whitney South Sea
Expedition. The Atlantic birds seem smaller, with slenderer bills and without
the distinct gray face. In color they are entirely sooty black except for a slightly
grayer area around the base of the bill, including the forehead, lores, chin, and
the fore part of the throat. In one the center of the throat shows more or less
whitish mottling through exposure of the concealed parts of the feathers, which
are whitish here and grayish over most of the rest of the body. The ventral
surface seems to be as dark as the back, except that it becomes more rapidly
dulled through wear, with the accompanying appearance of a faintly rufescent
tinge on the margins of the feathers. Among our New Zealand specimens the
gray mask is uniformly pronounced, the bills are heavier, and the maxillary
unguis notably larger.
GREAT-WINGED PETREL 691
The records of Hutton (1867, 187), Dabbene (1923, 33), and others indicate
that this sub-antarctic petrel is likely to be met with close to the 30th parallel
in the southern oceans, from where it ranges southward to about latitude 50° S.
It has never been recorded from the Falkland Islands, but it is reported to breed
at Kerguelen, which is far more glacial than the Falklands, and lies on the con-
vergence with the Antarctic Zone of surface water. The representatives of the
species at Kerguelen are likely to prove at least racially different from those at
Tristan da Cunha, the South Atlantic breeding ground, which is close to the
Sub-Tropical Convergence. The species is not yet known from Gough Island,
but I confidently expect it to be found there, too.
According to Barrow (1910, 275), the ‘‘Black Eaglet’’—possibly a corruption
of ‘‘haglet,"’ a common seafarers’ name for various petrels—reaches its egg-
laying state at Tristan da Cunha about the first week in July. The season is far
in advance of the springtime period of November and December, when so many
of the resident Procellariiformes nest. Furthermore, Mrs. Barrow’'s additional
notes seem somewhat confused, for she speaks of obtaining eggs of the Black
Eaglets during both May and October. It may be, however, that the notes of
Falla, which are summarized below, resolve all these difficulties. The zonal
position of Tristan is very nearly the same as that of northern New Zealand,
and at each of these localities the Great-winged Petrel becomes a bird of almost
sub-tropical range, and hence may well have freed itself from the rhythm of a
rigidly fixed breeding season. At Kerguelen Island, the life history would
exhibit the usual type of calendar contro], but at Tristan, as in New Zealand,
there would be nothing surprising about a prolonged nesting period, with birds
in residence practically throughout the year.
The ‘Challenger’ naturalists found Great-winged Petrels in their burrows at
Nightingale Island during October, and Campbell (1877, 67) states that the
slope of this island, at an altitude of 300 meters or more, was so honeycombed
with their holes that the explorers sank up to their knees through the soil at
every other step. Such high concentration of the burrows agrees with the report
of Littler (1910, 173) from Little Barrier Island, New Zealand.
All exact data on the nesting habits of the Great-winged Petrel come from
other parts of the world than the South Atlantic. Studer (1879, 109) states, for
example, that egg-laying begins at Kerguelen about the first of November and
that young birds appear in December. Far more detailed, however, are the recent
admirable studies of Falla (1934, 25), from which the following account is drawn.
In northern New Zealand this petrel breeds at every island where burrows
can be made, and it is equally at home along suitably inaccessible cliffs on the
mainland. It is not strictly a colony-forming bird, as are so many of the shear-
waters, but its abundance at any locality is due rather to the presence of soil
adapted to a dense accumulation of individual families. Isolated single burrows
are not infrequently found far inland.
The breeding season is about as long as would be possible in a temperate
region. Within a month after the departure of the last youngsters from the
burrows, a few adults can be found occupying them sporadically during Feb-
692 OCEANIC BIRDS OF SOUTH AMERICA
ruary and March. Such early arrivals come singly to the breeding ground, and
in most instances they prove to be male birds. Between April and June mated
pairs can be found together in increasing numbers, such birds often remaining
in their nests throughout the day. The burrow is seldom much more than a
meter in length, and the carrying-in of vegetable matter for nest material is a
sign of imminent egg-laying, which takes place during July and early August,
the first chicks hatching before the end of the latter month. The youngsters
reach their maximum size, and begin to put forth feathers, in late October. Dur-
ing November, which is the “‘mutton bird season’ for this species, the young
are still taken more or less regularly for food by the North Island Maoris.
Half-fledged young weigh up to 624 grams, or fully 100 grams more than the
adult birds, but this becomes reduced to less than adult weight before they fly.
Frosted edges on the feathers of the mantle are noticeable in the fresh plumage of
the young, as in the case of most dark petrels. By early January the chicks are
full-fledged, and before the end of that month they all depart.
The courtship of this petrel has never been described. Pairs of birds seem to
spend several days and nights continuously in a burrow, after which they may
pass a similar period at sea. When the birds first appear in the coastal waters,
particularly during May, they are often seen in pairs. Both sexes incubate, but
Falla has found only males on the egg during the later stages of incubation, at
any rate during the daytime. Males have likewise been found constantly in
attendance upon the chick up to the time that the latter is ten days old, after
which age it is visited only at night. Fledglings not infrequently come out of
their burrows after dark to amble about in the free air, returning underground
before daylight.
Littler (1910, 173) says that the call of this petrel, heard along the cliffs
after sunset, is a melancholy ohi-ohi. The young make a whimpering noise
while being fed.
The Great-winged Petrel has an extraordinarily extensive feeding range, and
its subsistence appears to be quite independent of food in the coastal waters
close to its nesting ground. Falla, indeed, states that it is rarely seen within
80 kilometers of the shore during the hours of daylight, and that its almost
exclusive diet consists of pelagic cephalopods. Beaks, crystalline lenses, and
sepia of the latter animals are constantly found in the stomachs of both young
and old birds, and such material is often regurgitated when these petrels are
disturbed.
BLACK-CAPPED PETREL
Pterodroma hasitata
Procellaria hasitata Kuhl, 1820, Beitr. Vergl. Anat., Abth. 1, p. 142 (no locality given = Dominica).
? Pterodroma caribbaea Carte, 1866, Proc. Zodl. Soc. London, p. 93, pl. 10 (Blue Mountains, Jamaica).
Names: West Indian Petrel; ‘‘Diablotin.'’ Synonyms of the specific name include diabolica,
meridtonalis, and rubritarsi. If the black petrel of Jamaica is of the same species, the names caribbaea
and jamaicensis are to be included among the synonyms.
Characters: Commonly known as a white-breasted, brown-backed petrel, with whitish fore-
head, nape, and rump, but probably having also grayish or blackish phases represented by the
so-called Jamaican Petrel.
DLA CK-CAPPED: PET REL 693
Adults, black-capped phase (sexes alike): Dorsal coloration generally dark brown, the feathers
with obsolescent margins of lighter brown, the longer scapulars and upper wing coverts rather
blacker than the back, with scarcely perceptible paler brown edges; quills black, the primaries
ashy brown on the inner webs, with the bases inclining toward whitish, the inner secondaries
rather browner; rump and basal upper tail coverts black; lateral upper tail coverts at the base of
the tail, and all the long coverts of this series, white; tail feathers black, white at the base, espe-
cially on the inner web; crown of head black, forming a cap; forehead and lores white, the center
of the former black, mottled with white edges to the feathers; sides of face white, the feathers in
front of the eye black, and spotted with black below the latter; cheeks and sides of neck pure white,
extending in a broad white collar round the hind neck, which has a few brown-tipped feathers *
in the center; entire under surface of body white, including the under tail coverts; under wing
coverts black, forming a broad band round the whole of the bend of the wing, the median and
greater coverts and axillaries white; under surface of the quills black, gray on their inner webs,
which have white bases. Iris brown; bill black; legs and feet parti-colored (flesh and black) in
the usual petrel manner.
Adults (‘‘P. caribbaea’’): General color dark; dorsal surface sooty brown with a gray gloss
caused by a dark slaty margin to the feathers; the longer scapulars, wing coverts, and secondaries
sooty brown, with a faint edging of gray on the secondaries and greater wing coverts; primaries
black, with a slight shading of gray, the inner webs for the most part ashy brown; upper tail
coverts light ashy gray, with white bases, the center ones blackish, forming a patch, the longer
coverts white, with an ashy tinge; tail feathers blackish brown; crown of head like the back, but
slightly darker, with a shade of gray on the forehead and sides of face; under surface of body entirely
dull ashy brown, the chin and upper throat decidedly gray; abdomen and under tail coverts hoary
gray, the longer ones with dusky tips; under wing coverts blackish brown, with a slight gray
shade; quills blackish below, ashy gray on the inner webs, and on the lower surface of the secon-
daries. Bill and feet entirely black.
Following is a list of the six specimens in the American Museum of Natural History, and of
their measurements:
1. AMNH 98754, sex?, Cayuga County, N. Y., September, 1893.
Sanford 3971, &, Cincinnati, Ohio, October 6, 1898.
AMNH 111211, &, Central Park, New York City, January 8, 1912.
AMNH 6212, sex?, Florida (type of Procellaria meridionalis).
Uncatalogued fragments, Quogue, N. Y., July, 1850.
. “‘Pterodroma caribbaea’’ Brewster-Sanford 5185, o, Jamaica, 1879.
The measurements are in the same order, the seventh representing a specimen in the Berlin
Museum.
AYRE N
Wing Tail Culmen ba ee ae Tarsus arent
its 286 131 34.5 15.4 38 55.8 mm.
2s 294 121 31.1 13.4 35.5 51.1
35 280 118 31.3 14.5 38.3 52.5
4. 290 126.5 14.2 37
5. 35:2 14.5 36.6 53:2
6. 275 120.2 30 14.8 36 50.3
7. 295 124 34.5 37 56
The example of *' Prerodroma caribbaea’’ (No. 6) is of the same proportions as the others, and has
an exactly similar white spot above the tail. The bases of the rectrices are also white as in the
white-breasted birds.
Distribution: Bred formerly in the mountains of Guadeloupe (both white-breasted and dark
birds), Dominica, and Martinique, Lesser Antilles; probably still a rare resident of Dominica,
and perhaps also of Hispaniola. If caribbaea is actually a synonym of hasitata, Jamaica and doubtless
694 OCEANIC BIRDS OF SOUTH AMERICA
other islands of the Greater Antilles were part of the original breeding area. At sea the range
covers the Caribbean region and the western pan-tropical Atlantic Ocean between eastern Brazil
and the coast of the United States.
That the Black-capped Petrel was not collected during the course of the
Brewster-Sanford Expedition is due to no lack of effort on the part of Mr. Beck,
as I shall record below. The species is still in existence and has been identified
in the field by competent observers many times during the last twenty years.
Not long since, Bond (1928, 526) warned against placing too much credence in
the commonly accepted story of the complete extirpation of this petrel at
Dominica. He called attention to the facts that large areas of the mountain
known as Morne Diablotin were still unexplored, and that the mongoose,
charged with the wiping out of certain West Indian birds, had, fortunately,
never been introduced into the island. Proof that the Black-capped Petrel is,
indeed, not extinct in the Lesser Antillean region, and that it almost certainly
still breeds at Dominica, has since been forthcoming through the capture of an
adult female at Roseau on May 2, 1932, as recorded by Hobley (1932, 17), who
has published three excellent photographs of the living bird. Wetmore and
Swales (1931, 63) have noted the capture of a specimen at Moca, an inland
locality in Haiti, on May 15, 1928. In another paper, Wetmore (1932, 107)
states that no less than four examples were taken and fully a hundred observed,
on this occasion.
Notice of other slightly less up-to-date records of the Black-capped Petrel is
given by Wetmore (1927, 276), who himself observed a number of the birds along
the steamship course between New York and Rio de Janeiro, at a point southeast
of Bermuda, during early June, 1920. Unlike the smaller petrels, he states, the
Black-caps paid no attention to the wake of the vessel, although at times they
approached within a distance of 10 meters before veering far out to one side.
Their gliding flight was near the water, with frequent changes of course. Those
seen at close range showed the dark crown, with a white line behind it, the more
or less grayish cast to the back, the white rump, and a dusky tinge along the
sides. The lower surface of the wings was white, outlined in black, with the
dark margin heavier in front. It was in approximately these same latitudes that
Nichols (1913, 505) observed a Black-capped Petrel at the opposite season of the
year, namely on January 25. He states that the flight and appearance of the bird
reminded him of the Greater Shearwater (Pwffinus gravis), from which the Black-
capped Petrel can readily be distinguished by the large patch of white above
the tail.
Wetmore, in the paper cited above, indicates that the reduction in a former
more extensive breeding range of the Black-capped Petrel evidently began at an
early date, because he had identified as probably pertaining to this species a bone
from an Indian kitchen midden at the island of St. Thomas.
During the West Indian work of the Brewster-Sanford Expedition, Beck
hunted for the breeding grounds of the Black-capped Petrel in late April, 1917.
They are known to have been abundant at Dominica as late as the year 1858,
coming from sea each year in October (Lawrence, 1878, 68). A native guide,
BLACK-CAPPED- PETREL 695
whose parents had dug the birds out of their holes in the forest a half century
before, accompanied Beck, and together they combed over the ground on the
steep ridge below the crest of Morne Diablotin. They also spent the whole of
one night and parts of others in the woodland, listening for calls of the birds,
but without result. The only warm-blooded animal found in burrows of the
forest floor, or in undermined recesses among the roots of trees on steep slopes,
was an unidentified, rat-like mammal, which may possibly represent the species
of opossum which, according to Nicoll (1904, 563), was introduced from
Grenada or Tobago into Dominica some time since the latter part of the seven-
teenth century. Nicoll infers that this animal may well have wiped out most
of the petrels at their nesting sites.
A generation ago, Ober (1881, 41) also scaled the precipitous sides of Morne
Diablotin in vain, investigating traces of the petrels’ burrows at a date when
many natives asserted that they well remembered the bird. Other unproductive
searches are referred to by Godman (1908, 185).
Most of our information relating to the life history of the Black-capped
Petrel is from the ancient report of Pére Labat (1724, 1, pt.2, 109). We learn
from him that the Diablotins nested high on the mountains, perhaps altogether
on volcanic ridges above the zone of dense forests. There the birds burrowed
in the earth like rabbits, and remained concealed throughout the hours of day-
light in the customary petrel manner. Labat says that the Diablotins are goggle-
eyed birds which can neither stand the light nor discern objects in it. They are,
therefore, clumsy and helpless when pulled forth from the burrows. Yet such
observations take no account of the obvious ability of these birds to fly about
over the sea during the day; it is probably the sudden change from darkness to
light which discommodes their eyes. At night in the mountains they could be
heard crying continuously, as though calling and answering one another with
mournful voices while in flight. The annual mating season began after the end
of September, and eggs were probably laid during January, for the young were
hatched by March. These were covered with thick yellow down, and were
known to the blacks of the islands as ‘‘cottons.’’ By the end of May the fledg-
lings made their way to sea, and thereafter no Diablotins were seen in the neigh-
borhood of the nesting grounds until the following September.
As recently as 1914, Noble (1916, 372) found an aged negro living on the
slope of the Soufriére of Guadeloupe who had, in his youth, joined parties on
the Nez Cassé to take the birds from their burrows. He stated that these petrels
had formerly bred on the northern and northeastern slopes, but that none of
them had been seen at Guadeloupe since the earthquake of 1847. They used to
arrive in late September, to breed nearer the close of the year, the young re-
maining in the nests until March.
Labat’s account is accompanied by an illustration of the ‘‘Montagne des
Diables,’’ showing negroes at work with their bird-poles in the treeless Sou-
friére of Guadeloupe. He states that in spite of the fatigues of the hunt, his
curiosity led him to take part in one which lasted for more than 24 hours. The
party followed the bed of a running stream inland as far as was possible, then
696 OCEANIC BIRDS OF SOUTH AMERICA
climbed the steep slopes of the mountain and camped for the night. Next morn-
ing the burrows were searched out, the occupied homes being determined
through the aid of dogs with well-trained noses. The birds, for the most part,
were dragged out by being teased into seizing with their bills the end of a pole
thrust into the burrows. Before noon of the second day, the party of six men
had captured 213 petrels, with which they returned to thé coast. ‘‘One has to
admit,’ writes Pére Labat, ‘‘that a Diable right from the spit is a delicacy.
I had thought that one bird would well satisfy my appetite but, whether it
was due to the cold mountain air, the strenuous trip, or to the fact that the
Diables of this island are more tempting and digestible than those of other
regions, I felt constrained to do as my companions did and to eat a second.”
Pére Labat evidently had the instinct of a conservationist, for he wrote in
his notes for the year 1696 that the reprehensible habits of the French settlers
had nearly wiped out the Diablotins in the accessible regions of Guadeloupe.
This, however, did not prevent him from recording that the birds are a sort
of manna which God had sent the inhabitants of the island for an annual period
of gourmandising. The ‘‘cottons’’ he describes as particularly tasty, and he
gives detailed recipes for cooking both these and adult birds in several different
ways.
The question has arisen many times as to the relationship of the Diablotin
to the black petrel or “Blue Mountain Duck”’ (Pterodroma caribbaea) of Jamaica.
It has been pointed out by Loomis (1918, 57) and others that hasitata and
caribbaea may represent dichromatic phases of the same species, a condition
familiar enough among petrels of this group. Dr. G. K. Noble has informed me
that the two specimens of the Diablotin preserved in the museum at Guadeloupe
are both light-colored, black-capped birds. Pére Labat’s observations were,
however, made at this island, and Bangs and Penard (1919, 22) have called
attention to the fact that Labat’s plate and text both refer to a bird of uniformly
dark plumage. But only a quarter of a century before Father Labat’s visit to
Guadeloupe, du Tertre (1667, 2, 257), who had visited that island and appar-
ently had witnessed the hunting and tasted the delicate flesh of the petrels,
states with all clearness that the plumage of the birds was ‘‘a mixed black and
white."’ A still further taxonomic complication is introduced by information
advanced by Lafresnaye (1844, 167) and Noble (1916, 372), namely, that two
different sorts of closely related white-breasted petrels formerly bred at Guade-
loupe, the respective birds coming to nest at different seasons, and choosing
quite different altitudes on the island for the sites of their colonies. Lafresnaye
states that the inhabitants distinguished one as the “high petrel,’’ the other as
the “‘low petrel,’’ and that the two kinds were of different sizes. Although
such a distinction is not currently recognized, there seems to be a wide range in
the dimensions of existing specimens of the Black-capped Petrel, and it is un-
likely that the last word upon the subject has been said.
To return to the question of identity of the dark, Jamaican Petrel, I consider
it highly probable that this bird and the Black-capped were color phases of the
same species. Complete or prevailing segregation of two phases in distinct
BLACK-CAPPED PETREL 697
though adjacent breeding grounds is a phenomenon known among other Pro-
cellariiformes, such as Pterodroma neglecta and Puffinus pacificus. It is likely that
even in a single locality there is also a secular succession or alternation of
prevailing plumage-types, as one genetic factor or another gains ascendancy in
a breeding population. This might explain why du Tertre found white-breasted
Diablotins at Guadeloupe during one generation, and Labat black petrels in a
subsequent period. It is likely, furthermore, that the probably dichromatic
petrel discussed in this biography was abundant and widespread in the West
Indies, becoming exterminated in most places soon after the importation of
large numbers of negro slaves and domestic animals. Our only knowledge of
the dark phase, aside from the figures and text of Labat, is based upon the
Jamaican representative, commonly known as Pterodroma caribbaea.
Scott (1891, 355) reports that in February, 1891, a black man named William
King made a trip into the hills of Jamaica in search of a bird which he knew as
the ‘‘dry land booby"’ or Blue Mountain Duck. This bird dwelt in holes in the
cliffs, and had formerly been extensively hunted by the mountain people. King,
himself, had eaten a pair not long before, and had been impressed by the sounds
made by the birds in their holes at night.
After a six days’ search, on the trip referred to, King reported that he had
found the old breeding places, had dug out not less than 25 of the burrows,
and had found a mongoose in some and nothing in the others. We need
go no further in seeking an explanation of the disappearance of the petrel
from Jamaica.
The American Museum's single specimen was obtained by Governor Newton,
of Jamaica, during either April or November, 1879.
In most recent systematic lists the Black-capped Petrel is, in my opinion,
widely separated from its nearest relatives within the genus Pterodroma. Its
kinship with the species phaeopygia is obvious, and is discussed in the next
biography. Indeed, a natural Formenkreis, the members of which differ chiefly
in plumage characters of a simple and familiar genetic type, is clearly repre-
sented by the following four forms: externa of the southerly Pacific (and South
Atlantic?); phaeopygia of the tropical Pacific; hasitata of the Gulf-Caribbean
region; and the recently rediscovered cahow of Bermuda.
GALAPAGOS PETREL
Pterodroma phaeopygia phaeopygia
Cstrelata phaeopygia Salvin, 1876, Trans. Zodl. Soc. London, 9, p. 507, pl. 88, fig. 1 (Chatham Island,
Galapagos Archipelago).
Names: Dark-rumped Petrel. Synonyms of the specific name are alba and sandwichensis, the
latter being applicable to a Hawaiian race.
Adults (sexes alike): Dorsal surface generally brown, darkest on the crown, nape, and quills,
which are fuscous black; feathers of the back, sides of neck, scapulars, and median coverts narrowly
margined with grayish white, which largely disappears with wear; secondaries externally glossed
with gray; primaries white basally and on the inner half of the inner webs; lower back and rump
dusky brown, very slightly tinged with gray on the terminal margins of the feathers; upper tail
coverts distally brown and basally white, the latter area showing as fairly conspicuous patches on
698 OCEANIC BIRDS OF SOUTH AMERICA
either side of the dark rump; feathers around eye like crown, except for a narrow white stripe
adjoining each eyelid; forehead, lores, and cheeks white, slightly mottled at the junction with
the dark plumage and also at the base of the culmen; sides of neck likewise freckled and mottled
along the line between the white and dark plumage; a brownish gray area on the sides of neck and
breast, continuous with the dark dorsal plumage, extending a variable distance toward the mid-
line; throat, breast, belly, and under tail coverts white, with a slight dusky mottling along the
flanks, and a more pronounced grayish patch ovet each thigh; under wing coverts and axillaries
white, with a broad blackish brown border around the forward edge of the wing, some of the
feathers of this band having whitish edges. Iris brown; bill black; feet proximally bluish flesh
color, the distal portion of webs and toes, and the greater part of the outer toe, black.
2 males and 3 females collected off Chatham and Albemarle Islands: wing, 294-304 (299); tail,
Fic. 62. Dorsal and ventral as-
pects of three forms of gadfly
petrels, belonging to distinct oce-
anic regions, which appear to com-
prise a group of closely related,
mutually representative species.
Upper, Prerodroma hasitata (West
Indies, tropical district); middle,
P. phaeopygia (Galapagos, anoma-
lous equatorial district); lower, P.
externa (Mas Afuera, sub-tropical
South Pacific district).
134-137 (135.4); exposed culmen, 33-34.8 (34); tarsus, 37.1-
39.3 (38.2); middle toe and claw, 48.4-50.3 (49) mm.
The length in the flesh of 24 males averaged 412, and of
22 females 407.5 mm.; wing-expanse of 17 males, 102.2, and
of 13 females 102.1 mm. (Loomis, 1918, 102).
Of the two known eggs of this petrel, one was taken
from the oviduct of a dead bird. The two are, respectively,
ovate and elliptical-ovate, with a dull white shell. They
measure 61.4 x 44.1 and 61.5 x 39 mm. (Loomis).
Distribution: Breeding at the Galapagos Islands, and
migrating eastward and southward to the coasts of Peru and
Ecuador and northward in the Pacific at least to latitude 10° N.
The Galapagos Petrel is one of a group of
closely related species which have a practically
world-wide distribution in pan-tropical seas. Not
only does a race inhabit the Hawaiian Islands, but
the Juan Fernandez Petrel (Prerodroma externa), and
its subspecies in the western South Pacific and the
South Atlantic, are among its near relatives, as is
also Pterodroma hasitata. The last is the famous
Black-capped Petrel of the West Indies and, in
view of the well-known faunal affinities between
the Antilles and the Galapagos, it is of particu-
lar interest to note the relationship between hasi-
tata and phaeopygia, species which differ chiefly in
such slight details of pattern as the color of the
rump and the sides of the neck. The differences
between these two are of the same nature, for ex-
ample, as the differences between Pterodroma externa
externa, of Juan Fernandez, and Pterodroma externa
cervicalis, of the Kermadec group. All of the pet-
rels named breed in the higher and humid zones of
islands which have many geographic similarities.
In the course of American Museum Pacific field
work off the coast of northern South America, the
Galapagos Petrel has been frequently observed by
Mr. Beck, Dr. Chapman, and myself at various
GALAPAGOS PETREL 699
positions between the Bay of Panama and the latitude of Point Parifias in
northern Peru. En route from the Canal to Talara during early December, 1924,
for instance, I sighted examples from the steamer every day and at all hours.
Again, I saw a large number a short distance to northward of La Plata
Island, Ecuador, on September 4, 1919, and the bird has proved common in
waters off the Gulf of Guayaquil during September and January of several
subsequent years. Collections made on the Galapagos Expedition of the Cali-
fornia Academy of Sciences, as reported by Loomis (1918, 97), show that this
is one of a number of equatorial southern-hemisphere petrels which migrate
northward across the equator. During July, August, and September examples
have been taken near Clipperton Island, and at other positions well offshore
from the west coast of Mexico.
About the Galapagos, according to Loomis, these petrels are present through-
out the year. They are inclined to shun the bays and shores and to frequent
rather the open sea where large gatherings are sometimes to be observed. The
breeding grounds are in the foggy, humid zone of forests and undergrowth,
where constant use of the machete is necessary for carrying out explorations.
In this belt of Indefatigable Island, at an altitude of 335 meters, Beck found a
male bird incubating a fresh egg on July 22, 1906, the burrow being more than a
meter in length and driven through a soil thickly filled with the roots of ferns
and vines. The nest-chamber, about 35 centimeters beneath the surface, was
lined with dry leaves. The only other egg thus far obtained had already been
taken from the oviduct of a female shot at sea on June 7. The gonads were
considerably enlarged in specimens collected during April. These, and other
observations of the California Academy party as noted below, indicate that the
breeding period is seasonal, and that the Galapagos Petrels leave the islands
during December or thereabouts, to return to land again in April.
Loomis continues his notes on the life history of this species as follows:
During the breeding season they were active over the land at night. A party from the Academy
in camp near the summit of James Island on August 7 were kept awake by their incessant call-notes,
uttered as the birds flew about just above the tree tops. At Indefatigable Island they congregated
close inshore at dusk and circled over the water in loose flocks, from which individuals were
constantly ascending in great spirals to the height of several hundred feet, when they headed
inland. In the interior of the island they were particularly prominent during two hours after sun-
set and during two hours before sunrise, there being an evening flight to the land and a morning
flight away from it. While members of the Expedition were in the forest belt of Indefatigable
Island in November, these petrels were frequently seen and heard in the nighttime as they flew
overhead, but in January none were met with on the island, the land apparently having been for-
saken for the sea.
Usually their call-notes consist of four parts, ‘‘kee-kee-kee-koo,"’ the first three uttered quickly
and the last drawn out. Sometimes the order is reversed and sometimes the “‘koo’’ is omitted.
Occasionally the call-notes were heard in the daytime. A low guttural note was detected on one
occasion when several hundred of these birds were following the vessel picking up the turtle fat
that had been thrown overboard. These petrels were very fond of this fat and it was used to decoy
them within gunshot. Remains of pteropods and coelenterates were found in their stomachs.
At sea their manner of flying did not differ from that of other representatives of the genus met
with on the Expedition. In dead calms they flew near the surface of the water, and two or three
wing strokes were succeeded by a sailing flight of a hundred feet or more. One September day when
700 OCEANIC BIRDS OF SOUTH AMERICA
a strong wind was blowing several were seen ‘‘sweeping along in great arcs, seldom flapping their
wings."’ In flying over the land to their breeding grounds, they flap their wings continually, but
in returning to the water they change their mode of flight, two or three wing beats being followed
by a long sail (Loomis, 1918, 98).
JUAN FERN ANDEZ PETREL
Pterodroma externa externa
Gstrelata externa Salvin, 1875, Ibis, p. 373 (Mas Afuera, Juan Fernandez).
Names: White-necked Petrel; ‘‘Fardela’’ in Chile.
Characters: The gray back, dark crown, and suggestion of a whitish collar distinguish this
petrel from Prerodroma phaeopygia and other relatives in the Pacific.
Adults (sexes alike): Dorsal coloration generally grayish, the feathers being blackish with
broad ashy gray margins, all having white bases, which are more or less exposed on the hind neck
and upper mantle; wing coverts black, the greater series externally gray, except at the base, which
is white; primaries black, the inner ones dark slaty gray, with black shafts and tips; all the quills
white for the greater part of the inner web; secondaries slaty gray, white for the greater part of
the inner web, and narrowly fringed with hoary white like the greater coverts; innermost secon-
daries dark brown, like the scapulars; rump and central upper tail coverts black, the lateral ones
white with broad tips of brown or ashy brown, the longer upper tail coverts slaty gray with con-
cealed white bases; tail feathers slaty gray, the inner webs browner, and also the tips, the outer
feathers white at the base of the inner web, more extended on the outermost feathers, which are
also slightly freckled with gray; crown of head blackish, tinged with gray; forehead and lores
white, with a few blackish spots adjoining the crown; sides of face white, with a few black spots
and streaks; upper and lower eyelid white; feathers in front of and below the eye black, extending
over the ear coverts, which have a few white streaks; cheeks and entire under surface white,
including the under wing coverts and axillaries; edge of the wing slightly mottled with black
spots; on the lower flanks above the thighs, a patch of feathers with broad black tips; quills
blackish below, white for the greater part of the inner webs, which are more or less shaded with
gray. Iris brown; bill black; tarsi and base of toes flesh color, the terminal part black.
60 males from waters about the Juan Fernandez Islands: wing, 302-333 (314); tail, 127.8-
143.1 (137); exposed culmen, 34.4-39 (37.1); tarsus, 36.8-39.9 (38.9); middle toe and claw, 47.2-
53.2 (50.1) mm.
34 females: wing, 311-320 (315); tail, 124.6-138.4 (133.1); exposed culmen, 34.5-38 (36.2);
tarsus, 37.2-40.2 (38.6); middle toe and claw, 46.6-52.8 (50) mm.
Godman (1908, pl. 62) figures a chick covered with gray or brownish gray down. The egg
seems to be still unknown, Mathews's (1932, 33) alleged description not pertaining to the sub-
species of Juan Fernandez.
Distribution: As a breeding bird, the race is confined, so far as known, to Mas Afuera Island,
Juan Fernandez group, from where it migrates northward in the Pacific at least to the latitude of
Costa Rica. The species is characteristic of waters close to the Sub-Antarctic Convergence, with a
well-marked subspecies (cervicalis) inhabiting the Kermadec Islands. In addition, a form has
recently been described from Tristan da Cunha.
This petrel may prove to be a representative of a circumpolar species inhabit-
ing islands in a temperate belt of the southern oceans. Formerly only the Juan
Fernandez and Kermadec forms were known, but in the Bulletin of the British
Ornithologists’ Club, 52, p. 63, Mathews has recently given the following
thoroughly inadequate description of the first example collected in the South
Atlantic:
Pterodroma externa tristani, subsp. nov.
Differs from P. e. externa, from Masafuera Island, Chili, in being darker on the upper surface
and on the wing-coverts. The bill is longer, 38 mm., as against 35 of externa measured the same way
JUAN FERNANDEZ PETREL 701
(and they are constant). The bill also appears heavier. Wing 322 mm.; tarsus 40; middle toe with
claw 51; tail 141. All these measurements exceed those of the same parts in the species.
From P. e. cervicalis it differs in not having the whitish collar on the back of the neck, and in
having the under-wing lining all white.
Type.—Tristan da Cunha, ex the Jack G. Gordon Collection in 1919, now in the Royal Scottish
Museum, Edinburgh, Scotland.
The describer certainly had insufficient evidence for his assertion that the
differences in the length of the bill are constant, for I have shown above that the
length of the culmen among 60 male birds from Juan Fernandez ranges between
34.4 and 39 millimeters. The other dimensions of the Atlantic specimen like-
wise fit well into those of our Pacific series.
During the Brewster-Sanford Expedition, Beck was unable to land at Mas
Afuera Island, but he found this petrel abundant ir the surrounding waters—no
less near Mas Atierra than around the island at which it nests. In December,
1913, and January, 1914, he collected many specimens in the neighborhood of
Juan Fernandez and at points between the islands and the continental coast.
Most of the birds were breeding, as evidenced by the state of their gonads; some
also showed traces of the mud of the burrows on their bills.
According to the investigations of Backstrém, this handsome petrel is the
commonest bird of Mas Afuera, nests being abundant everywhere above an
altitude of 500 meters. It burrows chiefly in the fern belt of the island, making
tunnels in the soil that may attain a length of 3 meters. The nest is unlined, but
fragments of ferns are often scattered in either chamber or passage. During the
day no Fardelas are to be seen at the island, although great numbers may be in
sight over the neighboring ocean. At dusk the incubating birds come forth
from their underground homes, making a terrific noise.
Lonnberg (1921, 13), who records Backstrém’s observations, lists one speci-
men from Mas Atierra, but I judge from the context that this means merely the
shore waters of that island. Certainly this petrel has never been found breeding
at more than one island of Juan Fernandez. Backstrém collected downy chicks
at Mas Afuera during February and March, 1917, and apparently observed the
variable white eggs of the species at a somewhat earlier period, though neither
dates nor measurements are recorded.
That certain examples of this species make a migration into the northern
hemisphere is indicated by Mr. Beck's field work during the expedition of the
California Academy of Sciences, when he shot 15 Juan Fernandez Petrels a short
distance northwest of Clipperton Island, on pee 8, 1905, and 9 additional
examples near latitude 14° 30’ N., longitude 107° W., in October, 1906. These
specimens, reported upon by Loomis (1918, 95), show that a complete moult is
undergone at sea during the summer and autumn season of the northern hemi-
sphere.
Loomis gives in tabular form an excellent list of the characters differentiating
the Juan Fernandez and Kermadec subspecies. The two groups of islands have a
practically identical zonal position, and the life processes of their respective sub-
species apparently synchronize. According to Oliver (1930, 137), the population
702 OCEANIC BIRDS OF SOUTH AMERICA
of Prerodroma externa cervicalis breeds in small communities on the upper slopes
of Sunday Island. During the day the birds are nowhere in evidence, but toward
the end of October they begin to be noisy at evening. Permanent occupation of
the burrows by pairs begins about the middle of November, and eggs are laid in
late December and early January. The young leave the island in June.
I have referred elsewhere to the apparently close relationship of the species
externa to phaeopygia of the Galapagos and Aasitata of the West Indies.
ATLANTIC PETREL
Pterodroma incerta
Procellaria incerta Schlegel, 1863, Mus. Pays-Bas, 6, Procell., p. 9 (‘'Mers australes’’).
Names: Schlegel's Petrel. The species has also been listed under the specific names inexpectata
and haesitata, and it may be the petrel described as sandaliata by Solander from a bird taken off
the mouth of the Rio de la Plata.
Characters: The rich brown coloration of the dorsal surface and lighter brown of the throat,
in conjunction with the white breast and dark under-wing, distinguish this petrel from its con-
geners in the South Atlantic.
Adults (sexes alike): General color of dorsal surface brown (close to olive-brown from forehead
to mantle, and to mummy brown on wings, rump, and tail) many of the feathers with slightly
lighter margins, which become enhanced through wear; greater coverts with narrow but distinct
pale external edges, which are gray only in fresh plumage; primaries fuscous black, paler on the
inner webs and with black shafts; pileum, sides of face, and cheeks brown like the mantle, with a
broad, somewhat ill-defined blackish stripe extending through and beneath the eye and continuing
caudad across the ear coverts; throat and neck brown, the former, however, becoming rapidly
mottled or whitish as a result of wear, leaving a pale brownish collar across the neck; remainder
of ventral surface white, the sides and flanks very slightly washed with ashy brown, which con-
centrates to a definite patch over the thighs; under tail coverts brown, with whitish bases; under
wing coverts and axillaries dark grayish brown. Iris brown; feet flesh color, with the outer toe
largely brown and the other two toes brown at the joints.
6 males, South Atlantic: wing, 317-331 (323); tail, 121.5-138 (130); exposed culmen, 36-39
(37.3); tarsus, 44-46.5 (45.2); middle toe and claw, 59.5-63.9 (62.4) mm.
6 females: wing, 313-335 (322); tail, 127.3-135 (131.8); exposed culmen, 35-38.5 (36.6);
tarsus, 43.5-45.5 (44.5); middle toe and claw, 58.8-64 (61.6) mm.
The young stages have never been described, and the only recorded egg, referred to in the text
below, is not certainly to be associated with this species.
Distribution: Breeds at Tristan da Cunha and ranges throughout sub-tropical and sub-antarctic
latitudes of the South Atlantic and western Indian Oceans.
That this handsome and extraordinarily abundant petrel should still be so
little known is somewhat astonishing. Between the Cape of Good Hope and
the neighborhood of the Brazilian coast close to the tropic of Capricorn, and
from these latitudes southward to the northern boundary of the Antarctic Zone
of surface water, it has been noted by many observers, though collected by few.
During my own work in the South Atlantic I logged the species every day, and
often in vast numbers, between latitude 33° 28’ S., longitude 45° 42’ W. on
November 4, 1912, and latitude 49° 40’ S., longitude 35° 51’ W. on November 19.
This was during the voyage toward South Georgia in the brig ‘Daisy.’ On our
return we encountered the species in almost equal numbers in a more westerly
portion of the South Atlantic, between latitude 49° S. and latitude 31° 24’ S.,
ATLANTIC PETREL 703
during the last ten days of March, 1913. I collected 11 examples on November
9, in latitude 37° S., longitude 46° 30’ W., and one on March 9, in latitude 39°
S., longitude 31° 30’ W. During the course of the Brewster-Sanford Expedition
Mr. Beck saw many examples of the Atlantic Petrel from a steamer about 400
kilometers to northward of the Falkland Islands, on February 3, 1916.
The first direct clue to the breeding ground of the Atlantic Petrel was that
of Nicoll (1908, 64), who found it abundant about Tristan da Cunha during
January, 1905, and subsequently between that island and the Cape of Good
Hope. Mathews (1932, 33) records a skin taken by the Tristan people, together
with an egg supposed to be properly associated with it. The latter is said to
have come from a burrow on a hillside at the “‘Bluff’’ in June, 1918. It is dull
white, bluntly oval, and measures 61.5 x 48 millimeters.
Our sailors on the brig ‘Daisy’ knew the Atlantic Petrel as one of several ‘‘mut-
ton birds,’’ and we found the skinned bodies of this species to be excellent eating.
Godman (1908, 196) considers this petrel to be merely a brown phase of
Pterodroma lessoni. He calls attention to the similarity in dimensions and in the
blackish mark through the eye. To this should be added the significant fact
that /essoni, although an extraordinarily whitish petrel, has a dark under-wing
and that the pattern of coloration on the legs and feet is exactly like that of
incerta. All in all, the two forms look like genetic variants of a common stock.
Since no examples of the gray-and-white or “‘/essoni’’ type are known to nest in
the South Atlantic area, and since the zonal associations of this form appear
to be with colder ocean waters, it may be that the two petrels should be regarded
as representative subspecies. The matter had best be left, however, for further
research into the differences of pigmentation or feather structure, or both, and
until something more has been learned with reference to the possible place of
““Jessoni’’ in the Falkland avifauna. The type is said to have been taken at
those islands, or in adjacent waters. So far as I can learn, there are no other
alleged records for the South American region.
The practical identity in dimensions between the brown and the gray forms
is illustrated by the following figures:
; 4 Exposed Middle toe
Wing Tail adie Tarsus wrid-claw
P. incerta, 6 males, South Atlantic . . 323 130 37.3 45.2 62.4 mm.
P. lessoni, 5 males, on or near Antipodes
Relea test al ee cil a's tease cu azend Geeks 307 128 37 45.1 62.2
KERGUELEN PETREL
Pterodroma brevirostris
Procellaria brevirostris Lesson, 1831, Traité d'Orn., livr. 8, p. 611 (no type locality = Kerguelen Island).
Names: Synonyms of the specific name include Jugens, grisea, unicolor and kidderi.
Characters: A wholly dark gray petrel.
Adults (sexes alike): General color gray (close to the Quaker drab and purplish gray series of
Ridgway’s ‘Color Standards’); most of the feathers with hoary gray bases, which fact produces
704 OCEANIC BIRDS OF SOUTH AMERICA
through exposure of these a certain amount of mottling; wing coverts brownish slate, with gray
margins, particularly on the median and greater series; quills blackish brown, the inner webs
paler; crown like the back but very slightly darker, the forehead and sides of head grayer, and
with an indistinct blackish spot at the inner canthus of the eye; ventral surface slate-gray, palest
on the throat; under wing coverts and axillaries gray, with faintly lighter margins and dark hair-
like shaft-streaks. Iris brown; bill black; feet purplish gray.
One specimen, sex unknown, from Kerguelen Island: wing, 261; tail, 96.2; culmen, 26.4;
tarsus, 37.1; middle toe and claw, 47.3 mm.
Nestlings are clad in sooty brown down, from which they moult into a plumage resembling
that of the adult.
Mathews (1932, 34) records an egg from Kerguelen as measuring 50 x 38 mm.
Distribution: A petrel of the Antarctic Zone of surface water in the Atlantic and Indian Ocean
regions, breeding at Kerguelen Island and recorded southward to about latitude 70° S.
The Kerguelen Petrel has been accepted by most recent writers as a resident
species of Tristan da Cunha, but the only information upon which such con-
clusion rests seems to be the existence in the British Museum of a specimen
purchased from Captain Carmichael and said to have come from Tristan (Salvin,
1896, 410). The authority is therefore very dubious, the more so since we now
know that this petrel is a bird of the Antarctic Zone, ranging far to southward
of Heard Island and into the icy waters of Weddell Sea. Since a dead example
has been found on a west Australian beach after a storm (Mathews, 1928, 102),
it is not unlikely that a stray bird might similarly visit Tristan da Cunha, but
this petrel is almost certainly not a resident of any island in such low latitudes.
The ‘Scotia’ expedition took its first specimen of the Kerguelen Petrel in
latitude 69° 33’ S., longitude 15° 19’ W., not far off the Coat’s Land coast, on
March 20, 1904. Thereafter the species was logged frequently, but nowhere to
northward of about latitude 66° S. (Clarke, 1913, 262). Vanhéffen (1905, 506,
508) records it halfway between Heard Island and Kaiser Wilhelm II Land.
At Kerguelen Island various observers have found this petrel breeding
between October and January. Kidder (1875, 29) obtained examples with eggs
on October 11 and 21. The birds were occupying rather deep burrows, each of
which contained a little pool of fresh water, presumably produced by the thaw-
ing of ice in the soil. A young bird in the down was found on December 13.
The American Museum has but a single specimen of this petrel, which was
collected by Lieutenant Alexander Smith at Kerguelen on May 20, 1898. The
effect of wear and bleaching shows in a faint buffy or rusty tinge, which prob-
ably has no place in fresh plumage.
KERMADEC PETREL
Pterodroma neglecta
Procellaria neglecta Schlegel, 1863, Mus. Pays-Bas, 6, Procell., p. 10 (Kermadec Islands).
Names: Neglected Petrel; ‘‘Fardela’’ at Juan Fernandez. Synonyms of the specific name
include raoulensis, phillipit, and leucophrys.
Characters: A dichromatic petrel, with both black and light brown phases, the two being
connected by intermediates exhibiting a wide range of gray and dusky plumages. The lightest
examples are white-bellied, and also have very light throats and heads. The darkest are nearly
KERMADEC PETREL 705
black, though always with white areas on the throat, in the wings, and usually elsewhere. The
concealed basal portions of the entire plumage are white in every phase, producing a certain amount
of mottling even in the darkest examples. A uniform character in birds of every phase is that the
shafts of the primaries, and the greater part of the inner web of each primary, is largely and con-
spicuously white. This serves to distinguish the species from all of its near relatives, including
Pterodroma arminjoniana of the South Atlantic. The tail is less rounded than in most members of
the genus Pterodroma.
Adults, light phase (sexes alike): Feathers of head, neck, sides, and entire ventral surface,
basally white and terminally drab, producing a variously mottled appearance which may become
almost white on the throat, lower breast, belly, and under tail coverts, and sometimes on the
forehead, lores, and above and below the eye; mantle, back, ramp, wings, and tail darker, between
hair brown and chaetura drab; rectrices basally white and with largely white shafts; primaries
with white shafts and inner webs, as noted above; feathers of crown and back with obsolescent,
gtayish, terminal borders, which are enhanced by wear; an indistinct dark patch beneath and in
front of eye; wing-lining like exterior of wing, but slightly mottled with whitish. Iris brown;
bill black, legs and feet proximally flesh color, distally black except on the outer toe.
Cin an extreme light phase, the entire ventral surface of the body, except the tips of the under
tail coverts, is pure white. We have many such examples from the central South Pacific, but I find
none from the Juan Fernandez group.)
Adults, dark phase (sexes alike): General color throughout varying between grayish brown
and dark brownish black, mottled white areas appearing particularly on the throat, and to a lesser
degree elsewhere; quills of wing and tail, including the white shafts, as above. Legs and feet
black in the most heavily pigmented examples, but parti-colored in some of the less blackish birds.
49 males from Mas Atierra and Santa Clara Islands, Juan Fernandez, and adjacent waters:
wing, 290-307 (297.4); tail, 102-113.3 (105.8); exposed culmen, 29.2-32.5 G1); tarsus, 38.6-41.8
(40.3); middle toe and claw, 51.4-56.1 (53.8) mm.
31 females: wing, 290-309 (300.4); tail, 100.7-112 (106.1); exposed culmen, 29.3-32.8 (30.9);
tarsus, 39.1-43.1 (40.4); middle toe and-claw, 52-56 (53.6) mm.
Among six chicks taken at Mas Atierra, January 14 to February 9, 1914, the younger examples,
not long out of the egg, are clad in a dense down close in color to the dusky drab of Ridgway.
The second down is somewhat lighter; the largest specimen, collected on January 29, has feathers
appearing upon the throat and back.
Eggs are of highly variable shape, though none of our examples are elongate. They are dull
white, and more or’ less stained. The average dimensions of 11 are 65.1 x 46.7, measurements of
the extremes being 67.9 x 45.7, 63 x 43.7, and 66.3 x 50.3 mm.
Distribution: Sub-Tropical Zone of the South Pacific Ocean; breeding at Mas Atierra and Santa
Clara Islands of the Juan Fernandez group, San Ambrosio, numerous islands of southern Polynesia,
and at the Kermadecs and Lord Howe Islands in the western part of the ocean; ranges northward
in the eastern Pacific into the northern hemisphere.
The Kermadec Petrel is a dichromatic, surface-nesting, sub-tropical species,
which breeds from the two landward islands of the Juan Fernandez group
westward along the southern fringe of Polynesia to islands in corresponding
latitudes off the east coast of Australia. Mas Afuera is apparently skipped,
being left to the exclusive occupancy of such related petrels as Pterodroma externa
and Pterodroma leucoptera masafuerae which, in turn, do not nest at Mas Atierra
and Santa Clara. The latter are inhabited, with equal exclusiveness, by Ptero-
droma cookii defilippiana as well as by neglecta. Furthermore, both of the last-
named petrels also breed at one or both islets of the San Felix-San Ambrosio
group, which lies more than seven degrees of latitude north of Juan Fernandez.
In the waters about San Ambrosio, Mr. Templeton Crocker’s party in the
yacht ‘Zaca’ obtained eight adult specimens of this petrel on February 18, 1935.
706 OCEANIC BIRDS OF SOUTH AMERICA
In appearance and measurements these agree entirely with Juan Fernandez
birds. One is wholly dark except for the usual white patch formed by the bases
of the remiges; four are gray, with whitish throats; two have fairly large white
spots on the belly; and one is prevailingly whitish over the entire ventral sur-
face, although most of the feathers are dark-tipped. In the darker birds the
feet are entirely blackish brown. In the lightest example, the metatarsus and
bases of the inner toes and webs are dark brownish, the distal parts and the
outer toe blackish.
Dr. Chapin reports that no examples were observed at sea the day before
making San Felix, and only a very few near that islet, where the species appar-
ently does not nest. Halfway toward the neighboring islet of San Ambrosio,
the petrels became common. About half-past four o'clock in the afternoon,
hundreds of them could be seen circling about over the summit of San Ambrosio,
an aérial performance which continued at least until dusk. No landing was
made by the ‘Zaca’ party, the three female and five male birds being obtained
over the water close to the cliffs of the steep island.
Loomis (1918, 102) has shown that the Kermadec Petrel migrates northward
in the eastern Pacific to about latitude 15° N., where two examples were col-
lected and others observed by Beck during October, 1906.
On the voyage between Valparaiso and Juan Fernandez, Beck began to ob-
serve the Kermadec Petrels when his vessel was about halfway toward the
islands. At Mas Atierra, on December 12, 1913, he saw the birds issuing from
their hiding-places about four o'clock in the afternoon to sail along the cliffs,
the majority of them keeping for a time at an altitude of 300 meters or more
above the sea. He succeeded in shooting two at moments when they had swung
in over the land, but most of them kept well out from the face of precipices
that rose sheer from the ocean toward the peak known as la Centinela. Kaéck-
cow-ow-ow-ow was their call as they flew, quite different, Beck remarks, from the
note of the Pink-footed Shearwaters. From his high vantage point, Beck could
also see Kermadec Petrels scattered over the ocean for a long distance from shore,
mingling with storm petrels, Black-browed Albatrosses, and other sea birds.
On December 15 he found the first of these petrels on their nests, which were
under the shelter and shadow of rocks and on ledges of the cliffs or steep slopes.
Most of them were in sites which the sun could reach only at midday, if at all.
Some of the birds were sleeping, their bills tucked under the wing coverts.
They were thoroughly tame and could be caught on the egg, although they
scolded and struck with their bills when they were disturbed. Iredale (1914,
423) also reports adults at the Kermadec Islands as being gentle and inoffensive
at the nest, but he adds that the young birds are negatively conditioned against
being touched, usually responding with loud outcries.
The first nest Beck found contained two eggs, one of which was ancient and
rotten, suggesting that a last year’s site had been used again, with no effort to
get rid of the old egg. Eggs were common between December 15 and January 17.
The nests, which were lined with more or less fine grass, by no means all con-
tained eggs; in December Beck saw several pairs of the birds building together,
RERMADEG PETREL 707
one of them occasionally standing up on straight legs to walk about restlessly
for a few moments. About four o'clock in the afternoon of each day they began
to take to the air, first sailing back and forth along the cliffs and then flying
off to sea.
The majority of Beck’s Juan Fernandez specimens are relatively dark birds,
though the lightest show a small white area on the belly that is almost or quite
without bars or other markings. Not one has as much white on the ventral
surface as have many adults from more westerly districts in the South Pacific.
Chicks became common at Mas Atierra after early January. A “‘half-grown’’
example has been collected by Backstrém on March 13 of a subsequent year
(Lénnberg, 1921, 12).
Backstrém estimated that the numbers of these petrels had become reduced
to a few hundred at the date of his visit to Mas Atierra. It is not known to what
extent the occupation of the island by sealers, convicts, ranchers, and lobster
fishermen may have affected the population of the birds which, in the western
Pacific, are eagerly sought as human food, but it is quite likely that the breeding
area at Juan Fernandez was once far more extensive than at present, and that
the nests on the ledges of more or less inaccessible cliffs represent merely the
residuum after long persecution by man and his introduced domestic animals.
In the Kermadec Islands there are very large colonies of this petrel which
have been studied by Iredale and others. One inspection of the nesting birds at
Sunday Island showed that, of 264 examples incubating eggs, about 40 per cent
represented the light phase, an equal proportion the dark, while the remaining
20 per cent was made up of intermediates. Furthermore, among 35 mated pairs,
19 were observed to be composed of similar birds, and 16 of odd or dissimilar
birds. In one instance, two black birds were mated, and in another, one black
and one very dark gray bird. Iredale also noted the variable condition in the
legs of this species, some examples of the dark phase having parti-colored or
‘‘sandaled”’ legs and feet, like those of birds in the light plumage, while in other
dark birds the tarsi and feet were entirely black.
The nesting season is evidently somewhat prolonged at the Kermadecs;
during January, when the majority of mated birds had eggs, there were also
some half-grown young, and Cheeseman (1869, 225) refers to the same condition
during the month of August. This, however, was at Meyer Island where, ac-
cording to Oliver (1930, 138), the birds have a different breeding period from
those of Sunday Island, correlated with certain differences in plumage and voice.
At Sunday Island the petrels occupy flat ground, usually in the shelter of a fern-
growth, but sometimes in the open. Iredale saw multitudes of them circling
about trees just after sunset, uttering plaintive cries as if to let their mates know
that they were returning. After dark most of the calls ceased, the period of
mating being already past. The relieved birds would depart for sea just before
sunrise. Territorial competition was observed whenever circumstance caused
two families of petrels to nest inconveniently close to each other. In some such
instances the respective pairs of parents would quarrel to the exclusion of prop-
erly feeding their young, dwarfed starvelings being produced as a result.
708 OCEANIC BIRDS OF SOUTH AMERICA
Oliver (1930, 141) states that the food of the Kermadec Petrel consists mainly
of crustaceans and cephalopods. He adds the following comprehensive notes
covering ten months’ observation at Sunday Island:
The birds are first seen flying out at sea early in August. Each evening they appear to come
nearer the island and by the 22nd a few were found on the ground. They breed on the surface,
scratching a shallow hollow. This operation was actually observed by Bell who states that he
saw a bird go under a log, fluff out its feathers, stand up and then lean forwards on its breast and
scratch the earth backwards with both feet at once. In half an hour’s time a hollow about eight
inches across and two inches deep was made. The birds then collect sticks and leaves and make a
nest. This completed, they leave the island for two or three weeks and then return to lay.
Eggs are plentiful in the beginning of November. Fresh eggs have been noticed as early as
October 20th and as late as December 6th. The period of incubation is 50 to 52 days. The first
young ones are to be seen about the middle of December. They are plentiful after December 20th,
and most will be hatched by the end of January. They remain in the nest where they are fed by
the parents for over three months, during which time they become very fat. Towards the end of
May, the adult birds leave Sunday Island and the young are left to find their own way to sea.
After the parents cease to feed them, the young gradually get thinner, and in ten days or a
fortnight’s time walk away from their nest, climb up on to a stone or tree trunk and take their
first flight. This is rather an unsteady one straight out to sea. Most of the young fly in April and
May but a few late ones may be seen during the first week in June.
The alimentary tracts of all the examples obtained by the ‘Zaca* expedition
at San Ambrosio contained mandibles and pens of squids.
SOUTH TRINIDAD PETREL
Prterodroma arminjoniana
selon Arminjoniana Giglioli and Salvadori, 1868, Atti Soc. Ital. Sci. Nat., 11, p. 452 (South Trinidad
Island).
Names: Synonyms of the specific name of this petrel include sandaliata, wilsontt, trinitatis,
chionophara, and several earlier names of less certain application.
Characcers: A dichromatic species closely related to and generally resembling Pterodroma
neglecta, from which it differs notably in having dark quill shafts in all phases and in lacking the
pronounced white area which, in meglecta, covers practically the entire inner web of the outer
primaries. The dark phases of the two species, and some of the intermediate phases, are otherwise
almost indistinguishable. The light phase of arminjoniana apparently always has a finely barred
dusky collar dividing the white throat from the white breast.
Adults, light phase (sexes alike): Dorsal color ashy black, the feathers of the back, caudad
from the nape, mottled with white bases; scapulars and wing coverts blackish, washed with slaty
gray, the greater coverts for the most part slaty gray, with dusky margins; quills dusky black,
ashy brown for the greater part of the inner web, the secondaries mostly blackish, ashy brown
towards the ends of the inner webs, and mottled with blackish vermiculations toward the end of
the outer web; upper tail coverts and quills blackish, with a slight ashy shade; crown of head and
sides of face like the back, the feathers below the eye and the ear coverts slightly mottled through
exposure of the white bases; throat white, slightly mottled with dull ashy bars, with which most
of the feathers are tipped; remainder of under surface of body white, except for a broad collar of
ashy brown across the fore neck, continued down the sides of the upper breast and sides of the
body; on the latter a few bars of ashy brown, and also a few similar bars below the prepectoral
collar; on the flanks a few blackish shaft-streaks, causing a streaked appearance; under tail coverts
slaty black, with white bases and narrow white fringes at the ends, some of the basal coverts
white, with a double or single bar of ashy gray near the end; under wing coverts dark brown,
shaded with ashy, some of the inner median and greater coverts largely white; primary coverts
white at the base; quills dusky brown below, more ashy on the inner web, which is white towards
SOU GA LRN LDAD PETREL 709
the base and margins of the primaries, and on the secondaries extends along most of the inner web.
Iris brown; bill black; tarsi and base of toes flesh color, remainder of toes, webs, and outer side of
outer toe, black.
Adults, dark phase: Similar to the dark phase of Prerodroma neglecta, except for the wing char-
acters noted above. Legs and feet black.
7 males: wing, 293-309 (301.5); tail, 109-116.5 (113.2); exposed culmen, 28-31.2 (29.6);
tarsus, 35.5-40 (38.7); middle toe and claw, 45.7-50.4 (47.9) mm.
8 females: wing, 275-295 (286.1); tail, 108.2-112 (110.4); exposed culmen, 27.7-30.1 (28.6);
tarsus, 35.1-37.7 (36.1); middle toe and claw, 44.8-50.4 (47.1) mm.
Lengths in the flesh of 9 adults ranged between 374 and 396 mm.; wing-spreads of the same birds
between 949 and 1025 mm.
Young birds are described as clad in dark gray down. In a black fledgling of the American
Museum Collection, the remaining patches of down lack entirely the brownish and sooty tone
characteristic of Pterodroma neglecta.
Distribution: Breeding at South Trinidad Island and the neighboring Martin Vas Rocks.
Normal flight-range apparently confined to contiguous parts of the South Atlantic, though the
species is known casually to have reached the northern hemisphere.
The South Trinidad Petrel is clearly a representative in the Atlantic of
Prerodroma neglecta. Possibly it should be regarded as a subspecies of the latter,
although the differences are strongly marked, the most striking and constant
distinction between these two highly variable birds being the fact that even
the darkest examples of neglecta have white primary shafts and inner webs,
while in all examples of arminjoniana these are relatively dark. Correlated with
such characters of pattern, it appears that the South Trinidad Petrel occupies
a warmer zone of surface water, somewhat nearer the equator than any part of
the breeding range of the Pacific form. Both Atlantic and Pacific species are,
nevertheless, definitely sub-tropical rather than either tropical or sub-antarctic.
The American Museum contains an excellent series of this petrel taken during
my visit to South Trinidad in April, 1913, and others, including a downy chick
and a fledgling as well as adults, captured during the South Atlantic Expedition
of the Cleveland Museum of Natural History, between December 24, 1924, and
January 5, 1925. All phases, from birds with white breasts and throats to those
of entirely black plumage, are represented, besides which at least one specimen
shows a tendency toward albinism on the head and neck. According to Simmons
(1927, 27), the Cleveland Museum party found the species abundant at the
middle island of the Martin Vas group as well as at Trinidad itself.
Lowe and Kinnear (1930, 137) have studied a series of these petrels in the
British Museum, and have correlated their results with the field observations
of Wilson and others. They find that the petrel population of South Trinidad
is broadly made up of birds of three categories, as follows:
(a) A light phase with white and black feet and legs.
(6) A dark phase with all-black feet and legs. «
(c) An intermediate phase with pink and black feet and legs.
They quote, furthermore, certain observations to indicate a segregation of color
pattern in the field. Nicoll (1906, 672) remarks, for example, that the birds of
the dark phase are rarer than the light ones, and that their nests are found only
710 OCEANIC BIRDS OF SOUTH AMERICA
at a higher altitude on the island. That the latter observation was merely a
result of chance, however, is indicated by the testimony of both Dr. Wilson
and the Cleveland Museum naturalists, who found black-breasted and white-
breasted birds intermated and occupying the same niche. The relationship
seems to be exactly as reported for Prerodroma neglecta at the Kermadec Islands.
Furthermore, the data of Lowe and Kinnear as to breeding periods would seem
to be inadequate, for there can be little doubt that at South Trinidad the nesting
of this species continues throughout the year. That there may be certain nodes
in productiveness is quite likely but, on the other hand, the fact that Wilson
found eggs in September, and downy young but no eggs in July, may be nothing
more than accidental. :
Our American Museum specimens exhibit a greater diversity of plumage
than is indicated in the paper by Lowe and Kinnear. I have already listed the
six or seven recognizable phases between the blackest “‘trimitatis’’ stage and
the mainly white “‘chionophara’’ (Murphy, 1915, 343). The two chicks in our
collection represent both typical arminjoniana and ‘‘trinitatis’’ phases; they were
collected, respectively, in the Cascade Valley and the Waterfall Valley, South
Trinidad, on the same date, December 28, 1924. The light-breasted bird is a
female and the black one a male.
During the cruise of the ‘Daisy,’ I first identified the South Trinidad Petrel
on April 4, 1913, in latitude 25° S., longitude 30° 40’ W., nearly four degrees
to southward of the island. The species became increasingly common during
the next three days as we approached its headquarters. Birds of the black phase
were noted chiefly in the immediate vicinity of the island, and none of any kind
was seen after we had passed out of sight to northward.
Throughout my one day in the waters beneath the beetling cliffs of South
Trinidad, April 8, 1913, these petrels, together with noddy terns, were the
most numerous birds at and about the island. The petrels were incubating, or
perhaps only resting, in water-worn cells of the inaccessible rocks. They fre-
quently bickered with one another in the air, chattering with voices not unlike
those of terns. They were perfectly fearless of men, but not in the least inter-
ested, so that their behavior was quite unlike that of the inquisitive noddies.
Birds in the black or “‘trinitatis’’ phase seemed definitely less abundant than
those of the white-breasted or arminjoniana type. The specimens I shot had
evidently not long since bred, and there were large bare patches on their abdo-
mens. When a remarkably white petrel flew over our boat, in passing from the
sea toward the great basaltic column called the Ninepin, I recognized it as a
bird of unfamiliar type. A fortunate long shot brought it hurtling to the water,
and we reached it sooner than the sharks which had already succeeded in pulling
under one or two of our prizes. The specimen proved to be a new and previously
unknown plumage phase, characterized by a black-flecked, ermine-like cloak.
It is doubtless a partial albino, though the symmetry of the pattern is unusual.
The example is the type of **Pterodroma chionophara.”’
The South Trinidad Petrel has been reported at least twice from the northern
hemisphere. One recorded by Lowe (1911, 223) struck the rigging of the yacht
FOUL DRINIDAD PET REL 711
‘Zenaida’ on December 31, 1905, in latitude 21° 51’ N., longitude 43° 35’ W.,
a point in mid-Atlantic almost equidistant from the Lesser Antilles and the
Cape Verde Islands but to northward of either. As already noted in my section
on birds and hurricanes, an example constituting the first record for North
America was taken near Ithaca, New York, on August 24, 1933. After being
forcibly fed with pieces of fish, this petrel learned to pick dead minnows from
a pan of water, but made no effort to catch live ones. It lived a little over a
week (Allen, 1934, 134). The specimen is preserved in the Cornell University
collection and has been sent to me for examination. It is a typical example of
the dark phase of the South Trinidad Petrel. The capture followed close upon
the heels of a tropical cyclone, the course and duration of which I have already
indicated. The storm struck the north Atlantic coast near Cape Hatteras on
August 23 and continued due northward toward the Finger Lakes region of
central New York and then on to the St. Lawrence valley. Smaller petrels of
at least three species were found stranded in various parts of the Middle Atlantic
States and Canada after the same disturbance.
SOFT-PLUMAGED PETREL
Prerodroma mollis mollis
Procellaria mollis Gould, 1841, Ann. Mag. Nat. Hist., 13, p. 363 (South Atlantic Ocean).
Names: Mutton Bird; this is one of the species called Night-bird or White-breasted Eaglet at
Tristan da Cunha. According to Verrill (1895, 449), it is the Pediunker or ‘‘Paddy Unker”’ of
that group, but Mathews (1932, 29) states that this name is restricted by the inhabitants to
Adamastor cinereus. A synonym of the specific name of this petrel is dubius, besides which it has
appeared in the literature under several names properly applicable to other species.
Characters: Distinguishable from most or all other small petrels of the South Atlantic by its
gray dorsal color in combination with a white breast and gray under-wing.
Adults (sexes alike): General color of the dorsal surface slaty gray, with lighter indistinct
margins on the feathers of the mantle; wing coverts and longer scapulars blackish brown, the
greater coverts shaded with ashy gray and having more or less obsolete fringes of hoary white;
primaries blackish brown, paler on the inner web and internally edged with whitish; secondaries
of the same color externally, margined with ashy gray like the greater coverts; lower back and
rump slightly more dusky than the mantle; upper tail coverts and central rectrices ashy gray,
the three outer quills mostly white on their inner webs, and finely vermiculated with ashy gray;
crown of head browner and slightly darker than the back; forehead with a mottled or scaled
appearance, owing to the covering of feathers with dark centers and whitish margins; lores, sides
of face, and lower cheeks white, sparsely speckled with dusky gray feather-tips; feathers in front
of and below eye black, forming a broad stripe which extends caudad over the ear coverts; chin
or interramal space mottled gray; remainder of ventral surface white, except for a partial or com-
plete collar of gray bars or frecklings which extends ventrad from the sides of neck; a few variable
ashy gray markings along the sides and flanks, sometimes taking the form of sagittate spots; under
tail coverts white; under wing coverts dark slaty brown, with paler or whitish borders, the mar-
ginal coverts blackish brown; axillaries dark slate, with white bases, and sometimes freckled with
white. Iris brown; bill black; tarsus and proximal third of foot flesh color or pinkish, the remainder
and the whole outer toe deep brown.
7 males: wing, 247-268 (256); tail, 106.5-117 (110.5); exposed culmen, 26.8-29.2 (28.5);
tarsus, 34-36 (35); middle toe and claw, 42.5-46.8 (45.2) mm.
2 females: wing, 250-262; tail, 108-112; exposed culmen, 26.9-28.3; tarsus, 35; middle toe
and claw, 44.5-44.8 mm.
712 OCEANIC BIRDS OF SOUTH AMERICA
The length in the flesh of one specimen was 37 cm.; the wing-spread of 7 males ranged between
86 and 91 cm.
Downy young apparently remain undescribed. The egg is white and dull-surfaced, two ex-
amples measuring 63.5 x 49.8, 64 x 49.6 mm. (Mathews, 1932, 33).
Distribution: Breeds at the islands of the Tristan da Cunha group and at Gough, in the South
Atlantic; at St. Paul Island in the Indian Ocean. It is also said to be a resident of Kerguelen, which
needs verification. Its flight-range apparently covers the entire South Atlantic between latitudes
25° and 50° S. One or more very distinct races breed in the eastern part of the sub-tropical North
Atlantic.
This abundant and familiar petrel of the South Atlantic and Indian Oceans
has representative, or at least closely related, forms or species in several other
oceanic areas. The typical race seems, however, to exhibit well-marked dis-
tinctions, and to be especially characteristic of sub-tropical and low sub-
antarctic waters, Close to the convergence of the two zones. For such reasons
I doubt the presence of the same race at Kerguelen Island, which belongs to a
totally different zone of surface water. That the species breaks down into local
geographic races is indicated not only by the presence of a markedly distinct
subspecies at the Cape Verde Islands in the tropical North Atlantic, but perhaps
also by the fact that Mathews (1934, 178) has recently described a number of
other races from various cooler parts of the same ocean.
During my South Atlantic cruise in the brig ‘Daisy,’ I saw the Soft-plumaged
Petrel in large force during the months of November and March. When south-
ward bound, we picked up the species in latitude 35° S., on November 5, 1912,
after which examples were seen about the brig almost daily down to latitude
47° S., and eastward of the longitude of South Georgia. On the return voyage,
in March, they were observed for 13 consecutive days, nearer the South American
continent and in the Jatitudes of northern Argentina and southern Uruguay.
The chart of Dabbene (1923, 30) demonstrates not only the extensive flight-
range of this bird, but also that it is confined to a zone well to northward of
antarctic surface water.
Contrary to Alexander’s (1928, 54) statement that this petrel pays no atten-
tion to ships, I found it to be one of the species readily caught on a line baited
with loggerhead turtle meat or other attractive lure. After taking the hook
the birds would fly high, so that the process of capturing them was like hauling
ina kite. Others have preceded me at this sport. Gould (1865, 454), for instance,
was attempting to capture a petrel of this species with hook and line in the
South Atlantic when a gust of wind blew overboard a piece of parchment, in
a fold of which he kept his salmon flies. Next day, he tells us, ‘I succeeded in
capturing the bird with a hook I had still left, and the reader may judge of my
surprise when on opening the stomach I there found the piece of parchment.
Here is one of many bits of testimony which should answer those who doubt
that the same individual petrels sometimes follow ships day after day.
The largest flocks of this species were observed by me in latitude 37° S.,
longitude 46° 30’ W., on November 9, 1912. On March 22, 1913, in latitude
43° S., longitude 33° W., numbers of the birds followed us all day and continued
after nightfall, when they could still be seen swooping about in the moonlight.
SOFT-PLUMAGED PETREL 713
American Museum specimens include not only the series collected during
my cruise, but also others obtained by the Cleveland Museum Expedition in
waters more or less midway between Tristan da Cunha and St. Helena, during
August, 1925.
The ‘Challenger’ expedition first reported the Soft-plumaged Petrel as a
breeding bird of Nightingale Island in the Tristan group, where specimens were
taken on October 17, 1875 (Sclater, 1878, 571). It appears also to be the ‘‘gray
petrel about the size of a pigeon’ referred to by Thomson (1878, 156) as nesting
in patches of woodland below the cliffs of Inaccessible Island, the trees overhead
being the sites of noddies’ nests. The petrel burrows made the floor of the grove
resemble a rabbit warren. Their entrances were more or less concealed among
rocks and moss and the fallen limbs and boles of buckthorn trees.. In this damp
and tangled environment the muffled voices of the birds could be heard under-
ground. According to information which Thomson doubtless obtained from
the marooned Stoltenhoff brothers, these petrels first come to land in early
September, begin their active courtship about the first of October, and lay their
elongate white eggs early in November. Mathews (1932, 33.) writes that the
Soft-plumaged Petrel was found breeding at Tristan da Cunha during November,
1917, and all the known eggs, found in burrows on a slope, have been taken
during the same month.
Wilkins (1923, 508) found three of the birds in hillside burrows near the
beach at Gough Island, between May 28 and June 1, 1922. At evening during
these days many others were observed coming in from sea. Since none of the
captured examples were in breeding condition, we have here evidence of the
interesting and only recently appreciated fact that certain sub-antarctic petrels
are largely given to making use of their nesting sites as places of rest. In this
connection, it is noteworthy that the staff of the Scottish National Antarctic
Expedition observed great numbers of this species off Gough Island during the
month of April, and secured three specimens (Clarke, 1913, 285).
Tue SMALL Petrets oF THE GENUS PTERODROMA
The smallest of the typical ‘‘gadfly petrels’’ comprise two species with wings
not more than about 25 centimeters in length, which break up into numerous
geographic races, some of which are very strongly marked. The group is some-
times segregated under the generic name Cookilaria. The two species are dis-
tinguishable as follows:
1,—Crown, nape, sides of neck and breast, concolor with back, and close to the neutral gray
Beries OU Ridge wayis,Golor Standards.) tn. elie deter oe aie eu oy ounh eee ne Pterodroma cookit.
~ 2.—Crown, nape, sides of neck and breast, much darker than back, forming a sharp contrast,
ud nat ys SOOky. blacksgai. tiated. tanta, cela aes ee ote w ea tat oe mn She Pterodroma leucoptera.
Examples of P. cookit always have more or less white on the inner vanes of
the primaries; in Jewcoptera the condition is more variable. Moreover, the races
of the latter species are mostly smaller, with relatively longer tails. A careful
714 OCEANIC BIRDS OF SOUTH AMERICA
study of coloration and proportions, however, shows that the simplest and
most certain way to distinguish the two species is by means of the invariable
characteristics noted in the above key. In other respects, the races of both
exhibit a certain parallelism in the nature of their variations.
The distribution of both species is confined, so far as known, to the Pacific
Ocean. Pterodroma cookii is in the main to be associated with the Sub-Antarctic
Zone of surface water, although representatives of the species migrate across
the equator into the northern hemisphere. Pterodroma leucoptera, on the other
hand, is a bird of pan-tropical affinities. Both species come into close juxta-
position at the Juan Fernandez Islands, Chile, where P. cookiz occupies Mas
Atierra, and P. leucoptera, Mas Afuera. It is very interesting that the nesting
localities of the two petrels are thus mutually exclusive, and still more so that
the sub-antarctic species inhabits the island closer to the cool littoral waters of
western South America, while the pan-tropical species is confined to an island
lying two degrees of longitude farther westward, and consequently in warmer
seas.
The breeding grounds of certain subspecies of each of these petrels are still
unknown. Four forms, apparently, have occurred within our region.
COOK’S PETREL
Pterodroma cookii orientalis
Pterodroma cookii orientalis Murphy, 1929, Amer. Mus. Novit., No. 370, p. 5 (200 miles west of Callao, Peru)
Since the typical form was described from the opposite or western side of the South Pacific,
I give below the reference and description.
Procellaria Cookii Gray, 1843, in Dieffenbach’s ‘Travels in New Zealand,’ 2, p. 199 (New Zealand).
Names: This species has been named in books Cook's or Blue-footed Petrel; sometimes, when
combined or confused with P. Jeucoptera, it has been called White-winged Petrel. A synonym of
the specific name is velox, besides which the bird has been listed under several subspecific names
applicable to its races or to those of /eucoptera.
Characters (of the species cookiz): Defined on the preceding page, in comparison with those of
P. leucoptera.
Adults, of the typical race, P. cookit cookii (sexes alike): Forehead, mainly white, but with a
freckling of gray-centered feathers from the median base of the culmen, the gradual transition
from white to gray plumage taking place on the anterior part of the crown, in the lores, and along
the cheeks and sides of neck, which have a somewhat scalloped effect; crown, nape, interscapulars,
lower back, upper tail coverts, sides of neck, and sides of breast, gray (slightly lighter and more
slaty than the neutral gray of Ridgway), the feathers of all these parts more or less margined with
white in fresh plumage, most persistently so on the anterior part of the crown and the sides of
neck and breast; (prolonged wear exposes the darker subterminal parts of the feathers, causing the
crown and back to appear somewhat spotted with dark neutral gray and to show the blackish
streaks of the feather shafts); a large, roughly triangular, blackish brown patch on the rump; a
narrow white infraorbital line, not easily discernible in all specimens, and beneath this a conspicu-
ous broader stripe of dark neutral gray or blackish, which loops around the anterior canthus of
the eye and extends caudad over the ear coverts, widening as it blends with the gray feathers along
the side of the neck; the boundary between gray dorsal, and white ventral, plumage more or less
mottled through the intermingling of the colors along the cheeks and sides of neck and breast,
some specimens showing also a faint dusting of gray along the white flanks; wings, blackish
brown (3), with horny brown quill shafts, becoming lighter basally; the greater coverts and sec-
COOK'S PETREL 715
ondary quills contrast with the remainder of the wing in that they have a distinct neutral gray
bloom and are externally and narrowly margined with white; inner vanes of remiges largely white,
the sharply marked white areas on the primaries extending as a pointed wedge from the base
throughout about three-quarters of the length of each quill; central rectrices, largely neutral gray,
terminally tinged with blackish brown; lateral rectrices, generally comprising the four outer
pairs, somewhat variable, but as a rule white, heavily speckled with light neutral gray; inner
webs of these quills sometimes pure white, sometimes pale gray, and sometimes showing an inter-
mediate speckling; outer webs, usually either solidly gray or heavily speckled; entire ventral
surface of body, from chin to under tail coverts, white; lining of wing, white, except along its
anterior edge, where a mixture of blackish brown, white, and neutral gray feathers with white
emarginations, produces a narrow, irregularly mottled border.
Considerable variability is noteworthy in the amount of white emargination on the dorsal
plumage, the conspicuousness and extent of the blackish infraorbital patch, the extent of white
feathering above the eye, which sometimes gives the appearance of a supra-orbital stripe, the
general hue of the gray parts of the plumage (due mainly to wear), the conspicuousness of the
rump-patch, which is in some cases only slightly evident, and the wide range in markings on the
outer quills of the tail.
All forms of both P. cookii and P. leucoptera seem to have black bills and, of course, brown irides.
The only differences in flesh colors are those of the tarsi and feet. In American Museum specimens
of P. c. cookii, these are noted as ‘‘tarsus, upper third of foot, and inner toes, blue; remainder black.”’
Subspecific characters of P. cookii orientalis: Very similar to the typical form, but averaging
larger, and with a more pronounced appearance of scalation on the dorsal surface, due to a broader
and more general white emargination of the feathers.
19 specimens of both sexes: wing, 234-250 (239); tail, 85-97 (91); exposed culmen, 27.6-30 (29);
tarsus, 30-32 (31); middle toe and claw, 38-41 (40) mm.
Distribution: Breeding ground unknown. Common off the west coast of South America, in
the milder ocean waters to westward of the upwelling zone of the Humboldt Current. Examples
have been collected from 80 to 700 kilometers off the coasts of Peru and Chile, between latitudes
5° and 34° S., and also in the eastern North Pacific.
This eastern Pacific representative of the petrel known in New Zealand as
the ‘'Titi’’ is a ‘‘weak’’ subspecies. Its distinguishing characters seem, how-
ever, to be constant, judging from the good series of specimens compared. If
the breeding ground should subsequently be discovered at a New-World island,
the puzzle regarding its status and distribution would be solved.
During the Brewster-Sanford Expedition, Mr. Beck saw the first examples
of this petrel near Hormigas de Afuera Islet, west of Callao, Peru, on June 4,
1913. Subsequently he collected many far off the central part of the Peruvian
coast, and in December took others within sight-of Mas Atierra Island, Juan
Fernandez. It is certain that this subspecies does not nest at Juan Fernandez,
which is occupied by another subspecies of Prerodroma cookii. Hormigas de
Afuera, about which the petrels were seen during southern-hemisphere mid-
winter, is an even more unlikely breeding ground, for the island is tiny, low,
plantless, and more or less overswept by spray.
Furthermore, the nesting petrel of the islands of San Felix and San Ambrosio,
north of Juan Fernandez and close to latitude 26° S., is now known to be Prero-
droma cookii defilippiana, the same form which inhabits Mas Atierra. Through
the courtesy of Dr. Percy R. Lowe, I have been enabled to examine a British
Museum specimen collected at San Ambrosio by Coppinger on July 21, 1879.
Possibly P. c. orientalis nests in the higher parts of certain little-known islands
716 OCEANIC BIRDS OF SOUTH AMERICA
along the coast of south-central Chile. The environment here would be most
like that in which the typical subspecies breeds in New Zealand.
P. c. orientalis is the closest to the typical form of any of the races of cooki#.
Beyond a doubt, the bird has more than once been confused with defilippiana.
To an ornithologist with only one or two examples of each at his disposal,
such confusion might be almost unavoidable. When, however, the two are
represented by good series of specimens collected throughout the same oceanic
region, and reinforced by breeding examples of defilippiana taken from their
nests, such doubts are immediately resolved. P. c. orientalis has a slender and
smooth black bill of exactly the same type as that of cookiz from New Zealand.
P. c. defilippiana, on the other hand, has a remarkably deep, heavy bill, in which
the plates of the latericorn, unguis, etc., have a strong tendency to be rugose,
and even to develop a laminated aspect, so that they are more or less marked
with fine horny lines. The bills of fledgling young, as well as adults, of defilép-
piana, have, as a matter of fact, this characteristic appearance, and even in such
early stages they are pronouncedly deeper and heavier than the bills of adult
specimens of P. c. cookiz and P. c. orientalis.
Under the subspecific name defilippiana, Wetmore (1923, 171) has recorded
two petrels from the northern Peruvian coast, which prove, upon reéxamination,
to be of the present race, oréentalis. Both flew aboard the steamship ‘Santa Elisa,’
and were preserved by the ornithological wireless operator, Mr. C. L. Fagan,
who is responsible for many interesting sea-bird records. The northernmost of
the two specimens was taken north of Lobos de Tierra Island on July 31, 1922.
Bishop (1934, 77) has recorded an example of this petrel which was one of
two to come aboard a ship during a storm in August, 1933, near Adak Island,
of the Aleutian Chain, Alaska. I have examined this bird and find that it com-
pletely agrees with those from the eastern South Pacific. Furthermore, Loomis
(1918, 94) has reported upon nineteen specimens, presumably of this form,
which were collected by Beck on July 22, 1905, in latitude 22° 25’ N., longitude
112° 40’ W., during the Galapagos Expedition of the California Academy of
Sciences. The locality is between the Revilla Gigedo Islands and Cape San Lucas,
Lower California. These specimens were at this date passing through a com-
plete moult of the plumage. I have not seen them, but the dimensions of thir-
teen, as tabulated by Loomis, substantially agree with my measurements of
Pterodroma cookii orientalis from the type locality.
Since nothing whatsoever is known about the breeding habits of this petrel,
I append a brief summary relating to the life history of its conspecific New
Zealand race, Pterodroma cookii cookit.
Buller (1888, 217) states that the Cook's Petrels fly low over the ocean and
often look like huge moths. Their dark wings contrast with the gray and white
body plumage and make it easy to distinguish them from other small petrels.
Cit should be remembered, however, that this author:and other observers of his
day were wont to confuse a number of races of small gadfly petrels representing
both this species and P. leucoptera.)
A well-known breeding ground is on Little Barrier Island, off northern New
COOK'S. PETREL TAG
Zealand. Here the burrows of the Cook’s Petrels are mainly on sloping ground
of the higher ridges, above an altitude of 400 meters which is about halfway
between sea level and summit. The holes wind down deeply beneath the roots
of trees, beyond the reach of foraging hogs, penetrating a rich, black forest
humus, which is usually sodden with moisture. At their entrances they are
from 10 to 15 centimeters in diameter. They vary in length from a meter to as
much as three, but average a little more than two. Their course is often tor-
tuous, especially where roots and stones are encountered, and at the end they
are said to have two chambers, instead of the usual single cavity. These are
both lined with leaves and grass, and the male bird has on several occasions
been found in one while its mate was incubating an egg in the other. The
native lizard-like tuatara (Sphenodon) has also been known to occupy one of the
compartments, apparently without detriment to the bird in the other.
The call of Cook's Petrel, ti-ti-ti, rapidly repeated, has given it its Maori
name. When the birds come to their burrows at night, they make also a differ-
ent, gurgling sound.
Two eggs from Little Barrier Island are recorded as measuring 50 x 37 and
52 x 38.5 millimeters. Nestlings have pale bluish gray mesoptyle down on the
dorsal surface, with the ventral surface white. The egg is laid during early
November, and fledglings leave the nesting ground in March.
The above is taken mainly from Mathews and Iredale (1921, 38), Oliver
(1930, 144), and Falla (1934, 257), of which the first two sources represent
earlier compilations.
Falla found cephalopod beaks in the stomachs of all petrels of this species
that he examined.
Jespersen (1930, 2) notes that during the cruise of the ‘Dana’ in New Zealand
waters, this petrel was not observed to southward of the latitude of East Cape,
North Island. His accompanying map, showing the “‘southern limit for north-
ern breeding species’’ accordingly places the border of the pelagic range of
Pterodroma cookii at about latitude 38° S. It is well, therefore, to call attention
to the fact that I had already recorded specimens of the New Zealand race from
latitude 47° S., longitude 175° E., a point far south of the Chatham Islands
(Murphy, 1929, 3). These birds were captured during February. The point is
on a line which would strike the South American coast about halfway between
Chiloé Island and the Strait of Magellan, a region in which the breeding
grounds of Pterodroma cookii orientalis should be looked for.
MAS ATIERRA PETREL
Pterodroma cookii defilippiana
Aistrelata defilippiana Giglioli and Salvadori, 1869, Ibis, p. 63 (off northern Chile).
Names: Also called De Filippi’s Petrel.
Characters: Distinguishable from Prerodroma cookii cookii, and from all other forms of the
species, by the great depth and robustness of the bill, and the exceptional length of the tail. The
color of the feet seems to be as in typical cookii and in orientalis, with the tarsi and upper third of
the two inner toes light blue.
718 OCEANIC BIRDS OF SOUTH AMERICA
The depth of the bill of defilippiana, in front of the nostrils, ranges from 8-8.5 mm., and the
width of the maxilla at the base from 11-12 mm. In P. c. orientalis the respective measurements
are: depth 6-6.8, width of maxilla 9.5 mm.
10 adults of both sexes: wing, 229-241 (235); tail, 97-108 (102); exposed culmen, 28.5-29 (29);
tarsus, 29-31 (30.2); middle toe and claw, 34-37 (35.5) mm.
Young: The only nestling I have seen is a mummy of a chick found at Santa Clara Island, on
January 20, 1914. It has lost most of its faded bluish gray down except on the flanks and the sides
of the breast. We have also two fledglings, recently out of the nest, from San Felix Island. A little
pale gray down gtill clings to their plumage, which seems to be indistinguishable from that of
adults.
Two eggs from Santa Clara Island, Juan Fernandez, measure 48 x 35 mm. (Lénnberg, 1921, 14).
A third obtained by Beck is dull white and measures 48.5 x 35 mm.
Distribution: Breeding at Mas Atierra and Santa Clara (but not Mas Afuera), of the Juan
Fernandez group, and at San Felix Island. Ranges, chiefly well offshore in the Pacific from the
latitude of Juan Fernandez to that of central Peru. Specimens recorded from northern Peru by
Wetmore (1923, 171) prove to be Pterodroma cookii orientalis.
This very distinct petrel was first taken during the cruise of the ‘Magenta,’
and was described as a full species in 1869. Giglioli and Salvadori state that
it followed their ship to a point ‘‘not far from the Peruvian coast,’ but the
longitudinal positions of their track show that they remained at all times
hundreds of kilometers from the continental shore, and well outside the actively
upwelling zone of the Humboldt Current. Furthermore, the sight identifica-
tions of these observers are not to be trusted in view of their lack of knowledge
of this and related petrels at the time. Thus Salvadori states that Pterodroma
leucoptera was not seen during the cruise of the ‘Magenta,’ whereas we now know
that this vessel spent much time within the common oceanic range of at least
three petrels between which that author could hardly have discriminated in
the field, namely, P. leucoptera masafuerae, P. cookii orientalis, and P. cookii
defilippiana.
During the cruise of the ‘Alert,’ Coppinger (1884, 86) found this petrel
nesting at San Ambrosio Island, in July, 1879. I have examined a male he
collected on its nest, which, he says, consisted of a few twigs and feathers in a
rock crevice.
At San Felix the ‘Zaca’ party collected four adults and two fledglings on
February 18, 1935. These agree completely with Mas Atierra specimens. Dr.
Chapin’s notes state that only two were sighted over the water on the morning
of the landfall, and not many at the island itself. Both the chicks found had
already left the nest, but gray down and bird bones were discovered in weathered
niches on the slope of the Cerro Amarillo. One adult was seen to fly in and out
of the cave near the landing place. The stomachs of the specimens contained
whole squids 8 to 10 centimeters in length, mandibles and crystalline lenses of
the same creatures, and remains of small fishes. Not a petrel of this species
was obseryed near San Ambrosio, which proved to be the headquarters of the
larger Kermadec Petrel.
Lénnberg (1921, 14) reports upon the observations of Backstrém at Juan
Fernandez. During his first visit to the islands, between December and April,
the Swedish naturalist did not see this petrel. When he returned in August,
MAS ATIERRA PETREL 719
however, it had become plentiful. On August 9, 1917, he found examples nest-
ing, with neither burrows nor nest linings, beneath the edges of large boulders
along the shore of Santa Clara Islet. Two eggs were collected on that date.
Residents of Mas Atierra informed him that eggs would become more common
in September.
During the Brewster-Sanford Expedition, Beck found evidence that the Mas
Atierra Petrels occupy both the main island and Santa Clara or Goat Islet. In
January, 1914, he saw remains of old nests on Mas Atierra. On the 19th of the
month he visited a breeding site on Santa Clara and picked up one addled egg
left over from the previous breeding season. This was under an overhanging
rock in a talus heap, and about 70 meters above the ocean. Numerous bodies
of young and old birds were also among the stones. All of the adults killed
during December and January had small gonads, showing that the egg-laying
period had long passed by.
During the same season Beck took many specimens at sea around Juan
Fernandez, and between there and the continent. In June of the preceding year
he had obtained others as far north as the latitude of Ancén, Peru, but at least
80 kilometers from the coast. They were more common 250 kilometers offshore.
The pelagic range of P. c. defilippiana is thus extended much to the northward of
previous records. Many of the specimens were collected in company with
examples of P. c. orientalis but the two proved easily separable in the hand,
though probably not in the field.
On March 31, 1914, Beck observed petrels having the appearance of this
form fishing well out at sea a little north of Anctid, Chile. He could be certain,
however, only that they represented,a small species of Prerodroma.
In the scanty information we have about the life history of this petrel, the
most interesting item is that it is a surface-breeding bird, whereas its New
Zealand relative is a burrower. Other examples are not wanting among the
Procellariiformes to indicate that breeding habits, no less than morphological
characters, may be subject to seemingly abrupt, and often surprising, germinal
variations.
The length of the nesting period of P. c. defilippiana agrees with that of P.
c. cookiz, but in the case of the former the half-year of incubation and feeding
young begins in August, while the New Zealand form lays its egg three months
later.
MAS AFUERA PETREL
Prerodroma leucoptera masafuerae
Pterodroma (AEstrelata) cooki masafuerae Lonnberg, 1921, in Skottsberg’s Nat. Hist. Juan Fernandez and
Easter I., 3, Zool., pt. 1, p. 14 (Mas Afuera Island, Juan Fernandez).
The typical race of this petrel was described from Australia, the reference being as follows:
Procellaria leucoptera Gould, 1844, Ann. Mag. Nat. Hist., 13, p. 364 (Cabbage Tree Island, Port Stephens,
New South Wales).
Names: White-winged Petrel. In the literature this form has often been listed as cooki#, as was
done by the original describer.
Characters (of the species /excoptera): Sufficiently defined on p. 713, in comparison with those
of P. cookii.
720 OCEANIC BIRDS OF SOUTH AMERICA
Adults, of the typical race, P. Jeucoptera leucoptera (sexes alike): Forehead and greater part of
lores, white, but freckled with a few black-centered feathers, especially along the mid-line from
the bill to the anterior border of the crown, where the transition to dark plumage is abrupt;
circumorbital region, except for a narrow white infraorbital stripe and a variable amount of speck-
ling in front of the eye, sooty black; crown, and a definite mantle which includes the nape, anterior
part of the interscapular region, sides of neck, and a large and conspicuous patch at the side of
the breast, sooty black; back and upper tail coverts, close to light neutral gray, each feather with
a faintly discernible dark shaft streak and, in fresh plumage, a narrow white terminal margin; a
large, more or less triangular sooty black patch on the rump; wings, blackish brown G3), with a
pointed, wedge-like white or mottled white area on the inner vanes of the quills, usually less
definite and less extensive than in P. cook:i cookii; greater coverts and secondary quills, neutral gray,
externally margined with white; tail quills, neutral gray, the central pairs with sooty terminations,
the outer pairs mottled gray and white, much as in P. cookéz cookii; entire ventral surface, from chin
to lower tail coverts, white; wing-lining, white, with the anterior margin mottled as in P. cookii
cookit.
Subspecific characters of P. leucoptera masafuerae: Distinguishable from Prerodroma leucoptera
leucoptera as follows: size slightly smaller, excepting the tail, which is apparently longer than in
the typical race; crown less blackish, and the dark coloration more restricted, terminating rather
sharply at the nape, whereas in typical Jewcoptera it extends caudad into the scapular region and
very definitely into the patch at the sides of the breast (in masafuerae the latter areas are distinctly
gray rather than sooty black); white feathering extending much higher on the forehead, usually
terminating in a line drawn through the center of the eyes, some specimens having practically
clear white foreheads (in the typical form the extreme breadth of the whitish forehead, measured
from the base of the culminicorn, is about 12 or 13 mm.; in masafuerae it averages about 23 mm.);
the tarsi are grayish black, instead of flesh color.
10 specimens of both sexes: wing, 216-230 (221); tail, 97-105 (100); exposed culmen, 24-26 (25);
tarsus, 27-30 (27.2); middle toe and claw, 34-37 (36.4) mm.
Distribution: Known only from Mas Afuera Island, where it breeds, and the waters around
the Juan Fernandez group.
During the course of the Brewster-Sanford Expedition, Beck collected an
excellent series of these petrels in the waters around the Juan Fernandez Islands,
between December 20, 1913, and February 9, 1914. Although as a breeding
bird the form is known only from Mas Afuera, it proved to be common close
to the coast of Mas Atierra Island, mingling with species which nest at the
latter locality.
Owing to continual rough seas, Beck was unable to land at Mas Afuera, as
Fic. 63. Heads of two species of small gadfly petrels inhabiting the Juan Fernandez Islands.
Left, Prerodroma cookii defilippiana (breeding at Mas Atierra, the neighboring islet of Santa
Clara, and also at San Felix Island); right, P. leucoptera masafuerae (endemic at Mas Afuera).
MAS AFUERA PETREL 721
has been stated in the narrative of the expedition published in Part I. Con-
sequently he obtained none of these petrels at their nests. Among the specimens
collected at sea during December there was evidence that the breeding season
had not long passed, because the abdomens of some had bare brood-patches,
even though their gonads were reduced in size.
Lénnberg (1921, 14) reports upon examples taken by Skottsberg and Back-
strom at Mas Afuera in February, 1917, and gives a partial account of the breed-
ing habits, although he describes neither eggs nor chicks, which seem to be
still unknown. He states that this bird nests only in the highest parts of the
southern half of Mas Afuera. The burrows resemble those of the larger resident
petrel, Pterodroma externa, but are much shorter. They are found only in dense
fern groves, especially among masses of the roots and fallen stems.
In this petrel, therefore, as in the case of the Mas Atierra Petrel, the breeding
habits seem to have departed widely from those of the Old-World representative
form. In the present instance, however, it is the American subspecies which 1s
a burrower, while the Australian race is said to nest merely among crevices of
a stony surface densely covered with vegetation. Perhaps, in certain instances
the type of terrain, as determined by relative dampness, hardness, texture,
and plant cover, is sufficient to control the type of nest that a petrel uses.
Nevertheless, since a proclivity to burrow is presumably instinctive and
heritable, one would expect the trait to show up at least sporadically under
favorable circumstances, unless in the course of evolution it had been entirely
eliminated.
According to Mathews (1912, 17), the typical subspecies of P. leucoptera nests
at Cabbage Tree Island, New South Wales, in December. Selecting sites on
high ground well covered with growths of cabbage palm and vines, the birds
here lay their eggs under overhanging rocks or in crevices between stones well
concealed by forest litter. Sometimes a call-note from under a mass of fallen
fronds will lead to the discovery of an incubating bird among the stones
beneath.
The large series of P. c. masafuerae in the American Museum exhibits a wide
variation in plumage, which seems to be correlated with moult and wear.
Thus December specimens have very gray backs, scaled with white feather
edgings. The line of demarcation between the back and the darker gray of
crown and nape is very sharp. Through the effect of abrasion the white margins
on the back disappear rapidly, so that they show scarcely at all among birds
collected during February or late January. The back becomes progressively
spotted with black, owing to the appearance at the surface of the dark feather-
shafts as the distal margins of the feathers wear away; for the same reason the
line of demarcation between nape and back becomes less distinct. Variation is
also great in the relative whiteness of the forehead, the speckled area being
more extensive in some specimens than in others. Again, the tail quills also
vary widely, those of some birds being clear gray even to the outermost, while
in others the outer pairs are heavily speckled. The central rectrices are prac-
tically black distally.
722 OCEANIC BIRDS OF SOUTH AMERICA
WHITE-THROATED PETREL
Pterodroma leucoptera brevipes
Procellaria brevipes Peale, 1848, U. S. Expl. Exped., 8, pp. 294, 337 (Lat. 68° S., Long. 95° W.,"’ probably
an error for a tropical Pacific locality; see below).
Names: This petrel appears in the literature under many synonyms, including cookéi, leucoptera,
torquata, desolata, and aneiteimensis.
Characters: Smaller than any of the other races of P. Jeucoptera, except in length of tail, in
which it equals or slightly exceeds the typical form; occurs in two phases, of which the gray is
diagnostic; white-breasted examples are distinguishable from other subspecies by one or more of
the following characters: primary quills entirely dark; white forehead very narrow; a tendency
toward fine, dark gray peppering of the white ventral plumage, apparently always present at the
sides of the breast, and extending in many specimens as a band across the breast and along the whole
length of the flanks. In fact, the varying density and extent of this dark speckling produces every
stage of intergradation between white-breasted and gray-breasted phases of the subspecies. Tarsi
and upper part of the feet flesh-colored in nestling birds, and blue in adults, the distal parts of
webs and toes being black. The long mesoptyle down of chicks is plumbeous gray on the dorsal
surface and whitish on the ventral surface.
13 adults from the Fiji and New Hebrides Islands, western South Pacific (sexes alike): wing,
207-226 (218); tail, 91-99 (95); exposed culmen, 22-26 (24.3); tarsus, 26-28 (26.5); middle toe
and claw, 32-35 G4) mm.
Distribution: Tropical South Pacific; breeding at Melanesian islands, such as members of the
Fiji and New Hebrides groups, and ranging northward and eastward to the vicinity of the Gala-
pagos Islands.
The only claim that this petrel has to a place in the South American region
is based upon the capture of eight specimens by Beck during the course of the
Galapagos Expedition of the California Academy of Sciences (Loomis, 1918,
93). This was on June 11, 1906, in latitude 4° 20’ S., longitude 93° 30’ W., a
position about 5 kilometers southwest of the nearest point of the Galapagos
Islands. Many small flocks were seen moving about on the date of the record.
Loomis has compared the specimens with the type of the race in the United
States National Museum. The measurements which he publishes agree closely
with those of American Museum birds from breeding grounds in Fiji, etc.
Next to nothing is known about the life history of this petrel. Examples
have wandered far from their proper range in the tropical zone of the Pacific,
and one has been captured off the coast of Wales! I have remarked elsewhere
(Murphy, 1929, 15) that it is odd that the alleged type locality of Peale’s
‘‘Procellaria brevipes,’’ which is near Peter Island in the eastern South Pacific,
south of the antarctic circle, had not long since been questioned. Peale’s pub-
lished remarks are as follows: ‘‘Two specimens were shot on the 21st day of
March, in latitude 68° S., longitude 95° W. . . . The labels having been dis-
placed after the specimens were sent home, the sex cannot be given with cer-
tainty now, but they are believed to be males.'’ This comment, written some
years after the reported capture of the specimens, is enough to throw doubt on
all of the data. The race is unquestionably equatorial in its normal distribution,
even though a record made in the antarctic may be no more remarkable than
the one made in the British Isles.
BLUE PETREL 723
BLUE PETREL
Halobaena caerulea
Procellaria caerulea Gmelin, 1789, Syst. Nat., 1, part 2, p. 560 (Southern Ocean, latitude 48°-58° S.).
Names: By sailors not distinguished from the prions, and consequently called ‘‘Whale-bird”’
(Green, 1887, 31). In the Falkland Islands, this petrel is known as the ‘'Fire-bird’’ because of its
habit of flying into a light or bonfire at night. The name, however, is a loose one, sometimes being
applied to other species as well. Synonyms of the specific names are forsteri, similis, murphyi, and
possibly several others.
Characters: Distinguishable from all other petrels by the white tips of the central tail quills;
differs from the species of Pachyptila in the shape of the tail, which is nearly square instead of
cuneate. Halobaena is closest in appearance to Pachyptila belchert, from which it differs in having a
distinctly white, even though slightly mottled, forehead, and in lacking the pronounced white
post-orbital stripe. Furthermore, in Halobaena the crown of the head is of a much darker color
than the back, a condition approached only in the Broad-billed Prion.
Adults (sexes alike): General color of the dorsal surface bluish gray (very close to the deep
gull-gray of Ridgway), except for the crown of the head and the nape, which are much darker and
somewhat brownish; the longer scapulars are also subterminally sooty, with narrow whitish
terminal borders; marginal and lesser wing coverts brownish black, the greater series very narrowly
edged with whitish; bastard-wing and primary coverts blackish, the four outer primaries externally
blackish brown, their inner webs more or less hoary white; inner primaries and secondaries of the
color of the back, with darker shafts, the secondaries tipped and externally edged with whitish;
lower back, rump, and upper tail coverts like the back; rectrices similar but slightly more dusky
on the central feathers, and lighter or mottled with white on the outer quills, the outermost pair
being almost entirely hoary white except for the shafts; tail with a terminal white band, which is
broad and conspicuous on all save the two or three most lateral quills; crown, nape, and hind neck,
as well as the sides of the latter, brownish gray, a hue extending around the eye, beneath and behind
which it is slightly mottled with white; forehead, lores, sides of face, and ear coverts white, the
region between the forehead and vertex being mottled because the feathers have blackish centers
and white margins, producing a scaled effect; ventral surface white, the sides of the chest and
upper breast being bluish gray like the back; under-wing and axillaries white, except along the
partially dark border. Iris brown; bill blue, with the culmen and nasal tubes black, and the rami-
corn of the mandible gray; tarsus and toes blue, the webs whitish or flesh color, with central
reddish areas due to the network of blood vessels, and gray borders; claws blackish.
4 adults, of which 1 is a male, 1 a female, and 2 not sexed (2 from the South Atlantic and 2 from
Kerguelen Island): wing, 209-217 (211.5); tail, 82-89 (84.4); exposed culmen, 25-26.5 (25.6);
width of bill of one specimen, 10.6; tarsus, 32-34 (33.1); middle toe and claw, 41.2-43 (42.3) mm.
Length in the flesh of 6 Kerguelen specimens, 273-317; wing-expanse, 641-695 mm. (Kidder,
1875, 34).
Young birds may be recognized by a less cinereous or bluish gray tinge of the upper parts,
which tend more or less strongly toward brownish; the forehead, moreover, is not pure white
but is mixed with an ashy hue (Coues, 1866, 164). The nestling is covered with slaty down, the
region about the base of the bill being largely bare.
The egz. which is variable in shape, as among most petrels, has a thin, homogeneous shell
with a finely granular surface without color markings. Measurements from various sources,
chiefly from eggs taken at Kerguelen Island, fall within the following ranges: 44 x 32, 49 x 38 mm.
Distribution: Circumpolar and widespread in the west-wind zone of the southern oceans,
breeding at the Falkland Islands and at Kerguelen Island. Dabbene (1923, 126) indicates that the
limits of the known flight-range are as far apart as latitudes 33° and 70° S.
Halobaena, the Blue Petrel, has usually been grouped with the whale-birds
of the genus Pachyptila, but there seems to be little beyond a superficial resem-
blance to indicate such particular relationship. The cobalt blue of bill and feet
724 OCEANIC BIRDS OF SOUTH AMERICA
add to the resemblance, but in the conformation of the bill, in the long wing
which out-measures that of any Pachyptila of equal size, and in the general
plumage-pattern, including the scaled appearance of the feathers on the fore-
head, etc., the Blue Petrel bears a closer resemblance to the smaller petrels of
the genus Pterodroma. Most of the latter have cuneate tails but so do the whale-
birds; the squarish tail of Halobaena is sui generis.
Although the Blue Petrel has an enormous range, and is reported from many
parts of the southern oceans all around the globe, it is a surprisingly rare bird
in collections. During the course of the Brewster-Sanford Expedition, Mr.
Beck collected a single male in breeding condition over the ocean to eastward
of the Falklands. This was taken on September 20, 1915, during very stormy
and drizzly weather, and he was unable to capture a second. About a week
later, he saw many others in waters east of Staten Island, and subsequently
within sight of the north coast of that little-investigated locality.
The pelagic wanderings of this species, according to Vanhéffen (1901, 315),
are limited on the north by the boundary of the zone of westerly winds and on
the south by pack-ice. Gain (1914, 155) saw three examples in latitude 61° 23’
S., longitude 116° 56’ W., which is a long way west of the South Shetland
Islands and not far from the position ascribed to the mythical Dougherty Island.
Again, in latitude 56° 52’ S., longitude 102° 30’ W., he encountered the birds
in numbers on January 27, and from this point eastward he saw them as far as
Cape Pilar, at the entrance of the Strait of Magellan. Paessler (1913, 43) found
the species along the Chilean coast during the winter, up to latitude 35° S.,
which is north of Talcaguano. In November he met it again in flocks off Santa
Maria Island and, in July, throughout a long stretch of the South Atlantic
between the Strait of Magellan and the Rio de la Plata. Beck’s experience
shows that the Blue Petrels are to be found plentifully in this region and,
according to Gould (1865, 457), they are usually in evidence about midway
between the Tristan da Cunha group and the coast of South America. Farther
eastward in the Atlantic, Vanh6ffen (1901, 310; 1905, 503) picked up examples
not far from the Cape of Good Hope, and in the months of November and De-
cember they followed his ship, the ‘Gauss,’ southward from the vicinity of
Bouvet Island. During the British National Antarctic Expedition of 1901-1904,
Wilson (1907, 104) noted the first Blue Petrels in latitude 45° S., longitude 48° E.,
on October 24, when a heavy sea was running before high winds. From this
date the birds were continually with the vessel until it had penetrated well
into the pack-ice. On the homeward voyage the Blue Petrel was seen between
latitudes 60° and 55° S. in the Pacific west of Cape Horn, and again in the South
Atlantic. The ‘Scotia’ naturalists captured specimens as far south as latitude
69° S. in Weddell Sea, and observed birds believed to be of this species in latitude
71° 28’ S. (Clarke, 1913, 264). In the log of the ‘Scotia,’ however, the Blue
Petrel was not generally distinguished from the prions. Since it flies con-
stantly in company with the latter, its identification involves close observa-
tion of the tip of the tail, which is white in the Blue Petrel and black in all
whale-birds.
BLUE PETREL 725
Since the Blue Petrel nests at the Falklands and Kerguelen Island, I am in-
clined to believe that it does not inhabit such ice-covered antarctic islands as
South Georgia and Bouvet. Mathews (1934, 171) states that it is not resident
at Macquarie, which had formerly been credited as a nesting station. Much
misinformation on this subject seems to have crept into the literature. There
is no good reason for including South Georgia within the breeding range, since
the example from Stromness Bay of that island, said to have been obtained
during the summer of 1913, was presented to Brooks (1917, 146) from a miscel-
laneous collection of curios at Port Stanley, Falkland Islands. The specimen
may well have been captured at or near South Georgia, the waters about which
are frequented by numerous sea birds which certainly do not nest at the island.
Since then, several Blue Petrels have been seen on the wing off the entrance to
Cumberland Bay, on November 30, 1926, but the species has not been found
breeding locally. Bennett (1926, 316) states that Blue Petrel colonies are to be
found at ‘selected spots’’ at the Falklands, but he names none. There is no
doubt, however, of its place in the Falkland avifauna, and it probably inhabits
also Staten Island and some of the exposed islands along the windward coast of
Tierra del Fuego.
Most of what we know about the breeding habits of the Blue Petrel has been
recorded at Kerguelen, and appears in the writings of Kidder (1875, 34) and
Eaton (1879, 142). The birds inhahit slopes not far from the shores of that
island. Such hillsides seem deserted during the day, but become perfectly alive
at dark, with these birds and other petrels flying irregularly about and filling
the air with their calls. Halobaena seems to be the latest of the petrels to issue
above ground after nightfall, when its calling becomes incessant, ringing out
both from the air and from the burrows. The note much resembles the cooing
of pigeons, kik-kizk-kitk coo-coo. Eaton states that, while this note is very similar
to the song of the species of whale-bird that nests in the same territory, the
flight-calls of the two are quite different. During September the Blue Petrels
keep flitting about in the neighborhood of their burrows, alighting here and
there, and then taking wing again like swarms of bats. Such restlessness seems
to be very characteristic of many courting petrels; in the same manner the
Snow Petrel (Pagodroma) flits about ice-covered slopes on the coast of the
antarctic continent. After the middle of November, a reduction or cessation
of the loud night calling of the Blue Petrel indicates that its pairing season
has passed.
The burrows of Halobaena at Kerguelen are excavated beneath clumps of
Agzorella, and since they are mostly in soft dry ground, eggs can be taken without
‘much trouble. About the size of a man’s wrist in diameter, the tunnels run
straight inward for a distance, turn to the right or left, and then slope downward
to an enlarged cavity lined with fibers, leaves, or twigs. The mated pair is to
be found in the nest-chamber until the egg is laid. The first egg was discovered
by Kidder on October 23, and the first young bird on November 12, which
indicates that the beginning of the egg-laying season must extend back into
September. Eaton collected a full-fledged nestling on February 9.
726 OCEANIC BIRDS OF SOUTH AMERICA
When Kidder set adults free in the daytime, he observed that their mode of
flight was highly erratic, as if they found the light confusing. They always
came down on the water after flying offshore. Werth (1925, 588) found, by
keeping several living examples in captivity, that they would hide quietly in
the corners of boxes throughout the day, but at night would scuffle about in
lively fashion. Since they would take no food in captivity, they soon died.
Stomachs examined by this observer contained beaks of cuttlefish and remains
of small crustaceans. Some of the adult birds disgorged a green fluid or paste.
THE STORM PETRELS
SUBFAMILY HYDROBATINAE
Despite the obvious similarities among all the small storm petrels, the
members of this group were formerly divided into two families. One of these,
centering about the genera Hydrobates and Oceanodroma, was considered to be
closely related to the larger petrels, while the second group, represented by such
long-legged forms as Oceanites, Fregetta, and Pelagodroma, was regarded as a very
distinct family, the Oceanitidae. Such a system of classification necessarily
attributed to convergent evolution the similar black-and-white pattern and the
general resemblance in habits between, for example, Wilson’s and Leach’s
Petrels.
Such an academic division was not without an alleged anatomical basis,
which had been studied by Garrod, Forbes, Salvin, and other able authorities.
Lowe (1926, 1433) has reviewed the whole subject, offering a critique of earlier
classification, and presenting new information on deep-seated cranial characters.
His conclusions go to show that many of the morphological distinctions among
the storm petrels are of exceedingly slight or doubtful importance, and that
even such ponderable differences as the number of secondary remiges, the rela-
tive proportions of wing and leg bones, and the number of cervico-dorsal verte-
brae, lose weight when we take into consideration the fact that Forbes and
other investigators had not examined a number of species which might have
altered their conclusions.
Lowe decides, in short, that no taxonomic line of cleavage should be drawn
through the more or less divergent but apparently primitive or generalized
petrels known collectively as Mother Carey's chickens. He returns, rather, to
the pioneer classification of Coues, a step which I believe to be in harmony
with our still very limited knowledge of this group of birds. Finally, it should
be pointed out that the petrel which has been known as Oceanodroma melania is
a long-legged member of the so-called short-legged group, and to this degree it
makes a connecting link between the two branches of the family. Mathews
has recently given it generic status, under the name Loomelania, a step which
is no doubt well warranted (cf. p. 744).
The Mother Carey's chickens belong to all oceans and zones. As regards
migratory movements, they are of exceedingly diverse habit, a few forms being
Ho Mi /
Nil ae)
null f
y |
\
hi} ”
a
Fic. 64. Dorsal and ventral aspects of six genera of Storm Petrels, to illustrate patterns and
proportions.
Reading downward: left row, Oceanodroma leucorhoa, Loomelania melania, Oceanites oceantcus;
right row, Garrodia nereis, Fregetta tropica, Pelagodroma marina.
{ 727 ]
728 OCEANIC BIRDS OF SOUTHFAMBERIGA
apparently bound closely to areas of surface water of uniform physical character-
istics, while others, such as Oceanztes oceanicus, travel annually across the pan-
tropical oceans from the antarctic south to the sub-arctic north. The breeding
grounds of certain forms are highly restricted with relation to the climatic
zones, while certain other species, such as Oceanodroma castro, nest throughout
a very broad latitudinal range which includes such unlike insular environments
as the Azores, Madeira, the Cape Verdes, Ascension, and St. Helena. A par-
ticularly large number of species are confined to the littoral waters along
the west coast of the Americas. These include petrels of widely varying
appearance and water-temperature predilections, such as Oceanites gracilis,
Oceanodroma tethys, Oceanodroma macrodactyla, Oceanodroma markhami, Loome-
lania melania (erroneously recorded from the Asiatic side of the Pacific),
Oceanodroma homochroa, Oceanodroma hornbyi, Oceanodroma furcata, and Halocyptena
microsoma.
All of the Mother Carey’s chickens seem to have many traits in common as
regards nesting habits, although our knowledge of even the best-known species
is no more than casual and fragmentary. Much pleasant literature has been
written regarding their courtship, night singing, etc., but there is a great dearth
of objective description concerning just what takes place in the reactions and
behavior of these primitive and extraordinarily interesting birds. Many prob-
lems remain to be worked out, for example, in connection with the place of
the sexes in incubation. It seems likely that the male of certain species has
more to do with the hatching of the egg than the female, and that males in
general show the more pronounced development of the bare brood-patch on the
belly. The majority of specimens that have been captured upon the egg seem to
be males, although the data are more or less conflicting. The size relationship
of the sexes also deserves further investigation, for among some species the
females are consistently larger, as is true in the case of boobies and certain
other Pelecaniformes.
All of the storm petrels probably have nocturnal habits at sea no less than
at their nesting grounds. Coppinger (1884, 88) and Green (1887, 21) have long
ago pointed out that from a ship twice as many may be captured at night as
during the day by means of weighted threads trailed from the taffrail. More
than any other ocean birds, too, they sometimes ‘‘rain’’ on board ships at night,
being misled by the lights, especially in foggy weather.
Additional collecting of storm petrels is needed in several parts of the world
in order to settle numerous problems of distribution and subspecific relationship.
We need still more, however, an exhaustive study of the life history of any
single species by an observer or group of observers prepared to camp at the
nesting ground before the date of arrival of the first birds, and to keep a detailed,
matter-of-fact account of their mysterious comings and goings and their mutual
reactions and territorial, social, and parental behavior during the extraordinarily
long period between the beginning of the courtship and the exodus of the
whole population.
LEAST PETAR EL 729
LEAST PETREL
Halocyptena microsoma
Halocyptena microsoma Coues, 1864, Proc. Acad. Nat. Sci. Phila., p. 79 (San José del Cabo, Lower California).
Names: There are apparently no synonyms of the specific name.
Characters: Small size, the wedge-shaped tail, and the uniformly dark color, without any white
areas, should distinguish this petrel from any other occurring within the same range.
Adults (sexes alike): Sooty black, the ventral surface slightly browner, the greater wing
coverts paler and forming a wing-patch; quills of wing and tail black; under wing coverts dark
sooty brown, those around the edge of the wing forming a scarcely distinguishable black band.
Iris brown; bill and feet black.
Measurements of 11 adults of both sexes from San Benito Island, taken during the months of
July and August, are as follows: wing, 118-125 (121); tail, 50-56 (53.4); exposed culmen, 11-12
(11.4); tarsus, 20.5-22 (21.2); middle toe and claw, 17-20 (18.8) mm.
Worn claws, as if from scratching the abrasive surface of the nesting ground, result in, perhaps,
unduly small figures for the length of toe and claw. There is no determinable difference in the
size of the sexes among the specimens measured.
The young are covered with sooty or slaty black down.
Eggs: The eggs are of variable shape as in most other petrels. They are white, with a rosy
flush before being blown, and in many of them a ring of dark specks encircles one end. The pigment
of these is easily rubbed off, the slightest touch leaving a smudge. Measurements of 40 average
23.4 x 19.4, the eggs showing the four extremes measuring 28.2 x 22, 23 x 18.5 and 25.2 x 18 mm.
(Bent, 1922, 124).
Distribution: Breeds only at San Benito Island, off the Pacific coast of Lower California.
Known from the vicinity of its nesting ground, the Gulf of California, Mazatlan, Panama, and
the coast of Ecuador.
The only South American record for this relatively little-known species is
that of Salvadori and Festa (1900, 48), who captured a male and a female of
the Least Petrel in Jatitude 1° 30’ N., off the coast of Ecuador, during the
month of February. The birds flew aboard the steamship ‘Quito’ during the
night, attracted by the electric lights.
The only known breeding ground is San Benito Island, where eggs have
been taken during July, August, and early September, and newly hatched young
between August 12 and September 8. The eggs are not laid in burrows but in
bare sites under slabs of rock, or in the crevices and niches of ledges where only
subdued light can reach the incubating bird. The call-notes of the Least Petrel
are said to resemble the whirring of a rapidly revolving cogwheel (Anthony,
1925, 285).
GALAPAGOS STORM PETREL
Oceanodroma tethys tethys
Thalassidroma Tethys Bonaparte, 1852, Beilage no. 7, Tagebl. Deutsch. Naturf. und Aerzte, Wiesbaden,
p- 89 (Galapagos Islands).
Names: This species has apparently always been listed under its correct specific name.
Characters: Very similar in appearance to the European Storm Petrel (Hydrobates pelagicus),
but with a forked instead of a square tail and with all white instead of black-tipped upper tail
coverts. In consequence of the latter condition, the white rump of the Galapagos Storm Petrel
is triangular rather than nearly rectangular.
Adults (sexes alike): Sooty black, with a slight plumbeous gloss in fresh plumage, the ventral
surface a little less dark, or more grayish, than the back; greater wing coverts brownish (or rapidly
730 OCEANIC BIRDS OF SOUTH AMERICA
becoming so with wear) forming a wing-patch; lower rump and upper tail coverts white, with
hair-like black shafts; a small white patch at the sides of the vent; quills of wing and tail black;
entire lining of wing dark, like the breast. Iris brown; bill and feet black.
13 males and 9 females from the Galapagos Islands: wing, 129-139 (134); tail, 55-64 (59.5);
exposed culmen, 12-14 (12.9); tarsus, 21-24 (22.8); middle toe and claw, 18-20 (19.4) mm.
Downy young are entirely gray, similar to those of Hydrobates.
An egg from Tower Island, Galapagos, believed to be of this species, is inclined toward an
elliptical-ovate shape, white, with a few very minute dark dots so small and scattered as to be
hardly perceptible. It measures 26.7 x 19.9 mm. (Loomis, 1918, 153).
Distribution: Breeds at the Galapagos Islands and ranges northward through the tropical
Pacific at least to latitude 23° 32’ N., longitude 113° 4’ W., off the southern coast of Lower Cali-
fornia, and southward to at least 4° 25’ S., longitude 93° 30’ W.
The American Museum Collection contains eight males and six females of
this storm petrel from the vicinity of the Galapagos Islands, collected between
the months of January and August, and one male taken a short distance south-
west of Cocos Island on September 2. I have also examined the series in the
Berlin and British Museums, including in all specimens from six islands of the
Galapagos group. Measurements show that the typical race is consistently
larger than the next subspecies, which is confined to the Humboldt Current
region of the west coast of South America.
Most of our information regarding the Galapagos Storm Petrel is derived
from the report of Loomis (1918, 151) which records observations made during
the expedition of the California Academy of Sciences. On the voyage this
species was encountered at sea between a position off the coast of Lower Cali-
fornia, during July, southward to the Galapagos Archipelago from where it
has been reported during every month of the year. It was also found well to
southward of the Galapagos in June, 1906, but, in quoting various still more
southerly records for the west coast of South America, Loomis has gone into
the range of the well-marked subspecies of the Peruvian and Chilean littoral.
The Galapagos Storm Petrels nest in holes in the cliffs and among the lava
blocks of Tower Island, and doubtless in similar situations at many of the other
islands of the archipelago. Examples taken in April near Albemarle Island had
enlarged gonads, indicating the advent of the egg-laying season. It seems prob-
able from descriptive data on the labels that the height of the breeding period
is reached in June. The only egg obtained by the California naturalists was an
addled example found on September 15. A complete post-nuptial moult begins
among these petrels in July and is completed by October. It appears likely
that the nesting chambers are used as places of rest during parts of the year
when the birds are breeding. The same phenomenon has been observed among
other Procellariiformes at Gough Island, Tristan da Cunha, and elsewhere. It
seems to be characteristic of the sedentary or stay-at-home members of species
which ordinarily make migrations to parts of the ocean at considerable dis-
tances from their breeding headquarters.
The members of the California Academy Expedition report that these petrels
are extraordinarily silent, even when following a vessel and picking up turtle
fat or other food thrown overboard. Their flight is said to be butterfly-like and
GALAPAGOS STORM PETREL 731
more erratic than that of Lowe's Storm Petrel (Oceanites gracilis galapagoensis),
with which they associate. Galapagos Short-eared Owls are their principal
enemies so far as known, remains of the petrels being often found in pellets
regurgitated by these birds of prey.
PERUVIAN STORM PETREL
Oceanodroma tethys kelsalli
Thalassidroma tethys kelsalli Lowe, 1925, Bull. Brit. Orn. Club, 46, p. 6 (Pescadores Islands off Ancén, Peru).
Names: Known in Peru as ‘‘Danzarin,’’ though probably not distinguished from other small
species of Mother Carey’s chickens.
Characters: Averaging slightly smaller in all dimensions, particularly in wing-length, than
the typical race of the Galapagos Islands. The describer, who refers only to the shorter wing,
writes: ‘‘I think the fact that birds found along the western shores of Peru and in the neighbour-
hood of Panama appear to run smaller than the form from the Galapagos is sufficiently interesting
to be recorded, especially as exactly the same thing occurs in Oceanites gracilis.”’
Midd]
Wing Tail Culmen Tarsus a f Pi
8, coasts of Peru and Ecuador. . . 122.4 56.6 ORT 21.4 18.6 mm.
62, including the type, same localities .| 125.8 57.1 12.2 D1] 18.9
Minimum of the series. ....... 117 54 11 20 17.5
Maximum of theseries ....... 128 63 13 23 20
Chicks are clad in gray down (close to the deep neutral gray of Ridgway), the mesoptyle down
being longer and more complex than the natal coat. At all stages they closely resemble the young
of Hydrobates, the European storm petrel.
Six eggs from the Pescadores Islands, Peru, are of variable shape, ranging between short-ovate
and elongate-ovate, white, without dots or marks of any kind other than slight stains, and measure:
26.1 x 20.6, 26.6 x 19.6, 27.1 x 19.6, 28.6 x 19.6, 27.8 x 19.2, and 27.7 x 19.9 mm.
Distribution: Breeding at islands off the coast of Peru (Pescadores and San Gallan), and rang-
ing in the Humboldt Current to a distance of at least 300 kilometers from shore, between northern
Chile and the coast of Ecuador, and perhaps northward to Panama.
The type specimen of this petrel, which is now in the British Museum, is
one of a series collected by Mr. Beck during the Brewster-Sanford Expedition
at the Pescadores Islands, off Ancén, a little to northward of Callao, Peru,
between May 8 and 13, 1913. From this locality the American Museum has
breeding adults, newly hatched nestlings, and eggs. Older nestlings were
obtained at San Gallan Island, off Pisco, about two months later. Other speci-
mens were collected to westward of the coast between Callao and Cafiete, at
distances as great as 300 kilometers offshore, during the months of May and
June. On September 13, 1922, Dr. Chapman preserved four specimens which
were not in a breeding condition, and which flew aboard his steamer at night
in latitude 1° S., off the coast of Ecuador. Wetmore (1926, 52) obtained one in
the same manner to westward of La Plata Island, Ecuador, on May 9, 1921.
Dr. Lowe, the describer of the race, states that it evidently ranges at times north-
ward to Panama, where a specimen was collected during the ‘St. George’
expedition. If this is of regular occurrence, the pelagic range of the Peruvian
coastal race comes into close contact with that of the Galapagos race.
Te OCEANIC BIRDS OF SOUTH AMERICA
The differences between these two subspecies are very well marked, 0. t¢.
kelsalli averaging smaller in all dimensions than the typical form, the difference
in length of wing being especially noteworthy. In fact, the maximum wing-
length in kelsalli is less than the minimum measurement among more than 70
Galapagos specimens as recorded by Loomis.
Our September specimens from Ecuador are in fresher plumage than the
breeding Peruvian birds taken during midwinter (May-June). The former lack
the pronounced wing band, which develops with wear and results from disin-
tegration and bleaching of the tips of the greater coverts. Among some of the
incubating adults from Peru the moult of the wing quills is just beginning.
Beck first found these petrels nesting on small islets known as Guaca and
Gallinazo, of the Pescadores group, during early May. The nest sites were
situated in crevices between boulders and slabs of rock, at a distance of a half
meter or more from the chinks by which the petrels entered. No nest was
constructed, other than a slight hollow scraped in the soil and guano that had
sifted into the crack. Nests of Inca Terns and Peruvian Diving Petrels were in
close proximity among the interstices of the rock, while above several of them
boobies and cormorants were nesting in droves.
Curiously, Beck saw practically none of these petrels over the ocean in the
neighborhood of the Pescadores Islands, although Fuegian and Elliot's Petrels
were about in flocks. He encountered kelsalli chiefly while cruising a long
distance from shore. Large numbers were observed near the Hormigas de
Afuera Islets on June 4, and others still farther westward during the next week.
Beck noted that this species flies in the typical Oceanodroma manner ‘with longer
wing strokes, perceptibly slower than those of Wilson's Petre], and more like
a Night-hawk.”’ I have myself likened the flight of other species of Oceanodroma
to that of a Night-hawk (Chordeiles), as the best character by which it can be
told at long ranve from the aérial movement of Oceanites.
The chicks of this petrel are practically indistinguishable from those of
Hydrobates. The size and probable age of fledglings taken at San Gallan Island,
on July 3, when correlated with the eggs and newly hatched young found at the
Pescadores in early May, would indicate a similar rate of development. The incu-
bation period of Hydrobates pelagicus is known to be not less than five weeks, after
which the young bird remains in the nest for at least eight to nine weeks more.
Wetmore (1923, 170) has received a female Peruvian Storm Petrel taken
during the evening of November 17, 1922, at a point about halfway between
Iquique and Cobija, Chile, by Mr. Fagan, wireless operator of the S. S. ‘Santa
Elisa.’ Paessler (1914, 273) also records the race in latitude 20° 6’ S.
MADEIRAN STORM PETREL
Oceanodroma castro castro
Thalassidroma castro Harcourt, 1851, Sketch of Madeira, p. 123 (Desertas Islets, Madeira).
Names: Harcourt’s Petrel. ‘‘Andorinha das Tormentas’’ is recorded as a vernacular name in
Brazil, though it probably applies to any small petrel. ~Synonyms of the specific name include
cryptoleucura and jabe-jabe, the latter being one of the native names at the Cape Verde Islands;
melanogaster has also been used through erroneous identification.
MADEIRAN STORM<«PETREL 733
Characters: Distinguishable from Oceanodroma leucorhoa by its slightly lesser size, square tail,
and the fact that the white upper tail coverts are always black-tipped and the bases of the outer
tail feathers white. I have learned no way to distinguish these two species apart in the field.
Adults (sexes alike): Sooty black, with a plumbeous gloss in fresh plumage; upper tail coverts
white, with broad black tips, some of the center feathers with a subterminal black spor; outer tail
quills basally white; wings mostly black, but the greater coverts and inner secondaries somewhat
ashy and narrowly fringed with white; head and neck more ashy than the back; ventral surface
inclining toward sooty brown; lateral under tail coverts white, or white shaded terminally with
ashy; a patch of white feathers on the lower flanks uniting with the white under tail coverts.
Iris brown; bill and feet black.
12 males and 2 females from the Cape Verde Islands, Ascension, and St. Helena: wing, 147-
159.5 (153.7); tail, 68.4-78 (72.7); exposed culmen, 14.5-16.5 (15.5); tarsus, 22.2-23.5 (22.8);
middle toe and claw, 21-23.5 (21.8) mm.
The range in dimensions among birds from any one of the above localities is practically as great as
that from all of them. The wing-expanse of 10 examples in the flesh ranged between 440 and 495 mm.
Chicks from Ascension are clad in down of a deep mouse-gray hue. The second down is ap-
parently slightly darker than the protoptyle coat.
Two eggs from Razo, Cape Verde Islands, are pure white and measure 31 x 24 and 31 x 23.6 mm.
Distribution: Breeds throughout a wide sub-tropical and tropical belt in the eastern and central
Atlantic, including the Azores, Salvajes, Cape Verde Islands, Ascension, and St. Helena; ranging
to various parts of the coast of America, at least when transported by tropical storms, and recorded
from the vicinity of Para, Brazil. Identical or closely related petrels are found in the eastern
tropical Pacific.
The Madeiran Storm Petrel is apparently only a straggler to the coast of
America, but it has an extraordinarily wide breeding distribution among
Atlantic islands both to northward and southward of the equator, these vary-
ing, moreover, in climatic status between tropical Ascension and the north-
temperate Azores. The closest nesting station to South America is probably
Ascension, and the species has been recorded by Snethlage (1914, 77) from Para,
Brazil, upon the basis of two specimens. In Part I of this book I have discussed
the frequency with which the Madeiran Storm Petrel has been carried by
cyclonic disturbances to the southerly coasts of North America, and even to
such high latitudes as the interior of Canada.
Like so many of the other petrels, this species varies its nesting habit accord-
ing to circumstance and either burrows into soft soil or makes use of chinks
among the rocks. Both styles of nesting are represented, for example, in the
Cape Verde Islands (Murphy, 1924, 237).
During the South Atlantic Expedition of the Cleveland Museum of Natural
History, the Madeiran Petrel was collected at two South Atlantic islands,
namely, Ascension and St. Helena. At the former locality it was found breeding
on Boatswain-bird Islet, where downy chicks were taken on December 8. In
all probability an egg recorded from a rock crevice of the same locality by
’ Penrose (1879, 282) referred to this species, although that author listed it
tentatively under the name ‘‘Procellaria melanogastra.’’ At St. Helena the
Cleveland Museum party obtained nesting examples during October, and at the
Cape Verde Islands in April. Meliss (1875, 97) was doubtless referring to this
species when speaking of a small Mother Carey's chicken which lays its egg
at St. Helena in November.
734 OCEANIC BIRDS OF SOUTH AMERICA
BANGS’S STORM PETREL
Oceanodroma castro bangsi
Oceanodroma castro bangsi Nichols, 1914, Auk, 31, p. 388 (latitude 1° N., longitude 93° W., just northwest
of the Galapagos Islands).
Characters: Alleged by the describer to have a heavier and more strongly hooked bill than the
typical race of the Atlantic. The status of the form can be determined only after further comparison
of adequate series from both oceans.
27 males and females from Galapagos waters: wing-expanse, 455-485 (467); wing, 148-166 (157);
tail, 65-74 (70); fork of tail, 3-12.5 (7.8); exposed culmen, 14-16.3 (15.4); depth of maxilla, 4.5-
5.6 (5); tarsus, 19-22.4 (21); middle toe and claw, 20.1-24.6 (22.8) mm. (Loomis, 1918, 159).
The natal down of chicks is mouse-gray, the secondary down of somewhat darker tone.
Two eggs from Cowley Islet, Galapagos, are white, more or less discolored through incubation,
ovate and elliptical-ovate, respectively, and measure 32.4 x 23.4 and 33 x 21.4 mm.
Distribution: Breeds at the Galapagos, and probably at Cocos Island, and has been taken in
waters adjacent to each.
No one has yet brought together a sufficient number of specimens of Oceano-
droma castro from the eastern Atlantic, the Galapagos district, and the Hawatian
district, to determine the status of the three subspecies which have been proposed.
The species as a whole has long been pointed out as exemplifying sea-bird
distribution which antedates the latest junction of North and South America
through the uplift of the Middle American land-bridge. Such suppositions,
however, deal rather irresponsibly with enormous periods of geologic time—
going back, indeed, well into the Tertiary. To be sure, castro occupies a broad
median oceanic belt, which extends from the Azores and St. Helena on the east to
Hawaii on the west. We must remember, however, that a bird which is not infre-
quently carried by tropical storms from the eastern Atlantic to the Caribbean and
even to the interior of North America might, through similar agencies, be forced
to cross the Isthmus of Panama, and thus come to populate parts of the Pacific.
The subspecific merits of the birds inhabiting the Galapagos region can be
determined only through additional research. However, since the Pacific part
of the population seems to be extremely isolated from that in the Atlantic, it
may for the present be separately considered.
The eastern Pacific bird is known chiefly through the investigations of the
California Academy of Sciences, as reported upon by Loomis (1918, 156). The
petrels were noted in the vicinity of many islands of the Galapagos group
throughout the year. Examples with enlarged sex organs were collected during
May, and a breeding ‘colony was discovered at Cowley Islet, east of Albemarle
Island, on August 13, 1906. The eggs were deposited in slight hollows in the
soil, among boulders or inside small caverns. Downy chicks were found on
the same date.
LEACH’S PETREL
Oceanodroma leucorhoa leucorhoa
Procellaria leucorhoa Vieillot, 1817, Nouv. Dict. Hist. Nat., 25, p. 422 (Picardie, France).
Names: Fork-tailed Petrel. Synonyms of the specific name include Jeachi, bullocké and scapulata.
Characters: Probably indistinguishable over the ocean from the Madeiran Storm Petrel, from
which it differs in the pronounced forking of the tail and in that the bases of the outer rectrices
are dark rather than white.
LEACH'S PETREL 735
Adults (sexes alike): Sooty black, with a plumbeous gloss in fresh plumage, the upper tail
coverts usually, though not always, entirely white, forming a distinct patch; median and greater
wing coverts drab-brown, becoming more definitely and extensively so with wear and abrasion,
and thus producing a pronounced wing band; greater coverts and inner secondaries narrowly
margined with whitish; a few more or less white feathers on either side of the rump; quills of
wing and tail mainly black, the inner secondaries somewhat brownish, and the wing-lining some-
what ashy brown; ventral surface generally browner than the dorsal, the gray or plumbeous cast
being most conspicuous on the throat, face, and sides of neck. Iris brown; legs and feet black.
Adult birds exhibit wide variation in the amounts of white and black on the upper tail coverts.
In some birds these feathers are entirely white, while other specimens show broad dark tips almost
like those of O. castro. Some coverts are parti-colored on opposite vanes, and some show hardly a
trace of the black hair-like shafts. One of the breeding petrels from Bird Rock, Gulf of St.
Lawrence, has coverts which are nearly all dark, except for the lateral feathers; a Greenland
specimen also has a large admixture of dark feathers. Such departures from the white-rumped
condition are paralleled among the other subspecies of O. Jeucorhoaz. Among Atlantic specimens in
good plumage, the fork of the tail amounts in some instances to as much as 25 mm.
The following measurements are based upon birds from South Greenland, Newfoundland,
Quebec, New Brunswick, Long Island, N. Y., the South Atlantic (latitude 3° 15’ S., longitude
33° 40’ W.), the eastern tropical North Atlantic, and the Mediterranean.
Midd
Wing Tail Culmen Tarsus a d ee
SOUMM EPL der Reo Na hee 157 82.4 16.9 24.5 25.3 mm.
SOM te iivoks Stak cee aks we. os 156.6 78.8 17:1 24.2 24.7
Minimum of theseries. . ...... 153 76 16 23 23
Maximum of theseries ....... 164 85 17.8 26 26
Long series of figures for both Atlantic and North Pacific birds, as published by Loomis (1918,
165) and others, agree essentially with these.
The wing-spreads of four specimens taken in the tropical North Atlantic during December
measured between 438 and 470 mm.
Distribution: Breeds on both sides of the North Atlantic Ocean from Massachusetts and the
Mediterranean northward to Newfoundland, southern Greenland, and Iceland; in the Pacific on
Alaskan islands, the Aleutian, Commander, and Kurile Islands. Migrates southward in winter
across the equator in the Atlantic Ocean and the eastern Pacific.
Leach's Petrel reaches South America chiefly as a winter migrant from the
north, although it is likely that both first-year and senile birds may be found
within the tropics at all seasons. During late April, 1913, I collected and
observed numerous examples south of the equator, in waters near Fernando
Noronha and Rocas Reef. Their ‘‘springy’’ flight distinguished them even at
long range from the Wilson’s Petrels which were also about in numbers.
Furthermore, the Leach’s Petrels settled very frequently on the water, holding
the tips of their wings high while they swam about for a few moments at a time.
In the Berlin Museum I have examined a male taken midway between Fernando
Noronha and St. Paul Rocks on February 26. During October, 1912, I also
collected birds which came aboard the brig ‘Daisy’ in the tropical Atlantic,
about halfway between St. Paul Rocks and the nearest part of the African coast.
The species has been recorded from the middle of the Caribbean Sea on June 19
(Wetmore, 1923, 170), from near Barbados (Murphy, 1915, 172), and from the
coasts of British and Dutch Guiana (Chubb, 1916, 86).
736 OCEANIC BIRDS OF SOUTH AMERICA
On the Pacific side of the continent, three specimens were collected by the
California Academy Expedition to southward of the Galapagos Islands, on
June 11, 1906 (Loomis, 1918, 164). Several races of this petrel have been de-
scribed from the west coast of North America, and Loomis gives no opinion as
to which of these the southern-hemisphere examples represent. Their dimen-
sions are, however, as follows:
’ : Middle toe
Wing Tail Culmen Tarsus | ond claw
Coe Ae LES ee Sta hit ee Ricre- 150 76 17 22.3 25.7 mm.
Ce oO. Se eae, OF ae 153 75) 16.5 23.9 24.3
Cateretieae oc Ane ire: poate asaile 156 77 16.5 207s i246
These figures, allowing for the slight difference in the length of the tarsus
which I usually find between Loomis’s measurements and my own, indicate
that the birds are of the typical or northernmost race, /eucorhoa, which evidently
enters the southern hemisphere in the Pacific exactly as in the Atlantic.
I have mentioned above the distinctive style of flight of Leach’s Petrel—
distinctive, that is, of the genus rather than of the species. As I was perhaps
the first to point out (/. c., 171), this differs so strongly from that of Wilson's
Petrel that the two can be told apart practically as far as they can be seen.
This is confirmed by Wynne-Edwards (1935, 279), who states that Leach’s
Petrel does not habitually follow ships, and adds that it
. springs and bounds through the air in the strangest erratic manner, now gliding like a
miniature shearwater, now beating on buoyant wings like a nightjar, or turning with incredible
swiftness as it is caught and borne on a stronger gust down the breeze.
The studies and careful compilations of Wynne-Edwards indicate that the
Leach’s Petrels do not usually return to their breeding grounds in northeastern
North America until well into the month of May. Perhaps they linger for a
time offshore, for the early but excellent account of Ambrose (1864, 34) states
that the Nova Scotian fishermen on the route toward the West Indies were
accustomed to encounter the vanguard along the edge of the Gulf Stream during
the latter part of March. Before the end of June the birds occupy their
insular breeding stations in the Maritime Provinces and eastern New England,
in the vicinity of which they remain until September or later. At all times
they seem to be absent or scarce in the middle reaches of the North Atlantic.
Adults taken on their southward passage immediately after the end of the
breeding season are almost invariably found to be undergoing a full moult
of the quills. Replacement of the body plumage is, on the other hand,
pre-nuptial.
Much remains to be learned about the courtship and territorial relations of
the Leach’s Petrels. Research carried on during several years by Gross* and
*As this work goes into page proof, the extraordinarily-flluminating study of the life cycle of Leach’s
Petrel by W. A. O. Gross (1935, 382) appears in ‘The Auk.’ The communication becomes essential to an un-
derstanding not only of this species but of the habits and reactions of all the Mother Carey's chickens, and
of petrels in general.
LEACH S PETREL qt
others may ultimately make the species the most studied and best known of
storm petrels, but the findings have not yet become available. A point of special
interest, concerning which further information is awaited, has to do with the
fact that male birds are so frequently to be found alone in the nest-chambers
before the appearance of the egg, and that they perhaps also carry the major
share of incubation.
The nest of this storm petrel may be made among deep recesses of rocks or
excavated in soft, damp soil, sometimes in the floor of a forest-covered island,
again in a bare field or pasture. The galleries usually run more or less zigzag,
parallel with the surface of the ground, and at a depth of 15 centimeters or so
beneath it. Their course is naturally altered by obstructions such as stones and
roots. A little nest material in the form of pebbles, feathers, grass, or leaves
is sometimes used, but eggs are also commonly laid directly on the soil. Nor-
mally the members of a family come and go only after nightfall, and I have
always discovered, to my surprise, that the birds are rarely to be found by day
in waters close to their nesting grounds. Along the coasts of Maine and Nova
Scotia, Wilson's Petrels, which are migrants from the other end of the world,
may be seen during the summer in every bay and cove, as well as through a
broad littoral belt, while one may search the same waters in vain for the species
which lives on these very shores and makes the earth ring with curious sounds
at night.
In digging the burrows, according to Ambrose, Leach’s Petrel uses its bill
as a pick and then kicks the loose earth out very rapidly, working one webbed
foot after the other, and thus pressing and wallowing along with the soil
flying out behind. When the roofs are lifted from their burrows by human
hands, the birds cower back into dark corners and, if disturbed further, they
sometimes squirt the familiar oily fluid from their throats and nostrils. After
the appearance of an egg, only one petrel is to be found at the nest, the relief
between mates taking place under cover of darkness. The twittering of the
petrels below ground sounds like the squeaking of mice. It may go on through
much of the night, but it ends abruptly before sunrise. A few days after the
hatching of the chick, both parents cease to remain at the nest, coming only
at might to feed their offspring. The young Leach’s Petrels, according to
Norton (1891, 50), lie at full length in the nest-chamber, with the tip of the
bill resting on the ground and the feet extending forward beneath them. In
this position only their rapid breathing testifies that they are alive. The
protoptyle down is of grayish sooty brown, slightly paler on the ventral
surface, soft and long, covering the entire body except the lores, the region
around the eyes, and the chin and upper throat. The second down thinly
covers these areas, where it remains shorter than elsewhere; over most of
the body it inclines to be slightly darker and of closer texture than the
first down.
Norton says the adults return during incubation very early in the evening
to relieve their mates, the first nasal petrel squeaks coming just after the last
tern’s voice is hushed. The hour doubtless varies with the sun; Forbush (1928,
738 OCEANIC BIRDS OF SOUTH AMERICA
146) found on a July evening at an islet off the coast of Maine that the petrels
did not begin to return until about nine o'clock. After this, ‘tender chucklings,
crowings, stammerings and formless sounds that seemed like billing and cooing
filled the air.’ These notes, which might be called the song of greeting or
arrival, were succeeded later in the night by a different chorus, softer and more
liquid, which was probably uttered at the mouths of the burrows.
The following description by Norton (1921, 1) of a night among the breeding
Leach’s Petrels not only gives an impression of their voices, but also probably
presents a pattern of general behavior applicable to many other species of
Mother Carey's chickens about which we know even less than of this one.
Here within Night’s dominion in the midst of a no less funereally garbed throng of flitting
forms, seeming to speak most earnestly in a subhuman, unknown tongue, which is answered by
their encaverned mates in purring tones and pleading wails, the mind may readily picture a most
animated gathering of the black elves of old, hurrying to and fro for the accomplishment of some
important mission, ere dreaded Day begins . 5
The wide-ranging birds from the sea have returned to land to relieve their brooding mates,
and the air seems full of them, calling on every hand; the scene seems a hopeless chaos of activity,
but soon by careful observation it is resolved to one of orderly purpose. As each flying bird passes
over its nest, it calls in a hurried gibberish, to be answered by its brooding mate in an energetic
purr often ending with a coaxing wail; the flying bird dashes on and swings away to leeward again
coming up the wind, and again as it passes its nest calls as before to be answered again; time and
again this is repeated, each passage over the nest finding the flying bird lower and lower in its
flight, until it finally drops to the entrance of its burrow to meet its anxious mate. Now from the
dank weeds and grass, like great June bugs others are rising, or crawling to a convenient place to
rise. One is in the very midst of their activities. From one’s feet to twenty feet overhead they
swarm, often dashing against one’s person in their haste.
But with the coming of the dawn, calm, damp and chill, this strange vision of the night has
faded as a dream.
Do the nocturnal habits of these birds make them utterly strange to the
creatures of the day at their nesting grounds? Forbush noted on several occa-
sions that when Leach’s Petrels were released in the daytime on islands at which
gulls or terns were breeding, the appearance of the petrel on the wing at once
silenced their cries, and caused them to fly away. This is particularly curious,
since the presence of a hawk, an owl, or a cat will cause gulls and terns to
swarm with a great outcry to assail the intruder, ‘‘but the small and apparently
inoffensive petrel is avoided as if it were ghost or banshee.”’
Ambrose found that the musky smell of the Leach’s Petrels so permeated
Green Island, Nova Scotia, that it was perceptible even at a good distance to
windward, while light breezes sometimes carried the odor as far as 25 kilo-
meters to leeward.
Definite stomach contents of this species include small fish, copepods, am-
phipods and other crustaceans, and cinders. Elsewhere I present evidence to
show that certainstorm petrels feed actively at night. Wynne-Edwards suggests,
however, that Leach’s Petrel may be wholly diurnal while at sea, citing as
evidence a bird which fell on the deck of a ship, and which, although com-
pletely quiescent through the hours of darkness, became extremely active as
the first streaks of dawn appeared.
MARKHAM’S STORM PETREL 739
MARKHAM’S STORM PETREL
Occeanodroma markhamt
Cymochorea markhami Salvin, 1883, Proc. ZoG]. Soc. London, p. 430 (latitude 19° 40’ S., longitude 75° W.,
off Pisagua, Chile).
Characters: An ‘‘all black" storm petrel G@. e., without a white rump); difficult to distinguish
in life from Loomelania melania, from which it differs chiefly in having a much shorter tarsus.
Adults (sexes alike): Dorsal surface sooty black, with a pronounced plumbeous gloss on the
head, neck, and mantle, in fresh plumage; ventral surface, caudad from the neck, and wing-lining
blackish brown, becoming almost fuscous with wear of the plumage; scapulars narrowly edged
externally with whitish; most of the wing coverts hair-brown, the external edges rapidly whitening
with wear, producing a conspicuous and broad grayish bar which usually extends much closer to
the wrist or bend of the wing than the somewhat similar mark in Loomelania melania; upper tail
coverts grayish basally and with white shafts for half their length (unlike the condition in Loome-
lania). Iris brown; bill and feet black.
Measurements of 12 specimens are as follows:
Wing Tail Culmen Tarsus Pee
60, coasts of Chileand Peru... . . 172.7 92.7 18 23.9 25.6 mm.
Sie yCOaStiOMPerul., © 4 a ac ce heea: 169.8 89.4 18.1 24.2 25.1
2, Type, off Tarapaca, Dec., 1881 . . 175 92 1S) 25 24.5
Minimum of the series. ....... 163 87 16.8 23 23
Maximum of theseries ....... 181 97 19 25 25
The fork of the tail in birds of good plumage ranges from 30-34 mm.
An egg taken from a bird shot over the ocean 75 to 80 kilometers west of Huacho, Peru, on
June 13, 1913, is pure white, smooth-surfaced but without gloss, and measures 34 x 23.9 mm.
Distribution: Coastal and offshore waters of Peru and Chile, to a distance of at least 300 kilo-
meters from the coast; occurring regularly in the Humboldt Current between latitude 33° S. and
northern Peru, and known to migrate into the North Pacific as far as the vicinity of Clipperton
Island. Breeding ground unknown.
Present knowledge about Markham’s Storm Petrel is highly anomalous. We
are, for example, well acquainted with its range at sea. We know from the
collections and notes of Mr. Beck that its breeding season comes during the
southern-hemisphere winter, for the females he shot in latitudes close to that
of Callao, during the first half of June, 1913, were at the point of laying eggs,
and both sexes were, characteristically, undergoing a moult of the quills at the
same time. One example taken far offshore on June 13 contained in its oviduct
an egg ‘ready to lay to-night,’’ as Beck expressed it on the label. This egg,
with a completely formed shell, is the one I have described and measured, as
noted above. Yet despite the fact that we have a fully labeled egg of this
petrel, and all of the other data just mentioned, the whereabouts of its nesting
grounds is still wrapped in a mystery which is deepened, rather than clarified,
by Beck’s discovery.
Most of the islands off the Peruvian coast have been thoroughly examined,
the only exception being the little cluster called Hormigas de Afuera which
lies 67 kilometers to westward of Callao, with its ledges rising not more than
8 to 9 meters above the level of the ocean. It seems incredible that a species as
numerous as Markham’s Petrel could possibly have its principal breeding center
740 OCEANIC BIRDS OF SOUTH AMERICA
in such an insignificantly small bit of territory. Nevertheless, certain other
petrels are known to have an existence which hangs by a similar slender thread,
and Hormigas de Afuera deserves an early investigation of its bird life during
the months of June and July. It is, of course, possible that Markham’s Petrel
nests on no islands whatsoever, but rather in remote and inaccessible parts of
the maritime cordillera, as Hornby’s Petrel is believed to do.
Due to a hasty and unfortunate identification of which I was guilty, Chap-
man (1926, 183) has recorded three examples of this species from the coast of
Ecuador. On subsequent examination of the material, I learned that the
specimens are in reality examples of Loomelania melania, a migrant from the
North Pacific. Markham’'s Petrel, however, must also pass the Ecuadorian
coast, for Loomis (1918, 174) has recorded the species in latitude 13° 28’ N.,
longitude 108° 52’ W. (northwest of Clipperton Island) on August 1, 1905, and
just south of Cocos Island a month later.
The American Museum Collection contains about fifty specimens of Mark-
ham’s Petrel taken during the Brewster-Sanford Expedition, including a number
from approximately the type locality, off Tarapaca. We also have two males
collected by Mr. Charles L. Fagan in latitude 25° S. (north of Taltal), on Oc-
tober 15, 1925. Beck’s southernmost record is represented by a bird taken on
the voyage between Valparaiso and Juan Fernandez, during early December,
1913, at a distance of more than 150 kilometers from the Chilean coast. Paessler
(1913, 49; 1914, 277) and Wetmore (1923, 170) have reported on this petrel from
various points off the southern Peruvian and northern Chilean coasts. I found
it common between Mollendo and Pacasmayo during the first half of January,
1925, and later saw others off Point Parifias and Talara. When, however, the
countercurrent, El] Nifio, began to flow southward, stopping upwelling and
raising the temperature of the coastal water, Markham’s Petrels seemed to be
replaced in this region by the Black Petrels (Loomelania). On other occasions
I have seen Markham’s Petrels close to Macabi Island, and in a flock off the
southern point of Lobos de Tierra, but it is unlikely that either of these islands
is a breeding station of the species.
Beck’s notes report Markham’s Petrels in company with Hornby’s, and also
with Oceanites oceanicus, Oceanites gracilis, and Oceanodroma tethys. He found the
style of flight of each of these birds to be fairly distinctive, that of markhami
being described as slow beats, with frequent lifts to a meter or more above the
water, and then a sail. Both species of Oceanites, in contradistinction, flew with
more rapid beats, followed by a shorter sail.
Peters (1931, 73) and certain other recent writers treat Markham’s Petrel
as conspecific with Oceanodroma tristrami. I believe, however, that there are no
adequate grounds for regarding these two birds as other than thoroughly dis-
tinct species. Oceanodroma markhami has also been confused occasionally with
Loomelania melania, an error I myself have made, as noted above. The latter
two species are of approximately the same size, but the different lengths of their
respective tarsi show that they are far apart in structure and relationship.
In the British Museum I have examined the type specimen of Oceanodroma
MARKHAM’'S STORM PETREL 741
markhami. It bears no sex mark, but the describer states that it was a female.
The data on the label agree with the original description. Godman (1907, 27),
through a slip of the pen, reports an erroneous position which would locate the
terra typica in the heart of the Peruvian Andes. The coast off which the type
was actually taken should be called Chile, although it was Peruvian territory
at the date of the original description.
HORNBY’S PETREL
Oceanodroma hornbyi
Thalassidroma Hornbyi G. R. Gray, 1854, Proc. Zodl. Soc. London for 1853, p. 62 (‘northwest coast of
America’’ = west coast of South America).
Names: A synonym of the specific name is collaris.
Characters: A highly distinctive, gray-backed, white-breasted storm petrel, with a pronounced
collar across the breast, a dark cap, and a deeply forked tail.
Adults (sexes alike): Crown, nape, and circumorbital region dark neutral gray, forming a
pronounced cap; back and interscapular region neutral gray, continuous with a slightly more
brownish band encircling the breast and becoming mouse-gray or somewhat darker toward the
mid-line; a whitish transverse stripe on the upper back, just caudad to the nape, is produced in
certain specimens by wear of the feathers; back and proximal wing coverts close to fuscous, the
median and distal coverts hair brown or ashy brown, these as well as the outer edges of the secon-
daries and scapulars fringed with whitish; rump like back, blending into grayish upper tail coverts,
which are basally and laterally whitish; wing quills dark blackish brown, those of the deeply
forked tail somewhat grayer but without white except at the extreme bases of the feathers; fore-
head, lores, throat, sides of neck, and entire ventral surface, including the under tail coverts,
white, with a few obscurely grayish feathers on the flanks; axillaries and wing-lining gray, in
some instances with whitish borders to the feathers. Iris brown; bill and feet black.
The following table of measurements is based upon the type specimen, 19 others collected off
central Peru during June, and 2 from Ecuadorian waters collected, respectively, in September and
January.
Wing Tail Culmen Tarsus pane ve
Hsien Perera eee Tooter VF, FET aS 161.8 82.4 18.8 26 25.3 mm.
TD Ue MCeReS Py, MEET AA WEA, OE, 161 90 18.6 251. 25.1
Mexcwbypewrae) are beh bs nim halo. 168 96 17 26 23.5
Minimum of the series. ....... 157 76 17 24.5 23.5
Maximum of theseries ....... 169 96 19.2 275 27
The average lengths of wing and tail in this series may be somewhat less than normal, for
most of the Peruvian specimens are in exceedingly worn plumage, with replacement of the quills
just beginning.
Young Hornby’s Petrels are known only from one or more natural mummies found in Chilean
nitrate pampas, and the down has not been described. The egg is still unknown.
Distribution: Breeds presumably in the coastal desert mountains of Chile, and occurs along
the west coast of South America, mainly to westward of the coolest upwelling water in the Hum-
boldt Current. Recorded from between laritude 1° S., off Ecuador, and 32° S., off Chile, and to a
distance of 300 kilometers or thereabouts offshore from the coast of Peru. Northern-hemisphere
records are probably erroneous.
In 1922 I published an account of the fifty specimens of the hitherto little-
known Hornby’s Petrel which had been taken by Beck during June, 1913, off
742 OCEANIC BIRDS OF SOUTH AMERICA
the coast of Peru, between the latitudes of Ancén (11° 47’ S.) and Cerro Azul
(13° 4’ S.), but mostly far from shore (Murphy, 1922, 60). In the same paper
I referred to Philippi’s probable record of the nesting of the species in the
mountains to eastward of Taltal, Chile, and also to Paessler’s capture or identi-
fication of examples along many parts of the South American coast between
Islay, Peru, and Coquimbo, Chile.
Since the date of the paper referred to, I have observed Hornby’s Petrel 30
kilometers west of Point Parifias, Peru, on January 21, 1925; Wetmore (1923,
170) has published notes about examples taken near the Lobos Islands, Peru, dur-
ing July, September, and November; and Chapman (1926, 183) has recorded a
specimen collected off the Gulf of Guayaquil, on January 16, 1925, and another
which flew on board his steamer in latitude 1° S., off the Ecuadorian coast, on
September 13, 1922. The last-named bird was a female with reduced ovaries.
Chapman writes that on the date of its capture many petrels of the species were
noted along the steamship lane between the southern side of the Gulf of Guaya-
quil and the equator. The southernmost records for the species still seem to be
those of Paessler (1913, 43), who knew this unmistakable bird very well, and
who observed a few only a short distance to northward of Valparaiso in mid-
July, and of Beck, who saw two together about halfway between Valparaiso
and Juan Fernandez early in December, 1913. A bird representing a more
southerly station than any of the Brewster-Sanford specimens is one I have
examined in the Field Museum of Natural History, which was captured off the
international border between Peru and Chile on July 30, 1924.
From all of these data it would appear that there is little or no indication
of seasonal movement. Hornby’s Petrel seems likely to occur at any period of
the year in any part of its range which, so far as known, is roughly the
Humboldt Current zone between Valparaiso and the neighborhood of the
equator.
Mr. Beck first became acquainted with Hornby’s Petrel in the waters about
Hormigas de Afuera Islets, on June 4, 1913, a fact which emphasizes once more
the desirability of investigating these bare rocks, of which our ornithological
knowledge still amounts to almost nothing. Unlike Markham’s Petrels, how-
ever, the Hornby’s Petrels taken in this vicinity were evidently not about to
breed, for the notes on all the labels describe the gonads as small. Throughout
the remainder of this month of June, which proved so eventful in the discovery
of new or little-known sea birds, Beck constantly encountered Hornby’s Petrels
in company with many other small species but always well offshore, to wit, at
distances between about 40 and 300 kilometers from the continent. Most of
the specimens collected had recently completed moult and renewal of the
flight feathers, though some of them were still midway in the process. Not
a single example yielded any information as to the probable date of the breed-
ing season.
Beck’s notes describe the flight of Hornby’s Petrel as typically Oceanodroma-
like, a few rather slow strokes being followed by a period of scaling. Chapman,
however, who observed the birds flying in a stiff breeze south of San Gallan
HORNY “S) PET REL 743
Island, on June 23, 1916, writes that this species is ‘the most erratic flier I have
everseen . . . likea bat, swift, and nighthawk in one. They were skimming
here, flitting there, then suddenly swung off with the wind a hundred yards or
more so quickly one nearly lost sight of them’’ (Murphy, 1922, 62). An item
in Beck’s notes states that they were particularly conspicuous during hours
while the sun was still low, because their white breasts shone like silver as the
birds darted back and forth among the various species of black or black-and-
white petrels. The only example which I have ever watched at close range was
feeding while working up the wind, and it seemed almost to be creeping along
the surface of the water as it rounded the bow of my launch at a distance of
only a few paces.
Since the date of my earlier publication, Stresemann (1924, 61) has added
certain information of great interest regarding the probable breeding habits of
this species. He has received at the Berlin Museum a petrel mummy of recent
age, which he believes to be an example of Oceanodroma hornbyi. It was found
in December, 1923, as a result of the blasting of a saltpeter pit near Santa Luisa,
Chile, a locality on the nitrate pampa about 50 kilometers from the coast and
1600 meters above the level of the sea. The mummy is in excellent condition,
with the skin and horn still clinging to the legs and beak, with much of the
plumage, including the shafts of the wing and tail quills, well preserved, and
the skeleton entirely undamaged. Stresemann refers to Philippi’s earlier records
of two examples from the same general region, one of which was a chick still
covered with down.
Wherever Hornby’s Petrels nest, it seems almost certain that they must con-
gregate in very large numbers during the appropriate season, or else that their
breeding area is extraordinarily large. The discovery of the nesting grounds,
and the ultimate working out of the life history offers, therefore, a problem of
extraordinary fascination.
The stomach of a Hornby’s Petrel collected off the coast of Ecuador was
filled with small fish (Chapman, 1926, 183).
BLACK PETREL
Loomelania melania
Procellaria melania Bonaparte, 1854, Compt. Rend. Acad. Sci. Paris, 38, p. 622 (coast of California).
Names: A synonym of the specific name is townsendi.
Characters: Largest of the wholly black storm petrels of the west coast of America. A long-
legged, Oceanodroma-like species, with a deeply forked tail, the distance between the tips of the
shortest and longest rectrices amounting to as much as the length of the tarsus (approximately
32 mm.). :
Adults (sexes alike): General color sooty black on the dorsal surface, warm blackish brown
ventrally; scapulars and median and lesser wing coverts paler brown externally, with an almost
whitish edge, a condition enhanced by rapid fading and disintegration of these borders; quills
of wing and tail, and primary coverts, black, always with a rich fuscous or almost reddish tone;
head, neck, and mantle with a slight plumbeous gloss in fresh plumage only; wing-lining like
belly, an almost rusty brown which contrasts with the blackish brown border of the wing. Iris
brown; bill and feet black.
744 OCEANIC BIRDS OF SOUTH AMERICA
The measurements of a series from near California breeding grounds, in comparison with those
of a series from the tropical Pacific between Panama and northern Peru, are as follows:
Wing Tail Culmen Tarsus Middle toe
and claw
50”, San Benito and Coronados Islands,
aAnGlof Monterey, vey ech emeee 171 82.6 15.9 32 28.3 mm.
592, Coronados Is.; San José del Cabo,
ER Cee eee Oe eee wee ee ees, 173 82.6 16 32.6 28.8
Minimum of the seriesof 10 .... . 168 80 15 31 27
Maximum of the seriesof10.... . 177 86 16.5 34 30
o', Ecuador (lat. 1°S.), Sept.13 . . . 170 87 16 33.2 28.5
o?, Ecuador (lat. 1°S:), Sept.13. . . 168 84 15.5 33 275)
Sex?, Ecuador (lat. 1°S.), Sept.13. . . 174 86 16 33 29
&, W. of Pacasmayo, Peru (lat. 7° 30’
Solana edd ea 168 B 15 33 28
o', Balboa, G. Z., March 24... . . 161 78 17 32 28.5
i Balboa \GazaNanchn 24ers ee 157 87 16 32 29
Both Panama specimens were moulting the quills, which accounts for the short wing, etc.
Chicks are covered with long, soft down of a uniform fuscous color, darker basally. The
mesoptyle is darker than the protoptyle down.
The eggs are described as smooth and lustreless, white, usually unspotted, but sometimes with
a faint suggestion of lavender or reddish speckles about the larger end. Measurements of 61 average
36.6 x 26.7 mm., examples exhibiting the four extremes being 38.5 x 25, 36.5 x 27.5 and 32.5
x 24.2 mm. (Bent, 1922, 157).
Distribution: Breeds at islands off Lower California (San Benito and Los Coronados), and
migrates southward along the western coast of America at least to latitude 8° S., off northern
Peru. (Erroneously recorded from Japanese waters.)
The Black Petrel is a very distinct bird from its nearest relatives. Although
sharing many characters of the genus Oceanodroma, and having the same peculiar
“leaping” style of flight, it is, nevertheless, a remarkably long-legged petrel.
In the latter respect it constitutes a sort of nexus between the two groups of
Mother Carey's chickens which were formerly divided into two families known,
respectively, as the ‘‘Hydrobatidae”’ and the ‘‘Oceanitidae,’’ or into subfamilies
representing similar aggregations. Because of the peculiar morphology of the
Black Petrel, particularly as shown in the length of its tarsometatarsus, I
accept the generic name Loomelania recently proposed by Mathews (1934, 119),
regretting, at the same time, the obscureness and bastard derivation of the word.
Mathews'’s characterization of the genus is as follows:
Tarsus longer than the middle toe and claw, and almost twice as long as the culmen; the tail
is forked for over 20 mm., and is just less than half the length of the wing.
The axial skeletons and the bones of the wing show remarkably similar
proportions among all the storm petrels. The bones of the legs, on the con-
trary, illustrate a wide range of diversity. The least variable element is the
proximal one, as represented by the length of the femur. Among typical species
of the genus Oceanodroma, the tarsometatarsus approximates a length of one
and one-half times that of the femur. In Oceanites, a long-legged storm petrel,
the tarsometatarsus is more than two and one-quarter times as long as the
BERGK PE DRE 745
femur. Loomelania represents an intermediate condition. The following table
shows the relations among three elements of the leg in five species, the cnemial
crest being included in the length of the tibia. In each instance the length of
the femur represents unity. Femur Tarsometatarsus Tibia
Oceanodroma leucorhoa ........ (16.3 mm.) 1 1.48 2.31
Oceanodroma hornhyi. . . . 2... (15.35 mm.) 1 1.56 2.34
Oceanodroma macrodactyla ...... (18.2 mm.) 1 1.30 2.26
Loomelania melania ......... (17.45 mm.) 1 1.85 2.59
Oceanites oceanicus «ww wy we ee (14.65 mm.) 1 2353 3.42
Bonaparte’s type of the Black Petrel, which is now in the Paris Museum,
probably came from the vicinity of Los Coronados Islands, Lower California,
which are still an important breeding station. Our knowledge of the winter
range of the species has been extended successively southward to Guerrero and
Panama, and recent expeditions of the American Museum of Natural History
prove that the bird's migration carries it into the South Pacific, at least as far
as the central Peruvian coast.
As noted in my account of Oceanodroma markhami, a misidentification, for
which I was responsible, led Chapman (1926, 182) to record as that species
three petrels from Ecuador which are in reality examples of Loomelania. Wet-
more (1923, 170) has reported on two specimens taken near the Lobos Islands,
Peru, on September 22 and November 24, respectively. Through a lapsus calami
he speaks of the localities as “‘southern Peru,’ although they both lie close to
latitude 7° S. In the same waters I saw very many Black Petrels on September 7,
1919, and between January 4 and 15, 1920. In the course of my field work along
the coast of Peru during the latter period, I found the Black Petrels to be abun-
dant along the warm-water side of lines correlated with abrupt changes of
temperature in the northern part of the Humboldt Current region. During
January and February of 1920, for example, Oceanodroma markhami was one of
the common sea birds in the cooler upwelling waters close to the coast of the
continent, while farther offshore it was replaced by Loomelania melania; to
northward of Salaverry, in February, melania seemed to supplant markhami
altogether and, coincidentally, the unwonted warmth of the water showed
that an advance of the countercurrent had more or less changed the temperature
of the littoral everywhere off northern Peru. The Black Petrels were likewise
abundant from this region all the way to Panama. During a still more notable
advance of the countercurrent, in March, 1925, I found Black Petrels feeding
in the rain very close to desert shores that had begun to turn green, between
Zorritos, Peru, and the Gulf of Guayaquil.
Hallinan (1924, 306) observed and collected examples close to the Pacific
entrance of the Panama Canal, on March 24, 1915, a locality where I also ob-
served the birds on December 4, 1924. Chapman found them abundant off the
Gulf of Guayaquil in mid-September, subsequently capturing an example that
came aboard his steamship in latitude 1° S., off the coast of Ecuador.
Under the name of this species, Kuroda (1922, 310) has tentatively described
746 OCEANIC BIRDS OF SOUTH AMERICA
a new race, Oceanodroma melania matsudariae, from Japanese waters. Comparison
of this author's measurements with those of American birds shows, however,
that he was not dealing with any form of melania but rather with a petrel
characterized by a long wing, long tail, and very short tarsus. The recorded
measurements approximate those of Oceanodroma tristrami. For example,
Kuroda’s figures for the length of the tarsus range between 26 and 28 millimeters.
Those for specimens of melania are from 31 to 34 millimeters, despite the fact
that the wings and tails are much shorter than in the Japanese birds referred to.
It seems clear, therefore, that Loomelania melania is not yet known from localities
far from the west coast of the Americas.
The habits of the Black Petrel at its northern-hemisphere breeding grounds
are well described by Anthony (1898, 140; 1925, 287), Van Rossem (1915, 74),
Howell (1917, 32), and Loomis (1918, 175). At the north island of Los Corona-
dos group, off Lower California, this species has held its own, even though the
competition of auklets and of a white-footed mouse (Peromyscus) has driven out
some of the other nesting petrels. The Black Petrels breed in small scattered
colonies or in isolated pairs, and they apparently make no original burrows of
their own but use either the abandoned diggings of other birds or natural
crannies among the rocks. For such reasons, perhaps, they are better able to
stand the pressure of rivalry than are the burrowing and highly gregarious
petrels. In some cases the nests of the Black Petrels may be close together
among piles of slabs and boulders, but each pair seems quite as content to nest
in remote situations. The birds may excavate a little earth to enlarge the home
of which they have taken possession, but their only nests in actual burrows
seem to be those they have preémpted.
The nesting season is evidently prolonged, for eggs have been found betwee
early June and September. The mating of the birds is under way at Los Corona-
dos well before the end of April, and at this season the night air rings with
their calls, which sound like tuc-a-roo, tuc-tuc-a-roo. The egg is laid on bare soil,
without nesting material of any sort. Young have been noted as early as July 4,
but eggs are not uncommon even as late as August 13. When disturbed, the
Black Petrels act in the usual manner of their family, ejecting streams of orange-
colored oil, striking savagely, and even biting their own wings in their rage.
The principal food of the Black Petrel near its breeding grounds seems to be
composed of the larval free-swimming stages of spiny lobsters. Softer marine
organisms have been reported by Hallinan, and the birds have been obsetved to
dive well beneath the surface in search of their prey. Along the Peruvian coast
they appear to be interested in refuse from steamers. Their principal natural
enemies at the nesting grounds are falcons, and introduced creatures such as cats,
rats, and mice.
GRAY-BACKED STORM PETREL
Garrodia nereis
Thalassidroma Nereis Gould, 1841, Proc. Zoél. Soc. London for 1840, p. 178 (Bass Strait, Australia).
Names: In common with other small petrels, this species is in some places called Night- -bird
and Fire-bird. Synonyms of the specific name include sa/ratrix and longipes.
GRAY-BACKED STORM PETREL 747
Characters: A small, square-tailed petrel resembling Oceanites, but lacking a white patch above
the tail and with an entirely white belly.
Adults (sexes alike): General dorsal color ashy gray, darkest on head and nape, where it is
somewhat sooty or brownish, and lightest on rump and upper tail coverts; feathers of mantle,
scapulars, and adjacent wing coverts narrowly margined with white in fresh plumage; remainder
of wing blackish, with a grayish or silvery gloss on the webs of the quills, and with narrow white
terminations to the secondaries and inner primaries; the dark hair-lines of the feather shafts are
more or less conspicuous over the entire dorsal surface, from mantle to tail; rectrices gray like the
rump, with a broad blackish terminal band, least conspicuous on the lateral feathers; head, neck,
and upper breast grayish black, slightly brownish on the forehead; remainder of ventral surface,
axillaries, and inner wing coverts white, except for a few mottlings of gray on the feathers of
the flanks and under tail coverts; marginal coverts of under-wing grayish black, like the outer
surface. Iris brown; bill and feet black.
10 specimens of both sexes from the Falkland Islands and New Zealand seas: wing, 123-135
(129.2); tail, 59-66 (62.7); exposed culmen, 11.7-14 (12.9); tarsus, 30-34.5 (31.9); middle toe and
claw, 24-28 (26.4) mm.
Young moult from Quaker drab mesoptyle down into plumage resembling that of the adult.
Eggs from the Falkland Islands are white with fine reddish dots which, as in so many other
petrels, are sometimes generally distributed and again confined mostly to a ring around the larger
end. Two examples measure 32 x 23.4 and 31.5 x 22.7 mm.
Distribution: Of sub-antarctic and low antarctic distribution, penetrating most deeply into
the Antarctic Zone at South Georgia. It nests also at the Falklands, Gough Island, and Kerguelen
Island in the southern Indian Ocean; also at Macquarie, Auckland, Bounty and the Chathams,
as well as at islets closer to New Zealand.
The American Museum Collection contains 12 specimens of this petrel, of
which 8 are from the Falkland Islands and neighboring waters, and 4 from the
New Zealand region. Other examples have been examined in the British and
Berlin Museums, besides which I have borrowed for comparison the series
belonging to the California Academy of Sciences, the United States National
Museum, and the Museum of Comparative Zodlogy.
The material studied does not bear out the differentiation of the species into
several subspecific forms. Four adults from the Falkland Islands, for example,
are indistinguishable in dimensions, pattern, and shade of coloration from four
from the New Zealand region. The latter, taken at sea during the Whitney
South Sea Expedition, have slightly more worn quills than the Falkland nesting
birds, but one of the New Zealand specimens has the longest wing measurement
in the whole series, although Mathews (1912, 18) has based a Falkland race
upon the reputed greater Jength of the wing. Eight skins from Kerguelen Island
also entirely agree with the others. The sexes in this species show no appre-
ciable discrepancy in size.
During the Brewster-Sanford Expedition, Beck encountered the Gray-backed
Storm Petrel for the first time in the Strait of Le Maire on May 9, 1915. In
September of the same year he saw many at sea around the Falkland Islands, and
found that they behaved like the Wilson’s Petrels in responding to the lure of
bait laid upon the water. His notes also speak of numbers of Gray-backed
Petrels hovering over rafts of floating kelp in a heavy sea and a gale.
Later, at Cochon and Kidney Islands of the Falklands, he found nests of the
species in hummocks of the tussock grass. There was no actual burrow, but
748 OCEANIC BIRDS OF SOUTH AMERICA
rather a space enlarged in the more or less dead plant tissue and vegetal mould
of the basal clump or pedestal of the plant. A small hole indicated where the
birds entered and departed from the hummock, and Beck located the nests by
running his hand into such openings and rummaging about among the dry
grass stalks. On November 5 and 6, at Cochon Island, he shook out the first
incubating bird, a female, and its fresh-laid egg. Its tussock hummock stood
in the midst of a colony of several thousand Rockhopper Penguins, and Falk-
land Diving Petrels were also occupying burrows round about. On November
19, at Kidney Island, he took a slightly incubated egg from a similar site,
except that in this instance the petrels’ nest was directly above the burrow of a
Magellanic Penguin. Four downy young petrels, just beginning to show their
contour plumage, were collected in the same neighborhood at Kidney Island
on January 13,1916. Their feathering, in so far as it shows, is indistinguishable
from that of adult birds.
Oliver (1930, 98) records the eggs of this species from New Zealand as con-
siderably larger than ours from the Falkland Islands, his figures running up to
37 x 27 millimeters. If this be correct, there is doubtless a considerable range
of variation in egg size, for I have already shown that birds from the New Zea-
land region are not different in size from those taken at the Falklands.
At South Georgia the Gray-backed Petrels also nest among the hummocks
of tussock grass (Poa flabellata), as reported by Pagenstecher (1885, 18), Lénn-
berg (1906, 84), and von den Steinen (1890, 242). The last-named, however,
found one bird of this species in a rock crevice on the south slope of Mt.
Krokisius, at Royal Bay. Nesting evidently begins at South Georgia during
early November, and the adults and grown young, according to Pagenstecher,
leave the vicinity of the island about the end of April.
The right of this species to a place in the avifauna of Gough Island is based
upon a specimen shot by firelight, while it was flying over the beach, about
June 1, 1922 (Wilkins, 1923, 508). It is, of course, barely possible that this
example was merely a pelagic bird that had been attracted ashore by the blaze.
At Kerguelen Island, according to Kidder (1875, 31), the Gray-backed Petrels
were found in their burrows on October 28, and the first eggs were discovered
on December 12. Eaton, as quoted by Sharpe (1879, 129), describes the night
singing of one of these petrels, a custom doubtless associated with courtship.
On November 6 he was aroused from sleep by the faint cry of a strange bird.
Going out to search with a Jantern, he discovered a Gray-backed Petrel, which
proved to bea female, sitting on the open ground and uttering a crake-like call.
It made no effort to escape, and was picked up by hand.
WILSON’S PETREL
Oceanites oceanicus oceanicus
Procellaria oceanica Kuhl, 1820, Beitr. Vergl. Anat., Abth. 1, p. 136, pl. 10, fig. 1 (no type locality given;
South Georgia designated by Murphy).
Names: Mother Carey's Chicken; ‘‘Pampero”’ or ‘'Petrel de Tormenta”’ in Spanish-speaking South
America, and ‘‘Alma de Mestre’’ in Brazil. The principal synonym of the specific name is wi/sont.
WILSON'’S PETREL 749
Characters: A square-tailed, black storm petrel, conspicuously white above the tail, and with
long legs which bring the extended feet beyond the end of the tail.
Adults (sexes alike): General color blackish brown, slightly paler on the throat and belly
and darkest on the wings and tail; a leaden or grayish gloss on the dorsal surface is not conspicuous,
and is present only in fresh plumage; median and greater wing coverts lighter than remainder of
wing, being of an ashy brown, outwardly fringed with whitish in fresh plumage, and forming a
pronounced band on the wing; inner secondaries likewise ashy brown and thus lighter than re-
mainder of quills; upper tail coverts white, a few of the black rump feathers adjacent to them white-
tipped, the whole forming a broad, roughly quadrangular band across the base of the tail; lateral
rectrices basally white in a narrow strip on the inner web adjacent to the shaft, which is likewise
proximally white for about half its length; large white patches on the lower flanks and thighs,
together with more or less intermingling of white feathers in the lateral lower tail coverts, the
whole forming a continuous area with the white above the tail; lining of wings substantially
like the breast. Iris dark brown; legs and feet black, the webs largely orange-yellow for about
three-fourths of their length from the base.
Whitish feathers in the lores, and narrow whitish borders on the feathers of the belly, are
included in a descripticn of adults by Witherby (1924, 417). So far as I can judge, however, both
of these marks appear to be confined to juvenal plumage.
Measurements based upon nearly 100 specimens collected in many parts of the North and South
Atlantic, including breeding grounds at South Georgia, are as follows (Murphy, 1918, 127):
Mi
Wing Tail Culmen Tarsus eek
O7cand 1O- Atlanbice st. ears ca isho 144.9 63.7 12.6 34.6 27.5 mm.
Minimum of the series. ....... 136 56.5 lasik 31.3 25.3
Maximum of theseries ....... 155.5 73 15.2 36.8 30
Fifteen additional skins in the American Museum Collection were obtained by Mr. Beck along
the coast of Patagonia, and in the region between the eastern entrance of the Strait of Magellan
and the Falkland Islands, during May, September, and October, 1915. These include specimens
in juvenal plumage as well as adults, their average dimensions being:
Mi
Wing Tail Culmen Tarsus es
ra tal 0° Fe RA ES Pee mee 139.7 61 11.8 34.4 27.2 mm
In Beck's material are also 10 typical examples taken off Mar del Plata, Argentina, between
September 28 and October 21, 1914. Most of these had swelling gonads, and were doubtless south-
ward bound toward nesting areas.
Finally, the Museum has received from Mr. A. G. Bennett, of Port Stanley, Falkland Islands,
a series of breeding adults collected at Deception Island, South Shetlands, between December,
1921, and March, 1922. The measurements of these are as follows:
|Middle toe
Wing Tail Culmen | Tarsus ip Le
Sony! Sat fae ay Lae, € 148.2 66.9 12.9 34.3 | 28.1 mm.
Bae sts SWE etd Us, Se HR 151.3 68.3 | 12.9 35.1 | 29.2
Minimum of theseries. ...... . 144 62.5 12.1 33.6 26
Maximum of the series ....... 158 73 | 13.8 36.5 Shy)
The figures compare well with those of 12 breeding birds from South Georgia recorded by
Murphy (1918, 125).
750 OCEANIC BIRDS OF SOUTH AMERICA
Wing-spreads of 6 specimens collected in the tropical Atlantic during October, or shortly after
the completion of the moult, ranged between 383 and 412 mm.
Valette (1906, 61) gives the length in the flesh of a breeding example at the South Orkneys
as 170 mm.
The nestling down is uniform grayish black. Unlike most petrels, this species has a distinctive
juvenal plumage, the marks of which comprise white edgings on the feathers of the belly and a
whitish spot in the lores. These marks are lost through wear of the terminations of the feathers,
and it is probable that no post-juvenal moult occurs until the petrels are about one year old.
The egg is an elongate oval of dull white, peppered chiefly around the larger end with tiny dots
of reddish brown. Measurements of 15 average 32.2 x 23.2 mm.; the eggs showing the four ex-
tremes measure 33.5 x 23.5, 33 x 24, 28 x 23 and 32.5 x 22.5 mm. (Bent, 1922, 168). It is possible
that some of the eggs included in the above summary pertain to the slightly smaller Fuegian race,
discussed in the next biography. Eight eggs from the South Orkneys, which undoubtedly rep-
resent the typical subspecies, average 33.7 x 24 mm.; the largest is 36 x 24 and the smallest
32 x 23 mm. (Clarke, 1913, 235). Bennett (1927, 79) records the average of a series of South Shet-
land eggs as 32.9 x 23.6 mm.
Distribution: Breeds at South Georgia, the South Orkneys, South Shetlands, and islands of
the Antarctic Archipelago, probably southward to the shores of the continent; migrates north-
ward to the northern North Atlantic; the species nests also at other islands in the circumpolar
antarctic ring, including Kerguelen in the southern Indian Ocean and Heard Island (Moseley,
1879, 230), but the subspecific status and winter range of Old-World Wilson's Petrels have not
been satisfactorily determined.
In an earlier paper I have reported at some length upon the Wilson's Petrels
collected by myself at South Georgia, as well as those obtained during the course
of Beck’s South American field work. We are justified in believing that birds
from all parts of the North and South Atlantic represent a single subspecies,
which migrates from breeding grounds at islands of the Scotia Arc, and perhaps
also from Bouvet Island and other antarctic localities still very imperfectly
known. Migrants in the eastern part of the Pacific, however, seem to represent
a smaller race, the sub-antarctic breeding grounds of which were discovered
during the Brewster-Sanford Expedition. These will be considered in the next
biography.
Along the east coast of South America, Wilson's Petrel is a familiar and
often abundant sea bird from the Caribbean southward. Beck observed north-
bound migrants near Dominica and other islands of the Lesser Antilles, and
south of Porto Rico, during April and May, 1917, and Beebe (1909, 74) reports
one blown by a storm into an estuary of the Orinoco on March 25. Between
April 15 and May 1, 1916, Beck collected many young birds off Bahia, Brazil.
By these latter dates the vanguard of the spring migrants has already reached
temperate North Atlantic latitudes. It may well be that birds of the year make
less extensive migrations than their older fellows. At any rate, specimens
determinable as in juvenal plumage are rare in collections of North Atlantic
birds, although very common in those from the tropics. The Wilson's Petrels
observed by Beck along the Brazilian coast were also notably given to the
practice of resting on the water in groups, a custom apparently not character-
istic of adult birds. The species has been commonly reported in the harbor of
Rio de Janeiro (Goeldi, 1894, 588), at Sio Paulo (von Ihering, 1907, 36), and
WILSON’S PETREL 751
southward to the Atlantic coast of Patagonia, where Beck collected examples
during May, September, and October of 1915.
Most of the specimens taken along the tropical coasts of South America and
Africa, during the months of northern-hemisphere spring, appear to be young
birds. The majority collected offshore in the same season and latitudes are, on
the other hand, fully adult. This suggests that the fledglings may follow the
coast lines of the southern continents during their first northward migration.
That the adults, on the other hand, do not preferably migrate along the con-
formation of land masses is known from abundant data. The naturalists of the
‘Scotia’ found the species in numbers in the vicinity of Gough Island in April,
1904, the season of northward migration. This locality lies about as far from
a continent as it is possible to go in the South Atlantic.
The whereabouts of the first-year birds during the northern winter, or breed-
ing season, is a matter of considerable uncertainty. The fact that the young
undergo no moult until after they have left the North Atlantic, and probably
not until their second summer, tends to confirm an inference drawn from exam-
ination of breeding birds from South Georgia, namely, that yearlings do not
breed. Perhaps, therefore, they spend their entire first year at sea, a supposition
which would explain the occurrence of Oceanites in the tropical Atlantic during
November and other winter months.
Wynne-Edwards (1935, 285) shows that the migration into the northern
hemisphere reaches its extreme bounds at about latitude 50° N. in the Atlantic.
The migrants head for the Gulf Stream, annually reaching Cape Hatteras about
April 18, and making an almost simultaneous invasion into the mild waters
along the entire Atlantic coast of the United States. During May and June
they gradually work inshore. They are rare in the Sargasso Sea, as known from
Jespersen’s observations, but thick in Gulf Stream waters. In the eastern
Atlantic they do not appear at all until well into May. Wynne-Edwards writes:
All three of the southern Procellariidae which regularly visit the North Atlantic, namely the
Greater Shearwater, Sooty Shearwater and Wilson's Petrel, agree in appearing first in North
American and lingering last in Africo-European waters. This is scarcely likely to be a co-
incidence.
Throughout a round trip between New York and South Georgia, I saw
Wilson's Petrels on all but a few days, as shown in a tabular record already
published (Murphy, 1918, 133). I observed the birds under many conditions
of wind and weather, and in company with a large number of other species.
I found that the simplest and most reliable way to distinguish Wilson's Petrels
from other Mother Carey's chickens was by their peculiar style of flight, which
consists of an alternate gliding and fluttering, producing a forward movement
of very different appearance from the “‘leaping’’ strokes of Leach’s Petrel or
other members of the genus Oceanodroma. I learned, too, by feeding these birds
with bits of fat from the stern of my brig, that they can dive very skilfully to
a depth of several times their length, almost invariably recovering sinking bits
of food and then leaping forth dry into the air. Schools of feeding surface fish,
such as carangids, cause the Wilson's Petrels to gather rapidly and to skip along
152 OCEANIC BIRDS OF SOUTH AMERICA
in search of scraps from the slaughter. After following a vessel all day long, the
travellers sometimes become doubly active toward sunset when, ceasing for a
time to hunt for food, they dash hither and thither, sometimes shooting up-
ward almost as high as the masthead and then plunging down at high speed.
Such behavior, which I observed only on the southward voyage during October,
may have been prophetic of courtship, although it is hardly likely that mating
takes place until after the selection of territory at the breeding grounds.
Like all small dark petrels, this species is difficult to see against water ruffled
by the wind, and only rarely does it rise above the horizon of a person standing
on the deck of a ship. The birds therefore often rush into the field of vision and
appear at close range after the observer has been vainly scanning the water in
the distance. During calms, when the ocean is silvery, they are silhouetted
against it and are visible from afar. When following a vessel, they skip along
the surface as they approach, giving a vigorous kick on the lee side with both
feet whenever they touch the water. When they ‘‘stand"’ to feed, the wings
are held rigidly and they face the wind; the momentum necessary to keep them
from being blown away is furnished by the webs, the legs sinking to the heel
as they work backward in unison. Why their almost weightless bodies are not
whisked off to leeward like fluffs of down is a good deal of a mystery. Regard-
less of the strength of the gale, however, they contrive to move forward in the
apparently effortless, dreamlike manner that seems to defy both wind and
gravitation.
Although Wilson's Petrel is to be found north of the equator well into the
month of October, the returning migrants reach their West Antarctic breeding
grounds early in November. At Paulet Island the species was first observed by
Andersson (1908, 47) on November 8. At the South Orkney Islands the first
arrivals have been seen on November 11 and 12 of successive years, the great
bulk of the population coming not more than ten days Jater, after the breaking
up of the sea-ice. Here the first egg was found on December 11 (Clarke,
1913, 234).
During January, 1909, members of the French Expedition discovered 20 nests
among the rocks at the southern end of Petermann Island. They were situated
mostly under great stones, or in deep crevices sheltered from the sifting snow.
The first eggs were found early in January. The last birds of the species were
observed about this locality on April 20, and the first arrival of the next autumn
returned on November 23 (Gain, 1914, 124). Bennett found eggs at the South
Shetlands on December 26. Racovitza (1900, 195) records the species nesting
southward as far as De Gerlache Strait.
The type of nest depends in part upon the nature of available material. At
the South Orkneys eggs have been found in completely unlined cavities. At
Kerguelen Island the nests are built of plant stalks, while in the Ross Sea region
and in West Antarctica they have been found to be made of a comfortable
collection of penguin feathers.
At South Georgia this petrel appears, according to Matthews (1929, 577),
in November and remains until May, congregating about the whaling stations
WILSON’S PETREL 753
in particularly large num)ers during February and March, so that the water of
the fiords sometimes beccmes black with them. Matthews continues:
It lays its egg in crevices of the cliffs and amongst the stones of screes. No nest is made but the
same burrow is returned to year after year, so that a quantity of debris—feathers, dead young and
so on—is accumulated on which the egg is laid. The eggs are difficult to obtain, as those in the
cliffs are usually inaccessible, and among the screes they are so far in that it is often impossible to
remove enough stones without causing a land slide. The sitting bird makes a low whistling cry
which is very difficult to locate. At dusk the birds flit about near the entrance to the nesting hole
and produce a harsh grating noise. The eggs are laid in early December and both sexes take part
in incubation. When captured the birds squirt from the mouth and nostrils a dark red oil with
an evil odour. They are unable to stand with the tarsi erect and shuffle in and out of the burrows
with the whole length of them on the ground.
The above account agrees substantially with Clarke’s description of the
nesting habits at the South Orkneys. At the latter islands, unusually cold
summers apparently cause very high mortality, and it is probable that during
certain years only a small proportion of the eggs hatch. The period of incuba-
tion is not shorter than 35 days.
When I reached South Georgia on November 23, 1912, Wilson's Petrel was
already common in the fiords and enormously abundant on the whaling banks
offshore. On December 1, just at dusk, great flocks were seen feeding in King
Edward Cove, Cumberland Bay. I failed, in spite of patient search, to discover
a nest, but many of the birds I shot were undoubtedly incubating.
At the Bay of Isles, near the northwestern end of South Georgia, the crew of the ‘Daisy’ en-
gaged extensively in sea elephant hunting, with the result that quantities of blubber lay soaking
in the water alongside the vessel much of the time. This attracted flocks of Oceanites, especially
during gales, when groups estimated to comprise as many as six hundred birds often foraged for
globules of oil washed out of the soaking blubber.
Over the headlands and tussock flats along the Bay of Isles, the birds were frequently seen
flying back and forth like martins, but I never spied one in the act of alighting at its nesting site.
On the morning of Feb. 1, I watched a single bird for a quarter of an hour while it dashed to and
fro and up and down before a steep, rocky bank near the bay. It flew precisely as though it were
hawking winged insects, which was, of course, very unlikely. For several minutes it was chased
in all its gyrations by a pipit (Anthus antarcticus), the latter trying vainly to keep close behind it.
Finally it flew off without disclosing the nesting site, if indeed it were in the neighborhood.
A most interesting point about Oceanites at South Georgia is a fact of an ecologic nature,
namely, that this species, practically alone among the smaller water birds, enjoys absolute im-
munity from the aggressiveness of the skua (Catharacta). Lonnberg has recorded this before but
my observations of the actual conditions were none the less a source of considerable surprise to me.
The skua is to most of the birds, large or small, a wanton and relentless ogre. It is forever watching
for neglected young of penguins, cormorants, and even albatrosses; it attacks at sight the endemic
teal, the diving petrel, and the Prion. To the last two species, it is such a terrible foe that they
dare not show themselves in the fiords or over the land between daylight and dark; nevertheless,
the skuas succeed in capturing so many of them that their dismembered carcasses strew the ground
over their subterranean colonies. But Oceanites flies about with impunity in broad daylight. I
have seen one almost brush a skua with its wing as the latter bird stood ona rock in the kelp fields,
and both species sometimes fed together when stormy weather had washed away pieces of seal
blubber from the supply floating alongside our brig.
Why does the skua ignore this petrel? It is surely as conspicuous as the diver (Pelecanoides)
and seemingly less difficult to capture than the fleet-winged Prion. The protective character cannot
be in an offensive taste, for the skua is quite ready to pounce upon and devour a dead or disabled
754 OCEANIC BIRDS OF SOUTH AMERICA
Oceanites. Possibly, however, its body affords too small a morsel to warrant any effort on the
skua’s part. It is noteworthy that the latter grants a like immunity to one other still smaller
bird, the pipit (Anthus).
Wilson's petrels were present in apparently undiminished numbers when we left South Georgia
on March 15, 1913. As the ‘Daisy’ stood to sea from Possession Bay, I had occasion to make a trip
in a whaleboat to a neighboring whaling station for the purpose of posting mail. Shortly after
sunset we started on a ten-mile pull to the brig offshore, and, as soon as we were well out from the
land, our boat was continually in the midst of innumerable small Tubinares flocking over the
quiet sea. Qceanites made up a considerable proportion of these birds, which fluttered all about
us. Their indistinct forms kept flashing above the skyline, but their myriad numbers were revealed
still more by a chorus of twittering and the soft unbroken sound of winnowing quills (Murphy,
1918, 142).
The voice of Wilson's Petrel at sea is expressed in soft peeping and rasping
notes. Their calls at the nesting ground, which are kept up all through the
hours of darkness, have been described as cooings, twitterings, low whistles,
harsh screaming chuckles, etc. At Kerguelen, according to Hall (1900, 19),
their croaking begins very actively about eight o'clock in the evening, when
the parent birds change shifts on the egg.
The food of Wilson's Petrel comprises a wide variety of marine organisms,
especially crustaceans of many orders. Examples shot in the antarctic pack-ice
are usually well filled with small euphausians. The place of small fishes or
squids as food is often indicated by otoliths and crystalline lenses in the stomachs
of the birds. They take also whatever food they can pick up from the destruc-
tive work of large fish or of whalemen. At South Georgia I saw them constantly
foraging about the carcasses of whales, and even snatching at tiny bits of
carrion shaken from the beaks of Giant Fulmars and other large species. Oil
or fat of any sort, spread upon the water, will quickly attract these petrels if
any are in the neighborhood, a fact of which Beck took full advantage during
his collecting off Mar del Plata, Bahia, and elsewhere. When following a ship,
Wilson's Petrels are interested in practically every kind of refuse from the galley.
FUEGIAN PETREL
Oceanites oceanicus chilensis, new subspecies
Subspecific Characters: Differs from Oceanites oceanicus oceanicus of the Atlantic Ocean in its
smaller size, especially in the length of wing and tail.
Type.—No. 3316, Brewster-Sanford Coll., Amer. Mus. Nat. Hist.; @ad., nesting; Wollaston
Island, Fuegia, Chile, Jan. 1, 1915; R. H. Beck.
Measurements of 11 birds collected on or near breeding grounds at Wollaston and Morton Is-
lands, Nassau Bay, and at Magallanes in the Strait of Magellan, between December 17, 1914, and
March 6, 1915, are as follows:
l ;
; 2 Middl
Wing Tail Culmen Tarsus oe ie
Sos Ma teal ele Teo Ries Maman Caekey 133.9 Sy /eF/ 11.6 34.6 27.5 mm.
5 Oi Me ee Sen ey! Oe ee 2 138.3 61.3 11 35.7 27.5
The tables below are based upon specimens collected off Corral, Chile, and at various points
west of Valparaiso, up to a distance of 250 kilometers from shore, between September 17, 1913,
FUEGTAN PETREL 135
and March 16, 1914; and upon others taken off Callao and Ancon, Peru, from the coast to about
75 kilometers offshore, between May 1 and June 16, 1913.
Middle toe
Wing Tail Culmen | Tarsus [iin claw
aU. troy Nt 4 ov (ig a ae ec OE 140.6 59.5 11.7 33.8 27 mm.
DOR MGCL cn pa ahs ois es ailisjue GS 143.6 61 10.5 33.5 25.8
SG SRCLO cis, fe feo rep nts ci) stays, 134 58 11.6 35.1 v7 joe
LO QePera ie anes te bee He, oes 136.2 59.2 11.6 35.6 27.1
Dimensions based upon the whole series of 51 measured specimens are as follows:
Middl
Wing Tail Culmen | Tarsus |. ea paid
Ban Oe ee Salah 137.2 59 WES 34.7 27 mm.
Minimum of theseries. ....... 130 55 10 33 24
Maximum of theseries ....... 146 63 12.5 36 29
Comparison of the summarized data in the last table with figures pertaining to the typical race
of oceanicus shows that chilensis is consistently smaller in the lengths of wing, tail, and culmen.
The fact that certain extreme measurements overlap does not invalidate the distinction.
The wing-spread of a female collected off the Chincha Islands, Peru, October 22, 1919, measured
353 mm.
Egg: An egg taken by Beck at Wollaston Island, Chile, just north of Cape Horn, on January 1,
1915, is dull white, with an indistinct wreath of very fine purplish red spots about the larger end;
it measures 31.9 x 22.9 mm. Eight others, from Deceit and Herschel Islands, are described by
Reynolds (1935, 95) as ‘‘thin-shelled, white, finely peppered with reddish-brown and underlying
pinkish-lilac, forming in the majority a zone about the larger end. Average of eight eggs 32.1
x 22.9 mm., max. 34.75 x 22, and 31 x 24 mm., min. 31 x 23 and 34.75 x 22 mm."
Distribution: Breeds on islands near Cape Horn, and ranges throughout the Magellanic water-
ways and northward along the western coast of South America at least to central Peru. Probably
resident also at the Falkland Islands.
The name Oceanites oceanicus chilensis was first published by Alexander (1928,
86), who gave no description but stated that the subspecies breeds on ‘‘islets
off Cape Horn."’ Both Peters (1931, 68) and Reynolds (1935, 94) have pointed
out that the name has hitherto been a momen nudum. In describing herewith
this small, sub-antarctic race of Wilson's Petrel, it behooves me to explain
the prior use of the trinomial.
During the preparation of Mr. W. B. Alexander's ‘“‘Birds of the Ocean,"’ this
author worked for several weeks in the American Museum of Natural History.
At that time I had prepared the description of this petrel in manuscript, and
had designated a type specimen by attaching the usual red label. In studying
and listing the storm petrels, Alexander naturally assumed that a valid diagnosis
of this race had been published, and therefore included it in his account.
More than sixty skins of this subspecies were collected by Beck in the Fuegian
region and along the coasts of Chile and Peru. Comparison with a thoroughly
adequate series of typical Wilson's Petrel shows that it is characterized by
markedly and consistently smaller size than the widespread Atlantic form. The
756 OCEANIC BIRDS OF SOUTH AMERICA
fact that the new race nests among the islands bordering Tierra del Fuego is of
particular interest because it brings a representative of the species oceanicus
within the Sub-Antarctic Zone of surface water as a nesting bird. In all other
parts of the New World the species is known to breed only in the Antarctic
Zone. Kerguelen Island of the Indian Ocean, however, lies practically on the
Antarctic Convergence, and furnishes a parallel to the zonal conditions obtain-
ing near Cape Horn. It would not now be surprising to find the Fuegian race
also nesting at the Falkland Islands where, in fact, Bennett (1926, 313) indicates
that its eggs have perhaps been found.
The lesser size of specimens of Oceanites oceanicus from the west coast of South
America has been noted before, for Giglioli once (1870, 36) resurrected Bona-
parte’s name wé/soni for smal] examples collected off Chile. Bonaparte’s de-
scription, however, referred to the Atlantic bird, and his name is preoccupied
by Kuhl’s Procellaria oceanica, for which reason wilson is not available for the
subspecies occurring in the eastern Pacific.
Mr. Beck encountered this petrel at its breeding ground near Cape Horn
during December, 1914. On New Year's Day, 1915, he collected a male bird,
which I have selected as the type, sitting on its egg in a crevice between large
boulders just above the shore line of Wollaston Island. He had every reason
to believe that the petrels were nesting also at Ildefonso and Hoste Islands.
On January 2, at Deceit Island, just northwest of Cape Horn, one of the birds
came in during the daytime while a strong gale was blowing, and entered a
hole under a great rock close to the water. This example, which likewise
proved to be a male, was drawn out with a stick, as was also a fresh-laid egg
that was later broken and lost. On subsequent dates Beck found these petrels
in breeding condition near Chanticler and Hall Islands. During the same
season he also saw and collected many in Nassau Bay, the Brecknock Pass, and
northward through the inland waters to the Strait of Magellan. Oustalet
(1891, 165) likewise records specimens taken in the Magellanic region between
October and March, one of them being obtained at Gable Island in Beagle
Channel.
A recent account of experiences with the Fuegian Petrels during December,
1932, is that of Reynolds, who writes:
Storm-Petrels were common in Nassau Bay, and a few were met with even near Ushuaia in
the Beagle Channel. At Freycinet and Herschel they came flying close along shore late in the
evening, and some were seen east of Deceit during the day. Near Cape Austin on Deceit I found a
breeding burrow with the entrance well hidden in a mound of Azorella partly covered by Empetrum.
There was some attempt at a nest of Empetrum twigs at a depth of about 3 feet, and on this a male
(the specimen collected) was brooding a nearly fresh egg . .
On Herschel the dog accidentally discovered a nest, and next day six eggs were found with his
aid. The burrows were in surprisingly wet situations, and were often natural holes where the
surface of peaty turf, with its covering of Empetrum and other plants, had become raised from sodden
clay by the roots of stunted shrubs of the evergreen beech. The nests were rather scattered on
comparatively low ground at little distance from the shore, and each contained a fresh egg.
To northward of the nesting area, Beck’s notes record numbers of Wilson's
Petrels, presumably of this race, in the Gulf of Pefias on July 4, 1914, and over
FUEGIAN PETREL 757
the ocean between Valparaiso and Juan Fernandez during November and Decem-
ber as well as in February and March. Still farther northward we have records
and specimens from many parts of the Chilean and Peruvian coasts, as far as
Callao, Ancén, and the Guafiape Islands.
The Peruvian specimens, taken during May and June, were undergoing
moult of the quills. November and December birds; from off Valparaiso, have
full-grown, unworn quills, and the longest average wing-length. March birds
from Fuegia are in freshest body plumage, with broadly white-edged secondary
coverts. Many of Beck's central Chilean specimens had enlarged gonads, and
the collector believed that some of those shot off Valparaiso may have been
nesting birds. Their claws, however, are all long and pointed, whereas those
of specimens taken on known breeding grounds among the Fuegian islands have
claws which have been worn more or less blunt, as if by burrowing.
This race exhibits all of the juvenal plumage characteristics which have
been described for the Atlantic bird. A young male collected north of Tal-
caguano, on March 1, 1925, for example, has conspicuous white loral or pre-
orbital spots, extensive white edgings on the feathers of the belly, and gray,
white-edged inner secondaries.
I collected additional specimens of this petrel in the Bay of Pisco, Peru, in
October, 1919, and observed the form farther northward during the midsummer
period, 7. ¢. the height of its breeding season. All examples taken here, however,
had small gonads.
On its northward migration this subspecies is primarily a bird of the cool
Humboldt Current. Whether or not it ever crosses the equatorial regions is
still to be determined, for Loomis (1918, 180) gives no description of the speci-
men of 0. oceanicus captured at Monterey, California, in August.
The stomachs of my Pisco Bay specimens contained cinders, bits of fish,
numerous nereid worms, and a few feathers. One of them also had two air-
vesicles of a seaweed, and another hundreds of small, uniform, chitin-covered
objects which appear to be the eggs of a mollusk.
ELLIOT’S STORM PETREL
Oceanites gractlis gracilis
Thalassidroma gracilis Elliot, 1859, Ibis, p. 391 (’‘west coast of America’’ = coast of Chile).
Names: In Chile and Peru this and other small storm petrels are known as ‘‘Bailarines’’ (ballet
dancers), or ‘‘Felices.”’
Characters: Similar to Oceanites oceanicus, but smaller; middle of abdomen white.
Adults (sexes alike): General dorsal color sooty black, or dark brownish black, usually darkest
on crown, lower back, and the quills of wing and tail; white upper tail coverts are partly obscured
by more or less white-tipped feathers of the rump, producing a somewhat lunate white patch or
band across the tail; wing coverts mainly like the back, but the median series somewhat grayish
brown, with narrow whitish edges in fresh plumage, these feathers, as wear and fading progress,
producing a rather conspicuous grayish or whitish wing-bar; primary coverts and quills of wing
and tail black, the lateral rectrices basally white on the shafts and inner webs; throat, chest, and
sides of body sooty brown, somewhat lighter than the back; middle of lower breast and abdomen,
and the entire vent, white, some of the feathers more or less smudged with sooty brown; the white
758 OCEANIC BIRDS OF SOUTH AMERICA
of the vent is continuous with the dorsal white band of the upper tail coverts; under tail coverts
sooty brown, the lateral feathers more or less white. Iris brown; bill and feet black, with a
triangular yellow spot on each web.
Females appear to average slightly larger than males, at least in the length of the wing.
Middle toe
Wing Tail Culmen Tarsus | vith claw
20, Peru (Chilca to Lobos de Tierra I.).} 123.5 55.5 11.1 30.5 22.3 mm.
20 9, Peru (Chilca to Lobos de TierraI.).| 128 56.6 11.1 29.6 22
Soha weys Ae Laake See 125.7 54.7 10.9 28.8 21.8
SOM Ghlee Sag At: etre das ak eae DO'S 54.3 ?: 29.2 22.2
Minimum of the series. ....... 117 48 10.5 28 21
Maximum of theseries ....... 132 le oe5i7 11.6 31.5 23
Distribution: Known from the Humboldt Current region of the west coast of South America,
between the latitude of Valparaiso, Chile, and Point Santa Elena, Ecuador.
The storm petrel originally described by Dr. Daniel Giraud Elliot, founder
of the department of birds in the American Museum of Natural History, is now
known to break up into two reasonably well-marked subspecies, of which the
typical form is a characteristic bird of the Humboldt Current region, along the
coasts of Peru, Chile, and southern Ecuador. Its nesting grounds, however, are
still undiscovered. The second and larger race is known only from the vicinity
of the Galapagos Islands, where it undoubtedly breeds, although the searching
of many visitors to that archipelago has not yet unearthed a single nest. The
Museum possesses excellent series of both forms.
Elliot's Petrel was collected in littoral waters practically throughout the
length of the desert coasts of Peru and Chile during the Brewster-Sanford Expe-
dition, besides which I subsequently obtained others in the course of my own
field work. On May 19, 1913, Mr. Beck came as close as possible to discovering
the nesting ground of this petrel, without actually being successful. In other
words, he found that birds taken off Ancén, Peru, had fully enlarged gonads,
and that one female carried in her oviduct an egg almost ready to lay. At the
neighboring Pescadores Islands, another species of storm petrel (Oceanodroma
tethys) had eggs in its burrows at this date, but a careful search by Beck dis-
closed no sign of nesting Elliot’s Petrels. Curiously enough, the latter was far
more common over the ocean around the Pescadores Islands than was the species
which proved to have its home there. Within a period of a week or more, Beck
collected 60 small petrels of various sorts a short distance off these islets; the
majority represented Oceanites gracilis, while only a single example was of the
resident species. I have noted a corresponding anomaly at the breeding grounds
of Leach’s Petrel (Oceanodroma leucorhoa) along the coast of Maine. For days
together not a single example of this abundant and resident petrel is to be seen
over the neighboring waters, while Wilson's Petrel (Oceanites oceanicus), which
comes as a migrant from the other end of the world, is present at all hours in
every cove and channel.
Beck’s Peruvian specimens of Elliot’s Petrel, which make up the bulk of our
BPLEILOd’s 8: 0TORM PETREL 759
series, were all taken fairly close to the continental coast, mostly within a
distance of 50 kilometers. He observed a few of the birds near the Hormigas
de Afuera Islets, which are 67 kilometers off Callao and which deserve a thor-
ough ornithological reconnaissance in a search for the unlocated nesting grounds
of several petrels peculiar to the west coast of South America. Farther out at
sea Beck makes no mention of Elliot's Petrel in these latitudes, but during a
subsequent voyage from Valparaiso to the Juan Fernandez group in the month
of December, he found it to be a common species at distances of 150 kilometers
or more off the coast of Chile. It is perhaps hardly likely that Mas Afuera may
yet prove to bea nesting station, but San Felix and San Ambrosio deserve further
investigation no less than Hormigas de Afuera.
It should be emphasized that the collections and observations of Beck and
myself were made at every season of the year, and that an egg was ready for
laying in the latter part of May, which is close to midwinter. Furthermore,
the birds in breeding condition were at the same time undergoing a moult of
the wing and tail quills at this season. Wetmore (1926, 53) also notes that a
number of Elliot's Petrels which came aboard his steamer to westward of Lobos
de Afuera Island, on May 7, 1921, had recently moulted the outermost primaries.
The four birds he captured were males. On deck they were helpless, and barely
able to walk with the aid of their wings. When handled, they uttered a low
chirping call.
Close to Lobos de Afuera I observed examples of this petrel on January 4,
1920, and about ten o'clock in the evening of a later day one flew into the state-
room of my steamer off Pimentel, Peru. Again, during the foggy night of Jan-
uary 15, 1925, I saw large numbers come on board another steamer 45 kilometers
due west of Pacasmayo. The rank odor of their regurgitated stomach oil made
the whole deck smell musky, and clung to the skin of my hand even after
repeated washings. Later in the same month I found these petrels very common,
off Point Parifias, the westernmost projection of the South American continent.
Here I saw great numbers of them flock into the wakes of two whales, which
were leaving oily streaks on the surface wherever they rolled out. My northern-
most record is of a bird observed at close range from a launch in the Bay of
Santa Elena, Ecuador, on February 11, 1925.
The stomach of a specimen I shot off the Chincha Islands, Peru, during
October, contained well-digested and unidentifiable animal tissue, together
with a considerable mass of fine cinders. The latter objects most of the storm
petrels seem to be fond of picking up from the surface of the ocean.
LOWE’S STORM PETREL
Oceanites gracilis galapagoensis
Oceanites gracilis galapagoensis Lowe, 1921, Bull. Brit. Orn. Club, 51, p. 140 (Charles Island, Galapagos
Archipelago).
Characters: Lowe's description points out the larger size of the Galapagos race, the ‘‘uniformly
lighter coloration, and the more diffuse and less conspicuous arrangement of the white on the
abdomen.”
760 OCEANIC BIRDS OF SOUTH AMERICA
Among the examples in the American Museum, and others examined at London, Berlin, and
Frankfurt, these characters hold in varying degree, that of size being quite constant. The average
length of the wing among 14 specimens of O. g. galapagoensis, for instance, is greater than the
maximum dimension among 46 specimens of 0. g. gracilis.
The average measurements of 14 adults from the vicinity of Charles, Albemarle, Indefatigable,
Abingdon, James, and Narborough Islands, collected during the months of February, March,
April, August, November, and December, are as follows:
2 ; Midd
Wing | Tail Culmen | Tarsus ise An
TOE Oe re ae eae gee 135.3 57 11.2 30.7 22.9 mm.
Minimum of theseries. ....... 130 53 10.5 28.5 21.6
Maximum of theseries ....... 146 60 | 12 32 24
The figures agree well with those of 85 specimens recorded by Loomis (1918, 182). The latter
show that, as in the Peruvian race, females average slightly larger than males. The length in the
flesh of 7 females ranged between 142 and 147 mm. The wing-expanse of 6 females was from 350-
370 mm., the average being 359 mm.
Distribution: The Galapagos Archipelago.
Loomis reports, upon the basis of collections and notes made during the
expedition of the California Academy of Sciences, that this storm petrel is
common throughout the year at the Galapagos, frequenting both the bays and
the open seas. It was never observed at a distance of as much as 100 kilometers
from the islands. No nesting places were discovered, but the gonads of these
birds were observed to have begun the enlargement incident to the breeding
season by the end of April. They were at their maximum in early July, and were
again reduced to the resting condition by November. The post-nuptial moult,
which involves the quills of wing and tail, takes place at the latter season,
namely between November and January. The petrels commonly came about the
schooner ‘Academy’ for refuse tossed overboard. The remains of very small
fish were taken from the stomach of one bird.
WHITE-BELLIED STORM PETREL
Fregetta grallaria grallaria
Procellaria grallaria Vieillot, 1817, Nouv. Dict. Hist. Nat., 25, p. 418 (‘Nouvelle Hollande’’ = west
coast of South America).
Names: Synonyms of the specific name include fregetta, segethi, lawrencit, and leucogaster although,
according to Mathews (1933, 41), the last should be regarded as a distinct species.
Characters: A square-tailed storm petrel with a wholly white belly and a conspicuous white
patch above the tail.
Adults (sexes alike): Grayish black with a brownish tinge, which increases with wear and
fading, on head, neck, upper breast, mantle, back and scapulars; the feathers of back and mantle
narrowly margined with white, which completely disappears as a result of wear; median wing
coverts grayish brown, broadly edged with whitish; lesser wing coverts and remainder of wing
black; rump and upper tail coverts white, a few of the feathers sometimes subterminally spotted
with black; tail quills black, the four lateral feathers basally white on the inner webs and shafts;
lower breast, abdomen, axillaries, and inner under wing coverts white, the marginal under wing
coverts black or blackish gray; sporadic blackish spots occasionally appear on the white feathers
of the crissum and lower flanks; under tail coverts black with white bases and occasionally with
narrow whitish tips. Iris brown; bill, legs, and feet black.
WHITE-BELLIED STORM PETREL 761
The following measurements show the size range within the typical race, and indicate that
females average slightly larger than males, which seems to be true of this entire group of petrels:
Middl
Wing Tail Culmen Tarsus aad ae
SE uscartidaccr ers ~eruiMs ms fees epee s 155.4 ¥ fo Po) 35 35 21.6 mm.
117 1.0 oy plo tofu lS elmo ae ee a" 156.4 73.5 13.4 35.6 Die
Minimum of theseries. ....... 146 71 12.6 33 20
Maximum of the series ....... 163 77 14 37 22.6
The downy young are thickly covered with long soft mesoptyles of Quaker drab color. Speci-
mens taken at Santa Clara Islet on January 19 are of different ages, some of them being almost in
the fledgling stage. The first contour plumage is like that of the associated adults, except that the
scapulars and wing coverts are very broadly edged with white. This same condition, however,
is found in new plumage of adult birds, the edgings subsequently disappearing through wear.
An egg from Santa Clara is elongate-ovate in form, dull white, with a sprinkling of faint pin-
point marks over most of its surface, and a heavy concentration of more definite marks, reddish
brown or vinaceous in color, at the apex at the larger end. These form not a ring but a patch
about 14 mm. in diameter. The egg measures 34.3 x 24 mm. Two others, of more nearly oval
form, have less dotting and measure 34 x 25 and 32.5 x 25 mm.
Distribution: Breeds at Mas Atierra and Santa Clara Islands, Juan Fernandez, and apparently
at San Felix and San Ambrosio Islets. Known also from various points off the Chilean coast, and
from the open Pacific ‘about 500 miles northwest of Mas Afuera."’
Juan Fernandez is now accepted as the breeding station of the typical race of
Fregetta grallaria. Hellmayr (1932, 416) is incorrect in stating that birds from
the Chilean coast are decidedly larger than those from Australian seas; the re-
verse is true among all specimens I have seen.
During the course of the Brewster-Sanford Expedition, in December, 1913,
and January, 1914, a series of more than 60 specimens of this petrel, most of
which are males, was collected by Beck off Valparaiso, Chile, and on and about
the islands of the Juan Fernandez group. Both eggs and half-grown chicks were
obtained at Santa Clara, or Goat Island, off the southwestern end of Mas Atierra,
on January 19 and 20.
Another adult in the Museum collection is the bird noted above as being
taken at sea far northwest of Mas Afuera. During the cruise of the “Zaca,’ Dr.
Chapin noted numerous examples within a day’s sail of San Felix Island, and
collected on February 17, 1935, a specimen which matches the Juan Fernandez
birds. Next day, about sunset, many more were observed in the waters close to
San Ambrosio. Representatives of the species, though probably not of the same
race, have been collected much farther northward, close to the Galapagos Is-
lands, as will be mentioned hereafter. Furthermore, Mathews (1933, 45) refers
to a skin in the museum at Stockholm labeled “‘Patagonia, February 20, 1850.”’
In its measurements the latter agrees closely with Juan Fernandez birds, but
Mathews'’s text does not indicate whether ‘‘Patagonia’’ means the Chilean or
the Argentine coast of the continent.
During the voyage between Valparaiso and Juan Fernandez in early December,
1913, Beck began to encounter White-bellied Storm Petrels before he was half-
way toward the nearer island. Many came astern of his schooner on December 4,
762 OCEANIC BIRDS OF SOUTH AMERICA
and he notes that, except when flying directly to windward, the feeding birds
would use only the leeward leg to maintain their momentum, kicking them-
selves into the breeze with this and holding the other stretched out behind. At
Mas Atierra he found the petrels foraging close under the cliffy shore during
rough weather, but when the sea was prevailingly calm he would encounter
them only sparingly within sight of land, and in cach greater numbers at a
distance of a day’s sail or more.
According to Lénnberg (1921, 10), the White-bellied are breeds at all the
islands of Juan Fernandez. Beck found the nests only at Santa Clara, where
they were under boulders close to sea level along the lee side of the island. Bent
(1922, 174) quotes as follows from Beck's notebook:
Though the fishermen of Juan Fernandez told me they had never found the nest of this bird I
found the nests quite close to the beach on Santa Clara Island, which lies about 10 miles from the
west end of Masatierra Island. The nests were usually in rock piles under a good-sized rock. The
few nests examined were lined with straws or a few twigs from bushes. One nest with its downy
occupant was plainly visible without moving the overshadowing rock. On January 19, 1914, the
date of my visit, I found more nests with young birds than with eggs. As with other species of
petrels the downy young of this species is left alone during the day.
Fledgling young of the Juan Fernandez birds are of a much darker gray color
than young in the same stage of the larger race which nests at Rapa Island in
southern Polynesia. The latter is the subspecies that I have described as Fregetta
grallaria titan, and it possibly enters our region in the Galapagos area. During
the cruise of the schooner ‘Academy,’ as recorded by Loomis (1918, 182), Mr.
Beck shot a White-bellied Storm Petrel in latitude 4° 20’S., longitude 93° 30’ W..,
on June 11, 1906. The position is southwest of the Galapagos and in the latitude
of Talara, Peru. The bird was not a stray, for no less than ten other examples
were seen in the same vicinity during the next few days. The specimen taken
was undergoing a complete moult. Its length in the flesh was 225 mm. and its
wing-expanse 480 mm. It has been measured both by Loomis and by Mathews
(1933, 45), and while the two sets of figures made from the same skin do not
exactly agree, they both indicate that the dimensions of this equatorial specimen
were considerably greater than the maximum among a large series of Fregetta
grallaria grallaria from Juan Fernandez. They are substantially the same, in fact,
as measurements of 27 birds from Rapa (Murphy, 1928, 5). Mathews apparently
regards the White-bellied Petrels occurring near the Galapagos as representatives
of the subspecies titan, but since I have seen no specimen I should prefer to let
the matter stand for future research.
TRISTAN STORM PETREL
Fregetta grallaria (tristanensis ?)
? Proc. aequorea Kuhl, 1820, Beitr. Zodl., p. 138 (off the mouth of the Rio de la Plata).
? Thalassidroma leucogaster Gould, 1844, Ann. Mag. Nat. Hist., 13, p. 367 (latitude 36° S., longitude 6° 47’ E.,
South Atlantic).
Fregettornis grallaria tristanensis Mathews, 1932, Bull. Brit. Orn. Club, 52, p. 123 (Inaccessible Island, Tristan
da Cunha group).
Names: Storm Pigeon at Tristan da Cunha. Synonyms for this form are uncertain, but melano-
leuca may be one.
TRISTAN STORM PETREL 763
Characters: ‘‘Head blackish; throat and upper chest dark blackish brown; the feathers of the
throat are uniform brown, those on the upper chest have white bases to the feathers; lower hind
neck, back and adjoining wing coverts dark brown, each feather with a white edge; some of the
primary coverts black with white edges to the feathers; primaries black, with white bases, the
smaller primaries and secondaries the same, but with a greyish wash; the secondaries have white
edges to the feathers; rump white, like the under surface from the chest to the vent; the vent
feathers are white with brownish black tips; the longer ones blackish with large white bases to
the feathers; some few are also tipped with white; tail even and black, the central pair all black,
the remainder with white bases on the inner web. The under aspect of the wing has the feathers
surrounding the bend of the wing from the axillaries to the primaries blackish, those immediately
above the primaries with white edges; remainder of the inner wing coverts white; under primary
coverts grayish, all but the first edged with white; the primaries show matt brown from the un-
derside, not black as from above’’ (Mathews, 1933, 45).
Total length, 193 mm. A discussion of other dimensions of this form is reserved for the fol-
lowing text.
Distribution: South Atlantic Ocean, breeding at one or more islands of the Tristan da Cunha group.
Despite the voluminous writings of Mr. Gregory M. Mathews in his ‘‘Birds
of Norfolk and Lord Howe Islands’’ (1928), ‘‘The Birds of Tristan da Cunha”’
(1932), and “‘On Fregetta Bonaparte and Allied Genera’’ (1933), I remain uncon-
vinced regarding the “‘generic’’ or even specific distinctions between the species
grallaria and leucogaster. Mr. Mathews's text makes very obscure and difficult
reading, being filled with inconsistencies and with somewhat misleading pre-
sentation of data. His detailed drawings of the legs and feet of the petrels of
this group show, in many instances, products as like as two peas except for
minute differences in scalation, relative length of claws, etc., such as one fre-
quently finds as individual or seasonal variations in any series of petrels. The
length and consequently the relative shape of claws, for example, depend very
much upon whether a petrel has recently been scratching out a nest-chamber or
whether it has been, on the contrary, months at sea. Furthermore, it is amply
shown by our large series of white-bellied storm petrels from several parts of the
world that the width of the white edgings on the feathers of the dorsal surface
varies greatly with wear, even among birds from the same breeding locality.
Yet Mathews makes the width of such edges a key character for discrimination
between two species.
In writing of the form of the White-bellied Petrel which inhabits Tristan da
Cunha, Mathews (1932, 25) has been guilty of publishing utterly misleading
text, for his account of the eggs and the plumage of young birds is set down with
scarcely any indication that the data refer to Juan Fernandez petrels and that
the text is, in effect, quoted from Bent. The eggs and young of the Tristan form
have not yet come into the hands of an ornithologist.
I have seen but one example of this petrel from the South Atlantic, namely,
a female with the following dimensions, which are uniformly larger than the
norm among eastern South Pacific birds: wing, 166; tail, 77; exposed culmen,
15.6; tarsus, 42.3; middle toe and claw, 28 millimeters. Combining these with
those of Tristan da Cunha birds recorded by Mathews (1933, 45 and 46), I
derive the following figures, based upon about seven adults; while the measure-
ments were made by several different persons, they give some sort of approxi-
764 OCEANIC BIRDS OF SOUTH AMERICA
mation of the size range: wing, 156-170 (162.7); tail, 71-82 (77.2); exposed
culmen, 14-15.6 (14.6); tarsus, 36-42.3 (38.9); middle toe and claw, 23-28
(24.8) millimeters.
According to Mathews (1933, 25), the ‘‘Storm Pigeon’’ is well known to
the people of Tristan da Cunha. Two skins to which he refers were taken at
Inaccessible Island on April 28, 1923. He concludes with the following some-
what inexplicable statements “’. . . no eggs have been sent as yet. The egg
is described as measuring 33.5x 25 . . . while the nest is of dry grass in a
burrow 18 in. long.”’
BLACK-BELLIED STORM PETREL
Fregetta tropica
Thalassidroma tropica Gould, 1844, Ann. Mag. Nat. Hist., 13, p. 366 (latitude 6° 33’ N., longitude 18° 6’ W.,
Atlantic Ocean).
Thalassidroma melanogaster Gould, 1844, Ann. Mag. Nat. Hist., 13, p. 367 (southern Indian Ocean).
Names: Except through misidentification, this species has been listed only under the specific
names tropica and melanogaster.
Characters: The longitudinal dark band on the belly, with conspicuous white areas on either
side, distinguish this storm petrel from its congeners. It is, however, surprisingly difficult to
differentiate in life as it follows a ship or dances upon the ocean.
Adults (sexes alike): Dorsal surface and also head, neck, and breast, sooty black, darkest on
the head; feathers of the back, scapulars, and median wing coverts narrowly fringed with white;
feathers of the middle of the abdomen, and the under tail coverts, terminally sooty black; upper
tail coverts, sides of body, and flanks white, as are also the inner under wing coverts and axillaries;
small coverts around the margin of the wing sooty black. Iris brown; bill and feet black.
6 specimens, including the type from the Atlantic: wing, 160-167 (164.3); tail, 73-77 (75.5);
exposed culmen, 15-16 (15.5); tarsus, 39-41 (40.1); middle toe and claw, 26-29 (27) mm.
Egg: Dull white, minutely and sparingly dotted with small pinkish or brownish spots, which
sometimes form a ring at the larger end. Examples from the Auckland Islands, New Zealand,
measure: 37 x 27 and 38.5 x 27 mm. (Oliver, 1930, 101). The average size of a number of eggs
from the South Shetland Islands was 36.5 x 26.1 mm. (Bennett, 1927, 79); a single egg from the
South Orkneys, 36 x 25.5 mm.
Distribution: Of pan-antarctic circumpolar breeding range, nesting in West Antarctica (South
Georgia, South Orkneys, and South Shetlands), the Falkland Islands (possibly), Bouvet Island,
the Crozets, Kerguelen, and some of the sub-antarctic islands south of New Zealand. Ranges
northward during migration into low latitudes of cool-current regions and, perhaps casually or
accidentally, into the northern hemisphere. Records of breeding at Ascension Island appear to be
without foundation. Those attributed to St. Paul and Amsterdam Islands in the Indian Ocean,
and to the Tristan group in the Atlantic, are open to serious doubt.
Fregetta tropica seems to be a thoroughly misnamed bird, for its entry into
tropical waters is doubtless only in the rdle of a migrant. As I shall show
below, all its known breeding grounds are in the far south. Sperling (1872,
75) understood this when he wrote that from its numbers and tameness this
bird might well be called the ‘‘sparrow of the South Atlantic’’; in lati-
tude 5° S., 30° W., he adds, about thirty of them were playing around his
ship, perhaps enticed northward beyond their normal range by food they
found in the wake.
Sheer juggling of scientific names has reached a climax in the taxonomic
BLACK-BELLIED STORM PETREL 765
treatment of the Black-bellied Storm Petrel. Statements regarding the range of
the bird which have no foundation in fact have been repeated many times in
the literature, and it has been intimated that there are two distinct subspecies,
one of tropical distribution and the other native to islands of high latitudes in
the southern oceans. Peters (1931, 70), by the way, has misquoted the type
locality of this petrel, placing it in latitude 33° N. near Madeira, whereas it is
in reality as indicated above in the citation of Gould's description, namely,
latitude 6° 33’ N., not far off the coast of Sierra Leone. Mathews’s (1933, 39)
statement that ‘‘this form does not appear to wander far from the type locality”
is made out of imagination, as is also his remark that it perhaps breeds at
Ascension Island.
Mathews is the latest reviewer of the group, and on page 41 of the paper
referred to he publishes an alleged key, designed to distinguish between a
tropical race (tropica) and a pan-antarctic race (melanogaster), the distinction
amounting only to size and extent of the dark stripe on the ventral surface.
After examining the type specimen, and a large number of others from many
parts of all the oceans, I am prepared to maintain that these differences are
purely individual or are due to wear of the plumage. Thus far no adequate
grounds for subspecific division of this petrel have been advanced. Neither is
there any tropical race breeding at Ascension or elsewhere. On the contrary,
the species is one belonging exclusively to the Antarctic Zone and the higher
latitudes of the Sub-Antarctic Zone. It is in effect a cold-water representative
of its near ally, the White-bellied Storm Petrel (Fregetta grallaria), which is
confined to lower latitudes and occurs as a breeder at islands close to the con-
vergence between sub-antarctic and sub-tropical waters.
The six Atlantic examples of the Black-bellied Storm Petrel I have examined
agree completely in appearance and measurements, except as regards slight
individual variation in the feathering of the throat and the extent of the dark
mark on the belly. One of these birds is the type specimen; a second is a British
Museum bird taken just south of St. Paul Rocks; a third is from South Georgia;
a fourth was captured west of the Cape of Good Hope, and the last two near
Cape Hoin. Dabbene (1922, 247) lists various other well-substantiated South
Atlantic records.
In the course of the Whitney South Sea Expedition, Mr. Beck collected a
large series of Black-bellied Storm Petrels in waters near latitude 49° S., longi-
tude 179° E., during the middle part of February, 1926. The locality is between
Bounty and Antipodes Islands. These specimens show a normal range of
variation, and they are indistinguishable, so far as I can tell, from South Atlantic
birds and from a single immature male collected by Beck off the coast near
Cafiete, Peru, on June 26, 1913. The last-named specimen has a slightly longer
tail than any of the birds from the New Zealand region, but the difference
seems insignificant. Furthermore, it has been pointed out that birds in juvenal
plumage frequently have longer rectrices than in their subsequent adult stage.
The measurements of the New Zealand birds show, moreover, that females
average slightly larger than males, a condition which has previously been noted
766 OCEANIC BIRDS OF SOUTH AMERICA
as a characteristic of this group of petrels. The following measurements are
important for comparison with those of Atlantic birds:
Wing Tail Culmen | Tarsus it 5 pas
DOG SAD Se 7 OC NEE ech ee ecko oe es 160 73.9 15.1 41.1 28.2 mm.
Minimum of theseries. ....... 154 7p 14 40 27.5
Maximum of the series ....... 167 ai 15.8 41.8 29
Bie OG Orubs Stns sn Mean oe 163.3 74 15.1 42.8 28.8
Minimum of the series. ....... 158.5 We. 14.5 42 27.5
Maximum of theseries ....... 167 76 Se) 43.5 29.6
oc immature, off Cafete, Peru... . 162 82 14.7 39 28
The nesting place of the Black-bellied Storm Petrel was first found at Ker-
guelen Island, where its habits have been studied by Eaton (in Sharpe, 1879,
131), Studer (1879, 109), Werth (1925, 592), and others. Subsequently it was
found breeding at South Georgia by the German Expedition of 1882-1883 (von
den Steinen, 1890, 242), and more recently at the South Orkney Islands (Clarke,
1913, 235) and the South Shetlands (Bennett, 1927, 79). Vanhéffen (1901, 310)
presents evidence to show that it is also a resident of Bouvet Island, in the waters
about which it was found abundantly during the month of November. Its
occurrence as a nesting species at the Falklands, as suggested by Bennett (1926,
313) and by the record of a supposed egg of this petrel obtained during the
‘Challenger’ expedition (Oates, 1901, 151), is open to doubt, while the repeated
statement that it breeds at islands of the Tristan da Cunha group has not yet
a leg to stand on.
The details of nesting at various islands between the Antarctic Archipelago
and the New Zealand region agree remarkably well. According to the nature
of the terrain, and the local temperature conditions, this Mother Carey's
chicken either burrows into the soil or nests among interstices of the rocks.
Thus at Deception Island of the South Shetlands, on January 13, 1927, Bennett
found the sites of the Black-bellied Petrels mingled with those of Oceanites
oceanicus under boulders of a talus slope in situations well sheltered from the
violent winds. No nesting material was used, unless the dead bodies of chicks
of earlier years can be classed as such. The egg, according to Bennett, is slightly
larger than that of Oceanites, or has at any rate greater bulk even though that
of the smaller petrel may sometimes ,be the longer.
At South Georgia the only known egg was taken on December 30, when
many pairs of the birds were still engaged in courtship proceedings. The first
South Orkney egg was discovered in a rock crevice at Laurie Island, 5 meters
above the sea, on December 5, by Dr. Pirie of the Scottish Antarctic Expedition.
The nest-cavity contained a fresh egg together with an addled egg of an earlier
year, an indication of the high mortality to which this species, as well as
Wilson’s Petrel, is subjected in regions which experience such extreme periodi-
cal cold as the South Orkneys. At Kerguelen eggs have been found between
January 3 and 30, and newly hatched young as early as January 25.
BLACK-BELLIED STORM PETREL 767
At the South Orkneys and many other localities, observers have referred to
the whistling sound which originally led to the discovery of the nest of this
petrel. The extraordinary notes are thus described in detail by Eaton, as he
heard them at Kerguelen Island:
Occasionally late in the evening and during the night a piercingly shrill piping note repeated
singly at intervals of four or six seconds used to be heard on the hills about Observatory Bay.
Generally the sound changed its direction, showing that the bird which uttered it was flying.
This call might be imitated on a piccolo fife in the key of G or F. In its complete form it consists
of a series of single notes separated by pauses of four seconds or more, followed by a jerky succession
of notes in the same tone.
One night the sound was traced to a crevice in a cliff beneath an immovable rock. The place
was marked by a pile of stones, and visited early the next morning. While efforts were being
made to move the rock the bird within the recess became alarmed, and uttered a cry somewhat
like that of a kestrel hawk in its tone, but not nearly so loud. On another night the sound was
followed up to a hill. Every now and then the bird ceased piping, but it recommenced whenever
the call was imitated with the lips. Its nook was therefore easily discovered (Sharpe, 1879, 131).
The noisy chorus apparently ceases or becomes greatly reduced in volume as
soon as the courtship season has passed, although Bennett states that a peculiar
whistle is uttered whenever the parent Black-bellied Petrels approach their nest
in the darkness.
There are few data on the food of this species, but Sperling (1863, 283) states
that off Cape Hanglip, to northeastward of Cape Town, the mouths of examples
captured on October 8 were filled with ‘dull ruddy spawn, which floated on
the surface of the sea all round us in large blood-red patches.”’
WHITE-FACED STORM PETREL
Pelagodroma marina marina
Procellaria marina Latham, 1790, Index Orn., 2, p. 826 (Southern oceans = off the mouth of the Rio de
la Plata).
Names: Frigate Petrel. Synonyms of the specific name include fregata, hypoleuca, and aequorea (?).
Characters: This petrel has the longest and heaviest legs among all the storm petrels, and also
the straightest bill, with the least pronounced unguis.
Adults (sexes alike): Crown, nape, and a broad infraorbital stripe which extends across the
cheek, dark mouse-gray, the stripe proceeding from a dense blackish spot in front of and partly
encircling the eye; back and wing coverts brownish gray (close to hair-brown in fresh plumage);
upper back and sides of breast somewhat grayer, whitish bases of worn feathers producing in some
instances a distinct light transverse mark between nape and back; rump and upper tail coverts
light neutral gray, forming a patch contrasting with the back and rectrices; tips of the upper tail
coverts, as well as those of the tertials, secondaries, and greater wing coverts, terminally edged
with white, a character which, however, rapidly disappears with wear; quills of wing and tail
sooty black, lighter on their concealed portions, the inner vanes of the remiges more or less flecked
with white; forehead, lores, and a broad supra-orbital stripe continuous with them, white except
for a few dusky feathers at the base of the culmen; ventral surface from chin to crissum, and like-
wise the wing-lining except for a few dark marginal feathers, white; under tail coverts white,
the longer and the lateral feathers somewhat flecked and barred with gray; a tuft of dusky feathers
on the thigh. Iris brown; bill black; legs and feet black, the webs yellow except at their edges.
3 specimens (sex unknown) taken from burrows on Nightingale Island, Tristan da Cunha group:
wing, 150-153 (151.7); tail, 71-75 (73); exposed culmen, 16-16.2 (16.1); tarsus, 40-42 (41.2);
middle toe and claw, 33-35 (34) mm.
768 OCEANIC BIRDS OF SOUTH AMERICA
Fledglings are clad in pale gray down, from which they moult into a plumage resembling that
of the adults.
Although I find no descriptions of eggs of the Tristan da Cunha race, those of other frigate
petrels have a fine white texture with little trace of gloss, and a varying amount of fine brownish
or vinaceous freckles, mostly toward the larger end. Measurements of 22 recorded by Bent, and
presumably from the eastern North Atlantic islands, average 36.2 x 22.03 mm.
Distribution: Breeds at islands of the Tristan da Cunha group; the Atlantic range is uncertain
because specimens upon which many records are based have not been critically studied. The
species is not known from Gough Island, the distributional status being sub-tropical rather than
sub-antarctic. Closely related forms are found in the eastern North Atlantic and the Galapagos
area of the eastern tropical Pacific.
The White-faced or Frigate Petrel has a wide distribution in the southern
hemisphere, and a race of the species also enters the eastern North Atlantic to
breed at the Cape Verde and Canary Islands. The subspecific status of examples
seen or collected in various parts of the South Atlantic has not been satisfactorily
determined. It is altogether possible, for instance, that birds frof northern-
hemisphere breeding grounds migrate to the coast of Argentina, for winter
journeys of similar type are freely made by certain other sea birds of the eastern
North Atlantic, such as the Manx Shearwater (Puffinus puffinus).
Dabbene (1922, 247) cites the known South American records from the neigh-
borhood of the Rio de la Plata, and from the offshore waters of Patagonia in the
latitude of the Gulf of San Jorge. One of these specimens represents the type of
the species, for it is of record that this bird, obtained during a voyage of Captain
Cook, was collected opposite the Plata estuary (Salvin, 1876, 228). Several
Frigate Petrels were seen by Aplin (1894, 212) at a point ‘113 nautical miles out
from Montevideo,’’ on June 10, or midwinter. The only other pelagic record I
can find for the South Atlantic is of an example that flew aboard the ‘Novara’ at
night, on September 16, 1857, in latitude 33° 49’ S., longitude 0° 43’ E., a posi-
tion slightly north and well to the eastward of Tristan da Cunha (Pelzeln,
1869, 144).
For the present, we may at least make the assumption that the generally
distributed South Atlantic Frigate Petrels are those which take their origin
from the Tristan group, where the ‘Challenger’ expedition obtained the first
examples from burrows at Nightingale Island on October 17, 1873. In the
British Museum I have examined three birds of this source, and find that they
appear to represent a race with well-marked differences from that inhabiting the
Cape Verde Islands, being of smaller size in most dimensions, particularly in the
length of the tarsus. It should be added that the subspecific characters of other
races of this petrel, in parts of the western Pacific for instance, exhibit still more
strongly marked differentiating characters both of a quantitative and a qualita-
tive nature. The generic group as a whole is much in need of revision. A recent
list, which recognizes four forms, is that of Peters (1931, 69), but this makes no
provision whatsoever, either by name or by an indication of range, for the repre-
sentatives of the species which have been taken in the neighborhood of Cocos
and the Galapagos Islands.
The Frigate Petrel, according to Thomson (1878, 157), is one of the ‘’Night-
WHITE-FACED STORM PETREL 769
birds’’ of the Tristan settlers. This visitor states also that the birds breed in the
wooded foreshores below the cliffs of Inaccessible Island, in the same territory
as that occupied by whale-birds (Pachyprila), and that they often make use of
abandoned burrows of other petrels. At Nightingale the ‘Challenger’ party
found, with the aid of dogs, the specimens mentioned above.
Mathews (1932, 23) reports that there is no recent information regarding this
petrel at the island of Tristan da Cunha itself. It is, however, one of the species
which would most quickly have been wiped out by the great invasion and
multiplication of rats, which ran its course at Tristan but which, fortunately,
has not affected Nightingale or Inaccessible. It is not clear from Mathews’s
text whether or not the egg description that he publishes is based upon speci-
mens from the Tristan group or those from some other part of the world. He is
incorrect, furthermore, in stating that Bent (1922, 179) gives measurements of
eggs of the ‘‘typical form."’ Bent, as a matter of fact, heads his biography with
the name of the North Atlantic race (Aypoleuca), but neglects to give any indica-
tion of the provenance of the eggs listed.
The following summary of the habits of the White-faced Petrel is based upon
observations relating to races in various parts of the world.
At sea these birds have an exceedingly erratic flight, and their long dangling
legs are conspicuous during the periods of their pattering upon the water. When
they flit over the land en route to their nesting grounds, they just “‘tip’’ it with
their toes, and bounce along, giving the impression of being full of springs.
Owing to the extraordinary length of their legs, they are about the most awk-
ward and helpless of all the Mother Carey's chickens when it comes to terrestrial
locomotion. Usually they make no sound while on the wing, but as soon as they
enter their homes a mouse-like squeaking begins to come forth, at least during
the breeding season (Littler, 1910, 160). They burrow chiefly in grassy areas
and in soft soil. In places where the population is concentrated, there may be
an entrance to a burrow in each square meter of the surface. It is estimated that
there are not less than 50,000 nests on Mud Island, off Port Phillip Bay, south
coast of Australia. Marking experiments show that during incubation by no
means all of the mated petrels are relieved in any one night. The young make a
purring note of welcome when the adult enters the burrow (Campbell and
Mattingley, 1907, 185).
Falla (1934, 247), who has recently made important biological studies upon
the habits of New Zealand sea birds, reports that the Frigate Petrels reappear
in his region about the middle of August, after an absence at sea of five months.
Egg-laying takes place during the last ten days of October, and the young hatch
at the end of November. The nestling down is of a uniform ash-gray, very long
and bushy on the pileum whereas the chin and throat remain practically naked.
The first teleoptyles begin to appear during January, and by March 1 the young
are flying. Diagnostic features of the juvenal plumage are the grayish edgings
of the secondaries, and the white tips of the longer wing coverts.
During September these birds of the islands off northern New Zealand ap-
proach closely to their ancestral breeding grounds, and engage more in mating
770 OCEANIC BIRDS:OF SOUTH AMERICA
activities, which include erratic pursuit flights, than they do in feeding. In
foggy weather during this period, many lose themselves and fly against light-
houses or fall on board passing ships. The burrows that these petrels subse-
quently make, or clean out, vary greatly in length. They use a larger quantity
of nesting material than most other species, which results in the egg being
kept especially dry and clean. A very few eggs are laid upon the surface of
the ground, and Falla has found at least one that had been well incubated
in such a situation. The Frigate Petrels come to their homes only after
dark, usually not sooner than an hour after the last trace of daylight.
When they arrive to feed the young they are not at first noisy, uttering
only a low twittering note while alighting. An hour or two before mid-
night, however, loud squeaking calls begin to issue from most of the
burrows. Only one adult has been found in the nest-chamber after the
hatching of the chick, and Falla believes that possibly only one of the parents
visits it during any one night.
Stomachs of incubating adults contained nothing but small pebbles. At
other seasons Falla has found cephalopod beaks in these petrels. The food-
contents of nestlings consisted mostly of a paste of minute crustaceans. Fledg-
lings ready to leave the nest discharged, when handled, about six cubic centi-
meters of clear reddish orange oil.
GALAPAGOS FRIGATE PETREL
Pelagodroma marina, subspecies
In the monograph on the avifauna of the Galapagos Islands by Swarth (1931),
no mention is made of the Frigate Petrel. I find, however, a number of records
and specimens which indicate that some form of the species is probably resident
in the eastern tropical Pacific not far from the coast of South America.
The first published notice is that of Loomis (1918, 182), referring to a speci-
men collected by Beck on June 18, 1906, in latitude 2° 40’S., longitude 91° 20’ W.
This position is due south of Albemarle Island. A second record is one of Beebe
(1926, 329) of an example which flew on board his ship in latitude 4° 30’ N.,
longitude 87° W., about 100 kilometers southwest of Cocos Island on a direct
line toward the Galapagos. In the Dwight collection of the American Museum,
there is a male bird marked ‘‘Chatham Island, Galapagos, December 15, 1905.”’
I do not know whether this was collected on the island or offshore. Finally, the
United States Biological Survey collection contains a specimen which flew on
board a steamer just west of Point Santa Elena, Ecuador, on the evening of June
23, 1922 (Wetmore, 1923, 171).
There is little to distinguish the eastern Pacific specimens I have seen from
Frigate Petrels inhabiting the South Atlantic. Their measurements are very
similar, the average of those of the two Galapagos birds and the one from
Ecuador being as follows: wing, 150.6; tail, 74.3; exposed culmen, 16.3; tarsus,
40.8; middle toe and claw, 36.2 millimeters. These figures are for the most
part strikingly smaller than the dimensions of North Atlantic specimens, but
GALAPAGOS FRIGATE PETREL 771
not unlike those of the three Tristan da Cunha birds I have examined. The
status of the eastern Pacific birds can only be determined by further research.
The stomach of the specimen collected by Beebe contained remains of insects,
the marine water-strider (Halobates).
THE DIVING PETRELS
FAMILY PELECANOIDIDAE
The diving petrels comprise a homogeneous, monogeneric, strikingly dis-
tinct group of Procellariiformes, the members of which exhibit few characters
that might indicate their relationships with other divisions of the order. They
have therefore always presented a somewhat puzzling problem to taxonomists.
The entire family has been mono-
graphed by Murphy and Harper
(1921, 495), whose study furnishes
the basis for the present treatment
of the South American species.
Confined wholly to the southern
hemisphere, where they are the bio-
logical analogues of the auklets and
murrelets (Alcidae) of the northern
oceans, the diving petrels have be-
come distributed through a broad
south-temperate and pan-antarctic
belt; one species alone has moved
its range northward into the tropics
along the west coast of America,
following the route by which pen-
guins, austral cormorants, and many
other cold-water organisms have
likewise entered the narrow, coastwise tongue of the Humboldt Current region.
Short-winged, characterized by ‘‘whirr-flight,’’ like that of the auklets,
rather than by gliding flight, and given to diving from above the surface of the
water, the Pelecanoididae have little resemblance to typical petrels. A corre-
lation between structure and their peculiar habits is evident in numerous mor-
phological details. Their nostrils point upward to an even greater extent than
those of shearwaters, and the nasal orifice is divided, and probably protected,
by a curious lateral flange. In the trunk skeleton, the sternum and rib-basket
have become extended further caudad than among petrels of other groups, pro-
ducing an excellent structural adaptation for plunging and subsurface progres-
sion, and resembling to a remarkable degree the condition in the auklets.
The entire distribution of the diving petrels, excepting the Humboldt Current
bird (Pelecanoides garnotii), is confined between the parallels of 35° and 60° S.
Excluding again the range of garnotii, practically all the regions inhabited by
Fic. 65. Sagittal section through the left narial
passage of Pelecanotdes garnotit, showing the para-
septal process (a).
From Murphy and Harper (1921)
772 OCEANIC BIRDS OF SOUTH AMERICA
diving petrels are characterized by tempestuous weather, a high scale of cloudi-
ness, and heavy precipitation. All the habitats, even that of garnotiz, are situated
in relatively cold oceans, in which the annual variation in surface temperature
nowhere exceeds 6.6° C. Furthermore, the shores of all the breeding grounds
are bathed by effluents of the west-wind drift, only slightly tempered, in a few
instances, by warm countercurrents.
Murphy and Harper (1921, 550) have shown that two of the most southerly
species of diving petrels have a more or less circumpolar distribution along
parallels of latitude, with widely separated races on or close to common isother-
mal lines. Representatives of all the known species, except Pelecanoides exsul
of the southern Indian Ocean, occur within the American region. P. georgicus
belongs to the Antarctic Zone, P. urinatrix and P. magellani are sub-antarctic,
while P. garnotit occupies the continental littoral of western South America.
Alone of all the family, the last-named species inhabits a mild region of rain-
less, relatively placid seas, with an invariable surplus of accessible food. The
factors which inhibit increase of size in the more southerly species are appar-
ently not effective, and this largest and most northerly of diving petrels has,
moreover, overcome the limitations of a fixed breeding season, and has assumed
the continuous breeding habit common to many sea birds of tropical latitudes.
Throughout the whole family of diving petrels there is a tendency toward
decrease in size with decrease in temperature of the habitat, an apparent con-
tradiction of the correlation expressed in Bergmann's law, which has been dis-
cussed in the life histories of the penguins.
The forms of diving petrels living at remote oceanic islands, such as georgicus,
exsul, and most of the races of wrinatrix, appear to make migrations of consider-
able extent, or at least to lead pelagic lives during part of the year. The con-
tinental species, garnotit and magellani, on the other hand, seem to be strictly
littoral and practically sedentary. Neither of these two latter species has been
recorded from any offshore locality; P. garnotii is unknown at Juan Fernandez;
P. magellani has not invaded the territory of its near neighbor, P. urinatrix
berard, which nests at the Falkland Islands. Further evidence of the permanent
residence of garnotii and magellani within the environs of their breeding ranges
is to be found in their notably uniform plumages, a condition contrasting
strongly with the wide amplitude of individual variation in P. georgicus, for
instance. This is in accord with the recognized principle that, other factors
being equal, so-called stationary species exhibit a lesser degree of individual
variation than species which undertake long periodic migrations.
Murphy and Harper have presented evidence that the diving petrels are of
American origin. All the species except P. exsul are indigenous within a rela-
tively short distance of the southern extremity of South America. It would
seem as though the agencies which have been determining the course of evolu-
tion within the family have been most active in the region referred to, and that
the point of original dispersal may not have been far from Cape Horn. In this
locality we find today Pelecanoides magellani, the most strongly marked and
distinctive of all diving petrels, and in this sense the most advanced member
THE DIVING PETRELS 3
of the genus. The more distant Pelecanoides garnotii has, except for its increase
in size, differentiated much less from the family type. Still more distant and
isolated examples, such as Pelecanoides georgicus, P. exsul, and the remote races
of P. urinatrix, share with one another strong superficial resemblances of color
and pattern, small size, etc., which are probably due not to close relationship,
nor to convergence, but rather to the retention among these peripheral forms
of primitive, non-adaptive characters. In any group of organisms, we should
look to the point of origin for advanced present-day types rather than for
primitive present-day types, and, upon this criterion, southern South America
fulfils the requirements.
POTOYUNCO
Pelecanoides garnotit
Puffinuria Garnotii Lesson, 1828, Manuel d'Orn., 2, p. 394 (coast of Peru, north of San Gallan Island).
Names: Garnot’s, or Peruvian, Diving Petrel; ‘‘Potoyunco,’’ presumably of aboriginal source,
is the vernacular name in Peru and Chile. An untenable race has been described under the sub-
specific name /essont.
Characters: The largest member of the family; nearest to P. magellani, but much larger, espe-
cially in length of bill, wing, and tarsus. Bill relatively slender in proportion to length (exposed
culmen exceeding twice the width of bill at base); outline of combined nasal orifices broad and
cordate, the walls of the tubes horny and firm, the nostrils appressed; claws relatively blunt and
stout. Natal down whitish.
Adults (sexes alike): Upper surface black, each feather with a terminal band of glossy black,
preceded by a grayish black area, which shades into the grayish white basal portion; the shafts
mostly dark; scapulars mostly dusky neutral gray on outer web, grayish white on inner web, more
or less concealed by the plumage of the interscapulum, but forming in many specimens an irregular,
blotchy diagonal stripe; wings glossy black, more or less tinged with brownish, especially on
primaries; secondaries narrowly tipped with whitish; inner webs of primaries clove-brown; under
wing coverts whitish, more or less washed with light mouse-gray, the shafts mostly dark; rectrices
glossy black, fading to glossy brownish black, paler on the under surface; anterior part of forehead
and lores suffused with clove-brown; under surface white; auriculars and malar region chaetura
black; a fuscous area extending from the sides nearly to the middle of the breast, and sometimes
extending entirely across as a faint mottling; axillaries dark mouse-gray to black; sides and flanks
strongly washed with deep mouse-gray, the feathers sometimes narrowly tipped with whitish;
feathers of tibia mouse-gray; down plumules and aftershafts over entire body deep mouse-gray.
Paraseptal processes situated at the longitudinal center of the septum. Bill black; iris brown;
tarsus and toes bluish; webs black.
20 males: length (skins), 217-238 (228.7); wing, 130-141 (136); tail, 33-43 (36.7); exposed
culmen, 19-22 (20.4); width of bill, 8.5-10.5 (9.6); depth of bill, 7-9 (8.3); tarsus, 30-34 2.9);
middle toe and claw, 34-39 (36.9) mm.
20 females: length (skins), 209-239 (221.9); wing, 130.5-144 (136.6); tail, 33.5-41 (36.5);
exposed culmen, 19-21 (19.7); width of bill, 8.5-10 (9.2); depth of bill, 7-8 (7.6); tarsus, 32-34
(32.5); middle toe and claw, 34.5-40 (36.3) mm.
The natal down of the newly hatched Potoyuncos is very light colored, between pale gull-gray
and white. It is attached to the tips of the mesoptyle down which is mouse-gray, but which fades
appreciably before it is finally moulted. The first contour plumage resembles that of adults. Im-
mature examples are, however, apparently determinable even when they are more than a year old,
for while at this age they have mostly acquired new quills, the rectricial moult is often still in-
complete, and one or more of the bleached tail quills, abraded as only the plumes of young petrels
are wont to be, contrast strongly with their heavily pigmented successors. Such old rectrices are
much more weathered and frayed than the corresponding year-old feathers of adult birds.
774 OCEANIC BIRDS OF SOUTH AMERICA
Egg: Six collected at San Gallan Island, Peru, on July 4, 1913, range in form from short-ovate
to elongate-ovate, one being extremely pointed at the smaller end; white, thin-shelled, lustreless;
Measurements, 48.5 x 33.6, 46 x 34.5, 46.7 x 34.2, 48 x 37, 47 x 34, 45 x 33 mm. (average, 46.8
x 34.4). Average volume of the six, 24 cubic centimeters. Egg measurements recorded by Coker
(1919, 465) entirely agree with these.
Distribution: Endemic in the Humboldt Current; western coast of South America, from Lobos
de Tierra Island, Peru (latitude 6° 27’ S.), to Coronel, Chile (latitude 37° S.), and casually farther
southward.
The Potoyunco, like the Pajaro Nifio or penguin, has suffered a great dimi-
nution along the coasts of Peru and Chile owing to the transformation brought
about on the rocky islands by removal of the ancient blanket of guano. Early
recorders, such as the Peruvian naturalist Raimond, credited these curious sea
birds with being highly important producers of guano in former times. About
the middle of the last century they inhabited the Chincha Islands, and other
groups off the central part of the Peruvian coast, in vast hordes. They no longer
nest commonly upon any of the low islands which are regularly worked for their
guano accumulation, because most of the surface into which the petrels are
capable of burrowing is gone, leaving only a thin crust of guano upon the
native rock. Since the condition applies to nearly all the islets of the west
coast, between northern Chile and Lobos de Tierra, it is probable that only a
few high islands, which have considerable sand and soil upon their tops and
flanks, now afford homes to the bulk of the surviving population of Diving
Petrels. Such lofty islands include San Lorenzo, Fronton, San Gallan and
Vieja, in Peru. Paessler (1922, 440) and Stresemann (1922, 130) report that this
Diving Petrel also breeds, in all probability, at Santa Maria Island in the Bay
of Arauco, Chile, a point which apparently marks the southern limit of its
nesting range.
At Vieja Island, which forms the outer barrier of Independencia Bay, I first
found the Potoyunco’s nests, at altitudes of between 180 and 300 meters, during
November, 1919. The burrows were not evenly distributed, but made scattered
colonies, like the settlements of kangaroo-rats or other desert rodents. They
were always in soft soil at this locality, never piercing the crust of alkaline
salt which formed the walls of many crests and gulches. Moreover, they were
all situated on windward, that is, southerly, exposures, and wherever an east-
to-west ridge cut across the island, the burrows on more northerly ridges were
invariably enough higher to raise them out of the lee. Such choice of sites,
determined by the prevailing wind, doubtless gave the Potoyuncos an advantage
in taking flight from their thresholds, a feat perhaps more difficult for them
than for longer-winged petrels.
During the same month I also visited the mountainous island of San Gallan,
off Pisco Bay, Peru, which is close to the type locality of this petrel. As I stood
at the very summit of the island, where the aneroid registered an altitude of
402 meters, and looked down the slopes and valleys, the most striking marks
were the innumerable clusters of black specks which represented the round
mouths of Potoyunco burrows. The aggregate number of birds on this island
must be enormously great in spite of Condors, *‘Gallinazos’’ or Turkey Vultures,
POTOY UN CO 775
marauding fishermen, and the “‘zorras’’ or wild dogs, which occur only upon
San Gallan of all the Peruvian islands. From a meter or so above sea level to the
pinnacles, in the damp soil of seepage areas behind the beach, in the detritus at
the base of the precipices, on the hard upper slopes of the hills, and in the midst
of the succulent vegetation of the cloud zone, the island is indiscriminately
drilled full of holes. By day there are nothing but burrows and bones to suggest
the existence of the Potoyuncos, and the large proportion of empty nests might
give even a naturalist the impression of extinction; but at night the air rings
with their purring voices and vibrates with the whirring of their wings.
I remember vividly the evening at San Gallan when, on strolling from the
campfire to the base of a hill which rose from the beach, I first became aware of
the living presence of myriad ghostly creatures which were soon determined to
be Diving Petrels. Out of the talus came low, froggish songs. Whichever way
I turned along the slope, the chorus of elfin voices continued to resound in my
ears. When] fetched a lantern I soon found the crevices that led to the burrows,
for the weird songs were not interrupted even by a light at the entrance, and
flying birds, perhaps attracted by the glare, fluttered past and darted into the
ground. It was not practicable to get at the nest-chambers here, because of the
protection afforded by the rocks, so my Peruvian companions and I made a trip
in the darkness to the entrance of a flat valley. Except where the earth was
encrusted with salt, we could now dig into the petrel homes very easily, and
we captured a dozen or more specimens. The tunnels were variable in course
and depth, but most of them led down steeply from the entrance for about 30
centimeters before beginning their level, twisted path to the enlarged nest-
chamber. The blissful singing of the birds continued while the digging pro-
gressed, but when they were hauled out they screamed angrily. A few of the
burrows proved to be empty, but within most of them we found either a bird
and an egg, a bird and a chick, a chick alone, or two adults. The noisiest holes,
if they may be so described, usually contained a love-making pair without egg
or offspring. When the captive birds were put into a burlap sack, some of them
resumed their song, but not so contentedly. All the while additional Potoyuncos
were streaming in from the sea.
During the course of the Brewster-Sanford Expedition, Mr. Beck observed
and collected Potoyuncos during nearly every month of 1913. The localities
mentioned in his notebook include Salaverry, Ancén, Callao, Chilca, various
parts of Pisco Bay, Arica, Iquique, Taltal, and Valparaiso. On October 22 he
ran out to sea ina motor-boat from Corral, the port of Valdivia (latitude 40° S.),
but could not find a single example of the species. Paessler (1922, 440) however
reports that this species of Diving Petrel was observed by him southward to the
latitude of Ancid, Chile, or almost to 42° S. He records the birds also from
Coronel, Corral, Taltal, and Islay. Among the large number of specimens I have
examined, are examples from Coquimbo, Chile, and from the following Peruvian
guano islands, at all of which the Potoyunco formerly nested abundantly:
Lobos de Tierra, Macabi, Guafiape, Pescadores, and Ballestas. Beck found a
single family breeding on one of the Pescadores Islands on May 8, 1913.
776 OCEANIC BIRDS OF SOUTH AMERICA
Nothing is known about a regular migration of the Potoyuncos and it is
probable that their movements are mainly sporadic, as are those of most other
endemic birds in the Humboldt Current where the physical environment is so
little related to latitude. One sees them chiefly in small groups on the water,
or flying just above it for distances of 100 to 200 meters. They seem usually to
be working to windward, but since the breeze on the coast of Peru is nearly
always from a southerly quarter, it is clear that the birds must also travel north-
ward, either during the almost daily calm periods or along tracks farther from
the coast. Perhaps there is sufficient directional compensation in the fact that
both wind and current tend to carry them rapidly northward while they float
on the surface.
Paessler states that during the southern summer the Potoyuncos are more
common in the Peruvian and Chilean bays than in winter, when many of them
go 10 to 20 kilometers offshore. Beck, however, found them still farther from
the coast of Peru in January, which is midsummer. All observations agree that
the species is at all times confined to the zone of cool, upwelling water, rela-
tively close to the land.
The Potoyuncos often concentrate with other oceanic birds about the shoals
of anchovies and silversides (Atherinidae), with which their stomachs are
sometimes found to be crammed. Furthermore, they congregate in areas of
ocean water discolored by clouds of Munida or other free-swimming crustaceans.
Of twelve stomachs of the birds which I submitted to the United States Bio-
logical Survey, the majority contained only traces of gravel and a varying
content of small crustaceans, identified merely as the megalops stage of a crab.
More than 120 of these organisms were in one stomach. Beck found that
the Diving Petrels paid little or no attention to the bait which he often
spread on the water.
In common with many other native sea birds of the Humboldt Current, the
Potoyuncos breed throughout the year. In early July, at San Gallan, Beck took
adults on their nests, both fresh-laid and heavily incubated eggs, and chicks
varying in age from a few days to several weeks. Coker and I each found eggs
and young at other seasons.
The courtship of the species has not been reported, although Paessler ob-
served a pair chasing each other in circles on the surface of the bay of Taltal.
Their nest-chambers are usually lined with a few feathers, sometimes derived
from other species of birds, but the probable use of such objects in the courtship
behavior is still unverified. The eggs I have seen have in common with those of
most petrels a remarkable variation in shape. In volume, however, six of them
are relatively uniform, the average contents being 24 cubic centimeters. Four
eggs of the South Georgian Diving Petrel (Pelecanoides georgicus) average only
16.2 cubic centimeters, and those of most forms of P. urinatrix are apparently of
about the same bulk. The period of incubation of the Potoyunco is not known.
Beck observed in more than one instance that Diving Petrels and Inca Terns
shared a common entrance, leading to their respective nests.
How little the Potoyuncos are dependent upon the power of flight is shown
POTOYUNGO TTh|
by the fact that they moult their wing quills all together, and thus for a time
each year become exclusively aquatic. A study of the large series in the Brew-
ster-Sanford collection indicates that normally a complete moult occurs between
August and October. Most of the November specimens are in new bright plum-
age, while from this month forward the series as a whole shows progressive
wear of the feathers up to and including the following winter season (July).
The stomachs of the naturally ‘‘crippled,’’ temporarily penguin-like Diving
Petrels, which have lost all their flight feathers, prove to be as well filled with
crustaceans or small fishes as those of their flying contemporaries. They capture
their prey by making shallow dives, apparently effected without any preliminary
leap into the air like that of cormorants, grebes, etc. Beneath the surface they
literally fly with their wings, whether or not the remiges are full-sized, and they
remain under water for only relatively brief periods; a considerable series of
observations which I made showed that the birds were ordinarily below for
lengths of time varying between three and twenty seconds. Thus, so far as
feeding is concerned, they might just as well be flightless birds. The only
indispensable use of full-grown primaries would seem to be to bear the Poto-
yuncos to and from their nesting burrows on the islands.
Little is known of the natural enemies of the Peruvian Diving Petrels while
they are at sea, but Paessler saw one being persecuted by either a skua or a
jaeger. The petrel dived as often as its enemy swooped at it, but the outcome
of the attack was not observed.
The following is abridged from Coker’s (1919, 462) excellent account of the
Potoyuncos, as he observed them during nearly two years’ field work along the
coast of Peru.
In favored locations on the islands they are breeding at all seasons and the guano left in their
subterranean chambers is considered particularly rich in nitrogenous matter. My first acquaintance
with these birds was when at night in a small boat we often sailed close by them floating on the
surface of the water. On the islands, as far as my observations go, they are strictly nocturnal,
coming and going only after daylight has gone and before the light of morning. They are more
readily recognizable by sound than sight, and, as they fly obscurely about over the island, uttering
their little croaks, they are very suggestive of bats.
The nests are made in the side of the hill, often just beneath a large rock or sheltered under the
hard salty crust. It is an odd experience to sit at such a place and hear the mysterious sounds from
subterranean homes. Over and over again, with the voice of a frog, unvaried in pitch or rhythm,
they repeat the sequence of notes—two longs, a short and a long, the last note slightly longer than
the first two. Another more complicated sound is made by some and it is possible that the calls
are distinctive of the sexes.
The potoyunco is comparatively small, measuring about 10 inches in full length from end of
bill co tip of tail and weighing half a pound. The body is thickly covered with feathers, beneath
which is a thick gray down, the dense coat making the bird appear to possess a very large body.
Viewed from below, the body is oval in form—like a large white egg—the wings and the short,
stout neck seeming disproportionately small appendages.
A number of the nests were observed at the Ballestas North Island, and the birds were heard
on the Chinchas, but the lofty San Gallan was the chief island for potoyuncos, as the potoyuncos
were easily the principal bird of this large island.
San Gallan, 2.5 by 1.5 miles, is mostly dry, barren, and dusty, but with high hills reaching
well into the clouds, and only there, in the moist altitudes, teeming with plant life. Everywhere
778 OCEANIC BIRDS OF SOUTH AMERICA
over the island are large spots perforated by the holes of the potoyuncos, as they undermine the
hard, dry crust of the lower hillsides or burrow back underneath the vegetation of the cloud-
wrapped peaks more than a thousand feet above sea level.
Searching for these birds in the daytime one is guided only by the openings of the burrows,
for their voice is rarely heard during the day. One may try quite a number of nests without result,
as the burrow may either be unoccupied or, more often, too deep for the arm to reach to the nest.
Still, so abundant are the nests on San Gallan, that a considerable number of birds or eggs may be
captured in an hour or two. Once reached, the birds are easily taken, as they make almost no effort
at resistance. Sometimes, after they are out, they try to bite, but without inflicting injury. Occa-
sionally they would rush into the hands held at the mouth of the burrow.
At night it is much easier to take them, when guided by the voices one may avoid exploring
the unoccupied homes. It is thus that the laborers and fishermen catch them abundantly, for the
potoyunco is valued for food in fresh or salted condition.
If liberated they run rapidly over the ground flapping their wings, but unable to rise except
after a run of 10 or 20 feet. Then, with exceedingly rapid movement of their short wings, they make
for the ocean with a queer zig-zag flight. Reaching the ocean they fly low over the water a little
distance, settle upon the surface, and then swim away with short, shallow dives.
When placed on the ground in my tent, the petrels displayed peculiar movements. The body
is covered with a very thick coat of feathers so that lying on the ground the body seems to flatten
out remarkably, while the wings, pushed a little out on the sides, increase the apparent width
until the body has quite a turtle-like form. As they crawl rapidly along, the legs are spread well
out to the sides and the body is barely, if at all, lifted from the ground. I noticed that with some
the body was slightly raised; with others not at all. In any case the movement is a reptilian creep
rather than a walk. When I started one under my sleeping bag it began to burrow, with strong
backward sweeps of the feet, used alternately and sending the dirt flying with great force. Two
birds were placed outside in holes in the ground, each secured by a line attached to the leg. They
made a little effort to burrow, but soon stopped. At 10 o'clock at night I found them trying to
go toward the water. Placing them back in the holes I left them again, hoping to ascertain the
rate of excavation. Unfortunately, in the morning only the bones of the legs remained, and the
tracks of gallinazos accounted for the disappearance of the birds.
Presumably both condors and gallinazos (buzzards) may be accounted enemies of the poto-
yuncos, although their subterranean life and nocturnal flights give them substantial protection
from predatory birds. Certainly the chief enemy is man. About the signs of old campfires number-
less wings of the potoyuncos were often observed. For a while I was puzzled by the many signs of
sacks having been dragged down the hillsides, until it was observed that these trails led in almost
every case to the grounds where there were burrows of potoyuncos, even to those near the very
tops of the peaks. The ground was not torn up as if guano had been the object of search, and the
abundant evidence of discarded wings of potoyuncos completed the story. The fishermen assured
me that these birds were very good when salted, and that the laborers on the islands regularly
brought back quantities of potoyuncos salted down.
A “‘pichon,”’ or fledgling, at the stage when the wing feathers are first appearing, is a large
shapeless mass of fat and down, with nearly the dimensions of its parents and of equal weight
(about 7 ounces). Its soft coating of gray down measures 3-4 cm. in thickness. Ifa single tuft of
down is pulled out, there is found growing out of the blue sheath the delicate feather, which for
about 1 cm. is white (if from the lower side of the body) or black Gif from the back); many of
its barbs are tipped with delicate plumes of down, which are dark gray for about 2 cm. and possess
white tips of 1 cm. length. The head protruding from the great ball of down appears almost
bald having only a close crop of gray down.
Valued as they are for food and readily open to capture, the potoyunco must eventually be
brought near to extinction unless effective efforts for its protection are made. It will be unfortunate,
indeed, if the potoyunco and the penguin, two water fowl which produce a fertilizer of high quality,
shall, through mere human negligence or wastefulness, become lost to the guano industry. Valu-
able the potoyuncos may be as food, or the penguins for the skins or fat, and we may impose little
personal blame on those who desire the food or the skins or the oils; but the fact remains that
POTLOY,UN GEO «; 779
when the food or the skin and oil is taken the bird is lost to the future, while the removal of the
guano is a benefit gained without loss. With due care each of these important species may not
only be preserved to the future, but may be restored to a condition of far greater abundance and
value than at the present time.
MAGELLANIC DIVING PETREL
Pelecanoides magellani
Puffinuria garnotii magellani Mathews, 1912, Birds Australia, 2, p. 239 (Strait of Magellan).
Names: Magellanic, or Fuegian, Diving Petrel; ‘‘Petrel Zambullidor’’ is the South American
book name. The species has been reported upon in the literature under several other specific names,
such as urinatrix, berard, garnotit, and tenuirostris, of which only the last is a true synonym.
Characters: Nearest to garnotii in general form of bill, to wrinatrix in size. Differs from all other
members of the family in the possession of white tips to feathers of back, upper rump, and wing
coverts (in fresh plumage), and in having a conspicuous falcate whitish area extending from the
side of the neck to the occiput; the upper breast, moreover, is always pure white (never crossed
by a mottled collar). Bill relatively slender in proportion to length (exposed culmen about equal
to twice the width of bill at base); walls of the nasal tubes moderately thin and often somewhat
warped in dried skins; nostrils widely divergent posteriorly. Claws relatively sharp and slender.
Natal down unknown.
Adults (sexes alike): Upper parts glossy black; feathers of the back and upper rump with nar-
row white tips, which disappear with wear (showing best in August specimens, entirely absent
in some March specimens); scapulars dusky neutral gray (lighter on the inner web), with a terminal
band of white (broader on the inner web); the scapulars forming a broken but distinct diagonal
stripe of white; wing coverts and secondaries glossy brownish black, the former with narrow, the
latter with conspicuous, white tips and edges, which largely disappear with wear; primaries black-
ish brown, slightly glossed, becoming paler on the inner web; under wing coverts white, a few
feathers near the edge of the wing with dark shafts and splashed with blackish mouse-gray;
rectrices black (fading to blackish brown), paler on the under surface, and several of the lateral
feathers with narrow white tips, which disappear with wear; lores and anterior part of forehead
suffused with clove-brown; under parts white, cheeks and sides of neck dark mouse-gray, the feath-
ers with narrow white tips, except in worn plumage; a more or less distinct patch of white, falcate
in shape, behind the cheeks, extending from the throat to the occiput; axillaries varying from dark
to blackish mouse-gray; sides and flanks washed or broadly banded with dark neutral gray, the
feathers with white tips, and the shafts black subterminally; feathers of tibia fuscous; down plu-
mules and aftershafts over entire body deep neutral gray. Paraseptal processes situated posterior
to the longitudinal center of the septum and not prominently developed. Bill blackish; iris brown;
tarsus and toes bluish, webs black.
20 males: length (skins), 204-218 (209.8); wing, 120-133.5 (125.7); tail, 36-44 (40.5); exposed
culmen, 15-17 (16); width of bill, 7.5-9 (8.1); depth of bill, 6-7 (6.4); tarsus, 26-30 (28.1);
middle toe and claw, 31-36.5 (34) mm.
20 females: length (skins), 197-227 (208.5); wing, 121-132.5 (128); tail, 34-43.5 @9.3);
exposed culmen, 15-17 (16.2); width of bill, 7-8.5 (7.9); depth of bill, 6-7 (6.2); tarsus, 27.5-
29.5 (28.2); middle toe and claw, 31.5-36 (34.1) mm.
The eggs and chicks of this species are apparently still undiscovered.
Distribution: Patagonian, Fuegian, and southern Chilean coastal and inland waterways, from
Cape Horn northward on the Atlantic side to the vicinity of Puerto Deseado, and on the Pacific
coast to the Gulf of Anciid and other waters around Chiloé Island.
The Diving Petrel inhabiting the complex of Fuegian waterways is a very
well-marked species, probably the most distinctive and certainly the hand-
somest representative of its family. It is surprising that so many naturalists
should have confounded it with the smaller and more plainly colored species,
780 OCEANIC BIRDS OF SOUTH AMERICA
P. urinatrix, until Mathews, as recently as 1912, distinguished it, and yet sig-
nally failed to recognize its proper rank, by describing it as a subspecies of
Pelecanoides garnotit.
In the revision by Murphy and Harper, and in Peters’s ‘‘Check List’’ (1931,
76), Trinidad Channel, in latitude 50° S., is given as the northern limit of the
range of this species on the Pacific coast of South America. Since my former
study, however, I have examined in the Zodlogical Museum of Berlin two
males of this species collected by Plate in December, 1894, bearing upon their
respective labels the locality names of Calbuco and the Gulf of Ancid. Strese-
mann (1922, 130) identifies these two birds as specimens which had been
erroneously reported as P. garnotii by both Plate and von Schalow.
In the same paper Stresemann refers to an example taken by Paessler in the
Atlantic on June 17, 1913, in latitude 49° S., longitude 65° 3’ W., at a point
177 kilometers off the Argentine coast. Furthermore, Tschudi (1844, 46 and
308) long ago testified that this or another species of diving petrel was a common
bird in the Bay of San Carlos, on Chiloé Island.
The best published account of the Magellanic Diving Petrel in nature is still
that of Charles Darwin, who supplied Gould (1841, 138) with the following note:
This bird is common in the deep and quiet creeks and inland seas of Tierra del Fuego, and on
the west coast of Patagonia, as far north as the Chonos Archipelago. I never saw but one in the
open sea, and that was between Tierra del Fuego and the Falkland Islands. This bird is a complete
auk in its habits, although from its structure it must be classed with the Petrels. To the latter
Mr. Gould informs me, its affinity is clearly shewn by the form of its beak and nostrils, length of
foot, and even by the general colouring of its plumage. To the auks it is related in the general form
of its body, its short wings, shape of tail, and absence of hind-toe to the foot. When seen from a
distance and undisturbed, it would almost certainly be mistaken, from its manner of swimming
and frequent diving, for a grebe. When approached in a boat, it generally dives to a distance, and
on coming to the surface, with the same movement takes flight: having flown some way, it drops
like a stone on the water, as if struck dead, and instantaneously dives again. No one seeing this
bird for the first time, thus diving like a grebe and flying in a straight line by the rapid movement
of its short wings like an auk, would be willing to believe that it was a member of the family of
petrels. . . . I observed at Port Famine, that these birds, in the evening, sometimes flew in
straight lines from one part of the sound to another, but during the day, they scarcely ever, I
believe, take wing, if undisturbed. They are not very wild: if they had been so, from their habit
of diving and flying, it would have been extremely difficult to have procured a specimen.
Reynolds (1934, 333) also likens the Magellanic Diving Petrels to grebes.
He writes of three which he watched swimming in still water off the Isla de los
Conejos, near the western end of Beagle Channel. They glided through the
water almost without leaving a ripple. When they took flight, however, they
seemed to leave the surface with difficulty and only by beating the wings ex-
tremely rapidly. In the air, with the head erect and the body drooping some-
what more than is common with sea birds, they reminded the observer of a
small rail.
The general likeness of the diving petrels and the auklets has been mentioned
in the literature many times since Darwin wrote the paragraph quoted above,
but it was not until the time of the Brewster-Sanford Expedition that the strik-
ing resemblance between the plumage of this species (Pelecanoides magellani) and
MAGE EEANTSG DIVING PETREL 781
the winter plumage of the Dovekie or Little Auk (Alle alle) was fully recognized.
The remarkable similarity between these two unrelated birds involves not only
size, the approximate proportions of the limbs and tail, and absence of the hind
toe, but also the color and texture of the whole dorsal and ventral surfaces, the
common possession of a falcate white area at the sides of the neck, and the
presence of white markings on the proximal flight feathers and their coverts.
Indeed, the homoplastic resemblance of the Fuegian Diving Petrel and the Dove-
kie constitutes one of the best examples of convergent evolution known among
vertebrates.
Mr. Beck saw a great deal of this Diving Petrel during his several wanderings
among the intricate Magellanic channels, where he collected 78 specimens. He
did not succeed in finding an egg or nestling, although on Hermite Island, just
northwest of Cape Horn, a dog scratched at a crevice under a large boulder, and
Beck believed that a Diver was nesting within. A native sealer told him that
he had once found a nest of this bird on one of the islands to westward of Cock-
burn Channel. It was 100 meters or more above sea level, and was unearthed
by his dog while they were searching for otter holes on a rocky hillside.
At the western end of Cockburn Channel, in the vicinity of the Horn, and off
the east coast of Patagonia, Beck often saw birds of this species flying straight-
away for long distances—quite out of sight, in fact. This does not support
Nicoll’s (1904, 47; 1909, 180) opinion that their flight is a feeble fluttering, and
that they are much less strong-winged than the Diving Petrels of Tristan da
Cunha. Beck reports that when the Magellanic birds fly low they sometimes
strike the crests of choppy waves, being checked for a moment in their course
and then recovering. His notes further state that this species does not feed in
flocks like the whale-birds (Pachyprila) but, rather, individually or in very
small, scattered groups. They appeared to feed particularly in ‘‘streaks’’ on
the water caused doubtless by the effluvia of their prey. Beck occasionally saw
single birds pop into flight from beneath the surface. The stomachs of some that
he shot were distended with invertebrates. Nicoll found small fishes in examples
taken in Molyneux Sound.
The following notes are extracted from Mr. Beck's Journal.
Magallanes, July 8 and 9, 1914. Diving petrels scattering; about thirty collected in the strait
north of the town.
Nov. 17. Coming by steamer from the Atlantic into the Strait of Magellan; a few diving petrels
off Cape Virjenes. Within the strait they were much less common than they had been three months
before.
London Island, at the western end of Beagle Channel, Nov. 30. Diving petrels came into the
protected bay for shelter from a williwaw; several shot.
Caroline Island, Dec. 7-14. Two diving petrels collected.
Lort Bay, False Cape Horn (Hoste Island), Dec. 26. Out in boat for two hours, and shot
twenty diving petrels, which were common. Many came into the bay from the northward to feed.
Between Hermite and Wollaston islands, December 28. One diver seen.
London Island, Jan. 18, 1915. Rain and squalls all day, but diving petrels did not come into
the bay as they usually do in such weather. Only one seen and collected.
Junction of Beagle Channel and Magellan Strait, western Tierra del Fuego, Jan. 21. A few
diving petrels seen.
782 OCEANIC BIRDS OF SOUTH: AMERICA
Thirty kilometers north of Magallanes, March 6. Fifteen or twenty shot.
Lort Bay, April 7, 8, and 9. Where dozens of diving petrels had been seen in ee only
one was noted during these three April days.
Lort Bay, April 20. Two seen.
At sea, 125 kilometers east of San Sebastian Bay (east coast of Tierra del Fuego). High south-
west winds. Three diving petrels seen.
Off Rio Gallegos, Patagonia (95 kilometers north of the eastern entrance of the Strait of Magel-
lan), May 11. Strong south wind. Diving petrels were common offshore in the heavy sea.
Between Rio Gallegos and Rio Santa Cruz, May 24. Many diving petrels among other fishing
birds, 30 kilometers offshore.
Six kilometers off Cape Virjenes, May 26. Two diving petrels noted.
Strait of Magellan, east of Magallanes, June 11. A few diving petrels seen.
Ushuaia, Beagle Channel, July 15 (midwinter). One or two seen.
False Cape Horn, July 25. Two seen.
Off the mouth of the Rio Gallegos, Argentina, Aug. 8. A strong offshore wind, and a swift
tide, during the forenoon. Several diving petrels were noted, keeping within five kilometers of
the land.
At sea, 80 kilometers northeast of Rio Gallegos, Sept. 10. Three or four diving petrels seen.
At sea, 60 kilometers east of Puerto Deseado, Sept. 13. Two seen.
At sea, lat. 48° 27’ S., 65° 36’ W., Sept. 15. Several diving petrels collected.
Punta Delgada, Strait of Magellan, Oct. 4. Many diving petrels flying within the Strait.
The Brewster-Sanford series of Pelecanotdes magellanit comprises specimens
collected during the months of January, March, July, August, September,
November, and December. Adults shot in November and December had en-
larged gonads and bare brood-patches; a female taken at London Island on
November 30 contained an “‘egg
ready to lay within two days.”
By March some of the young
birds leave the nest. A fledgling
female collected at Magallanes
on March 6, 1915, shows the
diagnostic characters of the spe-
cies, z. e. the very black dorsal
surface, pure white throat, fal-
cate area behind the cheeks, and
broad white edgings on the
proximal wing feathers. Itlacks,
however, the beautiful white
terminations of the dorsal body
feathers, which markings are
thus proved to be indicative of
Fic, 66. Dorsal and ventral aspects of the bill maturity. Fledglings have,
in four species of Diving Petrels, drawn to the moreover, weak bills and small
same scale. Specific differences are revealed in the claws such as are characteristic
form of the mandibular rami and nostrils, the ae young Procellaritanmecnen
position of the paraseptal processes, etc. <
Reading from left to right: upper row, Pele- general.
The annual moult of the Mag-
canoides garnotii, P. magellant; lower row, P. : ee : :
georgicus, P. urinatrix. ellanic Diving Petrel is carried
MAGE LLANE, DIVING,PETREL 783
out between the first of April and the end of June. Four specimens taken in
July are all in very bright plumage, with new quills and with the delicate,
white, lunulate terminal markings distributed all over the interscapular region
and upper rump.
From July onward the abrasion of the plumage is so uniform that it is easy
to guess, with approximate closeness, the dates of capture of individual speci-
mens merely by noting the condition of their plumage. March birds are rela-
tively worn and dingy, and in nearly all instances the white edgings on the
back have entirely disappeared.
The series of nearly a hundred specimens which I have examined includes
birds from the coast of Chiloé Island, from Antonio Islet in Trinidad Channel,
from Molyneux Sound, from five insular localities close to Cape Horn, from
various parts of the Strait of Magellan, from the inland body of water known
as Ultima Esperanza, and from the Atlantic coast of southern Patagonia. The
series presents considerable evidence that the young birds do not moult their
contour feathers during the first season. Specimens taken during December, the
beginning of southern-hemisphere summer, for instance, are of two kinds,
namely, birds with moderately worn plumage which are evidently adults, and
others with feathers very much worn and frayed which I judge to be the young
of the preceding breeding season. Some of the latter examples have particularly
ragged quills and they all lack the white interscapular markings. The plumage
sequences in this species therefore appear to be virtually the same as those of
Oceanites oceanicus, the commonest migratory petrel of the North and South
Atlantic (Murphy, 1918, 118).
SOUTH GEORGIAN DIVING PETREL
Pelecanoides georgicus
Pelecanoides georgica Murphy and Harper, 1916, Bull. Amer. Mus. Nat. Hist., 35, p. 66 (Cumberland Bay,
South Georgia).
Names: Diver is the whaleman’s name at South Georgia. In the literature this species has been
listed under the technical names wrinatrix, exsul, and berard, from all of which it is in reality distinct.
Characters: Size small, approximating that of some of the races of P. urinatrix; bill proportion-
ately wider at the base, and tapering more sharply, than in other Pelecanoididae (width at base
equal to three-fifths of exposed culmen); nasal eminence thin-walled, the shape of the oval, closely
appressed nostrils in dried skins always more or less altered by shrinking. Mottling of jugulum
decidedly variable, becoming very pronounced in some specimens. Natal down gray.
Adults (sexes alike): Upper parts glossy black; scapulars grayish white, with an obscure sub-
terminal band of deep neutral gray, broader and slightly darker on outer web; the scapulars more
or less overlaid and concealed by the dark interscapulars, but forming in many specimens a broad,
conspicuous diagonal stripe; wings glossy black, more or less tinged with brownish, especially on
primaries; secondaries generally edged narrowly with whitish, and primaries becoming pale on
edge of inner web; under wing coverts white, sometimes mottled with pale neutral gray, and the
shafts sometimes dark terminally; rectrices blackish brown, with a slight gloss, paler on the under
surface, and the worn lateral feathers sometimes showing whitish edges; anterior part of forehead
and lores suffused with clove-brown; under parts white; cheeks and sides of neck deep neutral gray,
the feathers narrowly tipped with white; this gray mottling varying much in intensity and diseri-
bution, and in some specimens extending completely across the jugulum; axillaries, sides. and flanks
barred more or less strongly with neutral gray, the feathers tipped with white; feathers of tibia
784 OCEANIC BIRDS OF SOUTH AMERICA
deep mouse-gray; down plumules and aftershafts over entire body varying from deep mouse-gray
to dark mouse-gray, with lighter tips. Paraseptal processes situated at the longitudinal center of
the septum. Bill black, rami of mandible slaty; iris seal-brown; tarsi and toes flax-flower blue;
webs black.
100 males: length (skins), 193-218 (202.6); wing, 104-122 (112.7); tail, 34-42 (37.7); exposed
culmen, 14-16 (14.9); width of bill, 8-10 (8.9); depth of bill, 5.5-6 (5.8); tarsus, 22-26 (24.4);
middle toe and claw, 27-33 (30.1) mm.
85 females: length (skins), 181-215 (198.2); wing, 104-120 (113.8); tail, 34-43 (38.2); exposed
culmen, 14-16 (14.7); width of bill, 8-9.5 (8.8); depth of bill, 5-6 (5.7); tarsus, 21-26 (24.2);
middle toe and claw, 26-32 (29.9) mm.
In the nestling young the protoptyle down is light mouse-gray on the upper surface of the body,
pallid mouse-gray beneath, where it is also much shorter than above; throat and sides of head
nearly bare. Mesoptyle down drab-gray; longer, less dense, and of looser texture above than on the
ventral surface. Contour feathers appearing first on the bare parts of head and throat, then on
wings, tail, and back. Down lost progressively from head, wings, back, flanks, and breast, cling-
ing longest on the belly, and fading decidedly with age.
Egg: Ovate, short-ovate, or oval; pure white, lustreless; measurements of 4 are 38.5 x 32,
39 x 30, 39 x 31, 41 x 32.3 (average, 39.4 x 31.3) mm. Average volume of the 4, 16.2 cc.
Distribution: A species of the Antarctic Zone of surface water, known only from South Georgia,
where it is abundant, and from Macquarie Island, southwest of New Zealand. Only two or three
examples have been recorded from Macquarie, but these have all the specific characters of georgicus,
and are quite distinct from P. urinatrix of neighboring islands.
During my expedition to South Georgia, Divers were first observed at sea in
latitude 50° 12’ S., longitude 34° 47’ W., on November 20, 1912. This is about
450 kilometers north of the island. None was noted again until February 24,
1913, when many were seen at dusk in the main channel of the Bay of Isles,
South Georgia.
On February 27 a breeding colony was discovered in a broad valley which runs
eastward from the head of Possession Bay between two high, symmetrical moun-
tain peaks. The floor of the valley is partly of broken stone, partly grassy, with
some water-saturated moss and several glacier streams. Pelecanoides burrows
were distributed from the shore of the bay to the higher slopes more than
3 kilometers inland, not only on banks and knolls, but also on the flat itself,
wherever a little bed of clay and sand covered with vegetation was raised above
the general stony level. The excavations were hardly larger than field-mouse
holes, at least at the entrance (7 centimeters in diameter, according to von den
Steinen); but some of them were as much as 2 meters in length. As a general
rule, they first led down steeply and then ran horizontally but with sharp
lateral turns. Some tunnels were doubled back almost on their own tracks, and
often there was a diverticulum just outside of the nest-chamber. Here and there
a burrow ran beneath a roof of the tangled roots of a rosaceous herb (Acaena
adscendens). It frequently happened that the course was changed by stones
encountered during the digging; and that the nest-chamber lay under a stone.
The chambers were unlined except for a little down and an occasional bit of
lichen, perhaps introduced by accident. Most of the nests contained well-grown
young, a few of which had all but lost the down. Each of two nests dug open
on March 3 held one adult bird, but neither egg nor young.
All the young Divers found were exceedingly fat, except for one or two poor
SOUTH GEORGIAN DIVING PETREL 785
starvelings which were reduced to a condition of mere feathers and bones, and
which had crawled to the mouths of their burrows in vain expectation of their
parents, when no doubt the latter had been accounted for by some skua (Cath-
aracta) days or perhaps weeks before. Other nests contained emaciated dead
young, and told of the consummation of similar tragedies.
During a snowstorm on the evening of March 13, two Diving Petrels, dazzled
by a lantern, flew on board our vessel which lay at anchor in Possession Bay.
The captain of a Norwegian ‘‘floating whaling-factory’’ informed us that when
he had moored his steamer in Possession Bay one January night, the decks had
suddenly swarmed with Divers attracted by the lights.
The discovery of a representative of Pelecanoides georgicus at Macquarie Island
(Murphy and Harper, 1921, 525) is of exceptional interest from several points
of view. In the first place, South Georgia and Macquarie Island are situated on
almost exactly opposite sides of the South Pole, and are nearly 13,000 kilometers
distant from each other across the South Atlantic and Indian Oceans along the
parallel of latitude. Though both are situated at the same latitude, South Geor-
gia lies within and Macquarie Island outside the extreme limit of pack-ice.
It is not unlikely that additional representatives of georgicus may yet be dis-
covered at such high-latitude islands of the Antarctic Zone as the South Sandwich
group, Bouvet, and Heard, when these are sufficiently explored. Wilkins (1923,
485) has already observed the species in numbers southeast of Clerke Rocks, and
the ‘Scotia’ expedition encountered Diving Petrels in latitudes 51° to 52° 31’S.,
longitude approximately 9° W.
During my stay at South Georgia I collected a series of specimens, which was
subsequently added to by Mr. José G. Correia, an account of whose field work
has been given in Part I. More than 250 examples of this species were examined
by Dr. Harper and me during the preparation of our review of the family.
Divers were observed on the fiords of South Georgia throughout the year by
members of the German ‘Transit of Venus’ expedition. Matthews (1929, 579)
also reports that they can be seen during every month, all of which indicates
that the entire population never migrates away from the vicinity of the island.
The return to the breeding grounds begins in November, all activity ashore
being carried on during the hours of darkness. Such nocturnal habits may be
primitive rather than due exclusively to the presence of the skua, but in any
event the latter enemy must be an important selective factor in preventing any
variation in behavior. Nothing is known of the courtship of this Diving Petrel.
The excavation of the long burrows through hard, stony, often frozen soil is a
tremendous task, accomplished entirely at night by the employment of both the
bill and the strongly clawed feet. Before dawn the birds discontinue their labor
and retreat to sea. That numbers of them are nevertheless captured by the skua
is indicated by dismembered skeletons on the ground in the neighborhood of
the colonies.
New burrows were noted by von den Steinen (1890, 240) on November 24,
the more nearly completed among them being occupied by pairs of birds. On
December 8 he found the first eggs, each covered by a parent alone in the nest-
786 OCEANIC BIRDS OF SOUTH AMERICA
chamber. Nesting material is rarely used, and the egg quickly becomes dis-
colored from the bare, usually wet soil. Newly hatched young have been found
between January 22 and February 13. After the chick is a few days old, it is left
quite alone in the burrow between daylight and dark. The young birds are
bundles of down, and they squat with their heads drawn against the back so
that bare areas on the throat and face are covered and protected (Matthews,
1929, 579). By March 15 they are mostly well feathered, and by the end of the
month they have all grown up, lost their down, and taken to sea. The last
chick in a large colony was observed by von den Steinen on March 29.
Growth and moult of the downy coats of young birds are well illustrated by
a graded series of chicks collected between February 8 and March 15. The small-
est specimen (110 millimeters in total length) is clothed with short, straight
protoptyles, varying in color from pallid mouse-gray beneath to a slightly
darker gray above. The dorsal down is much longer; the throat and the sides
of the head are practically bare. The next specimen is evidently considerably
older (185 millimeters in length), and is clad in long, dense, rather curly mesop-
tyle down, drab-gray in color and of looser texture above than below. The
contour plumage is appearing in the form of pin-feathers on the bare throat and
cheeks, and the primaries have sprouted to a length approaching 30 millimeters,
although the rectrices have scarcely punctured the skin. It is interesting to note
that the last tufts of much-bleached mesoptyles cling to the center of the belly,
where they serve as a cushion or mattress until the nestling has attained practi-
cally its full development.
One of our fledglings, taken from the burrow, had lost the last trace of its
down as early as March 15. The juvenal plumage is indistinguishable from that
of breeding birds, except that no mottled areas on the jugulum are to be seen
among our series of fledglings, and the brownish tinge on forehead and lores is
usually fainter and less extensive than in adults. Young birds taken after they
have left the nesting grounds are at once determinable, however, because of
their weak and slender bills.
I found-no food substances within the stomachs of South Georgian Diving
Petrels, but only occasional pebbles. A stomach preserved in alcohol contains
four fragments of clay-slate, the largest of which measures 10 x 6 millimeters.
Matthews lists their food merely as “‘small planktonic animals.’ Andersson
(1908, 57) found a green paste which he identified as plant tissue, but which was
more probably animal food colored by bile.
On March 15, 1913, when my vessel, the brig ‘Daisy,’ stood to sea from Pos-
session Bay, South Georgia, I fortunately had occasion to make a trip in a
whaleboat to a neighboring whaling station for the purpose of posting mail.
Shortly after sunset we started on a two-hours’ pull to the brig offshore, and
as soon as we were well beyond the mouth of the bay our boat was continually
in the midst of innumerable small Tubinares flocking over the calm dusky sea.
Oceanites, Fregetta, Daption, and Diving Petrels made up the bulk of these birds,
which fluttered all about us like bats. Diving Petrels also covered the water in
swimming flocks, and often took to flight at the approach of the boat, usually
SOUTH GEORGIAN DIVING PETREL 787
diving again within a short distance. In spite of the diminutive size of their
wings, they seemed to fly at very high speed. Von den Steinen also writes of
endless files of Divers and other small petrels which he saw streaming out to sea
from Royal Bay during a January evening of 1881. Regarding the speed of these
birds in both the air and the water, Matthews says that they literally fly from
one into the other as though the two mediums were one.
With reference to the relation between the Diving Petrels and their principal
enemy, the skua, enough has been said elsewhere. The advent of man at
South Georgia has, however, brought an even more insidious foe, for in the
subterranean runways of introduced rats great quantities of cleanly picked
Pelecanoides bones have been found.
Murphy and Harper have taken advantage of the extraordinarily large series
of these nesting petrels from a single island to make a detailed study of variation
within the species. As regards color pattern they find a wider amplitude than
in most other forms of Pelecanoides with respect to the mottled collar crossing
the jugulum. Among some specimens of P. georgicus this makes a complete and
pronounced band, while others have entirely white throats, and still others
exemplify intermediate conditions. The variation is purely individual, for no
correlation is determinable between it and sex, age, season of capture, or state
of plumage.
A statistical study of measurements of birds taken on successive dates between
November 29 and February 28 indicates that there is no tendency for the younger
or yearling Diving Petrels to reproduce earlier or later than their elders. Such
seasonal differences, associated with difference in age, are observable among
certain larger Procellariiformes, such as the Wandering Albatross. In the case
of Pelecanoides georgicus, however, the nesting season, which is definite and closely
tied in with the climatic cycle, is evidently uniform for all the breeding members
of the population.
Measurements of 100 breeding male Diving Petrels, and of a slightly smaller
number of breeding females, indicate that the range of variation in the size
of wing, tail, bill, leg, and foot agrees closely with what is known of similar
variability among other petrels. As expressed in percentage of the average
dimensions, the maximum amplitude among 185 South Georgian Diving Petrels
was as follows:
; é Exposed Width of bill Middle toe
Wing Tail culmen at base Tarsus and claw
16.0 23.6 13.6 22.5 20.7 20
A comparison of complete skeletons of Pelecanoides georgicus and the Dovekie
(Alle alle) emphasizes more fundamental proportional resemblances than those
already referred to in comparing the external likenesses of the Dovekie and the
Magellanic Diving Petrel. The similarities apply to the size and proportions
of practically all elements of the axial skeleton and the appendages. Further-
more, the expanded wing surface of an adult of Pelecanoides georgicus totals 69.7
square centimeters, that of an adult of Alle alle 64 square centimeters. These
figures emphasize an extraordinary degree of convergence, for the Diving Petrel
788 OCEANIC BIRDS OF SOUTH AMERICA
is a small-winged extreme within its own order of birds, while the Dovekie is
a relatively large-winged member of the auk family. That the differentiation
represented by the wing of Diving Petrels lies in difference of feather propor-
tions, rather than of skeletal proportions, is shown by a comparison of the
several elements in Pelecanoides georgicus and in two species of long-winged petrels.
FALKLAND DIVING PETREL
Pelecanoides urinatrix berard
; eral Berard Gaimard, 1823, Bull. Gén. et Univ. Ann. et Nouv. Sci., 3, p. 53 (at sea near the Falkland
Islands).
This form is one of three subspecies of the Australasian Diving Petrel which are supposed to
occur within the field of this book. I give, therefore, the original reference to the typical form:
Procellaria urinatrix Gmelin, 1789, Syst. Nat. 1, pt. 2, p. 560 (Queen Charlotte Sound, New Zealand).
Names: Diver and Fire-bird in the Falkland Islands. In the literature the Falkland race has
been listed under the names wrinatrix, berard, berardi, and even garnoti1.
Characters (of the species wrinatrix): Size approximately that of Pelecanoides magellani. Bill
relatively stout and blunt, tapering abruptly near the tip, but almost as wide in the middle as at
the base owing to the expansion of the lateral elements of the maxilla and the bowing of the
mandibular rami (exposed culmen about equal to twice the width of bill at base). Rami nearly
parallel for the greater part of their length, but converging abruptly toward the tip, enclosing an
obtusely pointed interramal space. Nasal eminence thin-walled, the shape of the elongate, reni-
form, closely appressed nostrils in dried skins always more or less altered by shrinking. Natal down
silver-gray above, and white on ventral surface.
Adults, of the typical race, P. urinatrix urinatrix (sexes alike): Upper parts glossy black;
scapulars deep neutral gray, with a whitish terminal bar; wings glossy black, more or less tinged
with brownish, especially on primaries; inner webs of primaries clove-brown, lighter on under
surface; secondaries sometimes narrowly tipped with whitish; under wing coverts whitish, more
or less washed with light mouse-gray, the shafts dark; rectrices glossy black, fading to blackish
brown, paler on the under surface; anterior part of forehead and lores suffused with clove-brown;
under parts white; feathers of auricular and malar regions, and sides of neck and breast, deep
neutral gray, forthe most part narrowly tipped with white, giving a somewhat barred appearance;
jugulum obscurely mottled with neutral gray, which sometimes forms an indistinct collar; axillaries
dark mouse-gray, tipped with whitish; sides and flanks washed with deep neutral gray, the feathers
tipped with whitish; feathers of tibia dark mouse-gray; down plumules and aftershafts over entire
body deep mouse-gray. Paraseptal processes situated posterior to the longitudinal center of the
septum and not prominently developed. ‘‘Irides and bill black; legs and feet cobalt, tinged with
green, the webs bluish white’’ (Buller).
Subspecific characters of P. urinatrix berard: Size approximating that of P. u. urinatrix, but
generally with smaller bill, longer tail, and longer middle toe and claw. The mottling across the
jugulum is more pronounced than in P. w. urinatrix, less pronounced than in P. u. dacunhae. Iris
brown; bill black; feet blue with blackish webs (R. H. Beck, label).
4 males: length (skins), 195-227 (208.2); wing, 117.5-125.5 (121.1); tail, 39.5-46 (42.7); .
exposed culmen, 15-16 (15.5); width of bill, 7-8 (7.4); depth of bill, 6-6.5 (6.2); tarsus, 24.5-27
(25.7); middle toe and claw, 32-36.5 (33.4) mm.
3 females: length (skins), 198-201 (199.3); wing, 117-123 (120.5); tail, 40-44 (41.5); exposed
culmen, 15.5-16 (15.7); width of bill, 7.5-8 (7.7); depth of bill, 6; tarsus, 25-25.6 (25.2); middle
toe and claw, 32-33 (32.5) mm.
Egg: Two collected at Kidney Island, Falklands, in November, 1915, are respectively rounded-
ovate, or almost subspherical, and elliptical-ovate; white, lustreless; measurements, 35.2 x 31,
38.8 x 29.5 (average, 37 x 30.3) mm. Average volume of the two, 16.7 cubic centimeters.
Distribution: A sub-antarctic form, which nests at the Falkland Islands and ranges northward
to the coast of the Province of Buenos Aires, Argentina.
FALE LAND-DIVING PETREL 789
Pelecanoides urinatrix, the fourth species of Diving Petrel occurring in the
American region, is represented by subspecies at the Falklands and at Tristan
da Cunha, and apparently by a third among the Magellanic islands of southern
Chile.
During the course of the Brewster-Sanford Expedition, Mr. Beck obtained
five adult examples and several eggs at the Falklands. I have examined seven
other specimens, including two taken off the Argentine coast, between the Gulf
of San Matias and Necochea. The latter locality is north of latitude 39° S.,
and not very far from Mar del Plata. Paessler (1922, 441) reports seeing Diving
Petrels during the southern-winter season all the way along the coast of Argen-
tina from latitude 40° S. to the Strait of Magellan. Two specimens he obtained
in this part of the Atlantic were identified as of the species wrinatrix. He ob-
served several at least 160 kilometers from land. It would seem as though the
oceanic ranges of P. magellani and P. urinatrix berard must partly overlap, and
it is tempting to speculate as to why the birds of the two species return to
mutually exclusive nesting territories. Paessler believes, indeed, that this species
may breed on islets along the Atlantic coast of Patagonia, as well as in the
Falklands, but of this we have no direct evidence.
The last-named observer kept a number alive on shipboard for several days.
The petrels remained very quiet when confined in a dark space, but were at
once attracted toward lights, which verifies the statements of Falkland sealers
that the Divers will fly like moths into the flames of a fire at night. Paessler’s
captives proved silent but not particularly shy, and they would swim in a
bath-tub in search of bits of fish and mollusks which, however, they did not
seem to relish.
Beck saw a single Diving Petrel about 120 kilometers due south of the Falk-
land Islands on one of the latter days of September, 1915. On November 6, of
that year, he visited Cochon Island, East Falkland, and found the first burrow,
which contained a male Diver sitting upon a heavily incubated egg. On the
same date he also landed at Kidney Island, which is but 6 kilometers from
Cochon, and found a second burrow in a patch of tussock grass (Poa flabellata)
not far from the water. By digging and pulling out the manure-like humus
around the nest, he managed to obtain a photograph of the sitting bird. The
entrance to the nest was under a slab of rock, but the tunnel twisted about for
a meter and ended in an enlarged chamber which was lined with a few dry
blades of tussock grass. On November 18 he captured three more Diving Petrels
in their nests cn Kidney Island. He discovered, moreover, that abandoned
Pelecanoides burrows are used as nesting sites by the small, dendrocolaptid
““tussock-bird’’ (Cinclodes).
On December 16, at Sea Lion Island, he found the foot and leg of a Diving
Petrel within the stomach of a Short-eared Owl (Asio flammeus sanfordz).
Since information regarding the life history of this and other New World
races of Pelecanoides urinatrix is so scanty, it will be of interest to summarize
an excellent study made by Falla (1934, 246) on islets off northern New
Zealand. In this region the annual moult of the Diving Petrels is completed
790 OCGEANIC BIRDS OF SOUTH AMERICA
in March. From April onwards, large flocks of birds in fresh plumage gather
at sea near the breeding grounds. For fully three months many of them
come ashore at night and clean out last year’s burrows. Odd birds, usually
males, sometimes remain in the diggings throughout the day during this
period. The sex organs begin to enlarge in April, although no eggs are laid
before July, from which time they continue to be deposited in the burrows
until the end ot August. Incubation requires at least five weeks, and the
young remain about seven weeks in the nest. (These periods fit in with
what little is known of the succession among American species, such as
Pelecanoides georgicus, although the breeding season of the latter is much
closer to southern midsummer. )
Knowledge is slight concerning the pelagic movements of the New Zealand
Diving Petrels between January and March, when they are far from the coast.
During this period the moult is carried out.
On the breeding grounds the birds come to their nests only after dark, hurt-
ling in without preliminary circling, and landing heavily, each close to its own
burrow. Courtship and pairing, according to Falla, take place outside the
burrows. At this period the petrels are very noisy, making both mewing and
cooing notes. After the egg 1s laid, the vocal phase subsides more or less.
During courtship the adults probably refrain from eating, for Falla found
little or nothing in the stomachs of such birds. When they are feeding young,
their alimentary tracts are likely to be filled with a fine paste composed of
various oceanic crustaceans. Divers are the only petrels in which Falla has
never found remains of cephalopods.
With reference to the depths to which these birds can dive, Layard (1862,
99) states that among the Poor Knights Islands, in September, his steamer
passed through large flocks of Diving Petrels, and that some of the birds plunged
right beneath the ship, emerged close under the counter on the opposite side,
and then rose and flew off like quail.
TRISTAN DIVING PETREL
Pelecanoides urinatrix dacunhae
Pelecanoides dacunhae Nicoll, 1906, Bull. Brit. Orn. Club, 16, p. 103 (shore waters of the island of Tristan
da Cunha).
Names: Flying-penguin is the local name of this petrel at Tristan da Cunha. In the literature
it has often been listed under the specific names wrinatrix and exsul.
Characters: Apparently most closely allied to P. u. berard, but perhaps with generally smaller
dimensions. Feathers of cheeks, sides of neck, and jugulum with conspicuous, dark brownish
shafts in the two specimens examined.
2 females: length (skins), 202-204 (203); wing, 108-113 (110.5); tail, 36.5-37 (36.7); exposed
culmen, 15.5-16.5 (16); width of bill, 7; depth of bill, 5-5.5 (5.2); tarsus, 24; middle toe and claw,
29-31 (30) mm.
Egg: White; 38 x 29, 36.5 x 30 mm. (Mathews, 1932, 38); one from Gough Island measured
40 x 29.5 mm.
Distribution: The Tristan da Cunha group and adjacent waters. A diving petrel, provisionally
treated as of the same race, also inhabits Gough Island.
TRISTAN DIVING PETREL 791
The status of this Diving Petrel, as regards its place in the family, is very
uncertain. Beyond the fact that a member of the species wrinatrix lives at Gough
Island and the Tristan group, and that the bird has received the subspecific
name dacunhae, we know very little. I have been able to find only two speci-
mens, both in the British Museum. Murphy and Harper (1921, 541) give a
detailed description of the type but, since the bird has very worn and faded
plumage, it is of almost no value for comparison with examples of other
races. Satisfactory fixation of the identity of this form will have to await
further collecting.
Most of our information concerning this petrel is contained in the following
account by Nicoll (1909, 67) of observations made in January, 1906. It should
be remembered, however, that he underestimates in his comparison the flight
powers of Pelecanoides magellanicus.
The most interesting birds which we saw were some diving petrels, which proved to belong
to a species not hitherto recorded from Tristan da Cunha. Superficially these petrels resemble the
diving petrel of the Straits of Magellan, but they are somewhat smaller and have a much greater
power of flight. On several occasions I saw them rise off the water and fly away out of sight,
whereas those found in the Magellan Straits drop into the water after a flight of about fifty to one
hundred yards. The Tristan da Cunha diving petrels are constantly exposed to rough weather and
breaking waves, and in consequence have to take wing continually to avoid being drowned, and
this fact may account for their greater powers of flight.
They were met with soon after we left the yacht, and became more numerous as we approached
the land. Half a mile from the shore they were on allesides of us, and appeared continually close
to the boat, when instead of diving they at once took to flight, and passed away at a great speed.
A Diving Petrel taken by the ‘Scotia’ expedition off Gough Island, which is
about 400 kilometers south of the Tristan group, was doubtless this form.
Wilkins (1923, 503) observed great numbers in the waters around Gough Island
between May 28 and June1, during the ‘Quest’ expedition. He statesthat the bird
is well known to the Tristan folk, but that they have apparently never found its
egg. However, Mathews (1932, 38) lists an egg collected at Nightingale Island
in November, 1929, and quotes a somewhat hazy statement that the birds are
abundant there.
In books by Mrs. Barrows (1910) and Mrs. Rogers (1928), wives of Tristan
missionaries, no mention is made of Diving Petrels among birds observed during
long residence at the main island. The fact that Tristan da Cunha is overrun
with rats (cf. p. 481) suggests the probability that the burrowing Pelecanoides
have been forced to confine their nesting to neighboring and uninhabited islands
of the group.
COPPINGER’S DIVING PETREL
Pelecanoides urinatrix coppingeri
Pelecanoides urinatrix coppingert Mathews, 1912, Birds Australia, 2, p. 238 (Cockle Cove, Pilot Island, Trinidad
Channel, Chile, latitude 50° 05’ S.).
Names: The type of this supposed form was collected in October, 1879, and has several times
been referred co in the literature under the name wrinatrix.
Characters: Status uncertain; apparently nearest to P. w. berard, but perhaps averaging smaller;
scarcely any trace of mottling across the jugulum.
92 OCEANIC BIRDS OF SOUTH AMERICA
1 male (2): length (skin), 193; wing, 116; tail, 41; exposed culmen, 16; width of bill, 7; depth
of bill, 6; tarsus, 25; middle toe and claw, 31 mm.
2 females: length (skins), 165-206 (185.5); wing, 106-111 (108.5); tail, 36-38 (37); exposed
culmen, 15.5-16 (15.7); width of bill, 7; depth of bill, 5.5; tarsus, 25-25.5 (25.2); middle toe and
claw, 31 mm.
Distribution: Known only from the coast and inland channels of southern Chile, between
latitudes 47° and 50° S.
If the status of the Tristan Diving Petrel is unsatisfactory, that of the form
of urinatrix known to inhabit waters of the southern Chilean archipelago, to
northward of the western entrance of the Strait of Magellan, is much more so.
The bird was originally described with an incorrect type locality, and it has
never been properly diagnosed. The characters and measurements given above
are too deficient to be of much practical use. Nevertheless, I have given the
race a separate heading in order to attach at least a provisional handle to the
following brief account of what is known.
I have seen but five specimens, of which four are in the British Museum and
one in the Berlin Museum. One is from an unrecorded locality in southern
Chile; the others are from Trinidad Channel, from Messier Channel which is to
northward and inland, east of Wellington Island, and from 30 kilometers at sea,
off Tres Montes, in latitude 47° S., longitude 76° W. The last data refer to a
single female captured by Paessler during October, and recorded by Stresemann
(1922, 130).
Murphy and Harper (1921, 544) quote observations from Beck's notebook on
Diving Petrels seen in early July, 1914, between Anctd and Puerto Montt, Gulf
of Chacao, Chile, and later in the Pacific off Guamblin Island and off the Gulf
of Pefias. These notes were thought to refer to the present race, but it is now
known that all of the localities named lie within the range of Pelecanoides
magellant.
All that we can positively say is that a representative of the species wrinatrix
is found in southern Chile, in waters also occupied by the Magellanic Diving
Petrel. The nest and eggs of the former have not been discovered, and observa-
tions certainly referring to it are few. As to what the bird really is, I should say
that there are three possibilities, as follows:
1. It may be a resident subspecies of urinatrix, the distinguishing character-
istics of which are not yet accurately known because of scarcity of specimens.
2. It is possible that the Falkland race of the Diving Petrel nests also on
the continental coast, as Paessler (1922, 441) has suggested, and that the bird
here called coppingert is nothing else than berard, the range of which extends
through the Strait of Magellan and northward along the channels of the
Pacific coast.
3. It may prove that no race of wrinatrix nests in southern Chile, and that
the few specimens known are nothing else than surviving waifs which have been
blown by westerly gales against the continental shores from some remote
region in the South Pacific. Buller (1873, 313) and many other observers have
testified to similar casualties, on a large scale, in other parts of the world.
THE PELECANIFORMES 793
THE PELECANIFORMES
The members of this order, unlike their distant (and yet nearest) relatives,
the petrels and penguins, include birds of rivers, lakes, and swamps, as well as
those of seacoasts and the open ocean. Thus, in a world-wide sense, the snake-
birds (Anhinga), many cormorants, and certain pelicans belong partly to the
interior regions of continents and large islands. With a single exception, how-
ever (viz. Phalacrocorax olivaceus), all of the South American cormorants and
pelicans are at least primarily marine.
Among the forms of the five Pelecaniform families falling within the scope
of this book, the pelicans are the most closely ‘‘tied to the land.’’ Then follow,
in a sequence leading toward pelagic proclivities, cormorants, man-o’-war birds,
boobies, and tropic-birds. Cormorants and man-o’-war birds in some instances
give a specious appearance of being wide-ranging ocean fowl, the former because
they have established themselves at remote islands in high southern latitudes,
and the man-o'-war birds because in similar manner they have peopled the pan-
tropical islands and archipelagoes. All forms of both these groups are, never-
theless, extraordinarily sedentary. In the southern hemisphere, cormorants do
not even make regular migrations of any considerable length. The man-o'-war
birds have found their way fortuitously to innumerable small and isolated
oceanic islands, but their high percentage of endemism either as subspecies or as
species, and the orderly and logical distribution of such a species as Fregata
magnificens with reference to the trade-wind belts, show that these supreme
masters of flight tend to cling remarkably to the neighborhood of their breeding
stations. Furthermore, despite popular opinion to the contrary, man-o’-war
birds are rarely seen far from land.
The evolutionary history of the Pelecaniformes is a long one, though recon-
structed only from scanty records. Fossils ascribed to the families of tropic-birds
and pelicans have been found in Lower Eocene strata. The genus Pelecanus, as
well as birds closely akin to modern boobies and cormorants, are known as
fossils from at least as far back as the Oligocene. In this connection the com-
ments of Wetmore are illuminating. This author is of the opinion that a meta-
tarsus of Phalacrocorax auritus from the Pleistocene of Idaho is referable to the
identical subspecies (a/bociliatus) that inhabits the inland lakes of the same
region at the present day. He then continues:
While it is commonly recognized that numerous fossils indistinguishable from living species
and therefore identified as representing modern birds occur in Pleistocene deposits, it may at first
glance seem dubious or even impossible to carry this same procedure back into the Pliocene. The
writer has in recent years expressed the belief that our modern avifauna, in so far as its various
species are concerned, has had its period of origin and evolution in the Tertiary period, with such
changes as have since occurred confined to the minor differences that characterize geographic races
or subspecies, these being expressed in color and in slight variations in size. As his work with the
avian life of the past proceeds, he has become more and more convinced of these facts. It is there-
fore only natural to suppose that representation of various modern species will be found in Pliocene
deposits as more remains of birds from such horizons are discovered. This may be expected espe-
cially among such groups as the cormorants, which appear to be of ancient and long stabilized
type (Wetmore, 1933, 7).
794 OCEANIG BIRDS OF SOUTH’ AMERICA
The tropic-birds are the most aberrant of the Pelecaniformes in structure and
consequently in habits. At the same time the skeletal morphology, particularly
of the skull, suggests that they are the most generalized representatives of the
order. Their superficial resemblances to terns, which extend even to spotted
eggs, will be referred to hereafter.
The other families have much in common with one another, despite wide
divergence. Contrasts which seem enormous disappear in some instances when
comparisons are made at stages preceding the astonishing effects of differential
growth. Thus Maynard (1889, 140) has pointed out the almost incredible
change which ontogeny brings about in the relative size of the paired limbs of
Fic. 67. Bills of Man-o’-war Bird, Cormorant, and
Booby.
Upper, Fregata magnificens 9; middle, Phalacrocorax
gaimardi &; lower, Sula variegata @. All three genera
show a ‘‘bill-tooth’’ on the cutting edge of the maxilla
near the end of the quadrato-jugal bar. This is obso-
lescent in man-o'-war bird and cormorant, but is
apparently functional in the booby owing to a certain
flexibility at the junction of maxilla and cranium.
The man-o’-war bird has also an accessory notch at
the distal end of the latericorn which, in the booby, is
functionally replaced by sharp serrations.
the man-o'-war bird. In a two-
day-old chick the legs and feet are
actually larger than the wings!
The gular sac, moreover, is at first
proportionately capacious, and in
this feature as well as other de-
tails of head and bill the nestling
Fregata bears an extraordinarily
marked resemblance to a pelican
at the same stage of growth.
Subtle resemblances of behavior
include the fact that fledgling
man-o'-war birds tend to hold
the tip of the bill close to the
breast, in precisely the pelican
manner. Such facts go far toward
justifying an old popular name of
the man-o’-war bird—''frigate
pelican."’ A similar close con-
cordance between the young of
boobies and cormorants might
readily be cited. Both build and
behavior, moreover, point toward
a definite, though much more dis-
tant, relationship of the Pelecani-
formes with the petrel-like birds.
To turn from likenesses with-
in the order to points of discrep-
ancy, we may note how genetic
variation has pre-adapted the va-
rious types of Pelecaniformes for
a wide variety of ecologic niches.
Their ‘‘adaptive radiation”’ 1s,
indeed, far more marked than
that of petrels except as regards
THE PELECANIFORMES 795
size range, and infinitely more so than that of the extant penguins. The man-
o'-war bird—all wings and practically no feet—has lost the function of swim-
ming or diving. The boobies and salt-water pelicans share the possession of a
cellular subcutaneous cushion which admirably fits them for plunging from
the air. The cormorants lack this protection, but possess even more efficient
swimming feet. They have become grebe-like in their feeding procedure.
Furthermore, their powers of flight, as correlated with the length and com-
parative rounding or attenuation of the outer wing quills, show a greater
latitude than we find among other families of the order; one cormorant has,
in fact, become wholly flightless.
The Pelecaniformes exhibit curious relations as to the size of the sexes, per-
mitting a classification which seems to harmonize with no other criteria. Thus
among the boobies and man-o'-war birds, females are decidedly larger than
males. Among the races of the American Brown Pelicans the reverse is true.
Males and females within the families of tropic-birds and cormorants are of
about the same bodily size, though the bills of male cormorants average longer
than those of their mates.
As in the case of petrel-like birds, all kinds of Pelecaniformes appear to aban-
don their young completely and forever when the latter reach the state of
fledglings. Plentiful observation, relating to many species, confirms the general
truth of this. I have, however, found certain evidence that under rare circum-
stances the reaction of pleading for food by young or adult birds may prove
a sufficient stimulus to evoke the appropriate response from other adults for a
prolonged or indefinite period. While a single instance of such testimony might
carry little weight, several to the same purpose acquire a cumulative force. I
append two examples of what might be termed successful and permanent in-
fantilism, as practiced by adult but incapacitated Pelecaniformes. They are all
the more interesting because Mitchell (1911, 425) has shown that fowl of this
order have excellent viability, and potential longevities ranging up to about
fifty years.
The first of the following instances refers to a Brown Booby observed in the
Pacific during the course of the United States Exploring Expedition. The
second is concerned with a man-o'-war bird at one of the Revilla Gigedo Islands.
The fact that both accounts are tinged with a too altruistic interpretation does
not affect their value.
While exploring Enderby’s Island, which is of coral formation, we found a full-plumaged bird
of this species, that is, one having a white breast, which indicated it was several years old; it was
at least a quarter of a mile from the shore; and on picking it up, we were surprised to find it had but
one wing, the other having been by some accident, taken off close to the body; the wound was per-
fectly healed, the bird in excellent health, and very fat!—It was fed by its comrades, which were
younger birds, as indicated by the brown plumage of their breasts, and they continued while we
were near, to display all the careful anxiety of parents (Peale, 1848, 273).
Ata considerable distance from the colony a bird was found that was unable to fly, and thinking
that it had been recently injured, and must necessarily starve, where food was not easily obtained
by even the best of flyers, I killed the cripple and made an examination of its injuries. One wing
was withered and useless,—evidently the bird had never enjoyed its use, though it was fat and its
796 OCEANIC BIRDS OF SOUTH AMERICA
stomach was well filled with flying fish. Those who know the feeding habits of Fregata need not
be told that all their food is obtained on the wing, and a bird deprived of the use of its wings would
speedily starve if not fed by its fellows. The precipitous sides of San Benedicte also made it im-
possible for a Man-o’-War Bird to gain the top of the island if deprived of its wings. So it was
quite evident that the pensioner had never left the island, but had been dependent on the bounty of
its fellows all of its life. From its excellent condition it was evident that even in that busy com-
munity of thousands some of them found time to feed the unfortunate (Anthony, 1898, 314).
THE TROPIC-BIRDS
FAMILY PHAETHONTIDAE
Although there can be no doubt about the place of the tropic-birds in the
order Pelecaniformes, they differ much in habitus from all their existing rela-
tives, and share many superficial characters with the terns. These include form
and size, the shape of the beak, the silky sheen of the plumage, the voice, and
aérial grace. Furthermore, tropic-birds hatch from the egg covered with down,
instead of being naked like young boobies, cormorants, and pelicans.
The distribution of the tropic-birds matches very closely the distribution of
surface water according to temperature. Since the eastern sides of the continents
are washed by poleward-flowing warm currents, while the western sides have
cool currents flowing in the direction of the equator, it follows that the tropical
oceanic areas tend to be highly restricted on western coasts and spread out
widely on eastern coasts. Details of this familiar condition are discussed in
Part I of this book. Correlated with it is the fact that the oceanic ranges of
tropic-birds within our region are more or less wedge-shaped, with the apex of
the area close to Africa in the Atlantic region and to Panama in the Pacific
region. In more westerly parts of these respective oceans the tropic-birds extend
north and south through much wider belts of latitude. In the western Atlantic,
for instance, the breeding range stretches from the neighborhood of the Abrolhos
Islets (latitude 18° S.) to Bermuda (latitude 32° N.), and the flight-range still
farther northward and southward. It is curious that South Trinidad, which
lies much nearer the equator than Bermuda, and only a few degrees farther
southward than St. Helena and the Abrolhos Islets, seems to have no resident
representatives of the family. Likewise, tropic-birds appear to be unknown
along the Brazilian coast to southward of Cape Frio.
The opie birds lack the pecten which is so conspicuous on the middle
claw of their relatives. A broadened flange, in the position of the pecten,
is conspicuous in P. aethereus, however, and I believe it to be a homologous
structure.
Phaéthon aethereus has been called the most ‘‘primitive’’ member of the family,
at least as regards plumage characters, because the adults of this species wear
the same barrings which among the others are confined to the first contour
plumage. Among all tropic-birds the moult is apparently post-nuptial and
complete, and the sexes approximate each other in size.
Worth (1935, 442) has recently made observations leading to the supposition
Lie TROPITC-BIRDS 797
that the long tail of tropic-birds has a tactile function during the aérial antics
of courting birds. He has watched pursuit-flight, at the culmination of which
one adult would take a position directly above another, and then bend the tail
downward so that the long plumes would touch the bird flying below.
SOUTH ATLANTIC RED-BILLED TROPIC-BIRD
Phaéthon aethereus aethereus
Phaéthon aethereus Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 134 (Ascension Island).
Names: Boatswain-bird, Marlin-spike; *‘Rabo de Gallo’’; ‘‘Rabijunco”’ is both a Spanish and
Portuguese name; ‘Rabo de Palha”’ is also recorded from Brazil.
Characters: A large tropic-bird with a white tail, and with the dorsal surface thickly marked
with dark gray, transverse vermiculations.
Adults (sexes alike): General color glistening white; a black band, proceeding from a crescentic
mark above the gape and in front of the eye, passes through the latter and more or less outlines the
white crown; the caudad completion of this band depends upon plumage wear, the feathers of the
crown being white-tipped but basally black and, as the tips wear away, the black line tends to
become continuous; back and sides of neck, mantle, back, rump, upper tail coverts, and most of the
proximal wing coverts, transversely barred with neutral gray, these vermiculations tending to
increase in width caudad; greater wing coverts blackish gray, broadly fringed with white; the five
outermost primaries have the outer web, and the part of the inner web adjoining the shaft, grayish
black, only the extreme tips of the feathers being sometimes though not always white; in some
instances the third from the outermost quill is partially, and the fourth and fifth are entirely,
margined on the outer web with white; the remaining primary quills have a dark gray median
stripe, extending within 2 to 3 centimeters of their tips; innermost secondaries and their coverts
gray, more or less margined with white, especially externally; long flank feathers mainly gray,
with white marginal blotches and terminations; outer tail feathers with dark shafts, except distally,
and with a few irregular grayish marks; long central tail quills white, the shafts basally blackish.
Iris brown; bill crimson; tarsus and proximal part of foot yellowish flesh color, with the plantar
surface gray. In the parti-colored condition of the feet, the tropic-birds resemble certain petrels.
Following are the dimensions of two South Atlantic specimens:
3 Tail Exposed Middle toe
Wing Tail plumes | culmen Tarsus | and claw
Mics ASCENSION | sos cet! 326 119 63.3 29 46.1 mm.
Sex 2, St. Helena ..... 317 110 612 62.5 30 46.8
Data on the youthful stages and eggs of this, the typical race of the species, are not available.
Distribution: Known from the islands of Ascension, St. Helena, and, according to Peters
(1931, 77), also from Fernando Noronha.
Only since a recent revision by Peters (1930, 261) has it been realized that
the resident Red-billed Tropic-bird of the equatorial and sub-tropical South
Atlantic islands is a very distinct bird from the more familiar middle Atlantic
race, the range of which extends from the Cape Verde Islands on the east to
the Galapagos on the west. Doubtless the numerous South Atlantic records,
including those from the Abrolhos Islets and other parts of the Brazilian coast,
pertain to the subspecies aethereus. In view of our present lack of knowledge
regarding the geographic boundary between the two races, however, I have
elected to discuss them in the succeeding biography, which deals with the
species as a whole.
798 OCEANIC BIRDS OF SOUTH AMERICA
CARIBBEAN RED-BILLED TROPIC-BIRD
Phaéthon aethereus mesonauta
Phaéthon aethereus mesonauta Peters, 1930, Occas. Pap. Boston Soc. Nat. Hist., 5, p. 261 (Swan Key, Almirante
Bay, Panama).
Names: The vernacular names and the synonymy are the same as those of the preceding race.
Characters: Differs from P. a. aethereus in that all the dark areas, including the transverse bars,
tend to be black instead of gray; the deep black greater primary coverts, moreover, are sometimes
slightly tipped, but never edged, with white. Furthermore, the subspecies mesonauta is apparently
of slightly smaller size, particularly in length of wing.
Flesh colors are as in the preceding race. A male captured off Tumbez, northern Peru, on January
16, 1925, has the throat and breast suffused with pink, a characteristic which comes out frequently
among the tropic-birds, and which has no taxonomic significance. This specimen agrees in dimen-
sions and markings with Galapagos birds.
Examples in worn plumage have more or less dark crowns and a very densely barred, nearly
black dorsal surface, because of the loss of the white terminations of the feathers. The change
shows equally among Cape Verde and Galapagos birds.
Measurements of 18 adults of both sexes from the West Indies, Panama, the Pacific coast of
Central America, the coast of Ecuador, and the Galapagos Islands are: wing, 293-317 (305); tail,
94-115 (105); central tail plumes, 428-658 (541); exposed culmen, 60-66 (63.2); tarsus, 26-29
(27.8); middle toe and claw, 41-48 (44.5) mm.
Among 15 males and 15 females from the Cape Verde Islands, the dimensions are as follows:
wing, 283-319 (298); tail, 94-118 (106.8); central tail plumes, 414-700 (561); exposed culmen,
59-69 (63.7); tarsus, 27-30 (28.8); middle toe and claw, 44-48 (46) mm.
Gifford lists the maximum tail-plume length among 36 Galapagos males as 790 mm., the average
being 658 mm. The wing-expanse of a Galapagos malein the American Museum is recorded as 109 cm.
Peters (1930, 261) has described also a third subspecies (P. a. limatus), stated to have a longer
and more slender bill (maximum 68 mm.) than either of the preceding races. The color of the bill
in dried skins is alleged, moreover, to be yellowish horn-color rather than red. Tower Island,
Galapagos, is the only known breeding station of this proposed race.
Among a series of American Museum specimens from Hood Island, Galapagos, is a yellow-
billed bird with a culmen 67 mm. in length. It seems improbable that two races could thus exist
side by side at a single island. Moreover, among 15 males from the Cape Verde Islands are two
examples with culmens 69 mm. long. Finally, one Cape Verde male has a central tail plume which
exceeds the length of the first lateral rectrix by 584 mm., a character which, by implication, Peters
holds to be peculiar to the subspecies Jimatus.
Under the circumstances, I am leaving the status of the Tower Island tropic-bird for future
investigation, and am treating all of the Galapagos representatives as identical with those of the
Caribbean and the sub-tropical North Atlantic.
The juvenal plumage of P. a. mesonauta resembles that of the adult, but the dark transverse
bars are broader, and there is more black on the crown, forming an occipital crescent. The central
tail quills are barely longer than the adjacent pair, and the bill is yellow. Younger nestlings are
clad in down which is short and white ventrally, and long, silky, and gray above. The bill is
cream-color and the feet at first entirely light, gradually turning blackish distally.
The single egg exhibits great variation in form as well as in the amount and distribution of the
purplish or chocolate pigment (Murphy, 1924, 254, fig. 9). Some examples are very finely mottled,
others coarsely blotched. A concentration of pigment at the larger end is common. Six Cape
Verde Island eggs, selected for variety, measure: 64 x 43, 62 x 45, 55 x 41, 56 x 43.5, 66 x 44,
59x 40 mm. Bent (1922, 188) reports that the average of 40 eggs from the American side of the
Atlantic was 56.4 x 41.7 mm., the three extremes measuring 63.2 x 46, 50.5 x 39.5, and 51.5
x 36.5 mm.
Distribution: The eastern tropical Pacific from the Galapagos Archipelago to the coasts of
Peru and Ecuador and northward to the Gulf of California; the Caribbean Sea, the Antilles, and
the tropical and sub-tropical North Atlantic Ocean eastward to the Cape Verde Islands.
CARIBBEAN RED-BILLED TROPIC-BIRD 799
After weeks off soundings, in tropical blue waters where birds are scarce,
the voyager may sometimes be electrified by hearing the shrill whistle of the
Boatswain-bird. Looking aloft, he may see one, or perhaps a pair, of the gleam-
ing, long-tailed creatures passing high in air on steadily and rapidly beating
wings. On such occasions, according to my own experience, the visitors are
likely to show a certain brief curiosity in the ship, and will turn off their course
in order to fly in an oval orbit around it once or twice before streaking away
like animate comets. They are well named after Phaéthon, the son of Apollo,
who hurtled from the far sky into the sea. I remember the July day long ago
when, at a point to eastward of Martinique but out of sight of land, I first saw
one of a pair of Red-billed Tropic-birds dive from the height of the ‘Daisy's’
masthead into the quiet, transparent water. For several seconds it remained
below and, after reappearing, shook a shower of pearls from its feathers, rested
at the surface with wings spread and raised, and tail plumes cocked up, and
finally leaped into the air as lightly as a tern.
Both this species and the White-tailed Tropic-bird are true ocean wanderers,
unlike the man-o'-war birds and boobies which as a rule remain within distances
of a few hours’ flight from their insular headquarters. The tropic-birds, on the
other hand, visit the most remote parts of the warmer seas during times of the
year between their breeding periods. They even penetrate into the very heart
of the barren Sargasso regions, and Bennett (1860, 89) records several during
the month of April in latitude 23° 17’ N., longitude 42° 50’ W., which is about
as far from the nearest land as it is possible to get in the sub-tropical Atlantic.
We may first consider the distribution of the Red-billed Tropic-bird on the
Pacific side of America, where it is confined mostly to the restricted zone of
tropical water between Ecuador and Mexico. The outposts in the breeding
range appear to be at the Galapagos and the Revilla Gigedo Islands, and it is
interesting that these two groups occupy corresponding positions with reference
to the analogous Humboldt and California currents. In northern Peru the Red-
billed Tropic-bird is one of the species regularly seen at times when the warm
countercurrent is advancing southward. The birds were not uncommon, for
example, to westward of the Gulf of Guayaquil and Point Parifias during the
extraordinarily active advance of El Nifio in the latter pait of January, 1925.
At other times, when oceanic conditions are normal, the tropic-birds come this
far southward only far offshore, beyond the belt of active upwelling and where
the surface waters remain permanently warm. It is no doubt by such an outside
route that the species has in rare instances wandered in across the Humboldt
Current to Callao (Philippi, 1902, 89; Paessler, 1913, 47), Taltal CHellmayr,
1932, 295), and even to Valparaiso (Albert, 1899, 233). Von Tschudi (1846,314)
has published a record of the breeding of the Red-billed Tropic-bird during the
month of February on the high island of Fronton, off Callao. He states that two
fledgling young were in the nest, and that they flew away when approached.
This, however, is evidently the result of a misidentification, not only because of
its zo6geographic improbability but more particularly because all tropic-birds
rear but one chick.
800 OCEANIC BIRDS OF SOUTH AMERICA
The southernmost nesting station on the Pacific coast with which I am
acquainted is La Plata Island, Ecuador. Near here I have seen examples in
September and February, and when I visited the island during the latter month
in 1925, the lighthouse keeper informed me that the tropic-birds bred on the
cliffs at the northern end. At Daphne Island of the Galapagos, according to
Beebe (1924, 264), the breeding season extends at least from April to November.
It is probably continuous thrcughout the year in this archipelago, for Gifford
(1913, 105) reports both eggs and young birds during February, April, Sep-
tember, and November. Moreover, at Pacific islands in the northern hemisphere,
such as the Revilla Gigedos, eggs and young in every stage of growth have been
found in April and May (McLeéllan, 1926, 287). Gifford states that Red-billed
Tropic-birds were logged by members of the expedition of the California
Academy of Sciences in the neighborhood of fourteen islands of the Galapagos
group throughout the year; they were found nesting at four of the smaller islands
but were seen in numbers only at Daphne, Hood, and Tower. At Daphne Island
Gifford saw birds wheeling about, without beating their wings, near holes on
the hillsides When they seemed ready to enter their respective niches, they
would flutter to check their flight, stand in the air for an instant as though about
to alight, but would then usually continue, not entering the nest until the ma-
neuver had been repeated several times. At this island, nests not in natural
rock-cavities were in short burrows which covered the surface from close to
sea level to a hundred meters above it. In homes without an egg two adults
would sometimes be found together, but adults engaged in incubation or brood-
ing were always alone. The long central tail feathers of the birds became broken
or badly worn from the cramped quarters of the nest-chamber, and the fact that
the quills of females obviously fared worse than those of their mates may
indicate that females habitually undertake the larger share of the labor of
incubation. Competition for nesting sites was exceedingly keen, and Gifford
found that new occupants almost immediately took possession of homes after
the first proprietors had been collected. At Hood Island he also took a tropic-
bird and its fresh egg from a site which had been occupied by a pair of Swallow-
tailed Gulls only five days earlier. At Pacific islands off the coast of Central
America the Red-billed Tropic-bird has been known to make secondhand use of
burrows of the Wedge-tailed Shearwater (Beck, 1904, 5).
On the Atlantic side of the continent, the species inhabits various islands of
the Caribbean and the Lesser Antilles. At Orquilla of the Hermanos group, *
Venezuela, the birds have been found nesting in unlined holes among the broken
rocks of steep slopes during the months of March and April (Cory, 1909, 226).
In such places they reveal their presence by loud outcries against the stumbling
steps of intruders among their stones (Lowe, 1911, 214). At the same time of
year, Taylor (1864, 172) reports them as breeding in great numbers among the
cliffs of volcanic ash at Martinique. On Valliceaux, near St. Vincent, Ober
(1880, 224) found many nesting on more or less open shelves of the cliff, sitting
so quietly when he approached that he mistook them for young birds. Unlike
its smaller Atlantic relative, the Red-billed species apparently does not range
CARIBBEAN RED-BILLED TROPIC-BIRD 801
to northward of the Antillean Arc, but to eastward in the same latitude it reaches
‘the Cape Verde Islands, where large colonies breed throughout the year at Razo
and the Rombos Islets (Correia, in Murphy, 1924, 256). Southward across the
equator it ranges to Fernando Noronha, where the Cleveland Museum Expedi-
tion recently collected specimens; to Ascension, where it nests in holes burrowed
through the accumulated guano of the main island as well as at the outlying
rock to which this and the lesser species of the genus Phaéthon have given the
name Boatswain-bird Islet; to St. Helena, where its habits are similar; and to
the Abrolhos Islets, off the coast of Espirito Santo, Brazil (Goeldi, 1894, 598),
from where I have examined two specimens collected on December 28, 1887. The
Abrolhos seem to represent the southernmost known breeding station in the
Atlantic for, curiously, no tropic-birds have yet been recorded from South
Trinidad, an island which would seem to be well adapted to their support and
which lies within the sub-tropical zonal limits of their breeding area. It is
possible that they have been merely overlooked at South Trinidad.
At St. Helena, which is close to the southern border of the range, the Red-
billed Tropic-birds are very abundant along the southeasterly coasts, these
being the most precipitous and the farthest from the haunts of man. According
to Meliss (1875, 97), the birds nest in niches of the cliffs as high as 500 meters
above the sea. In launching into flight from such places they simply drop from
the ledges, an important consideration with this species, for its terrestrial
progression is not at all like that of boobies but rather resembles the gait of
weak-legged petrels. Correia states that adults can neither walk nor stand up.
They rest with their breasts on the ground, and to cover the short distance
between the nest-chamber and the jumping-off place, they merely push along
on their bellies, spreading their wings as props and balancers.
At the Cape Verde Islands Correia found that the tropic-birds set forth to-
ward their feeding grounds at daybreak, returning from the first trip about
eight o'clock in the morning. They then fly toward their respective clefts or
cavities but, instead of alighting, they poise in the air with the feet and tail
trailing, and afterwards describe short circles only to swing back and poise
again, repeating the performance for an hour or more. This agrees precisely
with Gifford’s experience at the Galapagos. Meliss writes that at St. Helena a
second return from the sea takes place during the latter part of the afternoon.
Gifford describes the vocal expression of this species as a series of short, high,
rasping notes given in quick succession. Young birds taken from the nest have
a similar cry, and even chicks a day or so in age utter three or four notes of it
when handled. Gosse (1847, 430) reports that there are two distinct call-notes,
one being like that of a gull, and the other a chattering trill like the rattle of
the Belted Kingfisher. The latter note, of course, is the ‘‘boatswain's whistle”’
which has given the species its commonest name among sailors.
The food of the Red-billed Tropic-bird comprises both fish and squids.
Remains of either are likely to be disgorged by young or adults when they are
disturbed at the nest. Birds coming out of the ocean after a plunge sometimes
show the prey held crosswise in the beak during the instant before it is juggled
802 OCEANIC BIRDS OF SOUTH AMERICA
and swallowed. Food is not carried to young in the bill, but rather in the
gullet or crop, petrel-fashion.
The principal enemies of this species seem to be man and the cats he has
introduced. According to Correia, hundreds of the birds are annually salted and
dried for human consumption by the native fishermen of the Cape Verdes.
Gifford states that the tropic-birds are practically immune from the attacks of
man-o'-war birds, and that the only mischief he ever saw the latter attempt was
unsuccessful. At St. Helena semi-wild cats destroy the young in all nests that
they are capable of reaching, besides which tropic-birds were formerly shot
here in great numbers for the use of their plumes in the millinery trade. In this
connection it is interesting to note that the tail plumes of the West Indian
tropic-birds were formerly valued by the Caribs just as those of the Pacific
Red-tailed species were by Polynesians. Du Tertre (1662, 2, 276) writes that
the primitive savages of the French West Indies were accustomed to fix the
plumes in their hair, or to stick them through a hole in the septum of the nose.
WHITE-TAILED TROPIC-BIRD
Phaethon lepturus
Phaéton lepturus Daudin, 1802, Buffon Hist. Nat., edit. Didot, Quadr. 14, p. 319 (Mauritius).
The species is of wide distribution in the tropical Pacific and Indian oceans, as well as in the
Atlantic, but no form occurs in the eastern Pacific, and the races which come within our region
comprise only an equatorial Atlantic form, which has thus far been described with complete in-
adequacy, and the subspecies of the Antillean-Bermuda district. The former of these has been called
Leptophathon lepturus ascensionis Mathews, 1915, Birds Australia, 4, p. 311 (Ascension Island).
Breeds at Ascension, Fernando Noronha, and islands of the Gulf of Guinea.
The second was described as
Phaéthon catesbyi Brandt, 1840, Mém. Acad. Imp. Sci. St. Pétersb. (6), 5, p. 270 (Bermuda).
Breeds in Bermuda, the Bahamas, and locally in the Greater and Lesser Antilles.
Names: Boatswain-bird, Yellow-billed Tropic-bird, Long-tail, Marlin-spike. Spanish-
American names include ‘‘Caracolera,"’ ‘‘Rabi-junco,’’ and ‘‘Chirre de Altura.’’ Synonyms of the
specific name are americanus, flavirostris, candidus, and edwardsii.
Characters: Smallest species of the genus; the adult without crossbarring; black and white or,
rarely, black and pinkish or salmon color.
Adults, of the Atlantic equatorial form, Phaéthon lepturus ‘‘ascensionis,’ which has never been
satisfactorily distinguished from the typical or Indian Ocean race (sexes alike): General color
glossy white, not infrequently with a peach-colored suffusion which, among certain specimens, is
heightened to a deep salmon or even orange tint; a broad black stripe, proceeding from a crescentic
black mark above the gape and in front of the eye, passes through the latter, more or less outlining
the crown; as a result of wear this band sometimes practically meets around the rear of the pileum
through exposure of the concealed bases of the feathers on crown and nape, which are black as in
P. aethereus; a broad black band is formed on the wing by the black distal halves of the median
coverts, this stripe being continuous with a large black area formed by the scapulars and innermost
secondaries, all of which are at least centrally black, although they may have white margins
and white tips; four outermost primaries with the outer web, and the portion of the inner web
adjacent to the shaft, black to within 2 to 3 centimeters of their tips; the fifth has the black area
confined to the shaft and outer web, while the proximal primary quills have little more than
partially black shafts; outer secondaries white; long flank feathers broadly striped axially with
grayish black, and somewhat sprinkled with grayish toward their borders; shafts of wing and tail
WHITE-TAILED TROPIC-BIRD 803
quills white below, but black on their upper surfaces, except distally; tail composed of 12 feathers.
Iris brown; bill bright orange-red, inclining toward vermilion on the culmen (at least during the
breeding season); tarsus bluish; toes and webs black.
2 males, Fernando Noronha: wing, 267-274 (271); tail, 97.6-105.5 (101.5); exposed culmen, 49;
tarsus, 23; middle toe and claw, 35.3 mm.
7 females, Fernando Noronha: wing, 251-275 (265); tail, 87.4-113 (101.3); central tail plumes,
403-461 (433); exposed culmen, 44-49.7 (46.6); tarsus, 21.5-23 (22.2); middle toe and claw, 36.9-
37 (37) mm. ;
The wing-spreads of the males were 92 cm.; those of the females 86.4-89 (87.8) cm.
Immature birds have yellow bills; those in juvenal plumage have the dorsal surface barred with
transverse black vermiculations, similar to the wavy marks of Phaéthon aethereus, but coarser. These
vermiculations are lost mainly through wear, but it is possible that they are to a slight extent
renewed on the plumage which immediately succeeds the post-juvenal moult. Younger chicks are
clad in grayish white down, which is nearly pure white on the face, belly, and middle of back.
Birds of the Bermuda-West Indian subspecies, Phaéthon lepturus catesbyi, differ from the equatorial
and South Atlantic representatives in that the black area on the outermost primary extends close
to the tip; on the second and fourth from the outermost it practically reaches the tip; while the
third from the outermost quill is entirely black or no more than very narrowly tipped with white.
There is also much more black on the fifth from the outermost quill. All of these black markings
of the remiges are remarkably conspicuous when the birds are in flight.
The Bermuda race may also be slightly larger than the equatorial race. Figures covering both
sexes, and recorded by Gross and by Plath, are: wing-expanse, 885-965; wing, 271-281; bill,
49-54 mm.; weight, 367-465 grams, the average of six birds being 407 grams.
According to Plath, the plumage of full maturity and the bright orange-red bill are not attained
until the third year. The roseate tinge on the satiny white plumage of neck and breast of sporadic
examples is mentioned by Gross.
The single egg is variable in shape and markings, with a pinkish white ground color more or
less thickly concealed by brown, purplish, and chocolate specklings, cloudings, and blotches in
endless variety. The shell is extraordinarily tough and somewhat elastic. Eight measured by
Gross had extreme lengths of 49-58 and breadths of 36-41 mm. They weighed from 35.2-45 grams,
with an average of 40.4 grams. The weight decreases slightly during incubation, as water is lost.
Extreme measurements among 40 eggs of this race, as recorded by Bent (1922, 183), were 60 x 40,
56 x 41, 50 x 37.5, and 51 x 36.5 mm.
Distribution: The difference in the flight-ranges of the two races considered above has not been
worked out in detail. The range of the American representatives of the species /epturus, as a whole,
appears to be entirely Atlantic, and to extend from the edge of the Sargasso Sea off eastern North
America southward through the Antillean-Caribbean region to Fernando Noronha, and eastward
across the tropical Atlantic to Ascension and the Gulf of Guinea. The two races are jointly dis-
cussed in the following biography.
Within our region the White-tailed Tropic-bird is confined to the Atlantic,
in which ocean it breeds at Bermuda, the Bahamas, many islands of the Antilles,
and at Fernando Noronha and Ascension. Throughout the northerly part of
this breeding range, the tropic-birds are by no means permanent residents, but
they make an annual migration to Bermuda where they appear in February or
March to remain until October or, casually, into November. A certa#in migra-
tory movement seems also to be apparent in the Bahamas and among some of
the West Indian islands, but at the Lesser Antilles the species is resident
throughout the year.
Neither are the movements at sea confined by any means to migrations for
reproduction. After the nesting season has passed, indeed, the White-tailed
Tropic-birds wander far and wide, and reach latitudes much nearer the pole
804 OCEANIC BIRDS OF SOUTH AMERICA
than any part of their breeding range. Until recently, exact pelagic records
from points between the equatorial Atlantic and the coast of Nova Scotia were
suggestive but rare (Reid, 1884, 262; Lowe, 1911, 215). The work of Jespersen
(1930, 28) during the cruise of the ‘Dana’ has shown, however, that this species
on its wanderings is distinctly a denizen of the Sargasso Sea, and that it occurs
regularly during the northern-hemisphere autumn as far northward as latitude
40° N. It is in accordance with well-established oceanographic principles,
moreover, that the pelagic records of this tropic-bird should be much more
numerous and widespread in the warmer western half of the North Atlantic
than they are in the eastern:half. Jespersen states that it was exceptional in
his experience to find this bird anywhere to eastward of longitude 30° W., and
that, while encountered everywhere within the Sargasso Sea, it was most num-
erous in the western part of it.
Jespersen continues that on the high sea the White-tailed Tropic-bird is
usually seen alone, and never in large companies. Twice he has encountered
three or four together, but this was only within a few hours’ flight of Bermuda.
During 112 days of observation, at distances of not less than about 100 kilo-
meters from the nearest land, he observed three or four together on only two
days, two together on 28 days, and only single birds during the remainder of
nearly three-fourths of the days of record. On a very few occasions he saw
tropic-birds settle on the water, and this exclusively in fine weather when the
sea was smooth. Such swimmers always held their elongated tail feathers at
an upward angle, as if to keep them dry. Flying birds, according to Jespersen’s
experience, show more or less short-lived curiosity regarding a ship, and he
once observed one that for some time hovered above the truck at the main
masthead and kept pecking at its vane. Again, during a heavy thundersquall
in which waterspouts followed a downpour of rain, a tropic-bird attempted
to alight upon the vessel.
At one of the South American breeding stations, namely the Brazilian island
of Fernando Noronha, I became acquainted with the White-tailed Tropic-birds
on October 16, 1912. At this time they were nesting in niches of the cliffs
above the beach, as they apparently do here throughout the year. Three birds,
frightened from their inaccessible nest-chambers and shot, all proved to be
females. Two of them were of the normal satiny white coloration, but the third
was of a pale pink or pinkish salmon hue, slightly more orange on the dorsal
surface. This condition represents a phase, the meaning of which is not under-
stood, but which crops out among a small proportion of the birds in various
parts of the world. A second famous South Atlantic breeding station is at
Boatswain-bird Islet, Ascension, where the White-tailed Tropic-bird nests in
close proximity with its larger relative, the Red-billed species, as is true also
at Fernando Noronha.
The principal biographic studies on this species have been made at Bermuda
by Gross (1912, 49) and Plath (1914, 552), from whose valuable reports most
of the following data have been drawn.
The sense of orientation of the White-tailed Tropic-bird is shown not only
WHITE-TAILED, TROPIC-BIRD 805
by its seasonal return to Bermuda, which is more than 1000 kilometers from
the nearest land, but also by the fact that the same individual birds come back
year after year to the same nesting sites, as has been determined through band-
ing experiments. In 1901 it was estimated that 2000 pairs of the “‘Long-tails’’
nested at Bermuda, and it seems probable that this population approximately
holds its own year after year. After arriving at the breeding grounds the adults
are not shy, nor do they appear to resent close inspection by human beings,
except during the period of egg-hatching which transiently conditions them
to a state of ferocious antagonism.
The foraging flights of the Long-tails take them a relatively great distance
from land, certainly far out of sight of the islands and doubtless regularly as
far as 100 kilometers or even more. Reid (1884, 263) reports seeing a pair resting
on the water about 150 kilometers to eastward of Bermuda. The adults are
most active in early morning, first leaving their cliffs about five o'clock. By
half-past eight there is a considerable decrease in activity, which practically
ceases by the middle of the forenoon. Shortly before sunset there is another
period of movement, though this is less pronounced than that of the morning.
The diurnal rhythm is described by Scott (1891, 249) as being exactly similar
at Jamaica. At the latter island the White-tailed Tropic-birds are commonest
during the winter season, that is from December to March, which may indicate
a swelling of the local population through migration from more northerly
breeding stations such as Bermuda.
The Long-tails are not strictly gregarious birds, the concentration of their
nests being due rather to the scarcity of suitable sites. The fact that they are
nearly helpless on a level surface, and there capable of progressing only by
crawling and bouncing along on flattened tarsi, makes them of necessity cliff-
dwellers. At Bermuda the nests are either on ledges or in small caverns. If the
former, they are often at the base of herbage which protects them from the
intense heat and light of the sun. Some are situated on ledges so low as to be
in danger of being drenched by waves; others are in sites up to 30 or 40 meters
higher. Pairing takes place at the nest, and Gross believes that two broods are
annually reared by each couple.
The single egg has a strong and somewhat elastic shell, well adapted to
resist the rough stone upon which it is laid without benefit of a soft flooring.
Batches of fresh eggs appear at Bermuda by April 10, and again at the end of
June (Reid, 1884, 263), which supports the hypothesis of successive broods. In
the white limestone cliffs of Jamaica, Scott has found adults covering eggs in
the honeycombed cells on February 27. In larger caves at the same place eggs
were found between boulders on a sandy floor. Here, too, a chick estimated
to be more than a week old was found on March 15, which would place the
date of egg-laying in early February. It is highly probable that at such sub-
equatorial islands as Ascension and Fernando Noronha the nesting season is
nearly or quite continuous throughout the year.
Both sexes incubate, but an adult has also been observed feeding its mate
while the latter remained on the egg. It is not unlikely that the female is the
806 OCEANIC BIRDS OF SOUTH AMERICA
more broody of the two. When parents relieve each other at the nest, they
indulge in a brief affectionate ceremony and mingle their caresses with sounds
which resemble the “‘flicker’’ call of the North Ametican woodpecker of that
name (Colaptes). Gross states that the period of incubation is not less than
28 days, and Plath determined that an egg placed in an incubator took exactly
that length of time to hatch. The process of coming out of the shell is evidently
a slow one, for within a pipped egg the calls of a chick have been heard for 42
hours before it finally emerged. The weight of a newly hatched chick, which
has not yet received food, is little more than half the weight of an egg. The
eyes of the nestling are closed for a day or two, but any stimulus excites it to
extend its neck and open its beak, in anticipation of a meal.
For the first ten or fifteen days the food supplied the offspring consists of
pteropods and other soft-bodied marine animals, but between the fifteenth and
thirtieth days more than 90 per cent of the sustenance is made up of squids, the
remainder being chiefly fish. Since the young regurgitate upon slight provoca-
tion, their food can be readily analyzed. The quantity ejected sometimes equals
one-fifth the weight of the bird. Gross infers that most of the squid are cap-
tured during the early morning hours, and far out at sea. This is confirmed by
the observations of Jespersen, who analyzed the stomach contents of eight
adults shot out of sight of land. These included nothing other than remains of
cephalopods, the largest of which measured 12 centimeters in length. Most
species of such organisms avoid the uppermost layers of the ocean during hours
of strong light. They can best be captured early in the day, when the tropic-
birds may be seen diving frequently from heights of 15 to 20 meters, the birds
first hovering like Kestrels and then falling with wings folded. Usually they
twist or spiral on the way down, a characteristic which is also very pronounced
in the plunging of the Brown Pelican.
During the early period of the young tropic-bird’s life it is fed frequently,
but after three weeks or thereabouts the adults carry squids to the nest cavity
two or three times shortly after six o’clock in the morning, and then disappear,
presumably to take care of their own needs, for a period of 24 hours. The lonely
youngsters sleep much of the time but respond attentively to every sound and,
of course, come to life vigorously when they hear the characteristic clicking
call of a returning parent. In response to this sound the chick utters a series of
guttural chirps, and braces itself on legs and tail in anticipation of the breakfast,
which is delivered with much gulping and wriggling.
About 62 days are spent in the nest after hatching, making a total of 3 months
between the time the egg is laid and the date when the fledgling takes flight.
Feathering is completed by the 40th day, though the down still clings to the
head and rump. Like young shearwaters the chicks are unable to fly strongly
at the time of leaving the nest. They usually leap off the ledges, glide to the
water, and then make their way to sea by swimming. They doubtless must
depend for some time upon their stored fat, until they have gained strength to
fly and to fish for themselves. Gross suggests that possibly the parents feed them
on the ocean, but it would be well worth inquiring as to whether they are not
WHITE-TAILED TROPIC-BIRD 807
completely abandoned by the adults before they leave the nest, in which case
increasing hunger would supply the necessary pulling of the trigger for bringing
about this reaction.
Aside from the harsh scream, like an exaggerated tern voice, which the
White-tailed Tropic-bird often utters in flight or as a protest while on the nest,
it has a number of softer calls. One of them Plath describes as tik-et, tik-et, tik-et,
a chorus of such notes sounding like a creaking pulley. The Flicker note, heard
when adults relieve each other at the nest, has been mentioned above, as has
also the clicking sound uttered when parent approaches chick with food.
Aside from the prey already referred to, Gross has noted two species of flying
fish, and fragments of sea-urchins and crabs, among material regurgitated by
these birds. Penrose (1879, 277) states that crabs of some sort are a staple food
at Ascension.
At Bermuda the principal enemy of the White-tailed Tropic-bird is the roof
rat (Rattus rattus, subspecies).
THE PELICANS
FAMILY PELECANIDAE
The pelicans are a widely distributed family of chiefly continental birds, the
Galapagos being the most isolated islands that they have anywhere reached
except for the accidental occurrence of one species in New Zealand. Many
pelicans are primarily birds of fresh water, but all of those occurring within
the field of this book are distinctly sea fowl, although the tropical representative
is by no means averse to entering the lower courses of rivers.
The South American pelicans are all ‘‘Brown Pelicans," referable to the sub-
genus Leptopelicanus of Reichenbach. They are of two groups, of which one is
the Peruvian or Chilean Pelican, formerly given specific rank but now regarded
as a subspecies of the typical West Indian form. At any rate, it is a distinctive
bird because of its large size and because of its well-defined endemic range.
As regards the forms of the Brown Pelican occurring in North and Central
America, the West Indies, and the northerly tropical coasts of South America, I
have not yet been able to come to any final taxonomic conclusion. Peters (193),
81) has recognized three races, of which one (occidentalis) is confined to the
Antilles, a second (carolinensis) nests along the Atlantic and Gulf coasts of the
southeastern United States, and a third (californicus) is said to range along the
Pacific coast from British Columbia southward to Ecuador and the Galapagos
Archipelago. This division of the species, particularly with reference to the
last race, seems to me quite unsatisfactory both in relation to the specimens I
have examined and to geographic likelihood. Since Brown Pelicans constantly
cross the Isthmus of Panama via natural waterways, as well as through the
man-made Canal, it would be hard to believe that the subspecies of the Caribbean
and of the Pearl Islands and adjacent parts of the Pacific coast are not one and
the same. Swarth (1931, 37) distinguishes between the California and Gala-
808 OCEANIC BIRDS OF SOUTH AMERICA
pagos pelicans, but he specifically states that Galapagos and Caribbean birds
are indistinguishable.
The Brown Pelicans in any population vary to a highly puzzling degree and,
until a study based upon more ample material than I have seen has made possible
fully demonstrable conclusions, I can only suggest the following probabilities
which are based upon the limited data at my disposal.
1. Pelecanus occidentalis occidentalis Linnaeus
Type locality, Jamaica; material examined, 6 males and 7 females from
Jamaica, Porto Rico, and St. Thomas.
These birds represent a well-marked race, strikingly smaller than the pelicans
of the continental coast of North America. The range includes at least part of
both the Greater and Lesser Antilles, though Dr. Wetmore informs me by letter
that a Cuban specimen he has received belongs to the race of the southeastern
United States, not to the smaller West Indian form. Peters includes within the
subspecies occidentalis the native pelican of St. Vincent, and Rothschild and
Hartert (1899, 177.) remark significantly that pelicans collected at Aruba Island
are smaller than any they have seen from the west coast of America.
From such data it would be natural to conclude that all the pelicans inhabit-
ing the Caribbean islands off the coast of Venezuela, as well as those which range
southeastward beyond Trinidad to Guiana, and casually as far as the Amazon,
are likewise of the Antillean race. It so happens, however, that a male from
Cumana, Venezuela, agrees definitely with Florida, rather than with Jamaica,
birds. This indicates that further collecting and systematic study is required,
particularly since the pelicans of Panama, Colombia, and Ecuador are relatively
large birds which agree with the pelicans of the southeastern United States,
rather than with those of the Antillean Arc. The existence of a small West
Indian pelican, the distribution of which remains to be defined, at least empha-
sizes the strictly littoral nature of the group as a whole.
2. Pelecanus occidentalis carolinensis Gmelin
Type locality, Charleston, South Carolina; material examined, 5 males from
Florida and Texas, 1 from Venezuela, 7 from Ecuador, and 1 from Talara, Peru;
4 females from Florida and Texas, 1 from western Panama, 1 from Punta Piedra,
Costa Rica, 2 from Ecuador, and 2 from Talara, Peru.
All of these are, in so far as I can judge, racially indistinguishable in appear-
ance and measurements, indicating for the subspecies carolinensis a distribution
along both continental coasts of the Middle American region from the southern
United States around the peripheries of the Gulf of Mexico and the Caribbean
to northern South America; and on the Pacific coast throughout the zone of
warm ocean water from southern Mexico to northern Peru.
3. Pelecanus occidentalis californicus Ridgway
Type locality, La Paz, Lower California; material examined, 5 males and
4 females from the coasts of California and Lower California. In conjunction
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810 OCEANIC BIRDS OF SOUTH AMERICA
with these I have also made use of the measurements and descriptions of Gifford
(1913, 118).
From the data at hand I judge that this race is confined to the semi-arid
western coast which is bathed by the relatively cool waters of the California
Current, and that it does not extend to southward of southern Mexico. It is,
in short, probably an analogue of Pelecanus occidentalis thagus, the bird of the
corresponding cool-current region of western South America.
4. Pelecanus occidentalis, subspecies?
Galapagos Archipelago; material examined, 1 male and 1 female from the
Galapagos.
Judging from this inadequate material, and from the published data of the
authors already cited, I conclude that the affinities of the Galapagos Pelican
are with the tropical continental birds and not with those of the California
coast. As indicated by the figures of Gifford, the Galapagos birds are smaller
than those from California. At the same time they seem to average distinctly
larger than specimens of the race carolinensis. Further study may show that the
Galapagos Pelican is worthy of subspecific recognition, even though a number
of competent systematists have thus far failed in efforts to distinguish it. The
very fact that its alleged affinities have been bandied back and forth between
the California race and the race of the Atlantic coast, shows that the last word
on this subject has not been said.
On page 809 is a summary of measurements based upon the 51 specimens of
American Brown Pelicans, representing four or perhaps five races, which I have
personally measured.
BROWN PELICAN
Pelecanus occidentalis
Pelecanus occidentalis Linnaeus, 1766, Syst. Nat., edit. 12, 1, p. 215 (Jamaica).
Pelecanus carolinensis Gmelin, 1789, Syst. Nat. 1, pt. 2, p. 571 (Charleston, South Carolina).
Pelecanus occidentalis, subspecies (Galapagos Islands).
In view of the foregoing discussion, and the fact that all the pelicans I have seen from Pacific
coast localities between Costa Rica and Point Parifias, Peru, agree well with examples from Florida
and the Gulf of Mexico, I am tentatively listing the Brown Pelican of tropical South America as
Pelecanus occidentalis carolinensis, and am treating the Galapagos form separately at the end of the
following biography.
Names: “‘Alcatraz’’ or ‘‘Pelicano’’ in most Spanish countries; ‘‘Pelecano’’ in Brazil; ‘‘Grand
Gossier’’ in French Guiana. Synonyms of the specific and subspecific names of the Brown Pelican
include fuscus, californicus, albicollis, and relictus.
Adults in breeding plumage (sexes alike): Back of head, and feathers bordering the gular pouch,
white; remainder of head, including the short occipital crest, straw-yellow; neck rich velvety
brown, the hue varying, according to the state of wear and fading, between seal-brown or nearly
black and light reddish chestnut; the feathers on the nape show more or less of a mane or crest;
dorsal body plumage pale ashy or silvery gray, the feathers of the back, rump, lesser and median
wing coverts, and scapulars edged with blackish brown, producing a striped appearance; primaries
black, with the proximal three-quarters of the shaft white; secondaries and rectrices mostly ashy,
becoming brownish and dingy with wear; ventral surface smoky brown, the flanks and sides of
breast with silvery white shaft-stripes. Iris yellowish; naked skin around eye blue; bill grayish,
BROWN PELICAN 811
tinged with brown and spotted irregularly with red, the distal end blackish, more extensively on
the lower mandible; pouch dull greenish brown or olive-brown; tarsi and feet black.
The whitish scale which forms on the bill of pelicans, sometimes covering a considerable part
of it, seems to be a dermal excretion. It is not calcareous, as I have found by testing it with acid.
In the so-called winter or non-breeding plumage, which is acquired by a post-nuptial moult
but which may be found at any time of year, all the feathered parts of the head and neck are white
except for a straw-yellow tinge on the head and at the base of the fore neck. Such examples en-
countered during the breeding season may be immature.
For general measurements, see the foregoing table. The wing-spread of a specimen taken at
Point Santa Elena, Ecuador, was 220 cm.
In young birds the head and neck are brownish gray, mottled by paler feather tips; the back and
mantle are dull brown, the feathers tipped with pale fulvous; the lower parts are white, tinged
laterally and posteriorly with brownish gray. Downy young are white in all stages.
Eggs usually number two or three in a set, the latter number being more common. They are
very hard and thick-shelled, with a chalky and granular white surface. Measurements of 46
examples average 73 x 46.5 mm., the four extremes having dimensions of 83 x 49, 81.5 x 54,
68 x 47, and 70.5 x 45 mm. (Bent, 1922, 297).
Distribution: The range of the Brown Pelican of tropical South America, as here interpreted,
extends from northernmost Peru to the Pacific coast of Costa Rica, and on the Atlantic side from
the southeastern United States along the shores of the Gulf of Mexico, Central and South America,
to Trinidad and British Guiana, and casually farther southeastward to the River Amazon. South
American breeding stations are chiefly at suitable islands along these coasts. In the Pacific there
are colonies on Santa Clara Island in the Gulf of Guayaquil, at the Pearl Islands in the Bay of
Panama, etc.; on the Atlantic side there are colonies at a number of the islands off the coast of
Venezuela, such as Tortuga, islets off Aruba, etc. The pelicans of the Galapagos, which are at
least closely related to the tropical South American birds, are confined to the Archipelago.
In view of the taxonomic uncertainties detailed above, I am here combining
the notes on Brown Pelicans from all parts of the tropical South American
region, disregarding the possibility that more than one subspecific unit may be
involved. For data on behavior, and other biological information, I have
drawn upon literature referring to pelican colonies at points more or less distant
from any part of the continental coast of South America, such as islands off
British Honduras, the West Indies, and Florida.
In Part I of this book I have discussed at length the oceanic conditions which
prevent pelicans from extending their normal range much to southeastward
of the point at which the southern end of the Antillean Arc approaches the main-
land coast. In the northern autumn pelicans sometimes flock by hundreds
around Barbados, as though they had come from somewhere on a definite mi-
gration (Feilden, 1889, 501). At Trinidad they are present throughout the year,
but are apparently not known to breed. Beyond this region, straggling birds
cross the Gulf of Paria and enter the mouths of the Orinoco (Beebe, 1909, 79).
Furthermore, at least a few pelicans make their way up the increasingly muddy
Ocean current that sweeps along the coast of Guiana. Schomburgk (1848, 2, 456)
reports them as flying in every evening over the mudbanks of the shore, to
spend the night in the trees of the neighboring forest. Chubb (1916, 204) is
quite confident that they nest nowhere in British Guiana, beyond which country
their numbers give out rapidly toward the southeast. At times a few birds
work their way farther along this coast, even into the mouth of the Amazon,
and Snethlage (1914, 120) has recorded a specimen taken at Itairuba on the Rio
812 OCEANIC BIRDS OF SOUTH AMERICA
TapajOz, which is one of the south-side tributaries of the Amazon. Never,
however, do such pioneering Brown Pelicans wander as far as Cape Sd0 Roque,
Brazil, where they might perhaps find themselves once more in waters no less
agreeable to them than those of the West Indies.
Near the eastern end of the Caribbean, “‘around the corner”’ from Trinidad,
the breeding range begins, although the pelican colonies have no doubt become
more or less continually reduced in number and restricted in size since the early
days of settlement and exploitation among the islands of the Spanish Main.
Cory (1909, 220) describes a colony in the mangroves at Tortuga Island, Vene-
zuela, where nests containing young birds of various sizes were found on
February 2. The date may or may not have special significance, for pelicans
are highly variable with regard to the reproductive season. Even at a single
locality this may change from year to year, as shown by the observations of
Danforth (1931, 36) in Porto Rico. He found on a small islet off the coast that
forty nests in the tops of trees each contained two eggs on April 2, 1927, while
on March 22 of the following year the same nests mostly held young birds,
including many almost ready to fly. In some tropical localities, egg-laying
seems to take place more or less throughout the year. At Pelican Island, Florida,
the majority of the birds nest in November, but a few delay until April, which
is the usual date for the breeding pelicans of the opposite or Gulf coast of the
peninsula (Chapman, 1908, 96).
Along the western Caribbean shores of Venezuela there are doubtless other
nesting stations, for pelicans are common throughout the chain of islands on
the continental shelf, as well as on the Colombian coast from the Goajira
Peninsula to the Ciénaga Grande. Throughout these waters they are quick to
assemble wherever fishermen draw their nets. Todd and Carriker (1922, 132)
were unacquainted with any Caribbean breeding grounds in Colombia, and
Darlington (1931, 361) states that pelicans do not fly inland up the rivers in
the Magdalena district, as they are so prone to do in many other parts of their
range. Among the numerous small islands in the extreme western part of the
Caribbean, there are almost certainly other breeding grounds, such as Salvin
(1864, 377) describes at islets off Belize, British Honduras.
On the Pacific side of the continental barrier, which is readily crossed by
Brown Pelicans in Panama, breeding grounds are well known at the Pearl
Islands. Presumably there are other colonies to southward, at suitable stations
along the Pacific coast of Colombia and Ecuador, for the Brown Pelicans are
abundant clear down to Point Parifias, Peru, or slightly beyond. They appar-
ently reach the southernmost outpost of their breeding range at Santa Clara
or El Muerto Island, in the Gulf of Guayaquil. Large numbers of pelicans
which I saw packed shoulder to shoulder on sandbars within the mouth of the
Rio Chira, Peru, on January 24, 1925, were presumably of this race, rather than
of the west coast race (thagus) which breeds in great numbers less than two de-
grees of latitude to southward, at the island of Lobos de Tierra. I have seen
no specimens of P. 0. thagus collected to northward of Punta Falsa, latitude 6°
S., just south of Sechura Bay. Neither have I seen specimens of the smaller
BROWN PELICAN 813
northern pelican collected to southward of Talara (4° 30’S.). It is no doubt in
these waters, close to the westernmost projection of South America, where the
Humboldt Current meets and mingles with littoral waters of high average tem-
perature, that the Peruvian and the tropical Brown Pelicans come into contact.
Nothing is known about possible intergradation of the subspecies. It is unlikely
that it occurs, however, for the nesting predilections of the two forms seem to
be rather diverse.
Forbes (1914, 405) has stated that the Peruvian Pelicans not only enter the
Gulf of Guayaquil, but also roost among the trees along the course of the Rio
Guayas. All actual specimens that have been recorded from this region are,
however, of the smaller, northern race. Furthermore, I much doubt whether
P. o. thagus, a bird belonging to an arid coast and to absolutely plantless islands,
would under any circumstances perch upon trees or other vegetation. In the
Humboldt Current region it is noteworthy that two widely distributed tropical
sea birds, namely the Bigiiaé Cormorant (Phalacrocorax olivaceus) and the Blue-
footed Booby (Sula nebouxii), will alight upon posts, spars, wires, or other
man-made structures above the ground, just as readily as they take to limbs
and twigs in regions where trees and.shrubs grow. The endemic Guanay
(Phalacrocorax bougainvillii) and the Peruvian Booby (Sula variegata), on the
other hand, make no use of raised supports of any kind, and never “‘perch’’ on
anything smaller or less substantial than a point of rock. The same difference
is probably characteristic of the respective behavior patterns of the tropical
and the Peruvian Pelicans, the latter being an endemic Humboldt Current bird.
Salvin (1864, 377) writes:
It was a bold Pelican that first perched upon a tree: a bird less adapted to such a resting-place
could hardly be imagined. Yet there they sit on the mangrove-boughs for hours, preening their
feathers with their long hooked bills, an amusement they seem to take special delight in, all the
time keeping their balance with ease, even when a strong wind tries the security of their footing.
While they perch, the hind toe is of course opposed to the others, notwith-
standing the continuity of the web. The tight grip is a natural concomitant of
a pull on the tendons resulting from the weight of the bird. Gosse (1847, 409)
long ago pointed out that when the heel joint of a dead pelican is bent, the
flexed toes close like a vise.
The perching ability of Brown Pelicans at least increases their choice of
nesting sites, and the birds breed, according to circumstance, either on the
ground, in trees, or on the flattish tops of low shrubbery in the manner of the
man-o'-war birds. Sometimes all three types of nest occur within a single
colony. Chapman (1908, 96) believes that arboreal sites are safer, even at
islands unfrequented by predacious mammals. For one thing, it brings the nests
above the level of floods, and pelicans have never shown sufficient perspicacity
to select the higher areas of land in localities where they nest on the ground.
Furthermore, continues Dr. Chapman, the tree-born pelican not only has a
cooler, better-ventilated, and cleaner home, but it also avoids competition with
its fellows before it is strong enough to care for itself. Ground nestlings, on the
other hand, tend to wander away from the home site while they are still young,
814 OCEANIC BIRDS OF SOUTH AMERICA
and thus get themselves into constant difficulties. Fledgling Brown Pelicans
are more or less given to the practice of cannibalism, and many chicks hatched
on the ground disappear sooner or later into the maws of their elders.
Nelson (1911, 393) presents a brief for the other side of the argument. He
states that the youthful arboreal pelicans begin to crawl out on the adjacent
branches as soon as they are slightly steady on their pins but that, like over-
venturesome small boys, they often find themselves unable to return to the cradle
to be fed. When the parents alight on the nest, they may then ignore their
roving chick or, if they finally answer its pleadings and try to feed it by flying
or hopping to the peripheral twigs, the whole family is liable to get into further
trouble. The operation becomes a ludicrous process of balancing for such heavy
and clumsy birds. Furthermore, both before and after feeding, young pelicans
indulge in demonstrative behavior which has a semi-crazed appearance, and
among the twig-walkers this is the cause of much mortality. Some tumble to
the ground, while others hang themselves in the crotches. In the case of ground-
nesters, continues Nelson, the parents can make easy landings and can call up
and feed their young without difficulty. The chicks can wander about and get
exercise, and less harm is likely to befall them during their strange pre- and
post-prandial antics. In windy weather, moreover, they can easily move into
sheltered localities.
At Pacheca and Santelmo, Pearl Islands, Rendahl (1920, 12) found the peli-
cans occupying tree-nests around the outer border of a thinly wooded plateau,
during March. The only breeding station I myself have seen in the Pacific is at
the small island of El Muerto, in the Gulf of Guayaquil. Here, during late
February, 1925, many pelicans were perching in the bushes, close to nests of a
previous year. Because of the phenomenal or practically unprecedented rains of
this season, however, neither the pelicans nor such other resident sea fowl as
boobies or man-o'-war birds were able to hatch their eggs or, indeed, to prevent
them from being washed into the sea practically as soon as laid. I suspect that
the Brown Pelicans may also nest in the forest on the neighboring and larger
island of Puna, as well as on the ground of the small, bare islet of Pelado in the
Bay of Santa Elena, and at the larger, scrub-covered island of La Plata. About
all three of these localities I found pelicans abundant during the early months of
1925 but, because of the rains, they seemed unable to negotiate a successful
breeding season.
The average number of eggs in the Brown Pelican’s set is three, although a
limit of two is not uncommon. Since the nesting season is almost everywhere
prolonged, it is usual to find fresh eggs and well-grown young at the same time.
The period of incubation is said to be about thirty days, during which time the
sitting birds can be found in three characteristic positions. In the most common,
the head is thrown back between the shoulders, with the bill pointing hori-
zontally forward. The second is the so-called posture of sleep, with the head
turned and the bill lying along the full length of the back, partly covered by the
scapulars. In very hot weather the pelicans sometimes hold the head straight
up in the perching position, with the bill turned downward but not quite
BROWN PELICAN 815
touching the breast, the mandibles parted and the pouch palpitating. The
monotony of incubation is relieved by frequent exercise and preening operations.
Sometimes the sitting birds turn their pouches inside out by spreading the rami
of the mandible and pressing the bottom of the pouch against the convexity of
the curved neck. This gesture is followed by an upward jerk of the head
CWilliams, 1931, 67).
Nest relief among mated pairs is accomplished by a ceremony which Chapman
(1908, 96) describes as follows:
Asa rule the bird on the nest is not attended by its mate, who may be feeding, bathing, resting
on the shore, or sailing high in the air. The returning bird alights near the nest and, with bill
pointed to the zenith advances slowly, waving its head from side to side. At the same time the
sitting bird sticks its bill vertically into the nest, twitches its half-spread wings, and utters a low,
husky, gasping chuck, the only note I have ever heard issue from the throat of an adult wild Brown
Pelican. After five or six wand-like passes of its upraised head, the advancing bird pauses, when
both birds, with apparent unconcern begin to preen their feathers, and a moment later the bird
that has been on duty steps off the nest, and the new comer at once takes its place.
Chapman's observations indicate that such ceremonies are omitted when a
sitting male is relieved by the female.
The chicks cry out while they are still imprisoned within the eggshells, and
their first squirmings and wrigglings in the free air are accompanied by grunts,
to be succeeded by the feeding call, which Chapman describes as a piercing
scream. While the young are still small and unfeathered the adults spend much
time standing between them and the sun with spread wings, giving their off-
spring the solace of shade. The impulse behind this is a blind one, however,
for if a camera or other strange object distracts the adults they will stand in the
same attitude on the side of the nest away from the sun, spreading their wings
so as to cast a shadow on the bare ground where the unfortunate chicks can
derive no benefit. As soon as the young can walk, they flop over the side of the
nest and stagger doggedly about, falling over obstacles and getting tangled up
in every vine they encounter. Their peregrinations seem to be aimless within a
limited space; the only sound they make is a hiss (Cahn, 1922, 417).
Feeding of the chicks may go on at any hour, although there are usually
certain times of day, particularly between seven and eight o'clock in the morn-
ing, again shortly before noon, and during about two hours before sunset, in
which most of the food is transferred. The feeding periods are, of course,
correlated with the natural diurnal movements of pelicans. They are early birds
at their fishing, usually leaving the roosts at dawn to forage for a few hours,
returning to the nest about eight o'clock to rest until eleven or thereabouts,
when they go abroad again and fish, or while the time lazily on the sea or shore,
until dusk, at which hour they can be seen flying homeward in long strings
(Gosse, 1847, 409). If noise is an indication of the importance of a meal, that
delivered during the middle of the day takes first rank, because it is accompanied
by a terrific clamor on the part of the young, which are, of course, the noisy
members of a pelican population.
Even more than most birds, perhaps, pelicans seem to be hidebound creatures
816 OCEANIC BIRDS OF SOUTH AMERICA
of the instinctive patterns which determine the course of their lives. Yet the
adults at least recognize their own young, possibly by voice. At any rate,
Chapman found that they do not recognize dead young as pelicans at all, even
though the carcasses lie in their own nests. The chicks, on their part, unques-
tionably distinguish adults laden with fish from those which have none, even
though the difference is beyond the power of a human observer to detect. When
an old bird returns from the ocean to the colony, it is immediately mobbed by
groups of hungry youngsters, each of which endeavors to be the first into the
pouch. The old birds, under such circumstances, beat off most members of the
crowd of besiegers by knocking them on their heads with the beak, thus seeming
to select deliberately the young to which they are willing to relinquish food. The
rejected youngsters stagger off as if dazed by the blows. Cahn has known an adult
not only to beat off a too-persistent alien chick, but to kill it, and even to eat it.
The food brought home by parent pelicans is carried not in the pouch but in
the gullet, and into this the chicks disappear up to their shoulders. After feeding,
and making a good deal of noise about it, the youngsters may lapse into a sort of
semi-consciousness, laying their heads on the ground, while the adults leave the
vicinity in order to bathe or to soar. Chapman adds that the replete chicks, after
recovering from their apparent daze, go through a violent pantomime in which
they swing their heads from side.to side and bite their wings as if in rage.
Although pelicans are gregarious, they can hardly be called sociable, and
the interrelations between families that nest side by side seem to be confined
to occasionally bad-humored tilting or fencing with the long beaks, a custom
which appears to account for the even spacing of the ground-built nests. Their
general psychological responses depend upon the course of events within the
environment. Usually they are extremely tame while they have eggs or chicks
in the nest, but Job (1905, 7) states that if a flood overwhelms the colony, their
conditioned behavior entirely changes with the breaking of the sequence, and
the old birds at once relapse into the shyness of the non-breeding season. Fright
or any undue disturbance causes both adults and young to disgorge.
The flight of the Brown Pelican is both leisurely and extremely powerful,
and their formation of lines or wedges in which the wing-beats make a rhythmic
sequence has often been described. The position and spacing of birds in line is
doubtless determined by requirements of clear vision ahead for all of them, and
perhaps by the nature of the air movements set up by their sweeping wings.
All sorts of invisible currents in the atmosphere are, indeed, their servants,
and the way in which they take advantage of the lift produced by a wave
advancing at an angle against a sandy shore has long been admired. The peli-
cans appear to glide along a breaker in such a manner that the energy born of
lively water, rather than any muscular effort of their own, will carry them for
very long distances without a single wing stroke. Bangs (1902, 395) noted that
pelicans along the east coast of Florida appeared totally unperturbed during a
February gale of extraordinary force and far-reaching effect. At the height of
this storm their bands proceeded up and down the lines of breakers, with almost
the same calm and measured flight as in the finest weather. Nevertheless, the
BROWN PELICAN 817
West Indian hurricanes sometimes strike them down, as has been teported by
Wayne (1894, 85).
The tendency of Brown Pelicans to soar under favorable weather conditions
at a height which may reach several hundred meters has often been noted, and
yet Bryant (1889, 83) remarks that most birds of a certain Lower Californian
colony regularly flew the long way round toward their feeding ground, rather
than take a short cut of one-tenth the distance which necessitated crossing
a range of hillocks about 30 meters in altitude.
In alighting on the water the behavior of a pelican is much like that of an
albatross, for it often lowers its feet and slides for several lengths before it sinks
to the floating position. The inelegant but highly effective diving of the bird
has been much described. To Captain Delano (1817, 379) this process seemed
to partake of
. the manner in which a sailor washes his clothes, by making them fast to the end of a rope
and throwing them from the forecastle into the sea; when they strike the water they spread out,
with the trousers in one direction, the shirt in another, and the jacket in a third.
In the deep and clear cove just to northward of the Puntilla or elongated
tip of Point Santa Elena, Ecuador, I used to watch the Brown Pelicans at close
range as they dived among the fishing-boats, taking every advantage of the
maneuvers of the local Indian fishermen. Frequently the birds would hurtle
from a height as great as 20 meters above the water, usually spiraling or twisting
on their downward course so that they struck with their backs rather than
their breasts toward the surface. In other words, they would be gliding upside
down, with the wings still half spread, at the instant before the plunge. Usually
they quite disappear, even to the tips of their long wings. West Indian tradition
has it that the pelicans sometimes capture fish a full fathom beneath the surface.
The twisting descent is doubtless responsible for the fact that the bird turns
some sort of somersault under water, and comes up heading in another direction
from that of its diagonal dive. Emergence, in fact, finds the pelican facing the
wind and ready for flight, while the plunge is usually, if not always, made
with the breeze astern. As soon as pelicans reappear at the surface, they turn
down the bill to drain the pouch which, according to Gosse (1847, 409), may
hold ‘17 pints’’ of water, after which they toss up and open the bill so as to
release their victim, only to receive it in the throat and swallow it with a gulp.
It is at such times that Laughing Gulls and noddies attempt to steal the prey
of the pelican, sometimes standing upon the latter's head.
At their feeding grounds, Brown Pelicans seem to ignore the small and
light-winged birds, such as gulls and terns, which hunt among them, more
or less at their expense. Perhaps this is because they have learned by ex-
perience that they are unable to do anything about it. With larger com-
petitors, such as boobies, or the herons that attempt to keep them company
in shallow coves of the Pear] Islands, they are far from amicable, and will
pursue them with much saber-rattling, if the snapping of their long bills may
be so called.
Little is known about their natural enemies, though Nelson (1913, 393)
818 OCEANIC BIRDS OF SOUTH AMERICA
states that a plague of mosquitoes at Pelican Island, Florida, during June, 1911,
abruptly terminated all the breeding activities of the pelicans, tormenting them
so persistently that about 600 nests containing small young were abandoned.
If this was the true cause of the departure of these birds, it is probable that
mosquitoes are an important factor in the distribution of their breeding stations.
The pelicans could hardly nest, for example, at any part of the mosquito-
infested mainland shores of Ecuador and Colombia, although at such outlying
islands as El] Muerto and La Plata they would be completely or relatively free
from such insect pests. Brown Pelicans are heavily infested with mallophagan
parasites, chiefly of the genus Menopon, creatures which live not only among
the feathers but also inside the pouch, where they cling in clusters that irritate
and sometimes inflame the integument. Nothing is known, however, about
the relation of the insects to the actual welfare or illness of pelicans.
At times the pelicans suffer from destructive pandemic maladies, to which
many other species of colonial sea birds are likewise subject. Dead examples
are often found inland near Point Santa Elena, Ecuador, and at times, when
the ‘‘peste’’ is rife in northern Peru, their bodies, together with those of cor-
morants and boobies, have been found as far inland as the slopes of the Amotape
Mountains. Widespread mortality among the Brown Pelicans has been noted
for several centuries, for du Tertre (1667, 271) states that during September,
1656, great loss of life occurred among these birds near the southern end of the
Lesser Antillean chain, so that along all coasts of St. Vincent and the Grenadines
the water was strewn with their dead bodies.
Pelicans have not been recorded from Cocos Island, in the tropical Pacific,
which emphasizes the remoteness of the Brown Pelican population inhabiting
the Galapagos Archipelago. Because of the isolation of these birds, and the
fact that their systematic status is still doubtful, I have kept the notes relating
to them separate from those in the foregoing account.
The expedition of the California Academy of Sciences collected pelicans at
18 islands and islets of the Galapagos, and found nests in mangroves and other
shrubbery at Albemarle, South Seymour, Indefatigable, and Jervis Islands.
Gifford (1913, 107) saw adults mating on April 1 and found eggs or young
chicks, or both, during March, April, July, November, and December. Since
Scouler (1826, 211) found many young in the nests at Chatham Island during
January, it is clear that the breeding season at the Galapagos continues through-
out the year. Gifford found a few nests on the ground, as well as others at least
7 meters high in mangroves.
The California Academy naturalists found the Galapagos Pelicans somewhat
warier than the boobies and many other native species. When approached
closely, the pelicans kept their wings trembling as if nervous. They would,
however, decoy readily to wounded birds, and they also proved themselves
scavengers ever ready to pick up the bodies of birds as large as hawks tossed
overboard from the skinning table on the deck of the schooner ‘Academy.’
Noddies often accompanied the Galapagos Pelicans on their fishing excursions,
and Gifford once saw two of the latter sitting upon a swimming pelican’s head.
BROWN PELICAN 819
Rothschild and Hartert (1899, 177) report upon a nest with three eggs, found
among the mangroves of Indefatigable on September 3. The eggs measured
78.5 x 51, 78.5 x 50.5, and 72 x 52.5 millimeters.
PERUVIAN PELICAN
Pelecanus occidentalis thagus
. Pelecanus Thagus Molina, 1782, Sagg. Stor. Nat. Chili, p. 240 (Chile).
Names: Molina's Pelican, Chilean Pelican. ‘‘Alcatraz’’ on the west coast of South America;
‘*Pelicano’’; Chilean fishermen call bands of these birds ‘‘Soldatos Peruanos’’ or Peruvian soldiers;
Molina, who wrote in Italian, termed the species ‘‘il Thage,’’ which accounts for its specific name.
Synonyms of the latter include molinae, nigricollis, landbecki, and barbieri, besides which this pelican
has been reported upon under the name fuscus.
Characters: Similar to the tropical Brown Pelican, but much larger, a distinction no less
apparent in the size of the eggs than in that of the birds. Furthermore, the pale straw-colored
occipital crest is more prominently developed, and the entire brownish black ventral surface is
finely streaked with white, each feather having a narrow shaft-stripe. The bill and pouch, more-
over, are more brightly colored, and there is a considerable growth of caruncles between the base
of the culmen and the eye.
The text and colored plate of Forbes (1914, 403) reveal the extraordinary variation in the color
of head, neck, iris, bill, pouch, and naked skin of the face during the changes incident to age and
season. The iris, which is brown in young birds, progresses toward yellow in mature females and
gray in males. The naked skin about the eye may be black, blue, or carmine, while the orange of
the mandibles and the lavender stripes of the pouch show a wide range in intensity. The legs and
feet of adults are lavender-gray, sometimes with a greenish overlay on the tarsus.
Despite the detailed descriptions by Forbes, Coker, and others, the complete plumage sequence
of this pelican is not yet fully understood. Coker (1919, 487) writes:
‘The following is an account of the color changes as far as I could make them out, by inference
from observation of the group, without the opportunity to trace the history of the individual
birds. With this qualifying statement, I give them for what they may be worth in suggestion to
other observers.
A. The immature bird after leaving the nest is brown with white breast, some buff on the upper
side of wings. Head and neck brown without lateral stripe. Bill green at base and top, sides
orange. Pouch orange-yellow.
B. Nuptial plumage: The feathers of head and neck stripe are yellow; the ‘cravat’ or necklace
of yellow, is formed, while the rest of the neck is a very dark brown, almost black. The covering
of striate feathers on the back and lower side develops, while the mantle of pearly gray completes
the nuptial plumage. The pouch becomes black with blue stripes on the sides anteriorly and the
characteristic red appears on the generally greenish bill. This phase was observed in birds occupy-
ing new-made nests and often in outlying rookeries. No adults of this phase were found on nests
where the eggs had hatched out.
C. After the beginning of the laying, the yellow feathers are shed and replaced by white, which,
however, do not extend so far into the crest nor are so long as the yellow. A ‘cravat’ of greater
or less size may be retained or may be lost entirely. Many of the birds in the nests had heads partly
yellow and partly white. The longer yellow feathers being in patches of greater or less size amid
the shorter crop of whites, the changes do not always occur in just the same order. Thus whitehead
birds may still show some white feathers in the lower side of body.
D. Another phase may be described, but whether it represents a possible stage between (B)
and (C), or an older stage than (C), or is a phase peculiar to one sex, I am unable to say. Birds
in this phase were observed to be brooding. The head and neck stripes are light gray, the neck is
soft gray, the upperparts are generally brown, but a small region of back and breast around the
base of the neck has the typical white and dark brown striate feathers; the breast is generally
white mottled with brown feathers having a white median stripe; the bill is red and yellow, the
820 OCEANIC BIRDS OF SOUTH AMERICA
pouch as in (C) but paler. This phase includes some features of the immature (A), and some of
the typical brooder (C), but the gray neck is characteristic."’
Measurements of a somewhat inadequate series of adults have been listed on page 809.
The eggs are usually three in a complement, departures from that number being discussed in
the text below. They are exceedingly chalky, white over a slightly greenish base, but quickly
become soiled with guano. The form is highly variable, some having two ends of almost equal
size, and they are much larger than those of the tropical Brown Pelican. Coker found one which
measured 97 x 62 mm., and weighed 198.5 grams, but this was exceptional. Average dimensions
are 79.9 x 55.6 (Coker) and 83.7 x 55.7 (Forbes). The extremes among 10 from Lobos de Tierra
are 86 x 58, 76 x 55, 80 x 53, and 78 x 58 mm. Their weight averaged 149 grams.
Distribution: Coasts of Peru and Chile from northern end of the Humboldt Current southward
to Corral, and casually farther; breeding, now or formerly from Lobos de Tierra Island southward
to islands off the middle Chilean coast, Mocha marking, perhaps, the southern extreme.
The Peruvian Pelican, or “‘Alcatraz,’’ is by far the biggest and most con-
spicuous bird to be encountered in flock formation along the desert coast of
western South America. It instantly reveals its identity as far as the eye can
reach. It is, indeed, one of the world’s largest pelicans, exceeding in size even
the White Pelican of North America. A male and female which I shot at Lobos
de Tierra on January 10, 1920, weighed respectively 7030 and 5055 grams. The
indicated relationship between the sexes is apparently the normal one, for
pelicans differ in this respect from their relatives, the boobies and man-o'-war
birds, among which females surpass males in size. Young Peruvian Pelicans,
according to Coker (1919, 486), are even bulkier than their elders. He records
a fledgling which tipped the scales at 16 pounds or 7257 grams.
In habits and appearance the Peruvian Pelican generally resembles the smaller
Brown Pelican of the tropical coasts to northward, although its color pattern is
subject to perhaps even more extensive variation due to age and other causes.
The white or yellow head, with a tuft or topknot, the yellow necklace, dark
brown nape, and the blue, green, yellow and orange or reddish hues of the great
bill and pouch, are striking marks. Forbes (1914, 405) believed that either three
or four years’ growth was required for the attainment of fully mature plumage
and skin colors.
Forbes and Coker, whose works have just been cited, are the two authors
who have set down the most detailed information concerning the Alcatraz in its
native waters, and in the present biography I have added many of their field
observations to my own.
Along the arid shores of Peru and northern Chile, the Alcatraz is strictly a
littoral bird of the Humboldt Current zone. Its range ends, as previously noted,
near the westernmost projection of the continent, where cool waters give way
to warm. Furthermore, it does not stray out of sight of the coast, and hence has
never been recorded from any of the more distant outlying islands, such as San
Felix or Juan Fernandez, nor even, so far as I can learn, from islets as near the
continent as Hormigas de Afuera. In north-south extent the range is practically
identical with that of the Guanay (Phalacrocorax bougainvilliz) and the Piquero
(Sula variegata), both of which are likewise endemic Humboldt Current forms.
In certain years non-breeding pelicans, including particularly great numbers of
PERUVIAN PELICAN 821
immature birds, wander long distances beyond the limits of the breeding range.
At the northern end they do not penetrate far into tropical waters, so far as we
know, for indubitable records of the race are still lacking from any part of
Ecuador, or even from the Peruvian coast between Point Parifias and the Gulf
of Guayaquil. To southward, however, they travel regularly down the Chilean
coast, sometimes appearing in vast flocks in the harbors of Antofagasta, Co-
quimbo, Valparaiso, Talcaguano, and Corral. During the Brewster-Sanford
Expedition, Beck even encountered eight pelicans fishing together off Ancdd,
Chiloé Island, on May 1, 1914. This seems to be the most southerly record except
for a thoroughly lost individual recorded by Dabbene (1902, 396), which was
captured at Picton Island, at the eastern end of Beagle Channel, Tierra del
Fuego, during the month of February.
In the main, the published records for the southerly Chilean coasts seem to
pertain to the winter season or else to be based upon immature birds. Nicoll
(1904, 52) states that most of the numerous pelicans he saw in Valparaiso Bay
during mid-February were young birds. Such bands seem to be fond of coming
ashore to rest and to stand about among the gulls and Limicolae on the sandy
beaches of remote and quiet coves. They are also quick to take advantage of
artificial sources of food which may supplement their natural diet of fish. Beck
found that, like the Cape Pigeons and Giant Fulmars, the pelicans would hang
about Chilean whaling stations with the hope of picking up scraps of blubber
or other refuse. Hill (1860, 75) states that about the middle of the last century
pelicans not uncommonly wandered even into the streets of Arica where, because
of their recognized importance as guano birds, a fine was imposed upon any
person who harmed them. This did not prevent the direct or indirect destruction
of great numbers of pelicans at the guano islands during the same period, but it
at least indicated an appreciation of the economic importance of the bird, and
represented a forward step from the time when the people of Chile made lanterns
and pouches from the gular sacs of pelicans, as reported by Molina, the original
describer of the form. Another unjustified economic use to which the pelicans
have been put, even within recent times, is related by Coker, who states that
many a Peruvian fisherman or guano laborer has gone out to the Lobos Islands
with a straw mattress and returned with a feather bed! Still another toll from
which the pelicans formerly suffered during a long term of years was due to the
use of the albumen of their eggs in clarifying wine. All such destructive prac-
tices have, of course, been stopped in Peru since the establishment of the Na-
tional Guano Administration which now has control of all the islands.
Like most of the other Peruvian guano birds, the pelican carries on the re-
production processes throughout the year, though least prolifically in the winter
season, May to September. During March and April, 1907, Coker found thou-
sands of eggs, and young birds in all stages of growth, in the colonies at Lobos
de Afuera. In the following December there were again vast numbers of eggs
and naked nestlings, while on June 18 of the same year chicks changing from
woolly down to contour plumage covered a small islet off the Chinchas.
The Peruvian Pelicans breed, or have bred, at practically all the groups of
822 OCEANIC BIRDS OF SOUTH AMERICA
islands along the shores of Peru and northern Chile. It is possible, or likely,
that they have also occupied many more or less inaccessible headlands of the
continental coast, as inferred by Forbes. Little is known about this, beyond
the fact that ancient deposits of guano have been found on the mainland as
well as on islands. It is worth keeping in mind, however, that on these
shores, which are at the brink of the geosyncline, frequent seismic disturb-
ances, or gradual upthrusts, may have changed many recent insular fragments
into present peninsular appendages. Alacran Islet, off Arica, has been the
site of the southernmost large insular colony of which I find a record, but
Mr. Bullock’s manuscript notes report that a few of the birds formerly nested
at Isla Muerta, off the island of Mocha (38° 20’ S.). During December the
inhabitants gathered their eggs, which were known as ‘‘huevos de yegua’’ or
mare's eggs.
From time immemorial the center of pelican population seems to have shifted
from year to year or, at any rate, from decade to decade, up and down the
Peruvian coast. During recent years the principal headquarters have been at the
two Lobos Islands in the north, particularly at Lobos de Afuera, but apparently
it has not always been so. Much of the variation has rightly been ascribed to
the effects of persecution of the pelicans during guano operations. It is evident,
however, that natural causes, especially such as are related to cyclic climatic
changes, have also had an important part in the shifting of the populous
‘“pelicaneries.”’
When I resided at the Chincha Islands late in 1919, for example, most of
the birds inhabiting the flat pampa of all three islands were Peruvian Cormorants
or Guanays. I was reliably informed, however, that throughout all or most of
the years between 1894 and 1911 the pelicans had occupied the greater part of
the north island, the Guanays being confined to the outlying farallones. Then,
in November, 1911, the ‘‘peste’’ killed off the resident birds in vast numbers.
Forbes reports that the surviving adult pelicans abandoned their eggs and
chicks, all of which perished. A similar loss of life occurred, in greater or less
degree, at other breeding stations along the whole coast line of the Republic.
No colonial sea fowl returned to nest at the Chinchas until nearly a year after
the catastrophe, and then it proved to be not the pelicans but the cormorants
which established the dominant foothold. To this day the latter birds have
never lost it at the Chinchas.
A most interesting, and hitherto overlooked, point concerning Forbes’s
account of the holocaust of the birds in 1911 is that the date was exactly two
‘‘seven-year cycles’’ earlier than the similar but even more marked destruction of
Humboldt Current bird life which began in January, 1925. Furthermore, as
shown by the summary of Sheppard's observations in Part I, the same phenomena
were repeated again in 1932, seven years after the disturbances I had the good
fortune to witness in 1925.
There are reasons for believing that in past times the pelican was an extremely
important guano-producer, perhaps even the bird of first rank at many islands
along the whole length of the Peruvian coast. Certainly the Incas and their
PERUVIAN PELICAN 823
predecessors held it in high regard, as indicated not only by the traditional
laws for its protection but also by the preponderant use of the pelican design
in pottery, textiles, and other artifacts. Moreover, the mere size of the pelican
would give it a competitive advantage over other guano birds under conditions
in which the balance of nature had not been upset by man. In November, 1919,
for instance, I saw a few hundred pelicans and a much larger number of boobies
occupy simultaneously a certain area of flat ground on the south island of the
Chinchas. The boobies selected sites and produced eggs first, but within a month
most of their nests had been trampled out of existence by their huge, clumsy
neighbors. In the end, the pelicans obtained exclusive possession of all the
open ground, leaving to the boobies only a fringe of nests containing downy
young within a meter or two of the brink of the cliff. The actual jumping-off
place was avoided by the pelicans, but was no less acceptable than the ledges
beyond to the boobies. Such competition is doubtless one of the agencies which
make the Peruvian Boobies almost exclusively birds of the precipices, for I
observed that they were qtite ready to spread out on to the flat pampa of the
islands wherever conditions were favorable.
On the other hand, in competition with the presence of human beings, the
timid pelican is invariably the loser, and thick beds of bones in hollows and
gulches tell of hordes of young pelicans which have come to an untimely end.
Thousands of these, it is said, were driven to slaughter by wanton guano con-
tractors in the old time, purely for the sake of getting them out of the way of
the diggers. Even where no harm is intended, the pelicans are not easily recon-
ciled to human disturbance, and Coker found that removal of the guano from
a pelican colony was usually the signal for a complete change of location by
the birds for the following season. The pelicans invariably give the impression
of being the shyest and stupidest of the guano birds, and by all odds the least
practical from an industrial point of view. It is difficult to come anywhere near
them without having them dash away, bumping into each other on the ground
or in the air, and leaving their offspring to the voracious gulls. This is so likely
to occur that they should never be approached without the utmost caution.
Before taking flight, they usually open their great bills wide and empty them-
selves of a bellyful of fish. Sometimes even those soaring overhead express their
excitement in the same way, sending down a fearful rain of anchovies or
anchovy paste!
Between the visits of Coker in 1906 and myself in 1919, the pelican had fallen
in rank from the second in importance of the guano-producing birds to a poor
third. Considerable bands continued to nest on islands along the central part
of the Peruvian coast, such as Santa Rosa, San Gallan, the Ballestas, and the
Chinchas, but more and more the headquarters of the species tended to become
concentrated at the Lobos Islands near the northern end, where throughout
many years no guano extraction was undertaken.
During my own field work there were eight well-distributed pelican colonies
at Lobos de Tierra, none of which comprised more than 200 pairs and nests.
Lobos de Afuera, however, supported an impressive aggregation, which may
824 OCEANIC BIRDS OF SOUTH AMERICA
have numbered 50,000 nests or fully 200,000 birds, upon the northern half of
the western island. The sight of 10,000 incubating birds in one small valley,
or of massed fledglings upon the hills beyond, or of the armies of adults that
poured in from sea in stately and deliberate files, is one never to be forgotten.
We know from the careful records of Coker how such a colony reacts to guano
operations, and it is safe to say that the pelicans of Lobos de Afuera can be
saved from serious diminution only if extraction is conducted in such a manner
as to leave one of the two main islands always undisturbed. Under such cir-
cumstances, it might be supposed that the pelican population and the guano
supply would fluctuate only with relation to the one bad year in each seven.
In January, 1920, the pelicans of Lobos de Tierra were nesting in the hollows
in large, irregular packs, which were usually considerably longer than wide.
Other nests covered the old pier or stretched along the railways built for guano
cars. Parts of the track were completely buried under new guano. In the de-
pressions of the island most of the nests contained eggs, or purple, naked young,
but on the embankments and hilltops stood droves of awkward, woolly, white
youngsters, which looked like sheep rather than birds, and which made the
vicinity sound like recess time in the playground of a school. Hundreds of
adults alighted among these chicks while I was using a motion-picture camera,
and not a few of them revealed their strangely unintelligent temperaments by
viciously biting half the young birds within reach.
The Peruvian Pelicans, whether nesting or not, spend a good deal of time on
the islands, and are commonly seen standing in solemn groups on some rock or
point commanding the ocean. Unlike the cormorants, however, they do not
all come ashore to roost. I have sometimes encountered them asleep on the
water in the middle of the night when, from the low level of a launch, their
great floating bodies loomed up startlingly, like hulks of derelicts.
They like, too, to bathe and splash in quiet coves, especially in the morning.
Afloat they seem less timid than while at the nest, and they soon learn to ignore
the close proximity of small craft and swimmers. In the smooth water just
outside the line of breakers they may often be seen riding sedately, and reaching
for bottom life with their long mandibles instead of diving from flight. At
times they will also join with other sea birds in hot pursuit of a rapidly moving
shoal of anchovies, under which circumstances the pelicans usually swim and
scoop instead of plunging. They preen their feathers scrupulously while float-
ing, as well as ashore, and they also yawn, point up and rattle their mandibles,
and make the flabby integument of the pouch shake like a loose sail.
But to travellers along the coast, the Peruvian Pelican is most familiar in
flight. Long files moving with slow, forward-striking beats give, as Coker
remarks, a false appearance of leisureliness, for they are rarely passed by the
“‘swift-winged’’ birds of smaller size. When atmospheric conditions are favor-
able, they often soar in circles above their islands, every now and then beating
the wings four or five times in order to maintain momentum. They are quite
capable of seemingly difficult contortions in the air, such as the feat of scratch-
ing the head with a claw without losing a stroke or changing place in the flight
PERUVIAN PELICAN 825
formation. The pecten on the middle nail of most of the birds I examined was
clogged with down and fragments of feathers, showing its use in allaying the
itching caused by the pelican’s notorious horde of bird-lice.
Only on the ground, at the moment of leaving it or descending to it, and
during performance of the dive, does the pelican lose its grace and dignity. In
quartering the water for prey, its habits and antics are very similar to those of
the tropical Brown Pelican. The sighting of fish causes it to apply the brakes,
tilt up in front, spread the tail, and tread the air with its feet. The beginning
of the plunge may be accelerated by one or two strong wing strokes, after
which the bird hurtles headlong, with the wings at least half extended, and
strikes the water with a vast, resounding splash. As a rule, the Peruvian
Pelicans do not disappear completely beneath the surface, as the tropical pelican
so frequently does. Coker, indeed, believed that they never pass altogether out
of sight, but this is erroneous, for on November 7, 1919, I saw all the members
of a small flock in the bay of Callao fully submerge themselves, not only once
but repeatedly. The variation doubtless depends upon the depth-plane of
available fish. Forbes writes:
When it has secured its prey, the Pelican rights itself on the water, but has generally to delay
several minutes in properly disposing of the contents of its gular pouch before taking wing again.
Its manoeuvres, after a rather successful haul out of a dense shoal of anchovetas, when sometimes
it captures enough to weight down its pouch for a foot to a foot and a half, are ungainly. It tosses
aloft its huge beak fully agape, shaking its head from side to side to tumble its contents throat-
wards. To get them properly arranged seems always an awkward and difficult task, and it has
often to discharge the whole bagful out on the sea again and re-pick them up.
The height of the pairing period for the Peruvian Pelicans seems to come in
October. At this season the birds assemble on their chosen nesting grounds,
and claim their sites. Much tilting with the long bills takes place at this time
and continues, indeed, throughout the nesting term, four or five adjacent birds
sometimes indulging in what looks like mass fencing. The length of the necks
and bills thus determines the spacing of the nests, which are, nevertheless, ex-
traordinarily close together. Coker states that they average about two to each
square meter of surface, whereas those of the Peruvian Cormorant average three.
They are less evenly distributed than those of the cormorants, however, for even
in large colonies, such as that of Lobos de Afuera, the pelicans tend to form many
separate masses or nuclei of nests, rather than to cover a large surface uniformly.
The beginning of each nest is a hollow scrape in the sand or guano. It seems
absurdly small, in comparison with the bulk of its maker, being only about
25 centimeters in diameter. The concavities are more or less lined with feathers,
among which the moulted tail quills of the Guanays predominate. Coker states
that the pelicans also carry dry guano and sand to the nests in their gular
pouches, and build up the outer rims into slight mounds, which grow further
through the copious defecation of the sitting birds. At stealing feathers and
pebbles from the foundations of neighboring nests, the pelicans are as adept as
any of the other guano birds. The colonial habitus is not accompanied by any
reactions which might be termed either altruistic or codperative.
826 OCEANIC BIRDS OF SOUTH AMERICA
Eggs appear about three weeks after occupation of territory. Three in a set
seems to be the commonest number, although I have seen many heavily incu-
bated clutches of two. Among 207 nests examined by Coker, 35 contained one
egg, 73 two, 84 three, 10 four, 4 five, and 1 six. Since these counts were made in
a group in which incubation was well under way, the number in a nest was
probably definitive, except as affected by accident. Coker also discovered two
nests containing eight eggs each. He opened the eggs of one of these sets and
found that they all contained live embryos at practically the same stage of
development. Coker also carried out experiments to show that two or more
days intervene between the laying of successive eggs.
The young, which are flesh-colored when hatched, undergo a rapid pigmen-
tation of the skin, which turns dark blue or purple. Forbes states that they
remain callow for about two weeks before the white down begins to cover
them. They grow to nearly adult size before the first feathering appears on the
wings and back.
Coker thus describes some of the extraordinary actions of these birds on their
breeding territory:
The behavior of the pelicans on the nesting grounds in some respects appears stupid and in-
explicable. An alcatraz on her nest will sometimes reach over with her long neck and bill, take a
fledgling from the uncovered nest of a neighbor and throw it away, perhaps into another nest.
Once, within a space of 2 square meters, I saw six little ‘‘pichones,’’ almost new born, bandied
about in a most merciless way, tossed from one alcatraz to another, each seemingly unwilling to
have the little birds in her proximity. Finally three of the fledglings were thrown beyond the mar-
gin of the nesting ground and left to die in the sun. I watched a pelican that returned to a nest
from which the only fledgling had been transferred by a mischievous neighbor into an adjoining
nest. The returning brooder did not appear to notice the loss, but sat composedly on the remaining
egg; then, pilfering on her own account, she quietly reached over and stole all of the feathers from
the nest in which lay her own offspring (supposedly) among others, to add to the lining of her
nest. I questioned if the birds invariably occupied the same nest; on one occasion, at least, a bird
was seen to brood on two different nests. The birds near the margin had been frightened away, but
most of them returning, all of the nests were soon reoccupied except the ones nearest to me. An
alcatraz, after sitting for 15 minutes on one nest, moved slowly over to another nearer to me, while
its place on the first nest was at once taken by a bird that was previously covering an empty nest.
The young were trampled dangerously by the old birds as they moved awkwardly about. Perhaps
these are abnormal actions, attributable to nervousness caused by the presence of an intruder.
The young Peruvian Pelicans develop in due course the wandering propen-
sities already described in the account of the tropical Brown Pelican. While
they still look more like woolly lambs than birds, they form flocks on the
slopes and ridges above their nests, and keep up a piping which suggests a frog-
pond. How, or whether, the returning adults recognize their own offspring is
uncertain. In feeding, the chicks practically dive into the gaping mouth of the
adult which, as Forbes writes, sometimes has to prostrate itself on-its belly to
allow free access to the capacious store-chamber. At the slightest alarm, the
young eject their repast, a fact of which not only the Indian fishermen in search
of bait, but also the Kelp Gulls, take advantage. The latter are ever ready to
bully a young pelican into laying a banquet at their feet.
The ‘‘anchobeta’’ (Engraulis ringens) makes up a large portion of the Peruvian
PERUVIAN PELICAN 827
Pelican’s food, although it also captures much larger fishes as well. Coker saw
one regurgitate a mullet more than 30 centimeters in length. An example I shot
at Lobos de Tierra contained in its stomach two needlefish (Tylosurus stolzmanni),
the size of which I unfortunately did not record. Forbes once observed a
pelican snatch an eel from the beak of a Bigiia Cormorant. As a rule, however,
it is rather a case of other birds robbing the pelican, and Nicoll (1904, 52) saw
a Kelp Gull actually alight upon a pelican’s head with the object of picking
fish from its bill.
Gulls of two species (Larus dominicanus and L. belcheri) and Turkey Vultures
are the pelican’s most formidable enemies ashore, for all three of these pre-
dacious birds devour its eggs and newly hatched young. So bold and avid are
the gulls, and so relatively timid the nesting pelicans, that it is a serious matter
for a naturalist to attempt to examine their nests too closely. Feral cats, ac-
cording to Coker, have also wrought much havoc among pelicans of the Lobos
Islands. The place of Mallophaga as enemies is problematical. The plumage
of the pelicans, and the ground of the rookeries, swarm with them, and they
form clusters inside the pouches of both adults and young. No doubt they
are annoying, and many observers have believed that the beating and splash-
ing of the bathing pelicans is in part a delousing effort. However, the
Mallophaga are ‘‘normal’’ parasites, and there is thus far no evidence that
they carry organisms of disease, or produce any worse effect than local irrita-
tion of the skin.
Coker states that the pelicans clearly take cognizance of sharks, and it is
known both from his observations and from a photograph published by
Chapman (1924, 328) that the birds are occasionally slain by sea-lions. The
eviscerated condition of dead pelicans found afloat or on the beaches suggests
that the fish-filled belly of the pelican, rather than the flesh of the bird itself,
is the lure which occasionally tempts the sea-lions to attack them.
THE BOOBIES
FAMILY SULIDAE
Two comprehensive genera of this family are recognizable, of which the
true gannets (Morus) are of temperate range in the North Atlantic or belong
to somewhat similar, relatively cool-current regions in southern Africa, south-
ern Australia, and New Zealand. The boobies (Sw/a), the common name of
which comes from the Spanish “‘bobo,”’ a dunce, are pan-tropical in all oceans.
The field of this book has representatives of each of the three cosmopolitan
species of boobies (dactylatra, sula, and leucogaster), as well as two very distinc-
tive species (nebouxii and variegata), which are confined, respectively, to warm
and cool areas of surface water off the western coasts of Middle and South
America. Furthermore, a well-defined race of the Brown Booby (/eucogaster)
has an extraordinarily restricted range in the rainy northwestern bight of the
My wh iy Hh
| i iH
Fic. 68. Sourn AMERICAN Boosts.
Dorsal and ventral aspects of six forms. Reading from left to right: upper row, Brown (Sula
leucogaster leucogaster) and Colombian (S. leucogaster etesiaca, male); second row, Blue-footed (S.
nebouxii) and Peruvian (S. variegata); lower row, Red-footed (S. sula, in the white phase) and Masked
(S. dactylatra).
[ 828 ]
THE BOOBIES 829
continent, a district bounded by the Pacific coasts of Panama, Colombia, and
Ecuador, and the islands of Cocos and Malpelo ().
In general, the distribution of certain boobies is clearly to be correlated with
that of particular food organisms, such as flying fish. Others, of which the
above-mentioned Colombian Booby (Sula leucogaster etesiaca) is the best example,
are imprisoned, so to speak, within definite climatic and hydrographic regions,
and the nature of the bonds is not yet understood. The distribution of one
species (Sula sula), the only tree-nester in the family, is determined in Jarge part
by the vegetation existing on islands throughout its world-wide range.
In degree or extent of speciation the boobies have surpassed the man-o'-war
birds and the American Brown Pelicans. Their variety of proportion and
plumage-pattern resembles, rather, that of the marine cormorants. They pre-
sent, nevertheless, a few complex taxonomic and biological problems, the most
outstanding of which concerns the status of the several color phases of the
Red-footed Booby (S. sula), which have been described under numerous sub-
specific and even specific names. An answer to the many questions involved
will, indeed, require more information and a fuller representation of specimens
than have thus far been focused upon them. A study of the three or more
American races of the Brown Booby, in connection with the differing geographic
characteristics of their respective ranges, also promises conclusions of wide
significance.
Our most detailed knowledge regarding the life history of the Sulidae has
been derived not from the typical boobies, but from observation of the related
Northern Gannet (Morus bassana). Gurney (1913) reports that in this species
the single, notably small-yolked egg is incubated for 42 days, and that the
whole cycle of the breeding season lasts 4 months or longer. The fledglings
are abandoned by the parents when they are 12 to 13 weeks old, at which time
they are considerably heavier than adults. Thereafter, like young petrels, the
chicks starve and lose weight for 10 or more days, before finding their own way
to the sea, where for a time they lead an exclusively swimming life. Fully
adult plumage is not attained until the third year. Gannets, according to Gur-
ney, can neither hear well nor smell well. Despite the fact that they are usually
classed as “‘surface-feeders,’’ they have been captured in nets set as deep as
27 meters, indicating powers of submerged progression comparable with those
of cormorants.
BLUE-FOOTED BOOBY
Sula nebouxit
Sula nebouxii Milne-Edwards, 1882, Ann. Sci. Nat. (Zo6l.), (6) 13, Art. 4, p. 37, pl. 14 (Pacific coast of
America).
Names: “‘Camanay’’; in Ecuador and northernmost Peru, ‘‘Piquero,’’ a name reserved else-
where for Sula variegata. A synonym of the specific name is gossé.
Characters: A brown and white booby of somewhat streaked appearance, with alarge whitish
patch at the junction of neck and back and with bright blue legs and feet.
Adults (sexes alike except as to size, and the appearance of the eye): Head, upper part of neck,
and sides of lower neck cinnamon-brown, more or less mottled because each of the narrow, pointed
brown feathers has its middle and tip white in fresh plumage; anterior part of forehead, throat
830 OCEANIC BIRDS OF SOUTH AMERICA
behind the gular sac, base of hind neck, rump, and upper tail coverts mostly white; ventral surface,
axillaries, and innermost under wing coverts white; dorsal surface, except as noted, and wings,
brown, each feather of the back and scapulars shading into whitish toward the extremity; primary
quills blackish brown; secondaries cinnamon-brown; central rectrices mainly whitish, but shading
into brown on the distal portions of the outer webs; outer pairs mostly brown, more or less white
along the proximal half of the shafts. Iris yellow, that of the female with blotches of black pig-
ment which appear to blend with the pupil; skin of face and gular sac slaty; bill dull greenish blue;
legs and feet ultramarine blue, sometimes slightly greenish on the webs.
Coker (1919, 473) states that males of this species have consistently darker heads than females,
a distinction not previously reported. Individual variation, as well as the effects of wear, appear to
show in the intensity of coloration. Certain examples from the Galapagos and the Gulf of Guaya-
quil are remarkably white-headed and white-throated. It is possible that Galapagos birds average
somewhat larger than any from the continental littoral, but more specimens would Ps needed to
establish this. Very old tail quills sometimes fade almost white.
7 males from the coasts of Panama, Ecuador, and Peru: wing, 387-413 (403); an 165-218
(190.3); exposed culmen, 94-106 (99.7); tarsus, 47-54 (50.4); middle toe and claw, 77-88 (81. 8) mm.
7 females: wing, 403-426 (416); tail, 165-215 (190); exposed culmen, 106-109.5 (107.5); tarsus,
51-57 (55); middle toe and claw, 83-91 (88.3) mm.
3 males from the Galapagos: wing, 406-433 (422); tail, 171-226 (204.7); exposed culmen,
103.5-107 (105.2); tarsus, 50-53 (51); middle toe and claw, 80.5-84 (82.8) mm.
3 females: wing, 444-448 (446); tail, 212-243 (224); exposed culmen, 114-115 (114.8); tarsus,
51-54.6 (53.2); middle toe and claw, 90-95 (92) mm.
Two males which I collected at Lobos de Tierra Island in January weighed 1340 and 1350 grams;
two females from the same island 1660 and 1750 grams.
In immature examples the head and neck are darker brown, the back and wings grayer than in
adults. The iris is brown; feet grayish blue. Downy chicks are pure white.
Eggs number from 1 to 3. (At Lobos de Tierra Coker counted, among 39 nests, 12 containing
3 young birds, 19 with 2, and 8 with 1.) The eggs are pale blue, as the result of the thin chalky
coating that covers the distinctly blue shell. The form is variable, but inclines toward elongate-
ovate. Examples measure 64 x 40, 67 x 39, 65 x 38 (one set); 63 x 41, 60 x 44; 65 x 40 mm.
(Coker).
Distribution: Breeds from the Galapagos Archipelago, and the Lobos Islands off northern
Peru, northward along the west coast of America to islands in the Gulf of California. Apparently
confined as a nesting bird mainly to arid or semi-arid districts, though reported also from such an
extremely humid station as Gorgona Island. Wanders casually, and in only small numbers, to
southward of the breeding range.
The ‘‘Camanay”’ is the Blue-footed Booby of American ornithological books,
and is the only one of the Peruvian guano birds which belongs also to the
fauna of North America. Unlike the Guanay, Alcatraz, and Piquero—that is,
the cormorant, pelican, and booby of the Humboldt Current, which comprise
the great guano-producing triumvirate—it is not a characteristic species of the
cool-water belt off western South America. Its range, on the contrary, is con-
fined rather definitely to the Tropical Zone, between the southern waters
of the California Current and the northern extremity of the Humboldt
Current. Although it is credited in ornithological literature with inhabiting
the Pacific ‘‘between Lower California and Chile,’’ it is, as a matter of fact, a
relatively rare bird south of northern Peru, and it apparently finds its southern-
most breeding limit at Lobos de Afuera (6° 58’ S.). A considerable colony
occupies a headland on Santa Clara or Amortajada Island, in the Gulf of
Guayaquil; other breeding grounds are known at the Galapagos, and thence
BLUE-FOOTED BOOBY 831
northward to the Revilla Gigedos and to arid islands within the Gulf of
California.
Despite the long breeding range thus recorded for the Blue-footed Booby,
the fact should be emphasized that it is a bird of by no means continuous dis-
tribution, for the reason that it seems to avoid, in the main, habitats in the
most humid regions, confining its nesting chiefly to bare islands or at least to
those with trees and lesser plants of a scrubby and xerophilous type. Thus it
finds no available home at Cocos Island, nor in most parts of the wet coastal
district of northern Ecuador and Pacific Colombia. Strangely, however, it is
reported as a resident of Gorgonilla, the southerly projection of rainy Gorgona
Island, and the meaning of this departure from the usual type of environment
is still obscure. At the Pearl Islands are stations, such as Pacheca and Galera,
capable of supporting a considerable population. The Galapagos Archipelago
also furnishes plenty of suitable nesting grounds, and nearer the continental
coast these begin as soon as one passes to southward of the zone of more or less
perpetual rainfall. At La Plata Island, Ecuador, for example, the perennial
vegetation consists largely of cactus and drought-resisting thorn-scrub, while
the lush green ground cover is ephemeral, depending chiefly upon heavy rains
which come at seven-year intervals. Here the Blue-footed Boobies find, perhaps,
their most northerly breeding ground on this coast. When I visited the island
in February, 1925, the lighthouse keeper led me to a pampa above the northern
shore where there were many of the unmistakable white-ringed ground nests of
this species, left over from an earlier season. No birds were in residence at the
time, although the White Boobies (Sula dactylatra) had fresh eggs in another
part of the island. Possibly the phenomenal rains of that year were interfer-
ing with the breeding of the Blue-footed species, as they undoubtedly were
farther southward at El Muerto in the Gulf of Guayaquil, and at the Lobos
Islands in Peru.
During the same month I found many of these birds on the bare islet of
Pelado, in Santa Elena Bay, but here any new eggs would certainly have been
washed into the sea by the deluges which had cut deep gullies in the guano-
covered surface. At El Muerto, a few days later, we found Blue-footed Boobies
in abundance, but here the rains were not only preventing them from nesting
but were also causing the death of great numbers through landslides. Large
sections of the silt-like cutbanks were collapsing every night. Since the Blue-
footed Boobies roosted chiefly along the edges, they were carried down by
hundreds, and in the heaped-up soil at the base of the cliffs along the north-
western coast of the island, I found many score of the boobies crushed or smoth-
ered to death, and a few still alive though hopelessly entrapped.
My observations at El Muerto convince me that this species is much out of
place in any region of rainfall and shrubbery. That a booby may become a
tree-living creature is demonstrated by the Red-footed species (Sula sula), which
not only perches well but is also a quick and lively twig-hopper. It has even
forsaken the ground entirely in its nesting. The unfortunate Blue-footed
Booby, however, is obviously in an awkward stage of its evolution whenever
832 OCEANIC BIRDS OF SOUTH AMERICA
it encounters vegetation. It aspires, so to speak, to become a perching bird,
but its success is negligible when compared with that of the Red-footed Booby
or even of its more distant cousin, the Brown Pelican. It seems quite incapable
of ever reaching a balance on a small limb, and I saw several come to grief
while attempting to alight in the sparse bushes of E] Muerto. One became
entangled among the branches before our eyes, and hung there for more than
an hour. It would surely have died, as several of its fellows had already done,
if we had not sent the lighthouse keeper's son to release it. At E] Muerto in
1925 the Blue-footed Booby seemed, indeed, to be a personification of ill-
adapted misery, suffering alike from the rains, the landslides, and the vegeta-
tion, besides which the man-o'-war birds certainly victimized it more than
they did any other species. Furthermore, at least one individual was seen to
be drawn under the surface of deep water close to the island, while it struggled
desperately in the grip of a shark or some other large fish.
For a picture of the Blue-footed Booby under more happy circumstances, it
is necessary to go to Peru, where the two Lobos Islands furnish one of the
principal headquarters of the species. Here during seasons of normal rainfall
(which means no rainfall), they nest by thousands throughout the year, with
practically all inimical factors concentrated in a single foe, the Kelp Gull, which
feeds largely upon their eggs and newly hatched chicks.
Such a buffoonish sort of bird, possessed of feet of a completely incredible
color, could hardly have escaped notice by the literary seafarers of an earlier
day. Therefore, while this species was not technically described until 1882, it
is not surprising to find that Captain Amasa Delano (1817, 380) has written as
follows about the birds as he observed them at the Galapagos Islands during
the year 1801.
They resemble the small kind of booby, and something similar to the kind which is described
at the Lobas Islands, called Bonaparte’s army, excepting they are of rather a darker colour on the
breast and neck, and their beaks and feet are of a Prussian blue.
There are also numerous other early references, such as that of Scouler (1826,
211), who found the Blue-footed Boobies common at Chatham Island, Gala-
pagos, during January.
During the Brewster-Sanford Expedition, Beck collected but a single speci-
men of this booby, an immature bird shot off Ancén, Peru, among groups of
the far more common S. variegata. During my own work, I encountered the
Blue-foots from the vicinity of the Bay of Ferrol northward, and obtained
examples at Lobos de Tierra and in Ecuador. The Museum has additional speci-
mens from the Galapagos, Panama, and from various islands off the west coast
of Mexico. It is interesting that while this booby is common on islets close to
the Pacific entrance of the Panama Canal, it has never been recorded from the
Atlantic side. The Isthmus apparently acts as an effective barrier to every form
of booby except Sula sula, though it is doubtful whether individuals of even
the latter fly across it, as the pelicans and man-o’-war birds regularly do.
Little that is new or noteworthy is indicated by our specimens, beyond the.
suggestion that the well-isolated Galapagos representatives of the species may
BLUE-FOOTED BOOBY 833
prove to constitute a distinct subspecies from those of the continental coast.
They seem, at any rate, slightly larger, though I cannot express a final conclu-
sion with the limited material at hand. Moreover, our specimens indicate that
the post-nuptial moult begins while the boobies breed, and that the rectrices
are lost in alternation. In a January bird from Lobos de Tierra, the succession
of an old quill, a new quill, an old quill, is unbroken across the tail. Primaries
and secondaries were being replaced in opposite directions from the wrist.
At the Lobos Islands and elsewhere in northern Peru, as well as in Ecuador,
the Blue-footed Booby is known as the ‘‘Piquero,’’ a name reserved farther
southward for the Peruvian Booby (Sula variegata). In the south the Blue-
footed Booby is called ‘‘Camanay.’’ To southward of Lobos de Afuera, how-
ever, the species is relatively scarce and inconspicuous. This part of the coast
is, in fact, the boundary between the two species; a little to northward one
finds no examples of variegata and a little to southward nebouxii disappears. A
manuscript by Forbes, which I had the pleasure of reading at the headquarters
of the Guano Administration in Lima, states that Blue-footed Boobies formerly
nested in small numbers at the Guafiape Islands, south of Salaverry. They no
longer do so, although one may see a casual example among the thousands of
Sula variegata in the surrounding waters. If it is true that the Blue-footed Booby
occasionally reaches the Chilean coast, from where the type specimen is alleged
to have come, it probably attains such latitudes by way of the warmer waters
outside the zone of active upwelling in the Humboldt Current. Its occurrence
in Chile should certainly be regarded as accidental, and Hellmayr (1932) omits
it altogether from his recent list of the birds of that country.
Although reckoned the least important of the guano birds, the Blue-foot or
Camanay, through years of undisturbed breeding at Lobos de Tierra, has in-
creased enormously in numbers. The World War proved a boon to the species,
for the scarcity of suitable cargo vessels, and the high cost and uncertainties of
ocean freightage in general, long deterred the Peruvian Corporation, which
alone held the right to export guano, from conducting any excavations.
The Camanay is not a colonial bird, strictly speaking, but in many of the
flat, detritus-filled valleys of Lobos de Tierra its nests are now so thickly dis-
tributed that the total increment of guano is very large. It is hard beset by an
extraordinarily abundant enemy, the ‘‘Cleo’’ or Kelp Gull; but since it is the
boldest and most pugnacious of all the guano birds, it is well able to defend
itself successfully, and I doubt whether its increase is to be limited by any
other factors than the supply of food, space for reproduction, and the nature of
the consideration it may receive from human beings.
The Camanay is a slightly larger bird than its relative the Piquero or Peru-
vian Booby, from which it differs also in coloration, the head, throat and upper
breast being more or less overlaid with cinnamon-brown. Its large, webbed
feet are of an unbelievably bright blue color, which gives it an extremely bizarre,
almost grotesque, look. The females weigh about 1700 grams, and exceed the
males in size by one-fourth. More striking sexual differences are revealed by
the yellow eyes, which, in the female birds only, look as though they had
834 OCEANIC BIRDS OF SOUTH AMERICA
huge, somewhat star-shaped pupils, an effect probably produced by masses of
black pigment in the iris. Still more impressive is the dissimilarity of voice in
the two sexes, for while the males express their emotions by mild and plaintive
whistles, the utterances of the females are strident, raucous trumpetings. As
regards the voice, I found that the male Camanay is equipped with a double
sounding-box at the junction of the trachea and bronchial tubes. The throats
of the females, and of the young of both sexes, show no such structure, and this
observation led to the interesting discovery that the young males, as well as
their sisters, have the same resonant, ear-splitting call as the adult females.
The change in the voice of the males comes with ma-
turity, when the delicate vibrating membrane of the
vocal organ grows out to form a hard, egg-shaped
chamber, thus converting a trumpet into a whistle! The
same mechanism, or a similar one, appears to be present
in most members of the family Sulidae.
Lobos de Tierra supports a varied feathered popula-
tion, but far and away the dominant guano bird, and
one of the two most abundant birds of any kind, is the
Camanay. Its only rival in numbers is the Kelp Gull.
The Camanays, unlike the other guano birds, are not
truly colonial, and yet their nests are often very close
together. Sometimes, too, they are situated within a
meter, or even a handbreadth, of those of Piqueros or
of gulls. Looking in any direction over Lobos de
Tierra, from practically any spot on the island, one can
hardly fail to see thousands of irregularly distributed
y ©& Camanays, here in rather dense aggregations, there scat-
Dorsel ue _ tered thinly.
Hel Gol cEeaches and During my stay in January the breeding of the spe-
syrinx of Sula nebouxii, to Cies was in all stages. Fully grown, dark-breasted,
illustrate ontogenetic brown-eyed fledglings, which had left their nests and
changes correlated with parents, were common everywhere, especially near the
pax young bisdsof both eager's edge where they stood in flocks and exercised
sexes have the structure, 3 : : : aus
and the trumpet-like their wings by violent flapping. The guano administra-
voice, of theadult female. tion warden called these ‘‘primeros,’’ or first- brood
young, and stated that the eggs from which they had
hatched had been laid during October. Then there were sedentary downy
chicks of various ages, of which the younger examples were scarcely distin-
guishable from the nestling Piqueros. Sets of three eggs, more or less incu-
bated, were in many of the Camanay nests, and sets of two or only one egg
were no less numerous. Finally, a large proportion of adult Canianays were
love-making on their proposed nesting sites, so that a great many eggs were
apparently still to be laid.
Beebe has stated that at the Galapagos the Blue-footed Boobies lay no more
than one or two eggs, in which peculiarity he sees a possible ecological relation
BLUE-FOOTED: BOOBY 835
with the absence of predatory enemies such as vultures and Kelp Gulls. At
these islands as in northern Peru, the brooding of the eggs is more a matter of
keeping them cool than of keeping them warm. Consequently, the birds stand
for hours above their eggs, not touching them but creating a shadow to shut
off the fairly coddling rays of the equatorial sun. The incubating adults them-
selves often pant as if in distress from the heat, and the chicks likewise suffer,
particularly when the shafts of their developing quills are weighted down to
the hot ground with the abundant blood they contain. Young chicks must be
constantly shaded for, even if they were not roasted alive, prolonged exposure
would make them unwilling or unable to accept food, as is also true of many
passerine birds (Willford, 1925, 293).
Beck (1904, 7.) has written of the broiling and insufferable ancient crater at
Daphne Island, Galapagos, in which the Blue-footed Booby is the only resident
bird. Its walls are so high and steep that the boobies have to circle before they
can fly over the rim. Many skeletons tell of the heavy mortality among them.
At certain other islands of the Galapagos, however, this species nests on ridges
or ledges 300 meters above sea level, which indicates a remarkably wide toler-
ation of nesting conditions.
Because of the character of its nesting, because it is the least susceptible to
disturbance of any of the Peruvian guano birds, and because it goes right ahead
with all the actions of its normal life in the presence of a human observer, the
Camanay is by far the most entertaining of the sea birds inhabiting the Lobos
Islands. It is curiously stupid in some ways, for, while it insists upon laying
its egg beside your doorstep or in the middle of a frequented path, it never ceases
to resent the passage of men or dogs, and will scold just as angrily the twentieth
time in a single day as the first. The trail leading from Caleta de Cherra to the
lighthouse of Lobos de Tierra, for instance, was traversed many times daily by
a considerable number of persons, and yet the Camanays, which had planted
their families from one end to the other of the well-trampled ground, threatened
with unabated ardor whenever they had to share its use with men.
The courting of the Camanays is extremely diverting and, so long as a
beholder does not come unreasonably near them, the birds have no objection
to being watched. I have frequently witnessed the performance from a distance
of three paces. They begin their advances very early in the morning and con-
tinue, judging from vocal indications, well into the darkness of night. Nothing
could be more comical than the manner in which the male, with his tail cocked
up like a wren’s, goose-steps and waddles about, raising his bright blue feet as
high as possible and thrusting forth his chest. After strutting round and round
in this way for a few moments, he will turn toward the female, who may be
several meters away, and, bending forward and raising his wings, he will utter
a most beseeching little whistle. This may be repeated several times before he
begins to strut again. Then he may pick up a feather, shake it so rapidly that
his whole head appears as a blur, and finally lay it gingerly on the ground,
which is perhaps his method of suggesting a location for the nest. I often saw
several males behaving in this way before one female, especially in early morn-
836 OCEANIC BIRDS OF SOUTH AMERICA
ing, the lady usually assuming an air of utter indifference. Sometimes the suitors
would ‘‘mark time’’ for considerable periods, rhythmically lifting their feet
and putting them down again in the same spot.
During later stages of courtship, doubtless after actual pairing, the female
becomes more demonstrative, frequently touching the bill or the neck of her
spouse, and sometimes even raising her wings in response to his salutation.
At all times, however, the males perform much more often than the females.
Some time before the first egg is laid, the nest itself becomes visible as a slightly
rubbed spot on the soil, and after this both birds stand close by the site until
incubation begins.
The Camanays form no high ring of guano around their nests, as the Piqueros
do. The accumulation seems to be relatively slow, old nests being encircled
only by a broad, flat, whitish frosting. Although the guano contribution of
the species is, therefore, not spectacular, it assumes considerable importance
when the birds are left undisturbed for long periods of years, as they have been
recently. In the presumably optimum environment of the Lobos Islands their
mortality appears to be slight, certainly less in proportion to numbers than
that of the other species. The dried carcasses of young Camanays were nowhere
numerous at the date of my visit, whereas the Lobos pelican colonies of former
seasons were strewn with chicks which had failed to survive in the merciless
struggle for existence.
I did not learn the length of time that elapses between deposition of the
several eggs, but I noted that the chicks in one nest usually showed considerable
discrepancy in size and development. Three eggs constitute the maximum set,
although, among the families of well-grown chicks, two is a commoner number
than three, but this may be due to the loss or sterility of one egg. Both sexes
incubate and brood the young, and when one of a pair returns from sea to re-
lieve its mate, the birds usually spend a long period in demonstrations of affec-
tion before one steps off the nest and the other promptly covers it. I most
frequently saw this change taking place during the middle of the day, and I
observed birds of both sexes incubating at all hours.
The arch enemy of the Camanay is the equally abundant Cleo, which is
quick to swoop down upon exposed eggs or featherless chicks. Within two
steps of me I have seen the gulls pick up Camanay eggs and fly off with them.
It should be noted here that the sitting Camanays abandon one egg much more
readily than they do two or three, and that they can scarcely be driven from the
nests after their chicks have hatched. At least one parent is constantly with
the youngsters until the latter have practically passed out of the downy stage.
Rarely the adults will attack the Cleos on the ground and boldly defend their
offspring, but, while they are individually more than a match for the enemy,
they are almost always losers, for Cleos in the rear will steal] their nestlings
while they are defending them in front. The obvious bewilderment of a pair of
Camanays which stand gazing into a robbed and empty nest is altogether pa-
thetic. On the western shore of Lobos de Tierra I once flushed a bird which
had been sitting not upon eggs but upon two beach-worn snail shells, and I
BLU EFOO TED: BOO BY 837
wondered whether the parents had pushed such unpromising nest-eggs into
their hollow after the breaking up of their home by the gulls.
It is chiefly upon the pretty, innocent-looking, downy chicks of the Cleos
that the Camanays wreak revenge for all their wrongs. From the day they
hatch, the young gulls are accustomed to leave their seaweed nests at the fancied
approach of danger, when, with complete ingenuousness, they will walk
directly among the brooding Camanays, and even try to snuggle beneath them.
Alas! The Camanays know the foe even in the mottled down of babyhood, and
the young Cleos are stabbed through the head or body by rapier bills. While
the poor victim cries out in terror, the furious Camanay may thrust a saw-
edged beak into its open mouth and out through the back of its skull. More
than once I have seen young gulls so impaled by the lower mandible of a
Camanay that the latter had to shake its bill violently in order to get rid of
the burden. At such tragic times the screaming adult Cleos descend from the
swarm above as if to defend the helpless chick, though an exposed egg will
even then tempt them into forgetting what they had started about. On at least
two occasions I saw Camanays which were not occupying nests go out of their
way to attack young gulls that were running over the rocks. The results were
lively but very unintelligent fracases, in which many birds of both species took
part and in which only the unfortunate eggs and chicks of either suffered serious
damage.
The Turkey Vulture is also an enemy of the Camanay, though far less to be
feared than the Cleo. That the Camanays recognize it as objectionable is clear,
nevertheless. One day I flushed a fledgling vulture so that it launched off from
a high ledge upon what may have been its first flight. To my surprise it was at
once attacked in the air by Camanays, and knocked down to earth. I never
saw the boobies molest an adult vulture.
When a Camanay sitting upon eggs is approached, its ‘hair stands on end”’
all over, particularly on the lower part of the back where the feathers turn
forward into a retrorse position. At the same time the plumage of the head
and neck bristles like porcupine quills. Next, the bird begins to protest by
whistles or trumpetings, according to its sex, and by striking out with its
formidable bill. If it be a bird with well-grown young it will come between
them and the intruder and express intense rage, spreading its wings like a bittern
and threatening with its wild eye and darting weapon. When both birds of a
pair assume this position the scene is most striking. The powder-puff young-
sters, likewise wielding ready and effective beaks, stand as a rear guard, all the
while swearing in a raucous voice inherited from their savage mother.
Young Camanays, like the chicks of the other guano birds, are persistent in
begging to be fed, and the heads of a whole nestful sometimes disappear down
the parent’s gullet as they seek their half-digested luncheon. The adults dis-
gorge, when excited, much less freely than their relatives, the Piqueros. One
incubating bird, however, was observed to eject from its crop and throat a
herring 25 centimeters in length. In general, I believe, it preys upon relatively
large fishes, rather than upon anchovies and silversides.
838 OCEANIC BIRDS OF SOUTH AMERICA
In its feeding habits the Camanay is given much more than the Peruvian
Booby to frequenting shallow coves, in which it makes cautious, slanting dives,
besides which it swims more or less upon the surface. Farther out at sea, how-
ever, I have seen it making long straight plunges with very nearly as much
verve as the Piquero. Verrill (1923, 303) reports that at Paita he has seen one
dive “‘from a height of fifty feet into water less than two feet deep."’ My
colleague, Mr. Jaques, was impressed by the smoothness and lack of splash with
which this species enters the water, in which feat it excels all other diving
birds known to him. The most detailed and circumstantial description of its
plunging is that vividly set down by Delano (1817, 380) at the Galapagos:
. These birds collect together in small flocks for the purpose of diving. They fly round in
a circle and continue to rise till they get to the height of from sixty to a hundred yards in the air,
when one of them makes a pitch to dive, at which motion every one follows, and they fly down
with remarkable swiftness, till within four or five yards of the surface, and then suddenly clasp
their wings together and go into the water with the greatest velocity that can be conceived of,
exceeding any thing of the kind that I ever witnessed. This bird should be contrasted with the
pelican. I have often stood upon the ship's taferel rail, and sometimes have gone into one of the
tops, to observe the motions of these birds whilst they were diving, especially when they came
near the ship. They go into the water with such force as to forma curve of thirty or forty yards in
length, before coming to the top again, going to a great depth under water. They glide under
water at almost as great a degree of swiftness as when flying in the air. The water was so very
transparent where the ship lay, that they could very plainly be seen when near, during all their
submarine course.
PIQUERO
Sula variegata
Dysporus variegatus Tschudi, 1845, Fauna Per., Orn., p- 313 (coast of Peru).
Names: Peruvian or Variegated Booby. In the extreme north of Peru it is called “‘Camanay,”’
the name ‘‘Piquero"’ in this region being reserved for the Blue-footed Booby. No other specific
name than variegata seems to have been applied to this species, except in error or in accounts of
sub-fossil remains. Skulls from northern Chile have been described under the name antigua.
Characters: A white-headed and white-bodied booby, with variegated white and brown
wings and back.
Adults (sexes alike): Head, neck, and ventral surface white; quills of wing and their coverts
generally brown, but lighter basally, the primaries fuscous black at least on their outer webs,
the secondaries, longer scapulars, and primary coverts fuscous, with whitish bases and with slight
white terminations or borders on the outer webs; rectrices mainly whitish, the central feathers
wholly so, the lateral feathers progressively darker, becoming fuscous black at least on the outer
webs of the most lateral pair of quills; feathers of entire mantle, including the lesser coverts of the
wings, fuscous, with broad white distal margins which tend to disappear with wear, thus causing
the back to become progressively browner; lower back, rump, flanks, upper tail coverts, thighs,
and lining of wing similarly mottled with brown white-edged feathers. Iris ruby-red; bill purplish
blue, sometimes almost pinkish, with the distal part horn-colored; legs and feet bluish gray,
darkening in dried skins almost to blackish. Many museum specimens show bills which are dis-
tinctly red. This color does not appear in life and may be due to dried blood in the capillaries.
14 males from the coasts of Peru and Chile, between Lobos de Tierra Island and Chiloé Island:
wing, 361-394 (379.5); tail, 146-181 (163.5); exposed culmen, 88-99.6 (92.6); length of gonys,
24-31; tarsus, 45-50 (48); middle toe and claw, 70-82 (78) mm.
9 females: wing, 378-415 (395.4); tail, 161.5-190 (172.5); exposed culmen, 96-101 (98.2);
tarsus, 48-53 (50.4); middle toe and claw, 77-86 (81) mm.
The moult of the quills progresses during incubation, the new remiges and rectrices being much
PIQUERO 839
darker than those of worn plumage. Wear and fading likewise produce marked contrasts in the
dorsal plumage of birds observed in life, some adults appearing fuscous brown, while others are
almost gray. The pecten of the claw on the middle toe is often filled with down and small feathers,
showing the use of this organ in scratching and preening.
In immature plumage the white areas throughout have a buffy or dingy appearance, owing to
the presence on each feather of a large subterminal brownish gray patch. Furthermore, the white
borders of the dorsal plumage are much narrower than in adults, giving young birds a substantially
darker cast. The young have a yellowish gray iris, which darkens with age to brown before it
turns red; the bill, legs and feet are slightly blue. Primaries, secondaries, tertials, greater and
middle coverts, scapulars, and tail feathers appear before the downy nestlings are of full size.
Specimens with the breast and belly fully feathered, and the upper tail coverts and back feathers
appearing, show adult measurements. The feathers of the breast and belly in such juvenal plumage
are of light fuscous or gray, widely margined with white. The feathers of the shoulders are dark
fuscous, scarcely tipped with white, and a band of similar feathers extends to the breast around the
base of the still down-covered neck. The upper surface of the wings is as in the adult, except that
the colors, as everywhere on the body, are duller. A conspicuous feature of the immature bird is
the cross of white down on the rump, which persists long after the rest of the body has become
fully feathered. The predominant white plumage of the adult bird is not evident until a later stage.
The young in the field are, indeed, easily to be confused with those of the somewhat larger species,
Sula nebouxii (Coker, 1919, 466).
The eggs number from one to four. Out of 25 nests which Coker counted at one view, 9 con-
tained 3 eggs. They are inclined to be somewhat pointed and are generally rather uniform in size.
The color is a pale blue, smeared more or less with a white chalky coat. The extremes among a
series from Lobos de Afuera and the Chincha Islands measure 53 x 40, 62 x 44, and 59 x 39.5 mm.
Distribution: The cool upwelling zone of the Humboldt Current, along the shores of Peru and
northern Chile. Breeding from the neighborhood of Point Parifias to Arica or southward. The
breeding station most distant from the continental coast is at the Hormigas de Afuera Islets, west
of Callao. Coastwise, beyond the breeding grounds, birds of this species range sporadically north-
ward as far as the Gulf of Guayaquil, and occasionally, or perhaps regularly, southward as far as
Chiloé Island. (Repeatedly, but erroneously, recorded from the Galapagos Archipelago.)
‘‘Piquero”’ is the Spanish word for lancer, an appropriate appellation for
this booby, the spectacular plunges of which are familiar sights throughout
the length of the Humboldt Current. It is thrilling to see one bird descend
straight from the blue and vanish in a jet of foam which seems to leap to meet
it, so swift is the fall. But a Piquero is rarely alone, and the scene of thousands
striking the ocean like hissing hailstones is one that beggars description.
Perhaps the most vivid of my memories concerned with the Piquero dates
from December 7, 1924, when, as the setting sun illumined the weathered
flanks of the Cerro de Guafiape, south of Salaverry, a vast flock followed its
prey to a point abreast of the steamer upon which my family and I were voyag-
ing. The long-drawn-out horde of birds was moving southward at a pace which
kept its middle just abeam. The white bodies caught the late rays so that each
bird looked like a glowing spark. A continual shower fell from the array to
the water, some of the Piqueros coming down aslant while others tilted up their
tails and dropped like stones. The whole darkening sea became a field of small
explosions.
This white-bodied booby, with its speckled back, will offer no difficulty of
identification, for it is far and away the most abundant bird of its region, which
means the strictly littoral waters along the desert coasts of Peru and Chile.
840 OCEANIC BIRDS OF SOUTH AMERICA
To northward and southward there are never more than a few strays. I saw a
lone bird off the south end of Puna Island, Ecuador, on February 26, 1925, and
Paessler (1914, 277) records one as far north as Manta in November. At times
of the pest that follows an exceptional southward flow of El Nifio, sick Piqueros
may enter the Gulf of Guayaquil in moderate numbers, and wash ashore, dead
or dying, along the beaches of Chanduy.
To southward of the desert shores, Piqueros likewise wander casually, and
during the Brewster-Sanford Expedition Beck saw a few off Anctd, Chiloé
Island, fishing outside the mouth of the river or perching on small islets with
the native shags. This was in April, May, and June, and Bullock’s notes state
that the species is a common visitor to the waters about Mocha Island at the
same time of year. From more northerly parts of Chile, the Piqueros are re-
ported everywhere, sometimes in abundance equal to that along the Peruvian
coast, but I have been unable to run down a single satisfactory breeding record
from any point to southward of the frontier between Peru and Chile. Offshore
the species finds its most distant nesting station at the islets of Hormigas de
Afuera, which puts it in the same category of Humboldt Current endemics as
the Guanay, the Inca Tern, and Belcher’s Gull.
The northernmost breeding station of which I know is on cliffs outside the
sea caves at Capullana Point, near Talara. A few Piqueros nest in similar situ-
ations close to the mouth of the Quebrada Parifias, at the westernmost tip of
the continent, although the greater part of the booby population in the neigh-
boring waters is made up, of course, of the Blue-footed species (Sula nebouxit).
The most southerly nests of the Piquero encountered during my own field work
were observed at San Gallan Island in November, 1919, but Mr. Jaques reports
a few at Santa Rosa Island, Independencia Bay. It is highly probable that other
breeding stations will ultimately be discovered southward to such islands as
Alacran, off northern Chile.
Numerous references in the literature include the Peruvian Booby within
the avifauna of the Galapagos Islands. These all prove to be erroneous, how-
ever, and to be based upon misidentification of the Masked Booby (Sula
dactylatra).
As soon as a southbound ship on the west coast of South America leaves
Lobos de Afuera astern, it will be forced upon the attention of even a casual
observer that one booby over the ocean roundabout becomes rapidly replaced
by another—in other words, the warm-water realm of the Blue-foot or Camanay
is succeeded by the cool-water realm of the snowy Piquero. The latter is a
swifter, more active flyer, and appears to be a more powerful diver, than its
northern relative. In these facts, perhaps, lies at least a partial explanation of
the distributional limits, for it may well be that the Camanays cannot success-
fully compete as fishermen with the wonderfully specialized and multitudinous
Piqueros, which form an inseparable element of bird life of the Humboldt
Current.
The Piquero is the most abundant of the guano birds, and, as a producer of
available fertilizer, it has undoubtedly won the place of closest rival of the
PIQUERO | 841
Peruvian Cormorant or Guanay. It is in all ways a less sensitive and more
adaptable bird than the native pelican, and in future the relative standing of
the two is likely to swing more and more in favor of the booby. A single
Piquero produces as much as 150 grams of guano a day. If 30 grams of this (a
low estimate) were deposited on an island, a thousand Piqueros would produce
more than ten available metric tons a year, or a million birds 10,000 tons,
which might be close to a million dollars’ worth.
The Piqueros are the noisiest as well as the most numerous of the guano
birds at the Peruvian islands, and on a quiet morning their voices come as a
loud chorus, a medley of whistles, gabblings, and trumpet-like calls ringing
out from each community. The birds nest mostly upon the cliffs and pinnacles
of the islands but, with the recent reduction in the pelican population, they
have taken to spreading over the flat surfaces or pampas. Curiously enough,
early observers have recorded that formerly these boobies nested habitually in
the central parts of the islands, whereas modern visitors have found them to
be typically, or almost exclusively, cliff-dwelling birds, and their reinvasion of
the insular table-lands is certainly a very recent development. Coker (1935, 11)
discusses this matter as follows:
That careful student of natural history, Dr. J. J. von Tschudi, who spent four years in Peru
just before the modern commercial extraction of guano began, said that the variegated gannet,
Sula variegata Tschudi, was the chief guano-producing bird, that it nested only on the barren islands
and not on the mainland and that it made nests in the sand, implying that it had extensive rookeries
on the level parts of the islands. Not one of these statements was applicable in 1907 and 1908. The
gannets of this species nested almost exclusively on the faces of steep cliffs, its nesting areas only
rarely overflowing to a very slight extent onto ground on which a man could find a fair foothold.
The geographer, Raimondi, in 1856, a few years after guano extraction had begun, confirmed Tschudi
by stating that the Sulas ‘‘keep themselves in the interior of the islands’’ (translation). Some years
later he uses a more qualified expression—they cover at times a part of the islands (‘‘cubren a veces
la parte de las islas’’). Could yon Tschudi and Raimondi have been mistaken, or had this bird
changed its nesting habit with the development of the guano industry during the latter half of
the nineteenth century?
Now it happened that about ten years after the new plan of conservation had come into effect,
Dr. Murphy: visited some of the same islands on which my observations were made and took
photographs showing great rookeries of this species on the level or gently sloping ground—just
the condition that von Tschudi and Raimondi had encountered on the islands. Such a photograph
as Murphy shows opposite page 304 could not possibly have been taken in 1908. The statement is
not lightly made. I saw hundreds of rookeries of this species on islands and mainland over some
700 miles of the coastal region during a period of a year and a half and made many inquiries with
the particular aim of checking the statements of von Tschudi and Raimondi. The conclusion seems
inescapable that Sula variegata did originally nest extensively on level ground (and doubtless also
on the cliffs), that some time during the period of unregulated extraction of guano, it gave up
practically entirely the level areas, and, seemingly, found previously unfrequented cliffs on the
mainland, and that it subsequently reclaimed the level areas when conditions made it feasible to do so.
I noticed the interesting fact that Piqueros nesting upon level ground are
shyer and more susceptible to fright than those occupying the usual environ-
ment of the cliffs. Birds in the latter situation will permit observation at very
close range, while those on flat ground are liable to abandon their nests at the
approach of an intruder. Piqueros on the pampa are also more or less at the
842 , OCEANIC: BIRDS OF SOUTH AMERICA
mercy of the pelicans, which clumsily trample their eggs and young, as I have
already described. It may therefore prove to be true that cyclic fluctuations in
the relative abundance of pelicans and boobies have something to do with the
nesting habits of the latter, and that in times of their ascendancy the Piqueros
simply ‘‘overflow’’ from the filled precipices to the partly empty tops of the
islands.
In 1919-1920 I found Piqueros breeding upon nearly all the Peruvian islands
visited, though in very small numbers to the southward of the Ballestas group.
Eggs and young in every stage of development were observed at each island, and
on many mainland cliffs, between Talara and San Gallan. Coker (1919, 467)
found the breeding season to be continuous throughout the year, but in most
colonies a large proportion of the eggs are laid between September and Febru-
ary, indicating a certain heightening of reproductive activity during the
southern-hemisphere spring.
At Lobos de Tierra, in January, 1920, the Piquero was far less numerous
than its rival, Sula nebouxii. I found, nevertheless, seven Piquero colonies, all
located on flat ground. The appearance of these, as viewed from adjacent hill-
tops, was strangely unlike the precipitous eyries with which I had already
learned to associate the species. A little to southward, at Lobos de Afuera, the
two boobies had struck an approximately even balance in numbers. Further-
more, the behavior of the Piqueros seemed more “‘normal’’ for, in the absence
of extensive cliffs, they were occupying chinks in the piles of sand and rubble
which had passed through the guano screens during earlier exploitation.
South of the Lobos Islands, the Camanay was out of the picture, and the
Piquero ruled alone. At the Guafiape group it was more numerous than any-
where else, the south island being occupied all but exclusively by this single
species. The leeward slope of North Guafiape, from which 7640 tons of guano
had just been taken, was bereft of birds of any sort. The entire windward side,
however, with the exception of a few sandy banks, was packed with breeding
Piqueros and Guanays. The former covered not only the steepest hillsides, but
nearly all of the peaks as well. From a distance, the territory of the Guanays
looked black, that of the Piqueros gray. These mutually exclusive areas dove-
tailed with one another, so that the distribution of the two species was revealed
clearly from afar. On the heights of South Guafiape not one Guanay was living
and, except for the narrow domain of Inca Terns and Red-footed Cormorants
around the weedy rocks at sea level, it was inhabited only by the Piquero. The
breeding ground spread from the magnificent western scarp, 125 meters high,
over to the pampa of the eastern slope, where the nests filled extensive spaces,
presenting one of the most beautiful scenes that could be imagined. Evidently
the higher sites were the preferred ones, for on New Year's Day fresh eggs were
to be found only on the lower slopes, as if they had been laid by late-comers.
The thickly peopled summit, on the other hand, had countless thousands of
well-grown chicks. The older fledglings among these were winnowing the
air with their long wings and thus getting the exercise which is a necessary
preliminary to flight.
PIQUERO 843
Still older chicks, which had left the vicinity of their nests, were encountered
all over the island, resting or sleeping, striving to scramble uphill, or launch-
ing out into space. Sometimes they would hover or wabble in the air for a
minute or two at a time. One could never tell when such a youngster might
come hurtling down from aloft, to alight with a thud close by. These fledglings
were all extraordinarily tame; almost any of them could be touched or picked
up. During the greater part of the afternoon five of the guano workers fished
from a rock upon which two of the young Piqueros were standing. The surface
was not more than three paces square and the fishermen, who were continually
moving about while cutting bait or landing their catches, would stoop now
and then to give the entirely undisturbed *’Piqueritos’’ a pat on the head or a
playful chuck under the chin.
I have seen the penguin regiments of the far south, the courtship antics of
the Wandering Albatross, a file of eighteen condors which passed me within a
stone’s toss, and other marvelous sights in which birds held the center of the
stage, but nothing more exquisite than the pantomime of adult Piqueros hang-
ing on the wind above the cliff of Guafiape. The innumerable white birds would
come sailing up over the nests on the plateau and, when they had reached the
brink, the updraft would lift them like kites. Then for minutes they would
poise, hardly changing their positions, but twisting their necks to look toward
me or to glance at their hopeful chicks below. Some of the graceful, living
seaplanes were hardly more than arm's reach from me, and beyond they stretched
away until the distant birds seemed like a flurry of snowflakes.
At Mazorca Island, of the Huaura group, Beck found plenty of young and a
few eggs of the Piquero on June 14, 1913. My visit, on December 29, 1919,
came at a higher peak of the breeding season, for the great majority of the
many thousands of nests contained eggs or callow chicks. The latter are pinkish
when they hatch, but rapidly turn livid or purplish, presumably under the oxi-
dizing action of light. At Mazorca the main headquarters of the boobies were
on cliffs at either end of the island, but from here they swelled over on to the
pampa, and interdigitated with a great colony of cormorants. A few of the
Piqueros even had nests on top of boulders in the heart of Guanay territory.
Love-making was very active at Mazorca. Although the sexes are of different
size, it is somewhat difficult to distinguish them by appearance alone. The
voices, however, are revealing and, although I neglected to examine the syrinx
of this species, it probably shows the same structure and peculiarities as those
described in the life histories of the Blue-footed and Masked Boobies. At any
rate, one of each pair of Piqueros has a high-pitched whistling note, while the
other (presumably the female) gives utterance to a harsh chatter, with an
occasional single trumpet-call. Since the members of a family converse almost
uninterruptedly, the difference is very marked. They shake their heads violently
and half spread their wings before each other. Their throats tremble in the
characteristic steganopode manner. Both sexes incubate and, at the time I was
watching them at Mazorca, as many males as females were sitting on eggs.
A long-range hail usually foretold the return of a mate for nest relief. As soon
844 OCEANIC BIRDS OF SOUTH AMERICA
as the newcomer arrived, there would be a crossing of necks and other demon-
strations of affection, often accompanied by an incidental territorial quarrel
between one of the happy birds and a disgruntled neighbor.
At the Pescadores, Asia, and Chincha Islands, the Piqueros were only moder-
ately common during the time of my visits, and they were confined entirely to
the cliffs and ledges, or to the very edge of the plateaus where there is always a
narrow ribbon of territory avoided alike by cormorants and pelicans. At Asia
it was evident that the Piqueros react favorably to sunlight, for they had kept
out of the perpetually shadowed parts of a great chasm, their nests forming a
sort of sundial line along a stretch of the wall reached daily by late afternoon
rays.
At the Chinchas, where I remained for a month, there was opportunity to
watch selected families throughout a good part of the breeding cycle. In mid-
November some nests held one new egg, some chicks about to fly, while others
represented every intermediate stage of family development. Three eggs in a
set seemed to be as common as two and, unlike the rule in the life history of the
Brown and Masked Boobies, no lethal penalty was necessarily paid by the second
or even the third offspring. Three fledgling chicks, in fact, were not uncommon
in a nest, and two were exceedingly numerous. Is it not likely that a correlation
exists between this condition and the ready availability of plenteous food in
Humboldt Current waters? The tropical “‘blue-water’’ boobies which produce
two or three eggs are living, so to speak, beyond their means, for they find
their food in relatively poor pastures, and must fly far in their daily foraging.
The penalty for this has been the development of a ‘‘Malthusian’’ mechanism
leading to the suppression of all but one chick in each generation. The prolific
Piqueros, on the contrary, have the richest and least variable of food resources
at their front doors through all the year.
That the eggs in a set are deposited at intervals of several days is indicated
by the sequence of sizes in a nestful of chicks. Not infrequently one may be
twice as large as its nestmate, yet both such usually survive. They seem to be
rather chummy companions, often stroking or nibbling each other, while mak-
ing soft grunting sounds. When the parents return, well laden, a considerable
stimulation of coaxing seems to be necessary before food is relinquished. The
heads of the youngsters then disappear down the gullet of the old bird. Replete
chicks are likely to sleep for a while on their sides, curled up like kittens, with
the bill tucked under the wing. The return to consciousness and renewed appe-
tite is accompanied by prolonged yawning. The older chicks are well able to
defend themselves by biting, although they seem less ferocious than the fledgling
Camanays and boobies of certain other species. Excitement always sets their
pouches atrembling, which reminds one of their ordinal relationship with
cormorants and pelicans, both of which exhibit the same trait.
The last thought recalls a curious custom of the adult Piqueros, namely, the
persistence with which they associate with groups of other Pelecaniform birds
in flight. Wedges of Guanays and files of pelicans in the Humboldt Current are
generally, if not invariably, accompanied by, or even led by, a lone Piquero.
PIQUERO 845
Large formations often have a Piquero here and there along the outskirts, as
though a self-appointed booby lieutenant were an essential part of any successful
foray against the fish!
When feeding, the Piqueros generally begin by circling over the water where
they see, or suspect the presence of, their prey. Then they suddenly tip up and
fall, sometimes with almost complete synchrony. Between the Guafiape
Islands I once watched them dropping like plummets all over the strait, closing
their wings the instant before striking the water. So rapidly did they descend
that they were visible only as white streaks followed by splashes. Guanays,
““Chuitas’’ or Red-footed Cormorants, and penguins were fishing among them,
and I marveled that some of the surface-feeding birds were not transfixed by
the winged arrows which fell all about them. They may remain under water
at least as long as a minute, after which they reappear at the surface to swallow
their catch before rising to repeat the performance. As Coker (1919, 466)
remarks, they may dive from a height that seems to be 30 meters, with wings
held slightly open to direct the headlong course, or from a tenth of that altitude,
or from a position barely above the surface from which they have just risen.
The technique depends, no doubt, upon the depth of the schooling fish. Coker
thus describes a scene he witnessed in the Bay of Pisco:
We saw an actual cloud of thousands of piqueros flying over a school of anchobetas, when
suddenly they began to fall, hundreds at a time until practically the whole cloud was precipitated
into the sea before the first birds had risen from their brief rest after emerging from beneath the
surface. Scarcely a bird was seen in the air. The first to fall were soon up, however, and from that
time on the plunges were uninterrupted. Changing the course of our boat a little we soon rowed
directly through this downpour of birds. Hundreds of birds seemed to strike the water at every
instant, and even within a few feet of our boat. The bewildering effect is to be imagined rather
than described; the atmosphere ‘‘cloudy’’ with birds; the surface of the sea broken and spattering
from falls of animate drops and speckled with reappearing birds; the confused sounds of whirring
wings and unremitting splashes.
In the Humboldt Current are various kinds of small fishes that travel in
enormous shoals. These include silversides (Atherinidae) and several sorts of
herrings, all of which are doubtless acceptable to the Piquero. Coker states
that the birds also regale themselves at times upon Mdanida and other small
crustaceans. The only food I actually identified in Piquero stomachs, however,
was the native anchovy (Engraulis ringens), and this creature is probably the
mainstay of the booby’s existence. In three stomachs sent to the United States
Biological Survey, two were more or less filled with anchovies, while the third
contained a dozen of their eye-lenses.
The hazards of the Piquero’s life are related chiefly to the nature of its pre-
ferred nesting sites. Chicks fall out of the precariously perched nests or, more
likely, a certain proportion of the nests themselves give way and crash to rock
or water. At any rate, the foamy drift lines that stretch to leeward—z. e.
usually northward—of the Peruvian islands are likely to be well punctuated
with the corpses of nestling Piqueros of all ages. The adults have for the
most part to encounter only the never-ending but unconscious competition with
other kinds of guano birds along the border lines of terrains suitable for one or
1
846 OCEANIC BIRDS OF SOUTH AMERICA
the other. A more direct and active enemy is the Chilean Skua which, according
to Beck’s field notes, victimizes the Piqueros to a certain extent by forcing
them to disgorge in flight.
MASKED BOOBY
Sula dactylatra
Sula dactylatra Lesson, 1831, Traité d’Orn., livr. 8, p. 601 (Ascension Island).
Within the field of this book there are two well-marked subspecies of the Masked Booby, one
belonging to the tropical Atlantic, the other to the eastern tropical and sub-tropical Pacific. The
differences between them pertain to size, rather than to alleged distinctions in the skin-color of
face, beak, and legs. The Atlantic form should be known as Sula dactylatra dactylatra Lesson.
To birds of the eastern Pacific at least two names have been applied, as follows:
Sula granti Rothschild, 1902, Bull. Brit. Orn. Club, 13, p. 7 (Culpepper Island, Galapagos).
Sula dactylatra californica Rothschild, 1915, Bull. Brit. Orn. Club, 35, p. 43 (San Benedicto Island, Revilla
Gigedo group). '
So far as I can determine from the material at hand, the Masked Boobies of the Revilla Gigedos,
the Galapagos, the coasts of Ecuador and northern Peru, and the Chilean islands of San Felix and
San Ambrosio all represent one race, which should therefore be known as Sula dactylatra granti
Rothschild.
Names: Blue-faced Booby, White Booby, *’Piquero Blanco.’ The commonest synonym of the
specific name is cyanops. Other synonyms include personata, nigrodactyla, elegans, and melanops,
while a considerable number of subspecific names have been given to representatives throughout
the world.
Characters: Largest of the boobies. The adult plumage is white except for the dark brown of
the wing quills and some of their coverts, the tips of the long scapular feathers, and the tail.
Adults (sexes alike except as regards size and flesh colors): Pure white except the quills of the
wing and upper coverts, and the tail quills, which are blackish brown, becoming fuscous or almost
chocolate-brown on the exposed outer webs of the wing coverts; the inner webs of the primaries
tend to become somewhat grayish, while those of the secondaries are basally white; the concealed
bases and middle parts of the rectrices likewise tend to become grayish or whitish, while the shafts
and bases of the central pair are conspicuously white. Iris yellow; skin of face black; bill distally
horn-color, bright orange-yellow at the base in males, and pink or light red in females; feet and
legs olive-drab in males, plumbeous in females.
Measurements of Sula dactylatra dactylatra:
9 males from Ascension and Fernando Noronha: wing, 406-433 (424); tail, 153-173.2 (166);
exposed culmen, 92.6-97.2 (95.6); tarsus, 53-56.2 (54); middle toe and claw, 84.6-88.6 (86.4) mm.
7 females from Ascension, Fernando Noronha, and Rocas Reef: wing, 417-440 (429); tail,
151.3-180 (164.6); exposed culmen, 91.6-99 (95.7); tarsus, 52-54.6 (53.4); middle toe and claw,
82.6-89.7 (87.3) mm.
Length, males, 80-82 cm.; females, 76-84 cm. Wing-spread, males, 155-167 cm.; females,
157-168 cm.
Measurements of Sula dactylatra granti:
5 males from the Galapagos: wing, 413-443 (429); tail, 172-181 (177.6); exposed culmen,
102-104.4 (102.7); tarsus, 52.3-58 (55); middle toe and claw, 90-93.5 (90.8) mm.
6 females: wing, 427-468 (450); tail, 176-189 (183); exposed culmen, 102-114.5 (106.5);
tarsus, 54-59 (57); middle toe and claw, 92-103 (96.1) mm.
The above were taken at sea off the Galapagos, and at the islands of Culpepper, Hood, Wenman,
and Daphne.
3 males from La Plata Island, Ecuador, and off Talara, Peru: wing, 439-457 (451); tail, 180-
196 (186.3); exposed culmen, 101-103 (102); tarsus, 54; middle toe and claw, 93-95 (94.3) mm.
2 females from La Plata Island: wing, 465-474 (469.5); tail, 188-193 (190.5); exposed culmen,
109-111 (110); tarsus, 55-56 (55.5); middle toe and claw, 99-103 (101) mm.
MASKED BOOBY 847
A male collected off Talara, Peru, January 20, 1925, weighed 2155 grams, and had a total wing-
spread of 168 cm.
4 females from San Felix Island: wing, 453-486 (471); tail, 188-196 (192); exposed culmen,
100.5-108.4 (104.1); tarsus, 57.4-60.6 (58.7); middle toe and claw, 92.4-103.5 (98.6) mm.
The size distinction between the Atlantic and Pacific races is brought out well by the following
average dimensions of females, the larger sex:
, ; Exposed Middle toe
Wing Tail eas Tarsus Ddeine
S. d. dactylatra
7° from Ascension, Fernando No-
ronha, and Rocas Reef. .... . 429 164.6 95.7 53.4 87.3 mm.
S. d. granti
129 from the Galapagos, La Plata
Island, and San Felix Island .. . 464 189 107 | 57.1 98.6
Immature birds have the head, neck, and upper parts smoky brown, somewhat mixed with
white feathers. Between the base of the neck and upper back is a large spot of whitish feathers
resembling that in the adult of Sula nebouxii. A further resemblance to the latter species shows in
the color of the legs and feet of immature dactylatra, which are said to be lavender-blue. The iris
is recorded as pale green, but is probably at first brown. After loss of the wholly white down, the
quills of wing and tail are as in the adult, and the ventral surface and a ring around the base of the
neck are white. The head and upper neck, back, and proximal parts of wings are mottled grayish
brown and white. The feathers of this juvenal plumage undergo considerable wear, which tends
at first to darken the areas referred to. At the time of post-juvenal moult the dark feathers are
replaced by white, so that the birds have successively a mottled and spotted white neck, with
darker areas on the crown and back; after a length of time not yet determined they moult into a
plumage entirely white except for the tail and the distal parts of the wings.
A fledgling with down still clinging to the top of the head is nearly uniform grayish brown
dorsally, the feathers of neck, back, rump, and lesser coverts being edged with whitish. The
entire neck is of the same color as the back, the remainder of the under parts being white.
The eggs are two in number, although more than one chick is rarely or never reared. Bryant
(4859, 125) reports that the chalky coating is much thicker on the egg of this species than is true
of other boobies. Bent (1922, 195) records the average dimensions of 67 eggs, chiefly from Pacific
localities, as 67 x 46 mm., the extremes measuring 77 x 47, 65.2 x 48.5, and 60 x 40 mm. Lister
(1891, 294) records the weight of single eggs as ranging from 119-144 grams.
Distribution: Pan-tropical oceans, nesting localities being invariably close to flying-fish waters,
which apparently determine in part the distribution of the species. Breeding stations in the Atlantic
include Ascension, Fernando Noronha, Rocas Reef, South Trinidad, the Bahamas, and the Abrolhos
Islands off the coast of Brazil. In the Middle American region the species is found at suitable
islands of the Caribbean Sea and on cays in the Gulf of Mexico. Pacific nesting stations within the
South American region include the Galapagos Islands, La Plata off the coast of Ecuador, and the
twin islets of San Felix and San Ambrosio.
Peters (1931, 83) recognizes six subspecies of Sula dactylatra, although the
ranges he records are insufficient to cover the distribution of the species even in
the American region. At least three of these alleged forms concern us in the
present study, namely, dactylatra, which is regarded as the bird of the South
Atlantic and of the West Indies; californica, which breeds on islands off the
western coast of Mexico; and granti, described from the Galapagos and tacitly
accepted as peculiar to that group.
The subspecific distinctions among eastern Pacific birds are those assigned
848 OCEANIC BIRDS OF SOUTH AMERICA
by Rothschild (1915, 43) and are based, in the main, upon allegedly different
colors of the bills, the naked face and pouch, and the legs and feet. Mathews
and Iredale (1921, 75) have elaborated Rothschild’s classification to cover six
subspecies. They do not state, however, whether the differences apply to male
birds or females. Yet this is a fair question, for in all parts of the world the two
sexes of adult White Boobies are utterly unlike in the colors of their fleshy
parts. My own observation of living birds in the field, supplemented by com-
parison of a large number of museum specimens, has led me to the conclusion
that both Rothschild and Mathews have overlooked an important admonition
of caution written by Ogilvie-Grant (1898, 431) in a footnote to a description
of this booby in the ‘‘Catalogue of Birds of the British Museum.”’ Referring to
the colors of the soft parts, the latter author states:
Too much importance must not, however, be attached to these differences, for after making
allowance for the changes of colour caused by age, season, and sex, it must be borne in mind that
some of the records are probably taken from birds some hours after death, when the colours of the
gular pouch and legs are entirely altered, while some descriptions are taken from dry skins.
The soundness of Ogilvie-Grant’s remarks was impressed upon me at La
Plata Island, Ecuador, when, on February 17, 1925, I made a scrupulous exami-
nation—within arm’s reach, or at least as close as I dared stoop beside the
nests—of more than 20 pairs of White Boobies which were either still courting
or had just produced an egg or two. The females, as among most species of
boobies, were distinguishable from the males by their larger size and different
voices. An added distinction, namely that of the flesh colors, was uniformly
as follows: both sexes had bills which were horn-colored distally, but those of
males were bright orange-yellow at the base, while in females the same region
was pink or light red. The legs of males were olive-drab or khaki color, while
those of females were plumbeous. The differences in both bills and feet were
visible at long range, and were invariable among all these breeding adults.
Both sexes had bright yellow eyes and the skin of the face was black, so that
‘*Blue-faced Booby”’ is a misnomer so far as the birds of La Plata Island are
concerned.
Such observations are at least sufficient to indicate that subspecific division
within the limits of this species in the Pacific has thus far been very imperfectly
worked out, for which reason I shall treat the Masked Booby as a whole in
this biography, although recognizing well-marked Atlantic and eastern Pacific
races.
In a number of important ornithological contributions, such as those of
Rothschild and Hartert (1899, 178), Snodgrass and Heller (1904, 244), Gifford
(1913, 89), and Fisher and Wetmore (1931, 32), the Galapagos form of this
booby has been erroneously identified and recorded as Sula variegata, which is
the endemic booby of the Peruvian coastal islands. The mistake has been
corrected by both Rothschild and Wetmore.
In the South American region the great White Booby is a bird of the Tropical
and Sub-Tropical Zones of surface water, its distribution apparently being the
same as that of flying fishes, which make up the principal component of its
MASKED BOOBY 849
diet. Most of its known breeding grounds are at oceanic islands, such as Ascen-
sion, Fernando Noronha, Rocas Reef, South Trinidad, numerous stations in
the West Indies, and San Felix, the Galapagos, and more northerly islands in
the eastern Pacific. Its coastal range belongs to belts of warm, blue, and clear
water in northern South America, between breeding outposts at the Abrolhos
Islands, Brazil, on the east coast, and La Plata Island, Ecuador, on the west.
The species avoids, of course, the littoral of muddy waters between northeastern
Brazil and Trinidad, but it occurs as a breeding bird at Los Hermanos Islands in
the Caribbean, and from here westward to Alacran and other low sandy reefs
in the Gulf of Mexico.
On the Pacific coast of South America, this White Booby is one of the species
which serves as an index of the advancing water of the countercurrent from the
north. It is unknown in the zone of normal upwelling along the shores of Peru,
but, during influxes of El Nifio between December and April, examples fre-
quently fly southward past Point Parifias, so that the oceanic range of the species
comes to overlap that of the normal bird life of the Humboldt Current. Such
vagaries are not to be wondered at, because the distribution of flying fishes
undergoes this same extension during the same periods.
It is evident that in the zone of relatively warm waters which lie to west-
ward of the Humboldt Current, the White Booby regularly reaches much higher
latitudes. I have seen a specimen from latitude 11° S., longitude 88° W., taken
on Christmas Day, 1912, and the late Dr. Frederic A. Lucas, former director of
the American Museum of Natural History, once shot an example equally far
out over the high sea off the coast of southern Peru or northern Chile. The
source of these was no doubt at San Ambrosio or San Felix, where my colleague,
Dr. James P. Chapin, found these boobies in residence during February, 1935.
He collected four females at San Felix, and one male a day’s sail to eastward of
that island. His birds are all adults in non-breeding condition, but two of the
females possess on the ventral surface a few dark fleckings which are the remains
of the immature plumage. He describes the iris of the male as bright lemon-
chrome, the bill as dull ochreous lemon-yellow, with the bare skin of face and
chin blackish, and the feet “‘olive-green.’’ The females had yellow eyes and
blackish faces, with the bill dull yellow, basally pinkish, and the feet ‘‘olive."’
The stomach contents of these birds included small squids and their mandibles
together with remains of fishes. The example mentioned above as being shot
by Dr. Lucas contained a flying fish 28 centimeters in length.
At Ascension, which is the type locality of this species, the White Booby
breeds among the Brown or Common Boobies on the flat top of Boatswain-bird
Islet. Perhaps its most populous present colony in the South Atlantic is at
Rocas Reef, directly northeast of Cape Sio Roque, Brazil, where the leader of
the Cleveland Museum South Atlantic Expedition estimated that there were
1500 nests on New Moon Cay during the month of April. This species, in fact,
here far outnumbered the Brown Booby. At Orquilla in the Caribbean, Lowe
(1911, 207) found the birds breeding in January, making no attempt at actual
nest-building but occasionally toying with small sticks. I judge from many
850 OCEANIC BIRDS OF SOUTH AMERICA
records in the literature that this booby may breed at any time of year within
the tropics, but that at many localities the nesting season is rhythmic, for the
population as a whole, with relation to the local rainy season.
During my work along the coasts of northern Peru and Ecuador, I found the
White Booby common off the Gulf of Guayaquil and in Santa Elena Bay during
January and February, and collected one specimen as far southward as Talara.
Apparently the birds avoid islands close to the shore, or those lying in bights
such as the Gulf. They were unknown, for example, to the observant lighthouse
keeper at El Muerto. At La Plata Island, however, we found them breeding in
the lush rain vegetation above the cliffs of the southerly end, on February 17.
- So far as I can learn, this colony, previously unreported, is the closest one to
the Pacific coast of South America. Hitherto the species had been known as a
breeding bird in this general region only at the Galapagos Archipelago.
The great white birds, with black-tipped wings and gleaming yellow eyes,
were at this season completing their courtship or already sitting upon one or
two eggs in a field of enormous white, yellow-hearted spider lilies or ‘‘aman-
caes’’ (Hymenocallis). The birds and the flowers harmonized completely. The
boobies notified us of their presence before we saw them in the knee-deep vege-
tation, for the males piped up their rather pathetic whistles and the females
blew their clamorous trumpets. Reithmiiller (1931, 142) states that the male
of this booby has a quacking call, the female a loud hissing whistle, but this
is exactly the reverse of the truth, as I found by a dissection made on the spot.
The sexual differences in voice correspond, in fact, with those of the Blue-footed
Booby, and are correlated with an identical structural difference in the syrinx.
In the case of the White Booby, however, the eyes of adult males and females
are alike, whereas in the Blue-footed Booby they differ as markedly as the voices.
All of the nesting White Boobies at La Plata had curious blackish blue,
cloudy spots on the outer white feathers of their throats, just below the pouch.
Sometimes there were half a dozen of these, and while I was examining them
on living birds I found, to my astonishment, that the spots changed their posi-
tion and shape. Closer inspection showed that the marks were made by hippo-
boscid flies, buried just under the surface of the snowy feathers so that they
were only half veiled. They were present at all times among the feathers of
every one of a large number of nesting birds, and always confined to the throat.
Possibly they selected this part of the booby plumage as a retreat because it
was the only accessible area which afforded shade from the full glare of the
equatorial sun.
Most of the nesting boobies were altogether fearless, although some of those
having only one egg took flight at our too close approach. Those with a full
set of two eggs were invariably ready to take the offensive as soon as we had
come within reach, demonstrating once again the conditioning which is a con-
comitant of egg-laying. The birds trumpeted or whistled, according to their
sex, and one of them succeeded in biting the finger of a member of our party
sufficiently to draw blood. Frequently they revealed their troubled state merely
by disgorging. One of them ejected a pile of seven flying fish, each 15 to 20
MASKED BOOBY 851
centimeters in length, which were practically as good as new and were immedi-
ately appropriated as bait by the lighthouse keeper of La Plata. This individual
informed me that he and his son obtained all their bait for fishing by tickling
the throats of these boobies with a switch and, furthermore, that flying fish
made up the only recognizable part of their diet he had ever seen them disgorge.
Since adult flying fish tend to avoid continental coasts, and even those of islands,
the feeding habits of the White Booby would suffice to account for its predilec-
tions regarding nesting stations. Snodgrass and Heller (1902, 512) call attention
to the relatively great distances from shore to which this large booby extends
its foraging, and they conclude that its daily excursions may sometimes carry
it from 150 to 175 kilometers away from its home island.
Major Chapman Grant has sent me an observation from the Caribbean
relating to the capture of prey by this species, and indicating that flying fishes
are taken chiefly by being dived after, rather than by being caught in the air.
On September 24, 1930, only a half day along the route between Cristobal and
Porto Rico, Major Grant watched two White Boobies for about an hour as
they accompanied the steamship ‘San Mihiel.’ The birds soared with only
occasional wing-beats, apparently taking advantage of wind deflected from the
bow. Numerous small flying fish were being scared up by the advancing vessel,
and the birds gave every evidence of making the same use of a ship that an ani
does of a horse in its insect-hunting. The sea was rough, making exact observa-
tion difficult, but every little while one or another of the boobies would spy a
fish and dart downward with the wings partly closed, yet still in such complete
control that it might turn up again when only a meter or so from the surface.
Whenever a dive was completed, the wings seemed to be about three-fourths
folded at the instant of submergence. The birds appeared to penetrate the clear
Caribbean water to an extraordinary depth, perhaps from 2 to 3 meters, and a
burst of bubbles indicated the large amount of air released from their lungs or
carried down in the plumage. Within six seconds, or thereabouts, they would
pop up to the surface and, if the dive had been successful, would float for a
moment with the bill and face held beneath the water while preparing to swal-
low their catch.
In the prevailingly birdless stretch of the Sargasso Sea, between the Azores
and the Lesser Antilles, Nicholson (1931, 274) observed a Masked Booby follow-
ing his ship for half an hour on a day in the middle of October, and diving
repeatedly from a height of 12 meters above the water. During the plunges,
its conspicuous black tail was fanned out as a rudder. The same author mentions
an example shot not far off the coast of British Guiana in August, 1929, and now
preserved in the Georgetown Museum.
Interesting details regarding the life history of this species have been pub-
lished by many observers in various parts of the world. Some of the notes,
such as those of Reithmiiller, refer to Australasian birds of the large-billed race
which has been called by the subspecific name personata. The behavior, however,
undoubtedly applies to the species as a whole, a supposition of which we may
be all the more confident because much of it is entirely in harmony with that of
852 OCEANIC BIRDS OF SOUTH AMERICA
certain other species of boobies. One point that immediately becomes evident
from.the common discoveries is that the White Booby requires a more or less
bare and open terrain for its nesting sites. It would, therefore, be barred from
forested islands such as Cocos. At La Plata, as I have noted, the birds were
nesting in a tangled bed of greenery, but this was no more than transient ground
vegetation, and the boobies could readily walk to the edge of the cliff close by,
whence, indeed, they customarily took flight. Beck (1904, 8) has noted that
at the Galapagos this booby usually nests in similar situations, near the edges
of high cliffs above the ocean, although to some extent it also occupies sandy
islands which rise barely above sea level. Lowe (1911, 207) states that it always
seems ‘‘more at home’’ where higher nesting ground is available. At some
islands, such as Clarion of the Revilla Gigedo group, birds of this species nest
at all levels, from the beach to the summit. Anthony (1898, 4) states that at
San Benedicto Island, of the same group, they seemed to nest later than the two
other resident boobies. At the end of April he found them guarding the nesting
territories they had appropriated, even though eggs had not yet appeared.
Reithmiiller reports that the first indication of an approaching breeding
season is shown by the curious courtship antics of pairs of these boobies on the
beaches. One of a couple will walk away, pick up a small stone, and return to
place it on the ground in front of the other bird which will, as a rule, accept it
and then slowly and deliberately place it on the ground again. This procedure
may continue for an hour or two, during which any other bird that comes near
is warned away by pugnacious posturing and bluffing on the part of the courting
pair. Reithmiiller believed that such behavior is peculiar to this species but,
as a matter of fact, it agrees entirely with that of the Blue-footed Booby (Sula
nebouxii), showing how fundamental such reactions may be.
Two eggs make up the normal clutch of the White Booby, and the birds
incubate by folding the webs of their broad feet around the shells, the dense
plumage of the breast then covering the feet as well as the eggs. Boobies
apparently do not develop bare brood-patches such as characterize so many
other waterfowl, including both petrels and penguins. The advantage of the
warm web membrane, with its rapid circulation of blood, as an incubating
surface is therefore particularly apparent. The blindness of the instinctive
brooding impulse is shown by these and other boobies in their willingness to
accept ‘‘nest eggs’’ of the crudest sort, such as water-worn beach shells. Anthony
(1898, 4) found that they seemed quite content when snails of the proper size
were substituted for eggs taken from beneath them. Still more strange and
suggestive is his observation that a bird, which had been incubating a single
egg, accepted two shells, tucking them under its breast with its bill, but within
a short time discarded one of them, as though unpleasantly stimulated by the
change from a single object to two. Other birds which had been covering two
eggs accepted permanently a pair of shells, continuing to guard and warm them
for ten days or longer.
The two eggs are laid several days apart, one chick consequently hatching
well before the other. All observers seem to agree that rarely or never is more
MASKED BOOBY 853
than one youngster reared. Reithmiiller says that two young are not found in
the nest together for more than three days after the second egg has hatched,
and he, as well as Snodgrass and Heller (1902, 512), believes that the elimi-
nation of the second and weaker offspring is due to the voracity cf the first-born,
which causes the parents to react so as to give it all of the food, thus allowing
the weaker chick to starve. Fisher (1904, 91) makes the same interpretation,
remarking that the smaller nestling, trampled to death, may remain in the nest
for a long time. It is probable, however, that this result cannot fairly be as-
cribed wholly to the behavior of the first chick. Doubtless, the adults of this
species are ill-conditioned to the presence of more than one young bird in the
nest. An interesting experiment would consist of apportioning two young of
equal age and strength among each of a number of nests. Under such circum-
stances I believe that the end would be the same, namely that the parent birds
would, for one reason or another, concentrate upon one of their two charges,
neglecting the other with fatal effect.
The young White Boobies, as long as they are brooded, keep their heads
tucked under the parent, even though the body remains exposed to the sun.
This might be interpreted as an escape from light instead of heat, but it is note-
worthy that the chick also climbs on top of the large feet of its parent at every
opportunity instead of sitting upon the hard and often blisteringly hot ground.
Possibly the fact that there is room for but one of the youngsters to obtain
insulation of this sort is one of the reasons why two chicks cannot survive. If
nestlings are moved a few meters away from the nest site the parents fail com-
pletely to recognize them and continue to center their interest for a time upon
the slight scrape, encircled by a whitewashed ring, which is a poor apology
for a nest.
The parent returning with food swoops in swiftly from sea, applies the
brakes very abruptly by turning upward and beating its wings, and then drops
beside the home site. The chick thereupon vigorously attacks, not only picking
at its parent's beak, but also striking with its wings. In the feeding process
its head is inserted far into the throat of the adult, where it remains for a long
time, picking and jabbing and pumping in what looks like a most uncomfort-
able manner, until all of the available flying fish have been extracted. The
inordinate length of time devoted to the feeding of a chick, which has been
especially mentioned by Fisher, may be still another reason why no food ever
remains in the gullet to profit the second offspring. When an intruder enters
the territory of a White Booby family, the youngster joins its parent or parents
in hissing or barking defiance. The adults appear extremely formidable with
their feathers on end, their bills half open, and the pupils of the eyes contracted
to a speck in the middle of the bright yellow iris (Lister, 1891, 294). The
chicks have brown eyes.
The size and strength of this species, which is the largest of the boobies, is
still not sufficient to protect it from the persecution of the man-o’-war bird.
Dill (1912, 19) reports that one of the latter pirates was seen to pursue a White
Booby, seize it by the tail, and completely overturn it in the air.
854 OCEANIC BIRDS OF SOUTH AMERICA
BROWN BOOBY
Sula leucogaster leucogaster
Pelecanus Leucogaster Boddaert, 1783, Table Planche Enlum., p. 57, No. 973 (Cayenne).
Names: Common Booby, ‘‘Pajaro Bobo,”’ “‘Alcatraz.’’ In Brazil, both the latter name and
“Murgulhao”’ are applied to this booby. Synonyms of the specific name include fiber, sula, parva,
brasiliensis and australis.
Characters: A brown booby with white ventral surface, the hue of head and neck being some-
what darker than that of back and wings.
Adults (sexes alike except as to size): Head, neck, and chest clove-brown; remainder of dorsal
surface, including the readily visible parts of wings and tail, of distinctly paler brown (close to
mummy brown or bister), the primaries somewhat blackish on their outer webs; secondaries
basally whitish, especially on the inner vanes; shafts of wing quills blackish above, paler below,
those of the rectrices basally whitish; ventral and lateral surfaces, caudad from the chest, white;
axillaries and median under wing coverts white, the remainder of under-wing brownish. Iris pale
gray or whitish; eyelids bright blue, with gray skin above, below, and in the loral region; remainder
of face, gular pouch, and base of bill yellow, shading into bluish horn-color toward tip of bill;
legs and feet chrome-yellow (often appearing green in dried skins).
13 males from Fernando Noronha, Ascension, St. Thomas, and Dry Tortugas: wing, 372-391
(381); tail, 169-198 (186); exposed culmen, 87.8-101 (92.7); tarsus, 42-48.4 (44.3); middle toe
and claw, 72.5-81 (76) mm.
10 females from Brazil, Fernando Noronha, Ascension, St. Thomas, and the Bahamas: wing,
384-415 (400); tail, 162-198 (180.5); exposed culmen, 91.8-102 (96.3); tarsus, 45-48 (46.8); middle
toe and claw, 79-86.6 (82.8) mm.
Length, males, 71-76 cm.; females, 76 cm. Wing-spread, males, 135-144 cm.; females, 145-
147 cm.
The figures agree substantially with those from a series of breeding Cape Verde Island birds
(Murphy, 1924, 253).
In juvenal plumage boobies of this species are almost uniformly grayish brown above, only
slightly lighter on the belly, and darker on the breast. Even in such immature examples the feather-
ing of the neck is distinctly darker than that of the back, supplying a character differentiating
such birds from similar stages of the eastern tropical Pacific race (etestaca). The primaries of such
young birds are distinctly blackish. The ventral surface, over the entire area which is white in
the adult, is composed of pale gray feathers, with broad subterminal ashy brown bars succeeded by
a narrow whitish band. The general effect is, therefore, brownish gray instead of white. The bills
are evidently darker than those of adults. The down of young nestlings is pure white.
Sets of eggs usually number two, but one and three are also not uncommon. They are bluish
white, with the usual calcareous coating, and are exceedingly variable in form (Murphy, 1924,
254, fig. 10). Two sets obtained by Beck at Cockroach Islet, off St. Thomas, August 10, 1916,
measure 64.3 x 41.6, 60.8 x 41.2; and 57.5 x 40.4 mm. The extremes of a large series recorded by
Bent (1922, 204) are 65.5 x 41, 62 x 42.5, 52.5 x 40, and 56.5 x 34.5 mm.
Distribution: Pan-tropical Atlantic, breeding at Ascension, Fernando Noronha, Rocas Reef,
St. Paul Rocks, the Cape Verde Islands, many islets off the coast of eastern South America, and at
numerous localities in the Caribbean and the Gulf of Mexico, northward to the Bahamas. The
species occurs in tropical and sub-tropical seas throughout the world, but distinct races inhabit
islands off the west coast of America.
Opinions may differ regarding the relationships of the Red-footed Boobies
(Sula sula) on the two sides of the Isthmus of Panama, but there can be no ques-
tion about the fact that the Brown Booby finds in this strip of land an effective
barrier against natural distribution from either oceanic region to the other.
The birds of the Caribbean side are of the typical race, which appears to have
spread over the entire tropical Atlantic—northward to the Bahamas, eastward
BROWN BOOBY 855
to the African coast, and southward beyond the tropic of Capricorn along the
shores of Brazil. The Brown Booby of the Pacific coast of America is, on the
other hand, a very distinct bird, in which the male is characterized by a hoary
gray head and throat. There are, in fact, two different subspecies of Brown
Boobies of this type along the west coast of America. The northern race (Sula
leucogaster brewsteri) ranges from Lower California southward to Clipperton
Island, and thus belongs to a prevailingly arid zone. The other (Sula leucogaster
etesiaca), the only Pacific form of the Brown Booby falling within the scope of
this book, is a race belonging to a highly humid zone, the range of which
extends from western Panama and Cocos Island southward along the rainy
coast of Colombia to northern Ecuador. It will be considered further in the
next biography.
In the Atlantic the Brown Booby scarcely ranges outside the zone of dis-
tinctly tropical water. It breeds at oceanic islands not far from the equator,
such as the Cape Verdes, St. Paul Rocks, Fernando Noronha, and Ascension, as
well as along the Antillean Arc, but it apparently does not reach either St.
Helena or South Trinidad, both of which lie in sub-tropical water. Gulf Stream
influences carry it northward to the Bahamas; and along the South American
coast, where the warm Brazil Current sweeps southward, it inhabits many
coastal islands as far as Santos or even Santa Catharina. According to Goeldi
(1894, 594), the bird is familiar to all inhabitants of the Brazilian coast, and is
not uncommon in the bay of Rio de Janeiro. Burmeister (1856, 458) remarks,
however, that it does not habitually come as close to the continental shore as
do the man-o’-war birds. The trait implied, which I believe to be characteristic
of boobies in general, goes far to explain why the two sides of Middle America
are occupied by distinct races, whereas one and the same man-o'-war bird flies
back and forth across the Isthmus with complete freedom.
To southward of southern Brazil the Brown Booby is known only as a casual
or accidental wanderer. It has been more or less doubtfully reported, for example,
from the Falkland Islands (Bennett, 1926, 329). A record from “‘Punta Arenas”’
has also been much repeated in the literature, but it appears that the original
specimen responsible for this was captured in Costa Rica and not in the Strait
of Magellan.
In more northerly South America the Brown Booby inhabits even the muddy
coast of Guiana from where, in fact, the species was originally described. While
I find no record of its breeding in Guiana, it is very likely that there are nesting
stations on some of the islets off the French colony. Along the coasts of Trini-
dad it is particularly common, according to Léotaud (1866, 560), during the
season of winter rains. From here it is but a step to its headquarters on the
Caribbean coast of Venezuela, where the Brown Booby is one of the commonest
of sea birds, to be seen at times by thousands in the channel between Margarita
Island and the mainland. From this point westward and northward it breeds
wherever there are islets well offshore and not yet overrun with predatory ani-
mals, such as the Islas de Aves, Los Hermanos, and the Testigos of the leeward
chain, and many localities among the Antilles and Bahamas.
856 OCEANIC BIRDS OF SOUTH AMERICA
In its style of flight this species is perhaps the least spectacular and inspiring
of the boobies. As Cory (1880, 191) puts it, its maneuvers appear to be decidedly
for work rather than for pleasure. However, such remarks are merely compar-
ative, for even the least of boobies is a master of the air. Bangs (1902, 395),
who saw large numbers of mingled Brown and Red-footed Boobies during a
violent gale on the peninsula outside Indian River, Florida, on February 16,
1895, describes how the birds assembled in bands in the raging wind in order
to plunge for fish just outside the line of breakers. The boobies appeared not
to be in the least incommoded by the gale and the driving rain, and acted, in-
deed, as though experience had taught them that such weather meant good
fishing. Bryant (1859, 193) tells us that the Brown Boobies are capable of diving
repeatedly, in very rapid succession, from a height above the water scarcely
equal to the spread of their wings; he once saw a bird catch a dozen fish within
the space of a minute by making such short plunges. In calm weather the Brown
Boobies beat their wings, of course, much more than during a high wind, and
progress with slow and steady strokes, which Friedmann (1927, 146) describes
as gull-like rather than duck-like. Parties of birds often travel in single file.
The force of the breeze also has much to do with their ability to take off,
either from the water or from the ground. At times they appear unable, or at
least very unwilling, to undertake the effort of rising from a level surface.
They will rather stand their ground and snap and hiss at invaders of their
domain or, if they are driven to taking wing, they will strike the soil or the
vegetation for the first ten to twelve strokes. The advantage offered by resting
places well above the ground induces them at times to perch in trees, from where
they can spring forth regardless of the presence or absence of wind and, by
means of a downward glide, gain sufficient momentum to send them safely on
their way, after which they soon rise with strong wing-beats. Peters (1929,
134) observed a score of these birds that came nightly to roost in coconut palms
overhanging the water at Great Corn Island in the western Caribbean. While
by no means as apt a tree fowl as the Red-footed species, the Brown Booby
handles itself rather better on slender and precarious perches than do most
members of the family. In the equatorial South Atlantic I saw one alight on
the tip of the main boom of the brig ‘Daisy’ before dark of a quiet evening. At
five o'clock next morning the bird was still asleep on the same gently swaying
and pitching spar. At Porto Rico, Wetmore (1918, 337) found evidence of the
boobies’ continual contact with vegetation in the form of thorns, or even small
lobes of cactus, clinging to their feet and feathers and demonstrating, inciden-
tally, how such prickly plants might become widely distributed through the
migratory or irregular wandering of the birds.
Observations made at’various seasons on the plateau of Boatswain-bird Islet,
Ascension (Moseley, 1879, 563; Penrose, 1879, 281), at St. Paul Rocks (McCor-
mick, 1884, 20; Nicoll, 1904, 37; Wilkins, 1923, 478), and at Fernando Noronha
(Simmons, 1927, 69) show that the tropical breeding season of the Brown
Booby is continuous, so far as concerns the population as a whole. Farther
from the equator, as in the West Indies, the birds appear to be somewhat more
BROWN BOOBY 857
seasonally rhythmic in their nesting activity, though even here there are great
irregularities. Cory (1880, 191) states that there is a definite migration to the
Bahamas, beginning about February 1. During April at the same islands
Bryant (1859, 123) found, however, not only full-fledged young already flying,
but also newly hatched birds and many eggs. At Desecheo Island, Porto Rico,
Wetmore visited a colony of 8000 to 10,000 Brown Boobies in June, when the
young were full grown, and yet Beck, during the course of the Brewster-Sanford
Expedition, found eggs still in some of the nests at Cockroach and Cricket
Islets, off St. Thomas, on August 10, 1916.
As a nest-builder, the Brown Booby seems to be somewhat intermediate
between such species as the Blue-footed and Masked Boobies, which produce
nothing more than a scrape, and the tree-nesting Red-footed species, which
often makes use of a great quantity of twigs and leaves. In certain localities
the Brown Booby can hardly be said to build a nest at all, but in places where
twigs, stones, or seaweed are readily available it usually gathers together, per-
haps as part of the courtship procedure, a slight accumulation upon which the
eggs are laid. The nature of the ground appears to be of relatively little im-
portance to the birds, although a bit of altitude, a slope, or proximity to some
sort of jumping-off place confer sufficient advantage so that they appear to be
more or less consciously selected. Vegetation is no detriment, provided it is
neither dense nor high enough to interfere with take-off and landing. The
breeding grounds therefore vary between terrains which are little more than
bare, damp stone, as at St. Paul Rocks, or sun-baked guano, as at Boatswain-
bird Islet, and the sandy stretches of Bahaman cays which are covered more or
less thickly with wire-grass, prickly-pear, and sea-grape (Coccolobis uvifera).
In such a situation as the last named, a colony of about 1500 pairs of Brown
Boobies was studied by Chapman (1908, 141). The birds here occupied com-
paratively level ground and the nests, most of which were scantily lined, were
placed 2 to 3 meters apart, the included circle of territory being violently de-
fended against interlopers of their own species. In the main, the boobies were
silent, but when aroused they uttered raucous screeches. The eggs, which
usually numbered two, began to appear in February. About a week intervened
between the laying of successive eggs in each nest and, since incubation began
as soon as the first appeared, the doom of the junior chick would have been
sealed far in advance even if there had not been an apparently high percentage
of infertility among the eggs. McCormick, too, found that at St. Paul Rocks,
in December, 1839, all but one of the two or three eggs in Brown Booby nests
proved as a rule to be addled. In the Bahama colony, according to Chapman,
two chicks in a nest were so unusual that such families totaled only a fraction
of one per cent of the population.
The young Brown Boobies are, of course, hatched without a feather on their
livid skins, and they are constantly brooded by one of the parents until the
white down clothes them. After the chicks have grown too large to be covered,
they lie for considerable periods flat on the ground, with eyes closed, giving
every appearance of being dead. Aside from the high prenatal mortality men-
858 OCEANIC BIRDS,:OF SOUTH AMERICA
tioned above, however, the great majority of the chicks seems to survive the
nesting period. About three months elapse between the time the egg is laid
and the date when the chick takes flight. The young are fed upon squids and
fish which they obtain by thrusting their heads into the parents’ gullets. Cory
(1880, 191) states that even flying progeny still depend upon the adults for food.
This matter deserves further investigating, however, because there is evidence
that young boobies, like young petrels and albatrosses, are permanently aban-
doned soon after they begin to deserve the name of fledgling.
Chapman continues as follows with a description of a typical day in the
Bahaman Brown Booby colony. Activity began on March 9, for example, at
5.15 a.m., and for some minutes a subdued quacking was heard throughout the
colony. Within a quarter of an hour there was a general movement toward
the sea, but one parent of each couple remained with its egg or young chick.
Throughout the day exchanges at the nests were taking place sporadically,
but not until dusk did the birds begin to return en masse from the ocean. Before
this time the frigate-birds had already retired for the night, a circumstance
which may have had more or less to do with the later hours of the booby.
Both parents spent the night at the nest, one squatting and brooding, the other
standing beside it. Young and adults kept the tip of the bill tucked into the
down or feathering of the shoulders. Wetmore’s observations in Porto Rico
led him to conclude that the Brown Boobies show much activity at night as
well as by day, and that they sometimes do part of their fishing during the hours
of darkness.
Half-grown chicks often react much more savagely toward an intruder than
the adults do (Nicoll, 1904, 37). So long as the young remain covered with
down, and are confined to the nest site, they are, in fact, exceedingly noisy and
aggressive in the presence of potential danger. They will reach forth as far as
possible to lunge with their bills, all the while keeping up the utmost possible
clamor. When, as fledglings, they have once left the nest, however, they tend
to become timid, and are quick to scurry out of the way of an intruder or to
take flight. A selective advantage is to be seen in these responses correlated
with age. The only effective defense of an altricial chick, tied by its own
weakness to one spot on the ground, would be to intimidate a natural enemy
by its savage outcry and apparent ability to take care of itself. On the other
hand, the safest of all measures for a fledgling would be to fly away from danger.
By most observers the voice of the Brown Booby has been described as a
quack, a series of grunts, or as strident screeches, without an attempt to dis-
tinguish between the notes of the two sexes. Reithmiiller (1931, 143) is more |
specific in stating that the male quacks and the female hisses, except that I
believe he has here reversed the facts. Among at least two other boobies
(nebouxii and dactylatra), as I have shown elsewhere, the female is the possessor
of the sonorous voice, that of the male being a sibilant whistle, and these
differences are correlated with a structure of the syrinx which constitutes a
definite secondary sexual character.
Bryant (1859, 123) states that at the Bahamas the Brown Boobies always
BROWN BOOBY 859
seek their food in blue water, never in the shallows of the banks. Here again
we have a clue as to why the Isthmus of Panama presents a barrier to boobies,
notwithstanding that it is crossed so readily by pelicans and man-o'-war birds
which show no aversion to shores and estuaries.
Food taken from Brown Booby stomachs at the Bahamas included principally
flying fish and halfbeaks, but also flat-fish, parrot fishes, and large prawns.
Clark (1903, 285) writes that just off Carupano Point, on the Caribbean coast
of Venezuela, he noted a certain spot where hundreds of sea birds, including
Brown Boobies, pelicans, frigate-birds, gulls, and terns congregated to fish.
Every few moments the diving members of this large flock would plunge within
a single small area. Investigations showed that at this point sea catfish and
other marine animals were being incapacitated by sulphurous fumes from the
ocean bottom, and that the birds had assembled to take advantage of this. -
Little is known regarding the natural enemies of the Brown Booby, except
for the customary depredations of the man-o’-war birds. At St. Paul Rocks
great numbers of crabs move about among the nesting birds and, while they
appear not to be a serious hazard to chicks, McCormick saw them carry off
boobies’ eggs in their claws after the sitting birds had been disturbed. At the
same islets Nicoll observed how quick the crabs were to take advantage of the
flying fish disgorged by the adult boobies. Reithmiiller states that the nesting
boobies are sometimes much troubled by ticks.
COLOMBIAN BOOBY
Sula leucogaster etesiaca
Sula etesiaca Thayer and Bangs, 1905, Bull. Mus. Comp. Zodl., 46, No. 5, p. 92 (Gorgona Island, Colombia).
Names: This booby has been reported upon in the literature under the names Jewcogaster and
brewsteri as well as under its own subspecific name.
Characters: Differing from the Brown Booby (Sula leucogaster leucogaster) in that the sexes are
of dissimilar plumage, the male being gray-headed. In the female of etestaca the back and wings
are concolor with the head and neck, without trace of the demarcation so strongly evident in the
subspecies leucogaster.
The male, in which subspecific characters are still more striking, is thus described from a
Cocos Island specimen by Snodgrass and Heller (1902, 513):
Feathers of head just back of bare space very pale, nearly pure white above, almost immediately,
however, darkening into grayish and then into brownish gray, passing from this through grayish
brown on the hind neck, sides of head and throat into dark sooty brown on the back, upper surface
of wings, tail and upper breast, the brown darkest on under surface of the primaries. Lower
breast and belly pure white. Median lower tail coverts white, the lateral ones brown.
Snodgrass and Heller add that in the adult female the gular sac and the base of the bill are pea-
green, with a slate-blue spot in front of the eye, the legs and feet light yellowish. The feet of a
male are described as light pea-green.
3 males from the Pearl Islands and Cocos Island: wing, 365-382 (374.3); tail, 170-182 (178);
exposed culmen, 87-95 (90.3); tarsus, 43-50 (44.2); middle toe and claw, 74-76 (75) mm.
8 females from Gorgona, the Pearl Islands, and Cocos: wing, 360-412 (390); tail, 174-191
(186); exposed culmen, 93-102 (97.8); tarsus, 4448.5 (41); middle toe and claw, 79-83.5 (81.6) mm.
Birds in youthful plumage can be distinguished from Atlantic Brown Boobies of the same
stages by the uniform coloration of their necks and backs.
Gifford (1913, 99) shows that there is a wide though by no means unusual variation in the shape
860 OCEANIC BIRDS OFPYSOULTE AMERICA
and size of the eggs, which range in form between ovate and elliptical-ovate. In a series of 24 the
extremes and averages of length and breadth were as follows: 50.3-63.1 (58.7); 37.5-42.5 (39.8)
mm. Four sets of two eggs each measured as follows: 53.6 x 40, 54.5 x 40; 63 x 41.6, 58.9 x 39.5;
62.5 x 39, 59.7 x 37.5; and 58.3 x 40, 55.5 x 38.2 mm.
Distribution: The humid Pacific coast of tropical America, from southern Costa Rica south-
ward to northern Ecuador, and offshore to Cocos Island. Breeding at Gorgona Island, the Pearl
Islands and elsewhere in the Gulf of Panama, as well as at Cocos.
I have noted in the account of the Atlantic Brown Booby that its close rela-
tive, the Colombian Booby, belongs exclusively to a small and humid area of
the eastern tropical Pacific. The known range of this subspecies is, in fact,
restricted to the oceanic bight at the northwestern corner of the South American
continent. Cape San Francisco, Ecuador, probably marks the southern bounds
of its distribution, while Cocos Island is the outpost farthest from the mainland
shore. Just where the range of this booby terminates to northward, on the
coast of Middle America, is not yet certain, but its limits will doubtless prove
to be well south of the semi-arid zone of western Mexico. Specimens have thus
far been taken northward and westward to a point near the delta of the Rio
Grande de Terraba, Costa Rica. Peters (1931, 85) states that the range of
etesiaca probably includes the Galapagos Islands, but I believe this to be highly
unlikely on zodgeographic grounds, because of the prevailing aridity of that
archipelago. It is much more probable that Gifford (1913, 97) was correct in
inferring that the examples of “‘Sula brewsteri’’ (meaning etesiaca) reported from
the Galapagos were actually the young of dactylatra or of nebouxii. Formerly
the two Brown Boobies of the western coast of America, which are today
known by the subspecific names brewster and etestaca, were regarded as a single
form. They prove to be readily distinguishable, however, and it is exceedingly
interesting to find that the birds from the dry island of Clipperton are of the
former race, while those from humid Cocos are etesiaca.
In the climatic proclivities mentioned, there is every suggestion of a genetic
difference between the boobies concerned, however closely related they may
appear on ordinary taxonomic grounds. Sula leucogaster etesiaca everywhere lays
and hatches its eggs in nests that are perpetually drenched with rain-water, and
it is entirely possible—and doubtless open to experimental test—that such
humid conditions are in some way necessary to its existence.
A little north of Tumaco, Colombia, and far enough at sea to be out of sight
of the coast, I passed a male booby of this form, as it stood on a floating tree
trunk, on the afternoon of March 13, 1925. Its white forehead was sufficient to
distinguish it at long range. Females resemble more closely those of the typical
race of leucogaster, but differ in that the neck and mantle of etesiaca are of a single
shade of brown.
Gifford, during the California Academy Expedition, first saw this booby
50 to 60 kilometers from Cocos Island on September 1. Subsequently it was
discovered that the birds flew regularly offshore in the morning, and returned to
headquarters at evening. The principal colony was on a small islet at some
distance from Cocos, and situated between the outliers known as Nuez and
COLOMBIAN BOOBY 861
Cascara. Only two or three of the boobies were observed on the shores of the
main island.
At the Cocos colony the boobies were nesting in mid-September, one or two
eggs and both naked and well-grown downy young being found at the same
time in slight hollows amid grass and rocks on the steep, dripping slopes of the
islet. Among the sets of eggs collected here, eight were composed of singletons
and 16 of pairs. All were stained a dirty brown on account of the sodden char-
acter of the nests in a region where deluges of rain descend every day.
Thayer and Bangs (1905, 92, 141) report upon this booby at Gorgona Island,
Colombia, from where it was first described, and at the Pearl Islands in the
Gulf of Panama. Rendahl (1920, 10) and Sturgis (1928, 113) have added further
notes from the Pearl Islands. The boobies are abundant at Pacheca and Saboga,
at the northern end of this group, and also at the isolated islet of Galera, to
southeastward of San Miguel. At an unstated date, Sturgis found the birds
nesting on the ground among gaunt and leafless trees of Galera. The nests,
which were untidy heaps of twigs, contained either two eggs or a solitary
downy chick. Male and female adults were observed brooding over adjacent
nests.
At Taboguilla Island, within sight of the Pacific entrance of the Panama
Canal, Hallinan (1924, 306) found the Colombian Boobies breeding on December
5, 1915. The nests were constructed of sticks, fallen leaves, and a few feathers,
and were placed on a rocky shelf among shrubbery and cactus. Each contained
two eggs at this date. Hallinan observed a female booby in a tree with the tail
of a large fish projecting from its mouth. The prey, when recovered and mea-
sured, proved to be 35 centimeters in length and about 5 in diameter.
RED-FOOTED BOOBY
Sula sula
Pelecanus Sula Linnaeus, 1766, Syst. Nat., edit. 12, 1, p. 218 (Barbados).
Names: Tree Booby, Red-faced Booby. Synonyms of the specific name include piscator, rubri-
peda, erythrorhyncha, brasiliensis, candida, hernandexi, coryi, websteri, autumnalis, and nicolli. A large
number of subspecific names have also been applied to birds of this species.
Characters: A booby of many puzzling phases, some of which have been given taxonomic
status. Adults in the white phase have an entirely white plumage except for the quills and coverts
of the wings. Certain others are white with brown tails. Many of those in the brown or gray
phase have white tails. The species has relatively the longest tail of any booby, and it is also the
smallest member of the family occurring within the South American region.
Adults in the white phase (sexes alike except as to size and the colors of the naked face):
Plumage generally white, with a somewhat variable, terminal, yellowish or “‘golden”’ tint on the
feathers of the head, neck, back, and tail; primaries and their coverts, alula, greater upper wing
coverts, outer webs and distal portions of secondaries blackish brown, with a hoary gray or silvery
gloss on the outer webs of all; inner webs of most of these feathers paler, becoming white toward
the base of the secondaries; under wing coverts white with the exception of the median and greater
series, which are mostly grayish brown. Flesh colors are somewhat variable, and the sexual
distinctions have not yet been fully correlated. Males have gray or whitish irides, females some-
times, or perhaps always, brown or dark yellow irides. In males the bill is bluish, red at the base,
with green skin around the eyes and in the lores, but the eyelid blue; the gular sac is velvety black.
862 OCEANIC BIRDS OF SOUTH AMERICA
In females the center of the gular sac is gray or pinkish gray. The legs and feet of both sexes
are red, variously described as ‘'blood-red,"’ ‘‘coral,’’ “‘vermilion,’’ “‘salmon-red,”’ etc.
The so-called immature plumages, or the phases which have been given subspecific or specific
names, are discussed in the text below. In many parts of the world two or more of these phases
appear to be persistent throughout life. The situation is not consistent, however, for everywhere
at least a small proportion of the white birds seem to be present.
Measurements of white specimens:
9 males from Navassa, Little Cayman, Fernando Noronha, and South Trinidad: wing, 362-
385 (372.1); tail, 206-231 (217); exposed culmen, 76.3-85 (81.2); tarsus, 32.7-36.9 (33.7); middle
toe and claw, 66.2-74.5 (69) mm.
Length, 69-76 cm.; wing-spread, 147-150 cm.
7 females from the same localities: wing, 378-405 (389); tail, 198-215 (207.4); exposed culmen,
80.5-86 (83.7); tarsus, 35-40.3 (37.3); middle toe and claw, 70-75.5 (72) mm.
Length, 72-79 cm.; wing-spread, 146-158 cm.
From the island of Fernando Noronha and other South Atlantic localities the Museum has
eight examples representing the brown, white-tailed “‘cory#,"’ ‘‘autumnalis,”’ or ‘'nicolli’’ phases.
Some of these were mature enough to be nesting. Their dimensions and flesh colors agree completely
with those of white birds among which they were living. In five of these specimens the tail and
rump, as well as the lower belly, are entirely white. Ina sixth there is a mixture of gray feathers
among the rectrices, while the seventh has a tail largely gray, and with only a few whitish feathers
on either side of the vent. One of them seems to be acquiring on the crown of its head a yellowish
white plumage, similar to the same part in the white birds, and also white feathers among the
scapulars and wing coverts.
The brown-tailed or “‘webstert’’ type of Red-footed Boobies, from the Galapagos and other
Pacific localities, appear to differ very slightly, if at all, in size from Atlantic birds. Furthermore,
fully white adults crop out at least sporadically among their populations. I have not examined a suf-
ficient number of specimens to discuss their taxonomic status. Measurements of four are as follows:
2 males, Galapagos and Revilla Gigedo Islands: wing, 382-404 (393); tail, 189-221 (205);
exposed culmen, 86-87 (86.5); tarsus, 36-37 (36.5); middle toe and claw, 75-78 (76.5) mm.
2 females, Galapagos: wing, 384-402 (392); tail, 197-211 (204); exposed culmen, 88-92 (90);
tarsus, 38-40 (39); middle toe and claw, 80 mm.
In immature plumage the Red-footed Booby is wholly brownish, lighter ventrally. Examples
can be readily distinguished from the somewhat similar young of the Brown Booby (/eucogaster)
by the shape of the rectrices, which are slender in the former and notably broad in the latter.
The rectrices of juvenal examples of Sula sula are, nevertheless, broader than those of adults,
whereas the primaries of the young birds, on the contrary, are narrower than those of adults.
The gular sac is pinkish; the legs and feet dull yellowish.
The down is white, and the naked skin of newly hatched chicks plumbeous.
Unlike most other boobies, this species lays, as a rule, only one egg. The bluish shell is covered
with a rough, lumpy, and usually much scratched chalky deposit. The form is highly variable.
Bent (1922, 212) records the extreme measurements among 38 examples from various sources as
72 x 48.5, 59 x 40.5, and 69 x 35 mm. The average of the series was 62.7 x 41.4 mm.
Distribution: Breeds chiefly at islands far from continental coasts throughout the pan-tropical
oceans. Within our region one or more forms of the Red-footed Booby nest at South Trinidad,
Fernando Noronha, numerous Caribbean and West Indian localities, and at Cocos and the Galapagos
Islands. Formerly the species inhabited also the island of Ascension, but apparently it does not
at the present day.
Both the technical name and the type locality of the Red-footed Booby, a
bird of wide distribution in the pan-tropical seas of the world, have been sub-
jects of much disagreement and uncertainty. In 1915 Mathews designated
Ascension Island in the Atlantic as the terra typica of the Pelecanus sula of
Linnaeus, a most unfortunate choice for reasons discussed in Part I of this book
RED-FOOTED BOOBY 863
(p. 154). The decision has, however, been accepted by Peters (1931, 84) and
other recent writers. Fortunately, Grant and Mackworth-Praed (1933, 185)
have now shown that the correct type locality for the bird of Linnaeus is the
island of Barbados, British West Indies, a district in which this booby finds an
abundance of tree- and shrub-covered islands suitable for its nesting, and in
which it has always remained an abundant sea fowl.
Of the three subspecies of this booby listed by Peters, only two pertain to
our region, namely the typical form which is the bird of the South Atlantic
and of the Caribbean-Gulf bight, and the subspecies known as Sula sula websteri,
which is presumed to be the eastern tropical Pacific race, occupying islands
from the Galapagos northward to the Revilla Gigedos.
There is more logic in the case of boobies than in that of most other Pelecani-
form birds for assuming that taxonomic differences exist between examples
occurring on opposite sides of the Isthmus of Panama. The reason for this is
that boobies in general shy off continental coasts and, so far as I can learn,
they rarely, if ever, cross extensive bodies of land. Pelicans and man-o'-war
birds are familiar creatures throughout the length of the Panama Canal and
the passage back and forth is so simple for them, and of such frequent occur-
rence, that it would be zodlogically unreasonable to expect a distinct race of
either on opposite coasts of this region. The boobies, however, have achieved
a measure of definite isolation by the emergence of the Isthmus of Panama as a
wall which has not always existed between the Atlantic and the Pacific. In
the case of at least three species of boobies, we know that this barrier has been
an effective one. For example, Sula nebouxii, a common bird of Pacific waters
in the tropical American region, is unknown from the Caribbean side. Sula
dactylatra is represented by distinct Atlantic and Pacific subspecies. Further-
more, the Atlantic Brown Booby, which ranges from the Cape Verde Islands
and Ascension westward into the Caribbean and the Gulf of Mexico, is replaced
on the Pacific side of the narrow continental connectant by a peculiarly well-
marked subspecies (Sula leucogaster etesiaca).
Under such circumstances, the simplest taxonomic treatment would doubt-
less be to recognize the eastern Pacific race of the Red-footed Booby as distinct
from that of the Atlantic, and to treat them in two separate accounts. Never-
theless, I cannot bring myself to do this because the differences which have been
so often pointed out seem to me to be ill-defined and even contradictory, and to
be, in fact, of the same nature as the still unexplained individual variations to
be noted among single colonies of the Red-footed Booby in practically all parts
of the world.
The puzzling point about the Red-footed Booby is that birds not only exist,
but apparently breed, in three distinct color phases, which may be broadly
termed the white, the gray, and the brown, although such comprehensive dis-
tinctions as are implied by these names are further complicated by the variable
color of the tail, which is sometimes white in gray and brown birds, etc. Age
alone does not appear to offer a satisfactory explanation of these differences, for
in certain localities the great bulk of the population is always gray, while at
864 OCEANIC BIRDS OF SOUTH AMERICA
other places the majority of the individuals are white. All attempts to base
taxonomic distinctions upon these differences appear to lead to absurdities.
Grant and Mackworth-Praed (1933, 118) have sought to escape the dilemma
by boldly cutting the Gordian knot. They have described as a wholly new
species the ‘White-tailed Red-footed Booby’’ (Sula nicolli), said to differ from
Sula sula ‘in having the head, neck, mantle, wings, breast, and abdomen ash-
brown, with a slight gloss or sheen; the head and neck have a golden tinge and
the mantle and upper side of the wings are rather darker than the rest of the
plumage; . . . rump, tail, vent, and thigh-feathers white.’ The distribution
assigned includes Madagascar, Mauritius, Raine’s Island, Samoa, Navigator
and Henderson Islands, and the West Indies!
In other words, these authors hold that there are two species of Red-footed
Boobies, each distributed pretty much all over the tropical oceans and each
breaking up into several subspecies. While they may be right, I can only hold
that they have by no means made their case. Specimens to support my doubts
are numerous, and I can refer the reader to excellent photographic portraits of
both these ‘‘species’’ nesting at the small island of Fernando Noronha (Simmons,
1927, 69, 70), as well as to observations summarized below.
At South Trinidad, Wilson (1904, 211) observed four birds in the completely
white plumage and one in brownish plumage breeding on September 13, and
Ribeiro (1919, 186) has since described from this same island, under the sub-
specific name autumnalis, a breeding phase in which the head, neck, back,
breast, and wings are chestnut-brown, the lower back, rump, belly, and tail
yellowish white. The author states that he describes this race ‘‘for want of
better solution of certain plumage problems.”’ If the proposal of Grant and
Mackworth-Praed should prove to have substantial merit, their new species
would become a synonym of Sula autumnalis Ribeiro, unless one of the still
earlier names applied to the brown, white-tailed birds should prove available.
Lowe (1912, 205) found white adults much scarcer than breeding examples
in the brownish plumage at Orquilla Island in the Caribbean. Nicoll (1904,
588) collected 11 white examples and 23 dark ones from a colony at Little
Cayman. At the Galapagos, according to Ridgway (1897, 598), examples of
this booby with deep red feet and other evidences of maturity are all in gray
plumage, including even the tails, but Beck (1904, 8), whose experience at the
Galapagos is practically unparalleled, states that while the first 19 of the nest-
ing birds may, indeed, be of this grayish type, the twentieth will be white.
Beebe (1924, 313) likewise writes that at Tower Island there were both brown
and white Red-footed Boobies, the pure white birds numbering only about one
among forty. Other notes by Beck, still in manuscript and made during the
Whitney South Sea Expedition and on certain of his earlier voyages, state that
the same discrepancies and uncertainties are to be encountered throughout all
of the central and western Pacific archipelagoes. Between Ducie Island and
Matahiva, in the vast cluster of the Tuamotus, gray birds are prevalent, with
here and there a white tail and, somewhat less frequently, a bird in pure black
and white plumage. At the Revilla Gigedo group, Beck found by actual count
RED-FOOTED BOOBY 865
that 29 of the first 100 Red-footed Boobies seen were white, the others being
darker in various combinations. Flesh colors of this species have been noted
in the head matter, but I quote below Beebe’s (1924, 320) rainbow-tinted de-
scription of the grayish or brownish birds, as he found them nesting among the
trees of Tower Island, Galapagos:
The boobies were of a beautiful gull brown with much made-up bill and face. When one of
them looked down its long beak at me it reminded me more than anything élse of a circus clown
in full regalia. The bill was greenish-yellow shading into blue at the tip, the base of the bill and
narrow forehead pink, set off by jet black pigment behind. The skin around the eye was bright
blue grey, the eye itself cadmium-yellow, framed by eyelids of clear forget-me-not blue. When
the bright red feet were added to this, the harlequin effect was most striking. And with ic all, the
bird wore an air of anxious sobriety which heightened the bizarreness of the colour scheme.
As noted in Part I, this species is the only tree- and shrub-nesting booby and,
indeed, the only member of its family which has become a thoroughgoing
perching bird, entirely at home even among twigs and limbs swayed by a gale
of wind. Its distribution as a breeder is, therefore, determined not only by the
character of the ocean surface, and the presence of flying fish which make up
the bulk of its food, but also by the vegetation growing upon islands within
its possible nesting range. Ascension may once have furnished it a home, but
it can hardly have done so to any extent during recent centuries because of the
absence of trees and bushes. Moseley’s (1879, 563) record is clearly in error, for
he speaks of the nests as hollows in the guano. They doubtless pertained to
Sula dactylatra. Meliss (1875, 97) infers that it once inhabited St. Helena, which
is quite likely, though the destruction of the forest cover by goats within
historic times has been sufficient to banish it completely. At South Trinidad
we see such a process of change actually under way, for the Red-footed Boobies
still cling tenaciously to the fallen boles and broken stumps in the dead groves
of Caesalpinia. When the last of these has finally crumbled into dust, the bird
will perhaps become confined to the scrubby vegetation growing toward the
crest of this high island, and its numbers will undergo progressive reduction,
as they have no doubt for many decades past, owing to the dwindling number
of nesting sites. At any rate, a bird which has become so well adapted during
long ages for nesting in vegetation will hardly be likely to change its tastes
and build its nest upon bare rock.
Throughout the West Indies, and in the eastern tropical Pacific, we can see
further how environment becomes a factor in selective distribution. Bare
islands are of no avail to the Red-footed Boobies, even though the waters about
them teem with flying fish. The forests of Cocos and the scrub of the Revilla
Gigedos and the Galapagos are alike sufficient to attract and hold breeding
colonies; Clipperton Island, on the other hand, is avoided because of the absence
of suitable vegetation. At certain islands a single surviving tree may serve as
the last tenuous tie which keeps the Red-footed Booby among the local residents.
Such an instance has been pointed out by Wetmore (1925, 100) at Laysan.
A detailed search of the literature has yielded only a single report of boobies
of this species nesting anywhere other than in woody vegetation. The excep-
866 OCEANIC BIRDS OF SOUTH AMERICA
tion, which seems to me of particular interest, is that of Hanna (1926, 65), and
refers to birds of San Benedicto Island, Revilla Gigedo group. He writes:
‘‘The Webster's [Boobies] nested chiefly in the grassy areas and built a platform
one to two feet high of grass stems. . . . There were numerous birds of this
species on the cliffs, but they seemed to be only resting.”’
Such towers of grass culms must furnish the essential jumping-off place, for
Maynard (1889, 55) states that Red-footed Boobies cannot take flight from the
ground, and that they usually scramble along with the aid of wings and feet
until they can climb a bush and launch forth.
At nest-building time in most localities, according to the notes of Mr. Beck,
the Red-footed Boobies fly about looking for sticks and twigs, frequently
alighting in low bushes and on the ground to break off small branches which
are carried back and passed to a bird presumed to be the female, which remains
at the nest site and builds up the structure. Youthful boobies, continues Beck,
frequently make very small nests, through which the egg can be seen by anyone
looking up from below. Many twigs are dropped during the process of con-
struction, and piles of such material on the ground beneath, more or less ce-
mented together by the excrement of generations, indicate that sites are used
year after year for long periods. Frequently the nests of the Red-footed Booby
are built close to those of man-o'-war birds, with which it seems to live in
perfect harmony at home, even though this booby is a common victim of the
pirate over the surrounding sea. The trees or shrubbery furnishing the nesting
site vary, of course, in different localities; mangroves, sea-grape, West Indian
birch (Claphrium simarubra), palms, chenopodium bushes, and many other kinds
of vegetation are reported to be utilized.
As a rule only one egg is laid or, if there are two, one of the chicks comes to
an early—usually prenatal—end, as in the case of the Masked Booby. Fisher
(1906, 797) states that at Laysan Island the slightly hollowed platform of
twigs is lined with green leaves, which dry and shrivel up as incubation proceeds.
He found that he could judge rather accurately of the age of an egg merely by
observing the condition of these leaves. After the appearance of the egg the
boobies stand their ground tightly, and will ruffle up their feathers, utter harsh
cries, and lunge savagely with their bills, rather than be driven away. Peale
(1848, 274) states that nesting birds definitely aim their blows at the eyes of
intruders. Salvin (1864, 379) reports upon a colony on a cay off Belize, British
Honduras, where in April he found four or five nests in every tree. Because of
the clear sky, the lack of a sea breeze, and the thinness of foliage, the heat was
here intense, and the young boobies sat panting all day with their beaks open.
Some of them, apparently still more overcome, were resting with their heads
hanging straight down and their eyes shut. Such chicks looked dead, but when
stirred up they opened their eyes somewhat listlessly, and remained in the same
posture. To emphasize the normality of such odd behavior, I quote below a
similar observation by Maynard. Young birds in the Honduras colony were in
every stage of growth, and abundant data show that the breeding season 1s either
continuous or fitful, except perhaps toward the northern limit of the range.
RE D-FPOOTED BOOBY 867
Reithmiiller (1931, 144) writes that only newly hatched chicks of this species
are brooded by the parents. As soon as they become well covered with down
they are left entirely alone except at feeding time. Even during the night he
never observed an old bird guarding a downy chick at the nest. Maynard
(1889, 52), however, reports observations at variance with this, and states that
even when the young are as large as their parents it is usual to find one of the
latter during the day, and both at night, sitting beside them.
Maynard's excellent observations were made at Little Cayman, between
Cuba and Jamaica. Here, in March, he found the Red-footed Boobies nesting on
large flat-topped sea-grape trees. The colony extended along the shore to the
edge of a mangrove swamp into which, however, it penetrated for only a
short distance.
The nests were very numerous, five or six being placed on every tree; as this locality had been
occupied for many years, a large number of the trees had been killed by the droppings from the
birds, and on the long, naked branches, were perched thousands of Gannets, sitting side by side
in rows, a motley array, consisting of all stages of plumage, from the newly fledged, wholly dark
brown young, to the creamy dress of the perfect adult. Almost every nest was tenanted by a young
bird, usually well grown, clad in a beautiful garment of long, pure white down, from which pro-
truded the dark brown wings and tail, while the air was filled with hundreds of birds, departing
and returning from fishing excursions, giving utterance, as they came and went, to harsh cries
that were answered by those perching. . . .
The most remarkable thing about this gannetry, was its situation in such close proximity,
not only to the houses, but to the cocoa-nut grove in which the inhabitants were constantly at
work, for the birds could have retreated to the fastnesses of the mangrove swamp, where they
would have been perfectly secure from intrusion. The people, however, never disturbed the birds
much, at most only taking a few eggs at the beginning of the nesting season, for cooking. . . .
The presence of the Gannets was regarded favorably, as they not only killed the trees, thereby
opening spaces in which cocoa-nuts could be planted, but also greatly enriched the soil.
Maynard states that the nests are ill-constructed fabrics, resembling those of
the night heron (Nycticorax). Egg-laying at Little Cayman begins about New
Year and continues at least until March. The newly hatched bare chicks are
killed very quickly if they become exposed to the direct rays of the sun. Within
ten days, however, they are well covered with down. Young of all sizes cling
to their boughs and twigs tenaciously and the older nestlings climb about
freely, aiding themselves with the bill but apparently not employing the wings
for this purpose. The nestlings
. are fed at first by true regurgitation, that is the fish eaten by the parents is converted
into a peculiar glairy fluid which is given to the young. The old birds introduce the terminal
portion of the bill into the mouths of their offspring and the liquid is literally poured down their
throats. Later the fish is given to the young in half digested fragments and in the same manner,
then the size of pieces is gradually increased, until finally whole fish are disgorged for them. In
all cases the fish are swallowed by the adults and so carried to the gannetry.
The young remain in the nests until two-thirds grown, then leave them and perch on the
branches near. Here they remain until wholly fledged, and evidently for some time later. In fact,
they appear to fly with considerable reluctance, sitting on the branches long after they are capable
of using their wings. I have often taken such birds in my hands and by tossing them gently into
air, induced them to take wing, and in all cases, when once launched, they would fly readily,
frequently keeping in air for some time. On several! occasions, I have seen the adult Gannets trying
to compel their young to take wing, by flying against them in order to push them from the branch,
868 OCEANIC BIRDS OF SOUTH AMERICA
the young remonstrating by struggling and screaming lustily, but the parent would invariably
accomplish its object after a trial or two.
The cry of the young to the parents, when they desire food, is a kind of chatter, much like that
emitted by young herons, under similar circumstances. When annoyed they will give a harsh
squak and at the same time will launch out the bill at the intruder. As in all birds, there is a large
amount of individual variation in respect to disposition; some being very irritable, and these
would even attempt to reach me with their bills when I was walking along the ground; others
were good natured from the beginning. Such would even permit me to stroke and pet them as
they sat in the trees or on the nests. The one that I kept at my house and that I afterwards carried
to Kingston in company with a young Man-of-war, was very tame and soon learned to recognize
me, evincing his enjoyment upon being petted by a tremulous motion of the head.
With reference to behavior of adults Maynard writes:
I could climb a tree on which a number of nests were placed, some of which contained birds
that were incubating, without them taking flight; even when I was within arm's length of them
they would not move, but would sit perfectly quiet, regarding me with attention. When I stretched
out my hand toward them they would not even attempt to escape, but would merely bow the
head downward, nearly touching the breast. They uttered no sound at this time, neither did they
evince any sign of hostility. I was so completely deceived by the amiable and dove-like behavior
exhibited by the first bird that I encountered, that J unhesitatingly reached out my hand to feel
beneath her in order to ascertain upon what she was sitting. She maintained her state of composure
until my fingers were within a foot of her, when without a moment's warning, she launched out
her bill fiercely, seizing my hand with a vice-like grip. Then she almost instantly jerked back
her head without opening her bill, thus cutting my hand badly above and below, with the sharp,
serrated edges of the mandibles.
I did not fail to profit by this hint, and ever after carried a short stick, then when I wished to
find out what a Gannet had in its nest, would push the occupant off with this weapon, at which,
however, the birds were too sensible to strike. When thus forced to vacate the nest, they would
seldom fly, even when there was only an egg, and never, if there were a newly hatched young.
They would, in these latter named cases, simply retreat a few feet along the limb on which their
domicile was placed, then would return as soon as I removed my stick and bending down, would
touch their helpless offspring with the tip of their bill, repeating this several times in succession. . . .
The adult Gannets give harsh cries when annoyed, and upon returning from a fishing excursion,
just before alighting, they give a series of nearly continuous croaks. Both young and adults sleep
by lying down upon whatever they may be perching, often with the head hanging directly down-
ward, the neck stretched at full length. So singular is this attitude, that the first time I saw an
adult in this position, I was so sure that it was dying, that I went to it and caught hold of the
head, before it was aware of my presence; the result was a surprise for both of us, the Gannet
recovering with such marvelous celerity, as to astonish me, and it, in turn, retreated screaming,
badly frightened at this unceremonious awakening.
Maynard found that the Red-footed Boobies would return to their colony
in files or irregular wedges, made up of from three or four to a score of birds,
and that they invariably came to their nests directly from the sea. In other
words, they would never cross any part of the island either when setting forth
empty or coming back well laden with fish. Their invariable custom was to
skirt the shore at a considerable distance, and then turn at a right angle when
they came abreast of their particular nests. This curious predilection gave
every advantage to their enemies, the man-o'-war birds, which regularly lay
in wait for the boobies between their colony and the open sea. A victim was
usually singled out and harassed by from two to eight or ten man-o’-war birds,
which frequently seized it by the tail or wings in the effort to make it disgorge.
RED-FOOTED BOOBY 869
Maynard believed that if the boobies could only overcome their disinclination
to fly across the island they would circumvent their principal enemy, because he
noticed that no man-o’-war bird ever pursued a booby which had once gained
a position above the land.
At Tower Island in the Galapagos, Beebe (1924, 313) observed that these
boobies flew steadily and rapidly, usually close to the water and chiefly in
flocks of from eight to forty. Their flight, like that of the pelicans, was a
rhythmic flap-flap-flap-flap-soarrrrrrrrrrr, flap-flap-flap- flap soarrrrerrrrrr. Gif-
ford (1913, 88) writes:
The flight of the Red-footed Booby is more graceful than that of the Blue-faced, . . . , and
somewhat resembles that of a large shearwater. When in the vicinity of Cocos Island and of
Clarion Island, flocks of Red-footed Boobies were seen flying away from the islands in the morn-
ing and towards them in the evening. The flocks contained from six to fifteen birds. The birds
fly with the same gentle, wave-like rise and fall that characterizes the flight of other members of
this genus. The wing-strokes occur on the rise; on the downward swing the bird sails, in calm
weather often going several yards very close to the surface of the water. The members of a flock
are practically synchronous in every action.
According to Gifford, the Red-footed Booby dives in the same manner as the
Blue-footed, plunging from heights up to 10 meters or thereabouts, and entering
the water with wings half closed and held rigidly. On one occasion at the
Galapagos he saw these birds catch flying fish on the wing by swooping into
schools that were skimming along above the water. Flying fish are the best
known food of the species, and Wilson (1904, 211) refers to a 15-centimeter
example in the throat of a bird. Fisher, however, found many cephalopods in
stomachs examined at the island of Laysan, and Beck's notes likewise report
that flying fish and squids were present in equal quantity in the stomachs of
Pacific specimens inspected by him. Beck confirms Gifford’s observations that
flying fish are sometimes captured in the air, but he adds that the greater part of
them are taken by diving at times when the unfortunate fishes are being harried
and driven to the surface by larger predal fish below. Beck writes, furthermore,
that these boobies regularly fly to distances of more than 50 kilometers from
their nests on their daily excursions. All observers appear to agree that they
are not given to plunging into the coastal breakers of their home islands, as
the Brown Boobies frequently do, but that they head at once for ‘‘blue waters.”’
Squids come to the upper layers of the ocean chiefly at night, and their
presence in the stomachs of surface or aérial animals is usually an indication
that such captors are more or less nocturnal or crepuscular in habit. This
applies to the Red-footed Booby, for at whatever island it lives it is notorious
as the last of the resident sea birds to calm down in the evening. The members
of a colony also come and go during moonlit nights, and at the same time they
appear to spend more of the daylight hours asleep than do any of the other
species. Lowe and Kinnear (1930, 184) quote the following paragraph from
entries made at South Trinidad, during July, 1910, by Dr. E. A. Wilson:
These Gannets were by no means difficult to capture by hand. They evidently have no enemies
at all on the Island for they go to sleep with their heads under their wings, either alone on a dead
870 OCEANIC BIRDS OF SOUTH AMERICA
tree trunk or branch, or in small colonies of half a dozen together on the evergreen bushes high
up on the hillside. Here and there one found them sleeping in the hot sun in broad daylight—it
was very easy to crawl quietly up to one and seize it by the neck as it awoke.
In correlation with such partially nocturnal habits, the Red-footed Booby
apparently has the largest eye of any member of its family. This character has
perhaps not previously been pointed out, but it shows well in all good photo-
graphs of the species, in comparison with those of other boobies, and is determin-
able even in the size of the ocular orifice of dried skins. The colors of the iris
in relation to age, sex, phase, race, range, and individual peculiarity have a
significance not yet fully worked out. They have been variously recorded as
white, blue, gray, brown, and yellow.
THE CORMORANTS
FAMILY PHALACROCORACIDAE
The cormorants or shags are of almost cosmopolitan distribution but, except
toward the northern and southern extremities of the world oceans where dis-
tance lessens with the converging of the meridians, they have not generally
established themselves at islands remote from the continents. In other words,
they are all littoral rather than pelagic sea fowl and even the southern circum-
polar forms, which inhabit many of the pan-antarctic islands from South
America across the Atlantic and Indian Oceans to the outliers of New Zealand,
are highly sedentary. It would be reasonable to suppose that the meteorology
of the west-wind zone explains the present distribution of the latter group, and
that the direction of dispersal has been from west to east.
The only other cormorant which has attained notable oceanic isolation is
the peculiar flightless species of the Galapagos.
In the northern hemisphere there are many cormorants of a common type
which have taken to the interiors of the great continents and have thus become
inland no less than coastal birds. Some of these have also penetrated southward
into Africa and Australasia. South America, however, has but one species of
this stamp, namely, Phalacrocorax olivaceus, which is doubtless an immigrant
from North America and which, like its closest of kin, is equally at home in
either salt water or fresh. The Flightless Cormorant, despite the profound
structural gap which separates it from any other member of the family, also
has many earmarks of the widespread northern-hemisphere birds which, for
want of a better term, may be called the carbo assemblage. In the Hesperidian
environment of the Galapagos Archipelago, where for long ages the climate
has been bland and uniform, food abundant, competitors limited, and pre-
dacious enemies wanting, Nannopterum has suffered no phylogenetic inhibition
against the trends which have led toward increase of size, loss of flight, and the
development of a curious hair-like plumage. Asan evolutionary product it may
be fairly compared with the Great Auk among the Alcidae, although its degree
of relative morphological departure is greater.
THE CORMORANTS 871
The remaining cormorants of the South American region are of totally
different heritage from either Nannopterum or Phalacrocorax olivaceus. Leaving
out of consideration the question of the ultimate origin of this ancient family,
we may feel reasonably sure that the species mentioned below have no near
relationship with any cormorants of the northern hemisphere. They are of a
different aspect as regards plumage-pattern and minor details of structure. They
are almost exclusively marine, and the historic path of their invasion of South
American coasts has undoubtedly led from south to north.
First as the Red-footed Cormorant (Phalacrocorax gaimardi), a gray and
peculiarly marked species which stands alone. Its closest relative is apparently
Phalacrocorax punctatus of the New Zealand region, and nothing is known about
its primordial introduction into South America. It is possible, of course, that
both the New Zealand and South American species are peripheral relics of some
form of cormorant that long ago worked its way southward along Pacific sea-
coasts from the holarctic region. Of at least equal weight is the fact that the
present range of gaimardi is directly to leeward of that of punctatus in the west-
wind belt. Even the breadth of the South Pacific might not form an insuperable
barrier to direct accidental transportation from west to east in high latitudes.
In any event, the present distribution of the Red-footed Cormorant extends from
Atlantic Patagonia northward along the west coast through part of the Hum-
boldt Current zone.
The other South American cormorants are all obviously of pan-antarctic
origin. They are white-breasted birds, with caruncles at the base of the bill,
and they comprise the two species of ‘‘blue-eyed shags’’ of the southern tip of
the continent and adjacent antarctic coasts, a Falkland-Fuegian species (magel-
lanicus), and an endemic Humboldt Current species (bougainvillit).
Because of the geographic relationships and consanguinity indicated, I have
departed in the biographies from the systematic order of Peters (1931, 90), who
separates the southern-hemisphere cormorants by unnatural lines of cleavage.
The following arrangement of South American cormorants throws the species
into taxonomic groups, and indicates the probable affinities of Nannopterum
with birds of the northern hemisphere.
1. Phalacrocorax gaimardi
2. Phalacrocorax atriceps
Phalacrocorax albiventer
Phalacrocorax magellanicus
Phalacrocorax bougainvillii
3. Phalacrocorax olivaceus
Nannopterum harrisi
The cormorants exhibit a certain fundamental sameness in their behavior-
patterns, thus demonstrating the deep-seated genetic composition in the an-
cestry of all. Portielje (1927, 107) has made observations on captive Common
Cormorants at Amsterdam, pointing out fixed responses that mostly apply
872 OCEANIC BIRDS OF SOUTH AMERICA
Fic. 70. Feathering of face and gular sac, and cross-section of the maxilla, in five species of
South American cormorants. The sketch beneath each head shows the base of the sac of the re-
spective species in ventral aspect.
Reading from left to right: upper two, Phalacrocorax olivaceus olivaceus and P. gaimardi; middle
two, P. magellanicus and P. bougainvillii; lower drawing, Nannopterum harrisi. All represent males.
The affinity between magellanicus and bougainvillii is clear; that between olivaceus and N. harrisi
is suggestive; gazmard: is highly distinctive.
equally to such South American species as have been closely watched in the
field. The birds are particularly lively, for example, at the beginning and end
of the day. They dive and plunge in zigzag lines. In early spring the female
seems to take the initiative in expression of courtship mannerisms about the
time that both sexes assume the details of pre-nuptial plumage. Simultaneously
they develop a new vocal repertory. The male is the first to begin to toy with
THE CORMORANTS 873
nest material, which it passes to the female, and the latter utters the mating
call while arranging it. In the reaction of invitation to her mate, the female
spreads the tail like a fan, bends it upward and forward, extends the head
upside down along the back, at the same time swinging it from side to side,
and shuffles the wings. The male puffs out the plumage of the head and neck,
and distends or inflates the gular sac. Both sexes hold the beak widely open
during much of their display. As noted elsewhere, many of these gestures are
strikingly similar to those of petrels and their kin.
Lewis (1929) has published an exhaustive study of the Double-crested Cor-
morant (Phalacrocorax auritus auritus), which is a suggestive guide to observers
of any other species. Both he (76) and Crisp (1860, 259) describe the use of
the uropygial gland in the preening process, the latter author stating that the
crown of the head, as well as the beak, is frequently applied to the nipples of
the gland.
During long flights cormorants commonly hold their bills agape, as though
increased activity of respiration were thus aided. The external nostril is, of
course, almost obliterated among these birds. The osseous canal is also of very
slight diameter, but the narial chamber is in free communication with the
mouth (Ewart, 1881, 455).
Numerous authors have alleged that cormorants do not employ their wings
for swimming beneath the surface, and F. H. Salvin (1891, 150) has shown that
a captive which had had an injured wing amputated continued to catch fish as
readily as its fellows. Be that as it may, we now know from abundant evidence
that many if not all cormorants literally ‘‘fly’’ beneath the surface in the course
of their longer plunges. Clay (1911, 138) has taken several Brandt's Cormorants,
of western North America, from fish traps set at depths of 40 meters, and relates
testimony concerning even deeper dives.
Cormorants have notoriously enormous appetites and rapid digestive powers,
both traits of fish-eaters in general. Mattingley (1927, 182) has found that
examples of several Australian species ingest an average of slightly more than
half their weight per day. The body temperatures of various Australian cor-
morants were found by White (1918, 214) to range between 40.7° and 43.1° C.
RED-FOOTED SHAG
Phalacrocorax gaimardi
Pelecanus Gaimardi ‘‘Garnot'’ Lesson, 1828, Man. d'Orn., 2, June, p. 373 (Callao Bay, Peru).
Names: Gray, or Scarlet-foored Cormorant. The South American names are numerous and
include ‘‘Chuita,”’ ‘‘Chiquitoy,’’ ‘‘Patillo,"’ ‘‘Pato de Mar,"’ and “‘Lile’’ or ‘’Pajaro Lile.”” A
synonym of the specific name is cérriger.
Characters: A gray-plumaged cormorant with an elongate white patch on each side of the
neck, the naked skin of the face orange-red, and the feet coral-red.
Adults (sexes alike): Head, neck, lower back, rump, upper tail coverts, and quills of wing and
tail dark neutral gray; ventral surface, caudad from throat, somewhat paler (deep neutral gray);
an elongate white patch on each side of the neck, placed somewhat toward the mid-line; a few
short white hackles in the post-ocular region of the head; upper back, wing coverts, and scapular
feathers bearing conspicuous sagittate subterminal markings of silvery gray, distal to which each
874 OCEANIC BIRDS OF SOUTH AMERICA
feather is broadly bordered with blackish; the size of the gray areas increases caudad, and on the
longer coverts occupies the greater part of each feather. Iris green, surrounded on the lid by 16 pale
blue, jewel-like spots, 10 above and 6 below the eye; bill distally horn-yellow, blending into orange
toward the base; gular sac orange-red; legs and feet coral-red.
The horny mandible of this cormorant extends caudad quite to the angle of the mouth. Among
other South American species a soft integument covers the mandible at least as far forward as the
position of the eye. The arrangement of feathering about the eye, lores, and gular pouch is like-
wise peculiar, although approached to a certain extent in P. magellanicus.
10 males from Peru and Chile: wing, 240-254 (248); tail, 92-101 (97.2); exposed culmen, 55-
62 (58.2); tarsus, 50-54 (52.2); outer toe and claw, 91-98 (94) mm.
8 females: wing, 232-245 (239); tail, 92-103 (97.5); exposed culmen, 55.5-62 (58.8); tarsus,
50-54 (51.4); outer toe and claw, 89-96.5 (91.6) mm.
Specimens of this cormorant in the flesh weighed between 1304 and 1417 grams (Coker,
1919, 480).
In immature examples the plumage is generally brown, the wing coverts and under parts being
mottled with brownish white; the white patches on the neck are always at least faintly indicated.
Birds in juvenal plumage are paler, and have whitish throats and a conspicuous sprinkling of white
plumules on the center of the throat and the sides of the neck. The down of nestlings is largely
brownish drab.
Eggs number 2, 3, or 4, and are usually of somewhat elongate form. The color of the shell is
pale blue, more or less concealed by an unevenly distributed white chalky coating. Two examples
recorded by Coker measured 63 x 38 and 64 x 39 mm.
Distribution: Coasts of southern and western South America, from the Macabi and Guafiape
Islands, Peru, southward to the Strait of Magellan, and northward along the Atlantic coast to the
vicinity of Puerto Deseado, Argentina. The species seems to be rare in the Strait of Magellan,
although it was described from there (as Phalacrocorax cirriger King) in 1829. Its breeding sites
include both islands and cliffy parts of the continental coast.
The Red-footed Cormorant or ‘‘Chuita’’ is recognizable from its scarlet feet
and face, its gray plumage, the elongate white markings on the sides of its neck,
and its high-pitched chirping voice which seems very ‘‘unseabird-like.’’ It is
peculiar to southern and western South America, but its blood relationship
seems to be closer with a New Zealand cormorant (Phalacrocorax punctatus)
than with any species of the New World.
The “Strait of Magellan’’ or “‘Chile’’ are often cited as the type locality of
this cormorant, but Garnot’s account leaves no doubt that the birds upon which
the original description and plate were based came from central Peru. He
states, ‘Ce beau cormoran habite les bords de la rade Callao,”’ and that it is
particularly common on the rocks of San Lorenzo Island. Its distribution ap-
pears not to carry it as far as the northern end of the Humboldt Current. There
are thus no records for the Lobos Islands, though on February 2, 1920, I saw
two examples off Macabi Island (7° 50’ S.). Only slightly to southward, at
Guafiape (8° 36’S.), it isan abundant resident. From here it remains a common
bird down the west coast at least as far as Chiloé Island. Mr. Bullock found it
abundant and nesting at Mocha Island, its homes being built on ledges of prom-
ontories or rocky islets against the bases of which the sea pounded. On
November 20, 1932, he took five sets of three eggs each on a headland known
as Punta Cuervos.
Throughout the Magellanic waterways the Red-footed Shag is relatively
scarce, but it appears again in numbers along the Atlantic coast of Patagonia.
RED-FOOTED SHAG 875
On May 11, 1915, Beck found the species plentiful at the mouth of the Rio
Santa Cruz, noting in his journal that he had last seen it at Ancad, Chile. To
northward these cormorants have been recorded from Port San Julian (Hellmayr,
1932, 296), and as breeding on the Isla del Cafiadon in the estuary of the Rio
Deseado (Renard, 1931, 412; Doello-Jurado, 1917, 11). The last-named author-
ity found about 250 nests containing eggs and fledglings during February, 1916.
Renard reports that the breeding season was still in full swing here at the oppo-
site season of the year, in July.
Two factsare noteworthy: first, that the Chuita isa strictly continental cormo-
rant, unknown from the Falklands, the outlying Fuegian islets, and the oceanic
islands off the Pacific coast; and second, that it is a distinctly sub-antarctic in-
trusion into the Humboldt Current zone, which it does not occupy in full.
During my own field work and that of Mr. Beck, nesting Chuitas were
encountered at more thana score of cliffy insular and mainland localities between
North Guafiape Island and the rocks off Anctd. It is safe to assume that not
one of the Peruvian guano islands lacks a few pairs engaged in some part of the
reproductive process during every month of the year. South Guafiape, the
Huaura group, the Pescadores, San Lorenzo and its outliers, the Chinchas and
Ballestas, San Gallan, Vieja, and Santa Rosa were all centers of abundance.
At South Guafiape this species shared the whole periphery of the island with
Inca Terns, leaving the crown exclusively to the Peruvian Boobies. In a cave
on Guaca, of the Pescadores, and in the gorge of a neighboring split islet known
as San Pedro, the Chuitas were nesting so thickly during December, 1919, that
they formed practically a colony, which is exceptional on the part of this ‘‘her-
mit’’ species. Furthermore, in the largest of the sea caves at North Chincha
I found several nests only a few meters apart.
The notes of Paessler (1909, 102), in conjunction with numerous specimens
in the American Museum Collection, indicate that the status of the Chuita
along the desert coast of Chile is similar to that in Peru.
Coker (1919, 480), whose important studies of the guano birds I have con-
stantly drawn upon, has given an interesting ecological comparison between
the three species of cormorants inhabiting the Peruvian littoral. These are the
Guanay (Phalacrocorax bougainvillit), the Cuervo or Bigiié CP. olivaceus), and the
present species, which he calls the ‘‘Patillo.’’ He writes:
The three species of cormorants above described offer a striking illustration of the adaptability
of nature. Three birds closely related, within the same genus in fact, dwelling in the same localities
and not differing greatly in size, afford such striking contrasts in habits and appearance, as may be
expressed in the following analysis.
Social habit.—The one herds in enormous flocks, another forms small groups, while the third
is never seen except singly or in pairs. Of the two extremes, the patillo is always thought of as
an individual, even though chance might bring several birds together, but the individuality of the
guanay is always lost in the multitude.
Breeding habit.—The one nests crudely on the broad expanses of the island tops, another on the
rough outlying rocks, while the third finds isolated homes on the cliffs or in the caverns where it
constructs strong and secure nests of variously collected materials.
Feeding habit —The one flies out in great flocks to swim on the surface and dive for prey in the
schools of surface fishes; another watches from its low perches or dives down to capture the fishes
876 OCEANIC BIRDS OF SOUTH AMERICA
of the bottoms near shore; while the third often makes long single flights before diving in search
of eels or other fish or for nest-building materials.
Voice.—The one utters a distinctive croak, the second makes a harsh guttural grunt, while the
third has a high-pitched voice of the timbre of a song bird.
Color —The guanay has a shiny black back and glossy white breast, the cuervo is dark and of
almost uniform coloring, and the patillo is of generally variegated color with white stripes and
scarlet feet.
The patillo (P. gaimardi) is rather remarkable among cormorants for the entire absence of any
disposition to gregariousness, and it is the most specialized of the three in its well-developed habit
of nest construction and its instinct of protection of young, shown in the choice of location for
the home.
Without wishing to gainsay Coker’s correct understanding as to the essen-
tially solitary predilections of the Chuita, I must report that it does, on occa-
sion, form bands or small flocks. Several such are mentioned in the literature,
as by Cunningham (1871, 365). Mr. Jaques observed “‘strings of as many as
twenty” in the bay of Callao, and Beck saw larger aggregations at Corral,
Chile. On January 24, 1920, between Salaverry and the Guafiape Islands, I
noted many groups of from 6 to 20 on the ocean, and two compact flocks of 16
and 30 birds, respectively, in flight.
The Chuita is a familiar feature of the seascape, found equally along the
coastal steamship lanes offshore and on every buoy and lighter in the west
coast roadsteads, but never entering fresh water.
One meets them floating lazily yet watchfully on the water, occasionally flapping wings or
ducking beneath the surface as enjoying a bath, or making a sudden dive for prey to come up with
a fish or a wriggling eel, which is swallowed only after a little struggle. They seem to be peculiarly
successful eel catchers, as I have many times seen them with such prey. . . .
Their flight is characteristic—low and straight. The appearance of intentness in flight is
accentuated by the series of three conspicuous streaks in series; the orange and red bill, the white
neck stripe, and the scarlet legs and feet lying straight back beneath the tail. The whole manner
is that of one with predetermined course eagerly seeking a certain destination. I never saw one
turn its head aside, as the swift gannet will do to investigate an observer. A very slight bend of the
neck is sufficient for reconnoissance or for determining a change of course. Their short wings make
flight a more strenuous and absorbing affair than for the gannet. Thus, as I have counted them,
the wing strokes of the patillo, a minute, are from 250 to 300, as against 160 to 170 for the gannet,
150 to 190 for gulls of different species, and 140 to 150 for the pelican.
The home of the patillo is on the bold cliffs and in the caverns, and the body color would
give effective concealment against the rocky walls except for the brighter markings of the legs and
the neck of the adults. As one approaches an apparently bare rocky wall rising above the surf,
small bright red spots in pairs with three or four rays may be distinguished against the gray back-
ground of the rocks. If low down, they may easily be mistaken for starfishes or the red-legged
crabs left by the tide, but these are the legs and feet of the patillo. When one is a little closer a
white spot is made out some distance above the red. The eye and the imagination may then fill
out the form of the bird between the white neck stripes and the scarlet feet. The young birds
against a rocky wall are almost indistinguishable even when one knows the exact location of the
nest. When in flight, the bright skin colors and the neck stripe, together with the characteristic
manner of flight, makes this bird most easily recognized even at a great distance.
A surprising characteristic of the patillo is its cry, which is entirely unlike that of the ordinary
cormorants that utter a coarse grunt or croak. When flying from the nest it often gives a high-
pitched repeated chirp, somewhat like the note of the sparrow. This undoubtedly accounts for
the common name sometimes used, ‘‘chuita,’’ a name entirely more suggestive of a peewee than
of a cormorant (Coker, 1919, 480).
RED-FOOTED SHAG 877
The nest, built on some small bracket or ledge of a cliff, is composed of a
variety of seaweeds, of many leathery worm tubes, of straw, feathers, string,
or any other accessible and suitable material. The worm tubes are especially
important because they bind together the looser materials, giving the nest
strength and stability in its precarious position. Coker writes:
One nest was weighed, although, unfortunately more than a third of the material had been
lost in removing it from the side of the cliff. The amount saved was found to weigh 8 pounds, and
the complete nest must have weighed over 12 pounds. It was composed of Ulva and of various
brown and red seaweeds, but the bulk of the total material was a chocolate brown weed with
white tips, probably Corallina chilensis. The worm tubes, however, formed a very considerable
portion, constituting 234 pounds or one third of the material saved.
From the rocks of Central Chincha in October, 1919, I could watch individual
Chuitas diving for both food and nesting materials. When gathering the latter
they would plunge repeatedly to the bottom in depths of from 8 to 10 meters,
emerging each time with a larger bunch of seaweed and tubes of marine worms
in their bills. How they kept a grasp on the accumulated spoils is a mystery,
but they would not fly to the chosen home-site until they had garnered a gener-
ous billful.
All observers who have sometimes found more than two eggs in a nest agree
with me that only two black downy young are reared. The nestlings seem more
alert than those of most cormorants, soon learning to stand up on straight legs
on their trampled mattress, and moving their heads with rapid, nervous, peering
gestures.
The breeding season seems to be absolutely continuous. At the Pescadores
Islands, in December, I saw fledglings in flight while many adults were still
collecting nest lumber and whizzing across the water with their bills full. At
the same place in April Beck found the same medley of behavior, as Pickering
also did at San Lorenzo Island (Cassin, 1858, 376).
Since the Chuita is of no value as a producer of guano, because of its habit
of nesting on the cliffs and in the caverns, neither law nor sentiment protects it,
and it therefore suffers the plight of a preferred ‘‘game bird’’ of the maritime
Indians. I was once served with boiled nestlings, but the dish left me with no
taste for more. Two destructive pieces of apparatus seem to be part of the
habiliments of all the guano island guardians—men who would go to almost
any length to see that no harm came to the commercially valuable birds under
their special charge. One of these is a pole of bamboo or sugar cane, with a
fishhook lashed to the end; the other is the long surcingle of webbing which
supports their trousers. With the hook they yank the unfortunate young
Chuitas from their ledges, and with the strap they make a noose for hauling
penguins out of their holes. Singly or in combination, indeed, the pole and
strap are put to a variety of nefarious purposes, but the average inaccessibility
of Chuita nests is sufficient to save the species from serious depletion.
Other than men, the Chuitas have no apparent enemies. Possibly their
ectoparasites may at times bring about a natural reduction in numbers, for of
these cormorants in Chile, Gay (1847, 489) has quaintly written, “‘Se empiojan
878 OCEANIC BIRDS OF SOUTH AMERICA
y mueren muchisimos por agosto’’—in August they get lousy and perish
mightily!
Regarding their food, I have quoted above the observations of Coker. It
appears, however, that the famous “‘anchoveta’’ (Engraulis ringens) is a staple
of this as of so many other sea birds along the coast of Peru. Four Chuita
stomachs that I sent to the United States Biological Survey contained only this
fish—one of them 28 examples—together with a few parasitic isopods (Anilocra
plebia).
Tue Bruz-Eyep Suacs
The blue-eyed shags—more exactly blue-eyelidded, for the iris is brown—
comprise a circumpolar group of rather sedentary cormorants, the interrelation-
ships of which are still very imperfectly understood. In the Pan-Antarctic Zone
there are about a dozen distinct forms, which have been variously listed as
species and subspecies. A conservative taxonomic arrangement would admit
perhaps four or five species, but future research may revise such a figure down-
ward. Outside the limits of sub-antarctic surface waters are certain related or
derived cormorants, of which the famous Guanay (Phalacrocorax bougainvillit)
of the Humboldt Current is presumably one.
The typical pan-antarctic representatives, to which we shall here confine
our attention, have been distinguished by the subgeneric name Leucocarbo of
Bonaparte. Of them Falla (1932, 144) has recently written:
The cormorants inhabiting high southern latitudes and grouped in three areas, namely, South
America and its sub-antarctic quadrant, the South Indian Ocean, and the sub-antarctic coasts and
islands of New Zealand, are generally regarded as distinguishable from other cormorants by well-
marked external characters shared by most of them. These characters are the fleshy ring of blue
skin surrounding the eye, the frequent presence of dorsal and alar patches of white feathers, the
brightly metallic plumage of the upper parts, and flesh-coloured feet. This last point, the coloura-
tion of the feet, has been a source of much confusion in descriptions, and most published coloured
plates are unreliable in this respect. It would now appear that the feet of blue-eyed shags are all
some shade of pink in life. It has recently been accurately reproduced by L. H. Matthews (1929,
pl. XLVID) in the case of P. georgianus. In dried skins the feet of all the species I have examined
dry to a rich orange brown, which is perhaps responsible for the frequent occurrence of *‘feet
orange’’ in descriptions. Literature of this group by various writers during the nineteenth century
is not always reliable, on account of inaccurate determination and lack of comparative material,
a disadvantage that still persists to some extent.
The first known of the blue-eyed shags was Phalacrocorax carunculatus, de-
scribed by Gmelin in 1789. It is supposed to be confined to New Zealand and
its outlying sub-antarctic islands. In its general plan of color and pattern,
however, it closely resembles the South American members of the group, and
it is noteworthy that the old-time sealers applied one name, ‘King Shag,’’ to
both Old- and New-World representatives.
In the American quadrant blue-eyed shags are of antarctic as well as sub-
antarctic range. Indeed, in the Antarctic Archipelago they nest as far south-
ward as any birds except, perhaps, the Emperor and Adélie Penguins and the
South Polar Skua. The shag of this antarctic district 1s Phalacrocorax atriceps,
THE BELWE-EYED:SHAGS 879
which also reaches South Georgia and continental South America and which,
according to Peters (1931, 92), is practically circumpolar, with a subspecies at
Macquarie Island, southwest of New Zealand. This allegation at least tends
to cast suspicion upon the specific distinctness of the shags inhabiting the Crozet
Islands and Kerguelen, which are stations of similar latitude along the west-
wind route of avian distribution.
A second American species of the assemblage is Phalacrocorax albiventer, of
Tierra del Fuego, the Atlantic coast of Patagonia, and the Falkland Islands.
No subspecies of this cormorant have been described, but it has been much con-
fused with one or more of the races of P. atriceps, particularly with the form
inhabiting the Fuegian islands, where the ranges of albiventer and atriceps over-
lap. Very recently, Reynolds (1935, 81) has written as follows:
I cannot distinguish between [the birds of] such colonies as that breeding in the centre of
Tierra del Fuego (Lake Yewin) and the colony north of Hermite Island. I, therefore, do not see
that P. albiventer is segregated in breeding colonies anywhere on Tierra del Fuego. . . . The only
Cormorants which I am inclined to recognize for Tierra del Fuego are the three species listed above
(olivaceus, magellanicus, atriceps|, with the possible inclusion of P. a. albiventer of the Falklands as
either a rare vagrant or as a poorly segregated race, which, if it breeds at Tierra del Fuego, mixes
with the typical form. The records of P. a. albiventer from Tierra del Fuego should, I suspect, be
regarded as variations of P. a. atriceps (age and season?).
Reynolds states, furthermore, that among examples of P. atriceps in all the
Fuegian breeding colonies there is much variation in the proportionate areas
covered by the dark dorsal and the white ventral plumage on the side of the
neck. The condition, as will appear below, is concerned with characters sup-
posed to distinguish atriceps from albiventer.
Now, while the remarks of Reynolds, who has had extraordinarily great
field experience, serve to point out the difficulties of the problem, I cannot
believe that there is but one species of blue-eyed shag in the Fuegian region.
Typical examples of what I consider to be two species were, for example, shot
on the same date by Beck at Magallanes in the Strait of Magellan. To be sure,
the species atriceps and albiventer are exceedingly similar birds. Their differences
are of the grade ordinarily marking subspecies, but the fact that the two appar-
ently share a common breeding ground in southernmost South America makes
it necessary to regard them as more distinct than they superficially appear.
The real differences between closely related species doubtless lie more partic-
ularly in physiological composition, in metabolism, in tolerances and other
reactions to environment, than they do in the color and pattern of their plu-
mages. It is altogether likely that atriceps and albiventer have a strongly marked
divergence in behavior which has not yet been adequately pointed out.
The two species, as represented by topotypical birds in the Brewster-Sanford
Collection (viz., albiventer from the Falkland Islands, atriceps from the Strait of
Magellan) show no detectable differences in average dimensions. The principal
visible distinctions between them are reduced to two: (1) the line dividing
dark from light plumage on the side of the head is high in africeps, while in
albiventer it cuts across the cheeks; (2) atriceps acquires after the breeding season
880 OCEANIC BIRDS OF SOUTH AMERICA
a squarish patch of white feathers on the back, while in albiventer this mark
never appears. In the light of present probabilities, I am therefore treating
the South American blue-eyed shags as representing two species, realizing at
the same time that it may never be possible properly to allocate some of the
earlier published observations between them.
The typical race of Phalacrocorax atriceps is continental and sub-antarctic,
but it seems highly probable that there are also two or more American antarctic
subspecies. The shag of South Georgia, for
instance, 1s somewhat intermediate between
atriceps and albiventer with respect to the
line separating black dorsal from white ven-
tral plumage. In the acquisition of a white
patch on the back it agrees wholly with
atriceps, but it has a much shorter bill and
larger caruncles than the South American
form. It was originally described as Phala-
crocorax atriceps georgianus, a subspecific status
which is probably as close to the truth as
it is possible to come at present, for the
characters by which I once thought to link
it more closely with albiventer (Murphy,
1916, 32) prove not to be valid.
Of the blue-eyed shag inhabiting the
Antarctic Archipelago, and islands of the
Scotia Arc to southward of South Georgia,
I have seen only a few specimens collected
Fic. 71. Heads of three forms of “‘blue- hy Mr. A. G. Bennett and Mr. Lincoln Ells-
eygtsheie fosbow the'lineof demar orth, (Phis somewhat inadequate mater-
cation between dark and light plumage. : : F :
and the characteristic size of the excres- ial, in conjunction with the measurements
cence at the base of the maxilla. Upper, published by Valette (1906, 58), Clarke
Phalacrocorax atriceps atriceps (Chiloé Is- (1913, 247) and Gain (1914, 74), indicate
land); middle, P. a. georgianus (South that the antarctic race is characterized by a
ee te lower, P. albiventer (Caroline * ich longer bill than the South Georgia
sland, Tierra del Fuego). : :
representative and a longer tail than any
other race. It is even possible that the South Orkneys and South Shetlands
may each prove to harbor an endemic race, which would not be surprising
in view of the sedentary behavior of cormorants of this group.
Among all the American blue-eyed shags, males average slightly but con-
sistently larger than females, although the sexes are alike in appearance. The
largest series among our American Museum specimens chance to be made up of
females, and the following table, which includes certain figures taken from
Gain, shows the relative sizes and proportions of several forms. Since Gain’s
measurements of tarsus and foot were evidently taken in a manner differing from
my own, I have omitted these dimensions in the case of the birds from the
Antarctic Archipelago.
THE-BLUE-EY ED*SHAGS 881
; ; Bill from| Depth of Outer toe
Wing Tail | Culmen gape | maxilla Tarsus and claw
P. atriceps atriceps
10 females, continental
South America . . .| 271.4 121.4 57.8 87 8.6 60 100.3 mm.
P. atriceps georgianus
5 females, South Georgia | 275 118.6 48.4 71.6 7.9 59 102
P. atriceps, subspecies
2 females, South Shet-
EWS (0) pits Mena as Aula 302 132 56.2 86.1 65.2 100.3
P. atriceps, subspecies
7 females, Antarctic Ar-
chipelago (Gain) . .| 311 185 56
P. albiventer
12 females, Falkland Is.,
andtheFuegianregion | 276 121 58.1 85.3 8.6 61.1 102.5
In closing these general remarks upon a poorly understood group, I must
hark back to a suspicion hinted at above, namely, that perhaps no more than
two species of blue-eyed shags, divided along latitudinal convergences, and
each with subspecies at numerous islands, may ultimately prove to encircle
the southern oceans and to include all the New Zealand as well as the American
forms.
i MAGELLANIC BLUE-EYED SHAG
Phalacrocorax atriceps atriceps
Phalacrocorax atriceps King, 1828, ZoOl. Journ., 4, p. 102 (Strait of Magellan).
Names: Crested or White-necked Shag or Cormorant; Imperial Shag; ‘‘Lile Imperial,’’ *’ Yeco.
Synonyms of the specific name include imperialis, cirrhatus, elegans, and carunculatus.
Characters: A blue-backed, white-breasted, crested cormorant, with a long white alar bar
over the bones of the mid-wing during the breeding season, a white dorsal patch in post-nuptial
plumage, and brightly colored caruncles at the base of the bill. Among South American examples
the caruncles are of lesser size than in P. albiventer, but adult specimens of atriceps from the Ant-
arctic Zone have large caruncles and represent a distinct race. From a/biventer the typical form of
this species may be distinguished by the course of the demarcation between black and white
plumage on the side of the head (as figured), the ear opening being covered by white feathers.
Adults (sexes alike): Dorsal surface black, with metallic green, blue, and violet sheen; the
luster is dull violet on occiput and neck, green-blue on forehead and crest, dusky blue on back,
rump and flanks, rich dark bottle-green on scapulars and wings; the scapulars, interscapulars, and
lesser coverts have a scaled appearance, each green feather bearing a narrow glossy bluish border;
quills of wing and tail blackish brown, with a greenish tinge when new; shafts of rectrices basally
white; a white alar bar, composed of lesser coverts, extends for from 8 to 12 cm., along the radial
border of the wing during the nesting period; under wing coverts and thighs dusky, with a slight
metallic gloss; entire ventral surface white, the plumage of the throat projecting in a point on to
the gular pouch to a position about under the eye. Iris brown; naked skin around eye blue (vari-
ously described as cobalt, French blue, ultramarine, etc.); nasal caruncles yellow (sometimes gam-
boge or orange), and never developing as conspicuous wattles; bill olive or horny brownish; gular
pouch sooty, with a sprinkling of fine yellow warty spots which give it a yellowish or green-
ish cast; legs and feet pinkish or salmon, brownish on the joints and soles and with blackish claws.
882 OCEANIC BIRDS OF SOUTH AMERICA
3 males (Chiloé Island and Magallanes); wing, 282-287 (284); tail, 117-131 (124); exposed
culmen, 59-64 (61.8); bill from gape, 85-96 (92); depth of maxilla, 9-10 (9.5); tarsus, 64-66 (64.7);
outer toe and claw, 107-109 (108) mm.
10 females (Corral, Mocha Island, and Chiloé Island): wing, 258-282 (271.4); tail, 112-132
(121.4); exposed culmen, 55-60 (57.8); bill from gape, 83-90 (87); depth of maxilla, 8-9.5 (8.6);
tarsus, 57-63 (60); outer toe and claw, 97-103 (100.3) mm.
The crest attains a length of 60 mm. or more.
The juvena] plumage is sufficiently indicated by descriptions of the same stage under one of the
following subspecies, which apparently do not differ. The caruncles of youthful birds are not
tumid, and are mingled with feathers. Nestlings are clad in blackish down, and the naked young
have black wrinkled skin.
The eggs are greenish white and resemble those of related forms. Beck collected none, and I
find no published record of dimensions.
Distribution: Breeding from the southernmost of the Fuegian islets, near Cape Horn, north-
ward along the Pacific coast to Mocha Island, and to Santa Maria Island in the Bay of Arauco
(latitude 37° S.); on the Atlantic coast northward to the Rio Santa Cruz or beyond. Related races
occur at certain islands of the Scotia Arc and in the West Antarctic Archipelago.
Observers agree that the Magellanic Blue-eyed Shag is the most abundant
cormorant throughout the labyrinthine channels of southernmost South
America, from which region its northerly extension is chiefly along the physio-
graphically similar Pacific coast. Reynolds (1935, 80) writes that during
December he found some of the basaltic rocks north of Grévy Island, of the
Wollaston graup, packed with incredible hordes of these birds. He adds that
the species
. was probably breeding on two of the higher pinnacles of rock jutting out of the sea about
the Barnevelt Islands. The only place, however, where nests were definitely investigated was at a
rock in the channel north of Hermite Island. Numbers of a red shrimp were found disgorged about
the nests. The colony was a small one, with only thirty or forty nests, many of which were de-
serted. There were perhaps ten nests with eggs and about a dozen young birds, some almost as
large as the adults and nearly fledged. The smaller chicks were, of course, naked and helpless,
but the elder youngsters left the nests, struggling to climb into other structures higher up by
hooking their bills over the edge and scratching helplessly with their feet. On giving up the
attempt some hid in the rocks, while others simply stood by awaiting developments. The young
are covered with thick black down, including the breast, the ends of the growing rectrices in
some cases abraded brownish, and the basal two-thirds of the bill bluish-grey, especially pale, and
sometimes pinkish, on the lower mandible.
Immature birds in comparatively dull plumage, with the black extending far down on the side
of the face and less white on the neck, were equally plentiful with adults in breeding dress.
The final comment in this quotation is doubtless made with reference to the
opinion of Reynolds that P. atriceps and P. albiventer are doubtfully distinct.
In an earlier paper Reynolds (1934, 349) has reported that many of these
shags nest likewise on a low and stony islet in Lake Yewin, which is north of
Lake Cami in the heart of southern Tierra del Fuego. Here, in early January,
1932, he found adults with and without the white dorsal patch, well-grown
chicks, and nests with eggs, all of which is indicative of the somewhat pro-
longed breeding season of the species.
Mr. Bullock found the Magellanic Blue-eyed Shag nesting abundantly on
the flattish tops of islets and promontories at Mocha Island, Chile, during
November, 1932. Sets of three eggs were just being completed about the middle
MAGELLANIC BLUE-EYED SHAG 883
of the month. The inhabitants of Mocha called the species ‘‘Guanay,’’ a name
applied elsewhere along the west coast of South America to the Peruvian Cor-
morant, which the Mocha folk know as the “‘Cholo.”’ Bullock's observations
comprise the northernmost positive breeding record for atriceps, although he
believes that he also saw birds of this species nesting at Santa Maria Island,
in the Bay of Arauco, during December.
During the Brewster-Sanford Expedition, Beck's collections of specimens of
the Blue-eyed Shag were made at Corral, near Ancid on Chiloé Island, and at
Magallanes in the Strait of Magellan. His observations were, however, far
more extensive, and are worthy of brief summation.
1914
April 23. Common at the mouth of the river near Ancad, mingling with black shags (P.
olivaceus).
July 4. Numbers in the Gulf of Pefias.
November 30 to December 9. Present or plentiful at London, Timbales, Thomas, and Caroline
Islands along the southwestern coast of Tierra del Fuego.
December 17. Hundreds on their nests along ledges of inaccessible cliffs at Black Point, Hoste
Island, with tufts of tussock grass hanging from each nest. The rows of nests were chiefly in
undercuts, where softer rock had eroded away more rapidly than overlying layers of basalt.
December 20 and 24. Fishing in numbers along the coast of Hermite Island, and in Lort Bay,
False Cape Horn.
December 29. Large numbers nesting on the precipices and pinnacles at Cloven Cliff, the
southwestern point of Horn Island.
1915
January 18. Flocks flying in from rookeries on the windward coast to feed in the sheltered
waters around Smoke Island, south of the Brecknock Peninsula.
February 27. Magallanes. Blue-eyed shags fishing for ‘‘sardines,’’ with black-browed alba-
trosses and other ocean fowl, in the Strait of Magellan.
April 7-11. Fledgling shags now common in Lort Bay, False Cape Horn, fishing for ‘‘shrimps"’
all about the schooner at anchor. They are worried by a few young kelp gulls, which seek to
snatch food from their beaks as they emerge. High winds, however, put the gulls to rout, while the
young shags merely float, shaking the water out of their eyes after the chops have broken over
them. If they attempt to rise, they are swept rapidly to leeward.
May 1. Hundreds on the rocks together at Almirante Brown Bay, Gable Island, Beagle Channel.
May 11. Flocks flying from sea at evening toward the estuary of the Rio Santa Cruz, Argentina.
July 23-29. Observed at Navarino Island, near Ushuaia in Beagle Channel, and along all neigh-
boring waterways.
August 2. Thousands off Harberton Harbor, Beagle Channel.
August 4-6. Many fishing in the Strait of Le Maire, and off the Atlantic Fuegian coast to
northward. They swim low in the water, with the tail practically submerged, and leap upward
when diving. The reappearance of a bird is usually in an unexpected or unpredictable place.
In view of the uncertainties regarding the status of Phalacrocorax albiventer in
the Magellanic district, one can hardly be sure that all of the field references
actually apply to arriceps. However, it was in all probability the latter species
which Cunningham (1871, 271) encountered at Santa Magdalena Island, which
lies in the middle of the Strait of Magellan, just south of the Second Narrows,
and not far from Elizabeth or Isabel Island. This author wrote:
\
884 OCEANIC BIRDS.OF SOUTH AMERICA
. Pursuing our way over the island, we ere long reached some large hollows, which
cormorants (Phalacrocorax carunculatus ) had adopted as breeding-places. The birds were there
congregated in their nests literally in thousands, forming a dense black mass covering a space
of many yards; and, on being disturbed, rose into the air in a cloud, winnowing it with their
wings so as to produce a sound resembling that of a strong breeze blowing, and almost concealing
the heavens from view; while a number of skua gulls, associated with them, gave vent to a tumult
of discordant cries. Their nests were regularly shaped flattened mounds, slightly excavated on
the upper surface, and ranged in almost mathematical] series, exactly a foot of space intervening
between each nest. They were formed of dried grass and other herbage baked into a solid mass
with earth and guano; and the generality contained from one to three greenish-white eggs about
the size of that of a domestic fowl, and with a rough chalky surface.
At Quartermaster Island, which lies on the Fuegian side of the Strait, in
the entrance of Jente Grande Bay, Cunningham found a roosting or resting
place of these cormorants, where there were no nests, but where upwards of a
thousand of the birds stood erect, in regular ranks. On the plateau above the
cliffs, the grass had been worn off by their tramplings and the smell of decaying
fish was insupportable.
The South American examples of P. atriceps are not devoid of nasal caruncles,
as has been stated in some of the literature, though these are apparently never
as prominently developed as among the antarctic race or races of the same
species. Neither do they attain the size of the caruncles in P. albiventer. Further-
more, the continental form of atriceps exhibits during the courtship season as
luxuriant a crest as any other race of blue-eyed shag. The usual condition of
the three purely seasonal plumage characteristics of adult birds, allowing for
a certain amount of lag and individual variation, is illustrated by the following
table:
Season Crest Alar bar Dorsal patch
Pre-nuptial maximum absent absent
Egg-laying abraded present incipient
Rearing of young lost maximum | maximum
Moulting begins early during the nesting period, as with most other cor-
morants. The quills are first dropped and replaced, followed by the loss of
the worn body plumage, and the quick growth of the patch of white feathers
on the back. The latter is a short-lived post-nuptial mark. Quite possibly, in a
species which has such a relatively long breeding season, it serves the cormo-
rants as an effective signal that wearers of the patch have passed the point of
being receptive toward amatory advances. The last traces of the patch may
linger until May, or thereabouts.
The most active part of the moult occurs in the late southern summer, that
is, between March and June. By the end of the Jatter month the birds are in
splendid new plumage, with highly iridescent backs, very long crests (reaching
58 millimeters in a female collected at Ancid on June 15), and no trace of either ~
the white patch on the back or the white alar bar. Both the back of the neck
and the white sides of the neck become flecked with decomposed white feathers,
MAGELLANIC BLUE-EYED SHAG 885
some of which may attain a length of 30 millimeters, but which are soon lost.
A similar patch of feathers sometimes appears above and behind the eye. At
the same season (June-July) the gonads begin to enlarge, showing that, in
P. atriceps and related species, the height of plumage should not be called a
‘“breeding’’ garb, but rather a pre-nuptial plumage, at its best during the early
part of the rather lengthy courtship which precedes the nesting season. With
the approach of actual mating, the white alar bar, which is a true breeding
mark, develops. This is demonstrated by September and October birds, which
show considerable traces of wear, and which had already shed or worn off the
longer plumes of their crests. The replacement of the tail quills and remiges is
usually not completed until the end of the breeding season. Some specimens
show the new feathers still growing in April.
Young birds do not put on fully mature plumage, 7. ¢. without trace of brown,
until the second year. It is probable from the appearance of nesting colonies
that they do not breed as yearlings. Nevertheless, a more or less definite trace
of the white dorsal patch appears after the moult of the second summer.
SOUTH GEORGIAN BLUE-EYED SHAG
Phalacrocorax atriceps georgianus
Phalacrocorax atriceps georgianus Lonnberg 1906, Kungl. Svensk. Vetens. Akad. Handl., 40, No. 5, p. 69
(South Georgia).
Characters: Differing from P. a. atriceps of the Magellanic district in its markedly shorter bill,
extremely well-developed caruncles, and in the fact that the demarcation between dark and white
plumage on the side of the head is more ventrad, crossing the ear opening.
Iris hair brown, lightening to gray at its periphery; cornea chocolate; skin surrounding eye
cyanine blue; bare skin of lores and throat blackish brown; caruncles deep chrome; legs and feet
salmon, the under side of toes clove-brown.
I have measured no adult males, which are presumably somewhat larger than females.
5 females: wing, 270-278 (275); tail, 116-122 (118.6); exposed culmen, 44-51 (48.4); bill
from gape, 70-75 (71.6); tarsus, 58-60 (59); outer toe and claw, 100-104 (102) mm.
The maximum length of the crest among the five females is 46 mm. Lonnberg records a length
of 60 mm. ina male.
Newly hatched, naked chicks have livid skin, which turns nearly black within an hour or so,
through oxidation of the pigment. The gular pouch is pinkish, the mandibles slaty blue, the feet
and legs plumbeous. Within five days tufts of fuscous down appear, covering first the back and
neck. Simultaneously the quills of wing and tail sprout as bristly plumules. Finally, tufts of
! white down grow out amid the darker down of the belly, throat, and pileam. The mesoptyle
envelopment is prevailingly fuscous, the face alone remaining bare.
After five weeks, moult of the down exposes the dull greenish feathers of the back. At an age
of seven weeks little down remains except on the neck. A line of pale-edged feathers then indicates
the position of the alar bar; the breast is white save for a few dark flecks; the head and neck are
sprinkled with white filoplumes, especially above and behind the eye; the rectrices have grown to
a length of 12 cm., despite active wear, but the primaries are still short and fresh. The caruncles
are not developed in young birds, but are represented by a brownish, papillate area.
Eggs number either two or three. They are pale dull glaucous blue, with the usual chalky
incrustation. Our only specimens have been broken so that they cannot be measured.
Distribution: South Georgia, and Shag Rocks (2).
At the date of the discovery of South Georgia, in January, 1775, Captain
James Cook wrote, “The shags and soundings were our best pilots.’’ As soon
886 OCEANIC BIRDS OF SOUTH AMERICA
as he had passed off soundings in the fog, he saw no more shags. Elsewhere the
great explorer recorded that these birds rarely go “‘more than half a mile from
their rocks.”’ All of this ts indicative of the sedentary habits of the shags, the
resulting isolation of the colonies, and the evolution of two or more races in
the American quadrant of Antarctica. I myself never saw shags on the whaling
banks off the northeastern coast of South Georgia, where most of the other
resident sea fowl abound.
When a vessel first draws close to the island, however, the shags are likely
to be the first creatures from the land to welcome it (von den Steinen, 1890, 267).
Matthews (1929, 584) notes that they have a habit of flying toward the modern
South Georgian whaling steamers, and then of progressing slowly, close to the
crow’s nest at the masthead. At such times they are knocked down to the deck
by the man on watch and are subsequently served in the whalemen’s mess.
All naturalists who have visited South Georgia since the time of the German
Expedition of 1882 have found that the Blue-eyed Shags breed chiefly in small
colonies of from ten to twenty pairs, building nests on grassy ledges of the sea
cliffs both of the main island and the islets offshore. Often the nests are more or
less screened by drooping tussock, but white blotches of guano below them are
likely to indicate their position. The nests, which are bulky, are constructed
of seaweed, grass, mud, and droppings. The first eggs are laid after the middle
of November, and the period of incubation appears to be in the neighborhood of
five weeks. In the fiords the shags are seen in groups numbering up to about
thirty birds, particularly after the end of the nesting season, when the white
blazoning on their backs—like an athlete’s ‘“‘number’’—makes the adults
conspicuous.
Nothing is known about the taxonomic status of the cormorants which
form a great colony on the Shag Rocks, far to westward of South Georgia, for
the Swedish Antarctic Expedition, which reported its presence, failed to obtain
a specimen (Andersson, 1908, 38).
On my own visit to South Georgia, I saw the first Blue-eyed Shags along
the northerly coast on November 24, 1912. The morning was exceptionally
clear and calm, and most of the cormorants were swimming about among small
bergs and areas of floe-ice. When rising into flight, they kicked heavily along
the surface for considerable distances, seeming to strike with both feet at once.
They flew in string formation, a dozen or more together, and often spread their
broad webs to serve as an adjunct to the tail, especially when stopping head-
way: Their flight seemed to be more or less aimless, for they were inclined to
travel in circles.
In mid-December I found the breeding grounds of the shags on a precipitous
islet lying near the south shore of the Bay of Isles. Here I landed on one of the
first calm days, December 29, and clambered to the top, where the rock was
covered with thick black humus and a luxuriant growth of tussock grass. A
pair of pipits inhabited the small plateau, and also a few burrowing whale-
birds (Pachyptila), to judge by the dismembered skeletons that had been scat-
tered about by skuas; but the principal residents were shags, the nests of which
SOUTH GEORGIAN BLUE-EYED SHAG 887
lined the rocky and grassy ledges all over the northerly or sunny face of the
declivity.
The nests were steep-sided, truncated cones, with a small but deep depression.
In height they measured from 20 to 25 centimeters, the outside diameter at the
rim being about 40. Some were balanced on the tops of dead tussock hummocks;
others rested more stably on the shelves of lichen-covered rock, with long and
dripping icicles overhanging them. The area around each nest was whitened
to a distance of 2 meters by the birds’ ejecta.
Many nests contained sets of two or three eggs, others young birds just
hatched or a few days old, and yet another three practically full-grown fledglings
which had lost nearly all their down. Two or three pairs of adults had appar-
ently not yet laid eggs, and stood upon their empty homes engaged in court-
ship antics.
Both parents were together at most of the nests. I lifted off one female
which had been brooding with her wings spread, and discovered a blind, bare
shaglet, the eggshell from which it had just crawled, and another egg not yet
broken open. It was impossible to keep either parent away from the nest,
although the male was less fearless and persistent than his mate. Both adults
were gentle, not attempting to defend themselves against handling; they merely
watched me sharply with their close-set, blue-rimmed eyes, bringing both to
bear in common focus for a few moments at a time, and then turning the head
to gaze with a single eye. The only note they uttered was a soft croak. They
kept their bills parted, however, the mandible and throat trembling rapidly
in the familiar cormorant reaction. Whenever I tossed a parent aside in order
to see the nestling, it would fly back immediately, and the female would always
settle down upon the nest. The male, less broody, once brought up a billful of
fresh peaty soil, which it worked into the edge of the nest at my very feet.
The ugly chick, which was the center of all this solicitude, behaved as though
it were in a tantrum. It jerked and snapped about the nest bowl, rolling belly
upward, and squeaked loudly all the while.
The courtship or connubial behavior of the shags continued while the nests
were building. Pairs stood side by side, curtseying. The birds would put their
cheeks close together, bow down their heads and necks, then, twisting their
necks, put the other cheeks together in the same way, and curtsey again. After
this graceful minuet had continued for several minutes, the male would launch
off on a short exuberant flight, from which it would return to resume the
love-making.
A few days later I visited the islet again. The shags were still together in
pairs, twisting and curving their necks without cessation. Most of the eggs
had now hatched. It was again evident that females had more pronounced
inhibitions than males against leaving the young in the face of the stimulus of
‘my approach. A territorial response was noted when one pair attacked and
bit the neck of a neighbor which had alighted upon their particular crag.
On January 11, 1913, I made a third visit to the colony. Two young which
had hatched, respectively, on December 29 and a day or two later were now
888 OCEANIC BIRDS OF SOUTH AMERICA
well covered with blackish tufts of down, but they still showed a slight size
difference correlated with age. I found one set of three wholly fresh eggs;
another nest contained two chicks just hatched and an addled egg. The parents
seemed conditioned to stronger broodiness than ever, though in each case it was
the female which tolerated prolonged stroking, while the male retreated to the far
side of his mate, yet still remaining within arm's reach. Undisturbed birds were
bowing, caressing, and circling as usual, besides which they sometimes stretched
up and beat their wings rapidly, without producing any drumming sound.
My last landing at the islet was on February 16, when most of the youngsters
had begun to acquire greenish quills and white breasts, and were wandering
away from their nests among the high hummocks. These chicks had a low,
mellow whistle which they repeated over and over, swelling out their throats.
The breeding ledges had by this time become foul with decayed fish remains
and excreta. The parent birds were rather less confident than when the young
had been helpless, but the females still exhibited far less timidity than the males.
My last view of a shag colony was on the face of a cliff at Possession Bay,
where the adults were still caressing and curtseying as late as March 2.
The only observed food of the South Georgian Blue-eyed Shag was fish of
the genus Notothenia, which the birds obtained by diving among the beds of
kelp. One taken from the throat and mouth of a shag shot at the surface
measured 27 centimeters in length.
Many of the nesting shags proved to be infested with a species of tick
(Ceratixodes putus), the bags of which were about 6 millimeters long. Five such
were taken from the blue feathering on the neck of one incubating female.
ANTARCTIC BLUE-EYED SHAG
Phalacrocorax atriceps, subspecies
Characters: Resembling P. a. atriceps and P. a. georgianus, but with a longer bill than the latter,
larger caruncles than the former, and a longer tail than either. The line of demarcation between
dark and white plumage on the side of the head resembles the condition in the South American,
rather than the South Georgian, birds. Flesh colors of South Shetland adults are described as: iris
pale brown; bill olive to sooty; caruncles yellow; gular pouch sooty, with fine yellowish specks;
eyelids cobalt-blue; feet flesh color, with an olive wash.
2 males, South Shetlands: wing, 312-314; tail, 127.8-138.5; exposed culmen, 56.2-59; bill
from gape, 87.1-89; tarsus, 66.4-68; outer toe and claw, 106 mm.
2 females, South Shetlands: wing, 293-311; tail, 131.5; exposed culmen, 55-57.5; bill from
gape, 82.3-90; tarsus, 64.6-65.8; outer toe and claw, 100.3 mm.
The total length of these four in the flesh ranged between 730 and 826 mm.
Gain's (1914, 74) published measurements of shags from the Antarctic Archipelago are notable
for the tail-lengths. His figures are:
6 males: wing, 305-322 (312.5); tail, 179-208 (191); exposed culmen, 55-61 (58) mm.
7 females: wing, 302-330 (311); tail, 162-208 (185); exposed culmen, 51-62 (56.5) mm.
The total length among these 13 specimens ranged between 725 and 842, and the wing-spread
between 1170 and 1320 mm.
Among South Orkney specimens, Clarke (1913, 247) records a weight of 2948 grams for males,
a maximum bill-length of 63.6, and a maximum crest-length of about 45 mm.
Young stages do not differ materially from those of South Georgian shags.
Eggs from the South Orkneys are described by Clarke as measuring’from 51 to 67 mm. in length
ANTARCTIC BLUE-EYED SHAG 889
by 41 in breadth. Four collected by the French Expedition at Port Lockroy, at the southern end
of De Gerlache Strait, measured 64 x 39, 68.5 x 42.5, 60 x 42, and 64.5 x 42 mm., and weighed
from 57 to 63 grams.
Distribution (one or more subspecies ?): The southerly islands of the Scotia Arc, including
the South Sandwich, South Orkney, and South Shetland groups; and the islands of the Antarctic
Archipelago southward to latitude 65° S., or beyond.
From Mr. A. G. Bennett and Mr. Lincoln Ellsworth the American Museum
has received several examples of Antarctic Shags from the South Shetlands and
neighboring regions. Five from Wilhemina Bay (latitude 64° 30’ S., longitude
62° W.), collected during January, 1922, comprise four adults and a half-grown
downy chick. The male in best plumage had passed its breeding period and has
a white dorsal patch 10 centimeters wide and seven in anteroposterior diameter,
partly concealed by the overlapping wings. The three other adults are moulting,
and show clearly the bleaching effect of the antarctic light. Some of the old
quills of wing and tail have become practically white, the result resembling
that produced by the same agency in the plumage of skuas. The chick is a
counterpart of young birds from South Georgia.
Mr. Bennett has labeled these specimens with a doubtless deserved sub-
specific name, bransfieldensis, which seems, however, never to have been pub-
lished. In view of the systematic work that remains to be done with the shags
from various parts of West Antarctica, I prefer to attempt no further dis-
crimination at present.
At the South Orkneys the members of the ‘Scotia’ expedition found large
numbers of Blue-eyed Shags in 1903, as reported by Clarke and by Brown,
Mossman, and Pirie (1906, 120, 172). Birds were seen throughout the year,
although an autumn emigration took the bulk of them just far enough to
northward or westward to keep them in touch with open water. Whenever
leads opened around the South Orkneys or in the pack-ice to southward, well-
ordered lines and wedges of several score shags could promptly be seen passing
high in air toward the new feeding grounds.
During the summer season the shags avoided the main islands, but nested
by hundreds on rocks and pinnacles off Laurie and Saddle Islands. Clarke
(1913, 246) writes:
On August 2nd a flock containing several thousands, probably early immigrants, was seen
from the Scotia as she lay in her winter-quarters.
The first eggs were obtained on November 8th, on a small islet some forty feet high situated
off the north coast of Laurie Island, where a few Ringed Penguins were also nesting. The nests
were well-built structures composed of seaweed, moss, lichens, and feathers. Some of the birds
were still engaged in nest-building, and were diving and bringing up masses of seaweed in their
bills, while others were busily engaged in picking mosses and lichens off the rocks. They were
great thieves, even worse than the penguins, for when the more timid of the nest-builders retreated
on the approach of the explorers, the bolder birds immediately carried off the momentarily deserted
materials for their own use. A few only of the nests contained eggs, mostly one apiece, though
some had two; and the conclusion was arrived at that the birds had only just commenced laying.
Many of the nests were on rocks, some of them in the sites of previous years; while others were
on pinnacles of ice, having been built on snow which had gradually thawed away all round the
nest, but not at its base. The sitting birds were very confiding, and allowed themselves to be
890 OCEANIC BIRDS OF SOUTH AMERICA
stroked on their nests. On the following day, November 9th, another nesting colony was found
ona small bare islet. Here many of the nests contained three eggs, and the rock between them was
ina terribly unsavoury condition. The usual number of eggs was two, but three were not unfrequent.
Clarke also well describes the seasonal sequence of peculiar nuptial and non-
breeding characters, the crest and nasal caruncles being best developed in
September, a duller aspect and a white dorsal emblem becoming current by
late December or January.
In the Antarctic Archipelago the shags have been studied by numerous
observers, including the naturalists of the Swedish and of two French Expedi-
tions. Important among the accounts are those of Menegaux (1907, 26),
Andersson (1908, 38), and particularly the informing and meticulous record of
Gain (1914, 74).
The distribution of the cormorant throughout this region is very similar to
that of the Gentoo Penguin. It inhabits both coasts of the long peninsuloid
chain of islands and, in common with other organisms, extends farther south-
ward along the westerly or milder shore line. It is never seen far from land, or
from the heavy pack-ice which in winter becomes the ecological and meteoro-
logical equivalent of land. Consequently the migratory movements of the
cormorants have a lesser oscillation than those of penguins, and they have
been observed in flocks during midwinter near such localities as Booth-Wandel
Island (beyond 65° S.), and Snow Hill Island on the Weddell Sea side. Gain
states that lone birds or small groups, which seemed to have the function of
‘‘scouts,’’ were all winter to be seen flying hither and thither, high overhead,
as if in search of new open water.
At their breeding grounds the cormorants are intimates of the Pygoscelis
penguins, the nests often being close together or intermingled. Steep slopes are
the preferred sites of the shags, the crater-like nests, which are built about half a
meter apart, therefore forming series of terraces. Andersson reports communities
of as many as a thousand adult birds on rocks near Trinity and Cockburn Islands.
The reproductive season begins somewhat earlier than in the less severe
environment of South Georgia. The Swedish naturalists observed apparent
mass interest in the old nesting grounds on July 12, when the thermometer
stood at —22° C. In August the shags at Paulet Island became sufficiently
stimulated to snuggle down in their weathered nests, but subsequent cold, dark,
and stormy weather made such behavior prove abortive. Definite courtship is
usually under way about the first of September, and by the middle of the month
the building or rebuilding of the nests commences. Combat is rare, in sharp
contrast with the custom of penguins, and it seems likely that old sites are to
a great extent reappropriated by their former owners, and even that many
individuals retain or reacquire the same mates year after year.
While one member of a pair stands guard, the other hies to ice-free water to
gather reddish algae. Thievery of nest material is universal, and observers agree
that the shags are even more adept kleptomaniacs than their notorious neigh-
bors, the penguins. Bones, feathers, soil when available, and pebbles are mixed
with the seaweed in building.
ANTARCTIC. BLUE-EYED SHAG 891
Menegaux writes that at Booth-Wandel nest-construction ceased about three
o'clock each afternoon, after which the mated couples, which probably abstain
largely or wholly from feeding throughout this period, stood together on their
foundations and engaged in a reciprocal pantomime such as IJ have described for
the South Georgian Shags. The indication of a definite diurnal rhythm in the
patterns of reproductive behavior is highly interesting and merits further study.
Among these shags, by the way, it harmonizes with what is known about their
daily feeding and resting rhythms.
The first eggs appear about the end of October, two or three constituting
the usual set, though more have occasionally been found in one nest. The
chicks conspicuously outgrow the penguins that hatch along with them, so
that by the last days of the calendar year the young shags have an almost adult
look, while many of the penguins are still downy babies. Nevertheless, the
shaglets remain long on their trampled nests, and not until March do they
appear to undertake any fishing for themselves. Thereafter old and young
depart together toward Bransfield Strait, or other bodies of open water, setting
forth about eight o'clock in the morning and returning en masse not later than
four in the afternoon. Rough water may bring them in much earlier, or cause
them to remain at home. When approaching the nesting ground these shags
characteristically swoop toward the ground, which they barely skim until the
final rise, circling, and descent which ends at the nest.
The naturalists of Dr. Charcot’s party banded various young and old shags
at several of the West Antarctic breeding grounds. On November 26, 1909, as
related by Gain, nine of ten adults that had been banded during the same season
of the previous year were discovered again at the Wiencke Island colony, a
most remarkable instance of both homing and survival. Banded yearlings
proved too shy for satisfactory observation, whereas the adults could be handled
at will as soon as the magnetic pull of the nest had taken possession of them.
However, Gain saw indications that broods of the preceding season's young,
which had attained an age of 11 months or more, still showed a tendency to
follow and associate with their own parents after the latter had begun a new
courtship and had long since passed out of the annual “‘mothering”’ cycle.
The principal enemy of the Antarctic Shags 1s the sea-leopard. The skuas
also victimize them, sometimes snatching fish from their beaks the instant
after they have risen to the surface. Fish naturally make up the bulk of the
shags’ food, but euphausians and other crustaceans have been found in their
stomachs, which also often contain pebbles and nematode parasites.
KING SHAG
Phalacrocorax albiventer
Carbo albiventer Lesson, 1831, Traité d'Orn., livr. 8, p. 604 (Falkland Islands).
Names: White-necked Shag; Falkland Blue-eyed Shag. Synonyms of the specific name include
carunculatus, verrucosus, cirrhatus, and purpurascens.
Characters: Similar to Phalacrocorax atriceps, but the purple-black plumage on the side of the
head extends ventrad to a line ona level with the commissure of the bill, besides which no white
892 OCEANIC BIRDS OF SOUTH AMERICA
dorsal patch develops at any time of year. The white alar bar in this species is less extensive than
in atriceps, and the caruncles at the base of the maxilla are more prominently developed than in
the typical or South American race of atriceps. The plumage sequences, including the seasonal
appearance and disappearance of the crest and the alar bar, are similar to those of africeps.
Iris brown (not ‘‘green,"’ as has been sometimes recorded); bill horny brown; ‘'skin round the
eyes campanula-blue; cockles at the base of the upper mandible, saffron mixed with gamboge-
yellow; marks between the eye and the corner of the mouth, orpiment orange’’ (Darwin); feet
flesh color, with brownish webs and soles.
11 males from the Falkland Islands, the coast of Patagonia, and Tierra del Fuego: wing,
273-293 (284); tail, 112-140 (125); exposed culmen, 56-64 (60.4); bill from gape, 83-94 (87.5);
depth of maxilla, 8-9 (8.5); tarsus, 60-64 (61.6); outer toe and claw, 100-109 (104.3) mm.
12 females: wing, 266-285 (276); tail, 99-133 (121); exposed culmen, 54-60 (58.1); bill from
gape, 77-92 (85.3); depth of maxilla, 8.6; tarsus, 58.5-64 (61.1); outer toe and claw, 99-106
(02.5) mm.
Downy young are of an almost uniform clove-brown color, only the head and neck being
slightly darker than the remainder of the body. By the time the contour feathers of wings and
back appear, there is a sprinkling of white filoplumes on the crown and belly. From this stage the
nestlings moult into a plumage which is white speckled with grayish brown on the under surface,
and dull brown, with faint suggestions of green, above. The down clings longest on the neck.
The new feathers of the wings and lower back are edged with grayish white, and they are more
pointed than the corresponding feathers of adult plumage. This, the true juvenal plumage, is
followed by a partial post-juvenal moult, which includes the tail feathers and which clothes the
bird in its first winter plumage, similar to that of the adult, but far less rich. The breast still
retains a few streaks and spots of grayish brown. This new feathering, which is the first winter
plumage, is worn a year. No long crest or large caruncles develop until the second year.
Sets of two and three fresh eggs collected by Beck at Bleaker Island, Falklands, on December 23,
1915, are pale Nile-green, moderately plastered over with a smooth white chalky incrustation.
They are prevailingly very elongate, though several are ovate but with sharp smaller ends. Five
sets measure: 66.8 x 37.8, 64.3 x 38.9; 63.4 x 38.5, 63.6 x 37.4, 65 x 37.2; 61.2 x 41, 62.8 x 38.8,
62 x 40.5; 60.9 x 38.9, 59.3 x 38.8, 59.2 x 39.1; and 62.8 x 38.5, 65.2 x 40, 65.1 x 40.9 mm. These
figures agree well with those of Vallentin (1924, 329) for Falkland eggs, and with those of eggs
from Staten Island ascribed to this species of shag (Hartert and Venturi, 1909, 241).
Distribution: Breeding at the Falkland Islands, and along the Atlantic coast of Patagonia
from Puerto San Julian southward. The breeding status in the Fuegian region is uncertain, but the
species occurs throughout at least the easterly and southerly parts, from the Strait of Magellan to
Cape Horn, and also at Staten Island. It wanders regularly or casually northward along the
Atlantic coast of the continent, reaching the Province of Buenos Aires every winter (Daguerre,
1922, 265). Examples have been taken at the mouth of the Rio Negro (Wetmore, 1926, 412), in
the Gulf of la Plata, and on the coast of Uruguay (Devincenzi, 1929, 6).
As a resident of the Falkland Islands, the King Shag presents no taxonomic
or distributional difficulties other than those concerned with the relationships
among the whole group of circumpolar, blue-eyed cormorants, which is badly
in need of a general revision. The species is the only cormorant of its kind at
the Falklands, where birds which have white cheeks and which develop white
dorsal patches (3. e., atriceps) have apparently never been found.
On the continent and in Tierra del Fuego, the problem becomes complicated,
as pointed out above in the words of Reynolds, because there are apparently
two kinds of blue-eyed shags which, in certain-stages of plumage, can perhaps
not be distinguished. It is even possible that hybridization takes place, but
the question can hardly be solved until more facts come to light.
At any rate, during the Brewster-Sanford Expedition Beck collected abso-
KING SHAG 893
lutely typical examples of Phalacrocorax albiventer in the Strait of Magellan, in
the Beagle Channel, at Caroline, London, and Bertrand Islands, and at Cape
Horn itself, in addition to the series he obtained at Bleaker and Kidney Islands
of the Falklands. Furthermore, the few specimens of fully adult shags that I
have seen from Coy Inlet, Puerto San Julian, and other localities along the
Patagonian coast, are definitely a/biventer and not atriceps. There are likewise
many older records of albiventer from eastern Tierra del Fuego and Staten Island,
such as those of Oustalet (1891, 144) and Salvadori (1900, 627).
Mr. Beck collected two specimens at sea east of Puerto San Julian on Septem-
ber 15, 1915, and recorded others off the Rio Gallegos during the same month.
On September 28, 1914, while working off Mar del Plata, Argentina, he saw
several small flocks pass in the distance. His other notes on the species were all
made at the Falkland Islands.
The height of the King Shag’s pre-nuptial plumage comes with the beginning
of enlargement of the gonads, in July, August, and September, when adults
have swollen and brilliant caruncles, recurved crests composed of 40 or more
plumes and measuring up to 60 millimeters in length, and little if any trace of
the white alar bar. The latter develops rapidly as nesting begins, and at the
same time the crest is reduced through a combination of moulting and dis-
integration of the feathers. Substantial traces of a crest are, however, more
common among birds with young than is true in the case of Phalacrocorax
atriceps. Among some King Shags the total extent of plumage wear during the
breeding season is very marked, while others come through only lightly scathed.
At this period the quills are replaced, and the new primaries do not ordinarily
reach their maximum length until well into the following winter season (July
or August). Young birds in first winter plumage, that is, after the post-juvenal
moult which replaces the abraded and bedraggled tail quills worn in the nest,
often have longer rectrices than they will ever put forth again. The wing in
this species, as among its relatives, is very rounded, the three primaries succeed-
ing the outermost being of subequal length, and the fifth not greatly shorter
than the outermost.
When Mr. Beck approached the Falkland Islands from the Strait of Magellan,
in July, 1914, the first King Shags were encountered about 30 kilometers off-
shore. At later dates he found the birds common in Falkland Sound, and visited
colonies at Cochon and Kidney Islands (November, 1915), East and Bleaker
Islands (December), and West Point Island (January, 1916). The following
notes on the life history of the species are taken in part from Beck's journal and
in part from the published text of Vallentin (1924, 329) and Cobb (1910, 67;
1934, 71).
The shags sometimes nest indiscriminately among Rockhopper Penguins and
Black-browed Albatrosses. Again, they form huge colonies of “‘pure culture,"
on flattish, terraced rock, or on ground once covered with tussock grass. At
the north end of Bleaker Island Beck found such an aggregation of fully a
thousand pairs on December 13, 1915. The dense flocks moving along the water
as they fished offshore reminded him of masses of shearwaters.
894 OCEANIC BIRDS OF SOUTH AMERICA
When the shags are courting, according to Cobb’s sprightly account, the
male will hold the female’s head gently in his large open bill, and the two
will sway from side to side. The birds will then bow, kiss, and nibble each
other about the head, and utter sundry grunts and coos, and a blowing sort
of whistle.
The sound of a large colony during nest-building time in October is respon-
sible for the Falkland simile ‘“‘to make a noise like a shag rookery.’’ At close
range it isa deafening din. The pungent smell, moreover, advertises the location
of the colony a long way to leeward. The time is one of incessant coming and
going of birds with bunches of seaweed in their bills, and in wet weather the
mud, slush, and filth are appalling. Cobb writes that many spotless shirt-
fronts become sadly soiled with splashes from dirty seaweed “‘pinched’’ from
some nest when the owner’s head is turned. Smart tails are dragged through
puddles, like long skirts by careless ladies.
Tussock bog fiber is much used for nest material, and an army of male shags
works at rooting it up with the bills. The males bring it to their mates, which
snatch it and tuck it carefully about them, all the while making a murmuring
o-o-o-o-0. Grass, mud, and algae also enter into the construction of the well-
built homes. Streamers of kelp may be seen festooned around some of the nests,
which are raised high above the ground, so that the brooding shags usually
keep clean despite the Augean surroundings. The small bowls seem ample
enough for the three eggs, but hopelessly outgrown by the time the downy
nestlings begin to expand over their edges.
Why one shag—usually if not always the female—remains at the site during
nest-construction is shown by the alacrity with which an abandoned nest is
pillaged and razed by the surrounding workers. All of this is likely to go on
under the nose of a human observer, for the behavior of nesting King Shags is
almost as nonchalant as that of barnyard fowls.
Egg-laying begins at the Falklands during the last few days of October, but
the height of the season is not reached until late November or December. The
eggs are less heavily incrusted with chalk than those of the Rock Shag CP.
magellanicus). Fanning (1924, reprint, 56) states that they have blood-red
yolks and are too fishy to eat. Incubation begins when the first egg appears,
with the usual result that the chicks are of assorted sizes, being hatched two
or three days apart. They begin to fly, according to Cobb, about three months
after the date of egg-laying.
The exodus of population from a shag rookery is reminiscent of the move-
ments of sheep, for when one shag flies off to sea others are likely to follow by
hundreds within a few moments, streaming low over the water. On the rocks
these shags occasionally stand with their wings spread to the sun and the wind,
in the manner of so many other kinds of cormorants. When sleeping, they some-
times lay the head on the back. They spend much time at their toilet, bathing
in pools of rainwater, scratching their heads with their nails while afloat,
preening and oiling their feathers, making marvelous contortions of their long
necks in the process, and sometimes smoothing off with their large feet. The
KING SHAG 895
nibbling which they give to each other's heads and necks seems also to be a
part of the preening régime (Cobb).
At Bleaker Island, where Beck visited the large King Shag rookery in mid-
December, he found thirty or more Sheath-bills (Chionis alba) hanging about
the margins, now and then making forays among the nests in search of all sorts
of scraps and droppings. The shags paid little attention to such small neighbors
but, on the other hand, they were keenly aware of the dozen or so skuas which
were patiently watching for uncovered eggs. The shags always faced front
toward the skuas, in consequence of which groups of the former presented a
uniform attitude at such a time, and showed as black, white, or piebald,
according to the standpoint from which they were viewed. In the absence of
such a focal stimulus as a skua, the ordinary direction of brooding shags was
that of weathercocks, facing the wind.
During the winter season, Cobb reports, many King Shags are found dead
or dying along Falkland beaches. The same is true of Phalacrocorax magellanicus
in Tierra del Fuego, as related in the biography of that species. It is all sug-
gestive of the pandemic types of disease which periodically affect other sorts of
colonial cormorants, such as the Peruvian Guanay.
Fish of various unidentified sorts, and small crustaceans of both free-swim-
ming and bottom types, have been found in the stomachs of King Shags.
ROCK SHAG
Phalacrocorax magellanicus
Pelecanus magellanicus Gmelin, 1789, Syst. Nat.,.1, pt. 2, p. 576 (Tierra del Fuego and Staten Island).
Names: Magellanic Shag. “‘Nigaud”’ or ‘‘Ninny’’ is the sailors’ name, according to Oustalet
(1891, 151). “‘Lile del Sur’’ appears in some of the Chilean literature. Synonyms of the specific
name include sarmientonus, erythrops, leucotis, mentalis, penicillatus, ater, and perhaps ewmegethes.
Characters: This species has the weakest bill, with the smallest dertrum, of all South American
cormorants. Head, neck, and dorsal surface greenish black in breeding plumage, but chin, throat,
and fore neck white during the winter. A small but conspicuous auricular tuft of white feathers.
The wing is exceptionally rounded.
Adults (sexes alike): Head and neck black, with steel-blue gloss, which becomes purple with
wear, and with a scattering of white filoplumes; a pre-nuptial crest upon the head, of which the
longest feathers are lighter and more brilliant, verging toward green, and attaining a length of
about 50 mm.; a conspicuous patch of white feathers on the ear coverts; interscapular region and
wings bottle-green, each feather narrowly margined with a darker hue; lower back, rump, upper
and under tail coverts, flanks, and thighs black, with more or less steel-blue gloss, all of these
parts interspersed with long white filamentous feathers and tufts; remainder of ventral surface,
including the chest, white; quills of wing and tail brownish black, with a slight gloss on the outer
webs, all of them, particularly the rectrices, fading and fraying greatly with wear. Iris red (at
least while the adults are breeding); bill blackish; gular pouch and lores brick-red, flecked with
yellow scale-like excrescences, which give the face an orange cast; legs and feet flesh color, the toes
darker.
In post-nuptial plumage the throat becomes white, and the crest and white fleckings are lost.
The sequences are discussed further in the text.
10 males from the Magellanic region (Caroline, London, Navarino, and Bertrand Islands;
Beagle Channel; Chiloé Island): wing, 245-258 (252.6); tail, 128-155 (141); exposed culmen,
48.5-54.5 (52.6); bill from gape, 68.5-79; tarsus, 52.5-54 (53.5); outer toe and claw, 88-95
(91.4) mm.
896 OCEANIC BIRDS OF SOUTH AMERICA
20 females: wing, 237-255 (244); tail, 123-146 (134.4); exposed culmen, 48-55 (52); bill from
gape, 70-78; tarsus, 49-53 (51.2); outer toe and claw, 85-91 (88.2) mm.
5 males from the Falklands: wing, 233-263 (251.4); tail, 127-142 (134); exposed culmen,
51.5-54 (53); bill from gape, 72-76; tarsus, 51.5-54 (52); outer toe and claw, 89-95 (91) mm.
9 females: wing, 236-255 (246.4); tail, 129-134 (130); exposed culmen, 46-51.5 (49); bill from
gape, 69-73; tarsus, 49-53 (51); outer toe and claw, 86-89 (87.4) mm.
Young birds have the iris brown; subsequent changes may be due not entirely to age but also
to the incipience of the breeding period, or to other causes, for very full notes on the labels of
specimens collected by Beck indicate that there is the following sequence or variation in the color
of the iris among birds from any one locality: brown, dull orange, yellowish, whitish, white,
ink, red.
The legs and feet of young birds are blackish, changing to flesh color, with dark toes, as they
mature. The transformation is very gradual, and in the examination of specimens it can apparently
be used as a criterion of age. The plumage sequences of the young have apparently never been
described and are reserved for the text below.
The eggs number from 2 to 5, 3 being perhaps commonest. The form varies between cylindrical
ovate and elongate-ovate, and the color of the shell is a faint greenish or bluish white, with the
usual chalky and blistered surface. At East Island of the Falklands Beck collected one set of 2,
two of 3, and one of 5, on December 10, 1915. The average measurements of these 13 eggs are
62.4 x 37.9 mm. The longest and widest eggs, respectively, measure 69.1 x 37.8 and 59.5 x 39.8
and the two smallest, 55.8 x 37.2 and 65.2 x 36.5 mm.
Distribution: Falkland Islands and the southerly coasts of South America, from the Rio Santa
Cruz, Argentina, to the vicinity of Corral, Chile. According to Hellmayr (1932, 300) the breeding
range on the west coast is on islands from Llanquihue southward. The species has been casually
recorded from near Talcaguano (Paessler, 1914, 272), and at least once from Valparaiso (Schalow,
1898, 681).
The Rock Shag is a relatively sluggish and sedentary cormorant which
inhabits the winding coast lines and hidden channels of southern South America.
It is particularly common throughout the Strait of Magellan and connecting
waterways, southward quite to islands behind Cape Horn. The structure of
its wing seems to be correlated with its habits and habitat, for this organ is
much more rounded than that of cormorants which brave the winds of the open
ocean around the antarctic islands or along the coast of Peru. In the wing of
the Rock Shag, the second, third, and fourth primaries from the outermost are
sub-equal in length, while the fifth is nearly or quite as long as the first. It
would be rash to say that such physical equipment makes the bird particularly
likely to be beaten down and exhausted by the gales of its tempestuous home-
land. Nevertheless, in connection with numerous observations in the record,
it is suggestive of weak flying powers. Crawshay (1907, 150) speaks of the
particular frequency with which he found carcasses of this shag along the
beaches of Useless Bay, Tierra del Fuego, without being able to assign any
reason as to why such examples had come to grief. Furthermore, Cobb (1934,
57) states that birds of this species always fly very low over the water, and that
even when taking flight from a cliff they swoop down close to the surface
before getting up speed, a custom which is responsible for the Falkland saying
that the Rock Shag cannot fly until it has wetted its tail. Reynolds (1934, 349)
also states that the flight is never high, and that the birds neither sail nor soar,
but rather beat along steadily with the head stretched straight forward and
held a little lower than the neck.
ROCK SHAG 897
During Mr. Beck's travels on the Brewster-Sanford Expedition he collected
his first examples of the Rock Shag as far north as Corral, and thereafter found
the species common all the way from Chiloé to Cape Horn. Among his speci-
mens are birds from Caroline, London, Navarino, and Bertrand Islands, various
parts of Beagle Channel, and the Falkland Islands. He also obtained evidence
that the Rock Shags nest throughout these regions, although he collected eggs
only in the Falklands. In the latter colony the eggs of this species, like those
of the King Shag, are regularly gathered for eating, though Cobb (1910, 67)
says that both sorts are inclined to be decidedly ‘‘tasty.'" The Rock Shags
themselves have also long furnished a source of food to the indigenous Magel-
lanic Indians, and I fancy that this is the species indicated in the following
quotation from Byron (1748, 140), which refers to a locality not far north of
the western entrance of the Strait of Magellan:
A night or two after they sent out some of their young men, who procured us a quantity of
a very delicate kind of birds, called shags and cormorants, Their manner of taking these birds
resembles something a sport called bat-fowling. They find out their haunts among the rocks and
cliffs in the night, when taking with them torches made of the bark of the birch tree, which is
common here, and grows to a very large size (this bark has a very unctuous quality, and emits a
bright and clear light; and in the northern parts of America is used frequently instead of a candle)
they bring the boat's side as near as possible to the rocks, under the roosting-places of these birds;
then waving their lights backwards and forwards, the birds are dazzled and confounded so as to
fall into the canoe, where they are instantly knocked on the head with a short stick the Indians
take with them for that purpose.
In the neighborhood of the Gulf of Ancad, the northern limit of the breeding
range of this species on the Pacific coast, the shags collect in flocks before the
nesting season, which lasts from November until April or later. They choose
for sites the tops of straight-sided blocks of rock on the islets, and build their
homes of a variety of seaweeds, laying from two to four, or sometimes five,
eggs (Germain, 1863, 315; Hellmayr, 1932, 300). In this region Beck saw many
nests with large young during April, 1914. Half a year later, he found the
Rock Shags nesting on the ledges of cliffs along the leeward sides of London-
derry and Caroline Islands, off Tierra del Fuego. In addition, a number were
occupying a cave on a small islet close to Caroline Island. Some of the nests
were here placed fully 50 meters back from the entrance, so that only the white
breasts of the birds were visible through the dim light. Such a choice of nesting
site is reminiscent of the habits of the Red-footed Cormorant (Phalacrocorax
gaimardt) in grottoes of the Peruvian coast. Reynolds (1935, 73) states that one
of the species of tussock bird (Cinclodes) shows a strong predilection for the
vicinity of Rock Shag colonies.
Elsewhere in Tierra del Fuego, as well as at the Falklands, the Rock Shags
are reported as nesting in similar situations, sometimes on the fronts of deep
gulches below which the sea boils. Only rarely do they seem to take to flat
open spaces, such as are favored by the King Shag (Phalacrocorax albiventer).
Rookeries are numerous along the shores of West Falkland, and Beck saw many
also on East Island and at the small islets of Bleaker, Sea Lion, and others.
In places where long, straight, perpendicular cliffs have been cut by wave
898 OCEANIC BIRDS OF SOUTH AMERICA
action, the shag nests are sometimes arranged with great regularity along the
ledges for considerable distances. Many are apparently used year after year,
being refurbished during the month of October. They are tricked our, in fact,
very gayly and picturesquely, bits of bright color being supplied by green or
red.seaweed, intermingled with tussock grass, stones, and leaves and twigs of
diddle-dee or other shrubs. Sometimes mud is also used, and the entire mass
soon becomes thoroughly plastered by the droppings of the birds. The first
eggs at the Falklands are laid in November, the season agreeing substantially
with that in other parts of the range. Beck collected a number of sets on
December 10, 1915.
As soon as the nesting season is under way, pairs of skuas invariably attach
themselves to a shag colony in order to profit by opportunities to steal eggs and
newly hatched chicks. The skuas seem to fly in regular beats up and down the
rows of incubating cormorants, although, when they come too close, the
sitters thrust out their necks and protest ineffectually. Despite the fact that
the parent shags change places quickly at relief periods, the skuas always
succeed in a certain amount of decimation. Nor does the maltreatment of the
eggs end here, for they are not infrequently broken by the hurried departure
from the nest of the shags themselves. This damage appears to be due to the
pumping action of the feet as the birds spring off. The feet strike downward
together with the same movement when the shags leave the surface of the
water. The shells of the eggs are relatively thin and weak, as among all cor-
morants; Abbott (1861, 167) has suggested that their limy excrescences and
nodules may serve somewhat to strengthen them.
The Rock Shags are, of course, hatched without feathers, wearing only
what looks like a black rubber suit. Their subsequent stages of down and
plumage have never been fully described, and the sequence presents certain
peculiarities which warrant an account based upon 25 males of all ages in the
Brewster-Sanford Collection.
The first down is clove-brown, which soon becomes mixed on the belly with
white down. The relative amounts of white and brown down vary individually,
but the white is always confined to the belly alone, except for a few sprinklings
on the head and neck. The moult of the down exposes the juvenal or first con-
tour plumage, which is brown tinged with dull bottle-green on the back, and
white on breast and belly. This white juvenal belly feathering has not pre-
viously been described. It is mixed with a few partly brownish feathers, but is
nevertheless sharply white from the brown neck and upper breast to the base
of the tail. Birds in this plumage from Ancid, Chiloé, were taken in April;
juvenals in the same plumage from the Falkland Islands are dated January,
doubtless indicating earlier hatchings.
With the growth of the young shags, the white belly feathers are replaced
by brown feathers, so that when the birds are nine to ten months old they are
entirely dark. The brown belly is, however, composed of white feathers which
are brown only at their tips, and by a process of wear and growth the belly
becomes white for the second time, a condition which is thereafter retained
ROCK SHAG 899
throughout life. The seasons of the successive steps in these plumage changes
vary in different parts of the range of the bird, as might be expected. Among
the Magellanic Shags of Nassau Bay, near Cape Horn, the date of breeding is
doubtless more definitely fixed by climatic conditions than it is at the Falkland
Islands or in Central Chile.
Simultaneously with the appearance of the permanent white breast of
juvenals, the white throat also develops, but the latter is not acquired by wear,
like the breast, but entirely by moult and a growth of new white feathers.
Sometimes, however, the white throat does not develop until after the first
nuptial plumage has appeared.
At the end of a year, or thereabouts, a complete moult of both quills and
body feathers leads to the first nuptial plumage. At this time the colors have
their maximum richness. A crest is developed, the white ear-patches appear,
the head, neck, and flanks become glossed with steel-blue, and the back with
oil-green, while the breast is immaculate. The nesting season is scarcely under
way, however, as is shown both by breeding specimens and by Mr. Beck's
photographs from life, before white feathers again appear on the throat, sub-
sequently spreading to the sides and base of the neck, and sometimes even on
to the crown. The crest, moreover, is soon dropped, and the bird has assumed
its so-called winter plumage. It should be borne in mind, however, that the
latter plumage is characteristic of many birds that are still nesting. Nuptial,
post-nuptial, pre-nuptial, etc., would be more accurate designations for the
stages of adult birds.
A series of Falkland Island females likewise shows well the continuous
changes from nuptial to post-nuptial plumages. While the birds are nesting,
in November, the ear-patch rapidly enlarges, white feathers appear in the throat
and cross over the head, and in some specimens the remains of the crest itself
become white because of the growth of a band of white across the forehead.
According to Cobb, the Rock Shags start on their fishing expeditions soon
after the coming of daylight, when they can be seen setting out by the hundreds.
They feed chiefly in kelp fields close to the coast, diving for fish among the
submarine tangles of this seaweed. Usually they leap almost out of water
before plunging beneath the surface, where they make use of their wings as
well as their feet while foraging about. The various sorts of small fish that
they catch must be brought to the surface before they can swallow them, which
sometimes results in the prey being filched literally out of their mouths by the
ever-watchful skua.
GUANAY
Phalacrocorax bougainvillii
Carbo bougainvillii Lesson, 1837, Voy. ‘Thétis’ et de ‘]'Espérance,’ 2, p. 331 (Valparaiso, Chile).
Names: Peruvian Cormorant. Local Spanish names in one part or another of the west coast of
South America include “‘Pato Yeco,”’ ‘‘Lile,"’ and “‘Cholo.’’ The only common synonym of the
specific name is albigula.
Characters: A long-billed, long-winged, bicolored, crested cormorant, with a white throat-
patch and green circumorbital] skin.
900 OCEANIC BIRDS OF SOUTH AMERICA
Adults (sexes alike): Top of head and crest dark oil-green; remainder of head and neck black,
glossed with steel-blue; interscapular region, lower back, rump, upper tail coverts, and thighs
glossed with dark bluish green; sides of upper back, wing coverts, and scapulars dull bronze-green,
each feather with a narrow margin of darker greenish blue; a median white elongate patch on the
fore neck extends from the anterior pointed feather-tip on the pouch caudad for 7 cm. or there-
abouts; ventral surface white from the base of the fore neck to the under tail coverts, which are
dark; a slight patch of white filoplumes above the eye, with others scattered here and there on the
neck; quills of wing and tail greenish black, the rectrices tending to fade rapidly with wear.
Iris dark brown, surrounded by a clear white ring of cornea, which is more or less visible posteriorly
in life; surrounding bare skin olive-green, succeeded beneath by a crescent of dull brown skin
which loops slightly around the cephalad and caudad extremities of the green area; outside this,
in turn, the bare skin of the face is red, somewhat orange above the eye and somewhat brownish
behind it; bill horny or brownish black, with scaly accretions like those of pelicans, and with
faint pinkish and bluish tones at the base of the mandible; gular sac brownish; legs and feet flesh
color, sometimes almost pink, the toes and the back of the tarsus brownish.
5 males from Lobos de Tierra Island and Ancén, Peru, Tofo and Corral, Chile: wing, 281-303
(296.4); tail, 96-104 (100); exposed culmen, 65-78 (71.4); bill from gape, 91-107 (99.2); tarsus,
66-71 (68.8); outer toe and claw, 91.2-105 (98) mm.
4 females from Peru: wing, 270-287 (281); tail, 96.6-108.5 (103.3); exposed culmen, 65-73
(69.1); bill from gape, 86-99 (93); tarsus, 66-67 (66.6); outer toe and claw, 90-97 (93.4) mm.
Young birds moult from the down into a plumage resembling that of adults, but more brownish
and less richly colored throughout. They very closely resemble certain stages of the young in
P. magellanicus, which is doubtless a near relative. The down is an even mixture of black and
white, producing a pepper-and-salt effect peculiar to this species.
The eggs closely resemble those of P. atriceps and P. albiventer, being of the usual, somewhat
elongate cormorant shape. A set of three collected at Pescadores Island, Peru, December 13,
1919, shows heavy but patchy limy coating, large areas of finely granular, Nile-blue shell being
exposed. The specimens measure 64 x 40.7, 65.7 x 41.6, and (broken) x 40 mm.
Distribution: Breeds on islands along the west coast of South America from Lobos de Tierra,
Peru, southward to Mocha Island, Chile; ranges from Point Parifias southward to Corral, and
casually farther to northward and southward.
The Guanay, first in importance among the famous guano birds of Peru, has
been called the most valuable bird in the world. Coker (1919, 484), after a
conservative calculation regarding the quantity of guano normally deposited
on an islet by a cormorant of this species, continues,
Fowl] which produce $1.43 worth of guano a pair annually, without expense for care and
feeding except the minimal cost of protection, may well be appraised at $15.00 a pair. The fowl
which dwelt on the South Chincha Island alone, when it was visited in 1907, might well be re-
garded as an asset representing a value of several millions of dollars.
The Guanay is a relative of the pan-antarctic “‘blue-eyed’’ shags. The ring
of bare skin surrounding its eye is green rather than blue, but in its general
structure and plumage-pattern, its carunculated bill and nuptial crest, it re-
sembles not only the Rock Shag (Phalacrocorax magellanicus) but also the more
southerly species, atriceps. The cross-section of the long, deeply incised bill,
the feathering of the gular pouch, and the number of tail quills are further sug-
gestive of relationship with the southern circumpolar shags. Like the Peruvian
Penguin and Diving Petrel, and so many other endemic creatures of the Hum-
boldt Current, the Guanay is descended from ancestors which long ago invaded
this peculiar littoral region from the south.
GUANAY 901
In the course of its evolution the Guanay has, however, undergone a number
of remarkable specializations. It is a long-winged cormorant, capable of flying
strongly for hours against the brisk southerly breezes that blow every afternoon
throughout the greater part of its range. No other cormorant in the world,
perhaps, is so distinctly aérial. Furthermore, it feeds exclusively upon surface
organisms, rather than upon animals of the sea-floor or of the kelp fields, and
its method of flock-fishing involves the discovery of its prey from the air, rather
than by means of a submerged search. It is likely that only one other kind of
cormorant, namely, Phalacrocorax capensis of the west coast of South Africa,
has developed similar ways as regards flock-fishing upon an extensive scale.
The Cape Cormorant, at any rate, is described as flying out to sea from African
bays in formations numbering a hundred thousand birds (Spiess, 1928, 223).
This species and the Guanay are not closely related, but they inhabit homolo-
gous cool-current regions, and both illustrate the interaction between organ-
ism and environment which has resulted in the evolution of a common habitus.
Together with the Piquero, the Peruvian Pelican, and several other voracious
surface-feeders of the Humboldt Current, the Guanay is in effect a machine for
converting fish into guano. A relatively small proportion of this is deposited
upon the islets, where it becomes available for human use; the remainder returns
to the sea where, however, it is not ‘‘lost,’’ for it restores to the water the
fertilizer of the marine pasturage and thus finds its place in the closed circuit
that runs from chemicals through various stages of life, and back again to
chemicals. Single colonies of Guanays dwelling on Peruvian islands take out
of the surrounding ocean waters more than a thousand tons of fish a day
(Murphy, 1925, 81). Man's utilization of the resources of the ocean along this
coast is, indeed, as nothing compared with that of the birds. Schweigger, as
quoted by Schott (1935, 395), has computed that, whereas the people of Peru
capture and market annually about 4000 metric tons of fish, the sea birds of
the country devour 5,500,000 tons!
Thus, presumably, since the uplift of the Andes and the beginning of the
meteorological and hydrological conditions as they exist today, has the process
been going on. We know little about the age of the Guanay as a species but,
as I have already noted, it has been described under at least one other name as
a fossil or subfossil cormorant from northern Chile (Philippi, 1895, 14). Fur-
thermore, it seems to be the sea fowl, erroneously listed as a penguin (“‘ Apteno-
dytes’’), from the bottom of a 30-meter layer of guano at Huanillos, Chile
(Ribera, 1904, 339). Lambrecht (1933, 239) estimates that if the substance had
here accumulated at the moderate rate of 5 centimeters a year, not allowing
for surface wastage, the mummy had been buried for at least eight to nine
thousand years.
Coker has pointed out the ease with which a Guanay population may be
counted at the breeding ground, because of the even distribution of the nests
and the complete coverage of all practicable terrain. The birds turn around and
squabble with their neighbors as they prepare the breeding sites for the recep-
tion of eggs, for which reason the distance from the center of one nest to the
902 OCEANIC BIRDS OF SOUTH AMERICA
center of adjacent nests is exactly the “‘sparring space,’’ or about 60 centimeters.
Coker found 39 nests in 12 measured square meters of ground, and 52 nests in
another 18 square meters; 3 per square meter is a fair average. The census of
adults is therefore 6 per square meter; that of adults and young not less than 12,
for the Guanay lays 3 eggs and rears an average of more than 2 young. The
nesting territory covers all relatively smooth level or gently sloping ground,
and the borders of a colony, no less than the interior, are usually densely popu-
lated and sharply defined. The nests begin as mere scrapes lined with feathers
Cmostly tail quills), but they soon become small craters in a continuous carpet
of guano, each having an outside diameter of about 40 centimeters, of which
the bowl comprises half. More than a million such nests, occupied by between
four and five million birds, have been counted or measured on the central
Chincha Island.
Since the bulk of my personal observations concerning the Guanay are quoted
below from an earlier publication, I wish to write in further detail of only two
matters, namely, the normal range of the species, and the periodical wanderings
which are generally, if not always, related to the rhythmic Nifio phenomena or
similar aberrations of climate and hydrography.
The most populous breeding colonies of recent times have been characteristic
of islands between central and northern Peru, or from Independencia Bay to
Lobos de Tierra. Shifts in the centers of abundance may be due in part to the
temporary disturbances of guano exploitation, but they are also in large measure
unpredictable. However, it would be a rare year in which most of the following
islets or groups were not occupied by impressive colonies of Guanays: Santa
Rosa, Ballestas, Chinchas, Asia, Pachacamac, Pescadores, Mazorca, North
Guafiape, and Macabi. Lobos de Tierra is also often the home of large numbers,
though in relatively small aggregations. The high islands, such as Vieja, San
Gallan, Fronton, and San Lorenzo, are avoided. The most distant breeding
station from the mainland coast is at Hormigas de Afuera, where a few Guanays
were on their nests at the date of the visit of the yacht ‘Zaca,’ in February, 1935.
In southern Peru and in Chile there have been few reports of densely occupied
communities within recent decades. The islet of Alacran, off Arica, is occasion-
ally ‘‘black with Guanays,’’ and no doubt the birds have bred there now and
again from time immemorial. Many islets to southward along the coast prob-
ably harbor small colonies, for.in December, 1932, Mr. D. S. Bullock found
these cormorants abundant all around Mocha Island, and nesting by hundreds
on a small outlier known as Isla Muerta. He preserved one skin, and the head
of another adult, and reports that on December 8 the inhabitants of Mocha
visited the colony of the ‘‘Cholos’’ and gathered hundreds of eggs for food.
This is the southernmost breeding record of the Guanay, so far as known.
Delano (1817, 315) and Morrell (1832, 105) both refer to the southern head-
land of Santa Maria Island, in the Bay of Arauco, as headquarters of an enor-
mous colony of shags, which put forth to sea in order to fish at a distance from
the island, and darkened the sky when they returned. ‘‘One hundred barrels
of their eggs . . . may be collected in a very short time,’’ writes Morrell.
GUANAY 903
Despite the well-known gift for exaggeration possessed by the latter captain,
the testimony of Delano is reliable, and both descriptions fit no other cormorant
than the Guanay. Delano’s observations were made in the year 1800, when
the ground of the colony was white with the ordure of the cormorants. Might
it be possible that the shags recently seen by Mr. Bullock at this same island
were Phalacrocorax bougainvillit and not, as he thought, P. atriceps?
In Part I, I have made several references to the disasters which overtake the
Guanays, and other sea fowl of the Humboldt Current, at times when the warm
countercurrent from the north causes a cessation of upwelling along the coast
of Peru. The effects are in proportion to the strength of the cause. They are,
therefore, most marked at intervals of about seven years, and are particularly
pronounced during seasons of extraordinary disturbance, such as those of 1891
and 1925. Various reasons, such as starvation due to the death of food fishes,
avian tuberculosis, aspergillosis (a fungous disease), and an abnormal multi-
plication of endoparasites have been assigned as the intermediary agency which
destroys the birds. Doubtless each has its part, and all are covered in Peru by
the general term ‘“‘peste,’’ meaning a pandemic malady. In any event, its source
lies in change of the physical environment and a resultant malnutrition. The
whole cycle is doubtless to be correlated with the periods of excessive increase,
climactic competition, mass emigration, and destruction, which have been
studied with relation to many species of organisms, both of the land and of
the sea.
In the case of the Guanays, the birds in an affected area of the littoral ocean
first become ‘‘loco’’ or queer. The flocks move in unusual directions, and beyond
the limits of the normal range. Many birds die and drift ashore, and the sur-
vivors behave in an unwonted manner, of which two or three instances are given
below. For example, on March 4, 1925, after the Nifio Current had been in
full swing for several weeks, an immature Guanay came aboard my launch not
far south of Tumbez, Peru, sat on a coiled hawser while it preened its feathers,
and subsequently allowed itself to be played with and passed from hand to
hand. It seemed to enjoy being stroked and tickled and, while perching upon
my knee, it even bit my fingers tenderly, just as a puppy bites in fun!
During the same memorable season, I observed small flocks of doomed
Guanays out of their normal districts, as in various parts of the Gulf of
Guayaquil and even far up the Rio Guayas. At the same period, the birds were
dying by hundreds of thousands in the unduly warm water along the greater
part of the Peruvian coast.
In 1932, the phenomena were in part repeated, as recorded heretofore in
the words of Sheppard (1933, 210). Mr. A. Hyatt Verill (én litteris) states that
after the strong countercurrent and heavy rains of that southern-hemisphere
summer, Guanays again invaded the Guayas, and died in droves at Guayaquil.
Others, however, penetrated the Ecuadorian rivers still farther toward the
interior, while at sea they wandered along the tropical coast at least as far as
the latitude of Buenaventura, Colombia. It is unlikely that any such cormorants
survived to find their way back to the guano islands.
904 OCEANIC BIRDS OF SOUTH AMERICA
Less familiar, but of peculiar interest, is the fact that strange emigrations of
ill or ‘‘unbalanced’’ Guanays take place from the southerly limits of the specific
range, as well as in the north. This subject has been discussed by Moore (1926,
176), who writes of a mass emigration from the Peruvian coast into central and
southern Chilean waters, after the disastrous summer of 1925. At Coquimbo,
even before the beginning of the rains at the northern end of the Humboldt
Current, the Guanays came ashore in hordes, apparently seeking food among
the cattle, or in the troughs of swine! Large numbers were killed with sticks
by the inhabitants. At San Antonio, at least 20,000 were observed dead or
dying, and others pushed on southward into Magellanic waters. A single
specimen examined proved to have the liver heavily infested with roundworms.
Millions of hungry Guanays, concludes Moore, ranged along the coast of north-
ern Chile, seeking food, and at least a few of them apparently survived to return
northward.
Below is my own record of the life history of the Guanay as I was able to
work it out in the course of all-too-rapid travel, and amid the press of many
other duties, during the Peruvian spring and summer of 1919-1920. In this
account the plural form of the word is spelled in the Spanish manner—Guanayes.
Picture to yourself the shining, rainless coast of Peru, washed by ocean waters to which storms
are unknown, where the swells surge northward, from month to month and year to year, before
winds that blow regularly from a southerly quarter. On such an ocean dark flocks of guanayes
form rafts which can be spied miles away. Slowly the dense masses of birds press along the sea,
gobbling up fish in their path, the hinder margins of the rafts continually rising into the air and
pouring over the van in some such manner as the great flocks of passenger pigeons are said to have
once rolled through open North American forests in which oak or beech mast lay thick upon the
leafy floor.
At other times, when the guanayes are moving toward distant feeding grounds, they travel
not in broad flocks but rather as a solid river of birds, which streams in a sharply marked, unbroken
column, close above the waves, until an amazed observer is actually wearied as a single formation
takes four or five hours to pass a given point.
Equally impressive are the homeward flights of these cormorants, after a day of gorging upon
anchovies, when in late afternoon slender ribbons, wedges, and whiplashes of guanayes in single
file twist and flutter, high in air, toward the rounded plateaus of white islands which gradually
turn black as the packed areas of birds swell out from clustered nuclei toward the borders of the
available standing room.
Given . . . abelt of cool ocean waters replete with small organisms . . . , together with
nesting sites upon islands which for climatic reasons could never become encumbered with vegeta-
tion, and the geographic stage was set for the northward emigration of the ancestors of the guanay.
Furthermore, because of the normal superabundance of food, conditions seem to have been pre-
arranged for the increase of the birds to numbers limited only by competition with other animals
and by the amount of safe, insular space for reproduction. Although suitable islets are very
numerous, the enormous food supply in the Humboldt Current is still out of all proportion to the
area of the breeding places. This doubtless explains the excessively colonial nesting habit of the
guanay, in which it surpasses all other birds, even the penguins, for in the middle of a bounteous
sea there would be a constant tendency for the cormorant population to become more and more
congested upon the islets. The doctrine of Malthus applies to birds as well as to men.
These facts suggest that the geographic background does not tell the whole story. Evolution
is, at least in part, the result of interaction between a living being and its surroundings. The guanay
itself has had to undergo considerable modification in order to fit into a new environment, especially
as regards the particular character of its food in the Humboldt Current. Several such adaptive
GUANAY 905
changes are apparent, changes which have progressed so far that they now strongly differentiate
the Peruvian species from its antarctic cousins and from every other kind of cormorant in the world.
For instance, the guanay, unlike any other cormorant, ‘‘hawks’’ its food, that is, it hunts
exclusively by sight and from the air, locating the fishes which it seeks before descending to the
water to catch them. Most cormorants search for their prey individually, swimming alone or in
loose groups at the surface, then plunging in what seem to be favorable places and conducting the
hunt as well as the capture while they are submerged. For the most part, moreover, they subsist
upon bottom-living species of fish, often diving down many fathoms in pursuit of single victims.
But the guanay feeds altogether upon surface-swimming fishes, such as anchovies, young herrings,
and the toothsome silversides which the Peruvians call pejerreyes (‘kingfish’’). Such forms travel
in tremendous schools which are assailed en masse by proportionately large flocks of birds.
The correlation between the numbers of the fishes and the extreme gregariousness of the cor-
morants results among the latter in a system of efficient codperation which almost suggests certain
customs of ants or other social insects. The vast flocks of guanayes which spend their nights upon
the islands do not start hunting in a body when morning breaks. On the contrary, the birds first
sally forth only in small scouting parties, which can be seen flying erratically above the ocean,
usually keeping well in air, and frequently ‘back pedaling’’ or hovering when they see the silvery
glint of schooling fish or the ruffled appearance of the sea which indicates the presence of fish
below. The dropping of the scouts to the surface, and the shallow dives which mark the beginning
of an orgy, are the signals that cause the approach of such rivers of birds as have been described
above. The cohort of guanayes then spreads out as a great fan over the unfortunate anchovies,
which are likely to be no less harried from beneath by bonitos and sea-lions. Small wonder that
the Peruvian fishermen, who are familiar with such sights, believe that the guanayes and the seals
have a working understanding! However this may be, the gorging proceeds until both sea-lions
and birds must cease long enough to allow their rapid digestions to fit them for another meal.
From the crop and gullet of a dead guanay the remains of no less than seventy-six anchovies, four
to five inches in length, have been taken.
Sometimes the guanayes pursue the fishes to the very beaches, so that a rare view of a one-
sided fray may be enjoyed by a landsman. One morning during my sojourn at Independencia Bay
shoals of silversides were packed in deep, glittering ranks close to the quiet shore, when a raft of
guanayes, accompanied by a few pelicans and a horde of screaming gulls, drove the fishes before
them against the shelving sand. Soon the water gleamed like flashing quicksilver, and in wild
rioting the birds jammed and crowded each other until hundreds of them were pushed clear beyond
the tideline by the scrambling mob behind.
The guanay stands and walks erect, somewhat after the manner of a penguin. Its height is in
the neighborhood of twenty inches and the weight of a full-grown bird about four and a half
pounds. It has a glossy green and blue-black neck and back, a white throat-patch which is a con-
spicuous mark in flight, a white under surface, and pinkish feet. During the courtship season a
crest of plumes develops at the back of the head. The guanay’s iris is brown, but an area of green,
naked skin surrounding the orbit makes it look at close range like a veritable personification of
envy. A second ring of turgid red skin, outside the staring “green eye,’’ heightens its extraordinary
expression. . . .
The breeding season, like that of many tropical ocean birds, is practically continuous, but it
reaches a climax during the southern summer months of December and January. In its adaptation
to an all-the-year nesting habit, the species has, of course, diverged widely from the ways of its
antarctic relatives, the reproductive season of the latter being rigidly fixed by the climatic cycle.
Individual pairs of guanayes are believed commonly to rear two broods during a single year. The
flight of the last families of the young of one season, in May or June, is at any rate followed hard by
the courting and love-making of adults in preparation for the breeding season of the second spring.
In early October, 1919, when I arrived at the Chincha Islands, the resident guanayes were in
the early stages of mating. From this place and date, as investigations were carried northward
from island to island, successive manifestations of the birds’ life history were revealed, until at
Lobos de Tierra in January, 1920, full-fledged young were observed taking to the ocean, quite
independent of parental care.
906 OCEANIC BIRDS OF SOUTH AMERICA
At South Chincha Island in mid-October the breeding grounds were covered with just one
year’s accumulation of sun-baked guano, and the cormorants were getting ready to nest again.
They stood in compact bodies, each comprising thousands of birds, on the flat top of the island,
and, when a human being approached, all those on the nearer side began to stir—not en bloc, nor
yet individually but in groups of a few hundred, each of which for the time constituted a unit.
One group would move rapidly away, the birds carrying themselves bolt upright. Another group
would advance toward the observer, so that this section of the army would gleam with white
breasts instead of shiny, dark backs. Still another unit would rush to the right or to the left, so
that both the dark backs and the white breasts showed at once, and the long bills and red nasal
warts became conspicuous. Such closely huddled companies soon collided with others moving in
different directions, producing much confusion about the margins. A few of the birds showed no
fear at all, stolidly permitting a man to approach within a few feet. The greater proportion,
however, frantically took to flight, rushing helter-skelter down a slope, and raising a cloud of
dust with their whistling wings. The air became bewilderingly thick with birds as they circled
overhead, but within a few moments the number returning to earth once more exceeded the
number taking wing.
When an observer makes his way slowly and very quietly into the heart of a colony in which
nesting has definitely begun, the guanayes gradually retreat, and one may sit down in a clear circle
which is at first fifty or more feet in diameter. But almost imperceptibly the birds will edge in
again, until the bare circle narrows to but three or four paces. From such a point of view it seems
as though the ground were covered with as many pairs of sprawling webbed feet as there is room
for, and yet new arrivals plump down by scores or hundreds every minute. Over the ocean, more-
over, to the north, south, east, and west, one may commonly see endless black files still pouring
in toward the island. The hum of wings is like the effect of an overdose of quinine upon the ears,
and the combined voices seem like mutterings of the twelve tribes of Israel. It reminds one of all
sorts of strange, oppressive roarings, such as the noise of railroad trains in river tunnels. The
near-by voices, which can be distinguished individually, are merely sonorous bass grunts and
screepy calls. It is the multiplication of such sounds by numbers almost too large to imagine that
makes the outlandish and never-to-be-forgotten babel.
Toward evening of such October days, most of the guanayes would be courting, after strenuous
hours at sea during which all their energies had doubtless been devoted to winning the sustenance
of life. Privacy does not enter into their notion of fitness, and while six or seven birds occupy
each square yard of ground, the love-making antics are often in full progress. These are in general
not unlike the courtship habits of the closely related antarctic cormorants. Two guanayes stand
side by side, or breast to breast, and ludicrously wave their heads back and forth or gently caress
each other's necks. The crests upon their crowns are frequently erected, and the feathers of the
nape puff out so that the velvety necks appear twice their normal thickness. Cheeks and chin-
pouches continually tremble, and chattering bills are held wide open. Now and again one will
bend its body forward and at the same time extend the head upside down along the spine and toward
the tail, holding this curious, paralyzed attitude for several seconds. Sometimes the birds of a
pair snap so much at one another that it is hard to judge whether they are making love or quarreling.
Indubitable quarrels between birds of different pairs also go on without cessation, and occa-
sionally many join together in a mélée. Every now and then, for example, some unfortunate
guanay, which seems to be the butt of all bystanders, will go dashing through the throng, holding
its head as high as possible in order to avoid the jabs and bites which all others direct at it. If
the victim would but stop fleeing, perhaps the blows would cease, but it keeps more and more
desperately running the gantlet, flapping its wings, bumping into innumerable neighbors, until
eventually it bursts from the vicious crowd into a clear space, shakes itself with an abused air,
and opens and shuts its mouth many times with an expression of having just swallowed an
unpleasant dose.
In the early stages of courtship it often happens that several cocks select the same female for
their addresses. In one instance, five assiduous suitors, all with necks expanded, were observed
bowing around a single hen which crouched in their midst. But by no means all the birds are
engaged in love-making at every moment, for they spend much time preening their feathers,
GUANAY 907
frequently raising the coverts of the tail and thrusting the bill toward the oil-gland. Then, after
combing their heads and necks thoroughly with their claws—a real feat in balancing—they prome-
nade in small troupes along the outer edge of the colony.
Visible actions, rather than unusual sounds, alarm the courting birds. A quick motion of the
hand will start sudden pandemonium. Even when an observer rises to leave them as slowly,
silently, and unostentatiously as possible, a small panic inevitably results, many of the nearer
birds beginning to scamper about or to take flight. On the other hand, the firing of a gun straight
into the air produces scarcely a stir provided the weapon is not brandished. The effect of human
conversation is, however, most amusing. Whenever a man, sitting perfectly still, begins to talk
to the guanayes in a loud voice, a silence falls over all the audience within hearing. Their mumbles
and grunts die away, and they listen for awhile as if in amazement.
During the course of a few hours’ resting on any island, the birds get much befouled with
fresh guano, which hardens upon their plumage. They periodically rid themselves of this by
flying some distance off the lee side of the island where they plunge and violently beat the water
with their wings. Sometimes most of the inhabitants of a colony will make their toilet in this
way at one time, producing a thunderous roar which can be heard from afar. It is often audible
during morning fogs, when the flocks are invisible, and as a boat draws near such a gathering it is
easy to mistake the sound for the dreaded crashing of waves upon unseen rocky shores.
Inhabitants of the Peruvian coast are agreed that the guanayes never spend the night upon the
ocean, as the native pelicans often do, but that they return to their island roosting places even
when the journey involves a flight which must continue long after dark. I have sometimes watched
from two o'clock in the afternoon until nightfall, or for about five hours, while they streamed
uninterruptedly homeward. A few piqueros often accompany them, as if filling honorary positions
in the line, but fully 999 in every 1000 birds are guanayes.
The grandest sight of the day, when the homeward flight is at its maximum, usually comes
during the hour before sunset. From some point far away the birds make a beeline for the center
of their island, but, as they near their destination, they invariably skirt the shores so as to come
down across the wind. The instinct of following a leader is evidently strong; if, for any reason, a
file is broken, and the rear birds turn toward the left coast instead of the right, those behind will
obey the signal and all swing into the new course. Close over gulches and ridges of their home
island the oncoming streams of birds flow, the separate ‘‘rivulets’’ cutting across each other like
the blades of scissors. At the same time these files also rise and fall in beautiful undulations which
can best be seen from the crest of a hill above them. Sometimes three or more such lines will flow
along for a while 10 to 15 yards apart, but sooner or later one of them will make leeway until two
files interweave. Then the soft, humming swish of wings is interjected with sharp clicks as the
quills of two guanayes strike together in air. When one beholds the endless mingling, the crossing
and recrossing and tangling of the lines, it seems incredible that more birds do not clash.
It goes without saying that such gregarious creatures as the guanayes must have natural
enemies to prey upon their abundance. The sea-lions of the coast have been accused of devouring
the fledglings when they first take to water, but, so far as my observations go, there is little evi-
dence to support the charge. The naked, black-skinned, and very ugly chicks, which hatched
from rather small greenish eggs, are apt to be thickly infested with feather-eating lice (Mallophaga)
transferred from the plumage of their parents, and yet, so long as the sensitive nestlings are shielded
from the hot sun, they seem to suffer no ill effects from these parasites. Other birds, in fact, appear
to be their only serious enemies.
When I landed upon Asia Island, off central Peru, on December 4, 1919, great destruction of
guanay eggs had been wrought by gulls, turkey vultures, and condors. Although a colony con-
taining countless eggs and young still covered about half of the western slope, extending from the
summit almost to the water, and filling a deep ravine as well as the rounded hillside, the other
half had become a waste of empty nests and broken egg-shells, and had been deserted for the season
by the parent birds. Early in the morning of this day, guanays were leaving their breeding ground
to pour out over the Pacific in an unbroken column which was following a school of fish in a tre-
mendous sigmoid curve toward the north. The colony was, however, still densely peopled with
homekeepers, 7. e., the birds of each pair which had remained to cover the eggs or the newly
908 OCEANIC BIRDS OF SOUTH AMERICA
hatched, squeaking chicks. The nests were luxuriantly feathered with molted quills, which, by
the way, the brooding birds were forever stealing from each other's foundations. Many walked
about carrying bunches of feathers, or flew elsewhere with a bill full. In the heart of the colony
stood a condor, with a small circle of abandoned and rifled nests roundabout. When this pilferer
had been shot and picked up by the feet, the albumen and mostly unbroken yolks of a round dozen
of fresh eggs slid out of its gullet. Scarcely any pieces of shell were visible in this rich meal, the
supposition being that the condors must suck the contents of the eggs through their trough-
shaped tongues.
Later in the month of December, the guanayes were observed in more advanced stages of the
nesting period at the Pescadores and Huaura Islands, to the northward of Callao. Here their
robber-enemies were less in evidence, perhaps because the government guardians had been using
their guns freely, and few empty nests or broken eggs were noted. Although a certain proportion of
the adults were incubating new sets, the latter probably represented second broods, for the nests
were exceedingly large, and the quills which had once formed a lining were now buried deeply
‘under the craters of guano which constituted the rim of each nest chamber. Moreover, nearly
full-grown young, in pepper-and-salt plumage, were abundant everywhere. These chicks were
inclined to be indiscreet in wandering away from their own headquarters, whereupon they would
presently be chastised by old birds and would have to scurry ignominiously back to their respective
home sites. Among the larger chicks the approved method of obtaining food was to shiver and
plead before their elders until the latter acted as though they were frantic from the teasing. As
long, indeed, as the adults were at the nests, the youngsters never let up trying to ram their heads
down the parental throats, and it was nothing unusual to see two or even three dive together into
a capacious and well-stocked crop. At this season the sound coming from a colony bore some
resemblance to an April frog-chorus, for the high-pitched voices of the chicks tended to drown
out the mumbling of the old birds.
Still older fledglings had gone down in droves to the quiet rock pools around the shores, where
they flapped their wings and dived until they had become proficient in the ways of maturity. Late
every afternoon thousands of these apprentices could be seen scrambling up the steep hillsides
from their training grounds, striving to get back with the crowd before dark. Such was their
strange indifference to the presence of man, that they made no protest when we picked them up
by their pinions and helped them on their way. This lack of fear is not necessarily innate. It
may be due rather to the familiarity of the birds with guardians who never harm them, an idea
suggested during a later visit to an isolated colony of guanayes on the large island of Lobos de
Tierra, where both old and young were unwontedly timid, and where all the chicks that were
big enough to walk left their nests pell-mell at the approach of a human being.
At Mazorca Island, of the Huaura group, a splendid colony of guanayes occupied practically
all of the southern or windward slope, from the very brink of low precipices, over which the
spray flew, to the crest of the island. Breeding gannets mingled to a certain extent with the
cormorants along the lower border of the nesting ground. A few birds of both kinds had estab-
lished themselves also on the northern slope, out of the wind, but here their enemies had been
active and had succeeded in devouring many eggs. It seems to be characteristic of the vultures and
gulls to attack at the edges rather than in the midst of a colony, and thus tend to annihilate pro-
jecting portions and small outlying groups. Perhaps this is one of the evolutionary factors which
have caused the guanayes to breed in such compact hordes.
The birds at Mazorca were most tenacious in clinging to their nests, even when a man stepped
over them. In late afternoon many of the broods were covered by both parents, which were so
huddled together that they looked like single birds with two heads. One usually had a wing,
for instance, over the back of its mate. When approached, they bristled all over until their plumage
resembled that of Japanese bronze eagles. They would then wave their heads threateningly, and
hiss with widely opened bills.
In the forenoon the colony usually appeared thin and gray when viewed from the lofty balcony
of the lighthouse; but by three o'clock in the afternoon it would be black, owing to the return of
tens of thousands of additional birds. Before alighting, most of the homecomers soared back and
forth considerably in the fresh breeze. Whenever one came to earth in the wrong place, it would
GUANAY 909
immediately disclose its mistake by what can only be called a “‘lost’’ expression. Other guanayes
in the vicinity would grasp the situation at once, and would then assault the newcomer, forcing
it to take wing again at much sacrifice of dignity. It was a genuine misfortune for birds to alight
where they were not welcome, for they seldom got off without being thoroughly pecked and
jabbed. Such extraordinary reactions answer the question, so often asked, as to whether colonial
birds always find their individual homes among myriads of seemingly identical nest-hollows
distributed over acres of undifferentiated surface. Above all else, Nature jealously. guards the
unity of the family; each mated pair must fulfil its own obligation of rearing offspring to maturity,
and every unconscious tendency to depart from this responsibility is nipped in the bud (Murphy,
1925, 74).
BIGUA CORMORANT
Phalacrocorax olivaceus olivaceus
Pelecanus olivaceus Humboldt, 1805, in Humboldt and Bonpland, Rec. d'Observ. Zodl. et d'Anat. Comp.,
p. 6 (Magdalena River, latitude 8° 55’ N., Colombia).
Names: ‘‘Cuervo de mar,’ meaning sea-crow, is perhaps the commonest name in most parts of
Hispanic South America, but ‘‘Bigiia"’ or ‘“Mbigii4,”’ in imitation of the grunt of the bird, and
probably of Indian origin, is also widely used; in northernmost Peru, this cormorant is called both
“Patillo’’ and ‘‘Guanay Negro,”’ but farther southward these two nouns are reserved for other
species of the genus; ’Yeku,’’ according to Bullock's notes, is the Araucanian name, from which
we have “‘Pato Yeco,’’ which has spread up and down the west coast of South America; Beck also
records in his notes ‘Pato del Diablo,"’ the latter being a sort of equivalent of the North American
hell-diver, as applied to grebes; reported also are ‘Pato Cuervo"’ and ‘‘Pato Pescador’’; Die-dapper
is the name among English-speaking inhabitants of the Corn Islands; ‘‘Corta"’ is a native name in
Venezuela, and ‘‘Pareka,’’ an Indian one in Guiana; ‘‘Corvo Marinho"’ is used in Brazil, as the
equivalent of the Spanish “‘Cuervo de Mar,"’ and sometimes this cormorant is listed there as
Mergulhao, a term ordinarily applied to boobies. Azara’s work on Paraguayan birds refers to
this species as ‘‘Zaramagullén Negro,"’ a noun which is usually reserved for grebes. The commonest
specific name in the literature is vigua, because Humboldt’s prior name olivaceous was disinterred
only as recently as 1926; other synonyms include brasilianus, brasiliensis, niger, gracilis, ventralis,
and probably promaucanus and eumegethes.
Characters: The only South American cormorant in which the adult is clad in a wholly dark
plumage, resembling the majority of cormorants of the northern hemisphere.
Adults in breeding plumage (sexes alike): Head, neck, lower back, rump, upper tail coverts,
and ventral surface glossy black, the feathers at the base of the neck being somewhat elongate and
fluffy and forming a crest or mane; naked skin of throat and gape outlined almost from eye to eye
by a narrow white band of feathers; a tuft of long white filoplumes in post-auricular position and
others, mostly of smaller size, showing over the greater part of the neck, as well as in the lores
and above and behind the eye; plumage of the upper back, wing coverts, and scapulars lanceolate,
of a color close to dark olive-gray, each feather with a black shaft and bordered with blackish;
primaries and rectrices glossy black, tending to fade rapidly with wear. Iris green (called ‘‘lustrous
myrtle green’’ by Lane, but sometimes recorded as blue); bill bluish horn-color, usually rugose and
in some instances covered toward the base with overlapping horny “'shingles’’; gular sac and bare
parts of face yellow or yellowish; legs and feet black.
28 males from Panama, Venezuela, Colombia, Peru, Bolivia, Argentina, and Chile: wing,
271-305 (283.3); tail, 144-181 (166.6); exposed culmen, 54-61 (57); bill from gape, 79-90; tarsus,
51-59 (55.1); outer toe and claw, 82-93 (87.3) mm.
18 females: wing, 250-282 (270); tail, 139-175 (154); exposed culmen, 49-58 (54); bill from
gape, 75-88; tarsus, 50-57 (53.6); outer toe and claw, 76.5-90 (84.3) mm.
A series from the mouth of the Amazon and elsewhere, measured in the Berlin Museum, show
dimensions agreeing with the above. Five adults taken at the Chincha Islands, Peru, October 27,
1919, had an average weight of 1680 grams.
The immature plumage is dull brownish, with only slight suggestions of gloss. In juvenal
stage the breast is more or less white. The down of nestlings is blackish.
910 OCEANIC BIRDS OF SOUTH AMERICA
Eggs number usually three or four, though full sets of from two to six have been recorded.
No specimens appear to exist in the American Museum Collection. Oates (1902, 203) records
measurements of eggs from Chile as ranging from 52.3 to 62.5 mm. in length, and from 36.3 to
39.4 in breadth.
Distribution: Coasts, rivers, lakes, and marshy regions of Central and South America, from
Nicaragua to southern Argentina and Chile, and from sea level to high Andean lakes such as
Lago Junin, Peru (altitude 3932 meters). A distinct race is found in southern Tierra de] Fuego,
the geographic boundaries between the two forms being still undetermined.
The “‘Bigiia’’ or “Cuervo de Mar,”’ which has been mentioned so often in
my account of a hypothetical circumnavigation of South America, is found in
every country on the continent, ignoring altitude no less than latitude. Not
only does it occur along the seacoasts, but also up the courses of almost every
river to its headwaters. It breeds on arid islands that lie in front of desert
shores, among the trees of steaming tropical swamps and lagoons, on cold
beaches soaked by the nearly perpetual rains of the west-wind zone, and on
the banks of lofty mountain lakes such as Titicaca and Junin. In short, it ex-
hibits a diversity of habitat and a climatic toleration which are perhaps with-
out parallel.
In Central America the range of the typical subspecies gives way to that of
a more northerly race (mexicanus), which extends into the United States. In
the extreme southern tip of South America is a third race, to be described here-
after, which is found close to Cape Horn, the northern limit of its distribution
remaining to be determined.
A large series of this cormorant was collected by Beck and myself, besides
which specimens from many other sources give the American Museum a repre-
sentation of the species from practically every section of South America. From
Panama to the Rio Gallegos in southern Patagonia, a single race seems to hold
sway. The measurements of about forty specimens show considerable variation
which is, however, quite within the range of normal individual differences,
and which exhibits no consistent association with geographic source. Thus,
two specimens from Lake Titicaca have unusually short bills, whereas others
from the not distant Lake Junin have bills of average length for the series.
A number of birds from the coast of central Peru have definitely longer tarsi
than most others, but the difference is at best slight and inconstant. Neither
does geographic variation, as it has been pointed out in the literature, seem to
hold. It is stated in the ‘‘Catalogue of Birds of the British Museum”’ that ex-
amples from the southerly parts of South America have shorter tails than those
from tropical regions. I find, on the contrary, that the longest rectrices among
all the birds I have studied belong to a specimen from the south of Chile. It is
further stated in the ‘‘Catalogue’’ that this cormorant has but twelve tail quills,
but no less than four specimens, among the thirty I have examined with refer-
ence to this character, have fourteen rectrices, and a number of others show
thirteen. Wetmore (1926, 412), too, records a female from the Rio Negro with
thirteen rectrices. From all such data, I conclude that Phalacrocorax olivaceus
olivaceus is a highly variable race in all parts of its range. It is not unlikely that
more exhaustive work may yet show further geographic correlations. Certainly
BIGUA CORMORANT 911
the members of the species inhabiting southern Tierra del Fuego and the ad-
jacent islets seem to represent a well-marked short-billed subspecies, which is
to be considered in the next biography.
In the style of its throat-feathering, the Bigiia differs from all the other South
- American cormorants, for the line at which plumage and naked skin meet usually
runs squarely across the base of the gular pouch. Occasionally one finds a
specimen in which there is a slight point at the mid-line; this is especially true
among immature birds, indicating perhaps an ancestral condition in which the
feathering once projected forward, as it still does to a much greater extent in
Phalacrocorax gaimardi and in all of the white-breasted cormorants of supposed
sub-antarctic origin. The type of throat-feathering in the Bigiia is, indeed,
doubtless one of a number of signs showing its affinity with the dark-colored,
northern-hemisphere members of the family. The bird bears a close resemblance
in general morphology, color, the feathering of the face, and the rugose charac-
ter of the bill integument, to the holarctic group of cormorants, and it is pre-
sumably of northern derivation. In fact, the chief pronounced difference between
olivaceus and the North American species auritus is that the former has lanceolate
instead of broad plumes on its back and scapulars, as well as a border of white
nuptial feathers extending from eye to eve behind the gular sac.
The height of feathering in the Bigiia, when the head and neck become
decorated with long white rudimentary or obsolescent plumes, apparently does
not coincide with the actual nesting season. It appears, rather, to be a court-
ship plumage which reaches perfection somewhat before nesting time. It is
probable that in certain tropical districts, such as the coast of northern Peru,
this cormorant has no fixed breeding season, which may account for the mixture
of plumage stages and physiological conditions to be noted among examples of
such origin. In short, the potential variability of this cormorant with reference
to seasonal rhythm may be no less marked than that concerned with altitude,
latitude, and climate. Among tropical examples, moulting birds are represented
practically throughout the year. In the succession of the quills, the middle
rectrices and the inner remiges are replaced first. In full-plumaged condition,
the second and third from the outermost primaries are the longest, and are
sub-equal. The lateral rectrices of certain specimens show distinct traces of the
diagonal crinkling or crossbarring, which is usually or always characteristic
of the Snake-bird (Anhinga). A noteworthy feature of the plumage of this
cormorant is also the ‘‘mane”’ of long soft feathers situated on the back, just
at the base of the neck.
Since the Bigiia is found in all parts of South America, it has been the subject
of a relatively enormous literature, of which neither space nor time will here
permit more than a few important references to coastal distribution. The species
is common in the western Caribbean Sea, although specimens obtained by
Peters (1929, 134) at Corn Island show signs of intergradation between the
races olivaceus and mexicanus. It is found in vast numbers near Ciénaga, in the
Santa Marta district of Colombia, and also along the courses of the great
streams to westward (Todd and Carriker, 1922, 132). The cormorants are abun-
912 OCEANIC BIRDS OF SOUTH AMERICA
dant on most or all the islands off the coast of Venezuela and, according to
Clark (1902, 258), they do not as a rule mingle with the other species of sea
birds offshore. Beebe (1909, 78) reports a flock in one of the mouths of the
Orinoco, a short distance above the Gulf of Paria. The bird abounds in boggy
districts along the Corentyne coast of British Guiana, where the sea often
floods the shore and where there are miniature islands covered with marsh
plants. Here the cormorants may be seen resting on oozy mounds, with wings
half-open, in the attitude which is so characteristic of a number of northern-
hemisphere cormorants (Young, 1929, 3). Schomburgk reports that in Guiana
the species is still more commonly found on the rivers, especially near water-
falls (Chubb, 1916, 198).
In the Berlin Museum I have examined specimens taken at Marajo, at the
mouth of the Amazon. Friedmann (1927, 147) observed examples in the harbor
of Rio de Janeiro, and in marshes about the border of the city, as well as from
here down the coast to the roadsteads of Montevideo and Buenos Aires, and to
adjacent inland regions. Subfossil bones of this species are known from the
great limestone caverns near Lagoa Santa, in the province of Minas Geraes,
Brazil (Winge, 1888, 5 and 11). At Carrasco in Uruguay, Beck saw many on
February 14, 1916, and Aplin (1894, 197) has seen a thousand or more feeding
together in early morning off Uruguayan beaches. Wetmore (1926, 53) has
found the birds common in channels traversing the marshes and tidal flats of
eastern Argentina. Gibson (1919, 517) also states that they are abundant in
the Cape San Antonio district wherever there is water, either salt or fresh, and
that on the coast they are distinctly birds of mud flats rather than of sandy
strands. They are always present in the muddy crabberies or “‘cangrejales’’ of
this low coast. Salvadori (1900, 627) and Crawshay (1907, 149) report them
from the central and southern Patagonian seashore. Off the mouth of the Rio
Chubit large flocks remain at sea throughout the day, and fly up the river to
fish in fresh water at night.
The distribution of the species in Tierra del Fuego will be discussed in the
next biography. Typical examples of the present race are, however, well
represented from the central and southern provinces of Chile, where the “‘Pato
Yeco’’ is everywhere familiar. Lane (1897, 186) says, in fact, that it is the most
numerous of all Chilean coastal sea fowl, increasing toward the south and pene-
trating streams as far as the base of the Andes. The birds are usually seen
singly along these rivers, flying up and allowing themselves to drift down with
the current while fishing. Hellmayr (1932, 298) attributes to Albert the asser-
tion that the Bigiia breeds on lagoons of the Cordillera, up to an elevation of
2000 meters or more, which does not seem improbable in view of its habits in
the northern Andes. Beck’s journal states that he saw it nearly everywhere
among the islets of southern Chile during the Brewster-Sanford Expedition.
On a bar of the river at Anctd, Chiloé, he often noted flocks of fifty or more, at
the time of his visit in April, 1914. Bullock observed a few pairs at Mocha
Island. Lane found the birds on the coast of Arauco, where they were accus-
tomed to fly up the rivers to roost in the trees of the forest some 15 kilometers
BIGUA CORMORANT 913
inland. Beck observed as many as 200 massed together in the harbor of Corral,
and in the Berlin Museum I have examined specimens collected by Plate during
the month of October on the Isla de Pajaros, off Coquimbo. Reed (1896, 206)
and Paessler (1909, 102) report the species as common along the arid coast of
northern Chile. From here northward, throughout the length of the Peruvian
coast, it has been observed by every member of American Museum expeditions
in the region. I encountered it everywhere during my own Peruvian field work,
perhaps in greatest or most concentrated numbers among the protected straits
and channels along the islet-dotted eastern side of Asia Island. Von Tschudi
(1844, 314) persistently recorded this species from the coast of Peru under the
name Plotus anhinga. His misidentification has led in turn to endless repetition
of error. Asa matter of fact, the Snake-bird does not occur anywhere along the
desert stretch of western South America.
In Ecuador I found the Cuervo in many localities, particularly in the Gulf of
Guayaquil, where, on the evening of February 24, 1925, there were many thou-
sands on a bar off the southern tip of Puna Island. A few were noted at El
Muerto Island, as well. Flights of the birds at morning and evening in the Gulf
indicated that they were going to and returning from more or less definite
feeding grounds every day. Between this vicinity and Panama the Cuervo
appears to be everywhere present, nesting in numbers at the Pearl Islands,
and being common about the Pacific entrance of the Panama Canal (Hallinan,
1924, 307).
Apparently this species does not willingly go out of sight of shore, but hugs
the coast closely, not venturing to islands that lie more than a few kilometers
out atsea. This is highly significant in view of the fact that it never has reached
such islands as the Galapagos, Juan Fernandez, or even the Falklands. On the
other hand, it is understandable why it frequents many of the Caribbean and
West India Islands, as well as others which are either close to the continent or
are members of a continuous chain.
On piers, lighters, and all kinds of wreckage along the coast of Peru, the
Cuervos perch and grunt. Passengers landing from steamers often look over
the edges of the piers in search of the droves of pigs which they assume must
be confined somewhere below their feet. It was in such a situation that I first
saw a large aggregation of these cormorants at Pisco, on November 8, 1919.
When I looked over the railing of the long dock, I could see the projecting tails
of hundreds of birds that had come there to roost. They were spaced evenly in
tiers, like fowls on the perches of a chicken-house. Many of the brownish
younger birds were mingled with the glossy adults. Even as one looked through
the chinks between the planks under foot, the upturned green eyes, and the
white hackles on the heads, were conspicuous. Other cormorants were still
coming in to join the roosting throng, and, as they approached the pier, they
would set their wings and soar, a style of flight more characteristic of them
than of most species of cormorants. Just before swooping upward to alight,
they would invariably stretch down the naked skin of their throats in a way
that reminded me of the dew-lapped lizards (Tropidurus) that one sees every-
914 OCEANIC BIRDS OF SOUTH AMERICA
where on the bare rocks of the Peruvian coast. The ability of a seemingly
clumsy web-footed bird, such as this cormorant, to perch upon the slender steel
rods which serve as struts of a pier, is astonishing. They are, however, even
capable of sleeping all night on the wire topmast stay of a ship, which stretches
from point to point at an angle of forty-five degrees.
In this part of its range along the Pacific coast, the Cuervo seems to have
become almost a domesticated bird. At wild and remote islands, such as San
Gallan and Vieja, where there are no fishermen’s shacks or other structures
built by man, it is relatively rare. But on all the smaller guano islets which
have docks and buildings, and in every port where there are ships, small craft,
buoys, water-pipes, wrecks, or aérial trolleys with cordage, it is invariably
abundant. Toward evening of every day during the last two months of 1919,
the sunken hulk of the square-rigger ‘Leonidas,’ off the coast of North Chincha
Island, was usually well covered with Cuervos, from the highest spars to the
bulwarks. I counted seventy-six of the birds roosting on this vessel at sunset
of November 23.
Along the beach of Talara, in northern Peru, I have seen Cuervos working
at the very edge of the water, engaged in catching small fish thrown against
the shore by the waves, and paying little attention to Indian boys swimming
near or even among them. In the same manner I have seen them feeding in the
company of Indian fishermen at the mouth of the Rio Chira. In January, 1920,
I found them plentiful at the Lobos Islands, mingling on rocky sections of coast
with the Blue-footed Boobies, and on sandy beaches with the Kelp Gulls.
Sometimes on the higher points they were close even to Turkey Vultures, which
they resembled curiously when both species stood with their wings half open,
their backs to the sun. At Lobos de Afuera, on January 5, I found the nests of
the cormorants on little pinnacles of a gulch, more or less surrounded by incu-
bating Peruvian Boobies (Sula variegata). The cormorant nests were composed
of seaweed, and were balanced upon the tops of small blocks of rock 20 to 30
meters above the water. Families of fledgling young, numbering two or three,
continued to return to these platforms to rest even after they had taken flight
and had begun to undertake more or less fishing for themselves.
At Estorbo Islet, off Puerto Deseado, Patagonia, Doello-Jurado (1917, 11)
found the nests of Cuervos on the tops of low stiff shrubs of a species of Arriplex.
Here the nests were constructed of twigs. In February they contained young in
various stages of growth, only one unhatched egg being observed. The adult
cormorants ejected fishes when they were approached. Along the coast of
Chiloé Island, according to Germain (1860, 315), these cormorants nest either
on rocks or in trees bordering lakes. Their bulky nests are often made of aquatic
plants and give off the offensive odor characteristic of the birds themselves
(Lane, 1897, 186). Near Corral they are said to nest exclusively in trees,
sometimes in such huge arboreal colonies that the droppings kill all the
vegetation. Hellmayr speaks of a colony of thousands on the summits of the
loftiest trees near a place called Los Guauros, south of Mansera Island in the
Bay of Valdivia.
BIGUA CORMORANT 915
At Pacheca, of the Pearl Islands in the Gulf of Panama, the inner plateau is
thinly wooded, and here Rendahl (1920, 11) found these cormorants nesting in
leafless trees at the end of March. Nearly every tree had several nests. The
cormorants made up a sort of central colony in the general sea bird population,
with pelicans and boobies nesting in separate areas roundabout them. The
cormorants promptly drove out any boobies that attempted to alight within
their territory, but they submitted meekly to similar invasions made by pelicans.
Rendah] found the species common also at Santelmo Island, and Thayer and
Bangs (1905, 141) report them from San Miguel of the same group. The last
authors also speak of a nest in a tree at Saboga which contained six well-
incubated eggs on April 14. This is the largest set of which I find any record.
Stomachs of Cuervos I collected along the coast of Peru contained the follow-
ing species of fishes: Scorpaena histrio, Chromis crusma, Epinephalus labriformis.
One had five or more small examples of the last-named species, together with a
hippa (Emerita analoga), which may have come from the viscera of one of the
fishes. Another contained an unidentified fish 20 centimeters in length, and also
barnacles (Balanus tintinnabulum), crabs, a chiton, other mollusks, and algae,
all of which may likewise have come from the alimentary tract of the fish,
which was partly digested.
A manuscript note by the late Dr. H. C. Forbes states that he saw one of
these cormorants on the coast of Peru capture 22 eels within ten minutes. Since
there are no catadromous eels in this part of the world, the fishes were doubtless
shore-eels (Ophichthus or Gymnothorax), of which I have collected specimens in
Peru. According to Coker (1919, 479), the Cuervo prefers shallow-water
bottom fish which it can capture close to shore, especially such forms as blennies,
which one may see from the rocks in suitable places. He has found in the
stomachs and gullets of the birds fish of this sort, ranging in length between
6 and 25 centimeters. Lane (1897, 186) states that the cormorants sometimes
remain from three to four minutes beneath the surface while hunting food.
Like certain other cormorants, as well as grebes, they can swim at the surface
with only the head exposed. Mr. George K. Cherrie states in manuscript that
in the Rio Paraguay he has frequently seen the Cuervos bring up from the depths
a kind of catfish about 15 centimeters long and armed with strong and sharp
pectoral and dorsal spines. They never attempted to swallow such victims until
they had been tossed and caught again so as to go down head foremost. Verrill
(1923, 303) states that at Paita, Peru, he noted that the Cuervos remained
beneath the surface for from 30 seconds to nearly a minute.
FUEGIAN CORMORANT
Phalacrocorax olivaceus hornensis, new subspecies
Subspecific Characters: Similar to Phalacrocorax olivaceus olivaceus, but with a much shorter
bill, and averaging smaller in all other dimensions except length of tail.
Type.—No. 3609, Brewster-Sanford Coll.; Amer. Mus. Nat. Hist.; @ ad.; Bertrand Island
(south of Navarino Island), Chile, April 22, 1915; R. H. Beck.
Measurements, and other data, covering 4 adults are as follows:
916 OCEANIC BIRDS OF SOUTH AMERICA
; i Exposed |Bill from Outer toe
ese Tail | culmen gape Tarsus land claw
o’, Bertrand Island, Apr. 22,1915. . 281 165 49 79 54 89 mm.
o’, Beagle Channel, July 29,1915. . 281 176 50.5 79 54 92
9, Bertrand Island, Apr. 22,1915. . 265 133 46 70 50 86
9, Beagle Channel, Jan. 11,1915. . 269 148 46 70 51 81
Distribution: Islands and waters in southern Tierra del Fuego and the neighborhood of Cape
Horn; known specifically from Bertrand Island in the Gulf of Nassau and from Beagle Channel;
northern limit of the range not determined.
This well-marked race, which has not previously been distinguished, has
been reported upon from the Magellanic region by many naturalists under the
specific names vigua, brasilianus or brasiliensis. It is presumably the form taken
or observed in various parts of Tierra del Fuego by King (1828, 101), Oustalet
(1891, 142), Dabbene (1902, 395), and Crawshay (1907, 149).
Beck found these cormorants common along all the southerly Fuegian coasts
between July and December, 1914, and collected examples in Beagle Channel
and at Bertrand Island during January, April, and July of the following year.
A female shot on January 11 was practically ready to lay eggs, while the April
and July birds of both sexes had gonads in the resting stage. Notes on the
label state that all the birds had green irides, the bill being black above and
yellowish or brownish on the mandible, the legs and feet black, in all of which
respects they agree with the typical subspecies.
The relatively slight evidence from the sex organs of four adult individuals
indicates exactly what might be expected, namely, that the native Bigiia Cor-
morant of the inclement region close to Cape Horn has a definitely fixed breeding
period, which comes at the beginning of the summer, as opposed to the extended
or continuous breeding season characteristic of the tropical representatives of
the species.
The range of this form remains to be worked out through further collecting.
Practically all of the birds from more northerly parts of South America are, as
previously noted, typical of the subspecies olivacews. A female from the Rio
Gallegos, Patagonia, which is just north of the Strait of Magellan, has, how-
ever, a very short bill (50 millimeters) and may be somewhat intermediate
between the two geographic races. It is worth noting that the Central and
North American race mexicanus, which is even smaller than hornensis, has a
very much longer bill.
FLIGHTLESS CORMORANT
Nannopterum harrisi
Phalacrocorax harrisi Rothschild, 1898, Bull. Brit. Orn. Club, 7, p. 52 (Narborough Island, Galapagos
Archipelago).
Names: Galapagos Cormorant. There are no synonyms of the specific name.
Characters: A gigantic brown cormorant, with diminutive, rounded wings, in which the fifth
from the outermost primary is the longest.
Adults (sexes alike): Entire plumage soft, loose, and hair-like, generally blackish brown,
FLIGHTLESS CORMORANT 917
lighter ventrally; a faint greenish gloss on the scapulars and other parts of the dorsal surface; the
ventral surface varies among seyeral specimens from tawny to seal brown; sides of head and neck
sprinkled with white filoplumes, each of which has a brush-like termination of many loose barbs.
Iris emerald (‘‘clear glittering Italian blue,"’ according to Beebe), the pupil somewhat elliptical,
with the horizontal diameter longer than the vertical (Snodgrass and Heller, 1904, 249); maxilla
blackish or slaty, with the tip and tomia horny brown; mandible horny brown, with darker
tomia; gular sac brownish purple, with whitish dots; lores dusky, with parallel rows of pale dots;
legs and feet black.
Dimensions (based upon two American Museum specimens and published figures of Gifford
and of Snodgrass and Heller):
Males: Length, 905; wing, 186-188; tail, 154-165; exposed culmen, 65-77; bill from gape, 120;
tarsus, 72-79.6; outer toe and claw, 124 mm.
Females: Length, 885; wing, 177.5-193; tail, 149-165; exposed culmen, 59-76.5; bill from gape,
112; tarsus, 59-66; outer toe and claw, 99-110 mm.
I find no descriptions of the young.
The eggs number 2 or 3. They are described as elongate-oval or narrowly elliptical in form,
with a bluish green shell, much concealed by a limy deposit. The extremes among two sets of
3 measure 71 x 42.5, 59 x 41, 68 x 45, and 64 x 39 mm.
Distribution: The Galapagos Archipelago; thus far recorded only from Albemarle and
Narborough Islands.
The Flightless Cormorant of the Galapagos is one of the most striking
examples of genetic loss of function made possible by the safety of isolation.
We need to know nothing about the ultimate place of origin of the species to
realize that at the lonely archipelago where it is still found it has enjoyed for
ages—in the absence of predacious reptiles and mammals—an immunity which
has put no check upon diminishing wing-area and increasing body-weight.
As Beebe (1924, 115) has pointed out, the degeneration of its wings has gone
even further than that of the Great Auk, for those of the cormorant measure
not more than 20 per cent of the total length of the bird. The weight of the
largest cormorant collected by Beebe was 3.85 kilograms; that of a captive
example in good health, 2.5 kilograms (Townsend, 1929, 211).
The fact that this species was unknown to science until just before the
beginning of the present century is somewhat astonishing. Townsend explains
it by inferring that in the water the bird looks much like any other cormorant,
for which reason it would be less likely to attract the attention of a visiting
naturalist than many of the supposedly more extraordinary birds of the Galapa-
gos. On the other hand, it is possible that the range of the cormorant was
highly restricted even during times before dogs were introduced. At present it
is by far the most local in distribution of all the sea birds of the archipelago,
its range being confined to Narborough Island and the adjacent parts of the
coast of Albemarle. Snodgrass and Heller (1904, 249), who were in the field
soon after the date of first description of this cormorant, never saw more than
a dozen of the birds at one time, and wrote: ‘“‘Their small numbers and their
much restricted habitat would seem to indicate that they are on the verge
of extinction.”
The Flightless Cormorants seem to nest altogether on the shores of main
islands of the Galapagos, instead of on outlying rocks as so many of the other
sea fowl do. Nesting groups are small, rarely more than a half dozen pairs,
918 OCEANIC BIRDS OF SOUTH AMERICA
and the birds are not wary enough to retreat to the water when safety demands
it. One of the nesting localities is in Tagus Cove, where most scientific visitors
have anchored. Here Beebe found two nests situated 5 meters apart on pro-
jections of lava on a steep slope from the water. In each of these a bird was
covering a single egg. The nests were well-formed masses of débris from the
cove, chiefly dried seaweed, starfish, and fish bones. At Banks Bay the nests
are described as depressions in the sand, lined around the edges with a few
sticks and seaweed. The birds here protected them savagely, opening their
mouths menacingly and uttering harsh guttural croaks (Gifford, 1913, 80). In
the northeastern part of Narborough, Gifford found two “‘colonies’’ in April.
In one there were three pairs, in the other four or five, the nests lying on black
lava about 3 meters above the water, and each containing either two or three
eggs. Snodgrass and Heller (1904, 249) describe the nests as made of brown
algae heaped into cone-shaped masses about 30 centimeters high, with a hollow
at the top for the eggs. These authors give the following dimensions: external
diameter 75 centimeters; internal diameter 40; depth of cavity 10. They usually
saw the adults in pairs, and observed that the females were particularly stubborn
in defense, thrusting with their beaks and hissing loudly.
In the water the Flightless Cormorants are both efficient and graceful, carry-
ing the neck in very swan-like fashion while they remain at the surface. The
body floats as low as that of an otter, sometimes only the head and part of the
neck being exposed. In sounding, these birds do not merely sink, like a Gala-
pagos Penguin or a seal; rather, they make a rapid upward and forward leap,
then curving under head-first.
Ashore, the large bodies and short legs of the Flightless Cormorants put
them at a great disadvantage. On a level surface they waddle, changing their
method of progression on a rough terrain to a series of springy jumps. They
can leap to the top of a rock 15 to 20 centimeters high, though in this respect
they are far less agile than their little neighbor, the penguin. They are fond of
working their way to some high point on the coast near the nesting sites, there
to sit and sun, with the wings half spread, as vultures do. At such times they
can be all too easily approached, and even killed with a stick.
In captivity at the New York Aquarium, Galapagos Cormorants eagerly
drank seawater. They were extremely quarrelsome, and threatened to kill a
Galapagos Penguin in the same pool. They resented handling or any other
intimacy, and squawked loudly when seized or picked up. While pursuing
food under water, they held the wings close against the body, progression
depending entirely upon the widely webbed feet. After swimming and feeding
in the Aquarium pool, the birds would stand upright and spread their abbre-
viated wings to dry, in the familiar cormorant fashion. They slept standing
on one foot, with head laid diagonally across the back and the beak tucked
under the wing coverts. They jumped well from the height of a table to the
floor. The birds were much interested in their own image in a mirror, or even
in the dim reflection in a bookcase door (Townsend, 1929, 211).
The croaking and hissing of these cormorants has been referred to above.
FLIGHTLESS CORMORANT 919
Bronson (1931, 62) likens their notes to “‘static on the radio."’ Gifford states
that the young are capable of making “‘loud cries’’ when they pursue their
parents in the water to demand food.
A stomach examined in the field by Beebe contained eels, smaller fish, and
a good-sized octopus. The last creature evidently enters heavily into the menu.
Bronson states that a Flightless Cormorant can swallow in rapid succession two
dozen ‘‘seven-inch herring,’’ and Gifford saw one come to the surface and
swallow a ‘14-inch eel.”’
THE MAN-O’-WAR BIRDS
FAMILY FREGATIDAE
In many groups of birds the various related species differ more in the details
of their life history than they do in structure and appearance. Among the
man-o'-war birds the opposite is true. Occupying one part or another of the
warmer oceans of the world are no less than five species, which appear to exhibit
well-marked differences of size and of color pattern, whereas in habits and
ecological position all forms seem to be extremely similar. At a few breeding
stations, such as the island of South Trinidad, two species—one large, one
small—live side by side, and a more exhaustive knowledge of the life history
of each is, of course, likely to bring to light yet undiscovered divergence as to
their respective places in the local web of life.
In view of the extraordinary powers of flight possessed by man-o'-war birds,
it is remarkable that several of the species have developed a number of sub-
species of highly restricted range. Such a condition presumably means that the
breeding stocks have been isolated during long periods of time, which brings
us back to the thesis discussed in an earlier section (p. 91), namely, the essen-
tially sedentary nature of these birds. Stragglers among the man-o'-war birds
have no doubt at rare intervals wandered far and wide, or have been transported
great distances by storms. Only in this manner could remote oceanic islands
have become populated by representatives of the group. With such exceptions,
however, man-o'-war birds cling rather closely to continental or insular coasts
and, indeed, seldom fly out of sight of land. Finsch (1900, 446) has devoted
particular attention to this subject, and the most remote pelagic record he could
find was of a single individual noted during the month of August some 600 to
700 kilometers to southwestward of the Hawaiian group. It should be re-
marked, however, that this position is a much lesser distance from Johnston or
Cornwallis Island. Mr. J. T. Nichols has reported to me by letter on a man-o’-
war bird observed during April in a position ‘‘some 800 sea miles west of the
island of San Felix.’’ Even this point is less distant from the Sala y Gomez
Rocks where, as I have reported earlier, man-o’-war birds nest. In any event,
the great scarcity of pelagic records shows that the man-o’-war birds, like all
of their near relatives except the tropic-birds, are distinctly not “‘ocean wan-
derers.’’ While not as exclusively littoral as the pelicans and cormorants, they
920 OCEANIC BIRDS OF SOUTH AMERICA
at least cling closely to their island homes, and are even less likely to be seen
off soundings than are some of the boobies.
Man-o’-war birds are of pan-tropical distribution. Finsch notes but one
record to southward of the tropic of Capricorn in the central Pacific, and this
was only in latitude 26° 50’ S. The breeding station at Sala y Gomez, consider-
ably farther eastward, is about at the same parallel, but the bird does not appear
to be a resident of Easter Island. The northward bend of the Sub-Tropical Con-
vergence, as the South American coast is approached, bars it, of course, from
San Felix and San Ambrosio. In the western South Pacific no man-o’-war birds
inhabit the Kermadecs, Norfolk or Lord Howe Island, and the few New Zealand
records are evidently based upon accidental occurrences. In order to pass from
the South Atlantic to the Indian Ocean, or vice versa, it would be necessary for
man-o’-war birds to cross the 35th parallel of south latitude, but it is of zodgeo-
graphical interest to note that they might do so without crossing or even
closely approaching the Sub-Tropical Convergence, which loops sharply south-
ward off the southern tip of Africa (Fig. 6). Between the Atlantic and the
Pacific the only direct route available within recent epochs of earth history
would be across the Isthmus of Panama. This, however, imposes no effective
barrier, for man-o'-war birds constantly fly back and forth from one ocean to
another as, indeed, they do over lands much higher and twice as wide, such
as the island of Cuba.
In the light of present knowledge, the following species and races of man-o’-
war birds occur within the South American region, or at the more or less remote
islands of the South Atlantic which I have included within my geographical
discussions.
1. Fregata aquila Linnaeus.
Type locality, Ascension Island.
This species is confined entirely to Ascension, and has not been recorded from
anywhere near the South American coast. Formerly, however, the specific
name aquila was applied to frigate-birds from all parts of the world, so that it
appears much in the synonymy of other forms of the genus.
2. Fregata magnificens magnificens Mathews.
Type locality, Barrington Island, Galapagos Archipelago; also recorded
from Indefatigable, Albemarle, Duncan, and Hood Islands.
Peters (1931, 95) states that this race breeds also at the Pearl Islands in the
Gulf of Panama. In view of the fact that the Caribbean Man-o'-war Bird is
regarded as a distinct race, and that individuals and bands regularly and con-
stantly pass back and forth between the Pacific and the Caribbean, it would
be biologically inconceivable that separate races exist on the Atlantic and
Pacific coasts of the Isthmus. It is much more likely that this large Pacific race
is confined exclusively to the Galapagos Islands, from which it never wanders
as far as the coast of the continent. I have no knowledge as to whether it is
this form or another which inhabits Cocos Island.
THE MAN-O-WAR BIRDS 921
3. Fregata magnificens rothschildi Mathews.
Type locality, Aruba Island. Distribution, southern Florida, the Bahamas,
West Indies, all coasts of the Gulf of Mexico, the Caribbean Sea, and the South At-
lantic Ocean southward to Fernando Noronha and islands along the eastern coast
of Brazil; also along the Pacific coast of America from Mexico to northern Peru.
I judge that Fregata minor januaria, described by Ribeiro from the littoral of
Brazil between Rio de Janeiro and Santos, is identical with this form, and not
with the larger of the two frigate-birds inhabiting South Trinidad Island. At
any rate, all the specimens I have seen from the coast of Brazil prove to be
me gnificens rather than minor.
4. Fregata minor ridgwayi Mathews.
Type locality, Culpepper Island, Galapagos Archipelago; recorded also from
Wenman and Hood Islands.
Swarth (1931, 39) has shown that the two breeding species of man-o’-war
birds in the Galapagos are at the same time closely associated and readily dis-
tinguishable, and that there is probably a general segregation of breeding
grounds between the two, even though both apparently occur throughout the
archipelago. It is almost certain that magnificens is an Atlantic derivative dat-
ing, like the Red-billed Tropic-bird, Brown Pelican, Yellow-crowned Night
Heron, Flamingo, etc., from the time when the Galapagos were in an oceano-
graphic sense an outpost of the West Indies. Fregata minor, on the other hand,
probably reached the Galapagos from the west or southwest, for it is a circum-
polar species throughout a pan-tropical belt of the southern hemisphere.
Although the two species of man-o'-war birds at the Galapagos present no
difficulties when it comes to distinguishing one from the other, it cannot be
said that the peculiar characters of the resident subspecies of minor have been
very Clearly pointed out. Fregata minor ridgwayi, as shown by Swarth, has been
collected once to northward of Clipperton Island but, according to the ‘‘A. O. U.
Check-List of North American Birds’’ (1931, 25), all available Lower Californian
specimens prove to belong to the species magnificens.
5. Fregata minor nicolli Mathews.
Type locality, South Trinidad.
Known only from South Trinidad and the neighboring Martin Vas Islets.
As noted above, this form apparently does not wander to the Brazilian coast.
). Fregata ariel trinitatis Ribeiro.
Type locality, South Trinidad.
Restricted to South Trinidad and Martin Vas. This race of the Lesser Frigate-
ird is the only Atlantic representative of a species of world-wide distribution
1 warmer waters of the southern hemisphere, and it also crosses the equator in
nie Western part of the Pacific.
. Doubtful forms.
r It should be pointed out here that the island of St. Helena, in the eastern
fab-tropical Atlantic, was formerly inhabited by some form of man-o'-war bird,
922 OCEANIC; BIRDS, OF SOUTHVAMERICA
which seems to have become extinct before any specimens were preserved. With
the ranges of no less than four species approaching this island from the directions
of South Trinidad, Ascension, and Gambia, it would be unprofitable to speculate
as to what the affinities of the St. Helena bird may have been.
Finally, I have had no opportunity to examine any man-o’-war birds from
Cocos Island, and am therefore uncertain as to whether the resident form is a
representative of magnificens or of minor. Gifford (1913, 103), working in the
field at a date when the two were not distinguished, found them common
during September in the tall forest trees of Cocos. They were persecuting not
only the boobies but also the smaller noddies. No specimens were collected.
The man-o’-war birds exhibit specific differences which should be the delight
of a geneticist, for every one of them represents a combination of characters of
a sort which has appeared many times in breeding stocks of laboratory animals.
Among these birds, for example, one sees evidence of mutations which have
produced ‘‘cock-feathered hens’’ and also “‘hen-feathered cocks.’’ Every adult
man-o'-war bird, in fact, wears a plumage representative of a stage in the ontog-
eny of some other man-o’-war bird. No ornithologist has ever attempted to
split the group into two or more genera, and it seems probable that all the
forms in the world are very closely related, and that they have become differen-
tiated through simple and comprehensible types of genetic mutation, which
have affected the size, proportions, and plumage-pattern of each.
In using the adjective ‘‘simple,’’ I mean merely that the results are extraor-
dinarily understandable by analogy with those of controlled breeding experi-
ments in other animals. The mutations involved may well be very numerous,
for in the domestic fowl] at least a dozen genes which modify the pigmentation
of feathers have been discovered. Such a phenomenon as cock-feathering ip a
female bird, moreover, may occur in two or more ways. In the mallard duck,
for example, a secretion of the ovaries inhibits development of the basic plu-
mage-pattern which is similar to that of the male. Ovariectomy removes this
check and the female will then become drake-feathered after the next moult.
Among other species, cock-feathering in the female is due to a gene which
affects the chromosomal content of the skin cells, and the gonads are not con-
cerned with the visible results. A brief analysis of plumage-patterns in the five
species of the genus Fregata is as follows:
In juvenal plumage all of them look much alike, except as regards size, eac
having a white head, neck, and breast, and a pronounced light-colored ale
bar, regardless of sex. The males of two species, namely, magnificens and aquil.
change from the last-named plumage to a completely black garb, relieved on
by iridescence which is mainly violet in the former species and mainly gre
in the latter.
The female of magnificens, however, retains the alar bar and white breast
juvenal plumage, whereas the female of aquila becomes a cock-feathered bir
although in the distinctly paler brown of its breast and hind neck, and in
vague brownish tinge along the ulnar coverts, it retains what might be call
a palimpsest of the juvenal pattern.
Fic. 72. Plumage-patterns, in ventral and dorsal aspect, among several ages and species of
Man-o'-war Birds.
Reading from left to right: upper two, Fregata magnificens magnificens, adult 9, and F. magnificens
rothschildi, young 9; middle two, F. aquila, adult @ and 9; lower two, F. minor, adult @, and
F. ariel, adult #.
[ 923 ]
924 OCEANIC BIRDS OF SOUTH AMERICA
The adult male of minor, on the other hand, retains the brown wing band
which is universally characteristic of immaturity and generally of femininity,
while its mate is only slightly differentiated from the female of magnificens.
In still another species, which does not come within the scope of this book,
namely, Fregata andrewsi of the Indian Ocean, adults of both sexes have taken
the opposite genetic trend from that of aquila. In other words, not only does
the female of this species retain the feminine type of plumage, but the adult
male is also hen-feathered, keeping both a wing-bar and a white abdomen.
Finally, the female of the species ariel has the usual pattern of its sex, while
the male has made a new departure in plumage experimentation, and has
developed conspicuous white spots on either side of its black ventral plumage.
Throughout the family, of course, the principal secondary sexual character,
which is the brightly colored, inflatable gular sac, is restricted to males. Vigors
(1833) reports upon a dissection by Collie, surgeon of H. M. S. ‘Blossom,’
which purports to show that the pouch of the man-o’-war bird is inflated from
the lungs through an opening anterior to the humeral articulation of the
scapula. From here, in the cellular substance beneath the skin, a passage of
some length leads from the bony orifice to the pouch. A modern reéxamination
of this mechanism is much needed.
As a flying-machine, the man-o’-war bird is unparalleled in nature. Among
all birds it has the greatest plane area in proportion to weight. Furthermore,
its plumage and pectoral muscles together make up at least 47 per cent of the
total body-weight.
ASCENSION MAN-O’-WAR BIRD
Fregata aquila
Pelecanus Aquilus Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 133 (Ascension Island).
Names: Ascension Frigate-bird.
Characters: A relatively small-billed man-o’-war bird, and the only species in which the adult
female is entirely dark.
Adult male: Black, with glossy metallic sheen on much of the plumage, this being mainly
bluish green on the lanceolate feathers of the head, and bottle-green, with only a slight admixture
of bronzy or purplish, on those of the back; breast and belly duller, with a suggestion of brownish,
but still never without slight bronze, purplish, or dark bluish reflections; shafts of wing quills
dark, but those of the tail ivory-white in ventral aspect. Iris brown; gular sac red; feet apparently
black. Alexander (1928, 264) states that the feet of the male are red. Among our dried specimens,
however, they look black, whereas those of the female are red, as in F. magnificens.
Adult female: Similar to male, and only slightly less glossy green on the back where, however,
the feathers are less distinctly lanceolate; the breast, furthermore, is distinctly brown, without
trace of metallic iridescence, and an extension of this area forms an indistinct brownish collar
around the hind neck; a faint suggestion of a brownish alar bar is also usually perceptible. Feet red.
5 males: wing, 552-581 (562); tail, 357-402 (384); exposed culmen, 87.3-95.5 (91.7); width
of maxilla at base (average), 29; middle toe and claw, 65; length in the flesh, 891; wing-expanse,
1957 mm.
4 females: wing, 587-607 (598); tail, 393-411 (405); exposed culmen, 99-105.9 (103); width of
maxilla at base, 34; length in the flesh, 960; wing-expanse, 2055 mm.
The juvenal plumage is at first nearly indistinguishable from that of magnificens, the resemblance
extending even to the pronounced grayish alar bar. An incomplete brownish collar, however,
terminates in large patches at the side of the breast, which ultimately turns entirely dark.
ASCENSION MAN-O’-WAR BIRD 925
Nestlings and eggs not seen.
Distribution: Known only from Ascension and the adjacent waters. The principal breeding
center is at Boatswain-bird Islet.
The name of the typical species of the man-o’-war bird is the Latin adjective
signifying dark-colored, and not the noun meaning eagle. Possibly Linnaeus
knew that both sexes of the Ascension bird are black, but for much more than
a century after the original description his specific name, Pelecanus aquilus, was
made to cover practically all forms of man-o’-war birds the world over.
The Ascension bird has always been rather little known, and very rare in
collections, but the American Museum now fortunately possesses nine speci-
mens collected in November, 1925, during the South Atlantic Expedition of
the Cleveland Museum of Natural History. The species proves to have a curious
diagnostic character in its slender and remarkably depressed bill, the culmini-
corn plate of which is extraordinarily flat, rising little if any above the plane
of the latericorn plates on either side. The depth of the closed bill at its mid-
point averages 14 millimeters among 5 females; among 21 females of Fregata
magnificens rothschildi this same measurement averages 17.6 millimeters. The
cock-feathered plumage of the female of the species aqguila, which is unique in
the genus, has been sufficiently referred to in the introductory section.
More than a century ago, Burton (1822, 1) collected several man-o’-war
birds at Ascension where, he states, they were breeding in vast numbers during
the month of September, and made some interesting comments upon the mor-
phology and life history of the species. Not unnaturally, he mistook the adult
females for males, which they so much resemble, and assumed that the im-
mature birds, collected over the surrounding ocean, were females.
Average measurements in centimeters of five mature examples, presumably
including both sexes, Burton found to be as follows: length of body (tip of beak
to tip of tail), 91; wing-expanse, 208; length of extended wing, 98; length of
longest primary quill, 43. The weight was 1247 grams, of which the pectoral
muscles alone made up “‘nearly one-fourth.’ The weight of the plumage of an
example, derived by weighing the body before and after plucking, amounted
to 283.5 grams. Regarding the extraordinary disproportion between the pec-
toral and pelvic members of these birds, to which Burton devotes considerable
discussion, he records the following interesting data:
Humerus: length, 184 millimeters; weight, 11.34 grams.
Ulna and radius: length, 241 millimeters.
Femur: length, 51 millimeters; weight, 0.713 grams.
Tibia: length, 57 millimeters.
Burton calls attention to the fact that the preen gland, which is no larger
than a “‘garden pea,”’ is in this species totally insufficient for its usual office
among sea fowl and that, in correlation with this, the plumage of man-o’-war
birds immediately became water-soaked when they were placed upon the ocean.
Uninjured birds, moreover, could make no progress whatsoever by swimming.
The tail, he writes, is the most important organ in the aérial gyrations required
926 OCEANIC BIRDS OF SOUTH AMERICA
by the habits of man-o’-war birds, such as the “flattening out’’ by means of
which they suddenly check their breathless descent when darting straight down
from a great height toward the water. The tail is regulated by seven distinct
pairs of muscles leading to the caudal vertebrae, and the enormous rectrices are
inserted in an exceedingly massive cushion of tissue on either side of the huge
py gostyle.
A downy chick examined in the nest by Burton disgorged seven flying fish.
Moseley (1879, 563), Penrose (1879, 276), and Simmons (1927, 51) have
described the nesting of the Ascension Man-o'-war Bird at Boatswain-bird
Islet. The plateau is fairly flat, with an area of roughly 8000 square meters
(2 acres), and here the birds apparently breed throughout the year, for the
‘Challenger’ party found them on the nests in March and April, and the ‘Blos-
som’ party in November. So far as can be judged from the literature, no nest-
structure is built up, the egg being deposited in a hollow of the islet’s guano-
crust. Penrose states that the birds have considerable difficulty in rising from
the ground, but the remarkable point is that they are able to take wing at all
from such a flat surface, for other species of man-o’-war birds are generally
credited with being helpless under similar circumstances. Photographs accom-
panying the text of Simmons show the nature of the terrain, which has few
projections or irregularities.
It is likely that this species inhabited the main island of Ascension during
the remote time when it was wooded, and that the birds now occupy the small
outlier because they can always take wing by floundering to the readily acces-
sible brink of the cliff.
Schlegel (1863, 2) tells of an Ascension Frigate-bird which attempted
obstinately to tear the pennant from the masthead of his ship, a trait which has
also been reported of other species. Ascension is a famous breeding ground for
sea turtles, and the man-o’-war birds are said to devour many of the newly
hatched young. I have no satisfactory testimony, however, as to whether the
baby reptiles are picked up from the beaches or only from the surface of the
water. The question is referred to again in the biography of the next species.
GALAPAGOS MAN-O’-WAR BIRD
Fregata magnificens magnificens
Fregata minor magnificens Mathews, 1914, Austr. Avian. Rec., 2, p. 120 (Barrington Island, Galapagos
Archipelago).
Names: The commonest synonym in the literature of this, as of most other forms of man-o’-war
birds, is aquéla.
Characters: A sexually dimorphic species, the adult male with wholly black plumage, the
female white-breasted. This is also the largest race of the largest species of man-o'-war bird.
Adult male: Entirely black except on the unfeathered parts, the lanceolate feathers of the
pileum glossed with metallic bottle-green, those of the scapulars and interscapulars with both
green and reddish purple, but with the latter predominating; the coverts of the wing also have a
similar gloss, with green predominating, while the duskier plumage of the ventral surface has a
less pronounced purplish gloss. Iris brown; bill blackish horn-color or leaden blue, usually with
more or less of a flaky crust similar to that on a pelican’s bill; gular sac bright red, with small,
GALAPAGOS MAN-O’-WAR BIRD 927
warty, orange excrescences, during the courtship season, subsequently shrinking so that the surface
is prevailingly orange; legs and feet black.
Adult female: Head, neck, and dorsal surface, lower belly and crissum, brownish black, darkest
on the crown and the quills; lanceolate feathers of the crown only slightly glossed with green;
feathers of scapular region not lanceolate and very slightly glossed; breast, base of neck laterally,
and flanks, white, with an indistinct grayish collar passing around neck from the white area;
central lesser wing coverts grayish brown, forming a broad and somewhat ill-defined bar along
the anterior edge of the mid-wing; quills of wing and tail faintly glossed with blue and purple
hues. Bill horn-color; bare throat dusky purplish; orbital skin dark blue; legs and feet red, pink,
or Magenta.
One male, Indefatigable Island: wing, 651; tail, 465; exposed culmen, 111.2; width of maxilla
at base, 32.1; middle toe and claw, 69 mm.
One female, Indefatigable Island: wing, 703; tail, 543; culmen, 125.7; width of maxilla at
base, 35; middle toe and claw, 75 mm.
Young: Head, neck, breast, and belly white, usually with a brownish extension from the
flanks more or less meeting across the breast; remainder of plumage much as in the adult female;
gular sac lavender-blue; feet flesh color.
Nestling: Covered with fluffy, booby-like white down, from which it moults directly into
the juvenal plumage described above, the first contour plumage to appear being the clove-brown
feathers of the back and scapulars. The first white feathers on the head are usually tinged with a
rusty hue. The quills are glossy black. The ashy lesser coverts of the wing form the broad band
which is characteristic of juvenal and adult female plumages.
I have not seen eggs of Galapagos Man-o'-war Birds, and the descriptions and measurements
published by Gifford include those of two distinct species.
Distribution: The Galapagos Archipelago, probably throughout the group, but specifically
recorded from Barrington, Indefatigable, Albemarle, Duncan, and Hood Islands.
At the Galapagos Islands, the Atlantic-Caribbean species of man-o'-war bird
reaches its westernmost outpost. The local birds seem to comprise an exception-
ally large subspecies, which is presumably endemic. No specimens from the
west coast of South America, or from Panama, at any rate, appear to equal them
in size. The large dimensions are illustrated by the two specimens in the
American Museum Collection, the female of this random pair being the largest
man-o'-war bird among the more than 70 examples I have measured. Gifford
(1913, 104) has recorded the measurements of many other specimens but, as
pointed out by Swarth (1931, 39), he has confused representatives of this species
with those of the Galapagos race of Fregata minor, so that the measurements of
these dissimilar birds are combined.
Notes on the life history of the Galapagos race of Fregata magnificens are
included in the next biography, which deals with the very closely related con-
tinental and Antillean subspecies.
CARIBBEAN MAN-O’-WAR BIRD
Fregata magnificens rothschildt
Fregata minor rothschildi Mathews, 1915, Birds Austral., 4, p. 280 (Aruba Island, Caribbean Sea).
Names: Frigate-bird, Man-o’-war Hawk. Spanish-American names include ‘‘Tijera,”’
“Tijereta,’’ ‘’Tijerilla,"’ ‘‘Rabijunco,’’ ‘‘Rabihorcado,”’ and ‘‘Anunciador."’ In Brazil the names
““Grapira,’’ ‘‘Tesoura,’’ ‘‘Tesoureira,’’ and ‘‘Jodo Grande’’ are used. The specific names aquila
and minor have both been applied to this form.
Subspecific characters: Similar in all respects to the typical subspecies, but smaller.
928 OCEANIC BIRDS OF SOUTH AMERICA
21 males from Florida, the Bahamas, the Lesser Antilles, Santo Domingo, Porto Rico, Texas,
Vera Cruz, Honduras, Panama, Ecuador, northern Peru, Fernando Noronha Island, and Rio de
Janeiro: wing, 611-661 (633); tail, 339-472 (431); exposed culmen, 105.2-118.5 (112.1); width of
maxilla at base, 30.2-32.5 (31.4); tarsus, 21-25 (22.4); middle toe and claw, 69-74 (71) mm.
The length in the flesh of 5 males was 93-104 (99.5) cm.; wing-spread of the same birds, 217-
229 (224) cm.
21 females from the same regions as the males and also from Lower California and Sinaloa,
Mexico: wing, 628-674 (650); tail, 504-506 (431); exposed culmen, 109.2-130 (121); width of
maxilla at base, 32-35 (33); tarsus, 21-25 (22.9); middle toe and claw, 71-80 (75.6) mm.
The length in the flesh of 3 females was 94-112 (103) cm.; wing-spread of the same birds, 224-
236 (231) cm.
A female which I shot at Talara, Peru, on January 20, 1925, had a wing-spread of 230 cm. and
a weight of 1587 grams. The dried skeleton of another female weighs 103 grams.
The single egg is approximately elliptical-ovate, and dead white, with a very thin shell.
Measurements of 50 average 68.4 x 46.5 mm., those exhibiting the extremes measuring 74 x 48.5,
72.5 x 50, 64.5 x 46, and 66.5 x 43.5 mm. (Bent, 1922, 309).
Distribution: Atlantic and Pacific coasts of America throughout the extent of tropical littoral;
breeding on the Pacific side from the Gulf of Guayaquil, Ecuador, to Central America (southern
Mexico 2), and on the Atlantic side from the vicinity of Rio de Janeiro, Brazil, to Florida and the
Bahamas; breeding also at Fernando Noronha and throughout the West Indies and the islands of
the Caribbean Sea.
The man-o’-war bird described under the specific name magnificens is chiefly
of tropical American range, although it also crosses the Atlantic to the west
coast of Africa. Lowe has referred to it as a species of the “‘American Medi-
terranean,’’ by which he evidently means the Caribbean-Gulf of Mexico region,
together with a section of the Atlantic to eastward and another of the Pacific
to westward. Its distribution in a north-south direction is widest along the
Atlantic littoral of America, where the limits are approximately in latitudes
25° N..and 25° S.
A number of subspecies have been described, of which three are likely to
stand the test of further taxonomic research, namely, Fregata magnificens magnt-
ficens of the Galapagos Archipelago, F. m. rothschildi of the Antilles and both
the Atlantic and the Pacific coasts of America, and F. m. lowei of the Cape Verde
Islands and adjacent parts of the African coast. Only the first two of these need
here concern us, and I am combining the accounts of their life histories.
In much of the literature, man-o'-war birds of the species minor are listed
from the Pacific coast of America. A form of minor does, indeed, inhabit the
Galapagos Islands, but there is thus far no evidence that its range approaches
nearer toward the continental shores. At any rate, the man-o’-war birds I have
examined from Lower California, Sinaloa, the Gulf of Panama, Ecuador, and
northern Peru are all representatives of magnificens and are indistinguishable
from specimens of West Indian origin.
In the headings I have called the two American races of Fregata magnificens
the Galapagos Man-o'-war Bird and the Caribbean Man-o’-war Bird. Unfor-
tunately, there are no really vernacular names for either of these, unless one
might select one of the South American Spanish or Portuguese terms connoting
‘scissors’ and referring to the manner in which these great sea fowl open and
shut the long blades of their tails. For the species as a whole I am reluctantly
CARIBBEAN MAN-O’-WAR BIRD 929
driven to adopting the name ‘‘Magnificent Man-o’-war Bird,’’ which has
already been used by Alexander (1928, 263).
The Magnificent Man-o'-war Bird is, then, a species of South American
tropical coasts and certain outlying islands. However, the most distant and
isolated islands within the range, such as the Galapagos and the Cape Verdes,
have segregated populations which comprise endemic subspecies. In the coastal
region the species ranges from the neighborhood of Paita, Peru (5° S.), north-
ward and eastward around the continent, and southward on the east coast well
beyond Santos, Brazil. It exemplifies diagrammatically the effect of cool and
warm currents upon zodlogical distribution. The Humboldt Current, for
example, holds it back on the western side of the continent; the Brazil Current,
on the eastern side, carries it southward across the tropic of Capricorn into
higher latitudes than man-o’-war birds customarily inhabit in other parts of
the world. The most distant point from the continental coast that it reaches
to southward of the equator is the island of Fernando Noronha. I have given
above sufficient information regarding its distribution to northward of our
region where, for example, Gulf Stream influences carry it slightly farther from
the equator than any point attained in the southern hemisphere. It is interesting
to note that in South America the distribution of the Magnificent Man-o’-war
Birds exactly supplements that of such a species as Sterna hirundinacea (Fig. 23).
The ranges of these two sea birds begin and end at about the same points on the
Atlantic and Pacific coasts of the continent, but that of the tern symbolizes the
cool-water route by way of Cape Horn, while that of the man-o’-war bird
stands equally for the littoral zone of the tropics.
On the voyage from the Rio de la Plata toward Rio de Janeiro, Mr. Beck
first encountered Man-o’-war Birds near Santos, on February 18, 1916. Other
records from the southerly Brazilian coast include those of Burmeister (1856,
459), Bryce (1912, 371), and Friedmann (1927, 148). Cassin (1858, 358) reports
the species as common in the harbor of Rio de Janeiro, and Burmeister notes that
it nests on uninhabited islets outside. Fitz Roy (1839, 65) found it to be a
resident of the Abrolhos Islets in March, and from this same locality I have
examined two specimens collected during December. Goeldi (1894, 596), who
found the birds nesting at many places along Brazilian shores, also states that
he had only once seen an example more than about 30 kilometers out at sea.
In British Guiana, according to Schomburgk (1848, 763), the Man-o'-war
Bird is seen periodically along the muddy coast and in the estuaries of the rivers.
Breeding stations, if they exist at all, are probably on islands off the French
colony. Farther northwestward, Schomburgk adds, hundreds of the birds may’
sometimes be seen passing inland at dusk in order to roost among the mangroves
or in the taller forest behind them. Beebe (1909, 79) found them common for a
short distance up the estuaries of the Orinoco, and yet Chubb (1916, 202)
assures us that there is no nesting colony in British Guiana.
Throughout the length of the Caribbean, from Trinidad to the Isthmus,
Man-o’-war Birds are everywhere in evidence, not only over the ocean but
sometimes soaring with Black Vultures at great heights over the hor plains
930 OCEANIC BIRDS OF SOUTH AMERICA
and cactus thickets of the mainland (Robinson and Richmond, 1895, 653). They
breed at many islands, such as Orquilla of the Hermanos group and Little Swan,
nesting according to circumstances either in shrubbery, the tops of tall trees, or
on hummocks of grass barely above the ground (Lowe, 1911, 213).
On the Pacific side, the closest colonies to Panama are perhaps those of the
Pearl Islands. Rendahl (1920, 11) found that Cangrejo Island of this group was
the breeding ground of several hundred, and Sturgis (1928, pl. 8) publishes a
photograph showing large numbers of nesting Man-o’-war Birds on Pacheca
Island. From this vicinity southward along the Colombian and Ecuadorian
coasts as far as E] Muerto Island in the Gulf of Guayaquil, the Man-o'-war
Birds doubtless find abundant nesting sites, for the birds themselves are every-
where. At La Plata Island, Ecuador, during February, 1925, the lighthouse
keeper informed me that their nests with eggs had covered the shrubbery at the
southeast point of the island during the preceding October. At El Muerto I
found them plentiful, roosting in dense groups on the bushy tops and slopes of
the islet, but not a pair was nesting in the early months of 1925, doubtless
because of the deluges of that year, which thoroughly interfered with the
breeding of many of the local sea birds. At the bare islet of Pelado, in Santa
Elena Bay, I saw for the first time many Man-o’-war Birds actually on the
ground. They were perching, in fact, all around the edges of the cliffs of this
island on February 14, 1925. Indian fishermen informed me that Pelado was a
breeding station, the nests being built up from the plateau with twigs carried
across from the mainland; at the time of my visit, however, the daily rains were
of such violence as to wash all such structures, together with the guano that
had covered the surface of Pelado, into the Bay of Santa Elena.
To southward of the Gulf of Guayaquil the Man-o'-war Bird appears to be
merely a rover. It is seen regularly down the desert coast to Talara and Point
Parifias, and is not uncommon at Paita and in the Bay of Sechura. During the
annual period of countercurrent activity that takes place after the beginning of
summer, a few of the birds follow the warmer waters down to Lobos de Tierra,
where I saw one on January 9, 1920, to Eten and Pacasmayo on the mainland
coast, and at rare intervals even as far as Salaverry. Latitude 6° S., in the neigh-
borhood of Point Aguja, is probably the southernmost point at which Man-o’-
war Birds may be expected in numbers and with regularity between January and
March or April of normal years.
Green (1887, 41) states that the pectoral muscles of a Man-o'-war Bird equal
one-fourth of the weight of the body, and that the wings are proportionately
larger than those of any other bird: According to Beebe (1924, 321), examples
of this species have forty remiges, as against the thirty of a gull, while the
wing-expanse is nearly 40 per cent greater than that of a booby of only slightly
lesser bulk. Despite this equipment, the Man-o’-war Bird can only take flight
readily from the edge of a cliff or from the elevation afforded by a tree or bush.
Once in the air, it is at ease, and it can withstand wind that would wreck many
another strong flier. During a terrific February storm on the east coast of
Florida, Bangs (1902, 395) observed Man-o’-war Birds cutting into the teeth
CARIBBEAN MAN-O’-WAR BIRD 931
of the gale, or driving before it, apparently without any sense of being incom-
moded. Wayne (1894, 85) states that during a late August hurricane on the
South Carolina coast, the Man-o'-war Birds were not beaten down, even though
pelicans were strewn along the beach for miles. Cyclonic storms are, neverthe-
less, important agencies in the distribution of Man-o’-war Birds, and Reid
(1884, 263) has noted that the Bermuda records of the species have usually been
made after the passage of late summer “‘twisters’’ from the West Indies.
The breeding period of the Magnificent Man-o’-war Bird, like that of many
other tropical oceanic species, is continuous, though at many localities the
season tends to become more or less dated with reference to cycles of wind and
rainfall. Certain tropical colonies seem to be well filled with breeders through-
out the year, and at some of these points of concentration it is doubtful whether
there would be room enough for the nests if all the wanderers along adjacent
coasts were to return for reproduction at the same time. One of the advantages
of all-the-year nesting is that it provides for the multiple use of breeding terri-
tory at such small rocks and islets as may comprise the principal headquarters
of a species.
As among the boobies, the female Man-o’-war Bird is larger than the male,
although this size difference is by no means accompanied by the type of plumage
reversal that one finds among the phalaropes. The male Man-o’-war Bird of
the species magnificens retains at least his superior brilliance in coloration. There
is much evidence, nevertheless, that the female is the dominant member of the
family, and that the male accepts the greater burden of nest-care and incubation.
Some of the best observations bearing upon this question have been made at
the Galapagos Islands by naturalists who failed to distinguish between the
two resident species, magnificens and minor, recording their notes, indeed, under
the old comprehensive name Fregata aquila. The error is not likely to prove of
great importance, however, because the mating and nesting customs of both
species are probably very similar in pattern. Beck (1904, 5) and Beebe give
the impression that the selection of territory is made mainly by the males,
which carry the first twigs to the tops of the dense interlocking branches of
shrubs, and then blow up their brilliant red pouches and display to the utmost,
either as a means of warning off other males, of attracting females, or both.
Inflation of the pouch is accomplished by a pumping, gulping action, as the
air from the lungs comes through its small lumen. The exact manner in which
a female is attracted to a particular male does not seem to be known. Beck,
however, observed behavior which led him to believe that the birds are more
or less polyandrous, or at least that during early stages of courtship the females
divide their responses among several suitors. Both birds of the pair take part
in nest-construction, but the females do most of the carrying, for if the males
fail to stand constant guard other Man-o’-war Birds swoop down and quickly
purloin all of their sticks and twigs so that within three minutes not a vestige
of a nest remains. The twigs are acquired in various ways— either by being
picked up from the ground as the birds sweep by in flight, being snapped off
the tips of dead stalks and branches, being gathered from old or unwatched
932 OCEANIC BIRDS OF SOUTH AMERICA
nests, or being stolen from such boobies as may be carrying them home for pur-
poses of their own. The boobies seem to have full realization of what their
persecutors are after when a nest-making Man-o’-war Bird gives chase, or per-
haps they realize that by dropping a stick they may at least save their dinners.
When the nest platform has been completed, the male continues to sit upon
it with the red balloon fully distended, even while he appears to be sound
asleep. At the descent of a female to the nest, the male will rise to a backward-
leaning posture, with the female sitting similarly in front of him. Both birds
then raise their bills, spread out their long wings over the adjacent shrubbery,
and wave the heads and roll the bodies while emitting resonant gurgling or
chuckling notes. At the same time the pointed, iridescent scapular feathers
stand up like bristles, and both members of the pair swell and tremble with an
amorous ardor, of which the gorgeous red globe of the male is the most striking
symbol. Pairing takes place on the nest as the climax of such demonstrations.
When a courting male leaves the nest, the balloon is slow to collapse. Being
caught by the wind, or perhaps merely offering an awkward resistance to the
wind, it causes the bird to wobble about in a strange manner. The whole
business of an inflated sac ceases with the beginning of egg-laying. Beebe found
that a bulbous pouch invariably meant an empty nest, while a deflated pouch
signified that the male was covering the egg. Furthermore, the red color of the
ornament fades as soon as its annual function is fulfilled, and it becomes pale
orange.
Rarely, two eggs or even two well-grown chicks have been found in the
same Man-o'-war Bird nest, but it is not known whether the production of
such was by one or two pairs of parents. Beebe made the interesting observation
at the Galapagos that yearling young still attempt during the courtship season
to associate with and solicit food from their parents which, of course, have
lost every trace of interest in the younger generation by the time the new
breeding season has begun.
Both sexes share the duty of incubation and brooding, but Chapman (1908,
148) noted at the Bahamas that there seems to be no regularity as to when each
member of a pair takes its post. Other observers, on the contrary, have found
that the hours may be apportioned according to a fairly definite schedule, with
the males bearing the brunt. Beebe reports that at the Galapagos it was the
custom of the males to sit during the morning while their mates were fishing,
and that when his vessel approached Tower Island hundreds of female Man-o’-
war Birds kept company overhead, with not a single male among them.
As already noted, the nests of Man-o’-war Birds are variously situated ac-
cording to circumstance. In some localities, as at Bimini in the Bahamas, they
are placed upon such dense thickets of cactus that it is impossible to approach
near them from any direction (Cory, 1880, 200). At Little Swan Island, Lowe
(1911, 213) found them in the very tops of trees 10 meters tall, among which a
number of dead adults, suspended by their necks from forked branches, told of
the hazards of such sites. He saw the birds, in fact, frequently lose their balance
on the unstable twigs of these tree tops, sometimes tumbling through to come
CARIBBEAN MAN-O'-WAR BIRD 933
slithering down from branch to branch to the rock-heaped ground underneath,
where they were in a sorry plight. Any frigate-bird on the ground is a helpless
creature unless it can scuffle or climb to some jumping-off place. The islanders
living at Orquilla informed Lowe that if one chances to fall into the water, it
experiences enormous difficulty in rising again unless a fresh breeze is blowing.
As a matter of fact, I can find not a single authenticated reference to a Man-o’-
war Bird alighting on the water, or swimming or floating, except when
wounded. Gifford states that if one of these birds is forcibly immersed its
feathers become soaked within a very short time. The creature thus seems to
occupy the same place in the Pelecaniform group that the Sooty Tern does
within its family, both scrupulously avoiding getting their feathers wet.
At the nesting ground the Man-o’-war Birds are quite tame. In spite of their
formidable bills, says Lowe, they are the most mild mannered of all sea fowl.
Not only do they become conditioned to sit tight on the nests when men ap-
proach and touch them but, moreover, with their close neighbors, the boobies,
they behave as though nothing had ever occurred to mar the eternal friendship
between the two. Nesting boobies and Man-o’-war Birds, a meter or two
apart, pay rather less attention to each other than either would to members of
its own species. The change in behavior when the boobies are returning to
the nesting ground well laden with fish is most extraordinary, and it indicates
how wholly the reactions of birds are determined by the stimulus of the moment,
which retains neither place nor meaning in their consciousness after that
moment has passed.
In robbing other birds, the Man-o'-war freebooters pursue them singly or
in pairs, following with the utmost agility every gyration of the victim, and
usually continuing the chase until disgorging has been forced. Then the robber
tips forward and catches the secondhand fish in air. The terrorization of boobies,
and the recovery of the ejected prize, was described by Columbus in the log of
his first voyage of discovery. During such pursuits, the Man-o’-war Bird does
not hesitate to apply stronger persuasion than mere threats. At El Muerto
Island I saw various Blue-footed Boobies with crippled legs which I attributed
at first to injuries received from fishes, of which several predacious and large-
mouthed sorts are known in the surrounding waters. The lightkeeper assured
us, however, that they had been lacerated by Man-o'-war Birds. In view of the
testimony of Gifford (1913, 36) of a Swallow-tailed Gull which had its leg
dislocated by the marauders at the Galapagos, I think there can be no doubt
about the source of the boobies’ injuries. Friedmann (1927, 148) observed a
Man-o'-war Bird rob as active and aggressive a species as the Kelp Gull. Watson
(1908, 312) states that they frequently despoil other members of their own kind,
and he has seen them swoop down over the Sooty Tern colonies at Dry Tortugas,
causing a terrible commotion but, oddly enough, he learned of no case in which
they had attempted to rob the terns of their insignificant small fry, or to harm
the young in their nests. Neither did he ever observe the Sooty Tern attacking
Man-o’-war Birds, although the noddies frequently do.
The conditioned tameness of the Man-o’-war Birds during their breeding
934 OCEANIC BIRDS OF SOUTH AMERICA
season is replaced by shyness, or at least by a cautious indifference, at other
times of year. This, however, is readily modified if their feeding associations
bring them into close contact with human beings who carry no threat of harm.
Feilden (1889, 501) tells how the flying-fish catchers from Barbados become
surrounded by great flocks of Man-o’-war Birds, boobies, and Audubon’s Shear-
waters on the fishing grounds an hour's sail from the island. Off the ports of
northern Peru, it is customary to begin to clean the day’s catch as soon as the
homeward trip is begun. Therefore the wakes of the Indian fishing-boats become
filled with scrambling Man-o’-war Birds, which swoop up to the very stern to
seize fish-guts at the surface of the water or even to snatch them out of the air.
I suspect that the presence of a fishing encampment at Lobos de Tierra is what
tempts the birds down to that island from Sechura Bay. The Man-o'-war Birds
become equally accustomed to frequenting such spots as slaughterhouses on the
seacoast or on the banks of tropical rivers. At the water front of Guayaquil, a
city far upstream from the ocean, there is an abattoir so situated that part of the
offal falls on the bank and part into the stream, the proportions depending upon
the state of the tide. Here one can watch a completely amicable division of
spoils between the Man-o'-war Birds and the Black Vultures, for the latter
ignore all the tidbits afloat as completely as the Man-o’-war Birds disregard
whatever drops ashore. Elsewhere on the coast of Ecuador I have tossed refuse
from the bird-skinning table onto the sand and into the water, and have ob-
served again the manner in which these two species of scavengers divide the
world into shares. Such observations incline me to doubt the often repeated
story that Man-o’-war Birds pick up newly hatched sea turtles while they are
still on the beach on their way toward the ocean. On the other hand, if they
can gather sticks from the ground, why not turtles? Small examples of the
latter have frequently been found in Man-o'-war Bird stomachs, but so have
squids and other organisms which they perhaps never catch themselves but
frequently filch from the boobies.
Despite what I have said about the acquired confidence of the Man-o'-war
Birds, I believe that, except during the nesting period, they always retain cer-
tain susceptibilities not shared by most members of their order. Boobies,
pelicans, and cormorants on the mud flats of the Gulf of Guayaquil, or the rocks
of Point Santa Elena, were usually left unmoved by the report of my gun, even
though it had been aimed with fatal effect at one of their own number. The
Man-o’-war Birds showed no such stolidity, for a single shot was always enough
to cause them to leave an island or any other locality, and to sail away to a
great distance. Neither do I believe that they were accustomed to being shot
at, or that they had acquired any repellent associations with the sound of a gun.
In this connection it should be mentioned that Man-o'-war Birds are capable
of being easily tamed after capture, even though, as Allen (1905, 120) states,
their tempers are never to be trusted. He found in the Bahamas that birds which
had been deprived of their liberty for a short time, and had been fed with fish,
seemed to be quite content to sit upon a perch and wait for meals to be handed
or tossed to them. In fact, it became difficult to make them fly away unless
CARIBBEAN MAN-O'’-WAR BIRD 935,
they were actually thrown into the air. Such ready adaptability to a new réle
explains why the Pacific man-o'-war birds could be used as ‘‘carrier pigeons”’
by the Polynesians. Among the Samoan Islands and elsewhere it was customary
to erect perches for the man-o’-war birds outside human dwellings, and to
accustom the birds to being fed as they sat upon them. When their subsequent
foraging excursions would lead them toother islands roundabout, the birds would
drop down to be fed upon similar perches and thus, after the Christianization of
Samoa, the white and native pastors found an ocean postal service ready for
their use, just as the primitive people had formerly transmitted small objects,
such as shell fishhooks. Buller (1905, 50), quoting Turner, speaks of the carry-
ing of a note between two islands about 100 kilometers apart. The message
had been placed in a reed cylinder and attached to the wing of a frigate-bird
on a Friday. It was delivered on the subsequent Sunday afternoon. While the
message-carriers were presumably of the species minor, rather than magnificens,
there is every reason to think that the latter would be amenable to the same
purpose.
According to many accounts, Man-o'-war Birds of all sorts become extraor-
dinarily slumberous, or almost stupefied, at night, so that their capture at the
roosts is a simple matter even during the non-breeding season. They usually
return to their roosting trees some time before sunset but, instead of perching
at once, they sail slowly and magnificently about overhead until just before
dusk. Du Tertre (1667, 2, 269) speaks of an Ile des Frégates off Guadeloupe in
the Lesser Antilles, where great numbers of these birds were accustomed to
spend the night. Several times each year great hunts were organized by the
French colonists and negroes, and in one of these Pére du Tertre took part. The
birds were surprised among the branches where they could easily be caught,
notwithstanding that many of them disgorged good-sized fish as though they
were about to take flight. Within the space of two hours du Tertre himself
killed more than a hundred, but he gives no clue to the total extent of the
slaughter on this raid. Man-o’-war Birds were valued for their fat, which was
regarded as a sovereign remedy for rheumatic troubles and, as de Rochefort
(1658, 148) adds, for paralysis and dropsy!
Despite the eagerness with which Man-o’-war Birds rob each other of nest
material, as previously described, the structure they produce is hardly an ad-
mirable one for the safety and comfort of the single offspring. Beck states that
when the incubating Man-o'-war Birds take flight from the nest, they sometimes
roll the egg off with themselves. An island in Fonseca Bay, on the Pacific
coast of Honduras, was formerly a favorite Man-o’-war Bird center and here,
on New Year's Day, Taylor (1859, 150) found nests with eggs on nearly every
tree and bush, high and low, but hardly any was composed of more twigs than
a ring-dove would have used. In some cases one could look up through the
slight platform and see the egg from beneath. After the hatching of the egg,
such scanty platforms tend to become more firmly matted together by the drop-
pings of the chick. Todd (1916, 174), who visited a colony at the Isle of Pines,
speaks of how tenaciously young Man-o’-war Birds cling to their frail nests.
936 OCEANIC BIRDS OF SOUTH AMERICA
The trait has no doubt been enhanced by selection, for the alternatives to sitting
tight might be either to drop into the jaws of waiting crocodiles, or to be hanged
by the neck in the crotches of twigs. Salvin (1864, 375) thus describes a colony
in the nursery stage on an island off Belize, British Honduras, during April:
It was a curious sight, on thrusting one’s head out of the top of a tree, to watch the inhabitants
around. Three-fourths of the nests had young birds in them, of various ages: the more advanced
were commencing to shoot their scapular feathers; others, younger, looked like puff-balls of pure
white; while those which had just escaped from the shell were lying helplessly, as young birds do,
on the frail structure of sticks composing their nests. So slight were these, that the young in their
earliest infancy must have a perilous time of it. The youngest were guarded by one of the parent-
birds, which balanced itself on the edge of the nest. From the unhatched eggs the birds could
hardly be prevailed upon to stir. I have several times noticed this reluctance on the part of birds
building open nests to leave their eggs exposed to the direct rays of the tropical sun, whereas on
cloudy days the same solicitude was not exhibited.
Chapman (1908, 148) has studied a nesting colony of between two and three
hundred pairs at Cay Verde in the Bahamas. During April most nests here
contained young about half-grown, but there were still some fresh eggs, and a
few fledglings were already flying. The Man-o'-war Birds’ day, like that of the
boobies, began early and by 5.30 a.m. they were soaring about over the rookery.
At the end of the day, however, they settled to rest while it was yet light,
considerably before the retiring time of the boobies. At this season the gular
pouches of most of the males had faded from carmine to orange as a sign that
courtship, which marks the physiological peak in the life of the bird, had
passed. The newly hatched, naked young were closely brooded, not being left
alone or exposed to the sun until they had become covered with white down.
As the wing feathers of young Man-o'-war Birds sprout through the down,
the nestlings assume attitudes of extreme dejection, with the wings drooping,
doubtless from the weight of blood in the turgid quill shafts. Sometimes the
chicks lie with their heads hanging over the rim of the nest. They look much
like young pelicans, and utter squealing, chirping calls, besides rattling their
bills, all these actions likewise being reminiscent of pelicans at the same stage.
The adults are almost voiceless except for the gurgling vocalization produced
during courtship. At other times of year their sound-making is limited to a
clattering of the beak, Gosse (1847, 422) refers to a reiterated ‘‘chuck-chuck”’
coming from the Man-o'-war Birds as they are about to alight, but it is not
certain whether this is a vocal note, or what might be called an instrumental
sound, produced by the beak or the wings.
Despite the fact that the Man-o'-war Bird is a notorious highwayman, it
seems probable that the bulk of its food is captured by its own direct efforts.
The birds are certainly capable of catching extraordinarily active fishes, such
as the halfbeaks that slither along the surface of the water (Finsch, 1900, 446),
and flying fish. Lowe (1911, 213) watched one pursue, overtake, and seize a
flying fish in the air while half a gale of wind was blowing. According to my
own observations, the birds make a better job of capturing a lively animal
than of picking up a dead one, and there may be much truth in the statement of
Green (1887, 41), who was a very critical observer, that Man-o'-war Birds do
CARIBBEAN MAN-O’-WAR BIRD 937
most of their own fishing when the wind is high and the ocean turbulent,
reserving the booby-plundering game for calm weather. Most of the fish found
in their stomachs are of relatively large sorts. Hallinan (1924, 307) took an
example 35 centimeters long from a female shot at Panama. At the Dry Tortu-
gas, Watson found that local Man-o’-war Birds had eaten flying fish, herring,
and mullet, but none of the small fry upon which the terns feed. The Man-o’-
war Birds seem compelled to capture their food in a spectacular manner, often
plunging toward the sea from a great height, striking downward with the
beak, making a sound like the hiss of an arrow shot into the water (Robinson
and Richmond, 1895, 653), and then, without wetting feathers or feet, rising
and dexterously tossing up the prey before swallowing it. They are not known
to dive, and Gould (1841, 146) states that if any floating object sinks even a
short distance beneath the surface it is lost. Banks (in Hooker, 1896, 330)
describes Man-o’-war Birds “‘stooping at albecores so large that twenty times
their strength could not have lifted them.’’ In this case, however, the prey
pursued by the large fish was doubtless the real magnet that had drawn the
Man-o'-war Birds. I, too, have seen them following foraging schools of large
mackerels and carangids, and Scouler (1826, 199) long ago remarked that the
Man-o’-war Bird seems to be in alliance with the bonito for maintaining a
perpetual warfare against the flying fish.
In places where fresh-water ponds are accessible, the Man-o'-war Birds visit
them at times. At Little Abaco, in the Bahamas, Bonhote (1903, 312) saw
small bands come during March mornings to splash against the water of a pond
like swallows, never settling but rising again and going off to sea within a few
minutes. Noble (1916, 364) reports similar behavior at Guadeloupe. In the
crater-lake called El Junco, at an altitude of 800 meters or more on Chatham
Island of the Galapagos, Man-o'-war Birds have likewise been observed to
strike and splash against the surface. There can be little doubt that on such
occasions they drink fresh water, though many members of the species must go
through their lives with no opportunity to do so.
RIDGWAY’S MAN-O’-WAR BIRD
Fregata minor ridgwayi
Fregata minor ridgwayi Mathews, 1914, Austr. Avian Rec., 2, p. 120 (Culpepper Island, Galapagos).
Names: Listed in all the older writings under the specific name aquila.
Characters: Sexes dimorphic in color pattern, but the brown alar band present in both. Culmen
somewhat flattened, resembling the condition in aquéla rather than that in magnificens. Ventral
surface in the male duller than in either of these species.
Adult male: General plumage black, distinctly brownish on the entire ventral surface, and
with a broad radial alar bar of grayish brown feathers which includes the innermost secondaries
as well as the median coverts; the feathers from forehead to back are lanceolate and have a high
degree of metallic iridescence, which is chiefly bottle-green and blue on the head, and green and
bronzy purple on the back. Iris brown; bill leaden or horny gray; orbital ring black; gular sac red
during the breeding season; legs and feet red or flesh color.
Adult female: Very similar to the female of Fregata magnificens, but with the throat and fore
neck whitish or ashy instead of blackish. Orbital ring red.
938 OCEANIC BIRDS OF SOUTH AMERICA
I have measured no specimens of the Galapagos race of Fregata minor, and the figures of Gifford
(1913, 104) are intermingled with those of another species. Its size, however, seems to be not very
different from that of the next subspecies, Fregata minor nicolli. The distinctive characters have not
been adequately pointed out.
The juvenal plumage resembles that of magntficens, but the white head and breast are more or
less heavily tinged with rufous. The egg measurements recorded by Gifford include eggs of mag-
nificens, so that it is impossible to discriminate.
Distribution: Confined, so far as known, to the Galapagos Archipelago, and recorded speci-
fically from Culpepper, Wenman, Tower, and Hood Islands. Once taken near Clipperton Island
(Swarth, 1931, 40).
Only at the Galapagos Islands do the ranges of the species minor and magni-
ficens overlap. Gifford did not discriminate between the two in his important
account, but Swarth has shown that many of his data can be properly allocated
from the context. Gifford’s photographs made at Hood Island show the
present species.
It is only fair to say that the distinguishing characteristics between a Gala-
pagos race of minor and those in other parts of the world have never yet been
satisfactorily pointed out, but I am here using the subspecific name ridgwayi as
a matter of convenience.
At Hood Island the naturalists of the California Academy Expedition found
Ridgway’s Man-o’-war Birds nesting, remarkably close to the ground, on the
tops of small clumps of Sesuvium. The nests were made of dried stems of the
same plant piled on top of the green vegetation, and forming just enough of
a platform to provide a spring-off. Mating, copulation on the nest, and eggs
or young chicks were observed during February, September, and October, so
it is probable that breeding is practically continuous. This is further indicated
by the fact that one male with a bright red distended pouch was seen on the
nesting ground in June, when the throats of all others had turned dull. Newly
fledged flying young observed in June were believed to have hatched from eggs
laid in February, which gives a clue to the combined periods of incubation and
nestling life. Males and females were indiscriminately sitting on nests during
both February and September, the males often uttering the chuckling call.
They were silent when approached, but often vigorously defended their homes
with their bills. One downy young Man-o'-war Bird at Hood Island was being
cared for by a Masked Booby (Sula dactylatra).
Gifford lists 24 islands and islets of the Galapagos inhabited by man-o’-war
birds. It is probable, as Swarth remarks, that both resident species are generally
distributed, with segregation of the respective nesting grounds.
SOUTH TRINIDAD MAN-O’-WAR BIRD
Fregata minor nicolli
Fregata minor nicolli Mathews, 1914, Austr. Avian Rec., 2, p. 118 (South Trinidad Island).
Names: Formerly listed in several accounts under the name aquila.
Characters: Similar to the preceding subspecies, and to the typical form of minor. The sub-
specific peculiarities of the South Trinidad race have never adequately been pointed out. Mathews
and Iredale (1921, 60) state that it is characterized by a large bill and “'a very broad pale wing band.”’
SOUTH TRINIDAD MAN-O'-WAR BIRD 939
Bills of adults of both sexes are generally horn-color, but very rosy on the latericorn and the
sides of the mandible. Males have scarlet pouches (when courting), and bright red legs and feet.
In females the bare orbital ring is red and the feet are apparently pink.
1 adult male, South Trinidad: wing, 575; tail, 425; exposed culmen, 115.2; width of maxilla
at base, 33.8 mm. The length in the flesh of this example was 95 cm., its wing-span 206 cm.
4 females, South Trinidad: wing, 595-627 (605); tail, 400-426 (414); exposed culmen, 116.5-125
(120); width of maxilla at base, 34-36.5 (35); depth of closed bill at mid-point, 16.520 (18) mm.
Among these examples the length was 99-103 (100), and the wing-span 206-220 (211) cm.
Youthful stages differ from those of Fregata magnificens chiefly in that the white areas are more
or less heavily overlaid with the rufous coloration which is especially characteristic of the species
minor and ariel.
Distribution: Confined, so far as known, to South Trinidad Island and the neighboring Martin
Vas Rocks.
Chiefly upon a basis of geographic probability, I make use of the subspecific
name nicolli, leaving to future taxonomic work the task of properly distinguish-
ing the South Trinidad Man-o'-war Bird from other forms of the species minor.
The American Museum possesses six specimens of this race which were
collected at South Trinidad by members of the Cleveland Museum Expedition
during December, 1924, and January, 1925. At that time the birds were found
nesting at Dom Pedro Segundo Islet of the Martin Vas group, as well as at
South Trinidad (Simmons, 1927, 27). Dom Pedro supports only growths of
grass and sedge, rather than shrubbery, and the presence of the nesting Man-o’-
war Birds is another of many indications that representatives of the species
minor are less dependent upon trees and bushes than are those of the species
magnificens.
Both this Man-o’-war Bird and the lesser one of South Trinidad are probably
extremely sedentary. On the ‘Terra Nova’ expedition, in July, 1910, Dr. Wilson
found that examples of both the resident species followed the vessel only about
18 kilometers from the island (Lowe and Kinnear, 1930, 187). I have already
shown that the form from the Brazilian coast described by Ribeiro as Fregata
minor januaria belongs, in reality, to magnificens.
Fregata minor nicolli, and also the Lesser Man-o'-war Bird of South Trinidad,
have presumably entered our field from the southeast. Lowe and Kinnear are
incorrect in believing that there is a difficult ‘‘climatic barrier in the shape of
the cold roaring forties’’ between the Indian Ocean and the South Atlantic.
The southern tip of Africa falls just short of the 35th parallel of south latitude,
besides which, as I have already shown, the Sub-Tropical Convergence takes
a definite southward loop in that region.
LESSER MAN-O’-WAR BIRD
Fregata ariel trinitatis
Fregata ariel trinitatis Ribeiro, 1919, Arch. Mus. Nac. Rio de Janeiro, 22, p. 192 (South Trinidad Island).
Names: A synonym is wilsoni, which has been used both specifically and subspecifically.
Characters: The species is the smallest of the genus. The subspecific characters, which may
distinguish the South Trinidad bird from races of the Indian and Pacific Oceans, have not been
adequately pointed out. The male of ariel is marked by a conspicuous white patch on either side,
under the wing.
940 OCEANIC BIRDS OF SOUTH AMERICA
Adult male: Generally black, the ventral surface, which has a brownish cast, broken by a large
white patch on either side of the abdomen; lanceolate feathers of crown, scapulars, and inter-
scapular region glossed with green, blue, and purplish iridescence; considerable very dark bluish
and bronzy gloss is also present on all the coverts of the wing. Iris brown; bill gray or blackish
horn-color; gular sac red, at least during courtship season; bare eyelids, legs and feet, black.
Adult female: Almost identical in appearance with the female of Fregata minor but with a red-
dish or chestnut collar crossing the lower hind neck, separating the mottled brownish pileum from
the dark back; throat dirty white; breast and sides white; belly black. Eyelid, gular sac, and
feet fleshy red.
1 adult male, South Trinidad: wing, 537; tail, 268; exposed culmen, 81; width of maxilla at
base, 26; depth of closed bill at mid-point, 12.5 mm. The length in the flesh was 74, the wing-span
176 cm.
1 adult female, South Trinidad: wing, 558; tail, 326; exposed culmen, 93.3; width of maxilla
at base, 27.5; depth of closed bill at mid-point, 13.3. The length in the flesh was 82, the wing-
span 190 cm.
An immature example of unknown sex, which I examined at South Trinidad on April 8, 1913,
had the head and neck white, with a chestnut stripe running from the mentum down the front of
the neck to the upper breast; back, wings, breast, flanks, tail, upper and under tail coverts iri-
descent greenish black, the feathers of the scapular and interscapular region edged and tipped with
brown; the usual scale-like row of brown feathers, with darker shafts and whitish edges, extending
along the wing from wrist to elbow; belly white; feet flesh color; skin of throat blue.
In connection with the last, it is of interest that Gifford (1913, 102) notes that the skin over
the entire body of the downy young of Fregata minor at the Galapagos is china-blue in color, this
including also the feet and the bill.
I have seen neither chicks nor eggs of the South Trinidad Lesser Man-o’-war Bird.
Distribution: Confined, so far as known, to South Trinidad and Martin Vas.
The first example of the Lesser Frigate-bird, which is chiefly a species of the
Pacific and Indian Oceans, was reported from South Trinidad by Sharpe (1904,
214). The race trinitatis was subsequently described by Ribeiro, but its relation-
ship with those inhabiting other parts of the world has not yet been satis-
factorily pointed out. Simmons (1927, 27) observed this and the larger Man-o’-
war Bird flying about the Martin Vas Islets at the time of his visit in December.
He subsequently found the lesser species breeding at South Trinidad, the egg
being laid and the chick reared on the fallen trunks of Brazilwood (Caesalpinia)
trees, with a scanty nest construction in the form of a handful of twigs.
Our only specimens are a pair collected by the Cleveland Museum party at
the anchorage of the ‘Blossom’ off South Trinidad. At the time of my own brief
visit to the island, in April, I saw many immature examples over the surrounding
waters, and circling about some of the lofty spires, such as the Ninepin. One
was caught on a fishhook from the brig ‘Daisy,’ but the captain retained the
skin, which I have described above.
I saw a small troop of the Lesser Man-o’-war Birds fishing for themselves.
Half a dozen of them hovered in a row over a school of small surface fish,
facing in a direction opposite to that in which the fish were moving. While
the birds poised close over the water, they beat their wings slowly. Then at
the right moment they would strike downward, swinging their long bills like
scimitars back beneath their bodies, the hooked tip each time seizing a fish
from the rear. Every bird seemed to catch three or four a minute, and yet to
make no commotion among the moving school of its victims.
THE ANSERIFORMES 941
THE ANSERIFORMES
THE GEESE AND DUCKS
FAMILY ANATIDAE
Ducks, geese, and swans make up a cosmopolitan group of birds. The South
American representatives that come within the scope of this book are, however,
so few that a general account of the family would be out of place.
In Part I frequent reference has been made to the Black-necked Swan, to
several of the geese of the peculiar genus Chloéphaga, and to a variety of con-
tinental ducks which regularly reach salt water toward the southerly extremity
of South America. Many of the distinctive species and genera are of Andean
range in more northerly latitudes, illustrating the principle that birds from
probable sub-antarctic centers of dispersal have found a favorable environment
at higher latitudes in the direction of the tropics.
Most of the geese of the genus Chloéphaga are grassland fowl, to be associated
with fresh water, but the Kelp Goose is a species of the foreshore, and it feeds
exclusively upon marine organisms.
In South America there are no true ‘‘sea ducks’’ corresponding with the
many northern-hemisphere species of that category. The closest approach to
such is offered by the three extraordinary species of steamer ducks (Tachyeres),
which are, in a sense, analogues of the northern eiders.
The widely distributed pintail division of the genus Anas, comprising the
ducks often grouped under the generic name Dafila, has an isolated representa-
tive at South Georgia, and another at the antarctic island of Kerguelen in the
southern Indian Ocean. The South Georgian ‘‘Teal’’ is, indeed, a diminutive
replica of the Brown Pintail (Anas spinicauda). The habitat of the South
Georgian species lies directly to leeward of Tierra del Fuego, in the belt of
strong westerly winds, and its origin presents no special problem except that
regarding the age of the endemic, insular form.
The males of no South American duck have an eclipse plumage, which is so
characteristic among northern-hemisphere species.
Relatively little is yet known about the migration of South American Ana-
tidae. Certain Patagonian species move northward at the approach of winter,
but migratory flights are at least more sporadic than in holarctic areas. During
periods of drought the exodus may be no less irregular as to direction than as to
season. Reference has already been made to movements from the continent to the
Falkland Islands (p. 207), and to the flight in numbers of such species as Anas
Spinicauda and Oxyura vittata across Drake Strait to the South Shetlands (p. 219).
Many southern South American Anatidae, including such diverse types as the
swan, the native geese, and the steamer ducks, show a curious functional resem-
blance in the particular form of the extremely hard, hooked, knife-edged nails at
the tips of both mandibles. Among certain species this structure serves admira-
bly for snipping limpets and other univalve mollusks from the rocks, although
the character is shared equally by related fresh-water and upland forms.
942 OCEANIC BIRDS OF SOUTH AMERICA
KELP GOOSE
Chloéphaga hybrida hybrida
Anas Hybrida Molina, 1782, Sagg. Stor. Nat. Chili, p. 241 (Chiloé Island).
Names: Antarctic Goose; ‘‘Cagiie’’ or ‘‘Caranca’’ in Chile. Synonyms of the specific name
include antarctica and ganta.
Characters: The only species of the genus in which the adult male is of wholly white plumage,
the female black with white bars and other white markings.
Adult male: Plumage entirely white. Iris brown; bill black with an elongate flesh-colored
spot on the culmen above the nostrils; legs and feet citron-yellow.
Adult female: General color brownish black, heavily barred with white on the sides and
breast, the lower back, rump, tail, and abdomen white; crown and nape brown (between drab and
hair-brown); forehead, face, throat, and neck blackish brown, the feathers finely and obscurely
margined with buffy white, a color which in some cases prevails about the base of the bill; a white
circumorbital ring; breast, caudad to the abdomen, and sides of body, black, strongly barred with
white, each feather bearing from 4 to 12 alternating black and white bars, the terminal bar being
black; in fresh plumage these bars extend dorsally beyond the sides of the breast and are faintly
indicated as marginal lines across the upper back; upper back, scapulars, and tertials rich brown
(close to clove-brown or fuscous); the primaries similar but darker; lesser and median wing coverts,
margin of wing, secondaries, and under coverts white, producing large carpal and manal spots in
the wing when spread, the greater wing coverts metallic green on their outer webs, forming a
pronounced speculum; individually these feathers are tipped with black and narrowly margined
with white. Iris brown; bill flesh color; legs and feet yellow.
12 males: wing, 363-385 (370.5); tail, 127.5-139 (131.5); exposed culmen, 35.5-38.3 (36.7);
width of maxilla, 18-20 (19.1); tarsus, 66.3-71.1 (69.4); middle toe and claw, 76-83.2 (81.2) mm.
16 females: wing, 334-359 (348.7); tail, 126.5-137.5 (130.2); exposed culmen, 34.6-38.6
(36); width of maxilla, 16.3-19.4 (17.9); tarsus, 61.3-66.1 (63.7); middle toe and claw, 70.4-78.8
(75.5) mm.
Adults show little seasonal change in plumage save that caused by wear and replacement.
Youthful females have only indistinct crown-patches, and the barring of the belly extends
caudad almost to the crissum. In the center of the belly, furthermore, it breaks down into an
indistinct mottling. The green speculum formed on the wing of adult females by the secondary
coverts is entirely lacking in young birds, the corresponding region being plain brownish black.
Moreover, the upper tail coverts are dark instead of white. Two such young examples were taken
at Bertrand Island and in Beagle Channel, on April 22 and May 4, 1915, respectively.
The sequence of plumages in young males is beautifully illustrated by a series of specimens,
as follows:
Gable Island, May 2. Still largely in plumage resembling that of the female, except that the
head is more whitish, as always, and there is, of course, no green speculum in the wing. A few
white feathers have come into the black back, but the flanks and breasts are barred, and the belly
sparingly so.
Beagle Channel, July 29. Prevailingly white except for the wings. The remaining barring on
the body plumage is asymmetrical, being much more conspicuous on the right side and flank
than the lef.
Strait of Magellan, November 26. White, save for the wings and a few dark feathers on back
and breast.
London Island, January 18. White except for the primaries and a single two-barred feather
on the breast.
Bertrand Island, April 22. White, but with the primary row made up of mixed mottled and
pure white quills.
The foregoing 5 immature males, and many comparable birds, had small gonads, and were
recorded by Beck as non-breeders.
Downy young represented in the Brewster-Sanford Collection include birds not long out of the
egg, and goslings about twice as large. The smallest are 4 that appear to be of one brood, 2 of
EELP GOOSE 943
which are males and 2 females. These were taken at Stewart Island in December, 1914. Their
bills are black but white-tipped on both mandibles, and the egg-tooth is intact on 2 of them.
The legs and feet were blackish gray in life. The down is long and soft, whitish, but shot through
with a dirty, dusky color both above and below, the head being the whitest part. Looping around
the eye is a pronounced dark stripe, in contact with the upper eyelid and covering the forward
part of the lower lid as well, and then extending a short distance behind the eye. A brood of much
larger goslings is of almost identical appearance as regards plumage, except that the dusky brownish
areas are More conspicuous on the back. The bills, moreover, have lost their conspicuous whitish
tips, and the feet are brownish black. These are 2 males and 2 females taken at Caroline Island,
December 14 and 16, 1914. A third brood is represented by a single gosling of the same size as the
last, taken at Wollaston Island, January 5, 1915.
Eggs are said to be creamy white, closely resembling those of the Flightless Steamer Duck
(Tachyeres pteneres) but slightly smaller. This is confirmed by our specimens of eggs of the Falkland
Kelp Goose, described hereafter.
Distribution: From the vicinity of Corral, Chile, southward to the Strait of Magellan, the
southernmost Fuegian islands, and Staten Island.
The Kelp Goose is a robust, strictly coastal member of a curious South Ameri-
can genus, the species of which occupy various ranges between the highlands
of the southern Andes and the sea, and reaching to islands as remote as the Falk-
lands. In both plumage and structure the Kelp Goose is the most distinctive
member of the group, its very much larger feet and relatively shorter tarsus
being in themselves sufficient to separate it subgenerically from the other species
(Wetmore, 1926, 415).
The range of the Kelp Goose extends from a point on the Chilean coast near
Corral, or about latitude 40° S., southward through the archipelagoes to Cape
Horn and Staten Island. It is also common in the westerly part of the Strait of
Magellan, and apparently once bred as near to the Atlantic end as Elizabeth or
Isabel Island, which is just to westward of the Second Narrows. The Kelp
Goose is, however, a largely pedestrian bird of the intertidal zone and, like the
Flightless Steamer Duck, it avoids coasts subject to enormous daily variation
in the tidal level. For such reasons it is rare or absent along the eastern coast of
Tierra de] Fuego and the corresponding stretch of generally straight and cliffy
shore of Atlantic Patagonia.
The Kelp Goose has a number of peculiarities in addition to the very great
difference in the appearance of males and females, which reaches an extreme
of sexual dimorphism. It never goes far inland nor far from salt water, and yet,
on the other hand, as Coppinger (1884, 56) writes, it rarely wets its feet except
on the damp seaweed of the foreshore. Only after the young hatch do the
Kelp Geese take for a time to life afloat. At other periods of the year the birds
walk their own beats along rocky or shingly coasts, avoiding sandy stretches,
and browse upon a delicate green dulse which the Chileans call “‘luche.”’
Furthermore, the Kelp Geese are seldom to be seen in flocks as are other members
of their genus, and, except during the season of family parties, just before the
full-grown goslings separate from their parents, they are usually to be found
only in pairs, the exquisite white gander standing out like a spot of snow against
the dark Magellanic background. His mate, partly because of her obliterative
pattern and partly through the sheer contrasting glamour of the male, is likely
944 OCEANIC BIRDS OF SOUTH AMERICA
to be overlooked, even though she may be standing beside him. If the gander is
actually determined to be mounting guard in solitary state, or, like an ermine-
coated king in the midst of a court composed of gulls and cormorants, it is likely
that the goose is covering eggs in a hidden nest close by. Under such circum-
stances, as Coppinger remarks, her plumage assimilates so thoroughly with the
dark, wind-blown seaweed and the rank grass that she has no need to stir
until she is almost stepped upon.
Chiloé is the type locality of this species, and the western rocky coast of the
island probably marks the northern limit of the breeding range. At the
Guaitecas and Chonos Islands and, in fact, throughout the insular complex
stretching toward the Strait of Magellan, it is everywhere abundant on rocky
shores, as reported by Blaauw (1916, 480), Hellmayr (1932, 317), and others.
During the Brewster-Sanford Expedition, Beck first encountered Kelp Geese at
islets about 25 kilometers from Anctd, in northern Chiloé, on April 7, 1914.
The behavior of the birds impressed him then as gull-like rather than goose-like.
They kept to the windward shores of the islets, where surf was pounding heavily
on the rocks, and seemed very wary of a boat, usually flushing far out of gun
range. During the following month, at Cuellon in southern Chiloé, Beck met
pairs as well as family groups along the coasts which were here, too, rocky and
surf-beaten.
Subsequently, along broken and rugged shores of the channels leading toward
Cape Horn, Beck became more and more familiar with the Kelp Geese, found
their newly hatched young at Caroline, O’Brien, and Peyron Islands, during
December and January, and observed that the parent geese sometimes leave the
goslings in hiding on land while they swim to an adjacent stretch of rocks in
search of pasturage for their own needs. He learned, too, that when a brood of
the young geese is taken by surprise, the goslings invariably separate, each one
scurrying off at top speed in a different direction. In addition to the specimens
listed in the head matter, Beck collected others, which cover every season and
eight different months of the year, in Beagle Channel and at Caroline, London,
Timbales, King, and Bertrand Islands.
His notes upon the condition of the gonads show that the height of the
breeding season is reached during November, and that the moult of the wing
quills, which may make the Kelp Geese for a time quite flightless, is begun
soon after the eggs have hatched and while the whole family has taken together
to a swimming life. At Hermite Island, in December, Reynolds (1934, 84) saw
a score of Kelp Geese flap out on the water, apparently unable to fly. He took
them to be either yearlings, or non-breeders which had moulted exceptionally
early. Completion of the moult may require four months or even longer, though
it is hardly likely that the birds are ever completely flightless for that length of
time. Beck's specimens confirm the belief expressed by Hellmayr, upon the
basis of Conover’s observations, that geese of this species do not breed at the
end of their first year of life.
Reynolds (1934, 350; 1935, 83) reports that the Kelp Goose is the common
Chloéphaga of the Cape: Horn region, and refers to nests with eggs at Grévy,
EEL? GOOSE 945
Herschel, and Wollaston Islands. During December, 1932, he encountered
numerous families with three or more chicks, either small or half-grown. The
adults did not hesitate to lead their offspring out to sea into the immediate
proximity of sea-lions although, as Reynolds remarks, the birds are rarely seen
on the water at any other time of year. He adds the following account of a
probable battle between rival ganders, and its result.
While entering harbour at Deceit there was a distant beating of white wings on the water.
The scene was passed on the way to the anchorage, and a Kelp gander was noticed motionless and
decrepit-looking on the shore. In the water opposite to him was a second male (vanquished by the
first ?) on his back with his wings tangled in the kelp and his feet kicking in the air, but his head
held just above the water. In a few minutes the boat returned to the place to find a Giant Petrel
tearing at the mutilated remains of a sodden carcass.
Such battles are fought mainly with the large dull spur or tubercle present
on the wrist of both sexes. The nail of the bill also looks formidable, although
I have no evidence that it is used in conflict. It is shaped extraordinarily like
that of the steamer duck, and seems particularly well adapted for prying such
clinging creatures as limpets and chitons from the rocks. The evidence, however,
that the Kelp Geese feed on other than vegetable food is unconvincing. Blaauw
(1913, 144) succeeded in transporting a captive example over the Andes and
through the tropics to Holland by feeding it with dried luche, which he soaked
in water before the bird's meal, and by supplementing this with green cabbage
leaves. Since luche is also used as human food in Chile, it is somewhat surprising
that the Kelp Goose has almost universally been found to be practically inedible.
The Fuegian Indians apparently had no such prejudice because, according to
de Agostini (1924, 279), they were accustomed to catch Kelp Geese in snares
made of the sinews of the guanaco or of shreds of whalebone, and likewise of
conducting fire-lighting expeditions at night to the small roosting islets, where
they could beat down great numbers of the birds dazzled by the glare of their
torches.
FALKLAND KELP GOOSE
Chloéphaga hybrida malvinarum
Chloéphaga hybrida malvinarum Phillips, 1916, Auk, 33, p. 423 (Port Stephens, Falkland Islands).
Characters: “Similar to C. hybrida hybrida from Patagonia and the Straits of Magellan, but
larger, especially in length, depth and breadth of culmen. Pileum in the females, paler and more
grayish; drab to light drab (Ridgway, 1912), instead of cinnamon brown”’ (Phillips).
1 male: wing, 390; tail, 138.7; exposed culmen, 38.8; width of maxilla, 21.1; tarsus, 76; middle
toe and claw, 85.2 mm.
4 females: wing, 360-380 (368); tail, 132.5-135.7 (134.1); exposed culmen, 36-40.4 (38.7);
width of maxilla, 18.6-19.4 (19); tarsus, 67.3-70 (68.3); middle toe and claw, 77.1-80.9 (79) mm.
Four nearly fresh eggs taken at Bleaker Island, December 12, 1915, closely resemble steamer
duck eggs. They are creamy white, smooth, and slightly variable in form, two of them being
somewhat pointed at the smaller end. Measurements of the set are: 79.3 x 54.2, 80.2 x 55, 78.4 x
55.4, and 77.7 x 55.2 mm.
Distribution: The Falkland Islands.
The sealers and other early visitors to the Falkland Islands soon learned to
classify the several forms of peculiar native geese on gastronomic grounds. As
946 OCEANIC BIRDS OF SOUTH AMERICA
related by Clayton (1776, 104), the kinds were known as, (1) the Mountain
Goose, which feeds among the hills and is the best eating; (2) the Valley
Goose, which is fairly good eating, best and fattest between February and
April; and (3) the Sea Goose, which forages on the shore and is edible
only for starving men. In modern terminology these three birds are, respec-
tively, the Brent Goose (Chloéphaga rubidiceps), the Upland Goose (Chloé-
phaga picta), and the Falkland Kelp Goose, the last being the subject of
this biography.
When describing an endemic Falkland race of the Kelp Goose, Dr. Phillips
stressed the Jarger size of the bill in comparison with that of the typical form
of southern South America. The specimens collected by Mr. Beck show, how-
ever, that the superior size of Falkland birds is no less marked in the length of
the wing and of the leg and foot. During the course of the Brewster-Sanford
Expedition, Beck collected five specimens near Port Stanley and Port Louis, in
the months of November and January, and at Bleaker Island took the set of four
eggs referred to above, which were ina grass-built nest, well lined with feathers
and down, a few steps from the water's edge. Vallentin (1924, 315) says that
the set of eggs usually numbers from two to four, but Cobb (1934, 54) has found
that it may go to six.
Today the Kelp Goose is more abundant in the western part of the archipelago
than elsewhere. Vallentin, who has studied the species in West Falkland,
writes as follows:
When once paired, these birds are inseparable, and the snow-white gander is a most con-
spicuous object amid a landscape of greys and browns and can be easily distinguished at almost
any distance. The female is spotted and barred with black and white feathers, and therefore very
difficult to distinguish, even at close quarters. Often when out nesting, I have seen several of the
males a long distance away and have marked their positions, for they invariably move off on the
approach of a stranger. On reaching the spot where I first saw them, a search in circles radiating
from this centre would then be made, and many times I have often nearly stepped on the sitting
goose before seeing her. There is a very sheltered spot in the north-west corner of the West Falk-
lands called Whaler Bay, for in the old days it was the favourite resort for whalers and sealers,
driftwood, peat, and plenty of fresh water being easily procurable. At present it is even less dis-
turbed than before, no one except in quest of sheep ever visiting the spot; hence the birds are very
seldom, if ever, molested. Frequently while having my lunch there near the sea-shore quite a
number of these birds would gather round and amuse me with their quaint ways. By far the most
inquisitive was the goose, who would boldly walk up to within two or three yards of my seat,
and prance about, raising and lowering her head, and uttering soft notes of apparent self-satisfac-
tion the while. Soon the snow-white gander would come near, but he was at once driven off, and
then the antics were renewed. After a time, several birds of both sexes would come up, and then
a free fight always followed, the victorious pair remaining masters of the field.
From Cobb's no less entertaining than informing account I draw much of
the following matter, taking the liberty of intercalating a little text from other
sources.
The Falkland Kelp Goose is highly ornamental, but hardly useful in the
opinion of human beings whose thinking is closely connected with their
stomachs. Moreover, its eggs, even in the freshest state, come under the heading
of those suitable to give away. If an ill-disposed person wants to be nasty, he
FALKLAND KELP GOOSE 947
will introduce some Kelp Goose eggs among those of the Upland Goose, and
thus betray somebody into eating the former.
On the other hand, the Kelp Goose has no especially bad habits from man’s
supremely self-centered point of view. Its neighbor, the Upland Goose, eats
grass and therefore competes with sheep, so that in the Falklands a price has
been placed upon its head. The Kelp Goose harmlessly clings to its rocky shores,
and feeds upon a green seaweed known as Porphyra umbilicalis which abounds
in the intertidal zone. Contrary to statements frequently made in the literature,
it does not subsist upon mollusks and other neritic animals, but sticks almost
altogether to algae except in the autumn, when the fruits of the crowberry or
diddle-dee are ripe, at which time it wanders inland by pairs in search of this
terrestrial food (Vallentin). At all other seasons the Kelp Geese avoid not only
the dry Jand, but also the water! Rather than take refuge in swimming or flight,
they will run along the rocks in front of a man for a good distance. If a bird
that has been shot happens to fall into the water, its fluffy plumage quickly
becomes water-soaked in a manner that seems extraordinary for a member of its
family (Brooks, 1917, 152).
The flight of the Kelp Goose is clumsy. It appears ‘‘down by the stern,”’
and does not rise high. The principal use of the wings seems to be to carry the
birds to their nightly roosts on small tussocky islands, a short distance off the
coasts of the main bodies of land. At dusk the Kelp Geese fly to such refuges
from all directions, a custom which may well be a survival from the time when
so-called foxes abounded in the Falklands.
Before nesting commences there is a deal of courting and sorting out of undesirable partners.
The females seem to outnumber the males very considerably, so that the eligible ganders are
mobbed by perhaps seven or eight fascinating young geese, and, like human beings, find some
difficulty in selecting the right one. When she has been selected, she is given the difficult job of
driving off all the rejected from the gander, scolding as she rushes first at one and then at another
of the geese, which, being geese, appear still hopeful that something will turn up to give them a
chance (Cobb, 1934, 55).
Since the male of this species is not harried like the unfortunate Upland
gander, he behaves quite as though aware of his own conspicuousness, and of
the futility of attempting to hide. The only ordinary defensive reaction is a
tendency to move away from the nest when danger threatens, and even this
has been questioned by Cobb.
The Kelp Goose nests rather later than the other geese of the Falklands, few
eggs appearing until November. The female carefully covers the eggs with
feathers and grass when she leaves them. The goslings are hustled to the
nearest water as soon as they hatch out. Cobb states that the gander, in con-
trast with the valiant behavior of the male Upland Goose, takes no part in the
defense of the young when danger strikes.
Brooks writes that when the female becomes nervous, she utters a harsh
Uh-hih-uh-hih-uh-hih, with a rising inflection. The male's only call is a thin
and feeble Seep-seep.
948 OCEANIC BIRDS OF SOUTH AMERICA
SOUTH GEORGIAN TEAL
Anas georgica
Anas georgica Gmelin, 1789, Syst. Nat. 1, pt. 2, p. 516 (South Georgia Island).
Names: The duck of South Georgia has been described under the specific names antarctica and
xanthorhyncha, besides which it has been listed as eatoni, which properly belongs to the species of
Kerguelen Island.
Characters: A small duck of the pintail group, closely resembling Anas spinicauda of conti-
nental South America, from which it differs in its smaller size, the more dense spotting of the throat
and fore neck, and in having 16 instead of 14 rectrices.
Adult male: Crown rufous brown, streaked with black; sides of head buffy or grayish brown,
more finely speckled with blackish; neck still lighter, becoming gray or grayish white on the throat,
where there is a thick sprinkling of small guttate or sagittate brown central spots on the feathers;
dorsal surface prevailingly brown, the upper back buffy brown, the tertials mainly olive-brown,
but all the feathers with grayish or buffy margins; tertials with a central, more or less velvety,
black stripe, chiefly on the inner web; wing coverts hair-brown, with darker shaft streaks, the distal
row buffy white, succeeded on the secondaries by a velvety black speculum with a faint green
lustre, and again by the buffy white band marking the end of these quills; primaries hair-brown,
slightly darker on their outer webs and distally blackish; rectrices hair-brown, the central elongate
pair with rufous margins; chest more rufescent than back, each feather having a large subterminal
blackish brown spot surrounded by a lighter rufous brown margin; the feathers of the breast and
belly are similar, except that the margins are lighter, the center of the belly being almost white;
under wing coverts and axillaries hair-brown, the longer members with whitish tips and more or
less white sprinkling. Iris dark brown; culmen, nail, and distal borders of the maxilla black;
remainder of the tip of bill slaty blue; sides of maxilla Naples yellow, becoming greenish where it
blends with the blue tip; legs and feet olive-green mottled with sooty brown, the joints and webs
darker.
Adult female: Similar, but with a dark brown speculum showing no more than a distal sug-
gestion of velvety black; the band formed by the tips of the secondaries is likewise more buffy,
and the velvety black stripes on the tertials are less conspicuous. P
8 males: length (skins), 418-445 (432); wing, 211-222 (217); tail, 93-104 (100); exposed cul-
men, 32-36 (34); width of bill at base, 12.5-16 (14); tarsus, 35.5-39 (37); middle toe and claw,
45-51 (48) mm.
4 females: length, 390-412 (404); wing, 195-207 (201); tail, 85-93 (89); exposed culmen, 31-
34 (33); width of bill at base, 12-15 (13); tarsus, 35-36 (35.9); middle toe and claw, 46-49 (48) mm.
Immature birds generally resemble adults. In downy young the head, neck, sides of breast,
upper back, and a narrow collar around the neck are cinnamon-brown, the lower back and rump
darker, close to clove-brown; paired yellowish white spots, or a broken stripe, behind wings and
at side of rump; a faintly indicated post-ocular light mark; throat, breast, and belly dull yellowish
or dark olive-buff.
Eggs are five to a clutch, rounded-ovate, cream-colored, with a highly polished surface. Mea-
surements seem not to be on record.
Distribution: Endemic at South Georgia; formerly abundant along the northwestern coast
of the island.
This teal was among the birds noted by Captain James Cook, in January,
1775, on the occasion of the first recorded landing at South Georgia. Until
after the beginning of the present century it was probably abundant in all of
the great fiord-like valleys on the northwestern coast of the island. Von den
Steinen (1890, 219) and other members of the German Expedition at South
Georgia observed several flocks numbering about a hundred individuals at
Royal Bay, and later records indicate that such aggregations were not extraor-
dinary during the winter season, when the little ducks were accustomed to
SOUTAsGEORGIAN:) TEAL 949
leave the snow-covered tundra and meadow land and to congregate on the sea-
coast, particularly about the mouths of glacial streams. The reduction in
numbers is undoubtedly due to the fact that the teal has been persistently shot
for the pot since South Georgia has become a more or less permanent home of
whalemen. The birds are no longer numerous, and the latest writer (Matthews,
1929, 583) states that it is now unusual to find flocks of more than half a dozen
ducks on the beaches in winter. Fortunately, the configuration of the land at
South Georgia is of a character to prevent the complete extermination of the
teal, for the northern fiords to which the whaling stations are confined are
separated from adjacent fiords by almost impassable glaciers and ice-capped
ranges. Therefore the ducks might conceivably be wiped out in one valley and
yet be common just beyond the next ridge.
The South Georgian Teal is a pioneering member of a group of ducks in-
habiting the southern tip of the continental region, thirty degrees of longitude
directly to windward. Its closest relative is evidently the widely distributed
South American Brown Pintail (Anas spinicauda). In most of the earlier litera-
ture the pintail is listed under the generic name Dafila, while the South Georgian
Teal has usually been relegated to Nettion. The resemblance between these two
species is very striking, and the case furnishes an excellent example of close
taxonomic relationship which has been obscured by nomenclature. Considering
the similarity between these two ducks, it is somewhat surprising that the
South Georgian Teal has 16 rectrices whereas the Brown Pintail has only 14.
Usually, among the Anatidae as in other families, the larger species have the
greater number of tail feathers, but here the rule is reversed.
At the Bay of Isles, South Georgia, I found the teals fairly common in
December, 1912. They were most in evidence on grassy islets in the bay, and
were remarkably unsophisticated, allowing bands of sealers to walk right up
to them as they fished for amphipods in the kelp fields at low tide, or dabbled
in fresh-water pools that filled every hollow of the tussock-grown islands. The
tameness of the birds, despite long persecution, shows once more the genetic
rather than empirical nature of such traits in island species. Like some of my
predecessors in the field, I found that males outnumbered females. At any rate,
I had collected a considerable series of drakes before being able to find any of
the other sex. This may have been partly due, of course, to the fact that many
of the ducks were engaged at the time in incubation.
On December 20, 1912, I photographed a pair of teals feeding in a trickle of
water which ran through tall tussock grass from the melting edge of a glacier.
The birds were well hidden by the screen of grass, and I almost stumbled over
them before seeing them. They appeared quite unconcerned, however, and con-
tinued prodding about in the mud. When I had come within two steps of them,
they raised their heads and waddled farther off among the hummocks, from
where they peered out through drooping grass. All but the bright eyes and
yellow bills blended completely with the surroundings. Matthews has well
said that their pattern fits in so thoroughly with the environment that it is
sometimes only the movement of the conspicuous yellow bill that calls one’s
950 OCEANIC BIRDS OF SOUTH AMERICA
attention to their presence. Many observers have noted the birds’ preference to
lose themselves in the grass when they are approached, rather than to seek
safety in the air, and it is likely that before the arrival of men and guns at South
Georgia they used their wings only for relatively short and infrequent flights.
During the last few days of February, 1913, I found the teals common and
exceedingly tame on the eastern shore of Possession Bay, far back from the open
ocean and remote from a whaling station. Here they fed in the ponds and in the
wet runways between tussock hummocks. Many times pairs came whizzing
toward me down the wind, wheeling to face it just before they pitched on the
ground or water, sometimes within a few paces of me. I often startled parents
with their broods, and heard the sharp note of alarm as the ducklings scampered
to cover. Whenever a brood was threatened, the mothers exhibited very well
the series of reactions which are sometimes interpreted as resourceful or self-
sacrificing. The ever-present enemy was, of course, the skua and, when a teal
and her ducklings were surprised, the parent would beat the ground like a
maimed creature, in a manner which needs no description, while the downy
young disappeared like magic in the tussock grass. On one occasion I saw a
skua pounce down upon a female teal as she was fluttering lamely in front of
me, whereupon the duck sprang off the ground and easily outdistanced her
enemy. Twice, however, skuas seized and carried off in their bills teals which
one of the officers of the brig ‘Daisy’ had just shot.
Finding the ducklings proved a difficult matter. I have hunted on hands and
knees for half an hour without succeeding in locating even one of the silent,
invisible youngsters in the thick grass. Our ship’s fox terrier, however, was
more successful. On February 6, after the dog had been whistled back from
following a mother teal, it sniffed about the spot where the family had been
flushed and presently caught one tiny duckling. The latter had evidently
hatched only recently and was a brown, long-tailed, confident little bird. It
sat on my hand and preened itself, stroking its back with its bill and scratching
its head with a foot. It could also jump from considerable heights to the ground
without being injured.
On February 28, I finally discovered a teal’s nest on top of a tussock hum-
mock, close beside a pond and about 200 meters from the shore of Possession
Bay. It was covered by standing blades of dead grass, which completely arched
it over. The sitting duck peeped out when I approached, but did not leave until
I touched the pedestal of the hammock. The nest was lined with dry grass and
a very few feathers, and held five eggs which lay with their small ends together
in the deep bowl.
Five eggs or chicks seem to be the usual complement, though four eggs were
noted by members of the German Expedition (Pagenstecher, 1885, 13). Natural-
ists of the German party observed pairing of the teals on November 19, the first
eggs on December 8, and the first young on December 18. Probably most of the
young hatch during December and January, but late layings, such as I have
noted above, are likely to be forced through destruction of the first eggs by
skuas or perhaps by rats. Chicks in the down have been observed as late as
SOUTH GEORGIAN TEAL 951
March 15. The single nest I found had no definite lining of down, but Matthews
and others have observed an abundant supply which makes the interior of the
bowl look grayish white.
It would be simple to speculate, as I have once before (Murphy, 1916, 275),
concerning the selective advantage of the South Georgian Teal's small brood
in a region where climatic conditions are in some respects exceedingly severe.
Among many northern-hemisphere waterfowl, which lay a large number of
eggs, the downy young are particularly likely to fall a prey to such enemies as
predatory carnivores, fish, or turtles, whereas at South Georgia the chief danger
probably lies in the destruction of the eggs before hatching, either through
exposure or through discovery by the skua. The number of eggs produced by
species of birds under practically all environmental conditions is, however, so
variable, and subject to so many exceptions, that an adaptive significance is at
best uncertain.
The South Georgian Teal undoubtedly takes a good proportion of its food
from salt water, but the birds spend so much time dabbling in ponds and runnels
that I presume they must also find both animal and vegetal sustenance ashore
as well as in the bays. A number of observers have found that they are com-
monest along the beaches at low tide and most likely to remain in hiding over
the period of high water.
The call of the male is a shrill whistle, repeated several times and frequently
uttered in flight. The duck utters a soft quack, and a gurgling note which von
den Steinen likened to the bursting of large bubbles.
Tue STEAMER Ducks
The steamer ducks, which are confined to southern South America, have
been the subject of active controversy for an extraordinarily long period of time.
Since the early days of discovery in the Falkland Islands and the Magellanic
region it has been known that certain of these birds can fly well, while others
are capable only of racing along the surface of the water, employing the short
wings as “‘side-wheels.’’ It has been pointed out many times that individual
ducks ascertained to be only ‘‘steamers’’ are the larger and bulkier of the two
kinds, while the fliers have a more slender build and obviously longer wings.
At the same time, the general resemblance between the two is strong, and they
are known to occur in the same region, and sometimes in company. Further-
more, both types “‘steam,”’ though only one flies.
From such facts various inferences have been drawn. One group of workers
has held that the distinction between the two is solely a matter of age, all
steamer ducks passing through a youthful flying stage, after which they settle
down and wax fat. Even the discovery that the flying birds lay eggs and rear
young, and that they are quite capable of launching into flight from their nests,
has not sufficed to convince certain taxonomists and field ornithologists that
more than one species exists.
Another school of students has held that the ‘‘steaming’’ and the flying
952 OCEANIC BIRDS OF SOUTH AMERICA
ducks are two distinct species, the possibility of subspecific relationship being
eliminated because large parts of the breeding ranges of the two sorts are shared
in common. The opinion of the aborigines, and of sheepmen and other white
residents of Tierra del Fuego, supports the two-species hypothesis; the Indians,
indeed, have different names not only for the two kinds of adult ducks, but
even for their respective ducklings.
Still a third theory to explain the two kinds of steamer ducks is that of Chap-
man, which is given below in his own words.
The history of the long and bewildering disagreement is well summarized
in the exhaustive writings of Phillips (1925, 3, 287) and Lowe (1934, 471).
The former of these authors arrives at no final conclusion, although he believes
that the findings cannot all be explained on the basis of one natural species.
Lowe has fully satisfied himself that there are two distinct species of steamer
ducks, and he presents tabulated matter and figures to illustrate the thorough-
going differences between the adult ducks of the two kinds and between their
respective young. His color-plate alone, indeed, shows convincing distinctions
between ducklings of the two sorts.
Most ornithologists, after studying Lowe's text, would regard the problem
as solved, and yet as keen a naturalist as Lord William Percy (1934, 867), who
has a deep knowledge of the ducks of the world and who has closely observed
steamer ducks in the field, apparently remains unconvinced. The fact is, as I
shall demonstrate conclusively, that while Dr. Lowe has developed his thesis
correctly up to a certain point, he has not gone far enough; he has, to be sure,
pointed out two well-marked species of steamer ducks but has, on the other
hand, added to the current tangle by assuming that the flightless species of
Magellanic South America is the same as the flightless species of the Falklafd
Islands.
The obstacle to solution of the question proves to lie in the widely accepted
fallacy that the ultimate truth about these birds is to be learned only through
field observation. As a result of his extensive experience in Chile, Chapman
(1933, 362), for example, writes:
I venture to suggest that there is but one species of Quettro, that young in their first winter
always fly, that those individuals that nest on salt water, and hence on their feeding-grounds,
lose the power of flight when mature, while those that nest on fresh water and fly to their feeding-
grounds retain the power of flight at all ages. This is only a working hypothesis to be tested by
field studies and by weights and measurements of specimens of flying and flightless birds collected
throughout the year.
Now I acknowledge that provisional observation of the behavior of living
steamer ducks is the necessary basis for any sound conclusion. The fact that
certain specimens collected by Mr. Beck during the Brewster-Sanford Expedition
are marked “‘shot while flying over land’’ establishes, for instance, a standard
of comparison, the characteristics of which are to be balanced against those
of other ducks, with large bodies and short wings, which could not be made
to leave the surface of the water and which, in fact, were incapable of flight.
Beyond such fundamental data, however, the steamer duck problem is not a
THE STEAMER DUCKS 953
field problem at all, but a purely taxonomic problem. With two or three
specimens at his disposal, a systematist might reach any one of several conclu-
sions; with twenty specimens he might become hopelessly befuddled, par-
ticularly if only part of the common range were represented, and if there were
not enough examples to indicate the normal adult plumages of each sex. But
the study of a hundred specimens covering all ages, all seasons, both sexes, and
the entire range of the genus—continental and Falkland—serves to clear up
every doubt. The steamer ducks then fall into their respective categories and
prove to be no more puzzling, no less conventional, and to have no wider limits
of variation than any other closely related members of a single genus.
The material upon which I base such confident opinions comprises 106
specimens, of which 12 Falkland birds were kindly lent to me by the Museum
of Comparative Zodlogy. The remainder were collected by Beck at Chiloé
Island, at many localities in and around Tierra del Fuego, on the Atlantic coast of
Patagonia, and at the Falkland Islands. This large series of steamer ducks, when
arranged like with like, shows that there are three distinct forms, as follows:
1. A flightless bird inhabiting the Falkland Islands.
2. A different flightless bird inhabiting the continental region, that is, all
the Magellanic insular and coastal waterways from Chiloé to Cape Horn.
3. A flying bird inhabiting all parts of the combined ranges of the two flight-
less forms, both in continental and Fuegian waters and at the Falklands.
The series shows, further,
that each of these three forms
of steamer duck is readily iden-
tifiable at every age and in every
stage of plumage; there is not a
““‘doubtful’”’ specimen among the
hundred. Moreover, it is during
downy stages that each one of
the three is most distinct from
the other two; as the ducks ma- Fic. 73. Beaks of two species of Steamer Ducks, to
ture they come to have an in- __ illustrate particularly relative size and the form of the
creasing superficial resemblance, maxillary and mandibular ungues. The drawings
although they are still readily "ePresent mature males.
identifiable by mutually exclu- Left, Flying Steamer Duck (Tachyeres patachonicus);
ee features of pattern seetc tive right, Magellanic Flightless Steamer Duck (Tachyeres
: : F pteneres).
and proportion. Finally, the curi-
ous probability is brought out that the Flying Steamer Duck is in some respects
more closely akin to the flightless duck of the Falklands than the latter is to
the flightless duck of the continent! By kinship I mean, of course, general
resemblance; we know nothing about the genetic or blood relationship of the
three. In Beck's field notes I find several somewhat surprised yet canny refer-
ences to the fact that the adult flightless bird of the Falklands looks more like
the flying bird than it does like the mainland flightless bird.
The differences between the forms of steamer ducks are of such quality and
954 OCEANIC BIRDS OF SOUTH AMERICA
degree that they might be regarded as subspecific, but the geographic relation-
ships obviously make it necessary to grant each form specific rank. Fortunately,
they have all long since been described, and to avoid further confusion of ideas
I list herewith the three species chronologically, under English and technical
names, one or more of the latter being resurrected from the synonymy. It
should be noted that the earliest name of all, Anas cinerea Gmelin 1789, is not
available for any steamer duck, since that combination had previously been
applied to the Gadwall.
1. Falkland Flightless Steamer Duck.
Tachyeres brachypterus (Latham) 1790.
2. Flying Steamer Duck.
Tachyeres patachonicus (King) 1830.
3. Magellanic Flightless Steamer Duck.
Tachyeres pteneres (Forster) 1844.
Various ornithologists, including Blaauw (1917, 274), Bennett (1924, 280),
Phillips, and Lowe have tabulated data purporting to distinguish two species
of steamer ducks, the criteria including habitat, behavior, size, plumage, mor-
phological proportions, eggs, etc. Some of the characteristics are sound, some
have no significance, and some are confused because of the authors’ failure to
recognize three species instead of two. Phillips's color-plate, for instance,
illustrates all three species under a single name, including the downy young of
the flightless Falkland bird; Lowe mixes up the eggs of the two flightless species,
and uses the name brachypterus to apply to both the Falkland and the continental
flightless ducks. In the drawings by Mr. Jaques which accompany this text,
some of the diagnostic features show more clearly than they could be expressed
in words. Further details are brought out in the descriptions under the three
specific headings. The following constant differences, referring to all three
species at various stages of growth, are worthy of special note.
Eggs: The eggs of the three steamer ducks look much alike but exhibit a
size difference which corresponds with that of the three species of birds. Vallen-
tin’s (1924, 322) opinion that the eggs of the flying and Falkland flightless ducks
can readily be separated if they become mixed is not to be relied upon, but
average measurements reveal a size sequence as follows:
pteneres brachy pterus patachonicus
11 eggs, 84.7 x 57.3 10 eggs, 82.1 x 56.6 29 eggs, 76.4 x 52 mm.
Downy young: Newly hatched ducklings are more distinctive in appearance
than are birds at any later stage. The diagnostic characters are as follows:
T. pteneres (continental flightless species): Dorsal color, bister; no supra-
orbital stripe; one post-ocular and one post-auricular white spot; bill, slaty,
with the nails of both maxilla and mandible pronounced and black.
T. brachypterus (Falkland flightless species): Buffy or olive-brown dorsally,
but with a broad grayish white yoke across the scapular region; a continuous
supra-orbital and post-auricular white stripe; bill substantially as in the pre-
ceding species.
THE STEAMER DUCKS 955
T. patachonicus (flying species): Dorsal color, earthy brown; a broad, white,
diffuse stripe running through the eye and looping behind the cheeks; bill,
bluish slate-color, of smaller size than in the preceding two species, and with
the maxillary unguis inconspicuous and of a horny color, the mandibular unguis
being barely discernible.
In connection with these diagnoses of newly hatched steamer ducks, Fig. 74
should be compared with plate 11 and text-figure 9 of Lowe's paper.
Adults: Plumage characters of
the full-grown ducks are somewhat
difficult to summarize because of the
many similar phases exhibited by
both sexes of the three species be-
fore the birds attain maturity. De-
tailed descriptions precede the sev-
eral biographies. A unique character
of T. brachypterus is the more or less
distinct ring of glossy golden feath-
ers around the neck. It is usually
evident in females to a greater extent
than in males, but no old Falkland
birds seem to be without a trace of it.
The difference between the Fly-
ing and the continental Flightless
Steamer Duck is particularly pro-
nounced in the form of the primary
quills and the color pattern of the
secondaries, the latter being the
feathers which carry the large white
speculum of the wing. Not only the
length, but also the breadth, of the
primaries are from a quarter to a
third greater in patachonicus than in
pteneres. In both species the outer- Py
most One or two secondaries have a Fic. 74. Pattern and relative pigmentation of
slight and variable dark subterminal the nestling down in two species of Flightless
spotting. If we disregard this, and Steamer Ducks.
count the secondaries inward, we Upper, Tachyeres brachypterus (Mus. Comp.
: : Zool. 70522, Falkland Islands); lower, Tachyeres
find that in patachonicus the first a pteneres (Brewster-Sanford 5100, Amer. Mus. Nat.
eleven, or twelve quills are white, Hist, Beagle Channel).
the first dark marks appearing on
the inner web of the eleventh, twelfth, or thirteenth feather. In most instances
the next succeeding feather is entirely dark. In pteneres, only six, seven, or
eight secondaries from the outermost are white, the gray markings usually
beginning on the inner web of the eighth or ninth, succeeding quills after the
first spotted one being more or less dark on both webs or entirely dark.
956 OCEANIC BIRDS OF SOUTH AMERICA
Size, weight, and length of the wing and other appendages also seem to offer
constant and tangible means of distinguishing between all three species, al-
though I unfortunately lack adequate flesh measurements and weights for the
species brachypterus. Figures applying to the other two steamer ducks are as
follows:
pteneres | patachonicus
Renpthwingehettleshi wan. seuaer yea. sane 2h =: 836 10@ 704 mm.
O57, 149 655
Wilp-Spans Myog, s eee ee tare Chto 30 1075 107 1088
iter eh! 149 1025
It will be observed that the smaller species has much the longer expanse.
The size difference between these two is brought out still more strongly by the
respective bulks, for the heaviest male of the flying species falls considerably
short of the weight of the lightest female of the flightless species.
pteneres patachonicus
Weiphtseyrry faci, i tov dda: tens 20 5897 min. 5c 2892 grams
6180 max. 3175
6039 aver. 3073
42 3629 min. 69 2438
4763 max. 2835
4111 aver. 2616
The heaviest male among a number of Falkland flightless birds (T. brachyp-
terus), taken at a season when the ducks were not very fat, was found by
Brooks to weigh 4309 grams.
The size of the maxillary nail is very large in the continental flightless bird,
small in the flying duck, and intermediate in the Falkland flightless species.
Extreme and average measurements of the width of this structure in adult males
are as follows:
pteneres brachypterus patachonicus
139 15.4-18.5 (17.1) 7H 11.9-14.2 (13.3) 16@ 10.6-13 (11.7)
Finally, the ratio obtained by dividing the length of the wing into that of
the tarsus proves to be constant within narrow limits, and apparently diagnos-
tic. The averages for males of the three species are, pteneres, .261; brachypterus,
.237; patachonicus, .203.
Significant osteological differences between the species patachonicus and
“brachypterus’’ (= pteneres), including figures and illustrations which show
the relative lengths of humerus and sternum in the two, have been set forth
by Lowe
The evolutionary probabilities seem to be that the Flying Steamer Duck
(patachonicus) represents the common ancestral type which, through mutation,
has given rise to flightless species both in the Falklands and in South America.
THE STEAMER DUCKS 957
The bird of the latter region (preneres) has departed most widely from its ances-
tors, though the Falkland bird (brachypterus) has developed certain peculiarities
of its own, such as the glistening feathers that encircle the neck of the adult,
and the light natal down.
MAGELLANIC FLIGHTLESS STEAMER DUCK
Tachyeres pteneres
Anas pteneres Forster, 1844, Descrip. Animal., p. 338 (Tierra del Fuego).
Forster's detailed Latin description of the plumage, size, and habits leaves no doubt that he
referred to the Magellanic flightless species. He records a weight of ‘'16 libras’’ which, if he made
use of the Prussian pound in vogue until after 1840, would be equal to 7.48 kilograms, a weight
which is perhaps slightly excessive but could apply in any case only to the flightless bird. The
length recorded for the culmen in “‘uncia’’ amounts to 61.5 mm., which likewise fits the flightless
bird.
Forster evidently examined a number of specimens, however, for he describes both sexes in
full, and I believe that some of the measurements he records for length of body and wing-span
may refer to the smaller or flying species. While his description is perhaps to this extent a com-
posite, his name may justly be restricted on the weight of evidence to the larger or flightless species.
Names: Racehorse, Sea-horse, Loggerhead; the Spanish name ‘Pato Vapor”’ is, of course, a
translation of the English steamer duck. Aboriginal names used in Chile include “’Quetro,’’ which
is variously spelled. Synonyms of the specific names are cinereus, brachypterus, macropterus, and
patachonicus, two of which properly apply to the other two species.
Characters: A large, heavy steamer duck, the bill, leg, and foot of which are at all stages much
larger than the same structures in the flying species, while the wing and tail are relatively much
shorter.
Adult male: Head pale neutral gray, with a slightly mottled effect owing to partial exposure
of the lighter bases of the feathers, the pileum darker, forming a distinct cap; lores also prevail-
ingly darker than cheeks; a whitish streak extending from both eyelids caudad toward the auricular
region; a broad and elongate patch on the throat, varying in hue between brick-red and russet;
mantle, scapulars, back, rump, upper tail coverts, breast and flanks, slate-gray, with a more or
less scaled appearance owing to lighter centers on some of the feathers, and rarely with a slight
wine-colored tinge on the margins of feathers of the scapulars, lower back, and flanks; breast in
some specimens more or less tawny owing to a rufous mesial band present between the gray tips
and light bases of the feathers in this region; abdomen and under tail coverts white; wing with
carpal and metacarpal tuberosities, the latter forming a pronounced, rough, and dull-pointed spur;
primaries fuscous-black, as are also the rectrices; remainder of wing slate-gray, like the back,
except for a large and conspicuous white speculum formed by the tips of the greater coverts and
all of the outer secondaries; wing-lining centrally white. Iris brown, eyelid black; bill bright
yellow, orange and carunculated at the base, the nails of both maxilla and mandible black, of
pronounced relief, and of shiny, corneous surface; legs and feet yellow, with the soles and claws
blackish.
The general color of the head in adult males varies according to wear, the cheeks and the sides
of throat and neck becoming whitish as the tips of the gray feathers decompose; likewise the red-
dish spot on the throat is large and conspicuous only in fresh plumage, becoming almost obsolescent
with continued abrasion. Furthermore, there is considerable age or individual variation in this
mark, fledglings and young adults appearing to show less of it than thoroughly mature birds. It
seems, however, never to be entirely lacking.
Adult female: Generally similar to the male, but slightly smaller, with a tendency toward
more wine-colored scalation on the plumage of back and flanks, and with a darker head, the cheeks
and sides of throat being of a mottled dark vinaceous drab or dark purplish drab color instead of
gray; bill yellowish, rather than bright yellow, and usually of a much darker appearance in
dried skins.
958 OCEANIC BIRDS OF SOUTH AMERICA
13 males from various parts of southern South America, between Chiloé Island and the islets
south of Tierra del Fuego: wing, 260-288 (275); tail, 85-99 (93.5); exposed culmen, 55.2-64.5
(60); width of maxilla, 33.1-36.1 (34.6); width of maxillary nail, 15.4-18.5 (17.1); tarsus, 66-
78.6 (71.7) mm.
11 females, same localities: wing, 255-271 (263); tail, 85.5-93.8 (88.3); exposed culmen,
53.9-60.7 (58.6); width of maxilla, 31-33.3 (32); width of maxillary nail, 14.7-16.8 (15.7); tarsus,
63.4-70.6 (66.5); middle toe and claw, 99.6 mm.
Fledglings of both sexes in this species have the dark parts of the plumage entirely gray, with-
out wine-colored margins on the feathers of breast and flanks, the only exception being that the
reddish spot on the throat is clearly indicated. They closely resemble the young of the flying
species (patachonicus) at the same stage, but have about twice the bulk, with correspondingly
larger bills and feet.
In downy young of the three forms of steamer ducks, the specific characters show even more
markedly than they do at later stages. Young ducklings of premeres have the dorsal surface dark
bister-brown, with scarcely any trace of light spotting caudad from the head, on the sides of
which there are a pair of post-ocular white areas. A broad, definite grayish brown collar crosses
the throat and upper breast. The down of the whitish belly is somewhat hair-like and silky.
The bill is entirely blackish, broad, deep at the base, with the maxillary lamellae showing clearly
in lateral aspect; the nails of both maxilla and mandible are broad, distinct, and tumescent, with
a hard, polished integument. The mandibular rami tend to spread apart basally. The feet are
blackish in life.
The above description is based upon ducklings from 20 to 40 cm. in total length, the youngest
of which had not been more than a day or so out of the egg.
The eggs of all three species of steamer ducks have been badly mixed in the literature of all
dates, for which reason many of the recorded measurements are not to be trusted. All are ivory-
white or creamy, and the shape is variable within narrow limits, but the shells of eggs of the two
flightless species are thicker than those of the flying species, as pointed out by Lowe.
Our single full set of eggs of pteneres numbers six, but larger clutches have been frequently
reported. The average dimensions of 11 are 84.7 x 57.3 mm., the extremes measuring 88 x 61
and 81 x 55.
Distribution: Coasts and islands of southern South America from the vicinity of Corral, Chile,
southward to the islets near Cape Horn and Staten Island. Breeding from the Gulf of Anctd and
Chiloé Island to southern Fuegia, and in the western part of the Strait of Magellan.
According to Phillips, the first description of the Steamer Duck, and of its
habit of racing over the water at astonishing speed in the Magellanic region, is
that of Pedro Sarmiento de Gamboa (1580), who cruised from Callao toward
the southern tip of the continent. The shipwrecked sailors of Lord Anson's
fleet gave the bird the English name Racehorse ‘from the velocity with which
it moved upon the surface of the water, in a sort of half flying half-running
motion’’ (Byron, 1748, 50). Molina (1782, 239) refers to it as the Quetru,
under the curious technical name ‘'Diomedea chiloensis,’ which he describes as
a bird with an ash-colored, fluffy plumage of such soft texture that the inhabi-
tants of Chiloé, where the duck is abundant, spin the feathers and make bed
coverings of them. Both Phillips and Lowe cite many other early accounts,
and Darwin has written the following mu/tum in parvo, which calls for comment
in almost every line, and which, in fact, is a “‘design for a biography"’:
These great logger-headed ducks, which sometimes weigh as much as twenty-two pounds,
were called by the old navigators, from their extraordinary manner of paddling and splashing over
the water, race-horses, but now much more properly steamers. Their wings are too small and
weak to allow of flight, but by their aid, partly swimming and partly flapping the surface of the
MAGELLANIC FLIGHTLESS STEAMER DUCK 959
water, they move quickly. The manner is something like that by which the common house duck
escapes, when pursued by a dog; but I am nearly sure that the steamer moves its wings alternately,
instead of, as in other birds, both together. These clumsy birds make such a noise and splashing,
that the effect is most curious. The steamer is able to dive but a very short distance. It feeds
entirely on shell-fish from the floating kelp and tidal rocks; hence the beak and head are surpris-
ingly heavy and strong, for the purpose of breaking them. So strong is the head, that I have some-
times scarcely been able to fracture it with my geological hammer; and all our sportsmen soon
discovered how tenacious these birds were of life. When pluming themselves in the evening in a
flock they make an odd mixture of sounds, somewhat like bull-frogs within the tropics (Gould,
1841, 136).
As regards weight, the greatest of naturalists probably dropped his custom-
ary caution in crediting 22 pounds. That figure has, to be sure, been outdone
on paper, for Captain Cook records Steamer Ducks at Staten Island weighing
29 or 30 pounds. Such bulks, as Phillips notes, are patent exaggerations, but
the largest males doubtless attain a maximum of about 14 pounds (6350 grams).
Reynolds (in Lowe, 1934, 472) says of the progression of the Flightless
Steamer Duck: ‘‘It flaps over the sea at a great pace, throwing up so much
spray that at a distance it is the flying water rather than the bird that draws
the eye.’’ Cunningham (1871, 350) reports that flocks in motion sometimes
raise “‘a wave of surf fully a foot and a half in height."’ The wings and feet
both play a part in this churning of the water and, in another account, Reynolds
(1934, 350) notes that while the wings are beating, the long strides and back-
ward kick of the legs can also be observed. According to Phillips, the wings
are not moved alternately, as Darwin thought, but simultaneously as in any
other bird, although the great splashing gives the appearance of uneven loco-
motion. I believe, however, that something still remains to be said about this
point.
Darwin speaks of the wings as ‘‘weak."’ Rather, they are merely small and,
as Lowe has indicated, capable of somewhat limited extension. The bones,
muscles, and tendons are all well developed, and the pectoral muscles are fully
as massive as in a flying waterfowl of equal size. There is no reason to believe
that the Steamer Duck's method of making headway requires any less expendi-
ture of muscular energy than flight through the air; the probabilities would,
indeed, be the other way. As regards their rate, Gay (1847, 457) states that it
requires a boat with six oarsmen to overtake them, but most of the early writers
allege that the birds can outdistance any rowboat, however well manned. They
have been credited with speeds up to 15 miles per hour (24 k. p. h.). Beck found
that they would gain for a time when pursued by a launch making 8 miles an
hour, but that after a chase of 2 to 3 kilometers they would begin to weaken.
He learned, too, that the birds would rarely deign to change their course when
he tried to intercept them in a skiff. They would rely rather upon increasing
their speed at the critical time.
Darwin's statement that the Steamer Duck is able to dive but a short distance
doubtless deserves challenging, though there seems to be little to quote upon
the subject. Nicoll (1904, 49) writes that it dives well and remains under water
a ‘‘considerable time.’’ Reynolds adds that it ‘is, of course, an expert diver,
960 OCEANIC BIRDS OF SOUTH AMERICA
and in the beautifully clear waters of the Beagle Channel I have noted the
movement of its partially extended wings as it passed beneath the boat.’’ Old
and young alike, according to Blaauw (1916, 488), are accomplished divers, and
Beck found at Chiloé that the Steamer Ducks not only dive skilfully after
they have been exhausted by long pursuit, but that they are capable of swimming
with the body entirely submerged and the head barely above the surface.
As to the extraordinary toughness, tenacity of life, and “‘almost reptilian
vitality’? of the Flightless Steamer Duck, the experience of Percy and of all
other recent observers agrees with that of Darwin, who tested a skull with his
hammer! Beck's chief difficulty during his collecting work was not to hit the
birds, but to kill them; Nicoll found that even BB shot was effective only at a
range of 15 meters or so.
In Lowe's recent monograph on the Steamer Duck, Reynolds has pointed
out a fact of great zodgeographic significance, namely, that the flightless con-
tinental species avoids highly tidal coasts. It is absent, for example, along the
unbroken shores north and south of the eastern entrance of the Strait of Magel-
lan, where the daily ebb and flow of the tide attain record proportions. Along
the southerly and westerly sides of the Fuegian complex, however, and in the
rugged, broken channels that exhibit relatively little tidefall throughout their
extent northward along the Pacific coast to the Gulf of Anctd, this species is
everywhere at home. It reaches fresh water only about the mouths of streams,
if at all, and in its choice of nesting sites it shows a strong predilection for small
islets and points rather than for the shores of bights and coves. Such infor-
mation clarifies many published notes regarding the ranges of the Flightless and
Flying Steamer Ducks, and gives at least a provisional clue to the identity of
specimens recorded from the east coast of Patagonia. De Agostini (1924, 114)
reports that the flightless species, as he observed it in Tierra de] Fuego and Staten
Island, never ventures farther than 10 kilometers from any shore.
During the Brewster-Sanford Expedition, Beck first became acquainted with
Steamer Ducks along the shores of Chiloé. Here, in April, May, and June, 1914,
he found birds of both the flightless and the flying species together, although
between December and February of another year no flying birds whatsoever
were to be found in this same region (Chapman, 1933, 361; Percy, 1934, 867).
The supposition is that during the latter season the flying birds were nesting
around lakes or up streams, at a distance from salt water.
On the water and on islets off Ancid, and also in many coves near the south-
western corner of Chiloé, Beck found the flightless birds common, associating
either in small flocks or in pairs. Single birds were rarely if ever to be seen, and
it is of interest that Reynolds believes that all forms of steamer ducks mate for
life. Most of the birds encountered by Beck at Chiloé had to be taken by strat-
egy, principally by approaching them from the windward or by giving chase
in a launch until they took to diving and eventually made a miscalculation.
Southward through the Chilean Archipelago, the western half of the Strait
of Magellan, and along the channels leading toward Cape Horn, Beck found
the Flightless Steamer Duck everywhere common. On the shore of O'Brien
MAGELLANIC FLIGHTLESS STEAMER DUCK 961
Island, on January 14, 1915, he saw a flock of nearly a hundred, and in neighbor-
‘ing waters were many broods of young of various ages, including ducklings as
small as others he had met in the vicinity forty days earlier. Five newly hatched
birds had been observed at London Island on November 30. Reynolds (1935, 84)
has recently reported that “‘contrary to expectation’’ the Flightless Steamer
Duck proved to be the commoner breeding species near Cape Horn in December,
1932. He found pairs, solitary males standing guard, and family parties with
small young at Barnevelt Islet, to eastward of Deceit.
Aside from some thirty mature Flightless Steamer Ducks obtained by Beck
between Chiloé and the Cape Horn district, he also collected downy ducklings
as follows:
One male and two females, apparently of a single brood, London Island,
November 30, 1914.
One male, Stewart Island, December 3.
One male, Timbales Island, December 4.
Two males, apparently of one brood, Beagle Channel, January 11, 1915.
Older young, and fledglings with very short, sprouting primaries include
odd birds or entire broods taken in Cockburn Channel, March 5; Bertrand Island,
April 22; Gable Island, Beagle Channel, May 4; Chiloé, May 19; and Ushuaia,
July 19. Although many of the fledglings look like examples of Tachyeres
patachonicus at the same stage of growth, they are readily distinguishable by
size, the length and thickness of the tarsus and foot, the form of the bill, and
the much more marked tumescence of the ungues of both maxilla and mandible.
Most of the adults taken by Beck at Chiloé in May were in worn and moult-
ing plumage, one or two being so ragged that the dense gray undercoat of down
shows through the sparse feathers. In these and other examples some of the
remiges had become frayed practically down to the shaft as a result of their
frequent battering against the water. Among most such birds the two outer-
most primaries were new, the inner ones at the point of being shed in sequence.
Beck believed that females shot in June already exhibited incipient enlargement
of the ovaries in anticipation of the courtship season, which probably begins
two months later or thereabouts. Percy found that almost all the ducks had
young at Chiloé by December 20.
The relative wariness or tameness of the Continental Flightless Steamer
Ducks seems to be determined in part by their experience. Percy reports that
wherever they are unmolested they are not naturally shy or wild, but a very
little persecution makes them so, and they then exhibit excellent judgment in
the selection of rocks upon which to rest, places that are unapproachable from
any direction without warning. At Melinka, in the Guaitecas group, Blaauw
remarks that they become almost as tame as domestic ducks. In their daily
movements, according to Phillips, who quotes Percy and others, they are day-
feeders, like other sea ducks. Regularly, and usually more than once in 24
hours, they leave the salt water around such a locality as Chiloé, and go inland
to drink at springs of fresh water. The individuals seem to be highly sedentary
creatures both afloat and ashore, with a strong penchant for particular coves,
962 OCEANIC BIRDS OF SOUTH AMERICA
kelp beds, roosting rocks, etc., throughout the year. Large flocks usually
prove to be made up of yearlings or other immature birds. Feeding time is
chiefly at high water, when the ducks forage along the fringes of the kelp
fields. As soon as the rocks are uncovered they split up into pairs or small
parties, clamber onto their favorite perches, and spend hours resting, preening,
and quarreling. They accept the responsibility of defending the rock upon which
they sit against all comers, opening their beaks and ‘making faces”’ at any ap-
proaching bird. Small groups get along peaceably enough, and manage to sleep
for long stretches, but under conditions of a concentrated population, there is
always a constant movement caused by the never-ending demand for a good rock.
Reynolds, in Lowe's paper, thus defines the Flightless Steamer Duck's de-
fense of territory in courtship, etc.
A warlike bird, with a singular method of attack, it fights its like and chases the smaller
flying kind, T. patachonicus. The approach is identical in both cases. It flattens itself out, head
down, neck extended, swims almost submerged, gradually disappears, and reaches its unsuspecting
adversary from beneath. I have not noticed T. patachonicus do this, and do not believe it has the
habit. My mother remembers seeing fighting Steamer Ducks . . . picked up by Yahgan Indians
in a canoe, and that when adults were engaged in strife the young often took refuge on land.
Even more detailed account of the contests between rival male Steamer
Ducks will be found in the biography of the Falkland flightless species.
Reynolds continues that the continental species nests abundantly on islets
of Beagle Channel, and on promontories of the Fuegian mainland. The nest is
rarely as far as 300 meters from water, and usually close to the edge of it. The
eggs, which usually number from five to eight, are laid under shrubbery or other
concealment. A nest found by Beck within a few steps of the water at Isla
Grande, on December 2, 1914, was well lined with down and contained six
slightly incubated eggs. Reynolds writes:
The duck sits exceedingly close, and must be nearly trodden on before she moves; moreover,
she takes full advantage of unlimited cover found everywhere in the form of vast tangles of bush
and shrub. The drake, by swimming up and down and calling, and when most excited accompany-
ing his calls with an angry shaking of the head, does his best to give the nest away.
Nicoll reports that the Steamer Duck's call-note to the young is a croaking
quack. Cunningham (1868, 127) reports two very distinct notes, one like the
mew of a cat, the other a sort of low, hoarse growl. Falkland observations
suggest that the latter of these pertains to the male, the mew to his mate.
Percy found that the male of the continental flightless form has a variety of
notes, that most frequently heard being a shrill qu-7-e-w-/] repeated about twenty
times, after which there is a quick kek-kek-kek-kek. The last is, however, some-
times left out (Phillips, 1925, 294).
Mollusks of many sorts make up the principal part of the Flightless Steamer
Duck’s food, though fish and various crustaceans have likewise been found in
their stomachs. Since they obtain the bulk of their food from the kelp beds,
they do not have to dive deeply. Beck found small shells and gravel in the
stomachs of very small downy young, and mussels (Mytilus) up to 55 milli-
meters in length, chitons, limpets, and snails in those of adults. A male taken
MAGELLANIC FLIGHTLESS STEAMER DUCK 963
at Magallanes in late July, 1914, contained a conical marine snail (Euthria)
32 millimeters in length and 14 in diameter, a chiton (Plaxiphora setiger) about
27 millimeters in length, and 12 imperforate limpets (Nacella fuegiensis) measur-
ing up to 38 millimeters in length, 27 in breadth, and 12 in the height of the
shell. The power of the ducks’ gizzards to crush and triturate such objects is
most impressive. Percy found that 12 birds taken at Chiloé in December and
January were crammed to the gullet with small crustaceans of the kelp, resem-
bling a ‘‘'wood-louse.”’
Little is known of the Steamer Duck's gnemies, but the mortality of the
young is obviously high. Beck once saw a caracara destroy three out of a set
of four eggs in a nest near the Strait of Magellan. Reynolds states that even
the adults fall victims to the foxes along Beagle Channel.
The following quotations are from the notes of Lord William Percy, as
published by Phillips (1925, 292 and 296):
The immature and non-breeding birds were in small parties or large packs which seemed to
consist of one-, two-, and three-year-old birds and very few showed the white head of the adult
male. The daily habit of these packs, one of which numbered 83 birds in the Guaytecas Islands,
and another 87 birds at Pumalin (i.e., Yelcho on the mainland), was to feed during high water
along the fringe of kelp, and so soon as the rocks became uncovered, to split up into small parties,
or more generally pairs, clamber up on to the rocks and spend the hours of low water preening
and quarrelling. They are then most entertaining birds to watch for they seem possessed of only
one idea apart from sleeping and preening and that is to defend the rock upon which they sit
against all comers. There would always be birds floating along the edge of the rocks which had
not found a suitable perch, and the possessors of a rock, if unable to deter newcomers from joining
them by opening their beaks and ‘making faces’ at them, were frequently compelled to withstand
a direct assault. The newcomer is generally repelled as he is at a disadvantage in clambouring
up the rock, but such slight assistance as a swell giving him the necessary impetus not infrequently
enables him to displace the holders of the rock of which the newcomer or newcomers then proudly
take possession, ruffling up their feathers and ‘making one more face at the departing forms of
the dispossessed. A small party is generally fairly friendly and will sleep peaceably for hours but
amongst a large pack there is always a constant movement caused by this continual demand for a
good rock.
The most interesting habit of these birds which I noticed on the small islands off Chiloé was
that they regularly left rhe sea more than once in the 24 hours and went considerable distances
inland to springs of fresh water. On one island solely inhabited by breeding pairs, there were
several large caves extending more than 100 yards into the hillside. At the head of these caves,
and also at other places more than 300 yards from the sea and through more or less dense vegetation,
were small trickles of fresh water coming down the rocks. All round these spots the ground was
trampled down and covered with the tracks of Steamer Ducks, and between every tide the fresh
tracks of the birds could be seen imprinted in the sand leading from the sea and back to it. The
tracks of broods were never seen at these places, but on one occasion in Jan. 1924 a pair of old birds
with four downy young were discovered at the head of one of the largest caves. The male and two
young broke past in the dark but the female was struck by a native with a stick and two of the
young caught. All three were kept by one of the inhabitants of Ancud for some weeks but the
female had been injured by the stick and eventually they all died.
The natives say that the old birds go to the springs to drink fresh water and that they take
their young to the caves to roost. That they nest on occasion in the caves is evident from several
old nests which were seen, but it seems improbable that such a marine duck as a Steamer Duck re-
quires fresh water. I noticed that there was a fine green slime where the water dripped down the
rock and on one occasion saw a pair of old birds in another locality apparently ‘grazing’ ona large
sloping face of rock where on subsequent inspection nothing could be seen but this same green
964 OCEANIC BIRDS OF SOUTH AMERICA
slime. Whatever be the explanation of these extended peregrinations on dry land they constitute
an interesting, and as far as sea ducks are concerned, unique habit in my experience.
I think it is worth while to quote the following remarkable experience which William Percy
had with a family of Steamer Ducks, for it shows that they are endowed with a very different
psychological make-up from that seen among our more typical northern ducks. He writes:
“On Jan. 2, 1924, I was sitting on a small island in the Guaytecas group when a pair of Steamer
Ducks with a brood of six came swimming amongst the kelp within 40 yards. They fed there for
one half hour gradually getting to within 25 yards of where I lay. The young were not more than
a week old and as I required a bird of that stage I finally decided to shoot one. Choosing the
moment when one bird was separated from the rest I fired and killed it, turning it over in the
water so that it lay on its back. The rest of the brood immediately took refuge at their mother’s
side and she and the male remained perfectly still where they were. I did not move and was then
vouchsafed the most remarkable display of emotion that I have ever witnessed in a duck. The
male remained gazing at the splash made by the shot for perhaps three seconds, then gave a harsh
cry at which the remaining young dived at once. Then ‘steaming’ straight at the dead bird with
beak wide open, and lashing the water into foam with wings and feet, he appeared on reaching it
to be about to give it a violent blow with his bill, but instead dived under when within six inches
of the dead body, reappeared a few yards beyond, ‘steamed’ on 15 yards, and then turned about and
repeated the process. He must have repeated this performance 15 or 20 times before I was tempted
to end his pathetic frenzy by shooting him, when he suddenly stopped, joined the female who had
remained quite stationary with her brood at her side all the time, and went slowly off to sea
apparently quite unconcerned. I had not moved, and do not think the birds had seen me at all.
It seemed as though the male, on seeing the splash made by the shot, and his dead offspring in the
middle of it, had concluded that something under water had done the damage, and I am now con-
vinced that the rest of the performance was an attack on a supposed submarine enemy. In any
case it was a most impressive spectacle which displayed as no other experience with these birds did,
the astounding power which they can exert in the water, the surface of which was made to foam
and boil as if a large fish was causing the disturbance."’
FALKLAND FLIGHTLESS STEAMER DUCK
Tachyeres brachypterus
Anas brachyptera Latham, 1790, Ind. Orn., 2, p. 834 (Falkland Islands).
Names: Called Loggerhead at the Falklands to distinguish it from the Flying Steamer Duck or
“Canvasback.’’ The synonyms of the specific name are the same as those for the other two species.
Characters: A flightless duck, generally similar to the preceding species, but with a close
superficial resemblance to the Flying Steamer Duck. Bill narrower than in pteneres, the maxillary
unguis smaller in both diameters, and distinctly less hooked.
Adult male: Resembling Tachyeres pteneres, but head more whitish, the cap of darker gray
being much less pronounced; neck with a distinct silken yellowish or golden sheen never present
in pteneres; dorsal plumage much warmer in hue, approaching violet-gray, and the feathers of back
and flanks with extensive wine-colored or auburn margins, approaching the condition in the
species patachonicus; red color of the throat darker and richer than in preneres, being close to mahog-
any-red or bay and, instead of being confined to a central ellipsoidal area, it tends to spread widely
onto the sides of the neck and even to the face. Flesh colors apparently as in males of the former
species.
o Younger males exactly resemble females, which are described below. Three such collected by
Beck, and others collected by Brooks for the Museum of Comparative ZoGlogy, are indistinguish-
able from the eight adult females upon which the following description is based.
Adult female: Smaller than the male, with a bill which is greenish yellow (very dark green in
dried skins); plumage of the entire back, sides of breast, and flanks even more pronouncedly scaled
than in male birds, the breast sometimes becoming strongly rufescent with the wearing away of
the gray tips of the feathers in this region; base of neck showing a glossy, golden yellow ring,
FALKLAND FLIGHTLESS STEAMER DUCK 965
somewhat indefinite in extent, but more pronounced than the same feature in males, and peculiar
to this species; remainder of head and neck, except for the white ocular streak and an indistinct
grayish crown, dark reddish, of a tone somewhat more purplish than the “‘bay’’ of Ridgway’s
“Color Standards." Beck records the bill as*’ greenish, yellowish on the top,”’ the feet as yellowish,
with the webs and soles blackish. :
7 males from the Falklands: wing, 272-282 (276); tail, 91.5-101.6 (96.7); exposed culmen,
53-60.8 (55.3); width of maxilla, 30-32.5 (30.9); width of maxillary nail, 11.9-14.2 (13.3); tarsus,
63.1-67 (65.4); middle toe and claw, 96.8 mm.
8 females: wing, 251-274 (261); tail, 87.2-99.5 (93.4); exposed culmen, 52-58.3 (54.8); width
of maxilla, 26.9-30.1 (28.4); width of maxillary nail, 11.8-13.6 (12.9); tarsus, 55.2-62.8 (59.5) mm.
I have not seen fledglings of this species, and so can state no peculiarities of their plumage.
They would be readily identifiable, however, by bill characters alone.
In newly hatched young, the color and pattern are very different from the same stage in either
of the two other species. Ducklings of the Falkland flightless bird are dorsally of very much paler
brown than preneres, and have a unique gray collar across the upper back. The white mark behind
the eye and cheek is continuous instead of being interrupted so as to form two spots. In brachyp-
terus, indeed, the supra-ocular stripe beginning at the base of the bill is continuous with a broader
post-auricular stripe which extends to the back of the head. The form of the bill resembles that
of pteneres, but the maxillary and mandibular ungues are considerably narrower and of less pro-
nounced relief.
We have one set of six eggs. The measurements of these and four other Falkland eggs recorded
by Lowe give an average of 82.1 x 56.6, and extremes of 86 x 57, 79 x 57, and 80.3 x 55.4 mm.
Distribution: Endemic at the Falkland Islands.
The name Loggerhead, as applied to steamer ducks, probably originated at
the Falklands. It was used by Clayton (1776, 104), who describes the speedy
flapping of these birds across the water. He writes also that when they are
driven ashore they are capable of running very fast for a short distance, but
that as soon as they tire they squat and allow themselves to be caught. Both
Flightless and Flying Steamer Ducks were well known at the Falklands in
early days, but the latter have assuredly become rare, while the native flightless
ducks are still abundant and generally distributed. In consideration of the
respective salt- and fresh-water proclivities of the two, Bennett has suggested
the appropriate names Sea-logger and Lake-logger.
It would doubtless be acceptable and conventional procedure to regard the
Falkland and continental Steamer Ducks as subspecies of a common species,
rather than to grant each full specific rank. The reason why I have chosen a
different course has, however, an excellent measure of justification. It has to
do with the fact that the Falkland flightless bird has a particularly strong
resemblance to the flying species. Except for the shortness of its wings, and its
hypertrophied size, it shows, indeed, many signs of closer affinity with pata-
chonicus than with pteneres. This fact, no doubt, accounts for a misconception
of Phillips, who writes that in the Falklands certain males of the large gray
type of steamer duck mate with small females of the red type. The field ob-
servations and collections of Beck and Brooks show that both adult females
and immature males of brachypterus are superficial counterparts of some examples
of patachonicus, but that the differences are, nevertheless, constant. Under such
circumstances, I believe that the recognition of three species is the better con-
clusion in the present state of our knowledge. Beck's diary for October 22,
966 OCEANIC BIRDS OF SOUTH AMERICA
~
1915, contains the extraordinarily acute observation that the “‘steaming”’
Flightless Loggerheads of the Falklands regularly rise higher out of water,
when running at full speed, than do the non-flying birds of the,continent. Thus,
functionally as well as in appearance, the Falkland flightless duck is somewhat
intermediate between the two other species.
The members of the ‘Challenger’ party were much impressed by the tameness
of the Falkland Loggerheads, in contrast with the extreme wildness of their
relatives in the Strait of Magellan. As Thomson (1878, 179) points out, the
former had been safe in their island solitude up to within a recent period,
whereas the Magellanic ducks had been undergoing selection for ages upon the
basis of their capacity for eluding hungry Indians. Even today, after much more
than a century of human occupation, the Falkland Loggerheads are still noto-
riously tame, the Fuegian birds as wild as formerly but probably no more so.
The lack of shyness of the Falkland ducks is therefore to be regarded as a genetic
trait, like that of many species of the Galapagos Archipelago, and not as mainly
related to the birds’ individual experience.
Beck made the greater part of his collection of Falkland Flightless Logger-
heads in the vicinity of Port Stanley, where nesting birds were common during
October, 1915. On November 4 he saw a number of broods of five or six newly
hatched downy young in Berkeley Sound. A half-grown duckling was collected
on December 15, besides which I have had for comparison the three younger
birds taken by Brooks at Port Stephens, West Falkland, also during December.
On October 17 Beck discovered a nest with six fresh eggs in a sand-drifted hum-
mock on the beach near Port Stanley, only a step or two from the water.
Cobb (1910, 66; 1934, 80) and Vallentin (1924, 322) have given us fairly
comprehensive pictures of the Falkland Loggerhead, adding their own keen
observations to the data recorded by earlier workers such as Abbott. In
the absence of other marine ducks, the Logger has the ocean pretty much to
itself, though it is often rather closely associated with cormorants, gulls, and
grebes.
When they start scuttling or ‘‘steaming,’’ according to Cobb, the ducks
flap their wings simultaneously, changing to alternate strokes after they have
got up speed. Vallentin also believes that they sometimes beat the water in
this way, which agrees with the opinion of Darwin. Perhaps motion picture
records made at close range will be the only way to decide this moot point.
Early in the austral spring, the male Loggerheads establish a claim to nesting
territory by remaining close to the shores of their choice and entering into
combat with all rivals. Vallentin says that pairs not infrequently invade the
holdings of other pairs, the male leading. Both sexes then take part in the
encounters, rushing forward, each duck trying to seize an opponent by the
neck and to hold its head under water while beating with the hard callosities
on the wings. The struggling birds spin round and round, making such a com-
motion in the water that the eye cannot follow their movements. If one suc-
ceeds in submerging the head of the other, the beating is redoubled and the
water is frequently reddened by blood. A defeated bird makes its escape as best
FALKLAND FLIGHTLESS STEAMER DUCK 967
it can, and the victor paddles off uttering growls of joy, while his mate expresses
the same triumphant emotion by mewing like a cat.
Nesting commences in September or early October, although Cobb states
that odd nests in use have been found throughout the year. The nest 1s usually
close to the sea, but may be placed some distance back if there is no concealing
growth of diddle-dee or other vegetation at the verge of the water. At times a
mass of dry kelp just above high watermark, a clump of tussock, or an aban-
doned Jackass Penguin burrow may suffice as a hiding place. The nest itself is
a scoop in the soil, well lined with down from the mother’s breast. The eggs
number anywhere from four to ten, or even eleven, though clutches of six, seven,
or eight are the most common. Vallentin has found new-laid complete sets
between October 12 and November 9. Only completely fresh eggs are palatable,
and these are collected for eating in the Falklands, and are even pickled for
winter use.
While the duck incubates, the drake patrols offshore, uttering his bullfrog
note of alarm at the sight of an intruder. After incubation is under way, the
duck will sit until your foot, or that of your horse, is at the point of stepping
upon her, whereupon she will go off with a great fluster and hullabaloo.
As noted above, Beck saw the first ducklings on November 4, and Brooks
(1917, 156) reports new broods up to December 26. They are, of course, able
to dive well as soon as they hatch. At this time the parents lose their tameness
and become very wary, leading the brood well offshore at the distant approach
of a man. It is a pretty sight when a family is riding a choppy sea, the infants
striving to keep close behind their parents. If the brood is taken so by surprise
that there is no time for an orderly retreat, the female makes off with the duck-
lings while the old man valiantly stands rear guard. Big broods seldom last
long, for the youngsters get picked off by skuas and gulls. Vallentin tells of a
brood composed of seven in January which had diminished to a solitary fledgling
by March.
When the ducklings are old enough to fend for themselves, the adults drive
their own offspring out of the home territory, not hesitating to dive beneath
them or “‘steam’’ toward them with apparent ferocity, and to strike with the
spurred or knobbed wings. The fledglings thereupon congregate in flocks of
hundreds, remaining in such formations, according to Cobb, throughout the
winter and the following breeding season, and thus not nesting until they are
at least two years old. Such packs move about without scattering, resting on
beaches and flats, occasionally crossing to ponds close behind the beaches, but
apparently doing all of their feeding in the sea. When one bird dives, they all
go down, remaining beneath the surface for about 15 seconds, and then shooting
up more or less simultaneously in the manner of our northern-hemisphere
scoters. Both fledglings and adults are fond of dipping in shoal water along
stony beaches. They make an unusual amount of noise when diving, writes
Brooks, and on a quiet evening the splashes suggest the rising of trout in some
northern ‘‘still-water.”’
Phillips states that the grunting or bullfrog call of the Loggerhead is usually
968 OCEANIC BIRDS OF SOUTH AMERICA
attributed to the female, although both Darwin and Vallentin credit it to the
male. Brooks describes the regular note of the female Falkland Loggerhead as
a hoarse, rasping, snoring sound which can be heard at a considerable distance.
The ordinary note of the drake he calls thin and wheezy—kée-u-kée-u-kée-u—
more like a sneeze than anything else.
Their food includes all manner of small marine animal life. A single stomach dissected con-
tained limpets, small chitons, mussels, various gastropods and bivalves, shrimps, and two species
of crabs, the carapace of the larger being two inches long by one inch wide which with its legs
must have been a large object to swallow (Brooks, 1917, 156).
A female skinned by Cobb contained more than 450 mussel shells of various
sizes; a drake, three crabs and a quantity of sand and bivalves. Beck recovered
limpets, other mollusks, crustaceans, and “‘small bugs.’’ Vallentin reports
echinoderms (Hemiaster) and adds that the strong beaks of the Loggerheads
can break almost any bivalve in the Falkland region.
The Loggerheads show evident fear of sea-lions at the Falklands, and some-
times make toward the land to escape from or avoid them (Vallentin). On the
other hand, a creature ashore, such as a dog, may excite their curiosity enough
to cause al] the birds within eyeshot to swim toward it.
FLYING STEAMER DUCK
Tachyeres patachonicus
Micropterus patachonicus King, 1830, Proc. Zod]. Soc. London, 15 (western part of the Strait of Magellan).
King’s description is completely diagnostic. He states that the bird he is describing is grayish
lead-color above, with the throat and scapulars rufescent, the abdomen and the speculum of the
wing white, the bill greenish black with a black nail, and that it is of lesser size than “‘Micropterus
brachypterus’’ by which he meant, of course, the mainland, rather than the Falkland, flightless species.
Names: Canvasback at the Falkland Islands. The synonyms of the specific name are those of
the other two species.
Characters: Smaller than either of the preceding species, with wing and tail of greater absolute,
as well as relative, length, a bill of different shape as well as lesser size, and a notably shorter and
more slender tarsus.
Adult male: Similar in general plumage-pattern to the male of preneres but with a stronger
tendency toward rufescent scalation on the back, scapulars, and flanks. Iris brown; bill orange-
yellow, with bluish areas around nostrils, paling to whitish toward the tip; unguis black; legs
and feet yellow, the webs dark.
The oldest males, as indicated by maximum size and by bills which remain yellow even in
dried skins, are also the least rufescent. They have clear gray heads, except for the white post-
ocular stripe and the reddish throat patch. Younger males resemble females in the extension of
reddish coloration to the sides of the head or even to the forehead and crown. The color of their
bills also resembles that of females.
Adult female: Similar in color and pattern of plumage to the female of brachypterus. Bill yel-
lowish on the culmen, blue along the cutting edge, the very small and narrow maxillary unguis
being black. The dertrum, or nail of the mandible, has very little tumescence, and in dried skins
is practically of the same color as the dark mandibular rami.
17 males from Chiloé Island, many localities in and about Tierra del Fuego, and the Falkland
Islands: wing, 287-316 (300); tail, 92.4-123.4 (107.1); exposed culmen, 48.2-56.8 (52.4); width
of maxilla, 25.1-28.9 (27.2); width of maxillary nail, 10.6-13 (11.7); tarsus, 55.4-69.3 (60.8);
middle toe and claw, 90-95.2 (92) mm.
FLYING STEAMER DUCK 969
23 females from Chiloé, the Strait of Magellan, Tierra del Fuego and adjacent islets: wing,
276-301 (285); tail, 88.7-105.5 (98.9); exposed culmen, 50-59.3 (52.3); width of maxilla, 22-27.3
(25.4); width of maxillary nail, 9.8-12.3 (10.8); tarsus, 50.3-60.7 (56.4); middle toe and claw,
80-87 (84.1) mm.
Fledglings of this species have little more than half the bulk of the young of preneres at the
same stage of growth. Aside from size and the well-marked difference in bill formation, the two
are practically alike, although patachonicus shows a faint rufescent wash on the feathers of wings,
back, and flanks, such as is not detectable in the larger species. The pattern of gray on the head
and of red on the throat is the same in the two.
The duckling of this species has been sufficiently described in the introductory section. Diag-
nostic characters show in the plumage-pattern, the structure of the bill, and in size, besides which
Lowe has pointed out more deep-seated morphological distinctions.
Vallentin (1924, 322) states that the eggs of the Flying Steamer Duck are more regularly oval
than those of the Falkland flightless bird, but this opinion is to be received with caution because
some of the measurements he records obviously refer to eggs of brachypterus rather than of pata-
chonicus. The latter bird is relatively rare in the Falkland Islands and, because of its superficial
resemblance to the local flightless species, popular confusion concerning the two is even worse
than in other parts of the steamer ducks’ range.
From the Fuegian region, 29 positively identified eggs of patachonicus have average dimensions
of 76.4 x 52; extremes measure 77 x 53 and 75 x 51 mm.
Distribution: Southern South America and the Falkland Islands. The continental range is
apparently the same as that of Tachyeres pteneres, except that it includes also some of the lakes of
eastern Patagonia and other inland bodies of fresh water, and extends eastward to coasts of exten-
sive daily tidal fluctuation in Tierra del Fuego, and northward along Atlantic shores to about
latitude 48° S
Reynolds (in Lowe, 1934, 474) summarizes the behavior of the Flying
Steamer Duck as follows:
Tachyeres patachonicus is capable of sustained and rapid if somewhat heavy flight. Not infre-
quently, especially in summer, it takes what appear to be joy-rides over land. Two, three, or four
individuals leave the sea together, flying inland. They either describe a huge semicircle, returning
to the beach, or they may go completely round and pass the observer a second time. At intervals
during these flights, but for short periods only, they simultaneously check the rapid movement
of the wings, and stoop downwards, pausing momentarily after each successive wing-beat. The
effect is curious, and unparalleled by any other Fuegian Duck.
At times T. patachonicus may well be taken for a flightless bird, and some of the confusion in
distinguishing between the two species is probably due to the unaccountable reluctance to rise
so often demonstrated by this species. Commonly on the sea it may be shot at or otherwise alarmed,
and, instead of flying, dives and then steams, or simply steams out of range. It steams in the same
manner as the larger flightless bird, but its progress is more buoyant. It does not kick up so much
spray, and its speed is, I should think, greater. In summer it is constantly seen on the wing on all
sides; in winter it rises less often, but in places sleeps regularly on ice at some distance from the sea.
Mr. Beck first met the Flying Steamer Duck in the mouth of the river at
Anctd, Chiloé, on May 1, 1914. A pair came flying past his boat, and when
he winged one the other bird circled back so that he was able to collect it also.
On this and subsequent occasions he found the flying birds much easier to kill
than the low-floating, flint-headed flightless ducks, which paid no more atten-
tion to No. 6 shot than to snowflakes, and which sometimes recovered and
“steamed” out of sight after being knocked over with a charge of No. 3.
Near Cuellon, Chiloé, on May 19, Beck recognized one pair of Flying Steamer
Ducks resting on the water among many flightless birds. They took wing as
970 OCEANIC BIRDS OF SOUTH AMERICA
his boat drew near, and he shot them both. The incident deserves mention
because it indicates the distinctive appearance of the flying species. Since
steamer ducks usually swim with their tails carried upright, the greater length
of the rectrices gives the flying birds a much more long-tailed look than
that of the flightless species. Furthermore, when Flying Steamer Ducks
“‘steam,"’ they often end by lifting themselves until their bellies and feet are
just clear of the water, and then proceed at this level, with the tips of
their wings barely touching the surface at every stroke. On the other hand,
they are capable of getting well into the air within a space of 2 meters, even
in a dead calm.
In early June, during a period of very rainy and windy weather, Beck devoted
much time to the pursuit of Flying Steamer Ducks in the bay of Ancid. On
June 6 he encountered about a hundred ducks of both species, mostly in groups
of from four to fifteen, on or near a spit which blocked an inlet. Some of them
flew off at his approach. By working to windward of a pair, he shot the female,
but the drake continued and subsequently pitched close to a couple of big
Flightless Loggerheads. Beck gave chase to the three, and learned that the
flying bird swam a trifle more slowly than the flightless pair. The former took
wing, after it had fallen behind, and flew about 200 meters before settling again
on the water. By continuing his tactics of keeping to windward, Beck collected
on this day eleven Flying Steamer Ducks. They rarely dived at the approach
of his craft, but preferred to take wing. Some of them flew heavily, not rising
far above the water, while others mounted high into the air and passed quite
out of sight.
On June 10, Beck saw many more of the Flying Steamer Ducks in pairs and
small groups. After he had routed them several times by his efforts to collect
specimens, some of the birds flew a distance of 5 kilometers, into the very head
of the bay. Beck pursued the groups from the middle of the forenoon until
3.15 p.m., pulling as hard as he could row in his skiff, working alone, and allow-
ing the dead ducks to float in clusters on the water in order to lighten the boat.
He collected 18 flying birds, the males of which had an average weight of 3175
grams and the females of 2665 grams. He notes that of the birds to which he
gave chase on this day, nearly all rose high into the air, not more than six
““steaming’’ away from his boat. Aside from the characters of behavior, Beck
noted that the black nail of the bill in the freshly killed flying ducks was much
smaller than the nail of even fledgling examples of the flightless species. The
tubercles on the wrist were paired in the flying as in the flightless species, but
of considerably lesser size in the former.
Many of the Chiloé birds taken in June, particularly the females, showed
distinct signs of the annual enlargement of their ova. The most richly colored
of the males had bright orange-yellow bills, but the less mature males and all
of the females showed more or less bluish in their bills. Furthermore, the bills
of many old birds were somewhat carunculated at the base, this being a a
ter sometimes alleged to be restricted to the flightless species.
Farther southward, toward the tip of the continent, Beck met with many
FLYING STEAMER DUCK 971
Flying Steamer Ducks on salt water during their breeding season. Reynolds
writes of the species in Tierra del Fuego:
In winter it is restricted to the coast, where in summer many breed; but others penetrate far
inland, spreading wherever there is water from the sea to the mountains. Hantu Lake, 28 miles
from the Atlantic, is a favourite nesting ground. I have seen plenty of pairs with ducklings there,
and have two eggs in my collection taken from its shore (in Lowe, 1934, 475).
Beck found only a few of the Flying Steamer Ducks at Deceit Island, and else-
where close to Cape Horn. Reynolds (1935, 85) has since reported that it is
much rarer here than the flightless species, although he found a pair or two
breeding on Grévy Island in December, 1932, and caught a female as she flew
off the nest. At Ushuaia and in other parts of Beagle Channel, Beck found the
flying species at least as common as the flightless during the latter half of July.
This was in the middle of the austral winter, and many full-grown young were
with the adults. Reynolds, too, says that the flying species is no less common
than the other in Beagle Channel, while on the long northeastern coast of Tierra
del Fuego, where the flightless species is not to be found at all, the flying bird
is more abundant than elsewhere.
At Punta Delgada, on the Strait of Magellan, Beck shot a steamer duck in
flight between a pond and the salt water on July 23, 1914. Aside from this and
other adults collected in the Fuegian region, he obtained a male and a female
young duckling, apparently of the same brood, and two females of another and
older brood, at Stewart Island, on December 3, 1914. It is noteworthy that
downy young of both the flying and the flightless species were collected at
Stewart Island on the same date. Another downy youngster was collected at
Isla Grande on December 4.
Fledglings of the flying species, no less than those of the flightless, acquire
their wing quills very slowly, so that they have only barely sprouted primaries
for a considerable period after the down has entirely disappeared. Three of the
flying species in this stage were taken at Ushuaia on April 1. At the same
period adults in the vicinity had lost most of their rectrices, while the remiges
were in the midst of moult, old worn primaries standing in juxtaposition with
fresh ones.
At the Falklands the Flying Steamer Duck, or ‘‘Canvasback’’ is now rela-
tively rare, whatever its status may have been in the early days. Perhaps the
statement by Bennett (1924, 280) that the flesh of the flying bird is excellent
eating, while that of the Flightless Loggerhead is inedible, tells the story.
At any rate, Beck observed very few of the flying species during his extensive
Falkland field work, and collected only a single pair at Bleaker Island, Decem-
ber 12, 1915. Popular confusion regarding the steamer ducks is, as already
noted, worse in the Falkland Islands than anywhere else, chiefly because of the
close resemblance in plumage between the flying and the insular flightless
species. The islanders know that some of the ducks can fly, but most of their
other criteria of discrimination are worthless. Neither Beck nor Brooks (1917,
155) received any really helpful information from the friendly Falklanders on
this point, and the literature shows that descriptions of the appearance and
972 OCEANIC BIRDS OF SOUTH AMERICA
habits of the ‘‘Canvasback’’ and the ‘“‘Loggerhead’” are a largely hopeless
muddle. If Brooks had succeeded in collecting any flying birds, he would no
doubt have solved the problem, for his comments on Blaauw’s discussion are
exceedingly shrewd. One might say, indeed, that the truth about these trouble-
some birds has been barely missed on a number of occasions.
The Flying Steamer Duck is equally at home in either fresh or salt water
and, as Reynolds has recently pointed out, it is the only species inhabiting
coasts characterized by great tidal changes. This explains why Blaauw (1916,
491) and others have found it the only common steamer duck in northern and
eastern Tierra del Fuego. It has, furthermore, been collected a number of times
along the Atlantic coast of Patagonia, on the Andean lakes of the pampas in
Chubit. Abbot (1861, 162) describes nests far from the sea in the Falklands,
and Reynolds (1934, 351) reports on others about Lake Yewin and similar bodies
of fresh water in the interior of Tierra del Fuego.
The nesting season seems to be identical with that of the Flightless Steamer
Duck. Oustalet (1891, 229) reports newly hatched young in Beagle Channel
on November 13 and February 1, and states that Picton Island, at the eastern
entrance of this waterway, is a favorite nesting ground. He also reports the
species as common on Staten Island. The eggs often number seven, though eight
or nine have also been reported. Several writers have alleged that eggs can be
distinguished from those of the flightless duck by their shape. However,
Reynolds states definitely in Lowe's account that the eggs of the flightless
species are half again as heavy as those of the flying duck.
The food of the Flying Steamer Duck is in part similar to that of its two
larger relatives, but seems to comprise a smaller proportion of thick-shelled
mollusks, and more prawns, crabs, and other crustaceans.
THE CHARADRIIFORMES
This order includes three great divisions. The suborder Charadrii embraces
ali the snipe-like and plover-like birds; the suborder Lari is made up of the
skuas, gulls, terns, and skimmers; the suborder Alcae, which belongs exclu-
sively to the northern hemisphere, comprises the auks and their kin, all of
which fall outside our field.
In the Charadriine division only three families, namely, the oyster-catchers,
phalaropes, and sheath-bills, are covered by biographies in this book, but many
related shore birds have been referred to under distributional discussion in
Part I. South America, Africa, Australasia, and other southern continental
regions, as well as equally peripheral districts in Polynesia, are rich in endemic
species and genera of the Charadrii. It is likely that many of these are relics
of stocks which originated long ago somewhere in the vast holarctic terrestrial
centers, but which now survive only toward the extremities of the earth's
radiating land areas. The zodgeographic conception is a tested one for other
vertebrates, and is readily understandable if the continental relations are con-
THE CHARADRIIFORMES 973
sidered in north polar projection. The dominant groups of shore birds today,
at any rate, are either holarctic or cosmopolitan, and many species among them
make extremely long annual migrations between the northern and southern
hemispheres, breeding only in the former. The phalaropes, together with
numerous species of snipes and plovers, are examples of this kind. On the other
hand, the oyster-catchers of the southern hemisphere have ‘‘moved in to stay”’
and are relatively sedentary, while the sheath-bills have progressed farther
toward the Antarctic than any other shore birds and have, so to speak, burned
their bridges behind them. They are, indeed, so remote in both systematic and
geographic senses that their relationships are very dubious.
Among the endemic Limicoline types of southern South America are several
forms which appear to be ‘‘structurally ancestral’’ to shore birds of a number of
more widely distributed families. Oreopholus, a primitive plover-like bird of
the Andean plateaus, is a good example. Most of its peculiar relatives in the
same region are likewise inland and montane species rather than birds of the
seacoast. They form a somewhat bizarre aggregation, either with no close kin
elsewhere in the modern world or with relatives confined chiefly to areas toward
the tips of other southern-hemisphere continents and insular extensions; they
include the Painted Snipe (Nycticryphes), such monotypic genera as Ptiloscelys,
Zonibyx, Pluvianellus, and Phegornis, and the strange seed-snipe (Aftagis and
Thinocorus).
An attempt to discuss the relationships of the shore birds as a whole would
be out of place in this text. It is worth pointing out, however, that their
morphology, biology, and distribution still offer a rich field for research,
despite the enormous existing literature pertaining to the members of the
suborder.
The Larine group of the Charadriiformes will be considered below.
THE OYSTER-CATCHERS
FAMILY HAEMATOPODIDAE
The oyster-catchers are a well-marked group of plover-like birds found on
most tropical, temperate, and sub-polar seacoasts throughout the world. They
are absent from Polynesia and from other remote oceanic islands. The northerly
and southerly limits of the family breeding range are, respectively, Iceland and
Cape Horn. Certain Old-World forms follow up the valleys of great river sys-
tems, and are found far inland. In plumage-pattern the birds are either particolor
in large contrasting areas, or wholly dark. Formerly the black or brown oyster-
catchers were specifically distinguished from the pied birds, but Stresemann
(1927, 71) has shown that all but one of the solid-colored forms are mutational
phases of white-breasted oyster-catchers, and are to be regarded as no more
than geographic races of the latter.
Furthermore, the American white-breasted oyster-catchers were formerly
held to belong to a different species (palliatus) from the palaearctic forms
974 OCEANIC BIRDS OF SOUTH AMERICA
Fic. 75. Wing-patterns of three subspecies of Oyster-catchers, to illustrate a character corre-
lated with geographic distribution.
Left, Haematopus ostralegus ostralegus, 9 , Denmark; middle, H. 0. palliatus, 9, South Carolina;
right, H. 0. pitanay, 9, Pisco, Peru.
(ostralegus). These two aggregations have, however, such close affinities in
geographic, taxonomic, and doubtless genetic senses that Stresemann, Peters
(1934, 231), and other authorities now unite them in a single species, the range
of which is very nearly as extensive as that of the entire family. The resem-
blances between the Old- and New-World white-breasted oyster-catchers become
particularly significant when plumage is considered in relation to age, for the
American forms retain as adults essentially the juvenal phase of the Old-World
bird.
I have shown (Murphy, 1925, 3) that the typical subspecies of Europe
(Haematopus ostralegus ostralegus) is characterized by a pattern of white quill-
markings which extends to the shaft of the outermost primary, and that the
oyster-catchers inhabiting more distant regions, both in the Old World and in
America, show progressively reduced quill blotches until, in the peripheral
races of the Australian region and of the west coast of South America, the
primary quills are entirely dark and without spots of any sort. In other words,
if we place the richly marked European Oyster-catcher at the focus of a more or
less concentric series, and proceed eastward and southeastward through and
beyond the palaearctic region, or southwestward across both continents of
America, we find running through the successive races of oyster-catchers a
similar and progressive type of variation, which is correlated with geographic
distribution.
In South America the family is represented by three species, namely, ater,
leucopodus, and ostralegus. Of the last named there are four subspecies, three of
which occupy more or less discontinuous stretches of continental coast, while
the fourth is confined to the Galapagos Islands. Tendency toward the develop-
ment of local races seems to bear a direct ratio to discontinuity of littoral distri-
bution. Perhaps it would be more correct to say that the effect of isolation has
ve OY Ss TER-GCATCHERS 975
thus shown itself in the evolution of distinct races. At any rate, Haematopus
ostralegus, with interrupted ranges on both the east and west coasts of North
and South America, has divided into several subspecies. Haematopus ater, on the
other hand, occupies an unbroken range around Cape Horn and along the
southern Atlantic and Pacific coasts of South America, and specimens from even
widely differing environments appear to be indistinguishable. Haematopus
leucopodus also inhabits a continuous and relatively compact range, near the
southern tip of South America, and seems to have undergone no geographic
subdivision. The South American Black Oyster-catcher (Haematopus ater) is the
most distinct and divergent member of the whole family. Its bill differs so much
from that of other species that even a separate genus has been proposed for this
bird. Its feet are also very large, but the group as a whole shows remarkable
plasticity of foot structure, even within the limits of a single species.
AMERICAN OYSTER-CATCHER
Haematopus ostralegus palliatus
Hamatopus palliatus Temminck, 1820, Man. d’Orn., edit. 2, 2, p. 532 (South America, subsequently restricted
to Venezuela).
The typical form of this species is the oyster-catcher of western Europe, the original citation
of which is:
Hamatopus Ostralegus Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 152 (Oland Island, Sweden, from first reference
in a range stated as Europe and America).
The American race is sufficiently distinct to be described without detailed reference to the
typical race. .
Names: Oyster-catcher, Clam-bird; ‘‘Ostrero’’ is the Spanish name; in northern Brazil the bird
is called “'Pird-pirti,’’ while along the southern Brazilian coast it is known as the ‘'Batuira do
Mar Grosso’’; in some of the Spanish-speaking countries the names ‘‘Pilpilen’’ and *‘Tira-tira’’
are applied either to this oyster-catcher or to closely related subspecies. Synonyms of the specific
or subspecific names include brasiliensis, hypoleuca, and arcticus.
Characters: Rump and lower back grayish brown or black, concolor with back, in which
respect it differs from the white-rumped typical race of Europe; no white on the vanes and shafts
of the outer two or three primaries.
Adults (sexes alike): Head, neck, and upper chest uniform black, with very faint gloss of
bluish green; a white bar or streak immediately beneath lower eyelid; back, scapulars, rump,
median-anterior upper tail coverts, and greater parc of wings plain grayish brown or brownish
gray (nearly hair-brown or deep drab); the sixth and seventh from the outermost primaries have
distal or subterminal white areas, usually 25 mm. or more in length, on the shafts and webs of the
feathers; these are sometimes extensive, wholly crossing the outer web of the feather, and more
rarely the condition, in reduced guise, is observable on the fifth, fourth, or even the third quill;
tips of middle wing coverts (broadly), whole of exposed portion of greater coverts, and proximal
secondaries (next to tertials) immaculate white; distal secondaries deep brownish gray, their
inner webs and basal portion of outer webs white, the outer webs edged with white distally;
primary coverts and primaries dull black or dusky (fuscous black to dark chaetura drab); lateral
and terminal upper tail coverts white, the latter sometimes (rarely) with a few dusky spots or
blotches, the median anterior coverts sometimes margined with white; tail deep brownish gray,
becoming darker (sometimes nearly black) distally, the lateral rectrices with basal half or more
white; under parts of body, including lower chest, axillars, and under wing coverts, immaculate
white, the under primary coverts sometimes more or less broadly tipped with brownish gray, and
the carpo-metacarpal region with more or less of dusky spotting; bill (in life) vermilion-red,
976 OCEANIC BIRDS OF SOUTH AMERICA
deeper (tinged with carmine) in middle portion, the basal portion more orange-red, the tip yel-
lowish; naked eyelids vermilion-red; iris bright yellow; legs and feet very pale flesh color or pinkish
white (modified from Ridgway, 1919, 32).
12 males from Venezuela, Colombia, the Lesser Antilles, Panama, and the southeastern United
States: wing, 237-259 (248.7); tail, 90-104 (97); exposed culmen, 74-89 (82.1); tarsus, 56-64
(59.5); middle toe and claw, 44-50 (46.7) mm.
8 females from Panama and the southeastern United States: wing, 235-271 (258.8); tail, 93-
102 (99.3); exposed culmen, 76-94 (88.2); tarsus, 57-64 (61.4); middle toe and claw, 44-50
(47.5) mm.
Young birds are much like adults, but the bill is brownish, the iris brown, the feet dull livid
grayish, the head and neck dusky, the pileum and cheeks speckled with dull fulvous, the feathers
around the base of bill whitish; furthermore, the upper parts are grayish brown, each feather
rather broadly margined with dull buffy or fulvous.
In the downy chick the head and neck are dull light brownish gray, finely mottled with a
darker hue, and with a narrow post-ocular line of black; the remainder of the dorsal surface is
light buffy gray, with dark mottlings, and relieved by two parallel stripes of black extending
from the upper back to the rump; under parts white.
Eggs: Two or three, more often the latter, and very rarely four. They are ovate to elongate-
ovate in shape and have only a slight gloss. The ground color is usually ‘‘cartridge-buff,’’ some-
times “‘pale olive-buff,”’ and rarely ‘‘deep olive-buff’’ or dull ‘‘chamois."’ They are irregularly
and rather sparingly marked with spots and small blotches, occasionally with a few scrawls of
black, brownish black, or very dark browns, ‘‘mummy brown” or “‘bister,’’ and have underlying
spots in various shades of ‘‘Quaker drab’’ or “‘mouse-gray.'” The measurements of 56 eggs average
55.7 x 38.7 mm.; the eggs showing the four extremes measure 62 x 38.9, 57.2 x 42.2, 51.8 x 39.9,
and 52 x 33.5 mm. (Bent, 1929, 312).
Distribution: Atlantic, Gulf, and Caribbean coasts of North and South America from Virginia
to Brazil or beyond; the West Indies (except the Bahama Islands which have an endemic race);
the Pacific coast of America from the Isthmus of Tehuantepec to Colombia or northern Ecuador,
apparently intergrading in the last-named region with a more southerly subspecies. —
Although records of Oyster-catchers from the West Indies and the northerly
coasts of South America seem to be somewhat rare or indefinite, I have found
either specimens or well-attested citations from Cuba, Haiti, Porto Rico, the
Virgin Islands, Guadeloupe, Aruba Island, Curagao, the Caribbean beaches of
Colombia and Venezuela, and from many localities along the shores of Brazil.
Wetmore (1926, 144) states that on the morning of June 16, 1920, as his steamer
came toward the wharf in the harbor of Rio de Janeiro, seven Oyster-catchers
circled past. Burmeister (1856, 366) writes that the bird is rather common along
the whole eastern coast of South America between the mouths of the Amazon
and the Rio de la Plata. This information gives no clue, however, as to the
boundary between the ranges of the two Atlantic subspecies of South America,
namely palliatus and durnfordi.
In North America the Atlantic range, which formerly extended northward
to the estuary of the River St. Lawrence, has been greatly reduced since the
settlement of the country. The Oyster-catcher is now rare north of Virginia.
No doubt its numbers, if not its range, have been adversely affected in the south-
ern continent as well, for it nowhere appears to have maintained the abundance
of former times, and has become in many places a relatively scarce bird.
At the Isthmus of Panama, the range of the Atlantic race of the Oyster-
catcher breaks through, so to speak, to the Pacific. Along this western coast it
AMERICAN OYSTER-CATCHER 977
then spreads northward as far as Mexico, and southward to an undetermined
point in Colombia or northern Ecuador. Rendah] (1920, 24) found this sub-
species common on the islands of Bayoneta and San Miguel, of the Pearl Island
group, in the Gulf of Panama. He observed in one of his specimens a reduction
of the white markings on the proximal primaries. This, in conjunction with
related evidence, is significant as indicating an intergradation with the race
occupying the arid coast between Point Santa Elena, Ecuador, and south-central
Chile. A further note on the subject will be found in the account of the west
coast form (CH. o. pitanay).
In the absence of specimens, it is impossible to fix the identity of Oyster-
catchers recorded from southern Brazil and Uruguay. Further collecting may
prove, moreover, that the Oyster-catcher of the eastern United States is sub-
specifically separable from that of northeastern South America. The former,
upon the basis of the series compared, averages very slightly larger, the white
chin (not mentioned by Ridgway) is conspicuous only among North American
examples, and the white markings on the shafts and outer webs of the primaries
extend, on the average, farther toward the outer border of the wing. All of
these differences, however, appear not to exceed the range of individual varia-
tion among birds from one locality. Examples from Venezuela and Colombia
are essentially topotypes, and these agree well with others from Texas, the
Pearl Islands, and the eastern seacoast of the United States.
While accepting Peters’s (1934, 231) classification of the American white-
breasted oyster-catchers as subspecies of the Old-World form, it is only fair to
point out that the American races resemble one another more than they do the
typical race of Europe. We may, therefore, speak of the several American
subspecies as the ‘‘palliatus’’ group of the species.
The following résumé of the life history of the Atlantic White-breasted
Oyster-catcher is based largely upon the report of Bent (1929, 309), and refers in
the main to observations made in the southeastern United States.
The usual impression of this large and showy wader is a fleeting glimpse of
a black and white bird disappearing in the distance over hot, shimmering sands.
It is one of the shyest and wildest of our shore birds, seeming ever on the alert
to escape danger. Even during the breeding season, when anxiety for its eggs
or young prompts it to be less wary, it flies around the intruder in wide circles,
well beyond gun range, yelling its loud notes of protest. It was evidently about
as shy even in the days of Audubon and Wilson, for both mentioned its wariness.
White-breasted Oyster-catchers prefer broad sandy beaches to rocky or
shingly coasts. They therefore commonly consort with various little plovers
and other beach birds. The latter, however, are more or less protectively colored,
while the Oyster-catcher is not only large but is most conspicuously garbed.
The nests are usually on the higher parts of sandy beaches, well above normal
high watermark. The site is often on a slight mound, which gives the watchful
birds a lookout. The nest itself is generally a mere hollow without lining, but
in some instances it may be paved with a mosaic of shell fragments. Nests would
be difficult to find but for the noisiness of the parent birds and the fact that
978 OCEANIC BIRDS OF SOUTH AMERICA
innumerable rather heavy, three-toed footprints are likely to point toward
them from all directions. An incubating bird has been observed to carry off
the eggs between its legs, and to deposit them one after another in a new site,
while the original nest was under observation. Usually one pair of breeding
birds seems to require and dominate a good-sized strip of territory, though
occasionally nests have been found rather close together. The period of incuba-
tion for the European Oyster-catcher has been determined as from 21 to 24 days,
and doubtless that of the American bird is not materially different. While both
sexes cover the egg, the greater share is taken by the female. Very soon after
the young hatch they are able to run so rapidly that it is difficult to catch them.
At a note of warning from their watchful parents they “‘freeze,’’ upon which
their obliterative coloration makes them practically invisible.
During the non-breeding season Oyster-catchers are inclined to be gregarious,
and often form flocks containing well toward a hundred individuals. Such
bodies of birds like to fly back of the beaches to fresh-water ponds where they
may drink and bathe, although they seem rarely to go far from the sea. Such
birds appear perfectly aware of their conspicuousness, making no attempt at
concealment but usually take the precaution to keep well out of gunshot. They
pay no attention to decoys of any sort. They are excellent swimmers and can
dive when necessary.
Forbush (1928, 48) reports watching Oyster-catchers disabling the small
‘coon’ oysters with a single clip of the powerful bill. These mollusks are
exposed at low tide along the bars of Florida, and the birds know how to open
them as well as any professional oysterman. They feast upon the bivalves until
their flesh veritably acquires the flavor of an oyster. They not only knock or
pry shellfish off rocks and mangrove roots, but also probe deeply for them in the
sand. Items of their food include many other kinds of bivalves and gastropods,
such as clams, mussels and limpets, as well as marine worms, shrimps and other
crustaceans, and many insects.
PERUVIAN OYSTER-CATCHER
Haematopus ostralegus pitanay
Haematopus palliatus pitanay Murphy, 1925, Amer. Mus. Novit. No. 194, p. 1 (Pisco Bay, Peru).
Names: The commonest Peruvian name is ‘‘Brujillo de Pecho Blanco,”’ or ‘‘white-breasted
wizard"; ‘'Pitanay”’ is another vernacular name, of Indian origin; ‘‘Pilpilen’’ or ‘’Pipilen,’’ and
“Tira-tira,'’ are among the names used in Chile.
Characters: Differs from H. o. palliatus in its smaller size (smallest race of the American group
in all dimensions except length of bill), and in the great reduction or, more frequently, the com-
plete elimination, of white subterminal shaft-markings and of a pattern of clear white blotches on
the inner primary quills. The flesh colors are like those of the preceding form and of the other
American subspecies. Lane (1897, 303) particularly describes the bill of a Chilean example as
“‘poppy-red at base, merging into carmine, which assumes a bright transparent yellowish hue
at the tip.”
A specimen taken at the Chincha Islands, Peru, weighed 794 grams (Coker, 1919, 496).
9 males from Ecuador, Peru, and Chile: wing, 232-250 (240.2); tail, 91-100 (95.5); exposed
culmen, 72-83.5 (76.4); tarsus, 51-57 (53.9); middle toe and claw, 37-42 (40.5) mm.
PERUVIAN OYSTER-CATCHER 979
6 females from Ecuador, Peru, and Chile: wing, 239-270 (247.6); tail, 91-103 (95.6); exposed
culmen, 77-87 (82.3); tarsus, 54-60 (56.5); middle toe and claw, 39-44 (41.1) mm.
Distribution: Pacific coast of South America from western Ecuador southward to Chiloé
Island, Chile.
Comparison of about a score of birds of this race with other oyster-catchers
indicates that in most dimensions it is the smallest of the American or ‘‘pallia-
tus’ group.
Chilean and Peruvian specimens show no trace of white upon the shafts and
webs of the primaries. Among four birds from the neighborhood of the Gulf of
Guayaquil, Ecuador, however, two have a mottled whitish patch on the outer
web of the seventh primary, unaccompanied by white shaft-markings. Such
examples are, to this extent, intermediate between pitanay and palliatus. It
thus appears that evidence of intergradation turns up along the humid Pacific
coast of northern South America, between the Pearl Islands (cf. note on p. 977)
and the beginning of the desert shore.
The northern limit of the range of this subspecies, as represented by typical
examples, is doubtless in western Ecuador, where the arid coast begins to be
interrupted by patches of rain forest. I have collected specimens at Point Santa
Elena in February, and others have been taken or observed during American
Museum Expeditions at Puna, Tembleque, and Jambeli Islands, in the Gulf of
Guayaquil, during July (Chapman, 1926, 190). From this region the range of
the subspecies extends southward to, and slightly beyond, the other end of the
rainless zone, in Chile. This Oyster-catcher is therefore one of a number of
endemic birds which make up part of the distinctive shore fauna of the Hum-
boldt Current zone. In view of the extreme aridity characterizing nine-tenths
of its range, it is interesting to note that pitanay is not a ‘‘pale’’ race, but that,
on the contrary, the brown of its dorsal surface is definitely, though only
slightly, darker than that of the Atlantic-Caribbean-Isthmian subspecies
palliatus.
Chilean records of this Oyster-catcher are now numerous enough to indicate
the extreme southerly border of the range. It occurs along the beaches of Arauco
(Lane, 1897, 303), and Mr. D. S. Bullock has recently sent the Museum an
adult female taken at Mocha Island on December 8, 1932. His manuscript notes
state that these birds are common all around the shores of the island, breeding
during November and December, but that in winter they migrate northward.
Sclater and Salvin (1870, 499) have long since recorded this Oyster-catcher from
Chiloé, and Hellmayr (1932, 382) finds that specimens from: that island are
typical of the subspecies pétanay. Here, at the southern limit of the range, it was
found by an expedition of the Field Museum of Natural History, nesting during
December and January with two other species of oyster-catchers, H. ater and
H. leucopodus.
Throughout what may perhaps be called the optimum portion of the range
of the subspecies, that is, along the desert coast of Peru and northern Chile,
observations of this Oyster-catcher are too numerous to cite. Among the locali-
ties represented by specimens are Lobos de Tierra Island, Ancén, Asia Island,
980 OCEANIC BIRDS OF SOUTH AMERICA
Pisco Bay (mainland and islands), San Gallan Island, San Juan Bay, Indepen-
dencia Bay, Tarapaca, etc. Along such coasts the White-breasted Oyster-
catcher is a bird of broad sandy beaches. It leaves the rocky stretches mostly to
its congener the Black Oyster-catcher (Haematopus ater), so that the habitats of
the two species alternate instead of coincide. The sheltered, southerly or
windward ends of a number of bays in Peru, such as the great cove of Paracas in
Pisco Bay, and the mainland shores of Independencia Bay, are lined with long
reaches of beautiful flat strand, and here the ‘‘Pitanayes’’ feed with flocks of
plovers, sandpipers, curlews, and Gray Gulls (Larus modestus), greedily devour-
ing the sand crustaceans which the Peruvians call “‘mui-muis"’ (Emerita), and
occasionally making loud, delirious music as they circle over the water to
alight farther up the beach.
Because of their preference for such smooth beaches, these Oyster-catchers are
more characteristic of the mainland than of the guano islands. Only a few of the
latter have strands more than a stone's throw in length, and the ‘’Brujillo
Negro,”’ rather than the white-breasted species, is the common insular form.
On the rocky coast of San Gallan Island I recorded one Pitanay on November
26, 1919, but it was evidently only a transient for it was not seen again, while
the black birds were numerous and breeding.
Coker (1919, 195) writes as follows of this bird, which he frequently en-
countered during his field work along the coast of Peru:
With its distinctive cry and striking color markings, the white-breast brujillo is unmistakable,
whether in the air or on the land. In flight the conspicuous white band on the upper surface of the
wing, the white breast, the almost black head, and bright red bill directed downward and con-
tinually opening and closing, make this bird as conspicuous as does its shrill excited cry. While on
the ground they usually make a single isolated call, but when flying high-pitched cries are uttered
almost incessantly. On one occasion, in the little Bay of Chilca, about a dozen of these birds in a
group on the shore, becoming excited from some cause, fairly filled the small amphitheater with
their shrill voices. This was an unusual aggregation, for I rarely observed them except in pairs,
whether at rest or in flight.
The nest and eggs of this Oyster-catcher have apparently not been described.
Germain (1860, 314) says merely that in central Chile it lays two or three eggs
near the sea during October or November. Bullock, however, has recently
found nests on Mocha Island, and has sent a photograph to the American Mu-
seum, along with the skin of an adult bird. The nests were among sparse
vegetation just above high tide line. Sets of two fresh eggs were taken on
November 28 and December 2, 1932. A female bird examined by Coker at the
Chincha Islands, Peru, in June, had only very minute eggs in the ovary. In
another, taken in late August, the ova were three to four millimeters in diameter.
It seems probable that throughout the range this Oyster-catcher breeds only
during the southern-hemisphere spring.
The stomachs of two of my own specimens collected along the central part
of the Peruvian coast contained animal matter and gravel. The former included
in one instance 97 per cent of ground-up marine worms (Polychaeta), 2 per cent
of bits of a bivalve (Thais or Concholepas), and 1 per cent of barnacles (Balanus
laevis). The other stomach contained practically 100 per cent of triturated hippas
PERUVIAN OYSTER-CATCHER 981
(Emerita analoga) and traces of a crab (Plagiusa chabrus). The determinations
were made at the United States Biological Survey. Coker found small pebbles,
bits of crustaceans, opercula and shell fragments of gastropods, and mussel
shells in the Peruvian birds he examined.
GALAPAGOS OYSTER-CATCHER
Haematopus ostralegus galapagensis
Haematopus galapagensis Ridgway, 1886, Auk, 3, p. 331 (Chatham Island, Galapagos).
Names: The Galapagos race has been listed in the earlier literature under the specific name
palliatus.
Characters: Differs from the two preceding races in having a darker coloration dorsally, heavier
mottling on the breast along the junction of black and white plumage, and notably large feet.
2 males: wing, 250-254 (252); tail, 96-104 (100); exposed culmen, 80-86.5 (83.2); tarsus,
54-55 (54.5); middle toe and claw, 49 mm.
4 females: wing, 250-256 (252); tail, 91-96 (92.7); exposed culmen, 80-88 (84.2); tarsus,
53-57 (55.2); middle toe and claw, 48-51 (49.5) mm. ;
Distribution: The greater part of the Galapagos Archipelago, though not reported thus far
from the outlying northern islands, Culpepper and Wenman (Swarth, 1931, 57).
In this race we find the maximum of pigment saturation within the *‘pallia-
tus’ group, combined with total lack of a white pattern on the primary quills,
and extraordinarily long toes. The heavy mottling of the breast is also charac-
teristic of the Lower Californian subspecies (frazari) and the Patagonian sub-
species (durnfordi), but not, as a rule, of the subspecies palliatus and pitanay.
However, this feature is evidently carried by a gene common to the American
white-breasted group as a whole, because it crops out sporadically among
Oyster-catchers from the eastern United States and elsewhere. Gifford (1926,
49) states that among young Galapagos birds this line of demarcation is sharp,
while in adults it is highly irregular.
The Galapagos form is apparently closest to that of Lower California.
Swarth (1931, 58) writes that this resemblance is
. of note, considering how meager are the indications in the Galapagos avifauna of affinities
toward the west coast of North America. Murphy (1925, pp. 6, 11) points out that the Atlantic
form of the Oystercatcher (palliatus) crosses to the Pacific side in the Panama region, as indicated
by the white-marked primaries of birds from that section, and considering the strong West Indian
complexion borne by the aquatic avifauna of the Galapagos it might well have been predicted that
the Oystercatcher, too, would be of the Atlantic strain. The fact remains that in the Galapagos
birds the primaries bear no white marks along the quills, and that they are closely similar to the
Lower California form.
Snodgrass and Heller (1904, 262) found the Oyster-catchers nearly every-
where along the shores of the Galapagos, though nowhere abundant. On the
western side of South Seymour Island the birds seemed to concentrate at times
in pools just back of the shore. They were always tame, a fact confirmed by
Beebe (1924, 109), who states that the Oyster-catchers not only cackled with
anticipation whenever the seine was drawn at Indefatigable Island, but would
also run between the legs of a motion picture camera tripod while the photog-
982 OCEANIC BIRDS OF SOUTH AMERICA
rapher was grinding. Their tameness resembled that of other native Galapagos
birds, but set them sharply apart from the reactions of such migrants as turn-
stones, with which the Oyster-catchers associated.
The nest and eggs of the Galapagos Oyster-catcher seem never to have been
described. The not quite conclusive notes of Rothschild and Hartert (1902,
412) indicate that the very dark pigmentation of this race is shared by the
downy young. Older chicks appear to resemble similar stages in the other
American races (Gifford, 1926, 48). Gifford also presents evidence that the
adults moult their flight feathers twice a year. His notes suggest that the
breeding season of this form probably comes, like that of Peruvian and
Chilean Oyster-catchers, between September and January. This, however, will
require confirmation.
The fullest account of the Galapagos Oyster-catcher is that of Gifford, by
whom the race was observed in 1905-1906, during the expedition of the Cali-
fornia Academy of Sciences. He writes that the birds were evenly distributed on
twelve or more islands which he names, but rarely were more than three or four
individuals seen at one time.
Singly or in pairs, we met with them along the rocky coasts, where they did most of their
feeding. Occasionally they were seen on the sandy beaches, which are quite extensive on the larger
islands. As a rule they were very fearless, and several were killed with stones.
In traveling over the smooth beaches this species either walks or runs, being able in the latter
case to travel quite rapidly. One day on South Seymour two kept just ahead of us for about one
hundred yards along a beach, running slowly all the time. When anchoring at James Bay, James
Island, on August 6, three flew by the vessel, and later we met them on the beach. They alighted a
hundred yards or so above us, and then started on the run in our direction. They acted as though
they were racing, keeping abreast most of the time, and maintaining a steady pace. When among
the rocks, these birds do considerable jumping from one rock to another, often using their wings
to aid them.
Their flight is nothing like that of a snipe for swiftness and gracefulness, nor is it as erratic
as the Hudsonian Curlew’s. Usually, when over the water, the birds fly at a height of ten or twenty
feet, while along the shores they keep lower down. Their wing-beats are more rapid than a gull's.
On two occasions this species was observed swimming, but not through choice. In one case
a wounded one took to the water, and, upon being approached with the boat, dived three or
four times. . . .
Aside from one instance, these oyster-catchers are always noted feeding on the rocks from which
they pick their food. The food consists of small chitons, small crabs, sea-slugs, and key-hole
limpets, which are chiefly obtainable at low tide. These creatures are all swallowed whole.
Many times the presence of this species is made known, not by the eye, but by the ear. Asa
rule they call when disturbed, and when flying from place to place. The call is loud and piercing,
and consists of a series of piping notes given in quick succession, and slightly resembles the call of
the Wandering Tattler. Single short staccato notes are also uttered when a bird is approached.
Three specimens, which showed signs of breeding, were taken on Gardner-near-Hood on Sep-
tember 28, 1905. Sexual organs of birds taken at Sappho Cove, Chatham, February 14, and at
Academy Bay, Indefatigable Island, July 16, were small. A female with medium-sized ovaries
was taken on Narborough on Match 22.
On February 1, two young ones scarcely able to fly were taken on southeast Hood. They were
feeding in company with two adult birds, presumably their parents. On March 22 a young one of
about the same age was taken on Narborough. Another was taken on South Seymour on July 26,
and still another on northeast James on August 4.
While I was approaching a wounded one on northwest Indefatigable, one of several Galapagos
GALAPAGOS OYSTER-CATCHER 983
Hawks roosting in the vicinity made a sudden swoop at it. Uttering a shrill cry, the oyster-
catcher sought safety by jumping into the water close beside a sheltering rock. It is doubtful
whether the oyster-catchers are harassed by the hawks under normal conditions.
Like the Wandering Tattler, but not to such a great extent, this species has the habit of bobbing
the posterior portion of the body up and down.
One bird taken had the outer covering of the upper mandible loose and apparently ready to
shed, for it was very easily detached, leaving a new, hard, and darker-colored bill beneath. Another
specimen was minus the greater part of its tongue, having only about one quarter of an inch of it left.
PATAGONIAN OYSTER-CATCHER
Haematopus ostralegus durnfordi
Hamatopus durnfordi Sharpe, 1896, Cat. Birds Brit. Mus., 24, p. 107 (in key), p. 117, pl. 6 (Tombo Point,
latitude 44° 06’ S., coast of Patagonia).
Names: In Argentina, ‘‘Teru de la Costa,’’ to distinguish it from the inland ‘‘Teru,"’ or lap-
wing. Early references to this Oyster-catcher are listed under the specific name palliatus.
Characters: Very unsatisfactorily known. Specimens have white-marked primaries, similar
to those of H. 0. palliatus taken on the Atlantic coast of tropical South America. In the heavily
mottled line of demarcation between black and white plumage on the breast, however, this race
differs from palliatus, and bears a close resemblance to H. o. galapagensis. The general superficial
likeness of Patagonian to Galapagos birds is, in fact, strongly marked, although the former lack
the hypertrophied feet of the latter. Murphy (1925, 7) has shown that many of the characters
ascribed to the type of durnfordi, or to examples subsequently studied, are untenable, and that the
subspecies stands in need of adequate characterization.
An adult female shot in the province of Buenos Aires on November 3, during the courtship
season, had the center of the bill between scarlet and jasper-red, shading at the base to a color
between bittersweet-orange and flame-scarlet, and at the extreme tip to antimony-yellow; bare
eyelids slightly darker than orange-chrome; iris cadmium-yellow; tarsus and toes cartridge-buff;
nails buff (Wetmore, 1926, 145).
3 males: wing, 244-253 (247.3); tail, 92-100 (97); exposed culmen, 71-79 (76); tarsus, 52-
56 (53.7); middle toe and claw, 42-44 (43) mm.
3 females: wing, 245-255 (250); tail, 94-100 (97.3); exposed culmen, 76-90 (82.3); tarsus,
54-58 (56); middle toe and claw, 42-44 (43) mm.
Of the eggs, Gibson (1920, 61) writes that they are very handsome, and if from their protective
coloration not particularly distinguishable in situ, show up prominently in a cabinet. The ground
color is either of a pale yellow or warm buff, marked with purplish spots and large, bold, dark
brown or black blotches with some streaks of the same; below the surface there are occasionally a
few smaller pale mauve spots and markings. They are of an oval-pointed shape, and average
55 x 37 mm.
Distribution: Atlantic coast of southern South America, from Uruguay or southern Brazil Q)
southward at least to the Province of Chubut, Argentina.
The type of this Oyster-catcher came from Tombo Point, Patagonia, but the
collector, Durnford (1878, 403), states that it is also a common bird about the
mouth of the Rio Chubiat, a little to northward of the type locality. From this
part of the Patagonian coast I have seen no specimens, but six birds from more
northerly Argentina, namely from Lavalle and Cape San Antonio in the Province
of Buenos Aires, represent a subspecies of Oyster-catcher distinct from that of
the northern Atlantic coast of South America. Since the outstanding charac-
teristic of these specimens is a general superficial resemblance to birds of the
Galapagos race, a matter stressed by Sharpe (1896, 117), they probably repre-
sent the form which occupies the Atlantic coast from some unknown point in
984 OCEANIC BIRDS OF SOUTH AMERICA
Uruguay or southern Brazil southward to the limit in range of the species
ostralegus, which is perhaps in the neighborhood of the Gulf of San Jorge,
Patagonia. Although this southerly extremity has not yet been determined, it
lies, no doubt, well to northward of the Magellanic humid zone, in which
H. leucopodus replaces the nearly cosmopolitan white-breasted species, ostralegus.
If the assumed range is correct, H. 0. durnfordi is the subspecies of Oyster-
catcher collected by Darwin on the shores of the Rio de la Plata (Gould, 1841,
128), and since then reported upon by Gibson (1920, 60), Wetmore (1926, 144),
and others.
Gibson writes that this Oyster-catcher is the principal resident of the lonely
Atlantic seacoast to southward of Cape San Antonio. It is scarcely less at home
in the salt lagoons of the Rincones, which lie to westward of the Cape, 2. e. on
the Rio de la Plata side, and also among the “‘cangrejales’’ of the same region.
During flood seasons, such as occurred here between 1913 and 1915, with large
areas running to fresh water, the Oyster-catchers totally abandoned the whole
shore of the Plata estuary, and betook themselves to the outer seacoast.
These birds, continues Gibson, are always found in pairs. They are not
particularly shy, and their loud, clear notes are frequently heard while they
are on the wing. They are relatively late breeders among resident beach birds
along the outer coast of Buenos Aires, the usual season being between early
December and the middle of January, although Gibson once took a young chick
as early as December 8. The nest is a mere scrape among shells and jetsam,
usually some distance above high watermark, and often on a slight rise of
ground from where the sitting bird can dominate all parts of the outlook except
the sand dunes behind. For such reasons the nests are most readily found when
an observer approaches from an inland direction. The eggs never exceed two in
number, and Gibson has found single well-incubated eggs, or single chicks in a
family, to be not uncommon.
Wetmore (1926, 144) extends Gibson's observations by the following inter-
esting notes made between eastern Argentina and the Uruguayan shore of the
Rio de la Plata. He first encountered the birds on mudbanks at the mouth of
the Rio Ajo, below Lavalle, on October 25, and early in the next month found
them fairly common on the broad strand southward of Cape San Antonio.
Here oyster catchers in pairs fed in the shallow sweep of the surf, often where waves of more
momentum than usual came nearly to their bodies. The birds walked slowly, with necks drawn
in and heads inclined forward, seldom extending the neck to full length unless on the wing. Their
flight was swift and direct, usually only a few feet above the sand, but not infrequently, to avoid
me, in a semicircle that carried them over the dunes or out over the sea.
They were difficult to kill at any great distance because of their dense plumage and heavily
muscled bodies. A female and two males were shot on November 3, and a second female on the day
that followed. The nesting season was about at hand, and it is probable that some had eggs at
that season, as females shot were nearly ready to lay. One male in mating ardor pursued a female
in swift flight that carried them turning and dodging over the dunes along the beach until the birds
were lost to sight. On November 15, at the mouth of the Rio Ajo again, where several oyster
catchers were seen, one pair had a nest somewhere on a small strip of sandy beach. I hid behind a
clump of grass and watched from a distance, but though the birds returned in a short time, I failed
to locate either eggs or young.
PATAGONIAN OYSTER-CATCHER 985
At Ingeniero White, on December 13, an oyster catcher was eating small crabs that it pursued
quickly across the mud or secured by pulling them out of holes sunk in the clay. Four oyster
catchers were recorded on the coast near Montevideo, Uruguay, on January 16, 1921, and several
noted on the sandy beach at La Paloma, Rocha, on January 23, may have had young, as they
circled past me with shrill whistles.
FUEGIAN OYSTER-CATCHER
Haematopus leucopodus
Hamatopus leucopodus Garnot, 1826, Ann. Sci. Nat., 7, p. 47 (Falkland Islands).
Names: Pied Oyster-catcher; Black and White Curlew, in the Falkland Islands; ‘‘Ostrero
Overo"’ is one of the Spanish names, distinguishing the species from the ‘‘Ostrero Negro"’ or Black
Oyster-catcher. Synonyms of the specific name include /eucopus, luctuosus, arcticus, and bicolor.
Characters: A slender-billed, black and white oyster-catcher, the back and scapulars being deep
blue-black like the head and neck, instead of brown; breast uniform blue-black; feet extremely small.
Adults (sexes alike): Head, neck, mantle, lower back, and rump glossy black, except for a
small crescentic white spot below the eye; breast black like the neck, with a sharp line of demarca-
tion where it meets the white plumage of the ventral surface of the body; primary quills black with
no white along the shafts or webs; secondaries, except two or three of the innermost, white, their
coverts black with broad white terminations; remainder of upper wing coverts glossy black; under
wing coverts black, the axillaries white; rectrices terminally glossy black, their basal halves white,
the shafts agreeing in color in each area; upper and under tail coverts white. Iris brilliant yellow—
Fuegian examples, carefully examined in the flesh, all had a black spot, in the form of a crescent
moon, in the yellow iris beneath the pupil (Reynolds, 1934, 352); eyelid yellow; bill red, scarlet,
or orange-red (blackish for the distal two-thirds of its length in young birds); feet white or faintly
rosy (flesh colored or grayish in younger birds). The iris is brown in chicks, changing to yellowish
and then to clear yellow as the birds mature.
19 males: wing, 237-259 (251.9); tail, 94-108 (101.6); exposed culmen, 68-76 (73.2); tarsus,
46.5-49 (47.5); middle toe and claw, 37.5-40 (39.1) mm.
11 females: wing, 244-260 (251.5); tail, 93-106 (98.8); exposed culmen, 72-85 (79); tarsus,
43-51 (48.3); middle toe with claw, 37-41 (39.1) mm.
Chicks have a plover- and tern-like plumage above, but the pattern of white under parts is
like that of old birds. From the down they moult into a plumage which differs from that of the
adults in that the dark parts are brownish black instead of a rich green-black or blue-black. In
fresh juvenal plumage, moreover, the dark feathers of the upper surface have rufous edgings, and
those of the breast faint white edgings.
Judging from a juvenal taken at Rio Gallegos, August 27, 1915, the first plumage is worn
through the first year, new feathers being acquired just before the breeding season.
Two sets of eggs taken by Beck in East Falkland are in clutches of one and two, respectively.
They represent both typical ovate and elongate-ovate forms, have much darker ground color than
those of the Black Oyster-catcher of the same region (Haematopus ater), and the markings are
chiefly made up of larger surface and sub-surface spots, with more of a tendency toward concentra-
tion about the large end. The ground color is of an olive-gray hue, the surface blotches dark brown.
The single egg constituting one set measures 62 x 39.7 mm., the two of the other set 58 x 41.3 and
58.3 x 41.1 mm. Descriptions by Vallentin (1924, 308) and others agree, except that some examples
of eggs are said to be evenly marked with brown or blackish spots and blotches over their entire sur-
face. A series of 19 recorded by Vallentin measured 59-63 mm. in length by 42-43 mm. in breadth.
Distribution: Chiefly the Magellanic humid zone, but somewhat farther northward along the
Patagonian coast; from the Rio Chubut, Argentina, southward to the Falklands, Tierra del Fuego
and Staten Island, and northward along the Pacific coast to Chiloé Island, Chile.
At the Falkland Islands, the type locality of this handsome Oyster-catcher,
it is known as the Black and White Curlew. Asa matter of fact, its long-drawn
wailing cry, which sometimes sounds extremely melancholy as it rings across
986 OCEANIC BIRDS OF SOUTH AMERICA
the moorlands, very much resembles that of the true Curlew in the British Isles.
It is shrill and ear-piercing at close range, but plaintive and silvery when heard
at a distance. This call is quite different from the steely, rapid-fire note of
alarm often uttered. The latter is entirely “‘oyster-catcher-like’’ and when
seventy or eighty of the birds are flushed while feeding together, they can make
an amazing amount of noise.
Cobb (1910, 71; 1933, 26), from whose accounts most of the foregoing is
drawn, has given the best life-history notes on this Oyster-catcher at the Falk-
lands. His description of the smart and dainty bird, with its coral-red bill, pale
flesh-colored legs and feet, and striking plumage-pattern, running along scream-
ing incessantly, its bill almost touching the ground and its tail erected vertically
so as to show the white fan beneath, is a vivid one. Crawshay (1907, 123) also
speaks of its pugnacity. As one rides or walks in Tierra del Fuego, he says, the
Pied Oyster-catchers are forever flying forth, making one raise one's hand in
defense against the formidable-looking scarlet bill. After tilting in this fashion
they circle around, skim the grass, and come at one again. On the ground they
often assume a curious posture, with the back to the wind, the neck stretched
out, and the tail blown over the head.
In moments of composure the Fuegian Oyster-catcher may rest upon one leg,
with the bill turned back under the wing coverts but with one golden eye kept
open for the slightest movement of a watcher, which will send it off again and
bring forth a new tirade. The birds spend much time preening and invariably
look well-groomed. When they are angry they point their wings straight up-
ward and hold them there in the proud manner of skuas. During their breeding
season their wideawakeness is redoubled. They then seem, says Cobb,
. to be everlastingly on edge and as ready to resent intrusion from Sea Hens, hawks, or gulls
as from human beings. By all their noisy agitation, however, they frequently show where the
eggs are, whereas silent behaviour on their part would probably leave them unnoticed, as the
blotched, protective colourings on these eggs often harmonise with their surroundings. As it is,
they play a regular game like a children’s game of “‘hot and cold"’; the nearer one gets to their
eggs, the more noise they make, and vice versa.
The range of this Oyster-catcher evidently begins on the Patagonian coast
close to the point at which that of Haematopus ostralegus durnfordi ends. Doubt-
less the two species overlap slightly, as they do also at the northern limit of
the range of leucopodus on the west coast of South America, viz. at Chiloé Island.
From these districts on the Atlantic and Pacific coasts, respectively, the Pied
Oyster-catcher occurs southward to Cape Horn, including within its range all
the complicated waterways of the Magellanic region. Throughout Tierra del
Fuego it is, in fact, a much more common bird than the Black Oyster-catcher,
and is likewise less confined in its local distribution to the edge of salt water.
It is to be found scarcely less in the inland lagoons and upon extensive grass
flats, meadows, and semi-desert stretches. Scott and Sharpe (1910, 270) report
examples from Lake Blanco in the province of Chubut. In such respects it seems
to bear a closer relation in habit to the European Oyster-catcher than do any
of the American members of the species ostralegus.
FUEGIAN OYSTER-CATCHER 987
References indicating the wide distribution of this Oyster-catcher are very
numerous, and they tend to show that migratory movements are slight and
indefinite, and that the species holds its ground even during the winter at the
southern extremity of its range. Crawshay (1907, 123) tells us that in Tierra
del Fuego the only notable difference in seasonal distribution is that the birds
tend to cling to the seacoast in winter, while in spring and summer, when their
piping calls are the bird notes that usher in the dawn, they disperse over large
areas of snow-free land. After the end of the breeding season, they once more
assemble in flocks and become beach combers.
Oustalet (1891, 121), Salvadori (1906, 25), Paessler (1909, 103), and Murphy
(1925, 11) record the Fuegian Oyster-catcher from a large number of localities in
Staten Island, Tierra del Fuego, and among the islets to southward and west-
ward, at all seasons of the year. Reynolds (1934, 352) not only describes the
recent nesting of a pair at the Isla de los Conejos, in Beagle Channel, but tells
also of seeing a bird of the species flying across the mountains of Tierra del
Fuego, between Bahia Moat and the Atlantic coast. He noted this errant
individual by chance, when a gunshot among the hills north of the eastern end
of Beagle Channel was answered by the loud cry of an “‘Ostrero’’ from the air
between cloud-enveloped peaks.
On the Brewster-Sanford Expedition Mr. Beck saw much of the Fuegian
Oyster-catcher during his long wanderings in southern South America. He col-
lected specimens at various localities in the Falklands, at the mouth of the Rio
Gallegos in Patagonia, in the Strait of Magellan and Beagle Channel, at Cape
Horn, False Cape Horn, Grande, London, O’Brien, Navarino, Bertrand, Tim-
bales, and Caroline Islands. All of his specimens, and every other I have ex-
amined, represent a single race which exhibits much individual variation as
regards dimensions. Thus two adult breeding females taken on the same day at
Timbales Island, Chile, have bills measuring 72 and 83.5 millimeters, respec-
tively. This is greater than any observable variation which might be attributed
to geographical grounds. A female from Caroline Island has a bill 85 milli-
meters in length, the longest found in either sex. Ridgway's (1919, 29) key
character, ‘‘depth of bill less than 10 mm.,’’ proves not to hold, although the
species has, indeed, a strikingly slender bill. Furthermore, it is characterized
by remarkably short, stubby toes and broad nails. In these respects it differs
from the black species, and somewhat less than the “‘palliatus’’ group. It has
a particularly wide flange on all three claws. Except for the absence of the hind
toe, the feet closely resemble those of sheath-bills.
Beck's journal abounds in scattered references to this Oyster-catcher. During
July, or midwinter, of 1914, he observed that flocks of hundreds were accustomed
to fly in early morning across the Strait of Magellan from near Magallanes, in
order to feed on the flats of Tierra del Fuego throughout the day. Toward dusk
they would all return to rest for the night on the gravelly beach of Punta Arenas.
At Rio Gallegos, during the latter part of May, 1915, he observed large numbers
every day, during the hours of receding tide, working across the extensive mud
flats to feed upon the small clams and mussels which were abundant in certain
988 OCEANIC BIRDS OF SOUTH AMERICA
patches. This custom evidently increases with the advance of southern-hemi-
sphere winter, for on August 19 of the same year Beck followed across the flats
of Rio Gallegos a flock of Pied Oyster-catchers which he estimated to number
not less than four thousand. When the flood rushes in, such birds rest and nap
in full-bellied contentment.
According to Cobb (1933, 26), the Fuegian Oyster-catcher begins to nest
earlier in the year than the Black Oyster-catcher, mating in the Falklands during
September and sometimes laying eggs before the end of that month. This is
confirmed by Beck's capture of downy young at the Falklands early in Novem-
ber. On the other hand, Vallentin (1924, 308) states that eggs are commonest
during the first part of November, and Beck found on East Island two nests
with eggs as late as December 10, 1915. In these instances, the nests were only
a few steps from those of Kelp Gulls. Nearer the southern tip of South America,
namely at Isla Grande, Beck collected in December females which had obviously
not yet laid their eggs. The nesting season is perhaps a relatively long one, with-
out close synchronization among the population as a whole, or it may be that
accidents to an early set of eggs account for some of the later breeding records.
The nests and eggs of the Fuegian Oyster-catcher have been described by
many observers. McCormick (1884, 328) refers to a nest with two eggs on the
banks of an arm of Berkeley Sound, Falkland Islands, which he found on
November 22. This was on dry seaweed just above high watermark, but one
would infer from the author's remarks that this species commonly nests farther
back from the open beaches than does the Black Oyster-catcher. Crawshay
(1907, 124) states that this is true for at least some of the birds in Tierra del
Fuego, where they breed commonly on open grass flats. Several times he found
nests on slightly raised hillocks which cover much of the lower terrain in
that region.
Cobb states that in the Falklands the eggs are sometimes laid among beach
pebbles without any attempt at nest-making, while again nests lined with dry
grass are found in the tussock bogs. Once ina while, he goes on, a site may be
chosen well inland, among low thickets of the diddle-dee or native heath.
Doubtless the commonest types of nests are on the beach, not far above high
watermark, but among dry seaweed so speckled with lichens as to show that
the water is unlikely to reach it.
Observations upon the young and their care are scarce. As among other
species of oyster-catchers, however, the chicks begin to move about while they
are still small; but they are quick to ‘‘freeze’’ at the sharp signal from the
parent birds, and do not stir again until they receive the announcement of
“~alivelear
BLACK OYSTER-CATCHER
Haematopus ater
Hamatopus ater Vieillot and Oudart, 1825, Galerie Oiseaux, 2, p. 88, 1, pl. 230 (Strait of Magellan).
Names: Black Curlew at the Falkland Islands; ‘‘Ostrero Negro’ is the Spanish book-name;
in Peru the vernacular name is “‘Brujillo Negro.’’ Among specific names, the following four
appear in the literature relating to this species: miger, unicolor, townsendi, quoyi.
BLACK OYSTER-CATCHER 989
Characters: An entirely black species (the only one in South America); from black oyster-
catchers found in other parts of the world, as well as from all white-breasted species, it differs
widely in the form of the bill, the excessive compression and depth of which approach that of skim-
mers (Rynchops). The distinctive character of the bill is apparent even in chicks taken from the egg.
Adults (sexes alike): Head, neck, rump, and entire ventral surface slaty black, with a slight
brownish cast on the belly where, moreover, some of the feathers have barely perceptible grayish
terminal margins; back and upper surface of wings clear brown, varying in hue between raw
umber and sepia, being darkest on the wing quills; tail quills darker than the remiges, or nearly
black; ventral surface of wing and tail quills gray, with a silvery sheen on the outer webs, and with
shafts which are whitish in this aspect though brown dorsally. Iris brilliant opaque yellow; bill
and eyelids red or orange-red; legs and feet pale flesh color or white. The irides of young birds are
yellowish brown; those of chicks brown.
17 males: wing, 253-269 (261.5); tail, 93-106 (99,8); exposed culmen, 68-74.5 (71); depth of
bill, 14.8-16.3 (15.5); tarsus, 52-57 (54.3); middle toe with claw, 48-53 (50.2) mm.
9 females: wing, 251-280 (267.7); tail, 96-108 (102); exposed culmen, 72-84 (79.5); depth of
bill, 15.2-17.8 (16.1); tarsus, 54-59 (57.3); middle toe with claw, 49-54 (51.8) mm.
The measured specimens come from seventeen localities which cover the greater part of the
range of the species.
Downy young are only slightly darker than those of the ‘‘pa/liatus’’ group of Haematopus
ostralegus, which they much resemble. The white area in the downy stage of ater is, however,
confined to the breast, instead of covering also the belly and flanks.
The juvenal plumage, as exemplified by a specimen taken at Ancid, Chiloé Island, on April 17,
1914, is similar to that of the adult except that the head and chest are brown rather than black,
the belly still paler, and the greater part of the body marked with buffy or ochraceous fringes to the
feathers. This is especially heavy on the wings and belly. On the back a subterminal band of
dark brown is also visible on many feathers. The buffy fringes occur upon the forehead and throat,
but scarcely at all on the nape. The tips of some of the primaries are also marked with a light edge.
Evidence of this plumage is carried all through the first year, the light edges being gradually
effaced by wear, but being still perceptible on juvenals taken from May to October. Such birds
have a golden speckled appearance.
The eggs of this Oyster-catcher, when in the nest, are pinkish white, with dark brown and
dull black spots and hieroglyphics. The ground color is thus considerably lighter than in eggs of
Haematopus leucopodus, and the brown markings are inclined to be more streaky than in that species.
Eggs of a series reported upon by Vallentin (1924, 308) measured from 60-68 mm. in length by
42-45 mm. in diameter. Beck took four sets during the Brewster-Sanford Expedition, of which
three were made up of two eggs and the fourth of one. They came from the Falkland Islands and
from islets near Cape Horn. The principal characteristic of their marking is that many of the
blotches and vermiculate streaks are buried more or less deeply beneath the limy surface of the
shell, so that they appear as veiled mottling, much grayer and less distinct than the superficial
areas of pigment. Moreover, these dried shells would be described as of buffy white, rather than
greenish white, ground color. The dimensions of the four sets are as follows: 61.2 x 40.3; 62.9
x 41.2 and 63.3 x 42; 63 x 43.1 and 63.3 x 42.8; 63.7 x 43.2 and 63.3 x 43.7 mm. The eggs of this
species thus appear to be larger than those of any other American species of oyster-catcher, the
eggs of Haematopus leucopodus being next in average size.
Distribution: Coasts of southern and western South America, from islands in the estuary of the
Rio de Ja Plata southward to the Falkland Islands and Cape Horn, and northward along the Pacific
coast at least to latitude 7° S. in Peru. The species breeds throughout this range. It has also been
taken at the Juan Fernandez Islands, where its status is uncertain.
This large and stocky Oyster-catcher, the ‘‘Brujillo Negro”’ or “‘little black
wizard"’ of the Peruvian coast, is a bird of somewhat astonishing distribution.
Naturalists acquainted with it only in a cold and blustery meteorological en-
vironment, near the southern extremity of South America, would naturally
990 OCEANIC BIRDS OF SOUTH AMERICA
regard it as a typical example of the Magellanic bird-world, and would associate
it with the habitats of the Sheath-bill, King Shag, and Slag or more particu-
larly with that of its own close relative, the Pied or Fuegian Oyster-catcher.
Nevertheless, the Black Oyster-catcher seems quite free of certain regulations of
nature which restrict the breeding ranges of the Pied Oyster-catcher and of
many other birds to the Magellanic district. Northward through the Chilean
sub-antarctic islands as far as Chiloé, the Black Oyster-catcher and Haematopus
leucopodus are found together. At this point, however, the northward extension
of the last-named species ends, while the range of the Black Oyster-catcher con-
tinues along the desert shores of Chile and Peru to within seven degrees of the
equator. The species thus represents an extreme combination of sub-antarctic
and Humboldt Current distribution. The only other birds which have quite so
great an extent of continental range are
a few forms, like the Kelp Gull, which
\ are at the same time pan-antarctic, and
the Bigiia Cormorant, which is unique.
Of all the other coastal birds peculiar
to southern South America and the
closely adjacent islands, I should say
that the Black Oyster-catcher occupies
the range characterized by the greatest
continuous length and the most pro-
nounced climatic diversity.
I have compared and measured up-
Fic. 76. Bills of two species of South wards of thirty specimens, taken at
American Oyster-catchers. seventeen localities between Ancén,
Peru, which is north of Callao, and
the extreme southern tip of South
America, by which I mean the very rocks on the ocean side of Cape Horn.
The series includes also eight from the Falkland Islands. Among all these
birds I can see no evidence that more than one race of this Oyster-catcher is
distinguishable, despite the almost anomalous nature of the range.
The coastal extremes iri the Atlantic distribution of the Black Oyster-catcher
appear to be at islands in or near the estuary of the Rio de la Plata, and at Cape
Horn, northward from which along the Pacific coast of the continent the birds
are to be found to Lobos de Tierra Island (latitude 6° 30’ S.), where an example
was observed by Coker (1919, 496). Until recently, Tombo Point, Patagonia,
which: is latitude 44° 6’ S., was considered the northernmost station on the
Atlantic coast (Durnford, 1878, 403), but Smith (1927, 287) has given what seems
to be an indubitable nesting record of this species from the main island of the
Coronilla group, off the coast of Uruguay. He states that he saw several adults
of the Black Oyster-catcher on this rocky islet, and that a nearly grown bird and
two downy young were brought aboard his vessel. Since there is no other black
species of oyster-catcher in South America, I should say that the identification of
this zodlogist may be regarded as conclusive.
Upper, Haematopus ostralegus pitanay, 92;
lower, H. ater, 9.
BLACK OYSTER-CATCHER 991
It is curious that Darwin's comprehensive journal, covering many parts of
the Magellanic region, makes no mention of either of the two resident oyster-
catchers. Practically every other work dealing in part with the ornithology of
the southern South American seashore refers to one or both species. The records
for Haematopus ater are far too numerous to cite, although it is worth noting
that Salvadori (1900, 625) includes it among the resident birds of Staten Island,
and that both von Schalow (1898, 644) and Salvin (1875, 372) record it from
Mas Afuera Island of the Juan Fernandez group. Hellmayr (1932, 382) states
that its occurrence in Mas Afuera is open to doubt, but he has perhaps overlooked
Salvin's explicit testimony that he had examined two specimens from that
island, which agreed with Falkland examples.
Beck collected Black Oyster-catchers at eleven localities between Cape Horn
and the northern end of the Chilean archipelagoes, during the course of the
Brewster-Sanford Expedition. He and I, or other members of American Museum
parties, have shot or observed the bird at the following Peruvian stations:
Chilca Bay, Pescadores Islands, Asia Island, Chincha Islands, Paracas Bay,
Independencia Bay, Santa Rosita Island. From the arid section of the Chilean
coast records are numerous. Farther southward, there are several from Mocha
Island, where Mr. Bullock, moreover, has recently found seven or eight pairs
of these birds breeding around the coasts. On November 29, 1932, he collected
an adult female, which I have examined. Bullock's manuscript states that the
species is found at Mocha during every month of the year. All observers appear
to agree with Crawshay (1907, 125) that the Black Oyster-catcher is exclusively
a shore-dwelling bird.
During my first expedition to the coast of Peru, I became well acquainted
with the Black Oyster-catcher, and found it particularly characteristic of rocky
stretches of coast, or of beaches where shingle, rattling and grinding under the
surf, took the place of sand. Therefore, while the species inhabits the same
region as Haematopus ostralegus pitanay, which might almost be called a pan-
tropical bird, it does not ordinarily occupy the same environment. It may be
said rather to alternate with the white-breasted species, and it is, par excellence,
a bird of the outer coasts and promontories, and of the turbulent, beetling
shores of numerous islands, large and small.
My notes refer in particular to three pairs that evidently occupied contiguous
nesting territories near the northwest point of the mountainous island of San
Gallan, just outside Pisco Bay. The greater part of the water front was here
impracticable to traverse on foot. From the behavior of the birds, I judge that
one pair had a nest very close to the niche of level ground behind the beach in
which I slept on the nights of November 26 and 27, 1919, but, although I
watched them at all times when not otherwise occupied, I failed to spot the
site of their home. These Brujillos were very musical, and piped a great deal as
they flew nervously from the crest of the beach to some small jetty of rock,
and back again. They were incessantly active rather than shy, and at times
they could be approached within a few paces as I walked toward them along
the ridge of the shingle. My Peruvian companions held that their loud, slow,
992 OCEANIC BIRDS OF SOUTH AMERICA
yet excited calling was a sign and an accompaniment of heavy surf, in other
words, a complaint against the pounding rollers that interfered with their
feeding. When the ocean is placid, I was told, the birds utter softer, sweeter
notes, which culminate in a very rapid trill, and which the Peruvians interpret
as their song of contentment. Whether or not the inference is correct, I heard
on many subsequent occasions this pleasing tremolo, to the accompaniment of
waves which lapped the shores rather than assaulted them. Singing or silent,
these Oyster-catchers have a habit of carrying their bright red bills slightly
parted.
In the Falkland Islands, where this bird is known as the Black Curlew, it is
in general less numerous than the other species, although Vallentin (1924, 308)
states that the Black Oyster-catcher is the more abundant in the northern part
of West Falkland. It is the quieter of the two Falkland species and, further-
more, its color tends to make it less conspicuous on the shingle beaches or
against a background of dark kelp. Sometimes the coral bills and pale pink
legs may be picked out by the eye sooner than the body of the bird. The two
species associate in flocks during the winter season, and they come together at
other times to feed avidly upon limpets made sick by the vast masses of rotting
kelp occasionally piled up by storms in sheltered creeks and coves of the Falk-
lands (Vallentin, 1924, 379).
The Black Oyster-catcher lays two eggs at the Falkland Islands about the
beginning of November, or a month later, on the average, than the Fuegian
species (Abbott, 1861, 155). Cobb (1933, 39), however, refers to fresh eggs
found during a season extending from late October to the end of January. In
Peru the birds are courting by September or early October. At Caroline Island,
Chile, Beck found two eggs just hatching on December 9, 1914. A skua was
squatting near-by, as if watching the process hopefully. Beck’s notes also con-
tain the following records from the purlieus of Tierra del Fuego, Chiloé Island,
and the Falklands: a female sitting on eggs, False Cape Horn, December 23;
one fresh egg in a nest within 7 meters of the nest of a Kelp Gull (Larus domini-
canus), Peyron Island, December 19; two slightly incubated sets of two eggs in
nests at the edge of a colony of terns (Sterna hirundinacea), Bleaker Island, Falk-
lands, December 12; two eggs ina nest not far from a gull colony, East Falkland,
December 10; a newly hatched chick with an addled egg in a nest near Port
Stanley, December 7; adults with well-grown young, Ancid, Chiloé, April 7;
a dozen birds, including full-grown young, at a cove near Cuellon, Chiloé,
May 21.
The nests, as a rule, are on the beach, just above high watermark, sometimes
in the lee of stones or boulders, and, according to McCormick (1884, 328), the
parents evince great anxiety, and flutter about with loud outcries, when one
chances into the neighborhood of their home. The nest itself is seldom more
than a slight depression among pebbles or dry kelp, although occasionally a
few bleached twigs or ancient bones enter into its construction. Cobb states
that exceptionally high tides frequently wash the eggs away. The birds them-
selves, like other oyster-catchers, can swim rather well when they need to.
BLACK OYSTER-CATCHER 993
Vallentin reports that nesting pairs can best be approached on horseback.
Then, if both are at the nest, they will walk away singly and slowly. If the
observer dismounts and sits down, one will sooner or later return and, after
strutting about and scolding a bit, will presently settle upon its eggs. Despite
its red bill, a sitting bird is almost impossible to discern among the dried stalks
of giant kelp along the beach, until it moves.
The Black Oyster-catchers feed upon the same sort of food as the Pied species.
A stomach from Elizabeth Island in the Strait of Magellan contained mussels.
Vallentin describes the dexterity with which the birds dislodge limpets (Patella
aenea) from the rock. They approach one of these univalves while it is not
tightly appressed against the stone, quietly place the bill beneath the edge of
the shell, and with a sudden twist of the head detach the mollusk, which is
immediately devoured. Al! the movements are so rapid that it is difficult to
tell, even through binoculars, just how it happens. One point, however, is
very noteworthy, namely that the Oyster-catchers select as prey only the mod-
erate-sized limpets, for example those not more than about 45 millimeters in
diameter. Larger shells are invariably passed by, as though the bird realized
the limit of its strength or the maximum extensibility of its gullet.
The stomach of a specimen I shot on the Peruvian coast was filled with food
made up of the following organisms and proportions: remains of barnacles
(Chthanalus cirratus and Balanus), 38 per cent; one small fish, 30 per cent; one
crab (Petrolisthes spinifrens), 30 per cent; 14 operculi of gastropods (Thais or
Concholepas), 2 per cent.
Cunningham (1871, 123) states that both the Black and the Pied Oyster-
catchers are excellent eating. I did not experiment with the present species,
but the examples which I preserved seemed extraordinarily tough. Their skins
separated from the underlying tissue with more difficulty than in the case of
any other bird I can recall.
THE PHALAROPES
FAMILY PHALAROPODIDAE
The phalaropes, or sea-snipes, are the only truly oceanic shore birds. They
swim well, make long migrations far from land, and two of the three species
spend all or a large part of their non-breeding season in a pelagic habitat.
Structures correlated with such a mode of life include compressed tarsi, lobed toes,
and dense, compact plumage of a texture resembling that of gulls or petrels. Pre-
sumably, the oceanic habits of the phalaropes are secondary, that is, the group
has been derived from some generalized and more terrestrial limicoline stem.
As breeding birds, phalaropes are restricted to the northern hemisphere, all
but one of them, in fact, to arctic or sub-arctic latitudes. In the South American
region they are known only as migrants, or as non-breeders which may remain
south of the equator during the northern-hemisphere summer period. The
three species of phalaropes belong to three genera, and the following key for
the identification of specimens is taken from Ridgway (1919, 417):
994 OCEANIC BIRDS OF SOUTH AMERICA
a‘ Bill broad, somewhat expanded subterminally; nostrils separated from loral feathering by a
space about equal in length to basal depth of maxilla; tarsus not more than one-sixth as long
as wing, not longer than middle toe with claw; lateral merabrane of anterior toes very
broad, the outer margin of the segments strongly convex .......... Phalaropus.
a? Bill slender, not at all expanded subterminally; nostrils close to loral feathering; tarsus at
least one-fifth as long as wing, longer than middle toe without claw; lateral membrane of
anterior toes narrower, the margin of the segments much less strongly convex, or the margin
continuous, without convex segments.
b: Bill attenuated terminally (tapering in both lateral and vertical profiles); tarsus shorter than
exposed culmen, about one-fifth as long as wing, but not longer than middle toe with claw,
lateral membrane of toes broader, distinctly scalloped; tail graduated... . . . Lobipes.
b2 Bill subulate (of nearly uniform thickness, both vertically and horizontally, throughout);
tarsus longer than exposed culmen, about one-fourth as long as wing, decidedly longer than
middle toe with claw; lateral membrane of toes very narrow, not distinctly if at all scalloped;
tailidoublysemarrinatelen., «9.12 ents Ge ye st Oa in Rely ue Sees Steganopus.
The phalaropes are peculiar in that the females of all three species are more
richly colored than the males and are also of larger size. These characters link
up with behavior, for the females are the aggressors or pursuers in courtship,
while the males assume the usual ‘‘feminine’’ rdle in the incubation of the
eggs and the care of the young. Plumage descriptions are given below under
the specific headings, but it must be borne in mind that phalaropes encountered
in South America are certain to be mainly or completely in winter plumage, and
therefore lacking the nuptial pattern which serves readily to distinguish them
at long range. Afloat or ashore, however, phalaropes are usually very tame,
and if they can be examined well, either through glasses or even with the
naked eye, the form of the bill, together with certain plumage markings, is
sufficient for identification. The Red (Phalaropus) and the Northern (Lobipes)
Phalaropes, for example, each have a conspicuous white wing-bar formed by
coverts, but that of the Red Phalarope becomes much more obvious in flight
because white secondary quills also enter into its make-up. The Red Phalarope
is the larger of these two species, though size is untrustworthy and difficult to
determine except when direct comparison is possible. The bill of the Red
Phalarope is, however, relatively heavy, broad, and subterminally expanded,
while that of the Northern Phalarope is extraordinarily slender and needle-like.
These differences can usually be made out even at relatively long range. In
neither species is the bill longer than the head.
Wilson’s Phalarope (Steganopus), the third species, lacks the broad single
wing-bar, narrow white edgings on the coverts producing rather the appearance
of several fine bands which are not discernible at a little distance. Furthermore,
in winter plumage it lacks the conspicuous black post-orbital stripe which is
common to both the Red and the Northern Phalaropes, and the bill, which
is extraordinarily slender, is very much longer than in either of the preceding
species, being definitely of greater length than the head. In general form and
plumage, as well as in the length of its legs, Wilson's Phalarope has a much
more sandpiper-like appearance than either of the others. In the main, it is
also less pelagic than the Red and the Northern Phalaropes. Most of the South
THE \PHALAROPES 995
American records of its occurrence seem to be from coastal regions rather than
from the high sea, although there is at least one conspicuous exception for the
South Pacific, cited hereafter.
Beebe (1924, 28) writes as follows of phalaropes as he observed them in the
waters of the tropical Pacific, at long distances from the continental coast.
Sea-ducks haunt the shallower banks of the coast, gulls trust the air of the widest sea, gannets
dive deep into the waves for their prey, while skimmers plough their tiny furrows through the
ocean, but phalaropes actually live on the surface of the open sea. With their long legs for wading,
with narrow lobes instead of broad webbing between their toes, without the slender, narrow wings
upon which albatrosses hang through days of storm and stress of weather, phalaropes seem little
adapted for pelagic life, and yet here and on the Pacific, hundreds of miles from land, I have seen
them in enormous flocks—daring wind and water, spending the whole winter out of sight of land,
trusting to the floating bounty of the sea for food, and to the buoyancy of their dense plumage and
air-filled bodies for safety. I have never seen them in a full storm, but in a half gale, with spray
blowing, and every watery hilltop fountaining into ugly lashing foam, I have watched their
marvellous seamanship, paddling steadily up wind, able, by some perfected knowledge, to keep
in the sliding, shifting valleys and free of the choking spume-drift.
Vast flocks of phalaropes which, so far as known, included both the Red and
the Northern species but not Wilson's, were noted by both Beck and myself
during our respective field work on the west coast of South America. During
the southward journey from San Francisco to Callao, in December, 1912, and
January, 1913, Beck observed phalaropes frequently from Acapulco, Mexico, to
his destination. The largest flocks were seen off the southern side of the Gulf
of Guayaquil, and from there to the inshore waters near Paita, Peru, on January
3. Again, in August of the same year, he encountered many at Arica, and he
collected examples of the Red species in the latitude of Valparaiso during the
following November and December.
My own notes speak of thousands upon thousands routed off the water by
my steamers and other craft along various parts of the Peruvian coast, during
September, October, December, January, and March. Named localities include
the waters to seaward of Zorritos, Point Parifias, Foca Island, Mazorca
Island, San Lorenzo Island, and the Pachacamac Islands. Both the Red and the
Northern species were observed, but the only examples I collected represented
the latter.
Phalaropes have a curious habit of spinning on the water, both while they
are wandering at sea and while they are feeding in the lakes and ponds of their
breeding grounds. Several observers have offered evidence that this peculiar
action serves as a means of drawing small forms of aquatic life to the surface
from depths beyond the reach of the birds. In the ordinary procedure the
phalaropes revolve rapidly while they beat the water with quick strokes of
their wings, after which they appear to pick up minute floating objects (Pike,
1915, 293).
I found that phalaropes were well known to the Peruvian Indian fishermen
under the name ‘‘Pollito de Mar,’’ which they described to me as a little white
and gray sea bird that comes only during the verano (after September).
996 OCEANIC BIRDS OF SOUTH AMERICA
RED PHALAROPE
Phalaropus fulicarius
Tringa fulicaria Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 148 (Hudson's Bay).
Names: Gray Phalarope. Synonyms of the specific name include glacialis, rufus, platyrhynchus,
rufescens, griseus, and cinereus.
Adult female in northern-hemisphere summer: Anterior and upper parts of head, including
chin, anterior portion of malar and loral regions, and entire pileam down to upper eyelid (except
posterior portion) uniform dark gray or blackish slate; sides of head, including greater part of
loral region and whole of suborbital and malar regions, immaculate white; neck, all round, and
entire under parts deep purplish cinnamon or vinaceous brown; hind neck mixed slate color or
slate-gray and cinnamon; back and scapulars light ochraceous or buff, striped with black; wing
coverts slate color or deep slate-gray, the greater coverts tipped with white, the coverts along
edge of wing grayish dusky; bill greenish yellow Cin life), the tip black; iris brown; legs and feet
pale grayish blue Cin life).
Adult male in northern-hemisphere summer: Similar to the female but slightly smaller and
decidedly duller in coloration; pileum and hind neck streaked with ochraceous or buffy, white on
sides of head more restricted and less sharply defined, and cinnamomeous of under parts usually
slightly paler and broken, more or less, by admixture of white.
Northern-hemisphere winter plumage (sexes alike): Head, neck, and under parts pure white;
the occiput and orbital region slate color or blackish slate; upper parts plain light bluish gray.
16 males: wing, 119-130 (125.2); tail, 59-70.5 (62.9); culmen, 18.5-23 (21.9); tarsus, 19.5-
21.5 (20.7); middle toe [without claw], 19.5-21.5 (20.5) mm.
11 females: wing, 129.5-139 (135.1); tail, 63-71 (66.4); culmen, 21-24 (22.5); tarsus, 20-22.5
(21); middle toe [without claw], 19-21.5 (20.4) mm.
Young: Pileum, hind neck, back, and scapulars dull black, the feathers edged with pale tawny
or brownish buff; wing coverts, rump, and upper tail coverts slate-grayish, the middle wing
coverts margined with pale buff, the upper tail coverts with ochraceous or tawny; head and neck
(except as described) and under parts white, the throat and chest tinged with brownish buff
(Ridgway, 1919, 418).
Distribution: Breeding range holarctic and circumpolar, almost altogether to northward of
the arctic circle. Winters at sea, chiefly in the southern hemisphere, and southward to the latitude
of the Falkland Islands, Patagonia, and New Zealand.
The Red Phalarope is the most northerly member of the family in its breed-
ing habits and probably the most southerly in the extent of its migration. It is
also the most oceanic, travelling almost entirely by sea and rarely being found
inland (Wynne-Edwards, 1935, 294). The southward migration, which may
begin in July, is evidently capable of being very rapid, for examples of the
species have been recorded from near Buenos Aires on August 12, and off Coronel,
Chile, on September 13 (Meinertzhagen, 1925, 326). Other southern-hemisphere
districts in which the Red Phalarope has been taken include the Falkland Islands,
several localities along the coast of Chile, the Juan Fernandez Islands (Schalow,
1898, 644), the Galapagos Islands, and along various parts of a course between
Panama and the Marquesas Islands (Jespersen, 1933, 217).
During the Brewster-Sanford Expedition, Beck collected specimens at Val-
paraiso on November 19, 1913, several of which still show traces of the red
nuptial plumage on the belly and in the under tail coverts. On the voyage
between the mainland and Mas Atierra Island he saw numerous flocks. Nicoll
(1904, 50) reports the species as abundant at Valparaiso in February, and
Meinertzhagen notes specimens collected there as late as March 18.
RED PHALAROPE 997
The Red Phalarope, when in the gray garb of its southern-hemisphere
sojourn, more or less resembles the Sanderling (Crocethia) both in appearance and
in style of flight. It is known to include tiny fish, pelagic crustaceans, and
small jellyfish in its bill of fare, and is said at times to forage in the wake of
whales.
NORTHERN PHALAROPE
Lobipes lobatus
Tringa tobata (sic, lobata in Emendanda) Linnaeus, 1758, Syst. Nat. edit. 10, 1, p. 148 (Hudson's Bay).
Names: Red-necked Phalarope. Synonyms of the specific name include Ayperboreus, fuscus,
ruficollis, vulgaris, angustirostris, tropicus, and antarcticus.
Adult female in northern-hemisphere summer: Upper parts dull dark slate-gray or blackish
slate, the back and scapulars striped with buff or ochraceous; greater wing coverts broadly tipped
with white; chin, throat, and under parts of body immaculate white; sides of neck, fore neck, and
chest plain cinnamon-rufous; bill black; iris dark brown; legs and feet bluish gray, the toes with
joints darker gray or dusky.
Adult male in northern-hemisphere summer: Similar to the female, but slightly smaller and
decidedly duller in coloration, the dusky grayish of upper parts duller and less uniform, the cinna-
mon-rufous of neck almost confined to sides of neck, the chest mixed white and grayish, more or
less tinged with cinnamon-rufous.
Winter plumage (sexes alike): Forehead, superciliary stripe, sides of head and neck, and under
parts, white, the sides of chest washed or clouded with pale gray; pileum grayish, the feathers
with dusky shaft-streaks and whitish margins; a blackish spot in front of eye; suborbital and auric-
ular regions mixed dusky and grayish white; upper parts chiefly gray.
11 males: wing, 102-109 (105.1); tail, 46-50 (48.3); culmen, 21-23 (22); tarsus, 18-20 (19.2);
middle toe [without claw], 18-20.5 (19.5) mm.
11 females: wing, 105-116 (110.2); tail, 48.5-52.5 (50.2); culmen, 20-24 (22.4); tarsus, 18.5-21
(19.8); middle toe [without claw], 18-20 (19.1) mm.
Young: Pileum dusky, with or without streaks; back and scapulars blackish, distinctly mar-
gined with buff or ochraceous; middle wing coverts margined with buff or whitish; auriculars
dusky; forehead, lores, supra-auricular stripe, and under parts white, the chest and sides of breast
sometimes suffused with dull brownish (Ridgway, 1919, 424).
Distribution: Breeding range holarctic and circumpolar, both to northward and southward
of the arctic circle, but in America not south of Labrador and northern Manitoba. Winters in all
oceans of the southern hemisphere, southward to the latitude of Patagonia.
The Northern and Red Phalaropes sometimes travel together and, when the
two are mingled, the streaked back and the noticeably slenderer head and neck
of the present species are perhaps better marks for discrimination than those
mentioned above.
The Northern Phalarope has been taken as far south as the Patagonian coast
in the Atlantic, and Philippi (1902, 65, pl. 27) has recorded and figured, under
the name Phalaropus antarcticus, examples collected off the coast of Chile.
During the winter months of the northern hemisphere, this species is to be
found in vast numbers along the whole length of Peru. We have two males in
winter plumage which I shot, respectively, offshore from the Pescadores Islands,
Ancén, December 15, 1919, and off Talara, January 20, 1925. Other observa-
tions from my notebooks are as follows, the order being from south to north
along the coast:
October 19, 1919. Large flocks in Pisco Bay.
998 OCEANIC BIRDS OF SOUTH AMERICA
December 5, 1919. Flocks off Chilca; very active at five o'clock in the
morning.
October 9, 1919. Thousands in oily looking patches on the water along the
coast to southward of San Lorenzo Island.
October 7, 1919. A flock of about 200 in the Bay of Callao. It moved as a
unit, the birds frequently rising, flying a short distance, and settling together.
Similar flocks encountered while en route toward the Pescadores Islands.
September 10, 1919. Northern Phalaropes in flocks offshore from the Pesca-
dores Islands.
December 8, 1919. Thousands upon thousands flushed by the southbound
steamer near Mazorca Island, and for a long distance southward.
January 23, 1920. Large flocks north of Eten.
January 16, 1925. Two good-sized flocks off Foca Island.
January 21, 1925. Northern Phalaropes abundant everywhere between 6
and 37 kilometers due west of Point Parifias.
January 20, 1925. Enormous flocks off Talara. The birds seem to favor a
special belt of water, just outside the coolest littoral zone. For more than an
hour our launch chugged through their legions.
March 4, 1925. Flocks all along the coast, in foamy, sudsy water, between
Talara and Zorritos.
The last three observations in the list above were made while the counter-
current, E] Nifto, was running southward past Point Parifias. Evidently the
Northern Phalaropes are not incommoded by the high temperatures that speed-
ily follow cessation of upwelling in the Humboldt Current. In current-rips
between Cocos Island and the continent, Beebe (1926, 45) observed flocks of
Northern Phalaropes massed upon the water. They took flight just ahead of
his vessel and followed every zigzag of the foam lines as they sought new feed-
ing grounds. Twice Beebe saw individual birds standing upon floating logs.
WILSON’S PHALAROPE
Steganopus tricolor
Steganopus tricolor Vieillot, 1819, Nouv. Dict. Hist. Nat., 32, p. 136 (Paraguay).
Names: Synonyms of the specific name include wélsoni, frenatus, incanus, and stenodactylus.
Adult female in breeding plumage: Forehead and crown pale bluish gray, the former with a
blackish line along each side; occiput and nape white, passing into bluish gray or slate-gray on
back and scapulars; stripe on side of head, chiefly behind eye, and continued down side of neck,
black, passing on lower neck into rich dark chestnut, this continued backward, more or less
brokenly, along each side of interscapular region, the outer portion of the scapular region also
with a stripe of chestnut; short stripe from above lores to above eyes (not extending to bill),
suborbital and rictal regions, chin and throat immaculate white; fore neck and chest soft buffy
cinnamon, deeper laterally and posteriorly, and fading gradually into creamy buff on breast; rest
of under parts immaculate white; wings brownish gray, the coverts and tertials margined with
paler; rump brownish gray; upper tail coverts white, the longer feathers marked more or less with
mouse-gray subterminally; tail mouse-gray, the lateral feathers irregularly barred on the inner
web and narrowly tipped with white; bill black; iris dark brown; legs and feet black.
Adult male in breeding plumage: Smaller and much duller in color than the adult female, the
beautiful pattern and richly contrasted colors of the latter but faintly indicated.
WILSON’S PHALAROPE 999
Northern-hemisphere winter plumage (sexes alike): Upper parts plain light gray, except upper
tail coverts which, together with superciliary stripe and entire under parts, are white, the chest
and sides of breast faintly tinged with pale gray. ‘
10 males: wing, 116-125 (121.1); tail, 48-54 (51.2); exposed culmen, 28-31 (30.5); tarsus,
28.5-33 (30.1); middle toe [without claw], 22-25 (24) mm.
11 females: wing, 130-137.5 (132.6); tail, 52.5-65 (55.9); exposed culmen, 31-36 (33); tarsus,
30.5-33 (31.7); middle toe [without claw], 24.5-26.5 (25.3) mm.
Young: Crown, back, and scapulars dusky, the feathers conspicuously margined with buff;
wing coverts grayish brown, margined with pale buff or whitish; upper tail coverts, superciliary
stripe, and lower parts white, the neck tinged with buff (Ridgway, 1919, 431).
Distribution: A purely American species, breeding in central and western North America, and mi-
grating to southern South America, where it is found inland to a greater extent than on salt water.
Wilson's Phalarope was described from Paraguay, and at least one of the
synonyms of its specific name is based upon a Chilean specimen. Its migration
takes it southward to Patagonia and even to the Falkland Islands, yet it is
primarily a bird of inland waters rather than of the ocean. Such predilections
are correlated with physical structure. The toes of Wilson's Phalarope lack the
large scalloped lobes and pronounced webbing of the other two species, and it
is distinctly less of a swimmer and diver. Wetmore (1922, 8), who observed
the species on mud flats in the province of Buenos Aires and near saline pools
on the pampas, states that there is little to distinguish it—in its gray winter
plumage—from small sandpipers, though it is readily detected by anyone
familiar with its soft calls.
The only remote pelagic record that I can find for Wilson's Phalarope in the
southern hemisphere is the extraordinary one of Alexander (1927, 247), who
observed the species in latitude 14° 26’S., longitude 100° 40’ W., about halfway
between the Galapagos and Easter Island, on February 26, 1926.
The Brewster-Sanford series includes no specimens from the west coast of
South America, but Beck took 12, equally divided as to sex, about ponds at
Mar del Plata, Argentina, on September 29 and October 12, 1914. No trace of
the breeding plumage remains in any of these; a number of the specimens are
evidently birds of the year. They are all described as having yellow or yellowish
green legs and feet. The Museum Collection contains also two females taken
at Guayaquil, on August 21, 1912, by W. B. Richardson. At least one of these
appears to be a bird of the year, and at any rate the date is doubtless late enough
for the examples to have made a southward migration from the breeding ground.
Meinertzhagen (1925, 342) records birds taken in Ecuador on August 28.
THE SHEATH-BILLS
FAMILY CHIONIDIDAE
The sheath-bills, the only birds without webbed feet that reach the antarctic,
are a curious, aberrant group of shore birds of half circumpolar range. The
one species inhabiting the American quadrant of Antarctica, Chionis alba, was
formerly separated generically from those of the southern Indian Ocean region,
but Peters (1934, 308) now includes all forms within a single genus. The eastern
1000 OCEANIC BIRDS OF SOUTH AMERICA
representatives are sedentary, living on islands close to the Antarctic Con-
vergence. The American species apparently crosses Drake Passage with con-
siderable freedom, between the Antarctic Archipelago and the Fuegian and
Falkland districts. Most, if not all, of the islands of the Scotia Arc appear to
lie within its breeding range.
In the sheath-bill, as Kidder and Coues (1876, 85) have said, we have “‘a
genus with the general appearance, gait, and flight of a pigeon, with the beak
and voice of a crow; with the habits
of a wader, yet dreading the water,
and with the pugnacity and familiar-
ae ity with man of a rasorial bird.’’ The
. .<\" affinities of the sheath-bills, as shown
<< by their morphology, eggs, and be-
Ss havior, have been studied by Coues,
Lowe (1916, 122), Layard (1867, 438),
and others, and their apparent rela-
tionships with skuas, gulls, oyster-
catchers, seed snipes, and other Cha-
radriiformes have been variously
pointed out. Wetmore (1934, 7) places
the family between the seed snipes and the birds of the suborder Lari, thus
removing them from the vicinity of the oyster-catchers, which they seem
in many ways to resemble.
Fic. 77. Head of male Sheath-bill, South
Shetland Islands.
SHEATH-BILL
Chionis alba
Vaginalis alba Gmelin, 1789, Syst. Nat., 1, pt. 2, p. 705 (‘New Zealand"’ = Falkland Islands).
Names: Wattled Sheath-bill, Paddy, Reefer, Kelp Pigeon, Rock Pigeon or Sore-eyed Pigeon,
Snow-drop; ‘‘Ptarmigan’’ to the Norwegian whalemen; ‘‘Paloma Antarctica’’ is a recorded
Spanish name. Synonyms of the specific name include chionis, nivalis, vaginalis, forsteri, necrophaga,
and Jactea. ;
Characters: A white, somewhat pigeon-like shore bird, with a short and stout bill, which on
the maxilla is basally covered by a horny ‘‘sheath."’
Adults (sexes alike, except that males may show more papillation on the bare skin of the face):
Plumage entirely white, over an abundant gray down. Iris brown (Cobb, 1933, 62, reports ‘dark
blue’’); face, which is bare to a point below the eye and more or less carunculated near the base of
the bill, flesh color, the papillae mostly white; bill distally brown, proximally yellow or greenish
yellow, sometimes with reddish or violaceous hues, especially on culmen and gonys; legs and feet
gray or dusky bluish.
4 males: wing, 246-260 (255); tail, 112-135 (126.2); exposed culmen, 30-34 (32.5); tarsus,
42-47 (45); middle toe and claw, 64-65 (64.5) mm.
10 females from the South Shetlands, South Orkneys, South Georgia, Tierra del Fuego, and the
Falkland Islands: wing, 234-255 (242.2); tail, 118-133 (124.2); exposed culmen, 30-32 (30.8);
tarsus, 39-44 (41.5); middle toe and claw, 60-64 (61.8) mm.
Length of body and wing-expanse as reported by Gain (1914, 159) are: males, length, 405-435,
wing-spread, 810-840; females, length, 400-410, wing-spread, 760-805 mm.
In an adult skeleton of unknown sex, the dimensions of the elements of the wing are as follows:
length of humerus 75.6; radius 81.2; ulna 77.1; extreme length of midwing from proximal end of
SHEATH-BILL 1001
ulna to distal point of carpals 84.6; length of hand from carpal break to tip of terminal phalanx
78.5 mm.
Clarke (1913, pl. 2) figures a chick in transition between down and contour plumage. The head,
sides of back and neck, lower back, and abdomen are clad in gray down mottled with brown, the
pileum and nape being brownest; white feathers cover the wings, scapulars, and flanks, indicating
that the juvenal plumage resembles that of adults.
The same author describes eggs from the South Orkneys as elongate-ovate, the white shell
boldly blotched with grayish black or dark brown and liberally freckled with the same colors.
They vary little in size, and measure from 54 to 58 mm. in length by 37 to 39 mm. in breadth.
Distribution: Breeds at islands of the Scotia Arc, including South Georgia, the South Sand-
wich, South Orkney, and South Shetland groups, and various islands of the Antarctic Archipelago
southward beyond latitude 65° S. The species occurs regularly at the Falkland Islands, Staten
Island, the Diego Ramirez Islets, many parts of the Magellanic region, and the Atlantic coast of
southern Patagonia; it may possibly breed in some of these localities.
The Sheath-bill is a puzzling bird as regards distribution as well as relation-
ship; although it is common along the water front of Magellanic South America
and the Falkland Islands, its eggs have never been found with certainty in any
part of this region. Bennett (1926, 32) states, moreover, that at the Falklands
it is less numerous in summer than in winter. Very probably it may prove to
be a breeding species only within the Antarctic Zone of surface water. Its
migrations into milder regions appear to be sporadic rather than regular, for a
large proportion of the population spends even the winter in high southern
latitudes. Observations reported by Eights (1838, 213), Menegaux (1907, 69),
Andersson (1908, 53), Wilkins (1923, 494), and others tell us, for instance,
that Sheath-bills are of regular occurrence throughout the year at such localities
as Elephant Island, Deception Island, Paulet Island, and even farther southward
in West Antarctica. :
Since the Sheath-bill is a practically omnivorous scavenger, the presence of
human beings at the more southerly stations may have more or less to do with
its persistence in residence. Thus Gain (1914, 159) states that after the antarctic
winter had set in at Petermann Island, Sheath-bills gathered in April and May
from surrounding localities to spend the lean months of the year about the win-
tering station of the French Expedition. Valette (1906, 584) also reports that
at the South Orkneys Sheath-bills were his only familiar winter companions
among the birds, and that they appeared daily at the door of the hut of the
Argentine meteorological observers in order to accept left-overs from the table.
Toward the end of August these birds quite inexplicably disappeared, the reason
not being learned until early September, when the Sheath-bills were accidentally
discovered on the outlying pack-ice, living around the nurseries of Weddell
seals and finding a rich larder in the placental blood and afterbirth of new-born
cubs. Valette even saw several of them attempting to devour the umbilical cord
while it was still attached to the baby seals! Members of the wintering Scottish
Antarctic Expedition at the South Orkneys likewise had the company of at
least a few Sheath-bills throughout the dark season, the birds dispersing in
spring only after activity in the penguin colonies had commenced. Finally,
Lester (1923, 174), who wintered on the Danco coast beyond latitude 64° S.,
also found the Sheath-bill to be the only resident bird in winter. At his base
1002 OCEANIC BIRDS OF SOUTH AMERICA
they subsisted largely upon scraps of seal meat left by the dogs, and anything
else they could steal. Their numbers about camp varied from two to ten, and in
one respect, at least, they proved a nuisance, for, recognizing by scent or in
some other way the seal oil with which the canvas roof had been waterproofed,
they devoted much of their time to trying to peck through it.
The travels of the Sheath-bill are of extraordinary interest and are still very
imperfectly known. At times the birds have such strong grouse-like terrestrial
proclivities that one might doubt their ability to take wing at all. They have,
nevertheless, a strong, pigeon-like style of flight, and not only do they cross
the broad expanse of Drake Passage, but they have been casually observed in
many parts of the southern ocean at a great distance from land. Furthermore,
they have been seen on floating ice, in company with Adélie and Ringed Pen-
guins, as reported by Donald (1894, 333), and it was, no doubt, through a
combination of long flights and ice-ferrying that birds of the genus Chionis
originally acquired their present distribution, which extends more than a third
of the distance around the world in the zone of westerlies. For such reasons I
confidently expect the discovery of some form of Sheath-bill at Bouvet Island,
from which none has yet been reported.
Darwin, for one, was impressed by the great distances from land at which
the Sheath-bill was to be seen (Gould, 1841, 118); Reichenow (1908, 566)
reports sighting them ‘‘300 miles’’ at sea. One still farther astray, ‘400 miles
from the nearest coast,’ is recorded by King (1839, 538), who also writes that
somewhat nearer South America a Sheath-bill flew aboard his ship. A similar
happening is mentioned by Stenhouse (1929, 186) who states that during the
cruise of the ‘Adventure,’ between the years 1826 and 1830, an example flew on
board. Andersson (1908, 43) saw this species far east of the Falklands in latitude
52° 22’ S., longitude 54° 26’ W., namely, in the direction of Shag Rocks and
South Georgia. On April 3, 1842, a Sheath-bill hovered above the masts of
the ‘Terror,’ in latitude 57° S. or thereabouts, two days before Beauchéne
Island, the southernmost of the Falklands, was sighted (McCormick, 1884,
280), and “‘about 100 miles off Cape Horn’’ two once alighted in the rigging of
a ship (Fristedt, 1894, 330). Paessler (1913, 46) saw a pair in flight over the
ocean a long distance to eastward of Puerto Deseado, Argentina, and during the
course of the Brewster-Sanford Expedition Mr. Beck was surprised to find that
Sheath-bills frequently flew up astern of his schooner when he was far at sea,
and behaved, while they remained, almost like oceanic birds such as petrels
or gulls. Eights states that Sheath-bills which had become practically domes-
ticated at the South Shetland Islands elected to remain on the ship when it
departed! It would be hard to credit such a story were it not for the support
of Moseley (1879, 209), who writes that a Kerguelen Sheath-bill attached itself
to the ‘Challenger’ during the southward voyage to Heard Island, occasionally
leaving the vessel to fly around and then return.
On the east coast of South America the Sheath-bill apparently ranges north-
ward at times to the neighborhood of the Gulf of San Jorge. Rio Gallegos is a
favorite winter headquarters, and in this region, at Punta Loyola, Beck found
SHEATH-BILL 1003
about 40 of them feeding on mussel beds with the gulls during August, 1915.
At this time the weather was cold and the ground frozen. The Sheath-bills
were not in the least shy, and would permit approach within photographing
distance, provided Beck moved cautiously. The natural response of these birds
is often simply to gather around anyone who takes them by surprise, rather
than to be startled and to fly away. If a stone is thrown at them, they some-
times merely look at it as though amused, and watch it roll.
At the Falklands, Beck found that the Sheath-bills he collected during the
southern-spring period were birds with non-functional gonads, a fact which
would tend to confirm the supposition that they do not breed in this sub-
antarctic locality. Doubtless such examples should be regarded not as migrants
to the Falklands, but rather as birds which lacked the physiological incentive
to return to their antarctic nesting grounds. Cobb (1933, 62) states that he has
counted more than 100 Sheath-bills together at Bleaker Island during the
months of May and October. Their favorite resorts here are about the penguin
and shag rookeries, where they are constantly on the lookout for both drop-
pings and eggs. A joyful and almost humanly sentient greeting they give to
any man who seems likely to disturb a colony of cormorants and thus to open
up a supply of eggs. At some real or fancied alarm the Sheath-bills all be-
have as though they had a recognition of guilt, rising as one bird, clearing
out of the rookery, and subsequently sidling furtively back again, one by one,
on foot.
At South Georgia we enter the known nesting ground of the Sheath-bill.
For some reason the birds seem to have become greatly reduced in numbers at
this island, for, during my own visit in 1912 and 1913, I saw extraordinarily
few in comparison with the population indicated by earlier accounts. Possibly
the whalemen have shot them off as game, for, despite their none-too-pleasant
feeding habits, Fristedt states that they are delicious eating. The fact that the
Norwegians at South Georgia call them ‘‘Ptarmigan’’ no doubt bodes ill for
their welfare. Olstad (1930, 7) states, furthermore, that their eggs are con-
stantly destroyed by the introduced rats, so this, too, adds to the possible causes
of the diminution in their numbers. The first Sheath-bill I saw at South Georgia
appeared on a ledge of rock at the Bay of Isles, while I was passing beneath it
in a whaleboat. The behavior of the bird was extraordinarily pigeon-like as
it minced along, keeping abreast of us out of sheer curiosity, and bowing and
nodding at every few steps.
About the middle of October, according to several accounts, the Sheath-
bills, which gather in localities favorable for shelter and food during the deep
snows of South Georgian winter, rather suddenly disperse for the breeding
period and are, thereafter, much less conspicuous until the following autumn.
Possibly this is the true reason why I saw so few of the birds, for, since the date
of my summer visit, Wilkins (1923, 485) has found an average of one Sheath-
bill to each three kilometers while following closely a long stretch of the coast.
About the time of the first snows they tend to resume their barnyard and dump-
heap habits, and the long period of their aloofness and independence makes no
1004 OCEANIC BIRDS OF SOUTH AMERICA
difference, as Valette has remarked, as to their renewed fearlessness and sociabil-
ity toward human beings.
I find no information regarding the courtship of Sheath-bills in American
Antarctica, but that of the Indian Ocean species (Chionis minor) has been de-
scribed as extraordinarily pigeon-like, the male bowing and bobbing and strut-
ting about, making a cooing sound all the while (Moseley, 1879, 209). The
nests at South Georgia are built among large blocks of stone not far from the
water, as a rule, and are composed of wisps of tussock grass, algae, moss, and
feathers, usually more or less strewn over with bits of decayed food, limpet
shells, and other refuse. Valette states that the nests he found at the South
Orkneys were far from works of art, despite the great amount of small bones,
fragments of eggshells, mollusks, and the moulted tail feathers of penguins,
which had been dragged in among clefts of the rocks. Bennett (1926, 321) once
found a bulky nest made entirely of penguin rectrices. When returning toward
their homes from feeding expeditions, the Sheath-bills usually alight upon some
conspicuous rock in the vicinity and then dart for the hidden sites.
The Sheath-bill lays two or three eggs which, according to Bennett (1927,
259), appear more than a week apart, as a result of which the chicks, while all
are still alive, are likely to be even more different in size than the young of
penguins. With the appearance of the first egg, one parent immediately com-
mences to incubate. This custom is the usual one among antarctic birds, because
frost is always a factor to be reckoned with, and numerous eggs are burst by the
cold. Most observers agree that more than one Sheath-bill chick in a family is
rarely seen at South Georgia, and it is probable that the other one or two are
either eaten by the parents or succumb because of the long intervals between
the laying of the eggs. Possibly the Sheath-bills, like the skuas, are not easily
conditioned to more than one egg or chick, which may account in some degree
for the partial elimination of their own offspring. This is always a likelihood
among birds which are as ready to devour the eggs and young of other species
as the Sheath-bills are. Lowe (1916, 122) states that the chicks are apparently
nidicolous for some time after hatching, but all field observers report them
running about actively while they are still very small. S6rling, as related to
Lonnberg (1906, 56), captured two mated pairs of Sheath-bills at South Georgia,
and the chick of one of the families. The parent birds in captivity continued
to feed and brood their young one; these parents, however, escaped from their
cage, whereupon Sérling transferred the chick to the other enclosure, and it
was at once adopted and cared for by the other pair of adults.
Nest-building at the South Orkneys begins toward the end of November,
and by the middle of December, according to Valette, all the birds are incubat-
ing. Eggs have been procured in the Antarctie Archipelago by December 19,
and downy young still in the nest at Paulet Island on January 15. A single
large downy chick, first observed at Hope Bay on February 24, moulted practi-
cally all of its down during the next two days (Andersson, 1908, 53).
Fresh eggs marked on December 11th hatched on January 7th, an incubation period of twenty-
eight days. The newly-hatched young are clad in brown down and show conspicuous bare patches;
SHEATH-BILL 1005
they are not by any means pretty objects like the young penguins and skuas. On January 29th
white feathers were beginning to develop under the down of these chicks; and by February 11th
the down had nearly all disappeared (Clarke, 1913, 245).
The Sheath-bills are both sociable and quarrelsome among themselves. At
times they seem to enjoy each other’s company, and even to play together by
chasing one another around a rock and back again. Upon the first sign of com-
petition in feeding, however, they stand up to each other and tlt, or stretch up
on tiptoe, open their greenish bills, and utter angry cries. Toward other animals
they are fearless and impudent. They walk about on the backs of sea-elephants,
exciting no more response than the traditional flea on the bull’s horn. Of cats
and dogs about the whaling stations they are no more afraid than of man. In
fact, the one creature of which they evidently stand in awe is the skua, and
with this bird alone they avoid rivalry around a seal carcass. However, Valette
tells us that actual fear of the skua is shown only during the first few days
after the latter's arrival at the South Orkneys. Later, he states, the Sheath-bills
acquire a feeling of indifference, if not of amity toward it. Of course, the
intimate relationship between the Sheath-bills and many other birds with
which it associates is hardly ever without malice aforethought. At the South
Orkneys one has been seen calmly boring in under an oblivious incubating shag,
with the object of extracting an egg from the nest (Brown, Mossman, Pirie,
1906, 174). The fact that the Sheath-bill should be an inveterate egg-thief 1s
by no means as remarkable as Lowe (1916, 122) believes, because this trait is
a widespread one among birds of limicoline affinities. No one, perhaps, would
suspect the Bristle-thighed Curlew or the Turnstone (Arenaria) of being accom-
plished nest robbers, and yet they are.
During the summer the Sheath-bills bathe frequently at the shallow edges
of the cold coves. They seem to have a certain dread of deep water, and will
test it mincingly before feeling quite content. Nevertheless, they can swim
well when necessary, despite the fact that their feet are unwebbed. In winter
they react to low temperatures in several different ways. Valette states, for
instance, that at the South Orkneys they often retire, for the duration of the
short spells of extreme cold to which these islands are subjected, to natural
caverns of the rocks well up on the slopes of the hills. Furthermore, they puff
out their feathers during the cold to increase their blanket of atmospheric
insulation, causing themselves to look like white balls of fluff. They are fat to
begin with, for they are practically blubber-covered, like a seal, the layer over
the abdomen often being a centimeter or more in thickness. Finally, they tuck
up their feet alternately among the feathers of the belly, and hop about one-
leggedly, even while feeding. Valette has observed the Sheath-bills going
about their usual activities when the thermometer registered —42.2° C., which
is exactly 40° below the Fahrenheit zero. He determined the body temperature
of these birds as +40.2°C. The figure obtained by the naturalists of the Scottish
Expedition is slightly higher, namely 41.8° C.
Except in places where their confidence has been abused, the Sheach-bills
are easy to catch in the hand, their immediate reaction to which is to defecate.
1006 OCEANIC BIRDS OF SOUTH AMERICA
It seems as though this were as specific a defensive mechanism as the response
of the Giant Fulmar to disgorge through the beak. Von den Steinen (1890, 216)
found that Sheath-bills very quickly became suspicious of a trap. The first few
birds he caught easily, but after that the others would not succumb to the ruse,
even though a live bird were left inside as a decoy.
In addition to its predacious foraging and scavenging, as described above,
the Sheath-bill also feeds much in the intertidal zone, devouring some algae
as well as a wide variety of animal life. Small fishes, limpets and many other
mollusks, lichens, the shells and contents of birds’ eggs, and pebbles, have
been found in the stomachs of specimens dissected by many of the authorities
already quoted.
In connection with the feeding habits of this curious bird, the morphological
notes published by Valette are of interest, particularly his reference to the very
large intestinal caeca. According to his measurements, the entire alimentary
tract 1s 155 centimeters long, the length of the respective elements being as
follows: esophagus 15; stomach 7; small intestine 125; large intestine 8; length
of each caecum 25 centimeters.
The Sheath-bills drink like gulls, filling the beak and then lifting it high
to swallow; when the water is frozen they have been observed to eat snow.
I judge that the offensive odor of the Sheath-bill, mentioned by several ob-
servers, is associated chiefly with the eating of carrion. The birds I skinned
had no distinctive odor.
THE SKUAS AND JAEGERS
FAMILY STERCORARIIDAE
Tue Skuas, GENUs CATHARACTA
The great skuas, as distinguished from the lesser skuas or jaegers, comprise
a bipolar genus of predacious sea birds, of which one form inhabits the northern
hemisphere and several the southern. If all of these forms are to be regarded as
representing a single species (Catharacta skua), as arranged by several recent
reviewers, we have here the only example of a bipolar species to be found in
the whole class of birds. However, I regard it as still an open question whether
the skuas may not comprise at least four species, of which one is the sub-arctic
bird, a second that of the South American coasts, a third the circumpolar high
antarctic form, and a fourth the circumpolar group of lower antarctic and sub-
antarctic distribution, which is admittedly made up of two or more subspecies.
The solution of this problem rests less with laboratory systematic work than
with observation in the field. Claims in the literature, which are to some
extent supported but not fully confirmed by specimens, indicate that more than
one kind of skua may nest at the same locality as, for example, the South
Shetland Islands. Such a situation, if authenticated, would be entirely out of
line with the whole conception of subspecies, and would indicate that the
THE SKUAS AND JAEGERS 1007
various representatives of the group are biologically more distinct one from
another than is suggested by their differences of color or dimensions.
Whatever value may ultimately be assigned to the different types of skuas
associated with definite breeding localities, it is certain that these birds are
excellent examples of a somewhat unconventional type of differentiation in
nature. One reason is that an extraordinarily wide range of similar variation
seems to characterize most of the different species or subspecies. In other words,
a distinctive average type of plumage may develop among the members of a
single race, but this in almost no case seems to apply to the entire population.
There is, on the contrary, always a small proportion which exhibits a range in
color and pattern almost as wide as that within the genus as a whole. For such
reasons, taxonomic distinctions must be based upon average differences rather
than universal differences. Measurements seem to be of little more practical
avail than pattern and color because of their wide range among the members
of any segregated breeding population, and because of an apparent tendency in
some instances for the birds nesting within a single region to fall into two size
groups, the differences between which are related neither to age nor sex. For
all such reasons it becomes extremely difficult to find intrinsic characters by
means of which the various forms of the skua may be classified without the
necessity of referring to geographic names on the labels. Even with the last-
named help, indeed, the difficulties are by no means ended, for I have seen a
large number of well-labeled specimens, taken at points far from breeding
grounds, which do not fit properly into series of any of the breeding populations
thus far known.
It should be added that the migratory travels of skuas still appear to be full
of mysteries and anomalies. According to the latest description of ranges
(Peters, 1934, 309), the Northern Skua wanders only as far southward in the
Atlantic as New England and Gibraltar. The Chilean Skua, however, is credited
with crossing the narrow zone of tropics in the eastern Pacific and leaping, so
to speak, from the Humboldt Current to the California Current, in which it
has occurred as far north as British Columbia. Furthermore, the South Polar
Skua, which breeds chiefly to southward of the antarctic circle, has been taken
two or more times off Japan. I have compared a specimen from the Sagami Sea,
which is now in the Museum of Comparative Zodlogy, with numerous examples
taken in Ross Sea and Weddell Sea, and I find that this Japanese bird is an exact
counterpart of those from the Antarctic. Finally, Forbush (1928, 51) reports
that skuas of some sort are most plentiful on the Grand Banks of Newfoundland
during July, August, and September, and that they have likewise been found
in numbers on the fishing grounds off Nantucket between June 19 and Novem-
ber 5. It has been suggested that these skuas, which occur in the temperate
North Atlantic during the breeding season of the northern-hemisphere form,
may perhaps be migrants from some of the sub-antarctic or antarctic breeding
grounds. This is a problem which can be solved only by adequate collecting
and comparison. In Part I of this book (p. 138), I have already reported the
presence of skuas between the equator and the West Indies during the month
1008 OCEANIC BIRDS OF SOUTH AMERICA
of May. The region belongs to intermediate latitudes, in which no specimens
of either the northern or the southern forms have thus far been collected.
Lowe and Kinnear (1930, 113) have recently made a detailed study of the
pan-antarctic skuas and of the South Polar Skua, arriving with some diffidence
at the conclusion that all the skuas in the world comprise a single species
which breaks up into seven geographic races. Their long tables of measure-
ments present some of the difficulties to which I have called attention above,
and they admit that it is very difficult to gauge the extent to which an
acknowledged geographical segregation of color characteristics can be
delimited or defined. The last clause refers to the fact that a cinnamon-red
suffusion is a feature of the Northern Skua and of the so-called Chilean
Skua, while it is altogether lacking in the South Polar Skua. Among the
birds of the sub-polar, pan-antarctic islands, such as the Falklands, the
islands of the Scotia Arc, Tristan da Cunha, the Crozets, Kerguelen, and
the islands south of New Zealand, this cinnamon-red character is more or
less sporadic.
It has remained for Hamilton (1934, 163) to analyze the figures presented by
Lowe and Kinnear and, through the use of frequency-distribution graphs based
upon fairly large series of specimens, to illuminate a highly puzzling subject.
While Hamilton does not by any means succeed in answering the question as to
whether the skuas comprise one species or four, he does throw much light upon
the pan-antarctic birds inhabiting seven or more groups of islands, and it is
these in particular which are the most puzzling members of the genus. No
unprejudiced ornithologist, I am sure, can look at the graphs of Figure 1 in
Hamilton's paper without realizing that this is the method by which such
problems should be approached, and that it is one which could be applied even
more usefully to a larger mass of statistical data. Apart from the clear pictur-
ing of the normal range of variation, these graphs illustrate the true place
of the anomalous or exceptional dimensions which always crop out, even in
relatively large series of organisms, and which have in many instances been
the bane of systematists. In former studies of my own, relating to shear-
waters of the genera Calonectris and Puffinus, I have called attention to the
usefulness of similar graphs in interpreting such problems (Murphy, 1924, 248;
1927, 11).
Another interesting result of Hamilton's statistical work is his exhibition
in percentages of the departure from the mean, and the amplitude of variation,
in the dimensions of skuas from various breeding grounds. Such data, when
based upon an adequately large number of wholly comparable specimens, will
eventually enable us to comprehend the amount of normal variation to be
expected within a single race of birds, a conception which cannot fail to be of
great aid to sound and conservative taxonomic work. The following table
gives Hamilton's figures for his largest series of skuas from one locality, to-
gether with corresponding data concerning other species of sea birds taken from
earlier papers of my own. The point is that the normal extent of variation
seems to be of closely similar grade among species not closely related.
THE SKUAS AND JAEGERS 1009
Rance or Size VARIATION, Per CENT
Lengths of
Wing Bill Tarsus
40 specimens of the Falkland Island Skua (Hamilton,
IESE Y ENG) SAE AM Se ans Ey 208 € ae eee 10.6 16.9 13.3 %
100 breeding males of the South Georgian Diving Petrel
@Murcphy and) Harper; 19215529), a0. Seer a sone 16 13.4 16.4
97 specimens of the Atlantic Wilson's Petrel, including
moulting and immature birds (Murphy, 1918, 127).. . 14 17 16
100 breeding specimens (50 of each sex) of the Cape Verde
Shearwater (Murphy, 1924, 246)........... 12 22 15
100 breeding specimens (50 of each sex) of the Azorian
Shearwater (Murphy, 1924, 247)... .....2... 10.9 18.4 14.3
Hamilton has taken full account of previous research into the status of the
skuas, including the pioneer work of Saunders and others, as cited by Mathews
(1912, 491). Following is a summary of Hamilton's conclusions regarding the
several groups, together with a critique based upon my own studies which, to
only a slight extent, have led me to hold opinions differing from his.
1. The Northern Skua (Catharacta skua skua) is geographically isolated from
the others. It has usually, but not always, a strong chestnut cast in its plumage.
2. The Chilean Skua (Catharacta skua chilensis), a bird of both coasts of
South America, is suffused with an even deeper chestnut or cinnamon color
than the Northern Skua. Hamilton adds, however, that this form “‘extends
to the Falkland Islands also,’’ and states that on the eastern side of that group
he has seen it mixing freely and breeding with the native Falkland form! Such
a condition is biologically impossible if the Chilean and Falkland Skuas are to
be regarded as races of a single species. Furthermore, Hamilton has here failed
to heed his own warning that “‘field observations must be accepted with reser-
vation’’ (p. 164), for all of the forty specimens he actually collected at the Falk-
lands proved to be of one race, and the same is true of about twenty examples
taken at these islands by Beck during the Brewster-Sanford Expedition, as well
as of as many more that I have examined in various museums.
I believe that the explanation of Hamilton's statement is made clear by
several of our American Museum skins from East Island and Bleaker Island, of
the Falklands, which show a much more rufous condition on both the back
and the breast than do most Falkland birds. In other respects, however, such
as in their relatively smaller bills, these reddish birds agree with their Falkland
neighbors rather than with birds from the breeding center of chilensis among
the Magellanic islands. The only conclusion that we are justified in making is
that there is a certain overlapping in the plumage characters of the Chilean and
Falkland Skuas, although the average difference in appearance is quite marked.
The same may be said regarding other races or units of these puzzling birds.
3. The South Polar Skua (Catharacta skua maccormicki) is a strictly antarctic
form distinguished by the entire absence at all stages of chestnut coloring, to a
1010 OCEANIC BIRDS OF SOUTH AMERICA
certain extent by the peculiar vinous tinge of the lower surface, and usually by
the presence of a collar of more or less golden, acuminate feathers.
Hamilton (pp. 173, 174) infers that the true South Polar Skua does not occur
at the South Shetland Islands, from where it was abundantly recorded by Gain
(1914, 109). He states that during the course of a number of visits to the
South Shetlands made by Mr. A. G. Bennett and himself no specimens of mac-
cormicki have been collected, and that the whole area, as far south as latitude
65° S., is occupied by a different and darker form.
That the last statement is erroneous is indicated by the fact that Mr. Bennett
has sent to the American Museum two absolutely typical examples of maccor-
micki collected at Wilhelmina Bay, on the Danco coast (64° 30’ S., 62° W.), on
February 8, 1922. These are quite indistinguishable from specimens taken in
the polar regions of Weddell and Ross Seas. It thus appears that the breeding
ranges of the South Polar Skua and of a form of the “Brown Skua,”’ which
occupies many islands of the Scotia Arc, actually do overlap in West Antarctica,
as alleged by Gain. If such distribution becomes confirmed, it will clearly be
necessary to recognize the South Polar Skua as a fully distinct species from
those inhabiting the islands to northward.
4. The “Brown Skua,’’ as recognized by Hamilton, comprises two sub-
species, of which one (antarctica) is found at the Falkland Islands (and also
according to Hamilton at the South Shetlands, but the specimens I have seen
compel me to disagree with this). The remaining “Brown Skuas,"’ which
Hamilton calls by the inclusive subspecific name Jénnbergi, occupy the remainder
of the world’s antarctic and sub-antarctic islands, such as the South Orkneys,
South Georgia, Tristan da Cunha and Gough, the Prince Edward, Crozet, and
Kerguelen groups, and the southern outliers of New Zealand. With these I
should also include the large dark birds of the South Shetland Islands, as will
be pointed out below.
Hamilton's statistical studies indicate that the last word has by no means
been said regarding finer subspecific division of the skuas at these various in-
sular groups. He makes it clear, for example, that the breeding skuas of the
Tristan region cannot be lumped with the birds of the Falkland race, as they
have been to date. The important point in his conclusions is merely that the
skuas of all the circumpolar islands, from the Scotia Arc eastward to New
Zealand, are at least more closely related to one another than they are to skuas
belonging in other geographic ranges.
Hamilton has stated a matter which I can abundantly confirm, namely, that
plumage characters among the skuas are in the main of very doubtful taxonomic
value because of the enormous variation among the several groups. It may be
true that the cinnamon or rufous coloration never appears in the South Polar
form, but I know of no other qualification which can be defended as a general °
tenet. There are relatively dark as well as pale members among the South
Polar birds. Falkland and South Georgia specimens likewise exhibit every
phase between very pale and very dark birds, and some of them show pronounced
golden hackles. I have seen light examples from the Falklands, moreover,
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1012 OCEANIC BIRDS OF SOUTH AMERICA
which have a clear vinous belly, indistinguishable from the ventral surface of
many typical examples of maccormicki. Furthermore, as already noted, rufous
feathers may be present in both the back and belly of Falkland specimens. In
addition to well-marked average differences, it may be said also that probably
no specimens from the Falklands, or other islands north of the antarctic circle,
have the clear straw-yellow heads and necks of the lightest phase of the South
Polar Skua. Finally, it appears that even the very red form, chilensis, also has
a somewhat rare dark brown phase, without a trace of rufous coloration. At
any rate, I can explain in no other way three such examples taken in the Hum-
boldt Current, off the coasts of Peru and Chile.
While the measurements of Lowe and Kinnear and those of Hamilton fead
to many of the same conclusions as do the figures I myself have recorded, there
are uniform discrepancies between the two series which evidently result from
a slight difference in technique. Thus most of Hamilton's figures for bill length
are somewhat shorter than mine derived from birds of the same respective
regions. In making my own measurements for this dimension, I inserted the
calipers between the feathers of the forehead until the point rested at the very
base of the horny covering of the maxilla. The accompanying table and the
subsequent discussion are, therefore, based entirely upon specimens compared
and measured by myself in the American Museum of Natural History and else-
where. These data relate entirely to southern-hemisphere birds of the South
American region, and they are listed in the same order as that of the digest of
Hamilton's conclusions given above. Among skuas in general there seems to
be no size difference dependent upon sex. Average measurements for males and
females approximate the same figures in adequate series of properly comparable
specimens. I have, therefore, not segregated the sexes in my table. Further-
more, since I cannot decide whether the skuas represent one species or four
species, I am for the present arbitrarily regarding all of them as geographic
races of a single species.
Since descriptions of the southern-hemisphere skuas can most intelligibly
be given in comparative terms, I append descriptions of the Northern, Common,
or Great Skua taken from Ridgway and from Witherby.
Catharacta skua skua Briinnich
“Adults (sexes alike).—General color dull grayish brown, the interscapulars, scapulars, and
wing-coverts with median streaks of pale cinnamon, the feathers of head and neck with similar
but narrower streaks; under parts somewhat paler than upper parts, usually more or less suffused
with cinnamon, the sides and flanks indistinctly striped or broadly streaked with the same; remiges,
primary coverts, and alula dark grayish brown or dusky, the primaries white basally, forming a
distinct patch, the concealed basal portion of secondaries also white; tail uniform dusky; bill
dusky horn color or dull blackish; iris dark brown; legs and feet dull blackish.
“Young.—Head, neck, and under parts plain grayish brown, the last tinged with cinnamon or
dull rusty; upper parts darker grayish brown, paler on back and lesser wing-coverts, where indis-
tinctly spotted with dull rusty or cinnamon; otherwise essentially like adults, but bill, legs, and
feet more brownish.
“Downy young.—Plain buffy or cinnamomeous gray, darker (sometimes more cinnamomeous)
on upper parts’’ (Ridgway, 1919, 677).
THE SKUAS AND JAEGERS 1013
‘Adult male and female.—Fore-head and crown dark brown, distal portions of feathers with
broad central streaks (not very prominent) of pale rufous-brown (often a few white feathers on
head); feathers of back and sides of neck lanceolate, and dark brown with prominent straw-yellow
median streaks; mantle, scapulars and upper tail-coverts dark brown, distal portions of feathers
with broad central streaks of rufous, centre of tips paler and becoming whitish when worn; back
and rump same but rufous and pale tips less conspicuous; lores, round eyes and chin more uniform
dark brown, but feathers more or less tipped yellow-buff; throat streaked and marked rufous and
pale buff but not so prominently as sides of neck; rest of under-parts grey-brown mottled rufous
and feathers of flanks and under tail-coverts with more prominent central tips of pale buff and
rufous; axillaries and under wing-coverts dark brown, feathers with varying amount of rufous at
tips; tail black-brown, white at extreme base concealed by coverts; primaries black-brown, white
at base (on outer 5 feathers 30-60 mm. beyond coverts and making larger white patch on under-
wing), in outer (2nd) primary outer web only white at extreme base which is almost concealed by
coverts, four inner primaries and secondaries black-brown with concealed basal part of feathers
white, shafts of primaries whitish-straw almost to tips and those of secondaries on basal two-
thirds; primary-coverts black-brown; rest of wing-coverts as upper-parts but greater with only
small rufous and pale central tips. This plumage is probably attained by a body-moult early in
year, but no birds from Jan. to March are available. Winter.—One adult (Dec.) is moulting
remiges and wing-coverts and body-moult is nearly complete, while others from June to Sept. are
moulting on body but not wings or tail. New feathers of neck are rounded and brown without
straw-coloured median streaks, and there is no yellow-buff on feathers of throat and ear-coverts,
otherwise plumage appears to be like summer’’ (Witherby, 1924, 777).
CHILEAN SKUA
Catharacta skua chilensis
Stercorarius antarcticus b. chilensis Bonaparte, 1857, Consp. Av., 2, p. 207 (Chile).
Names: Cinnamon Skua; ‘‘Gavioton"’; ‘‘Pajaro Ladron"’ or ‘‘Halcén de Mar’’ in Chile and
Peru. Synonyms of the specific name include several which have been applied to skuas in general,
such as antarctica and catarractes.
Characters: One of the two smaller forms of southern-hemisphere skuas, the other notably
small-sized race being that confined to the Falkland Islands. Typically the brightest and most
cinnamomeous of all skuas, though “‘brown’’ phases perhaps exist. Nearly all adult examples,
however, differ from the Northern Skua in that the axillars, under wing coverts, and ventral sur-
face are mostly cinnamon or cinnamon-rufous, instead of grayish brown. The general plumage-
pattern is in other respects generally similar to that of the Northern Skua. Iris brown; bill dark
reddish umber; tarsi black, sometimes mottled with yellowish; toes black, the webs dusky brown.
Measurements of about 30 specimens are recorded in the table on p. 1011. The following dimen-
sions refer only to adults from breeding stations:
7 males from nesting grounds at islands near Tierra del Fuego: wing, 390-398 (394.8); tail,
140-158.4 (148.3); exposed culmen, 49.4-56.1 (52.2); tarsus, 60.6-72.3 (68.6); middle toe and
claw, 74.3-75.5 (74.9) mm.
5 females from the same localities: wing, 387-411 (395.6); tail, 135.6-143 (139.1); exposed
culmen, 51-56 (53.3); tarsus, 66-70 (68.2); middle toe and claw, 72.1-77.5 (74.7) mm.
Youthful examples have less solid cinnamon coloration on the feathers than adults, but they
are still much more rufescent than the young of any other skua. The downy chick closely resembles
that of the Northern Skua. The bill is slaty, and there are light-colored areas on the legs and feet.
Oates (1901, 226) states that the eggs are indistinguishable from many eggs of the Northern
Skua. A common type is of grayish buff ground color, spotted and blotched with pale yellowish
brown and underlying pale purple. He records an example from Sea-lion Island, in the mouth of
the Rio Santa Cruz, Patagonia, which measures 73.7 x 52.1 mm. Paessler (1922, 444) gives dimen-
sions of two eggs from Santa Maria Island, Bay of Arauco, and one from Tierra del Fuego, as 69 x
51.6, 67 x 48, and 72 x 50.5 mm. One egg of a set originally containing two was collected by
1014 OCEANIC BIRDS OF SOUTH AMERICA
Beck from beneath an incubating male bird at Caroline Island, December 14, 1914. It is buff, with
only few and faint markings, and measures 69.2 x 59.5 mm.
Distribution: Breeds in Tierra del Fuego, the neighboring islets, and northward through the
Magellanic region of the west coast of South America to the Bay of Arauco, Chile; ranges north-
ward along the west coast to northern Peru and casually to the northern hemisphere; on the east
coast of South America it is said to range northward to Rio de Janeiro.
Throughout the length of the Humboldt Current the ‘‘Pajaro Ladrén’’
(thief-bird) is a familiar sight, harrying the boobies and Fork-tailed Gulls
(Creagrus) or fishing on its own account. Its white wing-patches and its beating
flight, which is far swifter than it appears to be, advertise the bird at long
range. In Peruvian coastal waters I have frequently seen the skuas pass so close
to my steamer or fishing-boat that their cinnamon breasts showed clearly. On
the other hand, very dark brown birds, of a type not ordinarily described in the
literature on this race, are by no means uncommon. I have seen a considerable
number of these in life, as well as four specimens among a total of about twenty-
three collected in the shore waters between Corral, Chile, and Callao, Peru.
The Humboldt Current is, of course, the migratory range rather than the
breeding range of the Chilean Skua, and yet I find by going through my note-
books and those of Mr. Beck that we have observed it in northern waters during
the whole period of its breeding season, as well as throughout the southern
winter. Characteristic records, from north to south, are as follows, birds col-
lected being noted by an asterisk: Lobos de Tierra Island, September 7; Sala-
verry, January 5; Mazorca Island, September 10, common; near Huacho, June
16, several; *off Callao, June 19 (MacFarlane (1887, 206) likewise reports the
skuas as abundant in the Bay of Callao during August and September, pursuing
the gulls); *off Cafiete, June 26; *off Cerro Azul, July 2; *off Pisco Bay, June 27-
29, numerous; *near the Ballestas Islands, October 19, two collected.
Along the coast of Chile the records of this skua are very numerous, and a
summary of the more important observations and collections has recently been
given by Hellmayr (1932, 414). Bullock saw an example in the coastal waters
of Mocha Island on December 14, 1932, but he did not find the species in resi-
dence. The northernmost definitely known breeding locality is at Santa Maria
Island, in the Bay of Arauco, where Paessler (1909, 101) has collected eggs.
The same author, however, has observed toward the end of December, at Punta
Angamos, Mejillones Bay, adults with young birds which he believed to be
not far from their breeding grounds. During the Brewster-Sanford Expedition,
Beck collected numerous examples off Corral during September and October,
and others within or near the harbor of Valparaiso during March. While he
was voyaging by schooner between Valparaiso and the Juan Fernandez Islands,
in December, 1913, he occasionally saw skuas up to distances of 150 kilometers
or more from the mainland coast. On June 6, 1914, he observed a number fish-
ing off Ancad, Chiloé Island, and from this point southward through the Magel-
lanic region they appeared frequently in his notes and in his bag of specimens.
Information is unsatisfactory regarding the occurrence of the Chilean Skua
along the east coast of South America. The only Brewster-Sanford specimen is
CHILEAN SKUA 1015
one captured at Rio Gallegos, Argentina, on June 3. Oustalet (1891, 172)
records four examples taken near the mouth of the Rio Santa Cruz in November,
and in the British Museum there are at least two specimens from the coast of
Brazil. It seems probable, however, that most of the migrant skuas that have
been taken along the Argentine, Uruguayan, and Brazilian coasts, are not of
this form, but are brown birds from the Falklands or from breeding grounds at
other Atlantic islands.
All of the Chilean Skuas collected by Beck within the Magellanic breeding
range were ‘‘pink-breasted"’ birds. It is therefore possible that the several dark
brown examples taken off the coast of Peru and central Chile, and listed in
line 2 of the table on page 1011, are representatives of some other form.
Unfortunately, the measurements of these specimens are of little aid in deter-
mining the matter. Ruddy birds, which had passed the physiological peak of
their reproductive rhythm, were taken in the Strait of Magellan toward the
end of February, and breeding examples were collected at London, Caroline,
and Vauverland Islands, to southward and westward of Tierra del Fuego, during
December and January. A male taken at Caroline Island on December 19 was
close to its nest, in which were two eggs ready to hatch, and two young just
out of the egg were found at Vauverland Islet, in the Gulf of Nassau, on January
6. Another nest, on the exposed top of a tiny holm off Caroline Island, is de-
scribed by Beck as a slight ring of grass. It contained two heavily incubated
eggs on December 14.
Chapman (1933, 371) speaks of the surprising number of skuas observed on
a motor trip in Tierra del Fuego about the end of January, and it thus seems
very curious that the species is not even listed in Crawshay’s (1907) compre-
hensive book on the birds of that region, especially since many earlier observers
have recorded it from the Strait of Magellan.
Judging by the plumage condition in our excellent series of specimens, the
greater part of the moult in the Chilean Skua takes place while the birds are on
their winter wanderings. Most of those shot within the breeding area are in
fresh and bright plumage. A June example from Callao, on the other hand, is
exceedingly worn and frayed, with quill replacement under way, the inner
primaries being quite new. There seems to be considerable variation in the
relative length of the jaeger-like middle pair of rectrices in this species, and
doubtless also in other skuas, a fact which makes the length of the tail perhaps
the least useful measurement for comparative purposes.
The habits of the Chilean Skua are similar to those of other forms more
fully described in the following biographies. Nicoll (1904, 47) writes,
This fine Skua was not uncommon in the Straits of Magellan and Smythe’s Channel. Several
times four or five birds followed us in to our anchorage. They were very wary, and I found that
the best way to procure them was to tie a dead Cormorant to a long string and let it drift away
from the ship. A Skua would soon discover it and come down to tear it to pieces; when thus
engaged it might be approached without difficulty.
Paessler (1922, 444) reports that the Chilean Skua is feared by practically all
other birds within its range, not excepting even the valiant Kelp Gulls. If a
1016 OCEANIC BIRDS OF SOUTH AMERICA
carcass is tossed overboard from a steamer, quickly to be surrounded by the
hungry gulls, they appear to make place respectfully as soon as a skua joins
the throng. The skua will attack even a cormorant, especially when the latter
has captured fish too large for it to swallow immediately, and will literally
take the prey out of the beak of the fisher if the latter does not dive at once.
Only the big Peruvian Pelicans seem to be immune from the attacks of the skua.
The swift South American Terns (Sterna hirundinacea) are pursued until they
eject the hard-won fishes from their throats and, as a rule, the pirate has little
difficulty in recovering such food before it reaches the water. Fish of various
unnamed sorts have been reported as the stomach contents of Chilean Skuas
collected in the Strait of Magellan and elsewhere. An example which I shot in
Pisco Bay, Peru, during October, was filled with anchovies, and a second taken
on the same occasion contained one silverside (Atherinidae) and several ex-
amples of a herring that the Peruvians call “‘machete’’ (Potamalosa notacan-
thoides). The latter were fragmentary, and are perhaps more likely to have come
by way of the gullets of boobies or cormorants than to have been captured by
the skua.
SOUTH POLAR SKUA
Catharacta skua maccormicki
Stercorarius maccormicki Saunders, 1893, Bull. Brit. Orn. Club, 3, p. 12 (Possession Island, Victoria Land,
latitude 71° 14’ S., longitude 171° 15’ W.).
Names: This species has also appeared in the literature under the specific name antarctica, and
an example which wandered to Japan was described under the name matsudairae.
Characters: Generally much paler than the Northern Skua and than other forms of the southern-
hemisphere skuas in fresh plumage, and without cinnamon-red sutiusion in the plumage. Ventral
surface usually pale buffy brown; neck conspicuously streaked with yellow or ‘‘golden’’ hackles;
white area at base of primary quills larger than in other forms. Nata] down unique in color, being
at first bluish gray instead of buffy.
A medium-sized skua, averaging slightly larger in most dimensions than C. s. chilensis or
C. s. antarctica, but with a relatively short tarsus. Notably smaller, except in wing-length, than
the pan-antarctic Brown Skua.
Measurements are recorded in the table on p. 1011. The average weight of four examples ob-
tained during the ‘Terra Nova’ expedition was 1224 grams. The body temperature of a South
Orkney example was 41.1° C. (Valette, 1906, 57).
Variation is wide, as discussed above and in the following text. In an average example de-
scribed by Saunders (1896, 321, pl. 1) the crown was clove-brown, the acuminate feathers of nape
and neck strongly marked with golden straw-color, the upper breast streaked with the same,
though in less degree; the remaining parts of the ventral surface gradually darkening to coffee-
brown on the abdomen; mantle, wings, and tail chiefly umber. Iris brown; bill, legs, and feet
black or blackish.
Fledglings show a bright blue patch of skin above the tibio-metatarsal joint. The newly
hatched chick is covered with gray-blue down, which subsequently turns brownish, apparently
as a result of absorption of oil from the subcutaneous tissues.
Eggs number two in a set, and closely resemble those of other skuas, being equally variable.
Oates (1901, 226) notes, in addition to dark examples, several of clear greenish blue ground color,
sparingly marked at the large end with a few smears and blotches of yellowish brown. 26 examples
from Cape Adare measured between 65.5 and 78.7 mm. in length, and between 47.7 and 52 in
breadth. Eggs from West Antarctica attributed by Gain (1914, 114) to the South Polar Skua
measured 65.5 x 48, 75 x 51.5, 74.5 x 52, and 71.5 x 41 mm.
SOUTH POLAR SKUA 1017
Distribution: Breeds apparently on all suitable shores of the antarctic continent, as in Ross
Sea, Weddell Sea, Queen Mary Land, etc., and also in the West Antarctic Archipelago northward
to latitude 65° S. or beyond. Winters chiefly at sea, and has been taken at the South Shetland and
South Orkney Islands; apparently wanders at times into the North Pacific.
The South Polar Skua was discovered during the first visit of the ‘Terror’
to Ross Sea, in January, 1841, being recognized at once by the members of the
British Expedition as quite different from the skuas they had observed at the
Auckland and Campbell Islands on the southward voyage (McCormick, 1884,
154). It undoubtedly holds the distinction of being the southernmost bird on
the globe. Amundsen encountered two at the inner edge of the Ross Shelf Ice,
in latitude 84° 26’ S., on January 9, 1912; and in December of the same year,
Mawson (1915, 2, 289) observed one which flew off in the direction of the pole
when he was in Adélie Land, more than 200 kilometers from the sea and at an
altitude of 1100 meters. Gain believes that two or three seen by Scott and
Wilson in latitude 80° 20’ S., more than 300 kilometers from open water, had
been attracted this enormous distance by the wind-borne odor of the blood of
a sledge dog slain some time before!
Little is known about the normal pelagic range of the South Polar Skua,
but it is highly probable that the season of its complete and definite winter
migration away from the breeding grounds is spent almost altogether in the
pack-ice.
In most parts of the far south, six or seven degrees of latitude seem to stand
as neutral ground between the range of the South Polar Skua and that of any
member of the genus inhabiting the ring of islands in the southern oceans. In
West Antarctica, however, this barrier largely disappears, for the pale Polar
Skua comes into such close contact with the Brown Skuas of lower latitudes
that the separation of the two, as they are recorded in the literature, becomes a
matter of considerable difficulty. Hamilton (1934, 174) discusses the question
as follows:
L. Gain (1915) [=1914] has stated that he found McCormick's Skua on Deception Island,
South Shetlands, where it was mixing with the Brown Skuas but was more numerous. He found
maccormicki nesting as far north as Admiralty Bay, 62° 6’ S., and mentions it as nesting at Port
Lockroy in Wiencke Island, 64° 4914'S. In the course of a number of visits to the South Shetlands
by Mr. A. G. Bennett and myself no specimen of maccormicki has been collected, and in my observa-
tion the whole area as far south as 65° of latitude is occupied by the darker bird, i.e. C. 5. antarctica.
The brown form is abundant and nests at Deception, and while Gain records having seen it
as far south as Wiencke Island at the south end of the Belgica Straits he states that it did not nest
in the Straits. In 1922, however, I found that Port Lockroy had become a nesting site.
It may be suggested that the Brown Skua, which is slightly larger than maccormickt, favoured
by the abundant food supply derived from the extensive whaling operations subsequent to 1909,
had succeeded in ousting maccormicki from its former breeding places in the South Shetlands, at
least as far south as Port Lockroy. It is well known that the skuas are most combative birds and
even given to cannibalism at times.
Now I have already shown that absolutely typical specimens of maccormicki
have been collected by Mr. Bennett himself in this very region. These are the
birds recorded in line 4 in the table on page 1011. One of them was a female
1018 OCEANIC BIRDS OF SOUTH AMERICA
with enlarged ovaries, taken at Deception Island on December 11, 1921, and
the second a female from Wilhelmina Bay on the Danco coast, taken on Feb-
ruary 8, 1922. Furthermore, Gain has distinguished between the South Polar
Skua and the Brown Skua in a manner that cannot be controverted. He sum-
marizes the division in the west antarctic ranges of these two forms as follows:
the Brown Skua nests at the South Shetlands, on the opposite coast of Louis
Philippe Land, and elsewhere to northward of De Gerlache Strait, the northern
end of which is in approximately latitude 64° S. The South Polar Skua nests
at the South Shetlands, along the shores of De Gerlache Strait, on the islands
of Wiencke, Booth-Wandel, and Petermann, and along all coasts of the archi-
pelago to southward. The newly hatched young of the South Polar form are
very different in appearance from those of any other group of skuas, for they are
of slaty gray color instead of being buffy. Gain (1914, 115), in describing this
coat as ‘‘un duvet gris bleuté,’’ shows positively that he distinguished between
the South Polar Skua and the Brown Skua.
It thus appears that the breeding ranges of the two forms are in such close
contact as to suggest that there must be two fully distinct species. In consider-
ing this matter, however, attention should be paid to the possibility of recent
and more or less artificial changes in distribution, due to whaling operations.
In more northerly parts of West Antarctica, the Polar Skua has been observed
at Laurie Island of the South Orkneys during November and December, the
birds being readily distinguishable from the native skuas by their smaller size
and lighter coloration (Valette, 1906, 57). An example was shot here on
November 11, 1904, and examined by members of the ‘Scotia’ expedition who
were entirely familiar with the breeding birds of the island (Brown, Mossman,
and Pirie, 1906, 348).
In the collection of the American Museum this species is represented by the
two specimens from West Antarctica already referred to, by examples obtained
in the Weddell Sea region by Bruce and by Filchner, and by nine birds collected
near the eastern end of the Ross Shelf Ice during the first Byrd Antarctic Expe-
dition. The examples from opposite coasts of the antarctic continent are not
distinguishable in size or pattern, as has already been reported by Lowe and
Kinnear (1930, 122). It is worth remarking, moreover, that animals of high
antarctic latitudes rarely exhibit racial differentiation; they are circumpolar in
the fullest sense of the term, and doubtless have practically continuous breeding
ranges around antarctic coasts in so far as physiographic conditions permit.
Measurements of the adult breeding specimens from Ross Sea are listed in line 3
of the table on page 1011.
The following data on the life history are taken chiefly from the accounts of
Gain, Levick (1914, 125), Bernacchi (1901, 204), and Wilson (1907, 36).
When the skuas return from their migrations to their breeding grounds in
West Antarctica, most of them are in relatively dark plumage which, however,
becomes rapidly bleached by the actinic rays of the sun passing through a
practically dustless atmosphere. Similar action of such light has already been
referred to, in connection with its effect upon antarctic penguins. By January,
SOUTH POLAR SKUA 1019
the prevailing coloration of many of the birds is what Gain expressively calls
‘chamois trés clair,"’ or even whitish. Moult and replacement of feathers in
this form immediately succeed breeding activities, and with this change the
birds again take on a somewhat darker aspect.
On all antarctic shores the skuas seem to begin to arrive from the north in
late October, their numbers increasing very rapidly after the appearance of the
first penguin eggs in early November, so that by the end of that month the
entire population is back at the breeding ground. The nesting of the skuas at
Cape Adare has been observed to begin by November 12, the chosen sites being
mostly on small headlands or in screes overlooking penguin colonies. The
French naturalists found an aggregation of upwards of 200 pairs on a sunny,
northern exposure of Petermann Island, extending from the shore to an altitude
of 130 meters. The nest itself is nothing more than a scrape, without lining,
and is often one of several that the hen makes before laying. Eggs have been
found at Cape Adare as early as November 29, but most records for West Antarc-
tica are a month or more later than this, although Gain reports that he pro-
cured the first eggs at the beginuing of December and the first hatched chicks
a month later. Two eggs constitute the whole set, there being an interval of
two days between the laying of each. If the first set is removed from a nest, a
second will be produced, but not a third. If, however, only one egg is taken,
the birds will merely continue to incubate the remaining egg, for an empty nest
is the essential stimulus to relaying. Incubation lasts about four weeks.
The newly hatched chicks quarrel in the nest from the date of hatching;
therefore they tend to separate from one another, as a result of which one of
the two is sure to ramble outside the field of conscious parental protection,
whereupon it is equally certain to be pounced upon and killed by a hungry
neighbor or by its own deluded parent. The adults are little given to brooding
their young or otherwise guarding them from the elements and, according to
Wilson, less than fifty per cent of the skuas survive beyond early infancy in
these regions of rigorous environment. For one reason or another, the parents
themselves very frequently eat their own young. Gain found many chicks thus
destroyed—not entirely devoured, but with their eyes and entrails picked out.
Moreover, it is a common occurrence for half the offspring to be eliminated even
before hatching, through the swallowing of one egg by a parent.
Young skuas are fed not from mouth to mouth but from the ground, and
before they are many days old they learn to pick about, in the manner of domes-
tic chickens, among the pebbles near their nests. Gain says that the adults
merely deposit fragments of fish and crustaceans close to the nest, allowing
the chicks to help themselves. By the end of February, the oldest young are
capable of flight, and the beginning of departure for the north takes place in
early March.
At the South Shetlands, according to Gain, the skuas not only hunt for fish
and crustaceans, and rob such birds as cormorants of their spoils, but they also
do not disdain to eat seaweed, moss, and lichens, when other food fails. They
are quick to take advantage of the slaughter of whales, and to gobble up the
1020 OCEANIC BIRDS OF SOUTH AMERICA
placenta of the newly born Weddell and crab-eater seals. The bulk of their
food here as elsewhere, however, comprises the eggs and chicks of various sorts
of penguins. Eggs are stolen whenever left exposed, and can be picked up almost
without a pause in the skuas’ flight. In victimizing young penguins, they
attempt to cut one off when it is somewhat separated from its fellows, con-
triving to urge or drag it little by little away from the center of population,
and then strike it on the head and gradually worry it to death, ending by pick-
ing out the eyes and making two holes in the back through which the tissue
of the kidneys can be extracted. Hundreds of bodies of young penguins, tram-
pled into the soil, show evidence of these particular mutilations and can be
found about the edges of all the colonies. There is, indeed, no defense against
the appetite of the skuas except a fitness and willingness to fight back. They
are as ready to eat their own kind as any other species of animal; Levick has
given a ghoulish description of how sick skuas are spotted and tormented by
their own fellows, being free from actual attack only so long as their lessening
strength still enables them to fend off the unhurried but inexorable brethren.
The great strength of the Polar Skuas enables them to carry off chunks of
food heavier than themselves. They are, of course, noisy when competing and
feeding together, the sound of their bickering being likened by Levick to the
medley of a flock of farmyard ducks. Besides such chatter, they have a repertory
of gull-like shrieks and screams.
At the end of summer the skuas leave the Antarctic Archipelago; the last
birds to depart from the Petermann Island district were noted by members of
the French Expedition between April 15 and 20. During the winter absence,
when the birds spend most of the time in the pack-ice, they secure the better
part of their food through what might be called honest efforts, instead of by
means of highway robbery and despoliation. At sea they appear in the main
to subsist upon the abundant euphausians of the ice-floes, the same organisms
which support the wintering Adélie and Emperor Penguins, the Snow Petrel,
and the crab-eater seal.
FALKLAND SKUA
Catharacta skua antarctica
Lestris antarcticus Lesson, 1831, Traité d'Orn., livr., 8, p. 616 (Falkland Islands).
Names: Sea Hen or Port Egmont Hen; ‘‘Gaviota Parda’’ is an Argentine name. Synonyms of
the specific name include those applied to other skuas such as catarractes, besides which the sub-
specific name falklandica has also been applied to this form.
Characters: Smallest of the skuas; of highly variable plumage, but most closely resembling
the Brown Skuas of the pan-antarctic islands. Further discussion of feather characteristics is
reserved for the text below.
The following measurements form the basis of those listed on p. 1011, but are here segregated
as to sex. They all refer to resident, breeding adults from the Falkland Islands:
10 males: wing, 366-387 (376.4); tail, 139.6-154.5 (145.8); exposed culmen, 46.5-50.3 (48.7);
tarsus, 64.3-70 (66.9); middle toe and claw, 72.2 mm.
6 females: wing, 378-398 (384.6); tail, 140-156.7 (151.7); exposed culmen, 47-50.8 (48.9);
tarsus, 64.7-69.6 (68.2); middle toe and claw, 73.9 mm.
The natal down is buffy, like that of all skuas save Catharacta skua maccormicki.
FALKLAND SKUA 1021
The eggs, according to Vallentin (1924, 305), appear to be of two phases, of which one is dark and
“‘normal,’’ while the other is pale bluish white, with a few brown spots. Eggs of the latter type are
particularly common at Carcass Island, but have been found also at Port Egmont and elsewhere.
Five sets of two, taken by Beck at East Island, December 10, 1915, may be described as follows,
with reference to his field numbers:
135. From one of about 20 nests within a small area. Eggs very different in both shape and
color, although similar in the pattern of their markings. One of them has a ground color close to
grayish olive, while the other and smaller is buffy brown. The overlying marks are irregular dark
brown spots, varying in size from tiny points to blotches with a diameter of 15 mm. or more. The
blotches buried beneath the surface of the shell are, of course, paler. 68.1 x 50.5; 63.7 x 58.3 mm.
134. Generally resembling the preceding set, but with more pronounced differences of form,
ground color, and pattern between the two eggs. The markings on one include heavy scrawls in
addition to more or less regular blotches. 72.3 x 49.1; 67 x 58.7 mm.
133. In ground color the most dissimilar set of the series. One is pale pea-green, with sparse
spots which are likewise pale because the pigment underlies the limy coating of the shell. The
second is grayish olive, with brown blotches on the surface. 69.9 x 59.1; 69.1 x 50.6 mm.
137. Grayish olive, one with a distinctly more brownish cast than the other; spotting rather
sparse and pale. 71 x 50.1; 70.5 x 49.9 mm.
138. Of only slightly different ground color and rather heavy brown blotching, but dissimilar
in shape, one being rotund and the other considerably pointed at the smaller end. 74 x 50.6;
73 x 53.2 mm.
Distribution: Known as a breeding bird only from the Falkland Islands, from which it ranges
northward along the South American coast to beyond the latitude of Cape Frio, Brazil. (The
resident skuas of Gough Island and Tristan da Cunha appear to represent a distinct race, and to
have closer affinities with the skuas of South Georgia than with those of the Falklands.)
The Falkland Skua, as shown by the statistical studies of Hamilton and the
measurements of 16 Brewster-Sanford specimens listed in line 5 of the table on
page 1011, is a very distinct race, most closely related neither to the Chilean nor
to the South Polar Skua, but rather to the ‘‘brown’’ birds of the circumpolar
pan-antarctic islands. It has, however, a wide range in coloration. Our Falk-
land specimens exhibit, indeed, every phase between very dark brown birds
and others as pale as the lightest from South Georgia or elsewhere. Many of
them also have pronounced golden hackles on their necks. Even in the lightest
examples, however, the dorsal surface is always somewhat streaky or spotty,
and no Falkland bird shows the clear chamois color of the head and mantle
that characterizes certain South Polar Skuas, even though a few of them do
have a vinous belly practically indistinguishable from that of maccormicki.
Rufous feathers, similar to the typical plumage of chilensis, are often present to
a limited degree in the backs and breasts of Falkland Island specimens, as pre-
viously noted. But Falkland birds are not larger than the South Polar Skuas,
as stated by Bennett (1920, 256). On the contrary, the measurements in my
table show that they are definitely smaller in every dimension except length of
the tarsus. The Falkland Skua is, in fact, the smallest of all known forms of
the genus, the difference being particularly striking when Falkland birds are
compared with the larger representatives from other islands of the Scotia Arc
or from those that extend eastward toward the New Zealand region between
the 40th and 60th parallels of south latitude. Even the birds of Tristan and
Gough are larger than those of the Falklands.
It is clear from what I have written above that the names and identities of
1022 OCEANIC BIRDS OF SOUTH AMERICA
skuas captured along various parts of the South American coast have been badly
confused. Most of the published records have a quite uncritical basis, so that
they give us no dependable clue as to the actual place of origin of migrant birds.
The fact is emphasized by two skuas collected by Beck at Mar del Plata, Argen-
tina, during early October, 1914, and listed in line 9 of the table on page 1011.
These birds are Brown Skuas bearing a general resemblance to certain Falkland
specimens; nevertheless, they show by their measurements that they are of
quite different provenance. The point of this comment is that we shall know
Paes nothing about the pelagic range of Falkland Skuas until more com-
prehensive collecting has been followed by far more thorough systematic work.
It is therefore of special interest to point out that a skua which I shot from the
brig ‘Daisy,’ on October 26, 1921, in latitude 21° 40’ S., longitude 34° 12’ W.,
is absolutely indistinguishable in appearance and measurements from Falkland
birds. This specimen is listed in line 6 of my table. The point on the ocean at
which it was taken lies southeast of the Abrolhos Islands, and about halfway
between Cape Sao Thomé and the island of South Trinidad.
Birds listed under the name of the Falkland Skua have been recorded from
the Patagonian coast (Dabbene, 1918, 218), from the eastern entrance of the
Strait of Magellan in mid-May (Paessler, 1909, 101), and from the coast of
Buenos Aires between the end of April and the end of August. At the last
locality they are commonly observed in pairs, or in bands of a half dozen or
more (Daguerre, 1922, 261). Such observations may well refer to Falkland
birds, but in view of the character of the two specimens shot by Beck at Mar
del Plata, there can be no certainty about it.
During the course of the Brewster-Sanford Expedition, Beck collected about
20 specimens of the Falkland Skua, and on December 10, 1915, he took at East
Island five sets of fresh or very slightly incubated eggs.
At the Falklands the skua is known by the nearly universal sailor's name of
Sea Hen. The birds arrive from their pelagic wanderings during the first half
of October, and remain until April, by which time all but stragglers have
departed. They make their nests as a rule on relatively high ground and, al-
though they are not deliberately placed close together, a community of interests
supplied by neighboring rookeries of gulls, penguins, or cormorants usually
results in a sort of colonial aggregation of the skuas. The foundation of the nest
is little more than a scrape in the soil, but this is frequently lined to a slight
extent with grass. Two eggs, or rarely three, are laid late in November or
during the first half of December, and a month later the fluffy balls of buffish
down hatch out.
Although the Falkland Skua is a wary bird during part of the period of its
residence, it never hesitates to attack a man or dog boldly during the nesting
season. The birds scream harshly and swoop at any intruder that comes near
their young. The sheep dogs are much afraid of them and learn to throw them-
selves upon their backs when the skuas attack, and many human beings at the
Falklands have been stunned by the blows of the birds after they had unwit-
tingly approached too close to a nest (Vallentin, 1924, 305).
FAG RBDAN D- SKU A 1023
The height of the breeding season comes about Christmas time, and Cobb(1933,
50) writes as follows of the dash and verve of the Falkland Skuas at this season.
It means a merry Christmas for any human being or dog who dares to approach anywhere in
their vicinity, either on business or for pleasure; if the latter, it is mostly on the Skuas’ side.
Gathering sheep for shearing in a Sea~Hen-infested area is no joke.
These birds are always labouring under the delusion (which is not always a delusion, by the
way) that all men and dogs seen are after their little ones. This makes them croak with rage and
sail at top speed straight for the head of the unfortunate dog or man—which they miss by inches
as a rule, but occasionally hit. If they hit, it is worse than unpleasant, for they are exceptionally
strong on the wing and are capable of making one see stars by daylight with their terrific biffs on
the back of one’s head.
Men have been knocked down by them and dogs so terrified that they take refuge from them
under the friendly lee of the horse’s heels, knowing that it is the highest point that will be struck,
if any. They refuse to get on with their job of gathering the sheep, which in itself is a crime, and
the beginning of more troubles for the Sea Hen family.
At times the air is so full of these birds that the only way to progress at all is to lash a sheath-
knife to a stick and hold it above one’s head. There is no second innings for the Skua that strikes
the knife.
A favourite game played by a pair of Sea Hens is to rake you fore and aft simultaneously.
Starting a savage swoop almost synchronising with mother’s, father will do his best to scalp you
from the front, while his better half tries to make your back hair stand on end from the rear,
which is a hair-raising game in more senses than one, should they succeed in knocking off your hat.
Cobb describes, furthermore, the raid of a skua into a larder of gull eggs:
At one rookery the writer watched a Sea Hen arrive, chased by a pair of pied Oyster-Catchers;
the gulls arose in a body, chortling, laughing, and screaming, and joined in the pursuit, leaving
all their eggs uncovered. The Sea Hen dodged and sailed through the whole lot backwards and
forwards, enjoying the fun—as an international footballer might run through a crowd of boys—
although a gull tweaked it by the tail, while the Oyster-Catchers screamed at and worried it.
Finally, with a long, low, unexpected swoop, it carried off an egg in its bill.
In addition to pilfering from the penguin, shag, and gull colonies, the Falk-
land Skuas are of course always ready to pick up small petrels or young birds of
any kind. Cobb writes that they bully the shags into disgorging their break-
fasts, and that a skua will start eating goose eggs a yard from a grazing horse's
nose. When a sheep is being skinned, they will assemble and wait to inherit
the carcass, and they are quick to attack lambs or sickly full-grown sheep.
As scavengers they rank, in fact, with the local Turkey Vultures. Beck records
seeing groups of them sitting among the Kelp Gulls near a slaughterhouse on
the shore of Stanley Harbor. At some of the outlying islands of the Falklands,
he found that the tables had been turned on the skuas, which were regarded by
the inhabitants as game birds. Eighteen or more of them were shot and eaten
by the residents, for example, during his visit to Sea Lion Island in December.
BROWN SKUA
Catharacta skua linnbergi
Catharacta antarctica linnbergi Mathews, 1912, Novit. Zol., 18, p. 212 (New Zealand seas).
In adopting this name for all the circumpolar Brown Skuas, except the race of the Falkland
Islands, I am following the conclusions of Hamilton (1934, 173). The following additional races
have, however, been described:
1024 OCEANIC BIRDS OF SOUTH AMERICA
Catharacta lonnbergi clarkei Mathews, 1913, Birds Australia, 2, p. 494 (South Orkney Islands).
Catharacta lonnbergi intercedens Mathews, 1913, Birds Australia, 2, p. 494 (Kerguelen Island).
Names: The representatives of this form have been variously called Sub-Antarctic or Antarctic
Skuas, or have been known by the names of their respective insular localities; Sea Hen and Sea
Hawk are appropriate sailors’ names; synonyms of the scientific name include most of the names
which have been applied to other forms.
Characters: Largest of the skuas, the size character showing in every dimension, but par-
ticularly in the length and bulk of bill and tarsus. Prevailingly “‘brown”’ in plumage, #.e. with a
minimum of ‘‘chamois-color’’ and of cinnamon, but subject to wide individual variation, as
described in the following text. Some specimens, even in fresh plumage, are very whitish on both
mantle and ventral surface.
Measurements are listed in lines 7 and 8 of the table on p. 1011. The following refer to breeding
adults of each sex from South Georgia:
6 males: wing, 401-416 (407); tail, 153.5-162.4 (156.9); exposed culmen, 54.3-58.2 (56.5);
tarsus, 70.8-79.3 (75) mm.
8 females: wing, 397-416 (407); tail, 143.4-157 (150.5); exposed culmen, 53.5-56.7 (55.5);
tarsus, 72.8-79 (75.3) mm. ;
The length of middle toe and claw in 11 examples of both sexes is 76.8-84 (78.7) mm.
Birds from the South Shetlands are of identical size and appearance. Valette (1906, 56) reports
that the length in the flesh of a Brown Skua from the South Orkneys was 63 cm.; its wing-spread
was 150 cm., and its intestines measured 95 cm. It had a bifurcated tongue.
The juvenal plumage in this race, according to my own abundant observations and the testi-
mony of other observers in various parts of the pan-antarctic region, is nearly uniform brown,
except for the white wing-patch; pale or rufescent feathers are lacking. The natal down is buffy.
The dimensions of three South Georgian eggs, as recorded by Szielasko (1926, 38), are 77 x 53,
76 x 52, and 73 x 48 mm. In the single instance when three eggs were found in a nest, one was
infertile.
The only surviving example of a set of two eggs which I collected at Cumberland Bay,
South Georgia, December 3, 1912, is somewhat pointed at the smaller end, of grayish olive
ground color, rather generally though sparingly flecked with small spots and blotches, most of
which are light brown or pale purplish because they lie beneath the surface of the shell. A few
spots of external pigment are umber. The egg measures 74.9 x 52.8 mm.
Distribution: Circumpolar at islands lying in the Antarctic and Sub-Antarctic Zones of surface
water, except for the Falklands and probably Tristan da Cunha. Breeding in the West Antarctic
Archipelago to about the 65th parallel of south latitude, and at such antarctic islands of the
Scotia Arc as the South Shetlands, South Orkneys, South Georgia, and presumably the South
Sandwich chain. To eastward this race occurs at Bouvet (Vanh6ffen, 1901, 311; Reichenow,
1904, 349), the Prince Edward and Crozet groups, Kerguelen, Heard (Moseley, 1879, 230), and
perhaps St. Paul; also at the following islands to southward and eastward of New Zealand:
Stewart, Chatham, Snares, Auckland, Campbell, Antipodes, and Macquarie.
Bennett (1920, 256) agrees with Hamilton in stating that there are two distinct types of Brown
Skuas at the South Shetlands, aside from the South Polar Skua. 1 have no specimens which would
throw further light upon this question, and its solution must await study of adequate material.
Might it be possible, however, that the small skuas of the Falklands have begun to migrate into
the Antarctic since the beginning of modern whaling?
Hamilton's detailed study of measurements and plumages of more than a
hundred Brown Skuas taken in all parts of the circumpolar area shows that
data are not yet adequate for distinguishing several subspecies from the pan-
antarctic ring of islands. To be sure, he arrives at the conclusion that specimens
from the New Zealand region average barely larger than those from New-World
islands. The figures I have listed in the table show, however, that the bills,
tarsi, etc., of certain specimens from South Georgia are practically as large as
BROWN SKUA 1025
the maximum among New Zealand birds, while the length of the culmen in a
skua collected at Mar del Plata, Argentina, is greater than that of any example
recorded from New Zealand.
During the South Georgia. Expedition of 1912-1913, I became extremely well
acquainted with the Brown Skua, which has left, I believe, a more vivid im-
pression in my memory than any other bird I have met. The skuas look and
act like miniature eagles. They fear nothing, never seek to avoid being con-
spicuous, and, by every token of behavior, they are lords of the far south. In
effect, they are gulls which have turned into hawks. Not only are they the
enemies of every creature they can master, living almost entirely by ravin and
slaughter, but they also have the appearance of a bird of prey in the general
color of their plumage, the pointed, erectile hackles on the neck, the hooked
bill, and the long, sharp, curved claws, which seem incongruous on webbed
feet. They are tremendously strong, heavy, and vital birds which, in the air,
look massive rather than speedy. It is therefore somewhat surprising to learn
that they can overtake in free flight such swift, long-winged petrels as the
Shoemaker (Procellaria aequinoctialis). Energy is apparent in every movement
of the skua—in its rapacity, in the quantity of food it can ingest within a few
moments, and in the volume and continuousness of the screams that issue from
its throat. Doubtless, its physiological processes are relatively rapid, even for
the group of vertebrates which has the highest metabolic rate. It is therefore
not surprising that Valette (1906, 56) found the skua’s body temperature of
42.3° C. (108.1° F.) to be higher than that of the other warm-blooded animals
at the South Orkney Islands.
The wide range in color of South Georgian Skuas has been attested by
Hamilton and by Matthews (1929, 581), and is confirmed by my own field notes
as well as by the thirty or more specimens I have examined. The variation on
this single island is probably as great as that shown by Brown Skuas through-
out the whole geographic range between West Antarctica and New Zealand.
But even the grayest of the South Georgia birds, which are nearly white on
their backs, never show the clear ‘‘chamois-skin’’ which so often characterizes
the head and mantle of the South Polar Skua. As Hamilton has pointed out,
feather tissue deficient in pigment abrades much more rapidly than feathers or
parts of feathers which are dark. For this reason, the plumage of Brown Skuas
often bleaches and wears away with great irregularity, so that the birds become
ragged and frayed in an asymmetrical pattern. Rufous and cinnamon feathers,
similar to the typical plumage of the Chilean Skua, appear sporadically among
South Georgian birds, just as among skuas of the Falkland race. So far as my
field observation goes, the plumage that immediately succeeds the down is
always of a uniform dark brown. Therefore, while the very light new feathers
of some skuas are probably not indicative of advanced age, they at least appear
only subsequent to the post-juvenal moult. All of these circumstances are
matched among the few South Shetland specimens I have seen, and they agree
with published descriptions relating to the resident skuas of the South Orkneys.
The South Georgian Skuas, like those of other parts of the Scotia Arc and
1026 OCEANIC BIRDS OF SOUTH AMERICA
of the Falklands, are migratory birds, returning to their home island at the
commencement of the southern spring, and going to sea again before the end
of April. The first arrivals have been observed toward the close of August, but
the largest influx is apparent about the middle of October, preceding which
date, according to Lénnberg (1906, 58), very large numbers of skuas are to be
observed at sea to northward of latitude 47° S. On November 14 at Kerguelen,
Werth (1905, 570) saw pairs in pursuit flight, which was probably part of the
courtship performance. Nesting commences in November and the eggs, which
usually number two, but sometimes only one and still more rarely three, are
found from the middle of the month until well into December. Two eggs, laid
about the end of December, are reported from the more southerly latitudes of
the South Orkney and South Shetland Islands.
The first eggs at South Georgia were seen by the long-resident members of
the German Expedition on November 20, and the first young about Christmas
time (von den Steinen, 1890, 259). On December 31, 1912, however, I found at
Cumberland Bay several nests containing large downy young, indicating a con-
siderably earlier egg-laying period. At Kerguelen, the period of incubation,
as determined by Studer (1879, 107), is about five weeks, the duties thereof
being shared alternately by both parents (Loranchet, 1916, 306). A creditable
nest of tussock grass, moss, bits of seaweed, and other vegetable material is
commonly formed on a flat mossy area of a headland. The chosen site may be
at any altitude from just above sea level to 700 meters. It usually overlooks the
ocean and is rarely, if ever, far from penguin colonies or from the subterranean
breeding grounds of petrels, both of which are regarded by the skua as its
private larder. )
When I reached South Georgia in late November, most of the skuas already
had eggs. The birds were standing or squatting everywhere on the summits of
hillocks and promontories, or soaring in circles during periods of the day that
were quiet and sunny. At such times they looked more than ever like broad-
winged, Buteonine hawks. When I walked along the beaches, the skuas feeding
close to the water's edge would pay little attention to me. As a matter of fact,
when they stepped out of the way, their manner seemed rather one of courtesy
than of caution. However, there was one particular gray skua which attacked
me without provocation on several different days along the beach of the Bay
of Isles. The terrain was of such a nature that there could be no nest near-by;
moreover, I never saw this bird's mate. Yet, when I was least suspecting, I
would be startled by a furious rush of wings, and would dodge instinctively
just in time to let the gray skua skim over my head. After two or three such
dashes, it would make off. As soon as I turned up into the grasslands behind
the shore, however, I would never be left long in doubt regarding my invasion
of breeding territory. The old birds would become quite frenzied as their nest
was approached, and would swoop at me in the well-known manner, varying
their attack by standing on the ground close by, with wings pointed straight
upward and heads downward, and screaming at the tops of their lungs. Atter
the young birds had hatched, the parent skuas became more ferocious than
BROWN SKUA 1027
ever. They would begin the attack when I came within 100 meters of the nest,
continuing it until I had passed at least that far out of the neighborhood. On
one occasion when I was banding a chick in the nest—he screaming lustily all
the while—both parent birds actually struck with the quills of their wings
the barrels of the gun I held above my head as a protection against their assaults.
Seeing the cranium of a whale-bird lying on the grass, I offered it to the infant
skua, which swallowed it with evident satisfaction and immediately ceased
its clamor.
By subsequent experience I found that it was also possible to distract the
fixity of the old birds’ attention by supplying a distinct new stimulus. Thus, if
I should toss on the ground a bit of food, the latter would claim at least the
temporary attention of the parents. On one occasion a pair of skuas immediately
ceased their attack when | shot a South Georgian Pipit, a small land bird which
frequently nests within the skuas’ territory, and which is apparently not sub-
ject to their attacks. On this occasion they did not find the dead pipit, but
within a few moments they became entirely absorbed in the red cartridge shell
ejected from my gun. Each skua picked it up, and one of them carried it about
in its bill for some time. These birds may have had sufficient experience to
associate the report of guns with the possibility of obtaining a prize, for on
other occasions skuas succeeded in stealing and carrying off examples of teals,
terns, and petrels shot by members of my party.
The ease with which a certain train of behavior may be broken is very sug-
gestive in connection with the usual lack of intelligence, as opposed to purely
instinctive behavior, among birds. Sérling, as recounted by Lonnberg, examined
three eggs of one pair of South Georgian Skuas and then returned two to the
nest, placing the third on the ground a short distance away. As soon as the
first parent settled beside the nest, it ate the egg which had been removed, and
then snuggled down to brood the other two. On another occasion, Sérling
interfered with the natural sequence of an adult skua’s reactions to the extent
of assisting a hatching chick out of the eggshell. The parent, which had been
thus disturbed by the well-meant offices of man, devoured its offspring the
instant it returned to the nest. While the South Georgian Skuas in rare in-
stances rear both of their chicks, it is far more common for only one to attain
even the fledgling stage. I suspect that the destruction of the other is accom-
plished much more often by its own parents than by neighbors, to which Gain
charged the death of the young South Polar Skuas. What happens is doubtless
very much as follows: so long as the chicks remain within the nest-bowl, they
are regarded by the parents as rightful occupants. Sooner or later, however,
and usually within a few days after hatching, one or both will cross the thresh-
old to pick about over the surrounding territory. When a parent returns with
food, the chick remaining in the nest, or one of the two outside the nest,
awakens the feeding response, and food from the gullet of the adult will be
ejected on the ground beside it. This reaction being completed, the other and
less fortunate offspring is likely to be regarded as a wholly extraneous object—
in other words, as something to be eaten.
1028 OCEANIC BIRDS OF SOUTH AMERICA
The incident of the skua which ate its chick that had been helped out of the
shell may signify that the parent needs to be conditioned to the presence of an
active young bird by having the latter hatch beneath it. Furthermore, it seems
likely that conditioning to a single chick is as far as the process can usually go,
and this fact accounts equally for the eating of the second. We might put the
matter otherwise by saying that the reactions of the skua are in somewhat
unstable equilibrium with relation to two chicks; one is reasonably safe, but
two produce a conflict between a parental response and a desire to eat and,
sooner or later, the latter wins out.
Whatever the biological meaning of this type of infanticide, it no doubt
works out as highly advantageous to the general balance of nature. The skuas
are already extremely abundant as well as intolerably aggressive, and a further
increase in their numbers, due to the rearing of a much larger proportion of
chicks, would doubtless lead to overpopulation.
When the chicks first hatch, they lie closely in the nest and show no alarm
in the presence of potential danger. After they are several days old, however,
they will slip off at the first sign of a human intruder and crouch flat in the
nearest hiding place. Although they regularly wander a short distance away
from their homes for other reasons also, they always return to them, the nest
remaining a focal point in the life of a family until the young are fledged. At
the beginning of their flight period, they exercise a good deal by jumping into
the air, facing the wind, accompanying the performance with a plaintive
whistling note. At South Georgia I saw the first flying young on February 26,
and within a few days thereafter they began to be common. All such were in
uniform dark brown plumage, without a trace of yellowish or grayish teathers,
a fact noted likewise by Pagenstecher and von den Steinen. The young remain
dependent upon their parents for a considerable period after they begin to fly,
and they keep in close touch by means of their whistling calls. They fly strongly,
but when high winds are blowing they seem to experience much difficulty in
alighting, or even in standing on the rocks in the teeth of the blasts. The older
birds, however, are quite able to take care of themselves in any weather. Before
taking flight trom the ground, the skuas often hop along on both feet for a few
steps. Their flight is surprisingly fast, their wing-beats being somewhat more
rapid than those of most gulls. Not only do they soar, but sometimes they
allow themselves to drift backward in quiet fashion as they face the wind.
When they alight on the ocean, they always hold up their pinions for a time.
If wounded on the water, they will not try to swim offshore in the manner of a
typical sea fowl, but will rather make every effort to gain the nearest rocks.
The young leave South Georgia along with the bulk of the old birds about
the end of April. A few skuas, however, linger later; the members of the Ger-
man Expedition saw some well into June (Pagenstecher, 1885, 24). At Kergue-
len, which has a generally milder climate than South Georgia, skuas are present
all the year round, although much rarer in winter than at other times(Loranchet,
1916, 306). Menegaux (1907, 465) states that in West Antarctica the young
skuas are the first to migrate away from the homeland. They leave the islands
BROWN SKUA 1029
of the Antarctic Archipelago about the beginning of March, and do not return
before spring.
During the middle part of the day, especially when the sun is shining, the
South Georgian Skuas bathe in the relatively warm water of pools in the flat
grasslands. They shake and splash, and ruffle out their feathers, quite in the
manner of song birds at a fountain. The edges of ponds and glacial streams
seem to be accepted as neutral ground by the members of mated pairs not engaged
at the moment in incubation. It was not uncommon to see forty or fifty skuas
associating in the ponds of grassy glens about Cumberland Bay, or even to
meet the birds when they were flying over the low mountain passes leading
toward such places. These retreats are also favorite sleeping quarters after the
breeding season is finished. On March 4, at Possession Bay, I found a great
number of skuas just after dusk, each balancing on one foot at the edge of a
runnel, most of them with the bill tucked under the wing coverts.
One usually thinks of the skuas’ voice as a scream, because they make their
most impressive picture when they stand in angry or defiant attitude, their
wings held upright in the posture of those on ancient Norse helmets, and pro-
test with ear-splitting cries. A quieter more conversational note, however, is
much like the quacking of a duck and, before I became accustomed to it, I
looked for a South Georgian Teal whenever I heard it. I do not remember ever
hearing a skua cry out after being wounded by a shot.
The manner in which skuas quickly gather about one of their stoical, injured
confréres, however, implies neither sympathy nor altruism. It is a good deal of
a mystery, indeed, as to what sense so quickly leads them to assemble ominously
near a hurt or sickly member of their own tribe, to follow it about relentlessly
if it can still fly, and to stand by with complete patience until the victim suc-
cumbs, or until the moment for the coup de grace arrives. Hall (1908, 8) states
specifically that skuas have been known to kill and eat their own wounded
mates. I found that they would devour the flesh of their fellows which I had
skinned as avidly as any other sort of meat. Von den Steinen carried a skua
chick to a distance from its own nest, and when he put it on the ground it was
instantly attacked by all the old birds in the neighborhood. Brown, Mossman,
and Pirie (1906, 178) observed a battle almost to the death between two skuas
on an ice-floe at the South Orkneys, while a third bird looked on from an ad-
jacent hummock. The date was November 9, which suggests that the struggle
may possibly have been connected with courtship. Such contests in nature are
rarely fatal, since supremacy is the only point to be established. In this instance,
however, the beaten skua, while too fatigued to defend itself further, was torn
to pieces by a Giant Fulmar.
The diet of the skuas is, of course, not confined to other birds. They hunt
along the beaches for food cast ashore, and even capture fish that rise to the
surface, though I have never seen one dive for food. Werth (1925, 570) reports
that they practice the well-known gull trick of dropping shellfish from the air
in order to break them. Sealing and whaling operations supply them with a
wealth of provender, but aside from such artificial food resources I believe that
1030 OCEANIC BIRDS OF SOUTH AMERICA
penguin eggs and chicks, whale-birds, and diving petrels make up the bulk of
their food during the nesting period. While they force larger sorts of birds to
disgorge more or less at this season, I presume that this freebooting method is
of greater importance to the skuas during their pelagic migrations than it is at
the breeding grounds. I have seen them attempt to carry off fledgling Kelp
Gulls, but always unsuccessfully, because of the pugnacity of the old birds in
detense. The South Georgian Terris likewise band together and are quite capable
of putting the skua to flight.
Hall credits the skua with being able to carry away a Kerguelen Teal. The
mate of my brig, the ‘Daisy,’ shot two South Georgian Teals, both of which
were seized by skuas before he could retrieve them. One was dropped and
subsequently recovered by the gunner, but the other was carried, dangling from
the skua’s bill, far up the hill of Albatross Island at the Bay of Isles. Out of
curiosity or hopefulness the skuas always follow a man who goes a-birding with
a gun, and under such circumstances he must be quick to save his game. I
believe that they soon learn to expect to be fed by human beings, which may
be why one skua used to follow me regularly as I rowed back and forth in my
dory between ship and shore at South Georgia. It would set its wings and glide
very slowly along, scarcely more than arm's reach above my head.
Of all the Brown Skua's bird victims, the worst sufferers are probably the
whale-birds (Pachyptila), which they seize as the latter come out of their
burrows. On one occasion an example which we had dug out fluttered away
a few paces before we could capture it, whereupon it was immediately seized
and carried off by one of a group of skuas which had gathered to watch the
digging. When, however, the whale-birds once get a good start, their highly
erratic flight enables them to escape. I have described such an incident in the
life history of Pachyptila desolata. The neighborhood of a skua nest containing
a chick that has been for some time out of the egg is sure to be littered with the
bones and feathers of whale-birds.
I have never seen the skuas bear food in their bills to the nesting site; it
appears that they always swallow it first and later disgorge in the presence of
a chick. Szielasko (1907, 597) believed, however, that at South Georgia the
skuas made deposits of food supplies in such hiding places as an unused burrow
of a petrel. At any rate, he once found a dozen dead whale-birds in such a hole,
and he concluded that they had been cached by a skua. I have no observations
bearing upon this suggestion. Buller (1888, 63) gives an excellent description
of how a captive skua from the New Zealand region would hold down its prey
with its sharp-clawed feet, pluck off some of the feathers, and devour the flesh.
The bodies of small birds would be bolted entire, but species the size of Pachyp-
tila would usually be more or less plucked, as well as disjointed, before being
engulfed. In some cases, however, the carcass of even a large petrel might be
swallowed whole, so that the tips of its wings would protrude from the skua’s
mouth for some time during the digestive disintegration of the first end to go
down. The long bones would be subsequently regurgitated.
At South Georgia one is always impressed by the fact that during days of
BROWN SKUA 1031
high winds, when sea birds gather in great numbers in the fords, the skuas pay
no attention to the whale-birds among which they mingle. It seems as though
they must have become conditioned by experience to the futility of pursuing
the agile petrels in the free and windy air. Perhaps for the same reason the
skuas ignore also the little Mother Carey's chickens, such as Wilson's Petrel.
I have frequently seen the latter species dancing on the water astern of my
anchored brig, and passing within easy bill's reach of skuas swimming or
fluttering in their search for scraps of blubber. But even more inexplicable is
the skua's attitude toward the tiny South Georgian Pipit (Anthus antarcticus).
Time and again I have seen examples of the latter practically run across the
webbed feet of their big, bloodthirsty, and generally untrustworthy neighbors.
Whatever the reason, the pipits apparently enjoy total immunity; it 1s quite as
though an ogre indulged himself in a single chivalrous whim.
Elsewhere I have spoken of the speed of the skua in flight, a fact impressed
upon me while watching the bulky birds overhaul and keep pace with Kelp
Gulls and various large petrels, harrying and worrying the victim in an attempt
to gain a secondhand dinner. They are always ready to make themselves annoy-
ing and impudent toward any species, however large—Hall (1902, 8) states
that even the Black-browed Albatross will settle in the ocean in order to escape
the molestations of the skua—and they will steal the eggs not only of the
grounded and therefore helpless penguins, but even those of Wandering Alba-
trosses and Giant Fulmars.
The skuas were always at hand when the crew of the brig ‘Daisy’ slew a
sea-elephant. The sailors, of course, credited them with having a keenly
developed sense of smell, a supposition favored likewise by many naturalists,
including Gain, who has written an account of the South Polar Skua’s uncanny
ability to find its way to a scene of blood-spilling. During the skinning of seals,
skuas will sometimes actually alight on a warm carcass at which men are at
work; even after being repeatedly driven away, they continue to stand about
in a ring only a few steps in diameter.
When mixed flocks of birds were feeding astern of my anchored vessel, the
superior alertness of the skuas over all other species would become at once
apparent. They always succeeded in getting the lion’s share of food tossed
overboard, and would snatch pieces of seal blubber or entrails practically out
of the bills of mollymauks and Giant Fulmars. If a piece of food was dropped
in the air by a skua or any other bird, it was invariably recovered by a skua
before it had struck the water. Once a skua alighted on the mincing table on
the deck of the ‘Daisy,’ where members of the crew were engaged in cutting up
sea-elephant blubber. The bird fed from the edge of the knife, so to speak, and
allowed itself to be touched.
One day when I had killed several King Penguins and was preparing to skin
out their heavy bodies before carrying the skins across a wide moraine toward
my boat, a score of skuas gathered about me within a few moments, and crowded
forward for the leavings. Several took bits of flesh and fat from my hand.
Pebbles tossed toward them caused them merely to watch, without any appre-
1032 OCEANIC BIRDS OF SOUTH AMERICA
ciation of the fact that my gesture might have been menacing. I discharged a
shotgun, with its muzzle held just over their heads, whereupon several of them
merely leaped off the ground, and all ceased their clucking chatter for a few
seconds. On this occasion I learned how useful I could make the skuas in
cleaning the fat from the inside of penguin skins. When the latter, turned inside
out, were placed before them, the skuas would pick off the blubber as cleanly
as it could have been done with a scraper, and in much less time. They would
snip off small bits with the hooks of their beaks, swallowing one after another
about as rapidly as a chicken picks up strewn corn. On one occasion I had 35
skuas ready to work, each attempting to perform on my behalf this fundamental
and arduous taxidermic process! My helpers battled unendingly, however, even
when there was ample room for all, and one or sometimes two old champions
monopolized each penguin skin most of the time, to the detriment of efficiency.
In fighting, they raised their white-marked wings, and jumped at each other
like game cocks, except that they did not use their claws. They knocked each
other down in jolly fashion, and pulled out feathers, the battles being half on
the ground and half in air. The victor always raised its wings and screamed
before turning again toward the banquet and driving off the birds which had
slipped into its place. Sometimes three or four of them would grasp one scrap
of meat, and pull until it was torn asunder. They would lean back vigorously
during such a tug-of-war, bracing their feet far forward and tilting their tails
quite to the ground. If one bird flew away with a billful in order to devour it
elsewhere, the others would doubtless suspect that he had a superior morsel,
for immediately the whole pack would leave its plenteous repast and follow
the fugitive, who was sure to be robbed unless he could gulp down his morsel
in the air. Their general principle seemed to be that “‘the far off hills are
greener.”
Skuas can swallow enormous chunks of food, their throats bul ging out bigger
than the head during the process. Several of them at South Georgia took in
without difficulty the eye-balls of King Penguins, spheres having the circum-
ference of a half-dollar. To one skua I offered the egg of a Shoemaker. It
promptly took it from my fingers, and swallowed it, shell and all. The average
measurements of a score of eggs of this petrel exceed 83 x 54 millimeters. Loran-
chet (1916, 306) reports that he once saw a skua at Kerguelen bolt the head of a
rabbit. This introduced mammal has become a regular part of their food at
that island, and skuas have even been seen to attempt to filch a rabbit out of
a dog’s mouth.
I have written enough to show that the skuas are the berserkers among birds.
They seem to have a diabolical gift to be a scourge. One day at South Georgia
a group of them pulled open the knot of a fish-trap I had left on the beach, and
dragged out and scattered the bones of a sea-leopard which the industrious
copepods had been cleaning for the benefit of science. The incomprehensible
part of this annoyance was that the trap lay beside the stripped carcass of a
freshly killed sea-elephant upon which a thousand skuas might have feasted to
repletion. But in spite of their voracity, rapine, and cannibalism, the skuas
BROWN SKUA 1033
quickly make themselves the beneficiaries of a peculiar, sentimental, anthropo-
morphic interest. When they crowd around you, and look up with bright,
fearless, unsuspicious, brown eyes, accept the bounty you offer them, and show
no more concern over the loudest shouts, whistles, or handclaps than if they
were stone-deaf, you succumb to their charm, and subscribe to the principle
that their supremacy of might must be deserved.
TRISTAN SKUA
Catharacta skua, subspecies
The skua of Tristan da Cunha and Gough Island, locally known as Sea Hen
or by the inelegant name of ‘‘Dirt Bird,’’ has by recent authorities been classified
with the Falkland Skua under the subspecific name antarctica.
Measurements of 8 specimens published by Hamilton, when compared with
those of 40 specimens of Falkland birds, show that, despite overlapping, the
Tristan Skua is a larger torm, particularly in the size of the bill and the length
of the tarsus. The size-range, as shown graphically in Hamilton's diagram on
page 170 of his paper, tends to link the Tristan race more closely with birds of
the antarctic islands than with those of the Falklands. I have seen no specimens
of the skua from either Tristan or Gough, but the measurements of the two
birds collected by Beck at Mar del Plata in October, and listed in line 9 of my
table, are of a size agreeing closely with the published dimensions of Tristan
and Gough specimens, and it is not unlikely that they had migrated to the
Argentine coast from one of these mid-Atlantic islands. The fact that the Mar
del Plata examples do not fit well into any of our other series of skuas is an
indication of how little we yet know, and of how cautious any ornithologist
must be in accepting the published records and determinations of southern-
hemisphere skuas.
When Wilkins (1923, 509) visited Gough Island in the Quest,’ between
May 28 and June 1, 1922, he found skuas not particularly numerous, but saw a
total of about twenty. Only a week earlier, however, he had observed them in
great numbers about each island of the Tristan da Cunha group, and had col-
lected three adults at Nightingale. The supposition is that the autumn exodus
of skuas from Gough Island had begun before the time of Wilkins’s arrival.
Captain Comer, as reported by Verrill (1895, 450), found very large numbers
of skuas at Gough Island, and killed about 300 of them for the sake of their
feathers. Comer states that the Sea Hens begin laying there after the middle of
September, and that they will replace their eggs if the nests are robbed. The
Rockhopper Penguins of this island also begin to produce eggs about September
15, and it is coincidentally with this that the skuas move in from sea in force
and begin to get their living by robbing penguin nests. They also kill young
albatrosses, and all the smaller birds that they are capable of catching.
At Tristan da Cunha, according to Mrs. Barrow (1910, 275), the skuas are
present all the year, and lay their first eggs during the month of August. Camp-
bell (1877, 65) observed them perching on the branches of low trees at Inacces-
1034 OCEANIC BIRDS OF SOUTH AMERICA
sible Island at the date of the visit of the ‘Challenger’ in mid-October. At this
time a very few nests still contained eggs. During the same visit, Moseley
(1879, 123) watched 30 or 40 skuas quarreling over the skinned bodies of
penguins on the beach of Inaccessible. He states that, in addition to rifling
the penguin colonies of eggs and chicks, the skuas feed even more upon the
various ‘‘night birds,’’ especially the Broad-billed Prions, which are pounced
upon as they issue from their burrows. The ground was strewn with the skele-
tons and long feathers of whale-birds, the meat of which had been eaten.
Three eggs from Gough Island measure 66.6 x 50.3, 73.7 x 51.8, 73.6 x 50.8
millimeters. Ten from the Tristan da Cunha group average 70 x 51 millimeters
(Mathews, 1932, 45).
This seems an appropriate place to quote the interesting, if somewhat indis-
criminate, notes of Captain C. C. Dixon (1933, 134) on skuas observed during
his long experience in the southern oceans.
The skua does not as a rule follow the vessel—a few circle around at various distances, a zig-
zag or two along the wake where some birds may be picking up food, is the extent of its attention
to the ship’s presence. If it happens to see a bird picking up food, the skua generally makes a
swoop at it so that it may drop it for his benefit. Then he is away on his wandering over the
waters. Even if it is a parasite it does not lack courage for it will attack the smaller albatrosses
in the air and force them to alight or disgorge . . .
Of all the ocean birds that I have had to do with the skua has the greatest hold on life. It has
the cat’s nine lives and a few extra for good measure. Whenever we desired to keep one of the
various birds we caught for either scientific or commercial purposes, a sharp blow on the head
usually finished it instantly. Not so the skua. One calm day we were out in a boat trying to cap-
ture a white-headed petrel, when a wandering skua was tempted by the bait. As I had never had
one to dissect, I thought we might capture this one. It was easily hooked and drawn into the
boat, given a sharp rap on the head that we thought was sufficient to kill it, but this only annoyed
it, so it was given a regular knockout blow as we certainly had no desire to see it suffer. It fell
into the bottom of the boat apparently dead, but soon revived. Then the second mate, who was
pulling stroke oar, grabbed it and gave it a blow sufficient to kill a good healthy ox and wrung
its neck. Now it did seem finished, and we devoted our energies to the capture of the white-
headed petrel aforesaid. A few moments later the second mate gave a yelp,—the skua had given
him a nasty jab in the leg and was scrambling over the gunwale of the boat. We did not try to
detain it, for it surely had earned its freedom .. . .
More than half the year’s birds are seen in summer. Then there is a continuous diminution
to the six per cent. that are met with in spring.
On seven occasions in eighteen years I have seen four at once. It is frequently seen in pairs,
but solitary individuals are more often seen than any other number.
THE JAEGERS, GENUS STERCORARIUS
The jaegers are small-sized relatives of the skuas, and all three species of the
former are birds of circumpolar, arctic, and sub-arctic breeding range which
enter the South American region as winter migrants. Along both coasts of
the continent, jaegers harry the smaller fishing species of sea birds and force
them to disgorge. They are therefore called by some of the same names applied
to the skuas, such as ‘‘Halcén de Mar’’ (sea hawk), ‘Pajaro Ladrén (thief-
bird), and ‘‘Gaivota Rapineira’’ (robber gull).
The Pomarine Jaeger, largest of the three species, is the rarest in South
THEVJAEGERS 1035
American waters, perhaps only because it winters chiefly in the open ocean at
a great distance from land. It was not collected during the Brewster-Sanford
Expedition nor during my own South American work, but Mr. Beck, who is
eminently qualified to identify the species in the field, observed an example off
Ancén, Peru, on May 8, 1913. A number of others have been collected in the
neighborhood of the Galapagos Islands, in Callao Bay, and in the eastern South
Atlantic, during the winter months of the northern hemisphere.
The two lesser species of jaegers are, on the other hand, regular winter visitors
to both coasts of South America. The Parasitic Jaeger seems to be the com-
moner of the two close alongshore. Mr. Beck, indeed, suggests in his notes
that the Long-tailed Jaeger may carry out the greater part of its migration
either far at sea or over the continents.
The Pomarine Jaeger is completely distinctive, at least as regards specimens
in the hand. The two other species are easily confused, especially when ages
and plumages are as miscellaneous as they are likely to be in the winter ranges
of the southern oceans. Between the Parasitic and the Long-tailed there is a
well-marked though slightly overlapping difference in the length of the tarsus
which makes a useful means of discrimination between them. This measure-
ment for the whole series of Brewster-Sanford specimens is as follows, a notable
point being that females of each species average slightly larger than males:
Minimum Maximum Average
RVFEILOFALIUS, PATGSSEUUS UBC ss oe ee eee aS 43 47.6 45.1 mm.
5 Orr BES es Ge gar elton, ee Le 45.1 48 46.6
Stercorarius longicaudus 4%. 2 1 ee 41.1 43.7 41.9
1 Re OO acct ame ere een 40.2 46.2 43.1
The bill character by which parasiticus and longicaudus are said to be dis-
tinguishable proves in some instances indecisive. However, all three species of
jaegers, in practically any plumage after the loss of the down, can be reliably
identified by the following excellent key compiled by Wetmore (1926, 129).
a'. Bill higher than wide at base; wing usually more than 350 mm.; in adult the middle pair of
Recenicessprodu throughout cwistedi on 0) oc eng he a nee pomarinus.
a’. Bill not higher than wide at base, wing less than 345 mm.; in adult the middle pair of rectrices
straight.
b'. Length of horny cere (supranasal saddle) decidedly greater than length of dertrum; tarsi and
feet black; three or more outermost primaries with shafts ivory yellow . . . . parasiticus.
b?. Length of horny cere (supranasal saddle) not greater than length of dertrum; tarsi wholly or in
part light in color, feet black; only two outermost primaries with shafts ivory yellow (the
shaft of the third sometimes light, but with a brownish tinge). ..... . longicaudus.
POMARINE JAEGER
Stercorarius pomarinus
Lestris pomarinus Temminck, 1815, Man. d'Orn., p. 514 (arctic regions of Europe).
Names: Synonyms of the specific name include pomatorhinus, fuscus, and sphaeriuros.
Adults, light-colored phase (sexes alike): Pileum, lores, and malar region, together with upper
parts, except nape and hind neck, plain dark sooty gray; anal region and under tail coverts lighter
1036 OCEANIC BIRDS OF SOUTH AMERICA
brownish gray, sometimes intermixed with whitish; rest of head and neck, including hind neck,
together with under parts of body, immaculate white, the auricular region and sides of nape more
or less strongly tinged with straw-yellow; bill dull brownish (whitish in life), its terminal third
(approximately) black; iris dark brown; legs and feet blackish, the upper portion of tarsus pale
bluish Cin life).
Adults, intermediate phase (sexes alike) : Similar to the light-colored phase but chest and hind neck
barred or transversely spotted with dusky, and lateral under parts irregularly barred with the same.
Adults, dusky phase (sexes alike): Entirely plain dark sooty grayish brown, with a slaty
cast in certain lights, the auricular region sometimes (usually ?) tinged with yellowish.
10 males: wing, 349-374 (361.9); tail, 172-243 (207.9); exposed culmen, 38-43.5 (40.4);
tarsus, 48-54 (52); middle toe [without claw], 42-47 (44.6) mm.
9 females: wing, 351-370 (359.7); tail, 128-205.5 (181.2); exposed culmen, 38-44 (40.2);
tarsus, 50-55 (52.1); middle toe [without claw], 42-48 (46.1) mm.
Young, light-colored phase: Head, neck, and under parts dull buff, everywhere barred with
dusky, the bars broad and sharply defined on under tail coverts and flanks, indistinct on head and
neck; upper parts dusky grayish brown, the scapulars and interscapulars tipped with buff, the
rump and upper tail coverts spotted with the same.
Young, dusky phase: Entirely sooty grayish brown, the breast, abdomen, and sides narrowly
and rather indistinctly, the under and upper tail coverts broadly and sharply barred with buff
(Ridgway, 1919, 681).
Distribution: Breeds throughout a circumpolar range along the arctic coasts of North America
and Eurasia, and also in Iceland. Winters in the southern oceans, southward to West Africa,
rarely to the Indian Ocean and Australia, and in America from Virginia and the Gulf of Mexico
southward to the Galapagos Islands and the coast of Peru.
The Pomarine Jaeger was observed once by Beck, off Ancén, Peru, asnotedabove.
Wynne-Edwards (1935, 298) reports that the autumn migration of this
species in the North Atlantic begins first on the American side, and is about a
fortnight later than that of the other two jaegers, perhaps because of its more
northerly and hence Jater breeding custom. By November or earlier the van-
guard of migrant Pomarines crosses the equator. The principal wintering
grounds seem to be in the eastern tropical and South Atlantic, where the hydro-
graphic conditions produce vast areas of relatively cool and rich surface waters.
It has been observed that ‘‘where . . . jaegers are the commonest sea birds,
they must depend largely on their own enterprise for food, rather than on
stealing from other species."’ Wynne-Edwards continues:
There is thus beyond doubt an important wintering-ground of the Pomatorhine Jaeger in the
waters off the West African coast, having its focus a little south of Cape Verde, in 10° or 12°N.,
17° W. Jaegers are numerous in winter from 8° to 25° N. off this coast. . . . To the south, for
all we know, they may regularly be present off Angola and southwest Africa, but records for that
area are very scarce. To the west they thin out rapidly.
Wynne-Edwards likewise draws a parallel to Meinertzhagen’s conclusions
regarding the phalaropes, and infers that Atlantic-American Pomarine Jaegers
may cross the Isthmus of Panama on migration, in order to winter in the off-
shore waters of the Humboldt Current. While no direct connection between
this species and phalaropes is suggested, it is of interest to note that Pomarine
Jaegers have been seen to pursue, capture, and eat phalaropes (Tuttle, 1911, 482).
While there are a number of published records for the Pomarine Jaeger in the
Gulf of Mexico, British Guiana, and the central South Atlantic, the South
American status of the species must still be regarded as uncertain.
PARASITIC JAEGER 1037
PARASITIC JAEGER
Stercorarius parasiticus
Larus parasiticus Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 136 (coast of Sweden).
Names: Synonyms of the specific name include crepidatus, richardsonii, and spinicaudus.
Adults, light-colored phase (sexes alike): Pileum and loral region grayish brown; rest of head,
together with neck and under parts except under tail coverts, immaculate white, the head more or
less strongly tinged with straw-yellow; upper parts uniform brownish gray, becoming darker or
dusky on primaries and tail; anal region and under tail coverts uniform brownish gray; bill light
horn-color, the terminal portion dusky or blackish; iris brown; legs and feet black.
Adults, dusky phase (sexes alike): Entirely plain dark sooty grayish brown, the neck more or
less tinged with straw-yellow.
16 males: wing, 301-340 (320); tail, 164.5-235 (188.9); exposed culmen, 28-35 (31.2); tarsus,
39.5-45.5 (41.9); middle toe [without claw], 33-37 (34.8) mm.
14 females: wing, 317-341 (323.7); tail, 176-226 (199.7); exposed culmen, 29-34.5 (31.8);
tarsus, 39-45 (42.1); middle toe [without claw], 32-38 (35.9) mm.
Young, light-colored phase: Head and neck streaked with dusky brown and cinnamon or
cinnamon-buff, the latter usually predominating; under parts more or less distinctly barred or
transversely spotted with the same; upper parts dusky grayish brown, the feathers tipped or
terminally margined with cinnamon or cinnamon-buff.
Young, dusky phase: General color dusky grayish brown or brownish gray, the wings and
tail darker; middle of neck, all round, indistinctly streaked with grayish white; under parts,
except chest and upper breast, barred with grayish white, the bars broad and distinct on under
tail coverts; scapulars, interscapulars, wing coverts, upper tail coverts, and feathers of rump
narrowly tipped or terminally margined with pale dull buff (Ridgway, 1919, 687).
Distribution: Breeds throughout a holarctic range, from the British Isles and northern Labrador
northward to the northernmost land areas within the arctic circle. Winters southward to the
Cape of Good Hope, Australia, and New Zealand, along the Pacific coast of America from Cali-
fornia to central Chile, and on the Atlantic coast from Florida to Argentina.
The Parasitic Jaeger has been observed by either Beck or myself along the
coasts of Peru, Chile, Argentina, and Brazil during every month between Oc-
tober and March, and in June. Localities of interest are as follows:
Peru: Huacho, Cafiete, Pisco Bay, June; Camana, in pursuit of Franklin's
Gulls, January.
Chile: Valparaiso, November, December, February, March—very common
at times in the bay; Corral, November and March; Chiloé Island, June; Strait
of Magellan, in pursuit of South American Terns (Sterna bindinmna), March.
Argentina: Mar del Plata, October 9. “‘More abundant than ever before
seen; flocks of dozens sitting on the water like gulls seven miles off shore. I
counted fifty of this and the Long-tailed species in one scattering string’’ (Beck).
Wetmore (1926, 129) observed and collected examples of the Parasitic
Jaeger southward of Cape San Antonio on the eastern coast of the Province of
Buenos Aires, during November, 1920. At this time and place they were far
less numerous than the Long-tailed Jaegers.
In the Brewster-Sanford Collection are 8 males and 15 females of Stercorarius
parasiticus representing birds of many phases, including examples with white-
barred, dusky, and clear brown or sooty, ventral surfaces. One specimen 1s
rufescent on the throat and breast. All had black legs, which constitutes a
point of distinction between the Parasitic and Long-tailed species. No sign of
1038 OCEANIC BIRDS OF SOUTH AMERICA
sexual activity was indicated by the gonads of birds collected even as late in
the year as the middle of March.
In addition to the specimens from the South American coast, the Museum
contains a uniformly sooty-colored Parasitic Jaeger collected by myself in the
equatorial Atlantic to northeastward of St. Paul Rocks, on September 27, 1912.
South American records of the species are numerous and widespread, from the
West Indies and Surinam (Kappler, 1881, 166) southward to Patagonia. An
adult female ‘‘with healthy ovaries’ has even been taken as far south as Bar-
bados on July 10 (Feilden, 1888, 350).
Although jaegers are commonly stated not to molest petrels, Wynne-
Edwards once saw two birds of this species tackling a Greater Shearwater.
LONG-TAILED JAEGER
Stercorarius longicaudus
Stercorarius loneicaudus Vieillot, 1819, Nouv. Dict. Hist. Nat., 32, p. 157 (northern Europe).
Names: Whiptail. Synonyms of the specific names include Jongicaudatus, cepphus, buffoni, and
hardyi, besides which the species has been reported upon under various names of the Parasitic Jaeger.
Adults (sexes alike): Pileum, loral, and orbital regions, and upper part of nape plain sooty
black or dull slate-blackish; rest of head and neck, including hind neck and lower part of nape,
straw-yellow, paler on chin and throat; upper parts, except as described, plain deep brownish gray
(lighter on back, where still paler anteriorly), the remiges and rectrices darker, becoming nearly
black terminally; two outer primaries with shafts white or yellowish white; chest (sometimes
breast also, more rarely even upper part of abdomen) immaculate white, shading posteriorly into
grayish, the under tail coverts, anal region, flanks, and (usually) abdomen being neutral gray;
bill blackish terminally, the basal portion brownish or horn-color; iris dark brown; tarsi and basal
portion of toes and webs light bluish gray in life, drying light olive or yellowish, the remaining
portion of toes and their webs black (Ridgway, 1919, 694).
This Jaeger, like the two other species, also has a dark phase, but it is so rare as to be almost
unknown, and no specimens of it exist in collections (cf. Wynne-Edwards, 1935, 308).
16 males: wing, 295-327 (309.1); tail (middle rectrices), 263-350 (299); exposed culmen,
27-31.5 (28.6); tarsus, 38-44 (41.1); middle toe [without claw], 31-36.5 G2.7) mm.
6 females: wing, 305-317 (313.3); tail (middle rectrices), 238-350 (295); exposed culmen,
27.5-30 (28.8); tarsus, 40-42.5 (41.8); middle toe [without claw], 31-34.5 G2.5) mm.
Immature: Under parts and upper tail coverts barred with varying degrees of ash-brown;
very little yellow on the sides of the neck; otherwise similar to adults.
Young: Ash-brown above, the head darkest; the feathers of the mantle and tail coverts merely
tipped with buff, but without any rufous tint; under parts dull grayish white, barred with ash-
brown (Ridgway, 1919, 695). :
Distribution: Breeds on arctic coasts of North America and Eurasia southward to northern Lab-
rador. Winters southward to Gibraltar and Japan, and to the coasts of Peru, Chile, and Argentina.
The Long-tailed Jaegers of the Brewster-Sanford Expedition were mostly
observed or collected well out at sea, the exceptions to this being examples
shot in the bay of Valparaiso, during November and December, 1913. Others
were taken about 150 kilometers to westward of Ancon, Peru, on June 11, 1913;
on the voyage between Valparaiso and Juan Fernandez during early December
of the same year; and over the Atlantic within 20 to 30 kilometers of the coast
near Mar del Plata, Argentina, in October, 1914.
In Beck’s series of this species, as in that of Stercorarius parasiticus, females
LONG-TAILED JAEGER 1039
greatly outnumber males, there being 14 of the former to only four of the latter.
All of the examples are either white-breasted or barred. The darkest is a male,
taken off Mar del Plata, which retains a single long central rectrix. At least
one of the Valparaiso specimens, dated November 21, is a bird of the year,
just changing from a very ragged and faded condition to a darker plumage in
which each brown feather of the dorsal surface has a buffy white edging. On
the labels of the Brewster-Sanford birds, the bill and feet are recorded as black,
the tarsi as blue or grayish blue. All had small gonads except a female collected
off the Peruvian coast on June 11, in which the ovaries were distinctly enlarged.
If this bird was then on its way toward arctic Alaska, it had but a month for
completion of the migration, courtship and mating, and the production of eggs,
provided it was to keep up to schedule. The latest normal date for egg-laying
is about mid-July.
Wetmore (1926, 130) observed and collected many Long-tailed Jaegers along
the beach to southward of Cape San Antonio, eastern Buenos Aires, during
November, when they seemed still to be southbound. Within a few days he
saw upwards of 1200 examples. He writes:
The birds traveled alone or in little groups of three or four, some wary and others very tame.
They drifted along, frequently scaling for long distances or occasionally flapping their wings,
never more than 50 feet in the air, often only a few feet above the sand. At intervals one dropped
lightly to the beach near the water mark to pick up a few beetles that had drifted ashore after
the storm and then remained to rest for a few minutes. Others more energetic harried the Trudeau's
terns with agile wing strokes until they disgorged their prey of fish on the sand, when the jaeger
stooped easily to pick it up and then continued its flight. Their steady southward movement
without pause to circle about or return was most impressive.
Beck (1910, 62) has noted the extreme rarity of the Long-tailed Jaeger along
the California coast, even though the two other species are common every year
between August and October in the Point Pinos region. In his notebook, he
has hazarded the opinion that the Long-tailed Jaeger may carry out a good part
of its migration overland, a theory which has likewise been advanced by Bent
(1921, 27). The idea is doubtless worth investigation, partly because of the
many specimens of this jaeger that have been taken during migration at locali-
ties far from the sea, and also because the Long-tailed is at once the rarest of
jaegers along the North American coasts and the commonest in the southern
oceans. Wynne-Edwards (1935, 306), however, regards this species as by far
the most pelagic of the three, and has described an impressive spring migration
flight near the middle of the North Atlantic. He finds that such movements
reach a maximum toward the end of May and are over before mid-June. The
‘autumn passage starts in the last week of July, reaches its height in the second
half of August, and is practically over by mid-October.’" We now know that
by the last date many of the birds have reached the northern border of the Sub-
Antarctic Zone along the coasts of Argentina and Chile.
Wynne-Edwards gives the following pen-picture of this species:
On a bright day the Long-tailed Jaeger is a graceful sight, buoyed along on light wings with
its ten-inch ‘'marlinspike’’ fluttering aft like a pennon in the breeze, and the yellow-tinged collar
and white belly gleaming in the sunlight. Often in clear weather it sails at a great height, and
1040 OCEANIC BIRDS OF SOUTH AMERICA
occasionally soars in wide circles like a buzzard; at other times it will chase and scrap with its
companions or any bird at hand, swooping and swerving and turning on its back as if it had no
joints at all. I saw this bird more often in parties than the others, though here as elsewhere,
three, four and five were the favorite numbers. To some extent young and old travel together,
though it was common in autumn to see groups of adults or of juveniles unmixed.
THE GULLS AND TERNS
FAMILY LARIDAE
The gulls and terns make up a well-defined group, divided into the respective
subfamilies Larinae and Sterninae. The relationship between the two branches
is close and clear, but no gull more than approximates the pointed, generally
slender bill which is characteristic of terns. The Laridae as a whole are usually
regarded as a “‘modern’’ product of the Charadriiform stock, at least by con-
trast with the auks, though fossil remains ascribed to the genus Larus are known
from as far back as Upper Oligocene strata.
In temperate parts of the northern hemisphere, exclusive of the Pacific basin,
the gulls fall into two well-marked divisions, namely, the hooded species and
those without a hood. In both groups the immature birds have a dark tail
band. Each group has also several representatives in the southern hemisphere,
but only in the Pacific and in southern South America do we find species that
agree with the northern forms in having a tail band when immature but differ
markedly in other respects. Most of these are birds of relatively heavy build,
with a tendency toward sooty coloration. Their principal characteristic, how-
ever, is the presence of a more or less defined hood in immature plumage, which
is generally lost in the adult stage. Lemwcophaeus scoresbii, for example, loses its
hood along with the disappearance of the tail-bar. Its range lies chiefly within
the influence of the Cape Horn Current. Larus belcheri has a hood only in youth,
but retains the barred tail in maturity. Its range is confined to the Humboldt
Current region. According to Saunders, its closest relative is Larus crassirostris
of the Pacific coast of Asia. Dwight, however, holds that belcheri has deeper,
even if less obvious, affinities with several of its American neighbors.
Larus fuliginosus, of the Galapagos, which has a hood at all ages and loses
the markings on the rectrices with maturity, may be close to the ancestral type
of all the Pacific forms. L. heermanni, of the California coast, has a hood in the
youthful stage and a black, white-tipped tail. L. modestus, of the west coast of
South America, resembles it in the hood of immaturity and the general colora-
tion, but differs in a tendency to lose the tail markings with advance in age.
Between South America and Australasia no gulls occur, although terns are
plentiful. Even L. dominicanus is absent from the South Pacific islands. But in
the Australasian region is found the large dark-mantled Gabianus pacificus, the
huge blunt bill of which somewhat resembles that of Leucophaeus scoresbii, al-
though the similarity, as pointed out below, may be no more than a specious one.
As Saunders (1879, 390; 1882, 520) has remarked, it is noteworthy that birds
possessing such powers of flight as certain gulls and their allies should remain
THE GULLS AND TERNS 1041
within highly confined distributional limits when the more apparent influences
which might formerly have proved a barrier to their extension have disappeared
for ages. It would seem as though the connection between the coastal gulls of
the northern and southern hemispheres is much closer in the Pacific than in the
Atlantic. The cool eastern Pacific currents, flowing equatorwards, are no doubt
in large measure responsible for this. A greater contrast could hardly be imag-
ined than that between the gulls, terns, and many other elements of the bird
life of the central Humboldt Current region in Peru and the avifauna of the
Brazilian coast between Pernambuco and Bahia, along which a warm ocean
current flows poleward.
In Larus cirrocephalus, a gull with a pale gray head which inhabits both
southeastern South America and the opposite African coast of the Atlantic, we
have the only hooded gull of the southern hemisphere with a range extending
outside South America. Another South American hooded gull, Larus maculipen-
nis, appears to be a representative of the palaearctic species, Larus ridibundus.
Among gulls, as among shore birds, it is quite possible that South America is
par excellence the last stronghold of certain “‘living fossils'’ which during long
ages have been pushed out from the northern land areas toward the periphery
of the world.
As Dwight (1925, 65) states by way of caution, however, one can hardly
more than guess as to which of the gulls are of primitive type. The species that
are darkest in the color of plumage, bill, feet, and eye would seem perhaps to
have the best claim to be so regarded, because they resemble in their pigmenta-
tion and lack of pronounced pattern the young of many species which later
develop highly specialized hues and patterns. The wings and tail of some species
remain very much the same in both young birds and old, and from such ‘‘struc-
turally ancestral’’ types the others have possibly been derived. The forty or
more species of gulls are, nevertheless, in the main so homogeneous that they
lend themselves to meaningful subdivision only with difficulty. It has proved
quite possible, for example, to erect a multiplicity of monotypic genera, a pro-
cedure which tends to nullify the value of genera as taxonomic units. In this
book I follow the arrangement of Peters (1934, 312), which is in most respects
a further simplification of the masterly study of Dwight. The latter author, in
reviewing the gulls of the world, has made use of the entire Brewster-Sanford
series and has examined as well nearly all other specimens that have come under
my own eye. I have therefore made free use of his excellent descriptions, and
have quoted the greater part of his measurements applying to South American
forms.
Pelagic gulls, such as are represented by the northern kittiwakes, are almost
wanting in South America, most members of the subfamily within our field
being continental or littoral. Even the Kelp Gull is for the most part an inshore
bird, but the Swallow-tailed Gull (Creagrus), of the Galapagos Islands, makes
long migrations on the high sea. It also forages well offshore during its daily
feeding régime at the nesting ground, and it may be called as nearly pelagic as
are most boobies.
1042 OCEANIC BIRDS OF SOUTH AMERICA
Gulls, like albatrosses and certain other sea birds, are master fliers, and,
since they lend themselves to familiar observation, their aérial technique has
been made the basis of many studies. Miller (1923, 5) has found that in ordinary
flight a gull of medium size will average about 120 strokes per minute. In the
rapidity of the wing-beat lies the secret of flight not only of gulls but of birds
in general. On the downward stroke a momentary vacuum is left above the
wing; in other words, the air pressure is removed above but maintained be-
neath, so that the bird is supported theoretically by a force exceeding one
kilogram per square centimeter of surface. The displaced air cannot rush in so
quickly in the wake of a large wing as in that of a small one. This explains
why a gull can support itself with only 2 strokes per second while a sparrow,
with a much greater wing-expanse in proportion to weight, must make 13
strokes per second.
It is a common sight to observe a gull travel long distances at a speed of from
20 to 35 kilometers per hour without a single flap of the wings. It is probable
that higher speeds would be recorded if faster steamers were to serve as a basis
of comparison.
Miller concludes, (1) that gulls take advantage of currents deflected upwards
from buildings, steamers, hillsides, etc. to indulge in soaring flight; (2) that
they do not engage in prolonged soaring in the absence of such currents; (3)
that the most favorable conditions for soaring about a steamer coincide with a
moderately brisk wind from the bow or from either beam; (4) that the “‘soar-
able’’ position varies with the direction and speed of the wind and the nature
of the object causing the updraught. With increasing briskness of wind about
a vessel, the soarable area tends to move more and more to leeward; in a moder-
ate wind the gulls are capable of soaring above the windward side.
Taking up, now, the terns, we find that the South American representatives
of their subfamily can be relegated to several categories, the relative distinct-
ness or affinities of which are at least clearer than in the case of most species or
groups of gulls.
In the first place, there are three, namely, Trudeau's Tern, the Large-billed
Tern (Phaetusa), and the Inca Tern (Larosterna), which are stamped with a
remarkably high degree of endemism. Trudeau's Tern is the least notable of
these, for its affinities are generally with members of a group within the genus
Sterna which has a world-wide distribution, but the other two seem extraor-
dinarily remote from their nearest relatives. The Large-billed Tern is chiefly
riparian, while the Inca Tern is exclusively coastal and is confined to the Hum-
boldt Current region.
Secondly, there are a number of native forms either specifically identical
with, or more or less closely related to, widely distributed northern-hemisphere
terns. The Gull-billed Tern (Gelochelidon), and the following species of
Sterna, belong here: Airundinacea, vittata, superciliaris, lorata. The Cayenne Tern
(Thalasseus eurygnatha) should doubtless be included with these. The members
of this group are likewise chiefly coastal or riparian, but Sterna vittata inhabits
isolated pan-antarctic islands as far southward as the shores of the polar con-
LEE IGULLS AND, TERNS 1043
tinent. It is a species which has often been erroneously reported upon under
the name of Sterna hirundinacea, but the latter is, in reality, closely confined to
the South American continent.
The next aggregation would include winter migrants from North America,
one or two of which have at the same time extended their breeding ranges
southward as far as the northerly coasts of South America. In this list are the
Black Tern (Chlidonias); the Common, Arctic, Roseate, and Least Terns, of the
genus Sterna; the Royal, Elegant, and Cabot’s Terns, of the genus Thalasseus.
Several of these are highly pelagic during their migrations.
Finally, there are the pan-tropical oceanic terns, such as the Sooty, the
noddies (Anois), the fairy terns (Gygis), and the gray ternlets (Procelsterna),
the last belonging exclusively to the Pacific Ocean. All of these inhabit islands
lying in remote reaches of the sea, but certain of them are, nevertheless, rela-
tively sedentary and not given to long migrations away from their nesting
grounds. The Sooty Tern and the noddies are, however, pelagic during the non-
breeding season, but of the courses and extent of their wanderings practically
nothing is yet known.
The South American Tern (Sterna hirundinacea) has been mentioned above
as an endemic species related to terns of the northern hemisphere. It has the
most extensive range of any tern strictly associated with the continent (cf.
Fig. 23, p. 165), and its distribution is most illuminating when considered with
relation to the hydrographic environment. In the southern parts of its range,
as in Tierra del Fuego and the Falkland Islands, this species nests during the
austral springtime. In the Humboldt Current region of the central Peruvian
coast, however, it breeds in midwinter (June). The same trait is also charac-
teristic of certain petrels of the Humboldt Current which, like the tern, may
have reached such latitudes gradually from the sub-antarctic south. It is as
though such species, so far as their period of reproduction is concerned, had
carried their own optimum climate northward with them into the tropics.
DOLPHIN GULL
Leucophaeus scoresbii
Larus Scoresbit Traill, 1823, Mem. Wernerian Nat. Hist. Soc., 4 (1822) p. 514, pl. 6, fig. 1 (‘South Shet-
lands’’ = probably Falkland Islands).
Names: Magellan, Blue, Red-legged, or Scoresby’s, Gull; ‘‘Gaviotilla."’ Synonyms of the
specific name are haematorhynchus and neglectus.
Characters: A medium-sized gull, with a stout, blunt, red bil, red feet, pale gray head and
ventral surface, slaty, black mantle, white tail, white-tipped black wings, and a broad white wing
band. In winter plumage the head is dusky.
Adults in breeding plumage (sexes alike): Head, neck, and most of ventral surface pale pearly
gray, a little deeper on the back of the neck than elsewhere; chin, upper throat, and crissum nearly
white; eye-ring white; mantle slaty black, the scapulars and secondaries broadly tipped with white;
primaries black with white apical spots except on the outer two, the inner quills much more
broadly white-tipped; secondaries grayer, very broadly white-tipped, forming a wing band 25-
40 mm. in breadth; wing-lining deep gray; tail white, including the quill shafts. Iris grayish white,
the skin of the lids crimson; bill, with deep mandibular angle, a straight gonys, and abruptly
decurved maxilla, carmine or cherry-red; legs and feet vermilion.
1044 OCEANIC BIRDS OF SOUTH AMERICA
In winter plumage the head has a dusky gray hood, reaching only to the sides of the somewhat
speckled throat, and the eye-ring is only half white (posteriorly).
Following are measurements of specimens from Chiloé Island, the Fuegian region, Rio Gallegos
(Argentina), and the Falkland Islands.
18 males: wing, 316-339 (328.1); tail, 129-142 (135.9); exposed culmen, 35-42 (9.5); depth
of bill at base, 13-16 (15.1); depth of bill at angle, 15-17 (16.2); tarsus, 47-54 (50.8); middle toe
without claw, 40-45 (43.1) mm.
18 females: wing, 306-327 (319.2); tail, 126-136 (131.3); exposed culmen, 34-41 (7.2); depth
of bill at base, 12-16 (13.9); depth of bill at angle, 14-17 (15.1); tarsus, 45-55 (48.6); middle toe
without claw, 38-46 (41.1) mm. (Dwight, 1925, 134).
Younger examples have the dark slaty hood extending into the eye-crescent, the forehead,
lores, and sides of head whitish, more or less spotted or streaked, and dark shaft streaks on the tail.
The iris is brown; the bill basally flesh color, distally darker, with a blackish subterminal spot;
the legs and feet brownish. In first contour plumage the back and mantle are hair-brown, tinged
with sepia, the feathers being basally grayish white; upper tail coverts yellowish white; head,
neck, and sides of throat pale brown; ventral surface and sides still paler, and somewhat spotty or
streaky owing to white feather shafts and dark subterminal areas. The first five or six primaries
from the outermost are entirely dark, and the tail bears a broad black subterminal band, which is
heaviest on the central quills and gives out toward the laterals, the outermost occasionally being
immaculate.
In natal down the back is grayish, rather indistinctly mottled or lined with clove-brown; the
head is similar but more clearly spotted; the under parts grayish, darker on the throat and with
finer speckling caudad. The general aspect of the down is very dark.
Three eggs are said to constitute the normal set. The three sets in the Brewster-Sanford Collec-
tion consist, however, of but one each and are doubtless incomplete, since all were quite fresh.
These are variable in shape, one being short-ovate, another subpyriform, the third intermediate.
The ground color of two is grayish olive, and of the third slightly darker and browner. All are
rather evenly spotted and blotched with areas of brown pigment, which are dark and rich when at
the surface and, of course, paler within the texture of the shell. In one egg the pigment forms a
broken patch at the larger end, and in another an incomplete circle. The 3 examples measure
62.8 x 43.9, 61 x 45, and 56.2 x 44.5 mm.
Distribution: The Falkland Islands, Tierra del Fuego and its surrounding islets, the Atlantic
coast of South America northward to the Gulf of San Jorge, and the Pacific coast to Chiloé Island.
Two examples known from Mocha Island, Chile, November 25, 1932 (Bullock, MS). (Erroneously
recorded as a resident in the Antarctic Archipelago. )
According to the original describer, the beautiful Dolphin Gull is “‘said to
frequent the frozen regions of the southern ocean.’’ The type specimen was
brought to Europe by a sealing vessel that had visited the South Shetland
Islands but, judging from other natural-history objects in the same consign-
ment, the gull had in all likelihood been obtained em route at the Falklands.
At any rate, the species is no more than a casual straggler to the southerly
islands of the Scotia Arcgand the only antarctic record worthy of any credence
is based upon a specimen said to have been obtained at sea near the South
Shetlands (Saunders, 1901, 232). The species was not encountered by the French
Expedition in West Antarctica, nor is it listed by Bennett (1926, 319) among
the birds of Deception Island and adjacent regions. Therefore it cannot properly
be considered an antarctic gull, as Dwight (1925, 137) has called it.
Peters (1934, 313) places this gull in the genus Gabianus, thus linking it
with the large Australian species (G. pacificus) hitherto regarded as monotypic.
The sole point of pronounced resemblance between Gabianus and Leucophaeus,
DOLPHIN GULL 1045
however, would seem to be in the bill or, rather, in the lower mandible. In
discussing the highly variable shape of the bill of Larus dominicanus, 1 show
elsewhere (p. 1061) how an extraordinarily deep mandible occasionally crops out
among birds of this species, and I believe that to suggest a particularly close
relationship between Gabianus and Leucophaeus on that score alone is to go much
farther than the facts warrant. So far as we can judge, the affinities of the Dol-
phin Gull are rather with the “‘gray gulls,’’ such as Larus heermanni.
During the Brewster-Sanford Expedition, Beck observed the Dolphin Gull
at many localities from Chiloé Island southward to Cape Horn, thence north-
ward to the Falklands, and up the Atlantic coast of Patagonia. Excellent series
of specimens, representing birds of practically all ages and stages of plumage,
were taken at Ancid, in various parts of the Strait of Magellan and Beagle
Channel, at False Cape Horn, Hoste and Morton Islands, the Falkland Islands,
and Rio Gallegos. On December 17, 1914, Beck found these birds breeding on
a small inaccessible rock just off Hoste Island, and next day he located a similar
colony of about 30 nests on one of the little Ildefonso Islets, which lie well out
at sea to westward of the Horn. At both these places the Dolphin Gulls seemed
to cling very closely to their breeding stations, for during a week's stay at an
anchorage in Trefusis Bay, less than 7 kilometers from Hoste Island, Beck saw
not a sign of the birds.
A year later he found the Dolphin Gulls just beginning to nest at Sea Lion
Island, south of East Island of the Falklands, the very first eggs being laid here
on December 17. Judging from Beck's notes on the labels of female specimens,
mid-December appears to mark the beginning of egg-laying throughout both
the Falklands and the Magellanic region. Birds of the species apparently breed
while they are still young enough to have mottled brown heads. Most of the
Sea Lion Island nests, which were constructed of grass-stalks and other vegeta-
tion, were built in clumps of tussock around the borders of a lagoon much fre-
quented by penguins, ducks, and gulls, and a few were placed in insular hum-
mocks standing near the middle of this pond.
Vallentin (1924, 305) and Cobb (1910, 68; 1933, 20) state that the Dolphin
Gull is uniformly distributed throughout the Falkland Islands, and that it nests
usually in small colonies which are likely to be in juxtaposition with those of
other birds, such as the “‘Big Gulls’’ (Larus dominicanus). The former author
infers that the predilection of the Dolphin Gull for breeding close to such
untrustworthy neighbors as Kelp Gulls may offer the smaller species a certain
amount of protection from the skua. Nevertheless, the latter universal enemy
succeeds in destroying a large proportion of Dolphin Gull eggs or chicks.
Vallentin adds that Dolphin Gull nests are as a rule more elaborate than those
of most gulls, often forming good-sized heaps of grass and diddle-dee twigs.
The colonies are equally likely to be at the edge of high water, as described
above, or well inland among bogs or growths of scrub.
At low tide the Dolphin Gulls search the rock pools for food and assiduously
pick over the great piles of kelp washed ashore by storms. They are always
‘ready, however, to steal unguarded eggs from penguins and shags and, according
1046 OCEANIC BIRDS OF SOUTH AMERICA
to Cobb, will even plunder the buckets and wheelbarrows of human eggers in
the penguin colonies. Cobb has seen these birds treat the tough-shelled penguin
eggs as many gulls do mussels, to wit, carry their prospective meal a short dis-
tance above the ground and drop it to crack it open. The fragile cormorant
eggs are, of course, readily pierced by their stout bills. At Sea Lion Island Beck
found that the Dolphin Gulls quickly gathered around the incubating Giant
Fulmars, with the nauseating object of gobbling up the squids and carrion
which the big petrels disgorged at human invaders of their territory. He learned
at Kidney Island that the Dolphin Gulls make short work of the carcasses of
Rockhopper Penguins and other birds.
In winter, according to Cobb, the Dolphin Gulls become half domestic
around some of the outlying settlements in the Falklands. At this time of year
the omnivorous creatures gather to feed with the poultry and, unless they are
constantly shooed off, they succeed in getting much more than their fair share
of the food. From this observation, together with the fact that Beck collected
specimens at Ushuaia and near Cape Horn during midwinter and early autumn,
I judge that the species is sedentary throughout its range, northward movements
of individuals along the Atlantic coast being sporadic rather than seasonal.
Oustalet (1891, 179) has already recorded examples from Gable Island, Orange
Bay, and other Fuegian localities, during the months of July and August. Beck
observed young and old birds feeding with Kelp Gulls and oyster-catchers at
Magallanes, on July 4, 1914.
Hellmayr (1932, 413) is of the opinion that the Dolphin Gull occurs only as
a non-breeder in the vicinity of Chiloé Island, even though he refers to a male
collected there at the height of the nesting season. Beck's observations for
this locality are inconclusive, since they were made in April. He saw many
Dolphin Gulls off Ancid, however, both feeding in tidal streaks with the terns
and standing on small rocky islets occupied by sea-lions. The species has been
taken so often at Chiloé, and even as far up the coast as Mocha Island, that I
believe it breeds well northward through the little known archipelagoes of
southern Chile.
Cobb (1933, 20) states that this gull at times utters a peculiarly piercing
cry, which is notable in the Falklands for its capability of putting a horse into
a panic.
DUSKY GULL
Larus fuliginosus
Larus fuliginosus Gould, 1841, in Darwin, Zodl. Voy. ‘Beagle,’ 3, p. 141 (James Island, Galapagos
Archipelago).
Names: Galapagos Gull; Sooty Gull; Lava Gull. A synonym of the specific name is neptunis,
besides which this species has been reported upon under the specific names of several other species,
such as belcheri and heermanni.
Characters: Of uniformly dusky grayish or deep brown plumage, with dusky wings in both
young and adult stages.
Adults in breeding plumage (sexes alike): Head with a dark sooty brown or sometimes slightly
grayer hood, which extends to the chin and is clearly marked off from the gray of hind neck and
throat; eye-ring whitish gray; an obscure black eye-crescent; mantle deep mouse-gray, the rump
DUSKY, GULL 1047
paler; chin brown, in contrast with the gray throat; remainder of ventral surface paling on breast
and abdomen, the crissum becoming abruptly nearly white; primaries black, with yellowish white
shafts, the inner quills with gray inconspicuous apical spots; tail clear pale gray, except for the
middle rectrices which are as dark as the mantle, and the outer quills which are nearly white;
upper tail coverts pale gray, under coverts still paler. Iris lemon-yellow, the eyelids dark crimson;
bill dark bay, distally blackish, and with a burnt sienna tip to the maxilla; feet dark prune-purple
(blackish in dried skins), the plantar surface of the webs bay, and of the toes rufous.
In non-breeding plumage the eye-ring becomes obscure anteriorly, the color of the eyelid is
duller, and the bill turns nearly black except for a distal red area.
10 males: wing, 330-352 (345.4); tail, 140-151 (146.3); exposed culmen, 41-45 (43.5); tarsus,
53-58 (55.9); middle toe without claw, 41-45 (43.5) mm.
8 females: wing, 332-344 (337); tail, 132-141 (136.5); exposed culmen, 40-42 (41); tarsus,
52-55 (53.4); middle toe without claw, 39-42 (40.4) mm. (Dwight, 1925, 141).
These measurements substantially agree with those of 104 specimens recorded by Gifford
(1913, 45), who also gives the length in the flesh of 2 females as 445 and 450 mm., and their wing-
expanse as 1075 and 1095 mm. j
Younger birds have the back slaty, the rump and tail coverts grayer, the head dusky gray or
sooty brown, much darker than the tone of the back with which it blends. The ventral surface
is sooty brown, somewhat grayer on the throat, breast, and under,tail coverts. The tail shows a
very definite subterminal band, made up of dark, somewhat irregular blotches, which are slightly
if at all indicated on the outermost rectrices.
In juvenal plumage the prevailing tone is deep brown, the feathers with buffy edges. The iris
is brown, the bill wholly blackish. The natal down is apparently unknown.
The only known egg was taken from the oviduct of a bird shot at Albemarle Island on Novem-
ber 10, 1897. It is of pale greenish ground color, with liver-brown spots and patches, and under-
lying blotches of purplish mauve, and measures 61 x 43 mm. (Rothschild and Hartert, 1902, 413).
Distribution: Resident at the Galapagos Islands, nesting at some and wandering to others
after the breeding season.
The Dusky Gull, which appears to be entirely sedentary within the limits of
the Galapagos Archipelago, since it has never been captured elsewhere, is a
not-distant relative of Larus modestus of the Peruvian coast. Like the latter,
moreover, it is a bird of sandy shores rather than of the sea cliffs. Still another
point of resemblance. to the mainland species is the fact that, despite the great
amount of field work which has been carried out at the Galapagos Islands, the
nest of the Dusky Gull has not yet been found, and the only known egg ts one
taken from the oviduct of a bird shot at Albemarle Island on November 10,
1897 (Rothschild and Hartert, 1902, 413). This discovery might be taken as
indicating the time of the nesting season, were it not for the fact that specimens
collected by Beck during the expedition of the California Academy of Sciences
were found to have enlarged gonads during the months of May and July as well
as in October and November (Gifford, 1913, 43). Gifford reports that pairs of
the gulls would at times swoop at a human intruder as if attempting to frighten
him away from a nest which, however, could never be located.
The friendliness and lack of fear that the Dusky Gulls share with so many
other Galapagos animals have been commented upon by many visiting natural-
ists. These gulls were the constant companions of Beebe’s party at the islands.
They trotted up and down the beaches in train of human beings, and whenever
the seine was drawn their excitement became keen. They would fairly hop up
and down with eagerness when the fish began to leap over the net, and would
1048 OCEANIC BIRDS OF SOUTH AMERICA
afterwards gorge themselves until the tails of little fishes protruded from their
beaks. Ordinary apparatus they were content to watch in silence, but they
apparently learned to recognize at once the long poles of the seine, which they
greeted with outcries that were interpreted as rollicking peals of laughter
(Beebe, 1924, 64).
At Indefatigable Island, Habel found the Dusky Gulls so inordinately
friendly that they became a nuisance. They were forever devouring the meat
he had hung out to cure, invariably returning as soon as they had been driven
away. Of stones tossed toward them they took absolutely no notice unless
they were actually hit (Salvin, 1877, 505). Gifford contrasts their trusting
and ingenuous behavior with that of the migrant Franklin's Gulls, which come
to the Galapagos from a part of the world in which nearly all creatures recog-
nize man as at least a potential enemy. Tameness or wildness are, however,
largely reactions of season or locality or, more directly, of physiological
rhythm. The Franklin's Gulls are themselves absurdly tame in the plowed
fields of their summer range in North America; it is only during the winter
migration that they tend to become shy and easily frightened. In the same way,
the Galapagos Fork-tailed Gull (Creagrus furcatus) can almost be posed for
photography with the toe of one’s boot on its own lava ledges. When, how-
ever, it travels far at sea as, for example, down the Peruvian coast, it becomes
an extraordinarily shy bird which, nine times out of ten, takes flight from the
surface of the ocean long before a small boat can approach it within range of a
Camera or even of a gun.
The natural food of the Dusky Gull appears to consist largely of beach
crustaceans, but the birds are scavengers of the first order, quick to gather at
the slaughter of a bullock, seal, or tortoise, and equally ready to appear in half-
domesticated guise and to mingle with the chickens at such places as Villamil,
the Ecuadorian village on Albemarle Island. At the scene of a recent slaughter
in this locality, Gifford made the following observations regarding the habits
of the Dusky Gull:
Two or three adults were bullying the younger birds. Whenever an adult desired a piece of
meat on which one of the younger ones was pulling, he would lower his head, arch his neck, and
give a long cackling call, at the same time making a short rush at the enemy. The young birds
always got out of the way when such tactics were pursued. There was one immature bird imitating
the calls of the adults, its voice, however, being harsher. Both young and adults had a wholesome
respect for dogs and chickens. They would allow a man to approach within four or five feet of
them before flying or running (Gifford, 1913, 43).
The same author adds:
At Wreck Bay, Chatham Island, about three weeks later, I saw three adults chasing other
adults about and making the same long cackling calls, always standing very erect for a moment
before giving the call. In this case their actions may have been a form of courtship.
This species calls throughout the year, uttering a short squawk as well as the long cackling
call, which latter can best be described as beginning with a chuckle and then breaking into a
cackling laugh.
Not infrequently this species was seen in company with various other birds. Of such associa-
tion the three following instances are good examples: 1. One day in early March there were a good
DUSKY GULI 1049
many paddling about and calling in one of the lagoons near Villamil. Intermingled with them
were Egrets, Galapagos Herons, Bahama Pin-tails, and Black-necked Stilts. 2. At southeast
Narborough this species was noticed in company with Blue-footed Boobies, Flightless Cormorants,
Brown Pelicans, and Galapagos Herons, on a small islet about ten by thirty feet in dimensions.
3. Ona rocky point on the northeast side of James Island a gull was seen standing in the midst of
a compact flock of Blue-footed Boobies.
Their competitors on the water seemed to be chiefly the Graceful Petrel and the Man-o'-war
Bird. These two species were usually present whenever there was any refuse about. Other petrels
of [sic] the Dusky Shearwater also entered in a lesser degree into the competition. About the
settlements, chickens, dogs, cats, and pigs were their chief rivals.
The feet of individuals of this species seem to be subject to a good many accidents, for speci-
mens with split webs were frequent and those with deformed toes occasional.
GRAY GULL
Larus modestus
Larus modestus Tschudi, 1843, Wiegm. Arch. fiir. Naturg., 9, pt. 1, p. 389 (shores of the Pacific Ocean =
Lurin, South of Lima, Peru).
Names: Called in Peru ‘‘Mateo"’ and ‘‘Torero.’’ Synonyms of the specific name include bridgesé
and polios, besides which this gull has also appeared in the literature under the name fuliginosus, a
species in reality peculiar to the Galapagos Islands.
Characters: A gull with rather slender black bill, of uniform mouse-gray body color, black
wings, a banded gray tail, and a hood which is white in the breeding season but brown in winter.
Adults in breeding plumage (sexes alike): Hood completely white; mantle, rump, and tail
coverts dark neutral gray; wings dull black, without edging on the quills except that the proximal
3 or 4 primaries are faintly tipped with grayish white; secondaries rather broadly white-tipped,
forming a wing-bar; greater and outer coverts mouse-gray, the median and lesser coverts grayer;
primary coverts and alula brownish black; axillars and wing-lining grayish clove-brown; tail
clear gray, slightly and somewhat variably banded, the middle rectrices with dusky shaft streaks;
ventral surface, caudad from the white hood, uniformly gray like the mantle. Iris brown; bill
and feet black.
Adults in winter plumage have a wood-brown hood, somewhat paler and more pinkish than
in younger stages, an inconspicuous grayish eye-ring, and a faint dusky eye-crescent. Dwight
(1925, 146) states that although the plumage cycle normally requires three years, certain members
of this species become virtually adult in their second year.
5 males: wing, 314-337 (329.2); tail, 117-131 (124); exposed culmen, 40-43 (41.8); tarsus,
48-55 (53.2); middle toe without claw, 34-41 (38.2) mm.
14 females: wing, 299-328 (318.7); tail, 116-122 (119.6); exposed culmen, 37-41 (39.6); tarsus,
46-51 (48.7); middle toe without claw, 33-37 (34.6) mm. (Dwight, 1925, 144).
The average weight of three specimens collected at the North Chincha Island, October 27,
1919, was 366.6 grams.
In the first winter or non-nuptial plumage the mouse-gray feathers of the dorsal surface have
partly dusky centers, and the head is’without a hood, the hind neck being darker than the back,
the feathers basally grayish white. The ventral surface is largely mouse-brown, marked by dusky
clouding. Worn feathers often become exceedingly bleached or almost yellowish. The tail is
broadly and completely banded, the blackish area being as large on the external as on the central
quills, and more nearly terminal.
In the juvenal plumage the dorsal surface is prevailingly pale clove-brown, the feathers rather
broadly edged with grayish buff; the head and neck are similar but with very narrow feather mar-
gins, and there are broad pinkish buff edgings on the under tail coverts. The wings are brownish
black, the secondaries alone showing pale grayish tips. The coverts, tertials, and scapulars are
conspicuously buff-edged; wing-lining and axillars dark grayish clove-brown; tail brownish black
with very narrow buffy white tipping, which often extends to the outer webs of the outer rectrices.
1050 OCEANIC BIRDS OF SOUTH AMERICA
Natal down, nest, and eggs unknown.
Distribution: Breeding chiefly or exclusively on the mainland coast of Peru, and recorded
from Cautin, Chile, northward to Manta, Ecuador.
This demurely garbed little gull, which behaves like a sandpiper, is one of
the most familiar birds wherever rocky and beetling coasts give way to sandy
beaches in Peru and the northern half of Chile. Its commonest native name,
“Torero,’’ has reference to the agile manner in which it dodges back and forth
in front of breaking waves, with the movements of a bull-fighter facing his
furious antagonist. Another name, “‘Mateo,”’ is said to mean a “‘worrier,’’ and
to refer to the plaintive, mournful notes of this gull. I find, however, no lin-
guistic authority for the word.
The Gray Gull is related to the Dusky Gull of the Galapagos Islands, and to
Heermann’s Gull of the Pacific coasts of Mexico and California. It particularly
resembles the latter in that it has a dark hood when in winter plumage, which,
through a pre-nuptial moult in September and October, is replaced by a white
hood to be worn throughout the season of southern-hemisphere summer.
The Gray Gull has been collected by members of many American Museum
expeditions to the west coast of South America, and we have specimens or
satisfactory records from the following localities.
EcuaDor
Manta and Machalilla, February 9, 1920. Many feeding along sandy beaches
(Murphy).
Point Santa Elena, middle of February, 1925. Numbers seen and one col-
lected (Murphy and Heilner).
Jambeli Island, Gulf of Guayaquil, July 18, 1922 (Chapman).
Flats of the River Guayas, near Guayaquil. Noted on several occasions
between January 9 and March 7, 1925 (Murphy).
PERu
Point Parifias and neighboring parts of the coast, January, 1925. Several
specimens captured locally, or observed in an aviary at the police barracks in
Negritos (Murphy and Heilner).
North of Paita, March 5, 1925. One seen (Jaques).
Eten, January 4, 1913. Flock on the beach (Beck).
Salaverry, March 5, 1925. Present in great numbers (Jaques).
Ancén. Observed and collected by Beck during April and May, 1913, and
found at the same locality in groups of thousands by Murphy during December,
and by Jaques during February.
On sandy mainland and insular beaches about the harbor of Callao, and at
Chorrillos. A short distance to southward it was almost equally abundant
during various parts of the year.
Pisco Bay region. Common everywhere during Beck's field work in June
and July. Until about the middle of November, I also found these gulls at
islands, such as the Chinchas and Ballestas, wherever there were small sandy
GRAY GULL 1051
beaches, but at about this date they completely disappeared, probably to seek
breeding sites on the mainland shores.
Independencia Bay. Extremely abundant during mid-November, 1919
(Murphy).
Mollendo. Common, January 10, 1925 (Murphy); Paessler (1932, 42) also
records it from this port during June.
Ilo. A female taken August 23, 1925 (Fagan).
CHILE
Beck observed this gull at Iquique, Antofagasta, Valparaiso, Talcaguano
and Corral, between August and November, 1913, and collected numerous
examples near the last two localities during October and the following March.
The Museum collection also has specimens taken at Tofo, north of Coquimbo,
in July and February by Hallinan, and others from Puyehue, Cautin, collected
by Bullock in January and February.
In view of the predilection of this gull for sandy beaches, and its known
presence at many Peruvian islands, it is surprising that it has not been recorded
from Lobos de Tierra, which has the most extensive beaches of any island on the
west coast. I was there during January, which may have been the wrong
season, but Coker apparently did not find the species during his much longer
visit.
The records cited appear to cover the entire known range. So far as I can
learn, the nest and eggs of the Gray Gull have never been described and probably
never discovered. Specimens which I collected at the Chincha Islands about the
end of October, 1919, were clearly at the verge of their season of reproduction.
For many weeks the birds had been feeding regularly at the Chinchas and
neighboring islands, but as noted above, they all departed rather abruptly
about the middle of November. During my field work in Peru I combed over
with great care the surface of upwards of 30 islands and islets, and succeeded
in locating the nests of practically all the species believed to breed upon them
during the period between October and January. I am quite certain, not only
because of my failure to find the nests of the Gray Gull but more particularly
because of its absence from the islands throughout the spring and summer
seasons, that it retires to some part of the continental coast when the courtship
period is at hand. During December the birds were more abundant than ever
on the broad smooth beaches of Paracas Cove, at the head of the Bay of Pisco,
and along similar extensive strands lining the southern and eastern shores of
Independencia Bay. May it be possible that the Gray Gull, like certain petrels
of the Humboldt Current region, makes its nest on the high pampa at some
distance back from the ocean, or on the summits of the lofty, cloud-capped
promontories which loom hundreds of meters above the breaking waves?
Whatever its nesting habits, it is certain that this gull feeds exclusively
along sandy shores, where it mingles with sandpipers, plovers, migrant Hud-
sonian Curlews, and the resident, White-breasted Oyster-catchers, rather than
1052 OCEANIC BIRDS OF SOUTH AMERICA
with other members of its own genus. I never saw one alight upon an exclusively
rocky island. At the Chinchas, which are lined mostly with granite cliffs,
there are a few small gaps or coves with short sandy beaches at their heads.
In such spots as these the Gray Gulls gather, neglecting all other parts of the
islands. During October and early November, 1919, the landing place at central
Chincha Island, below the Guano Administration building in which I made
headquarters, was occupied every morning and sometimes at other periods of
the day by a ballet of the gulls, which were torever dancing back and forth in
front of the lapping waves. To escape the inrushing water they preferred to
run rather than to fly, and by the same means of progression they would pursue
the backwash to its lowest ebb, hastily picking about in the sand before they
had to retreat once again. Among this group of birds was a one-legged gull
which had to use its wings as balancers, and to fly back and forth, in the endless
rhythm which its fellows accomplished on foot. The crippled bird seemed,
nevertheless, to be as well fed and quite as full of joze de vivre as any of the others.
The special interest of the Gray Gulls in sandy rather than stony beaches was
explained by their stomach contents, for the great bulk of their food proved to
be made up of the sand-bug or hippa (Emerita analoga), a member of an almost
world-wide group of crustaceans which are confined entirely to sandy strands.
In Peru, this little creature is known as the ‘‘mui-mui'’ and it is used not only
as bait by fishermen but also as human food. In the northern part of the country,
particularly, it seems to be a staple article of diet among the local Indians. As
many as six of the mui-muis, which are rotund, heart-shaped creatures with
lengths up to 25 millimeters, or thereabouts, have been found in the stomach
and gullet of a Gray Gull. Other material identified included bones of fishes,
the hard jaws of Nereid worms, gravel, and a few feathers.
BELCHER’S GULL
Larus belcheri
Larus Belcheri Vigors, 1829, Zool. Journ., 4, p. 358 (no locality = Peru).
Names: The names ‘‘Simeén’’ and ‘‘Gaviota’’ seem to be the commonest designations of this
gull in Peru. It is also known as the South American Lesser Black-backed Gull. Synonyms of the
specific name include melanurus, frobeeni and, through misidentification, fuliginosus and scoresbit.
Characters: A gull with a heavily red- and black-tipped bill, subterminally banded white tail,
wholly black primaries, brownish black mantle, and white head.
Adults in breeding plumage (sexes alike): Head and ventral surface white, with a pale grayish
wash on the hind neck and breast; mantle deep brownish black; primaries black, the inner 3 or 4
grayer and with narrow white tips; secondaries and tertials slatier, with white tips 15-20 mm. in
breadth; wing coverts like the mantle; tail white, with a subterminal broad black band, succeeded
by white tipping 6-10 mm. in breadth. Iris brown; bill basally bright yellow, both mandibles
tipped with cherry-red, and with a superior, subterminal black spot on the maxilla; legs and feet
bright yellow.
In winter plumage the head is covered with a dull brownish black hood, extending well below
the eye which, however, is encircled by a white ring, dusky near the canthi. The flesh colors are
somewhat duller than during the breeding season.
6 males: wing, 348-372 (361); tail, 128-143 (135); exposed culmen, 50-52 (51.3); tarsus,
63-66 (64.1); middle toe without claw, 47-52 (49.3) mm.
BELCHER S$ GULL 1053
8 females: wing, 330-352 (340.6); tail, 124-143 (135.7); exposed culmen, 46-51 (47.8); tarsus,
55-60 (58.1); middle toe without claw, 43-47 (45) mm. (Dwight, 1925, 159).
The wing-spread of a male was 1235 mm. The average weight of a male and a female shot at
the Chincha Islands, October 24, 1919, was 670 grams.
In younger examples the mantle is brownish slate, the rump pale gray, becoming white on the
upper tail coverts; the head extensively slaty brown, with faint whitish edgings on the forehead;
the white ventral surface duskily flecked and almost solid dusky on the jugulum; the breast pale
gray, merging with the whiter abdomen and crissum. The color of the wings is browner than in
adults, the tipping of the inner primaries brownish, the tail dusky, often mottled with whitish.
In juvenal plumage the back and mantle are pale clove-brown, the feathers subterminally
darker and very broadly edged with pale buff, which fades toward whitish; head blackish clove-
brown, faintly edged with buff, the hind neck richly sepia in contrast with the back; forehead
paler because of wider pale edgings; no obvious hood, the occiput fusing with the brown nape and
this in turn with the back; eye-ring whitish, with dusky speckling; eye-crescent dusky; ventral
surface brown, the feathers of breast and sides whitish basally with deep brown subterminal bands
and buffy white edgings; the chin dull white, obscurely streaked and spotted; abdomen, flanks,
and crissum dull white; under tail coverts subterminally with sparse dusky barring or spotting;
primaries dull black, the inner quills with whitish or buffy edgings; secondaries, tertials, and
greater coyerts narrowly edged with whitish or brownish; wing-lining pale clove-brown, edged
with buff; alula and primary coverts dull black; tail dull black, with inconspicuous white or
‘fogged’ areas basally, increasing outwards and most marked on the distal rectrices, in which the
outer webs and three-quarters of the inner are mostly white, all the quills with narrow whitish
tips, the central pair dusky to base. Bill pale greenish yellow, more or less flesh-colored basally,
and with a subterminal black band on the greater part of the area which is cherry-red in the adult.
The tip of the maxilla is orange-red. The legs and feet are pale greenish or grayish yellow.
The natal down is extraordinarily pale. The dorsal surface is prevailingly grayish white,
sparsely lined or mottled with pale clove-brown; the head is whiter, with a few bold dark spots
arranged in irregular lines; the ventral surface is grayish white, very faintly buff, and practically
unmarked save for small black spots at the side of the chin, and an obscure dusky speckling caudad.
I collected the first known eggs in 1919. A set of three, slightly incubated, from San Pedro
Islet, Pescadores group, Peru, December 13, are ovate, somewhat attenuated and pointed at the
smaller end, one of the three slightly blunter and more abruptly rounded at the larger end than the
others. The ground color is deep olive buffy, the spotting very evenly distributed over the entire
shell and comprising irregular masses of pigment up to 8 or 9 mm. in diameter which, wherever it
lies at the surface, is of a blackish brown hue. Underlying spots appear grayer or lilaceous. In
one example most of the pigment is more or less buried, giving the whole egg a milky cast. The
dimensions of the three are 63.7 x 45.9, 63.7 x 45, and 64.3 x 44 mm.
A fresh egg, alone in a nest on La Huaca Islet, Pescadores, December 14, has a somewhat
darker or almost buffy brown ground color, with a heavier surface blotching of a richer and more
reddish brown. It measures 60.7 x 45.2 mm.
Distribution: Coasts of Peru and Chile, from Lobos de Tierra Island (6° 25’ S.) southward to
Coquimbo. (Fuegian and Falkland Island records are erroneous. )
The distribution of the ‘‘Simedén,"’ as this gull is called along the coast of
Peru, has evidently been subject to considerable misunderstanding. Several
recent works, including such authoritative books as those of Dwight (1925,
158) and Alexander (1928, 129), state that the species occurs at the Falkland
Islands, and along the west coast of South America from Cape Horn northward.
Such statements are due merely to the repetition of error, for the Simeon is, as
a matter of fact, an endemic species of the Humboldt Current littoral, found
only along the prevailingly desert shores between the neighborhood of Sechura
Bay, Peru, and Coquimbo, Chile. Hellmayr (1932, 409) correctly says that the
1054 OCEANIC BIRDS:-OF SOUTH AMERICA
species is of relatively rare occurrence in Chile. The southernmost record
appears to be based upon an example collected by Admiral Markham at Co-
quimbo, during the month of November, and now in the British Museum
(Saunders, 1896, 227).
Allegations regarding the occurrence of the Simedn in Magellanic South
America are based upon sight records and resulting misidentification. That such
mistakes are hard to avoid is indicated by references in Beck's journal to sup-
posed Belcher’s Gulls feeding off Ancud, Chiloé Island, during April, 1914, and
to others observed at Ushuaia and Magallanes, during the same month and
also in July. No specimens from these parts of the coast exist, however, in his
collections, and the mystery is apparently solved by an examination of skins
of Leucophaeus scoresbii in juvenal garb. Young Dolphin Gulls in the plumage
of the first winter are very gray and have a broad subterminal band on their
tails. For these and other reasons they bear an extraordinary superficial resem-
blance to Larus belcheri, the differences relating only to such scarcely perceptible
details as the slightly larger size of the latter species, and the shapes of the bills.
No doubt this close resemblance is responsible for the many published records
of Belcher's Gull from Patagonia and the Falklands.
The Simeon belongs to the subgenus Adelarus, as recognized by Dwight, and
its affinities are with the three gray species inhabiting, respectively, the coasts
of Peru, the Galapagos Islands, and the west coast of North America; besides
this, it shows indications of relationship with several Old-World species,
including Larus crassirostris of the Pacific coast of Asia. Such ties are indicated
by morphological details, and more particularly by the pattern of plumage in
both adult and immature stages. Larus crassirostris, modestus, and belcheri, the
last two of which belong to the west coast of South America, are the only
members of their genus which retain banded tails in the adult stage of plumage.
In the course of the Brewster-Sanford Expedition, Mr. Beck collected an
excellent series of young and adult specimens of this gull at Ancén, Peru,
during April and May, 1913. There was no example in breeding state at this
season, and the post-nuptial moult of the quills was in full progress. Among
some examples the entire wing is made up of short primaries which have not
completed their growth, while in others one or two exceedingly worn outer
quills remain. Six weeks after Beck’s work at Ancoén, or about July 1, his
notes from the Pisco Bay region state that the Belcher’s Gulls were then begin-
ning to show the white heads which heralded the coming of the nesting season.
During my own two periods of field work along the coast of Peru, I en-
countered the Sime6én at many localities between Lobos de Tierra Island in the
north and the port of Islay in southern Peru. I discovered also that it nests on
islets off the coast, always in low situations, close to the breaking waves. The
three eggs are laid during November or December, and nests containing eggs or
very young downy chicks were found at the smaller islets of the Pescadores
group, off Ancén, during the middle of December, 1919. None of the nests
was more than about 3 meters above mean sea level. The walls of gorges of
small islets which had split in half were favorite sites, and on one islet known
BELCHER’S GULL 1055
as Pantacabra a number of nests, lined with a few feathers, were so close to-
gether that the aggregation made a sort of small colony.
The southernmost nesting locality I found was at Vieja and Santa Rosa
Islands, at Independencia Bay where, during the middle of November, 1919,
these gulls were extremely abundant. At San Gallan, the Chinchas, and other
islands in Pisco Bay, at Asia Island, at Mazorca and its neighbors of the Huaura
group, the Simeén was pestiferously in evidence in colonies of the guano birds
during the entire period of my field work between October and January. In
its depredations it showed a clear preference for the eggs of newly hatched
chicks of the Peruvian Cormorant or Guanay. At Lobos de Afuera and Lobos
de Tierra in January, I found it in relatively small numbers as compared with
those of the larger Kelp Gull (dominicanus). The fishermen at this island called
belcheri the ‘‘Gaviota,’’ which means merely gull, to distinguish it from its
larger cousin, the ‘‘Cleo.’’ True to its habit of preying chiefly upon the Guanays,
Belcher’s Gull was in special concentration at the Canevaro Peninsula of Lobos
de Tierra, which was the site of the only extensive cormorant colony at the
time of my visit. Here numbers of the gulls were always engaged in their
nefarious plotting to steal eggs, while the Cleos were dividing their equally
destructive attention indifferently among cormorants, pelicans, and the two
species of boobies. Throughout the guano islands of Peru, the Simeon is gener-
ally regarded as the most serious enemy of the guano-producing birds. The
Administration maintains at most of these islands a corps of sharpshooters,
and I was informed that during February and March of the year 1917 more than
5000 predacious gulls, the vast majority of which was undoubtedly of this
species, had been shot at the islands between Pachacamac and Santa Rosa. In
view of this, the following analysis of stomach contents of Larus belcheri, as
determined through the courtesy of the United States Bureau of Biological
Survey, will be of interest. All of these represent birds shot by the Indian
guardians at South Chincha Island during the afternoons of October 12 and 13,
1919, and at Santa Rosa Island during the early morning of November 15, 1919.
—
Sromacus FROM SANTA Rosa IsLtanpD
16 full. Percentage of animal matter, 100. Contents: Fish flesh, bones, eye-lenses, 88 ie
several feathers of cormorant, apparently P. bougainvillii and 1 of penguin (Spheniscus humboldti),
11 °/°; bits of squid mandible, 1 °°.
ty full. Percentage of animal matter, 100. Contents: Remains of young cormorant, 88 ie
bones and eye-lenses of small fishes, 12 °/°.
jy full. Percentage of animal matter, 100. Contents: Slight remains of cormorant, 65 o/e=
a few bits of fish bones, 10 °/°; 2 crab chelae (Cycloxanthops sexdecimdentatus), 15 °/°; pieces of
Chironid, 10°/°.
Sromacus FRoM SoutH CuincHA IsLanD
2¢ full. Percentage of animal matter, 100. Contents: Remains of sea-urchin, 6 °/°; ground
up Engraulidac, 92 °/°; a few feathers, probably of Phalacrocorax, 2 °/°; skin of small fruit, trace.
14 full. Percentage of animal matter, 100; of gravel etc., 4. Contents: Feathers, etc., of
* Phalacrocorax, 40 °/°; remains of small fishes, 60 °/°.
Full. Percentage of animal matter, 100. Contents: Remains of eggs and young of Phalacro-
corax, 100 °/°.
1056 OCEANIC BIRDS OF SOUTH AMERICA
V4 full. Percentage of animal matter, 26; of vegetable, 74. Contents: Fragments of a sea-
urchin, 20 °/°; bits of an immature bivalve, trace; otolith and a few vertebrae and scales of fishes,
4 °/°; cormorant feathers, 2 °/°; vegetable débris, 74 °/°.
14 full. Condition of gullet, nearly empty. Percentage of animal matter, 100; of gravel, etc.,
10. Contents: 8 Bird flies (Pseudolfersia sp.), 30°/°; a few feathers, apparently Phalacrocorax, 30°/°;
bits of fish bones, 40 °/°; small univalve, trace.
Full. Percentage of animal matter, 100; of gravel, etc., 1. Contents: Several feathers of
Pelecanoides garnotii; remains of bird egg, probably of same species, 96 °/°; slight remains of small
fishes, 4 °/°.
26 full. Percentage of animal matter, 100; of gravel, etc., 1. Contents: Several feathers, appar-
ently of Pelecanoides, 30°/°; remains of bird eggs (yolk), 60 °/°; slight remains of small fishes, 10 °/°
Full. Percentage of animal matter, 100. Contents: A few feathers, apparently of Phalacro-
corax, 4 °/°; remains of fishes, 96 °/°.
Full. Condition of gullet, full. Percentage of animal matter, 100. Contents: Remains of an
egg of Phalacrocorax, also a nestling of same genus, to which were attached (on the thighs) 3
Mallophaga (Tetrophthalmus incompositus).
1g full. Percentage of animal matter, 100; of gravel, etc., 8. Contents: Remains of a bivalve
with large quantity of byssal threads, 58 °/°; a few eye-lenses and vertebrae of small fishes, 36 °/°;
traces of Phalacrocorax feathers, 2 °/°; bits of squid mandibles, 4 °/°.
34 full. Percentage of animal matter, 100. Contents: a few feathers, apparently of Phalacro-
corax, 20 °/°; fish bones, in part Clupeidae, 80 °/°; bulk of flesh, etc., is estimated arbitrarily and
distributed to the foregoing items.
Full. Condition of gullet, 14 full. Percentage of animal matter, 100; of gravel, etc., 1. Con-
tents: 2 eggs, containing embryos; color of shell and size indicate them to be those of Phalacrocorax.
Full. Percentage of animal matter, 100. Contents: Remains of young Pelecanoides garnotit,
65 °/°; bit of egg (Phalacrocorax), trace; of a Clupeid and another fish, 35 °/°; 1 Mallophagan of the
genus Tetrophthalmus.
Nearly empty. Percentage of animal matter, 100; of gravel, etc., 10. Contents: Oroliths,
vertebrae, etc., of 3 or more fishes, including at least 1 Engraulid, 60 °/°; feathers, etc., of Pele-
canoides garnotit, 40 °/°.
Full. Condition of gullet, 14 full. Percentage of animal matter, 100. Contents: Fish remains,
99 °/°; a few cormorant feathers, 1 °/°.
Full. Percentage of animal matter, 98; of vegetable, 2. Contents: Remains of Clupeidae, 80°/°;
a few feathers, 9°/°; 2 Pseudolfersia sp., 1°/°; fragments of echinoderm, (echinoid), 6 °/°; barnacle,
Dhoy/2stalrren 2) o/c
Full. Percentage of animal matter, 100. Contents: Remains of Clupeidae, 98 °/°; a few feathers,
in part at least from Phalacrocorax, 2 °/°.
Nearly empty. Percentage of animal matter, 100. Contents: A few feathers, apparently of
Pelecanoides, 40 °/°; slight remains of fishes, 60 °/°.
Also the following entire fishes which dropped out of the gullets of several of the gulls:
2 Trachinotus paloma, 1 Engraulis ringens, 1 Sciaenid.
The contents of these stomachs consist, in brief, of remains of the Peruvian
Cormorant, Diving Petrel, and Penguin, the eggs, young or feathers of the
first-named being in excess of traces of any other species. They show also,
however, that even gulls shot in the neighborhood of a colony of cormorants
had done a great deal of food-hunting for themselves, since bodies of many
species of fishes, together with sea-urchins, chitons, crabs, mollusks, and other
animal matter, figure even more strongly than birds.
Not infrequently I observed the Simeén Gulls fishing on their own account,
and I found that they were quick to take advantage of a concentration of Inca
Terns, which is always a sign of the presence of food. Off one of the Chincha
BELCHER S (GULL 1057
Islands on November 25, I saw two of the gulls resting together on the water
close to a sea-lion, about the head of which Inca Terns were hovering. Suddenly
the seal swung toward one of the gulls, snapping its jaws as it reached for it.
The bird, however, had leaped up too quickly, and it at once alighted beside
and grasped a herring which the sea-lion had dropped.
While the Simeén is often seen in company with the Kelp Gull, I have never
observed it following in the wake of vessels as the larger species does every-
where along the Peruvian coast. At the islands, the two birds are often much
in company, and their behavior has many similarities. Both, for example, go
through certain vocal gestures in exactly the same manner. On one occasion
at Santa Rosa Island three or four birds of each species were standing near me
on the guano-covered plateau, and apparently resenting my presence in territory
that they regarded as their own. They would put their bills between their legs
and begin to scream in this backward-looking and upside-down attitude, and
would then raise the head, open the mouth wide, and scream still louder,
sometimes permitting me to approach within 25 to 30 paces before they took
flight, still protesting. On this occasion, as I inspected the birds at leisure
through field glasses, the differences between adults in full breeding plumage
were impressed upon me, and I made the following record of them in my field
notebook:
Larus dominicanus— Larus belcheri—
Pure white on nape and under surface. A pearly gray tinge on these areas.
Primaries white-tipped, and with a spot on
the outermost.
Inner side of wing white.
Bill horn-yellow; lower mandible with sub-
terminal red blotch.
Eyelid orange, bare.
Iris grayish yellow, reticulated; encircled by
a darker ring.
Feet and legs olivaceous.
Tail white, with a few faint gray marks.
Tongue and inside of mouth pale yellow.
Back and wings slaty black.
Primaries entirely dark.
Gray.
Bill rich yellow; both mandibles red-tipped;
maxilla with superior subterminal black
patch.
Eyelid yellow, feathered except at the canthi.
Iris brown.
Feet and legs bright yellow.
Tail broadly banded with black; white-edged.
Tongue and inside of mouth bright orange.
Back and wings brownish black.
This gull apparently lives well in captivity. Although I could obtain no
exact data, I was told that examples at the Zodlogical Park of Lima had thriven
for periods of years. Schlegel (1863, 9) states that one brought to Europe from
a Peruvian guano island lived for five years in the Zodlogical Garden at
Amsterdam.
KELP GULL
Larus dominicanus
Larus dominicanus Lichtenstein, 1823, Verzeichn. Doubl., 2, p. 82 (coast of Brazil).
Names: Southern Black-backed or Dominican Gull; Big Gull at the Falklands; “‘Gaivotao”’
in Brazil; ‘‘Gaviota Cocinera’’ in southern South America; ‘‘Cau-cau,’’ the Araucanian Indian
name, imitative of the notes, is also a native name in Peru where, however, this gull is usually
1058 OCEANIC BIRDS OF SOUTH AMERICA
called “‘Cleo.’’ In early literature the species was listed under marinus and other specific names of
the Black-backed Gull of the northern hemisphere. True synonyms of the name dominticanus are
very numerous and include fuscus, flavipes, littoreus, antipodus, pelagicus, vetula, vociferus, verreauxii,
fritzei, azarae, antarcticus, and pactficus.
Characters: The only large black-backed and wholly white-tailed gull in the southern hemi-
sphere. Its mantle, moreover, is darker than that of any other gull.
Adults (sexes alike): Mantle slaty to sooty black; head, neck, rump, tail, and ventral surface,
including lining of wings, white; wings generally of color of mantle, the scapulars and all of the
secondaries with broad white tips, which together form a conspicuous alar bar; primaries black,
with white apical spots, the outermost with a rather small subapical mirror of variable size and
shape; a light tongue, indicated on the fourth from the outermost primary, becoming more pro-
nounced along the series inward. Iris straw-yellow or gray; eyelid carmine; bill amber, the tip
of the lower mandible carmine; legs and feet greenish yellow.
10 males from South America, the Falklands, South Georgia, and the South Sandwich Islands:
wing, 403-422 (412); tail, 168-185 (174.5); exposed culmen, 46-57 (51.8); tarsus, 63-69 (65.9);
middle toe without claw, 52-56 (53.9) mm.
6 females: wing, 372-404 (389.5); tail, 152-165 (157.4); exposed culmen, 46-53 (49.2); tarsus,
56-70 (63); middle toe without claw, 45-53 (49.7) mm.
The above dimensions are from Dwight (1925, 224), who has studied our entire American
Museum material. Discussion regarding measurements that transcend these limits will be found
in the text below.
The wing-spread of a male from the South Orkneys was 143 cm.; those of four males and females
from Rio de Janeiro ranged between 128 and 142 cm.
The Kelp Gull does not attain its adult non-nuptial plumage until the fourth winter of its life.
The sequences, which resemble those of other large gulls, have been reported upon in beautiful
detail by Dwight, and are summarized upon the basis of South Georgian specimens by Matthews
(1929, 581), as follows:
In the first winter the plumage is grey-brown with buff specklings; the bill with white tip;
legs, brown, feet grey, darker toward the edge of the web; claws black. The iris is dark brown
and the feet grey. The second winter the grey-brown plumage is heavily spotted with buff and
white and the mantle is brown. The base and tip of the bill are yellow and the center is black.
The iris is light brown and the eyelids are dull red. The feet and legs are green-grey, the webs
grey at their margins. . . . The third winter the mantle and wings are black, and the rest of the
plumage is white, except for some scattered dark feathers in the head, neck, breast and tail. The
bill is yellow, the mandible with an orange-red spot and a few small black streaks above the angle
of the gonys. The eyelid is red and the iris light yellow. The feet and legs are yellowish green. . . .
In the fourth year, when the bird breeds, the wings and mantle are black, the rest of the plumage
being white.
The natal down is darker than that of the Herring Gull (Larus argentatus), with more buffiness,
and finer and fewer markings on the back; the spots on the head are clearer, smaller, and more
abundant. Back and proximal half of wing grayish buff, obscurely lined and spotted with dull
clove-brown; rest of wing dull white; head creamy buff with dull black linear spots, median only
on the forehead, in four broken lines on crown, and curving laterally on the nape, lores, and about
eye; ventral surface grayish buff, more buffy on throat and crissum, the breast and chin decidedly
white, with one or two black spots on the sides of the chin (Dwight).
Valette records the body temperature of Kelp Gulls at the South Orkneys as 40.7° C. He gives
the length of the intestines as 143 cm.
The eggs of this gull are highly variable. Werth (1925, 364) once found threc Jf totally different
color in the same nest. Three is the commonest number in a set, but many complete clutches have
only two, and more than two young birds are rarely reared. Bullock found several sets of four eggs
at Mocha Island on November 24, 1932. The shells are thin and relatively tender, and the yolk is
very dark reddish. Gibson (1920, 77) found the average dimensions of large series from the Province
of Buenos Aires to be 71 x 51 mm.
During the Brewster-Sanford Expedition, Beck collected 6 sets of eggs as follows: Peyron
BELP GULL 1059
Island, Chile, December 19, 1914, 3 eggs, incubation begun; nest of dry grass, well built, on rocky
point of island; the nest of a Black Oyster-catcher only 6 meters away. Five sets from East Island,
Falklands, December 10, 1915. At the latter locality the Kelp Gulls had nests of dry grass, kelp,
and other seaweed, on a small rocky islet. Cormorants, Cassin’s Terns, and Pink-breasted Gulls
were nesting on neighboring islands, and Black Oyster-catchers on the same islet with the Kelp
Gulls, and sometimes only a few steps away. All the Kelp Gull eggs were fresh. The sets, no
doubt selected for their variation, are made up of rather uniform-looking eggs within each clutch,
with a ground color varying between olive-buff or a slightly greener hue and buffy brown. The
overlying markings are brown, of variable size and pattern, and mostly well distributed instead of
being markedly concentrated near the larger end. Some eggs have relatively fine speckling, while
in others many of the blotches measure up to 10 mm. in diameter. Measurements of the 6 sets are
as follows:
Peyron Island, 71.8 x 50, 73.7 x 50, 69.6 x 59.1 mm.
East Island, Falklands: 72.2 x 51.9, 68.6 x 51.8, 72.6 x 52.2; 70.6 x 50.5, 73.6 x 50.1; 77.3
x 50.4, 71.9 x 48.1, 74.1 x 50.7; 72.8 x §2.1, 73.4 x 51.4; 74.4 x 51.3, 72.8 x 51.9 mm.
Eggs from northern Peru, and many other parts of South America, bear a close general re-
semblance to these. The average dimensions of 22 eggs in sets of three and two, collected by
myself at points from Vieja Island to Lobos de Tierra Island, Peru, between November, 1919,
and January, 1920, are 70.7x 48.5 mm. Extreme examples in this series measure 70.1 x 47.5,
75.4x 48.7, 70.3 x 59, and 66.7 x 48.8 mm.
Distribution: Circumpolar in the southern hemisphere and breeding at practically all of the
sub-antarctic islands, including Gough and the Tristan da Cunha group; also at the islands of the
Scotia Arc, and southward into the West Antarctic Archipelago. The species nests likewise in
New Zealand, along the southern coasts of Africa, and on those of South America from Cape
Horn northward to the vicinity of Cape Frio on the Atlantic side, and to the island of Lobos de
Tierra, Peru, on the west, from where it strays casually northward to the coast of Ecuador.
This handsome black-backed gull, the largest member of its family in South
America, has one of the most extensive ranges among sea birds. Not only does
it encircle the globe throughout a broad sub-antarctic belt, but it also nests in
the American region from the vicinity of Marguerite Bay, in the Antarctic
Archipelago (Gain, 1914, 185), northward through successive climatic zones
to Lobos de Tierra Island, just off the burning shores of the northern Peruvian
desert. The length of this breeding range amounts to approximately 60 degrees
of latitude, which is almost or quite without parallel, and is all the more note-
worthy because the entire distance lies on the same side of the equator. True,
Fleming (1924, 139) has described the Kelp Gull of the South Shetlands as a
distinct race from the bird breeding in South America. After examining a very
large series from many localities, however, I am compelled to agree with
Dwight (1925, 223) and Wetmore (1926, 131) in concluding that the alleged
differences have not yet been shown to be constant. Moreover, if there are two
subspecies, there are equally likely to be others and, pending a revision of the
Kelp Gulls from all parts of the southern hemisphere, I prefer to treat them as
an undifferentiated unit.
Wetmore has pointed out the very close similarity in color and structure
between this gull and Larus marinus of the North Atlantic. He regards the two
as representative of each other, and even considers the propriety of grouping
them as subspecies. Dwight, on the other hand, emphasizes the relation of
the Kelp Gull with the Larus fuscus assemblage of the northern hemisphere, the
fundamental kinship showing in immature no less than in adult stages of
1060 OCEANIC BIRDS OF SOUTH AMERICA
plumage. Considering such implied differences of opinion, it is clear that much
work remains to be done on problems concerned with the intricate valences
within the gull family, a condition apparently produced through respectively
accelerated and retarded rates of evolution of color, pattern, and plumage
sequence in the different phyla of these birds. The situation also points out the
folly of attempting to indicate the finer degrees of relationship by means of
zoological nomenclature in advance of more thorough study than has yet been
carried through.
The American Museum possesses a very large series of South American Kelp
Gulls, obtained during the Brewster-Sanford Expedition, during my own field
work at South Georgia and along the Peruvian coast, and from many other
sources. This material is listed below in geographic order, beginning in Brazil,
working southward to the Antarctic Archipelago, and thence northward along
the Pacific coast of the continent.
Brazil: Rio de Janeiro, 4 specimens, June (Cleveland Museum Expedition).
These are presumably to be regarded as topotypes of the species, especially
since this gull nests or formerly nested at the islets of Raza and Redonda, at the
entrance to the harbor of Rio de Janeiro (Wied, 1833, 850).
Argentina: Mar del Plata, immature and sub-adult stages, September and
October; Rio Gallegos, August and September; Ushuaia, July (all collected
by Beck).
Falkland Islands and political dependencies: Port Stanley, Port Louis, and
other localities, breeding birds and younger stages, November, December, and
January (Beck); South Georgia, representative series, December and January
(Murphy and Correia); Deception Island, South Shetlands, 6 specimens, young
and adults, December and February (Bennett).
Chile: Hoste Island, December; Magallanes (Punta Arenas), a series, Febru-
ary and July; Chiloé Island, a series, May and June; Corral, flying birds of all
ages, September (Beck); Mocha Island and Temuco, Cautin, several specimens,
November (Bullock); Tofo, several specimens, February (Hallinan).
Peru: Independencia Bay, one breeding male, November (Murphy); Ancon,
adults and young, May (Beck); Lobos de Tierra Island, January (Murphy);
Talara, full-plumaged adults, January (Murphy and Heilner).
Ecuador: El Muerto Island; adult male, February (Murphy and Heilner);
Puna Island, July (Chapman).
These birds, considering the great series of adults as a whole, show an
individual range in the color and form of the bill beyond anything that I can
correlate with locality, age, or the well-marked differences of size between the
sexes. Irrespective of any of these qualifications, many birds show, for example,
an extremely pronounced gonydeal angle, which results in a bill form approach-
ing that of the Dolphin Gull (Lewcophaeus), or even of Gabianus pacificus of the
Australian region. Wetmore has called attention to the sporadic appearance
of this character in Kelp Gulls from both Kerguelen Island and South America.
I find that in several birds from Peru and from South Georgia the feature is very
strongly marked, and yet is not shared by other examples taken at the same
KELP GULL 1061
places and dates. A drawing of a specimen of this type is reproduced herewith.
The condition indicates, I judge, that a deep mandible and pronounced angle
are inherent traits among certain gulls of the Larus group, attaining maximum
development and fixity in such forms as Gabianus.
It is possible that a true geographic variation may be shown by the color of
the iris in adult Kelp Gulls. In the field I recorded the hue among South Ameri-
can birds as ‘‘stone-gray,’’ and some of Beck’s labels bear the notation ‘‘whit-
ish."’ Among a number of antarctic specimens, however, the iris is recorded as
“light yellow.”’
Dimensions of specimens are confusing, because individual variation is so
great that it makes one cautious about drawing geographic conclusions. Mea-
surements less than or greater than those shown
among the sixteen specimens selected by Dwight
crop out among birds from various localities.
Thus a male from Nightingale Island, Tristan da
Cunha, has an extremely long wing (447 milli-
meters), all its other measurements, however, fall-
ing close to the averages given above. Two males
from Rio de Janeiro have wings slightly shorter
than Dwight’s minimum, namely, 395 millimeters. =
An extraordinary bird is a huge-billed male shot Fic. 78. Bill of Kelp Gull, 3,
by myself at Talara, Peru. It was in breeding con- WollastonIsland, near Cape Horn;
dition and generally resembles other males from ‘° illustrate theideep goaydeal
: : : angle occasionally exhibited by
the same region, though both its bill and tarsus this species.
are of unmatched size. append its measurements,
compared with those of two males from other localities. Abundant corre-
lated material indicates, nevertheless, that these differences are individual
rather than geographic.
Bill from | Width of Middle toe
Culmen e Tarsus
gape maxilla and claw
o, Deception Island, December 15 . . 53.7 66.6 19.7 66.2 55.8 mm.
o&, Chiloé Island, January 20. .... 58.8 72 22.9 71.2 61
Goilalara December7I5\*. -- © 2. ss 61.5 81.3 26.1 HT 68.6
While the specimens listed above give a skeleton of the South American
range of the Kelp Gull, there are, of course, innumerable records which piece
out and slightly extend the distribution. The species is recorded from many
localities on the coast of Brazil, and Friedmann (1927, 164) found that in late
August his steamer was never without an escort of Kelp Gulls during the voyage
between Rio de Janeiro and Buenos Aires. According to Alvarez (1933, 8),
this gull is common all the year along the Uruguayan coast, nesting during
September and October on Flores and Gull Islands. In Argentina it occurs far
inland as well as at the seashore, particularly during the winter season when
Wetmore observed examples nearly 200 kilometers from the ocean. Probably
the presence of stockyards and killing-pens had been an inducement to draw
1062 OCEANIC BIRDS OF SOUTH AMERICA
Kelp Gulls away from salt water, although they doubtless bred round the shores
of some of the Andean lakes in western Patagonia even before the settlement
of the country. Breeding stations about fresh water are, in fact, not uncommon
throughout the southern portion of the continental range, as testified by a
colony Peters (1923, 292) found on a rocky island in Lake Nahuel Huapi, and
another recently discovered by Reynolds (1934, 352) near a cormorant colony
on Lake Yewin, Tierra del Fuego. Beck saw many Kelp Gulls on December 20,
1914, high up under Diadem Mountain, Tierra del Fuego, about a small Jake,
where some were bathing in puddles on the ice. At Deceit Island, near Cape
Horn, he found eight pairs nesting on two islets in a pond on flat land, below
the breeding ground of the Sooty Shearwaters. The Kelp Gull is, in fact, indif-
ferent to the nature of available water, whether salt or fresh, and is equally at
home in regions of constant rain and snow or at sun-baked Peruvian islands
which receive not a drop of precipitation for years on end.
Along all coasts of South America the breeding range of the Kelp Gull seems
nowhere to be continuous, but to be particularly dependent upon a combination
of local conditions, as determined by the accessibility of a food supply, or by a
site which offers the nesting gulls full protection from their natural enemies.
On the great mud flats of the Rincones, near Cape San Antonio, Argentina, for
example, these gulls find a sufficiently inaccessible retreat on the mainland, in
a district honeycombed by the burrows of crabs and overgrown with patches
of glasswort. On one side are the dunes of the Atlantic coast, and on the other
the treacherous and unfrequented shallows of the Plata estuary. It is the mud
of the “‘cangrejales,"’ however, which here offers the best protection to the
birds. High continental headlands, islets in steep-cut estuaries, shores protected
by cliffs and close to water of sufficiently low temperature to support growths
of giant kelp, also make favorite nesting localities. Along the west coast of
South America the gulls themselves are to be seen almost everywhere, and yet
their nesting stations may be far apart. Mocha Island, which is well off the
Chilean coast, Santa Maria Island in the Bay of Arauco, and Quiriquina in the
Bay of Talcaguano, all offer such safe havens as I have described, and are all
occupied by at least a few pairs of Kelp Gulls, which nest in close proximity to
each other even though they may not form a true ‘‘colony.’’ The high land-
ward slope of Vieja Island at Independencia Bay, Peru, likewise furnishes a
favorable environment, and here on a spit of shingle, with a bulwark of kelp
growing only a short distance offshore, I found nests during November, 1919.
San Gallan Island, and San Lorenzo, the shelter of which creates the roadstead
of Callao, are also constant breeding grounds. I found no nests at any of the
very small Peruvian guano islands, but the large yet low Lobos Islands are
overrun with the Kelp Gulls, particularly Lobos de Tierra, which appears to be
one of the world’s centers of abundance of the species.
In view of the vast environmental differences in the habitats of Kelp Gulls
within the South American region, I have thought best to treat separately the
life history of the species at the tropical Lobos Islands, before continuing the
general account of the birds occupying the pan-antarctic zone.
EELP GULL 1063
At Lobos de Afuera, on January 5, 1920, I found the Cleo, as it is here called,
extremely abundant, to the great detriment of the guano birds, upon the eggs
and chicks of which the gulls pounced as soon as they were uncovered. At this
island and at Lobos de Tierra, where I subsequently made a longer stay, I was
impressed at once by the fact that in a region of all-year-round nesting, the gulls
had become largely parasitic creatures, the subsistence of which was gained at
the expense of cormorants, boobies, and pelicans. The gulls had altogether
departed, moreover, from their sub-antarctic régime, and had themselves
adopted a more or less continuous breeding season, so that they were enabled to
feed their own offspring throughout the year upon the produce of despoiled
nests. Wherever I walked on the Lobos Islands I was invariably followed by
a host of gabbling, screaming Cleos, which became even more vociferous when
their young ones were approached. They all behaved as though perfectly aware
of the fact that sooner or later I would unwittingly startle an unfortunate guano
bird from its nest. The eggs of boobies they would carry away to devour,
sometimes swallowing them entire, while those of pelicans they would break
upon the ground. Even the eggs of their own kind were not immune; they
would carry them off as soon as an incubating gull was flushed and, when I
threw some heavily incubated Cleo eggs on the sand, cracking them, the canni-
balistic old birds flew down and gobbled up the embryos.
At Lobos de Tierra the Kelp Gull breeds, like its abused neighbor the Blue-
footed Booby, in every part of the island, from just above high watermark to
the slopes and summits of all the little hills. The nests are attractive structures,
made of several species of marine algae, most of them red, yellow, purple, or of
other bright colors. The exquisite black and white gulls sitting upon them
are conspicuous from afar, and it may be in direct correlation with this fact
that they flee the nest at once upon the approach of a human being.
I found nests on the sand of the beach, in the seaweed of the higher drift
lines, inside an old basket, on the pebbly pampa of the interior, in the talus of
steep banks, and on the sharp ridges of stony outcrops far back from the water.
Some of them had neither eggs nor chicks, but most contained one, two, or
three, sets of the last number being in every stage of development. Downy
chicks, and young birds of all ages up to full-grown gray-brown fledglings,
were about as numerous as eggs. Chicks of whatever size left their nests when
a man approached, but some of them, when watched from a distance, were
seen to return to them later, provided they escaped the savage lunges that every
nesting booby would make toward them. The chicks had one trick never at-
tempted by their parents, namely, that of squatting down among the stones, or
““freezing,’’ thus taking full advantage of their obliterative pattern. It is an
interesting biological fact, concerned no doubt with the rigors of natural
selection, that such reactions become eliminated from the behavior of a bird at
an age when they would cease to be effective. If the young Kelp Gulls were
surprised when near the beach, they would at once take to the open ocean—
even the tiniest downy chicks—and swim out, to remain afloat until the fancied
danger had passed.
1064 OCEANIC BIRDS OF SOUTH AMERICA
The adult Cleos gathered in droves along the sandy beaches close to the
Indian fishing stations at Lobos de Tierra, and every evening clouds of them rose
into the air and hovered about the returning sloops and schooners of the fisher-
men, eager to pick up scraps from the cleaning of the day's catch. I believe,
also, that the gulls undertook more or less fishing for themselves as a variation
from their diet of eggs and nestlings, because I frequently encountered them
singly, or in loose flocks, far out over the ocean, scouring about and occasionally
descending to ruffled patches of surface that indicated a concentration of fishes
or swimming crustaceans.
I had no way of estimating the numbers of Cleos at Lobos de Tierra and Lobos
de Afuera, but I judge that the islands had fully as many of these gulls as they
were capable of supporting, and that there is perhaps no other area of equal
size that is the home of so many.
Migratory movements of the Kelp Gull seem to be largely dependent upon
latitude. Throughout the milder portions of the range, particularly where, as
in northern Peru, the nesting period of the species as a whole is continuous, the
migration is doubtless irregular and sporadic, and likely to lead the wandering
birds in either direction along the coast. For this reason, no doubt, I saw
numbers of the gulls at E] Muerto and Puna Islands, and even on exposed mud
flats opposite the water front of Guayaquil, during January, 1925. A month
later I observed others in the Bay of Santa Elena, north of latitude 2° S. Chap-
man (1926, 189) reports the species on the Jambeli coast and elsewhere in the
Gulf of Guayaquil at the opposite season of the year, or during July, August,
and the first half of September. At the Falklands, according to Abbott (1861,
165), a good proportion of the Kelp Gulls depart during the winter. We have
no indication, however, as to whether these birds migrate to sea or go to swell
the half-terrestrial winter population on the continent. At South Georgia the
majority of the Kelp Gulls certainly remain in residence throughout the year,
and at all times the species obviously clings to the bays and the coast rather
than venturing far out to sea. One rarely or never finds a gull on the offshore
whaling banks, where skuas and petrels are so abundant. But in the polar lands
of West Antarctica the species is definitely migratory, although it is not certain
whether it travels into distant parts of the open sea or merely clings to the
northerly border of the pack-ice. According to Gain (1914, 102), most of the
gulls go north after April, but a few single birds always remain in the ice.
Members of the Swedish Antarctic Expedition saw no Kelp Gulls at Snow Hill
Island between March 4 and September 21, although at Paulet Island and in
Hope Bay examples appeared several times during the winter. At the South
Orkneys, Valette (1906, 55) also found that one or two of these birds might
occasionally put in an appearance during the winter, but at the South Shetlands,
according to Lester (1923, 174), the gulls absent themselves completely during
the dark and frigid season of the year, returning shortly after the homeward
migration of the Gentoo Penguins and in advance of the skuas. The point
appears to be that the Kelp Gull is a generally sedentary species at isolated
islands, such as South Georgia and Macquarie (Ainsworth, 1915, 195), or wher-
KEEP? GUCL 1065
ever the climatic conditions permit. At the Falklands the birds probably dwell
close enough to the continent to find their way to regions of richer forage,
while at the polar islands they necessarily move away for a part of each year.
It is possibly because of such enforced migration in the Atlantic that the species
originally reached such far-away spots as Gough and Tristan da Cunha, from
where Verrill (1895, 450) and Wilkins (1923, 499) have recorded it. Although
this gull is not common about the Tristan group, the ‘Quest’ party obtained a
specimen in juvenal plumage at Inaccessible Island, on May 21, and saw many
others, all of which were larger, and of an older and lighter phase, than those
obtained at South Georgia. In the British Museum I have examined examples
from Nightingale Island.
Despite the fact that the Kelp Gull has reached such remote islands as those
just named, it is noteworthy that it has never been recorded from Juan Fernandez
in the Pacific. That the latter islands would make a suitable environment is
indicated by the presence of the Magellanic Penguin and other sub-antarctic
birds, and by the fact that Mas Atierra is visited at times by such Fuegian
coastal species as the Black Oyster-catcher. Juan Fernandez, however, lies to
windward of the continent, in addition to which the Kelp Gulls of the opposite
mainland shores occupy an environment from which they are never forced by
inclemency of weather to migrate. The most distant land from the west coast
of South America at which they have been observed appears to be the little
islets of Hormigas de Afuera, off central Peru.
At South Georgia the Kelp Gulls were already breeding and were very active
and noisy, when IJ arrived at the island in late November, 1912. They frequented
both the seacoasts and the pond-dotted, grassy valleys beyond the heads of the
fiords. They were much shyer than most of the native birds, making, in this
respect, a particularly strong contrast with the skuas, for at the approach of a
man most of them would fly to the screes of the surrounding slopes and watch
until the trespassers among their lakes had passed by. Nest-building had started
in October, the Kelp Gulls probably being among the earliest breeders at South
Georgia (Matthews, 1929, 581). I found nests with well-incubated eggs or
newly hatched chicks during late November and the first half of December.
These were in a wide variety of sites, including promontories above the sea,
glacial moraines, back beaches, and particularly on grassy islands offshore,
such as those at the Bay of Isles.
At South Georgia the gulls usually congregate in colonies of several dozen
pairs. The nest is made of tussock grass, moss, dried kelp, bits of whalebone,
and a few feathers, and is situated on the ground amid grass or in bare places,
usually on a rise or on top of a boulder. Most eggs, according to Matthews, are
laid soon after the beginning of November, although others appear well into
the next month.
On December 3,1 found many young downy chicks, and all the eggs examined
were advanced in incubation. A month later, fledglings were everywhere, all
able to swim strongly, but not yet capable of flying far. They were wary, and
were very skilful in keeping the width of a pond between themselves and a
1066 OCEANIC BIRDS OF SOUTH AMERICA
Fic. 79. Left, the four-year plumage cycle of any large gull that breeds in the northern
hemisphere, e. g. Larus argentatus. Right, the same cycle of any large gull that breeds in the
southern hemisphere, where the seasons are reversed, e. g. Larus dominicanus. Solid lines repre-
sent periods of stable plumage, broken lines periods of moult.
From Dwight (1925).
pursuer. I found that all the Kelp Gulls of a colony seemed to take a proprietary
interest in every young bird. Whenever I approached one of the latter, the
adults would circle overhead, screaming until the fledgling took wing, but,
although they made a great deal of noise, they did not attempt actively to
protect their offspring, as the skua does with so much determination and
abandon. The outcry of the adults is one of protest rather than of effective
defense. As Hall (1900, 10) says, ‘‘The young crouch on the rocks for evasion
when a human being passes, and the whole flock call from above as if they had
the melancholies."’ At this stage, as well as earlier, while they are still in the
nest, the chicks need constant protection from the skua. They have a piping,
trilling whistle, very snipe-like and quite unlike the voice of the old birds.
They are quick to give the note of alarm, to which the old gulls as promptly
respond, making a great commotion when a skua actually flies over their oc-
cupied ground. Curiously enough, however, they pay no attention, as Vallentin
(1924, 302) points out, to an enemy that has passed out of their territorial
zone, even though it may be engaged in tearing to pieces and eating a young
gull within plain sight. On one occasion, at South Georgia, I saw a skua badly
worsted by the gulls. The marauder flew over a pond close to where two chicks
were swimming, whereupon first three and then four old gulls pitched into it,
knocked it down to the water, and then piled upon it and continued to peck
and pound it vigorously. It was some time before the skua could collect itself,
beat off its enemies, and fly away. On another occasion I saw a skua high in
the air flying ignominiously before a pair of gulls, which swooped down upon
it repeatedly until the foe finally outdistanced both.
I noted the first youngster in flight on January 11, and by January 29, flying
fledglings were common. As soon as the chicks have reached this stage, the
KELP GULL 1067
gulls gather in flocks, mostly spending the nights afloat on the surface of ponds,
and standing about during the daytime in groups of forty or fifty on the glaciers,
cliffs, or beaches, always with their breasts turned toward the wind. South
Georgia is a region of sudden meteorological changes, and the gulls make
excellent weather vanes, for as the wind veers, whether gradually or rapidly,
the gulls, too, change their direction. They sometimes fly very high, especially
during a tempest, and have been seen at an altitude of 1500 meters (Gain, 1914,
106). As violent puffs begin to blow, the birds often leave the beaches to settle
on the water in the lee of the long lines of growing kelp, which serve them as
a breakwater. Sometimes they stand on the kelp itself, the weight of their
bodies causing the strands to sink until the feathers of their bellies touch
the surface.
The growth of the fledgling to full strength appears to be very gradual.
Up to the end of the South Georgian summer period, at least, the birds in the
youthful gray plumage seldom if ever accompany their elders on foraging
flights to the middle of the great fiords, or over the snow-covered glaciers and
headlands to distant inlets of the coast; rather, they cling closely to the place
of their nativity and lie low when the gales break. At this stage the young
have a peculiarly long-legged appearance and they can cover the ground very
rapidly.
Distrustfulness seems to be a strongly marked temperamental character of
the Kelp Gull. Whenever at South Georgia I was bent upon stalking a sleeping
albatross or seal with a camera, and was at the point of accomplishing my
object, a self-appointed sentinel in the form of a gull would be almost certain
to fly by and to warn my prospective subject with its annoying cackle. But
while the gulls would render me no assistance, they were always ready to
profit from the slaughter of sea-elephants by members of the crew of the brig
‘Daisy.’ Even at such times, however, their reactions would be very different
from those of the skuas, which gathered with them, for the gulls would sit
about at a distance, waiting for the coast to clear, while the skuas would hustle
forward and, as the skipper of my vessel expressed it, ‘take a hand with the
men in a bit of skinning.’’ Later, when gulls and skuas were none too amicably
sharing the remains, the latter would stay calmly on the job if I rejoined
their party, while the gulls would retreat to the nearest rise of ground, or to
the kelp fields a stone’s throw out from the beach. Matthews states that the
gulls become very much less wary about the whaling stations during the long
South Georgian winter, when the meadows and beaches are deeply buried
under snow.
At the Falklands the Big Gull, as it is called, usually breeds in large rookeries,
a habit which offers some protection against the skua; nevertheless, solitary
nests are also known there. The location of the colonies is either inland,
among the diddle-dee, or on the beaches. If the latter, the lee of a log of drift-
wood or a whale’s bone is often used as a protection against the grit-bearing
winds. Sheep's wool, gleaned from the shrubbery, often enters into the material
of Falkland nests, which are composed mainly of grass and seaweed (Cobb,
1068 OCEANIC BIRDS OF SOUTH AMERICA
1910, 69). The groundsel, Senecio vulgaris, grows luxuriantly about the gull
colonies, probably resulting from the natural sowing of seeds which had
adhered to the gull feathers (Vallentin, 1924, 302). At the Falklands the eggs
are collected for human food in December, and as many as possible of those not
taken are smashed, because of the injury this gull does to the sheep industry.
The thin and relatively tender shells of Kelp Gull eggs make them difficult to
transport. Furthermore, the dark reddish color of the yolk is somewhat preju-
dicial to their appearance, though they are good to eat, whether boiled,
fried, or cooked in flapjacks (Cobb, 1910, 68; 1934, 41).
At the South Shetlands, as at South Georgia and the South Orkneys, the
breeding season is somewhat earlier than at the Falklands. Bennett (1920, 26)
states that November 10 is about the earliest date for completion of the sets
of eggs, and that if these are taken, the birds will promptly replace them. By
the end of September the gulls come in numbers to the South Orkneys (Valette,
1906, 55); birds have been seen pairing on November 3 and the earliest eggs are
recorded on November 15 (Clarke, 1913, 242), the sets of three all being com-
pleted by the middle of December. Clarke states that fresh eggs marked on
December 3 were found chipped on December 28, indicating an incubation
period of 25 days. The nests are sometimes simple depressions in the ground,
without lining. Because the shells of Kelp Guil eggs are so delicate, they are
not infrequently dented or cracked by the roughness of the stones on which
they are laid. Nevertheless, that young birds hatch from these broken eggs
has been many times observed (Bennett, 1920, 26). Bennett (1930, 13) also
speaks of the Kelp Gull as the “‘gardener of the antarctic.'’ The nucleus of
every patch of grass in West Antarctica, he states, was once a gull’s nest. In
constructing the nests, the gulls pull up wisps of grass by the roots. Some of
this survives, and benefits not only from the manuring but also from the bodily
heat of the sitting bird, and such stalks as take root on the outer wall of the
mest undergo more than the ordinary amount of growth. The gulls breed,
however, well to the southward of the limit of vascular vegetation in West
Antarctica, and at Trinity and Valdivia Islands nests built of moss have been
found upon a foundation of snow. Gain (1914, 102) saw similar nests south
of the antarctic circle, constructed of mosses, lichens, and feathers, and con-
taining either two or three eggs. In these high latitudes, nest-building begins
before the middle of November and the first eggs have been reported on Novem-
ber 20. At the South Shetlands well-grown young have been found by Bennett
as early as December 20.
At Kerguelen, Kidder (1875, 13) noticed that at the beginning of the mating
season there was a tendency for these gulls to congregate and fly about high in
the air, making considerable outcry. On November 19, Werth (1925, 564)
several times saw that, in a large group, one bird appeared to be following
another, possibly in courtship.
The voice of the Kelp Gull has a considerable range of expression. The birds
utter a variety of cackling and laughing notes, reminiscent of those of many
other species. While standing quietly but watchfully on the rocks, they utter
REL? GULI 1069
a conversational note of low pitch, which sounded to me like the words “‘Katy-
did’ and ‘‘Katy-didn’t,’’ or even more like the sounds produced by the orthop-
terous insect called katydid. Frequently calls that begin as a rapid cackle
change to long-drawn ‘“‘tortured’’ screams; this is particularly true when the
birds are on the ground, thus permitting their outcries to be accompanied by
appropriate gestures. For instance, they sometimes begin their song with the
bill pointing toward the ground between their legs, the head then being lifted
in a succession of jerky movements as the sounds are heightened and prolonged,
the final ear-splitting outcry coming from a widely opened mouth which points
upwards. Gibson (1920, 77), whose observations were made near the mouth
of the Rio de Ja Plata, writes, “The cries also are typical of the species, clamour
of long hoarse calls to each other, loud chorus of inhuman laughter as they
wrangle over their feast, and a high and sad double-note recalling great oceans
and wandering sea-fowl. Sui generis!’’ Buller (1888, 47), in mentioning two
albinos, both pet birds, states that he found that captives of this species re-
sponded to the music of a piano, and that sometimes they would begin a chorus
of screams as if in accompaniment. Incidentally, Kelp Gulls have been kept
for very long periods in captivity, and one female is known to have constructed
her first nest and laid three infertile eggs after leading the life of a lonely pet
for nineteen years (Buller, 1905, 168).
The Kelp Gull has feeding habits of the most diverse kind, its staples depend-
ing very largely upon place and circumstance. Its old mode of life in many
places has been changed by human activities, such as those of shore whaling
stations and plants for the slaughtering of sheep or cattle. For such reasons,
the Kelp Gull is no doubt now vastly more of a scavenger than it was in primi-
tive times. Beck, for example, saw many thousands of these gulls abour the
““frigorifica’’ at Rio Gallegos, Argentina, where more than 300,000 sheep had
been slaughtered and rendered during the three months preceding his visit in
June, 1915. Everywhere in southern South America, the gulls gather about the
killing-pens to share blood and offal with Turkey Vultures and other birds of
prey. The flesh that attracts them most of all, according to many observers,
is that of a horse. Such a carcass, with the hide stripped off, is sure to draw a
large force of Kelp Gulls, whereas a dead cow or sheep might lure only one or
two. Under such circumstances, these birds may remain in possession for a
week, keeping off all other carrion-feeders, and retiring to some near-by pool
only at dusk (Gibson, 1920, 77). In the same way they take advantage of
modern whaling and sealing in the Antarctic; I have seen them alighting upon
inflated whale carcasses straight from sea, as these were being towed into
Cumberland Bay, South Georgia. Whalemen and ranchers alike believe that
the Kelp Gull has a keenly developed sense of smell, because it gathers so
quickly at the spilling of blood. This was also credited by Dr. Gain, but I
know of no trustworthy data bearing upon the subject.
Carrion-feeding is only one step removed from the eating of live stock, and
in Patagonia and the Falklands the Kelp Gull is roundly hated because of its
attacks upon young lambs. Even dogs and cats go in terror of it about ranch
1070 OCEANIC BIRDS OF SOUTH AMERICA
stations. In carrying off eggs or the young of various birds, it is almost as
adept as the skua; in some parts of the range, as at the Peruvian guano islands,
a large proportion of the food is, as already noted, made up of eggs and young
birds. Gain states that during late winter in West Antarctica, when the car-
casses of all the seals that had been killed were deeply covered by snow, the few
Kelp Gulls which had lingered about the human winter quarters took to hunt-
ing the Snow Petrels, although most of the latter proved too quick for them.
The Kelp Gulls are, of course, noted for keeping close to coastwise ships in
search of refuse. From Cape Blanco, in northern Peru, they regularly follow
the steamers southward, often alighting on the superstructure and enjoying a
free passage until garbage appears in the wake. They confine their attention
entirely to coastwise vessels, however, quickly leaving one which heads out
toward the warm high sea. Sharpe (1879, 109) states that the Kelp Gulls soon
become conditioned to such regular phenomena as the striking of eight bells
at noon on board an expedition vessel anchored for a long time in one locality,
this sound always presaging the emptying into the sea of table refuse.
The Kelp Gulls are, however, quite capable of capturing active food for
themselves. Stomachs I examined in the Humboldt Current region contained
fish bones, and in Beagle Channel near Ushuaia, on April 30, 1915, Mr. Beck
saw many of these gulls in pursuit of small leaping fishes which his notes call
sardines. These the birds were capturing easily, picking them from the top of
the water or even seizing them in mid-air. When the gulls fish in this way,
they strike the surface smartly with both feet together, thereby giving them-
selves a forward impulse that launches them again into flight. Frequently,
however, they feed while afloat, tipping up the tail as the head goes beneath,
or even diving with half-spread wings after a short forward leap, so that every
part of them except the ends of the long primaries is completely submerged.
Buller (1888, 47) saw one capture a flounder as large as a man's hand, though
it was unable to swallow it.
To judge by the habits of the Kelp Gulls observed in parts of South Georgia
remote from the whaling stations, the bulk of their natural food—dating from
before the days of human shambles and city dumps—comprises mollusks and
other invertebrates found on the rocks and beaches or in the tangled and barely
submerged surface of the kelp fields. Limpets of the genus Patella hold a high
place in their diet. Every coastal hilltop at South Georgia is more or less
covered with layers and heaps of the perforated limpet shells, as a result of the
gulls’ habit of flying over and over again to the same place to ingest a meal.
Many other invertebrates, including mussels, chitons, sea-urchins, and crabs,
mostly obtained in the intertidal zone, also furnish them with food. The gulls
seem always to be on the alert for the turn of the tide, which will expose their
feeding grounds. Hard-shelled creatures, such as they cannot readily break
with their bills, they drop from a height in the usual gull manner. Oldham
(1930, 239) has published exact observations on the shell-smashing habit of
gulls in general. He found, for example, that the ordinary procedure of Herring
Gulls with whelk shells containing hermit-crabs was for the birds to fly from
BEL P GULL 1071
the intertidal zone to the higher beach, then to run a few steps and rise almost
perpendicularly to a height of six or seven meters, drop the prey, descend, and
tear at it vigorously. If the crash had not broken the shell, the gulls would go
through the same maneuver again. Oldham saw one bird repeat it eight times,
and another ten times. The gulls make no discrimination, however, as to the
type of shore on which they drop their prey. That is, they do not select adjacent
areas of flat rock or hard shingle in preference to soft sand, as is so commonly
believed. Yet they do distinguish between water and land, only rarely making
the mistake of using the former. However, I have seen gulls dropping mollusks
on ice, and have noted that they occasionally erred or miscalculated enough to
permit the shell to fall into adjacent water and be lost. An altitude of between
5 and 8 to 9 meters seems to be fixed by practical considerations, if the bearer
of the prey is itself to become the beneficiary because, as Oldham writes, ‘‘gulls
make no clear distinction between meum and tuum.”"
LAUGHING GULL
Larus atricilla
Larus Atricilla Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 136 (America = Bahama Islands).
Names: A native name at islands off the coast of Venezuela is ‘‘Guanaguanare.'’ Synonyms of
the specific name include plumbiceps, wilsonii, atricapillus, macroptera, minor, catshaei and megalopterus.
Characters: One of the two largest of South American “'black-hooded”’ gulls, the other being.
L. serranus, from which the Laughing Gull differs in its much darker mantle and almost wholly
black primaries.
Adults in breeding plumage (sexes alike): Head completely hooded in dark sooty gray, save for
a conspicuous white eye-ring; nape, lower neck, upper tail coverts, tail, and ventral surface white,
the breast sometimes suffused with delicate pink; mantle and rump deep neutral gray; outer prima-
ries black, all but the outermost sometimes with small white apical spots, increasing in size in-
wards and forming a broad white terminal band on the tips of the proximal feathers; the fourth
from outermost quill usually with a tongue on both webs, making the feather about half grayish;
the inner quills increasingly grayish forming, with the primary coverts, a wing-patch which is
bounded by the black outer webs of three primaries, the tips of two, and the white edging of the
secondaries; primary coverts and alula usually somewhat dusky, or with blackish shaft streaks;
lining of wing gray, the axillars white. Iris brown, eyelid dull red, bill dark brownish red, the
terminal third of gonys carmine; legs and feet dark red. Adults in winter differ chiefly in the absence
of the hood, the head and neck being white, the occipital and auricular regions spotted or mottled
with brownish gray, the eye more or less surrounded by a dark crescent.
16 males: wing, 308-330 (321); tail, 113-133 (122.6); exposed culmen, 37-44 (40.2); tarsus,
50-54 (51.6); middle toe without claw, 33-36 (34.2) mm.
10 females: wing, 295-326 (312.3); tail, 115-123 (118.5); exposed culmen, 35-41 (38.9); tarsus,
46-55 (49.7); middle toe without claw, 31-36 (32.7) mm. (Dwight, 1925, 262).
Younger birds have an imperfect black hood during the breeding season; the mantle is deep
neutral gray but a little browner than in adults; the head in winter plumage is white, with the
occiput spotted or streaked with grayish brown, which forms a partial collar on the nape extending
to the sides of the neck; auriculars, an eye-crescent, and the outer canthus of the eye black, with a
partial white eye-ring posteriorly on each lid. The hind neck is gray, paler than the back. The
white under parts show an inconspicuous dusky gray band on the throat and sides, and an occasional
clouding on the breast. The skin of the eyelid is black, rather than reddish.
In juvenal plumage the mantle is pale clove-brown, with buffy feather edgings which are broad-
est and palest on the tertials and scapulars, the feathers otherwise being brown nearly to their
1072 OCEANIC BIRDS OF SOUTH AMERICA
bases; rump grayer, tail coverts white, concealing the dark gray basal portion of the tail; head
solidly grayish brown; hind neck browner and darker, merging with the back; forehead, lores,
and malar region slightly paler; partial eye-ring gray; ventral surface dingy white, with clouding,
whitest on chin and tail coverts; a broad, ill-defined pectoral band merging into the whitish of
breast; sides of chin distinctly white, usually flecked with brown; primaries black, a faint white
tipping increasing inward, the inner five with dingy gray on the outer webs; secondaries black,
conspicuously white-edged; tertials brown like the back; primary coverts and alula black, faintly
edged with buffy gray, the greater coverts clove-brown with buffy gray edgings; median coverts
more gray; lesser coverts like the back; wing-lining and axillars grayish brown, faintly edged with
buffy gray; tail largely basally gray on outer, and white on inner, webs, with a very broad terminal
blackish band narrowly tipped with buffy white; outermost rectrices with a narrower band, and
outer web often gray to tips.
In natal down the back and wings are dingy buff, with clove-brown markings in distinct,
rather narrow lines; on the head the brown markings are broken up into numerous small spots;
the ventral surface is paler but with obscure dusky fleckings on the sides, and clearer dull black
spots and lines on the upper throat and chin; buffy lower throat and paler abdomen, immaculate.
Eggs: Usually three but not infrequently four; highly variable in shape but most commonly
ovate. The ground color varies from cream-buff to wood-brown, more prevailing types of eggs
being olive buffy or rarely olive-green. The markings consist of spots and blotches or sometimes
of irregular scrawls, variously distributed, and intermingled with the usual underlying marks of
olive-gray. Measurements of 69 examples average 53.5 x 38.5, those showing the four extremes
measuring 62 x 37, 52 x 42, 48.5 x 37, and 52 x 30.5 mm. (Bent, 1921, 158).
Distribution: Breeds from the Caribbean coast of Central America and the Lesser Antilles
northward to southern California and Maine; recorded in summer from the coast of Venezuela and
the islands of Curacao, Aruba, and Bonaire; winters from the South Atlantic and Gulf coasts of
the United States to Brazil and northern Peru.
On the Atlantic coast of South America the Laughing Gull moves southward
through the warm littoral waters at least as far as the mouth of the Amazon.
According to Léotaud (1866, 533), who calls the species Larus ridibundus, the
name of the European Brown-headed Gull, it is common at Trinidad between
July and October. Cherrie (1916, 374) found it to be a conspicuous species at
certain seasons in the Gulf of Paria and about the various mouths of the Orinoco.
It is well known in the Guianas, and Snethlage (1914, 81) records three winter
specimens from Marajé Island. The vicinity of Para apparently marks the
southeastern limit of the range on this coast of South America (Goeldi, 1894,
585).
Along the Pacific coast, the Laughing Gull is one of the birds which serve
as more or less of an index to the temperature, and perhaps to other physical
attributes, of the coastal water. Its range terminates short of the region in
which cool upwelling becomes pronounced, and occasional southward inroads
of the species down the coast of Peru appear always to synchronize with periods
in which the ordinary Humboldt Current phenomena have been pushed back
or obscured by a strong development of the warm current known as El Nifio.
Other conspicuous species with which the Laughing Gulls become associated
at such times include the Royal Tern, Caribbean Man-o’-war Bird, Masked
Booby, and Red-billed Tropic-bird.
No doubt the Laughing Gull is a common resident during the northern-
hemisphere winter along the shores between Panama and the Gulf of Guayaquil.
To southward of the latter point it appears only sporadically, under the special
LAUGHING GULL 1073
conditions noted above. On January 24, 1925, I saw a number of the birds on
bars inside the mouth of the Chira River, just north of latitude 5° S. At this
time E] Nifio was running southward with extraordinary force, and both the
meteorological and the oceanographic régime were of a sort unprecedented
during the preceding 30 years or longer. Under such circumstances the Laugh-
ing Gulls might well wander farther southward, but there seems to be no
justification for the often repeated statement that its winter range extends to
Chile.
I judge from hearsay accounts that this is the species of gull which at times
comes up from the sea in flocks to the neighborhood of Guayaquil, in order to
feast upon the recurring plagues of crickets. Between January and March, 1925,
Laughing Gulls were common along the lower stretches of the Guayas River,
in Ecuador, as well as on the outer coast near Point Santa Elena. On February
14 I saw many standing on current-borne flotsam from the north in Santa Elena
Bay, close to the small bare island called Pelado. Examples in winter plumage
and in worn post-juvenal plumage were collected at this time and place by Mr.
Heilner and myself. During the Brewster-Sanford Expedition the species was
not encountered until Mr. Beck neared the end of his long voyage, when he
collected a series of adults in process of change from black-hooded to winter
plumage at islets near St. Thomas, West Indies, during August and September,
1916.
Dwight (1925, 266) points out that the alleged differences between the
resident Antillean Laughing Gulls and those of the North American continental
coast are too slight and inconstant to warrant the taxonomic recognition which
has been proposed for them. It seems still to be questionable whether the
Laughing Gull belongs to the actual breeding avifauna of South America. At
Margarita Island and adjacent parts of the Venezuelan mainland, it has been
found between March and July as well as during the winter season, as recorded
by Cory (1909, 233) and previous observers cited by him. So far as I can learn,
however, nests and eggs are unknown from any part of this Leeward Island
chain. In any event, the breeding range approaches as close to the continent as
the island of Grenada, where the habits of the Laughing Gull have been studied
by Wells (1902, 239), from whose report the following account is abridged.
At Carriacou the Laughing Gull or ‘‘Mauve"’ is plentiful throughout the
year. Large flocks are to be seen sitting upon the water, keeping an eye upon
the movements of pelicans. The gulls seldom fail to demand a share of each
pelican’s catch, literally taking food from the mouth of the larger bird, all the
while uttering their laughing cry which, according to the local fishermen, is
“half-half-half.””
The breeding season, which is practically the same here as on the coast of
Massachusetts, comes during the months of May and June, when the gulls can
be found nesting on the small islets, of which one known as Ile-de-Large is the
favorite. The three or four eggs are laid in little depressions among tufts of
grass or bare rocks, the sites being so close together that one has difficulty in
walking without treading upon the eggs. The period of incubation is about
1074 OCEANIC BIRDS OF SOUTH AMERICA
20 days and, after the hatching of the young, the parents noisily depart at a
very early hour of the morning for their feeding grounds, which are chiefly off
the western coasts of the various islands. Between four o'clock in the afternoon
and dusk, they are uninterruptedly returning, laughing and calling to each
other as they make their way across the water.
These gulls apparently do not dive, but depend for such food as they capture
themselves upon the shoals of fry and small species of fishes that come to the
surface. They have been known, however, to bite at the backs of fish far too
large for them to capture. When heavy rainfall covers the island pastures with
numerous pools and puddles, the Laughing Gulls resort to these in order to
feed upon earthworms which issue at such times from the ground.
GRAY-HOODED GULL
Larus cirrocephalus cirrocephalus
Larus cirrocephalus Vieillot, 1818, Nouv. Dict. Hist. Nat., 21, p. 502 (Brazil).
Names: ‘‘Gaviota de Capucho Gris.’” Synonyms of the specific name include poliocephalus,
plumbiceps, major, minor, and polionotus. The species has frequently been reported upon under the
name maculipennis. This gull is also a bird of the African continent, and various other specific names
have been used for the branch of the population now recognized as a distinct subspecies.
Characters: The pale gray hood, which darkens toward the posterior margin, the pattern of
white subapical spots on the two outer primaries, and tongues of white with more or less square
ends on the median primaries, are diagnostic of this gull.
Adults in breeding plumage (sexes alike): Hooded head very pale gray, almost white on fore-
head and chin and darker all around toward the caudad margin; mantle light neutral gray or
darker with a faint purplish tinge; primaries brownish black, with white subapical mirrors on the
two outer quills and small] apical spots on all the others; these quills basally white, which hardly
shows on the two outermost; the more proximal] primaries show more or less square-ended white
areas on the outer webs, and gray tongues of increasing size on the inner webs; secondaries, tertials,
and coverts gray; primary coverts, alula, and small adjacent coverts white; wing-lining gray like
the mantle; tail white, sometimes dusky on the shafts or even on the webs; ventral surface white,
with a rosy bloom. Iris napthalene yellow; eyelids, tarsus, and toes dragon’s-blood red; bill
madder brown, becoming diamine brown at base; claws black (flesh colors from Wetmore, 1926,
136). Beck's labels describe the bill as ‘‘dark crimson.”’
In winter adults the flesh colors are duller, and the head is white with a pale gray occipital
area or half hood, and a dark auricular spot and eye-crescent; anterior half of eye-ring white;
hind neck gray, slightly paler than the back, the feathers being white basally and narrowly
edged.
12 males: wing, 308-338 (325); tail, 121-133 (127.7); exposed culmen, 38-42 (40.3); tarsus,
50-60 (54.7); middle toe without claw, 35-43 (40.2) mm.
10 females: wing, 305-323 (314.9); tail, 120-134 (127.7); exposed culmen, 35-41 (37.4); tarsus,
» 48-54 (51); middle toe without claw, 34-42 (7.2) mm. (Dwight, 1925, 271).
Younger birds resemble adults except that the back is usually browner, the feathers showing
faint brownish edgings, and the sides of the throat are usually buffy; an imperfect gray hood is
assumed in first nuptial plumage.
In juvenal plumage the mantle is wood-brown or pale snuff, with rather narrow paler edgings,
passing into neutral gray on the rump; upper tail coverts grayish white, the basal parts of the
feathers being entirely gray; head brownish mouse-gray, the color extending to below the eye,
with darker auriculars; hind neck with an ill-defined grayish white collar; forehead, lores, and a
large post-ocular spot lighter; ventral surface white, tinged with brown on the sides of the breast;
wing quills generally grayer, and the coverts much more brown than in adults; tail white, with a
GRAY-HOODED GULL 1075
band of brownish black 20-25 mm. in width, succeeded by narrow whitish tipping; this tail band
is widest on the central rectrices, reducing outward. Iris brown; bill, legs and feet dull yellow.
Examples in natal down are buffy on the dorsal surface, marbled with white and spotted with
pale clove-brown, the head being generally whiter and with darker spotting. The ventral surface
is paler, especially on the breast, obscurely spotted, and with a dingy band across the throat.
Eggs of the South American subspecies are perhaps unknown.
Distribution: Breeds from southern Brazil to the Province of Buenos Aires, and ranges up the
Parana and Paraguay Rivers to Paraguay and Matto Grosso, perhaps only casually reaching the
Pacific coast in central and northern Peru.
This extraordinarily interesting gull occurs on the continents of both South
America and Africa, its breeding range in the latter being confined chiefly to
the central region of equatorial lakes. Most students have been unable to
recognize even subspecific differences between birds from opposite sides of the
South Atlantic. Saunders (1896, 199) saw reasons for believing that the species
had crossed from Africa to America during comparatively recent times, and its
somewhat peculiar distribution in the New World appeared to him to be more
extraordinary than its hurdling of the oceanic barrier. Recently, Wetmore
(1926, 135) expressed himself as unable to recognize appreciable differences
between the South American and African birds, but Dwight (1925, 275) has
shown that there are three distinct though overlapping characters which dis-
tinguish Old-World and New-World races. In a study of 50 specimens, he found
that African examples are definitely darker in the shade of the mantle, and that
South American birds are slightly larger and have decidedly more extensive
mirrors on their wing quills.
As regards distribution in South America, great caution must be used in
accepting or interpreting published information because of the frequency with
which the Gray-hooded Gull has been confused with other species, particularly
with Larus maculipennis. Dwight states that cérrocephalus breeds in the river-
marshes and on some of the lakes of Argentina, Paraguay, and southern Brazil,
and that in the non-breeding season it ranges along the southeastern coast of
Brazil as well as the coasts of Argentina, Chile, and Peru. He adds that the
birds probably reach the Pacific side of the continent by way of the Strait of
Magellan. Hellmayr (1932, 412), however, has been unable to accept any
report of the occurrence of this species in Chile, and has shown that records
under its name refer in reality to Larus maculipennis. Furthermore, the few
records from the coast of Peru, such as that of MacFarlane (1887, 208) of an
example taken off Paita in July, and those of Saunders (1896, 200) of specimens
from Callao and Paita collected during December and January, refer, as will be |
seen, to captures during the height of the breeding season no less than during
the southern-hemisphere winter. Without implying a questioning of the
identification, it would be well for some ornithologist to reéxamine in the
British Museum the skins and labels upon which the Peruvian records are based.
Finally, with reference to the general account of breeding habits given by
Dwight, it is of interest to note Gibson's (1920, 82) comment that the South
American nesting grounds of the Gray-hooded Gull are still unknown. The
only first-hand description of its breeding I have been able to find is an unsatis-
1076 OCEANIC BIRDS OF SOUTH AMERICA
factory one by Venturi, who states that during the month of November, 1926,
he found many nests and eggs of both Larus cirrocephalus and L. maculipennis
in the great marshes near Bahia Blanca, Argentina (Hartert and Venturi,
1909, 254).
At any rate, observers agree that in the lands about the Rio de la Plata the
Gray-hooded and Brown-hooded Gulls consort closely, even if they do not
actually mingle, during the months of the year that come between the breeding
seasons. Curiously, the Gray-hooded species was nowhere encountered by
Beck during the course of the Brewster-Sanford Expedition, nor does it seem
to have been collected by members of any other American Museum party in
South America. Our only specimens, obtained in exchange, were taken at the
Estancia los Yngleses, near Lavalle, Buenos Aires, during April, 1909. At this
same locality Wetmore became acquainted with the birds during November,
1920.
Owing to the frequent confusion of the Gray-hooded and Brown-hooded
Gulls, the following summary of their distinctive characteristics, as drawn from
the observations of Dwight, Wetmore, Gibson, Friedmann (1927, 164), Durn-
ford (1877, 201), and Aplin (1894, 211), may be of interest:
Larus cirrocephalus— Larus maculipennis—
Hood dark brown in summer; head white
with dusky auriculars and eye-crescent in
winter.
Iris brown.
Primaries largely white-tipped, or with much
Hood pale gray (lighter in winter), darken-
ing at the posterior margin.
Iris yellow.
Primaries with never more than small sub-
terminal white spots on the two outer
quills.
Call rather long drawn out, a strange caw-
caw similar to that of a crow and quite
ungull-like.
Flight steady and direct, with rapid wing-
strokes.
more extensive spots, except in first-year
plumage.
Notes sharp, staccato, and vehement.
Wing-strokes slow and deliberate, suggesting
those of Franklin's Gull.
Wetmore found that the Gray-hooded Gull, like the other Argentine species,
frequents the vicinity of the slaughtering pens in search of waste scraps of meat.
Durnford gives us the following account of the species as he observed it to
northward of the city of Buenos Aires between the months of March and July:
Unlike Larus maculipennis, it never wanders inland, but frequents the shallow shores of the La
Plata, feeding on dead fish or offal, and flocking round the fishermen when they are hauling their
nets to get a share of the spoil. Asa rule, this species does not mix with Larus maculipennis, though
now and then they are seen together; but all the flocks or parties I have observed when flying
from one spot to another have always been composed of birds of its own kind. Adults, after once
attaining their pearl-grey hood, never lose it, though in winter it becomes rather lighter, and
those with white heads are immature birds, which do not attain their full plumage till after their
second moult. I have seen many birds throughout May and June of the present year with well-
defined dark grey hoods. Some specimens, when first killed, have a delicate faint pink tinge on
their underparts, also observed in L. maculipennis, which, however, quickly fades after death.
The colour of the iris varies a good deal in different examples, being pale grey, grey with a tinge
of yellow, and grey with a tinge of light wood-brown. This is probably attributable to age.
MOUNTAIN GULL 1077
MOUNTAIN GULL
Larus serranus
Larus serranus Tschudi, 1844, Wiegm. Arch. fiir. Naturg., 10, pt. 1, p. 314 (Peru = Puna region of Junin).
Names: Andean Gull, Tschudi’s Gull. In Peru the species is known as the ‘‘Serranita’’;
recorded names in Chile are “‘Chelli’’ and ‘‘Quiulla.’’ A synonym of the specific name is per-
sonatus, besides which cirrocephalus, glaucotes, and bonapartii have been used through confusion with
other species.
Characters: Larger than other dark-hooded gulls confined to South America, and distinguish-
able from the Laughing Gull by its mantle of much paler gray.
Adults in breeding plumage (sexes alike): A complete hood of brownish black; mantle pallid
neutral gray; primaries black, with large mirrors on the outer three and white stripes or tongues
along the shafts of all; small apical spots, beginning usually on the second or third from the
outermost, increase in size inwards; primary coverts and adjacent small coverts mostly white;
secondaries and lesser coverts gray; wing-lining gray, with the edge and the axillars white; alula
dusky, with white on the outer webs of the feathers, these and the adjacent coverts forming a
large wing-patch; tail white; ventral surface white with a rosy tint. Iris brown; bill, legs and
feet dark reddish.
In winter plumage the head and neck are pure white, which blends into the gray of the back; a
black eye-crescent nearly surrounds the broad white eye-ring, which is narrowly black at its junc-
tion with the eyelid.
15 males: wing, 348-370 (363); tail, 140-158 (150.2); exposed culmen, 37-42 (39); tarsus,
54-61 (56.6); middle toe without claw, 39-43 (41.1) mm.
7 females: wing, 336-358 (349.7); tail, 138-149 (144.3); exposed culmen, 33-37 (35.4); tarsus,
51-54 (53.1); middle toe without claw, 37-40 (38.4) mm. (Dwight, 1925, 277).
In juvenal plumage the mantle is wood-brown, with whitish feather edgings, mixed with
much pale gray of the exposed basal parts of the feathers; rump gray, paling to white on upper
tail coverts; head grayish wood-brown, paler on the crown, the forehead, lores, a broad eye-ring,
post-ocular stripe, and cervical collar grayish white; large eye-crescent and margin of eye-ring
black; auriculars deep brown; hind neck paler than the back, the feathers merely tipped with dark
wood-brown; ventral surface white, the throat, breast, and flanks faintly washed with wood-
brown; the wings are similar to the adult stage, except that the white mirrors and tongues are
smaller and narrower, and the gray secondaries and lesser coverts more dusky and brown, respec-
tively; the tail is chiefly white, with a subterminal band of brownish black, 20-30 mm. in breadth,
which diminishes to a shaft-line or a smudge on the next to the outermost rectrices, the outer pair
being white; the tips of the central rectrices are pale wood-brown, which becomes lighter on
successive feathers outward. Bill and feet blackish.
The natal down is undescribed. At Lake Junin, Peru, on March 13, Beck collected a fledgling
with traces of down still clinging to the juvenal plumage.
The eggs are apparently unknown.
Distribution: Breeds about high Andean lakes, from Ecuador to northern Chile and north-
western Argentina; descends sporadically to salt water along the coast of Peru.
The ‘‘Serranita’’ is essentially an inland gull, belonging to the high plateaus
of the Andes, where the greater part of the population apparently remains
throughout the year. According to Dwight (1925, 279), the species is a member
of a widely distributed group of continental and river gulls having representa-
tives in South America, Africa, India, and Australia. These comprise the sub-
genus Cirrhocephala, birds which vary as regards the presence or absence of a
dark hood, but resemble each other closely in the shape of the bill, the pattern
of the wing markings, and other fundamental characters.
Great uncertainty seems to be current regarding the place of this species as
1078 OCEANIC BIRDS OF SOUTH AMERICA
an oceanic bird. It is said by many authorities, including Peters (1934, 322), to
descend from the mountains to the coast of Peru during the non-breeding period.
Others, such as Dwight and Alexander (1928, 135), credit it with occurring
likewise along the coasts of Ecuador and Chile. I can, however, discover
nothing to substantiate its presence at sea level in Ecuador, while Hellmayr
(1932, 411) finds that it has not yet been found anywhere near the ocean in
Chile. Furthermore, it appears that a large proportion of the published records
from the Peruvian coast are based upon sight identification, while even these
are by no means confined to the season of southern winter. Finally, Mr. Beck's
collections show that the species is abundant at its lofty mountain breeding
grounds during the midwinter period, thus proving that there is no regular or
general migration to lower levels at this season.
We have two coastal specimens, one of which I shot at Paracas Bay on
November 10, 1919. This was a female, the only one of its kind seen; its stomach
was empty except for a few feathers which were probably its own. The second
coastal specimen, taken by Beck at Ancén on May 8, 1913, was an adult male
still in full winter plumage, with a nearly all-white head, a black anterior eye-
crescent, and a dark spot well behind the eye. Additional examples taken at or
near Callao and Islay, Peru, during the months of September and October, are
recorded by Saunders (1896, 190). MacFarlane (1887, 204) states that the
species was common in Callao Bay during both April and August, 1883, though
he seems not to have confirmed his identification by the collection of specimens.
A small flock flying offshore at evening was observed by Beck near Salaverry,
January 5, 1913. Sight records of my own include a number over the ocean off-
shore from Asia Island, December 5, 1919; several hundred filing southward
against the coastal mountains above Mollendo on December 19, 1924; and a
number of black-headed adults resting on the water off Point Parifias, in north-
ern Peru, on January 21, 1925. In these several instances I was satisfied as to
the identity of the species, but it should be borne in mind that along the coast
of Peru the presence of migrant Franklin's Gulls and Laughing Gulls, in addi-
tion to the native coastal species, tend to make sight identification unsatis-
factory except when the birds can be observed at close range and in company
with other species suitable for comparison. At Pisco, in February, 1935, Dr. Chapin
saw several Mountain Gulls under good conditions for positive determination.
During Beck’s several periods of mountain field work in Peru, he collected
excellent series of the Andean Gull at Lake Junin between March 13 and 31,
1913, and at Lake Titicaca between the last week of July and the third of August
of the same year. One of the March birds is a fledgling with considerable down
still clinging to the tips of its plumage. All of the adults had, of course, long
passed their breeding state, but the nuptial plumage, with the black hood and
new wing and tail quills, is represented by August specimens from Lake Titicaca
(altitude 3840 meters). In the Museum collection there are also specimens in
breeding plumage from Antisana, Ecuador, and from the highlands of Bolivia,
all taken during June and July. Apparently the breeding season begins in
October or November.
FRANKLIN'S GULL 1079
FRANKLIN’S GULL
Larus pipixcan
Larus Pipixcan Wagler, 1831, Isis, von Oken, col. 515 (Mexico).
Names: Called in Peru ‘*‘Pardela,’’ a word applied also to other species of sea birds; “*Cagiiil’’
in Chile. Synonyms of the specific name include franklini, cucullatus, kitlitzsi, and cinereo-caudatus,
besides which accounts of the species have been published under the names of such other gulls as
L. serranus and L. atricilla.
Characters: Mantle darker than in any other American dark-hooded gull except the Laughing
Gull, from which it may be distinguished by its smaller size and the white tips to the outer pri-
maries. The very dark half-hood of the winter plumage is also diagnostic, since it is unlike that of
any other species except certain much larger gulls, such as Larus belchers.
Adults in breeding plumage (sexes alike): Head with complete deep black hood; a broad eye-
ring, white posteriorly, divided by a black line, the anterior quadrant being black like the hood;
mantle deep neutral gray, paler than in L. atricilla; ventral surface white, tinted with a rosy hue
except on the throat along the margin of the hood; primaries white, with broad black bands on
the five outer quills, the outermost having also a black outer web; apical white areas large, the
whole tip of the outermost primary being white for 15 mm.; these quills are basally deep gray,
paling to white on the inner webs and terminally; tail white, the central quills basally grayish.
Iris brown; bill maroon, with a blackish bar or spot toward the tip, which is dragon's-blood red;
gape crimson; legs and feet bay or burnt sienna.
In winter plumage a dull black half-hood, with white-edged feathers, extends from forehead
and crown to the level of the eye; remainder of head white; hues of bill and feet duller than in
summer.
14 males: wing, 263-286 (277.2); tail, 98-111 (103.9); exposed culmen, 29-34 (30.7); tarsus,
41-45 (42.5); middle toe without claw, 30-33 (31.5) mm.
12 females: wing, 262-283 (273.2); tail, 97-107 (100.7); exposed culmen, 27-33 (29.2); tarsus,
39-44 (41.4); middle toe without claw, 30-35 (31.1) mm. (Dwight, 1925, 289).
In younger stages and juvenal plumage the mantle is grayish sepia-brown, with narrow buffy
edgings on the feathers, which are basally grayish white, deepening to the subterminal dusky
brown area; the rump is neutral gray, paling toward white on the upper tail coverts, which nearly
conceal the gray of the rectrices; head and nape darker than the back, with a dusky half-hood
which includes the crown, occiput, upper neck, and sides of head; auriculars more dusky; forehead,
lores, and a broad interrupted eye-ring, which includes only the posterior half of the eye, rather
dingy white, eye-crescent brownish black; nape white, washed with pale gray; ventral surface
white, with a slight buffy or dusky clouding at the sides of the throat; primaries dull black, with
small white apical spots, increasing in size inward, the inner webs of these quills paling toward
gray; tail pale neutral gray, with a subterminal black band 15-25 mm. in breadth, and a narrow
buffy or grayish white terminal edge, the outer rectrices being usually white, with only a shaft
streak or a dusky spot. Bill olive-drab, blackish toward the tip; legs and feet olive-drab.
Since this species does not breed in South America, descriptions of the natal down and eggs
are omitted.
Distribution: Breeds in the interior of western North America, east of the Rocky Mountains,
and migrates southward to winter in the Gulf of Mexico and along the west coast of South America
between Ecuador and the middle part of the Chilean coast.
Franklin's Gull is a northern-hemisphere winter resident along the entire
desert stretch of the west ccast of South America, between the Gulf of Guaya-
quil, where I observed a large flock on December 6, 1924, and the south-central
part of the coast of Chile. As noted by Hellmayr (1932, 411), the species has
been taken at Mocha Island, which seems to be the southern outpost of its
known range. It has been found abundantly at the Galapagos Islands during
1080 OCEANIC BIRDS OF SOUTH AMERICA
February and March (Gifford, 1913, 42). Between the latter part of October
and the middle of May, one is likely to see from shipboard, at almost any point
along the steep and arid coast of Peru, enormous flocks made up mostly of gulls
of this species, though sometimes mixed with such birds as Larus modestus,
belcheri, and dominicanus. The Franklin's Gulls, however, are much more given
to mounting into higher regions of the atmosphere than are any of the native
species.
In our northern autumn 7.e. the southern-hemisphere spring, Franklin's Gull
becomes common in northern Peru at a time when few or none are yet to be
found along the southern shores of the republic. In 1918 I saw them appear
suddenly in the Bay of Callao, during the first week in November; but the south-
ward migration must, on occasion, be very much earlier, for Hellmayr has
cited a number of September records for central Chile. Nicoll (1904, 50) found
them abundant in the harbor of Valparaiso during the middle part of February.
West coast dates late enough to be of interest are as follows: Valparaiso,
March 16 (Beck); Callao Bay, common throughout April (MacFarlane, 1887,
204); Ancén, Peru, May 12 (Beck). It is, of course, to be expected that non-
breeding examples may remain south of the equator throughout the year.
The small size and the wing-pattern (very like that of ichthyaetus) distinguish this gull in all
plumages, and when adult the two central tail feathers are gray basally unlike any other species.
The very dark half-hood of the winter plumage is a good deal like that of belcheri and is different
from the gray partial hoods of any of the other species. The juvenal plumage might be mistaken
for that of africilla but the latter is uniformly browner especially about the head and does not
have the white of pzpixcan that contrasts with the half-hood. The tail-band too is very much
narrower and does not reach the outer rectrix, and the primaries are white-tipped.
The complete moult occurring at the prenuptial season is a feature unknown in other gulls,
but the evidence of its occurrence is conclusive. It may perhaps be linked with the origin of the
species, as pipixcan is the only species that regularly breeds in the Northern Hemisphere and then
migrates to south of the equator.
If we suppose that, like maculipennis, it nested and moulted at one time only south of the
equator and, as it extended its range, climatic conditions necessitated a change in the breeding
season, why does it not breed south today? And why the double complete moult? It is a matter
for speculation and the case of pipixcan is unique among the gulls. If the colonies had breeding
peaks at widely different times of the year, it would be easy to explain the moult but no evidence
has been produced to show that the species breeds anywhere except at the northern fringe of its
range and only during the months of July and August (Dwight, 1925, 292).
The American Museum Collection contains Franklin's Gulls taken at Chor-
rillos and Ancén, Peru, between February and May, 1913; a series from Val-
paraiso taken during March, 1914, and seven adults from Pacasmayo collected
on January 3, 1920. Many of Beck's Valparaiso specimens still show the rich
pink suffusion on the white feathers of the breast. These birds are in winter
plumage, but a female shot at Ancén, Peru, on April 24, is in full breeding
plumage and the eggs in the ovary were distinctly enlarged. It is also of interest
that I saw a black-hooded bird, still in full breeding plumage, as late as Decem-
ber 4, 1919. This was at Asia Island, Peru, when the gull flew low over a cor-
morant colony. I have no evidence, however, that Franklin’s Gulls are inter-
ested in egg-stealing, as their larger relatives are.
FRANKLIN'S GULL 1081
Toward evening, when the sun over the western ocean peeps below the pre-
vailing blanket of cloud that extends offshore from middle heights of the
Peruvian coastal ranges, the yellow rays will sometimes illumine the breasts
of thousands of Franklin's Gulls moving northward or southward, well behind
the shore, against the lofty, plantless slopes. The notes of Mr. Jaques state
that while he was on shipboard and at anchor in the harbor of Salaverry, a
blast of the steamer’s whistle about four o'clock in the afternoon startled
several thousand Franklin's Gulls into concerted flight. The birds congregated
into a dense flock, then circled to a great height above the water, and finally
formed into long lines and moved eastward toward the mountains. In the
roadstead of Huarmey I saw a flock of these birds feeding at evening and filling
the air, like a swarm of gleaming midges, along a line fully 314 kilometers in
length. The body of birds as a whole was facing up-wind, and those in the rear
of the column were continuously flying forward over the van, to descend again
to the surface of the water and so maintain contact with the shoal of anchovies
that was the center of their united interest. Perhaps these gulls are most active
in early morning and at evening, for during the middle part of the day I fre-
quently saw them standing in droves on sandy shores, sometimes with one
dainty foot lifted from the ground and with the bill tucked among the feathers
of the back. The sandy beaches of Lobos de Tierra Island were favorite resting
places for large numbers, in December, 1920, and in the same month I saw more
than a thousand standing along the edge of a white bar on the mainland coast,
north of Pacasmayo, with their pink breasts perfectly reflected in a shallow
pool. A passing Indian informed me that the name of the bird was ‘‘Pardela,”’
the same term by which I had already heard it called at Pisco.
Jaques observed numbers of Franklin’s Gulls not only in the harbor of Callao,
but also in the cultivated fields of the lower Rimac valley in February. During
his visit to Ancén in the same month, Franklin's Gulls vastly exceeded the
Gray Gulls (modestus) in numbers. The Gray Gulls, however, were hunting
actively along the wash of the waves, whereas Franklin’s Gulls were resting on
the beach, but never feeding there. The presence of Franklin’s Gulls in the
rich irrigated fields between Callao and Lima shows that, although they live
mostly upon fishes and crustaceans during their winter sojourn, they do not
entirely forget the insect-eating proclivities which make them the ‘‘Prairie
Pigeons’’ of North America.
Stomachs of eight specimens shot on the beach near Pacasmayo, January 3,
1920, at about eleven o'clock in the morning, varied between being practically
empty and about half-filled with food. The one with the greatest quantity
held about 300 small crustaceans, representing the megalops stage of a crab,
together with an equal amount of bones of the fishes known as silversides or
pejerreyes (Atherinidae), and finally, a tiny fragment of an alga. The other
seven stomachs contained gravel or fragments of Bryozoans, probably taken as
gravel rather than as food, as well as bits of barnacle (Balanus), fish bones,
fragments of a mollusk, and a few feathers. All but two specimens showed
traces of fishes, which seemed to be either silversides or anchovies.
1082 OCEANIC BIRDS OF SOUTH AMERICA
BROWN-HOODED GULL
Larus maculipennis
Larus maculipennis Lichtenstein, 1823, Verzeichn. Doubl., 2, p. 83 (Montevideo, Uruguay).
Names: Spot-winged, Pink-breasted, Pink-bellied, or Black-headed Gull; ‘‘Gaviotina,"’
“Gaviota de Capucho Café,’’ ‘‘Gaviota de Cabeza Parda’’; ‘‘Cagiiil’’ at Chiloé Island. The most
important synonyms of the specific name are glaucodes or glaucotes; the bird has also been described as
albipennis and roseiventris, besides which it has been confused in the literature with Larus ridibundus,
the Brown-headed Gull of Europe, with L. serranus, and more particularly with L. cérrocephalus,
a South American Gray-headed Gull of about the same size and of overlapping range.
Characters: Distinguishable from Larus cirrocephalus, the only South American gull of partly
similar range, by its dark brown hood and pale gray under wing coverts; and from all other gulls
of similar size by the wholly white-tipped outer primaries of the fully adult stage.
Adults in breeding plumage (sexes alike): Hood deep brown, darkest at its junction with the
neck, and interrupted by a broad white horseshoe-shaped eye-ring around the posterior two-thirds
of the lids; mantle gray; ventral surface white, with a rosy tinge; primaries white (tipped or
spotted with black on the inner webs only in not quite mature plumage, or in younger stages);
the subsequent condition is somewhat variable, the two outer quills usually having very long white
tips, the median occasionally showing small spots of black, the inner four or five being almost
wholly gray; the outer web of the outermost is always black basally; the rest may or may not have
a dash of black, while succeeding feathers inward are white on the outer web, until replaced by
the almost entirely deep gray quills of the inner series; secondaries and tertials gray, like rest of
mantle; alula, axillars, edge of wing, and adjacent coverts white; under wing coverts pale gray;
tail white. Iris brown; margin of eyelids dull Brazil red; bill, tarsus and toes Vandyke red; claws
dull black (flesh colors from Wetmore, 1926, 133).
In winter plumage the head is white, with a slight gray clouding on the occiput, the nape
somewhat grayer where it blends with the back. Bill and feet duller than in summer.
11 males: wing, 280-310 (292.1); tail, 113-127 (120); exposed culmen, 34-39 (36); tarsus,
45-51 (46.4); middle toe without claw, 34-37 (35.3) mm.
7 females: wing, 271-292 (284.6); tail, 111-119 (114.9); exposed culmen, 32-37 (33.6); tarsus,
44-46 (45); middle toe without claw, 33-35 (34.1) mm. (Dwight, 1925, 296).
In younger birds the black subterminal markings curve across the tip of the wing in half or full
bars, such marks being lost progressively with age from the outer quills inward. A nearly or quite
terminal tail band, which involves all but the outermost rectrices, is worn until the moult of the
first-year plumage.
In juvenal plumage the mantle is bister-brown, with snuff-brown or paler feather edgings;
crown and auriculars drab or dusky snuff-brown, with indistinct paler edgings; eye-crescent black;
rest of head white; hind neck brown like the back, from which it is separated by a whitish collar;
ventral surface white, the sides of neck, throat, breast, and flanks tinged with buff, which some-
times crosses the breast; primaries black, white-tipped and with elongate mirrors of variable size
on the outer two, which have little or no white at the base; succeeding primaries, however,
usually have the outer web grayish white nearly to the tip, but terminally restricted more or less
to the shaft by a black edging beginning about halfway between the ends of the primary coverts
and the tip; inner primaries decidedly grayer, with black subterminal bands and pale gray apical
spots; primary coverts and alula white, occasionally_with dusky edgings; secondaries brownish
black or clove-brown, with broad gray margins and tips; tertials similar, but the inner feathers
with brown edgings like the back; greater coverts clear gray, as in adult plumage, but faintly
brownish at the tips; median coverts gray basally, with rather narrow snuff-brown terminal areas,
edged with paler brown; lesser coverts brown, like the back, the marginals gray; edge of wings and
axillars white, and wing-lining grayish white; tail white with a rather narrow dull black or
brownish subterminal band, which is widest on the central rectrices, reducing outward and often
absent from the outer pair of quills. Bill brownish, with a blackish tip; legs and feet brownish
flesh color.
BROWN-HOODED GULL 1083
In natal down the dorsal surface is rich buff, heavily marked with black lines or spots, which
are clearest on the head; the ventral surface is paler buff and unmarked. Bill, legs, and teet yellow-
ish brown.
Saunders (1891, 373) notes that the eggs of this species are similar in character to those of other
marsh-breeding brown-hooded gulls in other parts of the world. Examples collected by Beck at
East Island of the Falklands, December 10, 1915, vary in ground color from pale olive greenish to a
buffy or café 2u lait hue. Their brown markings include spots, blotches, and vermiform splashes,
some of those on the surface being very dark and those within the texture of the shell pale. Most
of the eggs are rather uniformly marked, with only a slight tendency toward heightened pigmen-
tation near the larger end. In size and shape, however, they are considerably more variable
than in color and markings. In one set of three, the ground color of one is quite different from
that of the other two. In the other four instances, the eggs in the respective sets look more
like pairs or trios. Five sets measure as follows: 54.1 x 41.2, 52.7 x 39.5, 52.7 x 38.2; 53.1x 38.9,
54.5 x 38.3, 55.8 x 37.8; 54.6 x 38.4, 57.7 x 38, 57.5 x 38; 53.2 x 38.6, 54.8 x 38.9; 48.6 x 37,
48.6 x 36.3 mm.
The nesting season is apparently similar throughout the range. Germain (1860, 314) writes
that the Brown-hooded Gulls congregate at Chiloé Island for breeding in late November.
Distribution: Breeds in southern South America, from islets along the coast of eastern Uruguay
and from the vicinity of Valdivia, Chile, southward to the Falkland Islands and Tierra del Fuego;
ranges northward to Alagoas, Brazil (latitude 10° S.), and to Tarapaca, Chile (latitude 20° S.).
The alleged presence of the species along the Peruvian coast requires verification.
The literature relating to the Brown-hooded Gull of southern South America
is for two reasons difficult to interpret. In the first place, the name and identity
of this bird have been confused with those of a Gray-hooded Gull (Larus cirro-
cephalus) of about the same size. Although the range of the latter is somewhat
more northerly, the two species overlap in lands around the Rio de la Plata.
Furthermore, the progressive change in wing-pattern as Brown-hooded Gulls
advance toward maturity has led many ornithologists to the conclusion that
birds with “‘spot-wings’’ and those with ‘‘white-wings’’ represent two species
which have, indeed, long passed current under the respective names maculipennis
and glaucodes. The large series of specimens obtained during the Brewster-
Sanford Expedition has fortunately enabled Dwight (1925, 298) to determine
that differences in primary markings are due entirely to age and individual
. development. There is but one species of Brown-hooded Gull in South America,
of which the fully adult bird represents the “glaucodes’’ type, while a retarded
or reversionary second-year plumage represents the ‘‘maculipennis’’ type. Since
the latter name has priority, it must be accepted as that of the species.
The American Museum possesses specimens of this gull from Rio Grande do
Sul, Brazil, and the Province of San Juan, Argentina, taken in July, and both
young and adults collected in Cautin, Chile, during the months of January,
February, September, and December. In addition to these, Mr. Beck obtained
a large series, as follows: ‘
Chile: Valparaiso, March; Corral, September and October; Ancid and
neighboring parts of Chiloé, April and May; Magallanes and other parts of the
Strait of Magellan, February.
Argentina: Ushuaia, July; Rio Gallegos, August; Rio Santa Cruz, May;
Mar del Plata, September and October.
Falkland Islands: November.
1084 OCEANIC BIRDS OF SOUTH AMERICA
At the Falklands he also collected eggs and fledglings, while other youthful
stages are represented by specimens from Magallanes and elsewhere.
This is the species which Cordova found in the Strait of Magellan, and which
is thus quaintly described in the English translation of his book (1820, 81):
The sea-gulls also are here in prodigious numbers, and of many different sorts. The most
beautiful is one not bigger than a large turtle; its head is black, the whole body and wings of a
dazzling whiteness, mixed with a few light black strokes; diamonds and rubies themselves do not
equal the brilliancy of its eyes, round the pupils of which is a circle coloured like carmine, which
adds infinitely to the beauty of this animal.
Dwight has fully described the moult and the plumage vagaries of this gull,
which had puzzled many earlier students. “‘Laggards’’ in moult tend to give
the population a heterogeneous appearance. Thus three adult females taken by
Beck at Ushuaia on July 19, 1915, represent three completely different stages,
one being brown-headed, one in full winter plumage, and the third exactly
intermediate, with a mottled head and a white forehead and chin. During
August and September the normal assumption of breeding dress takes place,
with a corresponding heightening in the carmine of the eyelids. Examples
collected by Beck in the Falklands on November 4, 1915, still show the pink
breasts clearly. According to Cobb (1933, 33), this suffusion is hardly noticeable
under the summer sun, but on calm bright days of winter it is extraordinarily
conspicuous, the rosy hue being reflected from still waters as brilliantly as it
shows through the air.
This Patagonian gull is so closely related to the Brown-headed Gull of Europe
(Larus ridibundus) that Hellmayr (1932, 412) believes the relationship between
the two might possibly be regarded as subspecific. Aplin (1894, 211) states,
furthermore, that in voice and actions the Argentine bird is much like ridibundus,
a fact that had also been noted by Darwin. Both species resort largely to inland
marshes to breed, and neither is restricted to foraging over water but is given
to spending much time in fields and meadows. The Patagonian Brown-hooded
Gull, like its European relative, congregates in great numbers about tilled
grounds, filling a new-made furrow until it appears like a white line, hovering
in a cloud above the plowman’s head and following at his heels, fighting,
screaming, buffeting, in a compact crowd. These words are those of Hudson,
and on page 183 I have already quoted this naturalist’s description of the
manner in which the ‘‘Gaviotas’’ gather along the shores of the Rio de la Plata
after duststorms on the pampas, and of how their flocks take advantage of the
destructive swarms of grasshoppers. For the latter reason, according to Wet-
more (1926, 134), the government of Uruguay furnishes absolute protection to
these gulls and their eggs. Unfortunately, in Argentina they are still killed in
numbers as game, being decoyed within range by means of white objects waved
in the air by the gunners.
The Brown-hooded Gulls breed abundantly on rocky islets along the coast
of the Department of Rocha in Uruguay, and from here southward through
Argentina all the way to Tierra del Fuego. Throughout most parts of this
region, they are the commonest of gulls on the open pampas as well as along
BROWN-HOODED GULL 1085
the coast. The northward limit of the breeding range on the Pacific coast,
according to Hellmayr, probably does not extend much beyond Valdivia.
Wanderers have been recorded from Peru, even as far northward as Callao,
although most of our information seems to be based upon sight records and
should be regarded as unsatisfactory until specimens have been obtained. The
same may be said concerning the reputed abundance of the species about lakes
in the interior of Brazil during the winter, because the collections of the
Brewster-Sanford Expedition show clearly that it is sedentary even as far south
as Ushuaia and the islets near Cape Horn. Its winter migration appears to
consist of a local dispersal of the birds over a larger extent of territory, rather
than of a definitive movement toward zones of different climate.
Wetmore found these gulls common in the eastern part of the Province of
Buenos Aires during October and November, which was the beginning of their
breeding period. At this season adults were found in pairs, circling over pools
of water on the pampa, and flying forward to examine an intruder while uttering
a scolding kek-kek-kek. The call-notes as well as the slow flapping flight were
strongly suggestive of Franklin's Gull. Friedmann (1927, 164) speaks of the
deliberate strokes of Brown-hooded Gulls, as contrasting with the more rapid
wing action of its neighbor, Larus cirrocephalus.
The nesting habits seem to be similar throughout the range of the species,
the Brown-hooded Gulls assembling in flocks during November and early
December at lakes or marshes not far back from the sea, or to sluggish stretches
of river courses about which there is a good growth of grass and reeds. They
make bulky nests and lay three or rarely four eggs which are ‘‘a great delicacy, re-
sembling those of the Plover in taste and appearance and are consequently much
sought after’’ (Sclater and Hudson, 1889, 199). Several hundred nests are some-
times spaced close together, and at daybreak the breeding gulls rise overhead
and hover in a cloud, producing a noise which can be heard at a long distance.
From the Falkland Islands, there may be a partial autumn movement of
these gulls toward the continent, as is true of certain other species, for Abbott
(1861, 166) speaks of Brown-hooded Gulls returning to the islands annually
about July 25, ‘almost to the day.’’ The species is not now particularly abun-
dant at the Falklands, although there are a number of rookeries on isolated tus-
sock islets, and also about the borders of lakes and ponds on certain of the
larger islands, sometimes as far as 5 to 6 kilometers back from the sea. Vallentin
(1924, 302) records colonies at the Jason Islands and elsewhere in West Falkland,
especially in the neighborhood of penguin centers. Beck found the species
beginning to lay in East Falkland on December 10, 1914, the nests being placed
on somewhat trampled tussock hummocks which grew on a small islet in a
pond. South American Terns (Sterna hirundinacea) were nesting about the
borders of this colony, and at a neighboring islet the Kelp Gulls were engaged
in the same process. At this date, various Brown-hooded Gulls’ nests contained
two or three eggs each, all of which were fresh. Many of the eggs, as has been
pointed out by others, resembled those of the South American Tern, being only
slightly larger.
1086 OCEANIC BIRDS OF SOUTH AMERICA
The grasshoppers and the grubs of earth-boring beetles, which the gulls
capture themselves or steal from the lapwings, and also the diet that they seek
nowadays about the slaughterhouses and the garbage dumps of ranches, pertain
alike chiefly to the non-breeding season, when these birds are distributed far
and wide over the pampas. At such times, as Peters (1923, 291) has said, they
will come to feed not only upon the offal of slaughtered sheep, but will pick up
kitchen scraps and even eat the bodies of birds tossed out to them by an ornitho-
logical collector. At their breeding grounds, however, they feed much more
extensively upon live fish, displaying with the terns great excitement when
schools approach the shore. Like most of the other gulls they are always ready
to steal the eggs or young of such birds as moor-hens, and they have been ob-
served hawking about in the air after winged-ants (Gibson, 1920, 81). At the
Falklands, according to Cobb (1933, 33), they rifle the night herons’ nests,
although the bulk of their hunting is done along the beaches. Here they hover
and scramble at the edge of the washed-up kelp, pretending not to like wetting
their feet, screaming and jumping clear whenever a wave runs up, like a crowd
of paddling girls.
SWALLOW-TAILED GULL
Creagrus furcatus
Larus furcatus Néboux, 1846, Voy. ‘Venus,’ Atlas, Zool., Ois., pl. 10 (‘‘Monterey’’ = Galapagos
Archipelago).
Names: There appear to be no synonyms of the specific name.
Characters: The only gull with a pronouncedly forked tail; distinguishable also by the large
and conspicuous triangular white patch on the wings, the great length of the wings, and the slender
pointed bill, all of which give this species a somewhat tern-like aspect.
Adults in breeding plumage (sexes alike): Head and neck covered with a dark gray hood,
broken by a white stripe on each side of the forehead; mantle neutral gray, the wing coverts darker,
the scapulars and tertials with narrow white edgings which enclose the back within a white line;
rump darker gray, the upper tail coverts abruptly white; ventral surface white, the throat and
breast with a pronounced rosy tinge; primaries sharply pointed, dull black, with conspicuous white
tongues covering the greater part of the inner webs, the median series of these quills with whitish
apical spots, the inner series mostly or wholly white or gray; primary coverts dusky on inner webs,
but gray to white on outer; secondaries pale gray, becoming white on the proximal quills; tertials
gray, narrowly edged with white; greater and median coverts white, with pale gray edgings; tail
white. Iris brown; eyelid crimson; bill basally black, bluish or greenish distally, beyond the nos-
tril; rictus crimson; skin of interramal space salmon color; tarsus and toes peach-blossom-pink;
webs geranium-pink, shaded with black at the edges.
In non-breeding plumage the head is white, obscurely streaked on the occiput with gray, which
passes into an ill-defined collar contrasting with the paler neck; a slight auricular spot is dusky,
and the eye is surrounded by a broad spectacle of grayish black; the throat is more or less clouded
with pale gray, its sides markedly so; the bill is much darker than at breeding time, being pre-
vailingly black except toward the tip; the legs are dull reddish ochre, with the feet more distinctly red.
8 males: wing, 405-433 (414.8); tail, 184-202 (191.1); exposed culmen, 47-55 (52); tarsus,
45-55 (52.1); middle toe without claw, 44-52 (48.5) mm.
8 females: wing, 393-414 (404.1); tail, 181-197 (189.7); exposed culmen, 49-52 (50.9); tarsus,
47-54 (51); middle toe without claw, 44-50 (47.1) mm. (Dwight, 1925, 325).
Length in the flesh: 5 males, 571-606; 3 females, 550-573 mm. Wing-expanse: 5 males, 1362-
1392; 3 females, 1241-1330 mm. (Gifford, 1913, 417).
In juvenal plumage the mantle is clove-brown, with broad white feather edgings; the feathers
of back largely white basally, with irregular subterminal bars; rump and upper tail coverts grayish,
SWALLOW-TAILED GULL 1087
marked with brown; head white, with pale brown edgings on the occiput, the neck becoming
gradually pale clove-brown, which merges into the darker back; auriculars and eye-crescent dusky,
the lores partly brown; ventral surface white; primaries similar to those of adult plumage, but with
less extensive white tongues; secondaries and alula white, the greater coverts with pale gray
edgings, the median coverts and tertials darker gray; primary coverts dull black; lesser coverts
brown like the back, and similarly edged with white; tail white, with a terminal dul] black band
20-30 mm. in width, the rectrices narrowly white-tipped, the outer pair with only one or two
slightsmudges orspots. Bill dull black, the mandible basally brownish flesh color; feet grayish white.
Natal down not seen, but Dwight (1925, 377) refers to ‘the white and speckled"’ pattern as it
shows in photographs. Gifford (1913, 40) states that there are both protoptyle and mesoptyle
generations of down in this gull, and that the second series is brownish gray on the dorsal surface,
ventrally chiefly white, shading to pale gray on the throat and chin.
Eggs generally resemble those of other gulls, and vary in a similar manner. They are more or
less regularly ovate. Most specimens are very light greenish or bluish white, with large, bold
spots, patches of dark brown, and underlying grayish mauve spots. The spots may be either spread
all over the egg, or accumulated near the larger end in a patch or an irregular ring. In some eggs
the ground color is of a brownish or light reddish, but all appear light sea-green when held against
the light. Examples measure 64 x 47.5, 66 x 46.5, 66 x 46, 60 x 44.5 mm. (Rothschild and Hartert,
1899, 190). Gifford records the average dimensions of 36 as 66.3 x 45.9 mm.
Distribution: Breeding at the Galapagos Islands and probably at Malpelo Island, and migrating
to the west coast of South America between Ecuador and southern Peru.
The handsome Swallow-tailed Gull, which can be readily distinguished at
sea because of the large triangular white patch on its long wings, is a surpris-
ingly common and conspicuous bird in waters well out from shore along the
coast of Peru. Unlike the Dusky Gull of the Galapagos, it makes a lengthy
annual migration away from its nesting ground. The movement seems to be
individual or sporadic rather than seasonal, however, for Swallow-tailed Gulls
have been observed and collected off Peru at many different seasons of the year.
This is doubtless the type of migration to be expected of a species having a
breeding season of the continuous, tropical-island type.
Streets (1912, 233) calls attention to the fact that the Swallow-tailed Gull
is not in the usual sense a littoral bird, like most of its relatives, but is to a cer-
tain extent pelagic even during the breeding period. On a voyage between
Callao and Acapulco, this author passed within sight of Chatham Island, the
easternmost of the Galapagos, and up to distances of 500 kilometers or more
from the island, both when approaching and departing, he observed gulls of
this species over the high sea, on lines of flight proceeding away from the
atchipelago in the morning and toward it at evening. Throughout three days’
sail this phenomenon was observed. Gifford also speaks of the powerful flight
of the Swallow-tailed Gull, and of the fact that the California Academy party
observed it at sea upwards of 250 kilometers to southwestward of Albemarle in
June, and almost as far to eastward of Chatham in September.
The nesting grounds are at many if not all islands of the Galapagos, and
were formerly supposed to be confined to the archipelago. Townsend (1895,
121), however, obtained specimens of this gull at the little island of Malpelo,
which lies in latitude 4° N., close to a line drawn between the Galapagos and
Panama. Townsend concluded that the species is ‘doubtless abundant there."’
Swarth (1931, 66) states that one or more stragglers have been taken at Panama,
1088 OCEANIC BIRDS OF SOUTH AMERICA
which is not surprising in view of Streets’ notes on the long reach of the
daily flight.
The American Museum possesses several Galapagos specimens of this gull
obtained through exchange with the California Academy of Sciences, as well
as a female collected by Beck on the ocean about 16 kilometers west of Pisco,
Peru, on June 28, 1913, and a male taken by myself 13 kilometers west of Talara,
Peru, on January 20, 1925. The latter two birds were in non-breeding condition,
as might be expected. Beck’s specimen is one of a group of three which he saw
in the Pisco Bay region. His notebook also mentions others sighted south of
Salaverry on January 5, outside the Bay of Callao on January 6, and off Ancén on
May 12, 1913. Jaques reports groups off Salaverry, Callao, and Pisco during
February and March, 1925, while in the course of my own field work I saw the
species as follows:
Off the Bay of Ferrol, December 31, 1919, 50 or more together; between the
islands of Lobos de Afuera and Lobos de Tierra, January 6, 1920, several flocks;
off the Gulf of Guayaquil, January and February, 1925, several small groups;
in the harbor of Callao, December 8, 1924, several birds; far offshore from
Mollendo, January 19, 1925, a number.
According to Gifford, the Swallow-tailed Gull is common at the Galapagos
throughout the year. Its nesting period is also continuous, for eggs have been
taken during eight different months, and chicks in one nest are often found
close to fresh eggs in others. Only one egg is laid, the site rarely being more
than a slight scrape or depression lined with fragments of stone.
In flight, these gulls have a pulsating upward and downward movement of
the body with each stroke of the wings. They usually travel singly or in small
flocks. At times they soar high in the air, their descent to the water from such
altitudes being a series of swooping spirals, like those of the man-o’-war birds.
Streets calls attention to the shyness or indifference of the birds on the high sea.
They neither hovered about his vessel, nor showed the slightest interest in it.
During my own work along the coast of Peru, I was constantly impressed by
the strange wariness of these gulls, which are so utterly fearless when ashore
at their breeding grounds. Ordinarily a migrant flock on the water will take
flight when a small boat is still at a great distance.
The man-o'-war bird seems to be the principal enemy of the adult Swallow-
tailed Gulls, often pursuing them through complicated aérial evolutions in
order to make them disgorge, and not hesitating to torture as well as to frighten.
Gifford saw one of a team of two pirating man-o’-war birds seize the foot of a
fleeing Swallow-tailed Gull, apparently dislocating its leg, which afterwards
hung down limply. The young gulls are not infrequent victims of the Gala-
pagos hawks.
The principal food of the species consists of squids, examples of which are
commonly disgorged by both young and adults. The California Academy party
also saw these gulls pursuing schools of surface fish, while the stomachs of
specimens taken at sea contained remains of pteropods and of marine water-
striders (Hydrometridae).
BLACK TERN 1089
BLACK TERN
Chlidonias nigra surinamensis
Sterna surinamensis Gmelin, 1789, Syst. Nat., 1, pt. 2, p. 604 (Surinam).
Names: The American Black Tern has appeared in the literature under several other names,
including plumbea, exilis, frenata, fissipes, and lariformts.
Characters: A small, short-billed, generally dark-bodied tern, with a short and only slightly
forked tail, the head, neck, and breast black in breeding plumage but gray and white at other
seasons.
Adults in summer (sexes alike): Head, neck, and under parts, except under tail coverts and
anal region, uniform sooty black or grayish black (blackish fuscous or fuscous black to chaetura
black, varying, rarely, to deep purple-gray ); under tail coverts and anal region immaculate white;
back and scapulars, rump, upper tail coverts, tail, and wings deep neutral gray or purple-gray, the
wings somewhat lighter (neutral gray); edge of wing, from body to carpometacarpal joint, white;
axillars and under wing coverts light neutral gray; bill black, the rictus purplish red Cin life);
interior of mouth lavender-pink (in life); iris dark brown; legs and feet dusky livid purplish
Cin life).
Adults in northern-hemisphere winter: Head, neck, and under parts white, the orbital and
auricular regions dusky, the crown and occiput dark grayish, the feathers margined with paler;
upper parts (except as described) as in summer.
10 adult males: wing, 192-213 (203.2); tail, 73-87.5 (79.8); exposed culmen, 26-29.5 (27);
tarsus, 14.5-16 (15.4); middle toe [without claw], 15-16 (15.6) mm.
10 adult females: wing, 191-215 (199.6); tail, 73.5-82 (77.8); exposed culmen, 25.5-27 (26.2);
tarsus, 14-16.5 (15.6); middle toe [without claw], 14.5-16.5 (15.5) mm.
Young: Similar to winter adults, but scapulars, interscapulars, and tertials tipped with light
buffy brownish, anterior lesser wing coverts dusky, crown, occiput, and nape dusky, and sides
and flanks washed or tinged with gray (Ridgway, 1919, 532).
Distribution: Breeds in northern North America, southward to California, Kansas, northern
Tennessee, Ohio, and western New York. Migrates southward over Mexico and Central America
and winters in South America, from Dutch Guiana to Peru and Chile.
Except for scattered captures of individual examples, little seems to be known
about the Black Tern throughout its extensive winter range in South America.
It was not encountered by Mr. Beck during the course of the Brewster-Sanford
Expedition, but one of Dr. Chapman's parties collected a male on the coast of
Manavi, Ecuador, on February 13, 1913. I suspect that I saw a large flock of
Black Terns off the Chanduy coast of the Gulf of Guayaquil, just before dawn
of February 11, 1925. The visibility was, however, very poor, and I obtained
no specimens in the region. Rendahl (1920, 27) found the species at the Pearl
Islands, Gulf of Panama, during April. In the British Museum is an example
from Callao, Peru, and Hellmayr (1932, 408) records this tern as an occasional
winter visitor to Chile.
The Black Tern is a bird of inland marsh regions, apparently approaching
the sea only during migration. It does not nest close to salt water. In keeping
with its generally terrestrial habits, it feeds largely upon insects, and is capable
of capturing moths and even dragon flies upon the wing. During the parts of
the year in which it follows the coast or crosses arms of the sea, it associates
commonly with other terns, and at such times plunges for small fishes and
crustaceans in the usual manner.
1090 OCEANIC BIRDS OF SOUTH AMERICA
LARGE-BILLED TERN
Phaetusa simplex
This fluviatile tern comprises two subspecies CP. s. simplex and P. s. chloro-
pada), the first of which is found in the river basins of northern South America
while the second seems to be confined to the Paraguay-Parana drainage (Wet-
more, 1926, 141). The original citations of each are as follows:
Sterna simplex Gmelin, 1789, Syst. Nat., 1, pt. 2, p. 606 (Cayenne).
Sterna chloropoda Vieillot, 1819, Nouv. Dict. Hist. Nat., 32, p. 171 (Paraguay).
Names: In Argentina and certain other parts of Spanish-speaking South America this tern is
known as the ‘“‘Ati,’’ ‘“Gaviotin,”’ or ‘‘Martin Pescador’; in Brazil it is called “‘Andorinha do
Mar."’ The commonest synonym for the specific name is magnirostris; other names that have ap-
peared in the literature are speculifera and albifrons.
Characters: A large, exceedingly heavy-billed tern, with a relatively very short tail.
Adults in breeding plumage (sexes alike): Pileum, nape, and auricular region uniform black,
this descending to anterior angle of eye and extending along median line of hind neck; back,
scapulars, proximal wing coverts, tertials, rump, upper tail coverts, and tail plain deep neutral
gray; distal smaller wing coverts, secondaries, greater wing coverts, lores (sometimes anterior
margin of forehead, narrowly), and under parts immaculate white, the sides and flanks more or less
strongly tinged with pale or pallid neutral gray, the sides of neck deeper gray; primary coverts
and primaries dull black, the innermost primaries with inner webs more grayish and margined
terminally with white; inner webs of primaries with an extensive white ‘‘wedge,’’ especially the
outermost; bill yellow, more or less tinged with grayish or horn-color basally; legs and feet grayish
dusky (said to be olive, with yellow webs, in life) (Ridgway, 1919, 541).
The above applies to the northern South American race. In Phaetusa simplex chloropoda, from
Paraguay and northern Argentina, the hind neck, back, scapulars, lesser wing coverts and tail are
definitely lighter gray than in the typical race. The flesh colors, according to Wetmore (1926, 140),
are: bill lemon-chrome, becoming light cadmium at base of culmen; tongue and inside of bill
lemon-chrome, becoming cress-green toward the fauces; iris fuscous; tarsus and toes primuline
yellow; claws dull black at tip, changing at base to gray.
7 adults (of both sexes) from Ecuador, Colombia, Venezuela, and Brazil: wing, 296-314 (303.3);
tail, 105.5-119.3 (112.7); culmen, 61.5-70.2 (65.3); depth of bill at base, 18-21 (19.3); tarsus,
24-27 (25.8); middle toe and claw, 29-31.2 (29.8) mm.
Immature: Essentially like adults but pileum light gray, deepening into black on auricular
region and near anterior angle of eye; back, etc., pale gray (between light neutral gray and light
mouse-gray); secondaries more extensively gray than in adults; white of distal wing coverts tinged
with gray and metacarpal region mostly gray; primary coverts and primaries duller or more brown-
ish black, and bill duller yellow and more tinged with horn-color or olive.
Young: Similar to the immature plumage, but feathers of pileum broadly tipped with vinaceous-
buff or pale ochraceous, and with mesial streaks of black; interscapulars and anterior scapulars
(sometimes proximal wing coverts also) more or less distinctly margined terminally with vinaceous-
buff or pale avellaneous, the posterior scapulars very broadly tipped with the same, the tertials
tipped or terminally margined with pale buff or buffy white; feathers of rump, upper tail coverts,
and tail tipped with dull vinaceous buff or pale avellaneous; white of lores and blackish post-
ocular area tinged or suffused with pale avellaneous (Ridgway, 1919, 541).
Eggs of the southern form of the Large-billed Tern taken on sandbanks opposite Bellavista on
the Rio Parana numbered two or three. They were of a yellowish ground color overlaid with
large ash-colored blotches and upon these smaller spots of reddish brown. Measurements of an
unstated number showed lengths varying between 46 and 51.5 mm. and breadths between 35 and
37 mm. (Hartert and Venturi, 1909, 253).
Distribution:
Phaetusa simplex simplex: Coasts and larger rivers of northern and eastern South America from
LARGE-BILLED TERN 1091
Ecuador, Colombia, Venezuela, the Guianas, and the northeastern coast of Brazil, southward to
Amazonian Peru.
Phaetusa simplex chloropoda: Estuaries and larger rivers of southern South America from eastern
Bolivia, Matto Grosso, and Sao Paulo, south to northern Argentina.
The Large-billed Tern is far more a bird of broad streams than of the coasts,
and the two well-marked subspecies divide the great drainage basins of the
continent between them, apparently ascending well toward the headwaters.
The preference of the birds runs toward rivers of considerable size and depth,
which is doubtless the reason why they have never invaded to any great extent
the South American waters of Pacific drainage. MacFarlane (1887, 209) reports
these terns as flying over the River Guayas, off Guayaquil, during evenings of
May and June, and Peters (1934, 329) remarks that they have been ‘‘recorded
from western Ecuador.”’ All such specific records are, however, scarce, whereas
along the lower stretches of the Rio Magdalena, and other streams flowing
toward the Caribbean, the bird is abundant (Chapman, 1917, 221). Along the
Caribbean coast the Large-billed Tern has been recorded at Margarita and other
outlying islands (Cory, 1909, 233), although it is much more in evidence about
the mouths of rivers on the mainland coasts, as at Cumana, Venezuela, where
it often swarms among the flocks of pelicans (Robinson, 1895, 653). Beebe
(1909, 74) reports it in the delta of the Orinoco, perching occasionally on the
mangrove snags and then resuming its flight and headlong plunges. Both
Schomburgk (1848, 76) and Young (1928, 765) state that it is common along
the whole sea front of British Guiana throughout most of the year, although
it nests only on sandbanks far up the streams between May and August. Along
this coast of mingled muddy streams and turbid sea, the Large-billed Terns
appear indifferent as to the salinity, or even the translucency, of the water in
which they contrive to find their prey. They scout about at a good height
above the surface, then plunge, and subsequently carry their catch high into
the air to swallow it while on the wing. Their activities are greatest about
sunrise, when flocks of the birds pursue the shoals of small fish.
The Large-billed Tern is recorded from many localities along the Brazilian
coast, between the waters about Mexiana Island, in the mouth of the Amazon,
and the Uruguayan border, but the point at which the northern and southern
races come into contact, if they do, is still to be determined.
In the Province of Buenos Aires, Argentina, where the southern subspecies
of the Large-billed Tern reaches the seacoast, it appears to remain an almost
exclusively fresh-water bird, limiting its range in the estuary of the Rio de la
Plata to a point inside the line of blue water. The southern race is thus even
less marine than that of tropical coasts.
Wetmore (1926, 140) calls attention to the peculiarly robust appearance that
these birds have in the air, owing to their huge bills. He states that they fre-
quently swing up toward an intruder to examine him curiously, or to scold
with harsh, raucous calls. At such times the yellow bill is especially prominent.
Durnford (1877, 200) states that the ordinary note of the Large-billed Tern is
much like the cry of the Tero-tero or Argentine Lapwing.
1092 OCEANIC BIRDS OF SOUTH AMERICA
GULL-BILLED TERN
Gelochelidon nilotica
Sterna nilotica Gmelin, 1789, Syst. Nat., 1, pt. 2, p. 606 (Egypt).
At least three forms of the Gull-billed Tern have been described from
America, among which Wilson's name has priority. Specimens are not avail-
able for an adequate revision, and Peters (1934, 330) was unable to decide to
which of several alleged forms various South American records pertained.
Following are three citations of original descriptions, any or all of which may
refer to South American examples of this tern.
Sterna aranea Wilson, 1814, Amer. Orn., 8, p. 143, pl. 72, fig. 6 (Cape May, New Jersey).
Gelochelidon nilotica grénvoldi Mathews, 1912, Birds Australia, 2, p. 331 (South America).
Gelochelidon nilotica vanrossemi Bancroft, 1929, Trans. San Diego de Nat. Hist., 5, p. 284 (Salton Sea, Im-
perial County, California).
Names: In South American writings this tern is sometimes called “Gaviotin de Pico Negro.”’
Common synonyms for the specific name are anglica, aranea, affinis, meridionalis, macrotarsa, and
alustris.
S Characters: The short and stout black bill distinguishes this tern from any other within our
region; another peculiarity is the long tarsus which considerably exceeds in length the middle toe
with claw.
Adults in breeding season (sexes alike): Pileum, nape, and upper half of lores uniform deep
black; rest of upper parts, including rump, upper tail coverts, and tail, uniform pale gray (between
gull gray and pallid neutral gray); entire under parts, including sides of head up to and including
auricular and suborbital regions and lower half of lores, together with axillars and under wing
coverts, immaculate pure white; bill wholly deep black; inside of mouth flesh color Cin life);
iris dark brown; legs and feet dark reddish brown (dark walnut-brown) in life, the soles of toes
pinkish brown.
Adults in northern-hemisphere winter: Head and neck white, the hind neck tinged with pale
gray, the auricular region and a crescentic space immediately in front of eye dusky grayish; other-
wise as in summer (Ridgway, 1919, 479).
Measurements of 3 males and 2 females from the Gulf of Guayaquil, Ecuador, and Mar del
Plata, Argentina, agree well with those of 20 specimens from both Old- and New-World localities
recorded by Ridgway, and are as follows: wing, 295-306 (304.6); tail, 115-121 (117.8); exposed
culmen, 37.3-39.6 (38.6); tarsus, 30-33.1 (31.5); middle toe and claw, 28-30.8 (29.2) mm.
Young: Upper parts pale gray, the feathers more or less tipped with pale clay color or dull buff,
this sometimes nearly uniform on back and scapulars, where the gray is mostly concealed, the
pileum and hind neck, as well as back and scapulars, sometimes streaked with dusky, but oftener
immaculate; a blackish crescentic spot immediately in front of eye, and a dusky grayish suffusion
on upper portion of auricular region, forming a more or less distinct post-ocular stripe; rump,
upper tail coverts, tail, and wings nearly uniform pale gray; remiges deeper, more silvery, gray,
the secondaries and proximal primaries tipped or terminally margined with white; rectrices darker
gray subterminally and tipped with white or buffy; under parts immaculate white; bill dusky
brownish, the mandible dull brownish orange, dusky terminally; legs and feet varying from dull
reddish brown to dusky brown Cin life), the soles more reddish.
Downy young: Upper parts light grayish buff with several large and tolerably well-defined
dusky irregular spots on posterior half of head, a distinct dusky stripe down each side of hind neck
and upper back, the wings, rump, and flanks with rather distinct large spots of dusky; under parts
white, tinged with grayish on sides of throat; bill brownish inclining to orange Cin life) on man-
dible; legs and feet brownish orange (in life) (Ridgway, 1919, 480).
Eggs: Bent (1921, 199) writes as follows regarding the eggs of this tern: the Gull-billed Tern
raises but one brood in a season and lays ordinarily two or three eggs; sets of four eggs are occasion-
GULL-BILLED TERN 1093
ally laid, but they are uncommon. The eggs are characteristic and are easily recognized by their
size and shape. In general appearance they are rounder and lighter colored than the eggs of any
of the medium-sized terns. In shape they are usually ovate or short-ovate, well rounded at the
small end. The ground color varies from ‘‘warm buff”’ or ‘‘pinkish buff’’ in the darkest eggs to
“‘cartridge-buff’’ or “‘ivory-yellow’’ in the lightest eggs; the prevailing colors are the lighter
shades of buff. The markings consist of spots and blotches of various sizes and shapes scattered
irregularly over the egg in varying amounts, but the majority of the eggs are not very heavily
marked. The underlying spots show all five shades of ‘brownish drab,"’ and the heavier markings
are in various shades of the darker browns, such as ‘‘Vandyke brown,”’ “‘bister,’’ and ‘‘sepia."’
The measurements of 47 eggs in the United States National Museum average 47 x 34 mm.; the eggs
showing the four extremes measure 51 x 35.5, 49 x 36, 44 x 33.5, and 46 x 32.5 mm.
Distribution: Of nearly cosmopolitan range but absent from the colder regions. In America
the species breeds from the Atlantic and Gulf coasts of the United States and southern California
southward presumably to Ecuador or northern Peru and to southern Brazil or beyond.
As will be seen from the discussion of names above, the distribution and
races of the Gull-billed Tern in South America can hardly be determined until
additional study has been preceded by more extensive collecting. Mathews’s
highly casual statement that his proposed race, grénvoldi, from ‘South America,”’
has a longer bill than North American specimens, proves not to hold among
the skins I have examined.
According to Peters (1934, 330), the subspecies recently described from
southern California winters on the west coast of America, southward to Ecua-
dor. However, the Gull-billed Tern is in all probability a resident bird, as
well as a migrant, in Peru and Ecuador, which indicates that the existing sub-
specific names have been created far in advance of any adequate study of the
facts.
In the course of my work in the Gulf of Guayaquil, I observed examples of
this well-marked tern off the southern coast of Puna Island on February 26,
1925. This date is in the middle of the northern winter, but Chapman (1926,
185) records specimens from Jambeli Island, taken during July, 1922, when the
testes of the males were slightly enlarged, and from Vaqueria, Ecuador, during
September of the same year. An additional specimen was collected in the Gulf
of Guayaquil during November, 1921.
On the east coast of South America, Mexiana Island, at the mouth of the
Amazon, and various localities along the southwestern coast of Brazil, are
alleged to be breeding stations (Peters, 1934, 330). Dabbene (1918, 136) im-
plies that the birds encountered on the coast of Argentina, between the Rio de
la Plata and Bahia Blanca, are migrants from more northerly nesting grounds.
Wetmore (1926, 136) encountered this tern in small numbers near Bahia
Blanca during December, 1920, and again near Carrasco, Uruguay, during the
following month, when several were seen in company with Royal Terns. At
Ingeniero White, in the Province of Buenos Aires, he watched Gull-billed Terns
feeding over shallow bays, or resting on muddy points. They circled about,
with chattering calls, and frequently dived for small fishes in the tidal channels.
One flew over his head, carrying one of the common crabs of the “‘cangrejales”’
(Chasmagnathus granulata) in its bill; after alighting in shallow water it pulled
off the creature's claws and then swallowed it.
1094 OCEANIC BIRDS OF SOUTH AMERICA
During the Brewster-Sanford Expedition, Mr. Beck took a male and a female
of this species, each with much enlarged gonads, at a pond north of Mar del
Plata, Argentina, on October 27, 1914. These, and the Ecuadorian birds referred
to above, are the only South American specimens in the American Museum
Collection.
In North America the Gull-billed Tern is much of a marsh bird and, like the
Black Tern, is said to feed largely upon insects. In its breeding habits, however,
it chooses either grassy territory or shell-strewn sea beaches and, under the
latter condition, it may build a large pile of jetsam for a nest. Sometimes it
breeds in small groups of its own kind, but perhaps more frequently the nests
of Gull-billed Terns are distributed among those of other species. Thus at an
island colony on the Texas coast, the Gull-bill was but one of seven different
terns, ranging in size between the Least Tern and the Caspian, all closely asso-
ciated within a relatively small space.
SOUTH AMERICAN TERN
Sterna hirundinacea
Sterna hirundinacea “‘Cuy."’ Lesson, 1831, Traité d’Orn., livr. 8, p. 621 (coast of Brazil, é.e. State of Santa
Catharina).
Names: Cassin’s Tern; Fork-tailed or Swallow-tailed *‘Gull’’ in the Falkland Islands; *’Ter-
recle’’ in Peru, and “‘Chibrillo,”’ ‘‘Chiliuta,’’ ““Golondrina de Mar,"’ ‘‘Corbinero,”’ or “‘Gaviotin”™’
in other parts of Spanish-speaking South America; *‘Trinta Reis’ applies in Brazil to this or almost
any other tern. The name Terrecle is imitative of the notes, and is curiously like the term ‘‘terrick”’
of Scotland and “‘carrick’’ of the British West Indies, both of which are applied to terns. In
scientific literature the South American Tern has been listed under the specific names acutirostris,
antarctica, meridionalis, and cassinit.
Characters: Larger than any of its near relatives, and with a long, somewhat curved bill.
While the species evidently has certain affinities with Sterna vittata, the breadth of the band on
the upper wing coverts of immature birds indicates, according to Saunders (1896, 53), a relation-
ship with the northern-hemisphere S. hirundo.
Adults in breeding plumage (sexes alike): Pileum, greater part of lores, and nape black,
bordered by an inferior white streak running caudad from the gape; neck, mantle, throat, and
breast pale pearl-gray, passing into white toward the vent, the secondaries and inner primaries
broadly margined with white; rump and tail white, with a gray tinge on the outer webs of the
rectrices. Iris brown; bill, legs, and feet vermilion.
Adults in winter: Plumage generally lighter than in summer, especially ventrally; forehead
and crown mottled black and white; bill and feet of duller red. Among most examples an active
moult begins in April.
21 males from Peru, central Chile, the Magellanic region, the Falkland Islands, northern
Argentina, and Brazil: wing, 284-315 (296.2); tail, 161.5-219 (183); maximum fork of tail, 143.4;
exposed culmen, 40-44 (42.1); tarsus, 19-23 (21.6); middle toe and claw, 24.1-28.5 (27) mm.
8 females from Chile, the Magellanic region, Falkland Islands, northern Argentina, and Brazil:
wing, 291-305 (298); tail, 172.5-185.4 (181); exposed culmen, 39.5-42.4 (40.6); tarsus, 20.9-22.1
(21.5); middle toe and claw, 26-29.5 (27.5) mm.
Measurements in the flesh of two specimens from Rio de Janeiro were: male, length 432, wing-
spread 832; female, length 444, wing-spread 775 mm.
In immature examples, the gray tinge is heavier throughout. Younger birds retain a somewhat
plover-like plumage, with strongly barred, buffy and blackish feathers, a streaked pileum, and
buffy flecked and speckled breast and flanks, even longer than the young of vittata. Birds which
SOUTH AMERICAN TERN 1095
have been flying for several weeks still remain relatively dark. The bill is blackish, and the legs
and feet dull orange.
In nestlings the dorsal surface is olive-brown, with darker brown mottling, the throat blackish,
and the remainder of the ventral surface dirty whitish.
Eggs are extraordinarily variable in ground color, as are those of most terns, this ranging
between pale greenish or buffy white and a rich olive-brown. The overlying spots and blotches
vary from relatively fine speckling to solid irregular marks 20 mm. or more in diameter. The
markings are prevailingly brown, the density of the color depending upon whether the pigment
lies directly on the surface or somewhat beneath it. When two eggs constitute a set, these gener-
ally tend to resemble each other in the type of outer marking. The shape of the eggs is likewise
variable, ranging between ovate and short-ovate, with an occasional pyriform example.
Sets of two from East Falkland, collected December 10, 1915, measure as follows: 45.9 x 33.6
and 44.5 x 33.5; 41.4 x 33.7 and 42.2 x 33.7; 44.7 x 33.7 and 47 x 33.7; 47 x 34.9 and 45.8 x 34.9;
46.2 x 34.7 and 45.9 x 34.3; 45.8 x 35.6 and 46.5 x 34 mm. A set of two from Pouchet Island,
Chile, December 1, 1914, measures 46.8 x 35.4 and 45.4 x 35.7 mm. Among sets of single eggs
from Pouchet and other islets in the Cape Horn region, the extreme measurements are as follows:
49.4 x 34.8, 47.1 x 30, 45 x 41 (pyriform), 45.2 x 33.8 mm.
Distribution: Breeds on both coasts of central and southerly South America, from San Gallan
Island (and probably northward), Peru, and from the neighborhood of Cape Frio, Brazil, south-
ward to the Falkland Islands, Tierra del Fuego, and Cape Horn. Wanders northward to northern
Peru (Pacasmayo) and to Bahia, Brazil. Records of this tern from the South Orkney and South
Shetland Islands, and other localities in the American Antarctic, prove to be erroneous, and are
based upon another species (Sterna vittata).
This handsome red-billed tern, the largest member of its group within the
genus Sterna, may with particular appropriateness be known as the South
American Tern, a name perhaps first bestowed upon it by Alexander (1928, 166),
for it is a species confined entirely to the South American continental coasts and
to such closely adjacent islands as the Falklands. Its reputed residence at the
South Shetlands and South Orkney Islands now proves to be due to confusion
with another species (Sterna vittata) which, in the form of two or more geo-
graphic races, is the only tern inhabiting islands within the Antarctic Zone of
surface water in the American quadrant of the south polar regions.
The Brewster-Sanford Expedition, and other South American field work on
behalf of the American Museum of Natural History, have yielded a large series
of these terns from many parts of the continental coast and the Falkland Islands.
Mr. Beck's specimens include adults in full summer plumage, and in breeding
condition, taken at Ancén and San Gallan Island, Peru, during May and July,
1913, and many adults with enlarged gonads, as well as several young birds,
taken at Valparaiso and Corral, Chile, during September, October, and March
of the same year. Later, Beck collected a large series of birds in all stages of
growth at the following localities: Ancid, Chiloé Island, April and May;
Magallanes and elsewhere in the Strait of Magellan, Caroline Island, and Cape
Horn, November, December, February, and March; the Falkland Islands,
November and January; Mar del Plata, Argentina, September and October; Rio
de Janeiro, May. In addition, the Museum possesses specimens taken at Tofo,
Chile, in June by Mr. Thomas Hallinan, and others collected at Rio de Janeiro
in June and July during the South Atlantic Expedition of the Cleveland Museum
of Natural History.
1096 OCEANIC BIRDS OF SOUTH AMERICA
Throughout the cool-water littoral of South America, <his tern fills a zodgeo-
graphic rdle similar to that of the Kelp Gull, although the northern limit of its
breeding range on either coast is less accurately known. In any event, its dis-
tribution practically supplements that of such pan-tropical sea fowl as the man-
o’-war birds. The ranges of Sterna hirundinacea and of Fregatu magnificens may
be said to meet, but scarcely to overlap, on both the Atlantic and Pacific sides
of the continent, the former bird being a symbol of cool upwelling water as
the latter is of tropical surface water (cf. Fig. 23, p. 165).
For such reasons the northernmost breeding outposts of the South American
Tern in Brazil and Peru are of critical interest, and further information is needed
concerning them. The species is reported as a common winter visitor to Sao
Paulo (von Ihering, 1907, 40) and even northward to Bahia (Dabbene, 1917,
138). It probably nests near Rio de Janeiro or Cape Frio (Bennett, 1920, 25),
though the records of Aplin (1894, 210) and Alvarez (1933, 7) for islets off the
Banda Oriental and the eastern coast of Uruguay are suggestive rather than
fully satisfactory.
In the Humboldt Current region this tern is abundant at all seasons of the
year, and it seems extraordinary that Peruvian breeding records are so scarce.
I found the birds in large numbers in the roadstead of Pacasmayo, Peru, on
January 2, 1920, while in the harbors of Chimbote, Salaverry, Callao, Pisco,
etc., it is a common experience to see them fishing close to passenger steamers,
or being chased about by marauding jaegers on winter migration from the
northern hemisphere. At Independencia Bay, and the little island of Santa
Rosa, Mr. Jaques found this tern to outnumber all other birds during the latter
part of February, 1926. This locality, by the way, is a definitely established
breeding station, for here Coker (1919, 459) found the South American Terns
nesting during the winter season. He writes:
The terrecle is very common in the southern region particularly. The principal breeding places
observed were San Gallan (June 25) and the Islas de Santa Rosa at the Bay of Independencia (July
18, 1907). This was in midwinter. Of the south Santa Rosa, a relatively low, flat-topped island,
the nests lay so thickly on the ground, and the eggs were so inconspicuous among the small stones,
that, despite great watchfulness, one could not walk about without crushing the eggs. The
young birds, however, stood in little danger, since even in the fledgling stage they were wary and
exceedingly active; they would run quickly away even to a distance and become almost invisible
beside a small bit of grave]. No other birds of the islands were observed to be either so active or
so successful in concealment.
In the Magellanic region, the records of the South American Tern are, of
course, exceedingly numerous. Cunningham (1871, 74), Nicoll (1904, 43),
Crawshay (1907, 128), and many other naturalists tell of observations on the
gteat flocks that gather at low tide on the famous sandy spit close to the town
of ‘Punta Arenas’’ or Magallanes. Here they fly in a vociferous cloud above
the head of an intruder, and may be lured within close range by clicking two
flints sharply together and thus producing a sound that excites their curiosity.
Here Beck collected specimens during February and March, 1915.
During subsequent field work, Beck also obtained a considerable series of
eggs of this tern, which show wide variety in shape, ground color, and
SOUTH AMERICAN TERN 1097
markings. In December, 1914, he visited terneries at a precipitous islet off
Caroline Island and at Pouchet and Thiéry Islets, the latter two of which lie
just south of the Hardy Peninsula of Hoste Island, and not far from Cape Horn.
At these places the crews of passing sloops and schooners stopped to gather
bucketfuls of the eggs for food. In January, 1915, the Indians at the Rio
Douglas Mission, on Navarino Island, also laid up a huge supply of tern
eggs from a colony on Vauverland Island in the Gulf of Nassau. Of eleven
sets personally taken by Beck at Pouchet Islet, on December 21, one is com-
posed of two eggs and the remainder of but one. It is probable, however,
that many sets had not been completed at this date. Beck found that most
of the terns here had formed slight nests by picking wisps of grass that
grew Close to the sites.
A second series of eggs is from East Island, Falklands, taken on December 10.
In this instance six of seven sets are made up of two eggs, the other of one.
The nests were on the gravelly beach of a tiny islet in a fresh-water pond, close
to a colony of Brown-hooded Gulls, and were composed of strands of tussock
grass.
Cobb (1933, 31) writes that at the Falkland Islands three eggs in a set
are not infrequent, and that in some nests on sloping tussock land he has
found four or five, but in such instances he judged that two or more of
them were extra eggs which had rolled down from above. Bennett (1920, 25)
infers that the breeding season is relatively long at the Falklands, and
that fresh eggs and well-grown chicks may be observed in many colonies on
the same date.
At Tombo Point, on the coast of Patagonia, Durnford (1878, 404) reports
one, two, or three eggs, and ‘‘no two alike,’’ in nests which were mere hollows
in the gravel of an enormous ternery. Here in December he found an average
of three nests to each square meter of surface over a space 150 meters square, to
the somewhat staggering total of 67,500 nests or 135,000 adult birds. Hartert
and Venturi (1909, 253) refer to a colony on the Isla de Leones at the mouth of
the Rio Santa Cruz.
A wide variety of small fishes and other organisms enter into the diet of this
species. Along the Peruvian coast the terns appear to follow the same shoals
of silversides and anchovies upon which the guano birds subsist. At Corral,
Beck found them plunging for crustaceans which he calls ‘‘young shrimp.”’ In
the coastal waters of Chiloé Island, he saw them diving into the dark surface
of the kelp beds, apparently in search of arthropods of some sort. Frequently
the terns would settle in flocks to rest upon the long strands of the kelp itself.
This species shares a habit common in its family, namely that of exchanging
food with the mate, particularly during incubation. Whether it is only the
male which passes food to a brooding female is not known.
Throughout the Humboldt Current the South American Tern is a favorite
victim of the Parasitic Jaeger. On several occasions, however, I have seen the
terns recapture their own disgorged fish in the air, before the jaeger could reach
the prize. It looked as though the tern were merely teasing its pursuer.
1098 OCEANIC BIRDS OF SOUTH AMERICA
COMMON TERN
Sterna hirundo hirundo
Sterna hirundo Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 137 (Europe = Sweden).
Names: Wilson’s Tern; in Brazil this and other terns are called ‘‘Trinta Reis.’’ Synonyms of
the specific name include fluviatilis, wilsoni, senegalensis, and macroptera.
Characters: This species, the type of the genus Sterna, is difficult to distinguish, particularly
when in immature plumage, from some of the other medium-sized, black-capped, gray terns. Keys
by Ridgway and others distinguish the species from its nearest relatives by the relatively long
tarsus, lesser amount of forking in the tail, and the vermilion or orange-red coloration of the bill
and feet in adults.
Adults in summer (sexes alike): Pileum and nape, including upper half of lores, uniform black;
rest of upper parts pale neutral gray, the edge of wing, tips of secondaries, lower part of rump,
upper tail coverts, and greater part of tail immaculate pure white; under parts of body uniform
pallid neutral gray to grayish white, fading into white on under and lateral portions of head, the
under tail coverts, axillars, and under wing coverts pure white; outer web of outermost rectrix
gtay, becoming darker terminally, in abrupt contrast with the pure white of inner web, the outer
webs of remaining rectrices (except middle pair) pale gray; outer web of outermost primary blackish
slate, of the other primaries pale silvery gray; inner webs of distal primaries for the most part
white but with a stripe of grayish next to shaft, this stripe abruptly defined on outer five quills
but becoming gradually broader and paler toward the fifth, and extending round tip of web and
returning toward base as a sub-edging, the edge itself white; five inner (proximal) primaries with
inner webs pale silvery gray edged with white; bill vermilion-red, blackish terminally, except on
tomia; inside of mouth orange-vermilion; edges of eyelids black, iris dark brown; legs and feet
orange-vermilion.
Adults in northern-hemisphere winter: Similar to summer adults, but forehead, crown, and
anterior part of lores white, the crown intermixed with black; only the occiput and nape uniform
black; under parts pure white (Ridgway, 1919, 494).
Measurements of 12 specimens of both sexes from Bahia, Brazil, and the east coast of Patagonia
agree well with Ridgway’s figures for 32 specimens from North America and Europe, and are as
follows: wing, 261-267 (264.5); tail, 123-142 (132.5); exposed culmen, 34.4-38.2 (36.3); tarsus,
18.3-19.6 (18.9); middle toe and claw, 24.7-26 (25.3) mm.
Young: Orbital region, occiput, and nape black; crown mixed black and grayish white; fore-
head, loral region, sides of head (below orbital region), entire under parts, upper tail coverts,
inner webs of rectrices, and tips of secondaries, white; upper parts (except as described) pale gray,
the scapulars, interscapulars, and tertials tipped with pale buff and marked with a subterminal
lunule of dusky brown or grayish brown; anterior lesser wing coverts dusky, forming a broad bar
across anterior portion of wing; primaries much as in adults, but darker; larger wing coverts pale
gtay, indistinctly edged with white; outer webs of rectrices grayish, much darker on outermost
pair; bill dusky brownish, the mandible paler and more reddish basally; legs and feet pale yellowish
in dried skins (flesh color in life ?) (Ridgway, 1919, 494).
Distribution: Breeds in North America, Europe, and eastern Asia, from the Canadian provinces,
the British Isles, Scandinavia, and the White Sea, southward locally to the Gulf of Mexico, the
Florida Keys, Bahamas, islands off the coast of Venezuela (breeding?), the Azores, Madeira,
Canary Islands, and northern Africa. Winters from Florida and the coast of Mexico, southward
through the Caribbean, and the tropical Pacific as far as Ecuador, and along the Atlantic coast of
South America to the latitude of the Falkland Islands and the Strait of Magellan.
Although the Common Tern winters in the Caribbean Sea, and northward
throughout the West Indies as far as the southern coast of the United States,
certain examples of the species make far more extensive migrations into the
southern hemisphere than has hitherto been realized.
COMMON TERN 1099
Brazilian records are not uncommon, and it is therefore by no means sur-
prising that Mr. Beck should have found this species over the ocean off Bahia,
where he collected twenty-five or more specimens between April 15 and June 30,
1916. All of these have more or less white on the forehead, although a few
with the pileum practically all black were taken at the end of April. According
to Witherby (1924, 709) and Forbush (1928, 108), the spring pre-nuptial moult
of the Common Tern is a protracted process in the species as a whole, taking
place between February and June. A number of Mr. Beck's Bahia specimens
are apparently yearling birds, with dark epaulettes at the bend of the wing,
and relatively small bills. The bills of all, young and old, are described as
brownish, more or less flesh-colored toward the base of the mandible, and
yellowish at the extreme tip. The feet were reddish.
During October, 1914, and September and October, 1915, Mr. Beck col-
lected a number of Common Terns which represent a great extension of known
range for this species, the localities lying between the coast of the Province of
Buenos Aires, the Falkland Islands, and southern Patagonia. The specimens
deserve listing with their catalogue numbers in the Brewster-Sanford Collection.
4768—female, Mar del Plata, Argentina, October 27, 1914.
4245 and 4248—2 females, latitude 51° S., longitude 68° W., September 10,
1915. The locality is off the coast of Patagonia, between the Strait of Magellan
and Puerto Santa Cruz.
4246—male, latitude 48° 27’ S., longitude 65° 36’ W., September 15, 1915.
This station is a little south of Puerto Deseado.
4247—female, latitude 51° 37’ S., longitude 66° 20’ W., October 1, 1915.
Several, if not all, of these Patagonian specimens are birds of the year, with
dusky bills and reddish legs and feet.
During Dr. Chapman's investigations in the Gulf of Guayaquil, Ecuador,
adults of this tern, with the sexual organs not enlarged, were taken on Novem-
ber 1 and July 20. Chapman (1926, 186) subsequently wrote of the latter:
This species has not before been recorded from Ecuador, and although it is said to have bred
on Aruba and Bonaire Is., off the coast of Venezuela (Bent, Bull. No. 113, U. S. Nat. Mus.), I
believe that these July Ecuadorian specimens, like the northern breeding shore-birds we found
there in July, are barren birds which have lacked the physiological impulse to migrate.
Since it is doubtful whether the Common Tern nests anywhere within the
South American region, I have omitted the descriptions of the eggs and youngest
stages.
ARCTIC TERN
Sterna paradisaea
Sterna paradisaea Pontoppidan, 1763, Danske Atlas, 1, p. 622 (no type locality = Christiansoé, Denmark).
Names: In the ornithological literature this tern has been listed under many specific names,
including hirundo, macrura, arctica, argentata, brachytarsa, brachypus, longipennis, and portlandica.
Characters: In comparison with other terns of approximately the same size that enter the South
American region, the bill is short, slender, and acute; tarsus short (13.5-17 mm. ); feet very small;
tail forked for usually more than 102 mm., when the rectrices are full grown.
Adults in summer (sexes alike): Pileum and nape, including upper two-thirds of lores, uniform
1100 OCEANIC BIRDS OF SOUTH AMERICA
deep black; rest of upper parts mostly plain light gray (between light and pale neutral gray), the
tips of secondaries and tertials, upper tail coverts, and greater part of tail (including whole of
inner webs) white; elongated lateral rectrix with outer web deep gray, growing darker terminally,
in strong and abrupt contrast with pure white of inner web, the outer web of next rectrix pale
gray; outermost primary with outer web dark gray or slate color; inner webs of all the primaries
mostly white, with a stripe of silvery gray next to shaft, this gray stripe growing gradually wider
toward inner primaries, on which it extends across tip of inner web and runs anteriorly near edge
for a greater or less distance, the three or four innermost primaries, however, with inner webs
light silvery gray edged with white; under tail coverts, axillars, and under wing coverts immaculate
pure white; rest of under parts plain light gray (pale neutral gray, slightly paler than color of
upper parts), fading into still paler gray on throat and chin, and into white on sides of head, next
to black of pileum and lores; bill carmine or nopal-red, usually tipped with blackish; iris dark
brown; legs and feet intense red.
Adults in northern-hemisphere winter: Similar to summer adults, but forehead, crown, and
anterior portion of lores white, the crown streaked with black, only the occiput, nape, and pos-
terior portion of lores uniform black; under parts white, sometimes slightly tinged with gray
(Ridgway, 1919, 499).
Measurements based upon 17 specimens taken off the coasts of Peru and Chile and at Mar del
Plata, Argentina, substantially agree with the published data for North American and European
examples, except that the wings and tails, owing to the state of the plumage, average considerably
shorter. They are as follows:
9 males: wing, 245-264 (254.1); tail, 138-145 (142.3); exposed culmen, 29.8-33.2 (31.6);
tarsus, 14.6-16.8 (15.7); middle toe and claw, 20.5-23.2 (22.1) mm.
8 females: wing, 246-268 (254.9); tail, 136-153 (145); exposed culmen, 29-31.6 (30.2); tarsus,
15-16 (15.5); middle toe and claw, 22-23.3 (22.6) mm.
Young in first winter plumage: Very similar to winter adult but with juvenal wings and tail.
Young in juvenal plumage: Like juvenal Wilson's Tern, but rump and tail coverts white without
gray tinge and tail with more white; forehead and crown grayish, latter mottled with black which
increases over ears and on hind head to practically clear black; back and wings ‘‘deep gull-gray,”"
feathers of back, scapulars and wing coverts edged pale buffy, each with subterminal dusky band
and fine dusky sprinkling; markings most conspicuous on scapulars; tertials, secondaries and inner
primaries edged broadly white; considerable dusky and some pale buff near ends of tail feathers;
below white, washed pale brownish on sides, throat, and breast; feet reddish orange; juvenal
plumage worn apparently until birds begin to migrate in September, but probably partially moulted
in autumn to produce first winter plumage (Forbush, 1928, 116).
Distribution: Breeds in circumpolar arctic lands and southward to the British Isles, Baltic
coasts, Massachusetts, British Columbia, and the Aleutian and Commander Islands. South in
winter through the Atlantic and Pacific Oceans, along both coasts of South America to southern
Argentina and Chile, and sometimes to waters beyond the antarctic circle.
The Brewster-Sanford Expedition has thrown much light upon the winter
range of the Arctic Tern. The previous slight claim that this species has had
to a place in the Chilean avifauna is indicated by the investigations of Hellmayr
(1932, 406), who came to the conclusion that there were but two rather unsatis-
factory records, one being of an adult taken at Valdivia, and the other Mac-
Farlane’s (1887, 203) report of a specimen found exhausted on shipboard in
the Bay of Arica, on October 4, 1883. The latter, however, is still preserved in
the British Museum.
Beck's laconic notebook teems with references to Arctic Terns, seen at dis-
tances up to 300 kilometers from the coast of central Peru, during his offshore
cruise of June, 1913. On June 6, 9, 12, 13, 16, 21, 23, and 27, he logged these
migrants repeatedly in the latitudes of Huacho, Ancén, Callao, Cafiete, and
COMMON TERN 1101
Chilca, at points within sight of the continent as well as at distances of three
or four days’ sail to westward. He speaks of the terns as passing singly, in
groups of six or seven, or as ‘‘common.’’ On June 9, 16, and 26, he collected a
number of specimens at oceanic positions between 30 and 80 kilometers from
the coast.
Later in the same year, while on the voyage from Valparaiso to the Juan
Fernandez Islands, Beck once again encountered Arctic Terns in considerable
numbers, and collected specimens between Valparaiso harbor and a point about
175 kilometers offshore on November 4, 14, 19, and December 3.
The majority of these Pacific coast specimens appear to be young birds, but
several are adults in winter plumage or in worn breeding plumage. One male
taken at Valparaiso on November 14 retains an entirely black pileum and a
pronouncedly gray ventral surface, although its quills are exceedingly worn.
A few of the other Chilean examples also show a considerable residuum of the
summer plumage. Most of the rest from both Peru and Chile are in typical
winter plumage, with white foreheads and white ventral surfaces, but a single
female shot off Cafiete, Peru, on June 26, is in the condition of assuming nuptial
dress, with black feathers replacing the white ones on the head, gray sprinkled
throughout the breast and belly, and new quills appearing in the wings and
tail. Among the November and December specimens, the bills were blackish,
the feet dark reddish. In the June birds taken off the Peruvian coast, the bills
were in various transitional stages between dark and red.
On the Atlantic side of the continent, Beck collected a single male Arctic
Tern off Mar del Plata, Argentina, on October 21, 1914. On the same day he
saw others, all working southward, and about a week earlier he had noted the
presence of hundreds, presumably of this same species. Another American
Museum specimen from the South Atlantic is a female shot by myself on Novem-
ber 9, 1912, in latitude 36° 46’ S., longitude 46° 29’ W. This position is far out
on the ocean, but is almost due east of the estuary of the Rio de la Plata.
Paessler (1913, 43) has recorded Arctic Terns on the course between the Strait
of Magellan and Buenos Aires during July, but he does not indicate that speci-
mens were obtained to certify the identification, while the season suggests a far
greater likelihood of migrant Antarctic Terns (Sterna vittata), which he could
have hardly distinguished in the field from Sterna paradisaea.
This brings me to a consideration of the legend which may yet prove to be
a far-reaching ornithological illusion, namely, that the Arctic Tern on its
annual migration regularly crosses the antarctic circle, enters the pack-ice zone,
and attains latitudes as high as 74° S. The currently accepted version of this mi-
gration is succinctly summarized by Forbush (1925, 117) in the following words:
The Arctic Tern is one of the most remarkable birds of the world. It is the long-distance
champion of avian migration. It nests at least as far north as the most northern Eskimos live,
while in winter its tireless pinions beat along the distant shores of unexplored lands of the Antarctic
continent. It sees more hours of daylight and of sunlight than any other creature on earth. On the
arrival of the species at its northernmost nesting-site the midnight sun is shining and it never sets
during the tern’s stay; while for two months of its Antarctic sojourn the bird sees no sunset. For
about eight months of the year it has twenty-four hours of daylight, and during the other four
1102 OCEANIC BIRDS OF SOUTH AMERICA
months more daylight than darkness. Says W. Eagle Clarke: “It has the most extensive latitu-
dinal range to be found among vertebrate animals.”’
According to Professor Cooke the Arctic Tern makes a round trip of 22,000 miles between its
farthest north and farthest south, and he says that no man knows its pathway on the journey.
When it disappears from New England, it seems to be lost in the vast immensity of the Atlantic;
but within about 70 days its flocks are seen in the Antarctic Ocean.
A footnote accompanying Forbush’s account refers to Cooke’s (1915, 10)
paper on bird migration, from which he had, indeed, drawn most of his infor-
mation. But Cooke’s report, with the much-republished
chart showing the summer and winter ranges of the Arctic
Tern—at opposite ends of the earth—is entirely undocu-
mented, and so the subject becomes more and more elusive. It
is not without significance, perhaps, that the area in Weddell
Sea, marked as the northern-hemisphere winter range of para-
disaea, is incidentally the southern-summer or breeding range
of vittata.
There are, as a matter of fact, examples of the Arctic
Tern from relatively high southern latitudes. Two such, in
the British Museum, are said to have been taken in latitude
66° S., longitude 157° W. (off Ross Sea), during March.
Others, now in Edinburgh, were collected by the ‘Scotia’
party in Weddell Sea, across the antarctic continent from
the former locality. Two of the latter I have had the privi-
lege of examining, through the courtesy of the authorities
at the Royal Scottish Museum, and they prove, indeed, to
be Arctic Terns, as previously reported in the literature.
One of these (No. 269, 2) is a bird in excellent plumage
and with an all-black pileum, collected in latitude 68° 32’
S., longitude 12° 49’ W., on March 23, 1904. The second
Fic. 80. Outer-
most rectrix of St
ssihcta perp (No. 4, @) has the forehead, lores, and a good part of the
and Sterna para~ ctown white, with a few blackish speckles caudad; it is in
disaea. Inthe latter the midst of quill moult, the wing-length being only 216
speciestheoutervane mi|limeters. It was captured in latitude 64° 38’ S., longitude
Soe maak 35° 13’ W., on February 25, 1904. Both localities are in the
narrower and more Outer part of Weddell Sea, one of them being not very far to
attenuated. southeastward of the South Orkneys.
These two specimens agree in appearance and dimensions
with comparable Arctic Terns from the northern hemisphere, and differ from
the resident terns of West Antarctica (Sterna vittata) in their short tarsi and
in their narrow, gradually attenuated long rectrices, the dark outer webs of
which form a pronounced contrast with the white inner webs. Furthermore,
the sharply defined white inner edgings of their inner primaries are unlike the
condition in vittata.
Thus the presence of Arctic Terns in Weddell Sea has been definitely estab-
lished by the activities of the ‘Scotia’ naturalists. It does not follow, however,
ARCTIC TERN 1103
that all of the field notes credited to this species actually apply to it. Clarke
(1913, 268) testifies, in brief, that certain terns collected in Weddell Sea, during
the ‘Scotia’ cruise, were identified as Arctic Terns. Birds assumed to be of the
same species were logged “‘by thousands"’ on March 5, 1904, in latitude 72° 31’
S., and others were seen a few days later off Coats Land, latitude 74° 1’ S.,
longitude 22° W. Here they were observed in company with skuas and Antarctic
and Snowy Petrels, while the ‘Scotia’ was locked in the pack. Clarke adds
the comments that the tern observed by the Scottish naturalists certainly does
not breed around Weddell Sea, ‘‘nor is any other tern, so far as we know, a
native of the antarctic continent.’’ Neither of these latter statements has stood
the test of time, for the French Expedition has shown that Sterna vittata nests
abundantly on coasts just to westward which, although insular, are antarctic
and closely connected with the continent. Furthermore, there is now abundant
evidence that a native tern does breed on other antarctic continental shores.
In order to trace the tradition of the Arctic Tern in many parts of the south
polar seas still further toward its source, we must go back to the cruises of the
‘Gauss’ and the ‘Valdivia,’ and to the pertinent ornithological reports of
Reichenow (1904, 350) and Vanh6ffen (1901, 321; 1905, 507). Reichenow states
that the Arctic Tern was encountered by the German Expedition southward
to the Wilkes Land coast, whither the birds had probably been driven by
storms! In another paper of the same year (1904, 47), however, he described
from the Gaussberg, in latitude 66° S., longitude 91° E., on the coast of the
antarctic continent, a supposed resident race of the Arctic Tern, to which he
gave the subspecific name antistropha. The description is very sketchy but, so
far as it goes, fits the characteristics of the widely distributed Antarctic Tern
(Sterna vittata), which appears to be, indeed, so closely allied to Sterna para-
disaea that one may conceivably have been originally derived from the other.
The fact that Reichenow also lists antarctic eggs of this bird clinches the
matter of its identity with véttata rather than with paradisaea.
It is true that on the same page with the description of his supposed *‘antarc-
tic subspecies’’ of paradisaea, Reichenow likewise described as new the small
form of Sterna vittata confined to the island of South Georgia. He compared his
South Georgia specimens, however, not with topotypes of Sterna vittata from
Kerguelen Island, but with examples of this species from West Antarctica.
Without having examined Reichenow’s terns from the Gaussberg region, I can,
of course, come to no final taxonomic conclusion. It is perfectly patent, how-
ever, that his ‘'Sterna macrura antistropha’’ is in reality Sterna vittata, which will
probably prove to be of circumpolar distribution along all suitable shores of
the antarctic continent.
By the same token, I infer that a good proportion of the extreme southern
records for the Arctic Tern are likewise based upon Sterna vittata, and that birds
of the latter species have been quite generally masquerading in the literature
under an incorrect name. Such a supposition is strengthened by Vanhdéffen’s
(1901, 321) statement that the supposedly antarctic representatives of Sterna
paradisaea have not much endurance in the face of the south polar gales, and
1104 OCEANIC BIRDS OF SOUTH AMERICA
do not go far from shore! On one December day, he continues, an example
completely exhausted, and with an empty stomach, fell on board the ‘Gauss.’
Such testimony hardly fits the reputation of the tireless flier as justly described
above by Forbush. Additional notes upon this matter will be found in the
biography of the Antarctic Tern.
Regardless of the ultimate resolution of the doubts expressed, the Arctic
Tern does penetrate southward as far as the Antarctic Zone of surface water,
and certain facts about its migration route have recently been learned by Austin
(1928, 121), Wynne-Edwards (1935, 324), and others. The former presents
convincing data to indicate that the Arctic Terns of North America first migrate
eastward across the North Atlantic, before turning southward toward their
winter range. The observations are based in part upon banding recoveries, and
in part upon birds observed and collected during late August in the North
Atlantic, along the 5lst parallel. Austin also writes as follows with reference
to the subsequent and more problematical stage of the migration:
Our knowledge of the winter range of the species is more hazy and indefinite as it lies for the
most part in seas that are comparatively unfrequented by man. It is usually given as those waters
lying between Brazil and Argentina and West Africa, and south to some undetermined point below
the Antarctic Circle. The Pacific migrants seem to winter off the west of South America, and it is
possible that the two flights may meet somewhere south of the Horn, but concerning this there
are practically no data.
Wynne-Edwards was so fortunate as to witness a definite and prolonged
movement of these terns from west to east, while on a trans-Atlantic voyage
in August-September. His general comments (326) are of great interest:
At sea terns travel singly or in small parties up to about a dozen or occasionally twenty to-
gether. In clear weather they fly between one and five hundred feet from the surface, but when
beating to windward they often keep close to the wave crests. They are so light that in a breeze
they cannot keep a straight course, and even in a calm they often change direction and circle round
at frequent intervals. There is no indication of that intent arrowlike flight of shore birds such as
the Golden Plover, seen at sea, which travel unwaveringly like a bee or a migrant hummingbird,
as if they were racing the devil himself. Terns are like their inevitable companions the jaegers
and take their journey easily. All the same, they stop to feed only on the rarest occasions (once
seen), and never by any chance settle on the water. They seem to dislike swimming at all times,
. They often rest, however, on floating wreckage, and it is a common sight in mid-ocean to
see a tern holding a precarious foothold on some jettisoned spar or wooden case, or even on a gaso-
line can. I have seen terns so resting sixteen times, . . . But never did I detect a single migrant
sitting on the water.
The use of flotsam by terns I have myself witnessed several times on the
high sea. On the morning of December 4, 1924, just off the Gulf of Panama,
but out of sight of land, the distant semblance of a boat full of men almost
caused the captain of the steamer on which I was travelling to turn off his
course in order to effect a rescue. The objects proved to be terns crowded along
a small log, but for a long while they were puzzling, even when viewed through
glasses. When they raised their wings, they looked extraordinarily like cast-
aways waving their shirts.
Wynne-Edwards, in concluding his observations on the Arctic Tern (328),
ARCTIC TERN 1105
boldly champions the much-decried ‘‘sense of direction’’ in trenchant words
which have a bearing upon many of the species of birds discussed in this book:
Any observations of birds in the act of migrating across great tracts of water must be taken into
consideration by those who would solve the problem of orientation. It seems not insignificant that
these terns, crossing such an unusually wide expanse of ocean, where there is not a vestige of a
landmark of any description for two thousand miles, where the wind sometimes changes direction
in a few hours and the sky is often completely overcast for days at a time, pursue such a careless
and irregular path. One might expect them to be more intent on the matter in hand for fear they
were diverted from their course and got lost. This is no place for a discussion of this intricate
question, which would in any case be profitless at the present time, but it may be observed that
their sense of direction must be absolute, like that of the compass, without reference to objects
they have left behind; and that the faculties by which it is regulated can be called into play at
any time in the course of their flight.
ANTARCTIC TERN
Sterna vittata, and its subspecies
One of the interesting results of my work with the Museum's incomparable
series of sea birds from American Antarctica is the discovery that the tern of
the Antarctic Archipelago has been persistently misidentified. In most of the
recent and current literature, the South American Tern (Sterna hirundinacea) is
recorded as a resident of the South Orkney and South Shetland Islands, etc.
No examples have appeared in our collections from these regions but, on the
other hand, the Antarctic Tern (Sterna vittata) proves to be a common and
widely distributed bird throughout most of the islands of the Scotia Arc.
It appears that the range of Airundinacea is much more restricted than has been
generally believed; the species is, in fact, confined to the continental littoral,
its most distant outpost being the Falkland Islands. At no point does it pass
poleward of the Sub-Antarctic Zone of surface water, and all of the records
listed under its name for the lands to southward of Cape Horn refer, in reality,
to Sterna vittata.
The latter antarctic species, represented by several local geographic races,
is much in need of systematic revision. The necessary specimens for such a
study are not at present available to me, but I can at least describe the two
forms which are found, respectively, at the South Shetlands and at South
Georgia.
Among the authorities who have repeatedly reported the presence of Sterna
hirundinacea at the South Shetlands and other islands of the Antarctic Zone is
that keen student of birds of the far south, Mr. A. G. Bennett. At my request,
Mr. Bennett has kindly sent to the American Museum four adult breeding males
of the resident tern of Deception Island. These were collected on December 1,
1921. The collector had labeled them *‘hirundinacea,’’ but they all prove to be
examples of vittata!
While this discovery will make necessary a considerable emendation of
references in the literature, it should be noted that Gain (1914, 90) long since
came to the correct conclusion regarding the identity of the breeding terns in
West Antarctica. His careful descriptions and measurements, as well as the
1106 OCEANIC BIRDS OF SOUTH AMERICA
series of plumages illustrated in Plate 11 of his volume, leave no doubt as to
the matter.
Reichenow (1904, 47), when describing the resident tern of South Georgia
as Sterna vittata georgiae, must also have been cognizant of the presence of the
same species in the ‘‘Graham Land”’ region, because he compared his type
specimen from South Georgia with examples from West Antarctica, although
the type locality of the typical race is not in that part of the world at all, but
rather at Kerguelen Island in the southern Indian Ocean. By way of illustrating
the present unsatisfactory state of our knowledge regarding the forms and
distribution of Sterna vittata, I quote below the citations and ranges of all the
subspecies which Peters (1934, 333) has seen fit to recognize. The ranges, as
here stated, are in part erroneous, particularly that ascribed to the typical race:
1. Sterna vittata vittata Gmelin.
Sterna vittata Gmelin, Syst. Nat., 1, pt. 2, 1789, p. 609. C‘Insula Nativitatis Christi’? =
Christmas Harbor, Kerguelen Island).
Breeds on Ascension, St. Helena, Tristan da Cunha, Gough, St. Paul, Amsterdam and Kerguelen
Islands, ranging to the coasts of South Africa (largely erroneous).
2. Sterna vittata georgiae Reichenow.
Sterna vittata georgiae Reichenow, Orn. Monatsb., 12, 1904, p. 47 (South Georgia).
Breeds on South Georgia and the South Orkneys, ranging to the east coast of southern South
America (partly erroneous).
3. Sterna vittata bethunei Buller.
Sterna bethunei ‘’Travers’’ Buller, Trans. and Proc. New Zealand Inst., 28, 1895 (1896), p. 348
(Bounty Islands).
Sterna vittata bollonsi Mathews and Iredale, Ibis, 1913, p. 244 (Sub-antarctic Islands of New
Zealand).
Breeds on the Bounty Islands, occurs and probably breeds on Snares, Antipodes, Auckland,
Campbell and Macquarie Islands.
Only the first two of these three subspecies concern us at present. As will be
seen, the form of West Antarctica is left without a subspecific name unless it
should prove to be identical with the resident bird of Kerguelen Island, which
seems unlikely. Furthermore, as I have already shown in Part I (p. 154), no
form of Sterna vittata has ever occurred either at St. Helena or Ascension, and
the records from these islands are due to error. I may add that the form in-
habiting Tristan da Cunha is not likely to be identical with that of Kerguelen,
and that the evidence for the occurrence of-the South Georgian subspecies at
the South Orkney Islands (Dabbene, 1918, 138) is highly inconclusive.
Let us consider first the resident terns of West Antarctica. The four examples
collected by Bennett at Deception Island closely resemble specimens of the
South Georgian race, except for their considerably larger size. The measure-
ments of the four males are as follows: length in the flesh, average, 377; wing,
278-285 (280.7); tail, 122.9-154 (141.3); exposed culmen, 35-37.1 (36.4); tarsus,
18-19.1 (18.6); middle toe and claw, 23-24.5 (23.7) millimeters. It should be
noted how closely these figures, particularly the length of bill and tarsus, agree
with specimens from Booth-Wandel and Petermann Islands as recorded on
page 88 of the French Antarctic Expedition report. Measurements of South
Georgia birds are strikingly smaller, as shown by the following averages based
ANTARCTIC TERN 1107
upon ten males: wing, 253.7; tail, 129.5; exposed culmen, 30.9; tarsus, 16.9;
middle toe and claw, 21.4 millimeters.
Our four Deception Island specimens are characteristically of a darker gray
than any examples of Sterna hirundinacea, the tern with which they have been
so often confused. The difference in shade is particularly noticeable on the
ventral surface. They are also definitely smaller in certain measurements, and
have particularly tiny feet in comparison with their other appendages. The
average lengths of the tarsus and middle toe in 17 males of Sterna hirundinacea
from South America are 21.6 and 27 millimeters, respectively, as against 18.6
and 23.7 millimeters for the same units in the four males of Sterna vittata from
Deception Island.
Coues long ago pointed out the close apparent relationship between vittata
and the Arctic Tern, stating that the former might be regarded as a representa-
tive of Sterna paradisaea (Kidder, 1875, 17). It is, of course, quite possible that
the extensive migratory flights of the Arctic Tern ultimately led to the develop-
ment of a form confined to the far south, although there are no exact data relat-
ing to the spread of species by such means.
In 1904 Reichenow described from the Gaussberg, latitude 66° S., longitude
91° E., a supposed subspecies of the Arctic Tern which he designated Sterna
macrura antistropha. The type locality is on the shores of the antarctic continent,
a long distance southward and a little eastward of Heard and Kerguelen Islands.
Although this race has been synonymized with Sterna paradisaea by Peters
(1934, 333), I believe that it is almost certainly a resident race of Sterna vittata.
Its head was subsequently figured in color (Reichenow, 1908, 463), in connection
with which the describer also stated that four eggs and several young of the
species were collected at Gaussberg on February 18, 1903. These facts are
sufficient to prove that antistropha is not synonymous with paradisaea. Further-
more, Gain (1914, 93) writes of an adult specimen from Booth-Wandel Island
in West Antarctica:
Il présente exactement les caractéres que Reichenow a donnés dans sa description du Sterna
antistropha. La figure en couleur qui représente la téte et la patte de cette espéce coincide exactement
avec les caractéres du S. vittata adulte, et nous ne voyons aucune utilité a faire une espéce distincte
des Sternes qui nichent dans les régions glacées antarctiques.
Somewhat later Gain concludes that a short description by Valette (1906,
54) demonstrates that the bird nesting at the South Orkney Islands is not Sterna
hirundinacea, but a member of the same species which occupies South Georgia
and the Antarctic Archipelago, namely Sterna vittata.
It is well known that whereas many specific groups of organisms belonging
to the Sub-Antarctic Zone, or even to the outer latitudes of the true Antarctic,
break up into geographic races corresponding with various segments of the
far south, the forms of plants and animals inhabiting the deep Antarctic, namely
such as occur along the coasts of the antarctic mainland and in adjacent seas,
are usually circumpolar in their ranges (Murphy, 1928, 369). From this it
appears quite possible that the Antarctic Tern described by Reichenow from
Gaussberg, in Kaiser Wilhelm II Land, may turn out to be the same as the form
1108 OCEANIC BIRDS OF SOUTH AMERICA
inhabiting the west antarctic region. If subsequent comparison of specimens
proves the truth of this, the name antistropha may be applicable to a subspecies
of Sterna vittata occupying suitable stretches of coast around the outline of the
whole antarctic continent, as well as the colder outlying islands. For the pres-
ent, I propose no subspecific name for the South Shetland Tern, but will point
out that it exactly resembles the South Georgian Tern except for its much larger
size, as noted above. These two races furnish, by the way, an exact illustration
of Bergmann’s law of the geographic relation between bulk and thermal
economy.
Many records of unidentified terns appear in the literature of south polar
exploration, a recent instance being a note by Wilson of two terns with ‘‘black
heads, white rump and tail, and darkish-grey wings and back,”’ seen between
the Balleny Islands and Oates Land during the cruise of the ‘Terra Nova’ in
March, 1911 (Lowe and Kinnear, 1930, 112). No doubt all such records refer
to this species, and very probably to a single race of the species.
During the voyage of the ‘Pourquoi Pas?,’ the French naturalists encountered
the Antarctic Tern not only at three islands of the South Shetlands, but also all
along the west coast of the Antarctic Archipelago, at the islands of Wiencke,
Doumer, Booth-Wandel, Petermann, Argentina, Berthelot, and Léonie, the
last being inside the antarctic circle. Many examples were also seen along the
border of the pack-ice, as far as latitude 70° S., longitude 120° W.
On September 5 the first returning migrants appeared at Petermann Island,
the last birds reaching this breeding ground by October 22. During early
November the terns prepared their nests, which are merely slight scrapes in
the ground, sometimes decorated with bits of shell from the old hatched-out
eggs of other birds such as Kelp Gulls. The first egg was recorded on November
14. On January 10, in a colony of from 150 to 200 birds near the southern point
of Petermann Island, most of the nests contained either two or three eggs, or
one or two chicks in various stages of growth. The number of eggs is con-
firmed by other observers, and seems remarkable in view of the fact that terns of
the South Georgian race are not known to lay more than one. By February the
chicks at Petermann Island were advanced -in growth, and during March
the nesting sites were abandoned and the young swam about more or less in the
channels and coves. Although they lost their down only gradually, within
three months after hatching they had attained the size of their parents. In
May all of the birds, young and adult, disappeared completely.
Menegaux (1907, 36) records the beginning of nest-building at Booth-
Wandel Island in October. Most of the groups comprised not more than from
six to ten birds which nested on rocks near the shore, close to each other and
often near nesting Kelp Gulls. Either two or three eggs were observed in
each nest.
At the South Orkney Islands, according to Valette (1906, 54), these terns
arrive during October and leave about the end of April, the egg-laying season
extending from late November through January. The slight hollows of the
nests are rarely less than about 12 meters apart, indicating relatively large
ANTARCTIC TERN 1109
territory requirements, and they extend from sea level to an altitude of 200
meters or thereabouts. The fondness of the birds for nesting in the terminal
moraines of glaciers (Bennett, 1920, 25) is reminiscent of the habits of their
close relatives at South Georgia. Shells and pebbles are often gathered and
placed around the nest by the incubating bird. Valette records the temperature
of nesting terns as 42.2° C., and Gain as 39.4° C., the discrepancy being unsatis-
factorily great.
The observations of the Scottish naturalists on this tern at the South Orkney
Islands are reported upon by Clarke under the erroneous name Sterna hirundinacea.
The last bird of the autumn was seen at Saddle Island on March 25, 1903, and
the first spring migrant was observed on October 21, though it is possible that
some had been heard two or three days earlier. Clarke's (1913, 241) account
continues as follows:
The nests were mere hollows, lined with a few small fragments of stone, on the tops of small
rocks, or on raised beaches and small screes, and were always quite close to the shore. The nests
in the colonies were placed fairly close together, and often in proximity to those of Larus domini-
canus. When not surprised on their nests, these birds usually betrayed the whereabouts of their
treasures by hovering over them and screeching loudly.
The eggs were one or two in number. The first were found on November 14th, and from that
date onwards they were observed until January 15th. In 1904 Mr. Mossman records the first eggs
observed on November 27th.
The earliest chicks were obtained on December 25th, and by ey 7th young were noted
as having lost all their down.
A few adult specimens and a chick are included in the collections; also a number of eggs, averag-
ing 4.73 cm. by 3.34 cm.
Further notes on the eggs are given on p. 1110 in comparison with those of
the South Georgian subspecies.
The food of the Antarctic Tern is known to include small fishes and many
sorts of crustaceans. The commonest of the antarctic opossum-shrimps
(Euphausia superba), which is the principal food of whales and of many sea
birds, is known to make up a large part of the tern’s diet both at the South
Orkneys and South Shetlands (Valette, 1906, 54; Gain, 1914, 95). They obtain
their food both by diving and by swooping down to seize the prey at the
surface without submerging themselves.
SOUTH GEORGIAN TERN
Sterna vittata georgiae
Sterna vittata georgiae Reichenow, 1904, Orn. Monatsb., 12, p. 47 (South Georgia).
Names: Wreathed Tern; Kingbird, a name applied by the sealers and whalemen at Tristan da
Cunha, has been given to the representatives of this species at various pan-antarctic islands.
Characters: Closely similar to the Arctic Tern (Sterna paradisaea), differing chiefly in the
following particulars: adults in nuptial plumage of a slightly darker and less pearly gray, which
approaches pale mouse-gray or even smoky gray (the winter plumage is lighter); tail shorter and
less deeply forked, the outer rectrices very much broader basally than those of paradisaea, and
tapering more abruptly toward the tip; furthermore, the outer web of the outermost rectrix is not
so dark as to make a pronounced contrast with the inner web—it is, on the contrary, such a pale
gray that the entire tail looks practically white; the tarsus, moreover, is slightly longer than in
1110 OCEANIC BIRDS OF SOUTH AMERICA
paradisaea, all other dimensions, except those of the tail, being practically identical in the two
species. The winter plumage also parallels that of the Arctic Tern. Iris brown; bill red with a
black tip; feet dull red, tarsus lighter.
9 males: wing, 246-261 (254); tail, 123.7-137.5 (129.5); fork of tail averaging about 70;
exposed culmen, 30-31.8 (30.9); bill from gape averaging about 42.2; tarsus, 16.2-17.8 (16.9);
middle toe and claw, 20.1-22.8 (21.5) mm.
5 females: wing, 255-266 (261); tail, 117-141 (129.5); exposed culmen, 28.7-30.5 (29.5);
tarsus, 15.9-17.5 (16.6); middle toe and claw, 21.2-23.9 (22) mm.
Adults of the Deception Island race exactly resemble South Georgia birds except for their
notably greater size, as shown by the measurements on pp. 1106, 1107.
In the downy and juvenal plumages the South Georgian Tern resembles the Arctic Tern much
less than in the mature stage, and exhibits rather an affinity with Sterna hirundinacea. Both the
latter species and vittata retain the presumably primitive barred pattern much longer than does
paradisaea. From the speckled buffy down in which it hatches, the young of vittata comes into a
barred and streaked buff and blackish plumage, with the white of the ventral surface heavily
overlaid with specklings. The whole cast of the dorsal surface is then somewhat *‘golden,”’ like
the winter plumage of a Black-bellied Plover (Charadrius). The buffy bars fade rapidly, so that by
the stage of flight, when gray feathers are intermingled over the back, the general effect of the
remaining bars is black and white, but throat and breast are still heavily speckled.
Eggs from South Georgia have a ground color varying between light yellowish olive and dull
citrine. This is overlaid with spots and blotches of brown, some of the markings being as rich as
clove-brown. Some eggs are rather evenly marked; others have a solid cap of color at the larger
end, while still others are more or less wreathed with spots at this end. Two taken at the Bay
of Isles in January measure 44.4 x 31.2 and 44.5 x 31.4 mm. Lonnberg records a third measuring
48.5 x 30.5 mm.
It is curious that the larger race of vittata inhabiting the Antarctic Archipelago has eggs which
are no larger than those of the South Georgian subspecies. Examples of ten collected at Booth-
Wandel, Petermann, and Deception Islands between November and January measure 43 x 34,
47.5 x 32, 45 x 31, and 48 x 35 mm. (Gain, 1914, 96). The average length of ten is 45.45, as
against 45.6 for three eggs from South Georgia. The weights of four eggs from Petermann Island
vary from 27-35 and average 30.2 grams.
A number of eggs from South Orkney Islands, as recorded by Clarke (1913, 241), average 47.3
x 33.4 mm.
Distribution: South Georgia, where it is probably endemic and sedentary. Evidence for the
presence of this subspecies at the South Orkneys (Dabbene, 1918, 138) is inconclusive.
My first acquaintance with this attractive little tern came on November 24,
1912, while we were idling in the brig ‘Daisy’ along the rugged coast of South
Georgia, driven before eddying and uncertain winds. The terns were feeding
here and there over the open ocean, but their numbers increased greatly as we
entered Cumberland Bay. After this I saw the birds daily along various parts
of the northeasterly coast of the island, until the departure of our vessel in the
middle of March. They were observed over the coastal waters and in all of the
bays, as well as up the valleys and into the heart of the mountains at altitudes
as high as 300 to 400 meters. It is not impossible, as Will (1884, 140) suggests,
that they may feed in part among the upland swamps of South Georgia, using
their sharp bills to extract tiny organisms from the moss. Undoubtedly, how-
ever, they obtain the greater part of their prey by diving into sea water kept
quiet by the gently heaving kelp; in such places I constantly saw the terns not
only during the hours of daylight but also continuing to plunge by the light of
the moon, well into the night.
SOUTH GEORGIAN TERN 1111
Offshore on the whaling banks, at a distance of 25 or more kilometers from
the coast, I never saw a single example of the tern among the millions of petrels,
albatrosses, penguins, etc., that were always about. For such reasons it seems
probable that the tern is sedentary and not given to long flights across the ocean
either in search of food or in migration. Like other members of its species, it
avoids contests with the raging gales of the far south. According to Szielasko
(1907, 597), the South Georgian Terns collect in massed flocks on the beaches
at the first gusts of blizzards and williwaws, each bird scraping its way into
the sand by squatting and turning about until it has formed a sheltering dugout.
Evidence in the literature is not quite conclusive as to whether all of the
terns remain at South Georgia throughout the winter months, but I am inclined
to believe that they do, and there are numerous records of their presence between
April and October. As Lénnberg (1906, 64) notes, they keep to the littoral
during the winter, the land being then deeply buried under snow. I do not
know the authority for Peters’s (1934, 333) statement that some examples range
to the east coast of South America. The breeding bird of the South Shetlands
belongs, as I have shown, to a distinct and larger subspecies. When it becomes
possible to compare representatives from the South Sandwich, South Orkney,
and Tristan groups with those from South Georgia, we shall know much more
about relationships and distribution within the species.
The breeding sites of the tern at South Georgia are highly various, some of
them being far up among the hills on steep slopes, or about the shores of tarns,
and others on flats close to sea. At the Bay of Isles, for example, I found the
birds nesting upon sharp chips of stone in the terminal moraine of Grace Glacier,
and also on a steep bank of crumbling shale near the summit of Albatross Island,
about a hundred meters above the sea. In the latter colony, on January 2, I
found eggs laid in the mossy depressions between stones, in some instances with
a few wisps of dried grass by way of nest-lining. The eggs and young examined
here, together with other eggs noted at Cumberland Bay on December 3, show
that a single egg constitutes the full set. This agrees with records made
by members of the German Expedition on Mount Krokisius at Royal Bay. I
have noted above that the larger race of Sterna vittata inhabiting the Ant-
arctic Archipelago lays two or even three eggs, but that these are no larger
than the egg of the South Georgian Tern. There is a suggestion of some sort
of biological compensation in this curious relation between size of egg and
size of clutch.
The breeding season is evidently rather more prolonged than that of most
South Georgian birds. Members of the German Expedition of 1881 observed
the mating of the terns on November 29 (von den Steinen, 1890, 265), and
Szielasko found an egg as early as November 23. Matthews (1929, 582) also
states that the egg is usually laid in the second half of November. I found
numerous eggs after New Year, and von den Steinen reports freshly laid examples
in early February. The skua may be largely responsible for such prolongation
of the nesting season, for it is probable that this enemy occasionally makes
second layings necessary. Furthermore, these terns are by no means averse to
1112 OCEANIC BIRDS OF SOUTH AMERICA
stealing and eating the eggs of their own kind, particularly when a colony of
the birds has been thrown into excitement by the incursion of a skua.
The presence of a breeding group is usually betrayed by the terns themselves,
for they come out of their way to attack an intruder, hovering about with
harsh screams and darting at one’s head. It was in this way that I discovered
the Albatross Island colony referred to above, for I had not expected to find the
birds nesting on this tussock grass-grown islet. There proved to be about
thirty to forty pairs here and, among the pebbles, lichens, and moss, eggs and
tiny chicks were equally difficult to see, for the latter remained quite as motion-
less as the former. I quickly discovered that the best way to find them—and to
avoid stepping upon them—was to withdraw a few paces, whereupon the
solicitous but very unintelligent parents would at once flutter down, still
scolding, to their respective nests. Sometimes, however, a bird would have a
prior and evil interest in another’s nest. Right under my nose I saw several
crack eggs and carry away pink and dripping embryos, before the rightful
parents could prevent such cannibalism. The frequent but unsuccessful attempts
of other terns to express the same unsocial behavior was evidence that the
custom was not novel to them.
Five of the terns’ eggs collected on this date, January 2, were fresh-laid, a
sixth was almost ready to hatch, and I judge that no chick was more than a
few days old. All of the latter remained ‘‘frozen’’ throughout the disturbance.
Matthews (1929, 582) states that very early in life they begin to leave the nests
and to crouch among the stones near-by.
On a moraine behind the beach at the Bay of Isles, I found these terns occupy-
ing more scattered nests, which they were very unwilling to leave while incu-
bating. There seemed to be a definite relation between weather conditions and
the reactions of the birds, because on several occasions when snow was driving
down before a high wind I was able to touch the terns before they would spring
off the egg. The sitters protested, nevertheless, at my proximity with high-
pitched calls which brought their mates to the vicinity, the latter sometimes
poising half curiously, half threateningly, close to my face, or alternately dash-
ing at my head and alighting upon a rock close by, chattering all the while.
Whenever a skua flew near, however, both terns would forget me, and the sitter
would leave the egg to join its mate in pursuit of the more familiar robber. The
skua always demonstrated its ability to outdistance the terns, but the latter
would pursue it for a long way, trying repeatedly to strike it. On February 1
one pair of terns at this locality was faced with the dilemma of dividing its
attention between me, several Kelp Gulls, and two skuas. Their response
showed, however, that they regarded the skua as the worst of the evils, and
me as the least, for they attacked the three species of encroachers in the order
named, devoting all their attention to the skuas and gulls until both had been
driven from the neighborhood, even though I was standing directly over their
nest all the while. By collecting on two occasions terns which I had been watch-
ing closely, I learned that the male is the bolder and more aggressive in the
tactics employed against trespassers.
SOUTH GEORGIAN TERN 1113
By January 11 I saw a number of young terns so far advanced as to be flying
a little, and before the end of the month these became rather abundant. They
joined the flocks of adults over the kelp fields, and could be distinguished not
only by their appearance but also by their note, which is sweet and mellow.
At Possession Bay, on March 8, I saw very large clouds of terns over the
moraines on the west shore of this deep fiord. There were many hundreds
together, perhaps flocking because their breeding season was entirely over.
About this same season I saw also mixed groups of adults and young perching
along the edges of cliffs, from where they would occasionally fly down to pools
in the sluggish kelp.
South Georgian Terns collected by myself, and others obtained by Correia,
show that the plumage is grayest during November and December, before the
strong, even though chary, summer sun has had time to bleach the feathers
acquired by a pre-nuptial moult. Such examples also have the longest tail
quills, and the lightest tone of red in the bill and feet. By April, a post-nuptial
moult of quills and body feathers causes the anterior half of the crown to turn
white, and the ventral surface to become very light gray. The broad white
stripe just under the black cap is then much less conspicuous than during the
breeding season. Young taken as late as July or August still show a trace of the
barred feathering.
I find nothing in my notes to distinguish the call of the South Georgian Tern
from that of related species elsewhere, such as the Arctic Tern. They are very
noisy but probably no more so than most of their kin. Will (1884, 140) records
the ordinary cry as ““Trr Trr Kriah."’ Another common chattering note is like
the rattle of pebbles or the gritting of teeth.
The food of the South Georgian Tern comprises crustaceans, such as eu-
phausians and isopods, as well as tiny fish. During January and February I
frequently saw birds flying from coves to their nesting grounds carrying silvery
fry in their bills. Lénnberg (1906, 64) has identified fish from their stomachs
as the young of Notothenia macrocephala, a species which abounds in the kelp
fields, although full-grown examples are usually to be obtained only toward
the bottom, in depths of 10 to 20 meters or more. I found that the terns were
always willing to quarrel with the petrels for small scraps of blubber tossed
overboard from our anchored brig in the Bay of Isles, and that they would even
flutter about the carcasses of newly killed seals ashore, and pick at both the
fat and the flesh.
TRISTAN DA CUNHA TERN
Sterna vittata, subspecies
Distribution: Tristan da Cunha group, and Gough Island.
A form of the Antarctic Tern, locally known as the Kingbird, is resident at
Gough Island and at all three islands of the Tristan group. Wilkins (1923, 509)
found great numbers of both adults and flying young at Gough during his visit
at the end of May, and he reports that they rested at night on the ledges of
cliffs, as the South Georgian Terns do. Barrow (1910, 275) states that at Tristan
1114 OCEANIC BIRDS OF SOUTH AMERICA
da Cunha the tern is a migrant species, coming back to the island in September
and laying its eggs in November. Flying young have been reported in the middle
of January. Mathews (1932, 45) describes eggs taken during mid-November
at Sandy Point, on the east side of Tristan. Sets of one or two were found on
bare sandy ground, with little or no nest-lining. Six examples averaged 46 x
32 millimeters in dimensions, the largest being 47.5 x 33.
This tern was also collected at Inaccessible Island during the ‘Challenger’
expedition, but I have seen no specimens.
TRUDEAU’S TERN
Sterna trudeaut
Sterna Trudeaui Audubon, 1838, Birds Amer. (folio edit.), 4, pl. 409, fig. 2 (Great Egg Harbor, New Jersey).
Names: In Argentina this species is known as ‘‘Gaviotin,”’ the same name applied to other
medium-sized terns; in Brazil a published name is ‘‘Trinta Reis’’ which is also applied to other
terns. A specimen from Chile has been described under the specific name frobeenii and one from
Uruguay under the name sellovii.
Characters: This species is distinguishable from other terns by its white pileum and nape;
the under parts are pale gray like the back, and the bill yellow with a subterminal band of black.
Adults in summer (sexes alike): General color plain pale gray (nearest lilac-gray), paler (nearly
white) on rump, upper tai] coverts and tail, fading into white on head and upper neck, the primary
coverts and greater part of primaries still paler gray or silvery white, the outer web or outermost
ptimary deeper gray than back, etc., the inner (proximal) primaries with inner webs becoming
dusky toward edge and margined with white; a spot of black immediately in front of eye, and a
less sharply defined post-ocular stripe of the same, occupying upper portion of auricular region;
axillars and under wing coverts and broad tips to secondaries, immaculate white; bill yellow with
a broad subterminal band or area of black; iris dark brown; legs and feet brownish in dried skins
(said to be orange-yellow or dull orange in life) (Ridgway, 1919, 488).
Wetmore (1926, 138) writes of an adult female from Argentina: tip of bill cinnamon-buff,
base between zinc-orange and tawny; band across distal third black; iris Vandyke brown; tarsus
and toes zinc-orange, the scutes clouded with fuscous; nails blackish.
Adults in winter: Similar to summer adults, but stripe on side of head more grayish, especially
the post-ocular portion, and (especially in fresh plumage) the silvery frosting on primaries more
pronounced; bill black, tipped with yellowish (Ridgway, 1919, 489).
14 specimens of both sexes from Argentina and Chile: wing, 250-270 (258.1); tail, 104-140
(116.1); exposed culmen, 38-43 (40.8); tarsus, 23.4-26.7 (25.4); middle toe and claw, 27.5-30.2
(29) mm.
Young: The patch before and the streak behind the eye decidedly larger, and there is an
indication of a grayish crescent on the nape; the crown grayish white, slightly mottled with
brown, as are the feathers of the mantle; tail feathers dark ash-gray with white margins; bill
yellowish brown at the base, the rest blackish, with no yellow at the tip; tarsi and toes yellow
(Ridgway, 1919, 489).
Eggs from the Province of Buenos Aires, Argentina, are described by Gibson (1920, 76) as often
elongate and sometimes pear-shaped, with an olivaceous or yellowish brown color and with spots
and blotches of dark ash-gray, red-brown, dark brown and black, and (under the surface) dull
lilac areas. Three or four constitute a set, the average measurements of eggs in Gibson's series
being 43 x 31 mm. Bent (1921, 228) records a number of sets alleged to have come from San
Ambrosio Island, latitude 26° S., far off the coast of Chile, on December 17, 1907, but, as noted
elsewhere, the locality is almost certainly incorrect. These, he states, are not distinguishable
from certain types of eggs of Sterna hirundo. The ground color varies from Isabella to deep olive-
buff. Some are uniformly spotted or blotched at the larger end. A number of eggs show under-
lying spots of drab or lilac. The measurements of 10 average 41.7 x 30.6 mm. The eggs showing
TRUDEAU'S TERN 1115
the four extremes measure 46.4 x 30.4, 44.7 x 31, 39 x 30.5, and 39.5 x 30mm. If these are actually
eggs of Trudeau's Tern, which is not improbable from their measurements, they are likely to have
come from some mainland locality.
Saunders (1891, 373) has pointed out that the eggs of Sterna trudeaui are somewhat intermediate
in shape and pattern between those of coast-breeding forms of terns and those of the marsh tern
(Hydrochelidon = Chlidonias) group.
Distribution: Breeds on the coast and in the interior of the Province of Buenos Aires, Argentina;
known to occur on the Atlantic coast of South America from Rio de Janeiro to the Strait of Magel-
lan, and along the Chilean coast between Arica and Corral. Accidental in North America.
On the western coast of South America Trudeau's Tern is known only from
a few specimens taken in Chile, one of which has been figured by Philippi
(1902, pl. 47, fig. 2). It is therefore of interest to report that the American
Museum has two adult males taken by Mr. D. S. Bullock at Penco, Bay of
Concepcién, on March 4, 1927, and September 21, 1928. The presence of a
breeding colony at the little waterless and nearly plantless island of San Am-
brosio, as announced by Bent (1921, 228), is open to serious doubt, as noted on
page 261. Bent’s account, which is highly circumstantial, states that at San
Ambrosio in mid-December the nests of this species were found to be mere
hollows without lining, placed in the sand among boulders. The birds proved
to be close sitters, and they perched about so unguardedly after being flushed
from their eggs that one of them was killed by a stone tossed by the collector.
The discovery, if verified, would be an extraordinary one for a species which
seems so thoroughly continental in its usual preferences for fresh water over
salt. However, the ‘Zaca’ expedition saw no trace of Trudeau's Tern at San
Felix and San Ambrosio in February, at which season fledgling young might
have been expected.
In the northern coastal region of Argentina this species has been reported
upon by Durnford (1877, 200), Holland (1890, 428), Gibson (1920, 75), and
Wetmore (1926, 137).
Durnford observed Trudeau's Tern near Flores Island, at the mouth of the
Rio de la Plata, during every season except spring. Holland found them nesting
in a gullery of Larus maculipennis at Estancia Espartilla, Province of Buenos
Aires, early in November. The nests were segregated from those of the gulls,
and were at a corner of a lagoon, among flooded willow stumps, without
sheltering rushes, and surrounded by rather deep water. There were thirty to
forty of them close together, each composed of very wet, green water grass,
and kept above the surface only by the mass of vegetation underneath. There
were three or four eggs in each nest, no two of which seemed to be similar.
Gibson states that Trudeau's Tern is to be found on every interior marsh and
lagoon, as well as along the seacoast, of the Cape San Antonio district in the
Province of Buenos Aires. Inland the species is usually encountered singly or in
pairs, but on the coast large flocks are a daily feature. These birds are bold in
defending their nests, and Gibson on one occasion was struck three times in
rapid succession by the same individual. He found, during long years of ob-
servation, that the beginning of the breeding season varied between October 26
and January 5. Not infrequently the Tern colonies were combined with those
1116 OCEANIC BIRDS OF SOUTH AMERICA
of the Spot-winged Gull, as reported also by Holland. Gibson observed that
Trudeau's Terns perched on wire fences, just as the gulls frequently do. Sucha
habit seemed extraordinary to him in a sea of flooded land, but it matches the
familiar North American experience of seeing terns of several species perching
upon the fine cordage of fish weirs. That Trudeau's Tern should nest in Argen-
tina, “‘generally at the side of a swamp . . . the material always soaking
wet water weeds, and . . . floating in the same,’’ would be enough to cast
doubt upon its breeding in dry sand on the oceanic, semi-arid islet of San
Ambrosio.
Wetmore saw very many Trudeau's Terns, both inland and along the coast
of Argentina and Uruguay, between the months of October and March. During
January they were common at Carrasco, east of Montevideo. This writer's
always enlightening notes are as follows:
Trudeau's tern in flight and general actions is similar to other smooth-headed terns. As the
birds beat back and forth with zigzag flight along shallow channels they darted down at intervals
to secure small fish that appeared in the water within striking distance. When they were not feed-
ing they gathered in close flocks to rest on some sandy beach or point near water. Below Cape San
Antonio parasitic and long-tailed jaegers harried them and made them disgorge. Once or twice
I noted hooded gulls in similar attempts, but in each case the tern with seeming ease eluded its
less agile pursuer.
The call notes of Trudeau's tern are sharp and explosive and suggest in many ways the sounds
emitted by Forster’s tern, a species that the present one suggests strongly in life. A usual call
was a sharp ttk tik tik, changed when birds became angry or excited to a drawn out keh-h-h. As
birds in full plumage approach across the level expanses of the broad marshes or along some open
sea beach they appear plain gray, with light head and a prominent dark mark through the eye.
In winter the undersurface of the body is entirely white. At times they were wary but were enticed
within range by a white bird or a handkerchief waved in the air. Near Lavalle through inquiry
I located a small breeding colony of the gaviotina, as these terns were known locally, where the
birds were associated with gulls, but before I was able to visit it the ternery was raided by boys
who sold the eggs to the local baker for use in preparing cakes (Wetmore, 1926, 137).
At Mar del Plata, in October, 1914, during the course of the Brewster-
Sanford Expedition, Mr. Beck noted and collected a number of Trudeau's Terns.
His journal reports that most of them were seen about ponds and pasture-puddles
back from the coast, rather than over salt water. Their stomachs, furthermore,
contained small fresh-water fishes. All of the specimens from this locality are
in somewhat worn plumage, and are much less gray than a male taken near
Buenos Aires on September 21. The gonads are described as minute, and Beck
believed that not one of the birds had experienced even the beginning of the
physiological changes incident to the breeding season.
ROSEATE TERN
Sterna dougalli dougalli
Sterna Dougalli Montagu, 1813, Orn. Dict. Suppl., not paged; text under Tern, roseate; pl. (Firth of Clyde,
Scotland).
Names: Synonyms of the specific name include bicwspis (described from Bahia, Brazil) and
gracilis, besides which the species has frequently been listed under the name paradisaea.
Characters: The pink suffusion on the under side of the body distinguishes adults of this species
ROSEATE TERN 1117
from other terns, besides which the outer (as well as the inner) web of the outermost rectrix is
white; the bill is mostly black during the northern-summer season and not more than basally red at
other times.
Adults in summer (sexes alike): Pileum, nape, and upper half of lores uniform deep black; rest
of upper parts plain pale gray (pallid neutral gray) passing into silvery white on upper tail coverts
and tail; secondaries tipped with white, and inner webs of primaries broadly edged with the same;
outermost primary with outer web dark gray or blackish slate, the inner webs of three outer
primaries white with a stripe of silvery gray next to shaft, the white extending to the extreme
tip; lateral and lower portions of head and neck, lower hind neck, and entire under parts, includ-
ing axillars and under wing coverts, immaculate white, usually more or less deeply tinted with
pink, especially on under parts of body; bill black, usually more or less reddish at extreme base
(mostly red in pre-nuptial season); iris dark brown; legs and feet pure vermilion-red or scarlet
Cin life).
Adults in northern-hemisphere winter: Similar to the summer plumage, but forehead and
anterior portion of crown white, the latter shaded with grayish and indistinctly streaked with
darker, only the orbital region, occiput, and nape uniform black (Ridgway, 1919, 505).
Measurements of adults of both sexes taken off Bahia, Brazil, in April substantially agree
with those of northern-hemisphere birds except for the lesser average length of the tail due, no
doubt, to a recent moult of these quills. They are as follows: wing, 220-231 (225.7); rail, 160-169
(164.1); exposed culmen, 32.2-38.3 (35.4); tarsus, 19.1-19.5 (19.3); middle toe and claw, 22-23.9
(23.1) mm.
Young: Pileum and nape pale buffy grayish, finely mottled or stippled with darker, and
streaked, especially on crown, with dusky; orbital region and upper portion of auricular region
dusky or blackish; remainder of head, lower hind neck, and entire under parts white, the hind neck,
and sometimes sides of breast, finely mottled with buffy grayish; back, scapulars, wing coverts,
rump, upper tail coverts, and tail pale gray, the back and scapulars overlaid or washed with pale
buff, irregularly mottled with dusky, each feather with a subterminal V-shaped mark of dusky;
primary coverts and primaries darker gray, edged with paler, the inner webs of the latter broadly
edged with white; rectrices each with a subterminal V-shaped mark of dusky and with outer web
rather darker grayish; bill brownish dusky; legs and feet dusky (in dried skins).
Downy young: Upper parts pale grayish buffy or buffy grayish, thickly flecked or irregularly
streaked with dusky; anterior portion of forehead uniform dusky; throat and lateral portions of
head and neck dull grayish; rest of under parts immaculate dull white; bill brownish, tipped with
blackish; legs and feet dusky (Ridgway, 1919, 505).
The eggs are described as follows by Bent (1921, 259): The eggs of the Roseate Tern are similar
to and often indistinguishable from, those of the other small terns; but when a large series is com-
pared with others the average difference is well marked. They will average a trifle longer and
the markings are smaller and more evenly distributed, with fewer of the large bold markings when
compared with a series of eggs of the Common Tern. There is less variation in the ground color,
which ranges from “‘cream-buff”’ to ‘‘cartridge-buff"’ or “‘pale olive-buff.’’ The darker and richer
colors of other terns’ eggs are seldom, if ever, seen in this species. A majority of the eggs are evenly
sprinkled with small spots or dots over the entire surface, either with or without an occasional
larger spot; these spots are seldom large enough to be called blotches and never as large and con-
spicuous as they are on the eggs of the Common Tern. These markings are in the darker shades
of brown from ‘‘warm sepia’’ to ‘‘dark clove-brown."’ There are often numerous spots of vari-
ous shades of violet, plumbeous or lavender-gray, underlying the darker markings. In shape
the eggs vary from ovate to elongate-ovate, usually quite pointed. The shell is smooth, thin,
and without lustre. The measurements of 87 eggs, in the United States National Museum, average
42 by 30 mm.; the eggs showing the four extremes measure 45.5 by 31, 43.5 by 32, 38 by 30, and
44 by 27.5 mm.
Distribution: Breeds on both coasts of the North Atlantic Ocean, from Sable Island to Long
Island, in Florida, Bermuda, the Bahamas, the Lesser Antilles, and Aruba Island in the Caribbean;
in Europe from the British Isles and Denmark, south to North Africa. Winters from the southern
United States to Brazil and South Africa.
1118 OCEANIC BIRDS OF SOUTH AMERICA
On April 28, 1916, Mr. Beck collected seven Roseate Terns off Bahia, Brazil.
His notes say that they were feeding among Common Terns (JS. hirundo) and
Wilson's Petrels, of each of which he obtained a series on the same date. Both
the terns and the petrels were resting on the ocean during dead calm periods of
the day, to rise into the air and feed again when light cat’s-paws rippled the
surface of the water. Other species collected on the same occasion include
Noddies and Brown Boobies..
The Bahia Roseate Terns are in winter plumage, with white foreheads, and
quills which have not attained full growth. Most of the specimens still retain
the pink bloom upon the breast to a far greater extent than those of a series
obtained by Beck at St. Thomas, West Indies, during August and September of
the next year.
Among the Lesser Antilles, the Roseate Tern breeds at many islands, and is
known among English-speaking natives as the ‘‘Carrect.’’ At Carriacou, of
the Grenadines, two eggs are laid in May, generally on the bare ground but
sometimes among tufts of grass. The birds fish in active, noisy flocks, making
perpendicular plunges into the sea, and during the middle of the day they usually
take a siesta on the rocks (Wells, 1902, 239). The only recorded breeding
colony actually within the South American region seems to be that on a coral
reef off the island of Aruba, in the Caribbean Sea. Here Hartert (1893, 310)
found the birds laying three eggs in June, either on the open sand or among the
green beach plants.
The Roseate Tern is single-brooded, and its period of incubation has been
established as 21 days. Its life history, including the courtship, nesting, plumage
sequences, behavior of young and adults, and food habits, has been learned in
considerable detail from studies of the North American and European repre-
sentatives, but little is yet known about its movements in South America.
BRIDLED TERN
Sterna anaethetus melanoptera
Sterna melanoptera Swainson, 1837, Birds W. Afr., 2, p. 249 (West Africa).
The following name, based upon New-World specimens, is believed to be 2 synonym:
Melanosterna anaethetus recognita Mathews, 1912, Birds Australia, 2, p. 403 (Bahama Islands).
Names: The Bridled Tern appears in the literature under the specific names pannaya, pannayensis,
discolor, and anaestheta. Furthermore, six or more subspecies have been described, the status of
several of which is uncertain.
Characters: The back scapulars, wings, rump, upper tail coverts, and six to ten middle rectrices
are deep brownish gray, paler and grayer toward the hind neck which is white or pale gray; inner
webs of primaries wholly dusky.
Adults (sexes alike): Forehead and superciliary region, lower portion of lores, suborbital
region, lower portion of auricular region and entire under parts, including axillars and under wing
coverts, immaculate pure white; lower hind neck grayish white or very pale gray; crown, occiput,
nape, upper hind neck, post-ocular region (including upper portion of auricular region) and broad
stripe across lores (from bill to eye) uniform black; back, scapulars, rump, upper tail coverts and
eight middle rectrices plain blackish fuscous, becoming more grayish (nearly Quaker drab) on
upper back, where fading anteriorly to grayish white on lower hind neck; wings deeper fuscous
BRIDLED TERN 1119
black, the primaries darker (more nearly black), the anterior margin of wing, abruptly, pure
white; outermost pair of rectrices' white, with terminal portion of inner web brownish gray, the
next pair similar but with much more gray, this on terminal portion of outer web also; the third
pair (from outside) with the dusky grayish general color passing into white basally, more exten-
sively on inner web; inner webs of primaries with an extensive, well-defined ‘‘wedge"’ of white;
bill, legs and feet black.
6 males: wing, 251-263 (257); tail, 147.5-164 (155.1); exposed culmen, 39-41 (39.9); tarsus,
19-21 (20.2); middle toe [without claw], 22-23.5 (23) mm.
5 females: wing, 255-263 (258.8); tail, 150.5-174 (162.9); exposed culmen, 38-40.5 (39.2);
tarsus, 19.5-20.5 (20); middle toe [without claw], 22-24 (22.9) mm. (Ridgway, 1919, 512).
The length of middle toe and claw in one male and one female is, respectively, 29.2 and 28.2 mm.
Young stages: The downy young Bridled Tern is gray, to match the rocks on which it is born.
The color varies from very light gray to dark gray or drab-gray, and it is usually tinged with buff;
the under parts are grayish white and the throat is dark gray; the upper parts are more or less
mottled with dark brown. The young bird, in the juvenal plumage, has the forehead and the entire
under parts pure white. The crown and hind neck are ‘‘light gull gray,’ lightly streaked on the
crown and heavily streaked on the cervix with black. The feathers of the back, lesser wing coverts,
or scapulars, are edged with pale buff, which fades or wears away during the fall and winter,
leaving the back ‘‘gull gray,’’ and somewhat mottled. The sequence of plumages to maturity, so
far as we can tell from the limited material available, is apparently similar to that of the other
small species of the genus Sterna. The same is probably true of the moults and plumages of the
adult. The adult in winter may be distinguished from the young of the year by having no buffy
edgings on the upper parts, but the fresh feathers of the back are broadly tipped with very “‘pale
gull gray,’ or whitish; and the head is more distinctly marked with black and white, though in
a similar pattern to that of the young bird (Bent, 1921, 289).
The eggs are somewhat similar to those of the Sooty Tern, and are nearly as handsome, but
they do not show such a wide range of variation and are usually much more finely and evenly
spotted, the bold, striking color patterns being seldom seen. The ground color is pinkish white,
creamy white, or pure white, which is generally well covered with rather small spots of a great
variety of shades of brown, from the darkest shades to bright reddish brown, also various shades
of drab, gray, violet, and lavender; occasionally an egg is boldly splashed or blotched with violet-
gray or lavender, overlaid with bold markings of brilliant shades of brown, and producing a very
pretty effect. The measurements of 20 eggs in the United States National Museum average 46 by
33.2 mm.; the eggs showing the four extremes measure 49.5 by 31.7, 47.5 by 35.5, 40.6 by 31.7 and
43.1 by 31.2 mm. (Bent, 1921, 288).
Distribution: Breeds in the Bahama Islands, and in the West Indies from the Lesser Antilles
westward and southward to the coast of British Honduras and to Aruba Island, off the coast of
Venezuela.
Tobago and Aruba seem to be the closest breeding stations of the Bridled
Tern to the continent of South America, and only the colonies at the latter island
bring the species within our region. At Aruba the Bridled Terns have been
found nesting in June (Cory, 1909, 195).
During the Brewster-Sanford Expedition this species was encountered only
at islets off St. Thomas in the West Indies, where Mr. Beck collected a series of
specimens during August, 1916. Here most of these terns had evidently passed
their breeding season, for a number of fledglings are included among the speci-
mens. However, Beck found that a few nests at Cockroach and Cricket Islets
still contained eggs as late as August 10. The flying young have broad buffy
edgings on the feathers of the dorsal surface, which appear to be lost rapidly
through wear. Their backs consequently become gradually darker, while their
heads tend to become lighter.
1120 OCEANIC BIRDS OF SOUTH AMERICA
At Aruba, Hartert (1893, 310) found the Bridled Terns breeding on a coral
reef in late June. The single egg was in every instance more or less hidden under
shrubbery or within the shadow of a stone or shell, instead of being laid in the
open as were the eggs of Roseate Terns in the neighborhood. This agrees with
the reputed régime of the species at Jamaica and the Bahamas, where eggs have
been found not only under overhanging ledges of rock but even inside the
entrances of abandoned Audubon’s Shearwater burrows (Bonhote, 1903, 314).
In still further confirmation of the trait, Bowdish (1902, 357) states that on
islets off Porto Rico, where the Bridled Terns were just beginning to breed on
June 24, the eggs were laid in more concealed spots than those of their neigh-
bor, the Brown Noddy. Wetmore (1918, 338) adds that at Desecheo Island,
Porto Rico, he found nest-platforms made of loose pebbles and chips of lime-
stone, with perhaps a feather or two, but always in situations well protected
from the rays of the sun.
The Bridled Tern is one of the “‘egg-birds’’ of the West Indies, sharing with
the Sooty Tern and the Noddy the privilege of having its colonies regularly
raided by hungry black men. It associates much with the two last-named terns,
although it appears to be a considerably shyer bird, except on thé nesting ground
where, on the contrary, it is highly pugnacious in attacking. Although credited
with being difficult to distinguish from the Sooty Tern, its grayish back, and,
even more, its evidently smaller size, makes discrimination in life rather simple,
especially if the two species are about together. On the wing, it is swifter and
more graceful than the Sooty. Furthermore, the voices of these two birds are
very different. In addition, the Bridled Tern frequently sits upon the water in
flocks, in this respect being very unlike the Sooty Tern, which goes to any
length to avoid swimming.
Its relationship with the Sooty Tern is evidently close, for these two species
have been by many authors placed in a distinct genus (Onychoprion). However,
the generic characters are based in large measure upon the anomalous and un-
tern-like coloration of the young of the Sooty Tern, and Ridgway (1919, 486)
has called attention to the fact that the young of Sterna anaethetus do not agree
with those of Sterna fuscata but are, on the contrary, typically tern-like.
A form of this tern, which has been named Sterna anaethetus nelsoni by Ridg-
way, is credited with a range along the west coast of Mexico and Central
America. Its breeding grounds are unknown, but Wetmore (1923, 171) has
recorded an immature female, taken in the Bay of Panama on September 24,
1922, which brings the supposed race within our region.
SOOTY TERN
Sterna fuscata, and its subspecies
Sterna fuscata Linnaeus, 1766, Syst. Nat., edit. 12, 1, p. 228 (Santo Domingo).
The latest list of forms of the Sooty Tern records six distinct subspecific names (Peters, 1934,
338), with the acknowledgment that the arrangement is purely tentative and that the species
fuscata is much in need of revision. In the list of Peters, moreover, no provision is made for the
form now known to occur in the eastern South Pacific, for this part of the ocean is not even included
SOOTY TERN 1121
within the numerous ranges which he gives. It will be well, therefore, to treat the Sooty Tern
mainly as a species, listing also additional names which may prove applicable to the Caribbean,
South Atlantic, and South Pacific birds discussed in the text.
Besides the typical or Atlantic subspecies, the following names have been proposed for forms
that enter the South American region:
Sterna fuscata crissalis:
Haliplana fuliginosa var. crissalis Lawrence, 1872, Proc. Boston Soc. Nat. Hist., 14, p. 285 (Socorro Island,
Revilla Gigedo Group, Mexico).
Under parts much less purely white than in S. f. fuscata, the gray tinge being stronger and ex-
tending forward to the chest. Inner webs of lateral rectrices terminally dusky.
Range: The eastern tropical North Pacific, breeding from the Tres Marias and Revilla Gigedo
Islands southward to Culpepper and Wenman Islands, at the northerly tip of the Galapagos
Archipelago.
Sterna fuscata luctuosa (?):
Sterna luctuosa Philippi and Landbeck, 1866, Arch. Naturg., 32, p. 126 (Rio Valdivia, Chile).
Not a properly defined race, because it has not yet been distinguished from the Sooty Terns of
southern Polynesia, for which another name may have priority. It is, however, larger than
S. f. crissalis, and perhaps even grayer ventrally and more dusky on the rectrices.
Range: Breeding at San Felix Island, Chile, close to the Sub-Tropical Convergence. Known
also from waters about the Juan Fernandez Islands, and from the coasts of Chile and Peru, which it
reaches perhaps only at times of exceptional meteorological or hydrographic conditions.
The following data refer principally to the Atlantic race (Sterna fuscata fuscata).
Names: Wideawake; Egg Bird at many islands of the West Indies and at St. Helena; Twa-oo
at Dominica and other islands of the Lesser Antilles. Synonyms of the specific name include
fuliginosa, spadicea, and I herminieri. Many subspecific names have been applied to birds inhabiting
various parts of the pan-tropical oceans.
Characters: The blackish dorsal surface and white breast serve to distinguish the species from
any other tern within the South American region.
Adults (sexes alike): Forehead (including latero-frontal antiae and a lateral extension on each
side of crown as far backward as middle of eye), suborbital region, lower half or more of auricular
region, and entire under parts, including axillars and under wing coverts, immaculate white, the
posterior under parts (especially under tail coverts) very faintly tinged with pale gray; crown,
occiput, nape, upper portion of auricular region, and broad stripe on lores (from lower portion of
lateral base of maxilla to anterior angle of eye) uniform deep black, this extending narrowly above
eye; rest of upper parts, including hind neck, rump, upper tail coverts, and tail plain fuscous black,
the remiges with a somewhat grayish cast, the feathers of hind neck white beneath surface; an-
terior margin of lesser wing covert area, abruptly, white; lateral pair of rectrices white, with distal
portion of inner web, more or less extensively, dusky; next pair of rectrices with inner web blackish
distally, passing into pale gray or grayish white basally; inner webs of primaries neutral gray with
a well-defined stripe of dusky next to shaft, the latter yellowish white; bill, black; iris, dark
brown; legs and feet, dusky or blackish (Ridgway, 1919, 513).
Adults in winter: Similar to summer adults but, according to Saunders, ‘‘with white flecks on
the lores and crown.”
For measurements of three subspecies entering the South American region, the table on p. 1123
should be consulted.
Young: Upper parts deep sooty brown (clove-brown to blackish brown or fuscous black), the
scapulars, interscapulars, tertials, smaller wing coverts, feathers of rump, and upper tail coverts
tipped with white or brownish white, the bars thus formed broadest on posterior scapulars, nar-
rowest on interscapulars, rump, and upper tail coverts; under parts lighter grayish brown (clove-
brown to dusky drab), passing into much lighter grayish brown or brownish gray on anal region
and under tail coverts, where the feathers are more or less distinctly tipped with a darker or more
brownish hue, the abdomen more or less intermixed with white; outermost (and other) rectrices
1122 OCEANIC BIRDS OF SOUTH AMERICA
wholly dusky; remiges as in adults, but darker stripe next to shaft on inner webs less distinct;
bill brownish black or dusky brown.
Downy young: Upper parts varying from dark sooty (fuscous black), narrowly streaked with
pale grayish buffy or dull buffy whitish, to pale buffy grayish narrowly and indistinctly, but
thickly, streaked with dusky; suborbital and malar regions and sides of neck and chest (usually
chin and throat also), light brownish gray minutely flecked with paler; rest of under parts immacu-
late dull white; bill brownish; legs and feet brownish dusky (Ridgway, 1919, 514).
Eggs: Bent (1921, 282) quotes Fisher regarding the highly variable eggs of the Sooty Tern.
The ground color is white or cream-buff. One type of marking consists of deep burnt sienna and
grayish vinaceous spots, with occasional nearly black scrawls scattered rather evenly over the
whole surface. The spots are 1, 2, and 3 mm. in diameter, with occasional larger and smaller ones.
Another less-prevalent variation consists of heavy, very deep burnt sienna blotches (5 to 15 mm. in
extent), congregated in a zone near the blunt end, and lesser pale grayish vinaceous and deep
burnt sienna spots sparsely scattered over the rest of the egg. A very handsome type has the brown
laid over the vinaceous, and occasionally the deep burnt sienna or chestnut shading off to one side
into light, caused by the spiral twisting of the egg in the oviduct. One specimen shows this to a
marked degree, having long chestnut daubs extending spirally from the big end. Still another type
has fine brown and grayish vinaceous maculations scattered all over the egg, but more numerous
at the blunt end. An abnormal specimen is entirely without markings, being pure white. The
shape is ovate, either elongate or thick. An average specimen measures 53 x 35 mm.
The measurements of 76 eggs, in the United States National Museum Collection, average
50 x 35 mm.; the eggs showing the four extremes measure 56 x 36, 54.5 x 37.5, 44.5 x 35, and
48.5 x 33 mm.
The above description may be based in large part upon Pacific specimens, but Witherby’s (1923,
718) notes and dimensions referring to eggs of the Atlantic subspecies very closely agree.
Distribution (of the Atlantic race): Breeds from the Bahamas, the Dry Tortugas, and other
islands through the West Indies to Caribbean islands off the coast of Venezuela; also at Fernando
Noronha, Rocas Reef, Ascension, South Trinidad, Martin Vas, and St. Helena. The subspecies
apparently ranges far during the period of its absence from nesting grounds, but of these migratory
movements practically nothing is known.
Distribution of the eastern Pacific races has been discussed above.
The Sooty Tern is one of the most abundant sea birds throughout the pan-
tropical oceans, nesting on the sands of countless islands in numbers that beg-
gar description. The manner in which birds of the species hang like canopies
of smoke above their breeding grounds—as seen from afar—the harsh clamor of
their screaming, snarling voices, their entertaining behavior during courtship,
the strange and skilful method by which they capture food, and their ability
to find their way unerringly across long stretches of open ocean, have been the
subject of many interesting accounts from the time of Audubon to the present.
An excellent summary, particularly as pertaining to northern-hemisphere colo-
nies of the Atlantic and Pacific, has been published by Bent (1921, 279). I shall
therefore confine what I have to say chiefly to southern-hemisphere represen-
tatives of the species, though it will, of course, not be permissible to omit the
essential data gathered by Watson during his studies at the Dry Tortugas, off
the southern tip of Florida.
Sooty Terns in the collection of the American Museum include many ex-
amples from various parts of the West Indian region, together with an excellent
series obtained at the South Atlantic islands of Fernando Noronha, Rocas Reef,
Ascension, South Trinidad, Martin Vas, and St. Helena by the ‘Blossom’ expedi-
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1124 OCEANIC BIRDS OF SOUTH AMERICA
tion of the Cleveland Museum of Natural History. Furthermore, we havea small
series from the eastern tropical Pacific (S. f. crissalis), received in exchange from
the California Academy of Sciences, as well as two males and two females shot
by Mr. Beck, during the Brewster-Sanford Expedition, in latitude 33° S., longi-
tude 74° W., on December 5, 1913. The last position is due west of Valparaiso,
Chile, about one-third of the distance between the continental coast and the Juan
Fernandez Islands. The gonads of these four eastern South Pacific specimens
indicated that the birds were at the height of their breeding season. Since their
measurements, particularly in length of wing, average considerably larger than
those of Sterna fuscata crissalis, as recorded by Snodgrass and Heller (1902, 505),
Gifford (1913, 19), Ridgway (1919, 519), McLellan (1926, 284), and other au-
thors, I am listing the Chilean specimens provisionally under the subspecific
name /uctuosa, of Philippi and Landbeck, at the same time admitting that this
is not yet a properly defined race.
The probable breeding source of Beck’s specimens became for the first time
revealed during the recent cruise of the yacht ‘Zaca,’ when three adult and three
fledgling Sooty Terns were collected by Mr. Templeton Crocker and Dr. Chapin
at San Felix Island, on February 18, 1935.
With seven adult specimens from the eastern South Pacific in our possession,
it might be supposed that their taxonomic status could be at once determined.
The matter is complicated, however, by the fact that these birds appear to re-
semble very closely Sooty Terns from the Tuamotu Archipelago, the Marquesas
Islands, and other parts of Polynesia, to which one or more subspecific names
older than /uctuosa may be applicable. They are of large size, very gray on belly
and crissum, with dusky inner webs on the long rectrices. For the present, I
merely wish to point out that they seem to be racially different from crissalis of
the equatorial and north tropical eastern Pacific, leaving final systematic treat-
ment until such time as the large series of Sooty Terns obtained by the Whitney
South Sea Expedition can be compared as a whole. All recent authorities, in-
cluding Witherby (1923, 718) and Peters (1934, 338), have emphasized that an
understanding of the subspecific relationships among Sooty Terns must await a
thorough revision.
Further reference to the accompanying table of measurements confirms the
deduction to be drawn from plumage comparisons that the Atlantic birds from
all breeding localities between the Bahamas and the island of St. Helena repre-
sent one race, and that the sexes do not differ appreciably in size except that
females have, on the average, slightly shorter bills than males. The total
length of specimens measured in the flesh proves highly various because of the
pronounced discrepancies in the length of the longest tail feathers, due to moult
and wear. However, this dimension in 14 males from Ascension averaged 429
millimeters. The average expanse of the tightly outstretched wings in 14 males
measured at Ascension by Mr. G. F. Simmons, leader of the Cleveland Museum
Expedition, amounted to 897 millimeters. These figures are not very different
from measurements of examples of the eastern tropical Pacific race, as taken by
Beck and recorded by Gifford (1913, 23).
SOOTY TERN 1125
Let us consider first the birds of the Atlantic and typical subspecies:
Although accidental records of the Sooty Terns have been made at many ex-
tralimital localities between Maine, Europe, and the Falkland Islands, there
are extraordinarily few published notes on birds seen in any abundance at a dis-
tance from their breeding grounds. This fact was long ago noted by Green (1887,
67) and it is all the more remarkable because the Sooty Terns at every great colony
are migratory, disappearing from their nesting territory as soon as the young
have been reared. Where they go remains one of the outstanding mysteries of
the sea. Unlike the noddies, they seem to have little use for solid supports,
flotsam, or the surface of the ocean itself as resting places. So far as yet known,
they are almost forever on the wing except for such time as they spend on terra
firma beside their nests. Burmeister long since pointed out their aversion to
swimming and their apparent inability to dive, while the experiments of Watson
(1910, 470) show that if they are confined to the surface of sea water for only a
few hours they become sadly bedraggled and soon perish by drowning. Brown
Noddies, after a whole night of similar treatment, come through dry and un-
harmed.
The breeding season of the Atlantic Sooty Terns as a whole seems to cover
the entire year, differing not only according to latitude, but, at some tropical
localities, varying from one year to another in a more or less regular succession.
The latter phenomenon has been observed particularly at Ascension. At the
Dry Tortugas Islets, off Florida, the Sooty Terns return annually about one week
after the noddy population. The early comers appear late in the first week of
May, and within four days practically all of the birds have reached their breed-
ing ground, after which eggs may be expected within a week (Thompson, 1903,
82). Farther southward, as on islets off Jamaica, eggs may be laid as early as
March. At Aruba and Los Hermanos Islands, off the coast of Venezuela, the
birds have been found breeding in large numbers during early February (Cory,
1909, 226). At South Atlantic islands they may appear either between early
August or December or at the same season as in the northern hemisphere. Thus
Simmons (1927, 71) found hundreds of thousands sitting on their eggs at Rocas
Reef, off the coast of Brazil, during April, and at South Trinidad and Martin
Vas during December and January. On the occasion of a visit to Fernando
Noronha in December, Nicoll (1904, 39) remarked that, although the Sooty
Terns were still breeding, he had come too late to find eggs. Meliss (1875, 98)
states that at George's and Speery Islets, off St. Helena, the terns normally ar-
rive each year toward the end of December and lay their eggs between January
and March, all the birds disappearing as soon as the breeding season has ended.
The data as regards scattered localities are, in short, rather confusing. Perhaps
each island colony is more or less a law unto itself, and it may be more profit-
able to consider the sequence at a single station which has been under obser-
vation for a long period, such as the famous ‘‘Wideawake Fair’’ at Ascension,
which lies close to the eighth parallel of south latitude in the very middle of
the Atlantic.
My notes on the Sooty Terns at Ascension are taken from the following
1126 OCEANIC BIRDS OF SOUTH AMERICA
sources: Collingwood (1867, 979), Sperling (1868, 286), Meliss (1875, 98), Gill
(1878, 145), Thomson (1878, 227), Moseley (1879, 563), Penrose (1879, 277),
Vanh6ffen (1905, 511), Brown, Mossmann, and Pirie (1906, 293), Wilkins
(1923, 510), and Simmons ( 1927, 74).
The Wideawake Fair is said to cover ‘‘ten or fifteen acres’’ (Sperling), or
“several square miles’ (Thomson), not far from the sea, in a valley toward
the southwestern part of the island (cf. Fig. 21, p. 152). The site is well shel-
tered from wind by the hills and is very oppressive under the full blaze of the
tropical sun, the more so because of an overpowering odor that arises from it
during the time that the birds are present. The stench comes not alone from
guano, but also from dead bodies of young and adults and innumerable cracked
or addled eggs, among which carrion beetles and their larvae swarm. From the
slopes of Green Mountain one can see the area as a greenish white patch, look-
ing as though the bed of cinders had been whitened by a light fall of snow,
while in the air above the wheeling and hovering terns appear like a pillar of
cloud that is never dissipated during the hours of daylight. The tremendous
noise, which is so discordant and ear-splitting at close range, blends in the dis-
tance to a sound like the murmuring of a vast crowd of human beings.
Besides the special aggregation at Wideawake Fair, there are or formerly
were several lesser colonies at Ascension, as well as one on the flat-topped ad-
jacent islet known as Boatswain-bird. The terns of these separate rookeries ar-
rive and depart with those of the Fair, and all observers agree that, on the aver-
age, the nesting season begins about three months earlier each successive year,
so that instead of nesting once a year the Sooty Terns breed about four times
in each three-year period. Wilkins puts the fact in other words when he states
that they return to nest about once every nine months. Thus the status of the
Ascension colonies at different periods of selected years is approximately as
follows:
The months regarded as the summer season run from October to January.
This is also the period during which the sea turtles come out of the ocean to
deposit their eggs upon the beaches. If we begin by dating the annual arrival
of the Sooty Terns from a period which might be regarded as early spring, we
can best trace the curious succession of the nesting seasons upon the basis of
scattered and incomplete data.
In early August, 1922, Wilkins found that most of the eggs had hatched.
Since the period of incubation lasts just under a month, the terns must have
arrived during this year some time in June.
Vanhoffen found, during the visit of the ‘Gauss,’ that the Sooty Terns were
breeding by hundreds of thousands on September 12.
Lady Gill, who spent several months in residence at Ascension, recorded
in her notes for September that great flights of small black-winged terns had
been observed for several days passing inland from the sea, and that at sunset
the sky was dark with them. The new outcry that their voices made in the
lonely island reminded her of the cawing of great flocks of rooks in England.
Every day they continued to pour in until October 5, or later.
Soot yy (TERN 1127
Penrose states that in 1877 the first returning Wideawake was observed dur-
ing the first week of October, and that the numbers continued to increase daily
thereafter for about two months, the height of the nesting season coming to-
ward the end of December.
Simmons, in 1925, also found egg-laying in full progress at Wideawake Fair
during December, 10,000 dozen eggs a week being collected for human food
during this period. Penrose, who refers to heavy egging during a certain Feb-
ruary, states that a good market-collector could gather 2000 dozen in a morn-
ing’s work. It is of incidental interest that this species is also the most im-
portant ‘‘egg-bird’’ in the Antilles. At islets off Jamaica the egging season
formerly extended from March to May (Gosse, 1847, 433), and large baskets
full of eggs from Tortola used to be a familiar sight in the public market of
St. Thomas (Taylor, 1864, 172).
Moseley, who visited Ascension in the ‘Challenger’ between March 27 and
April 3, 1876, found a single family of Sooty Terns breeding at this time on
Boatswain-bird Islet, and his notes seem to imply that others were to be found
at the Fair on the main island during the same period.
It would thus appear that the rhythm of reproduction at an island close to
the equator, such as Ascension, is correlated with some other external stimulus
than the succession of the seasons. At the Dry Tortugas, where there is a defi-
nite seasonal rhythm, the Sooty Terns come back for breeding each year on
practically the same date, while at Ascension the reproductive season evidently
varies from year to year in a manner highly deserving of further investigation.
Both Gill and Penrose write of minor irregularities, due to the collecting of the
eggs and the related disturbance of the birds. It is believed locally that a mated
pair of adults will persevere in laying again and again after their egg has been
taken. This, if it is a fact, might cause a marked and undue prolongation of
the breeding season, and tend to obscure the nine-month rhythm which seems
to be indicated. Furthermore, a great flood resulting from exceptional rainfall,
such as occurred at Ascension in 1876, may have the effect of destroying the
vast majority of eggs in the colony, causing the birds to renew courtship and
egg-laying, and delaying the whole routine up to the time that young and
adults leave the island together. Penrose states that, in the flood-year men-
tioned, the general exodus of birds was deferred until May, and that by August
of the same year the hosts were back again at Ascension for the beginning of
another breeding season.
As to their whereabouts during the pelagic interim, scarcely more is certain
than was known of bird migration in general throughout the not-distant dark
ages when the swallows of Europe were believed to winter in the mud beneath
ponds. However considered, it is almost incomprehensible that millions of con-
spicuous, black and white terns, which do not perch, which are incapable of
swimming without becoming sodden, which are unresting—flying perhaps for
days and days on end—should be almost unreported, swallowed up in the im-
mensity of the Atlantic.
The subsequent account of the habits of the Sooty Tern is abstracted in large
1128 OCEANIC BIRDS OF SOUTH AMERICA
part from Watson's (1908, 187) studies, made at Bird Key, of the Dry Tortugas.
Incessant fighting and screaming accompany the selection of nesting sites
by newly returned migrants. Thousands of birds are involved in such turmoil,
which represents the defense of family territories, of circular shape and from
30 to 75 centimeters in diameter, against late-comers. Concentration may fur-
ther reduce the area of the sites, and Dill has reported as many as nine nests
within one square meter at a Pacific ternery. Each mated pair assumes full
possession of the territory of its choice, and the noise and confusion of combat
continue both day and night. Usually a process of bluffing is sufficient to main-
tain the security of the nesting territory against trespassers. Birds in occupance
go through a “‘walkaround,”’ with heads cocked, wings closed, tail high, and
steps dainty, croaking at each other in a manner no doubt intended to be omi-
nous (Iredale, 1914, 436).
Mated birds are frequently lured outside their own charmed circle, however,
by the impulse to join in a struggle taking place a few paces away. When there
is a lull in the general disturbance, the mated pairs stand comparatively quietly
in their own respective territories. It is during such periods that copulation
takes place, and this is usually the time chosen for encroachment by neigh-
boring males.
As soon as a claim to a nesting area has been successfully established, the
mated terns proceed to form the nest depression by putting the breast to the
ground and scraping out the sand from beneath with their feet. The scratching
is continued during a complete rotation, birds of both sexes taking part, after
which leaves, shells, pebbles, or other decorative objects are sometimes picked
up and placed roundabout. On account of the crowding, and the quarrelsome
temperament of incubating birds, the exact localization of the nest, and the
ability to recognize both nest and mate, become the most important problem
in the life of the Sooty Terns.
During late afternoon in the Tortugas colony, Watson observed the female
Sooty Terns being fed by males, a process which usually attracted dozens of
other birds and precipitated a battle and a deafening outcry. During all this
courting season, before the eggs appear, the Sooties are shy and very restless
both by night and by day. Sleep is apparently not especially associated with
the hours of darkness, but is taken by very brief snatches of dozing at any time.
This is the peculiarity which has led to the popular nickname, Wideawake.
The Sooty Tern normally lays one egg. Watson noted 25 nests out of several
thousand that contained two, and the results of observers in colonies elsewhere
substantially agree (Dill, 1912, 14; Cassin, 1858, 386). In a single instance at
Dry Tortugas two chicks were actually hatched and reared within one nest.
The eggs are smooth and polished, unlike the dull-surfaced eggs of the noddy.
During the heat of the day the Wideawakes commonly stand astride the egg
instead of snuggling down upon it, a custom reminiscent of the incubating be-
havior of the Fairy Tern.
After the egg is laid, the mated Sooty Terns undergo a psychic change, and
become relatively bold in the presence of intruders. If driven from the egg, they
SOOT YTERN 1129
will at first flutter and drag their wings in a distracted manner. Their clamor
and gyrations make one giddy, and the continual proximity to one’s face of sharp
bills makes them seem dangerous, even though they may not be. Ordinarily
they remain much longer on the egg without relief than do their relatives, the
noddies. Watson once spent six hours in observation without seeing a single
tern leave its egg, except to make short excursions to drink from the surface
of the sea. During the laying and brooding season, the male of each pair com-
monly remains over the water all day, returning at nightfall to feed his mate
or to take a shift at incubation. The change normally takes place every twenty-
four hours, but Watson's table of observations shows that sometimes it may
not occur oftener than once in forty-eight hours. At the time of the transfer
the new arrival from sea pushes its mate off the egg, and the latter, after flit-
ting about for a few moments, is likely to come back and go through the same
act, temporarily regaining possession of the nest. This may be repeated several
times, and occasionally the previous sitter loses out, so that the wrong bird
ultimately joins the groups departing to feed. If the orientation of a returning
bird has not been exact, causing it to alight among terns which are not its
normal neighbors, it will surely have to run the gantlet of many sharp beaks
before finally reaching its own nest. When a returned male bird approaches
his mate, he arches the neck, droops the wings, lowers the head slightly, and
turns it to one side, and in this attitude struts round and round the female,
bowing repeatedly.
The period of incubation is 26 days, and the hatching of the egg produces a
further change in the instinctive reactions of the parents. Throughout the
first three days after the chick has appeared, the Sooty Tern is reluctant to
leave when disturbed, but after this length of time adults fly off at the slightest
stimulus, just as during the egg-laying season. Also, after the chick is about
three days old it is ready to leave the nest instantly at a note of alarm, and to
run to the nearest hiding place, where it remains motionless, thigmotactically
pressing its body against any conveniént solid object. At a subsequent clucking
call of the adult, the chick immediately responds. When the young birds first
hatch, the parents do not visually recognize their offspring, but react merely
by virtue of its presence in the nest. This Watson determined by exchanging
young birds. Within a few days after hatching, however, the chicks are identi-
fied with certainty by their respective parents, which strike forcibly at any
other young ones. There is, in fact, a mutual recognition between parents and
young through both sight and the sound of the voices.
During their first week of life, hundreds of chicks are killed by adults, es-
pecially by those which have no young of their own and are still engaged in
brooding an egg. When chicks start to crawl back from hiding places toward
their nests they are attacked, for example, by every sitting bird they pass. The
survivors soon gain agility and experience, however, learning to avoid dan-
gerous spots, and to dart quickly past threatening adults.
Parent Sooty Terns alternately feed the young at intervals varying from four
to seven hours. Feeding takes place at any time but is particularly in evidence
1130 OCEANIC BIRDS OF SOUTH AMERICA
at dusk, when the Sooties hurry homeward in great numbers. If a parent bird
disgorges more than the nestling can take in, and food accidentally falls to the
ground, the parent picks it up and reswallows it. Sometimes the adults appear
to tantalize the chick by repeatedly bringing up a piece of fish to the end of
the beak and then engulfing it again, while the chirping youngster vainly strug-
gles to obtain the morsel. The mate of a feeding parent has only the réle of a
spectator, except when other terns attempt to approach. Under such circum-
stances it assumes that aggression is the best defense.
After an age of 20 days or thereabouts, the young terns often wander from
the nest which still serves, however, as a localizing influence because the
parents continue to alight beside or near it when returning from their fishing.
When the chick has reached this age, the process of supplying sufficient food
is evidently exhausting to the parents, for they usually become somewhat ema-
ciated and dishevelled.
Watson's experiments in coloring eggs of the Sooty Tern, and in daubing
certain feathers of mated birds with unfamiliar pigments, showed that visible
changes of this kind are immediately noticed. The painted birds created great
disturbances, both as regards their mates and the colony as a whole, although
within a few hours the harmony of families, at least, became reéstablished. As
concerns eggs, it was revealed that the Sooty Tern is not capable of distinguish-
ing between its own and another, but that it is much puzzled and perturbed by
unusual egg coloration.
Tests involving removal of nest and egg showed that locality is the important
element in recognition, the nest being reacted to by virtue of its position alone.
Even when an entire small unit of the landscape, including a tussock of grass,
was moved a meter away, the returning Sooties would first alight at the origi-
nal site of their nest, and would become adjusted to the new position only
after periods of half an hour or more. The evidence was not conclusive as to
whether conditioning takes place only in terms of vision.
At sunrise the Sooty Terns are spontaneously most noisy. The individual
notes have been likened to a sharp staccato laugh, with which longer, more
musical tones are occasionally mingled. Soon after the break of day, the free
birds leave their island in search of breakfast, often mingling, purely from a
community of interest, with noddies, boobies, and other sea fowl over the
ocean. They feed without plunging or in any other way touching the water.
They capture their food rather by pursuing shoals of small fish, such as herrings
and carangids, and doubtless larval flying fish, and deftly picking these out of
the air as they leap above the surface. After sufficiently gorging themselves,
the Sooties spend much time in sheer aérial maneuvers, and sometimes join the
frigate-birds in soaring higher and higher until they are lost to sight.
Watson concluded that the Sooty Terns, like the noddies, do most of their
feeding within a short distance of the nesting ground, rarely foraging at points
as distant as 25 to 30 kilometers. In other parts of the world, however, they
have been observed in large numbers considerably farther from islands at which
they were nesting. Wilkins (1923, 510), for example, during the cruise of the
SOOT ¥ (TERN 1131
‘Quest,’ saw many over the sea up to distances of 320 kilometers on either side
of Ascension. Beck, too, observed that their daily range may take them away
as far as ‘‘200 miles.’’ Strictly pelagic records are, as noted above, exceedingly
rare, but Green (1887, 67) quotes the great Captain Cook's observations on
examples sighted ‘‘a hundred leagues’’ from the nearest land, and in the
British Museum, there are specimens collected at the mouth of the Amazon,
which is a long way from any nesting station.
In Watson's (1910, 470) homing experiments, four Sooty Terns which had
been confined below deck were released at night along the steamship course
toward New York, at a distance of 587 kilometers from Bird Key. One returned
to its mest at the expiration of four days, and a second after five weeks. The
route was certainly unfamiliar to the birds, and the means of orientation is un-
known. Brooks (1934, 190) raises the question as to whether the rich feeding
grounds along the margin of the Gulf Stream may not have played a part in
guiding the terns homeward, though the suggestion hardly offers a satisfying
explanation.
At Dominica and other islands of the West Indies, the Sooty Terns or ‘“Twa-
oos’’ have the reputation of appearing vagrantly along with squally weather
(Lawrence, 1878, 68), or still more during the calms that often precede disastrous
cyclonic storms (Ober, 1880, 179). The observation has been made or fancied
often enough so that they are sometimes called “‘hurricane birds."
Turning now to the Pacific, we are concerned with two forms of this species,
of which the Socorro Sooty Tern (crissalis) nests at certain islands from the
Revilla Gigedos southward only to the isolated, northernmost members of the
Galapagos Archipelago. It avoids, however, such humid stations as Cocos, as
well as all islands close to the South American continental shore. The presence
of a colony at Culpepper Island, Galapagos, affords an instructive commentary,
in the opinion of Swarth (1934, 221), upon the obscurity of factors governing
the distribution of species. Although this tern has bridged the wide gap be-
tween the metropolis of its kind, off the coast of Mexico, and the northern tip
of the Galapagos group, it has not taken the additional short step toward un-
limited nesting space afforded by other islands of the same cluster. At Wenman
and Culpepper Islands, just to northward of latitude 1° N., the Socorro Sooty
Terns are abundantly established. Doubtless it is the effect of cool Humboldt
Current water, of the negative departure between atmospheric and oceanic tem-
peratures (cf. p. 297), and a resulting influence upon surface food resources, that
bar the birds from the members of the Galapagos group which lie nearer the
equator or south of it.
The greater part of the range of the Socorro Sooty Tern is outside the field
of this book. Furthermore, its habits seem to agree substantially with those
of the Atlantic race, and they have been well described by authors cited at the
beginning of this biography.
We may therefore turn our attention to the subspecies of more southerly
parts of the eastern South Pacific, which I have provisionally listed under the
name /uctuosa. The region is one from which, until recently, Sooty Terns were
1132 OCEANIC BIRDS OF SOUTH AMERICA
supposed to be absent. Thus Saunders (1896, 110) wrote that the species is
“almost unknown on the South American side of the Pacific,’’ a belief further
emphasized by Gifford (1913, 19) when he called attention to lack of records
off the coasts of Colombia and Ecuador, and in the area extending between the
northernmost Galapagos and the well-known breeding grounds of Easter Is-
land, in the heart of the South Pacific. The records which have now changed
the accepted status of the bird are as follows:
An adult female, which was emaciated and had probably been transported
by storms, was shot in the Rio Valdivia, Chile, on August 2, 1855, and was
subsequently made the type of ‘Sterna luctuosa’’ (Philippi, 1902, 101). The cap-
ture of four specimens by Beck, west of Valparaiso, on December 5, 1913, has
been noted above. On December 7, somewhat nearer the Juan Fernandez group,
he saw more of these terns fishing with flocks of shearwaters, and not far from
Mas Atierra Island, on December 19, his notes refer to others which flew past
his sloop from the direction of the island.
At San Felix, on February 18, 1935, Chapin encountered moderate-sized
flocks of Sooty Terns at the latter end of their breeding season. Among them
were fledglings which had not quite reached the flying stage. The stomachs
of adults were empty at ten o'clock in the morning, while those of young con-
tained remains of both small fish and small squids. Lest a reader presume that
the cephalopods could have been captured only by diving—behavior to which
Sooty Terns are not given—attention should be called to the fact that certain
kinds of squids leap into the air, and are capable even of shooting clear across
the deck of a ship.
My own notebook contains an observation regarding many Sooty Terns off
Independencia Bay, Peru, on January 13, 1925. One or more of them flew close
to my vessel, so that I could examine them intimately through binoculars. It
should be especially noted that at this particular date the surface waters along
the greater part of the Peruvian coast had begun to be warmed through a cessa-
tion of upwelling in the Humboldt Current. Within a few days after the sight
record, indeed, temperatures of unparalleled warmth characterized this littoral.
It is exceedingly interesting and suggestive that Sooty Terns should be among
the organisms which serve as accompaniments, or even precursors, of such pro-
found, cyclic oceanographic phenomena as I have attempted to describe in
Part I of this book. Under the circumstances, it is hardly possible to guess
whether the Sooty Terns which ‘‘abnormally’’ appear along the coast of Peru
are immigrants from the equatorial Pacific to northward, or whether they wan-
der toward the continent from San Felix or from central tropical areas of the
South Pacific.
YELLOW-BILLED TERN
Sterna superciliaris
Sterna superciliaris Vieillot, 1819, Nouv. Dict. Hist. Nat., 32, p. 176 (Paraguay).
Names: River Tern; ‘‘Gaviotin Pequefio’’ or ‘‘Hati de Ceja Blanca’’ in Argentina. Synonyms
of the specific name include maculata and argentea.
Characters: The longer wing (exceeding 180 mm.) and the yellow bill without dark tip dis-
YELLOW-BILLED TERN 1133
tinguish this species from the white-breasted Least Tern of northern South America. The only
other very small species, namely Sterna lorata of the west coast, has the lower parts gray.
Adults in breeding plumage (sexes alike): Similar to the Least Tern (Sterna albifrons antillarum),
but larger and stouter, with a shorter tail; black loral streak very narrow; mantle and tail darker
gray, with a slightly brown tinge on the inner secondaries; four outer primaries chiefly dusky
black, with comparatively narrow white margins to the inner webs of the first two, and very
little white on the next two; iris Rood’s brown; bill entirely waxen yellow; tarsus and toes olive-
ochre; crus yellowish olive.
Adults after the autumn moult differ only in that the crown is flecked with white and the
lores are speckled with black.
Measurements of 2 males and a female in the American Museum from Brazil and Bolivia:
wing, 185-190; tail, 72.3-82; exposed culmen, 30.2-34.1; tarsus, 15.8-16; middle toe and claw,
18.7-19.4 mm. Wetmore (1926, 139) states that birds from southern South America appear to be
slightly larger than those from Colombia and British Guiana.
Immature: Lores and forehead white; crown gray, with blackish streaks which become con-
fluent round the eye and on the nape; primaries with a brownish tinge; bill yellow, with horn-
colored tip. Otherwise like the adult.
Young: Lores drab, a very marked whitish superciliary streak, forehead drab; crown darker,
flecked with umber; a black patch from behind the eye to the nape; mantle gray, tinged with buff
and barred with ash; tail mottled with ash, the ground color grayer than in any of the allied
species: bill dull yellow, the maxilla nearly horn-color; tarsi and toes dull yellow. Conspicuously
darker than the young of S. albifrons antillarum (Saunders, 1896, 125).
According to Oates (1901, 195), the eggs of this tern are similar to many of those of Sterna
albifrons, the ground color being of a warm buff and the marking rather small and delicate. Eight
specimens from branches of the Amazonian river system vary in length from 29.7-31.2 mm., and
in breadth from 23.1-24.1 mm.
Distribution: Rivers and coasts of South America, east of the Andes, from Colombia, Vene-
zuela, and the Guianas to Uruguay and eastern Argentina.
This little tern is very similar to the Least Tern except that its much larger
bill makes it look almost like a diminutive edition of the other common species
of South American rivers, the Great-billed Tern (Phaetusa). Young (1928, 766)
states, indeed, that these two are frequently seen in company, like big and
little brothers, along the coast of British Guiana. Hellmayr (1929, 497) appears
to regard superciliaris as an exceedingly close relative of the Least Tern, implying
that both of them are no more than races of one mainly holarctic species,
namely, Sterna albifrons. If this be correct, the division of habitat between
Least Tern and Yellow-billed Tern is, respectively, that of salt and fresh water,
at any rate in South America. Sterna superciliaris follows the larger rivers of the
continent to points thousands of kilometers from their mouths. In this respect,
as well as in appearance, it has become a sort of tiny counterpart of Phaetusa
simplex.
The Yellow-billed Tern was not taken during the Brewster-Sanford Expedi-
tion, nor in the course of any other coastal field work of the American Museum
in South America. Wetmore (1916, 139) encountered it in the country around
the estuary of the Rio de la Plata, and on January 9, 1921, saw two on the sea
beach near Carrasco, Uruguay, which behaved as though they were near their
nesting grounds. They darted constantly at the intruder’s head, with complain-
ing cries, until he had passed beyond their bounds. In the department of Rocha,
Uruguay, he saw a number of immature examples beating back and forth over
1134 OCEANIC BIRDS OF SOUTH AMERICA
a lagoon, in company with Trudeau's Terns. The young birds were expert
fishermen and were also exceedingly wary. Wetmore noted that in habits and
form this species is thoroughly suggestive of the Least Tern in North America,
and that it frequents similar localities along large fresh-water streams and
sea beaches.
PERUVIAN TERN
Sterna lorata
Sterna lorata Philippi and Landbeck, 1861, Anal. Univ. Chile, 19, p. 612 (Arica, Chile).
Names: In Peru this tern is called the ‘‘Churi-churi’’ from its singing call, and also ‘‘Cor-
binero’’ because it is said to follow the schools of corvinas and similar fishes. Fishermen also use
the term ‘‘Pardelito,”’ perhaps failing to distinguish between terns and petrels. In the scientific
literature the species has been listed under the names exilzs and Joricata.
Characters: From all of the other terns of least size that occur in the South American region
this species differs in having the dorsal surface, including the quills of wing and tail, largely gray
instead of white or whitish. The ventral surface of the body, likewise, is not white, but is of a
gray tinge, although somewhat lighter than the back.
Adults in breeding plumage (sexes alike): Forehead, as far as the middle of the superciliary
region, white; upper loral streak black, rather narrow, beneath which is a parallel whitish streak
along the cheeks; crown and nape black; mantle slaty gray; primaries white-shafted, the outer
web of the outermost black, a smoke-gray line on the inner web, next the shaft, with similar
lines of a lighter gray hue on succeeding primaries, the inner portions of the inner webs being
white; rump and tail quills slaty gray, the streamers of the lateral rectrices paler; breast, flanks,
and abdomen pale gray, passing into white on throat and chin; under wing coverts white. Iris
brown; bill yellow, with the culmen and tip blackish, very straight, slender, and prolonged in
front of the gonydeal angle; legs and feet yellowish.
Adults in winter: Similar, but with a streaky admixture of white in the crown.
Specimens taken between October and April are in breeding plumage; June birds in full winter
plumage.
11 males: wing, 166.7-187 (180.4); tail, 76.3-86.5 (80.7); exposed culmen, 30-34.1 (2.3);
tarsus, 13.8-15.4 (14.5); middle toe and claw, 16.6-17.6 (17.2) mm.
3 females: wing, 178-185 (181.7); tail, 77.6-87.4 (83.3); exposed culmen, 29.2-30.5 (29.9);
tarsus, 13.3-13.5 (13.4); middle toe and claw, 15.6-16.6 (16) mm.
A chick just emerging from the down, taken at Pacasmayo, Peru, January 2, 1920, is pale
buffy above and whitish on the belly, with blackish bars on the feathers of the dorsal surface.
The tips of the young primary quills projecting from the sheaths are practically black.
Two sets of two eggs, taken at Pacasmayo on the same date, are of short-ovate form, one in
each set being distinctly more pointed than the other. One set was fresh, the second heavily
incubated. The ground color is close to deep olive-buff, the outer pigmentation being in the form
of rather evenly distributed small spots and blotches of bister, which has a purplish cast wherever
it underlies the surface of the shell. Dimensions of the sets are, 30.1 x 22.8 and 29.9 x 23.7; 30.1 x
24.6 and 30.2 x 23.9 mm.
Distribution: Breeds on mainland and islands along the coast of Peru; recorded northward to
El Muerto Island in the Gulf of Guayaquil, Ecuador, and southward to the Bay of Arica, Chile.
The little Peruvian Tern is a thoroughgoing member of the Humboldt
Current avifauna, confined to the desert section of the west coast of South
America. The type specimen, an adult female obtained in the Bay of Arica
during September, 1851, appears to constitute the only Chilean record (Hell-
mayr, 1932, 407). However, the species undoubtedly ranges regularly south-
ward along the desert coast of Chile, because Beck notes the presence of a flock
PERUVIAN TERN 1135
at Arica on August 25, 1913. During practically the same season of the year,
namely in July of 1922, these terns were abundant at the mouth of Jambeli
Channel in the Gulf of Guayaquil, Ecuador (Chapman, 1926, 187).
Along the Peruvian coast the ‘‘Churi-churi’’ has been observed at many
localities by Mr. Beck and myself during our respective South American work.
The following records are from our notebooks:
Paracas Bay, October and November, 1919. Adults in breeding condition
collected. During the winter season, June and July, 1913, Beck observed num-
bers at the same locality, fishing well out from shore and then flying inland
with their catches. Coker (1919, 460) also found this tern abundant at Paracas
Bay at various seasons of the year.
Chorrillos, February 17, 1913. One collected.
San Lorenzo Island, off Callao, June 3, 1913. Beck found a dozen or more in
a valley near the highest summit of the island, the birds behaving as though
they were nesting, despite the fact that the season was midwinter. In this same
locality, MacFarlane (1887, 204) long ago‘observed these terns reacting similarly.
At Ancon, a short distance north of Callao, and at the outlying Pescadores
Island, both Beck and I found the terns common during April and December,
respectively, and I was told that they bred on the sandy plains behind the town.
At Pacasmayo I found them nesting in early January, 1920, as recorded below,
and on January 15 I observed numbers fishing off the south point of Lobos de
Tierra Island.
Finally on March 6, 1925, during an extraordinary period of strong counter-
current and heavy rains in northern Peru, I saw tens of thousands of the Churi-
churis in the harbor of Paita. It was a morning of downpour, and the terns
were the only active birds in the port, the pelicans, gulls, and cormorants being
mostly perched along the gunwales of lighters, many of them with their bills
tucked under the wing coverts. Presently, after the terns had apparently grown
tired of fighting the strong north wind, they alighted in little groups on floating
branches and other flotsam, of which a great quantity had come down from the
northward with the warm current known as El Nifio.
Previous to my first visit to Peru, the breeding habits of the Churi-churi
were still unknown. I learned that they nest not on the beetling cliffs as had
been suspected, but rather on the coastal plain or tablazo, well back from the
sea. In November, 1919, at Paracas Bay, I flushed many while crossing the
stony desert. They appeared to be nesting, although I found no egg. Early in
the morning they would begin to fly inland with food in their bills. On Novem-
ber 13, I followed them back from the bay over the sandy and pebbly wastes
behind, and the actions of the terns here left little doubt that this was their
nesting ground. Couples were flying roundabout above the pampa, calling
loudly to each other. Frequently birds from the bay passed over with small
fish carried crosswise in their bills. Two or three times, pairs became much
excited because of my presence, and would dash toward me in a characteristic
way, attracting other birds, until quite a throng was hovering about me. I
hunted a long time for young or eggs, but was unsuccessful. Yet I am sure that
1136 OCEANIC BIRDS OF SOUTH AMERICA
they must have been there, for when I had gone inland somewhat farther I left
all the terns behind and, although I occasionally heard their distant calls, I
did not come among them again until I passed through the same belt on my
return toward the shore. The voice of the Churi-churi, which gives it its com-
mon Peruvian name, is very entertaining. The single notes are sweet and mellow,
more like those of a sandpiper than of most terns. Occasionally the birds burst
into a cadence of cries that continues for perhaps five seconds, so that it con-
stitutes a veritable ‘‘song.”’
At Pacasmayo in northern Peru, on January 2, 1920, I again saw the Churi-
churis flying inland over the stony desert, and heard them in lively song, not-
withstanding the fact that they were all carrying minnows. Here it was easy
to discover their secrets, for, when I had followed the line of flight 2 kilometers
back from the beach, small groups of the terns dashed significantly toward my
head, chattering in protest. Ignoring these birds, I sat down and quietly scanned
the more distant parts of the plain through glasses. Presently I saw a Churi-
churi alight about 300 meters away. It stood still and seemed to look all
around. Next it preened its feathers in an abstracted manner, and pirouetted
several times. After that it trotted straight to a spot ten to twelve paces off
and settled down. I glued my eyes upon the bird and started toward it. It soon
flew but, without changing my glance, I walked ahead and found its two eggs,
which looked like harmonious pebbles on the sunburnt tablazo. By following
the same tactics I soon discovered two more eggs, and an equally well-camou-
flaged chick. In each instance the parent had descended at some distance, and
had completed its cautious scouting before approaching the bare site which
took the place of a nest.
The food of this little tern includes both fish and crustaceans, as has been
learned through examinations of the stomachs of specimens I collected in Peru.
Several taken at Paracas Bay during October and November contained anchovies
(Engraulis ringens and Stolephorus), as well as opossum-shrimps (Euphausia), the
small fishes usually making up between 90 and 100 per cent of the stomach
contents. It seems probable that when these terns follow the schools of the
‘‘anchobeta’’ (Engraulis), they pick out the tiniest examples, leaving the full-
grown fishes to boobies, cormorants, and gulls. Three specimens of the fishes,
about 5 centimeters in length or somewhat less than half grown, were found in
a single tern’s stomach. Incidentally, all but two stomachs among nine ex-
amples were crammed with food, and in most instances the entire gullet was
filled with the overflow.
LEAST TERN
Sterna albifrons antillarum
Sternula antillarum Lesson, 1847, Compl. Oeuvres Buffon, 20, p. 256 (Guadeloupe, West Indies).
Another subspecies, described from the Pacific coast of North America, is said to migrate south-
ward in winter to Peru, but little or nothing seems to be actually known of its South American
status. It was described as:
Sterna antillarum browni Mearns, 1916, Proc. Biol. Soc. Wash., 19, p. 71 (United States-Mexico boundary,
south of San Diego, California).
LEAST- TERN 1137
Names: Kill 'em Polly in the English-speaking Antilles. Synonyms of the specific name include
minuta, melanorhyncha, and frenata.
Characters: Under parts white or at most, very faintly tinged with gray; tail pale gray; wing
less than 180 mm.; bill usually tipped with blackish.
Adults in summer (sexes alike): Forehead and sides of crown white; a narrow stripe on lores
from bill to eye); crown, occiput, and upper portion of nape uniform deep black; rest of head and
entire under parts, including axillars and under wing coverts, immaculate pure white; upper parts,
including hind neck, rump, upper tail coverts, and tail plain pallid neutral gray, slightly deeper
gray on back, scapulars, and wings; two outer primaries dusky gray or blackish slate color, their
inner webs broadly edged with white, the remaining primaries pallid neutral gray (like coverts,
etc.), their inner webs edged with white; bill bright yellow, usually tipped with black; iris dark
brown; legs and feet orange-yellow Cin life).
Adults in winter: Similar to summer adults but lores, forehead, and crown grayish white
(purer white anteriorly), an occipital crescent and a stripe extending from this to and surrounding
eye, blackish; bill blackish or dusky; legs and feet dull yellow.
14 males: wing, 163-178 (168.1); tail, 70-93 (81.2); exposed culmen, 26-31 (28. 8); tarsus,
14-15.5 (14.5); middle toe [without claw], 11.5-13.5 (2.8) mm.
13 females: wing, -160-467 (162.9); tail, 61-85.5 (72.9); exposed culmen, 25.5-30 (27.5);
tarsus, 14-16 (14.7); middle toe [without claw], 11-13 (12.2) mm.
Young: Somewhat like winter adults, but humeral region with a broad space of dusky grayish,
scapulars and interscapulars with V- or U-shaped submarginal marking of dusky, crown streaked
and occiput mottled with dusky, and primaries darker gray; bill dusky, more brownish basally;
legs and feet brownish (in dried skins).
Downy young: Upper parts buffy white to deep pinkish buff, nearly immaculate, but with
one or more small irregular black spots on occiput, or on occiput and crown, and a few small and
indistinct irregular spots or streaks of dusky on rump; under parts immaculate white or buffy
white, the throat usually more buffy; bill pale yellowish brown, tipped with dusky; legs and
feet pale yellowish (Ridgway, 1919, 521).
The eggs of the Least Tern are good examples of protective coloration, for they match their
surroundings remarkably well and can hardly be distinguished from mottled pebbles. The usual
ground color varies from deep rich ‘‘cartridge-buff”’ to very ‘'pale olive-buff,”’ or toa color between
“pale olive-buff’’ and white. This is more or less unevenly sprinkled with small spots, and some-
times with a few large spots or blotches of dark shades of brown, such as ‘‘Mars brown," “‘sepia,"’
or ‘‘mummy brown."’ Most eggs show some spots and many, particularly of the lighter types,
show large underlying blotches of *‘Rood’s lavender’’ or other shades of ‘‘lavender gray.'’ Some
eggs show very handsome patterns of bold dark markings over lighter shades. The shape varies
from ovate to short-ovate and the shell is thin and lustreless. The measurements of 63 eggs, in
the United States National Museum, average 31 x 23.5 mm.; the eggs showing the four extremes
measure 37 x 24, 28.5 x 23, and 29.5 x 22 mm. (Bent, 1921, 275).
Distribution: Breeds on the Atlantic and Gulf coasts of North America from Massachusetts
to Florida and Texas and also on islands in the Mississippi River system; the Bahama Islands,
many islands of the West Indies, islands of the Caribbean coast of Central America and northern
South America. Winters southward from the Gulf coast of the United States to northeastern Brazil.
The South American status of the Least Tern, along either Pacific, Caribbean,
or Atlantic shores of the continent, seems to be highly uncertain. Doubtless
its identity has been confused in the ornithological literature with that of
Sterna superciliaris and other forms. According to the distributional data quoted
above from Peters (1934, 341), this bird reaches the coast of Brazil during its
winter migration, while the western subspecies is said, on doubtful grounds,
to be known from Peru.
At Margarita Island, off the coast of Venezuela, the Least Tern has been
1138 OCEANIC BIRDS OF SOUTH AMERICA
found abundantly in July, and young birds have been taken during the same
month at Aruba Island.
Neither the typical West Indian form of the Least Tern, nor the Pacific form
(brownt), appears to be known from western Colombia or Ecuador. Chapman
(1926, 187) has identified as Sterna lorata the small terns he observed in the Gulf
of Guayaquil in the southern-hemisphere winter period.
ROYAL TERN
Thalasseus maximus maximus
Sterna maxima Boddaert, 1783, Table Planches Enlum., p. 58 (Cayenne).
Names: Crickum at Corn Island in the Caribbean; ‘‘Gaviotin Real’’ or ‘‘Gaviotin Mayor’’ in
Argentina; ‘‘Tijereta’’ in northern Peru; ‘‘Gaivota’’ in Brazil, the name for all the larger terns.
Synonyms of the specific name include cayanus, cayennensis, galericulata, erythrorhynchos, regia, and
cristatus.
Characters: The largest American representative of the crested terns, with a wing exceeding
350 mm. in length; bill red.
Adults in breeding plumage (sexes alike): Entire pileum, including occipital crest, nape, and
upper half of lores, uniform deep black; rest of head and neck, under parts, rump, upper tail coverts,
and edge of wing immaculate pure white; back, scapulars and wings pale gray (pallid neutral gray,
sometimes approaching pale neutral gray), the outer web of outermost primary darker gray; inner
webs of primaries with a deep or dark gray broad stripe next to shaft, this dark gray continued
across tips and for some distance along inner edge, the remainder white; tail grayish white, more
or less tinged with pale gray; bill orange or reddish orange; iris dark brown; legs and feet black.
Adults in northern-hemisphere winter: Similar to the post-nuptial (?) plumage, but black of
occiput and nape also intermixed, more or less, with white, and bill paler orange (Ridgway,
1919, 467).
Measurements of specimens from Santo Domingo, Panama, Ecuador, and northern Peru agree
well with those recorded for North American birds, the relatively shorter wings and tails being
doubtless due to the state of the winter plumage.
4 males: wing, 360-376 (367); tail, 153-168 (162.6); exposed culmen, 63-68.1 (65.2); tarsus,
32-35 (33.3); middle toe and claw, 32-34 G3.7) mm.
3 females: wing, 333-345 (339); tail, 132-153 (144.3); exposed culmen, 58.3-62 (59.9); tarsus,
30.8-35.5 (32.4); middle toe and claw, 31.1-36.4 (34.6) mm.
Young: Somewhat like winter adults, but upper parts sparsely spotted with dusky grayish
brown, these spots largest on tertials; rectrices deep grayish brown or dusky subterminally; pileum
speckled or flecked with white or dusky, the occipital crest but slightly developed (Ridgway,
1919, 468).
Distribution: Breeds in North America on the Pacific coast of Mexico, and on the south Atlantic
and Gulf coasts from Virginia to Texas; also in the Bahamas and West Indies. Winters from Cali-
fornia to Peru, and from the Gulf coast of the United States southward to Argentina.
Southward bound at the beginning of the Brewster-Sanford Expedition, Mr.
Beck saw many Royal Terns in the Pacific off Panama, on December 27, 1912.
Records of the species along the northern coasts of South America are so numer-
ous that I shall confine my notes chiefly to observations made close to the south-
ern limits of the range, on both Atlantic and Pacific coasts.
During my own work in Ecuador and northern Peru, I found the Royal Tern
to be a common species between Cape San Lorenzo and Paita. In this region the
native name by which the bird is known to all the coastal Indians is the diminu-
tive term ‘‘Tijereta,’’ which distinguishes it from the larger ‘‘scissor-tail,"’
ROYAL TERN 1139
namely, the ‘‘Tijera’’ or man-o’-war bird. Of great interest is the fact that
the Royal Tern is one of the species associated with tropical waters which ap-
pears to be most sensitive to temperature changes. Consequently, as I have
mentioned in Part I of this book, the extension of its distribution along the
littoral near Point Parifias, the westernmost projection of the South American
continent, depends upon prevailing current conditions. So long as a northward
movement of waters, accompanied by upwelling, is in progress, the wintering
Royal Terns remain mostly to northward of Point Parifias. As soon, however,
as a barometric high near the equator causes a southward flow of the counter-
current called El Nifio, the Royal Terns and other warm-water species of birds,
together with giant rays, flying fishes, etc., tend to move southward along the
Peruvian coast into what is normally the Humboldt Current zone.
Between November, 1924, and March, 1925, I saw many examples of this
species between Talara, Peru, and the outer coast of Ecuador, where on February
14 I collected two males in Santa Elena Bay. During the same season it was
common not only in all parts of the Gulf of Guayaquil, but even well up the
River Guayas, beyond the reach of salt water. At the end of February, after
the notable southward advance of the warm countercurrent of that year, the
Royal Terns were also abundant in the Bay of Paita, Peru.
Subsequently, Chapman (1926, 186) recorded the species as not uncommon
near Jambeli Island, Ecuador, during the middle of the northern-summer period.
A male was collected here on July 20, 1922. It was in worn, non-breeding
plumage, with a renewal of the wing quills under way. Presumably such
examples, like other northern sea birds and shore birds taken in the Gulf of
Guayaquil during this same season, had been deterred from migrating toward
their usual breeding grounds by a failure of the internal glandular secretions to
function normally. Dr. Chapman has noted that the sex organs of all such
birds were in a dormant state.
My own specimens from Ecuador and northern Peru are in full winter
plumage, with white foreheads and speckled crowns. An example taken at
Talara on January 17, 1925, was just completing the moult of the remiges, all
of which had been replaced except the outermost primary, which was ragged
from wear. In Ecuadorian birds taken a month later, the wing moult had been
completed, but the new tail feathers had not yet grown to full length. The
bills of all of these birds were orange, the legs and feet black with orange soles.
The specimens entirely agree with examples taken by Beck at St. Thomas and
Santo Domingo, in the months of August and November, 1916.
The claw on the middle toe of this species shows a breaking down of the
flange, which looks like an incipient stage in the development of a pecten. The
same phenomenon is even more pronounced in the Inca Tern.
Gibson (1920, 74) reports the Royal Terns along the outer coast of the Prov-
ince of Buenos Aires during the month of March, sometimes apparently in
migration well out at sea, sometimes mingling with Trudeau's Terns and gulls
on the sandbars near Cape San Antonio. He states that its clear, shrill, short
cry distinguishes it from any other local species.
1140 OCEANIC BIRDS OF SOUTH AMERICA
On November 4, 1920, Wetmore (1926, 139) collected a male on the coast
south of Cape San Antonio, and subsequently saw many others along beaches of
the outer part of the Gulf of La Plata.
The effect of oceanic circulation upon avian distribution is well illustrated
by the above notes from both coasts of South America. Undoubtedly it is
Brazil Current influence which carries the Royal Tern to latitude 37° S., or
beyond, in Argentina, while the Humboldt Current blocks it at latitude 7° S.
in Peru.
In South America, as elsewhere, the food of the Royal Tern appears to consist
almost wholly of small fishes. Hallinan (1924, 306) and Gibson (1920, 74)
report the stomachs of specimens filled with fish or their scales and bones, in
the Bay of Panama and on the Atlantic coast of Buenos Aires, respectively.
The bird is often seen fishing in company with Brown Pelicans and other large
sea birds. It is said to rob the pelicans to some extent, and in northern Peru I
have seen a group pursuing even a man-o’-war bird. The Royal Tern when
fishing usually plunges from a much greater height above the sea than do the
smaller species of terns. For this reason it has earned the name of ‘‘Gannet-
striker’’ along parts of the coast of the United States.
CAYENNE TERN
Thalasseus eurygnatha
Sterna eurygnatha Saunders, 1876, Proc. Zodl. Soc. London, p. 654, fig. 1 (Santa Catharina, Brazil).
Names: Black-footed Tern. Previous to the date of the description of this species in 1876, and
subsequently through erroneous identification, this tern has been listed under the specific names
cayennensis, galericulata, and elegans.
Characters: Adults are identical in plumage with Thalasseus elegans, but the bill is lemon-
yellow, and the angle of the gonys is immediately below or very little in front of the anterior end
of the nostril. Total length, 444.5; wing, 307.3; tail, 165.1; exposed culmen, 68.6; tarsus, 27.9;
middle toe and claw, 30.5 mm. (Saunders, 1896, 85).
Young: Forehead, crown, and occiput white, the last, together with posterior portion of
crown, streaked with dull blackish; nape and post-ocular (supra-auricular) region dull black, the
feathers margined, more or less distinctly, with grayish white; hind neck, upper back, rump, and
upper tail coverts white, the rump more or less spotted with gray; scapulars and interscapulars
pale gray, indistinctly though rather broadly margined terminally with white, the tertials similar
but darker gray centrally; anterior lesser wing coverts (except along edge of wing) gray, the
feathers darker centrally, forming a well-defined broad stripe across anterior portion of wing;
posterior lesser coverts immaculate white; middle and greater coverts white basally, terminally,
and along edges, gray centrally; secondaries dark gray (more or less silvery or “‘frosted’’), tipped
and distally edged with white, their inner webs mostly white; primaries dark gray, ‘‘frosted”’
with lighter gray, margined terminally with white, their inner webs broadly edged with white,
except the longer (distal) quills; primary coverts similar but margined terminally with pale gray;
middle pair of rectrices pale gray (more whitish on inner webs), tipped and terminally edged with
white; outermost rectrices white to near tip, where gray and blackish, the intermediate rectrices
white proximally, gray and dusky distally and margined with white at tips; sides of head (beneath
eyes) and entire under parts, together with axillars and whole under surface of wing (except a
broad stripe of deep gray along shafts on inner webs of primaries) immaculate white.
Downy young: Grayish white, thinly streaked with dark gray on the crown, behind the eye,
and on the upper parts generally; under parts white; bill olivaceous; tarsi and toes brown, claws
lighter (Ridgway, 1919, 474).
CAYENNE: TERN 1141
The eggs seem to be similar to those of Thalasseus maximus but slightly smaller, measuring
60-64 x 43 mm. (von Ihering, 1900, 294).
Distribution: Caribbean and Atlantic coasts of South America from Colombia and Venezuela,
including the islands of Aruba, Margarita, Trinidad and Tobago, southward to Puerto Deseado,
Argentina. Breeds on the coast of Brazil.
The Cayenne Tern has a long range on the Caribbean and Atlantic coasts of
South America, but little is known about its habits or the extent of its breeding
area. The species was not collected during the Brewster-Sanford Expedition.
Clarke (1902, 258) and Cory (1909, 194) report this tern as common at Mar-
garita and Aruba Islands during May. Von Ihering (1900, 294; 1907, 41) has
recorded it from various parts of the Brazilian coast, and has described the eggs.
ELEGANT TERN
Thalasseus elegans
Sterna elegans Gambel, 1849, Proc. Acad. Nat. Sci., Phila., 4, 1848, p. 129 (Mazatlan, Sinaloa, Mexico).
Names: This species has also been listed under the specific name galericulata, besides which it
has been twice described from Chile, under the names gayi and comata.
Characters: A small, crested tern with a slender orange-red bill, the gonydeal angle of which is
far anterior to the nostril.
Adults in breeding plumage: Pileum, including occipital crest, nape, and upper half of lores,
uniform deep black; rest of head and neck, entire under parts, lower rump, upper tail coverts, and
tail immaculate pure white, the under parts more or less deeply suffused with eosine pink; back,
scapulars, upper rump, and wings plain pallid neutral gray; inner webs of primaries with a sharply
defined stripe of dark gray next to shaft, this color extending across tips and for a short distance
along edge; bill orange or reddish orange; iris dark brown; legs and feet black.
Adults in post-nuptial plumage: Similar to the above, but forehead and lores white; crown
white, spotted with dusky, only the occipital crest, nape, and sides of crown to and in front of
eye, uniform black (Ridgway, 1919, 472).
3 males from Lower California and Mazatlan: wing, 313-337 (324.7); tail, 165-178 (171.8);
exposed culmen, 59.6-69 (65.3); tarsus, 29.4-30.4 (29.9); middle toe and claw, 29.5-32.4 (30.8) mm.
Young: Pileum dull brownish black, nearly uniform on occiput (where the feathers are not
elongated nor lanceolate, but short and blended), the whole crown streaked with white; forehead
and lores white, finely streaked with blackish; hind neck, upper tail coverts, and under parts
white, the lower portion of the first with a few roundish spots of dusky; back, scapulars, and wing
coverts dull whitish, coarsely and irregularly spotted with dusky grayish brown, this forming
an almost uniform area on lesser wing covert region, the anterior border of which is white; secon-
daries dusky, margined terminally with white; primaries dark hoary gray, narrowly margined with
white, their inner webs mostly white but with a broad stripe along shaft and around tip dusky
gray; rectrices deep brownish gray becoming paler gray basally, their tips margined with white;
bill dull reddish or brownish; legs and feet dusky (Ridgway, 1919, 472).
Distribution: Breeds in Lower California and on islands in the Gulf of California. Winters
off the west coast of South America southward to Valdivia.
Except for two specimens taken at Callao and Chorrillos, Peru (Saunders,
1896, 85), nothing seems to be known about the Elegant Tern between its nest-
ing grounds in North America and its winter range along the coast of Chile.
Even as regards information from breeding stations at islands off both coasts
of Lower California, indeed, this beautiful bird is one of the least known of
terns. Little seems to have been learned about its habits, and the downy stage
of its plumage has apparently not yet been described.
1142 OCEANIC BIRDS OF SOUTH AMERICA
In Chile specimens have been collected at Arica, Iquique, Coquimbo, Val-
paraiso, and Corral, between the months of September and February. Hellmayr
(1932, 407) reports that birds in the white-fronted winter garb have been found
to be fairly common in the Bay of Corral, between November and February,
and that immature examples have been taken at Corral, and at Vifia del Mar,
near Valparaiso.
CABOT’S TERN
Thalasseus sandvicensis acuflavidus
Sterna acuflavida Cabot, 1848, Proc. Boston Soc. Nat. Hist., 2, 1847, p. 257 (Tancah, Yucatan).
Names: Also called Sandwich Tern; other specific names under which the species has been
listed are cantiacus and boysii.
Characters: The only American crested tern with a black bill, which is usually tipped with
yellowish or whitish.
Adults in breeding plumage: Pileum, including occipital crest, nape, and upper half of lores
uniform deep black; upper parts pallid neutral gray to nearly pale neutral gray, the outer webs of
primaries slightly darker, with a silvery or hoary cast; inner webs of primaries mostly white,
with a broad stripe of dark gray along shafts; hind neck, entire under parts (including axillars
and under wing coverts), rump, upper tail coverts, and tail immaculate pure white; bill black,
tipped more or less extensively with yellow or whitish; iris dark brown; legs and feet black.
Adults in northern-hemisphere winter: Similar to the breeding (?) plumage but forehead and
lores white, the crown streaked with black and white, and black occipital feathers faintly tipped
with white (Ridgway, 1919, 476).
4 males and females from the coast of Brazil: wing, 276-294 (282.5); tail, 106.9-119.5 (113.7);
exposed culmen, 47.5-53.5 (50.9); tarsus, 25.3-27.3 (26.1); middle toe and claw, 26-28.1 (27.4) mm.
Young: Pileum, nape, and upper half of lores dull blackish or dusky, irregularly intermixed
with dull whitish, especially on crown, which is coarsely spotted; occipital feathers short and
blended; rest of upper parts, including rump, upper tail coverts, and tail pale gray, coarsely and
irregularly spotted with dull blackish or brownish black; wings, except smaller coverts, as in
adults; rectrices becoming darker gray terminally, where irregularly spotted, or with hastate spots,
of dusky or blackish; under parts immaculate white; bill dusky or dull blackish, scarcely or at
least not abruptly, paler at tip (Ridgway, 1919, 476).
Distribution: Breeds from the southern Atlantic and Gulf coasts of the United States to the
Bahamas, West Indies, and the coast of British Honduras. Winters from Florida and the Bahamas
to the Caribbean and Atlantic coasts of South America between Colombia and Brazil.
South of Middle America, Cabot’s Tern appears to belong exclusively to the
Atlantic coast of the New World, where it has been taken as far southward as
Sao Paulo and Iguapé, Brazil (von Ihering, 1907, 40). A few are said to remain
on the Brazilian coast throughout the northern summer, and an example has
been recorded from Rio de Janeiro in August (Bent, 1921, 227). A male and
two females collected with other terns off Bahia, on June 30, 1916, by Mr.
Beck, were apparently birds which were not bound back toward their breeding
grounds, for the gonads of all three were undeveloped. In these specimens the
bills were black with a yellow tip, and the feet black with yellow soles. One of
the females may have been a yearling, for its bill is smaller than those of birds
in comparable plumage from Florida and Texas.
Cabot's Tern is a highly gregarious bird, mingling not only with its own kind
but also with other species such as the larger Royal Tern. At Alacran Reef,
CABOT’S TERN 1143
in the Gulf of Mexico, it has been found in late May among great numbers of
Sooty Terns (Kennedy, 1914, 42).
So little is known about the longevity of sea birds that a recent note relating
to Thalasseus sandvicensis sandvicensis, the Old-World representative of Cabot’s
Tern, is of interest. A bird of this race banded in Cumberland, England, in
June, 1917, was recovered in southwestern Africa nearly fourteen years later
(Flower, 1931, 48).
INCA TERN
Larosterna inca
Sterna Inca Lesson, Voy. da la ‘Coquille,’ Zodl., Atlas, livr. 3, pl. 47 (Callao, Peru).
Names: Generally known in Peruas ‘‘Zarcillo’’ but on some parts of the coast called ‘‘Aromito’’;
a common name in Chile is ‘‘Monja."’ The Inca Tern has been described under the specific name
mystacalis and through misidentification has been listed also under the specific name stolida.
Characters: The moustache-like tufts of feathers projecting from the angle of the mouth in
this gray-bodied, red-billed tern distinguish it from all other species. The tufts are white in adult
birds and gray in fledgling young.
Adults in breeding plumage: Dark bluish slate color, lighter on the throat and under wing
coverts; primaries and outer rectrices brownish black; the four outermost primaries edged with
white; secondaries mostly broadly tipped with white; a white moustachial stripe from the angle
of the mouth terminating in a tuft of about ten slender plumes which cling together and curve
backward, downward and outward from the cheek to a length of 50 mm. or more; wing much
more rounded than in most terns; tail moderately forked, the outermost rectrix being only slightly
longer than the second; iris brown; fleshy wattles at the angle of the mouth bright yellow; bill
dragon’s-blood red; legs and feet red of a slightly paler hue.
8 males from coast of Peru: wing, 271-291 (281.3); tail, 129.4-133.8 (132.2); exposed culmen,
43.4-49.2 (45.6); tarsus, 22.5-24.8 (23.5); middle toe and claw, 29.2-32.4 (30.7) mm.
5 females from coast of Peru: wing, 263-280 (270.6); tail, 117.5-138.5 (128.3); exposed culmen,
42-47.5 (44); tarsus, 21.9-23.3 (22.8); middle toe and claw, 29.1-31.1 (28.9) mm.
Immature: Browner than adults, with a bill of blackish horn-color, which gradually changes
to red, and with pale feet; the plumes of the moustache and the stripe from the bill are of the same
ashy brown color as the surrounding plumage. In fledgling birds the moustache is indicated only
by a faint gray line, with very short free terminal plumes.
A downy chick from San Gallan Island, Peru, July 2, is covered with rather nondescript pur-
plish gray down, somewhat lighter on the belly than on the dorsal surface. Only on the head
are there a few dark spots reminiscent of the general pattern of gull and tern plumage.
Eggs: One or two ina set, usually ovate or elongate-ovate and exceedingly variable in color;
a common ground color is light buff, this being overlaid with heavy splashes and blotches of
mummy-brown and other shades of brown; the concentration of markings is usually heaviest around
the larger end where it sometimes forms a ring; occasionally eggs have a ground color of pale blue
with or without superimposed spots and blotches. In all of these respects they are typically tern-like.
Measurements of two sets of one egg and one of two obtained on islands off the coast of central
Peru during June and July are as follows: 51 x 36.8; 58.1 x 37.2; 52.2x 38.1 and 53.5x37.2mm.
Distribution: Coasts of Peru and Chile, from Lobos de Tierra Island and Point Aguja southward
to Coquimbo and casually to Valparaiso and Corral. The breeding range probably extends from
the Lobos Islands southward to Pelican Rock off Coquimbo.
The coral-billed Inca Tern is the most outstanding example of an endemic
bird in the Humboldt Current region. So distinct is it from its closest relatives
elsewhere that no one knows just what these may be. It is present in enormous
numbers on rocky shores and islets throughout the length of the desert littoral
1144 OCEANIC BIRDS OF SOUTH AMERICA
of Peru and northern Chile. Not only is it familiar to visitors to lonely islands,
but equally so to residents of the busiest seaports. Its commonest names refer
to characteristics of its striking plumage: thus “‘Zarcillo’’ likens the white,
corkscrewed plumes to pendent earrings, and “‘Monja’’ connotes a fancied
resemblance to a gray-robed nun with starched white linen at her throat; the
meaning of ‘‘Aromito’’ I have never learned.
It is altogether a most pleasing bird in its grace of form and movement, as well as in its strikingly
neat and even dandified appearance. The soft dark blue of the plumage is effectively varied by the
crimson of bill and feet, the white margin of the wings, the yellow flaps at the gape of jaws, and
the showy “‘earrings’’ (Coker, 1919, 460).
In general, the Inca Tern inhabits the same kind of rocky coasts as the sea-
lion, and the two are very frequently seen together. During the Brewster-
Sanford Expedition and the course of my own field work in Peru, the species
was observed, apparently in residence at Salaverry, the Guafiape Islands, Palo-
minos Rocks, Mazorca Island, Pescadores Islands, Ancén, Callao, San Lorenzo
Island, Fronton Island, Asia Island, the Chincha Islands, San Gallan Island,
Santa Rosa, Vieja and other islands in Independencia Bay, and at Mollendo.
Hellmayr (1932, 404) alleges that it breeds as far north as Macabi Island.
Furthermore, Beck observed one just off Hormigas de Afuera, 67 kilometers
west of Callao, where MacFarlane (1887, 207) long ago recorded it as nesting.
This is perhaps the most seaward record for a species which is confined entirely
to the zone of cool, upwelling waters of the Humboldt Current.
Centers of particular abundance of these terns, as noted during the field work
of Mr. Beck and myself, include the Pescadores Islands during December, April,
and May; Asia Island, the Chinchas, and San Gallan. Movements of the birds
seem to be more or less sporadic, and are doubtless determined by conditions in
the Humboldt Current that affect their food resources. MacFarlane and other
observers have attributed the sudden appearance of great numbers of Inca Terns
in the harbor of Callao or elsewhere as due to completion of the breeding season
and a consequent migratory trek. We know now, however, that egg-deposition
and the rearing of the young go on throughout the year. There may well be a
peak of productiveness during the southern-hemisphere spring, but a large
proportion of the birds have eggs and young chicks in June and July, which is
midwinter. I believe, therefore, that the sudden appearance of flocks in bays
or roadsteads, where none had been observed during preceding days, is due to
a concentration of birds from neighboring islands in pursuit of food. For
example, on October 25, 1919, I saw about 500 Inca Terns attracted very quickly
when Peruvian Indian fishermen were engaged in illegal dynamiting of fish
along the cliffy coasts of North Chincha Island. During late April, 1913, Beck
observed aggregations, which he estimated to contain 5000 or more of these
birds, in the vicinity of some of the islets off Ancdn. My own notes, added to
those of Messrs. Beck and Jaques, lead me to the conclusion that the Inca Terns
may be more abundant at the Pescadores Islands than on almost any other part
of the Peruvian coast.
At North Chincha Island I obtained eggs during December, 1919. Beck
INCA TERN 1145
collected several at Fronton, off Callao, on June 3, and others at San Gallan,
off Pisco, in July. At the last island he found eggs and young in all stages of
development. On December 28, 1919, at Palominos Rocks, full-fledged young
made up more than half the local population of these birds, although there
were still fresh eggs in some of the rock caverns.
The Inca Terns nest in niches, hollows, or burrows, some of which they
make or enlarge themselves. More often, however, interstices in a scree, a
natural hollow in a guano-covered slope, or the burrow of such a bird as a diving
petrel, furnish the necessary site. At San Gallan Island, for example, Beck
located eggs and chicks both in rock heaps close to the shore and in diving petrel
burrows at a considerable distance inland. At Independencia Bay I found that
the Inca Terns even made use of the entrances to penguin burrows, scratching
out a little chamber for themselves just inside the threshold of the dwelling
of their hosts.
The presence or abundance of Turkey Vultures at any Peruvian guano island
appears to have more or less to do with the degree to which the Inca Tern nests
are concealed, for the vultures are inveterate nest-robbers and quickly gobble
up eggs left within sight or within easy reach. Furthermore, the Inca Terns
sometimes meet with insufferable competition from the Guanays or Peruvian
Cormorants. When the latter cover a hillside in their wonted manner, the terns
are forced to abandon the territory, since the constant treading and milling
about of the larger birds tends to break down the entrances to the tern nests,
besides which they become filled up with guano. At Asia Island I noted particu-
larly that the Inca Terns inhabited all the slopes that were not occupied by
the Guanays, and also the steep sides of a gloomy chasm which cleaves the
island well toward its center. Some of the tern burrows were deep and compli-
cated, while in others the eggs could be seen lying within 20 to 30 centimeters
of the entrance. At Asia Island, as at the Pescadores, I should say that the
Zarcillo population was large enough to make the species of appreciable im-
portance as a guano bird.
Coker’s (1919, 461) remarks on the nesting of the species are as follows:
The breeding places of zarcillos are found on many islands; generally they were observed to
use the trenches or other places where the surface crust had been broken away in guano extraction,
and where the nests could readily be concealed by excavating little tunnels in the bank. Nests
with all stages of eggs and young were observed at the Chincha Islands (North Island) in June,
1907. One of the most populous breeding places was the Isla Asia visited in August of the same
year. I have no record of nests observed in the summer season although doubtless there is little
interruption of the breeding season.
As a result of Beck's field work, and of my own, the American Museum has
an excellent series of Inca Terns, illustrating all states of growth. The downy
stage of the young is followed by a nearly uniform plumage, dusky brown on
the dorsal surface and dusky gray below, the scapulars and lesser coverts being
tipped with white. In their later stages, young birds resemble immature
examples of the Sooty Tern (Sterna fuscata), although their wing-linings are
dark instead of whitish, and moustache-like plumes are present even though
1146 OCEANIC BIRDS OF SOUTH AMERICA
inconspicuously gray in color. The slaty plumage of the adult type is acquired
by a post-juvenal moult which involves all the feathers except the quills of
wing and tail.
On the claw of the middle toe, I find, the Inca Tern has a flange which re-
sembles a pecten in rudiment. This organ, well known in herons, frigate-birds,
etc., has not been reported among the Laridae. The flange of the Inca Tern is
irregularly serrate toward its base, while on the distal half the processes take
on the form of teeth of variable width. Most specimens show ten or twelve
of these, and in the interstices there are usually fine fragments of feathers result-
ing from the scratching and combing for which the structure is used.
The Inca Terns are very inquisitive creatures, circling rapidly about, now
and then making startling dashes toward one’s head, swerving aside just before
they strike. Coker suggests that this habit is correlated with the pursuit of
other birds, perhaps causing the latter to drop their food, which the alert terns
can then appropriate. At any rate, they are quick to take advantage of the
spoils of any predator. Several times, near various guano islands, I have seen
Turkey Vultures, their guano-spattered backs showing where they had been
feeding, shot at by the government guardians. If such vultures were not killed
instantly, they would disgorge into the water, whereupon flocks of Inca Terns
seemed always at hand to scurry to the surface below in quest of what the
vulture had unloaded. Moreover, the Inca Terns seem always to be hovering
about the head of a rising sea-lion. When the animal appears, mouthing and
tossing its fish, the terns are like a cloud of flies, sometimes dropping almost
into the seal’s jaws for morsels. I have seen them fluttering in the same manner
above rising humpback whales in the Humboldt Current.
The Inca Tern’s mode of flight has little in common with that of most of its
relatives, for its wing-beats are rapid and fluttering, and it usually hovers near
the surface of the water before stooping or making shallow dives. Flocks of
the birds show a very strong tendency toward simultaneous action. I have seen
groups sitting on rocks beneath the cliffs launch suddenly into flight and, after
a short period of circling, return to the same spot, only to repeat the performance
a few moments later. Coker writes:
In flight it apparently delights in sharp curves, quick reverses of direction, or sudden drops
with webbed feet outspread. The forked tail presents a variety of forms in these maneuvers, now
widespread and fan-shaped losing all trace of the fork, now closed in swallow-tail effect, or, again,
so snugly closed as to obscure the forked form entirely.
The call of the Inca Tern is plaintive and petulant, without the harsh tone
in the cry of the ‘‘Terrecle’’ (Sterna hirundinacea). Coker likened it to the voice
of a young kitten.
The food for which the Inca Tern plunges, if it cannot obtain it in scraps
from the banquets of other organisms, consists of small fish. The alimentary
tracts of two examples I collected at the Chincha Islands during October
were well filled with remains of anchovies (Engraulidae). One of them
contained six or more of the latter, and the other a few feathers and a bird-
tick (Ornithodorus).
PRE PACIFIC TERNLETS 1147
Tue Paciric TERNLETS OR Gray Noppies
The latest list of these exquisite and diminutive terns is that of Peters (1934,
345) who treats them as seven subspecies of the typical form, Procelsterna cerulea,
which was described from Christmas Island, 2° north of the equator in mid-
Pacific. In an accompanying footnote Peters states that the forms of this
allegedly monotypic genus are much in need of revision and that his arrange-
ment is merely tentative.
Disregarding for the moment the several subspecific names, it is apparent
that the ternlets, from whatever source in the Pacific, are divisible at sight into
two groups, of which one is made up of birds that may be called ‘‘blue,’’ and
the other of birds that are “‘gray."’ I find, furthermore, that this distinction
is correlated with a zonal type of distribution, all of the blue birds inhabiting
tropical islands to northward of about latitude 25° S., while the gray birds
belong to islands south of the 25th parallel and close to the Sub-Tropical Con-
vergence. Finally, the Gray Ternlets are of uniformly larger size than the Blue
Ternlets, the relationship presenting another good illustration of Bergmann’s
law (cf. p. 358).
For such reasons I hold that the Blue and the Gray Ternlets constitute dis-
tinct species, each of which breaks up into a number of subspecies. The former
is Procelsterna cerulea, of the Tropical Zone of surface water, with representatives
at the Line Islands, the Phoenix and Ellice groups, the Samoan, Society, Mar-
quesas, and Tuamotu Archipelagoes, and other mid-Pacific localities. The
second species is Procelsterna albivitta, of the Sub-Tropical Zone. It was origi-
nally described from Lord Howe Island, and it is represented at Norfolk Island,
the Kermadec group, the Australs, Henderson, Ducie, Easter, San Felix, and
San Ambrosio Islands, all of which are far on the polar side of the Tropical
Convergence. It is only at San Felix and San Ambrosio that the Gray Ternlets
enter the field of this book. The resident form has been described somewhat
inadequately by Mathews. Final determination of its status must await the
working up of its relatives from many South Pacific islands, but for the present
I shall make use of Mathews's subspecific name, and point out the slight average
difference in size between the ternlets of San Felix and those of the least distant
islands of southern Polynesia. The form inhabiting Easter Island has already
been given the subspecific name skottsbergii by Lonnberg (1921, 20), but its
taxonomic relationships cannot be said to be more than sketchily known.
The two sexes of the Gray Ternlet seem to be of approximately the same
size. The following table compares the average dimensions of San Felix birds
with those of ternlets from southeastern Polynesia.
Wing Tail |Exposed| Tarsus |Middle toe
culmen and claw
60 and 39 from San Felix Island .... . 204.4 101.9 ah g) 26.4 35.5 mm.
8c and 39 from the islands of Henderson,
Ducie, Easter, Ravaivai, Rapa, and Bass
ROCKS. Ste ene ene tenes ree 200.5 100.5 26.3 25 33.5
1148 OCEANIC BIRDS OF SOUTH AMERICA
SAN AMBROSIO GRAY TERNLET
Procelsterna albivitta imitatrix
Procelsterna cerulea imitatrix Mathews, 1912, Birds Australia, 2, p. 431 (San Ambrosio Island, Chile).
The typical race of this species is as follows:
Procelsterna albivitta Bonaparte, 1856, Compt. Rend. Acad. Sci. Paris. 42, p. 773 (Lord Howe Island).
Names: Gray Noddy. The species appears in the literature under the names pelecanoides,
cinereus, and also under various synonyms for the species cerulea, which include parvulus, plumbeus,
teretirostris, and tephrodes.
Characters: A small, long-legged tern with large feet, gray back, wings, and tail, and grayish
white head and ventral surface.
Adults (sexes alike): Head and under parts gray-white, a ring of black feathers around the
anterior part of the eye, the hinder part of both lids being covered with white feathers; back and
scapulars pale or light neutral gray, the wings and tail somewhat darker, tending toward deep
neutral gray at their tips; lesser coverts and tertials broadly edged with white, particularly on the
outer webs of the feathers; inner webs of two outermost primaries whitish on their inner halves;
shafts of quills brownish dorsally, and white in ventral aspect. Iris brown; bill black; legs and
feet brownish black with the webs flesh color or yellowish. Inside of mouth yellow.
3 males: wing, 202-210 (207); tail, 98-109 (104.7); exposed culmen, 26.9-28.5 (27.6); tarsus,
25.4-27.5 (26.8); middle toe and claw, 33.9-37 (35.6) mm.
6 females: wing, 195-211 (203); tail, 95.6-106.3 (100.8); exposed culmen, 26.6-27.5 (27);
tarsus, 24.8-27.9 (26.2); middle toe and claw, 34.4-37.5 (5.5) mm.
Young birds (from Rapa Island, Austral group) differ from adults in being slightly brownish
on the back, and in having the pileum, chin, and throat streaked with dusky feathers. Downy
young are smoky gray, lightest in hue on the cheeks, nape, and ventral surface.
Eggs of the San Felix-San Ambrosio race have not been taken. Mathews describes an example,
presumably from Norfolk Island, as ‘‘ground-colour stone, with underlying spots of grey sparingly
distributed, and fewer spots of chestnut-brown; axis 42 mm., diameter 30.""
Distribution: The subspecies, if valid, is presumably confined to the islands of San Felix and
San Ambrosio. The species a/bivitta is a bird of the southern Pacific Sub-Tropical Zone, occupying
islands lying between the tropic of Capricorn and latitude 32° S.
The first specimen of the Gray Ternlet of San Felix and San Ambrosio to be
described was collected by Lieutenant Gunn, of the Royal Navy, during 1880,
and was reported upon by Tristram (1881, 177). During the cruise of the
‘Alerte,’ however, Coppinger had already obtained an example at San Ambrosio
in July, 1879, and this subsequently found its way into the British Museum
(Saunders, 1896, 136).
On the occasion of the visit of the yacht ‘Zaca’ to these islands, the ternlets
were found to be common, and on February 18, 1935, Chapin collected a series
of nine non-breeding adults for the American Museum. The birds were observed
flying in flocks about the bases of the cliffs, perching on low, projecting rocks,
and resting on the surface of the water. They were in process of moult, and
several of our specimens show a mixture of old and new wing and tail quills.
Their stomachs were mostly filled with small shrimp-like crustaceans about
10 millimeters in length. One female is marked as having contained “‘hundreds”’
of these. Gray Ternlets shot at Rapa, Ducie, and Easter Islands, earlier during
the course of the same cruise, contained small cephalopod mandibles, remains
of crustaceans, and tiny fish with silvery eyes, resembling larval eels.
SANFC AM BROSIO GRAY TERNLET 1149
On islands in the easterly part of the range of the species as a whole, this
little tern is described as laying its single very thin-shelled and delicate egg on
bare rocky ledges, at altitudes between sea level and 600 meters or more. The
birds are not migratory, but remain at their breeding grounds throughout the
year. In nesting behavior they are not essentially colonial, though the nature
of the required sites sometimes leads to a high concentration of breeding birds.
The season of reproduction is in the southern spring, between September and
January. In this respect the Gray Ternlet differs characteristically from the
smaller and darker tropical species (Procelsterna cerulea), which seems to have
an all-year breeding season.
Cheeseman (1891, 222) states that at Meyer Island of the Kermadec group,
where the eggs of the Gray Ternlet are laid in October,
. almost every ledge on the cliffs near the landing-place was occupied by these birds,
which watched our proceedings with the greatest curiosity. Small flocks of them would every
now and then leave their resting-places, fly backwards and forwards over our heads, noisily
screaming all the time, and then return to their quarters, to be quickly imitated by another party.
They were quite tame, allowing us to approach within a few feet.
Tue Noppy Terns, Genus ANoUs
The noddies are of two types, one brown-plumaged, the other smaller and
black-plumaged. The brown bird is Anows stolidus, which has a number of
subspecies in different oceans. Of the black noddies there are two species, of
which Anouis minutus, sometimes known by the generic names Micranods or
Megalopterus, has Atlantic and Pacific races in the South American region, and
others elsewhere. ;
Both the species of noddies within our field are of pan-tropical distribution,
but both reach the border of sub-antarctic surface water at the Tristan da Cunha
group in the South Atlantic. They thus have a zonally broader range than
either the Fairy Terns (Gygis) or the Sooty Terns (Sterna fuscata). Like both
the latter, however, they reach considerably higher latitudes in the equable
middle zones of the southern or water hemisphere than they do in the northern
or continental hemisphere.
It is very interesting to note that the noddies have access to Tristan da
Cunha, so to speak, because their annual migration to and fro is correlated with
seasonal changes in the temperature of the surface waters about these islands.
Along the west coast of South America, however, to southward of the equator,
the Humboldt Current interposes between the continent and the warm outlying
water a low-temperature barrier that does not greatly fluctuate with either
season or latitude. It is for such reasons that noddies and Fairy Terns are un-
known along the so-called tropical Pacific coast of South America to southward
of the Galapagos Islands. Neither do Sooty Terns breed within the area,
although they have been known errantly to fly into it. Just outside this zone,
in waters close to the rather indefinite Sub-Tropical Convergence of the eastern
South Pacific, the Brown Noddy has established itself as a resident at the little
island of San Felix.
1150 OCEANIC BIRDS OF SOUTH AMERICA
BROWN NODDY
Anois stolidus stolidus
Sterna stolida Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 137 (“Americae pelago’’ = West Indies).
Names: Noddy Tern; Wood Pigeon at Tristan da Cunha. In the bulk of the literature the
species is listed under its correct specific name, but synonyms include niger, leucoceps, and superctliosus.
Characters: A tern of uniform dusky or brownish coloration, the forehead sometimes whitish.
Adults (sexes alike): General color plain deep sooty brown (nearly clove-brown), the under
parts somewhat lighter (nearly sepia), paler and more grayish on hind neck, where passing,
anteriorly, through pale gray into white or grayish white on forehead and superciliary region; a
bar or narrow crescent of white on lower eyelid; lores and narrow space immediately above eye
black or sooty black, in abrupt and strong contrast with the white or grayish white of forehead and
superciliary region; the sides of head and neck, chin, and throat sooty brownish but of a more
grayish cast (sometimes nearly dark plumbeous, especially in fresh plumage) than the general
color; remiges and primary coverts darker sooty brown, the primaries and their coverts approaching
sooty black; axillars and under wing coverts deep brownish gray; bill black; iris dark brown; legs
and feet brownish (said to be dull brownish red or reddish brown, with ochraceous webs, in life)
(Ridgway, 1919, 546).
12 males from the West Indies, Fernando Noronha, Bahia (Brazil), Ascension, South Trinidad
and St. Helena: wing, 261-297 (269.8); tail, 130-154.4 (138.6); exposed culmen, 38.8-47.2 (43.2);
tarsus, 24.3-27 (25.8); middle toe and claw, 35.1-39.1 G7.2) mm.
8 females from the West Indies, Bahia, Fernando Noronha and Ascension: wing, 261-275
(266.8); tail, 121.5-146.2 (136.7); exposed culmen, 39.7-44.2 (42.4); tarsus, 24.2-25.3 (24.7);
middle toe and claw, 35-38.7 (36.6) mm.
Measurements in the flesh of a dozen specimens of both sexes from Fernando Noronha, South
Trinidad, and St. Helena, were: length, 419-457; wing-spread, 815-876, average 838 mm.
Young: Essentially like adults but general color lighter sooty brown and pileum much less
distinctly gray, with white, or very pale gray restricted to a narrow superciliary line, sometimes
continued around lateral and anterior edges of forehead.
Downy young: Immaculate dull grayish white to pale brownish gray or even sooty brown,
paler (sometimes dull white) on abdomen (Ridgway, 1919, 546).
Eggs: The single egg is ovate or slightly elliptical-ovate in shape. The shell is thin, smooth,
and without lustre. The ground color varies but slightly, from ‘‘pale-pinkish buff’’ to ‘‘cartridge
buff.’ It is sparingly spotted with small spots or dots, usually more thickly at the larger end, with
at least two distinct colors. The underlying spots are of various pale shades of lilac or lavender
and the overlying, more conspicuous, spots are of bright shades of deep reddish brown. Some of
the brown spots seem to be superimposed over the lilac spots or blended with them. The eggs can
be readily distinguished from those of the Sooty Tern by being much less heavily spotted. The
measurements of 44 eggs, in the United States National Museum, average 52 x 35 mm.; the eggs
showing the four extremes measure 58 x 37, 54 x 37.5, 49.5 x 35.5, and 51 x 33 mm. (Bent, 1921,
306).
Distribution: Breeds on small islands from the Bahamas and Florida Keys, southward through
the Gulf of Mexico and the Caribbean Sea and the tropical and sub-tropical Atlantic; breeding
stations in the latter ocean include St. Paul Rocks, Fernando Noronha, Rocas Reef, Ascension,
St. Helena, South Trinidad, and the three islands of the Tristan da Cunha group; it is recorded as
at least a visitor to Gough Island.
The distribution of the Brown Noddy in the Atlantic is highly remarkable,
for the bird breeds at all suitable islands from the Bahamas, and the northern-
most West India islands, southward to those of the Tristan da Cunha group,
beyond the 37th parallel of south latitude. Both the Brown and the Black
Noddy (Anois minutus) are, in fact, found together at Tristan, and I suspect
that the two have been much confused by visitors who have written about
BROWN NODDY 1151
them. Only the Black Noddy is here given to nesting in trees, and probably it
is this smaller species which is the true “Wood Pigeon"’ of Tristan. The Brown
Noddy breeds rather on bare rocks, such as those called the Hardies, just off
the coast of Tristan da Cunha, from where Mathews (1932, 45) has recently
reported eggs, taken during November of three different years, which agree in
measurements and appearance with those of the same species from the West
Indies.
Saunders (1881, 137) writes of a Brown Noddy shot on Inaccessible Island,
on October 16, 1873, which he found to be absolutely identical with birds
from the Dry Tortugas, Florida. He distinguished this specimen, of course,
from examples of the Black Noddy taken at the same island, on the same date,
by members of the ‘Challenger’ expedition. Campbell (1877, 72) also observed
noddies swarming inside a large cave on Nightingale Island, although he saw
no nests.
There can be no doubt about Captain Comer’s record of the Brown Noddy
from Gough Island, for he not only brought home one skin but observed many
of the birds (Verrill, 1895, 452). Wilkins (1923, 496) has more recently re-
ported seeing at Gough a tern resembling this species. The same author says
that at Tristan da Cunha the migrating noddies arrive in September, lay their
eggs in November, but leave the islands altogether for the winter season.
According to Barrow (1910, 275), the extreme absolute temperatures at sea
level on Tristan da Cunha, during the years 1908 and 1909, were 3.8° C. (August
16) and 25.4° C. (March 14). Since the noddies arrive soon after the period of
lowest temperatures for the year, we may doubtless take the first of these
thermometer readings as approximately the minimum which Brown Noddies
will tolerate at a breeding station.
Regarding the status of this species at other South Atlantic islands, Meliss
(1875, 98) states that it is one of the most abundant birds at St. Helena, where
it inhabits principally the ledges of outlying islands such as Egg Islet. At
Ascension it breeds on numerous rocky holms off the coast (Penrose, 1879, 280),
and Wilkins (1923, 510) found it nesting side by side with the boobies on
Boatswain-bird Island, on August 3, 1922, at which time the noddies had eggs
but no young. Moseley (1879, 563) reports it breeding at Ascension during
March and April, but the nature of his remarks leads me to suspect that he
may be referring to the Black Noddy. Simmons (1927, 72) discovered about
1200 pairs nesting at New Moon Cay, Rocas Reef, during April, while many
visitors to Fernando Noronha have found it a common resident.
I judge that at South Trinidad the Brown Noddy is migratory, more or less
as it is at Tristan da Cunha. On April 8, 1914, I found enormous numbers in
the waters about South Trinidad, and even captured by hand, and banded, four
of the birds as they hovered curiously about our whaleboat or alighted upon
our heads and shoulders. Nicoll (1906, 670) also found these terns abundant
and breeding on the occasion of his landing in January, 1906. Since none was
collected during the visits of earlier expeditions in August, and since the ‘Dis-
covery’ naturalists found noddies scarce in September, I conclude that the
1152 OCEANIC BIRDS OF SOUTH AMERICA
species is to be found at South Trinidad chiefly during the season of southern
summer. It is not unlikely that a migration takes the birds to distant parts of
the sea between the months of May and December. The further inference is
that only the noddies of sub-tropical, or even cooler, regions make a collective,
universal, exodus migration, a matter concerning which I shall give additional
data below.
Since noddies from all the sub-tropical South Atlantic islands, as well as
those from the Tortugas and the West Indies, are known to migrate away from
their nesting grounds for a part of each year, the dearth of pelagic records seems
very extraordinary. Indeed, the whereabouts of errant noddy and Sooty Terns
is one of the great unsolved mysteries of the sea, the more so because it is certain
that these birds rarely swim or rest upon the surface. Of pelagic records in the
Atlantic I find, however, a few. Peale (1848, 284), who remarks that the
presence of the noddy is no indication of the vicinity of land, captured a bird
which was attracted on board his ship at night, during the United States
Exploring Expedition, on the equator in longitude 17° 44’ W., a point about
equally far from Ascension, St. Paul Rocks and the coast of Africa. During
the cruise of the ‘Novara,’ large numbers of noddies were seen, and a female
was captured, on July 18, 1857, in latitude 7° 18’ N., longitude 29° 50’ W..,
which is almost equidistant from St. Paul Rocks and the Cape Verde Islands
(Pelzeln, 1869, 155). Buller (1905, 162) reports another that came on ship-
board on March 24, in latitude 29° 25’ S., longitude 45° 53’ W., a point south-
west of Santa Catharina Island, Brazil; and Goeldi (1894, 585) records the species
as a not infrequent visitor to the coasts between Rio Grande do Sul and Maran-
hao. During the course of the Brewster-Sanford Expedition, Beck, in fact,
collected many examples off Bahia during April, 1916. On April 15, when
they were first reported in his journal, he observed 200 or more among terns of
other species inside Barra Point; all the birds were following shoals of fish
which were entering the bay with the rising tide. Most of Beck's Bahia speci-
mens appear to be immature, with ‘slender bills and with whitish feathers just
coming into the crown. Adult examples are in non-breeding or “‘winter”’
plumage, with a moult of wing and tail feathers under way, the new quills
contrasting with the worn and faded body plumage. In other respects they
do not differ from birds collected by Beck in the West Indies during August
of the same year.
As inferred above, there are tropical localities at which the Brown Noddies
may be found breeding during every month in the year. Even under such cir-
cumstances, however, it is likely that there is at any one time a division of the
population into birds at home and birds away at sea. A parallel might be
drawn between this type of migration and the shedding of the leaves by many
trees of the humid tropics. Thus the simultaneous seasonal departure of all the
noddies from the Dry Tortugas, and the seasonal stripping of deciduous trees
in the temperate zone, are both conspicuous phenomena. But the same respec-
tive processes go on, though continuously and less obviously, among the tropical
noddies and trees. Certainly at St. Paul Rocks the available surface would be
BROWN NODDY 1153
insufficient to accommodate all the noddies that nest there at one time or another
each year. At this tiny haven, which projects barely above the surface of the
Atlantic, eggs and chicks have been found in February by the ‘Beagle’ party,
in May and December by the ‘Terror,’ in August by the ‘Challenger,’ in Novem-
ber by the ‘Quest,’ and in December by the ‘Valhalla.’ There can, therefore,
be no doubt that the breeding season is constant and uninterrupted.
A number of visitors, including even Darwin, have confused the Brown and
Black Noddies at St. Paul Rocks, attributing the specific difference in the nest-
ing habits of these two kinds of terns to a competitive struggle for nesting sites
among the members of a single species. The Black Noddy makes a bracket-like
nest against a sloping or upright surface, while the Brown Noddy, according
to Nicoll (1904, 36), mostly lays its egg upon the bare rock at this locality.
Elsewhere, the Brown Noddies may in some instances build fairly elaborate
nest structures and may even select trees, as well as shrubs, as sites; but in any
event they use little or no wet seaweed, the favorite nest material of Anois
minutus. The principal colony of the Brown Noddies of St. Paul Rocks is at
the base of Booby Hill, the high point of the islets. I suspect that even Wilkins
(1923, 475) confused the nests of the two species at this locality for, although
he clearly describes the Brown Noddy, and states that eggs and young were
found in slight depressions among the broken rocks, without any nest-lining
beneath them, he refers also to large, built-up nests of guano and seaweed,
which doubtless belonged to the lesser species. Wilkins reports, too, that the
abundant land crabs were constantly crawling within touching distance of the
young noddies without molesting them, nor were the birds showing any con-
cern. Probably the greater part of the normal food of these crustaceans com-
prises such offal as fish discarded by the noddies.
As soon as we transfer the field of our attention to the belt of ocean between
10° and 25° of north latitude, a zone in which there are definite seasons of
temperature, rainfall, trade-wind rhythm, or all three, we find that the physio-
logical cycle of the resident noddies likewise becomes rhythmic, in tune with
the meteorology. Within this zone, furthermore, the breeding range of the
noddy and of other tropical terns becomes shifted entirely to the Antillean side
of the Atlantic. The birds are absent, for example, from the Cape Verde Islands
which, from a superficial point of view, might seem to be admirably adapted
to them. I have shown elsewhere, however, that such distribution can be
correlated closely with the course of the Atlantic isotherms of surface water
for the northern-hemisphere spring months (Murphy, 1924, 230). The tropical
terns nest only to southward of the isotherm of about 26°’C. for the month of
June, while the northern or holarctic terns nest chiefly to northward of the
isotherm of 21° C. for the same month. The West Indies and Bahamas lie
equatorward of the first mentioned of these lines, while the Cape Verde Islands,
as well as Bermuda, are situated in the neutral zone to northward, and have
neither breeding noddies nor other terns of tropical affinities.
Belcher and Smooker (1935, 296) state that the Brown Noddies breed at
Soldado Rock, near Trinidad, in April and on rocky islets off the leeward coast
1154 OCEANIC BIRDS OF SOUTH AMERICA
of Tobago during the same month. Like the Sooty Tern, the noddies are said
to have a second nesting season at these localities in July.
At Los Hermanos and other islets on the leeward side of the Antilles, the
Brown Noddies begin to breed about the first of February (Cory, 1909, 226).
To northward and windward they return later in the spring from their migra-
tions, and are at their nesting grounds off Porto Rico, Jamaica, and at the Dry
Tortugas, by early April. The farther northward the breeding station, the more
closely the calendar dates of successive years seem to coincide with the same
stages in the reproductive process. Nesting habits vary considerably, the site
in which the eggs are laid including limestone ledges, bare, shelving surfaces
of rock or sand, or the flat tops of bushes and shrubs such as grow on wind-
swept, semi-arid islands. Likewise, the nature and quantity of nesting material
is highly various, sometimes being only a few pebbles, and again comprising
large quantities of twigs, stranded gulf weed, etc. Thus Bonhote (1903, 315)
writes that in the Bahamas, where incubation begins early in May, the eggs
are deposited indiscriminately upon naked rock, beneath bushes, or in nests
built on top of the vegetation.
Burmeister (1856, 453) long ago reported that the noddies voluntarily
neither dive nor swim. This was again emphasized in Watson's (1908, 187)
classic study, from which many of the following life-history data are drawn.
Yet subsequently, Watson (1910, 470) showed experimentally that the noddies
can swim well, and that they are capable of floating for many hours on the
surface of the ocean without becoming water-soaked, an accomplishment quite
beyond the ability of the Sooty Tern. Ordinarily the feathers of the noddies
touch the water only when they bathe, a feat accomplished by striking against
it without complete immersion. They feed, as do the Sooty and Fairy Terns,
by picking small fry from the surface as they poise on beating wings just above
it. In their usual foraging, Watson found that the maximum distance from the
nesting island to which they go is not more than about 24 kilometers. Beck's
notebook, however, indicates that he has seen them feeding regularly as far
as 50 kilometers from their homes, while the Sooty Terns, according to his
observations, go as far as 300 kilometers. The noddies make free use of every
stake, buoy, bit of flotsam, or any other available resting place over the water;
they will even perch at times upon the head of a swimming pelican. Further-
more, they will sit for long periods on barely exposed reefs and ledges, perhaps
waiting for shoals of fish to appear, perhaps merely preening themselves or
dozing in the bright sunlight. They enjoy light, and react strongly to it; on
brilliant moonlit nights they are likely to be especially active. As noted above,
they seem to avoid swimming, especially during the season of reproduction.
Beck, however, saw flocks resting on the calm water off Bahia, and Meliss
(1875, 98) reports that on rare occasions he has seen small groups afloat in the
roadstead of Jamestown, St. Helena.
Watson's famous experiments show that the noddies display an amazing
ability to regain their nesting sites after being transported varying distances
away. One of two marked birds released east of Cape Hatteras on June 16
BROWN NODDY 1155
reached its nest on Bird Key of the Dry Tortugas five days later, the distance
covered, by direct shore line, being 1739 kilometers. On May 18, 1910, Watson
staged an interspecific race between twelve noddies, twelve Sooty Terns and
four Caribbean Man-o’-war Birds. These he transported from the Tortugas
colony to the harbor of Key West, which is 105 kilometers to eastward. All
the noddies returned to their respective nests after intervals varying between
17% hours and 63 hours, while ten of the Sooty Terns returned at the expiration
of from 1714 hours to 11 days. Watson believed that the longer apparent time
required by the Sooty Terns was due to the fact that their nesting neighbors
objected to the approach of the marked birds to their nests. Two of the four
man-o’-war birds likewise returned, but the period required is not recorded.
Again, three noddies and four Sooty Terns were released in the Gulf of Mexico
at 4.45 a.m. of June 3, after being weakened somewhat by five days of captivity.
Two of the three noddies returned to their nests against heavy winds at the
end of three days, the distance covered being about 740 kilometers in a straight
line, without visual landmarks of any sort. The physiological mechanism of
such homing ability is not yet understood. Winds, ocean temperatures in
relation to food supply, and many other external influences have been suggested
in this connection, when visual stimuli seemed totally inadequate, but we are
still obliged to speak chiefly in terms which do not explain. Strong (1911,
619) has inferred that large olfactory lobes, such as those of the fulmar, may
serve birds as an organ of orientation. The noddies, however, as well as other
species which have shown a highly developed ability to find their way at sea,
have relatively small olfactory lobes and associated nerves. At any rate, it is
the means, rather than the seat, of the ability which is important.
According to Watson, the noddies arrive at Bird Key of the Dry Tortugas
each year during the last week in April, remaining until about the first week in
September. It seems likely that courtship and pairing begin before they reach
their island, and since they copulate only upon land, it is almost certain that
this function is not fulfilled until immediately after arrival. The nodding
reaction between birds is closely associated with mating, although it also
expresses itself in later relationships. Owing to the latitude, and to the surface
of coral sand of Dry Tortugas, the air temperature at ground level during the
hottest summer days reaches maxima as high as 61° C. Vegetation is generally
scanty, but bay-cedar and cactus are both used by the noddies as nest supports.
The nests seem invariably to be placed upon a foundation of stems or grass-
clumps, even though subsequently they may press the under-structure quite to
the ground. The nest materials consist of branches of bay-cedar, dry seaweed,
bits of shell, coral, etc. When shells are used, they are often worked into the
inner lining. The nests are loose and shallow, and since they are used year
after year, many of them grow to a huge size. In building them, the birds
work neither steadily nor rapidly. They steal nest material when they can,
looting unguarded nests so that frequent territorial battles result. Watson
states that the nest-building instinct is one of the least transitory of the birds’
reactions, for they cannot resist the impulse to gather twigs even when they
1156 OCEANIC BIRDS OF SOUTH AMERICA
have young. If a handful of sticks is tossed into the air, all the noddies in the
neighborhood will be after them at once. Nest-building is shared in common
by the sexes, but subsequently the female guards the nest while the male pro-
cures the food for both. The female usually sits close by, inattentive to the
advances of other males that flit about, awaiting the return of her own mate
with food. When he finally alights at the nest, the female at once approaches
and the nodding performance begins. In this reciprocal behavior, the two birds
face each other and one bows its head, quickly raises it almost to a vertical
position, and then lowers it again. This action is repeated over and over, with
great rapidity, and the second bird responds with a similar pantomime. When
the performance is connected with mating, the male begins the nodding and
the female attempts to extract the fish which he is disgorging by a rhythmic
contraction of the throat and body that makes him almost seem as though he
were choking to death. The female, while taking food from his mouth, emits
a soft nasal purr, a sound to be heard on no other occasion. The feeding is
alternated with further nodding, after which the male may fly off and bring a
twig. Feeding is best observed toward sunset, when many males are returning
from sea. Afterwards, the birds nestle together and nod vigorously, copulation
often taking place at this time.
During the nest-building and egg-laying periods the noddies, like so many
other birds, are wild, flying both by day and night from intruders. The single
egg may be laid as soon as there is sufficient support for it, or not until several
weeks after completion of the nest. If an egg is removed from the nest shortly
after it appears, the parent birds will apparently produce another, and will
continue this repetitive process for a considerable period. At Dry Tortugas
Watson found the first eggs on May 4, and by May 25 there were no empty
nests. The majority of eggs were laid during the five days between the 11th
and 16th of the month. Soon after the egg appears, the parental behavior alters
and both mates become active in defense against their own species or other
dangers, the tactual and visual impulses aroused by the egg being responsible
for this change. Moreover, the male now no longer feeds the female, but each
bird takes its turn at brooding and at feeding. The mated birds also give up
their close association, and spend almost no time together except at night. At
the time of relief, the two may remain on the nest for several minutes, nodding
toward each other until the bird about to feed leaves of its own accord or is
pushed off by the new arrival. Experiments show that birds may remain on
the nest as long as 48 hours if the mate is prevented from returning, but that
after about this length of time the sitter will leave its egg unguarded and go
in search of food. Incubating noddies occasionally make very brief trips from
the nest to wet their breast feathers in the ocean.
The period of incubation is from 32 to 35 days. After the young have hatched
the noddies become more pugnacious than ever, and will even attack the frigate-
birds by sudden thrusts from beneath. Both parents feed the young at intervals
of from two to four hours, the chick being cared for in the nest for about two
months or until it is strong enough to flutter to the ground, where it remains
BROWN NODDY 1157
permanently. Thereafter, the returning parents first alight upon or close to
the nest, from where they hop to the ground and feed their chick. Recognition,
so far as one can tell, is wholly in terms of vision.
The egg of the noddy is dull and granular, characteristics which distinguish
it from the egg of the Sooty Tern, the shell of which is smooth or almost
polished. The yolk of the noddy’s egg is, furthermore, of a pale yellow color,
in marked contrast with the bright orange yolk of the Sooty’s egg. Watson
found that the noddies did not reject artificially colored eggs placed in their
nests, although they always appeared more or less disturbed when their mates
had been daubed with bright, abnormal hues. He learned, too, that by putting
an egg in the nest of a pair that had not yet produced its own, he could upset
the ordinary sequence of reactions and change the behavior of the birds from
the wary mood of a layer to the fearless and pertinacious mood of a sitter. It
is certain that the noddy does not recognize its own egg. Neither does it recog-
nize its nest as such, but the position is so exactly localized that, if the nest be
moved even one meter, the returning birds will go first to the old position,
fluttering back and forth for some time before conditioning themselves to the
new one.
The majority of the downy young noddies at the Dry Tortugas are plain
dull black in color, but a few of them have white blotches on the back and
wings, and somewhat less than one per cent of them.are more or less pure white
(Thompson, 1903, 77). Watson found that if white and black chicks are ex-
changed, no disturbance is shown by the deluded parents, even though the age
difference of the respective young may amount to three or four days.
Young noddies can be tamed only if they are reared by hand from the very
first day of their lives. Under such circumstances they normally develop no
fear, but otherwisé they continue to be thrown into a state of absolute panic
whenever a man approaches them.
About the first of September the noddies begin to leave the Tortugas colonies
in great flocks, to depart, apparently, southward. The entire exodus consumes
only two or three days, after which an observer will be able to find only a few
cripples left behind.
Aside from the soft, throaty sounds of courtship behavior, the noddies, in
the aggregate, make a clamor that reminded Nicoll (1904, 36) of rooks during
the breeding season, and Bowdish (1902, 358) of the outcry of young crows.
Wetmore (1918, 338) writes that the members of a colony at Desecheo Island,
Porto Rico, which were as active by night as by day, uttered a loud harsh
guttural kar-r-rk and a scolding note resembling kwok-kwok.
The noddies drink frequently by skimming the surface of the ocean with
open beak. They appear to feed largely by following schools of small fish
which are being attacked by larger fish, picking off the former as they skim
along or skip above the surface, the birds first hovering over the water then
darting downward and poising, at least momentarily, while they snatch the
prey. They gather, of course, in groups at centers of feeding, and then disband
and scatter when the minnows cease to jump. Ordinarily they leave their island
1158 OCEANIC BIRDS OF SOUTH AMERICA
at the beginning of daylight and continue to fly about until the jumping schools
meet their eye. After two hours or thereabouts the fishing noddies return to
relieve their mates at the nests, whereupon the latter take roughly a two-hour
fishing trip, a régime which is substantially followed during the whole season
of incubation and the rearing of the young. Bowdish reports that he found in
one noddy stomach the entire body of a flying fish about 10 centimeters in
length. Watson learned that a healthy chick in captivity will eat from 12 to
40 minnows a day.
SOCORRO NODDY
Anois stolidus ridgwayt
Anoiis stolidus ridgwayi Anthony, 1898, Auk, p. 36 (Socorro Island, Revilla Gigedo group).
Names: A synonym which has been used as a specific name of this noddy is péleatus.
Characters: Similar to the typical subspecies but of slightly darker coloration, the pileum
darker gray, becoming white only on the anterior margins.
9 males: wing, 261.5-292 (272.6); tail, 142-169 (160.5); exposed culmen, 41-43.5 (41.9);
tarsus, 23-26 (24.6); middle toe [without claw], 30-34 G1.3) mm.
18 females: wing, 265-283 (272.6); tail, 141.5-162 (151.1); exposed culmen, 38-43 (40.8); tar-
sus, 23-26 (24.2); middle toe [without claw], 29-32 (30.8) mm. (Ridgway, 1919, 550).
Distribution: Breeds on islands off the west coast of Mexico and Central America, from the
Tres Marias Islands southward to Cocos Island.
The Brown Noddies of the eastern Pacific are generally held to represent
two subspecies, of which the present one is alleged to have a relatively extensive
range, namely from Cocos Island northward to the mouth of the Gulf of Cali-
fornia, while the second is confined to the Galapagos Islands. Regarding the
general life history of these two forms, there seems to be little to add to what
has been reported of the Atlantic race.
The greater part of the range of the Socorro Noddy is in the northern hemi-
sphere, and outside our field. On one of Beck's earlier expeditions he found
large numbers nesting among Sooty Terns on small islets in a lagoon of Clipper-
ton Island. During November, 1898, Snodgrass and Heller (1902, 508) found
these terns very abundant on the high rock at the eastern side of Clipperton
Island: They obtained an egg, showing that the breeding régime in this part
of the Pacific is quite different from that of Brown Noddies at an only slightly
higher latitude in the West Indies. McLellan (1926, 284) reports, however,
that the birds were breeding at the Revilla Gigedo Islands during April and
May, when eggs and also young in various stages were collected. Gifford
(1913, 25) found eggs at the Revilla Gigedos at the very end of July, which
further indicates a prolonged breeding period of the non-seasonal type, such as
we have already encountered in equatorial parts of the Atlantic.
According to Gifford’s experience, noddies were not common on the long
reaches between the various Pacific islands; they were recorded for the most part
within sight of their respective headquarters. During a thirteen-day stay at
Cocos Island in September, he found the nesting colonies on small neighboring
islets occupied by large numbers of young birds which were, for the most part,
nearly ready to fly. The collections studied by Gifford also show that the well-
SOCORRO NODDY 1159
known dichromatism of the downy young pertains to this Pacific race, as well
as to birds of the Atlantic. The dimensions of adult birds, and the pattern,
color, and measurements of eggs, show no appreciable differences from the
respective characteristics of the typical subspecies.
GALAPAGOS NODDY
Anois stolidus galapagensis
Anois galapagensis Sta 1879, Philos. Trans. Roy. Soc. London, 168, p. 469 (Dalrymple Rock, Chatham
Island, Galapagos Archipelago).
Characters: Similar to Anois stolidus ridgwayi but averaging slightly smaller and much darker
and less brownish, the head and neck almost slate color, the forehead mouse-gray, often but little
lighter or grayer than the occiput, though usually with a more or less distinct supra-loral line of
pale gray or hoary gray (Ridgway, 1919, 551).
2 males and 3 females from the Galapagos: wing, 267-284 (273.2); tail, 140-144.2 (141.8);
exposed culmen, 39.2-42 (40.5); tarsus, 22.1-25.5 (24.1); middle toe and claw, 35.5-37.3 (36.6) mm.
These figures substantially agree with those given by Ridgway (1919, 551) for a larger series.
Gifford (1913, 29) states that Galapagos specimens average somewhat smaller than those from
Cocos and Clipperton with which he compared them. He also records the length in the flesh of
four Galapagos males as measuring 396-440 mm. and the wing-expanse from 824-855 mm. The
corresponding ranges in six females were, length 380-400 mm.; wing-expanse, 784-821 mm.
Eggs appear to be indistinguishable in size and pattern from those of other Brown Noddies.
Distribution: The Galapagos Archipelago; recorded from upwards of twenty islands or islets
within the group.
According to Snodgrass and Heller (1904, 329), this Brown Noddy is abun-
dant throughout the Galapagos Archipelago. At Tagus Cove, Albemarle
Island, the birds were found nesting in cavities of the high. bluffs of tufa facing
the ocean. Here they began to mate after the middle of January, and on February
1 eggs were found. Some of the sites were so close to the water that they could
be reached from a boat. The nest in all cases was scanty, consisting merely of
a few twigs in the bottom of the cavity. That the breeding period is not
seasonally rhythmic at the Galapagos Archipelago as a whole is indicated by
the fact that Snodgrass and Heller again found noddies nesting at James Island
during April. Gifford (1913, 25) later records the months of January, February,
March, April, July, and September as periods during which eggs have been
found at one island or another. For the same reason his detailed notes on moult
reveal little or no seasonal correlation.
Gifford confirms the general nesting habits as recorded above, and states
that the birds occupy ledges and crevices, usually not more than 10 meters
above the water, and that bones, seaweed, remains of crabs, and feathers enter
into the composition of the nests.
Gifford also reports that the Galapagos Noddies accompany Brown Pelicans
on their fishing excursions, and that he once saw two noddies perched on the
head of a floating pelican which was in the act of swallowing fish. He observed
foraging noddies to a distance of about 100 kilometers from the shores of the
islands.
The last information brings us to consideration of the very rare pelagic
1160 OCEANIC BIRDS OF SOUTH AMERICA
records of Brown Noddies in the eastern South Pacific. As previously noted,
these birds appear to be barred permanently from the littoral waters south of
the equator by the unfavorable hydrographic conditions of the Humboldt
Current. However, Scouler (1826, 210) reports that early in January, on the
course between Juan Fernandez and the Galapagos, a number of noddies perched
in the rigging of his ship several days’ sail to southward of the archipelago,
and allowed themselves to be caught in the hand. Paessler (1913, 45) captured
a female in latitude 7° N., longitude 84° 8’ W., on July 8. The position is mid-
way between Cocos Island and Panama, and the bird is likely to have been a
member of the Socorro race rather than that of the Galapagos.
SAN FELIX NODDY
Anois stolidus, subspecies
1 male: wing, 294; tail, 161.2; exposed culmen, 41.6; tarsus, 25.2; middle toe and claw, 39.4 mm.
2 females: wing, 281, 285; tail, 155.5, 155.7; exposed culmen, 39.8, 41.6; tarsus, 24.3, 25;
middle toe and claw, 36.5, 36.9 mm.
The discovery of Brown Noddies in residence at San Felix Island adds to the
interest of the pelagic records cited in the preceding biography. Scouler’s
observation, for example, may well refer to birds from this source.
During the visit of the ‘Zaca’ on February 18, 1935, Dr. Chapin collected a
male and two females at San Felix. All three were non-breeding adults under-
going a moult of the quills. The stomachs of two contained remains of small fish.
The wings and tails of these few birds average longer than those of the races
inhapiting more northerly parts of the eastern Pacific. Their exact taxonomic
satus can be determined only by comparison with noddies from other parts of
the South Pacific, of which adequate but still unstudied series have been ob-
tained during the long campaign of the Whitney South Sea Expedition. By
way of preliminary record, however, I give above the measurements of the San
Felix specimens.
ATLANTIC BLACK NODDY
Anotis minutus atlanticus
Megalopterus minutus atlanticus Mathews, 1912, Birds Australia, 2, p. 423 (Ascension Island).
Names: Atlantic, or Caribbean White-capped Noddy; Tree Noddy; Lesser Noddy; Piccary
Noddy in British Honduras: ‘‘Mauve Noire’’ in the French West Indies. Synonyms of the
specific name are fenutrostris, melanogenys, and leucocapillus.
Characters: Differs from the greater noddies in its blackish rather than brownish coloration,
in having a whitish pileum and nape, and in its smaller size.
Adults (sexes alike): General color plain deep sooty brown, blackish brown, blackish fuscous
or sooty black, passing, through a lighter and grayer hue on hind neck, and neutral gray on nape,
into immaculate white or grayish white on pileum; lores and space immediately above eyes black
(in strong and abrupt contrast with white of forehead and crown), the lower eyelid with a white
streak; tail and longer tail coverts (both upper and lower) brownish gray (between mouse-gray
and deep Quaker drab); bill black; iris dark brown; legs and feet dusky brownish (Ridgway,
1919, 554).
9 males from Fernando Noronha, Ascension and St. Helena: wing, 225-240 (231.1); tail,
ATLANTIC: BLACK NODDY 1161
109.6-120 (116.3); exposed culmen, 42.5-48.1 (46); tarsus, 22-23.3 (22.5); middle toe and claw,
31.1-36 G34) mm.
3 females from Fernando Noronha: wing, 228-230 (229); tail, 111.2-117.1 (114.2); exposed
culmen, 42.1-44.8 (43.2); tarsus, 21.6; middle toe and claw, 34.3 mm.
Lengths in the flesh of 12 examples of both sexes from Ascension, St. Helena, and Fernando
Noronha ranged between 349 and 384 mm.; wing-spreads among the same birds between 663
and 714 mm.
Immature: Forehead and crown white; lores white; neck and nape sooty black, which throws
the white crown into strong relief, owing to the absence of any intermediate lead color; mantle,
tail, and under parts umber-brown, the primaries blackish.
Young: Forehead and anterior crown white; lores black; upper parts generally umber-brown,
with cinnamon borders to the wing coverts and secondaries; primaries blackish; under parts mouse-
brown. In an older bird the white is less pure, but extends farther back on the crown, and the
plumage has a slightly barred appearance.
Downy young: Forehead and crown dull white, rest of the body sooty black (Ridgway,
1919, 554).
I find no satisfactory description and measurements of the eggs of South Atlantic birds. Oates
(1901, 199) states that eggs of this species (but of one or more different subspecies) from the Pacific
are broadly oval or elliptical, with a ground color varying from nearly pure white through cream
to pale pink. The surface markings, which range in size from specks to huge blotches, are of a
deep reddish brown or chocolate-brown intermingled with lines and comma-like dashes. The mark-
ings are chiefly confined to the larger end; feebly marked or nearly plain eggs are not uncommon.
Examples measure in length from 41.9-49.5 and in breadth from 30.5-33.5 mm.
Distribution: Islands in the tropical and sub-tropical South Atlantic Ocean from St. Paul
Rocks and Fernando Noronha to Martin Vas, St. Helena, and Tristan da Cunha, the last being
at the edge of the Sub-Antarctic Zone. (A form of this species recognized by Peters (1934, 348)
also breeds on islands off the coast of British Honduras, at the western extremity of the Caribbean
Sea. Its flight-range may bring it within the South American area, but as to this I have no data.)
In the Atlantic Ocean and its connecting gulfs the White-capped Noddy has
a range similar to that of its larger brown cousin, though somewhat less exten-
sive. While it appears in several ways to be more adaptable than the Brown
Noddy, particularly as regards the varied nature of its nesting sites, it requires
at the same time certain special conditions. These include opportunity to
obtain an abundance of seaweed or other fresh, green, and damp material, and
also an area, not on flat ground, in which it can construct a bulky nest, prefer-
ably in a sheltered and shaded situation. Thus, while it takes freely either to
trees or to the walls of cliffs and caverns, it appears to be instinctively condi-
tioned against laying its single egg upon a bare ledge of rock, or a surface of
pebbles or sand, such as the Brown Noddy tolerates without difficulty when
terrestrial vegetation is wanting.
The Black Noddy inhabits most of the tropical and sub-tropical Atlantic
islands between latitudes 1° N. and 37° S. As might be expected, it is not found
at the low, flat, and practically treeless and shrubless atoll of Rocas Reef. Its
apparent absence as a breeding bird from South Trinidad is more puzzling,
especially since it is a regular member of the avifauna at the near-by Martin Vas
Rocks, where it was first reported by Nicoll (1906, 673) on January 5, 1906.
When I visited Fernando Noronha in October, 1912, this species seemed to
be by far the most abundant bird. Six examples were collected, all of them in
a breeding state. The ‘Blossom’ expedition subsequently found the Black
1162 OCEANIC BIRDS OF SOUTH AMERICA
Noddies nesting at several islets of Fernando Noronha in March, and earlier
visitors had made note of reproductive activities during other months.
The nesting habits of the Black Noddy appear to have been most fully
observed at the barren St. Paul Rocks, where the species is known from abundant
evidence to breed throughout the year. As noted in the biography of the
Atlantic Brown Noddy, the explorers of the ‘Beagle’ and the ‘Terror,’ as well
as certain other visitors, have confused these two related terns. At St. Paul
Rocks and other plantless islands, however, the Black Noddy always builds a
nest of the only available material, which is green seaweed torn from the rocks
by the surf and gathered up by the birds as it floats. Furthermore, the nest is
built upon a small rocky projection of a sheer wall or a steep slope, the whole
forming a bracket of sopping vegetable matter plastered over with, and more
or less cemented together by, the birds’ dung. Such nests grow to be 15 to 20
centimeters in height. They appear to be used continuously for, as Wilkins
has pointed out, the structure shows no definite horizontal lamination such as
would appear if it were added to and occupied only at one definite season each
year. Doubtless a new breeding pair of terns is ready to take possession as
rapidly as a preceding couple and grown chick relinquish the site.
The Black Noddy nests of St.Paul Rocks have been well described by Moseley
(1879, 69) and McCormick (1884, 20), and the former has published a drawing
in his narrative of the ‘Challenger’ voyage. The top of each nest is a sort of
platform, or very nearly a plane surface, instead of being hollow.
Similar bracket-nests were seen against the wall of a gloomy cleft in the
Martin Vas Islands during the visit of the Cleveland Museum party. Also one
Black Noddy was collected here, but the specimen was subsequently lost.
Structures of the same sort were noted by Moseley (1879, 563) against the lower
part of the cliffs of Boatswain-bird Islet, Ascension, at the end of March, and
Penrose (1879, 280) states that these same cliffs were black with the adult birds
on January 4, 1878, at which time each pair had one egg resembling that of the
Brown Noddy but smaller and more pointed. Nesting Black Noddies were
also collected at Boatswain-bird Islet by the ‘Blossom’ expedition between
September and November, and at St. Helena in September.
At the islands of Tristan da Cunha this noddy is a migratory species, which
has been observed or captured at all three members of the group between Septem-
ber and February. While perhaps not distinguished by the Tristan folk from
the Brown Noddy, it is certainly the black species which, because of its tree-
nesting proclivities, deserves the name of *‘Wood Pigeon."’ Carmichael (1818,
497) reported that these birds nested abundantly in the buckthorn (Phylica)
trees early during the nineteenth century, when woods still existed at Tristan.
More recently the noddies have been found in the groves of Inaccessible Island,
building nests of sticks and leaves (Thomson, 1878, 156), or loitering about
the large sea caverns of Nightingale Island.
Both at the borders of the sub-antarctic realm, and in the northeast trade-
wind zone of the northern hemisphere, the Black Noddies share a fixed or
calendar breeding period which, however, they have lost in greater or less
ATLANTIC BLACK NODDY 1163
degree throughout the pan-tropical oceans. Thus at a cay off Belize, British
Honduras, Black Noddies (either of the present subspecies or one very closely
related to it) nest regularly during the northern spring, though slightly later
in the season than the Brown Noddies of the same locality. The nests, of
slender twigs and bits of seaweed, are built mostly in the mangroves (Salvin,
1864, 383). No doubt with the destruction of trees at such sub-tropical islands
as St. Helena and South Trinidad, the status of the Black Noddy has changed
enormously. It is perhaps for such reasons, indeed, that the bird appears no
longer to reside at South Trinidad.
The Black Noddy feeds like the other species, not by diving but by making
quick stoops to the surface of the ocean and seizing unsuspecting fish as they
rise or leap out. Apparently it forages by night fully as much as by day.
Salvin states that this species has a more tern-like call than the cawing note
of the Common or Brown Noddy.
COCOS BLACK NODDY
Anotis minutus diamesus
Micranous diamesus Heller and Snodgrass, Condor, 3, p. 76 (Cocos Island).
Characters: Similar to the preceding subspecies but differing in having a shorter and more
slender bill, and in being darker on the shoulders, lower parts, and the sides of the head and neck.
2 males from Cocos and Clipperton Islands: wing, 232-239 (235.5); tail, 122.8-125 (123.9);
exposed culmen, 45-45.6 (45.3); tarsus, 21-22.1 (21.5); middle toe and claw, 34.5-35.5 (35) mm.
2 females from Cocos and Clipperton Islands: wing, 224-225 (224.5); tail, 111.5-113.3 (112.4);
exposed culmen, 37-41.7 (39.3); tarsus, 20.3-20.4; middle toe and claw, 33.7-34.4 (G4) mm.
Heller and Snodgrass (1902, 510) give the following average measurements for 9 birds of both
sexes, chiefly females, from Cocos and Clipperton: length in the flesh, 369; wing, 230; tail, 128;
exposed culmen, 43.6; depth of bill at base, 8.4; tarsus, 21 mm.
Gifford describes eggs from Clipperton Island as of elliptical-ovate or elongate-ovate form, and
in color and markings resembling those of the Brown Noddy. Examples measure 43.7 x 32,
46 x 30.8, and 44.8 x 31.5 mm.
Distfibution: The Pacific coast of Central and northern South America, breeding at Cocos
and Clipperton Islands. ‘
The distinction between the Atlantic and the eastern Pacific Black Noddies
is, perhaps, unduly emphasized above; it may be less marked than was believed
by the original describers of the subspecies diamesus, and by subsequent re-
viewers. Certainly the alleged difference in the length of the bill seems to be
scarcely perceptible. The comparison of measurements made by Ridgway (1919,
555 and 557) is of no aid, because his figures intended to represent dimensions
of diamesus are based upon examples of the small noddies of the British Honduras
coast, which have since been recognized as still another subspecies, called
americanus. As 1 have examined only four specimens of the Cocos Black Noddy,
I am unable to settle the taxonomic status of the bird to my own satisfaction.
Heller and Snodgrass state that the Cocos Black Noddy is intermediate
between Atlantic birds and the form occurring at the Hawaiian Islands. They
found this tern abundant in July, at Cocos Island, where it was nesting inland
in tall trees, closely associated with the white Fairy Tern. Gifford (1913, 30)
1164 OCEANIC BIRDS OF SOUTH AMERICA
encountered the Black Noddy at sea, about 50 kilometers south of Cocos Island,
on September 1, 1905, a date when young birds on the wing appeared to be
more numerous than adults.
At Clipperton Island, during August, Gifford found these noddies nesting
on little juttings of rock from the walls of cliffs and caves, building their nests
of soaking wet algae from the lagoon, and obviously using old nests as a foun-
dation. The birds showed no timidity, and numbers were caught by hand.
Tue Farry Terns, Genus Gycis
These white terns are birds of tropical and sub-tropical oceans, inhabiting
remote islands rather than those near continental coasts. They appear to be
most abundant just outside the zone of tropical surface water, either close to
the borders of pronounced current movements, or where the submarine slopes
of small oceanic islands tend to cause a concentration of life at the surface.
Two subspecies come within the South American region. The Atlantic birds
constitute the typical race. The affinities of the Cocos Island form are with
birds occupying other parts of the Pacific, but its exact status has not yet been
settled.
ATLANTIC FAIRY TERN
Gygis alba alba
Sterna alba Sparrman, 1786, Mus. Carls., fasc. 1, no. 11 (East Indies, Cape of Good Hope, and islands of
the Pacific Ocean = Ascension Island, South Atlantic).
Names: White Noddy; Snow-white Tern; Love Bird; Holy Ghost Bird. Spanish names include
“Paloma de Mar"’ and ‘‘Quia-quia.’’ The commonest synonym of the specific name is candida; the
Atlantic form has also been described as crawfordi.
Characters: Birds of this genus are the only terns with pure white plumage.
Adults (sexes alike): Plumage white, except for a narrow ring of black feathers around the
eyelids; shafts of primaries and rectrices sometimes dusky or brownish even in apparently mature
birds. Iris brown; bill black; legs and toes slaty blue, the webs white or yellowish.
8 males from Fernando Noronha, Ascension, South Trinidad, and St. Helena: wing, 239-250
(249.1); tail, 92-105.5 (98.6); exposed culmen, 39.2-43.8 (41.7); tarsus, 13.5-15 (14.2); middle
toe and claw, 25.5-28.8 (27.5) mm.
8 females from the same localities: wing, 240-268 (250.1); tail, 90-115 (102.8); exposed cul-
men, 38.6-41.5 (40); tarsus, 13.2-15.4 (14.1); middle toe and claw, 27-29 (27.9) mm.
The total wing-spread of 18 specimens of both sexes from the South Atlantic islands ranged
between 698.5 and 870 mm., the average being 739 mm.
Immature birds have a post-ocular blackish spot and dark quill shafts, while the feathers of
the nape and back, as well as some of the quills, are tipped with rusty brown. The downy nestling
is grayish brown with two broad blackish stripes on the back and a black patch on the crown;
the short bill is plumbeous, the feet relatively very large, and the stout toes strongly clawed.
Eggs are described as more uniformly elliptical in shape than those of most terns, being de-
cidedly blunt at both ends. The ground color is usually creamy, though varying between dull white
and pale buff. The markings, of widely varying shades of brown, consist of scrolls, lines, specks
and blotches spread thickly over the surface and forming a very handsome pattern. Underlying
markings beneath the surface of the shell appear as pale purple. I find no measurements of South
Atlantic eggs. Three from the Kermadec Islands, in the South Pacific, measure: 44.5 x 32.5,
42.5 x 34, and 41.5 x 30.5 mm.
Distribution: Breeds at Fernando Noronha, South Trinidad, Martin Vas Rocks, Ascension
and St. Helena, South Atlantic Ocean.
ATLANTIC FATRY TERN 1165
Most ethereal of sea birds are the delicate and gentle Fairy Terns. Their
plumage is white, but with subtle ivory or creamy tones and with a barely
perceptible reddish gleam visible in certain lights on the feathers of the belly.
The last is all but illusory, and yet I find that most persons can see it if they are
asked whether the ventral surfaces of specimens show a bloom of any sort. In
the air these terns are ghostly creatures, their exceptionally large black-rimmed
eyes sometimes seeming like empty sockets. Moreover, when they fly overhead
against the brilliant tropical sky, only the bones and flesh of their filmy wings
fully obstruct the light. At such times the Fairy Terns resemble tiny flying
skeletons, except that their lightness and grace are more suggestive of dis-
embodied spirits than of dry bones. It is curious that under their rather thin
and loose white plumage they have a skin which is black and shiny, like that
of a newly hatched naked cormorant. No doubt the dermal melanin of the
Fairy Tern bears the same relation to the absorption of the sun’s rays, or to the
retention of bodily heat, as does the dark plumage pigment of its neighbor, the
noddy, which has a white skin.
My first experience with the Fairy Terns came on October 16, 1912, when I
landed from the brig ‘Daisy’ for one day at the island of Fernando Noronha.
Here this species proved rare in comparison with many of the other sea birds,
for not more than twenty Fairy Terns were observed, most of them in pairs
flying from shelf to shelf of the cliffs or sitting affectionately side by side across
the boughs of trees. Later during the same voyage, on April 8, 1913, I found
the species to be far more abundant at South Trinidad Island. Here, again, the
terns seemed to associate in devoted family groups of two, whether flying over
the ocean or resting in niches of the rocks. This habit has been noted by other
observers, and Thomson (1878, 109) says that in the flying pairs one bird follows
very closely all the motions of the other. According to Penrose (1879, 279),
who made his observations at Ascension, the breeding pairs seldom flock with
others of their own kind, and they likewise tend to keep apart from the noddies
and larger birds.
The curiosity of the Fairy Terns is notable, and Meliss (1875, 98) states that
they are particularly attracted by white objects. They have a way of fluttering
just in front of one’s face in a manner that soon becomes disagreeable—not
attacking, but merely staring, hovering like overgrown mosquitoes, and wheez-
ing in a way to suggest the buzz of some such noxious insect. McCormick
(1884, 25) tells us that during his solitary ramblings about South Trinidad, on *
the occasion of the visit of the ‘Terror’ in January, 1840, his only constant
companions were the Fairy Terns that never ceased to hover about his head.
As I sat in a whaleboat on the heaving swells close against the cliffs of the same
island, a succession of these birds fluttered just in front of my nose so that I was
able to pick them out of the air by hand. After being captured, they made no
resistance except for a very mild and brief struggle, and they did not attempt
to use their potentially dangerous bills. Although perfectly willing to shoot
specimens at shotgun range, I found that the only thing to do with the big-
eyed creatures that nestled unhurt in my hand was to set them free again.
1166 OCEANIC BIRDS OF SOUTH AMERICA
The typical form of the Fairy Tern is confined to the tropical and sub-tropical
islands of the South Atlantic. In Part I of this book I have noted as curious
the fact that it has never succeeded in jumping the relatively short gap between
Fernando Noronha and the Antilles, which lie at no great distance directly to
leeward. The presence of Fairy Terns at Cocos and Clipperton Islands, in the
tropical Pacific adjacent to the coast of America, might lead to the inference
that Atlantic members of the species had at one time “‘broken through,”’ just
as Atlantic types of man-o’-war birds, pelicans, flamingoes, teals, etc., are known
to have found their way to the Galapagos Archipelago. However, it can safely
be inferred that the Cocos and Clipperton Fairy Terns are not of Atlantic origin,
but that their affinities are rather with the forms of the species found in southern
Polynesia. At any rate, bills which are relatively deep at the base are shared
by representatives from islands in various parts of the tropical Pacific, and are
distinguishable at a glance from the slender bills of all South Atlantic birds.
I judge that the Fairy Terns are quite sedentary at the South Atlantic islands.
Not only have they been reported at all seasons, but Vanh6ffen (1905, 511) states
that when the ‘Gauss’ left St. Helena on September 2, all the terns of this
species remained behind after the vessel had gone about 35 kilometers from the
land. Among the Pacific representatives, however, there are certain records
that suggest a pelagic migration. Thus Oliver (1930, 258) quotes Bell to the
effect that White Terns begin to return to the Kermadecs usually about the
first week in September, although they are rather irregular from year to year
both as to the time of arrival and the date of laying. They come from sea, the
observer continues, generally in small groups, and settle at once in the trees
in which they later breed. There may be much still to learn about a migratory
movement in the South Atlantic. It must be kept in mind, however, that the
surface waters about their South Atlantic breeding grounds are relatively poor
in food organisms, except in the shore waters of the very islands which are the
strongholds of these terns. Moreau (1931, 779) reports a sight identification of
a group of Fairy Terns “‘about 250 miles north of Ascension’’ on September
30, 1930.
As near as one can judge from the record, the Fairy Tern at Ascension, which
is regarded as the type locality of the species, is not particularly abundant and
is best known as a nester on Boatswain-bird Islet, where specimens now in the
American Museum Collection were obtained in 1925 during the cruise of the
- Cleveland Museum schooner ‘Blossom.’ St. Helena and South Trinidad, both
of which are sub-tropical rather than tropical, have much larger populations
of Fairy Terns. Meliss (1875, 98) reports that at the date of publication of his
book the species was certainly one of the most abundant of sea birds at St.
Helena, its numbers coming next, perhaps, to those of the noddy. He states
that they are often seen flying over the high central part of the island, and that
they nest on rocky cliffs or in irregularities in the surface of the standing basaltic
dykes, such as the column known as Lot’s Wife. Because of such breeding
habits, they may be found in apparently intimate association with the tropic-
birds. Moreau adds that in 1930 he saw Fairy Terns nesting on the cliffs that
ALLAN TiC’ PFATRY | TERN 1167
overhang the quay at Jamestown, and one covering an egg above a church door
in the main street of the town.
At South Trinidad the Fairy Terns nest not only in rocky situations, but also
on the limbs and trunks of the dead Brazilwood forest. A slight hollow or
roughened spot, or a level knot from which a branch has long since fallen away,
are all that the birds need as a ‘‘nest’’ for their single egg. Wilson (1904, 211)
reports eggs and young in various stages of growth at South Trinidad on Sep-
tember 13. Nicoll (1908, 45) also found young not long out of the egg in Janu-
ary. From these and other scattered data it appears that the Fairy Tern may
have here a year-long reproductive season, like so many other pan-tropical
sea fowl.
From all of the above, it appears that the Fairy Tern is equally at home on
stark rocky islands, among forests of trees dead or alive, or in jungles and
thickets of shrubbery. Its primitive nesting preference would seem to call for
the limbs of trees, or the swaying fronds of palms, but where vegetation does not
exist, or has disappeared, the bird takes readily to the rocks and lays its ex-
quisite egg in all sorts of situations, from ledges barely out of reach of the
waves to niches in the walls of mountainous valleys far from the sea. In view
of the change in the flora of such Atlantic islands as South Trinidad, St. Helena,
and Ascension, as described or inferred in the geographic section of this book,
it would seem as if the Fairy Terns must have survived through periods of pro-
found alteration. For such reasons, no doubt, their relative abundance has
also fluctuated greatly within the historic period.
The egg of the Fairy Tern is so precariously balanced on rock or bark, or
even in a slight hollow of a smooth and slender branch, that it has often been
wondered why more of them do not come to grief. Mechanically, however,
the balance of the egg in its cradle is doubtless less insecure than it appears to
be, and the incubating adult seems to stand lightly astride it, rather than
snuggling down upon it in the manner of most birds. The adults cling so fixedly
to their eggs or young that they may commonly be stroked or picked off; they
will even stick to the spot after an egg has been deftly extracted from beneath
them! The chicks are particularly adapted to trapeze tactics. With their very
strong claws, and also with their bills, they cling tightly to their perches, and
are quite capable of hauling themselves back into position after they have been
bowled over by the hurried departure of a parent. Wilson compared their
tenacity with that of limpets! They are extraordinarily precocious, and they
fly about long before they have lost all the down from the tips of their rusty-
tinted white feathers.
Like the Sooty Tern and the noddies, the Fairy Tern feeds not by diving but
by the amazingly rapid and precise technique of catching little fishes in mid-
air as they leap out. Around South Trinidad and other South Atlantic islands
there are many halfbeaks (Hemirhamphus) in the warm surface water, and
doubtless the Fairy Terns capture small examples of these fishes among others,
as they are known to in parts of the Pacific (Fisher, 1906, 785). They are capable
of catching not only one little fish, but even a second and a third, without
1168 OCEANIC BIRDS OF SOUTH AMERICA
dropping the earlier victims from their bills. They then return to the home site,
carrying the prey crosswise, and feed the chick. Small crustaceans have also
been found in their stomachs.
COCOS FAIRY TERN
Gygis alba (candida?)
Sterna candida Gmelin, 1789, Syst. Nat., 1, pt. 2, p. 607 (Christmas Island, Pacific Ocean).
Characters: Bill proximally stouter and deeper than in Atlantic birds, and shading from a
distal black coloration through purple to indigo-blue at the base.
1 male from Cocos Island and 1 female from Clipperton Island: wing, 245-246 (245.5); tail,
108.1-113.5 (110.8); exposed culmen, 40.5-42.3 (41.4); tarsus, 12.8-13 (12.9); middle toe and
claw, 29-30 (29.5) mm. The depth of the bill at the base in the male is 11.5 mm., as against 9.3 mm.
for the same dimension in a male from Ascension. Gifford (1913, 34) gives measurements of 20
specimens, which appear not to differ materially from those of Atlantic birds or of birds from
the central Pacific.
Distribution: Eastern tropical Pacific, including Cocos, Clipperton, and the Revilla Gigedo
Islands; wandering southward to the Galapagos. (The form found in this region may or may not
be that of the central Pacific; at present I see no grounds for separating them.)
Recent reviewers, such as Ridgway (1919, 559), Swarth (1931, 66), and Peters
(1934, 349), are uncertain as to the correct subspecific name applicable to the
form of the White Tern occupying Cocos and Clipperton Islands, and recorded
from as far south as the Galapagos. Ridgway tentatively uses the subspecific
name candida which belongs to birds of the middle tropical Pacific. In this I
follow him, pending a study of the unequalled series of Fairy Terns collected
in the Pacific by the Whitney South Sea Expedition.
Upon the basis of a comparison of one skin from Cocos and one from Clipper-
ton with a large number of Atlantic and Pacific specimens, these terns are at
least divisible according to their respective oceans. In other words, the affinities
of the Cocos and Clipperton birds are with those of more distant Pacific islands
rather than with the South Atlantic subspecies.
Swarth (1934, 221) speculates as to why the White Tern of the eastern tropical
Pacific, which nests abundantly at Cocos Island, occasionally strays southward
as far as the Galapagos and yet fails to establish itself there. He suggests, no
doubt correctly, that the existence of the species is probably dependent upon a
- warm current that sweeps southward a little beyond its breeding outpost. The
only actual Galapagos record seems to be that of Gifford (1913, 32) of a bird
sighted off Tower Island, on September 14, 1906; however, a female was col-
lected ‘‘40 miles south of Cocos.”’
In the same paper Gifford reports upon the resident Fairy Terns of Cocos
Island, as observed during the expedition of the California Academy of Sciences.
Here they were commonest in the forests, which are very luxuriant on this well-
watered island.
It is in this setting that the terns appear to greatest advantage. Asa rule, the first intimation
a person gets of their presence is a startling clucking over his head. Upon looking up he will find
two or three of these beautiful inhabitants of the forest hovering within a yard of his head. After
flying about him four or five times, they will dart away among the trees with a flight as sure as
that of any woodland bird.
COCOS FAIR Y TERN 1169
Over the water their flight was very swift and erratic, and usually at a considerable elevation.
None were seen on the water. They paid but little attention to a boat, seldom approaching to
examine it. At times they were seen in pursuit of each other, and then their evolutions were the
swiftest. One day eight or ten were seen pursuing an Osprey (Gifford, 1913, 33).
The observations of Snodgrass and Heller (1902, 511) regarding the nesting
of this species at Cocos were evidently made in error. They seem to have mis-
taken twig-built structures resembling the nests of crows for the homes of
Fairy Terns, whereas it is certain that the species nowhere constructs a nest of
any sort.
THE SKIMMERS
FAMILY RYNCHOPIDAE
Skimmers are highly modified tern-like birds, found in both continents of
the New World, and in Africa and southern Asia. They all have exceedingly
long wings, correlated with a distinctive style of flight, but their outstanding
morphological characteristic is the compressed, blade-like bill, in which the
lower mandible is much longer than the maxilla. This structure results from
differential growth, for young skimmers have mandibles of equal length, with
the tips of which they are said to be capable of picking up food from the ground.
In many parts of the world, skimmers belong to great rivers more than to
littoral ocean waters. This is true, for example, throughout the eastern drainage
systems of South America, where the birds breed mostly or wholly on river-
bars exposed during the seasons of low water. Perhaps the reason why the
Black Skimmer of southern North America is an almost exclusively coastal
bird is connected with the fact that the flood periods of the larger rivers coincide
with its breeding season.
The American skimmers are black and white birds, all of a common stamp,
though it is possible that they represent two species. The last question can be
solved only when the ranges of several forms in the two fairly well-marked
groups have been determined with a closer approach to exactitude.
BLACK SKIMMER
Rynchops nigra, and its forms
According to the revisional list of Peters (1934, 349), the American skimmers are represented
by four geographic races, but the ranges and status of all of these had not been satisfactorily
determined.
Griscom (1935, 544) has more recently reviewed the group, making use of the excellent South
American series in the British Museum. He prefaces his account with the following general
observations:
“In typical nigra and other ‘white-tailed’ races younger and non-breeding specimens have more
grey in the inner webs of the rectrices than breeding adults; thus younger winter specimens of nigra
cannot be separated from adult breeding zntercedens on this character. Secondly, size steadily in-
creases southwards; roughly speaking, all North and Middle American Skimmers are smaller and
all South American larger. Thirdly, it is by no means definitely proved that the dark-tailed smoky
cinerascens Spix is not really specifically distinct from nigra. Certainly the recently proposed inter-
1170 OCEANIC BIRDS OF SOUTH AMERICA
media Rendahl by no means closes the absolute gap between the two series of races. Here the
taxonomic treatment is largely a matter of opinion rather than fact.”
Disregarding the precise degree of relationship, the five New-World forms of skimmers now
recognized are as follows:
Rynchops nigra nigra
Rynchops nigra Linnaeus, 1758, Syst. Nat., edit. 10, 1, p. 138 (coast of South Carolina).
Breeds on the Atlantic and Gulf coasts of the United States, from Long Island to Florida and
Mexico; winters southward to northern South America, although, according to Griscom, speci-
mens reported from the coast between Trinidad and northeastern Brazil should be critically
redetermined.
Rynchops nigra oblita
Rynchops nigra oblita Griscom, 1935, Ibis, p. 545 (Acapam Lagoon, Pacific coast of Guatemala).
Ranging along the Pacific coast from Guatemala to Tepic.
Rynchops nigra intermedia
Rynchops melanura intermedia Rendahl, 1919, Ark. Zodl., 12, no. 8, p..12 (Harbor Head, Rio San Juan del
Norte, Nicaragua).
Caribbean coast of Central America, off Nicaragua and Yucatan. Also said to be the form of the
Pacific coast of South America, from Ecuador to southern Chile.
Only two Caribbean examples of this subspecies are yet known in collections, and Griscom
suspects that the birds from the Pacific coast of South America will eventually prove to follow the
rule of being of larger size, and will therefore require a new name.
Rynchops nigra cinerascens
Rhynchops cinerascens Spix, 1825, Aves Bras. 2, p. 80, pl. 102 (River Amazon).
Coasts and rivers of northern and northeastern South America, from Colombia (Rio Magda-
lena), Venezuela, the Guianas, and northern Brazil, southward and inland throughout the rivers
of Amazonian drainage.
Rynchops nigra intercedens
Rhynchops intercedens Saunders, 1895, Bull. Brit. Orn. Club, 4, p. 26 (Sao Paulo, Brazil).
Coasts and rivers of eastern and southeastern South America, from Maranhao southward to
the estuary of the Rio de Ja Plata and central Argentina.
Griscom notes that the skimmers break up into a ‘‘nigra’’ group, with a white under-wing,
broadly white-tipped secondaries, and largely white rectrices (in breeding adults); and a “‘cineras-
cens’’ group, with a sooty gray under-wing, very narrowly white-tipped secondaries, and a sooty
tail. It is these two divisions which, he notes, might be regarded as distinct species. The first
would include the races nigra, oblita, and intercedens of the preceding list; the second would comprise
the races cinerascens and intermedia.
I have not seen a sufficient number of specimens of South American skimmers to make an
original or fully adequate discrimination of the forms pertaining to that continent, especially since
the exact ranges of most of them are still somewhat dubious. The following notes are based upon
material in the American Museum and the accounts of Ridgway (1919, 451), Rendahl (1919, 12),
Hellmayr (1932, 403), and Griscom.
R. n. nigra. Characterized by small size, together with the white wing-lining and other fea-
tures noted above. Average dimensions of 10 males: wing, 382; tail, 124; culmen, 68; tarsus, 33;
middle toe without claw, 23 mm.
R. n. intercedens. Larger than the preceding race, the inner webs of the lateral rectrices always
with more brownish gray. Adults in breeding plumage do not, according to Griscom, show the
brownish gray tinge on the wing-lining which is usually credited to this subspecies. Average
dimensions of 6 males: wing, 403; tail, 124; culmen, 79; tarsus, 35; middle toe without claw, 24mm.
R. n. cinerascens. Larger than either of the two preceding members of the “'nigra’’ group. Under-
wing light sooty gray, secondaries much less conspicuously tipped with white, tail deep sooty,
BLACK SKIMMER 1171
the rectrices (except middle pair) very narrowly edged with white externally. Average dimensions
of 3 males: wing, 414; tail, 124; culmen, 87; tarsus, 36; middle toe without claw, 24 mm.
The above three forms are skimmers of Atlantic coasts or Atlantic drainage waters. The only
Pacific form coming within our field is the one at present attributed also to the Caribbean coast of
southern Middle America, namely:
R. n. intermedia. Apparently smaller than cinerascens, its closest relative (fide Griscom), and
approximating intercedens in size. Under-wing smoky gray; rectrices dark umber on the upper
surface, their white outer edges about 2 mm. broad; band formed by whitish tips of secondaries
narrow and rarely pure white. Measurements are as follows:
Wing | Tail |Culmen, Gonys | Tarsus oe
Ciemendahlisity peo (acer naa rear 405.5 | 126 80 110 | 37.5 32.5 mm.
o’, Paracas Bay, Peru, Oct. 19,1919 . . .| 406 125 84.4 33.5 | 26
9, Paracas Bay, June 30,1913 ...... 370 110.5 | 66 31 | 24.5
It will be observed that our Peruvian examples, as measured by myself, do not appear to be
larger than the type specimen from the Caribbean coast of Nicaragua, but a direct comparison of
more birds from each locality is needed.
Owing to the many uncertainties indicated, I have thought it best to discuss the American
skimmers as a unit in the biographical text, describing in detail only the typical race.
Names: Scissor-bill, Razor-bill, Sea-dog, Cutwater, Shearwater; in Spanish-speaking countries
“Rayador,”’ ‘‘Arador,’’ and ‘'Pico de Tijera’’ are recorded as vernacular names; in Brazil the
skimmer is known as ‘‘Magador,"’ ‘‘Talha-mar,’’ “‘Corta-mar’’ and ‘‘Bicorasteiro.’’ Synonyms
of the specific or subspecific names include fulva, melanura, and brevirostris.
Characters: A very long-winged, black and white larine bird, with a unique bill, the mandible
much longer than the maxilla, both compressed to knife-like thinness except at the base.
Adults of the typical or North American race in summer (sexes alike): Forehead, lores, sub-
orbital and malar regions, and entire under parts (including axillars and under wing coverts),
lateral upper tail coverts, and broad tips to secondaries and proximal primaries, immaculate pure
white; rest of plumage (except tail), including auricular region, uniform black or sooty black;
tail mostly white, the middle pair of rectrices grayish brown edged with white, the remaining
rectrices more or less tinged at tips with the same; basal half (approximately) of bill bright ver-
milion-red (in life), the mandible more scarlet, passing into orange or yellow on tomium, the
terminal half black; iris dark brown; legs and feet rich orange-vermilion (in life).
Adults in winter: Similar to summer adults but the black parts duller and more brownish and
interrupted by a broad collar of white across lower hind neck.
10 males: wing, 350-401 (381.7); tail, 116-134 (124.3); culmen, 63-72 (68.1); greatest depth
of bill, 26.5-29.5 (28.1); tarsus, 31-34.5 (32.9); middle toe [without claw], 22-24 (22.6) mm.
4 females: wing, 338-358 (346); tail, 101.5-110.5 (106.6); culmen, 52-57 (55); greatest depth
of bill, 22-24 (22.9); tarsus, 25-29 (27.6); middle toe [without claw], 18-19 (18.4) mm.
Young: Upper parts light buff, each feather with a central spot of blackish, these spots largest
on scapulars; lores and suborbital region uniform pale buff, the former, however, with a dusky space
immediately in front of eye; greater wing coverts blackish gray or grayish black, tipped with
white; secondaries white for most of their exposed portion; primaries blackish, the fourth, fifth,
and sixth (from outside) margined terminally with light buff, the four inner (proximal) ones dusky
Passing into white at tips; under parts entirely immaculate white; bill, legs, and feet dull or dusky
reddish.
Downy young: Upper parts pale grayish buff, irregularly and rather sparsely mottled with
blackish; under parts immaculate white (Ridgway, 1919, 451).
Data relating to the eggs of the South American forms are scarce and unsatisfactory. Birds of
the North American race normally lay a set of four or five boldly marked eggs, which Bent (1921,
314) describes as follows:
UE R2. OCEANIC BIRDS OF SOUTH AMERICA
The ground color is rarely pure white, but usually pale bluish white or creamy white, varying
on the one hand to pale greenish blue, almost a heron’s egg color, and on the other hand to deep
“cream buff’’ or “‘pinkish buff.’’ They are usually heavily marked with various shades of brown,
from ‘“‘tawny olive’’ and “‘burnt umber’’ to “‘seal-brown"’ or ‘‘clove-brown’’; sometimes fairly
evenly distributed as small spots, but more often in large irregular blotches or splashes in an endless
variety of patterns. Nearly all of the eggs are more or less heavily spotted or blotched, and some
are very prettily marked, with various shades of “‘lilac-gray,’’ ‘‘lavender-gray,”’ or ‘‘olive-gray.”’
In shape they vary from rounded ovate to elongate-ovate, with a prevailing tendency toward the
former shape. The measurements of 58 eggs in the United States National Museum average 45 x
33.5 mm.; the eggs showing the four extremes measure 51 x 32, 45 x 36, 41.5 x 31, and 43 x
30.5 mm.
Distribution: The range of the species as a whole includes the greater part of South America,
with the exception of the sub-antarctic south and the west coast to northward of Ecuador; the
approximate distribution of the several subspecies has been recorded above.
Around the greater part of the tropical and temperate coasts of South America
the Black Skimmer is, or formerly was, a common bird. Curiously, it seems to
be wanting along the humid shores between Ecuador and Panama, as well as
on much of the Pacific coast of Central America. The same is perhaps true of
the Caribbean side of the Isthmus, for no skimmer is listed by Sturgis (1928)
among the birds of Panama. Regarding the systematic status and exact dis-
tribution of the several subspecies, little is yet known with certainty, and even
the tentative conclusions suggested above are in part based upon inadequate
series of specimens. Under the circumstances, I have prepared these notes as a
general biography of a single American species, rather than as accounts of the
separate geographic races.
In South America, which is par excellence the continent of great rivers, the
skimmer has become much more of an inland bird than is true in any part of
its North American range. The three resident subspecies of the southern con-
tinent, as at present recognized, may in fact best be divided in accordance with
drainage systems. Thus the race intermedia belongs primarily to the long sea-
coast which receives the flow of the Pacific watershed of the Andes; the race
cinerascens 1s confined to coasts and basins of Caribbean and Amazonian drainage,
throughout which it follows the great rivers to their headwaters; in like manner,
the race intercedens is a bird of the coasts and basins that receive river waters
entering the Atlantic to southward of the eastern shoulder of the continent,
including probably the Rio Sao Francisco as well as the Paraguay-Parana
system. Finally, it appears probable that the typical race of the Black Skimmer,
which inhabits North America, migrates southward through the Antilles to
various parts of northern South America.
Although skimmers are reported along the Caribbean coast, from the Rio
Magdalena (Chapman, 1917, 222) to the vicinity of Margarita Island, nothing
seems to have been written about the nesting of the birds on the sea beaches of
either the mainland or the outlying islands. It is probable that on seacoasts
lacking isolated barrier-beaches such as abound in the eastern United States,
the skimmers have, for safety’s sake, developed a régime of breeding exclusively
on the exposed bars of great rivers during the annual seasons of low water.
Léotaud (1866, 535) states that the birds come only as migrants to Trinidad,
BLACK SKIMMER 1173
where they are seen always in flocks. In Guiana and northern Brazil they are
abundant in the estuaries and along the coast; according to both Schomburgk
(1848, 761) and Young (1928, 767), they retire to certain bars far up such rivers
as the Essequibo for their season of reproducton, while at the seashore they
are commonest during May and June which, it is noteworthy, is the period
just preceding the great floods of the rivers. From eastern Brazil southward
skimmers have been recorded from many points along the coast as far as latitude
45° S. in Patagonia, where they were observed by Darwin (Gould, 1841, 143).
Throughout this region, however, they are apparently more riparian than
littoral birds. On the River Paraguay, according to Gibson (1920, 73), they
breed between July and September, which is the low-water period, and there-
after migrate downstream and invade the Gulf of La Plata. Hartert and Venturi
(1909, 254), too, write that the skimmers in Argentina and Paraguay nest in
the same localities and at the same time as the Great-billed River Tern (Phaetusa
simplex), which is to say September or the low-water period. Sclater and
Hudson (1889, 193) also state that they appear in the neighborhood of Buenos
Aires every October, and Gibson observed flocks numbering two hundred or
more birds on mud flats at the mouth of the Rio Ajo, along the southern coast
of the estuary, on November 3. During periods of inundation, such as occurred
throughout this region in 1913, skimmers spread out and feed over large areas
of what is normally dry land (Daguerre, 1922, 261). In March, which marks
the beginning of lowering streams toward the headwaters of the great river
system that proceeds from the interior region of summer rainfall and winter
drought, the bulk of the skimmer population begins to move again upstream
in preparation for the next nesting season.
Gibson, as well as Sclater and Hudson, infers that the skimmers likewise
nest on the mud flats and islets near Bahia Blanca, Argentina, and perhaps in
the extensive ‘“‘no man’s land’’ of the Rincones, to westward of Cape San
Antonio. While the supposition sounds entirely reasonable to one acquainted
with the customs of skimmers along the southeastern coast of North America,
it is still not sufficiently supported by evidence to be accepted without further
investigation. So far as we yet know, the skimmers of eastern South America
are confined, as nesting birds, entirely to the river systems, in which their pro-
ductive cycle is correlated with the annual rhythm of precipitation and of
swelling and falling waters.
Along the west coast of South America the skimmer is a tolerably common
bird from the Gulf of Guayaquil to the neighborhood of Chiloé Island. I have
never seen it to northward of Point Santa Elena, Ecuador, and there seem to be
no records for the Pacific coast of Colombia. Among the wooded channels of
southern Chile it is presumably only a wanderer, although casually recorded
by Hellmayr (1932, 403) from as far south as the Strait of Magellan. Whether
the skimmers described from the high Andean lakes have worked their way
thither from the west coast or from Amazonian streams is still uncertain. The
only pertinent specimen I have examined was-taken on Lake Titicaca, and its
age and condition thwart subspecific identification.
1174 OCEANIC BIRDS OF SOUTH AMERICA
About all shores of the Gulf of Guayaquil skimmers are familiar birds. At
the beginning of the rainy season I have seen long lines of them quartering the
quiet, Opaque waters, and on the evening of February 24, 1925, I observed
many among a host of other sea fowl on an exposed flat off the southern point
of Puna Island. So far as my experience goes, the skimmers do not penetrate
the River Guayas far inland, and I noted only a single example well inside the
estuary. All of my observations here relate to the rainy months, however, and
at other times of year their migrations may take them much farther upstream.
Southward along the Peruvian coast the skimmer is a bird to be expected
anywhere, though it is most characteristic of quiet and sheltered regions, such
as the Bay of Pisco, or about ports like Ancén and Chorrillos, which are pro-
tected by headlands and islands on their windward sides. To southward of the
Rio Tumbez in northernmost Peru there are, of course, no rivers providing
estuaries in which this bird might forage; its habitat along the entire length
of the desert coast belongs, therefore, exclusively to salt water. Beck and I
both observed it during our field work, though nowhere in large numbers south
of the Gulf of Guayaquil.
One of the puzzling facts concerning this bird on the Pacific coast of South
America is its apparent great diminution in numbers within the last century
or so. I can think of no explanation for this unless it is implied in Delano’s
(1817, 526) statement that the skimmer is ‘excellent eating.’’ Whatever the
reason may be, both Delano and Morrell (1832, 121) record the bird from the
Lobos Islands, while Raimondi and von Tschudi include it as a resident of the
Chincha Islands, and the latter author (1844, 46; 1846, 35) states that before
the middle of the last century skimmers were abundant in the bays or roadsteads
of such ports as Ilo, Islay, Arica, and Iquique, and that large flocks were to
be seen in the Bay of Valparaiso. Certainly no such condition holds today.
Reed (1896, 211) notes that at the date of his writing skimmers were no longer
common in Chile, but were to be found sparingly along most of the coasts and
on the more southerly rivers. Hellmayr (1932, 403) also states that while the
bird now ranges over the greater part of Chile, it is nowhere common. He cites
numerous records from the seashore, the estuaries of rivers, or lagoons behind
the beaches, at various localities between Atacama and the island of Chiloé.
On April 17, 1914, Beck saw seven or eight skimmers fishing at dusk near the
wharf at Ancid, Chiloé, and on May 6 of the same year he observed a score of
the birds standing on floating strands of kelp at the same locality. Since I can
find no information regarding the nesting of skimmers along the desert coast
or at any of the guano islands, it is possible that the birds of Peru and northern
Chile are merely migrants from the river systems to northward and southward.
Dabbene (1902, 380) states that the southernmost limit of the recorded range,
in the Strait of Magellan, is based upon a purely accidental occurrence.
The skimmer is equally at home in either fresh, brackish, or salt water, pro-
vided its hunting ground be reasonably smooth and protected. It is no bird
to fight gales, despite its long wings, for it is one of the species most easily
beaten down or carried far out of its course by such storms as the tropical hurri-
BLACK SKIMMER 1175
canes. Darwin noted at Montevideo, Uruguay (Gould, 1841, 144), as I did at
Pisco Bay, Peru, that the skimmers often rest at the heads of deep and quiet
coves during the daytime, and then fly seaward in a straight line at evening.
Many other observations likewise tend to show that these birds are largely
nocturnal in their feeding habits, thus taking advantage of the hours during
which aquatic organisms approach the surface more abundantly than they do
in the daylight. The crepuscular and nocturnal activity of skimmers along the
coast of Venezuela has been noted by Robinson and Richmond (1895, 654), and
Young refers to their weird and mournful cries as heard in the darkness in
Guiana.
Whether or not the cat-like eye of the skimmer has superior powers for
collecting light is unknown, but Wetmore (1919, 195) has called attention to
the fact that the pupil in this bird contracts to an elongate vertical slit, and
that even when it is fully dilated the upper and lower points of the aperture
are marked by distinct angles so that the opening is never circular. Darwin
surmised that possibly the curious bill of the skimmer was a delicate tactile
organ of particular sensory use to the bird during its nocturnal fishing. How-
ever, Owen's dissection of materials collected by Darwin indicated that the
beak is relatively poorly supplied with nerves, and that as an organ of touch
it is not to be compared with the highly innervated bills of certain ducks and
waders.
The flight of skimmers, while they are foraging, is graceful in the extreme.
The short stroke of their wings and the eerie manner in which the body of the
bird seems to bound up and down in the air, give the impression of slow move-
ment, and yet I found in the Gulf of Guayaquil that they easily outdistanced a
launch credited with a speed in excess of 25 miles per hour. Gibson (1920, 73)
saw a skimmer pursued by several lapwings (Belonopterus), as though the latter
were attempting to rob it of fish, but the swiftness of flight and agility in turn-
ing of the former bird set the lapwings utterly at nought. The black and white
livery, the beak formation, and the excited barking voices of the skimmers all
combine to make one think of aérial beagles hot on the scent of aérial rabbits.
The simile may seem far-fetched, but the skimmers themselves are unreal and
unworldly birds, with their impractical looking forward ends, the peculiar
lightness of their lilting flight, and the calls that sound like dogs baying in a
dream.
There has been considerable recent discussion regarding the function of the
‘plowing’ habit of skimmers, that is, of the manner in which they cut the
water with the elongate lower mandible and their ‘‘purpose’’ in so doing. It
is this custom which has made the ‘‘skimming”’ of the bird usually thought of
as synonymous with feeding. Close observation will show, however, that the
skimming or plowing is done frequently, if not invariably, with the bill closed
except when the birds snap the mandibles with an audible click or open the
mouth to utter their characteristic bark. Furthermore, during the skimming
process the bill is not thrust far enough under the surface for food to be swept
into the extremely small mouth, even if it were open. The act really amounts
1176 OCEANIC BIRDS OF SOUTH AMERICA
only to a cutting of the water, rather than to ‘‘skimming.’’ Bales (1919, 83)
calls attention to the fact that the birds have a deeply fixed predilection for
barely clearing any sort of surface, so that when they fly for considerable dis-
tances over areas of mud and sand, the tip of the lower mandible is held in such
close contact that it appears almost to touch. Robinson and Richmond report
that they often saw these birds “‘skimming’’ over the thin silvery sheet of
water spread up over the sand by a breaking wave, under which circumstances
it is practically impossible that they could have been feeding. It was doubtless
observations related to these that misled Salvin and Godman (1903, 417) into
believing that the skimmers “‘will plow up the mud in search of small molluscs."’
The so-called skimming habit is properly to be regarded as a reaction of
genetic origin, primarily without purpose or adaptive meaning but, like any
other trait of congenital behavior, capable of an adaptive selection. Its fixity,
and its lack of obligatory relation to feeding, is emphasized by the discovery
of Arthur (1921, 556) that the birds ‘‘skim’’ assiduously when they are dis-
turbed or frightened, as by being driven from their nests, and that at such times
they are certainly not engaged in hunting for food but are, on the contrary,
altogether distracted from any such aim. Arthur would, in fact, entirely dis-
sociate the skimming habit from its traditional relationship with feeding, for
he believes that most of the successful fishing of the birds is done not while they
are in flight at all, but while they are standing in shallow water.
The fact may be freely accepted that skimmers sometimes fish from a standing
point of vantage; despite their very short legs, they may frequently be seen at
rest or walking in water that reaches their feathers, and striking, as better
waders such as herons might do, at the minnows which scurry across the
shallows. At the same time, the precise evidence that skimmers capture much
of their food while they are on the wing is so extensive that it cannot be gain-
said. Darwin, one of the most scrupulous of observers, wrote as follows of
observations made in May near Maldonado, Uruguay, where he watched
skimmers from the borders of a lake which had been partly drained and which,
in consequence, swarmed with small fry.
I watched many of these birds flying backwards and forwards for hours together, close to its
surface. They kept their bills wide open, and with the lower mandible half buried in the water.
Thus skimming the surface, generally in small flocks, they ploughed it in their course; the water
was quite smooth, and it formed a most curious spectacle, to behold a flock, each bird leaving its
narrow wake on the mirror-like surface. In their flight they often twisted about with extreme
rapidity, and so dexterously managed, that they ploughed up small fish with their projecting lower
mandibles, and secured them with the upper half of their scissor-like bills. This fact I repeatedly
witnessed, as, like swallows, they continued to fly backwards and forwards, close before me.
Occasionally, when leaving the surface of the water, their flight was wild, irregular, and rapid;
they then also uttered loud harsh cries (Gould, 1841, 143).
To this Gibson (1920, 73) adds the following concerning a single bird he
observed in the Province of Buenos Aires.
. . . it skimmed along the surface of the water for about 20 yards with a third of its bill
immersed; then rose, circled once or twice, and repeated the surface-glide. For a long time, fasci-
nated, I watched the dexterous and imperceptible use of wings and tail, the reflection of the bird
BLACK SKIMMER 1177
in the calm sunset-tinted pool, and the tiny furrow ploughed by its bill. And it was almost dark
when I rode away and left the Skimmer and its shadow still coming and going in the dusk.
Finally, Stone (1921, 595) watched a flying skimmer at very close range near
Atlantic City, New Jersey, while it drove its bill into the water, seized a fish
about 8 centimeters in length, and flew off with the prey held transversely. In
this instance the unequal mandibles afforded no apparent advantage, for the
bird was not ‘‘plowing’’ at the time the fish was caught.
With these several items of testimony my own observations agree and, while
watching the birds turn and cut the surface of the water again and again in the
same small area during feeding evolutions, I have come to the conclusion that
the only practical function of the flattened cutwater is to serve as a lure. Small
fishes are doubtless attracted toward the surface either by the sight of the black
and red beak moving rapidly along or, more probably, by the tiny surface
circulation which it produces. The skimmer thus baits its own trail and, upon
wheeling and returning, it takes advantage of the duped victims which have
risen to investigate. There is no evidence based upon examination of stomach
contents that the birds actually skim minute forms of life from the surface film
of the water, and I have shown above that their technique and the structure
of their mouths make this highly improbable. Only as an actual attraction to
mobile organisms could the elongate cutwater be of advantage to the birds.
In other respects, indeed, it is rather a detriment or hazard, for I myself have
seen skimmers catch their beaks on submerged twigs or standing oyster-shells,
so that their heads were jerked downward and backward, in one instance
causing a bird to turn half a somersault and tumble into the water.
The assumed function of the skimmer’s beak in creating an attraction to
small fish is open to further experimental investigation. In more or less brown,
opaque, river or lagoon waters of both Ecuador and the southeastern United
States, I have already made the test of cutting an undisturbed surface swiftly
with the slender tip of a long switch or bamboo pole. In many such instances
small fish, not previously visible, promptly rose from the murky depths, as if
in search of an insect which might have been the cause of the scarcely percep-
tible ripple. The fact that feeding skimmers so frequently ‘‘replow’’ their own
furrow tends to make some such explanation of their behavior convincing.
The following account of the breeding habits of the Black Skimmer is based
mainly upon the North American race, and is drawn in part from the study
made by Bales (1919, 83) during late June in a colony of 4000 pairs on an island
off the coast of Virginia. Here, as elsewhere, many of the skimmers nest at
such low elevations above mean sea level that spring tides sometimes sweep
over them, washing away the eggs or drowning the young birds. Four eggs
constitute the usual set, though many nests contain but three, and five are by
no means unknown. Drifting sand is a constant menace, for if the birds remain
away from the nest for any length of time on windy days, the site is rapidly
obscured and the eggs may become completely buried and lost.
All night the nesting skimmers come and go, in strong contrast with their
neighbors, the terns, which become permanently quiet as soon as darkness sets
1178 OCEANIC BIRDS OF SOUTH AMERICA
in. When a returning skimmer settles upon its eggs, it utters a liquid, cuddling
note, somewhat similar to the cluck of a hen. It next presses the sharp lower
edge of the bill on the sand outside the nesting site, an action which accounts
for the radiating lines one finds extending in all directions from skimmers’
nests. Since the bird always flies up the wind to alight, and invariably faces
the wind while incubating, these lines serve as a wind-rose and give a meteor-
ological record sometimes covering many preceding days.
When driven from their nests by the approach of a visitor, skimmers usually
exhibit behavior which is sometimes interpreted as a conflict between an im-
pulse to escape and an urge to remain upon the eggs. This, according to the
theory just suggested, results in the indecisive and crippled fluster which is
anthropomorphically interpreted as a ‘‘trick’’ to lure an intruder away. It is
unlikely, however, that such a widely known instinctive response among birds
of many groups is to be explained so simply. At any rate, the skimmers stagger
and flutter, and beat the sand with their long wings. As soon as they recover
from their first emotional debauch, they will alight and repeatedly open and
close their bills without making a sound, ‘‘as though they were swearing
under their breath."’ When the coast is again clear, so that they are free to
react to the pull of the nest, they never alight directly at the site but come down
a short distance away, afterwards toddling up on their absurdly small Chinese-
lady feet.
Young skimmers exhibit such a characteristic Charadriiform tendency to
““freeze’’ or lie motionless upon the sand which they so much resemble that
Care is necessary to avoid stepping upon them. When they first hatch, the
maxilla and mandible are of the same length, but the latter is already the longer
by the time the down gives place to the first contour feathers. During the
early part of their lives, the nestlings are fed upon regurgitated food, which is
well digested by the parents; before they are quite past the downy stage, how-
ever, they begin to receive whole fish. Arthur lists nine species commonly cap-
tured by skimmers in Louisiana, and states that the largest example he had
seen fed by parent birds to nestlings was 73 millimeters in length. Howell
(1932, 275) reports that killifishes and blennies were the common species found
in stomachs examined at the United States Biological Survey
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Worrtu, C. B., 1935. Behavior of the yellow-
billed tropic-bird. Auk, 52, p. 442.
OCEANIC BIRDS OF SOUTH AMERICA
Wricat, H. W., 1909. An ornithological trip
to Los Coronados Islands, Mexico. Con-
dor, 11:96-100.
Wynne-Epwarps, V. C., 1935. On the habits
and distribution of birds on the North
Atlantic. Proc. Boston Soc. Nat. Hist.,
40, no. 4:233-346, pls. 3-5.
Youne, C. G., 1928, 1929. A contribution to
the ornithology of the coastland of British
Guiana. Ibis (12) 4:748-781, pls. 35-42,
text-fig. 18; (12) 5:1-38, text-fig. 1; 221-
261, text-fig. 2.
ZoretL, Franz, 1928. Der ‘El Nifio’’-Strom
im Jahre 1925. Annal. Hydr. und Marit.
Meteorol. :166-175, tables 15, 16.
ADDENDA TO BIBLIOGRAPHY
Jounin, Louts, 1912. Carte des bancs et récifs de coraux (Madré-
pores). Ann. Inst. Oceanographique, 4, pt. 2: 1-7, 5 pls.
Kerwatter, C. P. pr, 1867. General examination of the Pacific
Ocean. 212 p., maps.
Smits, H. H., 1879. Brazil, the Amazons and the coast. 644 p.,
illus.
Spix, J. B. von, and Martius, C. F. P. von, 1824. Travels in
Brazil. 2 vols., illus.
IND EX
(The uniformly arranged, descriptive sections which precede each biography have not been included in the
indexing, and details of morphology and distribution should be sought primarily in them. The index will
then serve as a key to supplementary textual references.
Part I of the book (pages 1-322), which is the narrative and geographic portion, has been indexed in
considerable detail with respect to names of places, individuals, and institutions. In Part II stress has been
placed rather upon concepts relating to the natural history and behavior of birds. Authors’ names and other
personal references appearing in this part have therefore been largely omitted from the index.)
A
Aagaard, Bjarne, 234.
Abandonment of fledgling young by parents, of
albatrosses, 512, 560, 561, 581; of petrels,
593, 646, 676, 680, 708; of Pelecaniformes,
795; of tropic-birds, 807; of boobies, 829,
858.
Abingdon I., 299, 300.
Abnormalities, reaction to, of penguins, 405,
406, 490.
Abrolhos bank, 157.
Abrolhos Is., 81, 87, 130, 144, 158, 159, 161.
Absorbent plumage, of man-o'-war birds, 925,
933; of kelp goose, 947; of sooty tern, 1125.
Abundance, of Procellariiformes in southern
oceans, 489, 506, 513; seasonal, of skuas at
sea, 1034; relative, of jaegers in South
American waters, 1035, 1039.
Academy bay, 32.
Academy,’ 5.
Acaena adscendens, 221, 784.
Actitis macularia, 132, 188, 275.
Adam, Mcr., 204.
Adamastor cinereus, 74, 212, 213, 232, 649, 663,
669.
Adaptive changes in evolution of guanay, 904,
905.
Adaptive radiation, of Procellariiformes, 475;
of Pelecaniformes, 794, 795.
Adiabatic cooling of air, 121, 161, 259, 264,
268, 314.
Admiralty sound, 235.
*Adventure,’ 242.
Adventure sound, 22.
Aechmophorus major, 202.
Aextoxicum punctatum, 251.
Agassiz, Louis, 125, 135.
Age, average, of penguins, 364.
geological, of penguins, 330; of Procellarii-
formes, 471, 489, 490; of Pelecaniformes,
793; of Laridae, 1040.
of sexual maturity, 548, 549, 751, 944, 967.
Agostini, A. M. de, 234, 235, 240.
“Agua enferma,"’ 279.
Aguila lagoon, 112.
Aguja, cape, 115.
Agulhas current, 342.
Aikman, C. M., 266.
Airplanes, birds as menace to, 607.
Air speed, of wandering albatross, 569, 570.
Aisen, rio, 240, 246.
Ajaia ajaja, 166.
Alacran I., 264.
‘Albatross,’ 298.
Albatross, black-browed, 14, 250, 252, 272,
420, 421, 426; biography, 505-514; 569.
black-footed, 558.
Buller’s, biography, 524-526.
Galapagos, 39, 75, 99, 277, 303, 312, 313;
biography, 530-537; 558, 567.
gray-headed, 258, 272; biography, 514-518.
Laysan, 558.
light-mantled sooty, 72; biography, 497-505.
royal, 239, 250, 550; biography, 575-584; as
resident of Tierra del Fuego, 577.
sooty, biography, 494-497; 545, 568.
Tristan wandering, biography, 571-575.
wandering, 72, 165, 180, 213, 234, 250; bi-
ography, 538-571; 576, 609, 627.
white-capped, biography, 526-530.
yellow-nosed (= Diomedea chlororhynchos),
75, 81, 423; biography, 518-524.
yellow-nosed (= Diomedea chrysostoma),
13516; 22.
Albatrosses, general account of, 489-494; as
food, 551, 574.
Albemarle I., 32, 144, 296, 298, 300.
Albinism, 405, 408, 419, 437, 460, 588, 643, 669,
709, 710, 1069.
Alcatrazes Is., 161.
Alexander, W. B., 35, 88, 154.
Algae, brown, 61; green, 63.
Algarrobo I., 461.
Alle alle, 50, 781, 787.
Allee, W. C., 339, 340.
Allen, A. A., 340.
Allen, W. E., 62, 279, 282.
Alluvium, in coastal waters of Guiana, 129;
carried to sea by Amazon, 135.
Almirante Brown bay, 17, 19.
Aloofness, interspecific, of king penguin, 352,
353; of emperor penguin, 363.
Altitudinal range of nesting petrels, 656.
Amapé, river, 134.
Amaral, Afranio, 161, 162.
Amazon, river, 37, 38, 41, 42, 45, 47, 89, 90, 112,
130, 134, 135, 138, 139, 281, 305; color of
water, 126; driftwood on banks of, 135;
tides in, 135; absence of delta, 135; currents
off, 135; alluvium carried to sea by, 135.
[1211 ]
1212
American Geographical Society, 27, 34, 300.
American Museum of Natural History, 1, 27,
31; library of, 34; 209, 222, 251.
Amortajada I., see El] Muerto.
Amotape mountains, 280, 285, 286, 307.
Amphisbaena ridleyi, 148.
Amsterdam I., 215.
Anas bahamensis rubrirostris, 187.
cinerea, 954.
cyanoptera, 187.
flavirostris, 187, 202.
georgica, 222, 948.
specularis, 202.
specularioides, 202.
spinicauda, 187, 202, 219, 222, 941, 949.
versicolor, 187, 202.
Anatidae, 207, 327, 941.
Ancén, 9, 10.
Ancid, 11, 248.
Anhinga, 140, 166, 291, 793, 911, 913.
Anilocra plebia, 465, 878.
Anotis minutus, 80, 81, 124, 148, 150, 176, 218,
1149, 1150.
Minutus atlanticus, 1160.
minutus diamesus, 319, 1163.
stolidus, 80, 81, 101, 124, 146, 148, 150, 151,
176, 181, 213, 214, 261, 1149.
stolidus galapagensis, 1159.
stolidus ridgwayi, 319, 1158.
stolidus stolidus, 1150.
Anseriformes, 327, 941.
Anson, Lord, 244.
Antarctandes, 218.
Antarctic archipelago, 70, 109, 197, 218, 221,
229-233.
Antarctic convergence, 66, 67, 68, 69, 70, 71, 72,
165, 434, 490, 623, 640, 756.
Antarctic zone, 65, 67, 68-71, 72, 76, 92, 93,
108, 219, 222, 602, 613, 622, 624, 628, 636,
691, 702, 765, 785, 1001, 1095, 1105.
‘Antarctica,’ 17, 18, 19, 20.
Antarctomysis maxima, 377.
Anthony, A. W., 4.
Anthus antarcticus, 222, 592, 753, 1031.
Antillean arc, 35.
Antipodes Is., 765.
Antofagasta, 10, 96, 263, 267, 285.
Afio de abundancia, 285.
Afio Nuevo Is., 235.
Aphriza virgata, 275.
Apody, river, 46.
Aptenodytes forsteri, 71, 225, 232, 354, 388.
patagonicus, 76, 201, 208, 222, 225, 232, 343.
Aracaty, 139.
Araguary, river, 134.
Aramides cajanea, 166.
Aramus scolopaceus carau, 187.
Araucaria, 231.
Arauco, 36, 200; gulf of, 252, 253, 254.
Arctocephalus australis, 169, 276.
Ardea cocoi, 166.
Argentino, lago, 196.
INDEX
Arica, 10, 96, 106, 264, 267, 271, 286.
Aristotelia maqui, 251.
Arstogene, 615.
Artemia, 188.
Aruba I., 116, 121, 122, 123, 144.
Ascension I., 32, 77, 80, 81, 86, 149, 151-155,
168, 171, 173, 175, 176, 178, 181, 271; type
locality of four sea birds, 152.
Aspergillosis, 903.
Assu, river, 46, 140.
Astor, Vincent, 31, 467.
Atacama desert, 264.
Atlantic equatorial current, 123.
Atlantic tropical zone, islands of, 145-155.
Atlantisia rogersi, 217.
Atoll, Rocas Reef, only, in South Atlantic, 145.
Atrato, river, 110, 111, 120.
Atriplex, 260, 262.
Attaprion, 624.
Auks, resemblance of diving petrels to, 771, 780.
Austin, O. L., Jr., on arctic tern, 1104.
Aves, islas de, 122.
Avicennia nitida, 132.
Azorella, 725.
Azores, 80, 159, 255.
Azuero, peninsula de, 319.
B
Bachelor bands, of king penguin, 353.
Bacteria of sea water, 61, 62.
Bahama Is., 149.
Bahia, 23, 41, 42, 87, 130, 141, 144, 156, 157,
168, 200, 263.
Bahia Blanca, 41, 92, 190, 192.
Baily I., 19, 241.
Bait, birds used as by fishermen, 663, 664.
Baiting of sea birds, as method of observation
and collection, 507, 517, 528, 564, 608, 647,
663, 664, 677, 699, 712, 754.
Baker canal, 240.
Balboa, 9.
Ball, H. D., 265, 266.
Ball, John, 138, 263.
Ballén, Francisco, 28, 31.
Ballestas Is., 274, 287.
Bamboo, 134, 137, 248, 298, 314.
Banda Oriental, 184, 185.
Bangs, Outram, 35, 315.
Banishment of fledgling young, by adult steamer
ducks, 967.
Barbados, 23, 25, 123, 153.
Barclay, W. S., 271.
Barima point, 127.
Barlow, Nora, 183.
Barnevelt Is., 241.
Barrancas, 127.
Barrere, Pierre, 133, 134.
Barrington I., 280, 300.
Bartramia longicauda, 219.
Baudé, rio, 314; serrania del, 314, 316.
Bayoneta I., 321.
INDEX
‘Beagle,’ 150, 153, 158, 181, 183, 184, 196, 237,
243, 246, 248, 264, 268, 296.
Beagle channel, 13, 15, 16, 18, 237, 239, 240.
Beauchéne I., 203.
Beaufort scale of wind velocity, 48, 660.
Beck, R. H., autobiographic notes, 3-7; tech-
nique of bird collecting, 7, 8; journal of
Brewster-Sanford expedition, 8-25; tribute
to, 24; 94, 99, 158, 186, 188, 189, 197, 206,
235, 243, 245, 248, 250, 258, 274, 275, 276,
304.
Beck, Mrs. R. H., 5, 6, 7, 8, 11, 12, 14, 21;
tribute to, 24.
Beebe, William, 97, 129.
Beeches, sub-antarctic, 231, 234, 238, 239, 240,
242, 244, 248.
Beetles, at St. Helena, 179; at Gough, 211; at
South Georgia, 222.
Behavior patterns, as indications of relation-
ship, 492, 794, 871, 872.
Belcher, C. F., 123.
Belem, 139.
Bellin, S., 133.
Bellingshausen, F. von, 223.
Bellingshausen I., 225.
Bellingshausen sea, 93.
Belonopterus chilensis, 170, 187, 202.
Bendire, Charles, 3.
Benguela current, 77, 83, 89, 108, 443.
Bennett, A. G., 207, 208, 219, 228, 231, 232.
Bent, A. C., 5, 261.
Bergmann’s law of geographic relation between
bulk and thermal economy, 358, 456, 572,
1108, 1147.
Berkeley sound, 21.
Berlin Zodlogical Museum, 33.
Bermejo I., 189.
Bermuda, 89, 149.
Bertrand J., 15, 16, 17, 18.
Bigelow, H. B., 60, 97.
Bill, disharmonic growth of, among whale-
birds, 614, 615.
specialized use of, by oyster-catchers, 978,
993; by skimmers, 1176, 1177.
Bill-clattering, of albatrosses, 522, 523, 535,
536, 537; of man-o'-war birds, 936.
Bindloe I., 299, 300.
Bio-Bio, rio, 252, 253.
Biographies of birds, plan of, 327, 328.
Bird 1. (Patagonia), 196.
Bird-banding, and bird-marking, discoveries
from, 369, 390, 404, 496, 508, 546, 604,
664, 712, 769, 805, 891, 1104, 1143.
Bird collecting, Beck's methods of, 7, 8, 19, 21.
Birdless oceanic regions, 88, 89.
Birds, described as new, 328.
of Antarctic zone, 71, 180, 243; of pan-ant-
arctic realm, 76; of pan-tropical realm, 78-
81; of Sub-antarctic zone, 74, 75, 81; of
Sub-tropical zone, 79.
Blanca, isla, 274.
Blanco, cape (Argentina), 20, 195, 284.
1213
Blanco, cape (Peru), 95, 303.
Bleaching effect of antarctic light, 403, 587,
889, 1018.
Bleaker I., 22.
Blofeld, J. H., 180.
‘Blossom,” 32, 145, 148, 153, 173, 174, 176, 181.
Blue water, off eastern Brazil, 140.
Boatswain-bird I., 153, 154.
Boca Grande, 124, 127, 128.
Bocas de Dragos, 113, 119, 123.
Body fat, as source of subsistence for abandoned
fledglings, 561, 680.
Body temperature, of various birds, 873, 1005,
1025, 1109.
Bognoly, J. A., 299.
Boldoa fragrans, 251.
Bom Abrigo I., 162.
Bonaire I., 116, 121, 122.
Bonpland, A. J. A., 118.
Boobies, general account, 827-829.
Booby, blue-faced, 60, 99, 123.
blue-footed, 100, 281, 304, 305, 307, 309, 311,
312, 314, 315; biography, 829-838.
brown, 59, 91, 123, 159, 162, 167; biography,
854-859; 1118.
Colombian, 314, 315, 318; biography, 859-
861.
masked, 261, 312, 314; biography, 846-853.
Peruvian, 250, 252, 276, 281, 293.
red-footed, 123, 176, 179, 302; biography,
861-870.
white, 285.
Booby I., 146, 148.
Bordones, 118.
Bore, at mouth of Amazon, 135, 136.
Boston Society of Natural History, 33.
Bosworth, T. O., 283.
Botaurus pinnatus, 166.
Bougainville, Baron de, 204.
Bouvet, Pierre, 233.
Bouvet I., 66, 69, 73, 93, 209, 233-234.
Bowman, Isaiah, 34, 108, 268.
Boyson, V. F., 204, 205.
Braathen, Christian, 32.
Branco, cape, 156.
Branner, J. C., 143.
Bransfield strait, 229.
Brattle I., 300.
Brazil current, 66, 69, 82, 83, 87, 88, 158, 161,
543, 1140.
Brazilian basin, 159.
Brazilwood trees, 173, 174, 176.
Brecknock pass, 13, 16.
Brecknock peninsula, 235.
Breeding grounds, undiscovered, of petrels, 714,
715, 739, 758; of gulls, 1051, 1075, 1076.
Breeding ranges, geographical relationships in
Magellanic South America, 197, 198.
Breeding season, of continuous type, 151, 456,
457, 458, 776, 800, 818, 821, 856, 866, 877,
905, 931, 938, 1047, 1064, 1087, 1088, 1152,
1153, 1158.
1214 -
of fixed or climatic type, 456, 522, 857, 1159,
1162.
irregularity of among sub-antarctic petrels of
restricted migratory range, 672.
multiple, 459, 1154.
prolonged, of pan-tropical petrels, 686, 688.
variable or sporadic, 812, 1125; variation
of, according to latitude, 1125.
Brewster, F. W., 2, 5, 27.
Brewster-Sanford expedition, 1, 3, 94, 99, 186,
197, 235, 243, 250; narrative of, 8-25; size
of collections, 24.
Brisotes de Santa Marta, 117.
Bristol I., 224, 225.
mBriteeyile
British antarctic expedition of 1901, 172.
British Museum (Natural History), 33.
Brood, small size of in South Georgian teal,
950, 951.
Broodiness, relative, in the two sexes, 397, 431,
806, 887, 888, 931, 932, 978.
Brooding behavior, of penguins, 341, 348, 350,
360, 371, 374, 396, 397, 412, 431, 435, 449,
459; of Procellariiformes, 478, 479, 503,
504, 523, 529, 535, 591, 592, 657, 680; of
tropic-birds, 800, 805, 806; of pelicans, 814,
815, 826; of boobies, 835, 836, 843, 850,
852, 853, 858, 866, 867; of cormorants, 887;
of man-o’-war birds, 932; of steamer ducks,
962; of sheath-bills, 1004; of skuas, 1019;
of terns, 1167; of skimmers, 1178.
physiological basis of, 341.
Brood-patch, lack of in boobies, 852.
Brooklyn Museum, 25, 27, 33.
Brooks, S. C., 88, 89.
Brown, R. N. R., 210, 213.
Brown, W. W., Jr., 315.
Briggen, J., 267.
Brunswick peninsula, 238.
Bryce, James, 162, 205, 206, 238, 239, 245, 250,
D5 ae
Bucay, 304.
Buckland monte, 235.
Budi, laguna del, 250.
Buenaventura, 44, 144, 314, 315, 316.
Bueno, river, 249, 250.
Buenos Aires, province of, 183, 186, 188, 191, 201.
Buenos Aires, likened to Chicago, 37; origin of
name, 48.
Bullock, D. S., 32, 251, 252.
Bullying of other birds by shearwaters, 688.
Burdwood bank, 92, 218.
Burmeister, Hermann, 184.
Burrow, function of in life of penguins, 449.
occupation of during successive years by
identical pairs of petrels, 679.
occupation of by rival pairs of petrels, 680.
use of, of other species, by petrels, 746; by
tropic-birds, 800; by terns, 1145.
Burrowing, method of, by penguins, 447, 459;
by petrels, 644, 645, 656, 658, 659, 670,
671, 676, 737, 778, 785.
INDEX
Burtis, Sam, 3.
Butorides striatus, 166.
Byrd, R. E., 32.
Byrd antarctic expedition, 32.
Byron sound, 22.
C
Cabello, puerto, 113.
Caching of food by skua, 1030.
Cactus, 116, 118, 119, 121, 122, 301, 303, 308,
311.
Caesalpinia, 175.
Cagarra I., 160.
Calcanhar, cape, 140, 141.
Caldera, 264, 268.
Caleta Olivia, 195.
Calidris canutus rufus, 188.
leucophaea, 275.
California, gulf of, 82.
California, university of, 5.
California Academy of Sciences, 33.
California current, 82, 669.
Callao, 9, 10, 27, 28, 96, 97, 98, 263, 276, 277,
282.
Calling of young in egg, of petrels, 680; of
tropic-birds, 806; of pelicans, 815.
Calsoene I., 135.
Camachancas, 263.
Camana, 272.
Camarones, bahia, 192, 194; river, 264.
Camelotes, 181.
Camera, motion-picture, importance of, 329.
Cami, lake, 201, 235, 239; probable breeding
ground of royal albatross, 577.
Camouflage, of whale-birds in marine environ-
ment, 626.
Campbell, Ruth M., 34.
Campbell, Stuart, 259.
Campos, 157.
Cafiadon del Puerto, isla del, 196.
Canal do Sul, 136.
Cananéa I., 161, 162.
Cancer polyodon, 672.
Candelmas I., 224, 225.
Cangrejales, 185, 189.
Cangrejo I., 126, 321.
Cannibalism, of pelicans, 814, 816; of skuas,
1019, 1020, 1029; of terns, 1112.
Cape Horn, 12, 14, 18, 37, 47, 66, 70, 73, 87,
109, 185, 193, 198, 199, 200, 201, 202, 218,
237, 240, 243, 263, 305; rounding of, by
Beck, 15.
Cape Horn drift, 92, 93.
Cape Pigeon, 58, 72, 90, 93, 165, 167, 224, 225,
231, 234, 243, 250, 252, 272, 487, 558, 571;
biography, 601-610; 624, 636.
Cape Verde Is., 25, 26, 27, 51, 52, 57, 80, 89,
148, 149, 159, 179.
Capella paraguaiae paraguaiae, 187.
Caracas Is., 118.
Cardozo, ilha do, 161, 162.
Cariaco, gulf of, 113, 118, 119.
INDEX
Caribana, point, 112.
Caricari, point, 115.
‘Carnegie,’ 66, 98.
Carnegie Museum, 33.
Carnivorous habits, of petrels, 594, 595, 598,
609.
Caroline I., 13, 16.
Carr, C. W. R., 212.
Carrasco, 23.
Carriker, M. A., Jr., 113, 114, 120.
Carrion eating, of petrels, 486, 487, 488, 594.
Cartagena, 144.
Casablanca, 155.
Casaya I., 321.
Castafién, J. C., 289, 295.
Castilho I., 161, 162.
Castillos Is., 169.
Castro, 248.
Catapulting, of penguins, 357, 358, 385, 400,
410, 421.
Catedral, roca, 259.
Catharacta lonnbergi clarkei, 225.
skua, 71, 213, 1006.
skua antarctica, 74, 200, 208, 1010, 1020.
skua chilensis, 74, 189, 200, 1009, 1013.
skua lénnbergi, 222, 227, 232, 233, 1010,
1023.
skua maccormicki, 232, 233, 1009, 1016.
skua skua, 1009, 1012.
Cats, at St. Helena, 180; at Tristan da Cunha,
217.
as enemies, of petrels, 648, 746; of tropic-
birds, 180, 802; of pelicans, 827.
Cave-nesting, of penguins, 454, 457, 462, 470;
of petrels, 671, 734; of tropic-birds, 805; of
cormorants, 897.
Cavendish, Captain, 179.
Caviana I., 136.
Cayenne I., 133.
Ceara, 45, 46, 139, 140, 141.
Celerio lineata, 308.
Centinela I., 124.
Cephalopods, as bird food, 91, 92, 232, 451,
562, 563, 620, 1132, 1148.
diurnal vertical range of, 806.
Ceratixodes putus, 888.
Cerro Amarillo, 259, 262.
Chacao narrows, 248.
‘Challenger,’ 86, 148, 150, 151, 214, 216, 217.
Chancay, 286, 287.
Chanduy, winds of, 303, 304.
Chafiaral, 258.
ChapeirGes, 159, 160.
Chapera I., 321.
Chapin, J. P., visits to Galapagos, 31, 32; to
Juan Fernandez, 31; to San Felix and San
Ambrosio, 31; to Hormigas de Afuera ls.,
32; 256, 260, 261, 276, 277.
Chapman, F. M., dedication page, 6, 24; ex-
plorations of, 29, 30, 31; field work, 197;
34, 113, 207, 242, 243, 246, 247, 248, 252,
257, 270, 271, 275, 306, 312, 314.
1215
Charadriiformes, 186, 327; general account,
972-973.
Charadrius collaris, 166, 187.
falklandicus, 188.
sanctae-helenae, 179.
semipalmatus, 275.
Charcot, Jean, 231.
Charles I., 144, 298, 300, 303.
Chascomis, lake, 31, 185.
Chatham bay (Cocos), 317.
Chatham I., 144, 298, 300.
Chauna torquata, 187.
Cherrie, G. K., 30
Chico, rio, 195.
Chilca, 10.
Chilco, 251.
Chiloé I., 11, 30, 198, 199, 244, 245, 247, 248,
250, 252.
Chimanas Is., 118.
Chimborazo, Mt., 306.
Chincha Is., 31, 96, 98, 155, 265, 274, 287, 289,
291, 292, 295.
Chionididae, 323, 327, 999.
Chionis alba, 6, 202, 208, 222, 227, 232, 895,
999, 1000.
minor, 1004.
Chira, river, 28, 280, 281, 282, 283.
Chiralite,’ 28, 284.
Chirambira, point, 319.
Chlidonias nigra surinamensis, 1089.
Chloéphaga, 326.
hybrida, 199.
hybrida hybrida, 942.
hybrida malvinarum, 199, 208, 945.
melanoptera, 202.
Picta, 202, 206, 222, 946.
poliocephala, 202, 244.
rubidiceps, 208, 946.
Chocé, Colombian, 309, 313, 314.
Choiseul sound, 203.
Chonos archipelago, 246.
Chorillos, 9.
Christmas sound, 13.
Chromis crusma, 915.
Chthanalus cirratus, 993.
Chubir, 192, 199, 249; rio, 193, 194, 195.
Chun, Carl, 234.
Churruca bay, 242.
Chuy, river, 168.
Ciénaga, Boca de, 114.
Ciénaga Grande, 113, 114.
Cinclodes, 207, 241, 247, 257.
taczanowskii, 99.
Cinders, in petrel stomachs, 759.
Ciudad Bolivar, 127, 128.
Cladornis, 334.
Claphrium simarubra, 866.
Clarence I., 218, 228.
Clark, A. H., 123.
Clark, John, 292.
Clarke, W. E., 213, 226, 227.
Clayton, William, 204, 207.
1216
Clerke rocks, 218.
Cleveland, B. D., 26.
Cleveland Museum of Natural History, 33;
South Atlantic expedition of, 32, 145, 153,
173, 180, 181.
Climatic regions, 39-50.
Cloud canopy, at St. Helena, 178.
Cobbwh Av. 22.
Coccolobis uvifera, 857.
Coccyzus ferrugineus, 317.
Coche I., 123.
Cochon [., 21.
Cockburn channel, 13, 16, 237.
Cock-feathering of females, of man-o’-war
birds, 922, 925.
Cockroach I., 23.
Coconuts, 163, 298.
Cocos I., 44, 102, 103, 108, 298, 302, 313, 314,
57-5195
Codera, cape, 37, 118.
Coihue, 247, 446.
Coker, R. E., 35, 98, 294, 295.
Collecting, need for additional, 324.
Collier, W. M., 30.
Colmenares, cerro, 251.
Colnett, James, 97, 296, 298, 319.
Colonial nesting habit, possible reason for, of
cormorants, 904.
Color characters, of skuas, 1008, 1009, 1010,
1012, 1018, 1021.
Color phases, cycles in, of petrels, 643, 655,
696, 697.
of petrels, 706, 707, 709, 710; of tropic-birds,
804; of boobies, 863, 864; of jaegers, 1037,
1038, 1039; of noddies, 1149.
Color preferences, of penguins, 405.
Colorado, rio, 49, 189, 305.
Coloration, obliterative, of whale-birds, 625,
626; of female kelp goose, 943, 944, 946; of
young oyster-catchers, 978; of young gulls,
1063.
Columba livia, 257.
Colymbus chilensis, 170, 187, 202.
occipitalis, 208.
rolland, 74, 208.
Comer, George, 32, 209, 210, 211; on Gough I.
wandering albatross, 574.
Comodoro Rivadavia, 194, 195.
Compafiia Administradora del Guano, 27, 28,
31, 293, 294, 295.
Compensation, biological, in relation to size of
egg and of clutch, of terns, 1111.
Competition, interspecific, between pelicans
and boobies, 823; of upland goose with
sheep, 947.
intraordinal, of Procellariiformes, 475; among
albatrosses, 507, 508.
Comprida, ilha, 162.
Concepcién, 46, 253; bay of, 273.
Concepcién I., 314.
Conditioning, to sound of bell, of gulls, 1070.
INDEX
of boobies, to a single offspring, 853; of
sheath-bills to specific number of young,
1004; of skuas to specific number of eggs or
oung (single), 1027, 1028.
Condor, Andean, 190, 275, 281; as enemy of
guanay, 907, 908.
Cone I., 209.
Conflict between responses caused by presence
of two young, 1027, 1028.
Conjugatae, 63.
Connétable Is., 133, 134.
Conspicuousness, of male kelp goose, 944, 946,
947; of oyster-catchers, 977, 978, 980, 992,
993.
Convergent evolution, of diving petrels and
auks, 781, 787, 788.
Conway bay, 32.
Cook, James, 74, 223.
Cook I., 224, 225.
Cookilaria, 713.
Copeland, R., 173.
Copepods, 78.
Copiapé, 46, 49, 253, 263, 268.
Coppinger, R. W., 253.
Coquimbo. 96, 249, 264.
Coral clumps, 146.
Coral-heads, 159.
Coral reefs, 141, 142; at Abrolhos Is., 158.
Corallina chilensis, 877.
Corcovado, gulf of, 30, 246, 247, 248.
Cordes, Simon de, 74.
Cordova, Antonio de, 238.
Corentyn, river, 126.
Cormorant, bigti4, 120, 127, 140, 250, 272, 307;
biography, 909-915.
flightless, 303; biography, 916-919.
Fuegian, biography, 915-916.
Peruvian, 250, 252, 266, 293, 304.
red-footed, 99, 251, 272.
Cormorants, general account, 870-873; as food,
877.
Corn, Indian, 286, 314.
Coro region, 42, 115, 116.
Gao gulf of, 249.
Coronation IJ., 225.
Coronel, 10, 252.
Coronilla Is., 168, 170.
Corpus striation, rdle of in behavior of alba-
trosses, 492.
Corral, 10, 11, 199, 200, 250.
Correia, J. G., 6, 197; work at South Georgia,
26; at Cape Verde Is., 26, 27.
Correlation, between food supply and size of
brood reared, 844.
between size and rate of growth, in penguins
and albatrosses, 581.
of color phase with range, of petrels, 588.
Corrientes, cape, 186, 189, 316.
Cory, C. B., 123.
Coscoroba coscoroba, 185, 187, 202.
Counany, river, 134.
Courid4, 112, 130, 132, 134, 163.
INDEX
Courtship, of penguins, 340, 349, 350, 359, 373,
391, 392, 394, 411, 430, 459, 462; of alba-
trosses, 492, 513, 522, 535, 551, 552, 553,
554, 555, 558, 559; of petrels, 590, 599, 628,
645, 659, 660, 725; of diving petrels, 775,
776, 790; of tropic-birds, 797; of boobies,
835, 836, 843, 850, 852, 857; of cormorants,
872, 873, 887, 890, 894, 906, 907; of man-
o'-war birds, 931, 932; of kelp goose, 947;
of steamer ducks, 962; of oyster-catchers,
984; of phalaropes, 994; of sheath-bills,
1004; of skuas, 1026, 1029; of gulls, 1048;
of terns, 1124, 1155.
Covadonga cove, 258.
Cowley, W. A., 300.
Cowper, William, 173.
Coy inlet, 18.
Crabberies, of Bahia Blanca, 189.
Crabs, land, 315.
Cradock, Christopher, 53.
Craters, at Tristan da Cunha, 214; at Inacces-
sible, 216; at Candelmas I., 224; at Albe-
marle and James Is., 300.
Crawshay, Richard, 193, 235, 237, 239, 242,
244.
Creagrus furcatus, 99, 101, 302, 320, 1041, 1048,
1086.
Cricket I., 23.
Cristaria insularis, 260, 261.
Crocethia alba, 188, 248.
Crocker, Templeton, Pacific cruise of, in aid of
Museum's work, 31, 32; 256, 261.
Crossman I., 300.
Crosthwait, H. L., 240.
Crowberry (diddle-dee), at Tristanda Cunha, 214.
Crozet Is., 69.
Crude oil, destruction of birds by, 596.
Ctenomys, 241.
Cuarenta Dias, 242.
Cuellon, 11.
Cuenca, 305.
Culpepper I., 299, 300, 302.
Culture plants, at Fernando Noronha, 148; at
Ascension, 152.
Cuman4, 31, 116, 118, 119.
Cumberland bay, 49, 222.
Cunningham, R. O., 184, 193.
Cupica bay, 316.
Curacao, 116, 121, 144.
Curiosity, of penguins, 381, 405, 416; of alba-
trosses, 507; of tropic-birds, 804; of steamer
ducks, 968; of skuas, 1030; of terns, 1096,
1146, 1165.
Curlew, Eskimo, 186.
Hudsonian, 140, 247, 275, 306.
“Current doldrums,’’ 296.
Currents, cool, specific effect of upon the dis-
tribution of petrels, 598, 650.
off eastern Tierra del Fuego, 18, 237; in
western Caribbean, 114; at South Shet-
lands, 229; at Galapagos Is., 296, 297, 298;
at Gorgona I., 315.
1217
Cushman, J. A., 87.
Cyathea Copelandi, 174.
Cycle, annual life, variation in due to latitude,
etc., among penguins, 369, 370, 376, 377,
411, 423, 425, 427, 430, 431, 435, 437, 444,
445; among albatrosses, 537, 574; among
terns, 1125, 1126, 1127, 1153.
seven-year climatic, on west coast of South
America, 822.
Cyclic fluctuations in abundance of birds, 822,
824, 842.
Cyclonic storms, 48, 52; transportation of birds
by, 53, 54, 58.
Cygnus melancoriphus, 187, 202.
‘Cypress,’ 28.
D
Dabbene, Roberto, 35, 72.
Dagua, rio, 316.
‘Daisy,’ 25, 26, 138, 145.
Daly, A., 229.
‘Dana,’ 65, 90, 91.
Dancing, of albatrosses, 492, 558, 559, 560; at
sea, 508.
Daption capensis, 71, 99, 102, 165, 167, 188,
222, 223, 225, 227, 232, 234, 235, 258, 601.
Darien, gulf of, 110, 114, 120, 144; isthmus of,
313, 316.
Darwin, Charles, 89, 147, 150, 153, 158, 177,
181, 183, 184, 191, 196, 206, 219, 237, 238,
242, 243, 245, 246, 247, 248, 253, 264, 273,
296, 297, 298.
Darwin, cordillera, 235, 240.
Darwin, mount, 240.
Darwin bay, 32.
Darwin channel, 30, 243.
Daule, river, 305.
Daylight, effect of, upon fledgling petrels, 681;
upon breeding petrels, 738.
length of, in relation to physiological
rhythms, 361.
Deacon, G. E. R., 35, 48, 65, 66.
Death, natural, in birds, 372.
Deceit I., 241.
Deception I., 32, 93, 219, 228, 229.
Deer I., 190.
Defecating reaction, of sheath-bills, 1005, 1006.
Delano, Amasa, 151, 287.
Delgada, punta, 18, 20.
Delgado, puerto, 11.
Delta, of Atrato, 111; of Orinoco, 124-128;
absence of, at mouth of Amazon, 125, 135.
Demerara, 129.
Dendrocygna bicolor bicolor, 187.
viduata, 187.
Dendroica petechia aureola, 317.
Dendroseris, 260.
Denis, Pierre, 39, 141.
Depth, of frictional influence, 82.
of littoral water, as bearing upon bird life,
ais
1218
Deseado, river, cape, and port, 19, 20, 192, 194,
195, 196, 198, 199, 200.
Desolacién I., 237, 242, 243.
Desvelos bay, 192.
‘Deutschland,’ 224.
Devil's I., 133.
Diablotin, Beck's hunt for, 24; 692.
Diadem mountain, 14.
Diana's peak, 177, 178.
Diatoms, 61, 62, 63, 77, 93, 100, 270, 279, 282,
293; uniformity of, in Humboldt current,
97.
Dibulla, 115.
Dichromatism, in penguins, 402, 418; in Pro-
cellariiformes, 479, 537, 669, 674, 696, 697,
703, 705, 707; percentage of white phase in
breeding population of giant fulmar, 588;
in young noddies, 1159.
Dicksonia, 256.
Diddle-dee, 205, 214, 447.
Diego Alvarez I., 203.
Diego Ramirez Is., 13, 16, 17, 18, 201.
Differential growth, in penguins, 351, 357; in
whale-birds, 611; in ontogeny of Pelecani-
formes, 794; in skimmers, 1178.
Dimegaly, in penguin eggs, 375, 423.
Dimorphism, sexual, in penguins, 456; in Pro-
cellariiformes, 479, 530, 558, 580, 586, 587,
588, 589, 765, 766; in Pelecaniformes, 795,
820, 833, 834, 848, 880, 931; in kelp goose,
943; in phalaropes, 994.
Dinoflagellates, 282.
Diomedea albatrus, 101, 571.
bulleri, 524.
chionoptera, 547.
chlororhynchos, 74, 213, 518, 575.
chrysostoma, 76, 222, 232, 298, 514.
epomophora, 74, 75, 188, 201, 239, 545, 548,
550, 563, 575.
exulans, 232, 258.
exulans dabbenena, 74, 75, 213, 571.
exulans exulans, 71, 222, 538.
irrorata, 99, 101, 312, 530.
melanophris, 76, 167, 188, 208, 213, 222, 225,
232, 258, 505.
nigripes, 559.
regia, 576.
rohui, 550.
sanfordi, 576.
Diomedeidae, 327, 489.
Directional reaction of young petrels toward
water, 680.
Discoloration of ocean waters by rivers, 129,
130.
Discovery’ investigations, 35, 65, 69, 74, 92,
174, 224.
Disease, pandemic, of guano birds, 102, 304;
of penguins, 451, 452; of shearwaters, 669;
of pelicans, 818, 822; of cormorants, 895,
896, 903, 904.
Disgorging of food, as reaction to disturbance
or fright, 680, 816, 823, 826, 1116, 1146.
INDEX
Distribution, of penguins, 342, 343, 408, 409,
410, 411, 417, 433, 434, 439, 440, 441, 442,
443, 444; of genus Spheniscus, 467; of alba-
trosses, 490, 509, 510, 534, 545, 547, 550,
551, 563; of royal albatross in South
America, 576-579; of whale-birds, 612, 613,
616, 617, 618, 620, 623, 629, 630, 631, 632;
of tropic-birds, 796, 799, 801; of pelicans,
807, 808, 810; of boobies, 833, 840, 842,
848, 849, 855; of cormorants, 870, 871, 874,
875, 878, 882, 883, 897, 902, 911, 912, 913;
of man-o'-war birds, 920-922, 928, 929,
930; of steamer ducks, 960, 961, 971; of
Charadriiformes, 972, 973; of oyster-
catchers, 973, 976, 984, 986, 989, 990, 991;
of sheath-bills, 1001, 1002; of skuas, 1014,
1015, 1017, 1018; of gulls, 1040, 1041,
1045, 1046, 1050, 1051, 1053, 1054, 1059,
1060, 1073, 1075, 1079, 1080, 1083; of
terns, 1089, 1090, 1091, 1093, 1095, 1096,
1098, 1099, 1100, 1101, 1102, 1103, 1105,
106; V107;, WLO8S EES 113 eS Gs
TITS TGS W208 1225 1 42S Sie
11325 1033; 1134, 1135; 11375 11385) 1s95
1140, 1141, 1142, 1143, 1144, 1148, 1149,
1150, 1151, 1158, 1160, 1161, 1162, 1163,
1164, 1166, 1168; of skimmers, 1172, 1173,
1174.
Distribution, bipolar, of fulmar group of
petrels, 474; of a single species of skua,
1006.
circumpolar, of snow petrel, Adélie penguin,
south polar fulmar, 635; of high antarctic
organisms generally, 1018.
discontinuous, of Procellariiformes, 475, 734.
of noddies as correlated with isotherms of
surface water, 1153.
Diurnal, feeding of petrels, 738.
nest-relief, of petrels, 706.
rhythm in régime of bird behavior, 546, 805,
815, 858, 891, 899, 905, 908, 936, 1081.
Diving, loss of, in man-o'-war birds, 795.
of penguins, 384, 400; of Procellariiformes,
486, 607, 621, 634, 635, 636, 639, 640, 652,
660, 672, 687, 746, 751; of tropic-birds,
799, 806; of pelicans, 817, 825; of boobies,
837, 839, 845, 851, 856, 869; of steamer
ducks, 959, 960, 964; of oyster-catchers,
978, 982; of terns, 1089, 1091, 1093, 1097,
1109, 1110, 1118, 1140, 1146.
Diving petrel, Coppinger’s, biography, 791-
792.
Falkland, 21; biography, 788-790.
Magellanic, biography, 779-783.
Peruvian, 250.
South Georgian, 67; biography, 783-788.
Tristan, biography, 790-791.
Diving petrels, general account, 771-773.
Dixon, C. C., 89.
Docas, isla de, 252.
Doce, rio, 160.
Doering, D. A., 188.
INDEX
Dogs, wild, at Falklands, 206; of Chilean desert,
265; at Galapagos, 301; as petrel enemies,
648.
Doldrums, 43, 44, 89, 106, 297.
Dolphin (Coryphaena), 78, 102, 164.
Dominica, 24, 25, 55.
Dofia Maria point, 272.
Double brood, of tropic-birds, 805.
Doucin, 135.
Douglas, G. V., 209.
Dovekie, 50.
Downy young, of three species of steamer
ducks, 954, 955.
Drake strait (or passage), 35, 92, 218.
Dreier, Dorothea, 34.
‘Dresden,’ 247.
Driftwood, in Caribbean, 115, 298.
Drilling (concerted movement), of penguins,
406.
Drinking habits, of sheath-bills, 1006.
Drowne, F. P., 6.
Du Petit Thouars, Abel, 97, 210, 267, 296.
Ducie I., 262.
Duck, blue mountain, 697.
muscovy, 137.
pintail, 252, 253.
Duncan I., 300.
Dungeness, point, 18.
Dunlop, Bruce, 28.
Durnford, Henry, 193, 194.
D'Urville, Dumont, 205.
Duststorms, 183, 271.
E
Eagle passage, 22.
Earle, Augustus, 217.
Earthquake, Chilean, of 1922, 259.
Earthquakes, in relation to tides and vibration-
waves, 273.
East Falkland, 22.
East I., 22.
East point, 169.
Easter I., 80, 94, 98, 263.
Echo-soundings, 218, 224.
Ecological, balance, upset by man, at Tristan
da Cunha, 616.
classification of sea birds, 326, 327.
relationships of penguins, 411.
Economic value, of penguins, 376, 413, 420,
421, 440, 452, 454; Bialbanteene 511, 512,
523, 535, 554, 556; of petrels, 653, 671,
674, 675, 685, 692, 695, 696, 707, 774, 777,
778, 779; of tropic-birds, 802; of pelicans,
821, 822; of cormorants, 877, 900; of man-
o'-war birds, 935; of gulls, 1084.
“Ecstatic attitude’ in intersexual behavior of
sea birds, 341, 392.
Ecuador and northern Peru, expedition to, 28.
Eder, P. J., 313, 316.
Edibility, of albatrosses, 551, 574; of steamer
ducks, 971; of oyster-catchers, 993; of
sheath-bills, 1003.
1219
Egg I. (Fernando Noronha), 146, 181.
Egging, at Falklands, 21, 376, 420, 441; at
Ascension, 153, 154, 1127; at San Ambrosio
I., 260; at South Georgia, 376, 430, 554,
556; at Deception I., 413; at Tristan group,
426, 427, 574; at Galapagos, 535; other
examples of, 260, 511, 523, 897, 902, 1068,
1085, 1097, 1120, 1127.
Egg-laying, latitudinal variation in, 557, 560.
Eggs, edibility of, of penguins, 21, 375, 420,
421, 426, 440, 441; of albatrosses, 512, 556,
557; of petrels, 617; of terns, 1097, 1116,
1120, 1127.
of three species of steamer ducks, 954, 972.
recognition of, by penguins, 375.
runt, 375, 413, 420.
sub-fossil, from guano beds, 291, 292, 453.
Egg-tooth, of penguins, 374, 379.
Eigenmann, C. H., 253.
Ekman, E. L., 24.
Elainea ridleyana, 148.
Elephant I., 218, 228.
Elimination of part of brood by boobies, 853,
857.
Ellsworth, Lincoln, 32.
El Muerto I., 29, 306, 307.
El Nifio current, 28, 101, 102, 103, 106, 108,
282, 284, 285, 294, 296, 297, 305, 318, 669,
740, 799, 840, 849, 903, 1073.
influence of, on terns, 1135, 1139.
El Rincén, 186, 189, 191.
El Roque I., 120.
El Yunque, 257.
Emerita analoga, 273, 275, 601, 609, 915, 981,
1052.
Empetrum rubrum, 205.
Beaten, in Humboldt current, 97, 99, 101;
at Galapagos Is., 101.
Enemies, of penguins, 354, 365, 385, 403, 414,
423, 424, 425, 431, 436, 447, 451, 454, 459,
470; of Procellariiformes, 480, 481; of alba-
trosses, 551, 555, 560, 564, 571, 574; of
petrels, 596, 616, 620, 624, 625, 627, 628,
631, 632, 681, 707; of storm petrels, 731,
746; of diving petrels, 777, 778, 789; of
tropic-birds, 802; of pelicans, 817, 818, 827;
of boobies, 832, 833, 834, 836, 837, 846,
853, 859; of cormorants, 891, 895, 898,
907; of kelp goose, 945; of steamer ducks,
963, 967; ohipscer atchone: 983; of sheath-
bills, 1003; of gulls, 1045, 1088; of terns,
1096, 1097, 1111, 1112, 1116, 1145.
Engraulidae, 1146.
Engraulis ringens, 98, 465, 826, 845, 878, 1056,
1136.
Enriching effect, of river waters upon sea, 138;
of islands, 158.
Ensenada de Samborombén, 185.
Environmental preferences, of oyster-catchers,
977, 980, 986, 991.
Epinephalus labriformis, 915.
Equatorial countercurrent, see El Nifo.
1220
Equatorial current, 86, 87.
‘Equatorial Strait,’’ of Atlantic, 89, 142.
Eragrostis peruviana, 260, 262.
‘Erebus,’ 193.
Ereunetes mauri, 275.
pusillus, 275.
Erga, punta, 119.
Erolia bairdii, 188.
fuscicollis, 188.
melanotos, 188.
Esmeraldas, 279, 309.
Espinillo, punta de, 184.
Espinosa, J. M., 299.
Espirito Santo, 144, 159, 172.
Essequibo, river, 126, 127, 129, 132.
Este, punta del, 169, 183.
Estero Elefantes, 245.
Eten, 9.
Eudyptes, 323, 334.
chrysolophus, 71, 222, 225, 227, 234, 386,
417, 419, 432.
crestatus, 74, 200, 208, 213, 383, 415, 435.
Eudyptula, 334.
Euphausia superba, 635, 1109.
Euphausians, 64, 70, 71, 92, 93.
Euxenura galeata, 187.
Evanjelistas Is., 237, 242.
Evolution, of Procellariiformes, 465, 476; of
whale-birds, 611, 614, 615; of diving
petrels, 772, 773; of Pelecaniformes, 793;
of three species of steamer ducks, 956, 957.
Evout I., 241.
Excrement, color of, in penguins, 378, 396.
Excretion, in birds, 338.
‘Exe, 22.
Experiments, in coloring eggs and feathers of
terns, 1130.
with noddy young and eggs, 1157.
‘Express,’ 24. |
ars eee of petrels, by man, 685, 696; of
iving petrels, 774; of Peruvian pelicans,
823; of South Georgian teal, 949; of oyster-
catchers, 976.
Extralimital records, of albatrosses, 510, 511,
523, 546, 575; of petrels, 603, 604, 650,
710, 711, 722, 733; of sooty tern, 1125,
1131, 1174.
Eye, relative large size of, in red-footed booby,
870.
Eye-color, dichromatism in, of giant fulmar,
587, 588.
Eyes, sexual dimorphism of, in blue-footed
booby, 834.
F
Fagnano, lake, 201.
Fairweather, cape, 17, 18.
Falkland, East, 203.
West, 203, 204.
Falkland current, 73, 82, 88, 93, 94, 206, 342,
543.
INDEX
Falkland Is., 8, 12, 20, 21, 37, 49, 69, 73, 76, 87,
88, 92, 93, 109, 169, 193, 197, 198, 200, 201,
203-208, 210, 213, 214, 219, 221, 222, 241,
249, 289; egging at, 21.
Falkland sound, 22, 203, 206.
False Cape Horn, 14,°16, 18, 241.
Fanning, Edmund, 204, 207.
Faraguet, C., 295. ;
Farmland, southernmost, 239; of Chiloé L,
248; of Mocha I., 251.
Fasting, of penguins during courtship, moult,
etc., 376, 378, 395, 401, 430; of young of
albatrosses, 561, 562, 581; of petrels, 593,
680, 790; of tropic-birds, 806.
Feather, use of in booby courtship, 835.
Feeding, of young, of penguins, 351, 378, 379,
380, 397, 450; of albatrosses, 560, 561; of
petrels, 593, 646, 676; of diving petrels,
790; of tropic-birds, 806; of pelicans, 815,
816, 826; of boobies, 837, 853, 858, 867; of
cormorants, 908; of skuas, 1019, 1027,
1030; of terns, 1129.
Feeding habits, specialized or aberrant, among
Procellariiformes, 486-489; of Wilson's
petrel, 232; of cape pigeon, 610; of whale-
birds, 636, 638; of guanay, 901, 905; of
phalaropes, 995; of noddies, sooty tern,
and fairy terns, 151, 1130, 1157, 1167; of
skimmers, 1176, 1177.
Feeding of mate, by penguins (snow only),
395; by tropic-birds, 805; by terns, 1097,
1128, 1129, 1156, 1158.
Feeding range, daily, of petrels, 660, 692; of
tropic-birds, 804; of boobies, 851, 859,
860, 869; of cormorants, 886, 893; of gulls,
1087.
Feet, function of in flight, of Procellariiformes,
485; of albatrosses, 565; as motive power,
of hydroplaning whale-birds, 621.
Felton, Mr., 22.
Females, exceeding males in size, among certain
storm petrels, 765, 766; among boobies and
man-o'-war birds, 795, 931; among phal-
aropes, 994.
Fernando Noronha, 25, 32, 47, 89, 130, 131, 133,
144, 146-149, 153, 155, 159, 168, 171, 298.
Fertilizing, by kelp gull, 1068.
Feruglio, Egidio, 194.
Field Museum of Natural History, 33.
Fighting, chiefly as phase of courtship or ter-
ritorial competition, 392, 393, 430, 445,
459, 553, 557, 945, 946, 962, 963, 966, 967,
1029, 1032, 1034, 1048, 1068.
Figueira I., 161.
Filchner, Wilhelm, 224.
Firewood, transportation of, from Beagle
Channel to eastern Patagonian coast, 16,
19.
Fish, predacious, followed by petrels, 751.
Fishing industry, at Abrolhos Is., 158; in south-
ern Chile, 245.
Fitchia, 260
INDEX
Fitz Roy, Robert, 40, 151, 196, 296.
Fitzroya patagonica, 247.
Flamingo, Andean, 275.
Chilean, 188.
West Indian, 165.
Flar I., 196.
Fleas, of penguins, 441, 461; of whale-birds,
628.
Flesh colors, change of, with physiological
rhythm of reproductive cycle, 381, 456,
550; sexual dimorphism in, 848, 849.
Flight, diversity of, in Procellariiformes, 483,
484, 485.
of guano birds, 270, 271; of condors and vul-
tures, 276; of Procellariiformes, 483-485; of
albatrosses, 507, 508, 509, 517, 532, 533, 540,
564, 565, 566, 567, 568, 569, 570, 574, 582;
of whale-birds, 618, 619, 622, 625, 629,
632, 633; of petrels, 593, 636, 640, 647, 652,
665, 672, 673, 699, 700; of storm petrels,
730, 731, 732, 735, 740, 742, 743, 744, 751;
of diving petrels, 780, 781, 791; of tropic-
birds, 800, 801; of pelicans, 816, 817, 824,
825; of boobies, 856, 869; of cormorants,
876, 886, 896, 901, 907; of man-o’-war
birds, 924, 930, 931; of steamer ducks, 969;
of oyster-catchers, 982, 984; of sheath-
bills, 1002; of skuas, 1025, 1028, 1030,
1031; of jaegers, 1039, 1040; of gulls, 1042,
1067, 1076, 1088; of terns, 1104, 1116,
1120, 1127, 1130, 1146, 1165, 1168, 1169;
of skimmers, 1175, 1176, 1177, 1178.
subsurface, of Procellariiformes, 486, 488,
672.
supreme, of sooty albatross, 495.
Flight distances, of albatrosses, 508, 546, 547,
561, 562, 574; of terns, 1101, 1102, 1143.
Flight-practice, of young, of albatrosses, 561,
562; of skuas, 1028.
Flightlessness, evolution of, 795, 870, 871; tem-
orary, in diving petrels, 777.
Flock formation, of petrels, 667, 668, 669, 675,
676, 679, 687, 689; of boobies, 839; of cor-
morants, 876, 894, 904, 906, 907; of South
Georgian teal, 948, 949; of steamer ducks,
962, 963, 967; of oyster-catchers, 978, 987,
988; of terns, 1111, 1113, 1146, 1157.
Flocking, as first stage of migration, 663.
Flood period, of Orinoco, 128; of Guiana
streams, 133, 134, 1173; of Peruvian rivers,
281; of the Paraguay-Parana, 181, 1173.
Floods, at St. Helena, 181.
river, in system of the Rio Loa, 265; correla-
tion with breeding season of skimmers,
1169, 1173.
Flores I., 255.
Florida caerulea, 166.
Flycatcher, vermilion, 307, 312.
Flying fish, 78, 81, 92, 102, 123, 151, 164, 285,
296, 304, 311, 851, 869, 1130, 1139; corre-
lation of, with distribution of certain
boobies, 829, 848, 849, 865.
1221
Fogs, on Caribbean coast, 117; in Sao Sebastiao
current, 161; on Argentine coast, 192; at
Gough I., 211; at South Shetlands, 229;
at Bouvet I., 233; at Mocha I., 252; along
desert west coast, 269, 270, 271, 273, 274,
277, 278.
Follicle-stimulating hormone, 341.
Food, of penguins, 353, 364, 377, 378, 397, 406,
414, 424, 437, 451, 460, 465; 470; of alba-
trosses, 497, 513, 514, 525, 530, 546, 562,
563, 581; of petrels, 594, 595, 609, 620, 624,
628, 633, 636, 637, 638, 640, 647, 653, 658,
660, 663, 666, 672, 681, 684, 689, 692, 708,
717, 718, 726; of storm petrels, 738, 743,
746, 754, 757, 759, 760, 767, 770; of diving
petrels, 776, 781, 786; of tropic-birds, 801,
806, 807; of pelicans, 826, 827; of boobies,
837, 845, 850, 851, 859, 861; of cormorants,
878, 882, 888, 891, 895, 915, 919; of man-
o'-war birds, 926, 936, 937; of ducks and
geese, 947, 951; of steamer ducks, 962, 968;
of oyster-catchers, 978, 980, 981, 982, 985,
993; of phalaropes, 997; of sheath-bills,
1006; of skuas, 1016, 1019, 1020, 1029,
1030; of gulls, 1045, 1046, 1048, 1055,
1056, 1063, 1069, 1070, 1074, 1076, 1081,
1086, 1088; of terns, 1089, 1093, 1094,
1097, 1109, 1113, 1116, 1118, 1130, 1132,
1135, 1136, 1140, 1144, 1146, 1148, 1157,
1158, 1160, 1163; of skimmers, 1175, 1176,
1177, 1178.
Food capacity, of penguins, 353; of cormorants,
873, 901; of skuas, 1032.
Foraminifera, of Brazil current, 87.
Forbes, H. O., 295.
Forbush, E. H., 52. .
Forests, destruction of, at Ascension, 154; nort
of Bahia, 157; at South Trinidad, 173; at
St. Helena, 179; at Juan Fernandez, 256.
Form and function, interdependence of, 476.
Formenkreis, of pan-antarctic cormorants, 323;
of petrels, 655, 697.
Forsyth, John, 34.
Fortaleza, 45, 140, 141, 143, 144.
‘Fortuna,’ 26.
Fossil flora of West Antarctica, 231.
Fox bay, 22.
**Fox,'’ Falkland, 206.
Franze, Bruno, 39, 40, 42, 116.
Fraser, F. C., 179.
Fray Juan I., 314.
Freezing of eggs, of black-bellied storm petrel,
766; of sheath-bill, 1004.
Fregata andrewsi, 924.
aquila, 80, 91, 149, 152, 153, 181, 920, 924.
ariel, 80, 91, 176.
ariel trinitatis, 921, 939.
magnificens, 80, 91, 101, 122, 146, 148, 149,
153, 165, 168, 176, 319, 322, 793, 1096.
magnificens lowei, 928.
magnificens magnificens, 920, 926, 928.
magnificens rothschildi, 124, 921, 927.
1222
minor, 80, 91, 101, 149, 176, 181.
minor januaria, 921, 939.
minor nicolli, 921, 938.
minor ridgwayi, 921, 937.
Fregatidae, 327, 919.
Fregetta grallaria, 74, 213, 218, 765.
grallaria grallaria, 258, 261, 262, 760.
grallaria tristanensis, 762.
leucogaster, 763.
melanogaster, 765.
tropica, 71, 222, 227, 764.
French antarctic expedition, 230, 231.
French peak, 16.
Frequency-distribution graphs, as means of
studying taxonomic relationships of skuas,
1008.
Fresh water, drinking of, by man-o’-war birds,
937; by steamer ducks, 961, 963; by oyster-
catchers, 978.
Freshwater bay, 298.
Frezier, A. F., 286, 287.
Frigate-bird, greater, 175.
lesser, 175, 176.
Frigate petrel, Galapagos, biography, 770-771.
Frio, cape, 41, 87, 89, 109, 144, 159, 161, 167,
200.
Fronton I., 277.
Froward, cape, 239.
Frozen’ attitude, of young terns, 1112, 1129;
of skimmers, 1178.
Frozen soil, as factor in distribution, of petrels,
643.
Fuchsia coccinea, 251.
Fulica armillata, 187.
leucoptera, 187.
rufifrons, 187.
Fulmar, antarctic, 72, 180.
Plant. 22.) 77, 22352255 231, 250) 2525 272.
401, 424, 555, 556, 558, 567, 609, 625, 628,
632; only terrestrial feeder, 482, 486; car-
nivorous habits of, 486; biography, 584-
596; attacking men in water, 564, 595.
silver-gray, 225, 243, 250, 272; biography,
596-601.
Fulmariprion, 613.
Furnarius, 281.
Fur seal, 14, 169, 179, 211, 222, 234, 241, 296.
G
Gabianus pacificus, 1040, 1044, 1060.
Gable L., 17, 19, 239.
Gain, Louis, 76, 230, 231, 233.
Gait, of penguins, 353, 359, 382, 383, 390, 414,
416, 450, 469; of albatrosses and petrels,
482, 483, 536, 537, 554, 565, 566, 568, 582,
594, 600, 609, 637, 646, 673, 680, 681, 707;
of storm petrels, 753, 759, 769; of diving
petrels, 778; of tropic-birds, 801, 805; of
cormorants, 905, 918; of oyster-catchers,
982, 984; of sheath-bills, 1003.
Galapagos expedition of the California Acad-
emy of Sciences, 5.
INDEX
Galapagos Is., 31, 32, 40, 44, 51, 81, 95, 97, 99,
100, 103, 108, 130, 148, 207, 257, 267, 268,
272, 282, 296, 303, 312, 314, 317, 342.
Galera I., 321.
Galera point, 250.
Gales, effect upon birds and destruction of bird
life by, 50, 51, 521, 593, 594, 648, 896, 1175.
Gallant, port, 242.
Gallegos, puerto, 191, 197.
Gallegos, rio, 190, 192, 199.
Gama, isla de la, 190.
Gamarra, Luis, 293.
Gambusia patruelis, 471.
Game birds, gulls as, 1084.
Garcilasso de la Vega, 286.
Garriott, E. B., 56.
Garrodia nereis, 21, 76, 208, 213, 222, 235, 746.
Garruma, 265.
Garta, 49, 263, 268.
Gastronomic classification of geese, 945, 946.
Geese and ducks, general account, 941.
Gelochelidon nilotica, 124, 137, 1042, 1092.
Generic names, advantage of comprehensive
use of, 325, 326.
Genetic basis, of booby distribution, 860; of
temperament of South Georgian teal, 949.
Georgetown, 44, 128, 129.
Geospizidae, 302, 317.
Gherritz, Dirk, 74.
Gibson, Ernest, 185.
Gilbert I., 243.
Gill, Geoffrey, 30.
Gill, Isobel S., 155.
Glaciation, at Falklands, 204; in Scotia arc
region, 218, 219, 224; at South Orkneys,
227; at Tierra del Fuego, 240, 243; at South
Georgia, 371; at Bouvet I., 417; at Heard
1. 417.
Glaciers, of Beagle channel, 16.
Goajira peninsula, 55, 113, 115, 117, 120, 144.
Goats, 118, 123, 173, 179, 217, 256, 257, 301,
307, 311, 312; destruction of forests by, 865.
Goeldi, E. A., 134.
Goetsch, Wilhelm, 256.
‘Golden Horn,’ 54.
Goleta I., 274.
Gonads, state of, as affecting migratory ac-
tivity, in shore birds, 275, 306; in sheath-
bills, 1003; in terns, 1139.
Gonzales I., 259, 261.
Good Hope, cape of, 214.
Good Success, bay and cape, 17, 19.
Goose, Falkland kelp, biography, 945-947.
kelp, 199, 241, 243, 246, 323; biography,
942-945; as food of Indians, 945.
Gordon I., 240.
Gorgona I., 315.
Gorgonilla, 315, 316.
Gough I., 32, 73, 75, 109, 171, 200, 203, 208-
214, 217, 218.
Grace, W. R., and Co., 27.
Graham Land, 218, 227, 229, 231.
INDEX
Gran Bajo Oriental, 195.
Grand I., 13.
Grande, Captain, 15, 16, 17.
Grande, ilha, 161.
Grande, rio, 163.
Grant; C. H. B., 153.
Grantham sound, 204.
Graves I., 243.
Graveyard, penguin, 372.
Grebe, pied-billed, 140.
red-breasted, 170.
Green mountain, 151, 152.
Grenada, 32, 114.
Grenadines, 123.
Grévy IL., 15, 241.
Grinnell, Joseph, 5, 6, 35, 276.
Ground-nesting, of brown pelican, 813, 814.
Growth, and rate of growth, in young, of
ppt, 398, 412, 436; of Procellarii-
ormes, 476, 479, 480; of cormorants, 891;
of gulls, 1065, 1066, 1067.
Guafo I., 246.
Guaitecas Is., 30, 246, 247.
Guamblin I., 246.
Guanaco, 19, 237, 240.
Guafiape Is., 96, 200, 289, 292.
Guanay, 274, 276, 277, 284, 290, 307; biogra-
phy, 899-909; 1145.
Guano, general account, 286-295; 121, 133,
147, 153, 190, 259, 262, 264, 265, 270, 277,
280, 285, 308, 453, 640, 774, 777, 778, 833,
836, 841, 842, 1126, 1145; enrichment of
food resources by, 93.
Guano Administration, see Compafiia Ad-
ministradora del Guano.
Guano birds, protection in Peru, 9; 98, 264, 281,
283, 284, 291, 293, 900.
“Guano glass,’’ at Caribbean islands, 124; at
St. Paul Rocks, 150; at Lobos de Tierra and
the Galapagos, 300.
Guara rubra, 166.
Guarira I., 158.
Guaruja, 167.
Guasco, river, 253, 263.
“Guayana,’ 24.
Guayaneco Is., 244.
Guayaquil, 28, 29, 268, 304, 305, 306, 308.
gulf of, 29, 30, 42, 49, 82, 96, 99, 103, 112,
137, 164, 275, 285, 303, 304, 305, 306, 307.
Guayas, river, 167, 305, 306, 307.
Gular sac, and its specialized function, in man-
: o'-war birds, 924, 931, 932.
Gulf stream,°82, 89.
Gull, Belcher’s, 272; biography, 1052-1057.
brown-hooded, 170; biography, 1082-1086;
1097.
4 Sige biography, 1043-1046.
dusky, biography, 1046-1049.
Franklin's, 272; biography, 1079-1081.
gray, 250, 272, 275, 291; biography, 1049-
1052.
gray-hooded, biography, 1074-1076.
1223
kelp, 10, 76, 109, 167, 188, 216, 225, 228, 247,
250, 281, 307, 636; as enemy of boobies,
836, 837; biography, 1057-1071; 1096,
1108, 1112.
laughing, 102, 140, 281, 284, 285, 305, 306;
biography, 1071-1074.
mountain, 99, 272; biography, 1077-1078.
Scoresby’s, 424.
spot-winged, 1116.
swallow-tailed, 99, 272, 317, 320; biography,
1086-1088.
Gulls and terns, general account, 1040-1043.
Gunnera peltata, 257.
Gygis, 1043.
alba, 80, 102, 148, 149, 152, 176, 181, 261,
263, 302.
alba alba, 1164.
alba candida, 319, 1168.
H
Habirat, classification of, of terns, 1042, 1043;
preferences of gulls, 1047, 1050, 1051, 1052,
1062, 1068, 1081.
Hacha, rio, 115.
Hacienda Grande, 15, 16.
Haematopodidae, 327, 973.
Haematopus ater, 74, 170, 200, 208, 252, 323,
975, 979, 980, 988.
leucopodus, 74, 199, 208, 323, 975, 979.
ostralegus, 323.
ostralegus durnfordi, 983.
ostralegus galapagensis, 981.
ostralegus ostralegus, 974.
ostralegus palliatus, 322, 975.
ostralegus pitanay, 252, 978, 991.
Hagmann, Gottfried, 136.
Hall I., 241.
Halley, Edmund, 173.
Hallinan, Thomas, 32.
Halobaena caerulea, 20, 74, 208, 232, 235, 611,
618, 630, 723.
Halobates, 771.
Halocyptena microsoma, 728, 729.
Hamlin, Hannibal, 6.
Harberton harbor, 19, 239.
Hardy, A. C., 60, 61, 63, 93.
Hardy peninsula, 14.
Harmattan, 117.
Harris, C. M., 4.
Hart, T. J., 65.
Hartert, Ernst, 35, 121, 235.
Harvey, H. W., 61, 62.
Harr, R. T., 179.
Hawk, duck, 307.
Hayes, A. A., 292.
Hazards, physical, in life of piquero, 845.
Hearst Land, 229.
Heilner, Van Campen, 28, 29, 30, 311.
Heilprin, Angelo, 126, 129, 134.
Heller, Edmund, 319.
Hellmayr, C. E., 35, 139, 244.
1224
Hemirhamphus, 137, 304, 1167.
Henderson I. (Fuegia), 14.
Henderson I. (Polynesia), 80.
Hen-feathering in male man-o’-war bird, 922,
924.
Hentschel, Ernst, 65, 71, 74, 76, 77, 78, 81, 85,
86, 89, 91, 93, 137, 168, 178, 234.
Herald point, 214.
Hermite I., 15, 241.
Heron, cocoi, 128, 312.
great blue, 302.
Herschel I., 15, 241.
Heteronetta atricapilla, 187.
Heteroscelus incanus, 309.
Hill-climbing, of penguins, 370, 371, 398, 413
431, 463.
Hilly point, 196.
Himantopus himantopus melanurus, 187.
Hippoboscid flies, on boobies, 850.
Hoatzin, 132.
Hogs, at South Trinidad, 173; at Inaccessible,
217, 301; at Tristan da Cunha, 426, 617;
as petrel enemies, 648.
Holdfast Tom, 180.
Holmes, F. H., 3.
Holtedahl, Olaf, 218.
Homing, of penguins, 385, 390, 430; of shear-
waters, 679; of noddies, 1154, 1155.
Homing experiments, with terns, 1131, 1155.
Honeymoon trip of petrels, after preparation of
nests, 676.
Hood I., 300, 303.
Hooker, Joseph, 178, 179, 193.
Hopping, of penguins, 416, 436.
Hormigas de Afuera Is., 10, 32, 276, 277, 715,
732, 739, 740, 742, 759, 840.
Hormones, place of, in penguin behavior, 341.
Horn I., 241.
Horses, at Falklatids, 206; at South Georgia,
222; at Galapagos, 301.
Hoste 1., 13, 14, 241.
Hotspur bank, 144.
Hudson, W. H., 183.
Huemules, rio, 246.
Huigra, 304.
Humboldt, Alexander von, 117, 119, 123, 126,
164, 286.
Humboldt bay, 316.
Humboldt current, 10, 28, 40, 49, 61, 66, 73,
75, 81, 82, 87, 94-98, 103, 106, 108, 144,
161, 164, 169, 198, 255, 263, 264, 267, 269,
270, 274, 276, 278, 280, 282, 283, 289, 295,
296, 297, 303, 304, 305, 342, 461, 467, 509,
669, 799, 820, 849, 900, 1131, 1140, 1144,
1149; avifauna of, 9, 99-101; shore fishes
of, 98; effect of, on tern distribution, 1131,
1140, 1144, 1149.
Humid zone of high islands, as petrel breeding
grounds, 699.
Humidity, as correlated with booby distribu-
tion, 855, 860.
NED EEX
Hunger, as the stimulus behind the exodus of
fledglings from the nest, 680, 807, 1144.
Hurricanes, in relation to birds, 51-59; effect
upon sea fowl of various groups, 117, 664,
711, 733, 734, 817, 930, 931; forecasting of,
by man-o'-war birds and terns, 55, 56, 1131.
Hurricane waves, 55, 155.
Hutchinson, T. J., 289, 292.
Hyacinth, water, 305.
Hybridization of shags, 892.
Hyde, Mt., 241.
Hydranassa tricolor, 166.
Hydrobates pelagicus, 732.
Hydrobatinae, 726, 728.
Hydrometridae, 1088. °
Hydroplaning, so-called, a specialized style of
flight of certain petrels, 485, 488, 607, 621.
Hydrurga leptonyx, 179, 354.
Hymenocallis, 311, 850.
I
Ibiapaba mountains, 140.
Ibis, scarlet, 120, 127.
Ica, rio, 272, 274.
Ice conditions at sea, foretold by presence of
certain birds, 635, 639.
Icebergs, of great size, near South Sandwich Is.,
224.
Iceberg riding (ice-ferrying), of penguins, 409,
410; of sheath-bills, 1002.
Igapds, 139.
Igarapés, 137.
Iguapé, 162, 168.
Ihering, Hermann von, 167, 168.
Ihering, Rodolpho von, 167, 168.
Ildefonso I., 13, 14, 201, 420, 515.
Ilheos, 157.
Immunity of certain small species from attacks
of skua, 1031.
Inaccessible I., 216, 217.
Imani I., 96.
Incas, bird protection by, 822, 823.
Incubation, alternation of sexes in, among
petrels, 672, 680, 692; preponderant share
of male in, among storm petrels, 737.
Incubation period, of penguins, 350, 361, 374,
423, 430, 431, 435, 445, 449, 459; of Pro-
cellariiformes, 478; of albatrosses, 504, 555,
556, 558, 560; of petrels, 605, 676, 680; of
storm petrels, 732; of diving petrels, 790;
of tropic-birds, 806; of boobies, 829; of
oyster-catchers, 978; of sheath-bills, 1004;
of skuas, 1022; of gulls, 1068, 1074; of
terns, 1118, 1126, 1129, 1156.
Indefatigable I., 32, 298, 300, 301.
Independencia bay, 27, 263, 272, 273. \
Indians, Yahgan, 15; Peruvian, 286; prehistoric,
on Chincha Is., 292.
Individuality (of responses), among penguins,
394, 404, 412.
of voice, as recognition mark of petrels, 679.
INDEX
Infantilism, permanent, in incapacitated Pele-
caniformes, 795, 796.
Infertility of booby eggs, 857.
Inhibition of digestion in birds, 660.
Injuries to gulls, 1049, 1052.
Injury-feigning reaction, and its significance,
950, 1178.
Inland range, of certain gulls, 1061, 1062, 1084.
Inshore birds, defined, 326.
Intelligence, lack of, among penguins, petrels,
and Pelecaniformes, 363, 364, 396, 397,
401, 406, 592, 815, 816, 824, 835.
Intergradation, among races of oyster-catchers,
SVAAEVER
International Petroleum Company, 284.
Interspecific associations, of penguins, 386,
389, 413, 425, 426, 427, 434, 435, 441, 442,
463, 465, 468, 470; of Procellariiformes,
426, 476, 478, 489; of albatrosses, 426, 512,
513) SU7, 520) 521, 529: 530; 5365/552,0555;,
555, 556, 558; of a southern-hemisphere
albatross with northern gannets, 511; of
petrels, 624, 627, 636, 637, 647, 649, 650,
662; of storm petrels, 732; of diving petrels,
776, 786; of pelicans, 817, 818; of boobies,
841, 842, 843, 844, 845, 866; of cormorants,
890, 893, 907, 908, 914, 915; of man-o'-
war Girls. 933, 934, 937; of steamer ducks,
966; of oyster-catchers, 977, 980, 982, 988,
992; of phalaropes, 997; of sheath-bills,
1003, 1005; of skuas, 1022, 1023; of gulls,
1045, 1046, 1049, 1051, 1069, 1072, 1076,
1080, 1085; of terns, 1091, 1093, 1096, 1097,
1103, 1108, 1109, 1112, 1113, 1115, 1116,
1118, 1128, 1130, 1132, 1139, 1140, 1144,
1145, 1153, 1158, 1159, 1163, 1165, 1166;
of skimmers, 1175.
Intestines, of penguins, 437.
Invierno Cinverno), 40, 41, 140, 281, 306, 309.
Iquique, 10, 96, 263, 286.
Iquitos, 38.
Iracoubo, river, 133.
Isanomalous lines, 297.
Isidro, point, 12, 13.
Islay Is., 96.
Italia glacier, 240.
Itamaraca I., 156.
Ixobrychus involucris, 187.
J
Jabiru, 132, 137.
Jacuhy, rio, 163.
Jaeger, long-tailed, biography, 1038-1040; 1116.
parasitic, biography, 1037-1038; 1097, 1116.
pomarine, biography, 1035-1036.
Jaegers, general account, 1034-1035; 1096, 1104.
Jaguaribe, river, 139.
Jambeli I., 30, 306.
James I., 32, 298, 300.
Jamestown, 155, 181.
Jangada, 142.
Janssen bay, 193.
1225
Jaques, F. L., visits to Peru and elsewhere, 27,
31, 32; paintings by, 34; 261.
Jason Is., 20, 206.
Jatropha gossypifolia, 147.
Jefferson, Mark, 96, 268.
Jellyfish, 274, 283.
Jequetepeque, rio, 280.
Jerdan [., 241.
Jervis I., 300.
Jespersen, P., 65, 90, 91.
Joazeiro, 140.
“Job of the North,’’ 46, 140.
John, D. D., 69, 71, 227.
Johns, Kathryn, 34.
Johnson harbor, 21.
Johnston, I. M., 259, 260, 277.
Joinville I., 219.
Jones, F. W., 39.
Joubin, Louis, 144.
Joy-riding, of penguins, 399.
Juan, George, 286.
Juan Fernandez Is., 8, 11, 31, 46, 66, 75, 79, 94,
254-258, 260, 263, 272.
Juania, 257.
Juania australis, 256.
‘Julia,’ 217.
Jumping, of penguins (ashore), 390, 416, 436,
465; of flightless cormorant, 918.
Junin, lake, 9, 110.
Juvenile life, length of, of king penguin, 351;
of emperor penguin, 362; of gentoo pen-
guin, 377.
K
Keeler, C. A., 3.
Kelp, giant, 89, 165, 192, 193, 206, 211, 216,
221, 224, 276, 347, 421, 451.
Kemp, Stanley, 224, 225.
Kerguelen I., 154, 193, 222.
Kerhallet, C. P. de, 94.
Kermadec Is., 79, 80.
Kidney I., 21, 22.
Kidney, of birds, 337.
Killing of young, by pelicans, 816.
King I., 13.
Kinnear, N. B., 154.
Knight, E. F., 174.
Koenigswald, Gustav, 162.
SKelleeiile
L
La Guaira, 116, 118, 123.
Lagunillos, 116.
Lagunularia, 132.
Lambrecht, Kalman, 180, 266, 295.
Lamellae, of whale-birds, 614, 615, 619.
Land-bridge hypotheses, 148, 734.
Landfall I., 243.
Landing, of albatrosses, 566.
Landslides, 307; destruction of boobies by, 831.
Lantana, 118.
La Plata, gulf of, 181, 200.
La Plata I., 29, 30, 81, 285, 309, 311, 312, 315.
1226
Laridae, 327, 1040.
Larinae, 1040.
Larosterna inca, 100, 277, 323, 463, 1042, 1143.
Lars I., 234.
Larsen, C. A., 26, 223, 225.
Larus atricilla, 102, 122, 124, 312, 1071.
belcheri, 100, 323, 827, 1040, 1052, 1080.
cirrocephalus, 187, 1041.
cirrocephalus cirrocephalus, 1074, 1083.
crassirostris, 1040, 1054.
dominicanus, 76, 109, 167, 168, 170, 187, 189,
ZOU; 208; | 2135 2225 225) 227, 232, 952) 253,
277, 312, 323, 827, 992, 1040, 1045, 1055,
1057, 1109.
dominicanus austrinus, 76.
fuliginosus, 101, 1040, 1046.
fuscus, 1059.
glaucodes, 1083.
heermanni, 1040, 1045.
maculipennis, 170, 183, 187, 189, 208, 2535
1041, 1075, 1076, 1082, 1115.
marinus, 1059.
modestus, 100, 250, 980, 1040, 1049, 1054,
1080, 1081.
pipixcan, 99, 1079.
ridibundus, 1041, 1084.
serranus, 99, 1077.
Las Pefias, 305.
Launching into flight, difficulties of, among
Procellariiformes, 487, 529, 582; among
tropic-birds, 801.
Laurelia aromatica, 251.
Laurie I., 225, 226.
Lavalle, J. A. de, 293.
Lavandeira coral reef, 140.
Lavarié, punta, 252.
Lavatera plebeja, 632.
Layard, E. L., 90.
Leaping ability, of penguins (in water), 384;
on land, 422.
Learning ability, of penguins, 372, 378, 405,
464, 471; of terns, 1129.
Lee shores, in relation to birds, 50, 51.
Leguri, 12, 13, 15; 16.
Le Maire, strait of, 198, 234.
LengGes Grandes and Pequenos, 139.
Lengua de Vaca, peninsula of, 254.
Leones Is., 194.
Leskov I., 224, 225.
Leucophaeus scoresbii, 74, 199, 208, 252, 323,
1040, 1043, 1054.
Leucophoyx thula, 166.
Lianas, 134, 137, 244; lacking at Juan Fernan-
dez, 256.
Life zones, determined by surface water, 59;
general description of, 65-81; uniformity of
pan-tropical, 79; relative abundance of
birds in, 90.
Light, inhibiting effect of, upon incipience of
breeding in petrels, 679; attracting or con-
fusing effect of (including firelight), 617,
652, 679, 726, 729, 748, 775, 785, 789.
INDEX
Light, William, 29.
Lighthouses, destruction of petrels by, 672.
Lightning, causing combination of nitrogen
and oxygen in atmosphere, 78; on Peruvian
coast, 304.
Lima, 9, 28, 96, 264, 268, 295.
Limari, rio, 252, 254, 263.
Limicolae, 113, 165, 306, 314.
Limpkin, 137.
Lindbridge, Captain, 4.
Little Saba I., 23, 24.
Littoral birds, defined, 326.
Lizards, 280, 285, 307, 315, 319, 320.
Llahuen I., 247.
Llanquihue, lake, 249.
Lluta, river, 264.
Loa, rio, 38, 253, 264, 265.
Loberos, punta de los, 169.
Lobipes lobatus, 997.
Lobitos, 285.
Lobos, banco, 190.
Lobos Is. (Brazil), 169, 184.
Lobos Is. (Peru), 100, 103, 109, 300.
Lobos Is. (Uruguay), 169, 170.
Lobos, punta, 190.
Lobos de Afuera I., 96, 280.
Lobos de Tierra I.,'27, 96, 109, 124, 144, 202,
277, 278, 280, 288, 292, 315.
Lobsters, at Juan Fernandez, 254; at San Felix
I., 259, 260.
Locality, as the important factor in the recog-
nition of nests by birds, 1130, 1157.
Locumba valley, 286.
Loeb, Jacques, 64.
Loma formation, 277.
Lomaria Boryana, 211.
London I., 13.
Londonderry I., 16.
Long Reach, 242.
Longevity, of Pelecaniformes, 795; of gulls,
1057, 1069; of terns, 1143.
temperature coefficient of, 64.
Longwood, 180.
Lénnberg, Einar, 35, 257.
Loomelania melania, 99, 314, 726, 740, 743.
Loomis, L. M., 4, 5, 6.
Lophortyx californica, 257.
Lord Howe I., 79, 80.
Lort bay, 14, 17.
Los Hermanos Is., 122.
Loss of function, in flightless cormorant,
917.
Lota, 252, 253.
Lot’s Wife, 181, 209.
Louis, port, 21.
Lowe, P. R., 10, 35, 118, 122, .123,,2135
Loyola, point, 18.
Luederwalt, Hermann, 167, 168.
Lycodes, 193.
Lyon, M. W., Jr., 118.
INDEX
M
Macabi Is., 289.
Macareo, mouth of Orinoco, 127.
Maceid, 157.
MacFarlane, J. R. H., 263.
Machalilla, 309.
Mackaye, James, 52, 55.
Mackintosh, N. A., 68, 70.
Mackworth-Praed, C. W., 153.
Macquarie I., 67.
Macrocystis pyrifera, 165, 192, 193, 221, 451.
Macronectes giganteus, 76, 99, 102, 188, 213,
218, 222, 225, 227, 232, 235, 258, 584.
Macrura, 628.
Macuto, 118.
Madeira, 80, 90, 159, 179, 208, 255.
Madryn, puerto, 194.
Magallanes (Punta Arenas), 11, 12, 13, 14, 16,
18, 21, 30, 239, 245, 250.
Magdalena, river, 37, 113, 114, 115, 120.
Magellan, strait of, 12, 13, 20, 30, 37, 38, 49,
50, 69, 190, 191, 192, 197, 198, 203, 238,
239, 240, 242, 243, 248; number of ex-
peditions to, 237.
Malaspina, Commodore, 319.
Maldonado, department of, 169, 184.
Malinka, 30
Mallophaga, of albatrosses, 571; of pelicans,
818, 827; of cormorants, 907.
Malpelo I., 44, 102, 108, 302, 317, 319-320.
Malpelo point, 303.
Malthusian relationship between food supply
and size of brood, of boobies, 844.
Manabi, 305, 309.
Manatees, alleged presence of, at St. Helena,
179.
Mancora valley, 285.
*“*Manglares,"’ 306.
Mangroves, 112, 114, 118, 119, 120, 1225) 129,
130, 131, 132, 134, 138, 139, 141, 157, 296,
301, 303, 305, 306, 314, 316, 317; growth of,
and effect in building land, 125, 126; ec-
ology, 126; southern limit of, 163; on east
coast of South America, 164, 166.
Maniguarez, 123.
Mann, Albert, 97.
Mann, Alexander, 300.
Man-o'-war bird, Ascension, biography, 924-
926.
Caribbean, biography, 927-937; 1155.
Galapagos, biography, 926-927.
lesser, biography, 939-940.
magnificent, 58.
Ridgway’s, biography, 937-938.
South Trinidad, biography, 938-939.
Man-o'-war birds, general account, 919-924;
not pelagic, 91, 793, 919, 920; as message-
carriers, 935.
Man-of-War Roost, St. Helena, 181.
*Mantalite,’ 29.
Mantas, leaping, 304.
1227
Manure, of birds, effect of upon vegetation,
373, 374.
Maorioris, use of shearwaters by, 671.
Maoris, use of petrels by, 648, 671, 692.
Maqui, 251, 256, 257.
Mar, ilha do, 161.
Mar, serra do, 162.
Mar del Plata, collecting at, 12; 186-189.
Maraca I., 135.
Maracaibo, gulf of, 42.
Maracaibo, lake, 42, 114, 116, 120.
Marajo I., 136, 137, 138.
Maranhdo, 141, 144, 156.
Marasmius, 221.
Mareca sibilatrix, 187, 202.
Margarita I., 113, 116, 121, 122, 123.
Marryat, Frederick, 173.
Martin Garcia I., 185.
Martin Vas Is., 79, 144, 171-176.
Martinique, 24, 25.
Martius, C. F. P. von, 167.
Marvin, C. F., 53.
Mas Afuera I., 11, 31, 98, 254, 255, 256, 257,
258, 262.
Mas Atierra I., 11, 31, 98, 254, 255, 256, 257,
258, 262.
Mass emigration, of cormorants, 903, 904.
Mate, retention of same, during successive
years, 890; retention of for life, 679, 960.
Mathews, Gregory, 154, 217, 218.
Mating behavior, in penguins, 393, 411; in
albatrosses, 513, 529, 535, 536, 551, 552,
553, 554, 555, 557; in petrels, 590, 591, 599,
644, 645; in cormorants, 887; in terns,
1155; continuance of by albatrosses after
hatching of eggs, 557, 558.
Matthews, L. H., 73, 74.
Matuna, boca de, 114.
Maull, Otto, 141.
Maullin, rio, 249.
Mazorca I., 10.
McAtee, W. L., 275.
McBride, G. McC., 297.
McCormick, Robert, 173.
Mecking, Ludwig, 221, 222, 225, 226.
Mediterranean zone, 46, 65.
Megadyptes, 334.
Megalopterus, 1149.
Mejillones, 265, 267.
Melanodera, 213.
Meliss, J. C., 178, 180, 181.
Mentor current, 84, 94, 255.
Menzies, Ida (Mrs. R. H. Beck), 5.
Merriman, C. S., 289.
Mesembrinibis cayennensis, 166.
Mesembryanthemum, 632.
Messier channel, 30, 243.
‘Meteor,’ 65, 76, 77, 81, 87, 89, 93, 137, 150,
151, 158, 168, 178, 181, 191, 224, 229, 233,
234.
Meteorological equator, 52, 106.
Metopiana peposaca, 187.
1228
Mexiana I., 136, 137.
Meyer, H. H. F., 83, 85.
Mice, at Gough I., 211; as petrel enemies, 746.
Michler, Nathaniel, 112, 316.
Micranoiis, 1149.
Migration, of penguins, 338, 362, 369, 390, 391,
394, 395, 403, 411, 422, 427, 431, 435, 436,
445, 450, 451, 456; of albatrosses, 534, 551,
552, 556, 560, 561, 574, 582; of petrels, 593,
604, 617, 626, 627, 631, 635, 636, 644, 659,
674, 678, 706, 708, 716, 724; of storm
petrels, 726, 728, 750, 751, 752; of diving
petrels, 772; of tropic-birds, 803, 805; of
boobies, 857; of cormorants, 889, 890; of
geese and ducks, 941; of oyster-catchers,
979, 987; of phalaropes, 993, 996, 999; of
sheath-bills, 1002; of skuas, 1007, 1008,
1017, 1019, 1022, 1026, 1028, 1033; of
jaegers, 1034, 1035, 1036, 1037, 1039; of
gulls, 1072, 1073, 1078, 1080, 1085, 1097;
of terns, 1043, 1089, 1101, 1104, 1105, 1108,
1109, 1114, 1125, 1127, 1139, 1144, 1149,
1151, 1152, 1154, 1155, 1157, 1166; of
skimmers, 1172, 1174.
Migration, as correlated with latitude of nest-
ing ground, of gulls, 1064, 1065.
extent of, among various zonal sea birds, 79.
length of, as correlated with length of re-
productive period of sub-antarctic petrels,
672.
nutritional stimulus of, in petrels, 681.
transequatorial, of northern petrels, 736.
Migration rout®, regular geographic course of
in North Atlantic, as followed by three
species of southern-hemisphere petrels,
661, 662, 751.
Millionth map of Hispanic America, 300.
Mirage, 118, 185; at Chiloé I., 249.
Miritiba, 139.
Mirounga, 169.
Misidentification, in field or in literature, of
penguins, 409, 417, 433, 461; of albatrosses,
579; of petrels, 610, 746; of gulls, 1054,
1075, 1083; of terns, 1095, 1101, 1103, 1105,
1106, 1107, 1109, 1151, 1153, 1162.
Mitchell, C. L., 56.
Mocha I., 32, 75, 95, 96, 199, 201, 250, 251,
252, 263.
Mollendo, 10, 28, 96, 272, 273, 283, 285.
Mollusks, as clues to the geologic age of strata
on Patagonian coast, 194.
Mollymauk, black-browed, 565.
Mollymauks, 491; origin of name, 507.
Monachus, 169.
Mondongos, 137.
Mongoose, 694, 697.
Monjes Is., 124.
‘Monongahela,’ 422.
Monos I., 113.
Monsoon, 46, 314; in northeastern Brazil, 141.
Montagu I., 224.
Montecriste, 311.
INDEX
Montevideo, 12, 23, 184, 254.
Monument peak, 212.
Moonlight, inhibiting effect of, on nocturnal
activities of petrels, 679.
Morong, Thomas, 184.
Morphological relationships, of Spheniscus,
442, 443; among albatrosses, 553; of diving
petrels, 771; of Pelecaniformes, 794.
Morrell, Benjamin, 223, 260, 288.
Mortality, of young emperor penguins, 360,
361; of penguins, 389, 440, 447, 451; of
albatrosses, 551, 574; of petrels, 616, 620,
624, 625, 627, 628, 631, 632, 676; of storm
petrels, 753, 766; of pelicans, 818; of
boobies, 835, 836; of steamer ducks, 963,
967; of skuas, 1019; of terns, 1129, 1148; of
skimmers, 1177.
Mortality, prenatal, of boobies, 857, 858, 866;
of terns, 1127.
Mortenson, T., 179.
Morton I., 14, 243.
Morus bassana, 829.
Mosby, Haakon, 234.
Moseley, H. N., 86, 148, 150, 151, 216, 217.
Moses, Alan, 173.
Mosquitoes, as enemies of pelicans, 818.
Mosquito bank, 37.
Moult, of penguins, 351, 352, 363, 365, 376,
379, 380, 402, 403, 404, 413, 424, 431, 436,
437, 442, 450, 456, 459, 460, 464, 465, 471;
of Procellariiformes, 482, 483; of alba-
trosses, 549; of petrels, 600, 605, 655, 662,
665, 669, 677, 681, 716, 721; of storm
petrels, 730, 732, 736, 742, 757, 759; of
diving petrels, 777, 782, 783, 789, 790; of
tropic-birds, 796; of boobies, 833; of cor-
morants, 884, 885, 893, 899, 911; of kelp
goose, 944; of steamer ducks, 961, 971; of
skuas, 1015; of jaegers, 1039; of gulls, 1054,
1080, 1084; of terns, 1099, 1109.
Moult, complete pre-nuptial moult of Frank-
lin’s gull, 1080.
double, its possible significance, 1080.
Mountain-nesting, of Hornby’s petrel, 742.
Mouth-structure, of cape pigeon, 610; of whale-
birds, 610, 614, 615, 619, 624.
Mud, incompatibility of, with growth of
corals, 144.
Mudbanks, off Orinoco, 128; evanescent char-
acter of, on coast of Guiana, 129, 132, 134;
off Amazon, 135.
Mud flats of river Guayas, 306.
Muddy water, as factor in limiting coastal
range of brown pelican, 130, 131.
Muerta, isla, 252.
Miller, Lorenz, 136, 137.
Multiple parenthood, of emperor penguin, 361,
362.
Mummies, of birds in Chilean saltpeter fields,
264; of petrels, 265, 671, 743; of cormorants
in nitrogenous guano from Tarapaca, 266;
of penguin, at Huanillos, Chile, 266.
INDEX
Mundy, Peter, 154, 179.
Munida, 73, 74, 98, 609, 610, 776.
Murphy, R. C., 6, 50, 86, 96, 97, 98, 148, 172,
197, 222, 270, 273, 274, 275, 276, 278, 280,
281, 283, 284, 285, 289, 294, 295, 303, 304,
305, 306, 308, 309, 311, 316; work at South
Georgia, 25, 26; in Peru, 27; in Ecuador
and northern Peru, 28, 29.
Murphy, Mrs. R. C., 29, 34.
Murray narrows, 15, 16, 18.
Museum of Comparative Zodlogy, 33.
Museum of Vertebrate Zodlogy, 33.
Mutation, as source of breeding behavior, 457,
458; among man-o'-war birds, 922; in
oyster-catchers, 973.
Mutton bird, 674, 703.
Mutual recognition between parents and young,
of terns, 1129.
Mutually exclusive nesting territories of diving
petrels, 789.
Mycteria americana, 166.
Myopism, of penguins, 338, 374, 382.
N
Nacella fuegiensis, 963.
Nannopterum harrisi, 101, 302, 870, 916.
Najfos, I., 243.
Narborough, Sir J., 242, 296, 300.
Nassau bay, 15, 241.
Natal, 47.
Natales, puerto, 31.
Navarino I., 15, 18, 239, 240.
Navassa I., 24.
Naya, rio, 314, 315.
Negro, river, 189, 190, 192, 289.
Nelson, A. L., 225.
Nelson, George, 224.
Nematistius, 311.
Nesocichla, 217.
Nesomimus, 302.
Nesopelia, 302.
Nesospiza wilkinsi, 217.
Nesotriccus ridgwayi, 317.
Nest-building habits and régime, of penguins,
373, 374, 393, 412, 422, 423, 426, 428, 429,
440, 442, 446, 447, 448, 459; of albatrosses,
426, 492, 497, 503, 512, 513, 517, 518, 523,
526, 528, 553, 554, 555, 562, 573, 574, 581;
of petrels, 591, 605, 616, 617, 620, 626,
627, 631, 632, 633, 635, 636, 637, 640, 645,
653, 680, 706, 707, 708, 733; of storm
etrels, 737, 746; of pelicans, 825; of
oobies, 841, 842, 857, 861, 866; of cor-
morants, 875, 876, 877, 886, 887, 889, 890,
894, 898, 914, 915, 918; of man-o’-war
birds, 931, 935; of steamer ducks, 967;
of oyster-catchers, 977, 980, 984, 988, 992;
of sheath-bills, 1004; of skuas, 1019, 1022,
1026; of gulls, 1045, 1054, 1063, 1067, 1068,
1073, 1074, 1085; of terns, 1089, 1091, 1108,
1109, 1111, 1115, 1118, 1119, 1120, 1128,
1229
1135, 1145, 1149, 1151, 1153, 1154, 1155,
1156, 1159, 1161, 1162, 1164; of skimmers,
ISS ALT.
Nest material, methods of obtaining, by man-
o’-war birds, 931, 932.
Nesting site, occupation of same, during suc-
cessive years, by petrels, 671; by boobies,
866.
variability of, according to environmental
factors, 445, 446, 447, 449, 462, 463, 685,
691, 719; 721, 766, 932, 1111, 1120, 1135,
1136, 1154, 1159, 1161, 1166, 1167, 1169.
Nestling life, length and régime of, in penguins,
449; in various Procellariiformes, 483, 732;
in Pelecaniformes, 806, 858, 894.
Nests, occupation of, as places of rest, outside
the breeding season, by albatrosses, 518,
523; by petrels, 617, 663, 713; by storm
petrels, 730.
New I., 19, 22, 289.
Newton, E. T., 265.
Nichols, J. T., 98.
Nicoll, M. J., 151, 176, 242.
Nidification, of Procellariiformes, 476-480.
Niehorster, Charles, 8.
Nightingale I., 208, 216, 217.
Nihue, punta de, 250.
Nifio years, 103.
Nitrate deposits, and their origin, 265, 266, 267.
Noco, pampas de, 274.
Nocturnal predilections, of Procellariiformes,
481, 486, 646, 652, 687, 699, 712, 725, 728;
of certain boobies, 858, 869, 870; of noddies,
1154; of skimmers, 1175, 1177; skua as a
selective factor in, of petrels, 785.
Nocturnal régime, of petrel calls at nesting
colony, 676, 679; of fledgling shearwaters,
680.
Nocturnal visits to burrows, in advance of
nesting season, of petrels, 679.
Noddy, Atlantic black, biography, 1160-1163.
black, 151, 153, 176, 1150, 1151.
brown, 123, 147, 153, 261, 1125, 1149; biog-
raphy, 1150-1158; 1161, 1162, 1163.
Cocos black, biography, 1163-1164.
Galapagos, biography, 1159-1160.
gray, 79.
San Felix, biography, 1160.
Socorro, biography, 1158-1159.
Noddy terns, general account, 1149.
Noir I., 243.
Non-breeding migrants in South America
during northern summer, 30.
‘“‘Norte,"’ 48.
North, cape, 135.
Norton, E. H., 29, 306.
“‘Norvegia’ expedition, 234.
Nothofagus antarctica, 238.
betuloides, 238, 244.
dombeyi, 247.
pumilio, 238.
Notothenia macrocephala, 1113.
1230
Noriopsylla kerguelenensis, 628.
‘Nourmahal,’ 31.
Nova Zembla I., 293.
Nuevo, gulf, 190, 194.
Numenius borealis, 186, 187.
hudsonicus, 275.
Nurseries, penguin, 379, 380, 398.
Nutrition, basis of marine, 61-64; closed cir-
cuit of, in sea, 62, 901.
Nyctanassa violacea, 166.
Nycticorax nycticorax, 202.
nycticorax hoactli, 187.
Nycticryphes semi-collaris, 187.
Nyroca erythrophthalma, 142.
Oo
Ober, F. A., 55.
Oberholser, H. C., 35.
O'Brien I., 16.
Ocean currents, 39, 40, 81-108, 237; direction
and planes of movement, 84, 85.
Oceanic climate, 69.
Oceanic influences, in relation to range of alba-
trosses, 534, 535; inhibiting pelican dis-
tribution, 811.
Oceanic islands, enriching effect of, upon sea
water, 86, 92.
Oceanites gracilis, 728.
gracilis galapagoensis, 101, 759.
gracilis gracilis, 100, 264, 757.
gracilis kelsalli, 10.
oceanicus, 71, 99, 158, 168, 189, 201, 213, 222,
225, 227, 232, 258, 728, 745.
oceanicus chilensis, 754.
Oceanicus Oceanicus, 748.
Oceanodroma castro, 80, 101, 153, 175, 180, 728.
castro bangsi, 734.
castro castro, 732.
furcata, 728.
homochroa, 728.
hornbyi, 100, 264, 277, 728, 741, 745.
leucorhoa, 124, 745.
leucorhoa leucorhoa, 734.
macrodactyla, 728, 745.
markhami, 100, 265, 277, 728, 739, 745.
tethys, 728, 758.
tethys kelsalli, 100, 277.
tethys tethys, 101, 272, 729.
tristrami, 740, 746.
Ocofia, 272.
O'Connell, Geoffrey, 30.
Odor of colonies, of penguins, 396, 429, 433,
436; of petrels, 676, 738; of cormorants,
894; of terns, 1126.
of Macaroni penguin, 433; of sheath-bills,
1006.
Offshore birds, defined, 326.
Ofqui, isthmus of, 245.
Ogilvie-Grant, W. R., 154.
‘Ohio,’ 282.
Oil, penguin, traffic in, 346; 452.
Olinda, 142.
INDEX
Ombi, 185.
Open season, legal, on petrels, in Tasmania, 675.
Opisthocomus hoazin, 132.
Opossum-shrimps, see Euphausian.
Optimum climate, of terns, 1043.
Oreodoxa oleracea, 130.
regia, 130.
Oreophilus ruficollis, 202, 973.
Organ mountains, 160.
Organos, cerro de los, 303.
Origin, terrestrial, of all groups of warm-
blooded animals, 336.
Orinoco, river, 37, 44, 114, 127, 128, 130, 132,
134, 144, 149, 164.
Ornithodorus, 1146.
‘Oronsa SaS:.)255
Orquilla I., 122, 123.
Oryzomys, 301.
Osbeck, Peter, 154.
Osgood, W. H., 3, 301.
Ossification, of limb bones, in young petrels,
592.
Ostrich farms, on Aruba, 121.
Otter, Fuegian, 241.
Otter hunters and hunting, in Fuegia, 14, 16,
19, 241.
Otway water, 38.
Overlapping in racial characters, of skuas, 1007,
1009, 1033.
Over-population at nesting colonies, of petrels,
676.
Owen, Richard, 180.
Owl, short-eared, at Falklands, 22, 186; preying
upon petrels, 731, 789.
Oxyura vittata, 187, 219, 941.
Oyapock, river, 128, 134.
Oyster-catcher, American,
975-978.
black, 99, 170, 241; biography, 988-993.
Fuegian, biography, 985-988.
Galapagos, biography, 981-983.
Patagonian, biography, 983-985.
Peruvian, biography, 978-981.
Oyster-catchers, general account, 973-975.
120; biography,
Pacasmayo, 280.
Pachacamac Is., 96, 144, 283.
Pacheca I., 321.
Pacheco I., 242.
Pachyptila, 167; synonymy of, 325; general
account, 610-615; 619.
banksi, 621, 623.
belcheri, 74, 208, 613, 614, 615, 618, 624, 629.
desolata, 71, 225, 227, 232, 571, 609, 613, 614,
617, 618, 620, 623, 624, 626, 630, 632, 1030.
forsteri, 74, 213, 612, 613, 614, 615, 622, 623,
624, 630, 631.
turtur, 610, 613, 614, 630, 631.
turtur crassirostris, 613.
vittata keyteli, 212, 623.
vittata salvini, 612.
INDEX
Pack-ice, 68, 69; at Bouvet I., 233; as barrier to
distribution of petrels, 644, 724.
Pagodroma nivea, 71, 223, 225, 227, 231, 232,
234, 633.
Painter, Callao, 278, 279.
Paita, 29, 96, 267, 268, 275.
Pajaro, punta, 235.
Pajaros I., 321.
Palena, rio, 246.
Palm, cabbage, 130.
chonta, 256.
coconut, 141, 145, 156, 164, 318.
royal, 130.
Palmar, point, 168.
Palmas, isla de las, 316.
Palmer, T. S., 3.
Palmer Land, 229.
Pampero, 41, 48, 163, 183.
Panama, gulf of, 44, 103, 144, 313, 316, 320.
isthmus of, readily crossed by pelicans, 807,
812; by man-o'-war birds, 920; by Atlantic
race of oyster-catcher, 976, 981; by jaegers
on migration, 1036; effective barrier against
the passage of boobies from ocean to ocean,
832, 854, 863.
Pan-antarctic, 73, 76.
Panting of young, of penguins,.351; of petrels,
592; of boobies, 835, 866.
Pard, 45, 90, 134, 136, 138, 141.
Paracas peninsula, 144, 273, 274.
Paraguana peninsula, 55, 113, 115.
Parahyba, 156.
Parahyba do norte, 141.
Parana, 181, 183, 184.
Parana, rio, 183, 184.
Paranagua, 160, 167.
Paranapiacaba, serra de, 162.
Parasites, of penguins, 378, 389, 414, 461; of
albatrosses, 571; of cormorants, 904.
Parcel dos Abrolhos, 160.
Parental care, physiological basis of, 341.
Paria, gulf of, 114, 119, 124, 127, 128, 130.
peninsula, 115, 118, 119.
Parifias, point, 102, 169, 264, 280, 283, 284, 285,
303.
Parker, F. L., 87.
Parnahyba, rio, 139, 140.
Parry, puerto, 234.
Pasado, cape, 303.
Patagonia, 8, 37, 38, 41, 49, 94, 159, 186, 189,
190, 193, 195, 207, 229, 237, 240, 245, 288,
330; plant zones of, 238.
Patagonian Chile, 235-249.
Patia, rio, 314.
Patos, lagoa dos, 163.
Paul, J. H., 98, 114.
Peak of reproductive period of various birds,
discussed, 504, 658, 730, 843, 894, 1144.
Pearl Is., 320, 321.
Peat-bogs, at Falklands, 204.
Pebble I., 22.
1231
Pebbles, use of in courtship, by penguins, 459;
by boobies, 852.
in stomachs of sea birds (pebbles, gravel,
etc.), 364, 397, 451, 460, 609, 666, 672, 676,
770, 786, 981, 1006, 1052.
Pecking rights, 339, 340.
Pecten, of pelicans, use of, 825.
Pedernales, mouth of Orinoco, 127.
Pediunker, biography, 649-653.
Pedro Gonzales I., 321.
Pejerreyes, 278.
Pelado I., 29, 308, 309.
Pelagic behavior, of skuas, 1034; of certain
gulls, 1041.
Pelagic birds, defined, 327.
Pelagic life, of phalaropes, 995, 998.
Pelagic proclivities, relative, of Pelecaniformes,
793; of tropic-birds, 799; of gulls, 1087.
Pelagic records, of sheath-bills, 1002; of
noddies, 1160.
Pelagodroma marina, 80, 218, 770.
marina hypoleuca, 769.
marina marina, 74, 767.
Pelamis platurus, 311.
Pelecanidae, 327, 807.
Pelecaniformes, 91, 327, 341; general account,
793-796.
Pelecanoides dacunhae, 213.
exsul, 772, 773.
garnotii, 100, 771, 772, 773, 1056.
georgicus, 71, 222, 772, 773, 783.
magellani, 74, 772, 779, 792.
urinatrix, 67, 74, 201, 772, 773.
urinatrix berard, 201, 208, 788.
urinatrix coppingeri, 791.
urinatrix dacunhae, 790.
Pelecanoididae, 323, 327, 771.
Pelecanus occidentalis, 101, 122, 124, 312, 321.
occidentalis californicus, 808.
occidentalis carolinensis, 808, 810.
occidentalis occidentalis, 80, 808, 810.
occidentalis thagus, 100, 252, 293, 819
Pelican, brown, 51, 60, 87, 120, 127, 130, 131,
137, 149, 169, 207, 281, 302, 307, 309, 315,
316; biography, 810-819; 1140, 1159.
Peruvian, 250, 277, 283; biography, 819-827.
West Indian, 281.
Pelicans, general account, 807-810.
Pelotas, 163.
Pembroke, cape, 93.
Penard, E. F., and A. P., 133.
Pefias, gulf of, 11, 244, 245, 249.
Pefias, point, 118.
Penguin, Adélie, 72, 222, 225, 227, 234, 338,
339, 340, 418, 422, 426; biography, 386-
406; 363, 371, 373, 381, 384.
African, 443.
emperor, 32, 72, 222, 225, 330, 332, 334, 336,
341; biography, 354-367; 371, 380, 388,
406, 572.
Galapagos, 443; biography, 466-471.
1232
gentoo, 21, 22, 76, 225; biography, 367-386;
442.
jackass, 420.
johnny, 383, 421.
king, 76, 225, 334, 340; biography, 343-354;
347, 355, 357, 358, 362, 363, 366, 367, 371,
375, 376, 380, 386, 388.
macaroni, 72, 225, 234, 373, 376, 423; biog-
raphy, 432-437; 443.
Magellanic, 10, 75, 99, 190, 196, 241, 250,
252, 336, 353, 376, 421; biography, 437-
452; 455, 456, 461, 468.
Peruvian, 272, 291, 336, 337, 338, 362, 443,
447; biography, 452-465.
tinged, 76, 225, 227, 234, 373; biography,
406-414; 417, 433, 435, 443.
rockhopper, 21, 81, 214, 376, 383; biography,
415-431, 433, 434, 435, 436.
Penguin Is., 196, 209, 288.
Penguins, ancestry of, 329-334.
as food, 440.
as pets, 454, 471.
diagnostic marks on head and neck of, 334,
335.
distribution of, 342, 343.
feathers of, 332, 333.
fossil, 330.
intelligence of, 339.
morphological and physiological relation-
ships of, 334-338.
myopism of, 338, 374.
psychobiologic reactions of, 338-341.
Penrose, F. G., 204.
Perching, of brown pelicans, 813, 814; of
boobies, 856; of cormorants, 913, 914; of
ternlets, 1148.
Percy, William, 30.
Perija, sierra de, 115.
Peripheral survival of certain types of shore
birds and gulls in southern South America,
973, 1041.
Perlas, islas de las, 320.
Pernambuco, 47, 141, 142, 143.
Persea lingue, 251.
Peruvian guano administration, 277.
Peruvian guano islands, 96, 97, 156.
Peruvian littoral expedition, 27.
Pescadores Is., 10.
Peter I., 231.
Peterborough Cathedral (islet), 259.
Peters, J. L., 35, 72, 149, 154, 179, 218.
Petrel, antarctic, 222, 231, 637; biography, 638-
740; 1103.
Atlantic, biography, 702-703.
black, biography, 743-746.
black-capped, 24, 53, 57, 59; biography, 692-
697.
blue, biography, 723-726.
Cook's, biography, 714-717.
De Filippi's, 258.
Elliot's, 272.
Fuegian, 250; biography, 754-757.
INDEX
Galapagos, 99; biography, 697-700.
giant, 375, 571.
great-winged, biography, 689-692.
Hornby’s, 1, 8, 10, 265; biography, 741-743.
Juan Fernandez, biography, 700-702.
Kerguelen, biography, 703.
Kermadec, biography, 704-708.
Leach's, 57, 146; biography, 734-738.
least, biography, 729.
Madeira, 53, 57.
Markham’s, 272.
Mas Atierra, biography, 717-719.
Parkinson's, biography, 647-648.
snow, 60, 72, 224, 234; biography, 633-638;
1103.
soft-plumaged, biography, 711-713.
South Trinidad, 52, 53, 57; biography, 708-
Tabu.
white-throated, biography, 722.
Wilson's, 23, 57, 72, 79, 123, 146, 225, 243,
277; feeding and ‘‘walking”’ of, 232; biog-
raphy, 748-754.
Petroleum fuel oil, distasteful to albatrosses,
563.
Petrolisthes spinifrens, 993.
Petterson, Otto, 108.
Phaéthon aethereus, 80, 99, 101, 102, 123, 148,
149, 152, 167, 179, 180, 312.
aethereus aethereus, 797.
aethereus Jimatus, 798.
aethereus mesonauta, 798.
lepturus, 80, 91, 148, 149, 802.
lepturus ascensionis, 802.
lepturus catesbyi, 124, 802.
Phaéthontidae, 327, 796.
Phaétusa simplex, 122, 124, 168, 1042, 1090,
alls i5}5 tute
simplex chloropoda, 1090.
simplex simplex, 140, 1090.
Phalacrocoracidae, 327, 870.
Phalacrocorax albiventer, 74, 198, 208, 323,
423, 871, 879, 891, 897.
atriceps, 76, 201, 225, 227, 232, 323, 871, 878,
879, 888, 892, 893, 900, 903.
atriceps atriceps, 881.
atriceps georgianus, 222, 885.
auritus, 793.
bougainvillii, 100, 252, 266, 277, 287, 293,
304, 813, 820, 871, 875, 878, 899, 1055, 1056.
capensis, 901.
carunculatus, 878.
gaimardi, 74, 99, 196, 200, 251, 323, 871, 873,
897, 911.
magellanicus, 74, 198, 208, 871, 895, 900.
olivaceus, 76, 99, 109, 122, 124, 163, 168, 170,
202, 207, 252, 291, 322, 793, 813, 870, 871,
875.
olivaceus hornensis, 915.
olivaceus mexicanus, 109, 910.
olivaceus olivaceus, 909.
punctatus, 874.
sulcatus, 266.
INDEX
Phalarope, northern, biography, 997-998.
red, 250; biography, 996-997.
Wilson's, biography, 998-999.
Phalaropes, be i account, 993-995.
Phalaropodidae, 327, 993.
Phalaropus antarcticus, 997.
fulicarius, 258, 996.
Philadelphia Academy of Natural Sciences, 33.
Philippi, R. A., 265, 266.
Phoebetria, generic characters of, 491.
fusca, 74, 213, 494.
palpebrata, 71, 213, 222, 232, 234, 497.
Phoenicopterus chilensis, 187.
ruber, 122, 166.
Photosynthesis, in the sea, 62, 63.
Phylica, 1162.
arborea, 210.
nitida, 210, 216.
Physalia, 164, 563.
Physiological exhaustion, in birds, 50, 51.
Phytoplankton, 61, 71, 279.
Pica, 286.
Piedras, punta de las, 184, 185.
Piérola, Nicolas de, 295.
Pigmentation of feathers, in relation to rate of
abrasion, in skuas, 1025.
Pigs, at Tristan da Cunha, 217.
Pilar, cape, 243.
Pinaroloxias inornata, 317.
Pinnixa transversalis, 672.
Pintail, brown, 186.
Pinzon, 126.
Piquero, 272, 307; biography, 838-846.
Pirie, J. H. H., 213.
Pisco, 96, 272, 274, 275.
Pisco bay, 10, 31, 145, 274, 287.
Piura, river, 283.
Placodium, 221.
Plagiusa chabrus, 981.
Plankton, 63, 78, 86, 102, 282
counts, 90, 93.
Plant distribution, controlling influences of,
163, 164.
Plata, rio de la, 12, 47, 73, 74, 94, 169, 183,
184.
Platform I., 146.
Plate, R. S., 115, 116.
Plaxiphora setiger, 963.
Play, fondness for, of penguins, 399; of sheath-
bills, 1005S.
Plover, black-bellied, 140, 275, 306.
Falkland, 188, 251.
golden, 132; flight of, 1104.
ring-necked, 275.
snowy, 251, 275.
Wilson's, 140.
“Plowing,"’ of skimmers, and its function,
1175, 1176, 1177.
Plumage, specialized, of phalaropes, 993.
Plumage-pattern, of whale-birds, 619, 620, 622,
626.
1233
Plumage problems, of boobies, 864.
sequences, of penguins, 351, 352, 363, 364,
365, 379, 380, 381, 401, 402, 403, 413, 414,
419, 449, 450, 463, 464; of Procellarii-
formes, 479; of albatrosses, 504, 505,
518, 520, 523, 524, 537, 548, 549, 550, 552,
558, 559, 560, 562, 579, 580; of petrels, 586,
587, 588, 592, 593, 606, 617, 627, 639, 680,
683, 685; of storm petrels, 737, 748; of
diving petrels, 778, 783, 786; of pelicans,
826; of boobies, 829, 857, 867; of cor-
morants, 882, 884, 888, 893, 898, 899, 911;
of man-o'-war birds, 922, 924, 936; of
sheath-bills, 1004, 1005; of skuas, 1025,
1028; of gulls, 1040, 1054, 1067, 1076, 1080,
1083, 1084; of terns, 1099, 1101, 1113, 1116,
1118, 1119, 1145, 1146, 1157.
Plumage variation correlated with geographic
distribution, 974, 979.
Plumes and feathers, traffic in, 675, 802.
Pluvialis dominica, 132, 187.
Poa flabellata, 204, 221, 370, 422, 748, 789.
Podilymbus podiceps antarcticus, 187.
Polar front, see Antarctic convergence.
Polonia, cape, 169, 170, 171.
Polyachyrus, 278.
Polyandry, in man-o’-war birds, 931.
Pontederia, 181.
Population, of guanay colonies, 902.
pelagic shift in, as correlated with season,
543, 544, 604, 1034.
Pororéca, 135, 136.
Porphyra umbilicalis, 947.
Porphyriornis comeri, 210.
nesiotis, 217.
Porpoising, of penguins, 384, 385, 399, 427, 428,
441, 450, 465.
Port of Spain, 127.
Portenko, L., 293.
Porto Alegre, 163.
Porto Seguro, 143.
Portuguese man-o'-war, 78.
Porzana spiloptera, 187.
Post Office bay, 267.
Post-prandial behavior of young pelicans, 814,
816.
Posture, sitting, of penguins, 453.
Posturing, of penguins, 459; of albatrosses,
492, 513, 522, 534, 535, 551, 567; of petrels,
599, 637, 640; of skuas, 1029; of gulls, 1057,
1069; of terns, 1128, 1136.
Potamalosa notacanthoides, 1016.
Potoyunco, biography, 773-779.
Pouch-feathering, of whale-birds, 624.
‘Pourquoi Pas?’, 231, 232.
Preadaptation, and its relation to distribution,
388, 389, 411.
Precipitation, cause of, 40, 48.
local variation in, along Caribbean coast, 113,
115.
1234
at Venezuelan coastal islands, 116, 123; in
eastern Caribbean, 119; at Mexiana I., 137;
in northeastern Brazil, 140, 141; at Fer-
nando Noronha, 146; at Ascension I., 152,
1126; at Parahyba, Recife, Bahia, 156; at
Ilheos, Rio de Janeiro, 157; at Santos, 163;
at South Trinidad, 171; at St. Helena, 178;
of Argentina, 192; at Falklands, 205; at
Gough I., 211; at Tristan da Cunha, 216,
217; at South Georgia, 221; at South Ork-
neys, 226; in Antarctic archipelago, 229;
at Staten I., 235; in Tierra del Fuego region,
237, 239, 242, 244; at Juan Fernandez, 255;
at San Felix and San Ambrosio Is., 259;
on desert west coast, 264, 268, 269, 271,
283, 285, 286; on Peruvian Is., 289; at
Galapagos Is., 298, 301; in Ecuador, 304,
305, 307, 308, 309, 313; at El Muerto, 307;
along Naya river, 315; at Gorgona I., 315;
in Buenaventura, 316; along Panamanian
coast, 316; at Pearl Is., 321.
influence of, on burrowing penguins, 447,
448.
Predatory feeding habits, of man-o’-war birds,
993; of skuas, 1014, 1016, 1019, 1020, 1023,
1025, 1030, 1031, 1034; of jaegers, 1034,
1038, 1039; of gulls, 1055, 1063, 1069, 1070,
1086.
Priocella antarctica, 71, 102, 180, 223, 225, 227,
232, 234, 235, 258, 596.
Prion, Banks's, 628.
fairy, biography, 631-633.
Prion ariel, 632, 633.
Procellaria aequinoctialis, 76, 77, 99, 102, 168,
188, 208, 213, 222, 225, 232, 235, 250, 258,
272, 571, 741, 1025.
conspicillata, 643.
parkinsoni, 647.
Procellariidae, 327, 584.
Procellariiformes, 1, 2, 78, 89, 179, 207, 231,
258, 327, 341, 558, 560, 610, 612, 621, 628;
general account, 471-489.
Procelsterna, 1043.
albivitta, 261, 1147.
albivitta imitatrix, 1148.
cerulea, 79, 260, 262, 1147, 1149.
Prolactin, 341.
Promiscuity, apparent, in preliminary stages of
courtship, 679.
Proportion, numerical, of color phases, in
breeding populations of petrels, 707; of
boobies, 864, 865.
morphological, of man-o’-war birds, 925,
926, 930.
relative morphological, in king and emperor
penguins, 357.
Prosopis chilensis, 278.
Prosperous Bay hill, 180.
Protective coloration, 364; effectiveness of, in
fishes fed upon by penguins, 471.
Pseudoprion turtur brevirostris, 630.
INDEX
Psychroteuthis glacialis, 364.
Prterocnemia pennata pennata, 190.
Pterodroma, 619; small petrels of, general
account, 713, 714.
arminjoniana, 79, 175, 690, 708.
brevirostris, 74, 703, 704.
cahow, 697.
caribbaea, 80, 692, 693, 696, 697.
chionophara, 710.
cookii defilippiana, 74, 255, 258, 260, 261,
2622 1/055 fli 20:
cookii orientalis, 258, 714.
externa, 79, 218, 257, 258, 698, 705.
externa externa, 700.
externa tristani, 700.
hasitata, 80, 685, 692, 698.
incerta, 74, 218, 703.
leucoptera brevipes, 722.
leucoptera masafuerae, 79, 255, 258, 705, 719.”
macroptera, 74, 168, 218.
macroptera gouldi, 690.
macroptera macroptera, 689.
mollis, 80, 213, 214.
mollis mollis, 74, 711.
neglecta, 79, 175, 258, 261, 262, 697, 704.
phaeopygia, 80, 99, 101, 313.
phaeopygia phaeopygia, 697.
trinitatis, 710.
Puca, river, 305.
Puerto Montt, 30, 31, 249.
Puffininae, 584.
Puffinus assimilis, 672.
assimilis elegans, 213, 682.
bulleri, 664.
carneipes, 99, 258, 658, 666.
creatopus, 74, 75, 252, 258, 563, 653.
fuscus, 304.
gravis, 74, 75, 138, 188, 216, 218, 653, 664.
griseus, 74, 75, 99, 188, 201, 208, 235, 252,
258, 264, 651, 652, 659, 666, 674.
kuhliana, 683.
kuhlii, 80, 654.
kuhlit borealis, 655.
leucomelas, 654.
lherminieri, 80, 124, 149, 180.
lherminieri ]herminieri, 684.
Iherminieri subalaris, 101, 687.
munda, 683.
pacificus, 697.
puffinus, 168, 674.
puffinus puffinus, 677.
tenuirostris, 673.
Pugnacity, of penguins, 371, 374, 381, 382, 391,
392, 393, 404, 407, 408, 412; of petrels, 601,
608; of oyster-catchers, 986; of sheath-
bills, 1005S.
Pumalin, bay of, 30, 247.
Puna I., 28, 29, 30, 303, 305, 306, 307.
Punta Arenas (see Magallanes).
Pupil of eye, in penguins, 343, 382, 416, 437; in
blue-footed booby, 834; in skimmer, 1175.
INDEX
Pygoscelis, 334, 417, 424.
adeliae, 71, 225, 227, 232, 336, 370, 371, 377,
378, 384, 386, 388.
antarctica, 71, 76, 222, 225, 227, 232, 234,
323, 336, 377, 386, 388, 406, 434.
papua, 76, 171, 208, 222, 225, 2275, 2525 S525
336, 346, 347, 353, 367, 387, 388, 389, 433.
Q
Quarreling, chiefly in territorial rivalry, of
penguins, 349, 350, 391, 436; of cormorants,
906; of terns, 1113, 1128.
Quayle, E. H., 6.
Quebrada Seca, 263.
Queimada Grande I., 161.
Quelch, J. J., 132.
Quell6én, see Cuellon.
“Quest,” 150, 151, 209, 210, 211, 212, 216, 224.
Quilca, 272.
Quiriquina I., 253, 273.
Quito, 28.
R
Rabbits, at East I., Falklands, 22; at Tristan da
Cunha, 217; at South Georgia, 222; at
Kerguelen I., 628.
Rail, flightless, formerly at Ascension, 154.
Raimondi, M. A., 289, 291, 292.
Rain, as a hindrance to albatross flight, 567,
568.
Rainfall, effect of, upon pelicans, 814; upon
boobies, 831; upon man-o’-war birds, 930.
reaction of penguins to, 447, 459.
Rain-shadow, 113, 115, 309.
Rainy season, in relation to breeding period of
birds, 125,
Rallus limicola antarcticus, 187.
longirostris, 166.
Rapacity, of petrels, 600, 608.
Raphithamnus longiflorus, 257.
Rat, spiny, at Gorgona I., 315.
Rat I., 146, 147.
Ratio of adults to young, among king penguins,
350.
Rats, as enemies, of petrels, 481, 746, 769; of
diving petrels, 787, 791; of tropic-birds,
807.
at St. Helena, 217, 222, 319; at Tristan da
Cunha, 481, 616, 617; at South Georgia,
625, 646.
Ray, giant, 285, 304, 311, 1139.
Rayas, 248.
Razo I. (Cape Verdes), 179.
Reaction, to continental coast, of boobies, 855.
to danger, of penguins, 363, 372.
to extreme cold, of sheath-bills, 1005.
to environmental conditions, of steamer
ducks, 966.
to light, of noddies, 1154.
to various stimuli, of guanay, 907.
to weather conditions, of terns, 1112.
1235
Reactions to other organisms (chiefly enemies),
of penguins, 400, 401, 404, 405, 407, 408,
416, 427, 429, 436, 438, 448; of alba-
trosses, 514, 529, 535, 536, 553, 554, 555,
564, 571; of petrels, 618, 626, 666, 670, 706;
of storm petrels, 746; of tropic-birds, 800;
of boobies, 837, 858, 868, 869; of cormor-
ants, 906, 918; of ducks and geese, 944,
947, 949, 950; of steamer ducks, 964, 968;
of oyster-catchers, 986, 992; of sheath-
bills, 1003, 1004, 1005; of skuas, 1022, 1023,
1025, 1026, 1027, 1028, 1031, 1032; of gulls,
1047, 1048, 1057, 1063, 1066, 1067; of terns,
1096, 1112, 1115, 1116, 1120, 1128, 1130,
1135, 1146, 1149, 1160, 1164, 1165; of
skimmers, 1178.
Recife de Pernambuco, 47, 140, 141, 156.
Recognition marks, of penguins, 467, 468, 469;
of Procellariiformes, 488.
Recognition of young, by pelicans, 816; by
terns, 1129, 1157.
Rectrices, occasional greater length of, in
juvenal plumage, 765.
Red seas, 98, 272, 610.
Redonda I., 158.
Reed, C. T., 32.
Reef corals, 143-145, 164, 171.
Regurgitation, as a defensive reaction, or re-
sponse to annoyance, in albatrosses, 511,
514, 517, 520, 529; in petrels, 592, 593, 599,
605, 647, 737, 753, 759.
Reichenow, Anton, 155, 234.
Reindeer, at South Georgia, 222.
Reiser, Ormar, 139.
Re-laying, after loss of first eggs, by penguins,
375, 448; by albatrosses, 511, 512, 517; by
petrels, 637; by skuas, 1019, 1033; by terns,
1127, 1156.
failure in, of petrels, 680.
Reloncavi ery
Renard, Abel, 196.
Rendahl, Hjalmar, 321.
Representative species, in petrels, 698, 700, 702,
709, 765.
Reproduction, biological function of, 457.
Reproductive cycle or rhythm, the length, type,
and variations of, among penguins, 445;
among albatrosses, 561, 562, 574; among
Poor 645, 655, 664, 692, 695, 790; among
oobies, 829, 850; among terns, 1127, 1167;
among skimmers, 1173.
Resacas, 135.
Respiration, of penguins, 390.
rapidity of, in petrels, 737.
Restinga, 195.
Restinga de Marambaia, 144.
Resting, of various terns, on muddy points,
1093; on cliffs, 1113, 1165; on wreckage and
flotsam, 1104; on sandy beaches, 1111; on
fences, 1116; on water, 1118, 1120.
Restlessness, during courtship period, of
petrels, 725; of terns, 1128.
1236
Reyes, isla de los, 253.
Reynolds, P. W., 241.
Rhaphithalmus cyanocarpus, 251. ;
Rhea, common, 190.
Darwin's, 190.
Rhea americana albescens, 190.
Rhizophora, 132.
manglier, 163.
Ribeiro, A. de M., 149, 173.
Ribera, Emilio, 266.
Richards, Guy, 6.
Richards, T. W., 88.
Richards deep, 258.
Richardson, W. B., 30, 314.
Richmond, C. W., 35, 121.
Ridgway, Robert, 3.
Riggs, E. S., 196.
Rincones, 185.
Rio de Janeiro, 23, 41, 47, 48, 87, 109, 130, 142,
144, 149, 155, 157, 159, 161, 202, 263.
Rio Douglas mission, 15.
Rio Gallegos, 16, 17, 18, 19, 237.
Rio Game do Norte, 46, 140.
do Sul, 167.
Rivalry, interspecific, among penguins, 389.
Rivers, importance of, in enrichment of the
sea, 38.
importance of, to certain terns, 1091, 1133;
to skimmers, 1169, 1172, 1173.
Roaring Forties, 48, 324.
Robinson, Wirt, 118, 121.
Rocas Reef, 89, 130, 144, 145, 146, 159.
Rocha, department of, 170.
Rockwell, R. H., 171, 173, 176.
Rodgers bank, 158.
Rodriguez, rio, 30, 247.
Rollers, 155-156, 217, 271.
Roques I., 124.
Ross, J. C., 86, 150, 151, 204.
Ross sea, 66.
Rothschild, Walter, 4, 35.
Rothschild collection, 326.
Galapagos expedition, 4.
Round I., 209.
Rowettia goughensis, 213.
Royal bay, 221.
Royal Geographical Society, 69.
Royal Scottish Museum, 33.
Rubia, punta, 190.
Rudolph, W. E., 194, 237, 238, 240, 247, 264.
Rie, E. A. de la, 314, 315.
Rumex, 215.
Ruppia maritima, 275.
Rustad, Ditlef, 71, 73.
Rynchopidae, 327, 1169.
Rynchops nigra, 122, 124, 1169.
nigra cinerascens, 137, 1170.
nigra intercedens, 140, 168, 1170.
nigra intermedia, 1170.
nigra nigra, 1170.
nigra oblita, 1170.
INDEX
Saboga I., 321.
Sachse, Walter, 234.
Sail rock, 23.
Sala y Gomez Is., 262, 263, 267.
Sala Honda, 314.
Salado, rio, 185.
Salango I., 309.
Salaverry, 9, 270, 271, 276.
Salinas Falsas bay, 139.
Salinity, relative, in various zones, 63, 68, 69,
72, 77, 78, 83, 102, 106, 138, 163, 169, 184,
305, 321.
Salt lagoons, special avifauna of, in Argentina,
188.
Salut Is., 133.
Salvadori, Tommaso, 235.
Sama valley, 286.
San Ambrosio I., 31, 68, 75, 79, 81, 99, 258-
262, 267.
San Antonio, 191, 192; likened to Chicago, 190.
San Antonio, cape, 183, 185.
San Blas, bay, 190.
San Carlos, 10, 250.
San Diego, cape, 20.
San Felix I., 31, 66, 75, 79, 81, 99, 258-262, 263,
267, 312.
San Francisco, cape, 144, 309.
San Gallan I., 10, 144, 200, 273, 274, 275, 276,
277, 278.
San Jorge, golfo de, 194, 195, 197.
San José, gulf of, 190.
San José I., 321.
San Juan Bautista, 257.
San Julian, port, 196, 198.
San Lorenzo, cape, 307, 309.
San Lorenzo I., 10, 277.
San Marcos, Museum of the University of, 33.
San Matias, gulf of, 190, 191, 199.
San Miguel I., 321.
San Peo I., 11, 248.
San Rafael glacier, 240, 246. .
San Sebastian bay, 17, 20.
San Tadeo, rio, 245.
San Vicente, cape, 19.
Sandalwood, 256.
Sanderling, 140, 248, 275.
Sandpiper, buff-breasted, 140.
least, 140.
semipalmated, 140, 275.
spotted, 132, 140, 275, 281, 307, 312.
western, 275.
Sanford Ge 25316:
Santa Ana, 305.
Santa Barbara I., 158.
Santa Catharina I., 130, 163, 164.
Santa Clara I. (Ecuador), see El Muerto.
Santa Clara I. (Juan Fernandez), 11, 75, 254,
255, 256, 257.
Santa Cruz, river and port, 17, 18, 191, 192, 194,
196, 197, 198, 201.
INDEX
Santa Elena (Ecuador), 279, 306, 307, 308, 311.
Santa Elena bay, 144, 308.
peninsula, 29, 30, 268, 307, 308.
Santa Elena, punta, 102, 303, 311.
‘Santa Elisa,’ 272, 273, 276.
Santa Inés I., 243.
Santa Luisa, 265.
Santa Maria I., 252, 253.
Santa Marta, 113, 115.
Santa Martha Grande, cape, 163, 167.
Santa Rosa (Venezuela), 116, 273.
Santelmo I., 321.
Santiago (Chile), 249.
Santiago, rio, 309.
Santo Amaro I., 161.
Santos, 23, 159, 161, 167.
bay of, 161, 162.
Sao Francisco, river, 142, 156.
Sado Luiz do Maranhao, 90, 139.
Sao Paulo, 87, 140, 167, 168.
Sdo Roque, cape, 37, 40, 41, 42, 44, 46, 86, 87,
130, 131, 139, 140, 142, 156, 159, 169.
Sado Sebastiado current, 160, 161, 167.
Sao Sebastiado I., 130, 161, 167, 168.
Sao Thome, cape, 157, 159, 168.
Sargasso sea Gail related ‘‘Sargasso’’ areas),
25, 52; transparency and blueness of, 83,
84; paucity of surface life and birds in, 84,
88-92, 97, 804.
Sarmiento channel, 30, 243.
Sarmiento, Mount, 13.
Saunders I., 22, 225.
Savannahs, 280, 305, 306.
Scarcity of certain storm petrels in waters near
nesting ground, 737, 758.
Schizopoda, 628.
Schokalsky, Jules, 43.
Schomburgk, Richard, 129, 131.
Schott, Gerhard, 76, 94, 96, 103, 106, 159, 297,
316.
Schweizer, Gustav, 34.
Sclater, P. L., 154.
Scooping, a method of feeding of whale-birds,
488, 621.
Scopelidae, 378.
Scorpaena histrio, 915.
Scotia arc, 35, 66, 197, 202, 210, 212-223.
‘Scotia’ expedition, 210, 211, 213, 223, 225, 226.
Scouler, John, 254.
Sea bird distribution, principles of, 623.
Sea birds, as marine organisms, 324.
Sea-elephant, 169, 179, 211, 227, 245, 562.
Sea-ice, relation to range, of petrels, 604.
Sea-leopard, 179, 227, 372, 400, 425, 891; habits
of, 414.
Sea-lion, 165, 169, 190, 237, 241, 245, 270, 283,
305, 442, 465, 470, 1144, 1146; as enemy of
pelican, 827.
Sea turtles, 165, 1126.
Seawater, drinking of, by birds, 337, 464, 470,
681, 1129, 1157.
1237
Seal, crab-eater, 227.
Weddell, 227; West Indian, 169.
Seal rookeries, at Coronilla Is., 168.
Seale, R. F., 180.
Sealing industry, at Lobos Is. (Uruguay), 170.
Seasickness, on deck, of albatrosses, 517.
Seasonal movements of migrant petrels in North
Atlantic, 661, 662.
Sechura bay, 267.
Sedentary characteristics, of royal albatross,
579; of Galapagos shearwater, 688; of
certain petrels, 760; of certain forms of
diving petrels, 772; of cormorants, 886,
913; of man-o'-war birds, 919; of steamer
ducks, 961; of dusky gull, 1047; of gulls,
1085; of South Georgian tern, 1111; of
fairy terns, 1166.
Seed snipe, 188.
Segregation, specific, in nesting habits of closely
related birds, among Procellariiformes, 478,
517, 705, 714; among man-o’-war birds,
938.
Selkirk’s cave, 257.
Senckenberg Museum, 33.
Senguerr-Chico system, 195.
Sefiora I., 321.
Sefiorita I., 321.
Sense, of direction, of penguins, 338; of tropic-
birds, 804, 805; of terns, 1105, 1122, 1129,
1131.
of sight, of boobies, 829.
of smell, of Procellariiformes, 488; of alba-
trosses, 560, 563, 564; of giant fulmar, 594,
595; of cape pigeon, 609; of shoemaker,
647; of boobies, 829; of sheath-bills, 1002;
of skuas, 1017, 1031; of gulls, 1069.
Sense organs, of emperor penguin, 360.
Sequoia, 231.
Serpent's mouth, 119.
Sesuvium Portulacastrum, 278.
Sex recognition, in penguins, 340.
Sex rhythm, in birds, 340, 341.
Sexes, unequal number of each, with females
preponderating, of jaegers, 1035, 1039.
Sexual selection, of Procellariiformes, 479; of
albatrosses, according to plumage differ-
ences, 558.
Seymour I., 231.
Shackleton, Ernest, 210.
Shag, antarctic blue-eyed, biography, 888-891.
king, 207; biography, 891-895.
Magellanic, 250.
Magellanic blue-eyed, biography, 881-885.
red-footed, 250; biography, 873-878.
rock, 196, 218, 242; biography, 895-899.
South Georgian blue-eyed, biography, 885-
888.
Shags, as food, 897.
Shags, blue-eyed, 251, 253; general account,
878-881.
Shanahan, E. W., 36, 39.
Shark, hammer-head, 284.
1238
Sharks, abundance around St. Paul Rocks, 151.
as enemies of pelicans, 827.
Shearwater, Audubon’s, 23, 24, 80, 123; biog-
raphy, 684-687.
flesh-footed, 99; biography, 658-660.
Galapagos, biography, 687-689.
gray-backed, biography, 664-666.
greater, 189; biography, 660-664.
Manx, 168, 189; biography, 677-681.
pink-footed, 250, 258, 272; biography, 653-
658.
short-tailed, biography, 673-676.
sooty, 79, 99, 189, 235, 243, 250, 272, 273, 277,
298, 313; biography, 666-673.
Tristan, biography, 682-684.
Shearwaters, least, general account, 681-682.
Sheath-bill, 227, 231, 232, 401, 436; biography,
1000-1006.
Sheath-bills, general account, 999-1000.
Shedding, of sheath of mandibles, by king
penguin, 352; by oyster-catchers, 983.
Sheep, southernmost ranch, 15.
thick wool in Fuegia, 19.
as a zonal index, 490, 491.
at Falklands, 22, 204, 206; at South Georgia,
222; at Bleaker I., 422; in Tierra del Fuego
region, 240, 242.
Sheep-ranching, etc., effect of upon concen-
tration of gulls, 1069, 1076, 1086.
Sheppard, George, 279, 304, 305, 308, 311.
Shifting, Soeaic of Peruvian pelican popu-
lation, 822.
Ship-followers, individual sea birds as, 496,
499, 500, 508, 544, 545, 546, 562, 563, 564,
575, 603, 604, 618, 621, 622, 624, 626, 651,
712, 1070.
Ships, petrels attracted aboard, 673, 728, 729,
759, 770.
Shoal bay, 16.
Shoemaker, 225, 250; biography, 641-647.
Shoreward reaction of wounded skuas, 1028.
Shoveller, 186, 188.
‘Silver Spray,’ 28, 29, 285, 304, 305.
Simmons, G. F., 32, 138, 145, 146, 148, 153, 173,
174, 181.
Simpich, Frederick, 124, 133, 135.
Simpson, G. G., 35, 192, 195.
Siriba I., 158.
Size, relative, absolute, and variation in, among
sea birds, in penguins, 418.
range in Procellariiformes, 475, 476; in alba-
trosses, 540-543, 547, 573, 582, 583; in
three species of steamer ducks, 956.
Skeletal proportions of storm petrels, 744, 745,
746.
Skeletons, of birds, at St. Helena, 180.
stranded, of whales, 185.
Skimmer, black, 56, 99, 305; biography, 1169-
1178.
Skimmers, general account, 1169.
Skorlich, M. P., 28.
Skottsberg, Carl, 244, 255.
INDEX
Skua, antarctic or south polar, 32, 73, 233, 365,
400; biography, 1016-1020.
brown, biography, 1023-1033.
Chilean, 272; biography, 1013-1016.
cinnamon, 250, 252.
Falkland, biography, 1020-1023.
Tristan, biography, 1033-1034.
Skua, habits of, 480.
as agency affecting evolution of petrels, 481.
immunity of storm petrels from attacks of,
Uk
Skuas, general account, 1006-1013.
Skyring bay, 38.
Slaughterhouse, as attraction to man-o'-war
birds, 120.
Sleep and sleeping, time, attitude, circum-
stances, etc., of penguins, 353, 382, 405;
of Procellariiformes, 647, 706; of boobies,
867, 868, 869; of cormorants, 894, 918; of
man-o'-war birds, 935; of skuas, 1029; of
terns, 1128.
Sleight, port, 11.
Smashing, by dropping from the air, of shells
by skuas, 1029; of eggs and shells by gulls,
1046, 1070, 1071.
Smith, H. H., 126, 135, 156.
Smith, H. M., 168, 170, 171.
Smith, J. R., 244, 267.
Smithsonian Institution, 3.
Smoke I., 16.
Smooker, G. D., 123.
Smyth channel, 30, 243.
Snails, 170; shells of, used as nest eggs by
boobies, 836, 837, 852.
Snakes, bird-eating, 162, 285, 315, 319.
Snethlage, Emilie, 139.
Snipe, robin, 140.
Snodgrass, R. E., 319.
Snow, eating of, by penguins, 395; by sheath-
bills, 1006.
Snow Hill I., 32, 231. )
Soaring, of pelicans, 817; of man-o’-war birds,
929.
Social behavior, of albatrosses, 552, 558.
Social order, in birds, 339.
intraspecific, among penguins, 393, 394, 398.
Sola I., 123.
Solano, bahia, 195.
Solitary habits, nesting of sooty albatross, 501.
of skuas, at sea, 1034.
Sophora tetraptera goughensis, 210.
South America, geographic description, 35-38;
meteorology, 38-59; great southward ex-
tension of, 50, 71; ornithological circum-
navigation of, 110-322; physical char-
acteristics, 323; as center of avian dis-
persal, 772, 773.
South Georgia, 26, 48, 49, 67, 69, 70, 76, 92,
93, 109, 192, 200, 201, 202, 205, 210, 213,
218, 219, 224; expedition to, 25; reduction
of glaciation at, 371.
INDEX
South Orkney Is., 109, 200, 201, 218, 220, 224,
225-227, 228, 229, 230.
South Sandwich Is., 219, 223-225, 228, 324.
South Sea pass, 15.
South Shetland Is., 76, 93, 109, 200, 201, 213,
218, 224, 228-229.
South Trinidad I., 23, 26, 32, 79, 144, 146, 149,
155, 171-176, 181, 214.
Southeast I., 158.
Spacing of nests, reaction responsible for, 901,
902.
Sparrow cove, 21.
Spartina arundinacea, 210, 215, 428.
Spatula platalea, 187, 202.
Speciation, rate of, in Pelecaniformes, 793.
Specific characters, as revealed in nestling
petrels, 716.
Speed, on land or ice, of penguins, 390.
swimming, of penguins, 384, 399, 406, 424,
428, 450, 461, 470; of steamer ducks, 959,
970.
in flight, of albatrosses, 509; of diving petrels,
787, 791; of skuas, 1031.
Speery I., 180.
Sphenisciformes, 327, 329.
Spheniscus, 323, 334, 336, 442.
demersus, 443, 449, 455, 457, 458, 467, 468.
humboldti, 100, 199, 441, 443, 444, 452, 467,
468, 470, 1055.
magellanicus, 74, 99, 167, 171, 188, 199, 201,
208, 252, 258, 419, 437, 455, 456, 457, 467,
468.
mendiculus, 101, 455, 466.
Sphenodon punctatus, 659, 666, 717.
Spiess, F., 86, 87, 90, 150, 158, 178, 181, 191,
192, 211, 224, 229, 233, 237.
Spinning, of phalaropes, 995.
Spix, J. B. von, 167.
Spoonbill, roseate, 119, 132, 137, 281.
Sporadic appearance of shearwaters in coastal
waters, 669.
Squids, as food of penguins, 347.
vertical range of, 869.
St. Elmo's fire, 183.
St. George, cape, 245.
St. Helena, 32, 77, 80, 109, 149, 154, 155, 176-
181, 208.
forests of, 171, 173, 175, 179, 271.
St. Michael's mount, 146, 153.
St.-Johnston, T. R., 289.
St. Paul Rocks, 86, 87, 89, 144, 150, 151, 159,
263, 280, 300.
St. Thomas I., 23, 24.
Stain, ear, of albatrosses, 559, 560.
Standard atmosphere, in relation to flight, of
albatrosses, 532, 533.
Standing on water, of Procellariiformes, 485,
486, 565, 752.
Stanley, port, 12, 20, 21, 22, 49, 204.
Starveling young, resulting from territorial
competition, of petrels, 707.
1239
Staten I., 19, 37, 48, 70, 197, 202, 218, 219, 234-
235, 237.
Steamer duck, Falkland flightless, biography,
964-968.
flying, biography, 968-972.
Magellanic flightless, biography, 957-964.
South American flightless, 199.
Steamer ducks, 74, 242, 246, 249, 323; general
account, 951-957.
Steaming, of steamer ducks, 951, 958, 959, 964,
965, 966, 970.
Stefansson strait, 229.
Steffen, Hans, 246.
Steganopus tricolor, 188, 998.
Stephen, A. C., 35.
Stercorariidae, 327, 1006.
Stercorarius longicaudus, 189, 1038.
parasiticus, 189, 1037.
pomarinus, 1035.
Sterility, relation to moult of petrels, 600;
to migration of petrels, 604, 606.
Sterna albifrons, 1133.
albifrons antillarum, 122, 124, 1136.
albivitta, 79.
anaethetus, 80, 122.
anaethetus melanoptera, 1118.
anaethetus nelsoni, 1120.
dougalli, 122, 124.
dougalli dougalli, 1116.
fuscata, 80, 99, 101, 122, 124, 145, 148, 176,
181, 258, 261, 263, 273, 325, 1120, 1145,
1149.
fuscata crissalis, 302, 1121, 1124.
fuscata luctuosa, 1121.
hirundinacea, 74, 99, 109, 165, 167, 168, 170,
189, 193, 194, 200, 208, 227, 929, 992, 1016,
1042, 1043, 1085, 1094, 1096, 1105, 1107,
1109, 1146.
hirundo, 122, 124, 272, 1118.
hirundo hirundo, 1098.
lorata, 100, 272, 1042, 1134, 1138.
luctuosa, 1132.
macrura antistropha, 1103, 1107.
paradisaea, 108, 138, 258, 272, 1099, 1101,
1107.
superciliaris, 140, 168, 1042, 1132, 1133, 1137.
trudeaui, 168, 187, 261, 1114.
vittata, 76, 108, 109, 154, 200, 225, 227, 232,
1042, 1095, 1101, 1102, 1103, 1105, 1106,
1107, 1108, 1111.
vittata bethunei, 1106.
vittata georgiae, 222, 1106, 1109.
vittata vittata, 1106.
Sterninae, 1040.
Stevenson, W. B., 287.
Stewart I., 243.
Stilt, black-necked, 302.
Stockholm Museum, 33.
Stokes, Captain, 243.
Stolephorus, 1136.
Stoltenhoff brothers, 427, 430, 431, 713.
Stoltenhoff I., 216.
1240
Stomach oil, of Procellariiformes, nature, com-
position, function, and industrial use of,
473, 474, 610, 671, 675, 759, 770.
Stone, L. M., 28.
Stone, Witmer, 35.
Stone reefs, 143, 156.
rivers, 204.
Stooping, method of feeding, of Procellarii-
ormes, 487.
Storm petrel, Bangs’s, biography, 734.
black-bellied, biography, 764-767.
Elliot's, biography, 757-759.
Galapagos, biography, 729-731.
gray-backed, biography, 746-748.
Lowe's, biography, 759-760.
Madeiran, biography, 732-733.
Markham’s, biography, 739-741.
Peruvian, biography, 731-732.
Tristan, biography, 762-764.
white-bellied, biography, 760-762.
white-faced, biography, 767-770.
Storm petrels, general account, 726-728.
Storm-waves, 55.
Storms, as hazards to petrels, 620, 628, 633.
Straying, prevention of, by young king pen-
guins, 350, 351; by gentoo penguins, 379.
Stresemann, Erwin, 35, 264.
Sturgis, B. B., 321.
Suaeda microphylla, 260.
Sub-Antarctic zone, 65, 67, 68, 69, 72-74, 82,
87, 93, 108, 109, 211, 490, 612, 613, 657,
714, 765, 1105.
Subcutaneous cushion, of boobies and pelicans,
795.
Submergence, depth and time of, among pen-
guins, 399, 427, 451, 460, 461; among Pro-
cellariiformes, 621, 640, 790; among
boobies, 829, 838, 851; among cormorants,
873, 877, 899, 915.
Subspeciation, discussion of, in penguins, 417,
455; in albatrosses, 526, 527, 582, 583, 584;
in petrels, 612, 712, 715, 732, 734, 736;
in storm petrels, 755, 756, 762, 768; in
diving petrels, 791, 792; in tropic-birds,
797; in pelicans, 807, 808, 810; in boobies,
832, 833, 847, 848, 855, 860, 863, 864; in
cormorants, 879, 880, 916; in man-o’-war
birds, 921, 927, 928; in kelp goose, 946;
in oyster-catchers, 974, 975, 977, 979; in
skuas, 1006, 1007, 1008, 1012, 1021, 1024,
1033; in gulls, 1059, 1073, 1075; in terns,
1091, 1103, 1106, 1120, 1124, 1149, 1163,
1168; in skimmers, 1172.
Sub-Tropical convergence, 66, 67, 73, 75, 81,
94, 211, 612, 648, 691, 920, 939, 1149.
Sub-Tropical zone, 65. 67, 77-78, 165, 617, 645.
Subsidence, in southern Brazil, 37; near Bahia,
157; near Rio de Janeiro, 159.
Sucio, 111.
Sugar-cane, 163, 298.
Sugarloaf hill, 180, 257.
INDEX
Sula antiqua, 266, 304.
autumnalis, 864.
dactylatra, 80, 99, 101, 102, 123, 146, 148,
152, 153, 158, 168, 175, 261, 262, 311, 312,
321, 827, 831, 840, 858, 863, 938.
dactylatra dactylatra, 846.
dactylatra granti, 846.
leucogaster, 91, 124, 146, 148, 150, 154, 168,
75827
leucogaster brewsteri, 855.
leucogaster etesiaca, 80, 102, 313, 315, 319,
855, 859, 863.
leucogaster leucogaster, 80, 854.
nebouxii, 80, 101, 262, 312, 322, 813, 827,
829, 840, 842, 852, 858.
nicolli, 864.
piscator websteri, 302.
sula, 80, 101, 124, 146, 148, 153, 154, 168,
175, 319, 321, 827, 831, 854, 861.
sula websteri, 863. :
variegata, 100, 262, 266, 277, 290, 293, 813,
820, 827, 833, 838, 848, 914.
Sulidae, 327, 827.
Sun, desiccating power of, on Patagonian coast,
191.
deleterious or fatal effect of upon eggs and
young birds, 867, 936, 981.
Sun-fish, 296.
Sunlight, reaction to, by birds, 376; by pen-
guins, 459; by boobies, 844; by skuas, 1029.
Sunning reaction, of cormorants, 914, 918.
Surf-bird, 275.
Surf days, 155.
Surface-breeding, of petrels, 719.
Surface-dancing, of Mother Carey’s chickens,
488.
Surface-nesting, of petrels, 705, 708; of burrow-
ing petrels, 770.
Sverdrup, H. U., 96.
Swainson, William, 264.
Swallow, bank, 303.
barn, 303.
black-necked, 162.
cliff, 303.
Swarth, H. S., 298, 301, 302, 303, 317.
Sweat glands, absence of in birds, 337.
Swedish expedition, 231, 330.
Swimming, ability of, of noddies, 1154.
aversion to, of certain terns, 1104, 1120, 1125,
1127, 1154.
loss of power of, in man-o’-war birds, 795.
of penguins, 347, 357, 358, 383, 384; of alba-
trosses, 568; of petrels, 621, 633; of diving
petrels, 780, 781; of cormorants, 918; of
oyster-catchers, 978, 982, 992; of sheath-
bills, 1005; of gulls, 1063; of young terns,
1108.
Synchronous behavior of flocks, 845, 967, 1146.
Synonymy, of whale-birds, 612.
Syrinx, of boobies, 834, 843, 850, 858.
Systematic relationships, in genus Spheniscus,
455, 456.
INDEX
a
Tablazos, 311.
Tachyeres brachypterus, 199, 208, 954, 955, 964.
patachonicus, 199, 208, 954, 955, 968.
pteneres, 199, 954, 955, 957.
Taczanowski, Ladislaus, 266.
Tagus cove, 32.
Tahiti, 88.
Tail, function of in flight, in Procellariiformes,
485.
variability of, among albatrosses, 491.
use of, during courtship by tropic-birds, 797.
mechanism of, in man-o’-war birds, 925, 926.
Taitao, peninsula of, 244, 246.
Talara, 28, 29, 276, 283, 284, 285.
Talcaguano, 10, 46, 253, 254.
Talral, 10, 265.
Tambo de Mora, 274.
Tambo valley, 271.
Taming, of man-o’-war birds, 934, 935; of
young noddies, 1157.
Tarapaca, 266, 267, 286.
Tarapande, Mar de, 162.
Tarn, mount, 238.
Tate, G. H. H., Venezuelan work, 31, 119, 120.
Tattler, wandering, 275, 312.
Taxonomy of sea birds, important of, 324; mal-
practice in treatment of, 324, 325.
Taylor, Dorothy, 34.
Taylor, W. J., 124.
Teal, Bahaman, 188.
blue-winged, 303.
cinnamon, 188.
South Georgian, biography, 948-951.
yellow-billed, 188.
Tembleque I., 30.
Temperamental responses of birds (boldness,
shyness, etc.), as an intrinsic trait or as
correlated with successive stages of the life
cycle: of Galapagos birds, 302, 982; change
in, due to new external stimuli, 1027; inter-
specific differences among penguins, 449;
responses at different physiological stages,
among penguins, 374, 382, 404, 433, 450;
among albatrosses, 528, 531, 552, 555; of
sete 592, 637, 680; of pelicans, 816; of
oobies, 850, 858; of cormorants, 888, 891;
of man-o'-war birds, 934; of steamer ducks,
967; of skuas, 1026, 1027; of terns, 1096,
1112, 1115, 1116, 1128, 1134, 1135, 1149,
1156, 1157, 1164, 1167, 1196.
Temperature, atmospheric, anomalous se-
quence, north to south, at Peruvian guano
islands, 96; in northern Venezuela, 118; at
Venezuelan coastal islands, 123; at Santos,
163; at Porto Alegre, 163; at St. Helena,
178; in La Plata region, 183; in Argentina,
192; at Falkland Is., 205, 206; at Gough
I., 211; at South Georgia, 221; at South
Sandwich Is., 224; at South Orkneys, 226;
at South Shetlands, 229; in Antarctic
Archipelago, 230; at Staten I., 235; at
1241
Chiloé I., 248, 249, 254; at Juan Fernandez
Is., 255; along desert west coast, 263, 264,
267, 268; at Callao, 279; in Guayaquil
district, 282; at Galapagos Is., 298, 299;
at Tristan da Cunha, 1151; at Dry Tortugas,
1155.
Temperature, effect of slight variations in,
upon human beings, 138, 161.
of brooks at Tristan da Cunha, 217.
Temperature of surface water, in relation to
distribution of life, 60.
in correlation with distribution, of penguins,
342, 343, 364, 387, 412; of tropic-birds, 796;
of pelicans, 820; of boobies, 827; of terns,
1149.
in correlation with abundance of life, 63, 64.
in different life zones, 68-78.
in relation to longevity of marine organisms,
64.
in Sdo Sebastiao current, 161; at Gough I.,
211; in Magellanic channels, 240; around
San Felix and San Ambrosio Is., 259; along
west coast of South America, 267, 283, 284,
285, 311, 314, 321; around Galapagos Is.,
296, 297.
Temperature tolerance, of penguins, 401, 458,
461; of cormorants, 890; of sheath-bills,
1005; of noddies, 1151.
Temuco, 31.
Tenacity of young, in clinging to nest, of man-
o'-war birds, 935, 936; of fairy terns, 1167.
Tern, antarctic, 233, 1104; biography, 1105-
1109; 1113.
arctic, 11, 79, 108; biography, 1099-1105;
1107, 1113.
Atlantic fairy, biography, 1164-1168.
black, biography, 1089.
bridled, 123; Hoendply, 1118.
Cabot’s, biography, 1142-1143.
Caspian, 1094.
Cassin’s, 15.
Cayenne, biography, 1140-1141.
Cocos fairy, biography, 1168-1169.
common, biography, 1098-1099.
elegant, bioetrny. 1141-1142. :
fairy, 79, 149, 153, 179, 313, 318, 320; nesting
habits of, 175; 1094, 1128, 1133, 1134;
biography, 1136-1138; 1149, 1154, 1163.
gull-billed, 137; biography, 1092-1094.
inca, 272, 277, 291, 292, 1139; biography,
1143-1146.
large-billed, 120, 167; biography, 1090-1091;
1133:
least, 120, 123; biography, 1136-1138.
Peruvian, biography, 1134-1136.
roseate, 123; biography, 1116-1118.
royal, 99, 102, 281, 285, 304, 307, 316, 1093;
biography, 1138-1140; 1142.
sooty, 55, 58, 99, 122, 123, 145, 147, 153, 158,
175, 176, 261, 262, 272, 302, 1120; biog-
raphy, 1120-1132; 1143, 1149, 1152, 1154,
1155, 1157, 1158, 1167.
1242
South American, 74, 99, 250, 272; biography,
1094-1097.
South Georgian, 1108; biography, 1109-1113.
South Shetland, 1108.
Tristan da Cunha, biography, 1113-1114.
Trudeau's, biography, 1114-1116; 1134, 1139.
yellow-billed, biography, 1132-1134.
Tern eggs, as food of Yahgan Indians, 15.
Ternlet, gray, 260, 262.
San Ambrosio gray, biography, 1148-1149.
blue, 1147.
Ternlets, Pacific, general account, 1147.
Terns, fairy, general account, 1164.
Terral, 117, 254, 268.
Terrestrial, adaptations, of albatrosses, 567.
proclivities, of Wilson's phalarope, 999.
Territory, its influence and significance in the
life history of penguins, 348, 392, 395, 421,
422, 428, 433, 436; of albatrosses, 552,
573; of petrels, 636, 637, 680, 707; of tropic-
birds, 800; of pelicans, 825; of boobies,
852, 857; of steamer ducks, 962, 966; of
oyster-catchers, 978, 991; of terns, 1097,
1108, 1109, 1128, 1149, 1155.
multiple use of, by Procellariiformes of dif-
ferent size range, 477.
‘Terror,’ 173, 193.
Tessan, U. de, 268, 297.
Testigos Is., 122, 123, 124.
Thalasseus, 1043.
eurygnatha, 80, 81, 122, 124, 167, 168, 1140.
maximus, 99, 102, 122, 124.
maximus maximus, 1138.
sandvicensis acuflavidus, 1142.
sandvicensis sandvicensis, 1143.
Thalassoica antarctica, 71, 227, 231, 232, 638.
Thamnoseris, 260.
Thayer, G. H., 32.
Thayer, J. E., 315.
Theft, of eggs, by penguins, 436.
of nesting material, among penguins, 393,
405, 423, 459; among pelicans, 825; among
cormorants, 889, 890, 894; among man-o’-
war birds, 931, 932; among terns, 1155.
Theristicus, 243.
Thermal economy, Bergmann’s principle of, 358.
Thinocorus rumicivorus, 188, 202.
Thomson, C. W., 216, 217.
Thule I., 224, 225.
Thunderstorms, 78, 94, 106,119,183,298, 314,315.
Tiburén, cape, 110.
Ticks, of albatrosses, 571; of shags, 888.
Tidal rhythm, in relation to feeding and dis-
tribution, of kelp goose, 943; of steamer
ducks, 199, 960, 972; of gulls, 1070.
Tide, on Atlantic coast of Patagonia, 16, 17,
20, 191, 194, 195, 196, 198, 199; in Gulf of
Cariaco, 119; in and near the Amazon, 135;
highest in world at Puerto Gallegos, 237;
at Chiloé I., 248; along west coast of South
America, 273, 280, 281, 282, 285, 306, 307,
316, 317:
INDEX
Tiempo de lomas, 264.
Tierra del Fuego, 16, 31, 38, 48, 49, 50, 69, 70,
73, 75, 92, 109, 169, 192, 193, 201, 204, 218,
220, 235-249.
Tillandsia latifolia, 278.
Timbales I., 13, 16.
“Tinkers,’’ 287.
Tique, 251, 263.
Tirda, punta, 250.
Titicaca, lake, 110.
Toba I., 194.
Tobago I., 23, 123, 124, 144.
Tobogganing, of penguins, 383, 390, 391, 436.
Tocantins, river, 138.
Toco, pampa del, 265.
Tocopilla, 265.
Todd, W. E. C., 35, 113, 114, 120.
Tolerance, range of among birds, to tempera-
ture, humidity, altitude, and other en-
vironmental stimuli, 336; in penguins, 445,
446; of bigiia cormorant, 110; among cor-
morants, 879, 910; in boobies, 835; of
black oyster-catchers, 990; of kelp gull,
1062.
Tombo point, 193.
Tongoi, bay of, 254.
Tongue, of penguins, 375.
Topography, coastal, in correlation with South
American life zones, 164.
Torres Is., 169.
Tortuga I., 37, 122.
Tower I., 32, 299, 300.
Towering, phenomenon of flight, of alba-
trosses and petrels, 500, 570, 571, 593.
Townsend, C. H., 320.
Trachinotus paloma, 1056.
Trade winds, 40, 41, 43, 45, 46, 51, 95, 141,
297; meteorological régime of, 112; ex-
tension and retraction of borders of, 117;
deflection of by continental coasts, 117;
at St. Helena, 178.
Trade-wind drought, 40, 41, 141, 161, 298.
Transportation, of own eggs, by nesting oyster-
catchers, 978.
of birds by sailors, in relation to extralimital
records, 604.
of plants by boobies, 856.
Trapiche I., 321.
“Travesia,’’ 254.
Tree ferns, 174, 215, 256, 318.
Tree-nesting, of brown pelican, 813, 814; of
red-footed booby, 865; of bigiia cormo-
rants, 914, 915; of noddies, 1162; of fairy
terns, 1167.
Trees, killing of by boobies, 867.
Trefusis bay, 13.
Tres Cruces, 274.
Tres Montes, peninsula of, 244, 245.
Tres Puntas, cape, 195.
Tring Zoological Museum, 33.
Tringa flavipes, 187.
melanoleuca, 187.
INDEX
Trinidad, 30, 37, 55, 58, 113, 114, 115, 118, 119,
120, 123, 124, 130, 144.
Tristan da Cunha Is., 72, 73, 75; 80, 81, 92, 109,
154, 155, 175, 200, 203, 208, 210, 211, 214,
218.
Triste, gulf of, 113, 115.
Tropic-bird, Caribbean red-billed, biography,
798-802.
red-billed, 99, 102, 180, 309, 314.
South Atlantic red-billed, biography, 797.
white, 285.
white-tailed, 58; biography, 802-807.
Tropic-birds, general account, 796-797.
Tropical convergence, 77, 79, 1147.
gap, between northern- and southern-hemi-
sphere ranges of migrant petrels, 668, 669.
littoral, characteristics of, 112, 113, 118, 136,
137.
bird life of, 120, 127, 128, 132, 137.
zone, 65, 78, 80, 88, 830.
Trujillana channel, 273.
Trujillo, 96.
Trumajo, 250.
Tryngites subruficollis, 188.
Tschudi, J. J. von, 254, 289, 290, 291.
Tuberculosis, avian, 903.
Tumaco I., 313, 314, 315.
Tumbes, peninsula de, 253.
Tumbez, 264, 291, 303, 307.
Tumbez, river, 282, 307.
Turdus falcklandii magellanicus, 257.
magellanicus, 241.
Turk’s Cap bay, 180.
Turnstone, ruddy, 140, 275.
Turtles, as man-o'-war bird food, 926, 934.
Turumiquire, mount, 31, 119.
Tussac I., 22.
Tutoya bay, 139.
Tylosurus stolzmanni, 827.
Type locality, of Diomedea chrysostoma, 516;
of Markham's storm petrel, 741; of red-
footed booby, 862, 863; of red-footed cor-
morant, 874; of Atlantic fairy tern, 1166.
‘Ucayali,’ 316.
Ugly duckling complex, 340.
Ulloa, Antonio de, 286.
Ultima Esperanza, 31, 38.
United States Biological Survey, 275.
United States National Museum, 33.
United States Weather Bureau, 53, 56.
Uplift, coastal, in southeastern Brazil, 160.
Upwelling, 88, 93, 95, 96, 99, 161, 267, 268, 269,
279, 284.
effect of, upon distribution of birds, 598, 603,
668, 799.
Urabi, gulf of, 110, 111, 112, 113, 114, 115, 120,
316.
Uria, 293.
Uric acid, colloidal suspension of, 337, 338.
1243
Urine, excretion of, 337.
Usborne, Mt., 203.
Ushuaia, 14, 16, 17, 18, 19, 48, 93, 191, 192, 239.
Usnea, 174, 221, 227.
Valdez creek, 191.
Valdez, peninsula of, 190, 192, 193.
Valdivia, 11, 49, 250.
‘Valdivia,’ 233, 234.
Valette, L. H., 227.
‘Valhalla,’ 151, 242.
Vallaux, Camille, 66, 89, 97, 319.
Vallentin, Rupert, 193.
Valparaiso, 10, 11, 31, 49, 249, 253, 254, 263.
Variability, range of, statistically considered,
787, 1008, 1009.
Variation, individual, its extent, in petrels,
642, 643, 669, 787; in cormorants, 910; in
oyster-catchers, 977, 987; in skuas, 1007,
1009, 1010, 1014, 1021, 1024, 1025; in
gulls, 1045, 1060, 1061.
Vauverland I., 15.
Vegetation, insular, as determining the breed-
ing range of the red-footed booby, 174,
829, 865.
Vendevales, 114.
Venezuela, gulf of, 113, 115, 116.
Venezuelan coastal islands, 120, 121; sea birds
of, 122; vegetation of, 118, 121, 122; guano
deposits at, 124.
Ventana, sierra de la, 189.
Venturi, S., 235.
“Vénus,’ 97, 267, 296.
Verano (verao), 40, 41, 140, 303.
Verde I., 189.
Verrill, G. E., 210, 211, 275.
Vertical circulation, 61, 66.
Viability, of penguins in captivity, 466; of
Pelecaniformes, 795; of gulls, 1057, 1069.
Vichuquen, 253.
Vieja I., 272, 277, 278.
Virazon, 268.
Vireosylva gracilirostris, 148.
Virjenes, cape, 17, 18.
Visibility, low, of petrels at sea, 626, 752.
Vision, bifocal, lack of in penguins of the genus
Spheniscus, 439.
Vitality, of penguins, 358, 454; of steamer
ducks, 960, 969; of oyster-catchers, 984; of
skuas, 1025, 1034.
Viveros I., 321.
Vivian, R. A., 56.
Vogt, William, 50.
Voice, of penguins, 353, 360, 365, 374, 375, 396,
397, 407, 424, 426, 427, 428, 429, 434, 436,
439, 458, 465, 470; of albatrosses, 498, 503,
508, 522, 535, 537, 552, 553, 554, 565, 566;
of petrels, 590, 593, 617, 626, 628, 629, 632,
633, 635, 636, 637, 642, 645, 647, 659, 660,
670, 672, 676, 679, 687, 688, 692, 695, 699,
701, 706, 707, 710, 713, 725, 729, 737, 738;
1244
of storm petrels, 746, 748, 753, 754, 767,
769, 770; of diving petrels, 775, 777, 790;
of tropic-birds, 799, 800, 806, 807; of peli-
cans, 815, 824; of boobies, 841, 843, 853,
857, 858, 868; of cormorants, 874, 876,
887, 894, 906, 908, 918, 919; of man-o'-war
birds, 932, 936; of steamer ducks, 962, 967,
968; of oyster-catchers, 977, 980, 982, 985,
986, 991, 992; of sheath-bills, 1005; of
skuas, 1020, 1025, 1028, 1029, 1032; of
gulls, 1046, 1048, 1057, 1066, 1068, 1069,
1076, 1085; of terns, 1091, 1109, 1112, 1113,
1116, 1120, 1122, 1124, 1126, 1128, 1130,
1135, 1136, 1139, 1146, 1156, 1157, 1163,
1168; of skimmers, 1175, 1176, 1178.
Volcanic character of, South Trinidad, 173; St.
Helena, 177; Deception I., 228; South
Sandwich Is., 224; Bouvet I., 234; Juan
Fernandez, 255; San Felix and San Am-
brosio, 259, 260; Galapagos Is., 300; Cocos
Te Sl7Pearl Ise o21-
Vultur gryphus, 190.
Vulture, black, 112, 137, 281.
turkey, 112, 207, 241, 245, 276, 281, 312,
1145, 1146; as enemy of boobies, 837.
Wafer bay, 317.
“Wager, 244.
Waini, 132.
Walcott, F. C., 30.
Wallace, A. R., 136.
Wandering, post-nuptial, of tropic-bird, 803,
804.
Washing reaction, of penguins, 424, 430, 437,
462; of petrels, 609; of cormorants, 907;
of skuas, 1029.
Washington, H. S., 259.
Washington channel, 19.
‘Wasp,’ 223.
Water, metabolic, 337.
Water hemisphere, 65.
Waterman I., 243.
Waterton, Charles, 133, 134.
Watjen, Paula (Mrs. J. S. Rockefeller), 34.
Wave-erosion, at Gough I., 210.
Wear and fading, effect of upon plumage of
various birds, 586, 600, 606, 607, 648, 704,
721, 763, 765, 783, 1019, 1025.
Weather, in Fuegian region, 15, 17, 19, 20, 21.
Webster, F. B., 4.
Weddell sea, 69, 73, 93, 224, 229, 230, 233, 330,
389; effect of its ice upon South Atlantic
temperatures, 543.
Weight, of penguins, 353, 354, 358, 366; of
albatrosses, 532, 541-543, 566, 583; of
pelicans, 820; of boobies, 833; of flightless
cormorant, 917; of man-o'-war birds, 924,
925, 930; of steamer ducks, 956, 959, 970.
Wenman I., 299, 300.
Wert, Sebald de, 74.
INDEX
West Antarctica, 32, 66, 76, 93, 109, 229, 230.
West Falkland, 22.
West Point I., 22, 204.
“West Quechee,’ S. S., 54.
West wind drift, oceanographic effect of in
South Atlantic, 543.
Westerlies, 48, 49, 50, 94, 191, 192, 204, 444;
character of, in Patagonia, 237; in Fuegia,
238, 240, 244.
Wetmore, Alexander, 5, 35, 170, 188.
Wetzel, W., 265, 267.
Whale, humpback, 1146.
killer, 365, 400.
Whaleback ridge, 159.
Whaleboat sound, 13.
Whale-bird, antarctic, biography, 620-629.
broad-billed, biography, 615-620.
slender-billed, biography, 629-631.
Whale-birds, general account, 610-615; as food,
617.
Whales, depths at which they can feed, 97,
315; as attraction to birds, 663; followed
by petrels, 759.
Whaling, antarctic, effect of, upon food re-
sources and distribution of birds, 93, 194,
228, 229, 231, 318, 487, 600, 601; as affect-
ing albatrosses, 545, 563; petrels, 590, 596,
635, 644, 753, 754; skuas, 1018; gulls, 1069.
Whirr-flight, of diving petrels, 484, 771.
White, E. W., 183.
Whitlock, F. L., 50.
Whitman, Walt, 91.
Whitney, H. P., 2, 6.
Whitney South Sea expedition, 3, 326.
Wickham heights, 203.
Wideawake Fair, 153, 1125, 1126, 1127.
Wild, Frank, 150.
Wilkins, Sir Hubert, 210, 211, 214, 216, 217,
224, 229.
William, port, 21.
Willis, Bailey, 259, 260.
Wilton, D. W., 213.
Wind, direct relation of, to breeding sites of
birds, 390, 774; to albatross flight, 566,
567, 569, 570, 582; to the return to burrows
of petrels, 679, 681.
Windward coasts, predilection for, of alba-
trosses, 550, 566, 574.
Windward feeding habit of petrels, 660; of
diving petrels, 776.
Wing-beat, rate of, in cormorants, boobies,
pelicans, and gulls, 876; in oyster-catchers,
982; relative, in skuas, 1028; in gulls,
1076, 1085; alternate, in steamer ducks,
959, 966.
Wing form, as correlated with habits, of cor-
morants, 896.
Wing-spread, of Galapagos albatross, 532; of
wandering albatross, 541-543; of royal
albatross, 582, 583.
Wings, weakness of, in young penguins, 385.
INDEX
Winter-breeding of certain petrels, 684, 759; of
terns, 1043.
Winter range, of penguins, 403, 404, 443; of
phalaropes, 995, 996, 997, 998.
Wintering in Antarctica, of sheath-bills, 1001.
Wire-bird, 179.
Witte, Helen F., 34.
Wollaston, A. F. R., 115.
Wollaston I., 15, 241.
Wood ibis, 137, 166.
Yahgan Indians, 15.
Yates, Captain, 247.
Young, C. Z., 132.
Yucatan, 117.
Yuramangui, rio, 314.
Fa
*‘Zaca,’ Pacific cruise of, 31, 32; 256, 260, 261,
276, 277, 705, 718.
Zanthoxylum, 257.
1245
Zavodovski I., 225.
Zenaida auriculata noronha, 148.
Zonal affinities, of penguins, 410, 411, 433, 434;
of albatrosses, 490, 495, 496, 502, 510,
520, 521; of giant fulmar, 589; of cape
pigeon, 603, 604, 605; of shoemaker, 643,
644; of petrels, 691, 701, 706, 709, 714,
717, 724, 725, 745; of diving petrels, 772,
785; of tropic-birds, 801, 804; of boobies,
830, 831, 855; of cormorants, 878, 879,
880, 881; of man-o’-war birds, 929; of
South American geese and ducks, 941; of
gulls, 1044, 1059.
Zonal correlations, of Pachyptila, 612.
Zonal distribution, of albatrosses, variation of
due to latitude, 547; of whale-birds, 623.
Zonda, 183.
Zoneless birds, 76, 108-110.
Zodgeographic réle, of South American tern
and of kelp gull, 1096.
Zorell, Franz, 95.
Zorritos, 304.
Fairy Terns and Black Noddies, South
Trinidad Island.
Pediunkers, or Gray Petrels, at the nest burrow,
Nightingale Island, Tristan da Cunha.
Peru.
Peruvian Pelicans, Ancén,
ee, eke a Pas
Blue-footed Boobies in courtship performance, Lobos de
Tierra Island, Peru. Turkey Vulture in flight.
Piqueros, or Peruvian Boobies, Pescadores
Island, Peru.
ge by oe
LF ¥.
eieaets wg Sue
ott Pry. a Ste. er Be
» ros
Guanays, or Peruvian Cormorants,
Santa Rosa Island, Peru.
Fuegian Oyster-catchers, Falkland Sound.
~ Gray Gulls, Ancén, Peru.
Belcher’s Gull (with banded tail) and Kelp Gull, Santa
Rosa Island, Peru. The other birds are Peruvian Boobies.
Red-footed Cormorants and Inca Terns,
coast of Peru,
PA ess
PLATE 39
D. S. Bullock
Nest burrows of the Pink-footed Shearwater, in the forest of Mocha Island,
about 250 meters above sea level. November, 1932.
R. C. Murphy
A Shoemaker at the entrance of its burrow. South Georgia, November, 1912.
Prate 40
R. H. Beck
Kermadec Petrels, light and dark phases, at their nests. Mas Atierra Island,
December, 1913, and January, 1914.
R. C. Murphy
Fledgling Peruvian Diving Petrel, after removal from its burrow.
Vieja Island, November, 1919.
R. H. Beck
Falkland Diving Petrel, after excavation of its nest within the base of a hummock.
Kidney Island, November, 1915.
Puate 42
Fahnestock Expedition
Incubating Caribbean Man-o'-war Birds of both sexes. Pearl Islands, January, 1935.
J. P. Chapin
Red-billed Tropic-bird on its egg. Daphne Island, Galapagos, April, 1930.
Prate 43
J.P. Chapin
Fahnestock Expedition
Brown Pelicans at the Pearl Islands. Upper, April, 1930; lower, January, 1935.
PLATE 44
J. P. Chapin
Peruvian Pelicans. Chincha Islands, February, 1935.
J. P. Chapin
Incubating female Ridgway’s Man-o’-war Bird. Tower Island, Galapagos, April, 1935.
Prater 45
R. C. Murphy
Male (left) and female Blue-footed Boobies. A mated pair, photographed simultaneously
at Lobos de Tierra Island, to show the characteristic sexual dimorphism in the eye.
Van Campen Heilner
The author interviewing a Blue-footed Booby at El Muerto Island.
Prate 46
ee
R. C. Murphy
Piqueros. Upper: A ledge of the Amphitheatre, north Chincha Island. Lower: Parent and
young, south Guafiape Island. November, 1919, and January, 1920, respectively.
Van Campen Heilner
J. P. Chapin
The characteristic ring of guano. San Felix Island, February, 1935.
PACIFIC MASKED BOOBY
Piare 48
F. M. Chapman
Male Colombian Booby, showing the gray head which distinguishes it from the
Atlantic race. Pearl Islands, March, 1931.
F. M. Chapman
Brown Booby beside its nest. Cay Verde, Bahama Islands, March, 1917.
PLatTe 49
R. H. Rockwell R. C. Murphy
Adult in white phase, and immature. South Trinidad Island.
J. P. Chapin
Nesting adult, gray phase. Tower Island, Galapagos, March, 1935.
RED-FOOTED BOOBY
Piare 50
Kydan DW
‘TI6L ‘sequiacaq ‘says] Jo Aeg *as9u parafdusooun uv uo drysimoo ux s8eyg pada-onig urIs10a4) YINOS
R. C. Murphy
Naked chicks, one and two days old, respectively, of the South Georgian Blue-eyed
Shag, December 24, 1912; and below, the same chicks as seven-week fledglings, on February
16, 1913. Bay of Isles, South Georgia.
PLATE 52
R. C. Murphy
Young Guanay, which voluntarily came aboard a launch off northern Peru. The photo-
graph shows well the length and robustness of the wing in this strong-flying cormorant.
R. C. Murphy
Brooding female South Georgian Blue-eyed Shag. Bay ot Isles, December, 1912.
Puate 53
R. H. Beck
Bleaker Island, Falklands, December, 1915.
A King Shag colony.
Piate 54
“CIOL ‘Joquiacaq, ‘spuryyAley ‘purysy isvq “Auoyoo seyg yoy V
PLATE 55
R. C. Murphy
Glimpses of a Guanay colony, Pescadores Island, December, 1919. New eggs have been
laid in nests recently deserted by fledglings of an earlier generation.
PLatTe 56
R. C. Murphy J. P. Chapin
Roosting on the wreck of the ‘Leonidas.’ Nesting in the rigging of a hulk.
Chincha Islands, November, 1919. Coquimbo, Chile, February, 1935.
BIGUA CORMORANTS
aa
W. K. Gregory 7 J. P. Chapin
Flightless Cormorants. Tagus Cove, Albemarle Island, Galapagos.
PLATE 57
“(47024 sould vyPTad7 )
“CI6L ‘Jaquiacaq “spur[y[ey ¥
Pilg JVM- O-ULY peprulry, YINog aya Jo Sunod pur ayvura.y ‘pur[s] Jaxva[g “[visJaIvul isau FO [[NFI[Iq v YIM Seyg sury
IP™20" "HU
— erry ae
yoo “HU
cea xa >: an
PraTE 58
:
J. P. Chapin
Soaring above the yacht ‘Nourmahal.’
J. P. Chapin
A courting male, with inflated pouch.
RIDGWAY’S MAN-O’-WAR BIRD. TOWER ISLAND, GALAPAGOS, APRIL, 1930
Piate 59
R. H. Beck
R. H. Beck
Nest of Magellanic Kelp Goose. Thomas Island, December, 1914.
R. C. Murphy
A pair of South Georgian Teals, with the drake in the foreground.
Bay of Isles, December, 1912.
R. H. Beck
Magellanic Flightless Steamer Ducks. Hermite Island, December, 1914
Prate 61
R. H. Beck
Punta Loyola, Atlantic coast of Patagonia, in midwinter. August, 1915.
R. H. Beck
Among King Shags and Rockhopper Penguins. Bleaker Island,
Falklands, December, 1915.
SHEATH-BILLS
PLatE 62
“ST6T ‘soquiacaq ‘spurpyley “purlsy AVI] “s[]Iq-yavays
PLATE 63
co neem
ee.)
R. C. Murphy
R. H, Beck
Nest and eggs of the Chilean Skua. Caroline Island, December, 1914.
PLATE 64
kydin-w *O -Y
“CT6r ‘Asvnurf[ ‘utds1095 YInog ‘saysy JO Avg “wivosis [vrs v UT SupsvsoF senyg UMOIg
“CI6T ‘laquiasaq ‘spuryyxyey “Ppury[s] Voy vag ‘summSuag Wurasryy puv “sj[ns) pepooy-uMmorg ‘sng urydjoq
oa “HY
PLATE 65
PLATE 66
F. M. Chapman J. P. Chapin
Kelp Gull on the superstructure of Dusky Gulls, Conway Bay, Indefatigable
a steamer. Coast of Peru. Island, Galapagos.
_—
--
lla
J. P. Chapin
Dusky Gulls, near the anchorage of the ‘Nourmahal.’ Darwin Bay,
Tower Island, Galapagos, April, 1930.
PLATE 67
yg “HY
“PI6L ‘ZZ JOqUIBAON “UrT[asKYY JO IeIIg O42 UT Ysy Fo [voYs v Surmoy[oy s[[ND day
PLatTe 68
= ae Sf .
Fahnestock Expedition J. P. Chapin
Laughing Gull. Panama, January, 1935. Mountain Gull. Pisco Bay, February, 1935.
J.P. Chapin
The twelve smaller birds in the foreground are apparently Gray-hooded Gulls (Larus
cirrocephalus), a species of uncertain status on the coast of Peru. The other two are either
Belcher’s or Kelp Gulls. Pisco Bay, February, 1935.
Prate 69
Toshio Asaeda
J. P. Chapin Toshio Asaeda
Swallow-tailed Gulls. Darwin Bay, Tower Island, Galapagos, March, 1935.
PLATE 70
R. C. Murphy
South Georgian Tern, and its single egg. Bay of Isles, January, 1913.
we
R. H. Beck R. H. Rockwell
Inca Tern in its nest crevice. San Gallan Sooty Tern and Brown Noddy. South
Island, July, 1914. Trinidad Island, January, 1925.
PiatEe 71
J. P. Chapin
: R. C. Murphy
Inca Terns at the Chincha Islands. Upper: February, 1935; lower, October, 1919.
Pirate 72
. Toshio Asaeda
Pacific Fairy Tern, to illustrate the translucence of the wings.
Ducie Island, southern Polynesia.
R. H. Rockwell
Atlantic Fairy Tern and chick. South Trinidad Island, January, 1925.
~
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