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Plate I. Cahow. Painting by Roger Peterson, by kind permission of the artist and 

the American Ornithologists' Union 



«,* H* Oce,no8r,P«e »«»« tJV 



SEA-BIRDS 

An Introduction to the 

Natural History of the Sea-Birds of 

the North Atlantic 

by 

JAMES FISHER 

and 

R. M. LOCKLET 



WITH 9 COLOUR PHOTOGRAPHS 

68 BLACK AND WHITE PHOTOGRAPHS 

AND 66 MAPS AND DIAGRAMS 



/^ 



MBL / WHOI 
LIBRARY "^ 

Woods Hofe, MA 

Marine Biological Laboratory 
VWaods Hofe Oceanographic 



OFFICE OF THc 
LARCH LIBRARIAN 



Institution 



1954 
HOUGHTON MIFFLIN COMPANY, BOSTON 

The Riverside Press, Cambridge 



First published in the United States 1954 



To 
JULIAN HUXLET 

in gratitude for his guidance 

and encouragement, and in recollection of the 

many happy days we have spent together, 

watching sea-birds 



Printed in Great Britain by 
Willmer Brothers & Co. Ltd., Birkenhead 
for Collins Clear-Type Press, London and Glasgow 



ERRATA 



as far south as Cook Strait, 
p. 206. Caption Fig. 36, for Red-cormorant, read Rced- 

cormorant 
PI. XXXI VA, opp. p. 261, for Tern, read Terns 



CONTENTS 

PAGE 

Publisher's Xote ix 

Authors' Preface xi 

CHAPTER 

I The North Atlantic Ocean : Its Structure and its 

I 

31 
56 

p. 5, line 22, should read: (Sec Fig. 54, p. 290.) • 1 10 

p. 132, line 4, for Lams, read Larus ^ 
Pi. XIV, opp. p. 133, transpose captions of a and h 

p. 161. Caption Fig. 29, last line should read: and P.p. gavia \ c'7 

165 
178 

222 
227 

13 The Auks 267 

Appendix : List of Sea-Birds of the North Atlantic 

AND their Distribution 292 

Bibliography 297 

Index to Vertebrate Species 313 

Index to Authorities 319 



PLATES IN COLOUR 

1 Gahow. Painting by Roger Peterson frontispiece 

2 Storm-petrel incubating in rock crevice facing page i6 

3 Cormorant colony 1 1 7 

4 Great blackback at nest 124 
5a Roseate tern 245 
5^ Sandwich tern , 245 
6a Little tern on eggs 252 
6^ Black tern on eggs 252 

7 Razorbills 277 

8 Puffins sunning on a breeding-slope 284 



PLATES IiN BLACK AND WHITE 

I Rockall facing page 52 

iia Eldey, a last refuge of the great auk; and gannets 53 

lib Elegug Stack; guillemots, razorbills and kittiwakes 53 

III Dry Tortugas ; sooty terns 60 

IV Double-crested cormorant, nesting in trees 61 
va Grassholm gannetry 84 
vb Bonaventure gannetry 84 

VI Brown pelican 85 

VII Shags and kittiwakes 92 
VIII Dune-dwelling Sandwich terns 93 

IX Guillemot cliff in Shetland 96 

vi 



PLATES IN BLACK AND WHITE 

xa Fulmars and great shearwater, Rockall facing page 97 

x^ Manx shearwaters off Skokholm gy 

xia Leach's petrel 112 

xi^ Madeiran petrel 112 

xiifl North Atlantic shearwater 113 

xii^ Manx shearwater 1 1 3 

xiiifl Bulwer's petrel 132 

xiii3 Bulwer's petrel, day-old chick 132 

xivfl Deserted young fulmar 133 

xiv3 Deserted young Manx shearwater 133 

xvfl Brown booby 140 

XV Z> Blue-faced boobies 140 

xvifl Display of mated gannets 141 

xviZ> The feeding process in the gannetry 141 

xviia Gannet landing 196 

xvii3 Gannet taking flight 196 

xviiia Gannet with stolen grass 197 

xviii^ Gannet about ten days old 197 

xviiid: Immature gannet about to leave nest 197 

XIX Man-o'-war birds 204 

XX(3 Dark phase of arctic skua 205 

xx^ Light phase of arctic skua 205 

xxifl Light phase arctic skua in flight 208 

xxi3 New-born chicks of arctic skua 208 

xxim Display of great skua 209 

xxii^ Great skua stooping at camera-man 209 

xxiii Laughing gulls 224 

xxivfl Herring-gull at nest 225 

xxiv/> Lesser black-backed gull 225 

XXV Ring-billed gulls 228 

xxvi<2 Immature Iceland gull, winter 229 

xxvi^ Adult Iceland gull, summer plumage 229 

vii 



PLATES IN BLACK AND WHITE 

xxviifl Immature glaucous gull ' 236 

xxvii^ Immature Bonaparte's gull 236 

xxviii^ Little gull 237 

xxviii^ Chicks of yellow-legged herring-gull 237 

xxixfl Laughing gulls 240 

xxix^ Black-headed gulls 240 

xxxfl Offal-scavenging gulls at fish wharf 241 

xxxb Sabine's gull, winter 241 

xxxc Black-headed gull, winter 241 

xxxia Common gulls, summer 256 

xxxib Eggs of gull-billed tern 256 

XXXII Royal terns over nesting colony 257 

xxxiHfl Little tern 260 

xxxiii3 Black tern, autumn 260 

xxxiva Common terns mating 261 

xxxiv^ Caspian tern 261 

XXXV Noddy 268 

xxxvifl Black skimmer and chick 269 

xxxvi^ Gull-billed tern family 269 

xxxviifl Razorbill chick 272 

xxxvii^ Common guillemot chick 272 

xxxviiifl Black guillemot 273 

xxxviii^ Little auks, winter 273 

xxxix Common guillemots ' 288 

XL Briinnich's guillemots 289 



It should be noted that throughout this book plate numbers in arabic 
figures refer to Colour Plates, while roman numerals are used for 

Black-and- White Plates 



vm 



PUBLISHER'S NOTE 

James Fisher is the author of The Fulmar (1952); and R. M. Lockley, 
author of Shearwaters (1949), has just pubhshed Puffins (1953). There 
could, in fact; hardly be any other pair of authors better qualified to 
describe the sea-birds of the North Atlantic than these with their 
experience of many years of field work and visits along the coast 
and islands, from Spitsbergen and Iceland in the cool north, to 
Madeira and the Salvages in the warm south, of that great demi- 
ocean. They have made their visits often together, often separately, 
and lived much on the small remote islands where sea-birds breed. 

The North Atlantic, busiest ocean in the world, is revealed in the 
opening chapters not as a monotonous watery plain, but as an intri- 
cately varied, densely inhabited foraging ground for sea-birds. This 
avian community, though remarkably homogeneous in difierent 
sections of the broad expanse of the North Atlantic, is fascinating in 
the variety of the species that compose it, and in the complexity of their 
movements and migrations. The annual migrations of some species 
extend the total range of the community from the arctic to the antarctic. 
These long transatlantic migrations, verified by ringing, take species 
from east to west between Europe and North America, and from north 
to south between Greenland and South Africa, Britain and South 
America. 

The authors tell us of the primitive progenitors of the sea-birds, 
dating from over sixty million years ago, and the evolutionary adven- 
tures of their descendants, including the notorious extinction of the 
strange flightless great auk, the sad decline of many other fine species, 
also the rediscovery of the cahow after it had been presumed extinct. 
They have paid special attention to geographical distribution, and 
have provided a unique collection of maps, giving us, for the first time, 
the distribution of most species of North Atlantic sea-birds. 

Chief among the authors' interests has been the study of sea-bird 
numbers. They were largely responsible for organising the surveys 
of that splendid and typical North Atlantic animal, the gannet, which 

ix 



PUBLISHER S NOTE 

provided biology with the first reasonably accurate figure for the 
world population of any single and fairly numerous bird species. They 
have, from their own notes and those of many amateur and professional 
bird-watchers, produced interesting statistics of the total population 
of the fulmar, the Manx shearwater, the puffin and many others. 
Incidentally, such careful counts, site by site, reveal the continuous 
change that is going on in sea-bird populations, often directly or 
indirectly due to man's influence. 

The chapters on life-history are preceded by a general account of 
social and sexual behaviour, which throws light upon the significance 
of the prolonged and, to the observer, entertaining, mutual ceremonies 
of these strictly monogamous birds, their pair-formation, their fidelity 
to their mates, their nest-sites and their parental duties; at the same 
time problems of instinct and learning ability are discussed. The life- 
histories include much original field-work by the authors, who have 
been responsible for several discoveries concerning the incubation and 
fl.edging of a number of sea-birds. 

We read of the birds' ecology, their sharing of the wild frontiers 
of the land where they nest, their niches in the economy of the ocean. 
We learn of the contrasts between cliflT-dwelling and hole-nesting 
species, of how the guillemot and razorbill chicks, exposed to many 
dangers on the open rocks, hasten their feather-growth and depart to 
the sea in two weeks, while the young puffins, safe in the darkness of 
their burrows, delay their departue for seven weeks, and are finally 
deserted by their parents ; we learn of the strange lives of the shear- 
waters and small petrels which wander after the breeding season 
between the North and South Atlantic Oceans, living in perpetual 
summer — the Tristan shearwater "wintering" in our northern summer, 
and the Manx shearwater enjoying its "winter" in the southern summer 
off the coasts of South America. 

But we have said enough to indicate the richness of knowledge 
brought together in this volume, which we confidently recommend 
as indispensable to everyone interested in the birds of the sea. 



AUTHORS' PREFACE 

The heroes of our story are rather over a hundred species of birds 
whose life is a sea-Ufe, whose habits enable them to earn at least 
part of their living in, or on, salt water, and which have been seen in 
the Atlantic Ocean north of the Equator. 

The North Atlantic is the scene of our book, the great ocean that 
is now the most travelled by man. Its two sides are provided with an 
almost equal variety of sea-birds: sixty-eight species, or rather over 
half are common to both. Of all Atlantic countries Britain, considering 
its size, has the greatest number of sea-bird species; with no less than 
eighty, it can boast on its list all but six of those that have been seen 
on the Atlantic coast of Europe. The British Isles therefore make a 
good headquarters for a survey of the sea-birds of the North Atlantic. 
In Britain, and from Britain, the writers of this book have explored 
the eastern Atlantic sea-bird stations, and enjoyed many fine islands 
and memorable experiences. One or the other of us has sought the 
sea-birds south to the frigate-petrel burrows of the Salvages, near the 
Canary Islands; north to the ivory-gull colonies on the nunataks 
that rise from the ice-cap of Spitsbergen; or from 30°N. nearly to 
8o°N., a distance of more than three thousand miles; west w^e have 
ranged to Iceland, the Faeroes, Rockall, St. Kilda and the Blaskets 
of the Kerry coast; east we have travelled to Heligoland, and as far 
as Laeso in the Kattegat and Gotland in the Baltic, with their off- 
lying islands of sea-birds. There is no coastal county in England, 
Wales and Scotland that has not been visited by us both, and not 
one in Ireland that has not been visited by one of us. 

No good British sea-bird cliff or island has been overlooked in 
our search for what the naturalist searches for; our experience and 
enjoyment has been long and continuous because both of us are, 
each in his somewhat different way, obsessed with sea-birds and with 
islands. We have spent a combined total of nearly seventy years sea- 
bird watching. 

We have seen the little crags and green island swards of the Isles 
of Scilly and the drowned coast of Cornwall; the granite cliffs and 

xi 



authors' preface 



puffins of Lundy; the chalk of south England east from Dorset; the 
flats and shingles and dunes of Essex and Suffolk and Norfolk, and 
the sanctuaries of Havergate and Minsmere and Walberswick and 
Cley and Blakeney and Salthouse, with terns and avocets and many 
kinds of marsh-birds. One of us has spent many years of his life in 
the county of Pembroke, living on Skokholm, and on other islands 
and peninsulas of the Welsh coast; of its sea-birds he has written 
in many books, and on Skokholm established the first permanent 
coastal bird observatory- in Britain; the other has spent parts of twenty 
seasons in North Wales, and has worked its coast from St. Tudwal's 
Islands to the Little Orme. Both of us know the Yorkshire bird-cliffs 
most of the way from Flamborough Head to Saltburn; and we have 
explored the shore of Durham, where bird-cliffs and black industry 
mix. In Northumberland we know Cullernose Craster, and Dunstan- 
burgh and Bamburgh Castle, and the cliffs north of Berwick, and 
other places where sea-birds nest; and we have been to the Holy 
Island, and to Coquet Isle, and to various of the Fame Islands, where 
the guillemots and kittiwakes are tame. We have seen the steep cliff- 
hill of the south part of the Isle of Man, and the sanctuary of the Calf; 
and have visited the inland gull colonies of North Lancashire and the 
Lakes. 

In Scotland we have, at one time or another, visited every important 
sea-bird station: in the east St. Abb's Head, Fast Castle, Tantallon 
Castle, the Bass Rock, the exciting Isle of May, and many others; 
in the west the Lowland coast from the Mull of Galloway in Wigtown- 
shire up-Clyde as far as Ailsa Craig, whose magnificent gannetry has 
been the scene of many weeks of enjoyment and experiment in efibrts 
to improve the counting of nesting sea-birds. Our visits farther north 
have taken us to Fowlsheugh in Kincardineshire, and round the 
bird-cliffs of the Aberdeen-Banff border — Pennan Head, Troup Head 
and others. West along into the Moray Firth we have hunted out 
the bird-cliffs as far as they go, which is to Covesea in Morayshire. 

In the West Highlands we have explored the mainland promon- 
tories of Kintyre and Ardnamurchan, and the islands of the Clyde 
and Inner Hebrides. We have searched the cliffs of west Islay closely 
from a slow aeroplane. The curious headland of Ceann a 'Mhara on 
the lovely sunny Island of Tiree has been investigated, as have the 
odd-shaped Treshnishs, home of seals, and the capes of Mull. The 
island of Eigg, where the shearwaters nest in a mountain; the magni- 
ficent but somewhat birdless island of Skye, and some of its attendant 



AUTHORS PREFACE 

islets and stacks; both the lonely coast of Ross and its islands — Priest, 
Tanera, Glas Leac Beg and many others, where Frank Darling first 
worked out his theory of bird sociality by studying herring-gulls. 

In the North Highlands we have watched the birds of the Black 
Isle Coast, and those of Easter Ross where the coast continues north 
of the Cromarty Firth to Tarbat Ness. In East Sutherland Dunrobin 
Castle itself becomes a bird-cliff, because fulmars are now prospecting 
it— and there we have seen them ; in West Sutherland we have travelled 
nearly the whole wild coast, in instalments spread over several years; 
we know the crags of Stoer; the Torridonian sandstone precipices of 
Handa, the best bird island in Sutherland; the lonely cliffs on each side 
of remote Sandwood Bay — and Eilean Bulgach opposite which only 
half-a-dozen naturalists have visited; the high promontory of Cape 
Wrath, and the higher cliff of C16 Mor to the east of it — the highest 
mainland cliff in Britain — where the guillemots on two-hundred-foot 
stacks must be observed from six or seven hundred feet above; Fair- 
Aird Head and the home cliffs and caves of Durness ; the huge white 
crags and stacks of Whiten Head ; the complex of islands and cliffs 
that stretches thence to Caithness, whose headlands too, we know, 
and their birds — Holborn Head, Dunnet Head, John o' Groats and 
Duncansby Head, Noss Head, Berriedale Ness. 

In many years, and many boats (as well as from aircraft), we have 
enjoyed the Outer Hebrides, from North Rona (which many call 
the loneliest place to have been inhabited in Britain) to Barra Head. 
We have seen the seals and birds of Rona, and counted the gannets 
of its lonely neighbour Sula Sgeir; and have hunted out the coast 
of the Lewis, and much of Harris. One of us has slept some nights on 
the Shiants, among the rats that may be affecting the population of 
that vast remote puffinry; and has several times threaded the maze 
of the Sound of Harris, and eight times has been to St. Kilda, whose 
unsurpassed cliffs and towering stacks have to be seen to be believed 
(and are sometimes then not believed). We have traversed the Long 
Isle — North Uist, Benbecula, South Uist and Barra — and many of 
its attendant isles, and carried on to sail close under the cliffs of 
Mingulay and Berneray, which for remoteness, grandeur and person- 
ality are rivals — much overlooked rivals — to those mighty precipices 
of St. Kilda, Conachair, Soay and Boreray. 

One hundred and ninety-one miles west of St. Kilda, and about 
three hundred miles from the mainland of Scotland, lies a tiny rock 
which has been a magnet for us both — not only because of its bird- 

xiii 



AUTHORS PREFACE 



problems, but because it is a tiny remote rock! Fisher flew over Rockall 
in 1947. In 1948 Lockley spent twelve days in a trawler fishing 
within sight of, and on occasion very close to it. In 1949 Fisher sailed 
there in H. G. Hasler's sixteen-ton yawl Petula, and spent some time 
investigating it at close quarters. 

One of us has visited Sule Stack, the lonely gannetry thirty miles 
west of Orkney; and we have enjoyed nearly every island, from 
North to South Ronaldsay, from Eynhallow to Hoy, and have seen 
sea-birds in a great range of surroundings. Neither of us is a stranger 
to the well-named Fair Isle, a great migration and sea-bird station. 
We know the Shetland gannetries of Noss and Hermaness, where 
thousands nest — though forty years ago there was none. We have 
stood at the top of Foula's Kame, and gazed twelve hundred and twenty 
feet to the auk-scattered sea below. We have sailed in and out, and 
round about, the stacks and rocks and skerries, and voes and geos 
of straggling Shetland, and seen many a fine cliff, from Sumburgh 
in the south to Saxa Vord in the north; from Noss on east to Papa 
Stour on west. \Ve are no strangers to Fitful Head, or Hillswick, or 
Ronas Voe, or Burra Firth ; or to Hascosay, the bonny isle of Whalsay, 
Fetlar, Bressay or Mousa; or to the Out Skerries, nearest British 
land to Norway. 

Perhaps in Ireland we have not seen all we should; but one of 
us knows the windy corner of Kerry, the end of the world, where the 
pure Irish survives on the Blasket, and where the fulmars now glide 
and play round Inishtearaght, Inish-na-Bro, and Inishvickillaun; 
and where the gannets mass white on the serrated pinnacles of the 
Little Skellig, second gannetry of the world. He knows, too, the little 
gannetry of the Bull, and its neighbour the Cow, and other crags of 
Cork from Cape Clear Island and Dursey Island east to Great New- 
town Head. In Clare the cliffs of Moher bring sea-birds to nest among 
many beautiful flowers. We have seen the bird-colony of the Great 
Saltee in Wexford, and that of Lambay not far from Dublin. One of 
us knows the many fine, high cliffs of Mayo and Sligo, and some 
headlands of the maze-coast of Donegal; the other has watched 
fulmars haunting the curious inland cliffs of Binevenagh in Derry, 
and hunted out the basalt coast of Antrim and the Giant's Causeway. 

Between us, then, we have seen much of the coast of our glorious 
islands; but we have not seen nearly enough, and we hope to see what 
we have already seen, all over again. And we would see the west side 
of the ocean we have grown to love, and compare it with the Britain 



XIV 



authors' preface 



we know, and other sea-bird countries we have seen — the tuff and 
lava and basalt of Iceland, the basalt crags of Faeroe, the dissected 
plateaux of Spitsbergen, the misty cliffs of Bear Island, the drowned 
coast of Norway with snow-coated Lofotens and dark fjords like 
corridors, the friendly limestone of Sweden's Gotland, the skerry- 
guard of Stockholm and Uppland, the dunes of Denmark and the 
Dutch islands, the red sandstone cliffs of Heligoland (the only cliffs 
in western Germany), the chalk and granite of north France, and the 
islets of Brittany; the benign, sunny slopes and little scarp-precipices of 
the Channel Islands where one of us lived for a while; the warm, 
shearwater islands of the Portuguese Berlengas, the Madeiran Desertas, 
and the Salvages; and the gulleries and terneries of the Camargue, 
within the Mediterranean. 

This book is not a comprehensive survey of a problem based upon 
a lifetime's experience nor yet a full bibliographical compilation. 
We have paused in field-work simply to offer this book as a stimulant, 
which we hope very much it will be. We intend it as no more. It is a 
statement of some of the facts concerning the wonderful sea-birds of 
the North Atlantic, and of some of the interesting problems connected 
with their lives and their evolution. It is intended to exhibit the ignor- 
ance of ornithology as much as its knowledge, and to draw attention 
to what needs doing as much as to what has been done. It is our wish, 
we must also add, not only to take the reader with us — if he will come — 
to the east side of the North Atlantic where the sea-birds are more in our 
personal experience, but also to the western seaboard, w^hich is zealously 
worked by the ornithologists of the United States and Canada and 
described by them with such enthusiasm and thoroughness in numerous 
books and journals. One of us has corrected the galley proofs of this 
book in an aircraft bound for North America, on the beginning of a 
journey among the sea-birds of that continent; as he left Britain, 
Ailsa Craig flashed white with gannets in an April evening sun, and 
the first bird he saw in the New World, through Newfoundland clouds 
next morning, was a gannet. 

For help, encouragement and information we have more friends to 
thank than we can mention. Our search of the literature has been 
chiefly pursued in books belonging to the Zoological Society of London, 
the Alexander Library at Oxford, the Royal Geographical Society and 
the London Library, and we thank G. B. Stratton and \V. B. Alexander 
particularly. Among those who have given us valuable help or 
information (they have no responsibility for the use we have made of it) 



XV 



AUTHORS PREFACE 

are B. M. Arnold, R. Atkinson, J. Buxton, T. Cade, F. Darling, 
E. A. G. DufFey, A. Ferguson, Finnur GuSmundsson, H. G. Hasler, 
P. A. D. Hollom, J. S. Huxley, the late P. Jespersen, G. T. Kay, Miss 
J. Keighley, T. G. Lethbridge, H. F. Lewis, G.-F. Lundevall, S. 
Marchant, R. G. Murphy, E. M. Nicholson, R. S. Palmer, R. Perry, 
R. T. Peterson, L. E. Richdale, M. Romer, F. Salomonsen, H. N. 
Southern, D. Surrey-Dane, N. Tinbergen, L. Tuck, L. S. V. Venables, 
H. G. Vevers, K. Williamson and V. G. Wynne-Edwards. Mrs. E. 
Marshall patiently typed several drafts of most of this book. J. F. 
Trotter prepared the final copies of most of the maps. One of these is 
on a mapnet invented by the late Professor G. B. Fawcett and is used 
with his permission and that of the Royal Geographical Society (e.g. 
Fig. 24, p. 145). Another mapnet, devised by one of us (J.F.) is used 
for the first time in this book; it is based on the South Pole with the 
oceans in three petals, and is useful for showing the range of the many 
sea-birds that have a primarily southern distribution (e.g. Fig. 22, 
p. 136). J. Fisher's fellow New Naturalist editors have been encouraging; 
and Eric Hosking in particular has found us many unique photographs. 
R. Trevelyan, of Messrs. Gollins, has been most ingenious and helpful. 
The American Ornithologists' Union, who published our frontispiece 
first in the Auk, have very kindly allowed us the use of it; this fine 
painting by Roger Peterson of the interesting cahow, long thought to 
be extinct, embellished the paper by R. G. Murphy and L. S. Mowbray 
on their recent rediscovery of its breeding-grounds. 

Ornithologists' wives do many (if not most) of the chores that 
husbands normally do. We thank ours for more things than they 
probably remember. 

James Fisher 
r. m. logkley 



XVI 



CHAPTER I 

THE NORTH ATLANTIC OCEAN 
ITS STRUCTURE AND ITS SEA-BIRDS 



THE Atlantic Ocean is a big broad blind alley, kinked like a 
zig-zag, its jagged north end blocked with ice, its broader south 
butt cornered by the cold stormy narrow eastern entrance to the 
Pacific Ocean, and by the warm, windy and wide western gate to the 
Indian Ocean. It resembles two wedges, their apexes towards the 
North Pole, one of them truncated midway and at that point connected 
sideways to the base of the other. 

The birds inhabiting the more northerly of these wedges, the 
North Atlantic, are the birds of this book. Two of these birds have 
become extinct in historical times: the great auk was never seen alive 
after 4 June, 1844, and the last Labrador duck was shot in 1875, 
though some say one was shot in 1878. The number of living species 
that remain is about one hundred and eighteen, of which eighty-six 
have been seen on the western seaboard of Europe (which includes 
Iceland), and ninety-three on the eastern seaboard of the New World 
(including Greenland). 

However, for an understanding of the environment to which the 
North Atlantic birds are adapted, a description of the whole ocean is 
necessary, and to this we must proceed. 

The extremely simple fundamental shape of the Atlantic invites 
diagrammatic caricature (fig. i, p. 3). It is the second largest ocean in the 
world. It is, on an average, over two and a quarter miles deep, and 
in some places nearly six. It is, on an average, three thousand five 
hundred miles across (maximum about five thousand) ; and is nine 
thousand miles long. Its area has been estimated as thirty-three 
million square miles, and its volume as seventy-five million cubic 
miles. It is a vast place, with many miles of coast, upon which much 
of civilization depends: considering its size, it has few islands. In 



2 SEA-BIRDS 

comparison, the Indian Ocean is not quite as large (about twenty- 
eight million square miles) ; but the Pacific (about sixty-four million 
square miles) has nearly twice the area, and is ten thousand miles 
across its widest part. The Arctic Ocean (about five and a half million 
square miles) is small and nearly full of ice at all times of year; in 
spite of this it is at times very full of life. Finally, it is usual to describe 
the cold waters round the Antarctic Continent (itself the same size 
as the Arctic Ocean) as the Antarctic Ocean. 

South of the normal steamship route from Britain to New York 
the Atlantic is almost everywhere over two miles deep, and in large 
areas more than three. But down mid-ocean, following the tropical 
kink in the zig-zag, runs a very long submarine ridge, above which 
is less than two miles of sea; it is only broken by deeps for a short 
distance on the Equator, and it rises to the surface in places — in the 
northern hemisphere at the Azores and St. Paul Rocks, and in the 
south at the lonely isles of Ascension, Tristan da Cunha and Gough. 
Other oceanic Atlantic islands, such as Bermuda in the north, and 
South Trinidad and St. Helena in the south, rise abruptly from very 
deep parts of the ocean. A sketch-chart will be found on p. 30 
(Fig. 2c).^ 

It will be seen that there are prominent shallows along the east 
coast of southern South America, north of the mouths of the Amazon 
and along the Guianas, in parts of the Caribbean Sea and the 
Gulf of Mexico (there are also marked deeps in these tropical 
waters), off the New England States, Nova Scotia and (most particu- 
larly) Newfoundland, and round Britain, the Channel and the North 
Sea, and round Iceland. A submarine ridge, over which the sea is 
five hundred fathoms or less, cuts the North Atlantic entirely from the 
Norwegian Sea and the waters of the Polar Basin; Shetland, the 
Faeroes and Iceland lie on this ridge. Davis Strait is shallow, and 
the waters of Labrador and Hudson's Bay very shallow. Where the 
waters are less than a hundred fathoms deep, what they cover is 
usually described as the Continental shelf This has its own particular 
community of birds. 

For practical purposes, and because all charts and maps mark the 
Arctic Circle and the Tropics, we have classified the North Atlantic 
and its birds into arctic, temperate and tropical areas based simply 
on latitude. In our analysis of breeding-distribution, for instance 
(p. 22), we regard birds nesting north of the Arctic Circle as arctic, 
those nesting south of the Tropic of Cancer as tropical, and those 



NORTH 
AMERICA 




SOUTH 
PACIFIC 



INDIAN 
OCEAN- 



Fig. I 
Diagram of the Atlantic Ocean 



4 SEA-BIRDS 

nesting between as temperate. However, the temperature of neither air 
nor water arranges itself, in the Atlantic, according to latitude.* For 
instance, if we examine the July air isotherms over the world north 
of the Tropic of Cancer we see that that for 45° F. runs well south of the 
Arctic Circle in the areas Greenland-Baffin Island and Bering Strait, 
and well north of it off Scandinavia, avoiding Lapland altogether. 

If we examine a map of the world (showing particularly the 
lands between the Tropics), we see that the summer isotherm for 
80 °F. (July in the northern hemisphere, January in the southern) 
runs well north of the Tropic of Cancer in Mexico and the southern 
States, and in Africa and Asia, and south of the Tropic of Capricorn 
in Africa and Australia; yet large parts of the tropical Pacific and 
Atlantic Oceans never reach an average summer air temperature of 8o°F. 

In the North Atlantic there is not only relatively little direct 
correspondence between isotherms and latitude, but there is a 
good deal of difference in position between the same isotherms under 
the surface, on the water surface and in the air. 

The primary cause of the ocean currents, and of the prevailing 
winds which are associated with them, is the rotation of the earth. 
The plot of the Atlantic currents and Atlantic winds is almost, though 
not quite, coincident. To a very large extent the distribution of 
Atlantic water temperatures, and to a large extent that of air 
temperatures, is a consequence of these currents and prevailing winds. 
However, in parts of the Atlantic evaporation and the melting of 
ice produces temperature and salinity gradients which themselves 
produce consequent currents. Hence the web of sequence and con- 
sequence, of cause and effect, becomes complex. We must examine 
the great equatorial current first, for almost every one of the more 
important sea masses in the Atlantic owes its existence to it. It is 
quite justifiable to write in terms of sea masses, for, as we shall see, 
the Atlantic waters are by no means homogeneous and can be divided, 
sometimes with strikingly sharp boundaries, into volumes possessing 
very diverse properties. 

We need scarcely remind the reader that if he faces a globe, poised 
in the ordinary way with North at the top, and spins it as the earth 
naturally rotates, the points on its surface will travel, as they face him, 

*Maps of the northern part of the North Atlantic showing July surface-water 
isotherms, air-isotherms, vapour-pressure and relative humidity, and annual rainfall, 
are given by Fisher (1952, pp. 284-85); and a good map of August surface-water 
isotherms by Storer (1952, p. 186). 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 5 

from left to right. The points travelling with the greatest velocity will 
be those on the equator, and the two points represented by the Poles 
will travel with no velocity relative to the earth's axis. 

In general terms it is true that, as the earth rotates, its atmos- 
phere rotates with it. However, there is a certain effect due to inertia 
or drag; and this effect, obviously, is greatest at the equator, where 
the surface velocity is greatest. The efTect operates on all objects 
but can put only liquids and gases into a dynamic state. Upon 
these Corioli's force — the deflecting force of the earth's rotation — 
acts in a simple manner. It sets them in motion in a direction which, 
at the equator, is opposite that of the rotation of the earth. Thus if we 
examine a map of the prevailing winds and ocean currents of the 
world, we find pronounced positive east-to-west movements in all 
equatorial regions. The liquids and gases thus displaced circulate into 
the temperature regions and perform return movements in the higher 
latitudes where the Corioli's force is less. Consequently, in the northern 
hemisphere water and wind currents tend to turn right-handed, 
whereas in the southern hemisphere they turn left-handed. (Exceptions 
to this rule are mostly found in minor seas, where the impact of the 
currents upon coasts may cause contra-rotation.) The main clockwise 
movement of the northern hemisphere wind and currents is very 
obvious. (See the map on a back end-paper.) 

The Atlantic equatorial current can be traced from the African 
coast south of the equator westwards as far as the sea reaches. Approach- 
ing the coast of Brazil it attains a remarkable speed. It sets past the 
isolated oceanic island of Ascension so that even in calm weather it 
leaves a wake of turbulence which must make that island unusually 
visible from far off by its numerous bird inhabitants. 

Just north of the equator the lonely St. Paul rocks, which represent 
the pinnacles of a submerged, steep-sided mountain over thirteen 
thousand feet high, face the full strength of the great equatorial current, 
especially in August, when the associated south-east trades are blowing 
their hardest. During the cruise of the Challenger in i860 H. N. Moseley 
saw the great ocean current "rushing past the rocks like a mill race." 
A ship's boat was quite unable to pull against the stream. 

The equatorial current divides when it impinges on the corner 
of Brazil at Cape Sao Roque. The northern element — the Guiana 
coast current flows past the mouth of the Amazon with sufficient 
rapidity to displace the outgoing silt 100 miles or more in a northerly 
direction; and it continues steadily past the mouth of the Orinoco 



6 SEA-BIRDS 

and Trinidad to flow with scarce-abated force into the Caribbean, 
mainly through the channel between Trinidad and Grenada in the 
Windward Islands. 

Through the Caribbean the current flows from east to west, 
turning northerly and entering the Gulf of Mexico through the fairly 
narrow channel between Yucatan and Cuba. It is no doubt aided 
here by the climate, for this part of the world is very hot, and not 
excessively wet, and there is much evaporation of the waters of the 
Caribbean and the Gulf of Mexico, which has to be replaced. The 
current finally comes up against the coast of Louisiana and Texas 
and proceeds to mill right-handed, escaping finally through the narrow 
gap between Florida and Cuba, into the Bahama Seas. 

Here the Gulf Stream is formed, not only by the waters escaping 
from the Gulf of Mexico but by more northerly elements of the equa- 
torial current which impinge upon the outer shores of the West Indies 
and are deflected northwards. This north equatorial current flows 
across the ocean from the Cape Verde Islands and the joint product 
swings quickly east again, narrowing in width but probably gaining 
in velocity, to sweep past the tail of the Great Bank of Newfoundland 
and thence to carry on as what is now called the West Wind Drift 
(because of its associated air currents) . The most direct continuation 
of this drift flows northwards and eastwards past the west coast of 
Ireland (giving off* a branch towards Iceland), between Rockall and 
the Hebrides, through the channel between Shetland and Faeroe, 
north-eastward up the coast of Norway, whence elements strike east 
into the Barents Sea and north to reach Spitsbergen. It is because of 
this warm drift that, of all lands reaching latitude 80°, Spitsbergen 
has been the most accessible. If it was not for the Gulf Stream, many 
Oxford expeditions could never have explored there in the Long 
Vacation and got back in time for the Michaelmas Term. 

So far we have described the simplest and best-known currents 
of the North Atlantic. The fate of the waters in their return circulation 
is more complex. Much of the return circulation is below the surface, 
for cool water is denser than warm water. In the lower latitudes of 
the North Atlantic, between the westward-flowing north equatorial 
current, and the eastward-flowing Gulf Stream and drift, there is an 
area of clock-wise milling. The centre of this area is the part of least 
water-movement, and bears some resemblance to an oceanic desert. 
This is the Sargasso Sea, usually windless, too, with masses of the 
floating Sargasso weed, which has berry-like air vessels, and is used 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 7 

by sea-birds as a resting-platform ; but on the whole this stagnating 
area is as devoid of animal life as it is of movement. 

There is a corresponding and not dissimilar area in the South 
Atlantic, which also has calms. It has never been named, though 
it could well be called the Southern Sargasso. These Sargasso areas 
contain fewer plants and animals than any other part of the ocean. 
In both there is a rather fluctuating and not very well marked line or 
lines of convergence between the warm equatorial waters and the 
comparatively cool temperate waters. 

We must now return to the temperate waters, which, as we have 
seen, form a drift right across the Atlantic and into the Polar Basin. 
starting on the west below latitude 30 °N. and reaching latitude 70 °N, 
or more on the east side. The counter-movements and mills consequent 
on this great temperate drift are mostly in an anti-clockwise direction. 
Thus the waters of the North Sea tend to rotate anti-clockwise, running 
south down the British coast, east and north round the Heligoland 
Bight, and north-west from southern Norway. In the Norwegian 
Sea two major and several minor anti-clockwise mills can be detected, 
and the waters of the Barents Sea also tend to revolve anti-clockwise. 

But the greatest counter-movement in the North Atlantic is com- 
posed of the Greenland and Labrador currents, carr)dng cold, heavy 
water south past Labrador, past Newfoundland and far down the 
United States' eastern seaboard. This great counter current sets 
south along the east coast of Greenland down the Denmark Strait 
between Greenland and Iceland, round Cape Farewell, the southern 
tip of Greenland carrying with it many bergs tumbled from the sliding 
glaciers of the inhospitable east Greenland coast, runs north some 
hundreds of miles up the west coast of Greenland, then west and once 
more south, collecting the ice of Davis Strait and Baffin Island, and 
pursues its final course down the Labrador shore. As it turns the 
corner of Newfoundland and passes over the great shallow Banks, 
it deposits its last icebergs and suddenly impinges on the northern 
boundary of the Gulf Stream or W^est Wind Drift. Here a long, 
well-marked line of convergence extends for many hundreds of miles. 
The cold water sinks rapidly under the warm, and much turbulence is 
the result. Many organisms are brought to the surface. There is a 
steep temperature-gradient and frequent climatic upheavals, including 
fogs. It is largely because of the cold Labrador current that New 
York, though a full ten degrees farther south, enjoys a climate similar 
to that of London though with greater extremes of temperature. 



8 SEA-BIRDS 

The Atlantic thus is a mosaic, not a homogeneous area. Each 
patch in the mosaic is characterised by some pecuharity of climate. 
In practically all areas the water, the prime constituent, is in a state of 
continual movement. The fortunes and distribution of our sea-birds 
depend on this environment, so continually in turmoil. We must beat 
the bounds, then, of the North Atlantic and discover how our birds 
and their lives are interlocked with this climate and scenery. 

A suitable place from which to begin our tour of the North Atlantic 
is the St. Paul Rocks. Only three species of sea bird nest on them — 
the brown booby Sula leucogaster, and the noddy terns, Anoiis stolidus 
and A. minutus. The islands have been visited by many naturalists, 
including Charles Darwin, who spent some hours of the afternoon 
of 15 February 1832 obtaining bird specimens with his geological 
hammer! 

From here we move to the coast of South America between 
the Equator and the Caribbean: this is a mud-coast and not, as are 
many tropical coasts, a coral coast. Indeed, there is no sign of the 
coastal coral barrier-reef off Brazil until some distance south of the 
Equator. If we start at the Equator, on the islands in the mouth of 
the Amazon, we find a typical river bird-community. The water is 
fresh for some considerable distance outside into the ocean and the 
birds consist of skimmers {Rynchops nigra) and various river-loving 
terns such as the gull-billed tern Gelochelidon nilotica, the yellow- 
billed river-tern Sterna superciliaris, and the large-billed river-tern 
Phaetusa simplex. Off-shore the true sea-birds come in, and Murphy 
records species such as Leach's petrel, Wilson's petrel, the Tristan 
great shearwater, the great skua, boobies and tropic-birds. North of 
the Amazon mouth the Brazilian Guiana coast is forested down to 
the muddy shore. Many small rivers, often choked with the debris of 
tropical forests, flow into it. 

In French Guiana, however, rocky promontories and islets appear, 
and they are inhabited by some sea-birds; regrettably little is known 
about the species involved, but they probably include boobies and 
tropic-birds. Along the coast of Dutch and British Guiana we are once 
more in a muddy coast with no headlands or islands. North-west 
of the mouth of British Guiana's main river, the Essiquibo, there are 
some shell-beaches, but most of the coast is of mangrove-swamp 
jungle, in which the only animal resembling a sea-bird is the Mexican 
or bigua cormorant Phalacrocorax olivaceus. Over the Venezuelan 
border we are at once in the delta of the great river Orinoco. It is a 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC g 

land of dense mangrove forest and a very large number of low wooded 
islands. Off-shore the immense tonnage of mud and silt is seized 
by the equatorial current and driven northwards towards Trinidad, 
which it thus provides with a very wide continental shelf. As Murphy 
(1936, p. 127) writes, "The delta of the Orinoco is not the home of 
birds that can be called marine. . . . Only our adaptable old friend the 
Bigua cormorant seems ... at home." 

Generally speaking, from the mouth of the Amazon to the mouth 
of the Orinoco the coast scarcely harbours a breeding sea-bird. 
However, the British islands of Trinidad and Tobago, off the north- 
east corner of Venezuela are provided with rocky promontories and 
many islets on which sea-birds nest. The brown pelican Pelecanus 
occidentalism the red-footed booby Sula sula, the man-o'-war or frigate- 
bird Fregata magnijicens ^ nest on low trees or on mangroves. On the 
bare Soldado rock the sooty tern Sterna fuscata^ and the two species 
of noddy, nest. One tubenose, Audubon's shearwater Puffinus 
rherminieriy nests on Tobago, which is its southernmost breeding place 
on this coast. The gull-billed tern nests in fresh water marshes. 

West of Trinidad we are in the Caribbean Sea and following the 
coast, which for 250 miles more has a wide continental shelf, with 
small islands dotted in it. Opposite the western part of Venezuela, 
however, the water is much deeper close in-shore, and the off-coast 
islands of Curasao and other Dutch possessions rise from a deep sea. 
Both the islands of the shallow shelf, such as Los Hermanos and the 
Testigos, and these Dutch islands, have many sea-birds, including three 
kinds of boobies, man-o'-war birds, tropic-birds, noddies and sooty 
terns. At least eight species of terns are found at Aruba, the western- 
most of the Dutch islands. But there are few species which can be 
described as oceanic, though the boobies are marine; many of the 
sea-birds probably nest on the islands rather than on the mainland 
because of the additional safety and the existence of outcrops of rock 
such as are not found along the interminable mangrove coast. 

Of all coasts that we have so far considered, those of northern 
Venezuela are the driest, and the Caribbean is the hottest part of the 
North Atlantic region. The western Caribbean, however, has intense 
summer rain; in spite of this, evaporation is great and the equatorial 
current is boosted along, flowing into the Gulf of Mexico with some 
rapidity. 

In the Antilles, which form the eastern and northern boundaries 
of the Caribbean Sea, we find islands clad still in fairly thick jungle 



10 SEA-BIRDS 

vegetation, with coastal mangroves, but also many sandy islets and 
bars and real coral reefs. Though the Guiana coast was too muddy 
to support coral reefs, these are found fringing the islands north of 
Venezuela, such as Curasao. There are also many reefs along the 
western shore of the Caribbean, particularly at the corner of Nicaragua 
and Honduras, at the end of the shallow Mosquito Bank. Throughout 
the West Indies the distribution of sea-birds is linked primarily with 
available food, but that of the breeding adults probably also with 
available nesting-sites. Islets where there are exposures of rock or 
sand are much favoured, but some species as we have seen, including 
the red-footed booby, the brown pelican, the bigua cormorant, the 
darter Anhinga anhinga, and some terns, nest in trees. One very rare 
petrel Pterodroma hasitata (p. 76) nests above the tree-line on some of 
the West Indian islands, among the rocks of steep mountains. 

A typical sea-bird islet in the West Indies is Desecheo, described 
by Alexander Wetmore. This lies in the hot dry zone west of Porto 
Rico. It is a rocky islet with cliffs and a gravel beach, and a thin 
top-soil covered with a dense thicket of cacti and the curious West 
Indian birch. Here brown boobies nested on the ground among the 
thickets and floundered through the prickly pear and cactus. Sooty 
terns nested on ledges, on shelves on the limestone cliffs, and B. S. 
Bowdish found a few bridled terns Sterna anaetheta, nesting on flat 
ledges. This species also breeds on the little islets or cays of the Barrier 
Reef south of Jamaica, among the broken coral rock and the man- 
groves. 

North of the Antilles the low-lying British islands of the Bahamas 
occupy a large area of the west Atlantic. The blue Atlantic beats 
directly against steep east-facing limestone cliffs, while to the west 
there are shelving beaches. Many of these islands are covered with 
cacti, and the sea-grape Coccolobis, which forms low, thick vegetation 
in which brown boobies nest, scraping slight hollows in the ground 
and lining them with grass. In some Bahamas the man-o'-war bird 
builds its nest quite on top of the prickly pears, though more normally 
on the mangroves in the swamps, together with brown pelicans and 
the double-crested cormorant of Florida Phalacrocorax auritus floridanus. 
Upon the more exposed sandspits in the Bahamas several kinds of 
tern breed, including the gull-billed tern, the little tern Sterna 
albifrons, the roseate tern S. dougallii, Cabot's tern Thalasseus 
sandvicensis , and the sooty tern. 

The coast of the Gulf of Mexico is low-lying, with coral reefs 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC II 

and an extensive continental shelf, especially off Yucatan. Breeding 
sea-birds are scarce, except terns and the ubiquitous bigua cormorant, 
which is as much a fresh-water as a salt-water bird. The Sandwich 
tern, which is known as Cabot's tern in North America, breeds in 
several parts of the Gulf coast of Mexico, which is more suited for 
terns than for any other sea-birds. On the grassy islands among the 
lagoons and marshes of the Texas coast, the gull-billed tern and 
Forster's tern Sterna forsteri, are found. The beautiful Caspian tern 
Hydroprogne caspia, also nests in a few places on sandy islands, and 
there is an interesting outpost breeding-station of the white pelican 
Pelecanus erythrorkynchos, on the Laguna de la Madre, south of Corpus 
Christi, near the Border. The rest of the population of this fine bird 
is found in western North America. 

Along the Louisiana coast, where there are many protected reserva- 
tions, there are very big colonies of the laughing gull Larus atricilla, 
especially in the marshy islands of the Mississippi delta, which are 
overgrown with grass and low mangroves. One of the reservations 
is in the Breton Islands, 114 miles off the main Louisiana coast. 
Here are great colonies of terns on low flat sandy spits, including 
Caspian, Cabot's and royal Thalasseus maximus (Bent 192 1). Forster's 
and common terns Sterna hirundo, also nest in the Breton Islands" as 
do numbers of the extraordinary black skimmer, an aberrant tern 
whose lower mandible is prolonged and with which it scoops food 
from the surface of the sea. The peninsula of Florida has to its west an 
immense continental shelf, along the lower end of which is a famous 
chain of Keys. Beyond Key West, at the terminus of the Key railway, 
many miles to sea, lie the dry Tortugas, flat islands of coral, their 
surface, largely of coral sand, clothed in parts with dense cactus as 
well as with bay cedar, with many bare and grassy spaces between. 
On the cedars and the cactus immense numbers of noddy terns nest: 
often over the nests of the sooty terns on the ground below. 

The Florida coast has one of the best stations in the U.S.A. for the 
roseate tern. The darter, which most North Americans allude to as 
the water-turkey (it is a fresh water lover), and the double-crested 
cormorant of Florida, commonly nest in trees in many swampy places 
along the coast. Brown pelicans nest by lagoons and in mangrove- 
keys on both sides of the peninsula. 

Naturalists accustomed to British coast conditions can have little 
notion of the interminability of the low-lying eastern coast of North 
America. Indeed, on the entire stretch of mainland coast from Southern 



12 SEA-BIRDS 

Mexico to Maine, about four thousand miles, there is not a single cliff, 
nor indeed a mountain coming down to the sea. All through Florida, 
Georgia, the Carolinas, Virginia and Maryland to the New England 
States, runs a complex of lowland and shallow shores, broken in places 
by inlets such as those of Chesapeake and Delaware Bays and Long 
Island Sound. This is a tern coast. In the northern parts the effect 
of the Labrador current is felt and there is a fairly steep decline in 
temperature, which is why such tropical forms as the brown pelican 
and Florida double-crested cormorant drop out of the community 
in South Carolina. One tropical species which is distributed all along 
this coast, however, is the laughing gull ; and the gull-billed tern reaches 
north to Virginia. Rather oddly, two terns, the common tern and 
Forster's tern, appear to avoid the mainland coast from Florida to 
South Carolina, though they breed to the west and north of it. 

The distribution of tern populations on this Atlantic coast has had 
a chequered history, and is dealt with in some detail in the chapter 
on Sea-Bird Populations (Chapter 3, p. 85). 

In the New England States and Maine we encounter the first 
truly northern elements in the Atlantic sea-bird fauna, and a com- 
munity of sea-birds which is intensively watched and studied, as is 
the very similar community on the eastern side of the Atlantic, ten 
degrees farther north. We now meet not only some of the terns but 
some of the gulls that breed in the British Isles. In Maine and New 
Brunswick, where little cliffs begin and the wooded coast closely 
resembles the skerry-guard of Stockholm, and other parts of the 
Baltic archipelago, we find the southernmost auks — black guillemots 
Cepphus grylle, puffins Fratercula arctica, and perhaps still a pair or two 
of razorbills Alca torda. We even find tubenoses breeding in Maine, 
birds which we had last encountered in the Caribbean Antilles. 
(Apart from Audubon's shearwater and the rare diablotin (p. 76), 
which nest in various of the Antilles, no breeding petrel is found in the 
western North Atlantic south of Maine, save on Bermuda.) 

The rocks and coral reefs of Bermuda, which is 580 miles from 
Cape Hatteras, the nearest point on the United States mainland, 
support an interesting little community of sea-birds, which consists of 
the northernmost outposts of the breeding population of an otherwise 
completely tropical species, the white-tailed tropic bird Phaethon 
lepturuSi besides the common tern, the roseate tern, possibly the Manx 
shearwater Puffinus puffinus, Audubon's shearwater, and the cahow 
Pterodroma cahow ^ thought to be extinct for many years. 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC I3 

It is in the Bay of Fundy, then, on the borders of the U.S. and 
Canada (Maine and New Brunswick) that the northern birds really 
begin. Here in burrows in the island rocks nest the southern elements 
of the rather small Atlantic population of Leach's petrel Oceanodroma 
leucorhoa. Here, too, are the representatives of the northern race of 
double-crested cormorant, which are separated by a gap of some hun- 
dreds of miles from the geographical race of the same species belonging 
to Florida and the Carolinas. 

Other birds which come on the scene between Cape Cod and the 
Bay of Fundy are the great black-backed and herring-gulls. Lams 
marinus and L. argentatus^ which are now quickly spreading south down 
the coast, and the arctic tern Sterna paradisaea, which still nests as far 
south as Cape Cod. If we move north to the Gulf of St. Lawrence, 
we can also bring in an outpost population of the European cormorant 
Phalacrocorax carbo, the ring-billed gull Larus delawarensis, which is 
very closely related to our common gull, the common guillemot 
Uria aalge, and, rather surprisingly, an arctic species, Briinnich's 
guillemot Uria lomvia, whose breeding distribution extends from the 
Magdalen Islands via Newfoundland and Labrador to the High Arctic 
There is a curious relict population of the Caspian tern also here. 
In many ways the Gulf of St. Lawrence has arctic properties and 
there is, as we have seen, a very steep gradient in water temperature 
at its mouth, at the convergence of the west wind drift and the Labrador 
current. Here we find the southern outposts of the largest temperate 
North Atlantic sea-bird, the gannet Sula bassana — though the majority 
of its breeding-population is found on the other side of the ocean; 
and we meet our first kitti wakes Rissa tridactyla. 

In structure the coasts of the Atlantic right round from Maine via 
Nova Scotia, the Gulf of St. Lawrence, Newfoundland, Labrador, 
Greenland and Iceland to Britain, have a good deal of similarity. 
They have a fairly even supply of estuaries, inlets, beaches, sands, 
cliffs, skerries, stacks and islands, and it is probable that the distribu- 
tion of no sea-bird is seriously limited by lack of suitable nesting sites. 

There are two inland species of North American dark-headed gull, 
Franklin's gull Larus pipixcan, and Bonaparte's gull L. Philadelphia, 
neither of which breeds near the coast. 

From the Gulf of St. Lawrence, via Newfoundland, Labrador, 
Greenland and the Canadian Arctic Archipelago, we find a gradual 
disappearance of the temperate, sub-arctic and some low arctic species 
as we progress towards the shores where the sea is still near-freezing 



I^ SEA-BIRDS 

in July — the true High Arctic. In Newfoundland we reach the limit 
for breeding gannets, ring-billed gulls and common terns, and perhaps 
also Caspian terns. The Leach's petrels breed as far as Newfoundland 
Labrador, but no farther, and it is doubtful whether the double- 
crested cormorant now breeds as far. South-west Greenland is less 
'arctic' than opposite parts of the Canadian Arctic Archipelago at the 
same latitude; and it is not surprising that some species extend beyond 
Labrador to West Greenland, though not to Baffin Island and the 
other Canadian islands. Such species are the razorbill and common 
guillemot, the latter having only one small colony in West Greenland. 
The European cormorant extends to West Greenland and previously 
had a small outpost in Baffin Island, from which it has now disappeared, 
and it is also extinct in Newfoundland Labrador, after much human 
persecution. The puffin does not breed in the Canadian Arctic but 
goes far north in Greenland where it is of a distinctive, large arctic race. 

Species which extend in breeding-range all the way from Newfound- 
land to Arctic Greenland and Canada are the herring-gull, great black- 
back, kittiwake, arctic tern and black guillemot. All these except 
the blackback reach the High Arctic, if we regard the Iceland gull 
Lams argentatus glaucoides, as a herring- gull, as we think we should. 

The glaucous gull Larus hyperboreus, does not now breed in New- 
foundland, but nests commonly from Newfoundland Labrador all 
the way to the High Arctic, as does the arctic skua Stercorarius para- 
siticus; two other skuas, the pomarine S. pomarinus, and the long- 
tailed skua S. longicaudus, do not breed in Labrador, but farther north 
in both Canadian and Greenland Arctic. On the west side of the 
Atlantic-Arctic the fulmar Fulmarus glacialis, breeds no farther south 
than Greenland and Baffin Island, although it nests south to about 
latitude 50° north on the east side of the Atlantic. 

This leaves the three High Arctic sea-birds of the West Atlantic 
for consideration — the little auk Plautus alle^ Sabine's gull Xema sabini, 
and the ivory-gull Pagophila eburnea. All three breed in the more 
northerly parts of the Canadian Arctic Archipelago and Greenland, 
though the first may not have more than one colony west of Baffin's 
Bay. Sabine's gull is a rare bird that often nests in arctic tern colonies. 
The ivory-gull is the most northerly bird in the world in the sense 
that it breeds nowhere south of the Arctic Circle, but as far north as 
the land goes. The extraordinary, rare, Ross's or rosy gull Rhodostethia 
rosea, which normally nests in the aldergroves of some north-flowing 
rivers of eastern Siberia, has once bred in Greenland. 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 



15 



Canad- 
ian 
Arctic 



Green-, Jan 

LAND MaYEN 



Bear 
Island 



Spits- Franz t^- 

t [jnovaya 

ber- Josef U 

% Zemlya 

gen Land 



Arctic 
Euro- 
pean 
Russia 



Arctic 
Nor- 
way 



Fulmar -r-r4- + + + -r — — 

Shag ..__ — — — — — 4. ^ 

Cormorant extinct + — — — — — + + 

Pomarine 

skua . . + + — — — casual + casual — 

Arctic skua + + + + + + + + + 

Long-tailed 

skua + + once — casual — + + + 

Ivory-gull + + — — + + — — — 

Common 

gull ..— + — ? ___ + 4- 

Herring-guU 

(inch "Ice- + + ? casual — — — + + 

land" gull) 
Lesser 

blackback — — — — — — 4- + + 

Great 

blackback + + — recent recent — — -f 4- 

Glaucous 

gull ..+ + + + + + + + — 

Ross's gull — once — — — — — — — 

Kittiwake + + + + - + + + + 

Sabine's 

gull . . + + — — + — — once — 

Common 

tern . . — — — — — — — casual casual 

Arctic tern + + recent + + + + + + 

Little auk ? 4- + + + + + — — 

Razorbill — + — ? ___ + + 

Briinnich's 

guillemot +4- + 4- + + + + _ 

Common 

guillemot — 4- — 4- — — 4-4- 4- 

Black 

guillemot 4-4-4-4-4-4-4-4-4- 
Puffin ..— 4-4-4-4- — 4-4- + 



The breeding sea-birds of the lands and islands north of the Arctic 
Circle belonging to the Atlantic or the Atlantic section of the Arctic Ocean, 



l6 SEA-BIRDS 

With the exception of a few gulls, sea-birds entirely desert the 
arctic regions bordering Baffin's Bay and Davis Strait in October and 
do not return until April. From no other part of the northern hemi- 
sphere is there so great a withdrawal of sea-birds to avoid a period of 
inhospitable climate. 

The eastern arctic islands — Jan Mayen, Bear Island and Spits- 
bergen, Franz Josef Land and Novaya Zemlya, which lie across the 
Polar Basin where it abuts on the North Atlantic, have a very similar 
breeding sea-bird community to that of Greenland, though none has 
so many members. We can best make this comparison in the form of 
a table, adding columns for the Canadian Arctic, Arctic Russia-in- 
Europe and Arctic Norway. (Page 15.) 

We now come to the seabird community of Iceland, Faeroe, the 
British Isles, Scandinavia, the Baltic, and the North Sea and English 
Channel. This community is very homogeneous, considering the range 
of latitude over which it is spread, though there are some members 
which do not reach the south end of this range and a few which do 
not reach the north. Among the species which are found over almost 
the entire twenty degrees of latitude are the Manx shearwater, the 
storm-petrel Hydrobates pelagicus, the gannet, the shag Phalacrocorax 
aristotelis, the cormorant, the herring-gull, the lesser blackback 
Larus fuscus, the great blackback, the black-headed gull L. ridibundus, 
the kittiwake, the common and arctic terns, the razorbill, the guillemot, 
and the puffin. Species which occupy the more northerly parts of 
this temperate European stretch incUide the great skua Catharacta 
skua, and Leach's petrel (Iceland, the Faeroes and Britain only), the 
fulmar, the arctic skua, and the black guillemot. The glaucous gull, 
little auk and Briinnich's guillemot breed (in this part of the Atlantic) 
only in Iceland. 

There is a central group of sea-birds which breeds neither as far 
north as Iceland nor as far south as Atlantic France; this is headed 
by the common gull Larus canus, and includes also the little gull L. 
minutus; its other members are terns, the whiskered tern Chlidonias 
hybrida (only casual, in Holland), the black tern C. nigra, the white- 
winged black tern C leucoptera (casual only), the gull-billed tern and 
the Caspian tern. The populations of all these terns are low, and only 
two of them (black and gull-billed) have recently bred in Britain, 
and that casually; their headquarters lie between Holland and the 
South Baltic. The Baltic Sea, though it has as many breeding terns 
and gulls as any other part of this stretch of the east Atlantic, lacks 

Plate 2. Storm petrel incubating in a rock-crevice on Skokholm, Pembrokeshire 






Plate 2. 



Robert Atkinson 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC I7 

tubenoses and has no gannets, shags, kittiwakes or puffins. The 
long-tailed skua has a somewhat specialised breeding distribution in 
Lapland, mostly inland. The remaining birds of this temperate 
stretch of the east Atlantic breed from Britain, the North Sea or the 
Baltic south beyond its limits; they are the roseate, little and Sand- 
wich terns. Britain is the European headquarters of the roseate tern. 

About half the members of this east and north Atlantic temperate 
sea-bird community are truly oceanic; that is, they may be found in 
mid-ocean, up to the greatest possible distance from land, wherever 
there are suitable feeding waters. Storm-petrels, Leach's petrels and 
fulmars are the oceanic tubenoses of this community, and we now 
find that the Manx shearwater also has a right to be considered 
oceanic. Among the auks the dovekie and Briinnich's guillemot from 
the north join the puffins, razorbills and guillemots in ocean wander- 
ings. Here, too, are found all the four skuas of the northern hemisphere 
and one, but only one, gull — the highly specialised kittiwake. In the 
waters a hundred fathoms deep or less, that is, on the so-called conti- 
nental shelf, we find all the birds previously mentioned, together with 
the gannet, the black guillemot, and gulls of the genus Larus — the 
great blackback, the lesser blackback and the herring-gull. Once we 
are within sight of shore quite a number of species are added to our 
list, and the tubenoses, except for the Manx shearwater and fulmar, 
drop out. Here are the terns, the black-headed and common gulls, 
and also the cormorant and shag, the one haunting mostly seas in 
sight of sandy shores, and other seas in sight of rocks. 

By far the most impressive of the sea-bird haunts are the breeding 
cliffs, where the different species are zoned vertically as well as hori- 
zontally. Whether the rocks be volcanic or intrusive or extrusive or 
sedimentary, we are sure to find Larus gulls breeding on the more 
level ground a little way back from the tops of the cliffs — fulmars on 
the steeply sloping turf and among the broken rocks at the cliff edge, 
puffins with their burrows honeycombing the soil wherever this is 
exposed at the edge of a cliff or a cliff buttress, Manx shearwaters or 
Leach's petrels in long burrows, storm-petrels in short burrows and 
rock-crevices, razorbills in cracks and crannies and on sheltered 
ledges, guillemots on the more open ledges where they can stand; 
perhaps gannets on broad flat ledges or on the flattish tops of inacces- 
sible stacks, cormorants with their nests in orderly rows along broad 
continuous ledges, shags in shadowy pockets and small caves and 
hollowed-out ledges dotted about the cliff, kittiwakes on tiny steps 



l8 SEA-BIRDS 

or finger-holds improved and enlarged by the mud-construction of 
their nests, tysties or black guillemots in talus and boulders at the foot 
of the cliff. These wild, steep frontiers between sea and land are exciting 
and beautiful. They probably house larger numbers of vertebrate 
animals, apart from fish, in a small space, than any other comparable 
part of the temperate world. 

Not many sea-birds of the east Atlantic do not breed on clifis; 
but the skuas nest on moors, and the terns and black-headed gulls 
nest on sand and shingle. Many of the Larus gulls, and recently the 
fulmar, are catholic in their taste in nesting sites, and may be found 
on moors and even sand dunes. Quite a large number of sea-birds can 
be inland nesters, even including tubenoses. Fulmars now nest up 
to six miles inland in Britain, and many of the Larus gulls at much 
greater distances. The black-headed gull, in particular, is often a 
completely inland species, since some individuals nest in England as 
far as they can from the sea, e.g. in Northamptonshire, and may never 
visit it except in casual search for food. 

As we go south along the Atlantic seaboard of the Old World 
we leave behind in the Channel Islands and Brittany the last elements 
of certain temperate cliff-breeding sea-bird species — the gannet, 
lesser blackback, great blackback, arctic tern (only a casual breeder 
so far south), razorbill and puffin. South of the Bay of Biscay we en- 
counter a large sub-tropical and tropical community of about forty 
species (a few of which belong to sea-bird families but which have 
become river-birds or inland birds), which is distributed in four main 
geographical regions — the Lusitanian coast (the Atlantic coast of 
Spain and Portugal), the Mediterranean, the Atlantic coast of Africa 
north of the equator, and the Atlantic Islands. These last comprise 
the Azores, Madeira (to which pertain the Desertas and Salvages), 
the Canaries and — near the equator — the Cape Verde Islands. Many 
species breed, of course, in more than one of these regions, though 
only the herring-gull (rather doubtfully the little tern and cormorant) 
breeds in them all. 

Of the species in the table, the crested pelican Pelecanus roseus, the 
pigmy cormorant Halietor pygmeus, the Mediterranean black-headed 
gull Larus melanocephalus, and the lesser crested tern Thalasseus bengalensis 
breed on no North Atlantic shore, and the rare slender-billed and 
Audouin's gulls, Larus genei and L. audouinii, are primarily Mediterranean 
species. It will be noted that three tubenoses have established them- 
selves in the Mediterranean, but that no less than eight species breed 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 



19 



in the Atlantic Islands, which have a greater variety of species of this 
order than any other part of the North Atlantic. 

The distribution of breeding sea-birds on these coasts is best 
illustrated in tabular form : 





Atlantic 
Spain 

AND 


Medit- 


L 


^lTLANTIC 


Islands 










Madeira 




Cape 


North 




ERRAN- 


\7ORFS 


Desertas 


Canar- 


Verde 


Atlantic 




Portugal 


EAN 


^ \.£j\J P^I—itJ 


& Sal- 


ies 


Islands 


Africa 












vages 








North Atlantic 
















shearwater . . 


+ 


4- 


+ 


+ 


4- 


+ 


— 


Manx shearwater 


— 


-t- 


+ 


+ 


• — 


— 


— 


Little shearwater 


— 


— 


+ 


-r- 


-t 


+ 


— 


Soft-plumaged 
















petrel 


— 


— 





+ 


— 


+ 


— 


Bulwer's petrel 


— 


— 


-r 


+ 


+ 


+ 


— 


Frigate-petrel 


— 


— 


? 


-h 


+ 


-r 


— 


Storm-petrel . . 


p 


^ 


— 


p 


-f 


— 


— 


Madeiran fork- 
















tailed petrel 


— 


— 


+ 


+ 


— 


-f- 


— 


Red-billed 












• 




tropic-bird . . 


— 


— 


— 





— 


4- 


— 


White-tailed 
















tropic-bird . . 


— 


— 


— 





— 


— 


-V 


Crested pelican* 


— 


p 


— 





— 





— 


White pelican* 


— 


? 


— 





— 





+ 


Pink-backed pelican ' 


< 


— 


— 





— 





-f- 


Brown booby . . 


— 


— 


— 





— 


+ 


+ 


Shag . . 


+ 


^ 


— 





— 





1 ** 


Cormorant 


p 


-r 


— 





— 


-f 


-f 


Reed-cormorant * 


— 


— 


— 





— 





-+- 


Pigmy cormorant* 


— 


? 


— 





— 





— 


African darter 


— 


— 


— 





— 





-^- 


Man-o'-war-bird 


— 


— 


— ■ 





— 


+ 


p 


Herring-gull . . 


+ 


T 


+ 


-f 


+ 





1 ** 


Black-headed gull 


— 


-T 


— 





— 








Mediterranean 
















black-headed gull 


— 


+ 


— 





— 








Slender-billed gull 


+ 


+ 


— 





• — 





'3* * 


Audouin's gull 


■? 


+ 


— 





- — 








Grey-headed gull* 


— 





— 





— 





+ 


Whiskered tern 


-V 


+ 


— 





— 





1 "K ^ 


Black tern 




+ 


— 





— 





— 


White-winged 
















black tern . . 


casual 


casual 


— 





— 





— 


Gull-billed ter 


n 


4- 


--t- 


— 





— 


— 


?** 



20 






SEA-BIRDS 










Atlantic 


Medit- 


Atlantic Islands 






Madeira 




Cape 


North 




Spain 


erran- 


Desert AS 


Canar- 


Verde 


Atlantic 




AND 


ean 


Azores ■ & Sal- 


ies 


Islands 


Africa 




Portugal 




1 VAGES 








Caspian tern . . — 


+ 


_ 


, 





? 


Common tern + 


+ 


+ + 


? extinct 


— 


— 


Roseate tern . . — 


+ 


extinct extinct 


— 


— 


— 


Bridled tern . . — 


— 


— — 


— 


— 


? 


Sooty tern . . — 


— 


— — 


— 


— 


? 


Little tern . . + 


+ 


? 


? 


— 


+ 


Royal tern . . — 


— 


— — 


— 


— 


? 


Lesser crested tern — 


+ 


— — 


— 


— 


— 


Sandwich tern ? 


+ 


— — 


— 


— 


— 


Noddy . . — 


— 


— — 


— 


— 


+ 


African skimmer * — 


— 


— — 


— 


— 


+ 


Guillemot . . + 




— — 


— 


— 


— 



The Sea-birds breeding in the Eastern North Atlantic south of the 
Bay of Biscay and in the Mediterranean. 

* mainly fresh water and estuarine. ** Morocco only. 

Of the four main groups of these Atlantic islands, Madeira and 
the Cape Verdes have probably the largest sea-bird communities, 
with ten or a dozen species each. One tubenose, the North Atlantic 
great shearwater, Puffinus diomedea, nests on all of them as well as on the 
Berlengas of Portugal. Bulwer's petrel, Bulweria bulwerii, and the little 
dusky shearwater, Puffinus assimilis, also nest on all four island groups. 
The Madeiran fork-tailed petrel, Oceanodroma castro, nests on all but 
the Canaries. The Manx shearwater nests on the Azores and Madeira, 
but not yet farther south. The little storm-petrel reaches south to 
the Canaries (although in small numbers and probably to these Atlantic 
islands only). The rather rare soft-plumaged petrel, Pterodroma mollis, 
is believed to nest on Madeira; it does so on the Cape Verdes. The 
beautiful frigate-petrel, Pelagodroma marina, breeds on the Salvages 
(which belong to Madeira but are nearer the Canaries), the Canaries 
and the Cape Verdes. 

The red-billed tropic-bird, Phaethon aethereus, the brown booby 
and the frigate-bird (man-o'-war bird) do not appear farther north 
than the Cape Verdes. Here the cormorant, which had dropped out 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 21 

in Morocco, reappears as a new race, primarily South African. The 
bird communities of these islands are only moderately well-known. 
Most of the sea-birds nest on rocks whose comparative inaccessibility 
has been both a temptation and a deterrent to the visiting ornithologist. 
As for the coast of West Africa and the islands lying close to it, no 
organised investigation of the sea-bird communities of this difficult 
region has yet been made. We know that one group of species breeds 
on the Atlantic African coast to Morocco, but no farther south — 
the shag, herring-gull, the whiskered tern, probably the gull-billed 
tern, possibly the slender-billed gull. Farther south both white and pink- 
backed pelicans, Pelecanus onocrotalus and P. rufescens, and the grey-headed 
gull. Lams cirrhocephalus, reach the tropical sea-coast in some places, 
and the brown booby nests on at least one island off the coast of 
French Guinea. The Caspian tern, whose world distribution is, to 
say the least, peculiar, may have breeding stations on this coast, and 
the little tern, which we had left behind in Morocco, reappears as a 
separate race on the coast and rivers of the Gulf of Guinea. 

The African darter, Anhinga rufa, reed-cormorant, Halietor africanus, 
and the African skimmer, Rynchops flavirostris, haunt the rivers and in 
places reach the coast; but they are not sea-birds: and on islands in the 
Gulf of Guinea the noddy and the white-tailed tropic-bird, Phaethon 
Upturns, breed. It is suspected that the frigate-bird may nest on this 
coast, but its breeding-place has not been found. Neither has that 
of the bridled tern. Sterna anaetheta, or the sooty tern, S. fuscata, although 
both species are seen in considerable numbers. There is at least one 
other riddle: a population of the royal tern, Thalasseus maximus, 
haunts almost the whole coast of West Africa from Morocco to some 
hundreds of miles south of the Equator. Systematists have separated 
it from the West Atlantic population as a subspecies {albidorsalis) , on 
valid differences, and it does not appear to leave this coast, yet no 
ornithologist has yet seen its nest or even its eggs. 

Only in the tropical parts of the Atlantic are there still these distribu- 
tional queries. In the temperate and arctic zones the breeding places 
of the birds are well-known and described. And with this little mystery 
we conclude our tour of the Atlantic, for we are back on the equator 
and can strike west to the St. Paul Rocks, where we began. 

The sea-birds of the North Atlantic can be listed in the form of a 
table (Appendix, p. 292), and plotted according to which parts 
of the ocean they breed in, in the form of a diagram (Fig. 2) . For 
the purpose of completeness, the secondary sea-birds have been 



22 



SEA-BIRDS 




Fig. Q.a 
The breeding sea-birds of the North Atlantic, arranged by five 
geographical regions. No species breeds in more than four. Number 
of species; see opposite page for actual species 



included, those belonging to families whose fundamental evolution 
has ])robably been non-marine (like anatids and waders) or which are 
only sea-birds in winter (divers and grebes). Only the more important 
of these are on the diagram, and they are not otherwise treated in this 
book. It is interesting that more than half of them are northern ducks 
which winter at sea, though usually within sight of shore. 

It must also be pointed out that several species belonging to the 
families of primary sea-birds have secondarily taken to life inland, 
on rivers, or on estuaries, and may reach the sea only incidentally 
or not at all. Certain West African species, in particular, are river- 
birds (the pelicans Pelecanus onocrotalus and P. rufescens, the reed- 
cormorant Halietor africanus^ the darter Anhinga rufa, the skimmer 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 

^V^' h-ory-guti . .JN 

/ ; in . ti cifeUers eider 
'^little auk tfpsss gu/J ^^Smev 

'ing - eider ^„^--''^^~'~---.,^9 <; er hlackback 

Fomarine skua ,.-<f , ,, , t ,. ^\^ ^ ^/.^/„^ 
, , , Z^ Red- threaded diver ^-^-^—ocoter 

Iceland X Black-throaied diver \. Men' 
'ooded i'"" y/ Great northern diver \^^uU 

^ I oahines /Slavonian grebe Rednecked grebe \ 

S"ii /Fulmar long - tailed dm-k Eider \^'^ 

Velvet-scoter Goosander Red- breasted meryt 
flM / Grey phaloTope Red-necked phalarope 

Arctic skuxt Long -tailed skua Great black-bark 
Glaucous gull Kitiiwake Arctic tern 

Razorbill BriianicKs guillemot Guillemot 



'^3 



** / scoter 
Ring-billed 



Forster's 
tern 



American 

white 

pelican 



leacti 
petreb 
Black^ 

tern 
Gannei. 



Storm- 
petrel 



Little gull 



Black guillemot 



Common 
tern 



Puffin 



Herring-gull 
J?ormorani 



Vj 



Gull-billed tern 
Roseate tern 
Sandwich 
tern 



laugh 
/gull 

Cahow /Pied-bille> 
I grebe — 
iBrown pelican-^ 
I Douhle-crestedy^ 
I cormorant ^ 
iMexican. cormorant 

duhods s kearwat^!]\ 
American ^ Noddy 
^ dartei^^ ' -^ 
^^lack 

"^skimmerX 
"-^..^ 

Blue faced booby 

.Red-footed booby 

*P \ 
'^i^\Large -billed tern 



Little tern 



Royal tern 



iaiUd J 
c birg^ 



jvptc^ 



Black- necked 

grebe iDaS 
-, . chick 

5 Jbreat 

tern /crestedgrci 

y'orfhAt/antic 
shearwater 
, 'Bulwer's petrel 
Frigate petrel 
-*—LiUle shearwaler, 
Madeiran 

storm-petrel 
Scft-plumage^ 
- .peivelf£^^_ 

cormorant 



Whiskered 
tern 

Black- headed 
gull 



Cayenne tern 

White -capped 



Red-billed tropic-bird 
Brown booby 
Kan - a- war bird 



ddy 



^^Whife 
pelican 

^ pelican 
•^^^^ African y ■^ 

^ ^ darter /^ 
African skimmer y^t^ 
Grey-headed 



Fig. -zh 
Actual species. Arrows point to replacement species or to nearest 

ecological counterparts 



Rynchops fiavirostris) . The terns of the genus Chlidonias are primarily 
lake and marsh species throughout their range. In North America 
the gulls Lams pipixcan and L. Philadelphia are purely inland species 
in the breeding season, and the tern Sterna forsteri and the pelican 
Pelecanus erythrorhynchos almost so. In South America the terns Phaetusa 
simplex and Sterna superciliaris are purely river-species. 

One hundred and eleven species of primary and thirty-two of 
secondary sea-birds have been identified by competent observers at 
sea or on some shore in the North Atlantic since 1800: a total of one 



24 



SEA-BIRDS 







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STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 25 

hundred and forty-one. Of these one primary sea-bird, Alca impennis 
the great auk, and one secondary sea-bird, Camptorhynchus labradorius 
the Labrador duck, are now extinct. Of the survivors, eighty-two 
primary and thirty secondary sea-birds actually nest, or have nested, 
on or near a North Atlantic or Mediterranean shore or a shore of that 
part of the Arctic (north of the Circle) that communicates directly 
with the North Atlantic (this brings in six arctic species: ivory-gull, 
Ross's gull, little auk, white-billed northern diver, brent-goose and 
Steller's eider). Two further species {Larus pipixcan and L. Philadelphia, 
see above) are purely inland breeders. 

Most remarkably, the number breeding on the Old World and 
New World sides is almost exactly the same. We can derive the following 
summary of breeding-species from Appendix A ; the totals include 
the two North American purely inland species, and the two extinct 
species. Doubtful ("?" in the Appendix) and casual cases are deliber- 
ately included — most of them are from tropical West Africa north of 
the equator where the breeding of the species in question seems likely 
but, owing to the scanty exploration of the coast, is not formally 
proved. 

We can see that if we add the six purely arctic breeders to those 
species which are common to both east and west sides of the North 
Atlantic, we have fifty-five, out of a total of ii6, or about half. Of 
the remaining sixty-one species, 24 breed only on the west side of 
the North Atlantic, four on the west side and in the Arctic; and six 
purely on the east side, and seven on the east side and in the Arctic. 
Those on the east side include four *sea-birds' which breed in the 
Mediterranean area but not in the North Atlantic (the crested pelican, 
pigmy cormorant, Mediterranean black-headed gull and the lesser 
crested tern) . 

The general conclusion is of considerable ecological interest, 
showing how exactly the sea-bird communities of both sides reflect 
one another. Although only about two-thirds of the members of the 
community on one side of the Atlantic are found in that of the other, 
the species comprising the remaining third 'balance each other' and 
occupy very much the same 'niches' or places in nature. Opposite 
species which pair off by occupying similar niches are grouped together 
in the list in the Appendix, p. 292. 



26 SEA-BIRDS 

A Note on Non-breeders and Casual Wanderers 

Apart from these ii6 breeders, the limbo of twenty-six primary sea-birds and 
one secondary sea-bird (the spectacled eider Somateriajischeri, which has been recorded 
twice in Norway, though it breeds on the other side of the Polar Basin) consists of 
casual wanderers, with three remarkable exceptions. These are all tubenoses 
(two shearwaters and a storm-petrel) which breed in the southern hemisphere but 
which cross the equator in large numbers to ' winter.' The most familiar of these in 
Britain is the Tristan great shearwater Puffinus gravis^ which is rather similar, and 
certainly closely related to the heavier North Atlantic or Cory's shearwater, P. 
diomedea. Incidentally we suggest confusion between the two would be reduced if 
P. diomedea were consistently called *North Atlantic shearwater' and P. gravis 'Tristan 
great shearwater' — not just 'great shearwater.' 

The Tristan great shearwater nests only on Nightingale and Inaccessible Islands, 
in the Tristan da Cunha group; possibly a few may survive on Tristan itself. The 
population remains vast, though 'farmed' by the Tristan islanders, and an annual 
penetration of the North Atlantic by off-season birds has put the species on the 
list of regular and expected visitors to both West Atlantic and East Atlantic waters, 
as well as some arctic waters of Greenland. The northward movement reaches the 
North Atlantic in May, mostly on the west side at first, but odd birds appear in Irish 
and west British waters in June and have even been seen then in the Skagerak; one of 
us saw a few already at Rockall in mid-May (1949), and they were abundant there 
and in moult by late June (1948). 

The Tristan great shearwater seldom comes close to land, and it is never 
common in British waters within sight of shore; but some distance to sea off west 
England, Ireland and the Hebrides it is always present in July and August; and 
some elements usually penetrate northabout into the North Sea, descending to the 
latitude of Yorkshire. The Tristan great shearwater is much more common than the 
Northern Atlantic shearwater in our seas; indeed, the Mediterranean race of the 
latter P. d. diomedea^ and Cory's race P. d. borealisy have each only once been taken ashore 
in Britain, although birds which may have been of Cory's subspecies have several 
times been seen at the entrance of the Channel. The only Scottish record is of one, 
seen at sea close to Aberdeen on 10 September 1947, by R. N. Winnall. Normally 
as Wynne-Edwards and Rankin and Duffey have shown, Puffinus diomedea does not get 
much farther north in the Atlantic than 50°N., and that at about 30°W. It is much 
more common on the North American coast than on that of Britain, although this 
coast is much farther from its base; 'they seem to arrive on our coasts early in 
August,' writes Bent, 'and spend the next three months with us, mainly between 
Cape Cod and Long Island Sound.' The Tristan great shearwater also probably 
reaches its greatest abundance on the North American coast, particularly in the 
area of the Newfoundland Banks, where it is known as the 'hagdon'; from here 
it extends every season along the coast of Labrador to Greenland; — it has been 
recorded near Iceland. 

The other southern hemisphere shearwater that regularly visits North Atlantic 
waters is Puffinus griseus, the sooty shearwater. It is much rarer than the Tristan 
great shearwater, though it has been seen in British waters regularly enough to be 
classed as an^autumn visitor. It breeds in New Zealand and its islands, in southern 
South America and its islands, and the Falkland Islands (in places many miles 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 27 

inland), and ranges the Pacific as well as the Atlantic; its Atlantic population is low 
compared with that of the other southern shearwater. Unlike the Tristan great shear- 
water, it probably makes its way into the North Sea by the Channel; and it is regular 
in small numbers in the Western approaches. At Rockall on 17 May 1949 J. F. 
saw none, but from 18 to 27 June 1948 R.M.L. found them always present there, 
singly and up to eight together, that is in the proportion of about one to a hundred 
hagdons. On the Newfoundland Banks, where it is in the same proportion, the 
fishermen called it the haglet. It reaches Greenland and Icelandic waters, and 
has been seen once as far north as Bear Island. 

The storm-petrel from the south is Wilson's petrel Oceanites oceanicus, which 
nests in vast numbers in the antarctic continent and on the southern islands of 
South Shetland, South Orkney, South Georgia, Falkland, Tierra del Fuego and 
Kerguelen. It disperses into, and across, the Equator in the Atlantic, Indian and 
Pacific Oceans. Wilson's petrel has been the subject of an exhaustive monograph by 
Brian Roberts (1940), who mapped the dispersal in the Atlantic month by month 
(Fig. 29, p. 1 68). Records north of the Equator are only irregular and sporadic between 
November and March, but in April the species is spread widely over the western 
half of the North Atlantic as far as Cape Cod. In May the petrels spread eastwards 
reaching from Cape Cod across the Atlantic towards Portugal and the Bay of Biscay, 
off which there is quite a concentration in June. By July there is a band of Wilson's 
petrels across the whole North Atlantic with its northern border at about 40 °N., 
but not reaching Britain. In August the eastern Atlantic petrels disappear, though 
on the west a concentration remains with its nucleus near Long Island Sound; and 
this persists in reduced population in September, by which time most Wilson's 
petrels are making their way home. In September they reappear again off Portugal, 
and the homeward stream in October runs south along the north-west coast of 
Africa, continues its line across the Atlantic to the corner of Brazil, and carries 
on mainly down the east coast of South America; in November and December the 
concentration is at its greatest in the triangle Rio de Janeiro-South Georgia-Cape Horn. 

There are only about ten records for this abundant and successful species, in 
Britain. It does not normally reach our islands, though elements cannot be within 
much more than a few hundred miles of Cornwall in June and July. Most of the 
British records are between October and December — suggesting young non-breeding 
birds, inexperienced in the ways of wind and wave. 

Among the two dozen casual sea-bird visitors to the North Atlantic undoubtedly 
the most exciting are the kings of the tubenoses — the albatrosses, whose occurences 
in the North-Atlantic-Arctic are really monuments not so much to the fact that from 
time to time the best-adapted birds make mistakes and get right out of their range, 
as to the extraordinary powers of endurance and flight of the world's greatest oceanic 
birds. Five albatrosses have strayed into the North Atlantic, four of the genus 
Diomedea, which includes the largest kinds, and one Phoebetria. All breed in the 
southern regions of the southern hemisphere. 

The most frequent in occurrence has been the black-browed albatross D. 
melanophris, of which we can trace nine records. The first of these is astonishing; 
on 15 June 1878, north-west of Spitsbergen and north of latitude 8o°N., the whaler- 
skipper David Gray shot one that is now in the Peterhead Museum; it was farther 
north than the species ever gets south, even though it nests to latitude 55°S. Another 
northerly record is from West Greenland, and others have been shot south-west 



28 SEA-BIRDS 

of the Faeroes and in the Oslo Fjord, Norway; one is even alleged to have reached 
Oesel in the Baltic. In i860 (Andersen 1894) a female black-browed albatross 
turned up among the gannets of Mykinesholmur in Faeroe, and came to the cliff 
every season with them until 1 1 May 1894, when it was shot by P. F. Petersen. For 
many years the only British record was of one which was caught exhausted in a 
field near Linton, Cambridgeshire, on 9 July 1897; but on 14 May 1949 an im- 
mature albatross which was probably of this species was seen at the Fair Isle, between 
Orkney and Shetland. It was first noticed soaring off the south face of the Sheep 
Craig, the famous landmark on the east side of the island, and obligingly glided over 
George Waterston, G. Hughes-Onslow and W. P. Vicary, who got a fine view of it 
(Williamson 1950, 1950b). Further, in September 1952 one was picked up alive 
in Derbyshire (Edmunds, 1952; Serventy, Clancey and Elliott, 1953). 

No other albatross has been certainly seen in Britain: a record of the yellow- 
nosed albatross from the Lincolnshire-Nottinghamshire boundary on 25 November 
1836 is not admitted to the British list. This species, D. chlororhynchos^ has been 
certainly obtained, however, in south Iceland, at the mouth of the St. Lawrence 
river, in the Bay of Fundy (New Brunswick), and in Oxford County, Maine. A 
record of D. chrysostoma from Bayonne in France* may possibly refer to this species, 
for D. chlororhynchos and D. chrysostoma are extremely similar, and almost impossible 
to distinguish in the field. D. chrysostoma, the grey-headed albatross, has, however, 
certainly been recorded once in the North Atlantic — from South Norway in 1837 
(or 1834). The light-mantled sooty albatross Phoebetria palpebrata, a relatively small 
species which breeds on sub-antarctic islands, has been recorded from Dunkirk, 
France*. The greatest of all the albatrosses, the wandering albatross Diomedea exulans, 
has been taken, in France (Dieppe), Belgium (Antwerp) and on the Atlantic coast of 
Morocco ; this magnificent animal has a wingspread up to 11^ feet and may weigh 
seventeen pounds or more; we can imagine the excitement of those humans who 
encountered these South Atlantic wanderers on their North Atlantic wanderings! 

Sometimes these wanderings may end in queer places; for instance, F. J. Stubbs 
(19 1 3) found an albatross that he judged to be D. exulans hanging among the turkeys 
of Christmas 1909 in a game-dealer's shop in Leadenhall Market. When he saw it 
'the bird appeared quite fresh, and bright red blood was dripping from its beak.' 
There was no indication whence it had been obtained. 

Unidentified albatrosses have been seen at sea west of Spitsbergen on 2 May 
1885, by the Captain David Gray who shot the 1878 black-browed albatross; 
off the mouth of Loch Linnhe, West Highlands of Scotland, in the autumn of 1884 
by W. Rothschild; and twenty miles north-west of Orkney on 18 July 1894, by 
J. A. Harvie-Brown (1895). 

Apart from the three regular non-breeding summer visitors and the albatrosses, 
at least six other tubenoses have wandered into the North Atlantic from the South, 
or from the Pacific. The Cape pigeon Daption capensis, has been recorded from France*, 
Holland and Maine, but the three British records have been rejected from the official 
list on the grounds that sailors have been known to liberate captured specimens 
in the Channel. Quite probably they are valid. Peale's or the scaled petrel Pterodroma 
inexpectata, has once been taken in New York State. Pterodroma neglecta, the Kermadec 
petrel, has been once found dead in Britain (on i April 1908 near Tarporley in 
Cheshire). One Trinidad petrel Pterodroma arminjoniana, was driven to New York 

* Not included by N. Mayaud (1953) in his List of the Birds of France 



STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 29 

by the hurricane of August 1933, and possibly this close Atlantic relative of the 
Kermadec petrel may cross the equator fairly often, as it breeds on South Trinidad 
Island (only), which is fourteen hundred miles south of the equator, surely no very 
great distance for a petrel. One collared petrel Pterodroma leucoptera, a Pacific species, 
was shot between Borth and Aberystwyth in Cardiganshire, Wales, at the end of 
November or the beginning of December 1889. The last wandering tubenose is the 
black-bellied storm-petrel Fregetta tropica, a sub-antarctic species which was first 
collec ted off the coast of Sierra Leone and has also been taken in Florida. It seems 
likely that this last species may cross the equator fairly regularly, at least as far as 
the Tropic of Cancer. 

One Pelecaniform wanderer has crossed the equator into the North Atlantic from 
South Africa — the Cape gannet Sula capemis, which may reach north to the Canaries. 

From the western United States the California gull Larus californicus (which may 
be a race of the herring-gull, see p. 38) winters fairly regularly to Texas, and thus 
(in our definition) to the North Atlantic region. Another gull which enters the North 
Atlantic, from more distant breeding-grounds, is the great black-headed gull, 
Larus ichthyaetus of the Black Sea and farther east, which has reached Madeira and 
Belgium and has been seen in Britain about eight times. 

Four exotic terns have wandered into the North Atlantic. The South American 
Trudeau's tern Sterna trudeaui, has once reached New Jersey. On the east side 
Sterna balaenarum, the Damara tern of South Africa, has migrated across the equator 
as far as Lagos in Nigeria. Thalasseus bergiiy the swift tern, breeds on the west coast 
of South Africa north to Walvis Bay, whence occasional individuals may sometimes 
pass north across the equator. The elegant tern Thalasseus elegans, of the Gulf of 
California, has accidentally reached Texas. And finally Gygis alba, the tropical, 
white, almost 'transparent' fairy tern breeds north in the Atlantic to Fernando 
Noronha, and therefore probably occasionally operates across the two hundred 
miles that would bring it to the North Atlantic, though there is so far no formal 
record of this. It has a wide distribution in all tropical seas, but is very much attached 
to, and does not often fly far from, its breeding-grounds; nevertheless R. C. Murphy 
(1936) ponders: 'Since there are seasons when powerful southeast trade winds blow 
from Fernando Noronha across the equator almost as far as the mouth of the River 
Orinoco, speculation offers me no clue as to why Gygis has not succeeded in jumping 
the next gap and establishing itself in the West Indies.' 

The remaining wanderers are from the North Pacific — auks from that cradle 
of the sub-order of auks. Aethia pusilla, the least auklet, has not actually reached the 
Atlantic, but one was found 'halfway' from the Pacific to the Atlantic, in the Mackenzie 
delta in May 1927. The ancient murrelet Synthliboramphus antiquus hdi&hQQnionnd three 
times in the Great Lakes area, but no farther east. Aethia psittacula, the paroquet 
auklet,* has actually reached the Atlantic by turning up in, of all places, 
Sweden: in December i860 one was captured in Lake Vattern! If the least auklet 
has not reached the Atlantic, its congener Aethia cristatella, the crested auklet, has, 
for even if we reject (as most do) the alleged Massachusetts record, we must accept 
that of 15 August 1 91 2 when one was shot north-east of Iceland. Finally Lunda 
cirrhata, the tufted puffin, was obtained by the great naturalist Audubon in Maine: 
other records from the Bay of Fundy and Greenland are erroneous. 

*Ludwig Kumlien (1879) may possibly have seen this species off North Labrador, 
see Finn Salomonsen (1944). 




Fig. 2c 
Bathymetrical sketch-chart of the Atlantic Ocean 



CHAPTER 2 

EVOLUTION AND THE NORTH 
ATLANTIC SEA-BIRDS 



GEOLOGISTS DIFFER in their opinions of the origin of the Atlantic 
Ocean. The followers of the geomorphologist Alfred ^Vegener 
believe that it is a real crack in the earth's crust whose lips have drifted 
away from each other, and this opinion is lent verisimilitude by the 
neat way in which the east coast of the Americas can be applied to, 
and will fit with extraordinary exactitude, the west coast of Europe 
and Africa. It must be stated that, while the present opinion of most 
geographers is that the resemblance of the Atlantic to a drifted crack 
is purely coincidental, this is not shared by all students of animal 
distribution and evolution, some of whom, find the Wegener theor)^ the 
most economical hypothesis to account for the present situation. 

Whatever the truth is, there is no doubt that the boundaries of the 
Atlantic, and their interconnections, have varied considerably; thus half- 
way through the Cretaceous Period, about ninety million years ago (dur- 
ing this long period nearly all the principal orders of birds evolved), 
there were bridges between Europe, Greenland and Eastern North 
America cutting the Arctic Ocean froml the North Atlantic 
completely; and from then until the late Pliocene — perhaps only 
two million years ago — there was no continuous Central American 
land bridge, but a series of islands. 

Our present knowledge of the tree of bird evolution owes much 
to Alexander Wetmore and his school, who have so notably added 
to our knowledge of fossil birds during the last twenty years, especially 
in North America. Birds do not appear very frequently in the sedi- 
mentary rocks — their fossil population does not generally reflect 
their true population in the same way as that of mammals is reflected. 
However, if land-birds are rare in the beds, water-birds are relatively 



32 SEA-BIRDS 

commoiij and the periods and epochs in which all our sea-bird orders, 
and many of our sea-bird families and genera, originated are quite well 
known. A recent paper by Hildegarde Howard (1950), of the school 
of Wetmore, enables us to show a diagrammatic family tree of birds 
(Fig. 3), with special reference to sea-birds, and to collate its branching 
with the approximate time scale of the epochs, so cleverly established 
by geomorphologists in recent years from studies of sedimentation-rate 
and the radioactivity of rocks. It will be seen that the primary radia- 
tion of birds and the great advances into very different habitats 
consequent upon the first success of the new animal invention — 
feathered flight — took place in the Cretaceous period, the first bird- 
like feathered animals having been found as fossils in Jurassic deposits 
of the previous period, over a hundred and twenty million years old. 
In the Cretaceous period — the period of reptiles — ostriches were 
already foreshadowed, as were grebes and divers, and the pelican-like 
birds, and the ducks. 

In the Cenozoic period — the period of mammals — the radiation of 
birds into all nature's possible niches continued rapidly, especially 
in the first two of its epochs — Eocene and Oligocene — from sixty to 
thirty million years ago. In these epochs grebes can be distinguished 
from divers, and a bird of the same apparent genus {Podiceps, or, as 
the North Americans have it, Colymbus) as modern grebes has been 
found. Gannet-boobies of the modern genus Sula have been found in the 
Oligocene, as have cormorants of the modern genus Phalacrocorax. 
The only penguin fossils known are later — of Miocene age — but 
it seems probable that they share a common stem with the tube- 
noses, which would mean that their ancestors branched off in the 
Eocene. The tubenoses diversified in the Oligocene — from this epoch 
we have a shearwater of the modern genus Puffinus; and from 
the Miocene Fulmarus and albatrosses. The ducks started their main 
evolution in the Cretaceous, and by the Oligocene we find modern 
genera such as Anas (mallard-like) and Aythya (pochard-like); in 
the Pliocene we have Bucephala (Charitonetta) — one of the tribe of 
sea-ducks. 

For the Lari-Limicolae, the order which includes waders, gulls 
and auks, the fossil record is rather indefinite, mainly owing to the 
difficulty of distinguishing the present families by bones alone. How- 
ever, we know that the auk family was early — an Eocene offshoot; 
that the waders and gulls diverged in the Oligocene; and that the gulls, 
terns and skuas probably diverged in the Miocene — which means 



E V O L U T I O N 



33 




ySTEGAKOPODES 



iBo 



150 120 60 40 30 

MILLIONS OF YEARS 



o o 



PALAEOGNATHAE (Ostriches, 

Rheas, Cassowaries, Emuit, 

Kiwis, Tinamous) 
G^F//1£ (Divers) 
PODICIPEDES (Grebes) 
PELECANIDAE (Pelicans) 
Morus (Gannets) \ct TT tt-> \ T? 
Sula (Boobies) / ^ U i.1 UAL 

PHALACROGORACIDAE (Gor- 
morants) 

ANHINGIDAE (Darters) 

PHAETHONTIDAE (Tropic- 
Birds) 

FREGATIDAE (Frigate-Birds) 

SPHEjXISCI (Penguins) 

DIOMEDEIDAE (Albatrosses) 

P:Sh':"a™.5„,}PROCELLARnNAE V rUBINARES 

HYDROBATINAE (Small 

Petrels) J 

PELEGANOIDIDAE (Diving 

Petrels) 
Branta (Black Geese) 
Anser (Grey Geese) 
Anser {Chen Group) 
Cygnus (Swans) j- 

n.ndrocygna, etc. (Tree-Ducks) j'ANATIDAE 
Anas, etc. (River-Ducks) 
Aythya, etc. (Pochards) 
— ^ Mergus, etc. (Sea-Ducks) 
Other Duck Tribes 
.\NHIMIDAE (Screamers) 

FALCONES (Diurnal Birds of 

Prey) 
GRESSORES (Herons, Storks. 

Ibises, Flamingos)* 
G.-lZ,Z,/(Game-BTrds) 

GRUES (Cranes, Rails and 

Bustards) 
CHARADRIIDAE (Waders) 
STERGORARILXAE (Skuas) 

LARIDAE (Gulls and Terns) 
RYNGHOPINAE (Skimmers) 
ALCIDAE (Auks) 
STRIGES (Owls) 
J PA 'y'SERES (Perching and Singing 
Birds) 



yA.ySERES 



LARO- 
LIMICOLAE 



10 



*Mayr and Amadoo (1951) placf these hi an 
order PHOEMiCOPTERI nf«r*r Anwrei. 



Fig. 3 
Diagrammatic family tree of sea-birds, mainly after Hildegarde Howard (1950) 



34 SEA-BIRDS 

that an important part of the adaptive radiation of this order was 
comparatively late. One of the early auks, the Pliocene Mancalla of 
California, out-penguined the great auk, Alca [Pinguinus) impennis, for it 
had progressed far beyond it in the development of a swimming wing. 

According to Howard (1950) a few living species of birds have 
been recorded from the Upper Pliocene, but large numbers of modern 
forms occurred in the Pleistocene. Of course in the Pleistocene the 
oceans approximated very closely to what they are today, with the 
Central American land-bridge closed, the Norwegian Sea wide open 
between Arctic and Atlantic Oceans, the Mediterranean a blind 
diverticulum of the North Atlantic. We need this picture as a back- 
ground to a consideration of the North Atlantic's present sea-bird 
fauna, for wc shall find that it has few sea-bird species of its own, 
and only two genera; for the primary sea-bird species which now 
breed in the Atlantic (and Mediterranean) and in the neighbouring 
parts of the Arctic, and nowhere else in the world, are no more than 
twelve : the Manx shearwater Fuffinus puffinus* ; the very rare diablotin 
and cahow of the West Indies and Bermuda {Pterodroma hasitata and 
P. cahow) ; the storm-petrel Hydrobates pelagicus; the North Atlantic 
gannet Sula bassana; the shag Phalacrocorax aristotelis; the lesser black- 
back Larus fuscus; the great blackback L, marinus; the Mediterranean 
gulls L. melanocephalus and L, audouinii; the Sandwich tern Thalasseus 
sandvicensis; the razorbill Alca torda, the puffin Fratercula arctica; besides 
the extinct Alca impennis, the great auk. The two present genera 
peculiar to the North-Atlantic-Arctic are Hydrobates and Alca, 

The sea-birds which qualify by birth and residence to be members 
of the North Atlantic fauna (excluding purely Arctic and Mediter- 
ranean species) include thirteen tubenoses, seventeen cormorant- 
pelicans, fourteen gulls, nineteen terns, two skimmers, four skuas and 
five auks (besides various secondary sea-birds, notably about eighteen 
ducks, three divers and two phalaropes). If we are to understand 
how these have got into the North Atlantic we should analyse the 
present distribution of the sea-bird orders and groups as between the 
different oceans. 

The most primitive group of sea-birds, yet the most specialized, 
is that of the penguins. The Sphenisci have fifteen species in all, 

* Murphy (1952) has recently united as races of this species several Australasian 
and Pacific forms hitherto considered full species, and has suggested that the species 
may date from the Oligocene period when the Mediterranean communicated 
directly with the Indian Ocean. 



EVOLUTION 35 

of which eight breed in the South Pacific, seven in the Antarctic 
Ocean, five in the South Atlantic and two in the Indian Ocean. One 
(and one only) reaches the Equator, and thus the North Pacific, at 
the Galapagos Islands. No live wild penguin has ever been seen in 
the North Atlantic. * It seems certain that the evolution of this order 
of birds has taken place in Antarctica and in the neighbouring sectors 
of the South Pacific. 

The great order of Tubinares the albatrosses, petrels and shear- 
waters, probably originated in what is now the South Pacific. 
Nobody knows exactly how many species belong to this order, as 
there is a good deal of disorder in the published systematics of this 
very difficult group ; but the number is certainly eighty-six, and may be 
over ninety Of these fifty-four breed in the South Pacific, twenty-seven 
in the Antarctic, twenty-five in the North Pacific, twenty-four in the 
South Atlantic, seventeen in the Indian Ocean, thirteen in the North 
Atlantic, three in the Mediterranean, and only one, the fulmar, in 
the Arctic Ocean. 

The Steganopodes are an order which is particularly well repre- 
sented in the South Pacific and Indian Oceans. The pelicans, gannets, 
cormorants, darter, tropic- and frigate-birds number fifty-four 
species in all. Thirty-one breed in the South Pacific. Twenty-eight 
breed in the Indian Ocean. The North Pacific has twenty-three, the 
South Atlantic twenty, the North Atlantic sixteen, the Mediterranean 
six, the Antarctic three, and the Arctic two. The present distribu- 
tion suggests that the order radiated from what is now the East 
Indian region — from south-east Asia or Australasia. 

In the order Laro-Limicolae the family Chionididae, two curious 
pigeon-like sheathbills, Chionis, are found in Antarctica; and one also 
breeds in the South Atlantic and South Pacific. 

In the family Laridae the gulls (subfamily Larinae) number 
forty-two. In the North Pacific sixteen of these breed, in the North 
Atlantic fourteen, in the Arctic eleven, in the South Pacific nine, in 
the Indian Ocean six, in the South Atlantic five, in the Mediterranean 
five, in the Antarctic two. Besides these two breed inland only in 
North America, one inland only in South America, and three inland 

* Apart from nine king-penguins, Aptenodytes patagonica, introduced into the Lofotens 
and West Finmark, Norway, in 1936; most soon disappeared or died, but at least 
two survived on the coast until 1943 and one to 1944 (G. Schoyen in K. Curry- 
Lindahl, 1947, and W. E. Glegg, 1949). Some macaroni and jackass penguins 
{Eudyptes chrysolophus and Spheniscus demersus) were also released in the Lofotens in 
1938 but these were never seen again. 



<26 SEA-BIRDS 

only in the Palearctic Region. This appears to be the only group of 
sea-birds whose evolutionary radiation may have taken place from 
the north; the Arctic and neighbouring parts of the North Pacific 
and Atlantic appears to be the origin of the gulls. The terns (sub- 
family Sterninae) number thirty-nine, of which twenty-three breed 
in the North and twenty-two in the South Pacific, nineteen in the 
Indian Ocean, nineteen in the North Atlantic, fifteen in the South 
Atlantic, ten in the Mediterranean, two in the Antarctic, two in the 
Arctic and one inland only in South America. The radiation of terns 
appears to be pretty general over the world's seas, and they may 
have originated in the tropics, perhaps in the Indian Region. The 
skuas (subfamily Stercorariinae) have only four species, one of which 
{Catharacta skua, the great skua) has its breeding-headquarters in 
the Antarctic; it also breeds in the South Pacific, South and North 
Atlantic. The other skuas have an arctic breeding-distribution which 
extends into the North Pacific and North Atlantic. The three skimmers 
Rynchops belong to a separate family, Rynchopidae; North Atlantic, 
South Atlantic and South Pacific each have two; the Indian Ocean 
has one. Some workers regard them as all of one species. 

The family Alcidae (the auks) take the place in the north of 
the penguins of the south. Undoubtedly their origin has been in or 
not far from the Bering Sea. Of the twenty-two species, sixteen 
belong to the northern part of the North Pacific, twelve to the Arctic 
Ocean north of the Circle, and six to the northern part of the North 

Atlantic. 

This concludes the list of sea-birds belonging to groups of super- 
family or higher status whose evolution has been marine. There are 
several further (secondarily marine) groups which contain sea-birds, 
or part-time sea-birds; thus all four members of the order Gaviae 
the divers, breed in the Arctic, and North Atlantic and Pacific 
regions, and winter at sea on the coasts of the oceans. Many of the 
twenty species of grebes, order Podicipedes, are marine outside 
the breeding-season, and six of them visit the coasts of the North 
Adantic at that time. Among the geese and ducks many (see Appendix, 
p. 295) are partly marine, and some {e.g. eiders and scoters) are 
largely marine in the breeding — as well as in the ofF-season: two eiders 
and three scoters breed in the North Atlantic-Arctic. Among the waders 
(Charadriidae) the subfamily Phalaropinae contains only three 
members, all of which breed in the Arctic, North Adantic and North 
Pacific, and two of which winter in the open sea. 



EVOLUTION 37 

If we ignore these secondary sea-birds, and consider the 267 
species of the primary marine groups, we find that the hierarchy is 
this: South Pacific 128 (51 per cent.) ; North Pacific 107 (40 per cent.) ; 
North Atlantic 74 (28 per cent.); South Atlantic 73 (27 per cent.); 
Indian Ocean 73 (27 per cent.); Antarctic 44 (16 J per cent.); Arctic 
31 (11 J per cent.); Mediterranean 24 (9 per cent.); and purely inland 
only 7 (2 J per cent.). 

It can be seen that the North Atlantic, with its seventy-four 
species, is much lower than either half of the Pacific than would appear 
warranted by its area. There is not the faintest hint, from the radiation 
of any of the sea-bird groups, that either North or South Atlantic has 
been the arena of any great evolutionary changes. The Atlantic has 
been colonised from without; by penguins from the Antarctic; by 
petrels from the South Pacific; by pelecaniform birds and terns 
probably from the Indian Ocean; by gulls and auks from the Arctic. 
The North Atlantic and the immediately neighbouring parts of the 
Arctic have but two present sea-bird genera and only thirteen species 
of their own. We need not be surprised at this indication that the 
Atlantic's bird fauna is derived from that of other oceans if we accept 
\Vegener's theory of the origin of the Atlantic; but whether the Weg- 
ener theory is true or not it is quite clear that the North Atlantic 
has not been the home in which any important group of sea-birds has 
evolved. This is not to say that there has been no sea-bird evolution 
in the North Atlantic; but it has not usually gone beyond the differ- 
entiation of species. Of this it has, indeed, much to show. Some of 
the classic examples which E. Mayr (1942) has discussed are North 
Atlantic species. Mayr's thesis is that one species can only become 
two after it has been differentiated geographically. He opposes the 
notion which has found favour in some quarters that speciation may 
occur by ecological differentiation or by the differentiation of behaviour. 

So far the available evidence appears to uphold Mayr's view — 
at all events, for birds. During the present century much systematic 
work in the description and measurement of birds has been conducted 
in American and European museums, and much practical and theoreti- 
cal work on evolution has also been done. But it needed the persuasions 
of Mayr and JuHan Huxley (1942), amongst a few others, to collate 
the work of the systematists and the evolutionary zoologists. Sea-birds 
lend themselves to evolutionary study because they are so largely 
confined to coasts for breeding purposes. This makes their distribution 
often linear rather than of the ordinarily spatial two-dimensional 



38 SEA-BIRDS 

type; and this linear distribution makes it easy to apply Huxley's 
concept that the characteristics of animals tend to grade from one 
part of their range to another in an orderly way. Some of these grada- 
tions had been recognised long before Huxley thought of the word 
"cline" because they are adaptations to the environment. For instance 
Bergmann's Rule states that from the warmer parts of an animal's 
distribution-area to the colder parts there tends to be an increase in 
its size. Thus the puffins, black guillemots and eider-ducks of the 
Arctic are considerably bigger than those of Britain. The main adaptive 
reason for this is that larger animals have less surface in proportion 
to their weight, and consequently heat is not lost from them (if warm- 
blooded) so rapidly as it is from small animals. Another rule, Allen's 
Rule, states that warm-blooded animals of cold climates tend to have 
their heat-radiating surfaces decreased by a reduction in size of their 
extremities and limbs such as ears, tails, necks, legs and noses. There 
is also a general tendency (Gloger's Rule) for animals to become 
darker as humidity increases. 

If we examine those sea-birds which are widely distributed, we 
find clines in various characteristics, notably in size, i.e. total size, 
and also size of limbs and extremities, beak-length, wing-length, 
etc., and in colour. There are also clines in shape; for instance the 
fulmars of the north-east Atlantic have very thick bills, those of 
Baffin Island rather more slender bills, those of the North Pacific 
more slender bills still, and those of the Antarctic very slender bills 
indeed. No sea-bird is arranged quite evenly in its geographical 
distribution. Just as the distribution in space is never even, so are the 
gradations in character never even. From one part of the geographical 
distribution of a species to the other, change often occurs more as 
a series of steps rather than as continuous ramp. 

Most working ornithologists today will agree that there are more 
subspecific names about than a true understanding of bird evolution 
requires. It is the species which has reality and significance. In this 
book we have tried to be sparing in the use of subspecies, and have 
rejected some that appear in many current text-books. Nevertheless, 
a study of the geographical races of the species of the North Atlantic 
sea-birds will lead us to examine here some of the more fascinating 
examples of geographic differentiation. The classic example among 
the sea birds is the chain of the Larus argentatus and fuscus group, the 
herring-gulls and lesser blackbacks, which may include some birds 
which are regarded as separate species, e.g. the California gull L. 



EVOLUTION 39 

calif amicus, and the so-called 'Iceland' gull, or better the Greenland 
herring-gull, L. glaucoides or leucopterus. The relationships of this 
superspecies (Fig. 4a) were first worked out by B. Stegmann 
(1934): we have included the results of subsequent systematic work 
in this map (Fig. 4b) and in the discussion which follows. 

It will be seen that the subspecies is composed of three chains 
of subspecies which unite in Central Siberia, where the resident 
breeding subspecies is Birula's herring-gull Larus argentatus birulai. 
The two northerly chains link round the Polar Basin, the two end 
links of one overlapping with the two end links of the other. Where 
they overlap, the two races of one chain-end are 'herring-gulls,' of 
the other 'lesser blackbacks.' These behave as different species. It 
can be found convenient to make the 'species' separation in the 
chain, between the two races birulai and heuglini, thus calling the latter 
Larus fuscus heuglini (it is the first really dark-mantled gull in the chain) . 
This is more practical than splitting the chain into argentatus dind fuscus 
in the Bering Strait area, though this is probably the place of origin 
of the ancestral gull that gave rise to the whole chain ; for if all the 
palearctic group were fuscus some confusion would surround the 
light-mantled Mediterranean forms. 

Special comments can be made on various members of the chain. 
In the zone of overlap in Western Europe the herring-gulls are 
distinguished from the lesser blackbacks not only by form but by many 
habits. The lesser blackbacks breed often inland on moors, and when 
coastal tend to colonise flattish ground set back from the cliff-tops 
beloved of the herring-gulls. While the herring-gulls are dispersive 
in winter, the lesser blackbacks are almost entirely migratory, winter- 
ing south of all but their most southerly breeding-places, though some 
of the dark L. f fuscus of Scandinavia winter in Britain, and recently 
a minority of the British race L. f graellsii has 'revived' an old habit 
of wintering in England, especially in Cheshire and Lancashire. 
Both species are also extending their breeding-range north; L. a. 
argentatus has colonised east and north-east Iceland since 1909, and a 
herring-gull of this or the Scandinavian race omissus was breeding on 
Bear Island in 1932, though not 1948. The graellsii lesser blackback 
has established itself in south Iceland since about 1925, and a group 
intermediate between graellsii and fuscus in Denmark since 1922. 

The North American situation is of great interest. As the herring- 
gulls range north-east they become generally paler in colour. The 
much-discussed Kumlien's herring-gull L. a. kumlieni was for a long 



<i.CA.lifomtcus 

Califorauj gull 

greenish.- 
^ yellow 

tnediuiri 
dark 



a..smitlisonianu5 

American n.g. 

flesh 



very 
ligKt 



A tKayeri 
Thayer's gull 



flesh 



markedly 
pale 



Vega herringguU 

bluish 
flesh 

markedly, 
dark 



a.kumlieni 

5 ^ 
Kumliensgull 

flesh. 



very 



pale 



glaucoides 

Iceland gull 
paleflesh 

extremely 
pale 



A. birulai 

9 
Birulds gull 

dull yellow - 
flesh 

medium, 
light 



f. graellsu 

17 
British l.b.b. 

yellow 

extrernely 
dark 



a.argentalus 

2 
Herring-gull 

flesh 
markedly 



a omissus 
I 
Scandinavian kg. 



V. fuse as 
"^ 16 " 
lesserhladhack 



yellow 

medium 
light 



briaht 
yellow 

almost 
black 



f. heuglini 

14 
Heaglins gull 
yellow 

dark 



_f,antelius 

15 
Siberian l.b.b. 

yellow- 
orange 

dark 



a.mongoltcus 

to 

Hongoliank.-g. 

yellow- 

flesh 

medium 
light 



a.csiccriinans 
II 

Yellow- legged L-g. 
yellow 

light 



a.michahelles 
12 

Mediterranean h.g 
yellow 

medium 



a.a.tlantis 
13 

Madeiran h.g. 
maize 
yellow 

medium 
dark 



Fig. 4 

Breeding distribution and relationships of all subspecies of Larus fuscus, 

L. argentatus and related forms. 

a Diagram of forms, with leg and mantle-colour 




Fig. 4^ 
Broken line: in Eurasia, L. fuscus; in North America southern Hmit of 
possible area of overlap between L. calif ornicus and L. argentatus smithsonianiis. 
Fig. 4a. opposite, gives the key to the numbered forms. 



42 SEA-BIRDS 

time held to be a hybrid between the 'Iceland' gull of Greenland and 
L. a. thayeri^ Thayer's gull of the Canadian Arctic and Thule corner 
of north-west Greenland. But there seems no doubt that it is a valid 
race (Taverner, 1933) with its own discrete breeding-distribution 
in southern Baffin Island, though on the western marches of its distri- 
bution there are apparently some forms intermediate between it and 
thayeri (Horring, 1937) and colonies off south-west Baffin Island have 
been described as mixed (Soper, 1928). 

The palest of all the herring-gulls is the 'Iceland' gull. Unquestion- 
ably this extremely pale bird, with pale flesh legs, is a herring-gull, 
and conspecific with the other herring-gulls of North America. Reports 
of its breeding in the Canadian arctic archipelago are due to confusion 
with thayeri; there is no evidence whatever of its overlapping with this 
or any other subspecies of L. argentatus anywhere; and its similarity 
in size, structure and plumage is obvious. It is just a very pale kind of 
herring-gull; and at the same time happens, through convergence, 
to be extraordinarily similar to, though smaller than, the glaucous 
gull. * It is entirely confined to Greenland, breeding north to Melville 
Bay on the west (this inhospitable coast separates it from thayeri) and to 
Kangerdlugssuaq (at the south end of the Blosseville coast) on the 
east. Evidence of its breeding farther north in east Greenland, and 
elsewhere (e.g. Franz Josef Land, Novaya Zemlya) is quite unsatis- 
factory, and probably due to confusion with the glaucous gull; on 
Jan Mayen it was stated by F. Fischer to be as abundant as the glaucous 
gull in 1882-83, and to be nesting on low ledges, but it has not been 
proved to breed there since. 

In a complex situation, such as this, a confusion of scientific 
names is to be expected. In other cases it is often found that the 
vernacular name is less equivocal, and certainly more stable, than the 
scientific name! Such is not the present case, however; for the name 
'Iceland gull' makes confusion worse confounded. It has never bred 

*It is an interesting and additionally confusing fact that the "Iceland" gull 
resembles the larger glaucous gull, L. hyperboreus (with which it overlaps throughout 
its breeding-range), more than it resembles the neighbouring subspecies of its own 
species ; and that the western forms of the fuscus group resemble in plumage the 
larger great blackback L. marinus (with which they overlap geographically) more 
than do the eastern argentatus herring-gulls (with which they also overlap). The 
glaucous gull and great blackback are closely related to each other, but are distinct 
species whose breeding range considerably overlaps; within the overlap hybridiza- 
tion is not unknown, though extremely rare. Hybridization between herring-gulls 
and lesser blackbacks in the zone of their overlap is also not unknown, though rare. 
Hybridization between glaucous gulls and herring-gulls has also been recorded. 



EVOLUTION 43 

in Iceland. Honing and Salomonsen (1941) have already used the 
English name Greenland Gull to describe it, and regard it as a race of 
Lams argentatus. We commend to our readers, and to the compilers 
of the Lists of the American and British Ornithologists' Union : 

the Greenland Herring-Gull, 
Lams argentatus glaucoides {= L. a. leucopterus) 

Among the North Atlantic sea-birds are others whose species have 
differentiated geographically and whose range-end populations have 
become different enough to occupy the same geographical area — 
but separate ecological niches, and thus preserve their identity. For 
instance, it is probable that the ring-billed gull Larus delawarensis, of 
North America, and the common gull of the Old World, L. canus, 
have not long since shared a common ancestor, though a subspecies 
of the common gull, which has probably spread across the Bering 
Straits from the Old World, now occupies Alaska and parts of the 
Canadian North- West, where it overlaps with the western element 
of the ring-billed gull (Fig. 5). Here the two act as different species. 
The glaucous gull and the great blackback, which overlap in eastern 
North America, Iceland and parts of the European Arctic (Fig. 6) 
may be not long ago descended from a common ancestor. They very 
rarely hybridise. How the three species of terns — the arctic, common 
and Forster's — which are very closely related, arrived at their present 
distribution (Fig. 7, p. 46) is difficult to imagine at this stage of their 
evolution, but they all may be descended from a common tern of 
north-east Asia or an arctic tern of the North Pacific — from which 
part of the world the species has probably spread, differentiated and 
overlapped. 

Various suggestions could be made as to the origins of the two 
guillemots, the common and Briinnich's guillemot (Fig. 8). Possibly 
the original guillemot was a common guillemot {Uria aalge) type 
which got divided into two subspecies in the Atlantic and Pacific 
by the Ice Age, but not before it had had time to give rise to an arctic 
race adapted to the harder life. After the Ice Age, with the ameliorat- 
ing conditions, perhaps both the Atlantic and the Pacific guillemots 
began pushing north again, this time to meet and overlap with their 
arctic descendant, which, meantime, had differentiated sufficiently to 
offer no direct competition. It is interesting to note that the most 
arctic of the common guillemot races, Uria aalge hyperborea of Iceland, 
Novaya Zemlya, and Lapland, has a very thick bill and a considerable 
resemblance to Briinnich's guillemot, with which it, however, does not 



44 



SEA-BIRDS 




Fig. 5 
Breeding distribution of Larus canus,. the common gull, and the closely 
related L. delawarensis, the ring-billed gull 

interbreed, nor apparently compete. Perhaps it is recapitulating some 
of the early stages in the origin of Briinnich's guillemot. To some 
extent Briinnich's guillemot, with its razorbill-like beak, appears to 
replace the razorbill in the arctic, where it may occupy the same 
ecological (feeding and breeding) niche in relation to the common 
guillemot as the razorbill does in relation to that bird in the south 
part of the common guillemot's range. 

The student of variation will find much material for his researches 
among the North Atlantic sea-birds. Several species of North Atlantic 



EVOLUTION 



45 




Fig. 6 
Breeding distribution of a group of closely-related gulls: Larus occidentalis , 
the western gull: L. glancescens, the glaucous- winged gull; L. schistisagus , the 
slaty-backed gull; L. hyperboreus, the glaucous gull; and L. marinus, the great 
black-back. Areas of overlap shaded. Black areas in Canadian Arctic 
represent outpost breeding-places of L. marinus 



birds, notably the common guillemot, the three smaller skuas and the 
fulmar, are polymorphic or dimorphic. They exist in several so-called 
phases. Some common guillemots have a white ring embracing their 
eye from which a white line runs back towards the back of their heads. 
These are called ^bridled' guillemots, and were for long actually 
thought to be of a different species. The phases of the skuas range 



46 



SEA-BIRDS 



^> 



^/ 



^orsteri^ 



M^ 



__ •Virgin Is. 
.Uommica. 



>fc\ 



^ 




^.^5."^"^ 



Jo> 





SQi^ 


— ^% 


w/r:v:y: ;■:::; 


^n\j' 









/ 




J 


-<- 


/^^ 






1 r/ 


hi r undo 






^y^'^Vm 


h^ 






^^ 


J 


io^ 


JoT 1 


^: lO* 


---^ 



iV^"-~^ 






^^1 — 



' 1 






Fig. 7 
Breeding distribution of three closely-related terns: Sterna hirundo, the 
common tern; S. paradisaea, the arctic tern; S.forsteri, Forster's tern. Areas 
of overlap shaded. S. h. turkestanica is a doubtful subspecies 



from very light phases with yellow over their ears and the back of their 
necks, white throats and bellies, to those which are almost uniformly 
brown. The breeding fulmar population of Britain, the Faeroes, Ice- 
land, Jan Mayen and West Greenland are all light-coloured with 
white bellies, necks and breasts, but in Baffin Island, Spitsbergen and 
Franz Josef Land the fulmars are nearly all very dark coloured. 
Between the light forms of Britain, etc., and the dark forms of Spits- 
bergen, there are a number of puzzling intermediates, most in evidence 



"Ks 



EVOLUTION 

.oei „ 



J5t. 



s^> 



^l 



aalge 



'J-geTnortm<i- 



^ 



aalge axil^e aalge spiloptera ' 



•^ 



"^ 



«fc> 



iQ. 



^axilge udermedi 




aalge albionis 



ao- 



47 



^ 


j^ 


fljw^--'^^^^^^- ^ 


■es> 


rW'-^ 


P^^^^ 


"v ^ 4v 


\ 


^ 


fe 


X 


V 


£\ 


^^ 


L \ "^ 


1 


^ 
.* 


1^ 


r \ 


fe 


^^v^JS.X 


•(1 


Vj,^ 'w '4y 'so' '«o" 


'so' * 


/^ 


.^5^ 


($> 


1 


/ 


\#\^ 


W^ ( > 


\' 


^1 


c& 


•^aalge hyperborea 


/ 


m^ 


"^S^t^ 


_^ 


/^ 



Fig. 8 
Breeding distribution of two closely-related guillemots or murres: Uria 
W^^, the common guillemot ; and U.lomvia, the arctic guillemot (Briinnich's 
guillemot* in the Atlantic, Pallas's murre in the Pacific). Areas of over- 
lap shaded. 

on Bear Island (and often to be seen at sea in the Rockall area), and 
the situation among the fulmars is therefore one not of dimorphism 
but of polymorphism, as it is among the skuas. 

♦The Briinnich's guillemot, U. lomvia, does nest in Newfoundland on Funk Island 
on a little island on the east side of the Avalon Peninsula just south of St. John's 
(Green Island in Witless Bay) and on Cape St. Mary, S. W. Avalon. These colonies 
were discoved by Leslie Tuck; the last in company with J. F. in April 1953, too late 
to alter the map. 



^8 SEA-BIRDS 

Southern, who has carefully studied the problem of the differential 
distribution of the bridled guillemot, thinks that its 'bridle' is probably 
controlled by a single Mendelian factor, which appears to control also 
a slight difference in the skull structure and the shape of the tail- 
feathers. He organised counts of the percentage of bridled guillemots 
throughout Britain in the years round 1939 and again in those round 
1949; and he has also collected as much evidence as he could from the 
rest of the guillemot's range. Two main conclusions are apparent: 
first, the percentage of bridled birds increases from SSE to NNW 
(with a reversal in Iceland) ; and secondly the percentage is not always 
constant at any one place — there are signs of trends towards increase 
or decrease, and of shifts, or drifts, of the balance. Possibly the 
possession of a bridle gives a guillemot an advantage over other guille- 
mots in some environments, and a disadvantage in others, though we 
do not know why: the alternative is that possession of the bridle is 
the result of an advantageous mutation that is spreading through the 
population; which is unlikely to be the case on the evidence, though 
Southern has been careful to show that the possibility still exists. 
There is no indication that bridled guillemots prefer to mate with 
each other rather than with unbridled guillemots; mating in a 
mixed colony appears to be completely, or almost completely, at 
random. 

Southern shows that the percentage of bridled birds marches 
fairly closely with humidity and cloudiness; but, as he points out, 
many other factors may be involved. The changes between r.1939 
and ^.1949 may be linked with the climatic amelioration, but "might 
very well be due to random fluctuation." The actual percentages as 
recorded in the paper of Southern and Reeve (1941) and Southern 
(1951), and in a few notes published by other observers, are shown on 
the maps (Figs. 9a, 9b). The results of Southern's enquiry of 1949 
have shown that out of the very many colonies studied in Britain 
at only five has a significant'^ change been recorded in ten years, four 
of which show decreases of the percentage of bridled birds and one 
an increase. One of the decreases is at St. Kilda, where the expedition 
of 1939 found 16.5 per cent, of the guillemots bridled and that of 
1948 only 10.3 per cent, (one of us took part in both counts). Other 
decreases in Britain have been significant, as at the Isle of May, 5.3 to 

*This means, here, not only mathematically significant by the ordinary X^ test 
(not likely to occur by chance more than once in twenty times), but also based on 
counts by observers whose reliability has been checked against other observers. 



EVOLUTION 49 

3.2 in ten years; and at Unst in Shetland — 23.8 to 16.9 per cent, in the 
same period. There has also been a significant decrease — of about 
one-third — in Iceland; thus at Grlmsey in the north, from 8.7 in 
1939 to 6.9 per cent, in 1949; at Hafnaberg, in south-west Iceland, 
from 29 per cent, in 1939 to 18.1 per cent, in 1949; in the Westmann 
Islands a parallel decline from 75 per cent, in 1935 (Lockley, 1936) 
to 50 per cent, in 1949. 

Increases noted in the 1939- 1949 enquiries were several, but only 
one, at Foula in Shetland, was significant and by checked observers 
(from 24 per cent, in 1938 to 29.4 per cent, in 1948-49). Increases 
on the margin of significance were recorded from St. Bee's Head in 
Cumberland, Marwick Head in Orkney, and the Fair Isle. Apart 
from these small increases in the last decade, there was a significant 
increase of the percentage on Noss in Shetland from 15.5 in 1890 
to 26.5 in 1938, which seems great enough to embrace a possible slight 
observer-error. 

Unfortunately, too few of the early bridled guillemot counts are 
reliable, though some from Berneray and Mingulay ('Barra Head') 
in the Outer Hebrides may be so. This had 20.2 per cent, in 1871; 
12 in 1939; 9.8 in 1949; 12.6 in 1950. The decrease between 1871 
and 1939 is significant, though the other apparent changes are not so. 
Elsewhere we have followed Southern in discarding such vague 
records as 'about one in every nine or ten.' 

Nothing is yet known about the percentage of bridled guillemots 
along the coast ofNorway, except that it has remained slightly over 
50 per cent., at Bear Island from 1932 to 1948. At the Karlov Islands 
off the Murmansk coast the percentage was 42 in 1938. It seems 
likely, from the rather scanty figures from Novaya Zemlya, which 
Southern slightly misdates and misplaces, that the percentage may 
be about the same on islets in Pukhovy and Bezymiannaya Bays oflf 
that island (36.4 and 50). 

These changes are curious and it is clear that much remains to 
be solved about this interesting problem in distribution and evolution. 
Nor is much known about the distribution of the bridled form in the 
New World, save the following: H. F. Lewis found 128 bridled out of 
a sample of 724 (17.7 per cent.) in the colonies along Quebec Labrador 
in 1929. One of us found 51 bridled out of a sample of 295 (17.3 per 
cent.) at Cape St. Mary, on the south-west corner of the Avalon 
Peninsula of Newfoundland, in 1953. In June, 1940 at Funk Island 
and other parts of the east coast of Newfoundland within forty miles 

E 



60-- 



Zocka/l 



IV 12' If 10' 9° 6' 7* 6* 5° 4' 3* 2* 1' O' 

■_L I 1 1 T I I : I \ I I I I 



r^ 



1' 2' 



lOOKM 12 



MI LES 



11 



km: 



4 16-9 (-) 5 



29-4 (+)• 71^ 23-5 






t5-3W: 



WLONG. 9 



-12 




1 E LONG 



Fig ga 

The principal breeding-colonies of the common guillemot in Britain. The percentages 
of bridled forms in the breeding-populations, as determined chiefly by H. N. Southern 
and his colleagues, are shown. Minus and plus signs in brackets indicate changes in 
the decade c. 1939-t. 1949 which are significant, or on the borderline of significance. 
Crossed circles mark sites of former colonies. 



EVOLUTION 




Fig. gb 

The distribution of bridled guillemots in the East Atlantic breeding-populations: 

O: no bridled birds observed. A: under i per cent bridled. B: under 2 per cent bridled. C: under 

5 per cent bridled. D: under 10 per cent bridled. E: under 20 per cent bridled. F: under §0 per 

cent bridled. G: over ^o per cent bridled. 



52 SEA-BIRDS 

of it W. Templeman (1945) collected twelve common guillemots 
(? at random) of which six (50 per cent.) were bridled. When Horring 
and Salomonsen (1941) compiled a list of all the common guillemots 
that had been then collected on the west coast of Greenland they 
recorded six out of thirty-two (18.7 per cent.) as bridled, but knew of 
no breeding-colony. Soon afterwards Salomonsen (1944) became aware 
of the colony in the Sukkertoppen district; but no count has apparently 
yet been made there. 

All the four skuas appear to vary in plumage; the bonxie (great 
skua) particularly in the amount of rufous colour, especially among 
some of its southern forms; the three smaller skuas have a 'normal' 
pale phase of plumage with light breast and underparts, and yellowish 
or buff on the sides of their necks ; and a 'dark' phase which is almost 
uniformly, or uniformly, dusky; and intermediates. The dark phase 
of the long-tailed skua is so rare that it has hardly ever been seen. 
Among the population of pomarine skuas, wherever they may breed, 
from five to twenty per cent, are dark; the distribution of dark birds 
is even, in the sense that there is no detectable gradient. Southern's 
detailed analysis (1944) shows that no geographical area contains 
significantly more dark pomarine skuas than any other. Among the 
arctic skuas (Southern, 1943), however, the situation is quite different. 
In the southern parts of this bird's breeding-range about three- 
quarters of the birds are dark; in the middle parts about half, in 
the Low Arctic less than half, and in the High Arctic a quarter or less. 
In north-east Greenland, indeed, the dark form is unknown. There are 
a few, rare, birds intermediate in colour between the pale and dark 
forms. This looks like a quivering balance between two 'stable' types. 
The proportion of the colour-forms in the British colonies is (Southern 
points out) subject to rather special considerations, since the colonies 
are generally small and scattered, and thus liable to random fluctu- 
ations — in fact between the limits of 50 and 86 per cent. dark. The 
mean probably lies at about 75 per cent. 

Southern has attempted to correlate the distribution of the dark 
arctic skuas (Fig. 10) with temperature, relative humidity and various 
ecological factors. His material carries darkness with humidity over 
a considerable part of the bird's total range; but the correlation breaks 
down in Norwegian Lapland — also, good meteorological figures are 
not available for all the arctic regions. 

We found the same difficulty in correlating the distribution of the 
colour phases of the fulmar, Fulmarus glacialis, with climate and other 




*#*^- 



Air .Ministry, Crown Copyright Reservid 



Plate I. RocKALL lies over 200 miles west of the Outer Hebrides: a granitic rock 70 feet 
high, it is an Atlantic resting-post for sea-birds rather than a breeding-place. Heavy- 
seas wash over the top in bad weather. The shallow seas around are a rich feeding- 
ground for tube-noses, auks and Gannets 



'■-^'•"^V 




Plate Ila. Eldey, Iceland : one of the last refuges of the Great Auk. The flat top is occupied 
by c. 9,000 pairs of nesting Gannets [James Fisher) 

b. Elegug Stack, Pembrokeshire. Occupied by Common Guillemots on top, 
and Razorbills in crevices at sides, with Kittiwakes on the sheer walls {R. M- Lodiey) 

' f . 









-V^'" 



Vl^l 



m 




4: J' 






^r^ 



EVOLUTION 



53 




Fig. 10 

Distribution of colour-phases of the arctic skua, Stercorarius parasiticus, from 
H. N. Southern (1943), showing isoHnes for percentage of the pale phase 

in the breeding population. 

environmental factors. In the Atlantic (though not the Pacific) part of 
the fulmar's range the situation is in many ways the opposite of that 
among the arctic skuas; where the surface of the sea is above freezing 
(i.e. in the Low Arctic and rest of the range) the fulmars are nearly all 
light. The gradient runs from o per cent, dark in Britain to a hundred 



54 



SEA-BIRDS 




Fig. 1 1 
Breeding distribution of the fulmar, showing the approximate preponder- 
ance of dark birds in the populations, indicated by the dark parts of the 

circles {from Fisher, ig52) 



per cent, (probably) in the High Arctic of Spitsbergen and Franz Josef 
Land; in West Greenland (Low Arctic) the fulmars are very nearly 
all light. Finn Salomonsen suggested to Fisher (1952) a correlation 
between this distribution (Fig. 11, above) and surface water-tempera- 
ture. Dark fulmars are only found in the areas where the water is 
nearly freezing, or freezing, in July, in which month the adults collect 
food for the chick fulmar. It is interesting to note that approximately 



EVOLUTION 55 

the fifty-fifty situation in the distribution of colour-phases of the fulmar 
(as also of the bridling in the guillemot) is found at Bear Island, whose 
position is between Low and High Arctic. However, the Pacific fulmar 
appears to reverse the situation found in the Atlantic; the dark 
fulmars are found in the warmer parts of the Pacific fulmar's range, 
and the light fulmars progressively towards the colder parts, though 
nowhere does this race of the fulmar breed in truly High Arctic waters. 
The existence of these polymorphic forms of some birds constitutes 
a problem of the greatest interest, which travellers and amateur 
naturalists might well help to solve by collecting simple counts of 
the relative proportions of easily recognisable forms. 



CHAPTER 3 

SEA-BIRD NUMBERS AND MAN 



EVERY BIRD has a history, which is a tale of adventure and fluctuating 
fortunes, of success, or of failure; for every bird, like every other 
animal, suffers change. In any study of the life of birds, and the place 
of birds in nature, an understanding of their numbers is fundamental. 
Since most sea-birds are social animals, and nest in colonies in 
wild and beautiful places, their numbers can often be studied very 
closely, and with a great deal of enjoyment. So enthusiastic is the 
average amateur bird-watcher about visiting sea-bird stations, and 
'collecting' islands, that it is safe to say that every important sea- 
bird colony on both coasts of the United States (not Alaska), and on 
those of the Faeroes, Britain, France, Belgium, Holland, Denmark, 
Germany, Finland, and Sweden is known to somebody who can dis- 
tinguish its birds from each other; and most of those in Norway, Spain, 
Portugal, Iceland and St. Lawrence-Canada are known. The sea-bird 
stations of Greenland, thanks to a tradition of accurate observ^ers 
from Giesecke to Bertelsen and Salomonsen, are better known than 
those of the Canadian Arctic, Newfoundland, the U.S.S.R., China, 
and perhaps even Japan. Those of the Antarctic and Subantarctic, 
and South America, are perhaps better known than those of the tropical 
Pacific. Probably a very adequate list of the sea-bird stations of the 
United States (excluding Alaska) or of north-west Europe could be 
compiled by some bibliophilic ornithologist with access to all the local 
as well as national bird and natural history journals of those countries. 
Such lists would be useful documents ; they would have to be carefully 
dated, because of what history tells us of the fortunes of animals, and 
of change. Fisher has recently compiled a dated list of all the fulmar 
colonies of the world, and we have both, at different times, compiled 
lists of the world's gannetries. It is surprising how certain it is possible 
to be of being complete, within reasonable limits. Thus after the publi- 
cation of his Report on the igj8 survey of black-headed gull colonies 



SEA-BIRD NUMBERS AND MAN 57 

P.A.D. Hollom (1940) had no colony known (or not known) to be 
occupied in 1938 to add or subtract from his Hst of 342 such colonies. 
When Fisher and Vevers (1943-44) organised a census of the North 
Atlantic gannet in 1939, only two small colonies of the twenty-three 
which then existed were overlooked in that year. When Fisher and 
Waterston (1941) reported on the fulmar colonies known to them in 
Britain in 1939 they believed that there were 208 separate stations 
at which the fulmars were breeding. Ten years later, after carrying 
on research and correspondence with the same intensity to discover 
the situation in 1944 and 1949 (during which 'back information' 
was also collected), Fisher discovered that he had overlooked only 
nineteen, all small (and some in very remote parts), and unimportant 
as far as the fulmar's population, or the actual extent of its range, were 
concerned. 

A census of the sea-birds of the North Atlantic is no longer a wild 
dream. A start has been made with certain obvious species, with 
limited distribution or small populations. The organisational prob- 
lems are not insuperable; we have an ever-increasing body of highly 
competent bird-watchers available for, and keen on, the counting 
of nests: for a sea-bird census depends on the assessment of the number 
of occupied nests. Such a census has already been performed for 
several species on the coasts of Germany (Schulz, 1947), and, judging 
from the descriptions of the distribution of sea-birds in Sweden (Lunde- 
vall, unpublished), Denmark (Jespersen, 1946, and Loppenthin, 
1946), the Netherlands (van Ijzendoorn, 1950) and Belgium (Ver- 
heyen, 1951), it need not be long before a census of the southern North 
Sea and Baltic could be complete. In Britain good surveys, if not 
censuses, exist for the sea-bird colonies of most counties in England, 
and there are records published in the present century concerning 
almost every bird-cliff in mainland Britain (though not every species 
on the cliff) and many in the Hebrides, Northern Isles and Ireland. 
Complete censuses, or careful estimates, have been made of many 
species of sea-birds in various countries with a North Atlantic-Arctic 
seaboard; of which a selection is: 

Some Censuses 

of apparently occupied nests (i.e. an approximation to the 
apparent total hv tiding pairs) of North Atlantic sea-birds in some 
parts of their range (in a few cases, world census) . Censuses of 



58 SEA-BIRDS 

single colonies are not included unless these are of great import- 
ance. 

Fulmar, ^.100,000 in Britain, including St. Kilda, in 1949 (and five-yearly 
estimates since eighteen-seventies ; Fisher, 1952): c.350 in Norway in 1947 
(P. Valeur, 1947): c. 200,000 in West Greenland (F. Salomonsen, 1950): 
c.200,000 on Bear I. in 1932 (Bertram and Lack, 1933): c. 100,000 + at 
Cape Searle, Baffin I. in 1950 (V. G Wynne-Edwards, 1952). 

North Atlantic (Corys) shearwater, c. 2 0,000 on the Salvages, pertaining to 
Madeira, in 1939 (R. M. Lockley, 1952). 

Great {Tristan great) shearwater, world population between 2 and 2^ million, 
all on Tristan da Gunha in 1949-50 (M. K. Rowan, 1952). 

Cahow, world population all on Bermuda where 13 or 14 nests found and 
1 95 1 population "perhaps of the order of 100 adult birds, there may be 
fewer, but there are not likely to be more." (Murphy and Mowbray, 1951). 

Leaches petrel, c.2,000 in Britain; this estimate contains a guess of 1,000 
nests on St. Kilda in 1931 which is unreliable since not all the St. Kildan 
islands on which the species nests were visited (Atkinson and Ainslie, 
1940): C.I 3,000 in Newfoundland in 1942-45 (Peters and Burleigh, 195 1). 

American white pelican, world population c 15,000 in 1932 (B. H. Thompson, 
1932). 

North Atlantic gannet, world population <:.83,ooo in 1939, of which (;. 70,000 
in Iceland-Faeroes-Britain; in 1949 c.82,000 in Iceland-Faeroes-Britain 
(Fisher and Vevers, 1943-44, 1951). See p. 83. 

Double-crested cormorant, Population entire n.e. subspecies P. a. auritus, 
c.20,000 in 'twenties (H. F. Lewis, 1929); re-established on eastern sea- 
board U.S. t.1925 (E. H. Forbush, 1925, H. L. Mendall, 1936); ^900 
in 1 93 1 (Norton and Allen, 1931), over 10,000 in 1944 (A. O. Gross, 1944). 

European cormorant, in Holland c. 1,200 in 1926, c.2,600 in 1934, <;.4,ooo in 
i937» 4>622 (peak) in 1940, 4,359 in 1941 (van Ijzendoorn, 1950); in 
Belgium 30 in 1950 (R. Verheyen, 1951); in North America 1,086 in 
1940 (H. F. Lewis, 1941). 

Great skua, }ust over 100 in the Faeroes in 1942, c.200 in 1946 (K. Williamson, 
1945b, 1948, L. Ferdinand, 1947); c. 1,000 in Great Britain (all Shetland 
and Orkney) around 1 946 (R. Perry, 1 948, Royal Society for the Protection 
of Birds watchers and other sources). 

Ring-billed gull, c. 1,750 in Gulf of St. Lawrence in 1940 (H. F. Lewis, 
1941b.). 

Common gull, ^7.500,000 in Denmark in 1939 (P. G6roudet, 1946); 20,221 



SEA-BIRD NUMBERS AND MAN 59 

in Germany in 1939 (Schulz, 1947); ^^.250 in Holland in 1949 (van Ijzen- 
doorn, 1950); a few occasionally on the Belgian border (Verheyen, 1951); 
C.30 in England in 1941. 

Herring-gull, c.27,500 in Holland in 1938 (van Ijzendoorn, 1950); 28,569 
on North Sea coast of Germany in 1939 (Schulz, 1947); under 9,000 in 
Maine in c.1900, c. 16,500 in 1921, f:.25,ooo in 1931 (Norton in Palmer, 

1949)- 

Lesser blackback, i in Germany 1927-28, c.6 in 1938-47 (Schulz, 1947); 
colonised Holland since 1926, not more than 50 (van Ijzendoorn). 

Great blackback, c. 1,1 00 in England and Wales in 1930 (Harrisson and 
Hurrell, 1933); c.20 in Denmark in 1941 (F. Salomonsen, 1943); 16 on 
Bear Island in 1948 (Duffey and Sergeant, 1950); 3 in United States in 
1928, at least 1,250 in 1944 (A. O. Gross, 1945). 

Laughing gull, c.25 in Maine in 1860-70, i, 2, 3 or 4 from c. 1884 to ^.1918, 
C.150 in 1931, 1936, C.250 in 1937-38, c^oo in 1940, c.50 in 1941, none 
since. (Palmer, 1949); in Western U.S. 2 in 1928 (Miller and van 
Rossem, 1929). 

Black-headed gull, 35,000 in England and Wales in 1938 (P. A. D. Hollom, 

1940, S. Marchant, 1952). 

Little gull, 15 in Holland in 1942, 18 in 1943, 13 in 1944, i or 2 in 1945, 
<:.8 in 1949 (van Ijzendoorn). 

Kittiwake, 6,000 to 8,000 in England in late 1940's (J. Fisher, from literature 
and notes); 11 in Denmark in 1941, 15 in 1942, 124 in 1946 (Salomonsen, 

1941, Loppenthin, 1948); 1-3 in Germany in 1938-39 (R. Drost, 1939); 
24,400 in Newfoundland in 1941-45 (Peters and Burleigh); probably 
t.10,000 in Gulf of St. Lawrence in 1940 (H. F. Lewis, 1941b and others). 

Black tern, 8 in Britain in 1941, 5 in 1942 (R. Cooke, 1946); none in other 
recent years. 

Whiskered tern, 8 in Holland in 1938, 9 in 1945 (invasions; van Ijzendoorn). 

White-winged black tern, i in Belgium in 1937 (R. Verheyen, 1951). 

Gull-billed tern, i in Holland in 1931, i in 1944, 2 in 1945, 3 in 1949 (van 
Ijzendoorn) . 

Caspian tern, 300 in Germany in 1819, 25 in 1874, none since 1918; 7 in 
California in 1922, 296 in 1930, 378 in 1943 (A. H. Miller, 1943); c.200 in 
Gulf of St. Lawrence in 1884 (M. A. Frazar, 1887), 30-55 between 1925 
and 1940 (H. F. Lewis, 1941b.), 45 in 1945 (O. H. Hewitt, 1950). 

Common tern, c. 4,450 in Maine in 1931-36 (Palmer, 1949); c. 15,000 in 
Cape Cod region of Massachusetts in 1930-44 (O. L. Austin, 1946) ; 
15,000-16,000 in Germany in 1939 (Schulz) ; c. 19,000 in 'de Beer' sanctuary, 
Hook of Holland, in 1939 (van Ijzendoorn); doubtful whether in any year 



60 SEA-BIRDS 

in the present century more than 7000 in England and Wales, and likely 
that over half of these have been in Norfolk (J. Fisher from literature and 
notes) . 

Arctic tern, ^.5,970 in Maine in 1931-36 (Palmer); c.4.,joo in Germany 
in 1939 (Schulz) ; probably under 200 in Holland (van Ijzendoorn) ; doubt- 
ful whether in any year more than 3,000 in England and Wales, and likely 
that over half of these have been in the Fame Islands (J.F.). 

Roseate tern, c.276 in Maine in 1931-36 (Palmer); i or 2 in Germany in 
most years since 1904 (Schulz); 2 in the south of France in 1951 (R. M. 
Lockley); over 1,000 in the British Isles in recent years, about a third of 
which are in Anglesey and about half of which are in Ireland (J.F.) 

Sooty tern, in Pacific c. 166,950 on Laysan Island (Dill & Bryan, 19 12); 
in Indian Ocean over 25,000 in 1937 on Goelette, <:.65,ooo on Bird Island 
(Seychelles), c.5 million in 1931 and at least j million in 1937 on Desnoeufs 
(D. Vesey-Fitzgerald, 1941); in U.S.A. (breeds Dry Tortugas only) c.7000 
in 1903, 9,000 in 1907, 10,000 in 1908, 9,000 in 191 7, 15,000 in 1935, 
20,000 in 1936, 50,000 in 1937, 32,029 in 1938, 35,000 in 1939, c.50,000 
in 1940, over 50,000 in 1941, 32,500 in 1942, 54,500 in 1945, 48,600 in 
1946, 32,135 in 1947 (P. Bartsch, 191 9; A. Sprunt, 1948). 

Sandwich tern, c.40,000 in Holland in 1940 (van Ijzendoorn, 1950); this 
perhaps four- fifths of whole population of north-west Europe; other 
occupied countries, all with very fluctuating numbers, Sweden (200-300 
nests in early 'forties), Germany (3,957 in 1940), Denmark (unknown 
number), the British Isles (fluctuating between two and five thousand nests, 
and about 3,500 in early 'forties, J. F. from literature and notes), and 
Danzig, Brittany and Portugal (a few each). 

Noddy, in U.S.A. 200 in 1903, 2,000 in 1907, 700 in 1908, 2,000 in 191 7; 
1,500 in 1935, 2,000 in 1936, 1,000 in 1937, 206 in 1938, 125 in 1939, 90 
in 1940, 500 in 1941, 225 in 1942, 375 in 1945, 275 in 1946, 125 in 
1947 (as sooty tern). 

Little auk, in Iceland, now breeds Grimsey only, where c.50 in 1820, 
150-200 in 1903, ^.20 birds in 1934, at least 19 birds in 1949 (see p. 123.) 

Razorbill, 12 in Germany in 1939 (Schulz), all on Heligoland; 318 in Den- 
mark in 1939 (Salomonsen, 1943), all on Graesholm, where 60 pairs in 
1944 (K. Paludan, 1947). Peters and Burleigh (1951) suggest that there 
may not be more than 450 in Newfoundland. 

Common guillemot, c. 25,000 pairs in Sweden in early nineteen-forties (F. 
Salomonsen, 1944), nearly all on Stora Karlso, where only 10 in 1880, 
C.I, 250 in 1918; in Denmark established Graesholm in 1928, c.6o in 1936, 
100 in 1938, 122 in 1939, 127 in 1940, 208 in 1941, 158 in 1942 
(Salomonsen, 1943, 1943b); c.200 in c.1946 (P. Jespersen, 1946); in 
Germany c.2,000 all on Heligoland (Schulz and ourselves). Peters and 
Burleigh (1951) suggest that there may not have been many more than 
25,650 in 1941-45 in the whole of Newfoundland, but it seems clear that 



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s 


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— ■ „ j l jj- i^'l'*' 



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****«► 



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Roger T. Peterson 

Plate III. A sandy shore habitat : Sooty Terns at Bush Key, Dry Tortugas, Florida, U.S.A. 




Roger T. Peterson 

Plate IV. The Double-crested Cormorant often nests in trees with egrets. Redfoot Lake,, 
Tennessee, U.S.A. (about i,ooo birds in colony) 



SEA-BIRD NUMBERS AND MAN 6l 

the total west Atlantic common guillemot population is at least 40,000, 
of which there are about 7,700 in Quebec Labrador (R. A.Johnson, 1940), 
c. 10,000 on Anticosti Island (H. F. Lewis, 1941c.), and perhaps 500 on 
Bonaventure Island in Quebec and 700 on the Bird Rocks in the 
Magdalen Islands (A. C. Bent, 19 19). 

Brunnich's guillemot, c. 2 million in Greenland (Salomonsen, 1951). 

Black guillemot, c.250 in Maine in 1948 (Palmer); 3 in England in 1940 
(Cumberland; Blezard and others, 1943). 

Atlantic puffin, world population 1952, not less than 7,612,500, of which 
2,500,000 each Iceland, Faeroes; 2,000,000 Brit. Is. (J.F. thinks this an 
under-estimate) ; 62,500 France, Channel Is. (R.M.L., 1953). 

Though this list includes some very small numbers of sea-birds 
breeding in some countries and lands desukorily, or at the very edge 
of their range, there have been some big censuses; and of five North 
Atlantic sea-birds, Tristan great shearwater, cahow, American white 
peUcan, gannet and puffin, we have estimates of the world population. 

We must again remind readers that the figures do not refer to 
birds (unless this is particularly pointed out) ; but to occupied nests 
or breeding 'pairs.' 

Not many of the censuses made so far are of the species with 
very large populations. Indeed, if we were to judge solely from com- 
pleted censuses, we might come to the conclusion that the populations 
of sea-birds were not high. In fact, they are often extremely high. 
"The Fulmar Petrel lays but one tgg,'' wrote Darwin in The Origin 
of Species, "yet it is believed to be the most numerous bird in the world." 
We now know (Fisher, 1952) that, while there may be over two 
million, there are under ten million fulmars in the world, and that, 
far from being the most numerous bird, the fulmar is less numerous 
than many sea-birds, and even some land-birds. One of us has already 
suggested (Fisher, 1940) that "the most abundant bird in the world 
is certainly a sea-bird, and probably \Vilson's petrel," and nothing 
discovered in the last ten years has encouraged him to change that 
view. Nevertheless, many species of sea-birds are astonishingly abund- 
ant, and quite a number of North Atlantic species, if not vastly 
numerous in the Atlantic proper, certainly darken the sky round their 
arctic breeding-haunts just as Wilson's petrels darken some antarctic 
skies. The miles of cliffs round Bear Island (especially at its south end) 
harbour millions (an unknown number of millions) of Brlinnich's 
and common guillemots. Some of the buttresses rise fourteen hundred 



62 SEA-BIRDS 

feet sheer from the sea, and, as Bertram and Lack say, "have been 
described with justice as the finest bird-cHffs in the Northern Hemi- 
sphere." However, those of St. Kilda are (in one place) also fourteen 
hundred feet high, and are more varied, with a better-known history. 
Those who have seen both may think St. Kilda finer, though Bear 
Island has more birds and is more magnificently sinister. It certainly 
has a higher sea-bird population than any comparable place in the 
North Atlantic- Arctic ; though it seems to have competitors in the 
Pribilov, Aleutian and Kurile Islands and other parts of the North 
Pacific. But there are many great bird-stations besides Bear Island 
and St. Kilda, where the observer may behold a community of a 
million birds or more. On the basalt cliffs of the Faeroes, particularly 
north-west Streymoy, he may find this number. Perhaps nowhere 
in Iceland is there a cliff-site with a million birds, but there are many 
rocks with many thousands, from the Westmann Isles in the south 
to Grimsey in the north; from Latrabjarg in the west to SkruQur 
and Papey in the east. Jan Mayen has at least a million sea-birds; 
and there may well be millions at more than several places in Spits- 
bergen; perhaps on the hills of Horn Sound, Cloven Cliff off the 
north-west, Magdalena Bay and Brandy Bay in North-east Land; 
almost certainly on the Vogel Hoek of Prince Charles Foreland, the 
great auk hill of Advent Bay, and the dolerite Alkrange of Hinlopen 
Strait. A pioneer ecologist and student of animal numbers (Elton in 
Longstaff, 1924) wrote of the Alkrange: — 

*'It is impossible to describe the multitudes of the Guillemots on 
the bird cliffs. The place was teeming with them: literally hundreds 
of thousands. The cliffs are made of columnar dolerite which weathers 
into pinnacles and which rise several hundred feet sheer out of the 
sea. On the numerous narrow ledges the birds were so crowded that 
there was room for no more. The rows of black and white birds rising 
in tiers up to near the top, and the ghostly noise of the combined 
twitter made by them, made it seem as if one was in a vast opera house, 
packed with crowds of people in white shirt-fronts and black tails, 
all whispering comments on each other and rustling their pro- 
grammes." 

It seems clear that either the little auk or Briinnich's guillemot is 
the most abundant bird of the north. It is hard to decide which; 
the little auk colonies are perhaps fewer, and certainly less obvious 
as dense loomeries, because the birds nest in crevices and not on flat 
open ledges. But the dark cloud of circling, twittering dovekies 



SEA-BIRD NUMBERS AND MAN 63 

betrays their density, and we believe with Salomonsen that their 
actual numbers are greater. Nevertheless, some Briinnich's guillemot 
loomeries are vast, and those at Bear Island, Jan Mayen and Spits- 
bergen are not the only ones that are stupendous. The largest loomery 
in the U.S.S.R. is probably that at Bezymiannaya Bay in Novaya 
Zemlya, where S. K. Krasovskii (1937) has estimated that about 
1,600,000 Briinnich's guillemots (birds, not pairs) nest. But Salomon- 
sen (1944) has estimated that in 1936 over two million Briinnich's 
guillemots (birds) bred at the rock Agparssuit (Cape Shackleton), 
north of Upernavik in West Greenland. This was about half the 
population of this species in Greenland. There are many other huge 
bird rocks in Davis Strait and Baffin's Bay; in West Greenland several 
on Disko Island, in Umanaq Fjord (notably Sagdleq, which may 
have a million Briinnich's) and in the Upernavik district (notably 
Qaerssorsuaq, or Sanderson's Hope, where the guillemot cliff is at 
least three miles long and over three thousand feet high and has two 
hundred thousand Briinnich's), and several in the Thule district in 
the far north-west, notably Saunders and Hakluyt Islands, and Cape 
York, which contains what is probably the largest little aukery in the 
world;* nobody has been able to guess how many millions nest there. 
Other huge bird-colonies in the western Arctic are to be found in 
Ellesmere Island, North Devon Island, Bylot Island and Baffin Island. 
Indeed, throughout the Arctic, where the naked rock escapes from the 
clutch of ice, and precipices rear to the sky from shores, the kittiwakes 
and dovekies, the puffins and guillemots, the fulmars, the glaucous 
gulls and pale herring-gulls, make their nests, and operate from them 
to the feeding grounds, to the leads in the ice, the convergences of tide 
and current, the upwelling zones at glacier faces and by the side of 
big icebergs. And below the cliff-ledges is the tell-tale of the bird 
city, rich plants, sudden patches of green in the arctic drab, green 
swards indeed, bright yellow-green grass ; the round leaves of scurvy- 
grass, lush, six times as high as in the barren places, which means six 
inches high. On the slopes of scree and talus and broken rocks below 
is a special mat of little flowering plants, benefiting from the bird- 
dung leached and washed down from above; perhaps not the purple 
opposite-leaved saxifrage, which shuns this community (it is too rich 
for it), but alpine foxtail, the arctic poppy, the arctic buttercups, and 

♦Rivalled by those of Scoresby Sound and the Liverpool Coast in East Greenland, 
whose little auk population (A. Pedersen, 1930) has been estimated at about five 
million birds. 



64 SEA-BIRDS 

the polar creeping willow; and tufted, drooping, alpine brook saxi- 
frages; and the alternate-leaved golden saxifrage; and alpine mouse- 
ear chickweed, various arctic whitlow-grasses, poas and a woodrush, 
and IVahlbergella; and sometimes carpets of Jacob's ladder. There 
are many mosses, too, with bright colours; and all over these arctic 
cliffs — not only below the bird ledges — grow lichens. One of them 
is the beautiful orange Caloplaca elegans; it grows all over the bird 
rocks of Spitsbergen, shines yellow orange among the dark rock and 
green grass-ledges of the fulmar-haunted bastions of Disko in West 
Greenland, and colours from top to bottom the mighty buttresses of 
Cape Searle in eastern Baffin Island, the site of what may be the world's 
largest fulmar colony. Grey fulmars sit on green ledges above orange 
rocks. 

In Britain, St. Kilda is the greatest sea-bird station. Upon its 
thousand-foot precipices nests one of the densest communities of 
vertebrate animals in the North Atlantic — probably the densest 
south of the Arctic Circle. The gannets of Boreray and its stacks have 
about seventeen thousand nests — one-sixth of the world population 
of this species. A quarter of Britain's fulmars (up to forty thousand 
pairs) nest on St. Kilda. Undoubtedly more than a million puffins' 
eggs are laid on St. Kilda in a normal year; the question is, how many 
million? There are seven separate puffin-slopes on St. Kilda each of 
which is larger than the largest puffin colony anywhere else in the 
British Isles, even the largest puffinry in the mossy talus-slopes of the 
Shiant Isles, where blocks of columnar basalt lie below the cliffs 
like the forgotten bricks of a child. The puffin is certainly one of the 
most numerous birds in the North Atlantic. In his monograph on the 
puffin (1953) Lockley estimates a minimum world population of 
15,000,000 adults. 

•t* *J* T* 

From the study of the ecology of animals we are learning that their 
numbers are controlled primarily by the amount of food they can 
get, and only secondarily by their parasites and predators; and 
parasites are probably more important than predators. But there 
are exceptions to this; and the chief one is when the predator is man 
(another is when new predators are introduced through his agency). 
Except in a few places such as most of Greenland, Jan Alayen, Spits- 
bergen, Franz Josef Land and a few other arctic islands, man is, 
or has been, the most important predator of sea-birds. He has been 



SEA-BIRD NUMBERS AND MAN 



65 





Fig. 12 

Upper Palaeolithic (probably Magdalenian) rock-engraving at El Pendo, 

near Santander, North Spain, showing what are probably great auks 

of which modern sketch on left. 

(After H. Breuil, 1911; G. Clark, 1948) 



one, of a kind, ever since he has been Man — even before; for there 
is ample evidence that during the second of the two advances of 
the ice in the second of the two glaciations of the Great Ice Age, some 
of the latest members of the species Homo neanderthalensis ate great 
auks. This was about twenty thousand years ago; the Neanderthals 
left their auk bones in the cave of St. Brelade in Jersey and in the 
Devil's Tower at Gibraltar. Their successors, the first of Homo sapiens, 
Men of the Aurignacian age (the early part of the Upper Old Stone 
Age, <7. 1 6,000 to C.I 1,000 B.C.), were of two main races, the tall short- 
faced Cro-Magnons, and the shorter Grimaldians, perhaps closely 
related to African bushmen (W. J. Sollas, 1924). Great auk bones 
have been found in Grimaldian deposits in the Grotta Romanelli 
in the heel of Italy* and in another cave whose habitation goes back 
to the end of the Old Stone Age, El Pendo in north Spain, a wall- 
etching (Fig. 12, above) of Magdalenian age (c.8,ooo B.C.) may 
represent a great auk (H. Breuil and others, 191 1; G. Clark> 1948). 

*It is of interest to point out that the modern razorbill, the great auk's nearest 
relation, which had a similar breeding-distribution, penetrates into the Mediterranean 
as far as this in winter. 
D 



66 SEA-BIRDS 

It is probable that between the end of the last glaciation of the Ice 
Age (about 15,000 B.C. in southern Europe, about 10,000 B.C. in 
northern) and the present day, i.e. during the Upper Old Stone, 
Middle Stone, New Stone, and Iron Ages the great auk had quite a 
wide distribution; judging by the number of bones, and the presence 
of the bones of young, in some prehistoric kitchen-middens in Britain 
and western Scandinavia, its breeding-range was possibly wider than 
it was found to be in historical times (Gulf of St. Lawrence, Newfound- 
land, Iceland, Faeroes and Britain). We cannot, however, quite agree 
with Clark (1948), who has collected the information about these 
deposits, that it was certainly wider, for it seems to us likely (see p. 268) 
that the young great auk left its breeding skerry very early, perhaps, 
like the razorbill, without either primary or secondary wing-feathers, 
not much more than a fortnight after hatching; and probably swam 
with its parents many hundreds of miles before 'fledging.' Clark's 
list shows great auk bones in middens of the Middle Stone Age in 
France, Denmark, West Sweden and Norway, of the New Stone Age 
in France, Denmark and Norway, of the Iron Age in west Sweden 
and Norway. Several brochs (small forts) in Orkney and Caithness 
inhabited by the Picts also contained great auk bones; this practically 
brings the great auk to historical times. 

We suspect that the prehistoric exploitation of the great auk was 
largely confined to interception of the birds on passage and in their 
winter quarters;* the final collapse and extinction of the species took 
place only when Man in modern ships reached and attacked its 
main breeding-haunts. 

These, as far as can be discovered, were the certain breeding- 
colonies of the great auk: 

In Britain, St. Kilda and Papa Westray 

In Iceland, Geirfuglasker and Eldey, S.W. of Cape Reykjanes and 

Geirfuglasker in the Westmann Islands 
In the Magdalen Islands (Gulf of St. Lawrence), Bird Rocks 
In Newfoundland, Funk Island (east) 

*One of the reasons for thinking that the prehistoric exploitation was at least 
partly of at-sea birds is that the taking of auks at sea is a technical possibility ; 
Williamson (1948, p. 157) describes a method of snaring them on a floating board 
covered with plaited hair loops, to which the auks are attracted by a dummy or 
decoy bird. This has been, and still is, in use in Iceland and the Faeroes; there is 
no doubt that primitive hunters were capable of devising such engines. 



SEA-BIRD NUMBERS AND MAN 67 

Other stations at which it possibly nested, but about which the evidence 
is not entirely satisfactory, are: 

In Britain, the Calf of Man 

In the Faeroes, Fugloy and Streymoy 

In Iceland, Hvalbakur and Tvlsker 

In Maine, the Georges Islands in Knox County 

In Nova Scotia, an island near Yarmouth (? in Tusket Is.) 

In the Gulf of St. Lawrence, Cape Breton 

In Newfoundland, 'Penguin Island' off Cape La Hune (south) 

and 'Penguin Island' near Cape Freels (east) 
In Greenland, Leif 's and Erik den Rode's Islands, near Angmagssalik. 

There is no doubt that the main population, when history overtook 
the great auk, was around the island of Newfoundland, and particu- 
larly upon Funk Island, where, according to Peters and Burleigh 
( 1 951), it was probably first seen in 1 170 by some early Norse explorers 
of the New World from Greenland. 

When Jacques Cartier visited Funk Island on his first voyage to 
Newfoundland in May 1534 his crews filled two boats with the birds 
in less than half an hour, and every ship salted down five or six barrel- 
fuls. Two years later the voyager Robert Hore came to^one of the Penguin 
Islands or Funk Island, and found it full of auks and their eggs. 
They spread their sails from ship to shore and drove a great number 
of the birds on board upon the sails; and they took many eggs. By 1578 
it was the normal thing for French and British crews in the Gulf of 
St. Lawrence or on the Newfoundland Banks to stock their ships with 
auk-meat, stopping at the Bird Rocks, or Penguin Islands or Funk 
Island, and driving the great auks aboard on planks. Today there is 
nothing but old ships' logs and travellers' diaries to record where the 
western auks once lived in thousands, save on Funk Island, where a 
great many bones have been found. 

It seems clear, from the account of Peters and Burleigh, that the 
great auk became extinct in Newfoundland in about 1800. George 
Cartwright (1792), who lived in Newfoundland Labrador for most 
of the period 1 770-1 786, and who often sailed across the Straits of 
Belle Isle to northern Newfoundland, only logged personal meetings 
with great auks in his diary twice, on 4 August 1771 and 10 June 1774. 
On a visit to Fogo Island harbour on 5 July 1 785 he wrote: 

"A boat came in from Funk Island laden with birds, chiefly penguins. 
Funk Island is a small flat island-rock, about twenty leagues 




V 

to 

J3 



bo 
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CO UJ 

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3 



c 
t4 



SEA-BIRD NUMBERS AND MAN 69 

east of the island of Fogo, in the latitude of 50° north. Innumerable 
flocks of sea-fowl breed upon it every summer, which are of great 
service to the poor inhabitants of Fogo; who make voyages there 
to load with birds and eggs. When the water is smooth, they make 
their shallop fast to the shore, lay their gang-boards from the gun- 
wale of the boat to the rocks, and then drive as many penguins on 
board as she will hold ; for, the wings of those birds being remark- 
ably short, they cannot fly. But it has been customary of late years, 
for several crews of men to live all the summer on that island, 
for the sole purpose of killing birds for the sake of their feathers, 
the destruction which they have made is incredible. If a stop is 
not soon put to that practice, the whole breed will be diminished 
to almost nothing, particularly the penguins: for this is now the 
only island they have left to breed upon; all others lying so near to 
the shores of Newfoundland, they are continually robbed. The 
birds which the people bring from thence, they salt and eat, in 
lieu of salted pork. It is a very extraordinary thing (yet a certain 
fact) that the Red, or Wild Indians, of Newfoundland should 
every year visit that island; for, it is not to be seen from the Fogo 
hills, they have no knowledge of the compass, nor ever had any 
intercourse with any other nation, to be informed of its situation. 
How they came by their information, will most hkely remain a 
secret among themselves." 

Nobody knows when the Norse-Gaels of St. Kilda came first to 
Hirta, their main island, and established Britain's most interesting 
colony of wildfowlers. Certainly by 1549 there was a stable human 
community on St. Kilda, whose life was based to a large extent on 
"wyld foullis" (D. Monro, 1774). In about 1682 the Lord Register, 
Sir George M'Kenzie of Tarbat, gave an account (18 18) of St. Kilda 
to Sir Robert Sibbald. He probably did not visit St. Kilda himself, 
but he says: "There be many sorts of . . . fowls; some of them of strange 
shapes, among which there is one they call the Gare fowl, which is 
bigger than any goose, and hath eggs as big almost as those of the 
Ostrich. Among the other commodities they export out of the island, 
this is none of the meanest. They take the fat of these fowls that frequent 
the island, and stuff' the stomach of this fowl with it, which they 
preserve by hanging it near the chimney, where it is dryed with 
the smoke, and they sell it to their neighbours on the continent, 
as a remedy they use for aches and pains." 



70 SEA-BIRDS 

When Martin Martin (1698), tutor to the son of the islands' 
laird, the MacLeod of MacLeod, arrived at St. Kilda in June 1697 
he wrote a classic and accurate account of its natural history, which 
included this: 

"The Sea-Fowl are, first, Gairfowl^ being the stateliest, as well as 
the largest Sort, and above the Size of a Solan Goose, of a black Colour, 
red about the Eyes, a large white Spot under each, a long broad Bill; 
it stands stately, its whole Body erected, its AVings short, flies not at 
all; lays its Egg upon the bare Rock, which, if taken away, she lays 
no more for that year; she is whole footed, and has the hatching Spot 
upon her Breast, i.e. a bare spot from which the Feathers have fallen 
off with the Heat in hatching; its Egg is twice as big as that of a 
Solan Goose, and is variously spotted. Black, Green, and Dark; it 
comes without Regard to any wind, appears the first of May, and goes 
away about the middle o^ June.^^ 

We quote this in full, as it is really a most remarkable and con- 
vincing description. As we explain elsewhere (p. 268) the interval 
between the first of May and the middle of June is about seven weeks, 
the combined incubation and fledging period of the great auk's 
closest surviving relative, the razorbill. The description also otherwise 
fits the bird perfectly. Martin arrived at St. Kilda on i June 1697 
by the calendar of his day, which would be 1 2 June by our present 
calendar. If great auks had actually been breeding on one of the 
islands (Soay would have been the most likely) in that year it is almost 
certain that he would have been shown them by the inhabitants, and 
made some comment thereon in his careful notes: as it is his passage 
that we have quoted reads very much as if the information in it had 
been taken from natives who themselves had seen the bird nesting and 
remembered it clearly, but not from Martin's own observations. 
From this we conclude that the great auk nested at St. Kilda not in 
1697, but within the memory of some alive in that year, i.e. most 
probably in the second half of the seventeenth century; we can also 
conclude from the account that its eggs were sometimes taken. The 
M'Kenzie information for c.i 682 also suggests breeding in this period. 

The great auk appears to have been seen at St. Kilda occasionally 
after Martin's visit. The notes of A. Buchan, who was minister on St. 
Kilda from 1705 to 1730, respecting the bird derive from Martin; 
but Kenneth MacAulay (1764) who was on the island for a year in 
1 758-59, alludes to irregular July visits (not every year) by the great 
auk; he did not see one himself. "It keeps at a distance from [the 



SEA-BIRD NUMBERS AND MAN 7I 

St. Kildans]," he writes, "they know not where, for a course of years. 
From what land or ocean it makes its uncertain voyages to their isle, 
is perhaps a mystery in nature." After MacAulay's visit the only 
certain records of great auks at St. Kilda are two: one was taken at 
Hirta in the early summer of 1821 and kept alive until August. In 
this month it was being taken to Glasgow by ship; near the entrance 
to the Firth of Clyde it was put overboard, with a line tied to its 
leg for its daily swim, and escaped. Another was found on Stac an 
Armin, the highest rock-stack in the British Isles (though no doubt 
the auk got ashore at the shelving corner), in about 1840, and was 
beaten to death by the St. Kildans L. M'Kinnon and D. MacQueen 
as they thought it was a witch. Obviously it had been a generation 
or more since any St. Kildan had seen a garefowl. 

The existence of the great auk in the Isle of Man is indicated by 
a picture of an adult in breeding plumage standing on a ledge on the 
Calf of Man, drawn by Daniel King, probably in 1652. Williamson 
(1939), who draws attention to this earliest British depiction of the 
bird, comments that there is no parallel indication in contemporary 
Manx literature that the great auk inhabited the Calf. It is quite 
possible that it may have bred, though this of course is not proved ; 
there are suitable low rock-shelves on the Manx coast on which it could 
have hauled ashore. 

In Orkney one pair certainly bred in 181 2. It is not at all certain 
that the great auk had previously been a regular breeder at Papa 
Westray (the place of the 181 2 nest), or anywhere else in Orkney. 
The site in 181 2 was in a recess low down on the Fowls Craig on this 
island. The female was killed with a stone while sitting on her egg. 
In 1813 the male was also killed; it was shot by the native Willy 
Foulis for William Bullock, the collector, having lived on the ledge 
after the death of its mate. The natives called them the King and 
Queen of the Auks (Buckley and Harvie-Brown, 1891). 

So much for the great auk in Britain; the last of all, except for 
St. Kilda's 1840 'witch,' was an odd bird which was found at the en- 
trance to Waterford Harbour in Ireland in 1834, was kept alive for 
four months on potatoes, milk, and trout, and which is now in the 
museum of Trinity College, Dublin. 

The early historians of the Faeroe Islands, Ole Worm (1655), 
who died in 1654, and Lucas Debes (1673), both knew the great auk 
and handled live specimens caught in the islands. J. K. Svabo (1783) 
who was in the islands in 1781 and 1782, records the capture of a 



72 SEA-BIRDS 

female on the island of Fugloy which was found on dissection to 
contain a well-formed egg; and Jorgen Landt (1800, 1810), who wrote 
his MS. not earlier than 1797, mentions great auks as "climbing up the 
low rocks." G. J. Graba (1830), who was in the Faeroes in 1828, met 
old natives who had formerly seen the great auk at Vestmanna on 
Streymoy, and one who told him that he had killed one on an egg at 
this place. J. WoUey (1850) in 1849, interviewed an old man who 
"had seen one fifty years ago, sitting among the Hedlafuglur, * that 
is young Guillemots and other birds upon the low rocks, and old 
men told him it was very rare. This was about the time when Landt 
wrote." Wolley was told that formerly, when many were seen, it was 
considered a sign of a good bird year; which suggests that the auks 
may have been desultory visitors for a long time. Finally H. W. Feilden 
(1872) interviewed an old fowler in 1872, who claimed to have killed 
a great auk on the island of Stora Dimun on i July 1808; the last 
record for the Faeroes. K. Williamson (1948) points out that none 
of these records constitutes proof of breeding, though we agree with 
him that, though scarce, it probably did breed in the Faeroes until 
the eighteenth century. 

The great auks of southern Iceland are well documented, and their 
history has often been related. They certainly bred on two, and perhaps 
bred on four Geirfuglaskers^ or gare-fowl skerries off the coast; from 
east to west these can be identified as Hvalbakur, the most easterly 
point of Iceland, about 26 statute miles east of the island of Papey, 
near Djupivogur; Tvisker off BreiSamerkursandur under the great 
southern ice-cap of Vatnajokull; Geirfuglasker, the southernmost islet 
of the Westmann Islands, and the most southerly point of Iceland; 
and (until it sank beneath the waves in a volcanic disturbance in 
1830) Geirfuglasker, nineteen or twenty miles south-west of Cape 
Reykjanes, the most south-westerly point of Iceland save a rock 
Geirfugladrangur less than a mile further to sea, which still stands 
but was probably never inhabited by great auks. After the volcanic 
disturbance the garefowls went for as long as they were spared to 
the island of Eldey^ almost exactly between Geirfuglasker and Gape 
Reykjanes. 

It would seem from the accounts of Olafsson (1772) and Olavius 
( 1 780) that Hvalbakur, the distant whale-back skerry of east Iceland, 
may have been inhabited by great auks when those historians were in 

*Williamson (1948) gives '^Hellefuglar: sea-birds 'fleyged' [see p. 99] when 
flying at the foot of the diffs." 



SEA-BIRD NUMBERS AND MAN 73 

Iceland (between 1752 and 1777); but when N. Mohr (1786) visited 
nearby Djupivogur in 1781 he evidently found no news of occupation 
in that year. If it was true, as Olafsson thought, that Tvisker (a skerry 
which at present slopes up to a height of about 46 ft.), was a breeding- 
place, its occupation must be put before 1764, the last year he was in 
Iceland; there is no subsequent history here. In the eighteenth 
century the Westmann islet of Geirfuglasker (which rises to 190 ft., 
but, as we have seen, has a low platform on one side and low skerries 
around), had a big colony but, as Friedrich Faber (1822), records, 
the last known breeding-pair and egg were seen there in about 1800. 

The end of the great auk in Iceland, and in the world, took place 
south-west of Gape Reykjanes. It seems probable that the great auks 
nested only on Geirfuglasker and afterwards Eldey, and never on the 
satellite stacks belonging to these rocks — Geirfugladrangur and Eldey- 
ardrangur. It was known that great auks occupied Geirfuglasker, anc^ 
were at least occasionally raided by Man, in the first half of the 
seventeenth century. Though the accounts of the eighteenth century 
(e.g. J. Anderson, 1746; N. Horrebow, 1752) sometimes slightly 
conflict it seems clear that Geirfuglasker was occupied in 1729 and 
that in some years of the first half of that century (if not, perhaps, in 
that particular year) its great auk population was a "great multitude." 
Nevertheless, it could have been exaggerated. Horrebow stated that 
at his time the Geirfuglasker fowlers "filled their boats with the eggs 
of the Garefowl." (All through the early, uncritical literature of fowling 
we find boatloads of eggs — they have even been allegedly taken from 
Rockall, where seldom have more than a couple of dozen guillemots 
been seen in attitudes of incubation.) But a manuscript of ^.1760 
(S. Grieve, 1885, p. 19) states that the "garefowl is there not nearly 
so much as men suppose . . . the space he occupies cannot be reckoned 
at more than a sixteenth part of the skerry . . . and this only at the two 
landing-places; further upwards he does not betake himself, on account 
of his flightlessness." Mohr, who visited Iceland in 1780-81, also 
thought Horrebow's account exaggerated, though he did not go out 
to the skerry himself. 

In the nineteenth century the doom of the auks was sealed by the 
raid of the Salamine, a private pirate-ship which had plundered Tor- 
shavn in the Faeroes on its way north. The crew of this ship was 
ashore on Geirfuglasker on (it is said) 8 August (? a late date) 1808, 
and killed many birds and their young. There may have been another 
raid from the Faeroes in 1809 (H. C. Muller,i862) ; there was certainly 



74 SEA-BIRDS 

a big one in 1813, when, during the war between Britain and Denmark, 
the armed schooner Faeroe landed a party which killed all garefowls 
that came within their reach, and arrived later in Reykjavik with 
twenty-four on board, besides numbers that had been salted down; 
fifty or sixty were taken back to the Faeroes. On i July 1821 Friedrich 
Faber and H. C. Raben visited Geirfuglasker, and Raben actually 
climbed Geirfugladrangur. They saw no garefowls at all: it is possible 
that the auks might have already gone to sea (especially if their eggs 
had already been taken that season). In 1828 at least one adult was 
taken, for a skin for the Copenhagen Museum. This is the last visit 
to Geirfuglasker that we hear of; in early March 1830 a series of 
earthquakes took place in which the skerry sank beneath the sea. The 
great auks moved at once to Eldey, ten miles nearer the coast, and 
attempted to breed there in the same season. 

Eldey is a remarkable block of volcanic tuff with sheer sides and 
a flattish top that is distinguished by being the site of the second 
largest gannetry in the world (p. 83). It is about 250 feet high, at 
its highest point. On the east side of its north end, below the cliff, 
is a broadish ledge which slopes and slants into the sea (PL Ila, p. 53), 
and, as one of us (Fisher) who visited it in 1949 saw for himself, was a 
suitable landing place and, under the sheer cliff, also a suitable 
nesting-place for the garefowls. Eldey is made of a particularly 
resistant type of volcanic tuff; normally such a formation weathers 
and erodes easily, but Eldey has not significantly changed in a century,* 
and the Icelanders, who are sensitive to tradition and history, and whose 
fowlers work with their fathers and sons, are positive that the garefowl 
ledge is still as it was. It was certainly easy, in 1949, to imagine the 
great razorbills bobbing buoyantly in the fuss of spray and breakers 
round the landing-places, clawing a foothold and waddling and 
struggling clumsily ashore. But they only did this at Eldey for fifteen 
years. In the first year, the year of the earthquake 1830, two boats 
took twenty or twenty-one skins for dealers; in 1831 twenty-four 
were taken; in 1834 at least nine skins and several eggs; in 1840 at 
least one tgg\ in 1841 three skins and one tgg (the tgg was probably 
laid by a female which laid an tgg taken in 1840, judging by their 
remarkable similarity). On a day between the second and fifth 
(most probably the fourth) day of June 1844 a boat of fourteen men, 
under the leadership of Vilhjalmur Hakonarsson, sailed the fourteen 

*Just after this was written, in April 1951, a large piece of Eldey's top did sWde off; 
the garefowl ledge was unaffected. 



SEA-BIRD NUMBERS AND MAN 75 

miles from Kirkjuvogur to Eldey; the sea was rough, and only three 
men could get ashore, SigurSur Islefsson, Jon Brandsson and Ketil 
Ketilsson. They found two garefowls and an egg. Ketilsson smashed 
the Ggg, because it was already cracked, and the others each caught 
and killed an auk. On their way home the men sold the skins to a 
certain Christian Hansen, who sold them to the bird-stufFer at Reyk- 
javik, Moller. Since that day no great auk has been certainly seen 
alive by anybody, anywhere. 

There is only one other place at which the great auk has been 
suspected to have bred; it is certainly the most remote and romantic 
of the lot — romantic because it is the first place in the New World 
to have been seen by an European. In 877 a Norwegian, Gunnbjorn 
Ulfsson, on his way to Iceland to settle, was driven west past Iceland 
by storms, to some skerries, beyond which was land. The land was the 
the east coast of Greenland, and the skerries, once thought to be 
what are known as Graah's Islands, at about the same latitude as 
the Snaefell Peninsula of Iceland, and now thought (G. Holm, 19 18) 
to be Leif's and Erik den R0de's Islands north-east of Angmagssalik. 
It was from Snaefellsnes that Erik the Red set sail in 982 to found the 
first European colony in the New World — and he navigated west to 
Gunnbjorn's skerries on his way. In the old sailing directions they 
are regarded as "midway between 'Greenland' (the Norse colonies in 
S.W. Greenland) and Iceland"; which is correct. Many fishermen 
and voyagers to Greenland after Gunnbjorn and Erik sailed to, or by, 
Gunnbjorn's skerries, and in the twelfth or thirteenth century at least 
one such voyager, according to the M.S. sagas of Iceland (Anon., 
1838, W. Preyer, 1862), discovered a great multitude of great auks 
on them. Between 1586 and 1596 the fisherman Latra Clemens from 
Adalsvik in Iceland is said to have taken a 'boatload' of garefowls 
here. There is no later record of great auks at this place,* and it 
may have become too ice-bound with the deterioration of climate 
at about that time. 

Such is the grim history of the great auk. As Salomonsen (1945) 
points out, the downfall of the great garefowl probably began when 
the Indians of the east coast of North America exterminated it on the 
mainland and neighbouring islands ; by the time the hungry sixteenth- 
century transatlantic sailors found it in the Gulf of St. Lawrence and 

* Grieve quotes a date 1652, but this refers to a voyage of David Danells on this 
coast, on which he did not visit Gunnbjorn's skerries, and could not have done so 
because of the ice. 



76 SEA-BIRDS 

Newfoundland it was probably already driven to skerries out of reach 
of the Indians' canoes. Maybe in prehistoric times the great auk 
also had a wider breeding-distribution in north-west Europe, or at 
least a very much denser distribution in Iceland-Faeroe-Britain. At 
the last, in its final miserable nineteenth-century years of slaughter, 
it was demanded for collectors (though while it was alive they did 
not pay much for it, contemporary accounts show). For years its 
passing was not known, and it was still sought high and low, by 
Steenstrup, Wolley, Newton, Grieve, Lucas; the devoted interest 
of these ornithologists only served to show that ornithology came not 
quite in time to save the auk, and that ignorance and greed are some- 
times more powerful than knowledge and truth. 

* ^ 4f 

The end of the great auk was the only extinction in historical 
times of a primary North Atlantic seabird; but a secondary sea-bird, 
the Labrador duck, followed it in 1875 or 1878. Man the ignorant 
killer was again the agent of its death, armed this time with a shotgun. 
The evidence against him, in this particular case, is circumstantial; 
for nobody knows much about the population of Camptorhynchus 
labradorius, except that within colonial times it never appears to have 
been great. Nobody knows where it nested, though it was probably 
on the Labrador coast of the Gulf of St. Lawrence; no doubt it suffered 
from nesting-time persecution by Indians as well as winter-shooting 
by the colonists in the Nova Scotia and eastern U.S. coast; it wintered 
south to New Jersey. 

Two North Atlantic sea-birds which were nearly exterminated 
by heedless exploitation are the diablotin of the West Indies, and 
the cahow of Bermuda, two closely-allied gadfly-petrels. The diablotin 
(or black-capped petrel), Pterodroma hasitata, still survives, probably 
in very small numbers, on Haiti and Dominica, while its close relation, 
P. cahow of Bermuda, now numbers probably fewer than a hundred 
individuals. But once these birds did not merely survive; they swarmed. 
The diablotin was first discovered by J. B. du Tertre (1654) on Guade- 
loupe; he thought it a rare bird of the mountains. In 1696 J. B. Labat 
(1722) describes a remarkable hunt for diablotins on the Soufriere 
of Guadeloupe, using eight-foot poles, hooked at the end, in the 
burrows; six men caught 213 in a morning. Already, Labat com- 
mented, the settlers were wiping the birds out. By the nineteenth 
century it was rare, and most of the surviving burrows on the Soufriere 
were destroyed by the great earthquake of 1847. But one was caught 



SEA-BIRD NUMBERS AND MAN 77 

by a dog on Guadeloupe "a few years" before 1891 (G. N. Lawrence, 
1 891). On Dominica, Labat recorded it in 1696, and it was known 
in 1 79 1, and recorded as "abundant" as late as ^.1858 (G. N. Lawrence, 
1 878) . But it seems quickly to have given way in the nineteenth century, 
for the Morne Diablotin, the petrel mountain of Dominica, was searched 
in vain for the birds by Ober (1880), Feilden (1890) and in 191 7 by 
Beck (Murphy, 1936). However, the diablotin reappeared on Haiti 
(Hispaniola) in 1928 and on Dominica in 1932; and in 1938 a bird 
was found alive in Haiti which had not long left the nest. Moreover, 
the diablotin has been seen at sea in the present century in the triangle 
West-Indies-Bermuda-Azores, and the survival of a small breeding- 
population upon some Caribbean hillside is scarcely a matter of doubt; 
it would be exciting to be the discoverer, or re-discoverer, of its present 
breeding ground. Probably a very small population has survived 
all through, hidden in the mountains on Dominica and on Haiti. 
But in Jamaica, where a dark form of the petrel existed on Blue 
Mountain, no specimen has been found on the old breeding-places 
since some years before 1891 (W. E. D. Scott, 1891). It is probable 
that man's introduced animals, including opossums and mongooses, 
may bear some responsibility for the diablotin's undoubted extinction 
in Jamaica and Guadeloupe, and extreme rarity in Haiti and Dominica. 
But it seems clear that Man himself bears most. 

Pterodroma hasitata has wandered to the North American seaboard 
or inland about a dozen times, as specimens from five of the United 
States and the province of Ontario in Canada show. It has actually 
been recorded in Britain; one was caught alive on a heath at South- 
acre, near Swafifham in Norfolk in March or April 1850. In the British 
list it is called 'capped petrel.' The story of the other rare petrel of the 
West Atlantic, the cahow of Bermuda (of which two skins only exist) 
is much the same. 

In 1603 the galleon of Diego Ramirez, a famous Spanish captain, 
sheltered in a Bermudan anchorage in a storm, and the crew found 
themselves among nocturnal petrels. The cahows were yelling fear- 
fully and eating squids, and it was only after some preliminary 
skirmishes with what some members took to be devils that the crew 
settled down to eating, drying and storing some thousands of the fat 
birds. Within a few years from this first known encounter Man had 
eaten all, or nearly all, the cahows, for by 161 6 the governor of the 
island tried to stop the killing to save the stock; but it was too late. 
There was no indication, after 1629, that any cahows had survived. 



78 SEA-BIRDS 

But on 20 February 1906, two hundred and seventy-seven years after 
the existence of the pecuUar bird had been last mentioned, a black- 
capped petrel with white under-parts was discovered in a rock- 
crevice on Castle Island, Bermuda, by Louis L. Mowbray. It was 
like no other petrel that had ever been seen, though it bore some 
resemblance to Pterodroma hasitata. With J. T. Nichols, Mowbray 
described the new bird in 191 6 as Pterodroma cahow. In the same year, 
though a few months later, R. W. Shufeldt described a new petrel 
from a large collection of bones gathered from the floors of the old 
bird-caves in Bermuda by Mowbray and others; he also believed 
that this was the old, real cahow. The issue had by then become 
somewhat confused, for Bermuda then harboured breeding colonies 
of shearwaters. There is no doubt that some of the nineteenth-century 
accounts of 'cahows' on Bermuda — such as those of J. M.Jones (1859) 
and S. G. Reid (1884) — refer to Audubon's shearwater, Puffinus Vherm- 
inieri. Both Jones and Reid alluded to their birds, not inappropriately, 
as Puffinus obscurus, an old synonym of both P. Vherminieri and P. 
assimilis. 

On 8 June 1935 a boy on a bicycle brought a bird to William 
Beebe (1935) in his research laboratory at New Nonsuch, Bermuda, 
from the lighthouse-keeper at St. David's. Beebe sent it to R. C. 
Murphy, who confirmed that it was the second known specimen 
o^ Pterodroma cahow. It was a young bird, probably only a few days out 
of the burrow, and had died by flying against the light. The bones 
of this bird were, rather luckily, preserved; and were identical with 
the sub-fossil and recent cave-floor material described by Shufeldt. 
So there is no doubt that Pterodroma cahow (frontispiece) is the old 
cahow; and that it survived and bred in 1935. 

In June 1941 a cahow was killed by striking a telephone- wire on 
Bermuda. In March 1945 F. T. Hall, stationed on Bermuda, found 
old bones, fragments of birds apparently killed by rats, and a partly 
disintegrated adult that had floated ashore. 

Murphy and Mowbray (1951) who recount this, were responsible 
for the uncovering of the cahow's present breeding-grounds in 1 95 1 . 
Study of this group of petrels had suggested that the cahow might 
have an early breeding-season, and their exploration of the islands 
off* Castle Roads occupied the period from 25 January to 10 February. 
On 28 January they found a cahow on an egg at the end of a six-foot 
horizontal burrow at the rear of a rocky niche on a much-eroded islet 
Eventually they found three occupied islets, one with perhaps nine. 



SEA-BIRD NUMBERS AND MAN 79 

another with three or four, and the last with one occupied burrow. 
Gurnet Rock, the type-locahty of the species, could not be visited. 
They conclude that there may be fewer than a hundred adult cahows 
surviving, and that there are not likely to be more. Much of the old 
nesting-grounds have been destroyed, and rats have established them- 
selves on some of the islets, where no burrowing tubenoses consequently 
now nest. Louis S. Mowbray (son of L. L. Mowbray) is now experi- 
menting with artificial burrows on some of the remoter, rat-free rocks 
to encourage breeding. Human exploitation seems to have made the 
first inroads on the cahow population, but its subsequent recovery 
has certainly been inhibited by other factors. Murphy and Mowbray 
conclude that "if a suitable alteration of present circumstances may 
eventually enable the cahows to spread to neighbouring islands well 
covered with soil, the future of a beautiful and historic sea-bird will 
be assured." 

!|e « * 

The history of the gannet in the North Atlantic shows well the 
transition from Man the predator to Man the husbandman and Man 
the protector. In the eighteen-thirties there were probably a third 
of a million individual adult gannets breeding yearly in the North 
Atlantic. By the end of the century the number was down to not 
much more than a hundred thousand. A diagram of the change in 
population is shown as Fig. 14, p. 80; it is based on the work of 
Fisher and Vevers (1943-44). The history can usefully start 
with the visit of J. J. L. Audubon to the Bird Rocks in the Gulf of St. 
Lawrence in 1833. He made no actual estimate of the number of 
occupied nests on this island (it was then much bigger than it is today, 
after erosion), but it has been possible to calculate from the size of 
the area occupied, and from the known density (one nest to just over 
a square metre) of this and other 'flat-top' gannet-colonies like Eldey 
and Grassholm, that Audubon saw a colony which probably then 
harboured between a hundred and a hundred and twenty-five thousand 
nests, or about two-thirds of all the gannets then living. 

Audubon learned from his pilot, Godwin, that the Labrador 
fishermen annually visited the Bird Rocks to get flesh to bait their 
cod-fish hooks. Godwin himself had visited the rocks, with the fisher- 
men, for ten years in succession, for this purpose ; and on one occasion 
"six men had destroyed five hundred and forty gannets in about an 
hour, after which the party rested a while, and until most of the living 
birds had left their immediate neighbourhood, for all around them, 



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SEA-BIRD NUMBERS AND MAN 8l 

beyond the distance of about a hundred yards, thousands of gannets 
wer^e yet sitting on their nests, and the air was filled with multitudes 
of others." Enough were taken to supply bait for forty boats. The taking 
of gannets for bait at the Bird Rocks went on until the end of the 
century (in 1898 the nests reached their lowest number, probably 
not more than 750), and in 1900 some gannets were shot on the nest 
and a couple of pails of eggs were taken. From 1904 the birds were 
protected by Government order, and in 19 19 the rocks were made a 
Federal Bird Sanctuary. Owing to the persecution, erosion of the 
gannets kept ahead of the erosion of the Bird Rocks, but during the 
present century the breeding-places have gradually become full up. 
Much reduced in area by erosion, they now hold fifteen hundred 
nests or more. 

In the sixty years of steady decrease of the world population (1834- 
94) the downward trend was primarily due to the fate of the colony 
on Bird Rocks. In about 1864, however, a remarkable upward trend 
got under way in south-west Britain. The first nests were found on 
the Bull Rock in Co. Cork in 1856 and on Grassholm in Pembroke- 
shire some time between 1820 and i860. The colony on the Little 
Skellig in Kerry was down to about thirty nests in 1 880, at a time when 
the trends in the other colonies was opposite, and after that date also 
increased; the present situation (1949) is that the Little Skellig is 
probably the second or third largest gannetry in the world, equal to 
that at Eldey in Iceland with about twelve thousand nests, and 
Grassholm is the fourth with eight or nine thousand. 

The world population began to recover not long after this trend 
in the south-west had begun to make itself felt; and more recently 
has been 'boosted' by the colonization of Shetland and an increase 
in Iceland. The St. Lawrence colonies have also recovered and new 
ones have started; in 1834 they held about 67 per cent, of the world 
population, in 1894 about 8 per cent, and in 1939 about 16 per cent. 
In 1864 the south-west Britain colonies held about 0.2 per cent, of 
the world population; in 1894 about 6 per cent.; in 1939 about 
19 per cent. The world's largest colony is now that at St. Kilda, which 
has remained constant, as far as the records show, at fifteen to seventeen 
thousand nests. We can reach our final conclusions on the numbers 
of the gannet by bringing up-to-date the remarks of Fisher and Vevers 

(1943-44) ' 

The great decrease of the world's gannets in the nineteenth century 

was primarily due to the activities of man; and the twentieth- 

E 



82 SEA-BIRDS 

century recovery is largely due to the relaxation of his predation, to 
the control of it, or to positive protective measures. In the history of 
the gannet man appears in the different roles of mass-destroyer, harv- 
ester, conservator and protector. When he has indulged in wanton 
massacre of gannets, such as at the Bird Rocks, probably at Little 
Skellig in its early days, the world population has seriously suffered. 
By thoughtless and heedless killing man has extinguished at least 
four colonies; Gannet Rock, Grand Manan (1871), Gannet Rock, 
Yarmouth, Nova Scotia (1883), the Perroquet Islands, N. shore 
Gulf of St. Lawrence (1887) and Lundy off the Devon coast (1909). 
He has endangered the colonies at Grassholm, Little Skellig and 
Bird Rocks at certain periods of their history. By mass destruction 
man reduced the gannet population of the world by about two-thirds 
in sixty years. 

At certain colonies, however, man has harvested gannets, their 
eggs, and their young for his own use, apparently without endangering 
the population. This applies to Ailsa Craig (Firth of Clyde) continu- 
ously up to about 1880; to the Bass Rock (Firth of Forth) up to 1885; 
to St. Kilda up to 1 910; to Sule Stack (west of Orkney) intermittently; 
to Eldey (Iceland) up to 1939; to Sula Sgeir (north of Hebrides), 
Mykines (Faeroes) and the Westmann Islands (Iceland) up to the 
present day. 

There is no doubt that at the majority of these colonies man has 
acted as an unconscious conservator. At Mykines and in the West- 
manns the inhabitants are conscious conserv^ators, for they never 
over-crop, and set an upper limit to their bag before killing. It 
seems true, however, that as Sula Sgeir man has sometimes over- 
cropped, and only the intervention of bad weather and wars has 
kept the raiders (from Ness in Lewis) away in some years, and allowed 
the colony to recover. 

So the gannet is now increasing; and there is no indication that it 
will not continue to do so. In the long run, it is likely to be food- 
supply that controls the numbers of the gannets, provided man con- 
tinues to leave them alone. There is no evidence that this supply is 
stretched in any way, anywhere in the gannet's range, at present. 

We append on page 83 a list of the world's gannet colonies, with the 
approximate numbers of their nests, in 1939, and of the east Atlantic 
colonies in 1949. 

On the Atlantic sea-board man now begins to play the role of 
conscious conservator, but he has not yet assumed it everywhere; 



SEA-BIRD NUMBERS AND MAN 



83 







Approximate number of nests 


Group 


Colony 


1939 


1949 


Remarks 


Armorican 


Rouzic, Brittany 


28 


77 


Founded 1939 




Ortac, Gasquets 





225 


Founded 1940 




Les Etacs, Alderney 





418 


Founded after Ortac 


S.-W. 


Grassholm, Pembs. 


5.875 


9,200t 




Britain 


Great Saltee, Wexford 





2 






Bull Rock, Cork 


575 


295 






Little Skellig, Kerry 


9,500 


12,000 




E. Britain 


Bempton, Yorks. 


4 


2 






Bass Rock 


4,374 


4,820 




W. Britain 


Great Scaur, Wigtownshire i 


100 


Founded 1939 




Ailsa Craig, Ayrshire 


5,419 


4,947* 






[Holy Isle, Arran. 12 


birds roosting and carrying 
breeding proved^ 


' nest-material 1949, no 


N. Britain, 


St. Kilda 


16,900 


17,035 




Norway 


[Rockall. Up to I ^ birds near rock 194 


I ; 12 carrying nest-material 1 949, 


& 




no breeding] 






Faeroes 


Sula Sgeir, Lewis 


3,970 


6,182 






Sule Stack, Orkney 


3,490 


2,010 






Noss, Shetland . . 


1,830 


3,150 


(1946) 




Hermaness, Shetland 


2,611 


3,750 






Rundo, Norway 





8 


Founded c. 1 946 




Mykines, Faeroes 


1,473 


[1,473] 


not counted 1 949 


Iceland 


Westmann Isles . . 


4,359 


5,538 






Eldey . . 


9,328 


1 1 ,000 






Drangey . . 





I 


Founded 1949 




Grimsey . . 


45 





Deserted since 1 946 




RauSinupur 





6 


Founded 1944 or 1945 




Skrudur . . 
Total East Atlantic 





150 


Founded 1943 




69,782 


82,394 




West Atlantic 










Bird Rocks, Magdalen I 


s. 1,250 




(1934) 




Bonaventure I., Quebec 


6,800 








Gull-cliff Bay, Anticosti 


[. 496 




(1940) 




Gape St. Mary, 










Newfoundland 


4«394 








Bacalieu I., Newfoundla 


ad 200 




(194O 




Funk I., Newfoundland 


100 




(1940) 



Total West Atlantic 



13,240 



WORLD TOTAL (c.1939) 83,022 



*but 6,579 in 1950: a fluctuating colony. 

fbut c.8,000 in 1951 (R.M.L. & P. Scott), c.8,500 in 1952 (R.M.L. & D. Surrey- 
Dane), possibly exaggerated in 1949. 



84 SEA-BIRDS 

and before we can reach a discussion of his present protection activities 
we have to consider yet further some aspects of his past predation and 
exploitation of sea-birds. One special kind of predation was extremely 
damaging — the trade in plumes. The terrible depopulation and even 
extinction resulting from it has been vividly described by many 
writers, particularly in the early publications of the Royal Society 
for the Protection of Birds in Britain and the Audubon Society in 
the United States. The miserable business, which still continues to 
a certain extent in Asia and the^Pacific, started in the nineteenth 
century and in Britain marched closely with the rise of Victorian 
fashion. Indeed, it no doubt dictated rather than followed any 
Victorian fashion. At one time it seriously menaced British bird 
populations — for instance, the persecution of kittiwakes on the big 
Flamborough colony in the 1860s resulted in a fighting speech by 
Alfred Newton, the pioneer ornithologist, to the meeting of the British 
Association for the Advancement of Science in 1 868, which resulted, 
in turn, in the Sea Birds Protection Bill of 1869. 

Terns however still came to some of the London sales in the first 
decade of the present century in alarming numbers from abroad, such 
as the sooty tern and the wonderful fairy tern, Gygis. 14,400 were sold 
on 14 April 1906; in 1908, 18,000 on 11 February; 16,700 on 14 
April; 16,500 on 10 June. It was not until 1922 that the Importation 
of Plumage (Prohibition) Act was passed and stopped, at least in 
Britain, this trade in dead birds for human decoration. 

In the United States the depredations of plume traders on the 
Atlantic coast is described in detail by A. C. Bent (1921). Hunters 
killed vast quantities of terns and took their eggs. On the coast of 
Virginia in the last decade of the nineteenth century and the first 
decade of the present century, the large colonies of gull-billed, royal and 
little terns were virtually annihilated, and similar destruction of terns 
was recorded in various places from Louisiana and Florida north to 
the New England states. As Bent points out, the most pitiful tale of 
destruction is the story of Cobb's Island and other colonies on the 
Virginian coast. In 1875 the Uttle tern was "astonishingly abundant" 
all along the Virginian coast, and particularly on Cobb's Island. 
But their destruction started soon afterwards. As Bent says, "Profes- 
sional collectors for the millinery trade spent the greater part of the 
breeding seasons on the island, and killed the innocent birds in almost 
incredible numbers. The resident fishermen and oystermen also found 
it a lucrative occupation. As many as 1,200 birds were often killed 







*i?a 



.r<p*<i 



■^>ife-r^ 



i*jr> 



P/a/^ Ffl. Part of the gannetry at Grassholm, a bare windswept island off South Wales. It 
has increased from about 63 to 8,500 pairs (1952) in a hundred years (/?. M. Lockhy) 

Vb. The gannetry on the cliffs of Bonaventure Island in the Gulf of St. Lawrence, Canada 

'.Allan D. Cruirkshank from .Vatinnal A'uiihin Sorirtv) 









K- '■::'". ■ > 




Roger T. Peterson 



Plate VI. Brown Pelican, St. Petersburg, Florida, U.S.A. 



SEA-BIRD NUMBERS AND MAN 85 

in a day, and one of the residents who had taken part in the slaughter 
himself told me that as many as 100,000 terns were sometimes killed 
in a season." 

By 1902 the little tern had gone. Fortunately this island and other 
places were shortly afterwards recolonised, possibly as a result of the 
election of Theodore Roosevelt as President of the United States in 
1901! As Roger Peterson (1951) writes, "During his term of office, 
which meant so much to the wild creatures, his pen created 38 federal 
refuges. Ten years later, when he visited one of these on the coast 
of Louisiana, he remarked, as a cloud of royal terns arose from their 
eggs, that this sight alone was worth all the effort." 

Of all sea-birds, terns are the most unpredictable in their social 
breeding habits. The numbers of occupied nest sites, even at ancient 
and traditional colonies, fluctuate very much more than the numbers 
at traditional colonies of other sea-birds such as gulls, auks or gannets. 
Sometimes a very large colony with some thousands of nests may 
desert in mid-season; sometimes it may establish its headquarters 
some miles away from the place where it did so in the previous season. 
A glance at the table will show the reader the fluctuations in occupied 
nests at the principal Sandwich and common tern colonies in Norfolk. 
These colonies have been since the early 'twenties under the strictest 
protection, and it is almost certain that the changes are due to factors 
outside human control. They are certainly not due to human predation 
and disturbance, but some of them may be due to fluctuation in food 
supplies, others to weather; of course, changes in food supplies can 
be a consequence of weather. Terns appear to be very sensitive to 
changes in the environment; more so than any other family of sea-birds. 
Nevertheless, it seems perfectly clear that there has been a really 
important recovery in the conditions of these sea-birds of the North 
Atlantic during the present century and that this recovery is due to 
protection. It is one of the many indications that the bird protection 
movement which has been active on both sides for more than half a 
century, has now won appreciable results. We can, for the first time 
in human history, say that we have improved the number and variety 
of our wild birds for the aesthetic satisfaction that they give us and for 
no reason whatsoever connected with commerce or profit. 

It is worth giving details of these changes in the fortunes of the 
terns. The gull-billed tern, for instance, has colonised Florida in the 
last twenty years, and on the Old World side of the Atlantic has spread 
from its ancient isolated nucleus in Denmark to Germany and Holland 



Tern's Nests between Branc aster and Salthouse, 

Norfolk, 1920-50 

Numbers approximate minima of occupied nests (figures in brackets interpolated) 





SANDWICH TERN 


COMMON TERN 




Salt- 


Blake- 


Scolt 




Salt- 


Blake- 


Scolt 






house 


ney 


Head 


Total 


house 


ney 


Head 


Total 




to Cley 


Point 


I. 




to Cley 


Point 


I. 




1830 










+ 


+ 






1831,1838 












+ 






1847 












all 
common 






I85I 












+ 






1898 












left 
{rats) 






I90I 












140 




140 


I9II 












rats 






I9I2 












350 




350 


I9I4 




some 








600 




600 


I9I6 












badyr. 






1920 





I 





I 


20 


? 





20 


I92I 





2 





2 


100 


250 





350 


1922 


90 


9 





99 


610 


2000 


17 


2627 


1923 


483 


100 


59 


642 


200 


2000 


315 


2515 


1924 


403 


300 


40 


743 


420 


(700) 


600 


1720 


1925 





8 


653 


661 


385 


700 


850 


1935 


1926 


50 


100 


515 


665 


90 


400 


500 


990 


1927 


200 


500 


21 


721 


218 


400 


584 


1202 


1928 


60 


1000 


75 


1135 


60 


700 


300 


1060 


1929 


271 


1503 


15 


1789 


75 


(700) 


382 


1157 


1930 


225 





500 


725 




700 


700 


1400 


I93I 


275 


4 


203 


482 


+ 


1000 


500 


1500 


1932 


592 


28 


204 


824 


+ 


1459 


550 


2009 


1933 


738 





38 


776 




1543 


550 


2093 


1934 


827 





64 


891 




1962 


450 


2412 


1935 


1000 


10 


37 


1047 




2177 


1347 


3524 


1936 


730 





114 


844 




1971 


1647 


3618 


1937 


1000 





214 


1214 




2231 


1440 


3671 


1938 


1000 





285 


1285 


+ 


1923 


2470 


4393 


1939 


1000 


3 


II 


1014 




2000 


2140 


4140 


1940 


1000 


15 


649 


1664 




2157 


1700 


3857 


I94I 


1000 





446 


1446 




2000 


1700 


3700 


1942 





50 


1042 


1092 




1000 


1700 


2700 


1943 





2 


2000 


2002 




2000 


1700 


3700 


1944 


20 


3 


1000 


1023 




(1500) 


1700 


3200 


1945 





1000 


400 


1400 




(1500) 


1400 


2900 


1946 





2 


1900 


1902 


8 


1400 


1400 


2808 


1947 





30 


50 


80 




1550 


1000 


2550 


1948 





42 


175 


217 




1500 


1000 


2500 


1949 





51 


474 


525 


18 


1650 


1000 


2650 


1950 





194 


50 1 


244 


29 


2122 


450 


2572 



Sources : W. Rowan (1915), B. B. Riviere (1930), Marples and Marples (1934), 
Annual Reports on Bird Protection in Norfolk (Norfolk Naturalists' Trust, 
published in Trans. Norf. Nat, Soc), and various notes in Brit. Birds and the Zoologist. 
4- a few pairs 



SEA-BIRD NUMBERS AND MAN 87 

in the 1930's, and, within the last few years, to south-east England. 
These new colonies are not yet well-established, but at least there is 
a tendency to recovery in a species which once appeared to be declining 
to extinction. Unfortunately the Caspian tern has not yet returned 
to the German North Sea coast where it became extinct some time 
during the first World War. In both Britain and the United States 
both the common and arctic terns have suffered a good deal from 
egging, mainly in the nineteenth century and both World Wars, and 
from the plume trade, though only perhaps slightly from this in Britain. 
Undoubtedly both have had a general recovery in the present century, 
though with marked fluctuations. It is doubtful whether, in any 
year in the present century, there have been many more than seven 
thousand common terns' nests occupied in England and Wales, and 
likely that over half of these have been in Norfolk, where a great 
recovery immediately followed the institution of the coastal sanctu- 
aries in 1920. However, the colony on the Isle of May in the Firth 
of Forth had, in 1936, nearly as many nests as all the Norfolk sanctu- 
aries put together — about 3,400 against 3,618. There is an even larger 
colony in Strangford Lough in County Down in Ireland, and the 
common terns' nests in the whole of this very suitable county may 
occasionally amount to ten thousand. 

The arctic tern does not appear to have increased in England and 
Wales, as has the common tern, though there is no evidence that it has 
decreased. This is probably because England is at the southern limit 
of its world breeding-range, and the limit itself may be moving 
gradually northwards, as is the case with many arctic and subarctic 
species, owing to the present climatic amelioration. Certainly of late 
the arctic tern has become very desultory at its colonies in the Scilly 
Isles. It is doubtful whether, in the present century, more than three 
thousand of its nests have been occupied in England and Wales, 
and likely that more than half of these have been on the Fame Islands. 
In the rest of Britain it outbreeds the common tern in most parts of 
Scotland and the exposed part of Ireland. 

The roseate tern has made a fine recovery in the British Isles, 
where the species was first discovered, in 181 2, and which now con- 
stitutes its European headquarters ; its extraordinary breeding distribu- 
tion appears to be of a relict type (Fig. 16, p. 90). The tendency of such 
distributions is, of course, to become further restricted. However, the 
trend has been reversed in Britain. It is doubtful if there were a 
hundred nests or eight colonies in the whole of Britain in any 




Fig. 15 
Breeding distribution of 
{a) common tern and (b) 
arctic tern in England. 
There are also breeding- 
records of the common 
tern from Staffordshire, 
near Burton-on-Trent in 
1952 and 1953. 



rELONG. 



not since last century 
present, but breeding not 

proved 
under 10 nests 
under 100 nests 
under 1000 nests 
over 1000 nests 




rELONS. 



SEA-BIRD NUMBERS AND MAN 89 

year in the nineteenth century. At the turn of the century it was 
possible that the only nests in Britain were one or two on the Fame 
Islands, in Northumberland. At present there are twenty colonies or 
less, which are not likely to have much more than a thousand occupied 
nests in any one year, about one-third of which are in Anglesey and 
at least one-third of which are in County Down. Outside Britain a 
few hundred pairs of roseate terns breed on islets off the coast of Brit- 
tany; and in 1951 R. M. L. and the warden, H. Lomont, of the Reserve 
zoologique, found two pairs nesting in the Camargue of southern 
France. 

Perhaps the best example of a tern which protection has helped 
(but whose fluctuation, and desultory breeding, protection has not 
prevented) is the Sandwich tern. The most spectacular increases in 
the population of this bird have been in Holland, where at present it 
is likely that ten times as many nest as in Germany or Britain. Indeed, 
round 1940 there may have been forty thousand nests on this fairly 
short coast, which is the culmination of notable increases during the 
first half of this century, which have been primarily due to protection, 
in which the Dutch excel. The numbers of the colonies have fluctuated 
and, as is also true in Germany and Britain, the population has 
transferred itself from one part of the coast to a neighbouring part in 
subsequent successful seasons. In Britain it is probable that the 
Sandwich tern was extinguished at its original haunts near Sandwich 
by eggers rather than by plume traders. It has never returned. In 
Norfolk the situation (see table, p. 86) in the sanctuaries provided 
for terns by the National Trust and the Norfolk Naturalists' Trust 
shows a triumph for bird protection, which has established the species 
in large numbers, though it has clearly been unable to control its 
fluctuation. A colony on the Fame Islands in Northumberland has 
survived egging by collectors for human food and for oologists' cabinets 
in the nineteenth century, and while it does not at present attain the 
numbers it reached in the last century, it seems to have (rather sur- 
prisingly) consistently remained at about a thousand nests. In spite 
of some suitable nesting space being occupied by arctic and other 
species of terns, the Sandwich tern seems to have started new colonies 
farther north, for the species seems to be steadily building up its num- 
bers (since 192 1) in the Firth of Forth. In Ireland an increase which 
was noticeable early in the present century may not continue. In 
Jerse/ it is numerous in some years; in 1952 the colony of 250 pairs 
suddenly disappeared after laying eggs. 



Fig. 1 6 

Breeding distribution of the roseate 

tern, Sterna dougallii. Dots represent 

some known breeding-places 




05 06 07 08 OQ 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 




. -i — I — I — i — I — I — I — \ — I — \ — I — I — I — I — I — I — I — I — I — \ — I — I — I — I — I — I — I — I — I — I I 1 r~i I I I I 11 I r 
0506 07 08 0910 II 12 13 14 15 lb 17 18 19 20 2122 23 24 25 26 27 28 29 303132 33 3435 36 37 38 39 40 4142 43 44 45 46 47 

Fig. 17 
The populations (occupied nests) of the Sandwich tern colonies of the German 
North Sea coast (and Jordsand in Denmark) . Data mostly from H. Schulz 
(1947), for years 1905-47. Dark shading: population. Light shading: station 

occupied but population not recorded. 



■■■^ 



92 SEA-BIRDS 

We find from the detailed account of Schulz (1947) that since 1819 
sixteen different sites have been occupied on the coast of Germany, 
sometimes only three, and never more than seven at once (or six in 
the present century). The only colony which has been continuously 
occupied since that date is on Norderoog in the north Frisian Islands; 
this has also always (except in one year) been the largest. In 181 9 the 
(? over-) enthusiastic Naumann estimated the numbers breeding on 
Norderoog as "upwards of half a million!" In the eighteen-seventies 
it was twice alleged that Norderoog had ten thousand nests; but in 
the present century estimates which were probably more careful have 
given a maximum of about six thousand nests in 19 15- 17. The most 
recent peak was 4,215 in 1943, and only four times in the last half- 
century have under a thousand nests been found. At present Norderoog 
accounts for all but a few hundred of the German Sandwich terns' 
nests, and the only other regular colonies are on Wangerooge and 
Liitje Horn. Since 1943 (4,215 nests) the Norderoog colony has 
decreased, and only 576 sites were occupied in 1947. A glance at 
Fig. 17, which shows the occupation of Sandwich terneries on the 
German North Sea coast since 1905, and their population in most years, 
will persuade the reader at once that Sandwich terns share desultory 
and unpredictable breeding-habits with the rest of their family, 
and that along a stretch of coast there is much transference of breeders 
from one station to another in successive seasons. 

* * * 

So far we have been dealing mostly with cases where greed has 
blinded the human predator to the consequences of his act, and where 
conscious acts of altruistic legislation have helped to save the species. 
However, there are situations in which the human communities have 
depended, and indeed, still depend, on wild bird populations for much 
or all of their protein supply, and have entered upon a custom of 
annual cropping of the colonies which has resulted in no detectable 
change in the status of these colonies other than can be expected with 
natural fluctuation. Indeed, there are several cases where, over many 
years, there has been a general trend of increase in a regularly exploited 
sea-bird population. 

Anybody familiar with the history of St. Kilda or with the existing 
situation in the Faeroe Islands and Iceland wall have discovered a 
situation completely different from the sorry story of greed and blood- 
shed associated with the eggers and plume-hunters of Florida, the 
Carolinas and Virginia, the Asiatic raiders of the Pacific islands, the 




Plate VII, Shags make use of the broader chff ledges: Kittiwakes build in the narrow dis- 
continuous niches (the young are in their first or tarrock plumage) (C. A. Gibson-inil) 




'o 






a 
m 

bo 



I 

<u 

c 

Q 









SEA-BIRD NUMBERS AND MAN 93 

hungry seamen of the early voyages 'o the Gulf of St. Lawrence. 
It is not, of course, inevitable that a resident human community 
comes into harmonious balance with the sea-birds which he exploits; 
but besides the places we have mentioned, it is likely that such is also 
the case in West Greenland, and on Baffin and Bylot Islands, where 
the Eskimo communities have a long fowling tradition. It is also 
probable that in somcotropicah islands the native populations have 
arrived at an harmonious predation of sea-birds. 

There are many accounts of the history of fowling, notably that 
of H. A. MacPherson (1897). In Britain the two main fowling com- 
munities have been the eggers or "dimmers" of the Flamborough 
cliffs in Norfolk, who descend the precipices of Bempton and Speeton 
on ropes to collect eggs, particularly those of guillemots, and the 
now extinct community of St. Kilda, which continued its fowling 
activities until it left the islands in 1930. 

The St. Kildans lived very largely on birds. From all the 
accounts (and there are many) the average St. Kildan ate one bird 
nearly every day throughout the year. The birds chiefly taken were 
fulmars, gannets and puffins. In the century 1829- 1929, the St. 
Kildans took an average of 115 fulmars a year per inhabitant (min. 
100, max. 130). The greatest total annual catch reliably reported is 
12,000 from the years 1829-43, when the human population averaged 
about 102. Even in 1929, the year before the evacuation, when only 
about 32 natives remained on the islands, 4,000 fulmars w^re taken. 
Most were young, taken between 12 and 26 August when sitting, 
fat, heavier (and more edible!) than their parents, on their cliff-ledges, 
but some were adults. The St. Kildans also noosed adults in March, 
and took a few eggs in mid- and late May. It seems likely that in most 
years they consumed half the reproductive output of the entire St. 
Kilda fulmar population. 

The gannet colony on Boreray, Stac Lee and Stac an Armin, the 
great north rocks of St. Kilda, is the largest in the world. In 1939 
nearly 17,000 and in 1949 about the same number of nests were 
estimated to be occupied ; about a fifth of all the gannets in the North 
Atlantic. Martin Martin certainly exaggerated the total crop of 
gannets taken (22,600 in 1696, he said), and it w^as the careful N. 
MacKenzie who showed that before 1829 never more than 5,000 
young were taken, and never more than 2,000 from 1829 to 1843. 
In 1 840 the crop was c. i ,600 young. But the crop was not only of young; 
from their arrival on the cliffs the adult gannets were taken, and their 



94 SEA-BIRDS 

eggs; thus i,ioo adult gannets were taken in a single night in June 
1847, ^^^ i^ April 1885 (probably before most eggs had been laid) 
660 were taken in two nights. The crop of young in 1895 ^"^^^ high — 
3,200; but only 300 young were taken in 1902. This is the last record 
of the taking of young. On 14 May 1902 the top of Stac Lee was 
cleared of gannet eggs. 600 adults were caught in the spring of 1910 — 
the last record we have. St. Kildans thought adult gannets, when 
arriving fat on the cliffs, and taken in March, were good eating — 
but not later in the breeding-season. They had a high opinion of the 
goodness of the eggs.* The "gugas" were held to be excellent, an 
opinion shared widely in the Lewis (and even in North America, 
whither salted gugas are sent to Lewisian emigres at Christmas) and 
by the writers of this book, who have tasted them in Scotland and the 
Faeroes. 

The Manx shearwater, which nests on Dun and Soay, on a slope 
of giant talus on Hirta known as the Carn Mor, and probably at the 
Cambir and other places on Hirta, was not much exploited. Mac- 
Kenzie (1905) in 1829-43 says the young were relished, and that the 
eggs and adults were taken; in Dixon's time, in 1884, they were hunted 
at night; George Murray (unpublished diary) records that on 9 April 
1887 shearwaters were taken from their burrows with the aid of dogs. 
By the turn of the century the .St. Kildans were taking shearwaters' 
eggs for collectors and dealers, but not eating them. 

*The St. Kildans had somewhat different ideas from the rest of the world abou 1 
the relative palatability of eggs. H. B. Cott (1948, 1949) submitted a large number 
of the eggs of wild birds to the Panel of Egg Tasters at the Low Temperature Research 
Station at Cambridge: they found those of the gannet "relatively unpalatable," 
thus disagreeing with the St. Kildans. But when, in later experiments (1951, 1952) 
Cott used hedgehogs and rats as tasters he found gannets' eggs second only in a 
hierarchy of many species! Certainly the St. Kildans valued gannets' eggs to the 
extent of making for years annual expeditions in April and May, involving the 
sensational climbs of Boreray and Stac an Armin, to gather them. 

In the eighteenth century, at least, no gannet eggs were taken on Stac Lee, which 
was left to produce young. These young could then be cropped before those derived 
from replacement-eggs on the other rocks. 

Martin has an amusing passage about the impact of the gannet's egg on the 
outsiders: "The eggs are found to be of an astringent and windy quality to strangers, 
but, it seems, are not so to the inhabitants, who are used to eat them from the nest. 
Our men upon their arrival eating greedily of them become costive and feverish; 
some had the hemorrhoid veins swelled. . . . They preserve their eggs commonly 
in their stone pyramids [cletts], scattering the burnt ashes of turf under and about 
them, to defend them from the air, dryness being their[only preservative, and moisture 
their corruption; they preserve them six, seven or eight months, as above said; 
and then they become appetizing and loosening, especially those that begin to turn." 



SEA-BIRD NUMBERS AND MAN 95 

The egg of the razorbill, writes MacKenzie, "when fresh is con- 
sidered very good eating, but the bird even when in condition only 
fairly so." The razorbill was not important in St. Kilda fowling. 
Most of its colonies were fairly accessible to the St. Kildans, but they 
took little of them, save a few basketfuls of eggs a year. Adults were 
usually stripped of their feathers, and their plucked bodies put to the 
fields as manure. 

The guillemot is much more important. MacKenzie writes "I 
have seen seventeen baskets full of eggs taken at one time from Stack- 
biorrach [Stac Biorach, a slender pillar 236 feet high out of the sea 
between Hirta and Soay], and at another time in the same season 
fourteen. These baskets hold each about four hundred of these eggs. ... * 
These eggs are very good eating when fresh. After they are incubated 
for a few days most of the egg appears, when boiled, to be changed 
into a rich thick cream, and in this condition they are also relished. 
Sometimes eggs, not only of this species but of some others which have 
not been hatched, are found late in the season. Some of these when 
cooked look like a piece of sponge cake, have a high gamey flavour, 
and are esteemed a great delicacy. Others are as bad as the most 
vivid imagination can depict." The adults were not thought good to 
eat except when they came in to the rocks, fat, in March and April, 
when they were caught by an imaginative device, described later 
(P- 97) > they were mostly used as a source of feathers and fertilizer. 
Many blown eggs were sold to tourists. 

More puffins were killed on St. Kilda than any other species of 
bird. While the St. Kildans' opinion* of its eggs may have been 
doubtful, or not unanimous, there was no doubt about their attitude 
to the adult. "The puffin," says John MacGillivray (1842), who visited 
St. Kilda in 1840, "forms the chief article of food with the St. Kildans 
during the summer months, and is usually cooked by roasting among 
the ashes." It was also the primary source of feathers; its feathers 
commanded a higher price from the laird's factor than those of the 
fulmar. Often the puffins were captured by women; Sands (1878) 
describes how on 15 July 1875 a number of young women were left 
on Soay for three weeks purely to catch puffins for feathers; on 
16 July seven more were left on Boreray for the same purpose. Sands 
also calculated that at least 89,600 puffins were killed in 1876. Connell 
(1887), on his visit in 1886, may be recording a change of human habit 

♦These figures are borne out by later accounts, though Dixon's suggestion "the 
natives gather the eggs literally by boatloads" is an exaggeration. 



g6 SEA-BIRDS 

when he states that "in an overwhelming majority of cases the puffin 
is killed for its feathers, and the carcass is simply thrown away, 
going usually to enrich the soil." Certainly when Steele Elliott (1895) 
visited St. Kilda in 1894 the 4,800 lbs. of feathers produced a year 
were largely composed of those of puffins, and may have been derived 
from about 90,000 birds; Sands's estimate of 1876 may have been no 
exaggeration. However, by 1898 and 1899 (Heathcote, 1900) nothing 
like 90,000 were being killed, though some thousands were taken 
every year. Feathers had decreased in value. "The St. Kildans eat 
puffins when they cannot get fulmars," Heathcote wrote. By 1902 
feather-taking was finished, and puffins were taken for food only. 
Wiglesworth (1903) said that the discontinuance of feather-taking 
has "caused the birds to multiply to such an inordinate extent, that 
they are doing serious damage to the pasturage by riddling the hill- 
sides with their burrows." This may have been somewhat of an 
exaggeration; the good grazing-ground of St. Kilda has not been 
burrowed into yet by a single puffin. The puffin was still being captured 
for food in 191 o and 191 1 (Clarke, 1912b), and probably continued 
to be so, for this purpose only, until the evacuation. Certainly the men 
were out killing puffins on 22 April 1927, the day after J. Mathieson 
(1927) had arrived. 

The methods of fowling on St. Kilda were straightforward enough, 
though one or two of their inventions were ingenious. Manx shear- 
waters were hunted at night, among the boulders of the Carn Mor 
and other places; as they landed on the ground and shuffled into 
their burrows they were easy to take with lights. Puffin-nesting was 
largely women's work. Dogs helped them find occupied nests under 
the turf and boulders of the six great puffinries of St. Kilda (the north 
face of Conachair, the north slopes of Dun, Carn Mor, the sides of 

*The St. Kildans appear to have disagreed with the rest of us about the taste of 
the egg of the puffin. Although the puffin is by far the most abundant bird on St. 
Kilda (MacKenzie, who was not prone to exaggerate, said "I estimate that there 
cannot be fewer of them than three millions" — and from Fisher's own experience 
of the St. Kilda puffin population he is sure he was right), its eggs were not sought 
like those of the other auks, guillemot and razorbill; yet sought they were, as 
MacKenzie records, and Connell, Murray and Wiglesworth after him. It is probable 
that puffin eggs were not collected assiduously because they were usually too deep 
in burrows; some recorders, like Dixon and Sands, who took evident pride in the 
completeness of their accounts, do not mention their taking, though they mention 
the taking of most other eggs ; it seems likely that the puffin egg was near the limit 
of tolerance of even the St. Kildan palate. That this palate was different from ours 
is clear; tradition and practice had evidently made it so: but even St. Kildans 
refused to eat the eggs (or the flesh) of the shag, or the flesh of the oystercatcher. 




C. A. GibiJii-llid 

Plate IX. A Guillemot cliff in Shetland. The topmost bird is a bridled individual (note 
" spectacle " round the eye). The bird {lower right) has been splashed with mutings from 

above 



.«'---';--^^ 



•**K,- 







^*<«^^;J^ 





---:-li: 



#*::::*t 



P/fl/^ Za. Fulmars and {centre) Great Snearvvater, Rockall, jane, 1948 (^. M. LofWfj-) 

b. A flock of Manx Shearwaters assembling off Skokholm (seen in back- 
ground) (^- ''\^' Silnmn) 



*'^ 




' V^ 



V 



■ /'V/" 



SEA-BIRD NUMBERS AND MAN 97 

the Gambir, Soay and Boreray), each of which is probably larger than 
any other puffinry in Britain; and they dug and dragged the birds 
out with a long arm. The men made horsehair nooses stiffened with 
bits of gannet-quill at the end of tapering bamboo poles from 6 to 
15 feet long, which they gently edged over the necks or under the feet 
of puffins and razorbills sitting about on turf or rocks, and of fulmars, 
guillemots, and even gannets on their eggs; and snatched the bird 
to them. Skilled workers could catch several hundreds of birds a 
day this way. Gannets were stalked asleep before dawn, and seized 
by the neck. One method of catching guillemots early in the season, 
when they came to the ledges but had not laid, is described by the 
accurate MacKenzie: "Two men will go to a likely place and as soon 
as the birds have left the rocks in the twilight one of the men will 
lower the other by a rope to the ledges which they have observed to 
be most thickly peopled. Then he has to wait all night while the birds 
are away feeding. Just before the earliest dawn he hides himself as 
close to the edge of the rock as possible, and holds up something white, 
as a handkerchief, on the rock beside him. The first comer seems to 
think that this is a still earlier arrival, and settles down beside it. 
It is at once pounced upon, killed, and held up in a sitting position 
in order to induce the next comers to settle down beside it. They 
return in little flocks from half a dozen to a dozen, and out of each the 
fowler may catch two or three, or if lucky even more. He goes on 
in this way till it gets so light that no more will settle. Sometimes he 
may not be successful, but in general he can catch from sixty to seventy." 
It was usual to try this dodge only once at each favoured ledge; the 
fowler went the rounds of the traditional stances. Other accounts 
show that they sometimes covered their heads with a large white 
sheet, to simulate a whole guano-white ledge rather than the flash- 
white underparts of a sitting bird. 

MacKenzie describes the special St. Kilda puffin-snare or puffin- 
gin (used for this bird alone): "It consists of about a fathom of stout 
cord to which hair nooses, about nine inches long, are fastened at 
intervals of three or four inches. This is stretched out on any boulder 
or ledge which the birds are at the time frequenting, and fastened at 
the ends. The nooses along the sides are then carefully opened out 
to a diameter of about an inch and a half. The birds which have been 
disturbed are soon back again, and, being restless little fellows, it is 
not long before some of them have got their feet entangled in the nooses. 
Three or four are generally caught thus before the snare has to be reset. 

H 



gS SEA-BIRDS 

Sometimes very many more are caught, for the puffin is a very pug- 
nacious Httle fellow, and when he finds himself caught attacks his 
neighbour. In this way a general fight is started, during which many 
are caught. On a suitable day a person with four or five of these 
snares, which are as many as he can attend to, may kill several 
hundreds." 

The main killing, of course, was at the autumn collection of young 
birds. Their necks broken, the young fulmars were tucked, heads 
through belts, round the waists of the fowlers, young and old, men and 
women; young gannets were often thrown down to the sea five 
hundred feet or more from the heights of Stac Lee or Stac an Armin 
to be collected by men in the boats waiting below. It is interesting to 
compare the tools of the St. Kilda fowler with those of other North 
Atlantic seafowlers. In the Faeroes, is found the fleygastong, which 
looks like a three-foot lacrosse net on the end of a 12-foot 
pole. It is held by the fowler inconspicuously on the ground, at a 
traditional catching-place, and swept up skilfully to intercept a flying 
puffin or fulmar. Faeroemen also drag puffins from their burrows 
with an iron hook on the end of a two-foot stick, the lundakrok, and 
also dig out burrows with a trowel of traditional design. The Jieyg 
does not appear to have been invented or used at St. Kilda, though 
it was in use in Orkney in about 1808; and, quite independently, 
the Aleut inhabitants of the Commander Islands, in the North Pacific, 
developed d. Jieyg, hooped like a giant butterfly net for catching Lunda 
cirrhata, the tufted puffin. The nearest the Hebrideans got to the 
Jieyg was a simple pole, with which fowlers smote or attempted to smite 
auks in mid-air, sometimes with fair results; and the nearest the 
Faeroeman has got to the St. Kilda puffin-gin (used on land) is a 
raft set with hair-nooses, anchored in a fiord to snare auks, decoyed 
by stuffed skins; this device appears to be an Iceland invention. 
The lundakrok, or puffin-gaff", was never used in the puffin-burrows 
of St. Kilda, though, as Alex. Ferguson tells us a pointed stick was 
used to tear the roof of a burrow shown by a dog to be tenanted. 

Egging and young-bird-fowling has also been carried on in Orkney 
and Shetland, and in Pembrokeshire, though only desultorily in the 
present century. It was never regarded as a very important source 
of food. Apart from this the only other traditional fowling in Britain 
which may now continue is the annual expedition to the gannet 
colony of Sula Sgeir, which is undertaken by the men of Ness in Barvas, 
the northernmost parish of the Lewis. The September expedition of 



SEA-BIRD NUMBERS AND MAN gg 

the men of Barvas was made until recently in a 40-foot skefia or 
'sgoth,' a direct descendant of the old Norse galley, the only boat 
of its type remaining. The men landed on the east side of the island 
and dragged their boat up its rocky side. They spent about a week 
among the gannets, living in an ancient stone hut and killing the young 
ones by clubbing. They took them for human food, dog food and even 
cattle food in winter, splitting and salting the gugas. It is possible 
that at certain times, including years of the present century, since 
the custom of raiding was noted in 1549, the men of Barvas have 
over-cropped. However, the colony had a good rest during the war 
and (see p. 83) has considerably increased. We see no reason to 
depart from the view expressed ten years ago by one of us and H. G. 
Vevers, which was this: "We are not convinced that absolute protection 
of this colony is necessary, or indeed desirable in view of the very 
ancient custom of taking gannets here after a 45-mile journey in an 
open skeffa from Ness. But we do suggest that future harvesting be 
consciously planned, and, in view of the recent decline in numbers at 
this colony, we would propose that no more than a thousand young 
should be taken in any one year, until further scientific census work 
justifies an alteration in this number." 

In 1952, however, there were signs of an end to Britain's last 
traditional sea-fowlery (if that is the word). After the war a small 
boat, the Mayflower, with an inboard engine, was substituted for the 
skeffa. It was too heavy to be dragged up the steep rocky landing, 
and was precariously moored near the landing-place, where it had 
to be constantly watched. In 1949 the men got into serious difficulties, 
and in 1952 the Mayflower was lost; the men returning home in a 
larger boat, the Mairi Dhonn from Berneray (Anon, 1952). It would 
be possible to continue the visits in boats of the size of the Mairi 
Dhonn; but for many years now the harbour at Ness, built at great 
expense with public funds, has been silted up, and useless for such 
craft, and the expense of hiring from another parish (Berneray is 
thirty miles away) is probably prohibitive. So, far from being planned, 
future harvesting of the Sula Sgeir gannets is likely to be desultory, or to 
cease altogether after a continuous practice of over four hundred years. 

K. Williamson (1948) gives an excellent account of bird fowling in 
the Faeroe Islands, an important and traditional folk-industry con- 
nected with the bird mountains of the northern and western coasts 
of the islands. In the Faeroes, as in Iceland, fowling has always been 
combined with farming and fishing, and with a culture and civilisation 



100 SEA-BIRDS 

much more advanced than that of St. Kilda. The St. Kildans could 
not read> far less write, and as a result what we know of the size of their 
crops of various species of birds and their eggs comes largely from the 
miscellaneous writings of a few resident ministers and chance visitors, 
from whose accounts the picture has to be fitted together like a jig-saw 
puzzle, of which some pieces have been irrevocably lost. But in the 
Faeroes and Iceland, at least during the nineteenth and twentieth 
centuries, wild-fowl figures have been kept; and though no doubt 
at times and places the inhabitants have given way to various tempta- 
tions, here to exaggerate and there understate their catches, the 
figures published by F. Salomonsen (1935J for the Faeroes and the 
government publication Hagskyrslur Islands for Iceland seem to be 
reasonably accurate. 

In the Faeroes the most important sea-fowl is the puffin, of which 
half a million are killed in the islands in a good year. Some fowlers 
working with the jieyg have killed 900 birds in a day, and 200-300 
per man is quite usual. Williamson, whose important book shows a 
very proper attitude towards food, describes the cooking and eating 
of lundi, and from our own experience in Iceland and elsewhere we 
echo his views as to the excellence of the puffin as food, especially 
when braised in thick gravy and eaten with boiled potatoes sweetened 
with sugar in the northern style, and jam sauce. The Faeroe men 
also kill a large number of guillemots, certainly over 60,000 and 
probably over 100,000 a year, and many razorbills. They also take 
a vast number of guillemots' eggs — some hundreds of thousands — 
though they do not take eggs on a large scale from other species. 
The birds are salted in brine for the winter and the eggs preserved 
in water-glass. The Faeroe men also snare auks on the sea by noose- 
rafts (p. 98) and collect young auks on the sea below their cliffs 
before they grow their primaries and can properly fly. 

Since the psittacosis outbreak in the Faeroes young fulmars have 
been forbidden as an article of food, but before 1936 at least 80,000 
young were taken below the cliffs in early September, and some adults 
were taken as well. There is only one gannetry in the Faeroes, on the 
Holm of Mykines, and here between 400 and 900 young are usually 
taken every year, representing approximately half the output of young 
gannets of the colony. Throughout the literature of fowling it seems to 
be clear that a traditional established colony of sea-birds can suffer 
cropping of up to half its annual output of young at the hands of the 
local fowlers. 



SEA-BIRD NUMBERS AND MAN lOI 

Few Other species of birds are taken at all importantly in the 
Faeroes. Few young shearwaters are eaten, a few young kittiwakes, 
and a few terns' eggs. There is a small eiderdown industry at two places; 
but as at present conducted the exploitation of eiderdown in the Faeroes 
and Iceland is a very 'scientific' custom which involves the taking or 
destruction of no eggs whatsoever, and is therefore not fowling in the 
strict sense. 

In Iceland wild-fowling is still carried on systematically; the 
fowlers use ihefleyg (p. 98) (in the Westmann Islands) but rely more 
on the collection of eggs and the killing of young birds in autumn. 
The eggs most commonly taken are those of both Uria guillemots. 

Psittacosis was discovered in the fulmars of Iceland shortly after 
those of the Faeroes ; and the taking of young fulmars has now been 
forbidden. Previous to the psittacosis outbreak up to nearly 60,000 
fulmars were killed in some years in Iceland, but after 1925 it was never 
more than 50,000, after 1927 not more than 40,000 and after 1933 
not more than 30,000. The last annual total before the psittacosis 
regulations in 1939 was 22,231. Of these by far the most were taken, 
in the Myrdalur area of South Iceland, the Westmann Islands and 
Grimsey. It is rather interesting to note that since the fulmar-fowling 
stopped there has been a decrease in the population of fulmars in 
both Grimsey and the Westmann Islands. In both these places the 
inhabitants have started taking the eggs of fulmars, now that the 
taking of their young has been prohibited. On St. Kilda it was the 
general opinion that while fulmar eggs were extremely palatable their 
taking should be very strictly limited. If a fulmar's egg is taken it 
does not lay a replacement; its breeding cycle is broken, it goes 
prematurely into moult and leaves the colony in a week or two. 
But the taking of a young fulmar from a cliff has no effect upon its 
parents or their breeding cycle; indeed, they are unlikely to be aware 
of it, since most fowlers take fulmars when they are fat on the ledges, 
having already been deserted by their parents, or when they are resting 
on the water after their first glide down to the sea before they can really 
fly. It seems reasonable to suppose that a fulmar whose egg is taken 
might respond to the interference with its breeding cycle sufficiently 
to move its breeding-quarters in a subsequent year; whereas there is 
no possibility of response on the part of an adult fulmar to the taking 
of its well-grown young. 

Apart from fulmars it has been the Iceland custom to take very 
large numbers of puffins, guillemots, razorbills, kittiwakes and gannets. 



102 SEA-BIRDS 

Gannets have been taken on Eldey off the south-west peninsula, one 
of the largest gannetries in the world. (This was declared a sanctuary 
and gannet-taking was forbidden in 1940.) The main annual catch 
of gannets here between 19 10 and 1939 was 3,257, the extremes being 
200 and 4,000; the fowlers never took quite half the total annual 
output of young. On the Westmann Islands gannet-fowling has 
been known for two-and-a-half centuries, and no doubt has gone on 
ever since the islands were colonised in the tenth century. Here 
the total population of nests is now of the order of 5,500. The number 
of young taken has seldom been more than a quarter of the total 
output, most being killed on the flat top of the most inaccessible 
of the breeding cliffs, Siilnasker. In the middle of the 19th century 
it was alleged that as many as 80,333 puffins were taken yearly in the 
Westmann Islands, but during the present century the take has seldom 
exceeded 50,000, and has often been between 20,000 and 30,000. 
At Grimsey often very large numbers of kittiwakes are taken, however, 
more than 10,000 in some years, and nearly as many puffins, but only 
a few hundred guillemots. Very many eggs are taken on Grimsey, 
particularly those of guillemots, of which about 12,000 are collected 
in a normal year, and a number of kittiwakes' eggs also. 

Since the first accurate figures of 1897, there has been a slow decline 
in the number killed for food in Iceland. This should be associated with 
a recent human movement in Iceland from the coastal farms to the 
towns. Certain parts of Iceland's coast, formerly inhabited by farmer- 
fishermen are quite deserted, e.g. the northern part of the north- 
west peninsula. Even in the Westmann Islands, where the fowling 
tradition is very strong, there has been a slight decline. However, as 
long as the Icelanders regard fowling as a manly sport, hallowed by 
generations by tradition, as well as a gainful occupation, fowling will 
continue on its present lines. 

A conclusion from a study of the fowling on St. Kilda, the Faeroes 
and Iceland is that sea-birds were (and are) a source of cheap and good 
food, which can be indefinitely enjoyed, provided a calculated harvest 
be taken from the cliffs which leaves a strong adult population behind. 
Further, this harvest can be large and yet not materially effect the 
size of the colony. Experience over some hundreds of years shows that 
large numbers of eggs* can be taken from those species such as the 
guillemot which readily lay replacements, and that from all others 

*As this book lay in proof the publication began of a most informative summary of 
egg-exploitation, by Hugh B. Cott (1953). 



SEA-BIRD NUMBERS AND MAN I O3 

a crop of fat young can be taken most easily just before the young fly 
or swim away from the colony. Furthermore it seems that it is safe 
to take up to half as many young as there are nests in the colony. 
Of course, this concerns established colonies of great size whose origins 
are lost in the depths of history, and it is possible that a new colony 
just starting up, or a colony struggling for existence at the edge of a 
species' range, cannot stand this kind of human predation. More- 
over, there are certain acts which can be dangerous to the population, 
such as the taking of eggs from species like the fulmar, which do not 
lay replacements. With these reservations, it seems that man can 
exploit a community of sea-birds without killing the geese that lay 
the golden eggs, provided that he restrains his greed and takes less 
than half that which it would be physically possible for him to take. 
He may indeed one day need to consider, more seriously than at 
present, the scientific exploitation of sea-birds for food. The figures 
we have quoted above may then be not without value for fixing the 
annual crop which can be gathered without depleting the colonies. 

* * ♦ 

Man can also, and does, affect the population of sea-birds in ways 
other than by predation — for instance, by building on, or otherwise 
altering, sea-birds' breeding sites and by putting waste matter into 
the sea. Fortunately for sea-birds man has not much use for cliffs, 
except to put lighthouses on, and as objects of admiration and amenity. 
Occasionally man quarries a cliff or builds air raid shelters in it, or 
uses it for target practice. But on the whole his exploitation of a cliffy 
coast is not usually such as to drive away the sea-birds which nest upon 
it. However, not all sea-birds nest on cliffs, and those which nest on 
beaches and marshes, most particularly the terns, have suffered con- 
siderably from shortage of nesting sites, due to man's activities in 
draining marshes for agricultural purposes and in building houses, 
expanding and developing seaside resorts and in the erection of aero- 
dromes and bombing and artillery ranges. However, we must readily 
admit that not all coastal aerodromes and bombing ranges have 
driven the sea-birds away. Sometimes they have driven humans 
away and increased the numbers of the local nesting sea-birds! 

Perhaps of all our British sea-birds the little tern suffers most from 
human building. The chain of seaside cottages and concrete bungalows 
that now strings along the back of every likely beach in England, and 
many in Wales and Scotland, occupies each year yet more of the gravel 
and sandy stretches occupied by the little terns. This is unfortunately 



104 SEA-BIRDS 

true of the many miles of the coast of Norfolk and Suffolk, along 
which, fifty years ago, there was an almost continuous scattered colony 
of little terns; but now they are very few and far between. An interest- 
ing comparison of the vulnerability of a shingle or sandy coast and a 
cliff coast to this advance of man is shown along the coast of Durham 
and Northumberland. Here the industrial towns and villages, with 
their huge human populations, run to the very edge of the cliffs. Yet 
upon the cliffs numbers of sea-birds nest every year and some, like 
the fulmar, are actually increasing. Of course, there is still human 
interference, especially by boys and girls making their first tentative 
experiments in cruelty to animals. But on the whole the cliff birds and 
the cliff- top men live singularly well together. It is gratifying to note 
now the shooting of sea-birds at their colonies "for fun," a sport quite 
widespread in the nineteenth century, has disappeared. 

Man's interference with sea-bird population by what he puts into 
the sea is quite substantial. It can be benign and malevolent. From 
the sea-bird's point of view man's benign contributions consist mainly 
of sewage and fish-offal, and, to a certain extent, whale-offal. Not 
many important main sewers discharge untreated sewage into the sea 
in the British Isles, but, in the eastern United States, Roger Peterson 
writes: "The very best spot for gulls is the sewer outlet at 92nd Street 
in Brooklyn. For several years now the little gull {Lams minutus) a 
tiny European species with smoky-black wing linings, has been seen 
with the buoyant Bonaparte's gulls, snatching titbits that well up in 
the sordid flow. Here in the Narrows, where immigrants get their 
first view of the Statue of Liberty, I have seen both this and another 
European, the black-headed gull. Curiously enough, the only other 
place on our whole Atlantic coast where these two rare Laridae from 
the other side can be depended on is also at a sewer outlet, at Newbury- 
port, Massachusetts. There, for at least ten years, the black-headed 
gull, which looks like a largish Bonaparte's gull with a red bill, has 
been found off the end of the pipe that dumps its waste into the 
Merrimac." 

Fish-offal has been discharged into the sea at fishing ports and 
villages ever since large-scale fishing began, and such ports have always 
had their attendant crowd of gulls — mostly herring-gulls and lesser 
blackbacks and a few great blackbacks. However, in the last few years 
the trawlers have been operating at increasing distances from land, have 
been taking ice with them, and have been gutting and stowing their 
catch at sea. This has meant that at every trawl there has been a great 



SEA-BIRD NUMBERS AND MAN IO5 

discharge of unwanted ofFal, and of unwanted species of fish, squids 
and other molluscs. Every deep-sea trawler starts from port with a 
retinue of gulls, some of which may follow for about fifty miles or more 
to sea; a few occasionally farther. After that, in the deep ocean, ful- 
mars are the principal scavengers in the wake of trawlers which work 
the north-western and arctic fishing banks. Every time the haul 
comes up in the coastal belt the gulls resting on the sea gather more 
closely round the ship, and at every gutting time they scream and 
fight for offal. The rise of the fishing industry has unquestionably 
aflfected the population of the gulls round Britain, and a similar state 
of affairs has been reported by A. O. Gross (1951) from the northern 
United States sea-board. In 1900, for instance, the great blackback 
was practically extinct as a breeding species in England and Wales. 
In the years round 1930, however, Harrisson and Hurrell (1933) 
estimated that between 600 and 800 pairs nested in Scilly, about 
180 in Pembrokeshire, over 60 in Cornwall, 50 on Lundy, about 
45 in the rest of Devon and about 60 in the rest of England and Wales. 
These figures are probably trebled today; and a parallel increase 
has taken place also in Ireland and west and north Scotland, where 
the species has always had a large population. On the United States 
sea-board before 191 6 the great blackback nested nowhere at all. 
Its farthest breeding place was on the Canadian border of the Bay 
of Fundy, but in 1906 a pair bred in Maine and in 1928 three pairs 
certainly did so. By 1931 there were at least ten stations in Maine 
and one in Massachusetts, and since then it has spread south as far 
as New York. The U.S. population consisted of some 1,250 pairs in 
1944. There are 700 pairs in one bay in Maine alone. 

But of all the birds which have been affected by man's dumping 
of this kind of food into the sea the fulmar has responded most markedly. 
Both of us independently came to the conclusion that the astonishing 
spread of the fulmar — the biggest revolution in the numbers of any 
widely-spread sea-bird (or any bird?) — is primarily connected with 
modern trawling and probably with its predecessor, North Atlantic 
whaling. This spread is described in detail in Fisher's The Fulmar 
(1952), and we do not wish to recapitulate the evidence here. Suffice 
it to say that the spread has been going on now for 200 years, having 
been first started in south Iceland in the middle of the eighteenth- 
century, that it has completely changed the bird's distribution in 
Iceland, the Faeroes and Britain, and that it still continues, no less 
than thirty colonies or potential colonies being founded annually 



15° 12* n" \0 



MILES 




VVTLON'O o° 



V^ LONO. 



Fig. 1 8 
Sketch map of Britain showing fuknar colonies known by 1949. Breeding colonies 
black; colonies where fulmars prospecting, but not yet proved to breed, crossed 
circles. Dates of first breeding at important colonies indicated. Grosses represent 
places where fulmars have been seen in the breeding season but where they have 
not yet been proved to be "interested" in establishing a breeding colony (from 

Fisher, igss) 



SEA-BIRD NUMBERS AND MAN IO7 

on the British coast alone. Fig. i8, (opposite) shows the spread of the 
fulmar in Britain: before 1878 it was known to nest only on St. Kilda. 

Fulmars congregate round trawlers in enormous numbers, up to 
more than five thousand at one time. Probably every trawler operating 
within a few hundred miles of a fulmar colony is visited. Almost 
invariably, the fulmars outnumber any other kind of bird present 
at hauhng or gutting times. They greedily devour the loose dead 
fish and bits of fish that come up with the cod end, as well as 
the guts that are thrown overboard — especially the livers, which are 
grabbed first. In many parts of the North Atlantic from May to 
October they are often accompanied by a minority of Tristan great 
shearwaters and sooty shearwaters. 

Man has one entirely malignant effect on sea-bird populations. 
He casts crude or waste oil into the sea. This oil of course floats on 
the surface of the water, and a relatively small amount of oil can 
form a thin film covering some square miles. The volatile oils evaporate, 
leaving an asphaltic residue which is sticky. When sea-birds swim 
or dive through this, they quickly get their feathers matted. 
This reduces the surface tension of the plumage, and the subcutaneous 
air spaces, to which the birds owe most of their insulation and much of 
their buoyancy, are filled with oily water. In cold weather the birds 
rapidly; lose heat, which they are unable to replace by hunting and 
feeding. Most of them die. The oil menace particularly aff'ects the 
surface swimming guillemots and razorbills, which do most of their 
feeding over the Continental Shelf, and often close to shipping routes. 
Puffins and gannets also suffer, but not quite to the same extent. 
For many years this question of oihng has exercised the bird protection 
societies, and there have been many international meetings and dis- 
cussions about it. In 1926, for instance, the United States government 
was host to an international conference in Washington, but at this 
there was a division of opinion as to what should be done, and all 
that resulted was a recommendation that oil should not be discharged 
within fifty miles from land. Some governments, it is true, passed 
this recommendation to their shipping companies and navies, and, 
in some cases, the recommendation was even acted upon, but there 
was no noticeable diminution in the number of cases of oiling, and 
during the late thirties and the forties, particularly during the war, 
oihng has been worse than it has ever been, at least round the coast 
of Britain. There is no question but that sometimes the waste of sea-bird 
life through oil pollution is substantial. It is also, of course, a common- 



I08 SEA-BIRDS 

place that the end to which the unfortunate birds come is a particularly 
sticky one and horrifying and nauseating to all humane people. At 
all recent ornithological congresses, and nearly every international 
meeting for bird preservation, the existence of this problem has been 
discussed, debated, and hundreds of recommendations have been 
made by scores of bodies to scores of governments, many of whom have 
given assurances and promises. However, these words have not saved 
the sea-birds, who still continue to die in large numbers round our 
shores. In Britain we have the Oil in Navigable Waters Act of 1921, 
which has been observed as carefully as possible by all shipping 
plying to British ports. However, there have been recent occasions 
upon which it is obvious that this Act has been grossly ignored, and 
during the war a number of tankers were torpedoed and wrecked, 
with consequent effects upon the auks. Unfortunately one big discharge 
of oil will pollute the sea for a very large area and for a very long time. 
It is rather interesting to note that the auks, in particular the 
guillemot and razorbill, are among the few common British sea-birds 
in which a decrease has occurred during the present century. This 
decrease must not be exaggerated, and it has not been noticeable in 
all parts of Britain. One of these noticeable decreases is on Ailsa Craig 
in the Clyde, which lies on a main shipping route. J. A. Gibson (1951) 
thinks that the present population of not more than 5,000 pairs of 
guillemots is about one-tenth of what it was forty years ago. In 
1937 one of us found 61 auks, most of which were guillemots, and 22 
gannets on Ailsa's two-and-a-half miles of coast-line, incapable of 
survival, so thickly were they 'oiled'. But the experience of Gibson in 
1948 was far more harrowing; on 23 August, along but half a mile 
of beach, he counted eight hundred and fifty badly oiled guillemots 
ashore and many hundreds floating a little way out at sea. There were 
hundreds more round the rest of the coastline of the island — all due 
to die. This was nearly a quarter of the breeding population of the 
Craig. He illustrates the general decline in the guillemot's fortunes 
on Ailsa Craig by the following interesting figures from parts of the 
bird-cliffs known as Ashydoo (A) and the Bed o' Grass (B) : 

A B Total 

Average yearly 'bag' of eggs in the 

years 1905-10 1,080 1,320 2,400 

Number of apparently incubating 

pairs in 1950 240 c.2^0 r.500 

Gibson thinks that the present population (5,381 pairs in 1950) 



SEA-BIRD NUMBERS AND MAN IO9 

is about a tenth of what it was forty years ago. This would seem to 
fit the figures from Ashydoo and the Bed o' Grass if, as seems reason- 
able, the eggers took about half the eggs. 

Unfortunately precise figures of the number of auks killed by oiling 
round the coast of Britain have never been collected. The pronounced 
decrease of guillemots at Skomer in Pembrokeshire may be due to the 
present extensive oil-pollution of the Bristol Channel. The Royal 
Society for the Protection of Birds, just as this chapter was being written, 
began to collect scientific information on a wide scale, and it is hoped 
to have some concrete information as to the real extent of the menace 
in a few years. The remedy — oil-separators on ship and at every 
port used by oil-carrying ships — is obvious, and well-known, but 
waits international agreement. 



CHAPTER 4 

WHAT CONTROLS 
THE NUMBERS OF SEA-BIRDS? 



ALTHOUGH MAN is SO much the most important predator of sea- 
birds, except in very inaccessible places such as the Antarctic 
Continent and some of the Subantarctic islands, the existence of other 
animal predators should not be overlooked. The number and import- 
ance of these is not great, and the effect of these predators upon the 
population of their prey is small; but, on the other hand, the effect 
of the numbers of the prey upon the numbers of the predators may 
be marked. It is abnormal for a predator to take a crop from its 
prey which is more than that prey can easily spare. At every important 
sea-bird station there is normally a small, but often varied community 
of animals which are predators on the individual members of the 
main community or their eggs and young. At a typical British island 
bird rock the predators are all birds. Ravens snap up young that fall 
from the cliffs or adults which meet with flying accidents (below the 
cHffs of Ailsa Craig we have seen a raven eviscerating a still living 
gannet that had been starving for some days with a broken wing). 
Hooded and carrion-crows nest, like the ravens, on the cliffs of many 
sea-bird stations, and poach eggs and pick up what they can get. 
Peregrine falcons also nest on the cliffs and prey upon the inmates. 
At a peregrine eyrie on Skomer, in 1946, we found two eyasses sitting 
among the remains of eleven Manx shearwaters and two puffins. 
Even the short-eared owl may occasionally nest on British islands 
and prey upon the sea-birds. One of the pair nesting on Skomer 
used to operate to the neighbouring bird island of Skokholm, where a 
pellet was found containing the remains of a storm-petrel; and on 
Skomer the newly-arrived little owls also have persecuted the storm- 
petrels. But the most important animal predators of sea-birds are 
other sea-birds. In Shetland the arctic and great skuas of Noss chase 



WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? Ill 

terns, kittiwakes and even gannets, to force them to vomit fish, which 
is then seized by the pursuer. Seldom do these parasites (a truer 
word for these particular birds than predators) actually kill their prey. 
However the bonxies, or great skuas, frequently hunt and drown 
the local kittiwakes, as R. Perry (1948) has observed, dropping on 
top of them and forcing them down on to the water, often working 
in couples. The great skuas of Noss and Foula indulge in predation of 
kittiwakes, as well as guillemots, until the gannets are feeding young, 
and do not take to parasitism of their main host until then. They 
also chase great blackbacks and herring-gulls, and make them vomit. 
The great skuas, like the great blackbacks, watch the cliffs for the 
young guillemots on their first flights to the sea. Both also take fledge- 
ling kittiwakes and fledgeling herring-gulls. The arctic skuas of Noss 
get most of their prey by harrying kittiwakes, guillemots and terns 
over the sea a couple of miles from the island. 

The herring-gull is an important predator of other sea-birds, 
although it has not the aggressive qualities of the great blackback. 
It is particularly good at robbing gannets of their egg, taking quick 
advantage of any unusual disturbance in a gannetry, such as the 
arrival of human beings. Fulmars are much more difficult to dislodge 
from their eggs than are gannets, but once human investigators have 
put the fulmars off, the ever- watchful herring-gulls snap the eggs up. 
The herring-gull is probably the worst egg-robber of the bird-cliffs, 
and it will take nestlings of any species of gull (including its own), 
of terns and of the auks. 

The lesser blackback, though not quite so aggressive as the herring- 
gull, has been known to kill adult puffins and Manx shearwaters, and 
the young of many cliff-breeding birds. The great blackback eats 
everything so far mentioned. It will smash eggs by taking them up 
to a height and then dropping them. In general, however, most of 
of these gulls, predatory though they are, seek their living away from 
the colony. Often very large colonies of herring-gulls, lesser blackbacks 
and great blackbacks — sometimes even all three — are situated at the 
top of a teeming bird-cliff. If all the gulls were to rely only on what 
they were to get from the bird-cliff the community might collapse. 
They should be properly described as opportunist predators, who 
earn their main living elsewhere, — nowadays, as we have already 
pointed out (p. 104) — very largely as parasites upon the fishing industry 
of the coast. 

In the Arctic the glaucous gull to a large extent takes the place 



112 SEA-BIRDS 

of the great blackback, and in Greenland the Iceland gull the place 
of the herring-gull. Their place in nature seems to be exactly the same, 
and their behaviour and function as a member of the cliff-community 

is identical. 

Other birds not yet mentioned which prey upon sea-birds of the 
North Atlantic community are the bald, white-tailed, and even golden 
eagles; and sometimes the snowy owl and the eagle-owl. and the gyr- 
falcon. The long-tailed skua is not a predator of breeding sea-bird 
communities, but pursues terns and kittiwakes at sea to a certain 
extent in the off-season. The same is largely true of the pomarine 
skua, though this does occasionally take young sea-birds on the 
breeding-ground. Of course there are many other bird predators 
which have occasionally picked up sea-birds in the course of their 
hunting operations. Examples are: the merhn (which has taken a little 
tern), common buzzard (which has taken a guillemot and often 
young Manx shearwaters), marsh-harrier (a young black-headed gull) 
goshawk (a common tern and an arctic (BriJnnich's) guillemot) 
and the sparrow-hawk (a Leach's petrel and little tern). 

Of the mammal predators of the North Atlantic sea-birds quite 
a formidable list could be compiled if we were to include every animal 
that had ever been seen to eat a sea-bird. The list would certainly admit 
the polar bear, the arctic wolf, the arctic fox, the red fox of the Old 
World and the red fox of the New World, the otter, the stoat, the 
killer- whale, the harp-seal of Newfoundland, and possibly the "black" 
rat {Rattus rattus), as well as the abundant brown rat {R, norvegicus). 
It is a commonplace that in Spitsbergen and Greenland, and no 
doubt in other parts of the Arctic, the presence of arctic foxes forces 
the sea-birds to occupy the more inaccessible ledges of the cliffs; 
and they are quite important predators of the more vulnerable occu- 
piers of the edges of the colonies. In Britain there are foxes on very 
few islands, but the sea-bird stations on the mainland, notably that 
at 016 Mor in north Sutherland near Cape Wrath, are harried by foxes. 
Indeed, the foxes of C16 Mor have their cairn at the top of the most 
important bird cliff. 

Undoubtedly the only really serious mammal predator of the 
North Atlantic sea-birds is the rat, and we believe it is the only sea- 
bird predator which can really be said to have made a significant 
difference to the status of certain species. It is an introduced species, 
not yet in a balanced ecological relationship with its prey where it 
comes into contact with certain burrowing sea-birds. To give an 




Plate XIa. Ringing a Leach's 
Petrel. North Rona 

(Flashlight I'hoto by Robert Atkinson) 



b. The Madeiran Petrel has a 
slightly forked tail and a con- 
spicuously white rimip 

[R. .\f. Locklev) 





R. M. Lockley 

Plate Xlla. Berlengas Islands, Portugal. A lighthousekeeper holds firmly the powerful 
North Atlantic Shearwater, Puffimis kuhlii, which breeds there, and is freely taken for food 



b. Flashlight photograph of Manx Shearwater, Skokholm, Pembrokeshire 



Robfrl Atkinson 





WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? II3 

example, about a hundred years ago the puffin was by far the most 
numerous bird on Ailsa Craig in the Clyde. Its numbers were described 
by many observers up to about 1900 as phenomenal. There were the 
usual expressions about their darkening the sky. Gibson states (though 
on what grounds we do not know) that there were probably over a 
quarter of a million puffins in the i86o's. Unfortunately in 1889, 
rats got ashore from a wreck. Their effect was not immediate but the 
decrease of the puffins became noticeable between 1900 and 1910, 
and serious by 1927 — when indeed only a few were to be found. By 
the 1930's the puffin was practically extinct, and on yearly visits to 
the island between 1936 and 1942 one of us never saw more than a 
hundred birds. By 1947 Gibson estimated that there were only thirty 
birds on the whole island. He puts the decrease down to the combined 
effects of rats, oil and gulls, though there seems to be no real evidence 
that any but the first factor has operated importantly. Certainly 
puffins in the Clyde area do not seem to get oiled in the same way as 
guillemots and razorbills, and do not appear to have been involved 
in the appalling oiling disasters of 1937 and 1948. Later Gibson 
records a considerable recovery for in 1950 he found 246 birds 
occupying twelve different parts of the island; only one part of the 
island was occupied in 1947. Rats continue to inhabit the Craig. 
Equally disastrous histories can be related for other islands, though 
without so many definite facts. In about 1689 a swarm of rats, which 
must have been black rats, infested North Rona, which was then 
inhabited by a small human community. The rats are said to have 
eaten up all the corn on the island and caused the death of the entire 
human population (nothing is said about sea-birds). 

On Lundy (a Norse word meaning Puffin Island) puffins once 
bred in "incredible numbers" — at least 100,000 pairs. Rats on this 
island have reduced the puffins, it is beheved, to their present numbers 
of 400 pairs in 1952. On one of the Shiant islands in the Minch, there 
is a population of brown rats which, at the time of our visit, invaded 
the house and kept the ornithologists awake. The big puffin colony 
in the talus slopes of the Shiants still survives, and is very large, though 
its size is certainly not up to some of the descriptions of it in the last 
century. How important the decrease has been, and whether it is 
due altogether to the rats it is difficult to measure. There are fortunately 
no rats at some of the finest sea-bird stations in Britain, such as Handa, 
St. Kilda, Sula Sgeir, North Rona and Skomer. There are rats on 
Foula, though it is doubtful whether they can get anywhere near the 



114 SEA-BIRDS 

largest puffinry, which is on a broad ledge exactly half-way down the 
incredible cliff of the Kame. 

Occasionally (and certainly not very importantly) fish have been 
known to prey upon sea-birds. W. E. Glegg (1945, 1947), who has 
compiled records of aquatic animals preying upon birds, lists the 
angler-fish as having taken scoter, merganser, cormorant, Manx 
shearwater, great northern diver, gulls (including the herring-gull), 
razorbill and guillemots. He also lists the cod as having taken cormor- 
ant, Briinnich's guillemot and black guillemot; angel-fish and pike 
as having taken cormorant; unknown fish as having taken the white- 
winged black tern, and what were probably fish as having taken the 
Sandwich tern and the African grey-headed gull. 

The ectoparasites of sea-birds are many. They include several 
highly specialised mites, many mallophaga or biting-lice, ticks and some 
fleas. There is no evidence whatsoever that any of them significantly 
control the numbers of their host, nor, indeed, any evidence that any 
of them carry diseases.* 

Very little is known about the endoparasites of sea-birds; they 
have many species of cestodes, nematodes and trematodes, and some 
protozoa. Extremely little is known about the bacterial and virus 
parasites of birds, though it appears that of all the internal parasites 
these are the only ones likely to affect natural populations. Recently 
considerable attention has been drawn to the virus diseases of sea- 
birds by J. A. R. Miles, who has identified a virus epizootic of the 
Manx shearwater which he calls puffinosis (Miles and Stoker, 1948). 
This disease kills young Manx shearwaters in the crowded Pembrokeshire 
colonies; the colony on Skokholm, judging from ringing records, 
is usually between 10,000 and 15,000 birds and that on Skomer double. 
In some years "many hundreds" of young Manx shearwaters are found 
dead, but there is no evidence that the disease materially affects the 
population. (Surrey-Dane, Miles and Stoker, 1953). 

The most important sea-bird disease so far identified is undoubtedly 
psittacosis (a form of ornithosis) which, in the early 1930's, spread 
through the vast population of the fulmars nesting in the Faeroes and 
Iceland. The arguments of R. K. Rasmussen, who first identified the 
disease, and J. A. R. Miles, who has subsequently studied the problem 
(Miles and Shrivastav, 1951), are summarised in Fisher's The Fulmar 

*In 1949 Lockley found hundreds of fledgeling puffins dying of excessive blood- 
sucking by the common red mite [Dermanyssus gallinae) on the islet of Burhou, Channel 
Islands. 



WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? II5 

(1952), and all that it is necessary to say here is that there is a real 
possibility that the fulmars may have contracted the psittacosis from 
a dead parrot or parrots. However, while this disease has killed quite 
a number of human beings who have split or eaten infected young 
fulmars in September, there is no evidence that it has made any serious 
difference to the actual fulmar population. It is not even proved that 
there is a large mortality among the young fulmars, some at least 
of which appeared to recover. A strain of ornithosis of another kind 
has been found in herring-gull, lesser blackback, laughing gull, 
royal tern and little tern. 

From this short survey of the possibilities we find that man most 
importantly controls the number of sea-birds; but that the only 
other organisms in a long list of predators and parasites that may also 
do so in any serious way or to any significant extent are (under special 
circumstances) rats and possibly a virus or viruses. But it is quite 
certain that none of the other animals which live on or in sea-birds 
can possibly be responsible for the changes in sea-bird populations 
which are clearly going on all the time. 

There remain three other factors to investigate; for it is possible 
that the numbers of sea-birds may be limited by the availability of 
nest sites, by climate and weather, and by the availability of food. 

Before we proceed to a further discussion of these points we must 
remind the reader of an important principle, and for the first time, 
state another important principle. The principle already stated (p. 37) 
is that so carefully established by E. Mayr (1942) and D. Lack (1944) — 
that in the course of evolution new species of birds originate when 
forms of the parent species differentiate in geographical isolation and 
subsequently meet in the same area. The second principle, which we 
have not so far encountered, was stated by the Russian zoologist 
G. F. Gause in 1934. It is that two closely related species with identical 
ecology cannot live together in the same place. Generally speaking 
throughout the world of animal ecology these two principles have 
been accepted, though not without some reservations by critical 
workers such as W. H. Thorpe (1945). 

As Lack states, when two such differentiating forms of the same 
parent-species meet, they will tend to compete ecologically but will 
eventually reach one of four more stable positions. First, one species 
may eliminate the other completely (this is likely to happen if they 
still have the same fundamental ecology). Secondly, the two may 
withdraw once more to occupy separate but contiguous geographical 



Il6 SEA-BIRDS 

regions. Thirdly, they may occupy different habitats in the same 
region. And, fourthly, they may live in the same habitat and region 
but eat mainly different foods. Lack points out that the last position 
is often reached when the two species differ markedly in size. His 
analysis was confined to passerine birds, for which habitat-distinc- 
tions are much more clearly marked than they are for sea-birds; 
and we know of no closely-related species of sea-birds which do, in fact, 
clearly occupy different habitats in the same region in this way. 
The occupation of different kinds of nest-site on the breeding-cliffs 
is very closely marked among sea-birds. Every species appears to 
have its special niche. Although there remains apparent competition 
for nest-sites at least between certain species at most sea-bird stations, 
it is a rule that the denser the population of the station, and the greater 
the number of species occupying it, the keener and more definite 
does this nest-site selection become. Among the petrels this may result 
in a division of the year into separate breeding seasons between species 
using the same nesting burrow (Lockley, 1952). It would be interesting 
to collect their parasites. 

A similar state of affairs appears to exist with the food of sea-birds. 
Indeed, the situation gives the impression that there is a kind of non- 
intervention agreement among the sea-birds by which each has chosen 
its own particular kind of nest-place and its own particular kind of 
food so as to avoid competition with the other species. The question is 
how this state of affairs has come about in the course of evolution. 

A full answer seems impossible to give over the question of the 
differential nest-site selection, at least in the present state of theory, 
though a very great many facts have been collected and are still being 
collected about the nest-site shortage on the breeding-grounds of 
sea-birds. 

To the question of the differential feeding habits, a clear answer 
is suggested by the work of Mayr and Lack. In general terms it is that, 
unless two forms derived from the same parent-species which meet 
together on the same area are already at least partly differentiated 
as regards their feeding-habits, one will ehminate the other from the 
area. If this is true — and there is every reason from the evidence to 
believe that it is — then the origin of a species will depend on its pos- 
sesion of a special pattern of food-preferences. We will find that the 
population of the species will depend also, in normal circumstances, 
on the natural supply of the food of that pattern. Indeed, we will dis- 
cover that only under the interference of quite exceptional agents, 







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WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? II7 

such as man, or exotic species of animals, introduced either consciously 
or unconsciously by man, or sudden cataclysms of climate, will the 
fundamental numbers of a species be determined by any other factor 
than food-supply. 

Of course, the food-supply often depends directly on other factors 
such as the weather; and upon the available food supplies the gradual 
processes of history and evolutionary change are also working. But, 
owing to the uniqueness of every species' food-pattern, direct competi- 
tion with other related species may not be a normal factor in population 
control! When such direct competition is found, as it is occasionally 
under peculiar circumstances, it is perhaps the exception that proves 
the rule. 

The first case that we can discover in the literature which precisely 
states the existence of specific food-patterns among closely related 
sea-birds is an analysis by the Russian zoologist A. N. Formosov, 
quoted by the pioneer Gause in his Struggle for Existence. In 1923 
Formosov examined a mixed colony of terns consisting of many 
hundreds of each of four species on an island on the west side of the 
Crimean peninsula. Slightly paraphrasing Formosov's notes, he writes 
that, "the nests of the terns are situated close to one another and the 
colony presents a whole system. The entire population of the colony 
belongs to four species, the Sandwich tern, the common tern, the 
gull-billed tern and the little tern, and together they chase away 
predators, e.g. hen-harriers, from the colony. However, as regards the 
procuring of food there is a sharp difference between them, for every 
species pursues a definite kind of animal in perfectly definite conditions. 
Thus the Sandwich terns flies out into the open sea to hunt certain 
species of fish, the gull-billed tern feeds exclusively on land and can 
be met in the steppes at a great distance from the sea shore, where it 
destroys locusts and lizards. The common tern and the little tern catch 
fish not far away from the shore, sighting them while flying and then 
falling upon the water and plunging to a small depth. But the light 
little tern seized the fish in shallow swampy places, whereas the common 
tern hunts somewhat farther from the shore. In this manner these 
four similar species of tern living side-by-side upon a single small island 
differ sharply in all their methods of feeding and procuring food." 

However, it is uncommon for all these four species to nest together 
in the same colony. Usually there is also a fairly marked difference 
in their selection of nest-sites. For instance, the little tern is more 
inclined to nest on shingle than the others and the gull-billed tern 



Il8 SEA-BIRDS 

more near marshy places, though it will nest on sand. At most British 
colonies where there are common and Sandwich terns together the 
two species usually nest apart, though it is difficult to detect any 
particular preference in the type of ground favoured. 

So far among closely related sea-birds there have been few studies 
of difference in feeding-habits, though much is now known in the 
North Atlantic about the difference in their nesting-site preferences. 
Such pairs of closely related species as have been carefully analysed 
show that the principle of Gause is in general correct; they do not 
have the same ecology and there are marked differences in their food- 
patterns. D. Lack (1945) points out that if one was to rely on the 
information given in general works on British birds and by W. E. 
Collinge (1924-27) one might come to the conclusion that the cormorant 
and the shag eat mainly the same type of food. Fortunately the econ- 
omic issues involved (because these species might be thought to 
compete with fishermen) led to G. A. Steven (1933) carefully investigat- 
ing the food of these two species round the shores of Cornwall. Steven's 
investigations made it abundantly clear that the difference was very 
great. For instance the shag ate more sand-eels than any other prey; 
the cormorant none. The cormorant ate more fiat-fish than any other 
prey; the shag a very small amount. The shag ate fairly large numbers 
of sprats and sardines and other small fish, whereas the cormorant 
appeared only to swallow them by chance. The cormorant, on the 
other hand, ate great quantities of prawns and shrimps, which the 
shag appears to swallow only by chance. In general the cormorant 
fed primarily on animals which live on or close to the bottom of the 
sea, while the shag fed mainly on free-swimming forms. 

Later Lumsden and Haddow (1946) examined the food of the shag 
in the Clyde area and came to similar conclusions about its preferences 
for sand-eels, small clupeoids and sprats, sardines etc., though the 
Clyde birds preferred sand-eels to clupeoids. 

A rather wider investigation was made by C. H. Hartley and 
Fisher in Spitsbergen in 1933. In a fjord in the centre of Spitsbergen 
they studied the food of the many sea-birds which were feeding in a 
special food-rich zone at the face of a glacier running into the sea. 
In spite of the super-abundance of one particular crustacean, Thysa- 
noessa inermis, which all but one of the ten sea-birds present ate in 
large quantities, the food-pattern of each proved to be distinct. Thus, 
besides Thysanoessa the kittiwake seemed particularly fond of a crusta- 
acean Euthemisto libellula; the fulmar of offal; the arctic tern of a 



WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? Iig 

shallow-water crustacean Adysis oculata; the glaucous and ivory-gulls 
of offal ; the eider of a crustacean Gammarus locusta and lamellibranch 
molluscs; BriJnnich's guillemot of a prawn Spirontocharis gaimardii; 
the black guillemot oi^ Mysis and gasteropod molluscs; besides various 
other shallow- water creatures including butter-fish; and the puffin 
of fish. Unfortunately we did not sample enough little auks to be 
quite clear as to their preference, though it appeared to be entirely 
crustaceans. Of the offal-eaters the fulmar ate a wide range of other 
organisms besides Thysanoessa; the glaucous gull ate a few Euthemisto; 
the ivory-gull ate nothing but Thysanoessa and offal; but every one of 
the species, as far as could be detected, had a different food-spectrum 
in spite of the abundance of Thysanoessa. 

It is clear that under conditions of super-abundance, species 
that would otherwise compete can, at least temporarily, share the same 
main food. To give another example: in north-central Iceland is 
a large shallow lake, Myvatn, of quite exceptional fertility, in which 
the hatch of insects in June is one of the marvels of nature. Myvatn 
is probably the finest duck lake in the world: it supports a population 
of several tens of thousands of ducks belonging to about ten established 
species (fourteen have bred by or near the lake in the present century). 
Almost every indication of differences in nest-site choice and food- 
spectra between the ducks of Myvatn has disappeared, and in places 
their nests are placed almost in rows, apparently indiscriminately, 
in the grass and willow cover at the edge of the lake. All feed apparently 
on the same supply of chironomid insects. Often they appear to make 
mistakes and lay eggs in each other's nests. Again: it is a common 
sight in a large colony of auks to find puffins, guillemots, razorbills 
feeding together on shoals of sand-eels and small fry (perhaps joined 
by other sea-birds such as gulls and shearwaters) which swarm inshore 
during June, July and August in British waters. But it remains prob- 
able that even under the special conditions in both examples quoted, 
some differences in food-spectra persist, as well as the normal differ- 
ences in feeding actions. 

There is, in the wide an scattered a iterature, already a good 
deal of information of a qualitative, if nOt of a quantitative kind, 
which tells us about differences in the food-patterns of closely related 
sea-birds; and certainly serves to indicate that in all cases those patterns 
are different except perhaps under the rare and exceptional conditions 
of food super-abundance. It is true, however, that no deliberate and 
quantitative research has so far been done on certain obvious pairs 



120 SEA-BIRDS 

actually in the zones where the two species overlap. Thus no serious 
work has been done on the food of the arctic and common terns in 
the fairly wide zones of overlap in both New and Old Worlds, nor 
is there any detailed investigation of the different foods of the different 
divers or Leach's and storm-petrels, or of the different tropic-birds and 
frigate-birds, or, rather surprisingly, of the herring- and lesser black- 
backed gulls as a straight comparison, or of BrtJnnich's guillemot 
and the common guillemot. 

In the tropics the three boobies — the blue-faced booby, the brown 
booby and the red-footed booby — overlap considerably, sharing many 
of the same breeding-places and feeding-grounds, e.g. round Ascension 
Island. They differ in ecology quite markedly. Thus, the blue-faced 
booby nests on fiat ground, making only a scrape, the brown booby 
on the ground but usually on eminences and then with considerable 
nest-material (it may also perch but not nest on trees), while the red- 
footed booby nests exclusively on trees and bushes and is limited 
to breeding on islands which can provide them. While their food 
habits have not been closely compared it seems clear, from the account 
of Murphy (1936) that they are different; the blue-faced booby appears 
to be primarily an eater of small squids, the brown booby an eater of 
flying-fish and many other species of surface-fish, the red-footed booby 
primarily a diurnal eater of flying-fish but also a nocturnal feeder on 
squids. 

If we study the skuas, gulls and terns we find perhaps the most 
complicated food-systems and habitat-selection of any of the sea-birds, 
and it will be a long time before research has sorted out the real 
differences which undoubtedly exist between the different species and 
forms. Two similar species overlap geographically very often, and there 
are several cases where three similar species overlap, and one case 
where four do so. In the southern United States, for instance, the com- 
mon tern overlaps with the closely allied Forster's tern, and in northern 
North America with the closely allied arctic tern. In many parts of 
the arctic all three species of the smaller skuas breed in the same general 
geographical area. In Greenland the glaucous gull overlaps with 
the very similar Iceland gull or Greenland herring-gull, and with 
the more closely related, but not so similar, greater blackback. In 
Iceland the great blackback and glaucous gull overlap, and recently 
they have been joined in the same general geographical area by the 
herring-gull and lesser blackback, though so far there is no record of 
all four species nesting together on the same cliff. 



WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? 121 

Wherever the ecology of these species has been intensively studied, 
real differences in food patterns are apparent. Thus, of the three 
skuas, the pomarine skua remains addicted throughout the breeding- 
season primarily to the "orthodox" skua life of parasitising and robbing 
other sea-birds for their food. The arctic skua has the most generalised 
feeding habits: in certain parts of its range where there are no rodents 
it lives rather like the pomarine skua, provided the pomarine does not 
overlap with it: in areas where there are voles, mice or lemmings, 
it eats quantities of these in the breeding season. The long-tailed skua, 
while it does parasitise sea-birds to a slight extent in its winter range, 
seems to have become primarily a rodent-feeder and its breeding range 
is practically limited to those parts of the world in which rodent food 
is abundant. 

Many overlaps occur in the gulls of Britain and north-western 
Europe where, at the two ends of a long chain of forms which embraces 
the whole of the northern hemisphere (see Fig. 4^, p. 41) the herring- 
gull and lesser blackback share a breeding-range, and, at least through 
most of the year, a feeding-range. What their original food spectra 
were and that of the other close relation which overlaps with them — 
the great blackback — might be discovered by the study of populations 
which have no connection with fishing-ports. Where such independent 
populations exist, if they do, they have certainly not yet been critically 
compared. In north-western North America the short-billed gull, 
which is an eastward extension across the Bering Straits of the common- 
gull or mew-gull, overlaps with the ring-billed gull. The two birds 
are fortunately sufficiently different in the zone of overlap to behave 
as distinct species. As far as we know there has been no precise investi- 
gation of their feeding habits. The information collected by Bent 
(1921) gives us no real clue as the observations were not made in the 
area of overlap. Both appear to have similar nesting habits, both 
breeding on the ground and in trees. (Map, fig. 5, p. 44). 

From Salomonsen's account of the glaucous and Iceland gull in 
Greenland it is evident that there is a fairly clear difference in their 
nest-site selection. The nests of the Iceland gull are placed on narrower 
ledges, and at the mixed colonies they, "keep at a respectful distance 
below the glaucous gulls . . . being separated from them by a belt 
of no-man's-land." The Iceland gull is a fish — and crustacean-eater 
primarily, and also a scavenger, but it does not take any living bird, 
and in Salomonsen's opinion the food-competition between the two 
species is "slight or non-existent." The glaucous gull is a predator 



122 SEA-BIRDS 

of Other birds, notably the little auk, at all of whose breeding-places 
in Greenland there is a dependent community of glaucous gulls. It 
also takes fish and many crustaceans, thus overlapping with the Iceland 
gull in the consumption of these foods which often, however, exist in 
superabundance, notably at the faces of glaciers and near icebergs. 
Unfortunately no stomach contents of the great blackback have been 
investigated in Greenland, so it is not possible to make a comparison 
between this species and the glaucous gull. It is certainly a predator 
as well as a scavenger in Greenland, as it is in other countries. 

As far as we know nobody has ever investigated and compared 
the food of Briinnich's and the common guillemots in the areas where 
they overlap. No doubt there is a difference in their spectra even if it 
is only a subtle one, as with their nest-site selection. For these two 
very closely-related species breed on the same cliffs and the most 
constant detectable difference in their habits is that on the whole 
the Briinnich's guillemots tend to incubate on more sheltered ledges 
and in cracks, thus taking up the niche occupied by the razorbill, 
whose distributional range it touches but does not overlap. Its bill 
is even like that of the razorbill (at least in winter form) and it may 
occupy the same food niche: the razorbill eats rather less fish and more 
crustaceans than the common guillemot. The rather scanty studies 
of the food of the common guillemot indicate that more than half 
of it is fish, about a third crustaceans and the rest marine molluscs. It 
seems likely, from the studies in the arctic regions, that Briinnich's 
guillemot eats a greater proportion of crustaceans, particularly plank- 
tonic ones like Thysanoessa. 

To sum up, then, the evidence shows that Gause was right, and 
that closely related species living in the same area do not show an 
identical ecology. It seems logical, from this, to conclude that every 
species of sea-bird (and, for that matter, every bird) possesses a charac- 
teristic food-supply and that while this — its "food-spectrum" — may 
change in the course of history (as it has done, for instance, with the 
fulmar) in the long run the numbers of sea-birds depend on their 
food-factors rather than on other factors in the environment, however 
important. Probably the populations do not depend on the supply 
of nest-sites unless this is directly threatened by man; we must record, 
however, that in the North Atlantic, because of man, many safe 
breeding-places were not so in the recent past and some species 
(e.g. great auk and gannet) suffered as a result. With increasing 
protection safe sites are once more available, and there is now 



WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? I23 

plenty of room for more at most of the North Atlantic sea-bird 
rookeries. 

However, before we finally admit the primary importance of food 
we must give attention to the question of climatic amelioration in the 
North Atlantic. In the present century there has been a northward 
advance of very many species, which seems to be fundamentally due 
to the effect of the improved weather on the plant life on both land 
and sea; the birds which have moved north have presumably done so 
because the most important elements in their food-supply have moved 
north. These elements are, of course, either the plants themselves 
(which include, of course, sea-diatoms) or other animals which depend 
on plants and which stand between plants and birds. The little auk 
(see p. 60) is becoming extinct in Iceland as a breeding species because 
the edge of the polar pack-ice on which it seeks its main food is moving 
annually farther and farther away, carrying with it the particular 
plankton it is adapted to eat. This is an effect of the climate, but it is felt 
not directly by the little auk but only through its food. Indeed, there 
are only two ways in which climate could directly affect sea-birds, and 
neither of them appear to us to be fundamental in the long run. 

Every now and then a cataclysm of nature may ^^pset the normal 
migrations of birds and kill large numbers of them. Some sea-birds 
are more vulnerable to storms and hurricanes, or sudden changes in 
temperature, than others. One of the most vulnerable to storms is the 
little auk, which, under certain irregularities of the weather, seems 
doomed to "wrecks" or crashes on the coasts of north-west Europe 
or eastern North America. Many hurricanes originate at irregular 
intervals in the Caribbean area and occasionally farther up the sea- 
board to New England. When these take place there is a great deal of 
loss of sea-bird life. It has been adequately described by Murphy 
(1936). While the immediate losses of life are sometimes spectacular 
it seems that, in the long run, they have no fundamental effect on the 
population of birds, though some species are more vulnerable than 
others. 

It is also possible that birds may be directly prevented from breed- 
ing by the weather. It is now clear from the observations of William 
Rowan (1918), Frances Pitt (1929) and others, that abnormal weather 
conditions may suddenly stop breeding activity even if birds have 
arrived at the state of their glands compatible with reproduction. This 
subject has recently been studied by A. J. Marshall (1949 and unpub- 
lished) who examined the effect of the hard winter of 1946-47 on several 



124 SEA-BIRDS 

kinds of small birds. He came to the conclusion that temperature 
and sunshine play a very important role in timing the breeding seasons 
of birds, quite apart from the general factors, such as the length of 
daylight, which zoologists have normally regarded as influencing 
the breeding season. It appears that the influence of temperature and 
sunlight, while important, can be regarded more as determining the 
moment when the trigger is pulled, the cocking of the gun being 
controlled probably by an internal rhythm, and not, as has been 
widely supposed, by the hours of daylight. In any case it is doubtful 
whether climate has ever completely prevented breeding at least in 
the mature sea-bird, by direct action upon the birds' glands. But 
climate does often, indirectly, prevent breeding, particularly in the 
Arctic. It is now commonplace of arctic observation that after late 
springs and in hard weather some, or even all, of the local bird popu- 
lation fails to breed. In our opinion these non-breeding years are 
simply due to the bad weather closing down the food-supply. For 
instance, in very late springs the ice never breaks up in Baffin's Bay 
and the sea-birds of its cliffs cannot find food within operational range 
of their breeding colonies. The same state of affairs undoubtedly 
happens from time to time in east Greenland and Spitsbergen, where 
the state of the ice fluctuates a great deal. In King Charles Land, 
east of Spitsbergen, only nine species of sea- and shore-birds were 
present in 1889 when the ice conditions were bad, whereas 21 species 
were reported in 1898, when they were good. In spite of the work 
of Marshall and others it seems to us that successful breeding in the 
arctic regions depends primarily on whether the adults can find enough 
food (first for themselves and later for their young) within easy reach 
or flying distance of the nesting site. 

To recapitulate previous argument, we find that sea-bird numbers 
like all animal numbers, depend primarily on food ! So we arrive by 
analysis at what is, all along, the conclusion which common sense has 
already indicated! But not all sea-birds are always straining — even 
in the breeding season — at the limits of their food-supply. We have 
seen, for instance, that in the last hundred years the numbers of gan- 
nets in the North Atlantic have been less influenced by the amount 
of food available than by being preyed upon by man, who does not 
behave as a natural predator. Under the present protection the North 
Atlantic gannet is increasing; it may one day return to equilibrium 
with its normal food supply, a position which may mean that its num- 
bers will be as high or higher than when man started his ancient 




Plate 4. Great blackback at nest; Skokholm, Pembrokeshire 



Robert Alkiiuon 



WHAT CONTROLS THE NUMBERS OF SEA-BIRDS? I25 

cropping of its colonies. But the balance of populations is a very 
subtle one, and a lengthy discussion is not called for. We merely wish 
to draw special attention to the importance of food as a controlling 
factor, and to suggest that more critical work ought to be done on this 
neglected subject, and simplest of hypotheses. 



CHAPTER 5 

SEA-BIRD MOVEMENTS 



SINGE SEA-BIRDS cannot nest at sea their life must be a kind of 
compromise, for during a substantial part of the year, in the 
slow-breeding species about half, at least one member of the pair 
has to be in residence at a nest on land which may be some distance — 
perhaps some hundreds of miles — from the nearest place which provides 
an assured supply of food. Other sea-birds operate for shorter distances 
from their base, and the coastal species feed within sight of it. But the 
pelagic or oceanic types may fly some hundreds of miles and possibly 
even a thousand before returning to their nest, even when they are 
incubating eggs; and these birds are very specially adapted to solve 
the consequent problems, — chiefly those of mobility and endurance. 
The oceanic sea-birds have solved these problems of mobility by 
becoming sailplanes as well as power-craft. This fundamental fact, 
although pointed out by Wynne- Edwards in 1935 and no doubt 
familiar to others before him, has been widely overlooked in ornitholo- 
gical circles. Supposing that the oceanic sea-birds relied entirely 
on powered flight, they would only be able to operate to their goal in 
calm weather, and only by the consumption of large amounts of energy 
and, therefore, extra amounts of food. In fact the opposite is the case. 
It is probable that the oceanic sea-bird would find it difficult to get 
from land to the middle of the ocean in calm weather, for the motive 
power of the pelagic sea-bird is provided by the natural winds of the 
great oceans, deflected upwards from the waves. That is probably 
why the evolution of the most important group of oceanic sea-birds, 
the petrels and albatrosses, has taken place in the South Pacific 
and the neighbourhood of the antarctic continent, for in those seas 
nature's winds blow hardest and most continuously, and rollers, 
swells and great waves are permanent features of the surface of the 
waters. The absence of albatrosses in the North Atlantic may be due 
to the fact that the equatorial waters of the Atlantic are, on the whole, 



SEA-BIRD MOVEMENTS 12'] 

rather calm and incapable of providing the albatrosses with the lift 
necessary for them to glide their way through from the south. 

Many descriptions of the flight of the tube-nosed birds exist in 
the literature, and some purport to analyse the motion of these wonder- 
ful birds in aerodynamical terms. Most of them dwell in wonder on 
the effortless flight of these great sea-birds but describe it as flight 
and overlook the really obvious fact that in ordinary rough weather, 
apart from the exercising of the control surfaces of the bird's wing 
and tail and small shifts of its centre of gravity, no important work is 
done by the bird at all. The oceanic travellers make use primarily 
of the components of the wind reflected from the banked sides of the 
waves and swells, and they spend their time making ground by alternat- 
ing the use of this lift with excursions (by gravitational falls) into the 
sheltered trough between the crests of the waves, out of the main 
wind-stream. This is by no means a dead area for it contains various 
moving air systems which are consequences of the impact of the wind- 
stream on the irregular surface of the sea. A sea-bird can move for- 
wards dead against the wind, as anyone who has watched a gull at 
sea will have seen, by using a few wing-beats to gain height, and then 
gliding on a long plane downwards. 

Wind is therefore an advantage from the flying sea-bird's point of 
view. A sudden calm can strand certain ocean birds in mid-ocean, 
especially if heavy-laden with food they may have to sit on the water 
and wait for the wind to get up again. Usually they do not have to 
wait very long. Most sea-birds can make good use of wind of any 
force, and a hurricane in mid-Atlantic probably does little damage, 
if any, to the sea-birds which happen to be there at the time. It is 
only when sea-birds are caught on a lee shore with no sea-room to 
manoeuvre that we get many casualties blown inland by storms. 

This seems to happen to auks quite often, and most particularly 
to the little auk or dovekie. 

Beyond the rather well-marked boundary of the little auk's normal 
winter distribution (see Fig. 19, p. 130, derived partly from the excel- 
lent paper of Rankin and Duffey, 1948), which brings it closer to the 
North Sea coast of Britain than most text-books allow, small numbers 
regularly, and large numbers irregularly, penetrate. On both sea- 
boards of the Atlantic, there are years in which noticeable 'flights' 
of little auks take place within sight of shore or even overland, and 
years in which 'wrecks' occur, both locally and over great stretches 
of coast. In some years there are both flights and wrecks. The evidence 



128 SEA-BIRDS 

shows that these phenomena of irruption and abundance in lands 
beyond the normal winter range are linked with cyclones and gales, 
especially, but not necessarily, those which last for some weeks ; some- 
times a large population has been caught by a sudden gale when 
plankton-fishing rather near a lee shore, and elements have been 
driven ashore or inland before they could find the sea-room necessary 
to escape to one flank or the other. One thing seems certain about the 
little auk irruptions: they are quite irregular, and do not reflect any 
changes in population, as far as can be seen. There is no sign of any 
periodic cycle of abundance in the numbers of any North Atlantic 
sea-bird, except perhaps skuas. 

A dovekie wreck on the U.S. seaboard is not necessarily associated 
with a little auk wreck in Britain, though when weather conditions 
are extraordinary right across the Atlantic they may coincide. When 
wrecks occur the light, small-winged little birds turn up in all sorts of 
places: on reservoirs, lakes, ponds, duck-ponds, rivers, sewage-farms, 
flooded gutters; in greenhouses, down chimneys, in porches, back 
yards, pigsties, gardens, roads, turnip-fields; and are caught by 
foxes, cats, dogs, opossums, raccoons, gulls, ravens, crows, and boys. 
During the 1911-12 wreck of the little auk a doctor in Finsbury met 
one entering his surgery door; it snapped at anyone who tried to 
handle it. The ornithological machine has been sensitive enough to 
detect all important flights and crashes in Britain only since about 1841, 
though it is known that there were flights and great abundance in 
Orkney in 1802-03 or 1803-04 (the records state 'winter of 1803,' which 
is a common kind of ambiguity which has frustrated many a bird 
historian) and 181 1- 12. Since 1841 we list the British, and some of 
the eastern U.S. flights and wrecks as follows: 

Little auk flights and wrecks, Britain and U.S. {italics) 1841-jg^o 
(Years omitted are those in which nothing special was reported.) 

•Winter' of 

1841-42* Big influx, flights and wrecks in October and November, east and south 

England, east Ireland. 
1845-46 Local wreck in the Moray area of Scotland. 

1846-47 Unusually abundant Orkney, and minor flight Aberdeenshire. 

1848-49* Great influx, flights and wrecks in December, Norfolk and Suffolk. 
1860-61 Some inland New England. 

1861-62* Great influx, flights and wrecks in November, east England; many 

north Scotland January, after gale. 
1863-64 Large flights, autumn, Durham and Yorkshire. 



SEA-BIRD MOVEMENTS ISg 

1 866-67 Large flights Tweed area Scotland, and small influx west Scotland (Oban) . 

1867-68 Modest influx and flights west Scotland (Oban, Clyde). 

1868-69 Flights Tweed area Scotland. 

1871-72 ^'Inundation"" of Maine and Aiassachusetts. "Wonderful irruption" of Tay 

area Scotland. 

1874-75 "Very numerous" December and January, Devon. 

1876-77 Abundant Tweed area, December. 

1878-79* Many on Maine coast after December storm. Very big flights and crashes 
in east Scotland and east England after November gale. 

1881-82 "Uncommonly fruitful year" in Tay area Scotland. 

1882-83 "Pretty numerous" in Northumberland. 

1884-85 Flights in north England, November. A modest invasion of western 

Scotland in January. 

1889-90 Flight off Yorkshire coast, January-February. 

1891-92 Notable flight Alassachusetts, November. 

i893"94 Wrecks Ireland and Solway area after November gale. 

1894-95* Perhaps the greatest flights and wrecks in Britain, during and after 
fierce easterly gales in January and February; wrecks most notice- 
able from Tweed to Suflfolk, but also noted Moray area in north- 
east Scotland, and in Ireland (see W. E. Clarke, 1895, etc.). Wrecks 
in Scotland, illustrated Fig. 20, p. 132. 

1896-97 Minor February flight and some wrecks in Tweed and Forth. 

1 899- 1 900* Substantial flights and wrecks in February and March from Dee to 
Yorkshire, and in Solway. 

1900-01 Flights on various parts of east coast from Shetland to Suffolk, Jan.- 

March; biggest, with wrecks, in Norfolk February-March. 

1901-02 Abundant mid-November, Maine. 

1902-03 Many December, Maine. 

1904-05 Flights November to February, Forth and Tay. 

1908-og Flight Fair Isle January-February; Tay area February-March. 

1909-10 Flights Ireland January, and a few England. 

1910-11 Substantial flights in Britain (particularly Norfolk and Suffolk) in 

November (extending also to Germany). 

1 9 1 1 - 1 2 * Great flights and wrecks in Britain in January and February ; England, 
Scotland and Wales. 

1912-13 Flights Norfolk November and January, and Scotland in February 

after south-east gale (see W. E. Clarke, 191 2, etc.). 

1913-14 Alany December, Maine. 

1914-15 Unusual number southerly records Oct. -Nov. (Channel Is., Cornwall, 

Scilly) ; flights and wrecks on both east and west coasts of Scotland 
and Orkney in December and January. 

1915-16 Flights in Scotland and Isle of Man after storms in February and March. 

1916-17 Flights in December in south-east England. 

1917-18 Flights mid-November, Maine. 

1921-22 A crash in Orkney in February. 

1923-24 Flights (but no wrecks) east England. 

1928-29* Flights south-east England (including Norfolk) late November, numbers 
wrecked. 

K 



130 
1929-30 



1930-31 
1931-32 

1932-33 



1936-37 

1939-40 
1942-43 

1945-46 
1946-47 

1947-48 
1948-49* 

1949-50* 



1950-51 



SEA-BIRDS 

Sudden wreck in south-east England 28 December to i January; 

little auk found alive in Round Pond, Kensington Gardens, central 

London. 
Small invasion, November'December, of New Jersey and Virginia. 
Invasions J November-January, of Maine, reaching Massachusetts. 
Probably the greatest flight and wreck on the American seaboard in historical 

times. Influx November from Canada to Florida, some reaching Cuba {Murphy 

and Vogt, 1933), after unusual easterly winds. 
Flights and wrecks on U.S. seaboard, December-January though not as many 

as in 1932-33 {A. Sprunt, 1938). 
Small invasion of North Carolina, November to February. 
Some numbers Yorkshire, November. Small flights and wrecks 

Devon and Cornwall, December and February. 
Flight early December, Maine. 
Rather unusual numbers on coast east Scotland and north-east England, 

January to April. 
Flights, north-east England, particularly November. 
Marked flights, but relatively few wrecks throughout year, coasts 

Scotland, north England, Ireland. 
Wrecks in Channel Islands, south-west England, west Wales, and 

south and west Ireland in February; flights Yorkshire February to 

May (see D. E. Sergeant, 1952) (Fig. 21, p. 134). 
Small wrecks in south England, January. Notable flights and wrecks on 

New England coast. 




Fig. 19 
The distribution of the little auk, Plotus alle. Black: breeding-stations. 
Shades: normal winter sea-range. Outer runbroken line: extent of summer 
sea-range and more fluctuating winter range. Broken line: extreme limit of 

sporadic records. 



SEA-BIRD MOVEMENTS I3I 

These marked * constitute notable invasions of Britain, outstand- 
ing compared with those of neighbouring years. The intervals 
between them however are irregular : 7, 13, 17, 1 6, 5, 12, 17 and 20 
years. 

The extreme limits to which the little auk can get, or can be carried 
by weather, arc shown on Fig. 19, opposite. Strays have penetrated 
the Mediterranean as far as Italy, Sicily and Malta, and one has 
reputedly been seen in Egypt; and some have quite often reached the 
Canaries and Azores. In some winters there is quite an invasion of 
the unfrozen parts of the Baltic. 

In order to carry on a sailing life upon the ocean it is obviously 
necessary for a sea-bird to be adapted to operate for a considerable 
time from base, even though, in ordinary rough weather, it may be 
able to sail very swiftly and make perhaps twenty or thirty miles an 
hour. Some sea-birds, and particularly the tube-nosed birds, in their 
early years before they make their first journeys to breeding cliffs, 
spend certainly two and up to seven years at sea without visiting land 
at all, possibly even without a sight of it. They are therefore adapted 
to drinking salt water and many have been recorded as doing so 
(shearwaters, petrels, auks and gulls). 

Another adaptation of the birds to this kind of life is the power to 
go for long periods without food. It is known that the tube-nosed 
birds (and also the puffin and gannet) can survive, certainly for a week 
and possibly for very much longer, in this way. Indeed, in many 
species the adults only relieve each other at the nest at intervals of 
from four to seven days, and the young of some can be neglected in 
the burrow or nest for about a week without any apparent ill-effects 
or delay in the normal fledging period. 

Between the inshore, or coastal sea-bird, that spends its life within 
sight of land, and often within sight of its breeding-place, and the 
fully oceanic bird, there are many intermediate states. We think it 
best, however, to adhere to the simple classification into the three 
main types for which Wynne-Edwards (1930) is originally responsible. 
The categories are inshore (or coastal), offshore (or marine), and 
pelagic (or oceanic). According to Wynne-Edwards inshore species 
include the cormorant and shag, the scoters, eiders and other sea- 
ducks, most of the smaller species of Larus gulls and, at certain seasons, 
all terns. These are the species which feed almost entirely within 
sight of the shore, and we think that to them could certainly be added 
the black guillemot, the divers in winter, and the red-footed and blue- 



132 



SEA-BIRDS 



9« 8° 7° i>' 5* 4" 3° 2° 1° o' 



100 KM 12 



11 



4 5 



100KM 




10 



12 



7 



lAT. 

6o- 



sr 



V' 



56° 



iS' 



Fig. 20 
A famous little auk wreck in Scotland, that of 1894-95 replotted from 

W. E. Clarke (1895): 

#: one; ■ : several; *: Tnany 

faced boobies of the tropics, though these last two occasionally work a 
little farther afield. 

\Vynne-Edward's offshore birds include the gannet, all the auks 
except the little auk, and two Lams guUs^ the lesser blackback and the 
herring-gull. We would suggest that the black guillemot is perhaps 
more coastal and that the puffin is somewhere between an offshore and 
a pelagic species. Offshore birds, by definition, are those which obtain 
their food within the continental shelf which, in the Atlantic, is, 
generally speaking, marked by the lOO-fathom line and is at most 
200 miles from land. Of course, birds do not know where the 100- 
fathom line is, but it coincides practically with the edge of human 
fishing-grounds and the food changes very quickly beyond this point. 




R. M. Lorkley 

Plate Xllla. The all-black Bulwer's Petrel (adult) breeds numerously in the Desertas, 

Madeira 



b. Bulwer's Petrel dav-old chick, Desertas, Madeira 



R. M. LnckUy 









Plate XlVa. Deserted by its parents : the young Manx Shearwater at ten weeks' 
old, about to leave the burrow 

b. Deserted by its parents: the young Fulmar at seven weeks' old 



R. M. Lockley 



A/. Lockley 




"••*"t 



SEA-BIRDS 133 

Of the marine birds the great blackback does not usually venture as 
far out as the lesser blackback and herring-gulls. (We have seen 
a few lesser blackback and herring-gulls at Rockall, which is 191 miles 
west of the St. Kilda islands and nearly 300 miles north-west of Ireland; 
it is however "land" and it lies on a fishing bank of its own.) In 
the parts of the North Atlantic most familiar to British and American 
ornithologists the most typical inhabitants of the marine or offshore 
zone are the razorbill, guillemot, lesser blackback, herring-gull,puffin 
and gannet; in the tropics the brown booby. The last three of these — 
the puffin, gannet and brown booby — are perhaps more oceanic 
than the others and more inclined to be found also in the next zone, 
which Wynne-Edwards names pelagic but which we shall generally 
here call oceanic. 

This zone contains some all-the-year-round birds, and some seasonal 
birds. The Manx shearwater, which is also very much an inhabitant 
of the offshore zone, is found here in greater numbers than early 
workers have recognised, and can also certainly be classified as an 
oceanic bird. Among the important seasonal birds are the arctic 
tern, which makes a twice-yearly crossing of the Xorth Atlantic, the 
four species of skuas, which also make twice-yearly seasonal crossings, 
and the two species of ocean-wintering phalaropes. The all-the-year- 
rounders, i.e. species which use the open ocean at all times when they 
are not actually engaged in breeding and return to it when they are 
off-duty, even during the breeding-season, include almost all the 
tube-nosed birds; particularly in the North Atlantic, Leach's petrel, 
the storm-petrel, the fulmar, the Tristan great shearwater, the North 
Atlantic shearwater, the sooty shearwater, Bulwer's petrel, the frigate- 
petrels and the gadfly petrels. The only oceanic gull is the kittiwake. 
The little auk might fall into this category, but it has a food-connection 
with the ice-front which necessitates a rather special definition of its 
distribution. In general, as Wynne-Edwards points out, each of the 
three chief families of northern sea-birds is the main possessor of one 
of these three zones. The gulls largely possess the inshore zone, the 
auks largely the offshore zone, the tubenoses the oceanic zone. 

During the present century a number of ornithologists have crossed 
the North Atlantic and plotted accurately the sea-birds which they 
encountered, checking their position with the ship's log. Recently 
E. M. Nicholson (1950,1951) has made a classification of the whole of 
of the North Atlantic into ten-degree blocks, for which he has provided 
a practical and easily memorable nomenclature (Fig. 55^ p. 291). 



MORE THAN 

50 BIRDS RECORDED 

20-50 



Wa 



5-10 



Ml LE5 



□ 



NUMBERS 
UNKNOWN 

INDIVIDUAL 
RECORDS 




Fig. 21 
A little auk wreck mainly in England, Wales and Eire, that of 1949-50 

from D. E. Sergeant (1952) 



SEA-BIRD MOVEMENTS I35 

This most helpful piece of work has been widely accepted throughout 
the ornithological world and there is no doubt that we are beginning 
to understand the distribution of birds in these waters, and beginning 
to see that the hidden topography of the sea^ which we have analysed 
in our first chapter, is reflected in the distribution of sea-birds, which 
has, for most species, a well-marked pattern, with seasonal changes 
of an orderly kind. A recent important follow-up to Wynne-Edwards's 
pioneer work on the distribution of sea-birds at sea, is the paper by 
Rankin and Duffey, published in 1948, based on many transects made 
by them when they were on operational duties in the Royal Navy 
during the last world war. A pioneer investigator of the sea distribu- 
tion of the North Atlantic sea-birds was the late Poul Jespersen (1924, 
1929, 1930) whose excursions were further into the tropics than those 
of other workers. It is now possible to make preliminary analyses and 
maps as a result of these and other investigations which show not so 
much a fortuitous distribution of observers as a real distribution 
of the observed. Derived from all the available literature, and from 
certain unpublished notes of Eric Duffey, one of us has made six maps 
showing the distribution of the fulmar at sea on a two-monthly basis. 
Every observation of at least one certain fulmar was plotted as accur- 
ately as possible. The result (Fisher, 1952) shows not only the distribu- 
tion of the fulmar through the seasons but the amount of information 
on a sea-bird that is now generally available. 

While nearly all the inshore sea-birds are either resident or migrat- 
ory it seems necessary that the word "dispersive" should be used to 
describe at least some of the offshore and most of the pelagic species. 
This word is not a contradiction of the word "migratory," because 
many species are undoubtedly both dispersive and migratory, if we 
use migratory to mean "making a regular journey in a particular 
direction," and dispersive to mean "scattering in no particular 
direction." In the early days of marine ornithology the word dispersive 
was applied to many species. Quite early in the present century, 
when the ringing recoveries of the guillemots began to mount up, it 
became clear that a large number of British breeding birds made 
northward journeys at the end of their breeding season, often north- 
eastwards to the coast of Norway, instead of the expected southward 
journeys. It was discovered, too, that even the inshore coastal terns, 
particularly the young, sometimes made northward journeys, the 
first journeys of their lives. Gannets, too, were found by ringing returns 
to go north, south, east and west of their gannetries. It was thought 



Fig. 22 
Distribution of the species or superspecies, 
Catharacta skua, the great skua. Breeding-places 
embraced by black lines and shaded. Dots 
represent some sight or specimen records. It is 
possible that races from both northern and 
southern hemispheres may winter on the same 
parts of the central Atlantic 




138 SEA-BIRDS 

that these dispersive birds simply voyaged in no particular direction 
until they found adequate supplies of food. Some of the Norway 
recoveries however may have been due to the equinoctial gales from 
south-west. 

It is now known that a proportion of our gull population simply 
attaches itself to the inshore and shallow sea fishing fleet and follows 
it throughout the winter wherever it goes. (This does not apply so 
much to the lesser blackback, which is a more truly migratory species — 
p. 250.) Gannets, which are also partly parasitic on the fishing fleet, 
stay round the British coast when they are adult ; they do not normally 
feed within sight of their gannetry and from the ringing returns can 
be shown sometimes to wander quite close to other gannetries. The 
adults especially are truly dispersive. It was thought that the fulmars, 
Leach's and storm-petrels were dispersive because they disappeared 
into the ocean when their breeding season was over, and were seen to 
be scattered fairly evenly over certain parts of it. Unfortunately we 
have as yet learned little from marking storm- and Leach's petrels, 
but the first important results from marking fulmars have now come 
to hand and they show that some at least of the young fulmars from 
West Greenland and from St. Kilda go to the Newfoundland Banks 
within a few months of fledging. This must be regarded as a migration, 
and it would certainly appear that the young fulmar, like the young 
gannet, is migratory, even if its parent is dispersive. 

The gannet is seldom seen beyond the Continental shelf — i.e. the 
hundred-fathom line. The many ringing recovery records analysed 
by Thomson (1939) show that the marked winter movement of gannets 
south from Britain along the Biscay, Portugal and West African coasts 
is composed of adults and young, and that it is predominantly the 
young (particularly those in their first year) that go on to Africa; they 
reach Senegal. The Abbe Parquin (Mayaud, 1947) came across a 
huge concentration of gannet flocks on 16 January 1940 off the coast 
of Morocco from Casablanca to Mogador. This "he estimated at 
more than 100,000 individuals," which approaches half the world 
population! Gannets have been seen, in numbers that cannot in all 
cases be regarded as casual, in the Adriatic, and even off Egypt and 
Palestine. 

To the north the disperal of the gannet sometimes reaches distances 
of a thousand miles or more from its breeding-colonies. It visits the 
coast of Norway up to the Lofotens (often in winter) and casually 
to Varanger Fjord and beyond. It has been seen fishing near Bear 



SEA-BIRD MOVEMENTS I39 

Island (Bertram and Lack, 1933): one was seen at Jan Mayen on 
21 July 1900 (G.KolthofF, 1901). There are only four certain gannet 
records for Greenland (Horring and Salomonsen, 1941), three from 
the south-west coast and one from Scoresby Sound on the east side. 
Nevertheless the gannet does appear to penetrate Davis Straits a little 
distance, also sometimes Hudson's Strait, for the Eskimos of Ungava 
see it occasionally (B. Hantzsch, 1928) and T. H. Manning (1952) 
saw, in August 1947, three or four birds that he believed to be gannets 
at the mouth of the Shagamu River, south-west Hudson's Bay. We 
have one extraordinary (hitherto unpublished) record from the 
Canadian Arctic beyond Davis Strait, from Jones Sound which enters 
Baffin's Bay as far north as 75°N. Here, on 23 August 1937, while 
excavating the old Eskimo village at Cape Hardy on the north coast 
of Devon Island, T. C. Lethbridge and his companions (who were 
all familiar with the species) saw several gannets flying in line quite 
close to them. 

The West Atlantic breeding birds do not disperse in quite the same 
way as the East Atlantic birds in winter, for the St. Lawrence popula- 
tion appears to go south for the winter, adults and young together. 
None goes north: there is no record whatever of any gannets along 
the Atlantic coast of Labrador from the Straits of Belle Isle to Davis 
Strait (O. L. Austin, 1932), which suggests that the birds seen in 
Greenland and the Canadian Arctic may have dispersed there from 
Iceland or from some other East Atlantic headquarters. In winter 
gannets are more common off Virginia than off Cape Cod ; the birds 
range far south into the Caribbean, regularly to Florida and Cuba 
and into the Gulf of Mexico, occasionally as far as the Mexican coast, 
and reputedly to Trinidad. So the West Atlantic gannet is a true 
migrant. The guillemot and even more so the razorbill, Hke the young 
gannet, are migratory: both enter the Mediterranean and penetrate 
eastwards as far as Italy and the Italian islands. 

The sea-birds which make the greatest journeys of all are the great 
and sooty shearwaters which visit us from the southern hemisphere 
and our own northern-hemisphere-breeding Manx shearwaters, arctic 
terns, skuas and phalaropes. All cross the open ocean at the Equator 
on their way to their objectives in the southern hemisphere. Lately 
it has been proved that the Manx shearwater makes a diagonal migra- 
tion, from the British Isles to South America (region of Buenos Aires 
and Rio de Janeiro, where two individuals ringed at Skokholm 
have been recovered) . Crossing the line of the shearwater migration 



1 40 SEA-BIRDS 

is the well-marked diagonal fly-way of the arctic tern between New- 
foundland and North- West Africa, which may involve a very large 
proportion of the population of this tern in the eastern part of North 
America. The arctic tern's migrations, indeed, are not only rather 
complicated, but certainly more spectacular than those of any other 
sea-bird; the little bird probably travels farther in the course of its 
year than any animal in the world, except perhaps some whales. Its 
travels are worth describing in some detail. 

It was previously thought by some workers, e.g. Seebohm (1885), 
that, in spite of its circumpolar breeding-distribution, the arctic tern 
had "not yet discovered the existence of the Pacific Ocean." Certainly 
there seem to be rather few records on the eastern coast of the Pacific, 
and practically none on the west side south of Kamchatka. But this is 
probably because the arctic tern's passage is largely at sea; stragglers 
have indeed been recorded in the Hawaiian islands and in the North 
Island of New Zealand. The passage is detectable oflf and along the 
California coast, and quite a number are found offshore along the 
coasts of Peru and Chile. Even allowing for the relative numbers of 
observers (there are practically none at sea in the Pacific), it seems 
clear that the Atlantic passage is the greater, however. In late summer 
and autumn very many are seen crossing the North Atlantic trans- 
ocean shipping routes, and most, though not all, are passing at that 
time from north-west to south-east. It would seem that many of the 
arctic terns that breed in the north-west corner of the Atlantic, and 
round the arctic waters that communicate with it, pass on a slant to 
make their passage on the east side of the Atlantic. The (now famous) 
ringing recoveries of arctic terns marked in Labrador (on the Red 
Islands in Turnavik Bay) by O. L. Austin bear this out. One, marked 
as young on 22 July 1927, was recovered at la Rochelle in France on 
I October 1927; the other, marked on 23 July 1928, was found dead 
at Margate, fifteen miles south-west of Port Shepstone, in Natal on the 
south-east coast of Africa, on 14 November 1929 — it has flown at least 
nine thousand miles in ninety days. A tern ringed on Eastern Egg 
Rock in Maine on 3 July 1 9 1 3 and recovered at the mouth of the river 
Niger in August 191 7 is now known to be an arctic tern (not a common 
tern as was originally recorded). Three birds marked as young at 
Machias Seal Island, belonging to New Brunswick but on the borders 
of Maine, have been recovered across the Atlantic (O. Hawksley, 1949). 
One marked on 20 July 1935 was captured near St. Nazaire in France 
on 8 October of the same year. One marked on 5 July 1947 was found 




Plate XVa. Brown Booby, 

Fort Jefferson, Dry Tortugas, 

Florida, U.S.A. 

{Roger T. Peterson) 



b. Blue-faced Boobies, Dry 
Tortugas, Florida, U.S.A. 










■9^- 



•s^:--\ - 



\ 



V 



y 






. :,J«^'' 



'0^:S 



-*5p£^JNr~- 



/?. M. Lockley 

Plate XVIa. Mutual display of mated Gannets continues throughout the breeding season 

('Grassholm) 



b. The feeding process in the gannetry (Grassholm) 



R. M. Lockley 




J 




'^n 







-«%.. -;>^*' 



':^^' 






■is- J^^ 






SEA-BIRD MOVEMENTS I4I 

on 10 November 1948 near Wilderness in Eastern Cape Province, 
South Africa. One marked on 18 July 1948 was picked up dead 
towards the end of September of the same year on the hills near 
Kylestrome in West Sutherland, Scotland. 

Two of the young arctic terns hatched in Disko Bay, West Green- 
land, have been recovered. One ringed in July 1947 was collected 
a year later on the shore of James Bay, Ontario, where it was occupying 
a small ternery as a non-breeder. The other, ringed on 7 August 1949, 
was recovered in Gloucestershire on 20 October of the same year. One 
British nestling marked in Northern Ireland on 13 June 1941 was recov- 
ered at Lobito, Angola, in the south-west of Africa in February 1942. 

The latest West Greenland arctic tern recovery involves the longest 
journey of any bird ever recorded by ringing. A juvenile ringed at 
Ikamiut in the Christianshab district on 8 July 1951 was recovered 
newly dead in Durban Harbour, Natal, South Africa, on 30 October 
of the same year. It had flown over eleven thousand miles in less 
than three months after first taking wing. 

These add up to an Atlantic crossing of at least some of the North 
American elements, and to a northward penetration into the Indian 
Ocean once the birds have rounded the Cape (Fig. 23, p. 142). But 
though we now know that some of these corner-turners reach Mada- 
gascar, we are also now quite sure that large numbers continue from 
the south Atlantic on to the Antarctic; and that some, also, do not 
cross the Atlantic first, but pass down, and off, the coasts of Brazil 
and the Argentine to this goal. Many ornithologists have been, quite 
properly, hesitant about accepting the arctic tern records in the 
Antarctic — particularly in view of the chance of confusion of sight 
(and even some specimen) records with the two southern breeding 
species. Sterna vittata, the antarctic tern, and S. hirundi?iacea, the South 
American tern. However, the facts are now accepted by such critical 
workers as R. C. Murphy, and have been abundantly augmented in 
the season 1946-47 by ^V. H. Bierman, an experienced ornithologist 
who was ship's surgeon to the Dutch whaling-ship Willem Barendsz- 
(Bierman and Voous, 1950). Some of the certain observ^ations of 
arctic terns round the Antarctic Continent, and in the oceans and lands 
between it and the breeding-grounds of this extraordinary^ bird, are 
plotted on fig. 22. The birds particularly inhabit the pack-ice and 
the neighbourhood of bergs, and feed in the 'leads' and near the bergs, 
where whale-krill (particularly Euphausia) is plentiful, in much the 
same way as they do in the Arctic. 




Fig. 23 

Distribution and Atlantic migration of the arctic tern, Sterna paradisaea 
Dark shading: breeding-distribution. Dots: some certain sight or specimen 
records. Lines connecting ringing: to recovery places do not of course 
necessarily represent actual routes taken 



SEA-BIRD MOVEMENTS I43 

From the British Isles the arctic tern is totally absent from Decem- 
ber (usually November) to March, while it is engaged on this great 
southward visit. When on passage through Britain it moves usually 
by coastal routes; and some Baltic and Frisian birds (by ringing 
records) join up with the passage on the coast of eastern England. 
In some years arctic terns join the marked inland passage of common 
terns along the English river- valleys. But beyond Britain most of the 
passage becomes oceanic, and the records in inland Europe and the 
eastern Mediterranean are very scanty. 

The four skuas, which in the winter are generally parasitic on other 
sea-birds, also (like the arctic tern) make long journeys which involve 
entering and crossing the open oceans. To understand their migrations 
it is necessary to consider also their breeding-distribution in some 
detail. The largest of them, the bonxie or great skua, Catharacta skua, 
is one of the few birds with a bipolar distribution. We think it likely 
that this interesting species (or superspecies) originated in the north, 
and colonised the south where it evolved into a bird of more gull-like 
form and habits than the other skuas; and that the presence of a 
breeding-outpost in the North Atlantic is possibly quite a recent 
development, and probably derived from the main subantarctic and 
antarctic population. 

Most authorities consider all the bonxies to be of one species; 
but it is possible, as Murphy and others point out, that two of the 
southern forms, hitherto classed as the subspecies C. skua maccormicki 
and C skua lonnbergi, may breed on the same islands in the South 
Shetlands, in which case they should be regarded as separate species, 
even if they are overlapping end-members of a subspecies chain (see 
p. 39). If the world's bonxies do not all belong to one species, they 
certainly form one superspecies; and the differences between the 
northern C. skua skua and the Falkland Islands and Chilean races of 
the antarctic skua, C. skua antarctica, and C, skua chilensis are not great. 
The distribution of the bonxies, on their breeding-grounds and at sea, 
is shown in Fig. 22 (p. 136). It will be seen that southern skuas cross 
the equator in the Pacific, and nearly reach it in the Indian Ocean: 
those which travel up the eastern shore of the Pacific as far as the 
United States and even British Columbia are C. skua chilensis; one of 
the great skuas taken in Japan has been positively identified as the 
south polar skua C. skua maccormicki — not of the race lonnbergi which 
breeds south of New Zealand and thus much nearer Japan. This 
form {lonnbergi) has not so far actually been found in the Pacific north 



1 44 SEA-BIRDS 

of the North Island of New Zealand, and may be more sedentary in 
ranging-habits than the south polar skua. The skuas seen at sea in 
the Atlantic south of the equator have been identified on the west 
side as belonging to the Falklands race antarctica; on the east side the 
affinities of the Tristan-Gough breeding-population are obscure 
(they most closely resemble lonnbergi, it seems) and the identity of the 
race commonly observed off the west coast of South Africa is unknown, 
as is the form noticed chasing terns in the Seychelles in the northern 
Indian Ocean. 

There is so far no formal proof that the southern bonxies of today 
penetrate to the North Atlantic, though they must have done so on 
occasion if the theory of the antarctic origin of the British-Iceland 
population be the correct one. Bonxies have been seen between the 
equator and the West Indies in April and May, off the West African 
coast south of the Cape Verde Islands in November, January and 
February, and in the central part of the Sargasso Sea between October 
and December (not in any other month). But whether these are 
southern or northern is not certain, as none has been collected. North 
of these latitudes bonxies spread widely over the sea, parasitising gulls 
and terns, from New York to the Straits of Gibraltar, and there is no 
doubt that they are northern bonxies; a bird ringed at Hermaness, 
Shetland, has been recovered near Boston (Massachusetts), and birds 
from Noss, also in Shetland, have been recovered in Spain and Portugal. 
Bonxies haunt American waters through the summer, for instance the 
fishing-grounds of Nantucket and the Newfoundland Banks; but the 
suggestion that these may — because of the season when they are 
seen — be southern birds must be resisted. Indeed, they wander far 
at all seasons, for their breeding-grounds are confined to south Iceland, 
the Faeroe Islands, Shetland and the island of Hoy in Orkney, while 
foraging birds are often seen west, north and east to Labrador, Green- 
land, Jan Mayen, Bear Island, Spitsbergen, and have been observed 
as far as Novaya Zemlya. A few birds enter the Mediterranean, 
though they are not regular in any part of it east of Gibraltar. 

Outside the Iceland-Britain area, there are only rumours of North 
Atlantic bonxie colonies. Ludwig Kumlien (1879), in his exploration 
of Baffin Island, supposed the presence of a colony on Lady Franklin 
Island, off" the south-east corner of Baffin Island; but there is no 
modern evidence of a colony anywhere in this area, or — as has also 
been rumoured — in south Greenland. 

In south-east Iceland the great ice-cap of Vatnajokull drains into 



Fig. 24 
Distribution oiStercorariuspomarinus, the pomarine 
skua. Breeding area embraced by black line 
and shaded overland. Dots represent some sight 
or specimen records. It is "probably regular in 
New Zealand." (Fleming and others, 1953). 




146 SEA-BIRDS 

a maze of rivers, of which many short ones lie between it and the sea, 
flowing erratically, depending on the temperature and melting 
(sometimes also on volcanic eruptions), through great, flat, wide aprons 
of morainic lava-sand, in places ten miles wide. These aprons of sand 
are the chief breeding-habitat of the bonxie in Iceland; its headquarters 
is on the sand- waste BreiQamerkursandur, and there are many on 
the larger Skei6ararsandur, and some on the little waste of Steina- 
sandur. Other parts of Iceland have a few breeding great skuas, but 
not many nest on moorland resembling their typical habitat in Shet- 
land. In the Faeroes and Britain the present situation is that annually 
there are just over a hundred nests in the Faeroes, distributed over 
eight islands, the vast majority being on Streymoy: about a thousand 
nests in Shetland, distributed over nine islands, the vast majority 
being on Foula, Unst, Yell, Hascosay and Noss: and over twenty 
nests on Hoy in Orkney. It seems unlikely that there are over ten 
thousand living northern bonxies in the world; yet the bird is so 
conspicuous that it features very frequently in at-sea observations and 
transects of the North Atlantic. 

The pomarine skua (we prefer this name to pomatorhine skua), 
Stercorarius pomarinus, has the most restricted distribution (Fig. 24, 
p. 145) of the three smaller species. Its breeding-range is typically 
arctic, and confined to tundra countries, and it is quite absent from 
the arctic sector between West Greenland and Novaya Zemlya, 
except for what appear to be casual breeding-records from the Mur- 
mansk coast and Kanin Peninsula in European Siberia, and Franz 
Josef Land. It is doubtful whether it breeds anywhere in Labrador; 
it is probably only irregular in Alaska south of the Arctic Circle, and 
nobody seems to know anything about its status in Kamchatka (a 
part of the Palearctic from which little information about birds seems 
to be available). 

It is now possible to derive an indication of the ofl'-season distri- 
bution of pomarine skuas from a plot of recorded observations of 
birds on land at sea. What must clearly be quite a considerable 
proportion of the world population enters the North Atlantic via the 
Norwegian Sea, and migrates along the shores of Britain (particularly 
the eastern shores), as well as more directly to mid-ocean. Pomarines 
reach the Nova Scotia and U.S. seaboard; and pass along the western 
North Atlantic shore as far as Florida, the Bahamas and North Cuba; 
and there are records from the Sargasso Sea, and one from Dutch 
Guiana. On the eastern side there seems to be a small, but fairly 



SEA-BIRD MOVEMENTS I47 

regular, overland passage to the Caspian, Black Sea and Mediter- 
ranean; and along the east Atlantic shore, and some distance off it, 
they travel in numbers to the tropical West African coast in the neigh- 
bourhood of the Rio de Oro and Cape Verde. Here there is a significant 
concentration of pomarine skuas, remarked upon by many different 
observers; and some go farther, towards the Gulf of Guinea and even 
beyond, for there are records from Walvis Bay in South Africa and 
from St. Helena. 

In the Indian Ocean the pomarine skua has, as far as we can 
find, only been recorded from Burma. In the Pacific it coasts along 
the American side to Mexico, has reached the equator at the Galapagos 
Islands and crossed it to Peru. On the Asiatic side it is found in the 
Kuriles, off Japan and possibly off northern New Guinea; and it has 
reached northern and eastern Australia; one straggler is recorded 
from North Island, New Zealand. 

The arctic skua, Stercorarius parasiticus^ has much the widest 
breeding-distribution of all skuas, extending from the High Arctic to 
the moors of northern Scotland, and the forest zone of northern Europe, 
Asia, and America. Comments on the map (Fig. 25, p. 148) can be 
confined to particular areas; the arctic skua is probably the only 
skua that breeds regularly in Labrador, though much has still to be 
discovered about its exact distribution on that coast. In Greenland 
it breeds on three well-defined coastal strips: the southern part of the 
west coast; the Thule district at the entrance to Smith Sound; and 
the east coast between Scoresby Sound and Hochstetter's Foreland; 
not, apparently, elsewhere. It is the only skua which breeds regularly 
on Jan Mayen. In Europe its southern limit was formerly Denmark; 
it still breeds on the fells and coastal moors of Norway south to its 
southern tip, Lindesnes, but is relatively rare in Sweden — even in 
arctic Swedish Lapland, where the long-tailed skua is commoner. It 
breeds, however, in western Finland and on the Aland islands in the 
Baltic. It is abundant on the moors and sands of Iceland, and on all 
the islands of the Faeroes. In Britain it now breeds regularly in Shet- 
land, Orkney, Caithness, the Outer Hebrides and the Inner Hebridean 
island of Coll. In Shetland it is widespread, nesting in at least three 
parts of Mainland, and on Mousa, Noss, Yell, Fetlar, Hascosay, Unst, 
Foula and the Fair Isle. In Orkney it breeds in Hoy, and has bred 
in Papa Westray since about 1925; it formerly bred in Eday and 
Sanday. The Caithness and Coll colonies are small and fluctuating, 
and the Outer Hebridean birds are widely scattered over the maze 



Fig. 25 
Distribution of Stercorarius parasiticus, the arctic 
skua. Breeding area embraced by black line and 
shaded overland. Dots represent some sight 
or specimen records. Fleming and others (^1953) 
show that it is regular in New Zealand and 
reaches the Chatham Is. 




SEA-BIRD MOVEMENTS I49 

of land and water from Lewis to South Uist. Wlien Thomas Pennant 
travelled on his famous tours in Scotland he found arctic skuas nesting 
on Islay and Jura in 1772; but they have bred since only sporadically 
on these islands, e.g. on Jura in 1890 and 1939 and on Islay in 1922. 
At least one pair bred regularly in Sutherland until the end of the last 
century, but now it is sporadic there. It has nested sporadically also 
in Tiree (1891), Argyll (c.1931) and West Inverness (1928-33). 

At sea the arctic skua has been called "the unfailing attendant of 
the arctic tern," and follows this and other species across the equator 
in both Atlantic and Pacific. The plot (Fig. 25, opposite) of at-sea records 
in the North Atlantic, as compared with other ocean areas, reflects 
the distribution of observers rather than that of skuas; but there is 
no doubt that the arctic skua passes to its winter waters by ocean 
passages. It reaches the Straits of Magellan by the Pacific and probably 
also by the Atlantic, has been recorded from St. Paul Rocks and St. 
Helena, and reaches the Cape in Africa. It is recorded from tropical 
\Vest Africa, though it does not appear to concentrate around and south 
of Cape Verde as does the pomarine skua. It passes along the U.S. 
seaboard to the Mexican Gulf, North Cuba, the Bahamas and the 
Sargasso Sea, and has been recorded from the Grenadines in the West 
Indies. It passes commonly along both east and west British shores, 
and to a certain extent also overland in Europe to the Mediterranean- 
Caspian line; and some elements reach the southern Red Sea, the 
Persian Gulf, and the Mexican coast. West Pacific birds reach New 
Guinea, Australia, New Zealand and Chatham Island. 

The breeding-distribution of the long-tailed skua, Stercorarius 
longicaudus is not the most restricted, but its at-sea distribution is the most 
mysterious (Fig. 26 p. 150). Its population is much smaller than that 
of the arctic skua, and probably smaller than that of the pomarine 
skua. Its nesting distribution is wide through the arctic, but scattered 
and over vast regions (see map) sporadic; it extends south of the 
Arctic Circle to the Dovre Fjeld area, or even farther south in Norway. 
It breeds south to Nunivak Island in Alaska, to York Factory^ in 
Hudson's Bay, probably not to northern Labrador and Iceland; the 
evidence is unsatisfactory from these areas. It does not breed in south 
Greenland, or on Bear Island and many other arctic islands; in general 
it nests only where there are small rodents available, particularly 
lemmings, though it does not need these, for it has successfully nested 
on Jan Mayen (once, in 1900) and several times in Spitsbergen (e.g. 
1 931), where there are no rodents. One of us was stooped at by a 



150 



SEA-BIRDS 




Fig. 26 
Distribution of Stercorarius longicaudus, the long-tailed skua. Breeding area 
embraced by black line and shaded overland. Dots represent some sight or 

specimen records 



long-tailed skua in Spitsbergen in 1933, while he was looking for 
arctic skuas' nests, but though the bird was clearly defending a territory 
its nest was not found. 

Like the other skuas, the long-tailed skua passes to its Atlantic 
winter waters by ocean routes, though it is often seen off British shores, 
and a strong element passes south down the North Sea and through 
the Channel. Whether the inland records in Europe indicate a real 



SEA-BIRD MOVEMENTS I5I 

(small) overland passage to the Mediterranean, or are merely casual, 
is not yet clear. In the Atlantic the species reaches the Sargasso Sea 
(Jespersen, 1930), has been seen in mid-ocean between the Amazons 
and Cape Verde, and has once only (as far as we can discover) been 
seen off tropical West Africa — four together near the Cape Verde 
Islands on 8 May 1947 (Bierman and Voous, 1950). The only observa- 
tions of this species in the southern hemisphere derive from Murphy 
(1936), who records long-tailed skuas off Peru, Chile and Argentina 
between October and December, and Wetmore (1926) who found them 
harrying Trudeau's terns, Sterna trudeauiy off the Buenos Aires coast 
of Argentina in December. We can find no record whatever of this 
species from the Indian Ocean, Australasia, or the West Pacific south 
of Japan; on the east Pacific shore long-tailed skuas — perhaps on their 
way to Chile — pass along the coasts of British Columbia, the western 
United States, and Mexico. But the winter quarters of this interesting 
species remain generally mysterious. It is possible that the long-tailed 
skuas scatter more widely than the others, and do not usually gather 
in numbers over special waters. 

We cannot leave the subject of sea-bird movements without a 
glance at what are perhaps the most interesting and specialised to 
all the secondary sea-birds — the phalaropes, the only waders that 
spend part of their lives as true sea-birds. 

There are actually three kinds of phalaropes, but Wilson's phal- 
arope, Steganopus tricolor, is never a bird of the open sea. The others, 
which are both known in Britain, winter in the wide ocean, where 
they hunt and swim for surface-plankton; an adaptation which 
continues to astonish those who meet them under such circum- 
stances. The larger of the two, the grey phalarope, Phalaropus fulicarius 
(known in North America as the red phalarope) is a pan-arctic breeder 
which has been recorded as nesting at the highest possible latitudes 
all round the mainland and islands of the Polar Basin; in fact it has 
been found breeding in all those lands nearest the Pole save Svernaya 
Zemlya off Siberia and the islands north and west of Melville Island 
in the Canadian Arctic; and might be found on these if they 
were well explored. The southern boundaries of its breeding-distribu- 
tion do not extend far beyond the coastal tundras of Greenland, the 
Canadian North- West, Yukon, Alaska and Asiatic Siberia; it is not 
found breeding in Alaska far south of the mouth of the Yukon, or in 
Hudson's Bay (except on its north-western shore), or in Labrador, 
or on the European arctic mainland; indeed in Siberia-in-Europe 



152 SEA-BIRDS 

it breeds only very doubtfully on Kolguev and Waigatz, though 
certainly, and in places abundantly, on Novaya Zemlya, Franz Josef 
Land and Spitsbergen. It nests in small numbers, and perhaps not 
every year, on Bear Island, and has a stable and fairly large breeding 
population in south Iceland; it occasionally breeds in other parts 
of Iceland. It has not been proved to nest on Jan Mayen. 

The breeding-range of the red-necked phalarope, Phalaropus 
lobatus, known in America as the northern phalarope, is actually less 
northerly than that of the grey phalarope, though it nests in many 
parts of the High Arctic. Its range stops short of Devon and Ellesmere 
Islands in the Canadian Arctic, of the northern two-fifths of Greenland, 
and of most of the islands of the Eurasian half of the Polar Basin, 
though it breeds in Novaya Zemlya, Kolguev and Waigatz, and has 
occasionally bred in Spitsbergen. It is not on the breeding-list for 
Bear Island or Jan Mayen. Iceland is an headquarters of it; thousands 
nest on the eutrophic oasis-lake of Myvatn in the north, and these 
tame, pretty birds of Odin nest even on a public lake in the middle of 
Reykjavik, Iceland's capital. The southern limits of the creature's 
breeding-range are not easy to define, for the outposts are very 
scattered; it is clear that there are some in north-west Ireland, in 
the Hebrides, and in Orkney, Shetland and the Faeroes ; but the situation 
is obscure in Russia, where elements may reach the Kirghiz Steppes, 
and do reach northern Sakhalin. In North America the red-necked phal- 
arope breeds in Newfoundland Labrador, but not in Newfoundland, 
reaches its farthest south as a nesting species in James Bay, and has 
scattered outposts in the interior of the North-\Vest, Yukon and Alaska. 
But the main breeding-grounds are along the coastal tundras of the edge 
of the Polar Basin, and by the mouths of the great north-flowing rivers. 

The winter-quarters of the two sea-phalaropes have until recently 
been little known, and they are still somewhat mysterious. The present 
extent of our knowledge is plotted on Figs 27 and 28 (pp. 154, 155). 
In the west Pacific we know that the grey phalarope reaches Japan, 
but whether flocks winter in the South China Sea or other Pacific 
waters to the south of Japan and east of the Philippines is quite 
unknown. The red-necked phalarope definitely enters those waters, 
and flocks have been seen oflf North Borneo, northern New Guinea, 
and further south among the East Indies in the Banda Sea. Phalarope 
red-necked is recorded from Malaya,* and two from New Zealand; 

*J. Delacour (1947) says the red-necked phalarope "winters in the seas south of 
Malaysia" — presumably therefore in the eastern part of the Indian Ocean. 



SEA-BIRD MOVEMENTS I53 

four grey phalaropes have also been found in New Zealand — the only 
West Pacific records south of Japan. 

In the east Pacific both species travel down the western seaboard 
of the United States, and have been recorded as stragglers to Hawaii. 
The red-necked phalarope appears to have a winter sea-headquarters 
off the coast of Peru, though elements certainly carry on to Patagonia 
and have been found inland in Bolivia and Argentina. The grey 
phalarope appears to disperse more over the ocean, having been found 
in the Galapagos Islands, and having been seen by Poul Jespersen 
(1933) many times on a voyage from Panama to the Marquesas. A 
headquarters appears to be off the coast of Chile, farther south than 
that of the red-necked phalarope. The species has been seen on the 
other side of South America up the River Plate, and probably in the 
Falkland Islands. 

On the west side of the Atlantic the situation seems really mysterious. 
Ludlow Griscom (1939) who has studied the migrations of both species 
off Cape Cod, Massachusetts, for a number of years, comments that 
more red-necked (northern) phalaropes use this route than grey (red) 
phalaropes. However, he has seen a thousand grey phalaropes in a 
day (19 April 1938), moving north at a time some weeks before the 
normal movement of red-necks. Up to a quarter of a million red- 
necks gather in early August between Eastport and Grand Manan 
in the Bay of Fundy, and flocks of a thousand or more arc occasionally 
seen off the Massachusetts coast. But farther south the phalaropes 
disappear into limbo; both species are recorded as far as Florida, 
and there are a few records of both on or near the north shore of the 
Gulf of Mexico. From the entire West Indies and the Caribbean Sea 
there is not one record of either species of phalarope. Do the W'est 
Atlantic phalaropes mainly winter off the New England coast ? 
Probably not. Do they only straggle farther south ? Or do they cross 
to West Mexico and pursue their way to western South America ? 
Or what ? 

In the open North Atlantic away from the coast phalaropes have 
been encountered at sea in many transects, notably those of Jespersen, 
Mayr, AVynne-Edwards, Rankin and Duffey. None of the observers 
has felt sure enough to decide which species he was observing, though 
it seems clear that at least some, if not all, were grey: the records have 
been plotted on the grey phalarope's map. The red-necked phalarope 
has been recorded once from Bermuda and once from the Azores, but 
otherwise was unknown from, the central and eastern Atlantic south 



Fig. 27 
Distribution of Phalaropus fulicarius, 
the grey (red) phalarope. Breeding 
area embraced by black line and 
shaded overland. Dots represent some 
sight or specimen records. Since the 
map was made Stanford (1953) has 
published more South Atlantic records 
off South Africa; and he believes there 
may be a wintering area off the Cape. 




Fig. 28 

Distribution of Phalaropus lobatus, the red- 
necked phalarope. Breeding area embraced 
by black line and shaded overland. Dots 
represent some sight or specimen records; 
that in Cape Province should be moved SE 
to Port Elizabeth. Fleming and others 
(1953) cite two New Zealand records. 




156 SEA-BIRDS 

of the Straits of Gibraltar until 17 March 1930, when from the research 
ship Dana A. V. Taning (1933) saw small flocks in a sea-area also 
occupied by grey phalaropes off the Rio de Oro coast of West Africa. 
But it is the grey phalarope (as P. F. Holmes (1939) particularly shows) 
that appears to have a regular wintering area off the coast of sub- 
tropical and tropical ^Vest Africa, from Madeira and the Canaries 
to the Cape Verde Islands and beyond; indeed some elements clearly 
carry on to the Cape in South Africa, probably via the Gulf of Guinea 
and the Cameroons; there are a few inland records in South Africa. 
The remaining sea-area known to be inhabited by the two phal- 
aropes in the winter is that part of the Indian Ocean that stretches 
from the Gulf of Aden to north-west India, and which includes the 
entrances of the Red Sea and the Persian Gulf. This concentration of 
phalaropes is discussed by R. Meinertzhagen (1935) and several 
others: probably both species approach it from the Eurasian arctic 
breeding-grounds mostly overland; the records of red-necks suggest 
so, though some elements of both species pass through the Mediter- 
ranean. However, neither has yet been recorded from Egypt. 



CHAPTER 6 

NAVIGATION BY SEA-BIRDS 



WE HAVE SEEN sca-birds, especially the tubenoses^ in the Atlantic 
many hundreds, often well over a thousand miles, from the nearest 
continent, and sometimes several thousand miles from their breeding- 
grounds. As the open sea to a man without instruments of navigation 
is a seemingly trackless desert, we marv^el at the ability of the sea-bird 
to fly home to a remote island or cliff many weeks' journey from its 
wintering grounds. Thus the arctic tern crosses almost from pole to 
pole, from the Antarctic to Greenland. The great and sooty shear- 
waters breed on islands in the extreme South Atlantic bordering the 
Antarctic, but winter in the North Atlantic (thus enjoying perpetual 
summer) as far as the east coast of North America, Greenland, Iceland 
and the west coast of Europe. Wilson's petrel, breeding along the edge 
of the Antarctic Continent, performs one of the longest migrations 
known, one of about 7,000 miles each way. During most of this journey 
from the south polar sea to the Newfoundland Banks or to the Bay 
of Biscay or the seas between, it may never see the land, yet this small 
fragile-looking bird is able to return to the same nesting hole and mate 
at approximately the same date each year of its adult life. It may be 
argued that if W^ilson's petrel continued to fly south it would be bound 
to strike the Antarctic Continent and so have a landmark to guide it to 
its breeding island or shore in the nearby seas. But how does the great 
shearwater, breeding exclusively on the Tristan da Cunha islands, 
and migrating six thousand miles northwards in the southern winter, 
find its home islands, which are 1,500 miles from the nearest land, 
whence, as Wynne-Edwards points out, they subtend an arc of only 
15 minutes. It is possible that Tristan normally provides a bigger 
target than that, for it projects some thousands of feet into the sky 
and for most of the time produces a cloud-mass which is high and 
spreads for many miles. And it is possible that great oceanic islands, 
such as Tristan, even if their actual area is fairly small, may produce 



158 SEA-BIRDS 

minute changes in the surface and topography of the sea which may 
be detectable many scores of miles away by birds. 

Many experiments have been made with sea-birds with the object 
of discovering the physical nature of the mechanism of homing birds. 
Visual memory can serve where there are familiar land or sea marks, 
and birds experimentally released within sight of these do orientate 
themselves and fly home very quickly. But where they successfully 
return when released far from home and in country or upon seas which 
they are presumed never to have visited before, visual memory as an 
aid is out of the question. The classical experiments with noddy and 
sooty terns carried out by Watson and Lashley (19 15) are well known. 
Breeding adults from the Tortugas Islands, Gulf of Mexico, were sent 
by ship for distances of more than 850 miles, and returned from points 
far to the north of their normal distributional range. Griffin sum- 
marised these and other homing experiments which included terns, 
gulls, petrels and shearwaters; he concluded that some birds return 
home by a process of exploration in search of familiar visual landmarks. 
A gull released over the land and followed in an airplane flew at 
random until it sighted the ocean, towards which it then headed 
directly, although this particular part of the sea was neither the 
nearest salt water to the point of release nor the direction in which 
its nesting ground lay. Griffin and Hock (1948) took gannets from 
Bonaventure in the Gulf of St. Lawrence, released them over a hundred 
miles from the coast and followed them by air, sometimes for more 
than a hundred miles. The paths taken by the birds consisted of fairly 
long "legs" with sudden sharp turns, and somewhat resembled a 
cubist's idea of a spiral search, though the most simple explanation 
of this search is that it was quite at random. About sixty per cent, 
of the gannets released eventually reached home at a speed of about a 
hundred miles a day; those followed by air homed equally with a 
group of control birds that were not followed. 

Two Manx shearwaters which returned to Skokholm after release 
at Venice have provided an early example of a sea-bird returning 
from an almost land-locked sea which it never normally visits (Lockley, 
1942). A significant fact about this release was that one of the shear- 
waters, instead of heading for the open sea (Venice is 3,700 miles by 
sea from Skokholm, and a bird taking the sea-route would have to 
begin by flying in a direction directly opposite to that of Skokholm) , 
rose up into the air and flew inland westwards in the direction of the 
sun, which was at that moment sinking behind the Italian Alps! 



NAVIGATION BY SEA-BIRDS I59 

By airline Venice is only 930 miles from Skokholm; and one bird 
got back in 14 days. At the time of this experiment this instantaneous 
correct orientation on release in fine weather was regarded as remark- 
able, but thought to be accidental; as were also the correct orientations 
of some other shearwaters released in the Alps. However the latest 
work by G. V. T. Matthews with shearwaters from Skokholm has 
confirmed that there is an immediate initial orientation of this species 
when released inland in fine weather; returns to Skokholm were at 
high speed (from Cambridge, 230 land miles in 6|, 8, 8, and 8J hours, 
from Birmingham, 156 miles and London, 225 miles, in 17J hours). 
In heavily overcast weather birds released at Cambridge showed an 
initial random scatter and none returned until the third night 
(Matthews, 1952). Finally the latest shearwater test by Dr. Matthews, 
arranged by one of the writers, has created a world record for a ringed 
bird used in a homing experiment. A Skokholm shearwater, conveyed 
by our friend Rosario Mazzeo to Boston by air and released on 3 
June 1952 at the edge of the airport which fringes the sea there, 
returned to its nest burrow at Skokholm on 1 6 June. It covered the 
3,200 (land) miles across the Atlantic in 12 J days, thus averaging 
250 miles a day, or more than 10 miles an hour. Even swallows 
(128 miles a day) and terns (139 miles a day) used in earlier tests have 
not equalled this speed. For a reason which is discussed below it is 
possible that this Boston-Skokholm shearwater may not have travelled 
at night; in any case we must allow it at least four hours average a 
day for feeding, preening and resting, and we must also allow for time 
lost as a result of its normal swinging deviating flight which makes 
its surface speed probably a third less than its flight-speed. It is clear 
that this bird had not time to spare for random searching, and yet 
the Manx shearwater does not visit the North American coast except 
as a very rare straggler. It was a fine clear morning when it was released 
at Boston and it immediatly flew eastwards in the direction of the open 
Atlantic — and Skokholm. This initial correct orientation cannot be 
explained satisfactorily by stating that it was accidental, or that a 
sea-bird would naturally fly away from the land; our shearwater at 
Venice turned inland towards high mountains, and Matthews' shear- 
waters in London and Cambridge flew at first further inland (in order 
to reach Skokholm quickly) rather than eastwards to the nearest sea. 
Initial orientation almost (in some instances quite) on the right com- 
pass bearing in fine weathei' and unknown territory can only be 
explained by the possession by the shearwater of an orientation 



l6o SEA-BIRDS 

mechanism which is quite independent of topographical '^knowledge' 
or memory; and the fact that the mechanism breaks down in 
cloudy weather suggests very strongly that orientation is by the sun. 
Kramer (1952) found that the highly accurate orientation faculty 
in his caged starlings vanished if the sun was hidden: when tests were 
made with an artificial sun (lamp) indoors, they orientated as if the 
lamp were the sun. 

The sun-navigation theory, while it disposes of earlier hypotheses 
of kinaesthetic memory and sensitivity to the earth's magnetic field 
or Corioli's force (which depends on the velocity of movement of 
points on the. earth's surface relative to its axis and which therefore 
varies with latitude), does not explain night-migration, which is a 
well-known phenomenon, although not commonly reported of sea-birds. 
Most sea-birds in fact rest at night, either on land or sea. The activity 
of fulmars, watched by us from a trawler, showed considerable diminu- 
ution at night. Manx and other shearwaters assemble in rafts on the 
sea in sight of their breeding-grounds before sunset, although they 
often do not land until two hours after sunset. In heavy overcast 
conditions many night-migrants appear confused and may descend 
in their greatest numbers on the coastal bird observatories, there to 
rest — and this is sometimes erroneously referred to as a "good migra- 
tion." But it is on clear moonlit nights that the best migration occurs — 
at least for the migrants, which can navigate onwards without a halt, 
and without striking the lanterns of lighthouses, because they see the 
outlines of the land and the astronomical signs clearly. 

Sun or astronomical navigation seems to be the most satisfactory 
explanation so far; and more research into night-migration may 
reveal that the migrant is guided by moon, stars, pre-glow and after- 
glow which may assist it to keep on a course already begun before the 
sun or its glow has left the sky. It should be remembered that night- 
migrants only fly for a comparatively short period, for not more than 
half the night — unless they are caught, being land-birds, over the 
sea, when they must continue flying to the nearest land, often some 
cape or island where there may be a migration observation station. 
Research may also show that the sea-bird is more lost and helpless 
in misty weather than was formerly believed; and that stories of 
homing through dense fog are largely fictitious. Sea-birds are in fact 
confused in heavy mist, and are then easily caught at the nest by the 
use of a powerful torch; on such nights shearwaters will accidentally 
strike objects over the breeding ground during flight, including light- 




Fig. 29 

Breeding distribution of the Manx shearwater species (or superspecies) 

Puffinus pitffinus. P.p. yelkouan also nests on the island Riou, near Marseilles ; 

and P.p. gania as far far south as Cook Strait. 



M 



l62 SEA-BIRDS 

houses, rocks, and the observer himself — but never on fairly clear or 
clear nights. 

The Manx shearwater is loudest and most vociferous at its breeding 
island on dark nights and when there is dense mist. This, we believe, 
is partly explained by the fact that the incoming bird, unable to 
recognise immediately the environment of its burrow in thick weather, 
screams almost continuously so as to attract a response from its mate 
on duty in the burrow, who answers and so guides the arriving bird. 
Glauert (1946) believes this to be the explanation in the case of the 
little shearwater {Puffinus assimilis), in Western Australia where on 
Eclipse Island these birds called loudly on dark nights and almost 
not at all on moonlit nights. There was the same amount of activity 
under both conditions; the little shearwater on Eclipse Island has no 
predatory enemies. But on other islands where adult shearwaters and 
petrels are slain by resident gulls and hawks and owls * there is notably 
less activity on fine clear nights, as well as almost complete silence 
from the few incoming birds. Obviously if the mate of the bird is 
already at the nest and answers the cry of the homecoming bird on 
a dark night there is direct guidance. But why should the incoming 
bird scream on a dark night, when (e.g. early in the season) there is 
no mate to reply? We put forward the suggestion, cautiously and 
merely as a possible line of investigation: that just as some animals 
(e.g. bats) are extremely sensitive to the echoes of sound-waves and are 
able to judge accurately the short distance they are in flight from 
objects they cannot see; so the homing sea-bird, on a dark night, 
may do so by receiving back from the rocks and cliffs and uneven surface 
of the breeding-ground echoes, perhaps of its voice"]" even its own 
wing-beats. 

To return to long-distance homing and migration, it would now 
appear that the tubenoses navigate great distances over the sea with 
the aid of the sun and a time-sense which enables them to compensate 
for the diurnal movement of the sun; as well as, after crossing the 
Equator at the equinox, a return to early summer. Having once 
made the annual migration both ways (we have referred to an arctic 
tern, ringed as a juvenile 8 July 1951 in the Christianshab district of 
West Greenland which travelled over eleven thousand miles across 

* At Skokholm and Skomer little owls prey upon storm-petrels. 

t As this book lay in page-proof we heard of the successful proof by D. R. Griffin 
and W. H. Phelps Jr. that the oil-bird Steatornis caripensis of the Venezuela caves 
navigates in darkness by echo-sounding, like bats. 



NAVIGATION BY SEA-BIRDS 163 

the Equator and was recovered at Durban, Natal, on 30 October 1951 
— average rate, about 100 miles a day for 114 days!), the individual 
has presumably become acquainted with what is, to man, an almost 
trackless route. As to the young non-breeding adult of over a year old 
it will presumably have the older more experienced adults to travel 
with. Rowan (1952) suggests that great shearwaters form rafts on the 
sea close to the breeding islands at the end of the season in preparation 
for departure in flocks for the northerly migration. But what of the 
fledgeling of those species such as the petrels and the puffins, which is 
deserted by its parents a week or two before it leaves the land, and 
travels solitarily to the sea? It may be observed making its way alone 
into the ocean up to fifty miles or so from the breeding-ground, as 
we have ourselves recorded. What happens to it in the next few days 
no one seems to have observed accurately, but it can receive no guid- 
ance from the adults in those early weeks — they are far at sea, and in 
moult. Probably, like the fledgeling gannet, it soon overtakes the 
adult flocks or at least passes through their extended wintering range, 
and, guided by an instinctive orientation, proceeds to a nursery or 
wintering-ground of juveniles, perhaps hundreds of miles beyond 
that of the adults. We would cite the case of a Manx shearwater, 
ringed as a juvenile at Skokholm on 10 September 1951, which was 
reported from Rio de Janeiro on 20 November 1951, thus confirming 
what we had long suspected: that the Manx shearwaters which are 
known to visit South America include young birds from Europe. 
This particular juvenile had covered 5,050 nautical miles in a maximum 
of 71 days (which is 71 miles a day), a striking performance for so 
young a bird. Another ringed Manx shearwater has been recovered 
in the South Atlantic; an adult marked on Skokholm in July 1947 
reached a point 200 miles south of Buenos Aires in the autumn of 1952. 
So the old shearwaters can migrate as far south as the young ones. 
But the concentration of fulmars on the Newfoundland Banks, about 
fifteen hundred miles from the nearest breeding station, may be a 
young fulmar nursery. Fisher (1952) shows that the four marked birds 
recovered there were all first year (juvenile) birds, two from Greenland 
and two from St. Kilda. 

This must be a short chapter, because our knowledge of the mech- 
anism of orientation is so limited. To sum up: it seems that sea-birds 
may navigate like human beings do at sea. Although without mech- 
anical aids, they find their way by learning the chart; by knowing 
the time (it is becoming clear that most birds have an accurate time- 



164 SEA-BIRDS 

sense) ; by dead reckoning, probably in terms of flying-time rather 
than distance covered; by observing the sun and stars and their position 
in relation to the horizon. They may exploit other signs, such as the 
set of the currents, temperatures, and the presence of animals of their 
own or other kinds. We know that birds can make the mistakes that 
human navigators make, such as getting adrift and wrecked. And 
we know that they can, by instinctive orientation and navigation, 
without instruments, do things that humans cannot do. 
That is the present state of our knowledge. 



CHAPTER 7 

SOCIAL AND SEXUAL BEHAVIOUR 



BEFORE WE describe their exciting and varied life-histories we ought 
to review the present state of our knowledge of the social and 
sexual behaviour of sea-birds, from which a general pattern emerges 
which enables us to understand the meaning of their fascinating, 
and often very peculiar, specific ceremonies and displays. 

After normal 'maintenance activities' (as they have to be called) 
the life of the sea-bird is centred round its reproduction, without 
which the species cannot continue. From these two activities all 
sociality (gregariousness, flocking or living together) arises; and sexual 
behaviour is the most important aspect of social behaviour. 

Pair-formation requires the location of a partner, the attainment 
of which in the first place involves the breaking down of certain 
safeguards and habits with which the individual protects itself during 
the non-breeding period, and the establishment of a state of intimacy 
between male and female. The mechanism or behaviour by which 
the individual ring-fence is maintained on the one hand, and by which 
it is altered in order to secure the sexual bond on the other hand, is 
a remarkable phenomenon, popularly known as display. 

In sea-birds, which are monogamous, display is mutual. The 
unilateral display and courtship behaviour of polygamous land-birds 
(such as the ruff, blackcock and jungle-fowl) hardly concerns this 
chapter as comparative material. Polygamy is usually associated 
with a brief but brilliant display or tournament between conspicuously 
adorned males, which, after mating, leave all the work of incubation 
and brooding to the dull-coloured females. The polygamist is an egoist 
occupied solely with the three m's: mating, moulting and maintenance. 
The male sea-bird, a monogamist, is by human standards a model 
husband, taking equal responsibility with his mate for nest-making, 
incubation, and rearing duties. Darwin (1871) overlooked the signi- 
ficance of mutual display when promulgating his theory of sexual 



1 66 SEA-BIRDS 

selection; it was Selous (1905, 1905-06) who pioneered the general 
concept of unilateral versus mutual display, to be followed by Huxley 
(1914) who, with his papers on the striking courtship of the great 
crested grebe, introduced its importance to professional biology. 

The mutual ceremonies of the sea-birds are hardly less remarkable 
than those of the grebes. They are prolonged throughout the summer, 
long after mating has taken place and the young have hatched, but 
their function is a useful one: mutual display serv^es as an emotional 
bond to keep the monogamous pair united so long as parental cares 
continue. This interesting biological device is of course of no value 
to the polygamous land-birds, in which the male takes absolutely 
no interest in the family. It is evident, then, that the relation of the 
sexes to the young and to each other determines the type of courtship 
display as well as the degree of development of the external sexual 
characters (colour and plumage) in male and female. Sexually faithful 
husbands resemble their wives so closely as a rule that the observer 
often cannot distinguish between the sexes of sea-birds in the field — 
for even the act of coition is sometimes reversed. Mutual display — 
leading to mutual stimulation — is advantageous where there is such 
outward uniformity. 

It is interesting to trace the origins of sexual display. In courtship 
all sea-birds make use of the bill in rubbing, fencing, scissorsing, 
fondling or preening motions; in doing so they are unconsciously 
copying the familiar movements of feeding and being fed as chicks. 
Gaping is a characteristic of some sea-bird courtship ; it too is derived 
from gaping when being fed in the nest. Threat attitudes, involving 
the use of the bill, the raising of neck-feathers, and often wing-play, 
can be traced to the behaviour of the growing chick when it first 
defends itself from its nest-mates (as when securing food at feeding- 
time) or other rivals or enemies; these threat attitudes become incorp- 
orated in, or adapted to, the courtship display. 

How early in its existence the young sea-bird receives the first 
mdelible impressions of the voice and behaviour, including the mutual 
display, of its parents we do not know — probably the precocious gull, 
tern and skua chick does so as soon as it hatches. Lorenz (1935) has 
shown that by taking the place and duties of the parent wild goose at 
the moment of hatching he transferred to himself the allegiance of the 
gosling, including its responses of sexual behaviour which develop at 
the appropriate age. This imprinting of parental influence is the 
first step in the socialising of the chick, which proceeds rapidly during 



SOCIAL AND SEXUAL BEHAVIOUR iG/ 

the close contact of the rearing period as it receives affection, protection, 
and guidance from the aduk. Every action of feeding and preening 
of the young by the parents strengthens the family (social) bond — 
an experience to be of value later in the bird's life. The chick learns 
to associate food and protection with others of its kind. Gradually 
it learns to recognise individuals, first of all, its parents; although it 
may not distinguish their sex at this stage it probably recognises them 
as individuals by their individual behaviour, as for example when the 
male gull feeds the female who in turn feeds the chick. 

So far it has learned to associate its parent's bill with the pleasant 
sensations of feeding and grooming. How does it acquire knowledge 
of danger, for soon it must learn that only its parents are not its 
enemies? Danger is usually indicated by the warning-notes and 
flight-actions of the adult, the chick's response to which seems to be 
at first due to instinct, or maturation of instinct, rather than to any 
process of learning. Young gulls, though precocious and born with 
their eyes open and able to walk, do not crouch or hide on a warning 
signal until they are two or three days old. Young gannets, born 
blind and naked and with a more embryonic brain than the gull 
chick, do not strike at intruders (when, with warning cries, the adults 
leave the nest) until their eyes are open and they are covered with 
the first down. As the brain develops however, learning is mingled 
with maturation of instinct, and adaptability to new situations is 
acquired. 

At fledging time the young sea-bird discovers that its parents are 
growing indifferent to its food-begging advances, and wdll ultimately 
repulse them, or will abandon the chick completely (tubenoses, 
gannets and puffins). In some species of social gulls the adults not 
only become hostile but, unless the young bird retreats, will actively 
attack and kill it. Thus sociality, which is not proved to be innate 
(no hormone for gregariousness has been demonstrated in studies 
of the endocrine organ of a bird), receives its first serious check, and 
the family bond is broken. To minimise the attacks of the adults the 
juvenile sea-bird learns to keep at least one body's length (striking 
distance) from a neighbour; and a pattern of behaviour is acquired 
which enables the bird not only to retreat at the aggressive display 
of the adult, but to employ the same threat signals to drive away 
birds younger or weaker than itself. By this device — usually a lowering 
of the head, pointing of the bill (mouth sometimes open) and raising 
of the neck- feathers — it is able to take its place in the community. 



Fig. 30 
Distribution of sight and specimen records of Wilson's 
petrel, OceaniUs oceanicus, replotted from B.B. Roberts 
(1940). Inset, breeding distribution ; dots here represent 
some known breeding stations. A recent paper of Murphy 
and Snyder {1952) indicates that magellanicus should 
probably be united under parvus and exasperatus under 
oceanicus. 




170 SEA-BIRDS 

Threat display in fact is now a very important part of the behaviour 
of the newly independent bird if it is to secure an advantageous 
position in the winter flock. In the congregations of gulls which feed 
in farm fields, at rubbish-tips, by sewers, rivers and harbours, and 
which roost on reservoirs and islands, there is, as in domestic hens, 
a definite order of precedence, or peck-right, and the flock is so 
organised that the most dominant bird takes up the best feeding or 
roosting position, and maintains it by threat actions. In this hierarchy 
the inexperienced juvenile usually has a low initial status, as in com- 
munities of men. It will move towards the centre as it grows stronger 
and more experienced. Some flocks are however composed entirely of 
juveniles, as those of some gannets, shearwaters, petrels, and puffins 
which, deserted by their parents before leaving the breeding ground, 
perform long migrations, and gather at wintering grounds beyond the 
range of the adults. Little is known of the construction of pelagic 
flocks ; probably a form of precedence is built up in the same way, 
both specifically and inter-specifically, in the wide-ranging tube- 
noses, skuas, terns, and gannets, pelicans, and auks when they become 
concentrated at rich fishing grounds. We have watched great shear- 
waters displaying at fulmars in disputing fish-offal at the side of a 
trawler at Rockall, and fulmar dominated fulmar in the same scramble 
for food, using the ^characteristic threat display of lowered head, 
opened wings and cackling noises. 

When the young sea-bird, stimulated by the seasonal development 
of its breeding organs, returns to the nesting ground for the first time, 
it has now to overcome two obstacles: the barrier of "individual 
distance" by which it maintained its position in the flock, and the 
difficulty of procuring a mate of the opposite sex — if it is to breed 
successfully. These obstacles are so formidable that the inexperienced 
bird may never overcome them in the summer of its first return to the 
land. Its behaviour may remain appetitive, never reaching the stage 
of consummation: it arrives, establishes or enters a territory, displays 
and flirts with a bird of the opposite sex, but never copulates (or it 
copulates too late to breed successfully). However this behaviour is 
not without its function: from this experience it will be better equipped 
to initiate successful breeding in succeeding years. 

The male (terns and gulls) is usually the first to arrive at the 
breeding ground, or at least to occupy a prospective nest-site or 
pre-territory. He calls loudly as if seeking to attract a partner. But at 
first he behaves aggressively towards any bird, male or female, which 



SOCIAL AND SEXUAL BEHAVIOUR I71 

responds; he uses the threat display — the only social behaviour or 
reaction he is, by use, familiar with. As the sexes are so alike it has 
been suggested that, if he is inexperienced and attempting to breed 
for the first time, the male may not know the sex of the responding 
bird, but must find out by a closer acquaintance, by trial and error. 
His behaviour suggests this: the male tern or gull threatens, even 
attacks, the newcomer. If the arrival is male he will fly away or 
engage in a dispute for the territory; if female she will stay, and by 
her refusal to fight indicate her readiness to pair. She may remain 
quietly near him, watching his threat display, or responding with 
similar movements, but without being aggressive. Her behaviour 
acts as a releaser or signal that elicits the beginning of the love-bond. 
Threat-display wanes in favour of mutual attitudes of appeasement, 
expressed by turning away (upwards or aside) the conspicuous bill 
and head (gannets, cormorants, gulls, terns, skuas, auks). Sex-recog- 
nition has taken place, and with it begins mate-recognition. 

In the love-ceremonies that follow the barrier of individual distance 
is gradually broken down. Yet although the head, with all its apparatus 
of intimidation — coloured bill and gape, facial adornments, raised 
neck-feathers, is turned away in the appeasing movements, in order 
to become intimate the bills, and in order to copulate the bodies, 
must be brought together. The female gull, skua and tern indulge 
in a food-begging ceremony in which she crouches in a supplicatory 
attitude before the male, her bill towards his, her mouth open, thus 
unconsciously imitating her behaviour as a chick. Females of other 
species — gannets, cormorants, tubenoses and auks — touch bills with 
their males in head-shaking, scissoring, and clashing movements, 
ceremonies likewise derived from the chick stage. Stimulating contact 
has been made, and soon coition follows, usually in the nest, and the 
barrier between female and male temporarily disappears. The mated 
pair now stand or sit (or fly) side by side. The male of the more mobile 
species (gull, skua, tern, puffin) establishes a somewhat larger "mated 
female distance" or sexual territory around his mate and the nest-site, 
from which he drives away or intimidates all other males. For this 
purpose the familiar threat display is used. She will also attack — other 
females. On their territory the pair are invincible; moral right is 
stronger than physical might in defence of the home. 

After pairing the love-ceremonies do not cease. The establishment 
of the family bond is imperative if the young are to be reared by joint 
effort. The pleasurable ceremonies are continued after coition has 



172 SEA-BIRDS 

ceased, and throughout incubation and rearing. Gannets clash bills, 
puffins rub beaks, shearwaters yodel and interlock bills, gulls and terns 
beg for food, throughout the summer, until at last the urge wanes 
with the fledging of the young and the onset of the moult and migration. 
Mutual display late in the season may be of a playful or recreational 
significance, an outlet for surplus energy. 

There are other interesting, and some quaint, ceremonies. Thus at 
the nest relief, after the greeting display of billing and harsh cries is 
over, gulls and gannets will add material to the nest if prevented 
from brooding by the refusal of a mate to leave the eggs. This is a 
'displacement activity', and it takes various forms. All nest-making 
sea-birds toy with material, placing it over the shoulder, or throwing 
it in the air and even swallowing it (gannets and gulls), while puffins, 
which do not make more than a slight lining to the nest (sometimes 
no lining), aimlessly pick up, carry and drop grass, feathers and stones. 

Does mate-recognition last for more than one summer, that is to 
say, do sea-birds pair for life? By his behaviour and voice the mature 
female recognises a male calling her to a nest-site; by his voice and his 
occupation of the familiar nest-site she probably finds the identical 
mate of last spring. To that extent the monogamic sea-birds may be 
said to be faithful so long as both shall live; proof has been forthcoming 
in recent studies of ringed shearwaters, penguins, guillemots and 
razorbills. Even so, before the love-bond is re-affirmed in the spring 
the same ritual of threat — followed by appeasement — gestures is 
carried out; just as it is, in more or less degree, at every reunion of the 
pair at the nest throughout the summer. Yet the sequence now is 
bivalent — it has become less a display serving its original purposes 
than a ritualised greeting between mated pairs. Elements of two main 
drives in the life of the bird can be detected in the love-ceremonies: 
thus the frenzied billing of gannets and nose-rubbing of puffins seem 
to exhibit something of the desires of both self-preservation and 
reproduction inextricably mixed. Fighting and love-making behaviour 
are nearly akin, as hate is to love; both are highly stimulating. The 
winter habit of keeping at a safe distance from a neighbour seems to 
be latent in every sea-bird, and the arrival of even its mate at the nest 
tests the nervous organisation of a bird severely, so that its first reactions 
may be mixed, with the self-preservation drive on top. This is demon- 
strated by the actions of a herring-gull if its mate's return is sudden — 
according to the mood of the bird at home it may move away or attack, 
until full recognition occurs and the ceremonies of greeting take place. 



SOCIAL AND SEXUAL BEHAVIOUR I73 

The opening of wings alerts a neighbour or partner; in the herring- 
gull this action releases the attack drive, and it may stab at its mate's 
wings, or even its own. Even when recognition takes place at a distance 
(gulls and puffins can recognise their mates by sight ten metres away, 
either in the air or on the ground) display takes place as the pair come 
together. Often the untoward movement of one of the partners as the pair 
sit or stand near the nest will start the other, or neighbours, displaying 
or calling or both. Any movement within the colony is stimulating. 
This stimulation, relating as it does to numbers, brings us to 
consider the relations of the individual, and the pair to the breeding 
flock, and what advantages there are in social nesting. Perhaps the 
first thing to note is what determines the density of the breeding flock. 
In spite of the availability of apparently suitable territory near by, 
the social sea-birds prefer to crowd together in a specific and fixed 
density pattern. As examples, gannets, increasing from 60 to 16,000 
breeding adults in less than one hundred years at Grassholm, Wales, 
have never varied the positioning of their nests one yard apart, and 
today they occupy only two of the twenty-two acres of ground suitable 
for expansion; and guillemots, which formerly occupied completely 
a wide ledge two or three hundred yards long on the neighbouring 
island of Skomer, as they decreased in recent years, instead of spreading 
out thinly over the ancient breeding ledge continued to crowd together, 
leaving large gaps which have become grown over with the nitrogen- 
loving chickweed. The innate sociality of sea-birds is such that a 
diminishing colony contracts towards the centre in the same fixed 
pattern that an increasing colony expands; and the pattern is deter- 
mined by the minimum territorial requirements of the breeding 
pair — in the gannet a three feet radius from the nest-centre, in the 
guillemot about twelve inches between each brooding bird. The 
attraction towards the centre of population (evidence of sociality 
in its highest form) is not unique to sea-birds ; it is a protective device, 
common to many social animals. The breeding flock is composed of 
a core of old adults in the best positions at the centre, surrounded by 
a bulk of middle-aged members, and an outer skin of inexperienced 
young birds. The greatest mortality occurs at the perimeters where 
the young birds, detached, inexperienced, often wandering solitarily 
and far on migrations, are most exposed to outside dangers. Until 
they return and begin moving in towards the centre, they do not 
become units in the main flock; but once they have re-established 
themselves in the flock they will continue year by year moving towards 



ly^ SEA-BIRDS 

the centre as the old birds die and leave vacant places. In the centre 
lies the greatest safety for the individual. 

The smaller the flock the greater the exposure of the individual 
to peripheral dangers until, when a colony of only one or two pairs 
is reached, the core is wide open to those dangers. Conversely there 
is protection in numbers — and there is also stimulation. It is well 
known that in certain species (the budgerigar is quoted as a classic 
example) two or three pairs together breed and produce more young 
per adult than one pair breeding alone. Darling has suggested that 
there is a threshold below which a social species breeds irregularly 
or fails to breed, although he admits that this concept must be applied 
warily, since the numerical threshold varies with the environmental 
complex. Stimulation and protection in breeding by isolated pairs of 
a social sea-bird may, however, come from related or unrelated 
species using the same breeding ground; thus two pairs of gannets 
have bred successfully for many years, although without increasing 
their breeding numbers there, in the centre of a large colony of guille- 
mots (Saltee Islands) ; and the reverse is recorded — a few pairs of 
guillemots breeding successfully within a large colony of gannets 
(Grassholm, and also Alderney). It is generally accepted that small 
colonies of guillemots and razorbills, gulls and other sea-birds produce 
fewer young per head of breeding adult than large colonies. It has 
been suggested that this may be because small colonies are composed 
of younger birds ; if this were invariably so then it would argue that 
individuals, as they grow older, move from the small colonies to the 
large! This, however, is not the case; we have known small colonies of 
shearwaters, and of guillemots and razorbills at Skokholm which have 
existed for decades (within a few hundred yards or less of large colonies) 
with their hard core of old ringed breeders. Their breeding success has 
been variable, fair in the shearwaters, poor in the guillemots; but 
habit compels them to stick to the old site, whatever the success. 
Single pairs of guillemots and razorbills have generally had no breed- 
ing success. It is true however that small new colonies of sea-birds 
are invariably composed of young birds, which are always the colonists, 
and they take several years (and sometimes fail in the end) to build 
up a permanent breeding core. The fulmars which are spreading to 
new sites in western Europe are probably all young birds which have 
not bred before; also, for years Great Saltee Island was visited by 
immature Manx shearwaters before breeding took place there recently. 
How does the advantageous stimulation of the large flock work? 



SOCIAL AND SEXUAL BEHAVIOUR 1 75 

When in a flock a sentinel bird sees an enemy and flees, or flies to 
attack it, the rest of the flock instantly heed the signal (a cry of warning, 
a display of wing or tail pattern, or merely the opening of the wings, 
or all of these signs together), and they too rise in the air. Thus a 
mood of uniform alertness is elicited in every member of the flock at 
the first notice of danger, and this is an advantage of numbers which 
has obvious survival value. So swift is the bird's reaction to warning 
and other signals that the flock may appear to act wdth complete 
synchronisation; but the mood is not really instantaneous, it is acquired 
by each bird individually copying another, and in the largest flocks 
the mood is seen to pass through the birds in a wave. 

So-called synchronised flights also occur for no apparent reason, 
initiated in the same way by a leader or dominant or nervous bird, 
such as the "dreads" and panic flights of terns. Other combined 
operations, such as the joy-wheels of puffins and other auks, the mass 
diving of guillemots, the nocturnal circling flights of petrels, and the 
summer assemblies of gulls and oyster-catchers in favourite spots 
away from the nesting sites, seem to have a sexual significance. They 
may be caused by a temporary re-assertion of the flocking instinct 
(Tinbergen, 1951); their function seems to be that of sustaining a 
high emotive tone, for they are set in motion by the most exuberant 
individual in the flock, whose example and mood is so infectious that 
it is rapidly mimicked by the whole community. Herring-gulls will 
automatically preen in unison, copying a leader, as sub-consciously 
as man may copy another man yawning. 

In a colony of sea-birds the most mature adults are the first to 
take up territory and breed in the spring; their display and pre- 
coitional activities set the pace for the less mature members of the 
community. Their example acts as a stimulus, with psychological 
and physiological effect on their neighbours; their first matings 
promote the hormonic development and the ripening of ova in neigh- 
bouring pairs. Their mood elicits a like mood in the others, and the 
sexual rhythm of the whole colony is quickened as the emotive tone 
rises. Occasionally, if their females are not ready, the stimulated males 
may even attempt adulterous matings (gulls, puffins, albatrosses). 
Usually however, the males are occupied in inducing their own mates 
to copulate within the nest-site territory, and their display and 
behaviour has the efifect of synchronising the female sexual rhythm 
with theirs. All this intensive stimulation results in earlier and more 
uniform breeding in the large flock. 



176 SEA-BIRDS 

The advantages are obvious: the shorter the period of exposure 
of the eggs and chicks to possible predators the better the chance of 
survival. On the question of predation, however, we should note 
that the individual in the large flock is not necessarily able to defend 
itself better than the individual in the small flock, except that quanti- 
tatively the individual is safer in the crowd. Although sea-birds are 
sociable they are ^essentially selfish and non-co-operative outside the 
family circle; tales of flocks of sea-birds attacking an enemy in forma- 
tion must be discredited. At most single or a pair of skuas, terns or 
gulls will mob an intruder, and only provided it is trespassing near 
their nests; skuas will also employ the broken- wing trick (injury- 
feigning) to lure an enemy away. These two responses, as distraction 
displays, are only advantageous in species which are comparatively 
nimble on land and in the air, and which can easily escape from an 
enemy; they are entirely instinctive actions, but often have a successful 
result, especially in drawing mammals from the vicinity of the nest. 
But gannets, petrels and auks — birds clumsy on land — have no 
distraction display; when threatened by a predator they remain, at 
the best, prepared to do battle, or they take flight. Combined operations 
by sea-birds against a common enemy are quite unknown — otherwise 
man would not be able to show himself in a large sea-bird colony 
with no greater hurt than an occasional tap on the head, or a shirt 
soiled with droppings! However, large colonies of sea-birds are rarely 
established, and certainly cannot be maintained, except on isolated 
islands and in other situations where there is minimum interference 
from terrestrial enemies. 

To recapitulate, the advantage of the large breeding flock lies 
principally in social stimulation leading to synchronised breeding and 
so to an earlier and shorter and therefore more successful nesting 
season. This stimulation may have its source in the greater numbers 
of experienced breeders in the large flock. There is also the quantitative 
effect that the individual is safer from normal predation in a crowd; 
and there is greater alertness against attack because there are more 
individuals on the watch for enemies. 

Some of these advantages apply in the winter flock, which is 
principally engaged in the maintenance activities of feeding and safe- 
roosting; there are the protection and vigilance of numbers, and, 
besides, the advantage of many pairs of eyes discovering new sources 
of food supply. If food happens to be scarce the flock spreads far 
and wide in its search, but does not disintegrate completely. 



SOCIAL AND SEXUAL BEHAVIOUR I77 

Individuals keep within sight of each other and when food is found 
and the discoverer drops down and remains feeding for some time, 
the nearest birds quickly note this behaviour and are drawn to the 
food; in this way the whole flock becomes concentrated upon a rich 
supply until it is exhausted. The flock then disperses, resuming the 
widespread search for a new supply of food, but maintaining its 
former coherent but extended pattern. 



N 



CHAPTER 8 

THE TUBENOSES 



OF ALL THE BIRDS which frequciit the North Atlantic Ocean, the 
petrels or, as they are known today to ornithologists, the tube- 
noses, appear to be the most perfectly adapted to its frequent wild 
moods and heavy storms. A chapter on their life-histories would be 
incomplete, therefore, without a full discussion on the pelagic phases 
— little understood until recently — of the petrel's year. Only those 
who have seen from a ship at sea the fragile-looking storm-petrel or 
the long-winged shearwater or the more gull-like fulmar ride out a 
whole winter gale can realise, and admire and respect fully, this 
perfection of adaptation to the extreme conditions of environment. 
The more savage the gale, in fact, the more easily do these graceful 
birds seem to ride upon the salty air, and skim the heaving surface 
of the sea with more perfect mastery. Sustained by the winds, they 
are able to glide nearer to ships, and the human observer is able to 
study them. But formerly the superstitious mariner regarded the 
appearance of the small petrels close to the ship as an ill omen, accom- 
panied as they were by storms. 

The perfection of oceanic flight is seen best among the largest 
petrels, the true albatrosses, which, in the Atlantic, are confined 
principally to the southern hemisphere and rarely wander north of 
the equator. The structure of the very long slender wing of the alba- 
tross, with its long humeral bones and strong rigid primaries, makes 
normal wing-beating, such as that of the storm-petrel, difficult, and 
progression is almost entirely by gliding. The flight of the shearwater 
is similar. A considerable air-speed is a requisite of continuous gliding; 
albatrosses and shearwaters overtake, sail and soar around a fast- 
moving steamer without difficulty, and are seen to beat their wings 
seldom, and chiefly when, turning or mounting, they stall and lose 
momentum for a second or two. 

The observer sees that they are able to accompany a ship without 



THE TUBE-NOSES 1 79 

overtaking it too quickly only when it is steaming against the wind 
because their 'ground' speed is then reduced by the speed of the wind, 
but they move too fast when a ship is steaming with the wind and 
must then make a series of ellipses far out to port and starboard if they 
would keep with the ship. In calm weather these long-winged petrels 
manoeuvre in all directions and their true flight-speed, estimated to 
reach at least sixty miles an hour, is then more easily gauged. 

The flight track is always slightly curved, and although the 
albatross is seen to fly more often on a level keel than the smaller 
shearwater, both proceed by careering from side to side, rising up ten 
or twenty feet at the end of each movement to gain height (momentum 
is thereby lost) for the powerful downward plunge that shall carry 
the bird skimming at speed low over the surface of the sea. The observer 
sees first the dark back of the bird turned to him, and one wing-tip 
all but touching the crest or side or trough of the swell, then the bird 
rises, perhaps with one, or two, wing beats, swings slowly over, and 
presents the (usually) white belly to view as it glides gracefully onwards 
on the other tack. Once they have settled on a dead calm sea the 
albatrosses and the larger shearwaters have some difficulty in rising 
from the surface. When approached quickly in a boat, they flap 
awkwardly for a long distance over the surface, paddling with their 
legs, and may settle again without having got on the wing at all. If 
they are full fed they often lighten themselves by disgorging food. 
But in rough weather they easily launch themselves by opening their 
wings into the wind from the top of a wave, and are airborne immedi- 
ately. On land they need a long run to take off in fine weather if they 
cannot drop into the air from a cliff or high rock, or unless a strong 
wind is blowing. 

The ffight of the shorter-winged fulmars is similar, but the gliding 
periods are shorter, and turning and banking manoeuvres are achieved 
within a narrower compass, the wings being broader and the primaries 
rather more flexible than those of the albatrosses and shearwaters. 

Very different is the ffight at sea of the storm-petrels and frigate- 
petrels, which is best described as an erratic bat-like flitting, with 
brief intervals of gliding. It has been called swallow-like, but it lacks 
the directness of the swallow's flight, though it is almost as fast, and 
the wings are more expanded and the whole motion more light and 
wavering. In rough as in calm weather these little petrels follow the 
undulations of swell and wave, keeping within a few inches of the 
heaving surface, with an astonishing nicety. It is only when feeding 







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THE TUBE-NOSES l8l 

or searching for food that they hover, dropping their webbed feet to 
the surface, and paddHng upon it Hghtly as if walking, and sometimes 
diving for a moment. The word petrel (according to most dictionaries) 
is derived from St. Peter who walked the waves. The frigate- and 
Wilson's petrels use their long legs more often for this purpose and 
have an even more erratic flight. But these dainty petrels also dive 
well; we have seen storm-petrels at their best in wild weather off the 
Rockall Bank feeding and diving in the heavy swell. They would 
skim the marbled slopes of the sea, hesitate for a fraction of a second 
as they sighted food, then plunge under the surface for perhaps one, 
two or three seconds, scarcely folding their wings; and emerging 
with the same ease, wings swiftly spread, and every feather perfectly 
dry. Murphy (191 8) describes how Wilson's petrels dived to a depth 
of several times their length, leaping forth dry and light- winged from 
the water into the air. 

All tubenoses are good divers, but do not remain long under 
water or dive deep. Their food is obtained near or on the surface. 

The little shearwaters, which are intermediate in size between the 
storm-petrels and the Manx shearwater, have an intermediate flight 
described by P. R. Lowe as consisting of 'Tour or five beats and then 
a short glide and so on." 

There is no doubt but that the small sea-birds generally, and the 
petrels in particular, are able to help themselves in storms by avoiding 
those parts of the surface of the sea where the wind is most concentrated, 
that is, the crest of the wave or swell. They follow the trough of the 
wave, keeping closely to the windward slope where the water's surface 
is much less disturbed and there is a good upward air current to sustain 
them. B. Roberts (1940) repeatedly watched Wilson's petrel feeding 
and gliding on these windward slopes, but if the birds rose more than 
a few inches from the water they were instantly blown away downwind. 
It is when the storm shifts suddenly through 90° and blows parallel 
to the swell that small birds find no definite troughs in which to shelter, 
and so become exhausted by constant wing-beating over the confused 
water. As a result in changeable gales many are blown inland, or 
drowned and washed ashore. 

Roberts refers to the problem which has confronted all observers 
of pelagic birds — the inference that petrels in stormy latitudes have 
few opportunites to sleep or rest during the six months of continuous 
winter storms. But other birds apparently do without sleep for certain 
periods (as on migration), while immature swifts which in summer are 



l82 SEA-BIRDS 

seen to fly into the sky at dusk, do not return to roosting places: it 
now seems possible that these night-flying swifts doze or sleep on the 
wing. 

This, then, is the familiar picture of the petrels for the majority 
of people who only see these most pelagic of birds at sea. Able to 
sustain life in the stormiest zones farthest from land, and fitted to live 
without true sleep for days on the wing, the mysterious petrels have 
recently been the subject of intensive research on the remote islands 
where they breed. Their life histories are strange and interesting and 
many problems in them are unsolved. 

The old breeding birds are the first to return home in early spring, 
both because their reproductive organs are active before those of their 
young sons and daughters, and because they are experienced migrants 
familiar with the annual migration route. The urge to breed hastens 
their departure from the wintering area, an urge which in some species 
may prevent the older adults from reaching the extremity of that area, 
and fully mature birds may remain wdthin a day or so by air (say 
five hundred miles) of home throughout the winter. Once the adult 
tubenose has bred successfully it probably remains faithful to the same 
site for the rest of its life provided it can obtain a mate to share "home" 
with it. 

Territory (that is, nest-site-finding) is not therefore a novel or 
serious problem for the adult, which has only to occupy and defend 
the site already established in previous summers. To do this most 
successfully however it must return early, or the nest-site may be 
pirated by newcomers. Ringing has proved that both male and 
female petrel return to the familiar nest-site; and this is true for other 
sea-birds. 

This would suggest that petrels pair for life. If so, it may be asked, 
do they remain together on their migrations ? It may be significant, 
that, generally speaking, petrels are not usually seen in pairs at sea, but 
more often singly or in flocks. But Richdale (1950) is convinced that 
the royal albatross, Diomedea epoinophora, pair associate with each 
other at sea during the non-breeding year, and he proves that they 
return to the nesting area together. These albatrosses spend over 
a year in one breeding season and therefore have a short non-breeding 
year alternating with the over-long breeding season. Roberts and 
Lockley both consider that in the other petrels there is joint ownership 
of the nest-burrow or -site by a pair which meet there at the beginning 
of each season. There is no evidence among the smaller petrels and 



THE TUBE-NOSES 



183 




Fig. 32 
Breeding distribution of the storm- 
petrel, Hydrobates pelagicus 



shearwaters of any other lasting 
mutual bond, but, as mentioned 
in the previous chapter, because 
the pair meet and mate at the 
familiar focal point of the nest, so 
long as both shall live they remain 
faithful for life. This was found to 
be the case with a few exceptions 
over many years with the Manx 
shearwater and the storm-petrel, 
and over two years with the 
Wilson's petrel. 

Nest-occupation by all species of 
petrels begins well ahead of the 
laying of the single tgg. Thus ful- 
mars arrive in November and Dec- 
ember but do not lay until 5 May, normally not until after 12 May; 
Manx shearwaters first arrive in February but do not begin laying 
until the end of April; great shearwaters arrive in August and lay in 
November; storm-petrels come to land at the end of April and lay in 
June; Wilson's petrels are at least three weeks in preparing the nesting 
burrow while the winter snows have scarcely left the land; and the 
little shearwater in Western Australia apparently returns in January 
but does not lay until the end of June. The exceptionally early return 
of the fulmar and the little shearwater in the largest colonies may be 
fundamentally associated with the pressure of great numbers of ex- 
perienced adults in severe competition for the best nest sites; it is paral- 
leled in the case of other sociable birds, e.g. the common guillemot 
which returns (large colonies only) five months before laying begins. 
Where colonies are of a smaller size the return is correspondingly 
later in all these species, and many other sociable birds, including 
the fulmar (Fisher, 1952). Nest-site pressure, however (it should be 
added) is only one of many population-controlling factors. 

With the early return of the established breeders courtship activities 
begin. They are not at first either prolonged or passionate but rather 
preliminary. The Manx and little shearwaters and the fulmars on 
arrival rest much and appear to sleep a good deal in the first few days. 
Nor do they visit their territories regularly. The first arrivals may be 
males — among albatrosses this is certainly the case. The night-active 
petrels and shearwaters may miss one or two nights, and the day- 



1 84 SEA-BIRDS 

fulmars may skip a day or two, and at first may stay only for a few 
hours on land. Male albatrosses may desert the colony for a few days 
at laying-time. But gradually, as the colony becomes fuller with later 
arrivals, those in possession of territory are less and less willing to 
leave it, until at least one or other of the pair remains constantly on 
duty. Courtship and defence of territory are now in full swing. 

As might be expected the awkwardness of these oceanic birds on 
land (their feet are placed too far to the rear of the body to make an 
upright stance possible, except in the albatrosses) prevents a very 
elaborate display. But clashing and scissorsing of bills is part of the 
ceremonial. The courtship of the nocturnal petrels has been difficult 
to observe: but it is not difficult to hear the accompanying noises, 
which must be very nearly the most weird in nature. The shearwaters 
make indescribable crowing and screaming calls, and the storm- and 
fork-tailed petrels have squeaking and purring notes. The fulmar 
sings a curious cackling song, opening wide its dark purple mouth 
towards its mate, and waving its head from side to side and up and 
down, without moving its body much or opening its wings, as it sits 
on a cliff-ledge. In the excitement oil may be passed between the 
courting birds. Because fulmars nest in the open their display has 
been more observed than that of other tubenoses. It probably is 
typical for all these primitive, small-brained birds. Display is mutual, 
and may take place between more than two birds (Manx and little 
shearwaters, fulmar, storm-petrel), "visiting" by unemployed birds 
being a habit of the courtship period of the tubenoses up to the time 
of the laying of the single egg. 

Alone of the North Atlantic tubenoses the fulmar does not burrow, 
although it will appropriate the entrance to the burrow of other birds 
or rabbits. This may be associated with the fact that the fulmar is power- 
ful enough to be able to drive away almost every avian territorial com- 
petitor (Fisher, 1952). Normally it inhabits steep cliffs above the zone 
of the kittiwakes and guillemots, where its increase is said to have 
pushed out the herring-gulls. It has also been accused of driving 
cormorants, shags, guillemots and razorbills from the ledges; but 
there may have been a confusion of sequence and consequence, for the 
fulmars may simply have taken advantage of space vacated when 
these species were decreasing. On some islands the fulmar also nests 
on the ground, on screes, on ruins and on occupied buildings; it 
has become very plastic in its nest-site selection. 

The comparative tameness and fearlessness of the fulmar is believed 



THE TUBE-NOSES 185 

to be due not to its famous oil-spitting ability but to the fact that it is 
not heavily preyed upon by any animals save man. H. Kritzler (1948) 
says "the fulmar brain probably contains no innate mechanism whereby 
its owner is apt to respond distrustfully with regard to human beings 
. . . when food is available they are incapable of associating the manner 
in which it is presented — with possible hazard to themselves." Certainly 
fulmars are easily caught in a hand-net when attracted to the side of 
a trawler by fish offal; their desire for food overcomes the little fear 
they have of man. But it must be noted that fishermen, in general, 
seldom molest the fulmar at sea, regarding it superstitiously: there is 
a popular belief that each "molly" (fulmar) is the reincarnation of a 
dead seaman who formerly fished in that region. So man is not 
normally a predator taking adult fulmars; he collects principally the 
fledgelings (in Greenland; and formerly in Iceland, the Faeroes and 
St. Kilda). As to other large enemies, the arctic fox may kill a few 
young fulmars ; though no other predator is important. Quite a number 
of casual predators have been listed by Fisher (1952). The great skua 
cannot drive the fulmar off its nest, although gulls (glaucous especially) 
will take a fulmar's Ggg or small chick if this is left unprotected ; but, 
as we have shown, except when disturbed by man, one or other of 
the adults always remains with the egg. AVhen approached by an 
enemy, the adult fulmar instinctively spits forth oil for a distance of 
two or three feet, and although deliberate aim is unlikely, the effect 
is much the same since the fulmar ejects as it faces the intruder. The 
young fulmar is capable of spitting oil while still in the egg — through 
the pipped shell; and it spits at its parents instinctively for a few days 
after hatching, until it has recognised them as its friends. Birds, no 
less than humans, dislike being plastered with this extremely foul- 
smelling oil.* 

Some of the larger shearwaters exhibit the same fearlessness. 
The powerful North Atlantic shearwater {Puffinus diomedea borealis) is less 
nocturnal and less of a burrower than the smallest shearwaters, 
especially where it is not molested by man. On the Great Salvage 
Islands, where they are carefully protected so that the young ones can be 
collected for food when deserted by their parents, these shearwaters 
breed in almost any large crevice; both in large dark caves and in 

*Really an excretion as well as a secretion, from the alimentary system, of excess 
fat and Vitamin A. All tubenoses vomit, but the fulmar seems to have been most 
successful in turning the habit to defensive purposes, by throwing the oil towards 
the intruder. 




Fig. 



03 



Breeding distribution of the fork-tailed petrel species-pair, Oceanodroma 
leucorhoa (Leach's]petrel) and 0. castro (Madeiran fork-tailed petrel in Atlantic) 



THE TUBE-NOSES 187 

shallow openings in the volcanic rock into which the sun may shine 
upon the sitting birds. Soon after midday these great shearwaters 
begin to assemble in vast numbers on the sea close to their island, 
and long before sunset there is an exciting scene in the air as the 
flocks begin to rise and come inland, circling overhead in thousands. 
But where much persecuted by fishermen, as in the Berlengas Islands 
off Portugal, and the Desertas off Madeira, this shearwater is 
nocturnal. On Nightingale Island, Tristan da Cunha, Rowan (1952) 
found the great shearwater {P. gravis) partly diurnal. 

With comparatively few other tubenoses is it possible to witness 
this magnificent gathering of birds waiting to come to land. The 
rafts of tens of thousands of Manx shearwaters off Skokholm and 
Skomer in British waters are well known, but assemblies at sea of tube- 
noses are more generally associated with a concentration of food, as 
at whaling stations and trawling grounds. Many hundreds of fulmars 
at one time may be seen on the water close to St. Kilda, and up to 
5,000 may gather around one trawler at Rockall. J. T. Nichols (Bent, 
1922) recorded over one thousand Wilson's petrels in sight at one time 
from the coast of Long Island on 30 June 191 3. 

The courtship of the smaller petrels — ^Vilson's, Bulwer's, storm-. 
Leach's, Madeiran and frigate-petrels, visiting their burrows at night — 
has not been easy to study. Like the albatrosses of New Zealand, 
storm-petrels at Skokholm (Lockley, 1932), Madeiran petrels on the 
Desertas (Lockley, 1942) and Leach's petrels at North Rona (Ainslie 
and Atkinson, 1937) have a circling flight over the nesting burrows 
that appears to be partly a ceremonial dance, accompanied by excited 
call-notes, very soft, of the storm- and Madeiran petrels, but by 
a pleasant, almost musical, eight-syllabled cry of Leach's petrel. 
Wilson's petrel has a similar night-flight, which Roberts considers is an 
important part of their courtship, and utters a harsh call, generally as 
the bird alights near its burrow when it chatters to its mate underground 
and is answered. This night flying is characteristic of Bulwer's petrel, 
but it is silent and not so prolonged, the incoming birds seeming to 
circle for a short period as if orientating. As these circling flights 
become localised the petrels drop down to their burrows and begin 
the night's activities of burrowing, mating and incubating. Burrowing 
by petrels and shearwaters is carried out by both sexes. The bill is 
used as a pickaxe and the loose material thrown under the breast; 
the webbed feet then drag and scatter it backwards down and out 
of the burrow, as the bird lies now on one side and now on the other. 



1 88 SEA-BIRDS 

Quite hard earth and sandy rock is, by degrees, excavated with these 
feeble tools. 

Information has now been gathered to give a fairly comprehensive 
picture of the incubation and fledging periods of the tubenoses. 
Coition takes place at or near the nest. Only one egg* is laid, and if 
this is taken, even when fresh, another is not laid that year; except in 
the case of some of the large albatrosses which, although normally 
laying only one egg in two years, nevertheless lay a second egg in the 
same year if the first be taken fresh (Matthews, 1929). Deliberate 
nest building, except by the large albatrosses, is usually absent or at 
most fortuitous or haphazard. Manx shearwaters will carry feathers, 
dead bracken stalks, bluebell bulbs, roots, grass, etc., from near the 
burrow entrance or from the burrow walls and this accumulates in 
the form of a ring of debris around the egg or chick in the nest chamber. 
The chick, too, may pull material in towards the nest from the burrow 
walls. Fulmars and North Atlantic great shearwaters will pick up 
and arrange small stones around the egg. In the Berlengas and on 
Great Salvage Island Lockley found the North Atlantic shearwater 
had built quite substantial platforms of small stones, and he surprised 
one adult entering its cave with a stone in its bill. 

Incubation is by both sexes, though possibly the female sits 
altogether rather more than half the period. Several observers of 
burrow-nesting species have recorded that, in the first week after 
laying, the egg may be left unattended by day, but we are inclined 
to believe that this absence is often the result of fright due to the 
handling of the adult when its ring number is being checked. Once 
it is frightened in this way the adult may not return for more than 
twenty-four hours, but this can be now explained by the fact that 
petrels share the incubation period by taking shifts, generally of two 
or, three, but sometimes of four and up to ten days at a time; and that 
of some if not all species the off-duty bird does not usually return 
each night until the end of its "legitimate holiday" is at hand. This 
incubation by long shifts of several days has been conclusively proved 
in the case of the North Atlantic great, the Manx and the little shear- 
waters, storm-petrel, Wilson's, Leach's and Bulwer's petrels, the 
frigate-petrel, and the fulmar. There is no evidence that the incoming 
bird feeds the fasting bird, or that the male ever feeds the female 
or vice versa at any stage (we except the oil-feeding of courting ful- 
mars) ; and every indication that once incubation has begun the adults 
* A very small percentage of fulmars (probably about one per cent) lay two eggs. 





^1 
53 


72 




. . about 55 aboul 


-84 




38 


61 




42 


50 




43 


52 




48? 


58 




53 


48 



THE TUBE-NOSES 189 

only meet at the nest for a few hours during the change-over. The 
incoming bird is usually plump and glossy from the exercise and feeding 
at sea, while the outgoing bird with an empty stomach is light to 
handle, stained with long contact with the earth and dirt of the burrow, 
and anxious to escape to sea in order to break its fast. The fulmar 
incubates in spells of up to four days (Richter, 1937). 

The following are the available records of the average incubation 
and fledging periods of the petrels: 

Incubation Fledging 
Manx shearwater (Lockley, 1942) 
Little shearwater (Glauert, 1946) 
Great shearwater (Rowan, 1952) 
Storm-petrel (Lockley, 1932) 
Leach's petrel (Gross, 1935) 
Wilson's petrel (Roberts, 1940) 
Frigate-petrel (Richdale, 1943) 
Fulmar (Fisher, 1952) 

These figures show that the petrels have much longer incubation 
and fledging periods than other birds of comparable size. 

The chick is free of the o^gg forty to eighty hours after chipping. 
The empty shell is usually ignored, and may be trampled into the 
nest. The chick is covered with down; it is small, often blind (storm- 
and Wilson's petrels) and so weak-necked that it cannot hold up its 
head at first, but rests with the bill touching the ground. One parent 
usually broods it continuously for about seven days, in its incubation- 
patch, as if it were an tgg. During the first forty-eight hours it is fed 
frequently, small doses at a time, by the brooding adult, but later the 
number of meals is reduced. The semi-liquid oily food is regurgitated 
and at first held in the throat of the adult, whence it is "dribbled" 
down to the feeble chick reaching upwards with its bill. As the chick 
grows stronger it learns to feed more vigorously; the growing bill 
becomes too awkward to insert wholly into the mouth of the adult. 
The amount of food rapidly increases with each meal, and the chick 
now "inserts its bill crosswise into the parent's with its gape pressed 
firmly against that of the adult. The chick's lower mandible, which 
is shaped like a trough, is pushed up against the top of the tongue 
of the adult bird, the tip being well below the chick's bill. The parent 
now reduces the opening of its throat . . . and semi-liquid is forced 
through, in fire-hose fashion, into the chick's trough, which has an 
upslope, and down the neck. While the chick is feeding its lower 
throat and mandible keep vibrating rapidly. The small opening of 



igO SEA-BIRDS 

the parent's throat seems to act as a strainer allowing, as a rule, only 
semi-digested food to pass, and I have often seen an adult re-swallow 
larger portions of food which cannot get through. . . . Before it is 
possible to feed the chick again, the vomiting process must be repeated." 
(Richdale, 1939, on the royal albatross). 

The North Atlantic petrels are primarily plankton-feeders. Fisher 
(1952, pp. 409-32) gives a comprehensive list of the foods found in 
fulmars' stomachs; it includes remains of birds' carcases, carrion of 
bear, walrus, seal and whale, molluscs (cephalopod beaks and lenses 
are found universally in petrel stomachs), crustaceans, and coelenter- 
ates especially. All petrels greedily eat oily matter and fat, especially 
that from live and dead whales. 

Fulmars have greatly increased in the North Atlantic during the 
last two hundred years, and, as discussed in a preceding chapter 
(p. 105), this increase is almost certainly related in the first century 
to the offal supplied by northern whaling (in which right whales were 
flensed at ship's side), and in the second century to the continuous 
vast output of fish offal thrown into the sea by the modern fleets of 
power-driven trawlers and fishing boats in deep water of the Contin- 
ental Shelf; this waste is greedily devoured by fulmars which attend 
the trawling grounds in their thousands today, and every day through- 
out the year. 

Planktonic Crustacea are responsible for the red, orange or yellow 
colour of the oil which petrels eject when disturbed. This waxy oil, 
like cod-liver oil, is rich in vitamin A; it also contains vitamin D, and 
is similar in character to the oil from the preen-glands of birds.* 
Its composition is different from that of the oil of the marine organisms 
on which petrels feed, and it is certainly (Matthews, 1949, 1950) a 
stomach gland secretion and not an indigestible residue of food. It is 
generally believed that the very young chick at first is fed wholly 
on this clear oil (Roberts, 1940, p. 168), but as it grows older the crop 
of the young bird is found to contain more solid food, including recog- 
nisable portions of cephalopoda, Crustacea, small fishes, etc. Vegetable 
debris is often present in small quantities, especially in the stomach of 
the adult, such as grass, sorrel and other plant scraps, evidently 
picked up on the breeding ground. 

*Fisher (1952) has no doubt that the tubular nostrils are an anatomical adaptation 
for preening, since they are found only on birds which produce stomach-oil; and 
that there is a discharge of oil through the nostrils in preening operations. Certainly 
after vomiting oil through the mouth, fulmar and storm-petrel will be found to have 
oil exuding from the nostrils. 



THE TUBE-NOSES igi 

When first hatched the chick's body-temperature is about io°C 
below that of the adult. It therefore needs the warmth of its parent's 
body (about 38.8°C in the case of Wilson's petrel), until its own 
temperature-regulating mechanism, aided by a plentiful down, is 
developed; this occurs towards the end of the first week, when it 
'emerges' from its parent's incubation-patch; whereupon, it is aband- 
oned by the day and not ever brooded by the adult again, although 
occasionally an adult will remain by day in the nest, sitting beside 
the chick quite late in the rearing period. 

Wilson's, Leach's and storm-petrel chicks, born in cool latitudes, 
are feeble and blind when born and develop slowly. The chick of 
Bulwer's petrel, on the contrary, born in the warm latitudes, has its 
eyes open and is extremely active. It grows rapidly. It has no bald 
spot on the crown as have the storm- and frigate-petrels. 

After the first week, then, the regular attention (one might justifiably 
say, the Gropyrj of the parents for the new-born) which the chick has 
received suffers a gradual change. It was first fed a few hours after 
hatching and again several times during the first twenty-four hours 
(Richdale, 1943, p. 113, on the frigate-petrel), so long as the adult, 
with ample reserves of "oil" in its crop, was there to brood and care 
for it. But once (aided by good feeding) it has reached the homio- 
thermic stage it is left alone by day. The adults (of some species at least) 
now go farther to sea, seeking solid food, and do not return at all on 
some nights. Ringing of breeding Manx shearwaters has shown 
(Lockley, 1942) that the adults, with mates on eggs at Skokholm, may 
travel as far south as the Spanish coast, six hundred miles distant, to 
feed (principally on sardines — they are shot or caught by Basque 
sardine fishermen) ; this voyage of one thousand two hundred miles 
there and back could not be accomplished in less than two days, and, 
allowing time for feeding, probably longer. Incidentally the value 
of this patient ringing of several thousands of these birds on their 
remote breeding island was never more obvious than in the proof of 
this amazing journey of the breeding shearwaters. 

During the latter half of the eight to ten weeks of the fledging 
period, feeding becomes more and more intermittent. During a 
moonlit period several nights may elapse without the Manx shearwater 
chick being visited. The burrows of \Vilson's petrel are often blocked 
by snow, for several days, but even when clear of snow they are not 
regularly visited; and the unfed nestlings lose weight. The chick of 
Leach's petrel is fed irregularly; it has even been suggested that the 



192 SEA-BIRDS 

adults may visit the colony without feeding it (Ainslie and Atkinson). 
This supposition was intended to explain the excessively large number 
of adults present in relation to the number of young birds which were 
fed; but we believe that this increase is explained more satisfactorily 
by inferring that at that time (July-August) on North Rona there was, 
as in other petrel colonies in midsummer, the usual influx of yearling 
or "sweethearting" birds. Irregular feeding begins quite early in the 
frigate-petrel (Richdale) and also the little shearwater (Glauert says 
"normally the chick is fed every second night for the first fortnight"). 
Intervals of two to three days between feeding is recorded of the storm- 
petrel (Lockley, 1932). 

The nestling is eventually abandoned before fledging. This at least 
happens to the young of the Manx, little and great shearwaters; 
and there is very strong evidence that those of the storm- and Leach's 
petrels and fulmar are forsaken in like manner. The '^''starvation 
theory", of abandoned fasting nestlings^ has also for long been widely 
stated to apply to the largest of the tubenoses, the albatrosses; but 
recently Richdale (1952) has shown that the royal albatross Diomedea 
epomophora has no starvation period^ and he summarises evidence to show 
that other species, including the wandering albatross D. exulans, have 
little, if any. The same may apply to at least one of the smaller petrels^ 
for Roberts (1940) suggests that the Wilson's petrel is not abandoned 
and may be fed even after it is fully fledged. However, it does seem 
to be a fact that among all tubenoses intensively studied, apart from 
albatrosses and Wilson's petrel, the young is positively deserted at the 
end of the fledging period and stays on its nest for a time much longer 
than the normal interval of parental inattention, being then fat and 
as heavy as or slightly heavier than an adult. For the great shearwater 
the period between the last feed and the flight to the sea is about 
a month. For the Manx shearwater it is ten to twelve days and for 
the little shearwater eight to thirteen days. At the end of this period 
of starvation the subcutaneous and body-cavity fat is greatly reduced 
by absorption into the blood stream and apparently is partly used up 
in hardening and setting the feathers. 

When there is room to do so the abandoned chick exercises its 
wings much during this period. Thus young fulmars are seen to flap 
their wings as they sit on ledges in September, and even flutter from 
one ledge to another; while the few remaining adult fulmars, taking 
no interest in them, visit and gape and enjoy themselves elsewhere on 
the ledges. Abandoned Manx shearwater fledgelings come out from 



THE TUBE-NOSES 193 

their burrows at night and stretch and exercise for an hour or two, and 
then return to the safety of the burrow. So does the young mutton- 
bird, Pterodroma macroptera, which emerges from the burrows after 
dark and ambles "about in an aimless fashion over tree-stumps and 
other obstacles. They often return again to the burrow before daylight, 
but sometimes take wing." (Falla, 1934). Those shearwaters which 
are born in burrows in the centre of islands where predators are 
numerous (as at Skokholm) may not reach the sea in one night. 
If the weather be calm, the young bird is quite unable to rise off level 
ground, and can only flutter down inclines. Unless it can find shelter 
before dawn, therefore, it will probably be killed by gull or hawk. 
But on other large islands, where there are no predators, the fledgeling 
journeys safely by easy stages to the sea. Where shearwaters breed 
in holes on steep cliffs, as in the Faeroes and Iceland, the take-off" is 
only a matter of fluttering downwards, and the young bird, once 
airborne in a good breeze, flies well by instinct. Normally, however, 
the young shearwater flutters to the sea and makes its way into the 
ocean by vigorous swimming. When attacked at sea by a predator it 
dives deep, swimming for a long distance under water. It may be 
aided on its first flight by autumn breezes ruffling the sea and thus 
assisting it to take off'. Yet numbers of young petrels, shearwaters and 
other newly fledged sea-birds get caught inshore in severe equinoctial 
gales and are drowned in the breakers or carried far inland. The 
westerly gales regularly experienced off' the west coast of the British 
Isles in the autumn result in such a crop of inland records of Manx 
shearwaters and storm-petrels that the late T. A. Coward erroneously 
inferred that there was a regular migration overland. A study of 
meteorological records, however, has proved that these occurrences 
are always preceded by severe westerly gales. 

It is difficult to see how the chicks of some of the smaller petrels, 
nesting deep among boulders and cliff" debris, can find space in which 
to exercise and strengthen their wings before going to sea. It is remark- 
able that the storm-petrel at this stage, with tufts of down still adhering 
to its plumage, when taken from a rock crevice and dropped towards 
the sea, avoids the water and will fly — though it has apparently never 
fully stretched its wings before — making for the horizon low over the 
sea. As long as the observer can watch it, it continues on the wing. 
Well may we wonder at the astonishing vitality of these frail looking 
petrels — storm-. Leach's, Wilson's, Bulwer's and frigate-petrels. On 
land they are much more nimble than the heavier shearwaters. 



194 SEA-BIRDS 

So far the breeding of shearwaters inland has been little studied. 
Manx shearwaters breed on mountains in sight of the sea in Scotland 
(islands of Rhum, at over 2,000 feet, and Eigg, over 1,000 feet high) 
and in Madeira (over 4,000 feet high). Cool windy conditions akin 
to those of the islands exist there, and presumably the nesting and 
rearing procedure are similar. We can suppose that when the deserted 
youngster is ready to fly it has only to scramble down the mountainside 
until some sheer cliff or rock enables it to become airborne. 

The young bird has flown. When will it return to the colony? 
How long does it remain solitary at sea? These questions are difficult 
to answer. Rowan (1952), computing the population of great shear- 
waters at four million breeding adults on Nightingale Island, Tristan 
da Cunha, considers that the vast numbers of Puffinus gravis still in 
north Atlantic waters when the breeding season begins in the south 
may be explained by the supposition that these absentees are immature 
non-breeders. The great shearwater begins visiting its burrow late in 
August, the tgg is laid early in November; but from August to Novem- 
ber inclusive this species is common in the eastern north Atlantic. 
These non-breeders probably approach Tristan, as Manx shearwater 
non-breeders approach and visit Skokholm, towards the middle of the 
nesting season, making in fact a trial landing in preparation for the 
years of regular breeding ahead. At any rate it seems clear that the 
adolescent shearwaters move more or less independently of the mature 
adults in their first year. They may, in the case of gravis which is a 
large bird, spend two or more years of vagabondage at sea, like the 
albatrosses, and as Fisher suggested (1952) like the fulmar. 

The marking of individual Wilson's petrels over two years in 
Graham Land, of Manx shearwaters over a period of sixteen years 
at Skokholm, and of albatrosses in New Zealand have shown that the 
young bird does not return to the exact site or colony in which it was 
born and reared, although it does normally return to breed on or near 
the same island. As it is deserted before it is fledged it has no family 
ties, and must establish for itself a niche in the colony when it is old 
enough to reproduce. It may even have to fight for possession of such 
a territory in an overcrowded breeding-ground, or it may go elsewhere 
and colonise a new site. Single birds have been seen endeavouring 
to enter burrows occupied by mated pairs, and Rowan records (1952) 
a great shearwater which suffered bleeding and disarrangement of 
plumage in its persistent attempts to enter a burrow in which a pair 
were noisily courting. 



THE TUBENOSES I95 

The arrival of unattached and inexperienced birds at the colony, 
usually late in summer, is (as we have already pointed out) of biological 
value to the species, since it enables these immatures to "practise" 
for the following years when, with their breeding organs fully developed, 
they will present themselves in better time to secure territory and mates. 
The term "sweethearting" has been appropriately applied to the 
behaviour of these non-breeding shearwaters and petrels which sit 
about in pairs in the colony, often occupying some hole or platform 
quite inadequate for proper nesting. They are only playing at house- 
keeping and are gone after a few hours. An examination of the ovaries 
and testes of these pairs of non-breeding adults has shown that they 
are little developed and have never been used for breeding (Lockley, 
1 942) ; these midsummer visitants were of course not confused with 
the chicks, which were at that time freshly hatched. The visits of the 
immatures cease some time before the fledgelings are grown and old 
enough to leave the breeding-ground; Rowan (1952) has disposed of 
Wilkins' observations that the great shearwaters occupying burrows 
at the end of the season were adults, by proving that they must have 
been fully plumaged fledgelings deserted and waiting the psychological 
moment for departure to the sea. 

The cycle is complete. We come back to where we started from — 
the fledgeling, alone and unguided except by its inherited instinct, 
overtakes the adults which are now deep in moult at sea, and may 
go on to winter in waters several hundred miles beyond. In the follow- 
ing year it may not return to the place where it was born. It may spend 
its first "adult" summer entirely at sea, which would mean that it 
would not return to the land for nearly two years; probably three or 
four years would be nearer the truth. After a few years of wandering 
at sea, for instance, the fulmar develops an incubation patch and a 
drive to sit on a nest-site, but cannot lay or fertilise an egg for another 
four to five years. Probably not until it is 7, 8, or 9 years old does the 
fulmar breed, and then it does so regularly each summer or so long 
as it is healthy and able to find a mate (Fisher, 1952). New, eggless 
colonies of fulmars, and of Manx shearwaters (Lockley, 1942) have 
been recorded during the breeding season; these virgin colonies are 
composed of inexperienced and sexually immature birds. 

Recent ringing results (Skokholm Bird Observatory Reports for 
1946 to 195 1 ) have indicated that among the Manx shearwaters there 
is an interchange of non-breeding individuals between the islands of 
Skomer and Skokholm, two miles distant, each carrying many 



igG SEA-BIRDS 

thousands of pairs, and also between Skokholm and Lundy (forty-three 
miles distant), which has only a small colony. This interchange would 
have the effect of ensuring specific uniformity in the shearwater popu- 
lation of the Bristol Channel islands, which in fact is the case. Further 
ringing is desirable to discover if there is an interchange of young shear- 
waters of the Pembrokeshire islands with those of the Isles of Scilly and 
the Irish breeding colonies, for it is only by such evidence that the 
wanderings of the immature individual^ and the extent of its 
community, may be known. 




G. Harber Hall 



Plate XVIIa. Braking, preparing to land, Bona\"entvire 



b. Adult Gannet in attitude adopted when about to take flight from a crowded colony 

(at Grassl:olni) 

R. M. Locklev 



var" 




Plate XVIIIa. {above). At Grassholm. A Gannet arrives with a beakload of dried grass — 
stolen from a neighbour's nest ; b, Gannet about lo days old ; c, Gannet in its first 
(immature) plumage about to leave the nest {Photographs by R. M. Lockky) 



CHAPTER 9 

THE PELICANS 



ALTHOUGH DIFFERING outwardly from each other much in form, 
size and habits, the fish-eating peHcans comprise a natural order 
{Pelecaniformes) , ranging over all seas and zones, which is quite distinct 
from other sea-bird orders. They are powerful swimmers and divers, 
having all four toes directed forwards and connected by strong webs. 
The inner edge of the third toe is pectinated, forming a tooth-comb 
which is used for scratching the plumage for lice and other parasites. 
In temperate and sub-arctic latitudes of the North Atlantic the gannet 
and the cormorants (including the shag) are the familiar representatives. 
The pelicans, darters, boobies, frigate- and tropic-birds are confined 
principally to the tropics. 

The powers of flight vary: the cormorants, birds which spend 
more time resting on land than swimming or flying, and migrate little, 
are rather slow and laboured in flight, while the more pelagic gannet 
is fast and powerful. The frigate- and tropic-birds can sustain an 
apparently effortless aerial manoeuvring that is nearest perfection. 
This air mastery, and the great assemblies at the breeding cliflfs and 
islands, make the pelican tribe the most spectacular among sea-birds. 
It has been estimated that 100,000 brown pelicans are in sight at once 
on the guano islands off* the coast of Peru. On San Martin Island, 
California, about 350,000 nests of the double-crested cormorant were 
estimated by H. W. Wright (191 3). In North Atlantic waters, e.g. 
Bonaventure in the Gulf of St. Lawrence, Eldey near Iceland, St. 
Kilda in Scotland, Little Skellig in Ireland, and Grassholm in Wales, 
thousands of white-plumaged gannets are in the air together, perform- 
ing a magnificent revolving circle above their densely packed nesting 
rock. 

Although the pelican tribe are all, more or less, colonial nesters, 
they are not always sociable away from the breeding colony, with the 
exception of the true pelicans. They are more often seen at sea singly 



igS SEA-BIRDS 

or in small parties; but they may roost communally. In flight there 
are no very closely co-ordinated movements as in flocks of shearwaters, 
waders and starlings. But when a shoal of fish is sighted numbers 
come together in one spot and there may be all the appearance of 
co-ordinated action. The little black cormorant {Phalacrocorax sulcirostris) 
and the white pelican {Pelecanus erythrorhynchos) have a communal 
method of fishing. They gather in large companies and fly in long 
columns until a shoal is encountered; the leading birds wheel round, 
settle on the water, and proceed to concentrate the shoal by an ever- 
narrowing circling movement — diagram A (Serventy, 1939). The 
guanay cormorant ( P. bougainvillii ) actually appears to send out 
scouts, which indicate prey as vultures do. 





Fig. 34 
Path of fishing cormorants; A: after Serventy (1939) ; B: after Steven (1933) 



Steven ( 1933) observed that a single shag rounded up a shoal of 
sand-eels, then fed as it swam through the centre of concentration — 
diagram B. Taverner (1934) says that double-crested cormorants 
(P. auritus) will spread themselves across the mouth of a bay, and 
make a drive towards a common centre. The scene becomes more and 
more animated as the fish are congested in shallow water. The divings 
become shorter and more rapid, and more fish are tossed and swallowed 
in hurried haste for the next beakful. At last the surviving fish make 
a despairing rush through the ranks of their enemies. The birds 
then form lines again along another section of the water to repeat 
the operation. Some of these rafts may consist of 1,800 to 2,000 
individuals. 

Where cormorants and pelicans fish together the more agile cor- 
morants will steal fish in front of the open scoop-like bill of the pelicans 
which are greedily filling their huge pouches; and the brown pelican 
has a pouch capacity of 3^^ gallons. The man-o'-war bird Fregata 
magnijicens, which is expert at snatching fish from the mouth of the 



THE PELICANS igg 

overloaded pelican, can fish on its own account, plunging downwards 
from a great height, but because it prefers not to wet its non-oily 
plumage it deftly scoops its prey from the surface. Most of its food, 
however, is obtained parasitically by robbing other birds, skua-like, 
on the wing. Its powers of flight are truly magnificent — the normal 
floating progress by easy beats of the half-open wings suggests a great 
reserve of power, which is proved when it easily overtakes the fast- 
flying boobies. 

Gannets, boobies and tropic-birds dive for their food; they live 
principally on surface-swimming fish (mackerel, herring, pollack, 
garfish, haddock, whiting, sea-trout and gurnard are recorded for 
the gannet). Cottam & Uhler (1937) state that the more sluggish 
surface-feeding and shallow-water fishes not utilised by man greatly 
outnumber the valuable species and are more easily captured, and in 
consequence they compose the bulk of the diet of fish-eating birds. 
In 191 8 the American Federal Food Administration found that the 
eastern brown pelican [Pelecanus 0. occidentalis), to the surprise of its 
accusers, was innocent of consuming large quantities of food-fish, and 
that it lived principally on the menhaden, an oily fish never used for 
human consumption. Shags (see p. 118) feed mainly on fish of no 
commercial value (Lumsden and Haddow, 1946, who examined the 
stomach contents of 81 shags in the Firth of Clyde). Flat fish form 
about 40 per cent, of the diet of European cormorants (Steven, 1933). 
Other fish commonly taken include pollack, wrasse, haddock, codling, 
whiting, garfish, sand-eels, herring, mackerel, small conger-eels, plaice, 
mullet and sticklebacks. They are coarse feeders, especially the cormor- 
ant which has frequently been known to attack crabs, and to eat 
carrion — a kitten eleven inches long was found in the stomach of a 
British-taken cormorant. Both cormorant and shag, when diving, 
may sink under from the surface with scarcely a ripple, but the usual 
habit is to make a semi-circular leap out of and back into the water, 
so gaining impetus for swimming below. When travelling fast under 
water, the bird keeps its wings closed; and the body is propelled with 
simultaneous strokes of both feet. The wings are only used when the 
bird is beating about on the bottom of the sea hunting for flounders and 
other fish concealed there. It has been suggested that a silvery "flash" 
of light, reflected from the back of the cormorant's head, as 
observed in a cormorant in an aquarium, attracts fish towards the 
bird, but there seems to be no proof of this as a fact of such 
biological importance. 



200 SEA-BIRDS 

The food and fishing methods of the gannets have been well 
described by Gurney (191 3), who concludes that the deeper the fish 
are swimming the higher the altitude from which the gannet's plunge 
is made. He records that the Belfast fishermen are thereby guided as 
to the depths at which to set their nets. There is generally a mistaken 
notion that the gannet dives in order to gain impetus and strength 
to spear its prey; and the story is handed down of how trawler hands tie 
a fi.sh on to a piece of floating wood so as to deceive the gannet, which 
is killed by the impact of its dive upon the board, or else — more 
popular report still — its bill is embedded in the wood. These tales 
are largely without foundation in fact; one trawlerman told us that 
every time he tried this experiment of tying a fish to a board and trailing 
it astern when gannets were present, the fish was devoured by other 
birds which alighted beside the floating wood. The gannet does not 
spear the fish: the dive is for the purpose of gaining depth and velocity 
under water in order to attack a fish or shoal from beneath^ and the 
fish is seized in the open bill as the bird rises to the surface. It is usually 
swallowed under water, unless it is large; gannets are sometimes 
attacked and pursued in the air by skuas, and boobies are chased by 
man-o'-war birds; and it is probably from fear of these and of fellow- 
competitors (Kay, 1948) that the gannet and booby swallow as much 
of their fish-food as possible under water. Having done so, however 
they are by no means free from the air attacks of the skuas (great, 
arctic and pomarine skuas are recorded as attacking the gannet), 
and man-o'-war birds, which will often pursue them until they are 
forced to disgorge. Some skuas, particularly the great skua, will 
tenaciously follow a gannet which has been feeding, and several reliable 
observers have reported that the skua has grabbed the tail of the gannet 
in its determination to force the gannet to throw up. 

It is true that gannets and brown pelicans dive from various heights, 
according to the depths at which fish-prey are swimming (for this 
purpose their binocular vision must be functionally important) but 
records of their reaching great depths in their dives are not sub- 
stantiated. Pelicans make shallow dives, and often do not submerge 
completely. Gannets are said to be able to dive to thirty fathoms (180 
feet) on the evidence that they have been caught in nets set for fish 
at these depths. Anyone who has seen gannets diving when a herring- 
net or a trawl is being brought to the surface at sea will realise that it 
is during the somewhat slow process of hauling, when the net is floating 
near or at the surface, filled with fish, that the gannet is attracted by 



THE PELICANS 201 

the sight of this food, into which it dives and so becomes entangled, 
and after a vain struggle may be drowned before the net is brought on 
board. A net may take many hours to be completely hauled, depending 
on its length and the amount of fish taken. It is extremely unlikely 
that the gannet dives and swims to a greater depth than fifty feet. 
The cormorant and shag, which fish in shallow water, remain longer 
under the water (cormorant, 20/71 seconds; shag, up to 170 seconds, 
with an average of 53 seconds: Handbook of British Birds, IV, 1940). 
The gannet rarely remains under the surface longer than ten seconds 
and often much less; in this time it could not possibly reach a depth 
of 180 feet. Dewar (1939) finds that diving birds spend half the under- 
water time in going down and up, and the other half in fishing below. 
The rate of descent of coot and duck was i and i\ feet per second. 
Gannets, plunging from a height, would descend a little faster. No, 
the dive is short and shallow, and if it is unsuccessful the gannet 
rises into the air immediately to gain height for a fresh dive. The 
gannet and brown pelican, naturally very buoyant owing to the sub- 
cutaneous cellular tissue of the neck and upper breast, which is auto- 
matically filled with air before diving, do not usually dive from a 
floating position.* They float much higher above the water in 
swimming than do the cormorants. They are fast swimmers on the 
surface, and also underneath, when the wings may be used to prolong 
the dive and beat along the sea-floor (Kay). Before touching the 
water in their power-dives the brown pelican partly, but not quite, 
folds its wings; slow motion films have proved that the wings of 
the gannet are stretched back, unfolded, behind the body. It is 
generally believed that the wings are not used under water until 
the impetus of the dive is expended and the diver has seized, or failed 
to secure, its prey. The wings are then half opened as the bird comes 
to the surface, and typical flight motions of the wings may take place 
almost before a gannet has breached the surface. It resumes the search 
for fish, usually flying about thirty feet above the water, but when- 
shoals are at the surface it flies very much lower, moving slowly and 
frequently diving slantwise. 

All species of the pelican tribe, after gorging themselves with 
fish at a rich feeding-ground, may form quite large parties flying close 
together in irregular lines and chevrons on the return to the breeding 
or roosting grounds. Gannets and boobies, which have a thick plumage 

*But may do so if a shoal is at the surface, when, with head under water to 
look for the fish, a gannet will dive, guillemot fashion, wings half open. 




Fig. 35a 
The world distribution and numbers of breeding North Atlantic gannets; the 
results of the world gannet census in 1939. All the known colonies are marked and 
the number of occupied nests (which is approximately the same as the number of 
pairs) at each colony is shown. Circles with dotted centres show the sites of extinct 
colonies; at Great Saltee about six birds were about but no nest was found. 




b: World breeding 
distribution of the 
three species of 
the gannet super- 
species. 



204 SEA-BIRDS 

impervious to water, roost or sleep at sea except in the breeding 
season, but cormorants, shags and frigate-birds spend as much time 
as possible on land or in the air, as already mentioned. Their loose 
feathers are easily penetrated by water, and therefore they do not enter 
it except when fishing; and after fishing they spend much time extend- 
ing their wings^ and drying them in the wind and sunlight. They rest 
and roost on sand, shingle, rocks, buoys and sea-marks, posts, trees, 
even on electric power cables. Bartholomew (1943b) records 2,300 
double-crested cormorants roosting at one time on a power line in 
San Francisco Bay — a considerable strain on the cable. He found 
that non-breeding cormorants contested for the best perching sites 
on piles in California, but that the success of a fight depended not 
on absolute "peck-right," as in the domestic fowl, but upon external 
conditions such as the direction and speed of the wind, which governed 
the approach of a bird wishing to land, and a bird might have to 
crash its way through to a successful landing upon the overcrowded 
perches. These contests were purely psychological and often ended in what 
he terms "incomplete display," although the birds were non-breeders. 

The gannet and the pelican are extremely tenacious of their breed- 
ing sites; many of the gannetries have been known to be occupied for 
hundreds of years and doubtless some have been occupied for a thous- 
and or more. The colony on Lundy was known to be occupied from 1 274 
to 1909; that on the Bass Rock has been known since 1447, on Ailsa 
Craig since 1526, on St. Kilda since 1696, on Sula Sgeir since 1549, 
on the Westmann Islands since about 1687, on the Bird Rocks in the 
Gulf of St. Lawrence since 1534. 

Where the colony is a large one, the gannet, like the guillemot, 
returns correspondingly earlier in the spring. A few may settle on the 
breeding cliff at the beginning of December, although it is usually 
January before the best nesting sites (i.e., the oldest established ones) 
are occupied: at least two months before the egg is laid. One of the 
reasons for this early return has already been suggested: it is important 
for successful breeding to claim desirable housing sites within the 
densely packed colony. There is some evidence that the nest-sites on 
the periphery, the region most exposed to outside influences such as 
predatory animals and weather, are the last to be taken up — by the 
younger inexperienced adult gannets, which are last to arrive, as in 
the case of the tubenose and other sea-birds. 

All the pelicans breed in colonies, some less gregariously than 
others, like shags which, though found in colonies, sometimes build in 



^Y^Sv 



V 



^^# 






rC 



^ 



-n 



V^ 



^ 












Jfe 



*. 



H-o^ 







jv 



*,* 







Plate XXa. Dark phase of Arctic Skua incubating, Shetland 
b. Light phase of Arctic Skua incubating, Shetland 



C. A. Gibson-Hill 



C. A. Gibson-Hill 




THE PELICANS 2O5 

caves or dark holes alone, or at some distance from the nearest neigh- 
bour. Gannets never, but cormorants and shags occasionally, shift 
their colonies although usually remaining for several years in one 
place; when they move they may not travel far from the previous 
site, to which a few years later they may return. On the European 
mainland cormorants frequently build in trees or cliffs near or over 
fresh water, which they fish, but sometimes they build on the ground 
surrounded by fresh or salt water. Some cormorant colonies may 
number as much as 3,000 pairs, with other species, such as herons 
and spoonbills, nesting among them (Holland); but there are no 
cormorant colonies in the British Isles with a thousand nests. 

The display of the cormorants is more one-sided than that of 
other sea-birds. Lewis (1929) considered that it was the male double- 
breasted cormorant who initiated the breeding cycle, by taking up 
position at the nesting site and displaying and croaking when the 
female appeared. Selous (1927) thought that the female shag solicited 
the male; and Portielje (1927) and Haverschmidt (1933) showed that 
it was the female European cormorant that did so. As reversed coition 
occurs, it is still open to doubt which sex of the European cormorant 
displays most, and there may not be any hard and fast rule. In display 
the tail is held up over the head at a sharp angle; the head is then 
frequently shot forward with the bill open to exhibit the yellow mouth 
with what has been described as a "feather-duster" effect. The head 
may rest almost on the back, and the throat or gular pouch distended 
and vibrated. The whole performance is quite violent and seems to 
fascinate the watching bird, drawing it towards the performer until 
coition takes place. Some promiscuity in the cormorant, and polyandry 
in the shag, has been recorded, associated with this female display. 

Display in the gannet is mutual, while in the man-o'-war bird it 
is the male who displays, ballooning his purple throat-sac as he builds 
and guards the nest, while the large plain female brings him material. 
And it is he who will perform the major part of incubation and brood- 
ing. To a lesser extent Brandt's cormorant, Phalacrocorax penicillatus, 
expands a gular pouch, which is a brilliant caerulean blue, in display 
(L. Wilhams, 1942). 

The voice of the pehcan family is not exactly musical ; it consists of 
harsh guttural notes, although the sexual note, uttered in coition and 
fondUng, may be a pleasant crooning one. The young have a plaintive 
"uk-uk-uk" note which is the forerunner of the adult "oak-oak" 
of double-crested and European cormorants, shag and gannet). 



206 



SEA-BIRDS 




piclilis 



Fig. 36 
Breeding distribution of four cormorants: Double-crested cormorant 
Phalacrocorax auritus; Mexican cormorant, P. olivaceus; Shag, P. aristo- 
telis; Red-cormorant, Halietor africanus 



The nest, built by both sexes, is usually of marine materials; 
seaweed, flotsam, etc. Cormorants collect heather and sticks from 
cliffs near the nesting site. Gannets fly together to grassy slopes whence 
they tear off* and convey vegetation to the gannetry (Ailsa Craig, 
Grassholm). Boobies and man-o'-war birds, building in trees, steal 
twigs from neighbours' nests, and gannets rob each other in like manner. 

Little is known about the pairing of the gannet; probably forma- 
tion of the love-bond is a slow process, beginning with the meeting 
of inexperienced young adults late in the summer at the gannetry; 



THE PELICANS 207 

such gatherings of gannets in immature plumage occur in August and 
September, Having familiarised itself with the territory and even 
built a nest and paired with a bird of the opposite sex late in the summer, 
the young adult may spend one or more summers in this adolescent 
fashion before successful breeding begins. But once the bond is formed, 
probably it persists for life — at any rate the fully mature birds appear 
to be paired on arrival early in spring. It becomes a habit to meet 
at the nest, with all its associations of stimulating contact and 
ceremonial — and eventually of consummation. More research by the 
marking of individual gannets is however needed to confirm the 
invariableness of this life-partnership of this long-lived sea-bird. 

Having settled upon the nest in the early part of the season, at 
least from late February onwards, one or other of the pair of mature 
gannets will not leave it until the following July or August, when the 
young bird is sufficiently well grown to be able to defend itself from 
enemies. This alternate watch, by male and female is very necessary; 
the human observer who enters and disturbs a gannetry will notice 
how the first birds to return to their nests take the opportunity of the 
absence of immediate neighbours to steal as much nesting material as 
possible. The dry grass, seaweed and flotsam is grabbed from the 
unoccupied nest by the extended bill of the sitting bird and added to 
the robber's pedestal. 

There are other dangers to which the nesting-site is exposed when 
an adult is forced to leave the nest by the human intruder. In many 
colonies there are predators, chiefly great and lesser black-backed and 
herring-gulls, ready to pounce upon an egg or chick left undefended. 
These gulls act as scavengers to the colony, and are in constant attend- 
ance at many gannetries, and at cormorant rookeries. When disturbed 
by human visitors gannets freely, and cormorants sometimes, disgorge 
the undigested fish in their gullet before flying away. Young birds 
do the same, although they may be unable to fly; but if old enough 
they will shuffle out of the nest with cries of distress. This disgorging 
is probably an automatic reaction due to fear, but it has the useful 
result of lightening the bird for flight. The gulls eagerly snatch up the 
ejected fish, which they appear to prefer as food to the egg or very 
young gannet. The gull which takes an egg from the nest of a gannet 
which has taken flight to escape a human trespasser may open it and 
eat it in the nest, or may carry it away. Only the youngest gannets, 
in their naked black stage, are devoured, and they may be gulped down 
whole by the gull. These, then, are excellent reasons why the adults 



208 SEA-BIRDS 

should maintain a watch throughout the critical months of nest-building 
and incubation and the period of the chick's helplessness. 

Displaying paired gannets stand face to face, the wings half open 
and the tail depressed; the head and the wings are waved, the bills 
clashing, rattling and colliding like castanets. This astonishing mutual 
display may continue for minutes, with short pauses. It is varied by 
one of the pair curtseying, but as there is already little room for two 
birds on the narrow pedestal nest, the performer sometimes loses 
balance in an undignified manner. The curtsey is best seen when the 
performer is alone at the nest — and the individual, without or with 
egg or chick, frequently indulges in this peculiar, graceful, and digni- 
fied ceremony. The head is thrust underneath the body or one wing 
with a serpentine movement, and next thrown high in the air and 
shaken to and fro, usually to the accompaniment of strident urrah 
cries. This performance is usually repeated in a sequence of three 
curtseys. Another activity is the picking up of apiece of nesting material, 
which is held in the bill, shaken, and sometimes tossed into the air 
and caught again as if it were a fish. Probably most of these motions 
(except the billing) are derived from actions used in diving for, catch- 
ing, tossing up and turning, fish. Gannets do not feed each other 
at the nest, but they have been observed to pass seaweed from one 
to another during mutual billing. 

When about to take ofif from the gannetry the individual usually 
adopts a special posture, not unlike that of the male pelican when 
changing duty at the nest. It may be associated with the filling of the 
subcutaneous cells with air. The neck is stretched out until the beak 
points upwards at right angles to the ground, and the bird marches 
towards the edge of the colony, the wings slightly open, the whole 
attitude suggesting fear of attack from the bills of neighbouring birds; 
to the human observer this fear seems perfectly justifiable — if the 
marching bird passes within striking distance of a sitting gannet it 
is at once attacked. When the site of the gannetry is on level or fairly 
level ground, and there is no easy take-off from the cliff-edge, the 
posturing gannet turns round and round on the nest before suddenly 
launching itself into the air. But this leap may not be successful; 
the bird may crash into the ranks of its neighbours, and will then 
receive a severe drubbing from their beaks as it blunders down towards 
the sea. 

The coition of all pelicans takes place on the nest. The male 
gannet grips the golden head of the female in his bill; as a result it is 



Plate XXIa. Light phase 
Arctic Skua in flight 

{Eric Hoskins) 



b. New-liatched chicks of Arctic 
Skua showing egg-tooth 

(C. A. Gihson Hill) 




■if ,-' 



iS^^<Jr- 



''Mtm. 




Plate XXIIa. Courtship and tnreat display of Great Skua 



C. A. Gibson-Hill 



h. Stooping to a frontal attack on the camera-man. A Great Skua or Bonxie at 

Noss, Shetland 



James Fisher 




THE PELICANS QOQ 

usually possible to recognise the sex of breeding pairs during the summer 
by the pecked condition of the back of the neck of the female. The 
gannet only lays one egg, although two have been recorded. The 
majority of gannet eggs are laid in April and May. A second egg is 
laid if the first is taken or lost soon after being laid. There is no brood 
spot, the egg being incubated under the webbed feet; one foot is 
carefully placed over the egg and the other is rested over the first, the 
whole being covered by the bird as it sinks on to the nest. The gannet 
egg hatches after six weeks, those of cormorant and shag in less than 
four. The nestling is entirely dark blue, without down, blind and almost 
helpless. It is kept warm for the first seven days or so in the same way 
as the egg is incubated: that is, by the feet cupped over it, with the 
adult body feathers as an outer "quilt." But this special brooding 
ceases after 10-14 days. The early stages of feeding show a remarkable 
tenderness and care of the small chick by the large and somewhat 
clumsy adult. The wobbly head and neck of the new-born chick is 
scooped up in the wide-open adult bill, which is pressed sideways 
over the nest and apparently steadied in this position, while the semi- 
liquid partly-digested fish is mouthed down by the half-hidden 
chick. 

The nestling is not able to open its eyes until it is at least a week old, 
when the first down begins to appear; this is white on the gannet and 
boobies, and black on the cormorants. Voice comes to the chick at 
the same time, and it is able to hold up its head more steadily. When 
hungry, the chick now makes a soft throaty call, and reaches up to 
bill the adult invitingly. Growing still stronger, it is able to reach 
further into the distended gullet of the adult, until when it is between 
fifteen and twenty-five days old, the young bird's head actually 
disappears into the distended upper throat of the adult. Compare this 
method of feeding (with stored and largely undigested fish) from the 
elastic gullet of the gannet, booby and pelican, with that of feeding 
in the petrels, already described, in which the adult has a non-elastic 
throat, and the semi-digested food is pumped up from the proventri- 
culus and carefully controlled and doled out through the constricted 
throat aperture. 

The gannet chick, now covered in a thick white down, preens 
constantly at this stage, especially after meals; and clouds of down 
float over a large gannetry from June to September. Meanwhile 
the supply of fish has become larger in quantity and size, until at 
thirty to forty days old the young gannet is swallowing quite substantial 



210 SEA-BIRDS 

fish, even well-grown mackerel, gurnard and garfish (the spike-nosed 
eel-like garfish is doubled over and presented to the chick middle first.) 
The heads of such fish are always partly digested, as they lie head down- 
wards in the stomach of the adult — this makes them soft enough for the 
chick to swallow, although the tails remain still quite fresh and hard. 
How the turning round of the ejected fish is accomplished, during the 
act of transference from the gullet of the adult to the gape of the nest- 
ling, so that the hard spiny fins and tail enter the stomach of the young 
bird with their needle-like points trailing backwards, does not seem 
to have been studied. But we have watched captive young gannets 
swallow large fish tail first occasionally. 

Gannets feed their chicks usually in the early part of the day, on 
the return of one of the parents which has been at sea all night. 
While in camp for a week in June 1934 at Grassholm we noticed that 
at night each nest contained one adult only, with the egg or chick. 
There was no activity of any kind during the midnight hours when 
the whole colony was silent and asleep (as in booby, pelican, cormorant 
and man-o'-war colonies). Early in the morning parties of gannets 
began to fly in from the sea; many seemed to have arrived earlier and 
were discovered to be floating on the water near the island at dawn. 
Some feeding takes place at odd hours throughout the day, but the 
young gannet is not fed at all frequently, probably not more than two 
or three times during twenty-four hours. 

At six weeks of age the nestling gannet has begun to grow feathers, 
the speckled or so called "pepper-and-salt" plumage of its first winter. 
Soon it appears larger than the adult, on account of the amount of 
fluffy white down still adhering about the feathers. Its head is now 
too large to enter far into the gullet of the adult when it is being fed, 
and the whole process of feeding at this stage looks remarkably 
awkward, almost violent, giving the appearance of the young bird 
stabbing the open mouth of the adult, and of the adult trying to 
swallow the beak of its child. It does not seem surprising therefore 
that the adults give up this uncomfortable feeding process gradually; 
and about the eleventh week, or a few days later, the parents cease 
altogether to feed their chick. In its turn the chick appears to show no 
further interest in the adults, although some of these (it is not proved 
that these are the parents, however) may continue to visit the colony 
long after the last chicks have become independent. At this stage the 
young gannet is excessively fat, as the wild-fowlers of the last century 
well knew. This was the season when the men of St. Kilda, as recorded 



THE PELICANS 211 

in chapter 3, p. 93, collected many thousands of gannets and pre- 
served their carcases for the winter. 

The fledgling gannet remains on the cliffs for a week or ten days, 
during which it loses the rest of its visible down. It may not remain 
in the nest, but often wanders to the edge of the cliffs where it exercises 
its wings, frequently in the company of other fledgelings. Any adults 
present appear to ignore the grown fledgeling, and to be much occupied 
in their own posturings in a recrudescence of the ceremonies of spring 
— nest-building and emotional interchange. For the young bird this 
is a period of fasting which will reduce its weight from over 9 to under 
8 pounds and enable it to launch itself on a long flapping downward 
flight to the sea. Thus, quite unassisted by its parents, which may or 
may not be present on the cliffs at the time (but which, if so, have 
completely lost interest in their child), the fledgeling takes to the sea. 
Floundering downwards (since it is yet incapable of sustained flight) , 
the young gannet, in the absence of any headwind, ends up by striking 
the water clumsily and with some force. It may even fail to reach the 
sea in the first attempt and may bounce against the rocks, but, being 
fat and well covered with feathers, as well as possessing a shock-absorber 
of air-filled cellular tissue about the neck and breast, it is not usually 
seriously damaged, and continues to scramble downwards until it 
reaches the water. It cannot fly, and it has not been observed to dive 
from the floating position. It remains floating on the surface, swim- 
ming as fast as possible away from the land. Drifting on the strong 
tides which beset the islands and headlands where gannets breed, the 
young bird makes all haste to get out in the open sea. Kay (1949) 
gives an account of the haste of the fledgeling to get away from the 
Noss colony, swimming at a half to three-quarters of a mile an hour, 
unable to fly or dive, but flapping its wings often. It is quite alone 
and makes no effort to associate with its fellows which are launched at 
the same time. The adults continue to ignore it; all reliable evidence 
proves this in spite of published stories about young gannets following 
their parents (or other adults) at sea in autumn. If anything, adults, 
meeting them by accident at sea, may attack (Perry, 1948). The evid- 
ence that casual adults may respond to the food-begging actions of 
young at sea (Perry, 1950) is, in our opinion, unsatisfactory. Boobies 
and tropic-birds are likewise independent and solitary at this age. 

Up to the end of the first week of its existence the life of the young 
cormorant or shag is similar to that of the young gannet. But cormorant 
and shag lay from two to six eggs, and these hatch in about 24 days, 



212 SEA-BIRDS 

in the order in which they were laid. The young birds are therefore 
of different sizes while in the nest, and it is usual for the first hatched, 
by claiming the largest share of the food supply, to remain the largest 
and strongest throughout the fledging period. In times of food shortage 
the youngest may perish of hunger. H. F. Lewis (1929) found that the 
young double-crested cormorants were given pebbles incidentally 
with their fish food from the parental gullet; and they accumulated 
large numbers in this way — 75 small pebbles weighing 46 grams in 
one bird about three weeks old — because they could not get rid of 
them until they had sufficient strength to regurgitate. 

The stench of a gannetry, cormorant or pelican colony is due to 
the voidings of these birds, which subsist on large fish; but the young 
bird, except during the first few days of its life when its excrement is 
minute, is soon able to eject its waste matter to fall outside the nest- 
cavity. This, and the pedestal shape of the nest, ensure a comparatively 
dry and clean bed in stinking surroundings.* Lewis, testing the sense 
of taste and smell in the double-crested cormorant, found that fish, 
treated with strong liquids such as quassia and asafoetida, and also 
stinking bad fish, were freely eaten. 

Lewis considers that cormorants are intelligent and can become 
fond of their human owner. Alan-o'-war birds are easily tamed. 
Gurney remarks on the affectionate disposition of the gannet, both in 
captivity and towards its mate. A friend tells us that a gannet became 
so tame in captivity that it used to delight in rubbing its neck against 
her legs, and liked to be taken in her arms, when it would press its 
head against her neck. Shaking and rubbing movements of the head 
are characteristic of the emotional ceremonies at the nesting-ground. 

Haverschmidt suggests that European cormorants may raise more 
than one brood in the season. Eggs may be found from February to 
August in southern Britain and the Channel Islands, and all the year 
round in the tropics. Young cormorants and shags certainly mature 
rapidly and are able to fly well at six weeks old when, although some- 
what neglected by their parents, they do not appear altogether 
deserted. Turner (1914) records how the adults accompanied their 
young back to the nest 18 days after they had been fledged; these 
young cormorants were born in a tree-nest, and were observed play- 
fully pulling off leaves, dropping them outside the nest and then 
watching them flutter out of sight, as if idly curious. 

*The booby, Sula dactylatra, nesting on arid tropical cliffs, makes no nest, but squirts 
its faeces in a circle clear of the centre. The hot sun immediately dries the waste matter. 



THE PELICANS 213 

The ability to fly well would seem to be important for the survival 
of juveniles of a species with non-waterproof plumage, at least in 
stormy northern latitudes where a heavy surf might make a landing 
from the sea hazardous. (But. in the calm equatorial waters of the 
Galapagos Islands there is a flightless species of cormorant; its life 
history otherwise resembles that of other cormorants.) Thus young 
cormorants can escape equinoctial gales by flying to the shelter of the 
rocks, for they would drown if they could not. At what age the brown- 
black plumaged Phalacrocorax species breed is not known. It is rare, 
but not unknown, to see a gannet mated and with tgg or chick while 
still carrying signs of immature plumage. It is not until the third 
summer and fourth winter (that is, when it is three years old) that 
the head and neck of the gannet are quite white, but the golden tinge 
is almost absent; the rest of the plumage is like that of the fully adult, but 
some of the wing feathers are still black (the secondaries are black with 
some white), and the outer tail feathers are white and the inner ones dark. 
The bird is in adult plumage when it is between four and five years old. 

The vital statistics of sea-birds have ever been a puzzle to orni- 
thologists. The northern gannet, laying one ^gg, and today subject 
to hardly any persecution by man, thrives and is increasing. The 
cormorants lay between two and five or more eggs, are very heavily 
persecuted and shot, chiefly by fishermen who resent their depredations, 
but yet numerically they remain scarcely changed from year to year. 
Out of many hundreds of cormorants ringed in the British Isles more 
than 50 per cent have been shot, caught in nets, or otherwise killed 
after five years; while their breeding colonies are frequently raided 
by fishermen who destroy the young birds. It is therefore obvious that 
in order to keep their number even stationary, the cormorant must be 
a fairly long-lived species. In captivity it will live about lo or 12 
years. David Stuart (1948) finds that the expectation of life on i 
March (following the year of its birth) of the young cormorant (born 
and ringed in a colony of 200-220 pairs at Mochrum, Wigtownshire, 
Scotland) is only 2.2 years; which he finds makes it impossible for 
the cormorant to maintain its numbers (on paper) as it has done in 
fact, at Mochrum, for at least 80 years. But it should be remembered 
that aluminium leg-rings wear and drop off' the legs of sea-birds after 
a few years; the data accumulated by ringing can only be a guide to 
the vital statistics. Among some birds (e.g. Manx shearwater) which 
nest year after year in accessible sites, it is possible to obtain greater 
accuracy by frequently renewing the rings of individuals under study. 



Fig. 37 
Breeding distribution of the cor- 
morant, Phalacrocorax carbo. Black 
dots represent some known breeding- 
stations. The race steadi should prob- 
ably be united with novaehollandiae 




THE PELICANS 



215 



Man of course is not the only enemy of the cormorant. Southwell 
(1904) records that a hump-backed whale [Megaptera novaeangliae) 
was "found dead after indulging too freely in cormorants," having 
swallowed six and choked on the seventh. There is also a record of an 
angler- fish which had attempted to swallow a cormorant; the strength 
and buoyancy of the cormorant had raised both to the surface, where 
they were captured, but the cormorant did not long survive its wounds. 
Cormorants have also been taken by cod, angel-fish and pike (p .114). 

Cormorants have been exploited by man for several centuries, 
the Chinese breeding and training them to catch fish, on a commercial 
scale, usually in daylight; the birds are free to work in packs together 
in shallow water and are taught to return, each to its own perch on 
its owner's boat. The Japanese control their trained cormorants with 
reins attached to neck-rings, and work at night, using flares to attract 
the fish. The collection of the guano of pelicans and cormorants forms 
a major industry on islands off the west coast of South America. The 
droppings of double-crested cormorants roosting on racks along the 
shore of California are also collected to be used as fertiliser. Gannet- 
guano is regularly collected on islands off Cape of Good Hope, South 
Africa. An important account of guano is given by Hutchinson (1950). 

The true pelicans are never found far from the land in the North 
Atlantic, and therefore need not be considered in detail here. Pelecanus 
rufescens is the only breeding pelican on the east side, where it frequents 
estuaries, bays and lagoons, and nests in water-side trees. This is 
the grey or pink-backed pelican : it can drive fish downstream in a 
river, corner and devour them in shallow water. On the west side 
of the Atlantic is P, occidentalism the brown pelican, a tree-nester 
which will also nest on the ground. Pelicans lay two or three eggs, 
and their breeding biology resembles that of cormorants: they are as 
tame, gregarious, and quarrelsome as the gannets, and just as stupid 
in failing to recognise and rescue a nestling if it falls out of the nest or 
is attacked ( it may even be devoured ) by a neighbouring adult. 
Both sexes incubate the egg and brood the naked chick. They have 
been seen to open the wings as if to shelter the growing nestling from 
the tropical sun, but the action appears to be instinctive, and the shadow 
may not fall on the young at all. Those young pelicans hatched in 
tree nests remain there until they are fledged, and are fed by their 
parents; but in ground colonies the youngsters, growing impatient 
for food, wander over the nesting area in bands, pursuing each adult 
arriving with fish; a melee ensues, in which they fairly attack the 



2l6 SEA-BIRDS 

gullet of the loaded bird, which lays about with its long beak, hitting 
those it does not approve of, and apparently trying to "clear the carpet" 
for its legitimate family. 

Food is not carried in the pouch: this is used only for catching 
the fish. After the gannet-like dive, which is spiralling like that of 
the tropic-bird, the brown pelican appears at the surface quickly 
(since' it makes a shallow dive and usually in shallow water), facing 
the wind. Its first act on emergence is to drain the pouch of a gallon 
or so of water by tilting the bill; this done, the bill is flung up, releasing 
the fish, which is caught in the throat and swallowed — if it is not 
snatched skilfully in mid-air by a gull or tern hovering near. 

The boobies are the tropical representatives of the gannets of 
temperate waters, and although some workers prefer to separate them 
generically, their life-histories are so similar that the field observer 
accepts them readily under the genus Sula. Feeding and breeding 
habits are identical in main features: incubation is by both sexes, the 
young are born blind and naked, are fed by regurgitation, acquire a 
first down of white colour, and remain in the nest for about three 
months, being finally deserted by the adults. Three distinct species 
(Fig. 38) breed in the tropical North Atlantic: the blue-faced booby 
Sula dactylatra, breeding on the bare rock or cliff and making little 
or no nest; the red-footed booby Sula sula, a tree-nester; and the 
brown booby Sula leucogaster, nesting indiscriminately between these 
extremes of habitat, usually on vegetation-covered ground, but also 
in the open. All boobies feed largely on flying-fish, caught by diving, 
gannet-fashion. Two eggs may be laid and hatched, but at North 
Atlantic sites only one chick survives: the later-hatched one is starved 
and trampled to death by the voracious appetite and activity of the 
first-born.* Murphy (1936, p. 853) describes how the chick of S, 
dactylatra gropes "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 uncomfortable manner, until all the available flying fish have 
been extracted. The inordinate length of time devoted to the feeding 
of the chick . . . may be still another reason why no food ever remains 
in the gullet to profit the second oflfspring." One adult guards egg or 
chick, but when the nestling is large enough to defend itself at a month 
or so, the old birds leave it by day and go out on their excursions into 

*The Pacific representatives of the three boobies found in the North Atlantic, 
however, often rear more than one chick, which may be due to the abundance of 
fish food, especially in the Humboldt Current (Murphy). 



ng. 38 a 



Fig- 39 « 




U I I 














i ? 

1.^ i VJ 




Fig. 38 
Breeding distribution of the three Atlantic boobies: (a) Sula dactylatra, the blue-faced 
booby; {b) S. sula, red-footed booby; {c) S. leucogaster, brown booby. The last also 
breeds on an island SE of Formosa, andiS". dactylatra personata also on the Kermadec Is. 

Fig. 39 
Breeding distribution of the two Atlantic tropic-birds: {a) Phaethon aethereus, red-billed 
tropic-bird; {b) P. leptunis, white-tailed tropic-bird. 



2l8 SEA-BIRDS 

blue water (never fishing close to land) after flying-fish. In the heat 
of noon, as in northern gannetries, the downy young lie with their 
heads hanging over the edge of the nest as if dead; they are fast 
asleep. Heat is a trial surprisingly well borne by many tropical sea- 
birds. The small chick of S. dactylatra hatched on the naked rock 
may be seen climbing on to the webs of the brooding adult in order 
to avoid the fierce radiation. This species, sometimes called the great 
white booby, is the largest (and clumsiest on land) of the three, and 
roosts on open rocks when not breeding. The other two, however, 
roost much in trees : S. leucogaster will alight on the booms and wooden 
superstructure of ships and sleep soundly all night. 

The female red-footed booby S. sula, builds a slovenly tree-nest 
of sticks brought to her by the male (who is smaller in size). The material 
is laboriously collected from the sea or snapped from the trees, for 
this booby will not willingly alight on the ground, from which it 
has difficulty in rising. The young ones show the same fear of the ground 
and cUng tenaciously to the trees long after they are fully fledged. 
Deserted by the adults, they climb to the tree-tops, grow thin with 
much wing flapping and fasting, and at last take off', flying well — 
far better than the fledgelings of other Sula species, some of which 
can only flutter downwards to the sea. The red-footed booby is also 
more crepuscular than the others — it has the largest eye of all the 
boobies — sleeping much at noon and going out in search of the noc- 
turnal squid early and late in the day. Some observers suggest that its 
frequent late return to the roosting ground, after the man-o'-war birds 
have gone to sleep, is due to fear of these pirates which lie in wait 
along the edge of the breeding-roosting tree-covered shore. The red- 
foot's habit of skirting the shore until directly opposite the nesting tree 
on its return from fishing enables the man-o'-war bird to intercept the 
food-]aden booby the more certainly. 

The astonishing man-o'-war bird, Fregata magnijicens, obtains a good 
deal of its food by robbing boobies of theirs. In spite of its wonderful 
powers of flight it is very restricted in its range from its nesting-sites 
which, in the North Atlantic, are the West Indies and the Cape Verde 
Islands. The range is between fifty and seventy miles: the bird's presence 
in the Pacific was often a guide to "ditched" airmen during the war, as 
to the nearness of land. Like that of the cormorants, to which it is 
closely alKed, its plumage becomes water-logged if it is forced to swim: 
its preen gland is small, the size of a pea, and probably insufficient 
to yield much oil for waterproofing the feathers. But the man-o'-war 



THE PELICANS 219 

or frigate-bird never deliberately enters the water. It is the most 
buoyant flying machine among all birds, having the greatest wing 
area in relation to body-weight. Its long narrow pointed wings and 
great long tail are perfect instruments for the high-speed manoeuvres, 
as well as for the effortless soaring, of its incomparably graceful and 
elegant flight. The boobies, by comparison, seem to lunge clumsily 
into the sea after the flying-fish; but the arrow-fast frigate-birds 
easily overtake the flying-fish long before they drop into the water. 
The "half-beaks," fish which skim on the surface of the water are 
likewise seized by the dashing frigate-birds; and probably fifty per 
cent, of their food is taken direct in this way. Especially in rough 
weather does the frigate-bird earn an "honest living," plucking fish 
from the hollows and crests of storm-waves. It is during calms that 
boobies and other birds are most pursued by frigates which follow 
on the tail of the food-loaded booby or gull, and if the contents of the 
crop are not ejected, the tail itself or a leg of the victim may be seized 
and viciously wrenched. Frigate-birds will attend the cleaning of 
fish at sea and deftly snatch offal thrown from trawlers and 
smacks. They follow tropical rivers, frequenting slaughter-houses 
together with black vultures: the vultures snatch up the oflfal thrown 
on the ground and the man-o'-war birds that which is flung into the 
water. 

Although sedentary in its range the man-o'-war bird has been 
watched crossing over the Panama isthmus and the breadth of Cuba. 
It will visit fresh water; and has been seen to dash down and buflfet 
the surface as if desiring a shower-bath and possibly a drink. 

As with the boobies, the breeding of the frigate-birds is not fixed 
to one season of the year in its tropical range. The male first occupies 
a tree-site and sits there, inflating the bright crimson globe of his 
throat-sac as an intimidation to other males or as an invitation to 
the larger, duller female, or both. She brings the nesting material 
and, as soon as the flimsiest platform is built, mating takes place. 
The male continues in occupation of the site: it is absolutely neces- 
sary for him to do so if he would retain a nest, since the slovenly 
platform would disappear, bit by bit, in a few minutes, if he left it. 
Nest-hungry females are always ready to steal twigs and sticks; 
although there is abundant material under the trees, the man-o'-war 
is unwilling to alight on the ground, from which it finds it difficult, 
with long narrow wings and tail, to rise. She therefore robs her 
neighbours, which are often red-footed boobies, taking sticks from 



220 SEA-BIRDS 

unguarded nests or from boobies returning with material in their bills. 
The best frigate-nests are nevertheless very poor, but as the season 
advances they become soHdified with excrement. The male takes a 
large part in incubation; his ballooning of the gular pouch ceases 
then. They are tame when unmolested at the nest, and are heavy 
sleepers at night. Buller (1905, p. 50) quotes the case of frigate-birds 
being so tamed by feeding that they were used to carry messages be- 
tween two islands 100 kilometres apart; the birds became accustomed 
to being fed at perches placed for them outside human dwelHngs in 
a number of Samoan islands. They were easily handled at night when 
it was desired to affix or remove the message contained in a reed 
cyHnder fastened to the wing; and since these birds never enter the 
water the cylinder would be safe from destruction by that element. 

That curious appearance of harmony at the breeding ground 
between parasite and host often seen in other species exists between 
frigate-bird and booby nesting in the same tree colony. The booby 
may be relentlessly pursued over the sea, but enmity (except for stick- 
stealing) ends on the land. The frigate chicks may be seen in nests 
close to those containing booby youngsters, both species lying fast 
asleep at noon with downy heads drooping over the side dejectedly, 
the new quillshafts, surrounded by powerful young muscles, charged 
with blood to feed the developing wings. 

Two more remarkably beautiful tropical wanderers of the Pelecani- 
form order breed in the warm North Atlantic : the red-billed {Phaethon 
aethereus) and the white-tailed {P. lepturus) tropic-birds. Boatswain- 
bird is a title earned from the shrill whistle, the long pointed tail 
resembling a marlin spike, and the habit of coming up to inspect a 
passing ship, of these white sea-birds — which cross and recross the 
ocean desert of the Sargasso Sea, with swift dove-like ffight, at points 
farthest from the mainland in the whole North Atlantic. At Ber- 
muda the colony of 2,000 pairs of P. lepturus was counted and studied 
by Gross (19 12) and Plath (1914). The one chocolate-splashed tgg 
is laid in a hole or burrow in the cliff. Features of the breeding 
biology resemble those of the petrels: the clumsy shuffling on land of 
these wonderful ffiers, the hole-nesting, incubation by both sexes, the 
long fledging period, the desertion of the young. Pairing takes place 
at the nest. After twenty-eight days or more of incubation the feeble 
blind chick hatches. It opens its eyes in a few days, and grows rapidly 
on a diet of fish and squids. The adults make two foraging journeys 
each day: at dawn, returning in the morning; and some hours before 



THE PELICANS 221 

sunset, returning before dusk; probably these times are selected 
because the squids are not found on the surface of the sea at noon. 
The chick is fed by regurgitation; it is well feathered by the fortieth 
day and leaves about the sixty-second day after a short fast, the adults 
having quite deserted it. Like the shearwater it cannot fly, but only 
flutter down to the water, where it swims alone into the open sea. 

The red-billed tropic bird has not been so intensively studied, but 
undoubtedly has a similar life history. It is a small species. Murphy 
says it is "well named after Phaethon, the son of Apollo, who hurtled 
from the far sky into the sea. I remember the July day when I first 
saw one dive from the height of the 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." 



CHAPTER 10 

THE SKUAS 



THE GULL-LIKE SKUAS are perhaps the most primitive and certainly 
the most speciaHsed of the famihes of the Laro-Limicolae, a large 
order containing the rest of the sea-birds described in this book. 
Skuas are essentially predators and parasites: at sea they neither dive 
for food nor seek it by swimming; nor, on the land, do they seek much 
of their food by searching and probing on foot, as gulls do. Although 
they swim well, and walk with a waddling gait, they prefer to swoop 
and grab their food while in flight, piratically. All four species of the 
family (Stercorariidae) are North Atlantic, indeed, arctic, birds; it 
seems likely that the suborder Lari, to which both skuas and gulls 
belong, originated in the north. The largest of the skuas, the bonxie 
or great skua, Catharacta skua, is one of the few birds with a bipolar 
distribution. As explained (p. 143), we think it likely that this interest- 
ing species, or superspecies, originally came from the north but colonised 
the south; and that the presence of great skuas breeding in the North 
Atlantic may be a fairly recent development (geologically speaking), 
a return, so to speak, to the north of the descendants of the ancient 
stock. These are now, at least subspecifically, distinct from their 
antarctic and sub-antarctic relations. The great skua's rather narrow 
distribution in the north is described on p. 144. 

Although gull-like in appearance and habits, skuas are far more 
oceanic than gulls, travelling considerable distances on migration 
and remaining at sea throughout the winter, never or rarely roosting 
on land at that season. The bulky brown form of the bonxie, with its 
triangular white wing patch, is unmistakable; with its short tail it 
looks almost clumsy on the wing compared with the graceful long- 
tailed smaller species — the pomarine, the arctic and the long- tailed. 

These three smaller skuas resemble each other considerably in 
form, habits and distribution; and much remains to be found out 
about their fundamental ecology, in which no doubt lies the biological 



THE SKUAS 223 

secret of the separate existence of the three. Much of our knowledge 
of their at-sea distribution is obscured by the difficulty of identification 
at a distance: immature birds are almost, and sometimes quite, 
indistinguishable to the observer; they lack the long central tail 
feathers by which the adults may be specifically identified. Only the 
heavy thick-bodied immature great skua cannot be mistaken for any 
other bird, being too dark for an immature gull, and too short in the 
tail for another skua. The adult arctic skua can be recognised by the 
two long straight feathers which project from the centre of the wedge- 
shaped tail; these are distinct from the much broader and twisted 
features of the tail of the somewhat larger and heavier pomarine 
skua. The graceful long-tailed skua may be recognised by its buoyant 
swallow-like flight, and the very long and streamer-like central tail 
feathers. Both arctic and pomarine skuas have dark and light 
phases (p. 52) ; in the arctic skua the dark form is more numerous in 
the southern part of its breeding range. The dark form is scarcer in 
the pomarine. 

At the Fair Isle Bird Observatory, Williamson (1951) found that 
the phases of the arctic skua could be divided into dark, intermediate 
and pale (white-bellied) types: D, I, and P. In eight nests under 
observation the following matings were recorded in 1951 : Dx I, P x I, 
PxD, Ixl, Pxl, Dxl, Dxl, Dxl. Two adults, ringed as non- 
breeders in 1950, were again present but not breeding in 1951, arguing 
a non-breeding period of at least three years in this species. 

The Fair Isle arctic skuas obtain most of their food by forcing the 
abundant kittiwakes to disgorge the sillocks and other small fish 
which are the staple kittiwake food in summer. All skuas pursue 
other birds at sea in an attempt, not always successful, to make them 
deliver their fish catches. This food, often partly digested in the vic- 
tim's crop, is secured by the skua with a sudden swoop before it reaches 
the water. The great skua in normal flight appears sluggish and slow, 
as it forges along with laboured movement of the broad wings, but 
when attacking another bird it displays great aerial power, although 
in a deceptively leisurely manner, following the twists and turns of its 
quarry with ease. It has been seen to grab a gannet by the wing-tip or 
the tail and force its victim to disgorge, and even to retain hold until 
the gannet has crashed into the sea. It will even pursue a fulmar; 
on 16 June 1935, when about ten miles E.S.E. of the Westmann 
Islands, Iceland, we saw a great skua persistently harry fulmars 
following our ship; this does not seem, however, to be a habit, and 



224 SEA-BIRDS 

probably the skua in this instance was exceptionally hungry. During 
ten days at midsummer 1948, from a trawler working the Rockall 
Bank, we saw great skuas frequently, but they did not harry any birds 
(and there were thousands of fulmars present), being apparently con- 
tent to search for food far in the wake of the trawler, evidently taking 
the roughest offal of the fish guttings which had been thrown out 
plentifully and floated astern, after the bold fulmars in their hundreds 
close to the ship had seized the livers and tender parts. 

Gulls and terns are the principal victims of the piracy of the skuas, 
which seldom select a gull or tern that is incapable, through a long 
fast, of throwing up a contribution ; in all probability the skua recog- 
nises the appearance of a food-laden gull or tern (if the fish it is carrying 
is not visible) by its more leisurely, less hunting flight. Skuas also 
prey on smaller birds, both over the sea and the land; and if these 
are unable to escape by taking cover or diving they are relentlessly 
followed, tired out, killed and devoured. A pomarine skua has been 
seen to pursue to the death a phalarope at sea (Bent, 1921): and to 
force a fulmar to drop a fish, just south of the Newfoundland banks, 
14 April 1 92 1 (Fisher, 1952). 

Some skuas may breed far inland, as in northern Europe and 
Siberia; and the food then consists much of small mammals (lemmings 
especially), small birds, eggs, freshwater fish, insects, worms, etc. 
The great skua is probably the most marine and gull-like in its feeding 
habits, living mainly on fish, pirated or legitimately taken, and killing 
large and small birds, adult or young, along the seaboard of its nesting 
area; and it is a gull-like scavenger of stranded carcases of seal, 
whale, fish and other carrion. 

The breeding habits of the great and arctic skuas have been, and 
are being, studied, but little is known about the lives of the pomarine 
and long- tailed skuas. To their most southern nesting haunts the great 
and arctic skuas return during April. The eggs are laid a month later. 
Some of the display and posturing is similar to that of the Lams gulls, 
including the food-begging actions and mating ceremonies. In court- 
ship the male raises his wings and flutters them as he approaches the 
female. He holds his head upwards and backwards and puffs out 
the neck hackles, displaying with sharp excited calls in his effort to 
gain her attention. She responds with a wheezing or hissing note, 
sometimes standing upright and at other times bowing to the ground 
as if to invite coition. The male continues for some time a kind of strut- 
ting dance in a half-circle round his partner; and wing play goes 





/ 





\ 



y 



/ 



/ 



m 



'■ y 



t 

^ 



I 



S 



\ 



■-0 -t; 



Plate XXIVa. Herring 
Gull at nest 

{LUw. E. MoTgat 



b. British Lesser Blacl 
backed Gull 

{Eric Hoskin 




THE SKUAS 225 

on Steadily. The wings, when raised above the back, seem, indeed, to 
indicate heightened emotion at all times in the life of the skua while 
on land. Both sexes indulge in an attractive aerial display: sometimes 
soaring together in circles; or one bird will make a spectacular dive, 
or will perform an amazing twisting tumbling evolution in mid-air, 
symbolic of the piratic chases at sea. The swift downward dive is 
turned upon the human intruder as he crosses the breeding territory, 
and he will be persistently dive-bombed until he leaves the area, and 
perhaps struck on the head. The great skua also makes a frontal attack, 
by a low approach over the ground, upon man, ponies, sheep, dogs and 
other large animals, which is rather terrifying to face. This skua will 
strike with determination, and often with successful results, at sheep, 
even clinging to the wool and beating its wings about the head of the 
intruding animal. The arctic and long-tailed skuas are adept at injury- 
feigning in order to draw away from the nest the unwanted visitor; 
the adult staggers over the ground with wings trailing as if they were 
broken, but rather spoils the effect — at least for the human observer — 
by rising into the air occasionally before resuming the display. William- 
son (1929) considers that this is probably derived from primitive food- 
begging and courtship actions. 

Great and arctic skuas nest in colonies, often of large size (500-750 
pairs of great skua on Foula, Shedand, 1951). They are more sociable 
than the pomarine and long-tailed skuas which scatter their nests 
more widely on the tundra. The skua prepares a hollow for its nest, 
but adds very httle material as a lining. The usual clutch is two, 
occasionally one, exceptionally three, eggs. These are protectively 
coloured: brown or grey, splotched with irregular dark brown spots. 
In all respects the incubation resembles that of the gulls: it is by both 
sexes, and of the same duration, 26-29 days. The new-born skua is 
covered with a dark unmottled but protectively coloured down. It 
is more precocious than the gull chick, develops rapidly and leaves 
the nest early, being at first jealously attended by the adults. Skuas 
may attack and kill chicks belonging to neighbours, but there does 
not seem to be any record of that cannibalism within the family 
circle found in the gulls. At one nest on Fair Isle the parents continued 
to give the injury-feigning or lure display for five days after the death 
of their single chick (or, as Wilhamson (1951) puts it, "the normal 
parental response to intrusion persisted for some 5 days after all 
biological need for it had ceased to exist.") This chick was eleven 
days old, and the disturbing distractive behaviour of the adults is 



226 SEA-BIRDS 

probably strongest at that age (Williamson, 1 949) ; but it gradually 
weakens, until, at the end of the fledging-period, the adults have lost 
all interest in defending their young in any manner at all. Williamson 
found that the arctic skua was fledged in 27-33 days, the period varying 
probably with the abundance or otherwise of the fish-food pirated from 
the kittiwakes. 

The adults do not accompany the young skuas at sea (Perry, 1948), 
which gradually learn to feed for themselves, hawking over the sea 
after kittiwakes, gulls and terns; they will chase small birds indus- 
triously, if seldom successfully at first. The flocks of young skuas at 
British breeding grounds thin out by mid-August as one by one 
individuals take to the open sea. The adults have gone ahead, likewise 
singly or in very small parties. For the most part skuas are solitary 
at sea; but where gulls and terns concentrate to feed on shoals of 
fish, a number of skuas will gather with intent to plunder the fishers. 

The immature birds do not hurry north in the spring. We have 
seen numbers off the south coast of Portugal at midsummer. They 
may not reach the breeding ground until they are in their third 
summer. They will then take part in those social activities seen in 
individual non-breeding sea-birds of other species, previously described, 
including communal bathing in fresh water (a favourite habit of skuas), 
and incomplete courtship displays; and so they familiarise themselves 
with the future nesting region. 

The departure of the adults may be hastened in August by the 
early autumnal moult which takes place at sea. In spring there is 
another moult, into the richer coloured summer body plumage in 
which the adults arrive at the breeding grounds. The wing-coverts, 
quills and tail are apparently moulted only once a year, gradually 
during the winter, so that the skua is never much incapacitated in 
his piratical profession by this annual process. 



CHAPTER II 

THE GULLS 



GULLS ARE STRONG aggrcssivc wcll-built birds with long wings 
capable of sustained and powerful flight. They have webbed 
feet, but are good walkers on land. In the air they move with ease and 
grace, and glide without effort for long distances. The majority have 
white bodies with grey or black mantles or wings. Some have a dark 
hood during the breeding season, but this is moulted in the autumn. 
The young gulls are more difficult to identify in the field, the juvenile 
and first year plumages of the larger species being a drab mottled 
brown. 

The full beauty of flight of the gulls may be watched from the deck 
of a ship, when it will be seen that gulls are expert at taking advantage 
of the wind-eddies caused by the passage of the vessel; again and 
again they skim and circle about the ship, using the wind deflected 
against the hull to lift them, with scarcely any movement of their 
outspread wings. Over land they frequently soar, wheeling upon a 
thermal pocket of air and spiralling to a great height with no more than 
an occasional beat of the wings and twist of the tail. On the water 
they swim buoyantly as they scavenge for food. They are however 
poor divers and rarely submerge completely. 

Although some gulls migrate over considerable distances, they 
are seldom long out of sight of land; the kittiwake, which ranges 
over the whole of the North Atlantic, being the exception. At the 
other extreme, most of the dark-headed gulls spend much of their 
lives inland, often breeding far from the sea; and during the winter 
months feeding in or near large towns, and roosting on the open water 
of lakes and reservoirs at night. These smaller Larus gulls live much on 
terrestrial insects, worms and small invertebrates during the summer, 
when breeding inland; and nearly all the gulls, excepting the pelagic 
kittiwakes, and the ivory-,, Ross's and Sabine's gulls of the Arctic, 
regularly visit the land for food in autumn and winter, when seeds 



228 SEA-BIRDS 

and grain may be procured at harvest time; and they follow the plough. 
Gulls in fact are omnivorous, freely taking vegetable matter where the 
normal diet of fish and flesh — alive or as carrion — is in short supply. 
The ivory-gull lives on the droppings of seal, walrus and polar bear 
all the year round, supplemented with crustaceans, molluscs and insects 
when these are available (particularly at nesting times). The larger 
gulls in summer devour the eggs and chicks and even adults of other 
sea-birds, and often the chicks of their own species. Most gulls work 
the mud, sand or saturated turf, trampling with both feet until worms 
or sand-eels appear. The great blackback drops eggs of birds (the pink- 
footed goose included) from a height to break them, but cannot dis- 
tinguish between hard and soft ground. Herring-gulls drop small shell- 
fish (clams, cockles, mussels, and whelk-shells containing hermit- 
crabs) from a height of not more than about 25 ft., (possibly because 
of fear of a rival getting to the crushed delicacy first) on rock and sand 
indifferently, apparently unable to appreciate the greater effectiveness 
of the rock compared with the sand for crushing the shell. Common 
gulls do the same. It does not appear to be an instinctive habit, but 
rather one acquired by a few individuals only; but it is copied by 
others watching the expert at work. Rooks drop mussels and walnuts 
in the same manner. It is recorded that a highway bridge in New 
Jersey, U.S.A., was littered with the remains of clams dropped by 
herring-gulls, which in this instance seemed to have discovered that 
the road there formed a more suitable surface for the purpose than the 
nearby shore. 

Gulls like to wash their food, if it is of any size, in water. Herring- 
gulls may be observed rinsing their fish food in tidal pools. Great 
black-backed gulls will wash the sea-birds (puffin, shearwater, various 
auks) and small mammals which they have killed, in the sea, or on 
the edge of a freshwater pond or stream at their breeding grounds; 
and they leave behind in these places quite an accumulation of clean- 
picked skins and vertebrae. 

The beautiful laughing gull [Lams atricilla) , with the dark glittering 
eye encircled with a fiery ring, is an adept at stealing eggs from the 
nests of terns ; it also has a trick of alighting on the head of the brown 
pelican, and snatching food from its pouch. In turn it is much pur- 
sued by skuas and man-o'-war birds. 

Goethe (1937) has given us one of the best accounts of the breeding of 
a Lams gull in his study of the herring-gull breeding among sand- 
dunes. His descriptions of courtship, display and nesting may be 



I 




o 



'op 





J. D. Rattar 



Plate XXVIa. Iceland Gull, immature, winter. Lerwick, Shetland 



b. Iceland Gull, summer plumage 



J. D. Rattar 



THE GULLS 229 

accepted as typical for the genus. Another classical account is that of 
the black-headed gull by Kirkman (1937). Both accounts, which 
appeared simultaneously, have done much to increase our knowledge 
of gull behaviour. Paludan (1951) and Tinbergen (1953) have followed 
with other intensive studies. 

These two gulls make an interesting comparison. As a rule the 
black-headed gull arrives quite suddenly and in a large flock at its 
breeding ground, much as the puffin does, but almost a month earlier, 
in the first fortnight of March; although some scouts pay visits in Feb- 
ruary. But it does not settle down immediately. Its visits are somewhat 
spasmodic, and always during those early weeks it withdraws to roost 
away from the breeding ground. When the adults settle at the nesting 
sites in March and April, they appear to be paired like gannets, 
rooks, and other social nesters. We know very little as to the actual 
pairing up, which is said to take place before arrival. Kirkman 
insisted that the birds "have arrived paired at the breeding place," 
but Tinbergen (1952) provided proof that the male and female arrive 
separately at the breeding ground and there discover each other or a 
new mate on or near the familiar nesting site. There appears to be no 
firm evidence that any gull remains with its mate throughout the 
winter; or that they pair regularly before they leave for the breeding 
ground in early spring, in February and March. In short, we only 
know that the birds are faithful to the colony and nest-site. This 
applies also to the migratory lesser black-backed gull, which arrives in a 
body at the nesting ground in March (with a few scouts earlier), and 
it would appear to apply to all the gulls (as well as to the terns) which 
perform mass movements from wintering to breeding grounds. 

Faithfulness to the old nesting site, however, is very strong. Kirk- 
man suggests that the big nest in the centre of a group of smaller 
nests in a black-headed gull colony may be the parents' home, and 
the other nests round about are those of the children. Extensive ringing 
alone can prove this attractive explanation of the grouping of nests, 
and might also explain the interiorly family (or neutral) attitude of 
the owners, who adopt an exteriorly aggressive attitude to all others 
outside the family group. But other factors operate, and Kirkman 
himself notes that the size of the nest is largely determined by the 
number of times a bird is prevented from sitting on its eggs ; if its mate 
refuses to leave the eggs the frustrated bird finds an outlet (displacement 
activity) for broodiness by collecting and depositing material in the 
nest. 



230 SEA-BIRDS 

In order to begin breeding there must be a suitable environment 
against which the mutual stimulation of the sexes will become effective. 
Probably in most if not all gulls it is the male which sets up this environ- 
ment by occupying the breeding site first and displaying towards later 
arrivals. Almost as soon as the shortest winter day is past lone males of 
the herring-gull (which in the British Isles is largely a sedentary 
species) settle on cliff-sites on fine days (Lockley, 1947) and give the 
moaning call at sight of another gull passing near. Each male parades 
on or near a suitable platform in the rocks cliffs or dunes. He chal- 
lenges a neighbouring male by drawing his head in stiffly. He picks 
up small pebbles or plucks the stems of plants much as a farmyard 
cock will peck and pluck at the ground when approaching a rival. 
Usually the challenged male begins to pluck also as if warning the 
intruder that he has come far enough. The warning often suffices; 
energy has been released without wasteful fighting and each male 
retires to his own plot of territory. Even if a scrap develops no real 
wounds are inflicted. The unmated continues to show hostility to all 
comers (unless he is a very mature male experienced in sex and mate 
recognition) but gradually changes his mood if a female persists 
in visiting him. Once male and female have accepted each other the 
herring-gull pair recognise each other up to a distance of 30 yards 
apart; in view of this fact it is remarkable that the herring-gull is 
quite unable to distinguish between its own eggs and those (differing 
in pattern much more than male and female gull do in appearance) 
of another gull if given a choice test (Tinbergen^ i950' 

The mutual display of gulls has already been described (p. 170). 
It is generally considered however that the food-begging ceremony 
is performed more often by the female. In a typical instance the 
head is jerked up and down in front of the male's bill which may 
be actually struck or tapped thus imitating exactly the behaviour 
of the young bird. But much of courtship "feeding" is a mock affair, 
and often no food is transferred, probably because the male's stomach 
is empty, although the bills may be locked for a moment. Sometimes, 
in a crowded colony, a female may be "fed" by a second male; at 
all times the female appears anxious to beg food, even in winter. 
This must be derived from behaviour as a chick and a juvenile; 
for juveniles will beg food of any adult in winter, though rarely or 
never with success. This supplicating of the adults by immatures 
far from the breeding ground has given rise to the belief that the young 
bird remains attached to its parents long after the nesting season. 



THE GULLS 23I 

But this is not the case, as we shall demonstrate later. Billing and mock- 
or real feeding often precedes coition, which is conducted with much 
wing-flapping on the part of the male, as he maintains position, utter- 
ing a special loud deep note. Occasionally homosexual behaviour has 
been recorded (Noble & Wurm, 1943; Goethe, 1937). 

In mild western districts, where, as at Skokholm, pairing may begin 
even before the new year, mated herring-gulls may temporarily desert 
the breeding ground, and fly together to the feeding ground. But as 
spring approaches they are reluctant to leave the nest-site entirely, 
and once nest-building begins one or other of the pair remains at or 
near the focal point of the season's activities, especially in large colonies, 
where stimulation and competition is greater. This stimulation, as 
we have seen, may come from other species nesting close by. On 
many islands and some cliflfs two or three species of gull may nest 
together, and occasionally there is interbreeding (as between herring- 
gulls and lesser blackbacks) . But if there is stimulation between related 
species, there is no very visible interspecific competition. On Skok- 
holm and Skomer, for instance, great blackbacks and herring-gulls 
share the same plateau with much larger numbers of lesser black- 
backs, but each species selects a slightly diflferent ecological niche 
within the gullery. Thus the first two species are semi-resident, and 
lay their eggs at the end of April or the beginning of May, always 
selecting an outcrop of rock or a large stone against which the nest 
is constructed; the great blackback dominating the higher outcrops, 
the herring-gulls making use of rock- and loose-stone sites (which 
are available in plenty) on the lower terraces of the outcrops not 
occupied by the larger gull. The lesser blackbacks, arriving later 
(in February and March), and laying their eggs from 10 May onwards, 
use the ground between the outcrops, ground unencumbered except 
with low vegetation of wind-blown bracken, heather, Aiolinia, etc. On 
Skokholm there is probably enough room for all three; changes occur 
in the numbers of each species, but the total gull population tends to 
be more or less stable, and is kept from any great increase by the regular 
collection of eggs throughout May and June by lighthouse-keepers 
and others. 

The figures in the table (p. 232) are interesting as showing population 
trends. The great blackback is known to be an increasing species in 
the British Isles; at Skokholm the increase must come from outside 
sources, since here this gull has been prevented from rearing more than 
a very few young, by regular egg-collecting. Herring-gulls are able 



250 


300 


572 


700 


8o5 


350 


34 


55 


72 



232 SEA-BIRDS 

Census of Gulls at Skokholm {pairs breeding) 

1929 1939 1949 

Herring-gull 
Lesser blackback 
Great blackback 

Total pairs .. 984 1160 994 

(taken from Letters from Skokholm (Lockley 1947) and 1949 Skokholm Report) 

to rear proportionately more young per pair at Skokholm because 
many nest on inaccessible parts of the cliffs. The lesser blackbacks, 
nesting principally on the plateau of the island, suffer most from egg- 
collecting. It is probable that the gulls established their large main 
colonies during the years 1890 to 1920 when the island lay more or 
less abandoned and unfarmed (it was a prosperous farm one hundred 
years ago), and before the lighthouse was placed in commission. 805 
pairs in 1939 was a peak figure, and there has been a rapid decline since, 
groups and little colonies disappearing from inland sites, while more 
herring-gulls appear to have come inland to breed. But many factors 
must be taken into account in trying to arrive at the true reasons for 
the alterations which occur in sea-bird populations, especially in 
studying the dynamics of the gregarious and migratory lesser black- 
back, which is known to shift its breeding-grounds occasionally. 

At Hirsholmene in the Kattegat, Salomonsen ( 1947) found that 
there was a similar, and even more, competitive sequence in the place- 
ment of nests in three gull species nesting on the island. The black- 
headed gulls formed the nucleus of the colony by laying eggs first — • 
from 25 April onwards. A few common gulls, laying on i May, 
placed their nests in a ring around the closed territory of the black- 
heads. The smaller numbers of herring-gulls were also forced to breed 
on this perimeter. The arrival of the Sandwich terns, which lay on 
6 May, caused an upheaval due to the aggressiveness of the terns, 
which forced their way into the centre of the black-headed gulls, 
destroying eggs and driving the gulls away. Salomonsen suggests that 
the attachment of the Sandwich terns and the common gulls to the 
black-head colony may be due to the aggressive behaviour of the black- 
heads in successfully driving away crow, hawk, fox, stoat, etc.: 
also that the nesting drive of the terns is released by the sight of the 
breeding colony of black-headed gulls. Other species of terns and gulls 
are known to associate in breeding colonies; thus Sabine's gull 



THE GULLS 



233 




Fig. 40 

Breeding distribution of the ivory-gull, Pagophila 

eburnea 



{Xema sabini), nesting 
in swampy tundra along 
the arctic shore, is 
often found close to, 
or among breeding 
arctic terns. However, 
there are so many other 
factors to be considered, 
such as the relative 
abundance of each 
species from year to 
year (this appears to be 
unstable; in some years 
the terns do not re- 
appear in the old haunt), 
and the dominance of 
the species most suited 
to the environment. 
Palmer ( 1 94 1 ) even sug- 
gests that the presence 
of gulls is detrimental 

and eventually drives the terns away. The herring-gulls at Hirs- 
holmene were not in a typical environment. A numerous herring- 
gull colony, in a typical sloping cliff site or Baltic sand-dune, may 
dominate the breeding area to the virtual exclusion of all other gulls, 
as at Lambay Island cliffs, Ireland, where in 1939 we estimated 
10,000 pairs present, with only 40 pairs of lesser black-backs and 20 
of great black-backs. Such dominance can of course only occur in 
colonies at or near the centre of the geographical distribution in 
summer; thus on the edge of its distribution, in the Faeroe Islands, 
the herring-gull is a rare, shy and unaggressive species (Lockley, 1938). 
In the arctic the ivory-gull, Pagophila eburnea, is known as the ice- 
partridge or snow-bird, living as it does constantly in the vicinity of snow 
or ice, where its pure cream-white plumage matches its surroundings. 
It constructs a well-insulated nest of moss about 18 to 24 inches across 
and raised 6 to 9 inches above the ground ; but on cliffs a less elaborate 
structure may be built of more variable materials. The nests may be 
begun on snow- or ice-covered ledges. Two eggs are usually laid. 
The new-born chick is covered with a white down, which later becomes 
pearl grey; both colours are adaptively protective, the first matching 



234 



SEA-BIRDS 



the late spring snow and the 
latter the grey summer tundra. 
Clarke (1898) states that mor- 
tality may be heavy among 
the young ivory-gulls, many 
having been found dead in the 
nest, "their crania indented" 
from some avian attack (not 
improbably the ivory adults 
themselves? But see note on 
terns attacking gulls, p. 232). 

The ivory-gull is about the 
size of the common gull, but 
much more bold and aggressive. 
It must be one of the hardiest 
gulls in the world, since its 
southern boundaries of breed- 
ing distribution are more north- 
erly than those of any other 
bird (extreme north Greenland, 
east and north Spitsbergen, 
Franz Josef Land, probably 
Lonely and Bennett Islands, 
and in the Canadian arctic 
archipelago on Prince Patrick, 
Melville, north Baffin, and 
Ellesmere Islands; see Fig. 40). 
Under the circumstances it is not 
surprising that its habits have 
not been more than spasmodically studied. Even in winter the ivory-gull 
only reaches regions where other arctic birds summer — round the 
mainland shores of the Polar Basin. 

The beautiful Ross's or rosy gull, Rhodostethia rosea, with pale 
grey mantle and rose-flushed white head and breast, and neat neck- 
lace of black is one of the most mysterious birds of the world. For 
long the breeding-quarters of this species were unknown; as the 
Handbook says, "very few ornithologists have seen this gull alive." It is 
therefore worth giving the details of its strange distribution. 

The rosy gull was first discovered for science in June 1823 at Alagnak 
on the east side of Melville Peninsula in the central Canadian Arctic 




Fig. 41 
Distribution of the rosy, or Ross's 
gull, Rhodostethia rosea. Black line 
embraces breeding distribution; 
known breeding-places marked by 
stars. (Greenland once only.) Dots 
represent some sight and specimen 

records. 



THE GULLS 235 

by W. E. Parry's second expedition in search of a north-west passage. 
It was named (almost inadvertently) Larus roseus by William Mac- 
Gillivray in 1824 on one of the two specimens brought back by the 
expedition, and Larus Rossii by J. Richardson in 1832 (Swainson and 
Richardson, 1832). Richardson named it after James Clark Ross, who 
was one of Parry's lieutenants and who found it. MacGillivray gave 
it the English name of Ross's rosy gull, Richardson the cuneate- 
tailed gull. Moreover J. C. Ross, once more with that prince of polar 
explorers, Parry, was the first to find it in its real autumn and winter 
home, the sea-ice of the Polar Basin; he saw it north of Spitsbergen 
on the astonishing attempt to reach the Pole across the pack in July 
1827. 

Fifty years later Ross's gull was still only a legend in most parts 
of the world and less than a dozen specimens existed. Nobody had 
seen a flock, nobody (even at that time in Greenland) had seen or 
heard of a nest. It is possible to imagine the interest, then, when the 
American explorers in G. W. DeLong's Jeannette (imprisoned in the 
ice on 6 September 1879 and slowly drifting from the neighbourhood 
of Wrangel Island to that of the northernmost New Siberian Islands) 
met largish numbers of these very rare gulls over the east Siberian 
pack-ice. R. L. Newcomb, the naturalist, shot eight of them in 
October 1879. When the ill-fated ship foundered on 12-13 June 1881 
not far from Henrietta Island, the expedition salved its collections and 
journeyed in the ship's boats across the ice and 'leads' via Bennett- 
Island through the main New Siberian Islands across the Laptev 
Sea to the Siberian mainland at the Lena Delta. DeLong and many 
others died on the way; and all suffered terribly: but Newcomb kept 
three of his precious skins of Ross's gulls under his shirt during the 
long journey. 

Between 3 and 8 August 1894, almost exactly between the Lena 
Delta and the Pole, Nansen shot eight rosy gulls from the Fram^ more 
than ten months frozen in the pack. After Nansen had left the Fram^ 
and when he was (without at the time knowing it) about thirty miles 
north-east of Hvidtenland, the north-eastern group of the Franz Josef 
Archipelago, he and his companion Johansen began to see single 
adult rosy gulls on 11 July 1895, and continued to do so until they 
passed beyond this particular group on 8 August; sometimes the 
birds were in small flocks. They saw no more after that, as they 
travelled west and south through Franz Josef Land; indeed F. G. 
Jackson who by chance (!) encountered them, and gave them hospitality 



236^ SEA-BIRDS 

for the winter of 1896-97 in his camp in the south of the archipelago 
(at Cape Flora on Northbrook Island), only saw one in the whole of his 
three years stay — an adult on 5 July 1897. 

After Nansen had parted from the Fram its crew saw rosy gulls in 
the pack several times between 18 July and 11 August 1895. The 
furthest north record was at 84^41 N. So by the end of the century, 
then, it was clear that the species inhabited the pack north of Spits- 
bergen and Franz Josef Land. Further contemporary evidence of this 
came tragically to light in 1930, when the last diaries of S. A. Andree 
(who attempted the Pole by balloon) were discovered with his body 
on White Island, off the east of North-East Land, between it and Franz 
Josef Land. The log of the last struggles of Andree and his two compan- 
ions over the pack from their wrecked balloon two hundred miles to 
the northward contains at least fifteen and probably seventeen records 
of rosy gulls, seen between 25 July and 30 August 1897, from 190 to 
120 miles north of White Island. 

The secret of the breeding place was uncovered in the summer of 
1905, when S. A. Buturlin collected thirty-eight skins and thirty-six 
eggs of Rhodostethia rosea in the delta of the Kolyma River, which flows 
into the Polar Basin in eastern Siberia, east of the delta of the Lena 
River. He established that the mysterious rosy gull nested, not on 
the tundra, but in low marshy places, among alder-scrub, in the sub- 
alpine and wooded zones of the lower reaches of the rivers Alazeya, 
Indigirka and Kolyma, sometimes nearly a hundred miles south of 
the tree-line, and that it probably also nested westwards from this 
district to Swjatoi Nos, the promontory of Siberia opposite the New 
Siberian Islands. Buturlin's description (1906) of the rosy gulls nesting 
in the boggy moorland of this lonely country is a most vivid docu- 
ment, and well depicts the unexpected habitat of this extraordinary 
bird, which it shares with Hornemann's redpoll and the snow-bunting, 
the white-tailed eagle, the willow-grouse, the vega herring-gull and 
the arctic tern, the pectoral sandpiper, curlew-sandpiper, dunlin, 
grey and red-necked phalaropes, snipe, Asiatic golden plover, grey 
plover, ruff, the long-tailed duck, the white-front, the thick-billed 
bean-goose, and Bewick's swan, amongst others. 

Perhaps this huge area of the Siberian wastes is the sole reservoir 
of the rosy gull, which appears so promptly each September in the 
Eurasiatic arctic islands and on the Alaskan coast? If new breeding- 
grounds are still to be found, they are surely in other alder-scrub delta- 
floods of Siberian rivers, or perhaps (the possibility seems rather remote) 




Plate XXVIIa. Immature Glaucous Gull 

b. Immature Bonaparte's Gull 



J. D. RatUr 



Allan D. Cruickshank frotn \alional Audubon Society 



f 





w* 



Plate XXVII la. Little Gull, winter 



F. P. J. A ojyiiians -. 



b. Chicks of Yellow-legged Herring-Gull, Larus argentatus atlantis, Berlengas Island, 

Portugal 



R. M. Lockky 




THE GULLS 237 

in similar habitats in the Canadian north. The rosy gull breeds almost 
in a habitat suitable for Bonaparte's gull, yet does exactly the opposite 
in winter — goes north into what to a human is the most horrible area 
of the world, excepting the upland gale-swept below-zero ice of the 
antarctic continent. 

John Murdoch ( 1 885) found that Point Barrow, Alaska, was a main 
concentration point for rosy gulls between 28 September and 22 October 
1 881; he took "more . . . than there were before in all the museums 
of the world put together" and the birds were all moving north-east. 
He saw no more until the following 21 September, when they were 
again abundant. The neighbourhood of Barrow has remained an 
important fly way for rosy gulls; birds have been noted there in 
Septembers and Octobers ever since, always flying east. Charles D. 
Brower, who lived at Barrow until his death there in 1945, told A. M. 
Bailey (1948) that "a few are occasionally seen in the spring and they 
are irregular in the fall. However, thousands appear on gray days in 
September and October, always on a northwest wind. . . . They are 
excellent eating and often provide a welcome addition to our arctic 
fare. They come by thousands in the fall, and then suddenly disappear 
as quickly as they arrived, to be seen no more until the following year." 

Sabine's gull, Xema sabini, is as strikingly beautiful as the rosy gull, 
having a rich dark grey hood edged with a fine black line, forked tail, 
black primaries, pale grey mantle, and white triangle on the wings. 
In flight both gulls are, like the other arctic gull, the ivory-, graceful 
and tern-like. Sabine's was first discovered on the northern shores of 
Baffin's Bay, on what are now known as the Sabine Islands in Melville 
Bay, north-west Greenland, by E. Sabine on John Ross's first expedition 
in 1 818. (No ornithologist has visited these islands since.) The next 
example known to science was shot in Belfast Bay on 18 September 
1822. Since then Sabine's gull has been found to be a rare (though not 
rare in the way the rosy gull is rare) bird, breeding fairly widely in 
the High Arctic, and wintering somewhat mysteriously on the Pacific 
coasts of North and South America, and on the North Atlantic coasts. 
By 'somewhat mysteriously' we mean that the main wintering-place 
of the Atlantic population is not properly known, though it may well 
be largely in the Gulf of Gascony (in the Bay of Biscay). The main 
wintering-place of the Pacific population appears to be oflf the coast 
of Peru! Whether the Bay of Biscay really is a wintering-place remains 
to be proved; if it is, the birds seem to start their return passage 
early, before Christmas (as many petrels do), and nobody knows 



238 



SEA-BIRDS 




Fig 42 
a {Left) Breeding distribution of 
Sabine's gull, Xema sabini. In east 
Greenland and Spitsbergen it is 

sporadic 
b (Below) Breeding distribution of the 
kittiwake, Rissa tridactyla; black line 
encloses usual breeding range and 
black dots represent some known 
stations. Asterisks mark the three 
known breeding-stations of R. brevi- 
rostrisy the red-legged kittiwake. 




*In the nineteen-forties the following breeding-places were occupied (though not 
all in every year) : 

Scillies (Menavaur and Gorregan), Mainland Cornwall (Carn-les-Boel, Tol- 
pedn, Morvah, St. Agnes), Lundy, South Devon (Berry Head, Hopes Nose, 
Scabbacombe), Cumberland (St. Bee's Head), Northumberland (Fames, Dun- 
stanburgh. North Shields), Durham (Marsden), Yorkshire (Flamborough, Speeton, 
Filey, Bridhngton). In 1946 a pair laid eggs on a seaweed nest-drum on flat 
sand among a group of Sandwich terns on Scolt Head, Norfolk. 



THE GULLS 239 

where this passage takes place. Perhaps it is far at sea. Sabine's 
gull, like most high arctic breeders, nests late, and the few seen on 
spring passage have been mostly near their breeding-grounds in May 
and June. (In California the Pacific spring passage has not been 
observed before 7 April, and most birds have passed in late April 
and May — Grinnell and Miller, 1944). A. C. Bent (1921) gives no 
egg-date earlier than 28 May, and most in late June and early July. 
What happens to Sabine's gull between November and May? 

The romance of the discovery and the distribution of the rosy and 
Sabine's gulls has led us a little astray in this chapter on the life histories 
of the gulls; but owing to the inaccessibility of their homes in the 
arctic we know more about the first than the latter aspect of their 
lives. We must now go on to discuss another species, also arctic, but 
much better known. 

The kittiwake, Rissa tridactyla, is the most oceanic of all the gulls, 
if we except the ivory- and rosy gulls which range widely over the pack 
of the Arctic Ocean. But the kittiwake is a bird of the full Atlantic, 
and indeed operates over a wider area of the North Atlantic than any 
other sea-bird which breeds in it; for it goes a full ten degrees south 
of the normal range of the fulmar. It breeds almost as far north as the 
land goes; it is a pan-arctic breeder with penetrations into the temper- 
ate zone. In the Old World it breeds on very many arctic islands 
north of the Siberian coast, including most of the New Siberian Islands, 
Svernaya Zemlya, Novaya Zemlya and Waigatz, though not apparently 
Kolguev. As far as we can detect, it nests nowhere on the actual 
mainland between the eastern Chukchi Peninsula of Siberian Asia 
and the Murman coast. From the Murman coast along the Norwegian 
coast it nests on many steep cliffs islands south (until recently) as 
far as Rundo, on the corner of Norway between Alesund and Stat. 
It is a common breeder in Franz Josef Land, breeding on Rudolf 
Island, the northernmost, and on many others; in Spitsbergen it 
nests in thousands on many coastal cliffs, and it is extremely abundant 
on Jan Mayen and round Iceland. However, its only known colonies 
in East Greenland north of Angmagssalik are in Rafle Island at the 
entrance to Scoresby Sound and high in the north, Mallemukfjaellet 
in Kronprins Christians Land. It is vastly abundant in the Faeroes 
and in the northern and western isles of Britain, and common on many 
cliffs of Ireland, and some of Wales and the Isle of Man. In England 
it breeds in a limited number of stations — so few that they can be 
enumerated.* (footnote on facing page) 



240 SEA-BIRDS 

In the Channel Islands it was not known to nest until 1938, when 
Roderick Dobson found a small colony on Sark. The first colony in 
France was established on Tas de Pois in Brittany in about 1914, 
and there are now colonies in that province also at Toulinguet, 
Douarnenez, Prehel and Rouzic. 

The kittiwake has a purely arctic distribution in the Atlantic 
New World, apart from an isolated outpost breeding group in New- 
foundland and the Gulf of St. Lawrence whose colonies are on the 
same rocks as the gannet colonies of the New World, and a few others. 
There is a separated subspecies in the North Pacific (see fig. 42, above). 

From its habit of building its nest upon a very narrow ledge or 
foothold of rock on the side of a steep cliff, the kittiwake has little 
room to perform the more spacious ceremonies of the larger gulls, 
but much of the display is related to those expressions of the emotions 
in gulls already described. The kitti wake's note is shriller, yet softer 
and more pleasing to the human ear. It is, of course, traditionally 
rendered as "kitt-i-wake," and on the whole this must suffice, since it 
is extremely difficult to give satisfactory phonetic renderings of the 
cries of birds, at least on paper. Fortunately they have been captured 
for us extensively today by sound-recording specialists. 

Kittiwakes arrive at the breeding cliffs in pairs in late February 
and March (or April and May in arctic latitudes). They frequent 
the older nesting niches which become plastered with fresh droppings 
before the new nests are built. Often the last year's nest has been 
swept away by the heavy winter seas. But on the old site the paired 
birds stand close together, breasts inwards and touching the cliff 
face and each other. Frequently they break out into their mewing 
cries, which seem to have a contagious quality, and may spread 
rapidly through a colony until there is almost an uproar. Then 
suddenly all is silent for a short space, and the wash of the sea on the 
rocks below is loud by contrast. Small and dove-like, the kittiwake is 
attractive to watch as each pair is roused to affectionate exchanges; 
these consist of delightful movements, a graceful bowing, dipping, 
lifting, and waving of the head to the accompaniment of the excited 
mewing notes. The mouth is opened quite wide to show the orange- 
red interior, and the bill is used in fondling motions. At a later stage 
the male will place one foot upon the back or neck of the female, 
pawing her gently until she submits; he then climbs into position 
upon her back, but may rest there for a few moments before actual 
coition. During this time the female turns her head up towards his 




-f 




?"^~'£r 



1/. .", i), Lr 'III k\/iank from National A:. 



Plate XXIXa. Laughing Gulls 

b. Black-headed Gulls at nest 



Eric Hoski'i^ 





Plate XXXa {above). Gulls are above all scavengers. Here is a crowd of young and old 

birds (chiefly Herring-G ills and Lesser Black-backs) rushing to take oflfal at the fish wharf, 

Milford Haven {R. M. Lockky) . b {below left) Sabine's Gull, winter (Holland) {F. P. 3. Kooymans). 

c {below right) Black-headed Gull in winter plumage, Thames Estuary {R. M. Lockky) 



THE GULLS 24I 

solicitously. She also adopts the typical begging-for-food position, 
described for the other gulls. 

Gulls build nests from materials near at hand: of seaweed, grass, 
maritime plants, heather, lichen, etc. Bonaparte's gull [Larus Phila- 
delphia)^ and occasionally the black-headed gull, nest in trees. The 
great black-backed gull will decorate its nest with the remains of the 
carcases of its victims: shearwaters, puffins and auks. The black- 
headed gull uses rushes, sedges and small sticks; but individuals 
may make little or no nest, laying their eggs in a scrape in the ground. 
Kittiwakes form collecting parties, like gannets, and tear grass and 
herbage from the sides of cliffs ; they cement the nest together in its 
precarious situation by much treading with the feet, and they have been 
observed to carry mud-like material in their bills. Both sexes assist 
in nest construction; the male of the black-headed gull takes the 
initiative, doing much of the construction with material supplied 
by the female, but in some species the amount of nest building by 
each sex has not been fully ascertained owing to the difficulty of 
identifying the sexes in the field. 

The eggs of gulls are usually three in a clutch, and vaiy consider- 
ably in the shade of the brown, olive or greenish-blue ground colour, 
but all are spotted or blotched with darker brown or black. Although 
this colouring is protective and renders them inconspicuous at a 
distance, this advantage is somewhat lost by the conspicuous appearance 
of the head (white or dark brown) and white breast of the sitting adult; 
and also by the fact that when a large breeding colony of gulls is 
disturbed by man or other large mammal, the occupants rise in a 
screaming mass overhead, advertising the position and extent of the 
colony. This action does, however, divert attention from individual 
nests which are then partly protected by the drab camouflage colour 
of the eggs or chicks. However, as we have seen, unless disturbed by 
human beings or other formidable enemies, one or other of the pair 
remains at the nest, once the eggs are laid; and incubation may or 
may not begin with the laying of the first tgg. There is an interval, 
among the larger gulls, of at least one day between the laying of each 
tgg. Incubation is by both sexes, but apparently the female takes the 
greater share. As will be seen in the following table, the period varies 
between twenty and twenty-eight days. 

There is often severe loss of eggs and chicks occasioned through 
egg-collecting (for food) by humans, and raiding by dogs, foxes, 
otters, stoats, etc. Individual gulls, members of the colony, indulge 

R 



242 



SEA-BIRDS 

Incubation Periods of Gulls and Skuas 



MAX. WING-LENGTH CLUTCH INCUBATION 



Sabine's, Xema sabini 
Black-headed, Larus ridibundus 
Long-tailed skua, Stercorarius longicaudus 
KiTTiWAKE, Rissa tridactyla 
Arctic skua, Stercorarius parasiticus 
Common, Larus canus 
Great skua, Catharacta skua 
Lesser black-back, Larus fuscus 
Herring-, Larus argentatus 
Glaucous, Larus hyperboreus 
Great black-back, Larus marinus 



280 m.m. 


3 


23-26 days 


315 


3 


20-24 


320 


2 


23 


325 


2 


21-24 


328 


2 


24-28 


371 


3 


22-25 


415 


2 


28-30 


435 


3 


26-27 


450 


3 


25-27 


490 


3 


27-28 


510 


3 


27 



in cannibalism, by seizing and carrying off, or devouring at the nest, 
eggs and chicks left temporarily exposed by the absence of the owners 
or by the intrusion of visitors. In gannetries, great and lesser black- 
back and herring-gulls pounce on unguarded gannet eggs and small 
chicks; in gull colonies the same gulls seize and devour the eggs and 
chicks of their own as well as other species. When the eggs are lost 
from any of these causes the female will lay a second clutch after 11- 
12 days, provided the first clutch has not been long incubated. In 
colonies where regular egg-collecting takes place for human food 
(e.g. in black-headed, herring- and lesser black-backed gull colonies 
in the British Isles) fresh eggs are collected up to the beginning of 
July. If the eggs are taken as soon as laid the female gull is capable of 
protracted laying (Paludan, 1951), and egg-collectors assert that she 
will lay up to fifteen if each egg is collected during the twenty-four 
hours after laying; but that the nest-site may be changed during this 
long laying period. Many thousands of gulls' eggs, particularly 
those of the black-headed species, are collected and sent to large 
consumer centres, notably London, where they are more often than 
not sold as seasonal delicacies, and until recently were passed off as 
"plover eggs." 

So long as one tgg of the original clutch remains the female gull 
is content to continue incubation. Experiments have shown that a 
gull will brood almost any object which is only approximately the 
same size and shape as its own egg although some individuals are 
more discerning than others (see Kirkman 1937, pp. 82-99). Large 
gulleries in fact have been convenient grounds for several kinds of 
experiments. Kirkman moved the eggs from a black-headed gull's 




Fig. 43 
Breeding distribution of some dark-headed gulls: Lams pipixcan, Franklin's 
gull; Bonaparte's gull, L. Philadelphia; Mediterranean black-headed gull, 
L. melanocephalus {m.m.=melanocephalus melanocephalus ; m.r.=melanocephalus 
relictus) ; Brown-headed gull, L. brunneicephalus ; Saunders's gull, L. 
saundersi; White-eyed gull, L. leucophthalmus ; Grey-headed gull, L. cirrho- 
cephalus; Brown-hooded gull, L. macidipennis ; Andean gull, L. serranus; 
Laughing gull, L. atricilla. 



244 



SEA-BIRDS 



Fig. 44 

Breeding distribution of the little 

gull, Larus minutus (black line and 

dots), and of L. audouinii, Audouin's 

gull (stars) 




nest over distances of, 3, 4, 6 and 10 feet away. One bird sat on the 
eggs after each removal, and its mate sat on the empty nest. Some 
gulls were found by Kirkman to roll their own and other eggs back 
into the nest from a distance of 9-12 inches from the centre of the nest; 
this was a useful function when a gull's own eggs were retrieved, but 
became useless when the gull collected all the eggs placed within 
rolling reach (a distance varying between twelve and eighteen inches). 
The perception or intelligence of the birds in these experiments varied 
considerably. Paludan found that gulls rejected foreign eggs placed 
in an empty nest up to nine days before the laying of their own eggs. 
But from nine days before that event they accepted foreign eggs and 




Plate J. {above) Roseate tern. Britain is now the brccdiiig hcadquaiicrs of this rare 
species on the east side of the North Atlantic. {Veman Robertson) 
{below) Sandwich tern. A species that has increased in Britain during the 

present century, under protection. {Vernon Robertson) 



THE GULLS 245 

incubated them, and in some instances did not lay any eggs of their 
own. A skua will not recognise its own egg if this is placed outside the 
nest, but will devour it. 

Gulls are born with their eyes open, and are covered with a thick 
down. They are able to walk almost immediately. When danger 
threatens the Larus chick will leave the nest when it is only two days old 
and, at the alarm cry of the adults, will try to hide in some nearby 
crevice, or crouch under a tuft of herbage. At the age of five to six 
days and upwards it runs freely, and often in its haste to escape an 
enemy it will walk right over the edge of a cliff. This is a frequent 
cause of mortality when human beings walk about in gulleries. If 
the chicks drop from a great height they may be killed, but falling 
from lesser heights they may bounce unhurt from the rocks and boulders 
below ; if these are sufficiently shelving and tiered, they may be able 
gradually to climb back to the nesting site, by hooking themselves 
along with beak, legs and their unfeathered wings, encouraged by the 
calls of their parents — always provided they are not intercepted by 
some predator. In normal undisturbed conditions, however, the young 
Larus gull remains on or near the nest for a month to six weeks. 

The diet of the large Larus adults changes to one of small crabs, 
shrimps and fish when the young are first hatched. These are fed by 
both parents; at first the female has begged the male for food with 
which she has fed both herself and the chicks. The male brings in a 
crop loaded with food, and on the begging of his mate he regurgitates 
this in front of her. Frequently both adults and chicks will then pro- 
ceed to devour the salivated mass, the adults picking up and holding 
the food in the bill so that the chicks can feed more easily. As the chicks 
grow larger and stronger they themselves beg for food insistently, 
stretching up to tap the bill or peck the face of the parent newly 
arrived with a full crop. They show a definite reaction to bright objects 
by pecking. N. Tinbergen has proved that the red spot on the bill 
of the adult is a signal (releaser) to the young that food is ready. The 
occurrence of red on the bills of gulls and terns thus has a special 
significance; but other fish-eating species such as cormorants and 
gannets have no brightly coloured bill spot, although the young bird 
invites feeding by a similar tapping or pecking action. Young kitti- 
wakes, like young gannets, grope into the parental gullet for the regurg- 
itated fish. 

The manners of the young Larus gulls become more and more 
unruly, and they soon learn to snatch at the food before it has been 



246 SEA-BIRDS 

fully ejected and they quarrel among themselves for the best bits. 
The first hatched chick, being usually twenty-four hours or so older 
than the second, may sustain throughout the fledging period a physical 
dominance due to its ability to secure the lion's share. Where food is 
plentiful, however, the three chicks may eventually level up in growth 
and become indistinguishable from each other, but more often than 
not, one, and sometimes two, of the younger ones, disappear during 
the fledging period (this occurs in other species, e.g. the black guille- 
mot) . They have been underfed as a result of the greed of the first 
chick, and have become progressively weaker and less able to resist 
the bullying of the first-born. They die, or are eaten by their own kind, 
even by their parents who later may feed the partly digested carcase 
to the survivors. 

It is remarkable that in a large colony of gulls the number of chicks 
successfully fledged is probably, on the average, much less than one 
young bird to each pair of breeding adults. Where losses have not 
iDcen suffered as a result of depredations by man and other animals 
earher in the breeding season, and young chicks have hatched in 
fair numbers, great losses may occur as a result of adults preying upon 
the chicks of their neighbours. Probably the amount of cannibalism 
in any colony will depend on the abundance of normal fish-food. 
Kirkman found that young black-headed gull chicks which wander 
from home are sometimes adopted by chickless adults, but more often 
are killed by adults with chicks of their own. There is strong evidence 
that once a very young chick wanders from the nest it may not survive; 
even when it returns home it may be killed and eaten by its own 
parents. An example of this type of unreasoning cannibalism may 
occur when a nestling wanders away among burrows or nests of a 
species which is normally preyed upon by its parents. Moreau (1923) 
saw a herring-gull go to its own chick, which had strolled away 
among puffin burrows, and kill it with great ferocity. We have seen 
herring-gulls and lesser-black-backs attack chicks of their own species 
which were wandering among the nests of neighbours, and great black- 
backs killing and devouring new-born and up to half-grown chicks 
of the two smaller species. Such chicks are ruthlessly grabbed and 
battered to death. If small, a chick is swallowed whole, if well grown 
it is beaten until the bones are broken and the body is more or less 
shapeless; then it is gulped down in one mass, though often with 
difficulty. As a rule, after a heavy meal of this sort, the gull will rest 
for a while, looking very uncomfortable, and at first with the neck 



THE GULLS 247 

much swollen. The bulky mass passes slowly into the crop. An hour 
or so later it may be thrown up in front of the brother or sister of the 
murdered chick, which, however, cannot tackle such a gargantuan 
feast. The adult then usually re-devours the horrid mess. It may 
be that the cannibal throws up the meal less with a desire to feed its 
young, than to relieve its crop ; but if so, having relieved its crop, it is 
immediately hungry again and, after a further battering, the pulpy 
remains of the chick are swallowed once more. 

This cannibalism is prevalent among the great and lesser black- 
backed and herring-gulls, less so in the case of the black-headed 
gulls and the skuas, and apparently never occurs among kittiwakes. 

Glaucous gulls encourage their young in the art of egg-sucking 
as soon as they are able to wander and explore, or even in the nest. 
The adult breaks a hole in the egg (generally of some arctic-nesting 
duck) and the chick leisurely helps itself Later the fledged deserted 
gulls gather on the flat tracts along the tundra shore and feed on 
crow-berries {Empetrum nigrum), eating great quantities in default of 
other food. 

The picture of the sociable Larus gulls during the summer is hardly 
a pleasing one; they are shown, by human standards, to be disgusting 
and cannibalistic. The greatest mortality during the year must occur 
during the breeding season. That the powerful dominant gull lays two 
or three eggs each year in order to' maintain its numbers, while some 
weaker species which the gulls prey upon, such as certain auks and 
petrels, lay only one egg, is the more comprehensible if we regard 
cannibalism as an effective controlling factor in the population of larger 
gulleries. 

By comparison with the Larus gulls the kittiwake is as inoffensive 
in character as it is charming m appearance. It is true that at the 
nesting site it is noisy and a little quarrelsome, but this behaviour 
seems childlike and playful by contrast with the savage habits of the 
larger gulls. Probably the kittiwake has less opportunity to interfere 
with its neighbours, since each nest is usually isolated from the next, 
that is to say it is seldom connected by a bridge of rock over which it 
is possible for trespassers to walk. Contact between neighbouring 
nests can only be made by flying, and there is very little serious inter- 
ference by wandering or unattached birds. The kittiwake never preys 
upon the eggs of its own kind or of that of any other bird; it lives almost 
exclusively on small fish, crustaceans, plankton and molluscs taken 
upon or near the surface of the sea. But it often loses a large proportion 



248 SEA-BIRDS 

of its eggs and chicks to predators. Keighley & Lockley (1947), 
observing ten nests from 4 July to 1 4 August in Pembrokeshire, found 
that only two chicks eventually flew, the remaining fourteen eggs or 
chicks having been taken, one by one, by Lams gulls. 

In northern waters where its feeding grounds are close at hand, 
the kittiwake will occasionally nest on the ledges of buildings over- 
looking the sea. It frequently builds well inside caves, and, in the 
Arctic, on precipices some distance inland. A most unusual site is 
recorded by Salomonsen (1941c) on Tyrholm in the bird sanctuary 
of Hirsholmene in the Kattegat. In a colony of 2,902 pairs of black- 
headed gulls, 437 pairs of Sandwich terns, 6 of black guillemot and 
3 of common gull, were 1 1 pairs of kittiwakes, which had placed their 
nests on the ground, among boulders or in lyme-grass clumps, an 
interesting abnormality. It was found that the chicks in these kitti- 
wake nests made no attempt to run from them on the approach of 
human intruders, as Lams chicks do. The adults also remained at the 
nest, showing the typical cliff-nesting fearlessness. There is also a dune 
record for Britain (p. 238). 

The fledging-periods of most gulls are difficult to assess accurately 
since Lams chicks may wander from the nest for considerable distances 
before they become independent of the adults ; and the adults them- 
selves become less territorially minded at this stage, moving the 
"defended" area around the growing bird as the young bird itself 
moves, and gradually losing interest in the chick and its safekeeping. 
The age at which the young gull is able to fly for the first time may 
be reasonably considered its fledging period. But of this period sur- 
prisingly little appears to be known with certainty. The following 
figures therefore are estimates only: 

Estimated fledging-periods of Gulls and Skuas 
(mostly from Handbook) 

Black-headed gull (O. Heinroth) about 40 days 

Common gull do. ,, 30 

Herring-gull do. ,, 42 

British lesser black- back (R. H. Brown) ,, 32 

Great black-back (O. Heinroth) „ 50 

Kittiwake (F. C. R. Jourdain) „ 35 

Great skua (W. E. Glegg) „ 42-49 

Arctic skua (W. E. Glegg) „ 28-35 

Long-tailed skua (A. Pedersen) „ 21 



THE GULLS 249 

The great disparity between these figures cannot be due entirely 
to specific variations — there must be faulty estimating. This is indicated 
when we compare the above estimate for the kittiwake by Jourdain 
with two accurate records of the fledging period of this species : 44 and 
45 days (Keighley and Lockley, 1947). There is plenty of room for 
more exact observation. 

Literature dealing with the period between the time when the 
gull chicks are fledged and their dispersal to winter quarters is scanty. 
At Skokholm, Lockley (1947) found that the adult great black-backs, 
the lesser black-backs and the herring-gulls gradually left the island 
in August, September and October, and a small number of the fully 
fledged young gulls appeared to leave at the same time. But many of 
these juveniles were left behind, and there were periods when the 
island held about one hundred juveniles and few or no adults. In 
calm weather these juveniles managed to get a living by wandering 
about the island picking food from the surface of the land, including 
food obtained from the carcases of dead puffins, shearwaters and rabbits, 
and along the tide-line. But in stormy weather, which was frequent 
in autumn, many of the young gulls whose powers of flight seemed 
feeble, would remain in a loose flock in the centre of the island, 
mewing a great deal as if hungry, but unwilling to fly in search of 
food. It was found that many of these birds were thin and generally 
in very poor condition ; and if the weather continued rough some of 
them died or grew so feeble that they could easily be run down and 
caught in the open. 

Comparative figures from other gulleries reveal that an extremely 
small proportion of chicks is raised each season, due to egg-stealing, 
cannibalism, and other factors, including rough weather at fledging 
time. Paludan (1951) records only 20% chicks fledged in herring- 
gulls and 5% in lesser black-backs on an island near Bornholm in the 
Baltic. The possibility of disease attacking young gulls in crowded 
colonies should also be borne in mind; it may have been the cause of 
the enfeeblement of so many of the young gulls at Skokholm, where, 
in August 1947, three juvenile herring-gulls died after a few days of 
sickness. Examination of the corpses revealed that all three had 
blistered feet, a characteristic feature of an epizootic which has caused 
the death of many juvenile Manx shearwaters in the autumn on Skomer 
and Skokholm (Surrey-Dane, 1948). 

It is doubtful if juvenile gulls remain attached to the adults for 
long in the autumn. They do, however, frequently follow adults. 



250 SEA-BIRDS 

calling querulously for food, and an adult which happens to have its 
crop full of food may respond to the persistent begging of a juvenile, 
not necessarily its own child. The young gulls, like many other juvenile 
sea-birds, drift away from the breeding ground on their migration 
route, independent of the adults. The lesser black-backs travel farthest 
— as far south as the Iberian peninsula and North Africa. Many of 
these migrants remain in waters about the southern limit of their 
winter range until full adult plumage is acquired during their fourth 
year. They may be seen about the harbours of Portugal and the Bay 
of Biscay. Few return to their breeding grounds with incomplete 
adult plumage. But the juveniles of glaucous, great black-backs and 
herring-gulls do not travel far from their breeding coasts, although there 
is a general local southward trend; the majority remain within a few 
hundred miles of their birth-place. The adults are even more sedentary 
than the juveniles. During adolescence gulls of sedentary species will 
frequent harbours and estuaries the whole year round, but a few of 
the older ones, whose plumage is nearly mature, may visit in summer 
those breeding grounds which lie within easy flight of these feeding 
grounds. 

The complete moult takes place in autumn, and a second moult, 
of the body feathers only, occurs early in the spring, when the streaky 
winter appearance of the adult head and neck is replaced by pure 
white, or, in the brown-headed species, by the t}^ical dark hood. 
The smaller gulls, e.g. the black-headed, common and kittiwake 
species, acquire the mature plumage after their second winter, one 
or two years in advance of the large Larus gulls. 



CHAPTER 12 

TERNS AND SKIMMERS 



THE FORTY-TWO SPECIES in the subfamily Larinae/ or gulls, are 
fundamentally northerly in their present distribution, and probable 
evolutionary origin. The thirty-nine species in the other big subfamily of 
the Laridae, the Sterninae or terns, are fundamentally tropical, and 
there are more (thirty) species in the Pacific than in any other 
comparable region of the world. However, there are a good number 
in the Atlantic — twenty-three, or twenty-five if we include the Mediter- 
ranean with it, and it is certainly not possible to conclude from the 
•relative number of species that the Pacific is the evolutionary home of 
terns; but it is likely that the adaptive radiation and evolution of the 
terns has mainly taken place in the tropics. No less than nineteen 
species breed on or near the shores of the smallest of the warm oceans, 
the Indian Ocean. Seventeen species breed round the borders of the 
North Atlantic. The breeding-distribution of only two species, 
the arctic tern Sterna paradisaea and the common tern S. hirundo^ crosses 
the Arctic Circle — that of the latter only in one small region. However, 
four species breed in the cool climate of the cold waters of the Ant- 
arctic Ocean. Many terns are birds of rivers or inland marshes — 
nine species breed inland in Eurasia, six in North America, five in the 
Indian region, and several inland in Africa, Australia and South 
America. Some, like the black-bellied tern Sterna melanogaster of India, 
Burma and Ceylon, or the common river-tern S. aurantia, which has a 
rather wider distribution in the same region, or the yellow-billed tern 
S. superciliaris of S. America, are exclusively, or almost exclusively 
inland species. Others, on the other hand, like the noddy and fairy 
terns (Procelsterna, Anoiis and Gygis) and the sooty tern Sterna fuscata 
have very wide and very oceanic distributions, and many other Sterna 
terns work into the pelagic and oceanic zones of the world's seas. 
The majority of terns are white with, in spring, a black crown and a 
grey back; a minority are darker, especially the less marine species. 



252 SEA-BIRDS 

The terns, like the gulls, may be divided conveniently into these two 
categories: one containing the strictly marine species, nesting largely 
on sand, shingle or rock, and chiefly white, with grey back and 
black crown; and the other containing those species, some of them 
black or black-winged, and black-backed, which nest on salt- or 
fresh- water marshes. The latter in the North Atlantic region include 
the gull-billed tern Gelochelidon nilotica, Caspian tern Hydroprogne 
caspia, Forster's tern Sterna forsteri, black tern Chlidonias nigra, whiskered 
tern C. hybrida, and white-winged black tern C. leucopterus. 

Terns are gull-like in their habits, but their longer wings and long, 
usually forked, tails, give them a distinctive appearance. Their flight 
is more buoyant and graceful. Because the wings appear to pass 
through a greater arc in their slow measured beating, the flight may 
not seem so effortless, and it is also less gliding than that of the gulls. 
The general impression is of a light hovering progress, and the synonym 
"sea-swallow," often applied to the tern, is only appropriate in as far 
as the long wings and tail of the tern resemble those of the swallow. 

Terns were formerly killed for the millinery trade, but are now 
protected in English-speaking countries. As already described in 
chapter 3, p. 84 the little tern was taken in "incredible numbers" and 
almost exterminated along the eastern U.S. coast by collectors for 
this trade, in Audubon's time. From about 1800, for nearly a hundred 
years, the feathers of this tern and many other species of birds, includ- 
ing the roseate tern, were in demand, wings and whole skins being 
used to decorate women's hats. 

All terns are considerable migrants, the arctic tern (see p. 142) 
greatest of all, breeding as far north as there is land in the Arctic, 
and migrating as far south as there is open water in the Antarctic; 
in both polar seas arctic terns may fish among pack-ice, and rest on 
ice-floes head to wind, especially in their antarctic winter quarters 
(Falla, 1937). Thus, although they are called arctic terns, these birds 
enjoy more hours of daylight (eight summer months in the year) 
than the tropical species, by wintering in the southern summer. The 
majority of terns arrive at their breeding ground later than the gulls. 
The vanguard appear in March in the British Isles, with main arrivals 
in April and May; but they may be a month or six weeks later in the 
High Arctic. Like gulls, they roost at first away from the actual nesting 
site, only settling down to sleep in the breeding ground a few days 
before the eggs are laid. As the sexes are superficially alike it has not 
yet been established whether the single birds which are sometimes seen 



■*•»!- 









» -- ^ 



V^. 





Plate 6a. Little tern on eggs — a sand-and-.shingle-baiik. nester. uohn Markimm) 
b. Black tern on eggs — -a marsh-land nester. {Erie Ihsking) 



TERNS AND SKIMMERS 253 

to arrive first are males; but sometimes it is a pair that is first seen, 
or a flock. 

In general, terns are extremely capricious, nervous, and sociable; 
these characteristics are shown in erratic movements, and in sudden 
changing of a breeding site. A colony may be apparently fully 
occupied, and often nests built up to the middle of May; then the 
majority of the flock may suddenly leave the site and settle on a 
new one, perhaps several miles away. In that case the few which have 
started to breed may forsake their nests and eggs in order to join the 
main colony, rather than continue in isolation. They are most successful 
as breeders only when able to nest in large numbers close together. 
Like other species of sea-birds terns seem to require this stimulation 
of numbers. It is for this reason, it is suggested, that they will settle 
down in an already advanced breeding colony of gulls or related 
species, causing considerable disturbance and even driving away the 
original gull colonists by their aggressive behaviour (see p. 232). 
But A. O. Gross (1951) states that herring-gulls drive out terns (Massa- 
chusetts) ; and Palmer (1941) observes that "when a gull species nests 
in great numbers close to a tern colony, the terns usually go elsewhere 
eventually." Sandwich terns were found by Salomonsen to dominate 
black-headed gulls, and royal terns are known to boss black skim- 
mers. Among marsh-terns, the black tern is bold and domineering 
inland in North America (Bent). Other terns live socially in harmony: 
as sooty and bridled terns; and common, arctic and roseate terns. 
This harmony is generally due to differing ecological requirements. 
Austin (1929) points out a possible ecological relationship in a 
mixed ternery: the roseate tern has comparatively long legs, adapted 
for walking about and nesting in fairly long grass; the common 
tern with shorter legs prefers barer ground to walk upon; the arctic 
tern with very short legs hardly walks at all and nests as a rule on 
vegetationless ground. (In the Faeroes, however, the arctic tern, 
with no competition from other species, nests freely in low annual 
vegetation and grass.) Social stimulation and its significance in the 
reproductive cycle of sea-birds has been discussed in chapter 7. 

Salomonsen (1943) found that large colonies of common terns start 
laying and hatching earlier than smaller ones; but he found that 
"the difference is only slight" — which might reasonably be expected 
of terns, with their habit of arriving late, simultaneously, and ready 
to breed. 

The breeding habits of terns have been intensively studied by 



254 SEA-BIRDS 

Watson (1908), Tinbergen (1931), G. & A. Marples (1934), Palmer 
(1941), and others. The Marples observed that "a tendency for the 
birds to fly in pairs while on migration rather points to a permanent 
union;" and these indications of permanent matings are recorded by 
other observers, including Palmer. Terns may however often be seen 
travelling singly, and the migrating flock does not appear to consist 
of paired birds; it may be that these records of two, four, six, etc, 
terns in flight are only coincidental signs of normal sociability, out 
of the breeding season. 

The fish and crustacean food of terns is secured either by diving, 
or by snatching without actually wetting the plumage as the bird 
skims over the water. Terns can swim, but do not do so verv much — 
or very well; and if confined in a glass-sided water tank without a 
resting place will drown. When hunting for food the tern quarters 
the surface, its head down and beak vertical, like the fishing gannet. 
In diving it drops like a stone, wings closing as it descends; but it 
makes much less splash than the gannet, being smaller, and also 
usually diving from a lesser height. Terns are skilful fishers, pausing 
in mid-air and hovering until sure of a successful strike. Some species 
submerge partly or completely (royal. Sandwich, common, roseate, 
arctic, Caspian, and little terns); other species (black, whiskered, 
white-winged black, gull-billed, sooty, bridled and noddy terns, 
and black skimmer) do not dive, or dive but rarely. Noddy terns catch 
minnows as these jump clear of the surface of the sea. Skimmers, feed- 
ing at night, are even more specialised; they plough the surface with 
the long lower mandible, and by so doing they attract small fish to 
the moving phosphorescent water. The skimmer then turns back and, 
flying over the disturbed area, snatches and scoops up the shrimps 
and small fish which are attracted to the glistening track. Some 
terns, including the skimmer, occasionally wade in shallow water in 
search of food. 

The captured fish or shrimps, etc., may be swallowed immediately, 
as the diving tern rises, and, with a shivering motion of the wings, 
shakes the drops of water from its plumage ; or larger fish may be held 
in the bill for the lengthy display ceremony described below, or may 
be carried to mate or chicks. In the majority of cases the fish is carried 
hanging down on the left side of the bill, although there appears to 
be no ready explanation of this custom. Fish-carrying is sometimes 
disadvantageous, as when skuas are about, which force terns to drop 
their catches. 



TERNS AND SKIMMERS 255 

The marsh-terns feed mainly on aquatic insects, such as beetles, 
flies, dragon-flies, spiders, etc., as well as tadpoles and small fish. 
They will hawk for insects over the land, like swallows. The sea-terns 
catch insects, beetles, etc., on the wing, especially in cold windy weather 
when marine food is difficult to obtain. Forster's tern, a bird of the 
northern marshes of the New W'orld, arrives on the newly unfrozen 
grounds in time to feed on the numerous dead fish, insects and amphibia 
released on the melting of the winter ice. 

The visitor to the sea-ternery in the early summer will immedi- 
ately note the typical "fish-flight." One bird, which may be the male 
or the female, flies circling about the colony with a fish in its beak, 
calling loudly with the characteristic grating tern cry which is not 
unlike the sound produced by a wooden stick drawn rapidly over 
serrated metal. The other bird usually flies in front of its partner 
carrying the fish. The foremost bird flies with its neck stretched out; 
the bird with the fish has its head bent down. The pair may settle and 
the fish may be exchanged, the bird receiving the fish immediately 
flying up and performing the same actions, preceded by its partner 
leading the way with outstretched neck or one flier may be joined 
by another and suddenly both will rise steeply into the sky, and 
presently make a long glide to earth. 

A tern carrying fish almost invariably screams with excitement, 
and it seems as if the fish in the bill is an essential part of the emotional 
display used by terns. Tinbergen considers that the male may carry 
the fish in flight over the ternery when he is seeking a mate. Many 
variations in the "fish-flight" occur. Sometimes strange birds pursue 
the bird with the fish, and make ineffectual attempts to snatch it. 
Other chases occur without fish. There is also a curious gliding flight 
and a circling high over the colony, with darting downward rushes 
at great speed. The abnormally slow, lazy, deliberate beating of the 
wings ("butterfly flight"), recorded of other sea-birds (e.g. the auks), 
is not uncommon, and appears to have a social as well as a sexual 
significance: Palmer (1941) considers that it results from an attempt 
to carry out normal display in the air; it is often concluded by a 
delaying of the folding of the wings on alighting near another tern. 

The pre-courtship of terns at the nest-site follows the pattern of the 
gulls and many other birds. The overall sexual bond has attracted 
the female towards a male in possession of a scrape in the ground; 
but in order to keep this territory and win a mate he must peck at 
and assert his dominance over all comers. Palmer considers that the 



256 SEA-BIRDS 

unmated tern can only discover the sex of another tern by testing its 
reactions: if it submits to pecking it is female; if it fights it is a male. 
The female, desiring to occupy a scrape, soon submits. After this 
"ground recognition test," the two birds are mated for the season, 
and recognise each other at some distance. But the dominance of 
the male is kept up throughout the nesting season (Palmer). If an 
intruder is a male the owner of the scrape must drive the visitor away, 
or risk losing the territory. Even the arrival of the partner at the nest 
immediately sets up this ceremony, or a modified form of it. The 
bird at home is excited by the appearance of another from out of 
the sky — excited and at first probably suspicious, in spite of visual 
or vocal recognition — and so some form of greeting ceremony is 
performed before all is quiet between the pair. These formalities are 
instinctive, usually beginning with threat display which is then changed 
to the opposite — invitatory or sexual movements, which serve as outlets 
for the thwarted fighting instinct. These nest-visit ceremonies happen, 
of course, in many other organisms ; in some birds, such as the herons, 
they are quite elaborate and prolonged before the arriving bird is 
able to relieve the bird in possession. 

Males, presumably unattached, sometimes visit occupied nests 
and, encountering opposition, fight quite fiercely; and eggs may 
be broken or rolled out of a nest as a result. In courtship the male 
noddy invites the female, by nodding his head (hence perhaps the 
name), to take the fish from his bill. This is characteristic of the sea- 
terns. The female may accept and then return it to her mate; or, 
more rarely, eat it. The pair may walk side by side in what the Marples 
call "the parade." This is not unlike the action of the farmyard cock 
soliciting the hen, and it has the same stimulatory function of promoting 
hormonic activity and so releasing sexual desire. The cock pivots 
round the hen, who pivots to face the performer. But the aggressive 
pecking is over: as sexual excitement increases the head and tail are 
raised at a sharp angle, the head being lowered again in a bowing 
movement, displaying the hackles of the handsome nuptial cap. 
Coition is initiated by the female crouching with her head down. 
The cock may stand on the hen's back for some time, perhaps to be 
interrupted by a neighbouring bird who has likewise been stimulated 
by these attitudes. 

Nests are made rapidly and simply, by scraping in the sand or 
shingle, or by adopting a depression in the rocks. In the sand the bird 
falls forward on its breast and scratches backwards with its feet. 



^M^ 



Plate XXXIa. Common Gulls, summer plumage 



h. Eggs of Gull-billed Tern 



1 




C. A. Gibson-Hill 



F. P. y. Kooymans 



N 



u 



45/ 




— - ^ < . 

>. ^ ,r ^ ^ 

^ I- C - 
be Z. 



1= '^ 



Rj 



(^ .BU 



TERNS AND SKIMMERS 257 

pirouetting in a perfect circle. If there is no nesting material handy, 
within a few yards, a nest may not be lined at all. The Marples made 
interesting experiments in which they proved that the lining of the 
nest (with a variety of material) depends entirely upon what is avail- 
able in the immediate environment. Birds which were incubating 
eggs in shallow scrapes in the sand, with no nest lining whatsoever, 
at once built a substantial rampart around the eggs when material 
(scraps of jetsam) was placed within a few feet of the scrape. They 
also proved that terns have a very precise sense of geographical position. 
When the Marples buried the nest so that the site could not be dis- 
tinguished from a wide environment of smoothed-over sand, the owner 
of the nest alighted above the hidden eggs, quickly dug down, dis- 
covered the eggs, and brooded them after scratching them clear of 
sand. Nor were terns deceived by extraneous alterations to the 
environment of the nest, even when the nest was again buried in sand. 
Other experiments showed that when a nest was moved fifteen feet 
away from high tide, the owner found it, in its new position, after only 
a little hesitation. Terns would also follow their nests for a consider- 
able distance if they were moved a few feet at a time. When the eggs 
of terns were painted in various bright colours (terns accepted eggs 
painted bright yellow, but were somewhat put off when the eggs 
were painted bright red or blue), or their shape altered by the addition 
of plasticine, the owner would peck at the eggs as if to test their 
genuineness, after which it would settle to brood as if nothing had 
happened. In these experiments the terns showed themselves more 
perceptive and tolerant than gulls. This perception is perhaps under- 
standable in a species nesting so close to the edge of the sea: high 
tides may flood the nesting area at times, or at least change the super- 
ficial environment, by depositing seaweed and jetsam, or by altering 
the contours of pebbles and sand; and so an ability to deal with these 
hazards is important for the tern's survival. The ability to defend 
the nest against shifting sand on windy days is probably instinctive. 
When storms blow the brooding bird will constantly scratch accumu- 
lating sand away from the nest, or will protect the young chick by 
nursing it carefully, so long as the sand is on the move. 

Incubation is by both sexes, but the female is believed to take 
the larger share. With most species, incubation begins with the first 
egg. There are generally three, sometimes two, and less often four eggs 
laid at intervals of about forty-eight hours. Nests have been recorded 
with up to ten eggs, but the Marples have shown that where nests 




Fig. 45 
Distribution of the Sandwich (Cabot's) tern, Thalasseus sandvicensis. Black 
lines embrace breeding range; black dots are some sight or specimen 

records. 



are placed (artificially) too close together, a dominant female on one 
nest will rob a neighbouring nest by rolling the eggs from it into her 
own; but she is unable successfully to hatch more than the normal 
clutch against her brooding patch. Coition, which takes place on the 
nest, continues after egg-laying, but it slows down, and the male 
may rest for longer periods on the back of the female and finally step 
down without actual consummation. He appears to be an anxious 
and fussy husband, displaying vigorously as he brings fish to feed his 
sitting mate; but she also feeds him when he takes his turn on the 
nest. As in other sea-birds mutual display continues, in lessening 
degree, during the incubation and fledging periods. 

The eggs are much like those of the gulls, with ground-colour 
varying from pale grey to a dark brown, streaked and spotted with 
still darker greys and browns. Blue eggs, with or without markings, 
occur, but the erythristic type is not common. The incubation period 



TERNS AND SKIMMERS 



259 



Fig. 46 
Breeding distribution of the little 
(least) tern, Sterna albifrons. Black 
lines embrace probable extent of 
breeding-range; black dots represent 
some known breeding-places 




260 SEA-BIRDS 

seems to vary considerably, with a minimum of 21 days. The new- 
born chick is covered with a long soft down with fine hair-like tips, 
and is protectively coloured: the background of the down is some 
shade of buff, marked and streaked with patterns of black and brown. 
Terns will lay a second clutch if the first one is lost, or abandoned by 
a shift of the whole colony, and a third if a second is freshly taken. 
Black terns in North America lay three clutches (of 3, i, i) if con- 
tinuously robbed. Little terns in South California are said to raise 
two broods in a season. 

The Marples record that the greatest anxiety of the adult at hatch- 
ing time is to remove the egg-shell as soon as the young bird is free, 
and to carry the shell off and drop it at a distance ; they argue that 
the female does this instinctively, but by so doing she "removes, one 
after the other, the evidence of the birth of her offspring, and this 
was presumably to protect them from danger, for the presence of the 
shells would draw attention to the nests." 

Young terns have a peculiar shrill chittering, squealing or whistling 
note, which they use until they are well on the wing. They are brooded 
in the nest for the first two or three days by the female, the male 
feeding both his mate and his chicks during this period. Both parents 
feed the chicks subsequently, bringing in sand-eels — among the princi- 
pal food of the Atlantic sea- terns. When one parent is feeding the chicks 
the other often appears to mount guard, driving away neighbours 
which approach too near. When handing over a fish to its mate or 
chick, the adult always places it head first in the other's bill. It is 
never dropped, except occasionally, on the ground. If it does fall 
to the ground the adult may pick it up again, but the chick seems 
incapable of doing this, and many fish will be found lying about on 
the ground in a ternery, with the young terns, oblivious of this food 
at their feet, calling hungrily to be fed. Young terns will swallow 
fish of greater length than their own bodies, and will gulp uncomfort- 
ably for a long time with the tail hanging from the mouth while the 
head is being digested in the stomach. The old tern thrusts the fish 
only sufficiently far into the mouth of the young tern for the throat 
muscles to grip it. On hot days the adult may provide shade for the 
chicks by partly opening its wings, but for short periods. Chicks not 
provided with shade have been known to die from heat upon sand 
(Austin, 1932b). 

In some cold stormy summers there is great mortality among 
young terns, due to lack of food and to the dangers from drifting sand 




m 



^v^\ 




-^ > •• ■■pi' . ^i«t^t 





F. P. J'. Kooymi 



Plate XXXIIIa. Little Tern, Holland 



b. Black Tern, autumn plumage 



Eric Hosk. 




\ 




'"•Iw^fefc, 



.^ ^ -^fv-iZ' 



9^^ 



;*r 



^: 



■^ 



,^*«*^« 



»-.>^-^. 



Plate XXXIV a. Common Terns mating 

h. Caspian Tern, Hat Island, Lake Michigan, U.S.A. 



C. A. Gibson-Hill 



Roger T. Peterson 




'- x>- 'y-^^^t'^- 









TERNS AND SKIMMERS 261 

and wind which may blow the chicks about or bury them when they 
are in a weak condition. Sudden violent thunderstorms with torrential 
rain may kill many. In America snakes and owls prey upon chicks, 
and elsewhere foxes and rats are predators. 

Under normal conditions, however, the chicks grow rapidly, and 
begin to fly when they are about a month old. When they are undis- 
turbed by trespassing man and mammals, the chicks remain close to 
the nesting site. But if disturbed they are apt to gather into dense 
flocks which wander or are driven about the ternery, causing great 
anxiety to the crowd of adults flying above them. It is a matter of 
wonder to the observer that the chicks ever sort themselves out and 
are claimed again by their parents. It may well be that, as with the 
penguin and the guillemot, the lost tern chick is able successfully to 
beg food from other adults than its parents, but this has not been 
actually proved. Most observers agree that there is voice recognition 
between the adults and their own young at an early stage in the 
rearing period. 

Incubation and Fledging Periods of Terns 

Black tern, Chlidonias nigra 
Gull-billed, Gelochelidon nilotica 
Caspian, Hydroprogne caspia 
Sandwich, Thalasseus sandvicensis 
Roseate, Sterna dougallii 
Common, Sterna hirundo 
Arctic, Sterna paradisaea 
Little, Sterna albifrons 
Sooty, Sterna fuscata 

(From the Handbook of British Birds , with corrections) 

The marsh-terns have not been so thoroughly studied. As far as 
we know their breeding habits do not differ very substantially from 
those of the sea-terns. The small marsh-terns (e.g. the black, white- 
winged black and the whiskered terns) frequently build their nests on 
floating heaps of water-weeds, but more often among rough herbage 
in marshy ground. Apparently the incubation periods in the smaller 
marsh-terns are shorter than in the sea-terns. 

In Britain the black tern has had an unfortunate history, for since 
the year 1885 it has been probably quite extinct as a breeding species, 
except for an interlude in 1941-42. It is an example of the effect man 
can have on a species by altering its habitat. Formerly it nested mainly, 



Incubation 
14-17 days 
22-23 
20-22 


Fledging 
21-28 days 
28-35 
28-35 


21- 

23 
22- 


.24 

■25 
26 


35 
28 
28 


21- 


22 


21-28 


19. 


•22 


28 


26 




30-35 



262 SEA-BIRDS 

if not solely, in the fenlands draining to the Wash, in the Norfolk 
and Suffolk broads, and in Romney Marsh in Kent. From all of these 
places (fig 48, p. 265) it appears to have been driven by drainage 
and reclamation. 

Its reappearance as a breeding-species in Britain was discovered 
by R. Cooke (1946) at Pett Level near Winchelsea in Sussex, on an 
area of a thousand acres that was submerged as part of the invasion 
defences. On 10 June 1941 he found eight occupied nests on an 
island formed by a collection of stranded debris. In 1942 five pairs 
returned to the island, and young were safely hatched; but in 1943 
only seven individuals arrived, were much disturbed by black-headed 
gulls, and did not nest, and in 1944 the area was once more drained. 
Since then no black tern has laid in Britain, though it would seem that 
the broads and coastal marshes of Norfolk and Suffolk, now most 
thoroughly administered as sanctuaries and for the preservation of 
marshland habitats, are ready once more to provide the species with 
a home. 

The sooty, noddy and bridled terns are more oceanic in their 
habits, breeding on remote islands and reefs, and fishing far out at 
sea. According to G. H. Wilkins (1923) sooties may feed as far as 200 
miles from their breeding place. Their pelagic habit has caused differ- 
ences in the routine of the breeding season; thus the incubation period 
is shared in much longer shifts, according to Watson (1908): each 
noddy tern sits for twenty-four hours, changing over at night; and 
the incubating bird is fed by its mate. The clutch is normally only one 

The black skimmer [Rynchops nigra) is a black-backed red-footed 
tern with specialised crepuscular feeding habits already described. 
Rather clumsy and stupid at their breeding grounds, skimmers may 
be persecuted by the nimble and powerful royal terns in search of 
desirable nesting territory. The royal terns scratch for themselves a 
home in the heart of the black skimmer colony, covering the skimmers' 
eggs with sand or vigorously kicking them aside while the helpless 
owners look on. Young skimmers are able to half-bury themselves 
in sand by wriggling and scratching a hollow with a few vigorous 
leg-movements. They show a "marked instinct of recognising parents' 
raucous cries" (Bent, 1921). The peculiar long lower mandible is not 
fully developed until the chick is able to fly. 

The nervousness of terns and their high excitability, higher than 
that of the sociable gulls which are also subject to mass "alarms and 



TERNS AND SKIMMERS 263 

silences" (e.g. black-headed, lesser black-backed and kittiwake gulls), 
is expressed in what the Marples call "dreads" and "panics." These 
are distinct from the ordinary alarm when the sitting bird leaves the 
nest, flies into the air for a short time, calling loudly, and then returns 
quickly to the nest. "Dreads" and "panics" are characterised in all 
the sociable terns at their nesting grounds by a sudden rise in the normal 
clamour of the breeding group. It is succeeded by the whole colony 
rising and sweeping away in a compact flock in complete silence, 
only to return in a short time and resume their normal behaviour. 
The movement appears to be so regimented that the observer could 
believe that a command had been simultaneously obeyed. Although 
dreads and panics apparently occur as a result of the visit of a human 
being to the ternery, they have frequently been witnessed from a 
long-established hide; therefore they cannot be considered solely due 
to human agency — often they appear to be caused by no external 
disturbance whatsoever. 

Tinbergen attributes the dread to a temporary re-assertion of the 
flocking instinct, as against the dominant reproductive instinct. 
Sometimes a flock will rise and hover over the body of a dead or 
wounded companion; and perhaps afterwards attack it for awhile. 
Sometimes only part of the ternery is affected by a dread. Sometimes 
it is a flock of one species only that rises from a large ternery, thus 
revealing the position of that specific colony. It appears that there 
may be one individual which constantly starts and leads a dread. 
The panic is a variation of the dread, according to the Marples, who 
give this name to the sudden dashing about in the air of a group of 
terns which afterwards zig-zag rapidly to earth or water in complete 
silence, immediately flying back to the colony as noisily as usual. 
Of the sea-terns only the little tern appears to take no part in a dread; 
this may be due to its less colonial nesting habit. 

The apparently co-ordinated mass flights of terns are never directed 
to the expulsion of a common enemy, such as man or another creature 
trespassing in the territory of a ternery. But like the skuas and some of 
the larger gulls, the individual tern will attack any trespasser passing 
its nest. The ensuing fight with another bird may embroil several 
other neighbours. Also like the gull, but with much greater accuracy, 
the individual tern will defaecate upon the visitor, fouling his clothes 
or person; and some species are extremely bold, freely striking the 
intruder on the head (arctic and common terns). The noddy attacks 
human beings quite savagely; this and other species will knock a 



264 



SEA-BIRDS 



joy ^ 




Fig. 47 
Breeding distribution of the 
black tern, Chlidonias nigra. 
Black lines embrace prob- 
able extent of breeding- 
range; black dots represent 
some known breeding places 



hat off, and draw blood with the sharp pointed bill. Sometimes 
two or more join forces, hurling themselves repeatedly at an enemy, 
screaming and striking. Yet this behaviour is not always successful: 
skunks ignore it and kill terns freely. Short-eared owls will pounce 
on and carry off both adult and young terns. But dogs, rabbits, rats, 
sheep, lambs and other birds are effectively driven away. 

Gulls especially seem to draw the anger of terns and are successfully 
driven away from tern eggs and chicks. The common tern has been 
known to kill young ring-billed gulls, driving them to the water and 
stabbing their heads — the old gulls offering no resistance. Herons, 
which if permitted would no doubt do a great deal of damage by 
devouring chicks, are violently attacked and driven away. 



TERNS AND SKIMMERS 




265 



Fig. 48 

Past breeding places of the 

black tern, Chlidonias nigra, 

in Britain 



IE LONG. 



I Solway Flow, ? 1855. 2 Streams near Driffield, 'not for some years' by 1844. 
3 Crowland Wash, 1832. 4 Whittlesey Mere, 1843, ? 1844. 5 Poppylotts, Southery, 
early XIX century. 6 Fentwell, 1853 (flood). 7 Brandon, ? early XIX C. 8 Sutton 
1858. 9 Horsey-Winterton, 1816, 1818, extinct before 1838. 10 Upton, 1818. 

II Oulton Broad, ? 1875. 12 Mildenhall, Pearly XIX C. 13 Bottisham, 1824. 
14 Ot Moor, ? c. 1857. 15 Romney Marsh c. 1787, 1824, c. 1884. 16 Pett Level, 

1 94 1, 1942, failed 1943 



The relations between the fledged chick and its parents seem not 
to have been studied adequately. According to Palmer (1941) the 
chick remains attached to its parents and is fed by them at the start 
of the southward migration, which begins in August. The Marples 
remark that the "young ones which have been hatched early, set off 
with their parents for their winter quarters as soon as they can fly 
properly." According to the Marples the first autumn migration begins 
at the end of June in the British Isles, only a month after late-arriving 
adults ( birds born in the previous year ? ) appear in the colony — 
birds which may or may not have time to breed. In a successful sum- 
mer terneries may be quite deserted by the beginning of August in 
temperate latitudes. In the far north arctic terns do not arrive until 
mid-June, and they leave before the end of August. 

Ringing has shown that some young terns will return to nests in 



266 SEA-BIRDS 

the colonies where they were bom, but others move to more distant 
terneries. Palmer (1941b) states that the common tern takes usually 
three years to reach breeding age. We have mentioned the complete 
removal of some terneries to a new site in an apparently whimsical 
fashion. It has been suggested that persecution by man is less important 
as a factor influencing the change of breeding ground than shortage 
of food supply, and that colonies suddenly reappear and breed in 
abandoned, or take up, sites, when the fishing happens to be good 
in that district. But these statements are very difficult to substantiate. 

The annual moult takes place from July to December; it is of 
necessity gradual, since it is during the moult that terns perform their 
great migrations to the south. They do not, however, necessarily 
move south immediately after the breeding season. Ringing has proved 
that many individuals wander in the opposite direction. Juvenile 
Sandwich terns may fly for distances up to 350 miles northwards from 
their breeding quarters. This is the time of year when terns are wide- 
spread along the North Atlantic seaboard, appearing on shores far 
from breeding grounds, especially where there is an abundance of 
small fish. The arctic tern ranges the whole width of the North Atlantic 
during July, August and September (Rankin & Duffey, 1948). Its 
wanderings (see Fig. 23, p. 142) are astounding: it makes a round trip 
during the year of some 22,000 miles, or, during actual migration, about 
150 miles per day in a straight line — if we make the generous allowance 
of 20 weeks for the period of both migrations. The main northward 
migration is believed to be speedy and relatively brief, consistent with 
the mass arrivals at breeding grounds. The autumn migration, as we 
have indicated, is leisurely and drawn out. 

Early in the spring there is a second complete moult, when the 
adult tern acquires its full breeding plumage. In their first summer 
(a year old) young sea-terns generally lack the full black hood, but 
may breed in this plumage (skins of breeding birds in this plumage 
are in the British Museum), although probably the majority do 
not, but instead wander northwards more slowly than mature birds, 
and, as the Marples point out, arrive at the breeding ground too late 
to do more than familiarise themselves with the site. Lockley (1942, 
p. 214) found non-breeding common terns roosting on the Desertas, 
Madeira, in mid-July; this would be near the southern limit of their 
breeding range in the Atlantic. The marsh-terns migrate within a 
shorter range of latitude, seldom flying farther south than the tropics 
in winter. 



CHAPTER 13 

THE AUKS 



IN THE COURSE of cvolution many sea-birds, and groups of sea-birds, 
have independently become adapted to under-water pursuit. Three 
groups in particular, the penguins, diving-petrels and auks use their 
wings as the primary organs of propulsion under the surface. Different 
as the auks are in appearance from the gulls and waders, the structure 
of their palate and other anatomical considerations show conclusively 
that they are closely related to them: this is supported by palaeonto- 
logical evidence, though the order Laro-Limicolae split into ancestors of 
the three present families Charadriidae (waders), Laridae (skuas, gulls, 
terns and skimmers) and Alcidae (auks) as early as the Eocene. The auk 
that most closely parallels the penguins, the quite flightless razorbill 
Alca impejinis, the great auk, became extinct on 4 June 1844 (see p. 65). 
Twenty-one species of the family Alcidae survive ; some people assign 
them to thirteen genera, though systematists more interested in points 
of similarity than points of difference, more interested in fundamental 
rather than easily-modifiable characters, could probably cut them 
down to a more realistic nine or ten; and might reasonably also 
take the number of species down to eighteen or nineteen by reducing 
some to sub-species. 

There seems to be no doubt that the main evolution and adaptive 
radiation of the auks has taken place in or not far from the Bering 
Sea. Sixteen of the twenty-one surviving species breed in the north- 
ern part of the North Pacific, twelve in the Arctic Ocean, and only 
five in the northern part of the North Atlantic. These five are Alca 
torda, the razorbill; Uria lomvia^ Briinnich's guillemot; Uria aalge, the 
guillemot; Cepphus grylle, the tystie or black guillemot; and Fratercula 
arctica, the puffin. All these breed also in the Arctic Ocean, and two of 
them (the guillemots) also in the North Pacific; moreover the tystie and 
puffin have replacement-species (which in the case ol the tystie is con- 
sidered here to be of only subspecies level) in the North Pacific. The razor- 



268 SEA-BIRDS 

bill alone has no Pacific representative; and its extinct relative the 
great auk (which though placed now in Pinguinus should be restored 
to Alca) had only a North Atlantic distribution. Besides the five 
mentioned, the little auk, Plautus alle, breeds only on the Atlantic 
side of the arctic, and operates in winter only firom the edge of the 
Atlantic pack-ice to a varying distance in the open Atlantic Ocean 
and North Sea. It fills an ecological niche in the North Atlantic, 
similar to that occupied by the five auklets* in the North Pacific. 

So we have six living auks to consider in our study of North Atlantic 
birds. The somewhat sombre history of the extinct one has already 
been enlarged upon in our discussion (p. 64) of the impact of man 
upon the sea-birds. The great auk was a large bird of penguin-like 
habits and appearance, standing about two feet high. Newton (1861) 
gives the following notes from descriptions by Icelanders who had seen 
the great auk alive: "They swam with their heads much lifted up, but 
their necks drawn in; they never tried to flap along the water, but 
dived as soon as alarmed. On the rocks they sat more upright than 
either the guillemots or razorbills, and their station was further re- 
moved from the sea. They were easily frightened by noise, but not 
by what they saw. . . . They have never been known to defend their 
eggs, but would bite fiercely if they had the chance when caught. 
They walk or run with httle short steps, and go straight like a man." 
We would also quote Martin (1698) again: "It comes without regard 
to any wind, appears the first of May, and goes away about the middle 
of June" at St. Kilda. As already pointed out (p. 70), this may have 
been quite accurate, since it is just possible that the great auk could 
have completed the terrestrial period in seven weeks, allowing about 
40 days for incubation, and nine days for the chick on the land (com- 
pare these periods in the razorbill, described below). 

The great auk bred in colonies. It was easily driven into a cul-de- 
sac. As a result slaughter in a wholesale manner took place at its 
remote breeding grounds, fishermen and seal-hunters seeking the bird 
and salting numbers of them down for consumption at sea later. 
The great auk laid one Q.gg, coloured and marked like that of the razor- 
bill, and brooded it between the legs, having only one brood-spot 
(Faber, 1826). Little else is known about its breeding habits, which 

*Ptychoramphus aleuticus, Cassin's auklet; Aethia psittacula, the paroquet a. ; A. 
cristatella, the crested a. ; A. pusilla, the least a.; A. pygmaea, the whiskered a. We 
follow R. W. Storer (1945) in regarding the 'rhinoceros auklet,' Cerorhinca monocerata, 
as a puffin. 







< 



o 






T5 



1^ 




"V^ 









-4«ii 



*" ^"S 






«l» 



H 



Roger T. Peterson 

Plate XXXVIa. Black Skimmer and chick, Oak Island Beach, Long Island, U.S.A. 



b. Gull-billed Tern family 



F. P. J. Kooymam 




THE AUKS 269 

probably corresponded closely with that of the other member of the 
genus Alca, the razorbill. 

Auks fly in a straight line with a somewhat bee-like whirring of the 
wings. The rapid beating of the wings gives the impression of speed and 
power, but this is illusory, and auks may be seen to make little progress 
against a strong wind, and are easily outdistanced by the gulls, whose 
wings beat in a leisurely fashion. The short narrow wings of the auks 
make the take-off from the level surface of the land or the sea difficult 
in calm weather. Their whole structure is better adapted for flying 
under the water; the wings, being then half-open with the primaries 
more or less closed, form in this position powerful paddles or oars, 
and the bird moves rapidly through the water. The feet are used in 
steering movements, turning both in air and water; but not as a means 
of propulsion under water, except when the bird is moving slowly 
or "marking time" in its search for fish, or when first diving down from, 
or coming up to, the surface. 

The lives of many sea-birds are spent in three distinct ecological 
zones or habitats, which are shared harmoniously or competitively 
with other species: the feeding and wintering area of the open sea, 
the collecting or loitering ground (Johnson, 1941) near the breeding 
site, and the breeding or nesting site itself. The auks, feeding 
much on the same foods, share the first of these areas between themselves 
without coming into serious conflict. There are diflerences in feeding 
habits and in food taken, as we shall presently show; all auks are divers 
and live by capturing their food principally within twenty fathoms of 
the surface of the sea. Razorbills, guillemots, little auks and puffins 
frequently gather in huge dense rafts on the sea below the breeding 
grounds; this is the second functional area, the loitering or assembly 
place. The third area, the breeding ground, however, is split up between 
the species, each occupying its special part, or ecological niche, of 
the available nesting sites. Competition for territory here is principally 
between individuals of the same species, less often between individuals 
of related species. 

The guillemots are the most social of the auks, forming densely packed 
"loomeries" of thousands of individuals standing or squatting less than 
a body's length apart; and, in spite of the vocal uproar and gesticu- 
latory movements, territorial pugnacity (seen in other social species, 
such as the gannet and the gull) seems to be submerged in the general 
necessity for mutal tolerance. If guillemots were really pugnacious, 
each pair demanding the same amount of nesting room (one body's 



270 



SEA-BIRDS 



^d. 


^i^-|lH?J5N 






i/^w 


w 




isiandicarj^^ 


•^ not now 




r-5 


r-vS^^ 



Fig. 49 
Breeding distribution of the razorbill, 
Alca torda. Black lines embrace probable 
extent of breeding-range; black dots 
represent some breeding-places; there 
are many others in Britain and Eire 



length, plus striking range ot 
the bill) as the gannet, they 
would not be able to breed 
successfully in their familiar 
dense colonies on narrow 
ledges. They manage to do so 
often tolerating less than one 
body's width between sitting 
birds, although unmated 
birds do not usually stand to- 
gether with their wings or 
"shoulders" actually touch- 
ing. The first massing of 
the guillemots on certain 
favourite cliffs and the 
tops of isolated stacks takes 
place in England, Wales and Ireland in December, and, in 
Scotland and farther north, in January. In South Wales there is 
a belief among fishermen that the "eligugs" (guillemots) return "in 
time for Christmas." These early visits are few and irregular; they 
take place at dawn and last only for three or four hours. They may take 
place on two or three succeeding days, and almost always during 
fairly calm weather. In order to be successful the individual must 
early locate, claim and retain breeding territory — where a species 
is so congested in dense colonies that not a square foot of the coveted 
ground is unoccupied at the height of the breeding season. Neverthe- 
less at many breeding sites, certain ledges (which may have been used 
by breeding guillemots in other years) which appear perfectly suited 
to the successful breeding of guillemots, may not be used at all, the 
colony continuing to crowd just as densely upon the occupied ledges; 
in this species slum conditions are a preferred habit rather than an 
absolute necessity. But crowded conditions may provide social stimu- 
lation which leads to more successful breeding (Darling, 1938). We 
have described how guillemots find this stimulation as well in contact 
with other sea-birds (p. 173): as when razorbills share the same ledges 
and where guillemots nest in the narrow "neutral" zones between 
the pedestal-nests of gannets (e.g. Grassholm, Alderney). 

The razorbill, less colonial than the guillemot, returns later in 
spring. In large colonies it may come to land at the end of January 
in its southernmost breeding grounds, but main arrivals occur towards 



THE AUKS 271 

the end of February, and the paired birds do not settle finally upon 
the rocks until the beginning of April, or even, in the far north, a 
month later. Razorbills, too, migrate farther south than guillemots, 
which may be seen throughout the winter in home waters. 

Puffins winter in deeper water farther at sea and are later in return- 
ing to the breeding ground, being seldom seen within sight of land, 
except casually, until the early part of March. At large colonies on 
the southern coasts of England, Wales and Ireland puffins settle on 
the water under their breeding cliffs with great regularity during the 
last week of March (in the north of Scotland and the Faeroes in mid- 
April) . Yet although they are the last of the three common auks of 
Britain to arrive at their breeding grounds, puffins are the first of the 
auks to lay, and eggs may be found in the last fortnight of April, 
long before the main colony has settled permanently on land. This 
is some four weeks before egg-laying in the guillemot and the razorbill ; 
and as we shall see in describing its breeding biology this early laying 
is probably connected with the much longer incubation and fledging 
periods of the puffin. Little auks return to the arctic land before it is 
free of winter and perform their courtship on ice in May and early 
June. 

The three species of guillemots (the common, Briinnich's and 
the black) have been placed by many systematists in one genus; but 
the black guillemot, by its choice of habitat, more closely resembles the 
razorbill and the little auk; and it differs much from the other guille- 
mots and the razorbills in having two eggs, a more markedly different 
winter plumage, and a different pelvic design. It lays its eggs (normally 
two) in a crevice under stones or boulders; in this well-protected site 
the young are comparatively safe, and do not leave the nest until they 
are fully grown and able to look after themselves. In this they resemble, 
not the razorbill, but the puffin. The majority of razorbills lay their 
eggs in more exposed situations where they are more subject to the 
depredations of gulls; only a minority nesting under stones or out 
of sight in holes. 

We thus have an interesting ecological division of the rocky cliffs: 
the common and Briinnich's guillemots occupying the most exposed 
platforms and shelves, and the cliff-top, and rarely laying the egg under 
the protection of the talus; the razorbill, sometimes laying its egg 
upon ledges exposed to sun and wind, but usually nesting in more 
sheltered situations in the shadows of fissures and under boulders, and 
even well inside rabbit or puffin holes in the cliff; the black guillemot 



272 SEA-BIRDS 

and the little auk with their eggs entirely shielded by the rock cover; 
and the puffin nesting in the safety and darkness of its burrow. It is 
even more interesting to find that of these living auks the common 
and the Briinnich's guillemots (Hke the extinct great auk) have a single 
large brood-spot between the thighs. The razorbill, the little auk 
and the puffin normally lay only one egg, yet, like the black guillemot 
(which lays two eggs), they carry two brood-spots. On the razorbill 
and the puffin the brood-spots are remarkably small and narrow, 
situated on each side of the body close to the wing and thigh. They 
are so reduced that only a comparatively small portion of the egg can 
be accommodated against the bare skin, the rest being covered by one 
wing which, being insulated by feathers, cannot, of course, provide 
the same amount of heat as the brood-spot. 

The double brood-spot may be a relic of an earlier period in the 
evolution of these birds when two eggs were normally incubated. 
It might be argued that incubation of two large eggs within the narrow 
confines of an underground burrow, at least in the case of the puffin, 
would be inconvenient and therefore disadvantageous to the species. 
However, in the little auk this cannot apply; there is normally plenty 
of room in the little cavern under the rocks. The Ggg of the puffin is 
white, like that of most hole-nesters, but when held up to the light it 
exhibits a washed-out lilac or brown pattern, suggesting a protective 
colouring at an earlier stage of evolution, when presumably the species 
was an open-site breeder. It may well be that the puffin has become a 
hole-nester from an open-site breeder and that the razorbill is in a 
preliminary stage of evolution from the period when it brooded two 
protectively-coloured eggs in the open. Two eggs are sometimes, 
though rarely, brooded by both razorbill and puffin, but there is no 
record of their successful hatching. Further conjecture on this sub- 
ject, however, does not seem called for in the present state of our 
knowledge. It must suffice here to point out that the razorbill incu- 
bates its egg under "one falling wing" not because the egg is so large 
(as has been suggested by one writer — an invalid reason: the guillemot 
is scarcely as large as the razorbill but it has a larger egg which it 
incubates between the thighs) but because of the situation of its brood- 
spots. 

We have seen that territory-finding and claiming in the auks 
begins early in some species, later in others. The sexual bond brings 
the auk pair to the familiar nesting site in the spring. It has been stated 
that auks, on their arrival on the water below the cliffs, are already 




o 

S 
u 

'3 
O 



o 



2 



03 






O 

N 

a 



i 

■Si 

"a 

a. 



'':,<^' 







Plate XXXVIIIa. Black Guillemot, July (Nordi Rona) {Robert Atkinson) 



b. Little Auks, winter (Channel Islands) {R. M. Lockhy) 




THE AUKS 273 

paired, but there is little clear evidence of this. We do not know how 
early or where mate-recognition takes place, or how far the paired 
birds keep together after the breeding-season. It is only when a pair 
is completely isolated from the main colony, especially in the case of 
the more solitary black guillemot, that we can be sure that the mated 
pair associate regularly on the water near their home. There is strong 
circumstantial evidence that, in the larger colonies of common and 
black guillemots, razorbills and puffins, there is intermingling and some 
promiscuity between individuals on the water under the breeding- 
cliffs. Winn (1950) found the male black guillemot directed his atten- 
tion to several females at first, but later concentrated on his mate. 
Similar behaviour may sometimes be seen in the puffin: the male 
has been seen guarding a female (presumed — from the smaller size 
of the head) from the attentions of other males, by swimming between 
her and other males, which he attacked "when the intruder was two 
or three body-lengths away from the female, and it seemed that as far 
as the male was concerned this area was part of the female and could 
be violated as if the intruder was actually touching her. The female 
was never seen to initiate attacks" (Conder, 1949). Male puffins have 
been watched by us pursuing one female after another, and the same 
male has been seen to "guard" a female for a short time before swimming 
after another female which finally allowed coition; it is not proved 
therefore that each pair seen together on the water in a large raft are 
necessarily mated and sharing the same burrow on land. However there 
is also definite mate-recognition on the water (Lockley, 1934), since 
occasionally a pair will rise in the air together out of the raft and fly 
to a single burrow in the cliffs. At the terrestrial nesting site mated 
puffins are faithful to each other, as we shall prove later in this chapter. 
We may compare this pre-egg-laying promiscuity with that of the 
cormorant, where it is the female which seeks occasional extra-marital 
coition; and with that of the Buller's mollymawk, where males adult- 
erously attack and forcibly copulate with the females of mated 
pairs. 

Although we have not been able to prove that mature auks, on 
arrival off the coast of the breeding cliffs, are already paired, it must 
be the case that a large proportion of the experienced breeders return 
to the same crevice or burrow or niche in the rocks where they nested 
a year ago, and there discover their mate, also of the previous year. 
A mated pair oi auks can be watched flying close together, sometimes 
as far as the eye can follow them, from the moment they leave the edge 

T 



274 



SEA-BIRDS 




? overlap between 
e.g. snowi and C. airbo 
„kaiurka ^^i J 



Fig. 50 
Breeding distribution of the tystie or black guillemot, Cepphus grylle and its allies 
and races. Apart from the black-winged guillemot, Cepphus carbo, the Pacific races 
are considered to belong to C. grylle, though many American workers separate them 
as the pigeon-guillemot, C. columba. Black lines embrace probable extent of 
breeding range; black dots represent some known breeding-places. 



of the cliffs ; but often the pair separate soon after leaving the cliffs, 
and one may alight on the sea while the other flies on. 

When assembled in early spring on the water below the breeding 
rocks and cliffs auks carry out mutual display, in the form of "water- 
dances." Razorbills and guillemot pairs will swim around each other, 
at the same time opening the mouth to display the coloured interior 
and uttering guttural cries. The head is thrown back and upwards 
with a jerky action, repeatedly. The other bird may show little interest 
in this display, but usually keeps swimming so that it is face to face 
with its partner: or both birds may display mutually, and a third or 
fourth may join to form a circle of displaying birds. These water- 
dances differ somewhat in each species. A party of razorbills or 
of black guillemots will often form a line, sometimes two parallel 
lines, swimming in this formation "line ahead" for short distances. 



THE AUKS 275 

making almost a formal pattern on the water. But these lines last for 
a matter of seconds only and as excitement increases there is a con- 
vergence, which is broken up by the sudden submerging of the whole 
party, individuals frequently pursuing each other under water in an 
erratic and excited manner. They may afterwards disperse or come 
together in a fairly dense unit, and, after a. pause of variable duration, 
resume the "line ahead" formation. Armstrong (1940) describes fully 
these water-dances of the black guillemot. Each bird appears very 
excited, frequently adopting an ecstatic posture with the tail cocked 
at right angles, the head from time to time thrown up parallel with 
the tail, the beak partly open to display the interior colouring of the 
mouth (chrome-yellow in the razorbill, vermilion in the black guille- 
mot, flesh-yellow in the puffin and common guillemot). The puffin 
has no formal water-dance; but there is pursuit of the female by the 
male on the water, where coition takes place. In other auks mating 
takes place on the land; and there is more excitement on the crowded 
ledges of the guillemot loomery than on the water. Although common 
guillemots tend to join in the razorbill dances, their excitement on the 
water seems to find expression in mass dives or sudden skating over 
the surface, rather than in a stereotyped ceremony. Mass dives also 
occur when there is a convergence (of perhaps more than one species), 
with danger of collision. Such a concentration may be assisted by tide 
and wave action, forcing individuals so close that the boundaries of 
"individual distance" are violated; the observer notes the increasing 
alarm, expressed in the raising of heads and the rapid turning of the 
body this way and that, which ends in the simultaneous dive, and the 
escape and dispersal under water, relieving the pressure at the surface. 
The huge painted bill of the puffin is used as an instrument of 
communication much more than are the bills of the other auks; 
for the puffin, by comparison with the noisy guillemots and the 
razorbill, is almost silent. The puffin's bill is thrust forward towards 
a neighbour, a mate, or a bird of the opposite sex at first in the threat 
position resembling the "forward display" of a fighting cock or a dog 
about to attack another. In this position (the bill slightly tilted ground- 
wards) the brilliant colours, the eye-patches and the rictal rosette 
are most conspicuous. If the bird displayed at is male and stands his 
ground (or position in the water) he may be attacked and a short fight 
will ensue ; if she is female, she may ignore the display, or move away. 
There is a tossing movement of the head, which is mutual, and is 
evidently an appeasing ceremony (possibly derived from actions when 



276 SEA-BIRDS 

fishing under water), since it momentarily hides the conspicuous 
bill from a partner. The well-known bill-rubbing ceremony of the 
puffin is like the bill clashing of the gannet; it may have its origin 
in threat display. It is initiated as a rule by the male: approaching his 
partner in the threat attitude, he begins to quiver his head to and fro, 
thus signalising that his intention is not hostile (the bill remains stiff in 
hostile display). Elements of threat seem to remain in the violent 
pushing movements of the male as he shakes and presses his bill against 
one side of the female's, and she is sometimes pushed off her balance 
as a result. In a large assembly on land a bill-rubbing pair, or a 
pair fighting, at once attract neighbours, who crowd round, and, 
by joining in the ceremony, break it down; we have seen three puffins 
bill-rubbing together, with more trying to join in, or three or four 
in a fight — but always the action was broken off quickly, and the 
birds separated and moved their normal distance apart (Lockley,i953). 
Puffins are intensely curious of all movements near them in the 
puffinry, and will toy with the snare or hook at the end of the 
fowler's rod as it slides over the ground towards them. 

Bill-rubbing or pushing takes a milder form in the little auk 
(Foster et al., 1951) and the razorbill (Paludan, 1947). Courting 
guillemots are so short of manoeuvring space on the crowded ledges 
that the pair may stand shoulder to shoulder in courtship, caressing 
each other in this position, bowing and groaning with heads sideways 
(Johnson, 1941). The holding of a fish in the bill of a guillemot early 
in the season Johnson considers to be part of the courtship ceremonial, 
and he records its retention for long periods — up to four hours. We 
may compare this with the fish flights of the terns (p. 255). 

Armstrong (1940) considers that the brilliant red colour of the 
legs of the black guillemot may be functionally useful in the under- 
water chases which are "nuptial, connubial and recreational." As 
the tysties flutter along like large exotic water-butterflies just below 
the surface, they may be guided by the bright webs of the leaders. 
Certainly in this rotund species the feet are used as paddles more 
freely under the water than in other auks. But puffins, with vermilion- 
coloured legs and webs, are less given to this form of social behaviour 
than are the black-footed razorbills. 

Black guillemots face each other, bowing and whistling until 
the female suddenly squats flat on the rock with her tail erect; the 
male mounts, paddling with the feet to maintain position while copulat- 
ing. Razorbills and common guillemots mate, noisily groaning, at the 




^ 




Rvbcii Atkinson 

Plate 7. Razorbills sunning on the cliffs of Skokholm, Pembrokeshire 



THE AUKS 277 

egg-laying site, and, like puffins copulating on the water, beat their 
wings to steady themselves as they rest far back on the back of the 
female. Little auks have a whining chatter, puffins a somewhat 
rare sighing double note, an inspiratory gasp, followed by an expiratory 
yawning note. 

The puffin is the only Atlantic auk which is active in preparing a 
home. As it breeds under the ground it must and does dig efficiently, 
using its bill as a pickaxe and its webbed feet as shovels to fling the 
earth backwards — it will excavate a burrow even in soft sandstone, 
as at Skokholm. The other auks adopt ready-made sites. A razorbill 
may pluck and play with a piece of grass, but there is no attempt to 
use it for lining the bare spot in which the egg is laid. Some black 
guillemots will carry feathers, bones, shells, stalks and debris to the 
nesting crevice. Plucking, picking up, and toying with grass, seaweed, 
and feathers is a displacement activity. The puffin may transport 
these materials into its burrow and drop them in the nest at the far 
end. It may just as often drop them outside the burrow or in the pas- 
sage, or even drop them before reaching the entrance. We have 
watched the puffin pluck furiously at a tuft of grass or herbage until 
it has accumulated an immense beak load, larger than its own head. 
This it has held in its bill for perhaps five or ten minutes, as if pleased 
and proud of its efforts. A puffin so burdened with material is an object 
of special curiosity to other puffins. They will approach, with their 
mincing steps, and even presume to snatch the material from the owner, 
who shows anxiety to avoid being robbed, and backs or runs away 
with it. A large feather is a much coveted object; its possession may 
be disputed in a tug-of-war, and it may pass from one to another of 
the assembled puffins before it is blown away or carried into a burrow. 
But in spite of this activity and play with nesting material little is 
finally deposited in the nest at the end of the burrow. Indeed the Ggg 
is often found with no nest lining around it. 

The ringing of puffins by Lockley (1953) has shown that the male 
remains attached to the same female during the season (at least while 
on land), and takes a minor part in the incubation of the egg. As 
long as he is on land the male shares in all the activities, including that 
of spring-cleaning the burrow in April (or driving a new shaft where 
the old burrow has fallen in or become damaged during the winter) . 
Puffins may excavate and clean out passages throughout the season; 
the tremendous burrowing capacity of a large colony may undermine 
the earthy slope of a whole cliff side, causing it to slide into the sea 



278 



SEA-BIRDS 




Fig. 51 
Breeding distribution of the puffin, Fratercula 
arctica, and its Pacific counterpart the horned 
puffin, F. corniculata. Black Hnes embrace 
probable extent of breeding range ; black dots 
represent some known breeding-places 



(North Rona, Darling, 
1947), or render the site 
so porous and flimsy 
as to be untenable after 
a few decades, as at 
Grassholm (Lockley, 
1938). The compara- 
tive safety of the burrow 
from predators enables 
the puffin to leave the 
&gg or chick for long 
periods with impunity. 
It has been observed 
that razorbills, nesting in 
well-concealed crevices, 
will also leave the tgg 
or chick alone, but for 
a shorter period. The 
habit is of further signifi- 
cance if we connect it 
with the implications 
of the double brood- 
spot in these two birds: 



if the puffin and the 
razorbill formerly laid two eggs (as the double brood-spot suggests) 
the present delay in beginning incubation of the single ^gg in these 
species is explicable as the survival of a once useful habit (of com- 
mencing incubation when the clutch was complete) which no longer 
serves its original biological function. In this connection it is interest- 
ing to note that the black guillemot (with two brood-spots, near the 
centre of the breast) itself may be following the same evolutionary 
trend towards one ^gg. Frequently only one is laid, occasionally 
three, but two is the normal clutch; but though two may be hatched 
as a rule only one chick is reared (Armstrong, 1940). MortaUty is 
heavy: Winn found 73.8 per cent, loss of eggs and young in forty-six 
nests. The brooding bird seems deliberately to incubate one ^gg only — 
Winn found that "unwanted" eggs were pushed out of some nests, 
even when he replaced them. 

The common and Briinnich's guillemots, with the Q:gg fully exposed 
to attack from the air if it is uncovered, never voluntary leave the Qgg 



THE AUKS 279 

(or the chick) alone; one or other of the pair (or of other adults of the 
colony?) remains with it. Thus it is protected from attack by gulls, 
skuas, etc. ; but at the same time it is not safe from the risk of being 
stolen or pirated by neighbouring adult guillemots. 

Puffins are essentially sociable birds. During the period when 
one or other of the pair is incubating it is out of sight of the main 
colony and is thus denied the stimulating visible presence of its fellows 
which the guillemot enjoys. As if to make up for this, at certain periods 
of the day, and especially on summer evenings, both male and female 
puffins abandon the egg for two or three hours at a stretch, and sit 
about and parade on the cliffs in a recreational assembly. The egg 
does not appear to suffer as a result of this temporary cooling. For 
the rest of the twenty-four hours it is probably much more steadily 
incubated than those in the restless colonies of the razorbill and 
guillemot. Observations on large colonies of these two species show 
that there is a constant interference in incubation by the shufflings 
and movements of the massed birds, the egg being frequently uncovered 
in the process. 

The scene in the common guillemot colony is fascinating to watch. 
Gatke, in his book on Heligoland, describes the guillemots aptly as 
making an "endless obeisance" and the birds all talking volubly 
about nothing in particular. The larger colonies seem to bubble 
over with a non-stop excitement as a result of the perpetual bobbing 
and bowing and shaking of each head and of the mild squabbles 
of close neighbours and of the disturbances caused by each new arrival, 
who is greeted so boisterously. When alighting in a colony the guillemot 
announces its arrival with loud squawks, as if to warn those on the 
ledges to make room for it, and it is usually received with apparently 
aggressive cries. On the ledges progress is by means of a shufflng 
walk with the whole tarsus pressed on the ground at each pause, 
the body being held perpendicular. The razorbill walks in the same 
way. Sometimes, when flying down to the sea, the auk moves its 
wings at about half the usual speed, giving the appearance of slow 
motion or, as it has been called, "butterfly" flight; in the puffin this 
change in the usual mode of flight takes the form of a curious gliding 
with the wings held high and the wing-tips rapidly fluttering in a 
kind of "moth" flight. 

The eggs of the guillemot, varying so much in colour, are large and 
pyriform; a design which minimises rolling but does not always 
save the egg from tumbling over the narrow ledge. Johnson (1941) 



6o' 



59- 



13" H* 11' 10" 9° 8° 7" 

I I I i 1 1 ' — - — — 1— 



lOOKM 12 - 



?• f y 2° f 



0° 1° 2' 



^r 



miles: 



KA\: 



11 



100 




LAT 



. I . , . . ■ . ■ I 



:7 



' I ' o 



W LONG 9' 6' 7" 



i'E LONG 



Fig. 52 

Some present (black dots) and past (open dots) breeding places of the puffin 

Fratercula arctica, in the British Isles. There are unmarked breeding places on 

Eigg, N.E. Islay and Bishop Rock off Ramsey. No puffins were breeding at 

the station at the mouth of Loch Broom in 1952. 



THE AUKS 281 

suggests that the chief functional value of their peculiar shape lies in 
a larger surface being in contact with the bird's belly during incuba- 
tion. The great auk, with one brood spot, had a pyriform egg, too. 
Puffins and little auks, nesting in safer situations, have somewhat round- 
er (yet still pyriform) eggs (and two brood-spots). Both sexes incubate. 
There is evidence that in guillemot colonies of above a dozen pairs, 
eggs may sometimes be pirated and adopted by neighbours (Lockley, 
1934). Johnson states that the common guillemot (or murre, as it is 
called in America, where his study was made) recognises its egg and 
moves it back into the old position if it rolls away or is experimentally 
transposed by the observer; in three instances the adults whose eggs 
had been moved "hovered" first on the vacant egg-site, then seeing 
the egg in a new postion, went to it and by degrees shuffled it between 
the breast and legs until the original site was regained. But one 
guillemot which had lost her egg was seen by Johnson to "steal" 
another from the mire accumulated in a depression on the ledge and 
"moved it about twelve feet to the location where last evening it 
covered (the lost egg)'', further evidence of the determined pirating 
of eggs by bereaved adults. 

Some eggs become so fouled with slime, which dries to a hard coat, 
that the original beautiful colour is lost, and many must be only 
recognisable by their position on the ledge. 

Gulls patrol cliffs where guillemots breed, and become bold in 
the search for eggs and small chicks. We have watched a herring- 
gull alight on a ledge and try to force a sitting guillemot from its egg. 
After visiting a guillemot colony, many observers have watched gulls 
seize the eggs before the slower-flying guillemots, frightened away by 
the human intruders, returned. Small guillemot colonies may lose 
all their eggs as a result of a single visit by a human being. More 
rarely the sudden swoop of a gull will cause a panic in which the 
frightened guillemots leap from the ledges before disengaging their 
feet and breast from the egg, which is then accidentally carried out 
and dropped in mid-air. The guillemot will lay at least once again 
if the first egg is lost when fresh. Winn (1950) found that black guille- 
mots replaced fresh eggs, which had been destroyed, in 15 days; 
but there was no re-laying after June. 

Very little reliable data on the incubation and fledging-periods 
of auks was published until the work of Lockley (1934c) on the puffin, 
and Keighley and Lockley (1947, 1948) on the razorbill and common 
guillemot, and Winn on the black guillemot appeared. The results. 



282 SEA-BIRDS 

(averages), given in the table below, show that previous estimates 
[Handbook of British Birds, Vol. 4) were wide of the mark. 





Incubation 


Fledging 


Total 




[days) 


{days) 


{days) 


Common guillemot 


? 


15.8 




Razorbill 


34-3 


15.2 


49-5 


Puffin 


41.7 


49 


90.7 


Black guillemot 


29.4 


39-5 


69 



The disparity between the periods for the puffin and those for the 
common guillemot and razorbill (and probably great auk) can now 
be related to the amount of exposure of the breeding site. In the dark- 
ness and security of the burrow the puffin o^gg and chick is safe and 
can develop slowly and fully. In the little auk and the black guillemot 
colonies there is rather more danger from predatory creatures. (Winn 
found that high tides, and young herring-gulls, caused mortality to 
black guillemot eggs and chicks). The guillemot and razorbill are 
constantly threatened by predatory birds. The most successful guille- 
mots and razorbills therefore must be those which are hatched in 
the shortest time and which spend the briefest period as chicks on the 
ledges. When recording the fledging period of these two auks we noticed 
a significant correlation ; some of the strongest chicks were those which 
flew to the sea within two weeks, and some of the less vigorous chicks 
were those which remained for nearly three weeks on the ledges. 
Where there are large colonies of breeding gulls near those of cliff- 
breeding auks the young auks experience a heavy mortality. In 
British colonies the herring-gulls are the greatest egg-thieves and the 
great black-backed gulls the greatest persecutors of the nestling 
guillemots and razorbills. During our observations of the fledging 
periods of these auks, which were made at Skomer and Skokholm, 
we ringed as many as possible of the chicks. Those which disappeared 
before the fledging day were taken by black-backed gulls, whose 
fresh castings we discovered to be full of the remains of young auks, 
from which we were able to recover some of our rings. 

Nestling auks are fed on fish or plankton, or both. The size of the 
fish varies according to the age of the chick, as well as to its species. 
As the chicks grow, which they do very rapidly in the case of the open- 
site auks, larger fish are brought in. This is particularly true of the 
guillemot and may be associated with the structure of the bill. When 
the chick is about a week old, an adult guillemot will bring home a 



THE AUKS 283 

single fish which is usually slightly longer than the bill and is held 
parallel to the bill, with the tail hanging from its tip. This fish may be 
almost as long as the chick itself; but this formidable meal will be 
swallowed by the chick, always head-first, and digestion begins with 
the head, although the tail of the fish may not visibly disappear from 
the mouth of the nestling for some time. Often after returning from 
the sea with a single large fish the adult will hold it for a long time, as 
during courtship, as it sits semi-upright upon the ledge. Why it should 
do this is not quite clear, but it may be that unless the chick importunes 
sufficiently the feeding reaction in the adult is not released. The adult 
may even fly away from the ledge, still carrying the fish, only to 
return later with it. If all the chicks near the alighting bird have 
been fed recently, there would, of course, be a wastage if the adult 
dropped the unwanted fish at random on the ledge. This does happen, 
though rarely, and if the chick is well grown, vigorous and hungry 
enough, it will pick up the fish then, or later. But usually the adult 
retains the fish until one or other of the chicks of the colony starts 
calling and pecking to be fed. Since both sexes in the adult are alike 
and the chicks themselves cannot be distinguished one from the other 
(unless they vary much in age) , it has not been easy to prove that com- 
munal feeding exists; but hungry chicks will be seen making their 
way past satisfied chicks and brooding adults, to reach an adult 
holding fish. Also chicks have been seen to wander from one adult to 
another, and even to a third, and were brooded by each in turn 
(Lockley, i934d). There seems no doubt that a chick will be adopted 
as easily as an egg may be pirated, even if the adoption of the chick 
is a matter of only a short period during the absence of the legitimate 
parent. There also seems little doubt but that there is voice recognition 
in this species; a chick which feels cold and temporarily has no 
adult to brood it will squeak until its wants are satisfied by the nearest 
willing adult. Yet these squeaks seem to cause more agitation to one 
particular adult than the rest (and this the observer presumes to be 
one of its parents), which may make its way towards the chick, calling, 
or call the chick to its side to be brooded or fed, or both. Promiscuous 
or communal feeding of young birds is not unique to the guillemot; 
it occurs regularly among other sociable species, notably the penguins, 
and has occurred spasmodically with passerine birds. Of mammals 
the female bat is said to feed the first young one which reaches her on 
her return to the crowded communal nursery-roosts (Casteret, 1947). 
Little auks feed their chick on crustaceans and plankton, which they 



284 SEA-BIRDS 

carry in cheek-pouches. Razorbills bring their young somewhat smaller 
fish than the guillemot as a rule, and puffins carry home still smaller 
fry and sand-eels. Razorbills usually hold the fish across the bill, and 
may carry any number firom one to seven or eight in a beak-load. 
Puffins, with their enormous parrot bills, carry many more; we have 
counted 28 small fish dropped in one load from, the bill of a frightened 
individual. This division of fish sizes between the three larger auks, 
varying according to the shape of the bill, is interesting, and suggests 
that the three species have their ecological share — a different food 
spectrum — in the harvest of the sea (see p. 122), just as they have 
their separate territorial niches on land ; competition is thereby reduced 
and the species are able to live as neighbours harmoniously through- 
out the year. 

We may complete the story of the young guillemots and razorbills 
born on the cliffs. The chicks have grown rapidly, but at a fortnight 
old are still only half the size and weight of the adults. Yet during 
these two weeks they have acquired their first coat of feathers at a 
remarkable speed. In the period that it takes the smallest of birds, 
such as the wren, to acquire its first plumage, the comparatively large 
young guillemot or razorbill has grown a thick cushion of feathers 
over the natal down. The flight feathers alone are incomplete; 
the rectrices or tail feathers have in fact not even sprouted. But the 
wings have the appearance of being complete (in relation to the small 
body) because, although the primaries are missing, the primary- 
coverts and greater coverts are well grown. And it is with the aid 
of these, and quite lacking quill feathers, that the young bird flutters 
down to the sea. 

Earlier observers, some of whom obtained the evidence second- 
hand from fishermen and lighthouse-keepers, have asserted that the 
young auks are aided in their flight from the cliff to the sea by one 
or both parents, which were said to support the chick by holding one 
wing (just the thing to upset a flying bird completely); also that the 
parents sometimes pushed a reluctant chick over the edge. It is possible 
that an adult may accidentally jostle a chick which is hesitating on the 
edge of an overcrowded platform, but we do not believe that eviction 
is ever premeditated. Recent observations by Perry (1940), Kay 
(1947) and Keighley & Lockley (1948), have proved that the fledgeling 
takes off on its own account. What happens is at last quite clear: 
the young razorbill or guillemot begins to exercise its wings freely 
as soon as the coverts are sufficiently grown, and the body is well 




o 
^ 



o 



b/D 

-5 






THE AUKS 285 

covered in a soft loose coat of feathers above the thick down; this regu- 
lar wing-exercising begins earlier in precocious individuals. The 
rapidly growing chick becomes restless and may wander some distance 
along a ledge or within the confines of the rocky guillemot plateau. 
It has yet to be discovered whether or not, at this period of about 
two weeks of age, the chick is fed less often ; there is no evidence that 
this is so, but rather the contrary, since there always seems to be an 
abundance of fish being brought in by the adults which, as already 
suggested, are not necessarily, in the case of the guillemot, the parents 
of the chick which they are seen to feed. The young bird has now a 
louder and more insistent call, and appears more and more dissatisfied 
with its confinement on the cliffs. These calls seem to excite less those 
adults remaining on the ledges with them, than those on the sea below. 
It is generally presumed, but not scientifically proven, that it is the 
parents which call to the young bird from the sea. More patient 
observation is needed to clear up this point, which could only be done 
by colour-marking the adults and young. It is reasonable to suppose 
however, that as only one, or at most two, adults seem to answer the 
call of one fledgeling from the cliffs, there is definite voice-recognition 
at this distance. When at last the young chick makes the leap into the 
air and flutters down on a long plane to the water it is claimed by one, 
or by a pair, of adults. These eventually convoy the fledgeling away to 
sea. 

The flight of the young chick from cliff" to sea usually takes place 
at night or early in the morning, but has been observed during other 
hours of the day also. When it occurs in rough weather, with heavy 
seas breaking on the rocks and shallows below the cliffs, the young 
bird may have a difficult passage to get clear. But even when it strikes 
the rocks, it is seldom seriously hurt. It bounces off" and continues to 
scramble and struggle towards the sea. It is sometimes engulfed by 
a heavy surf, but if so it immediately dives, swimming agilely forward, 
squeaking anxiously each time it reaches the surface for a moment, 
while a little farther offshore the adult continues to call encouragingly 
as it swims towards the chick. 

The arrival of the chick upon the water excites the whole group 
of adults in the immediate vicinity. They may make short dives towards 
the young bird as it swims under water. They may surround it when 
it comes to the surface, and they may even make mock attacks, forcing 
it to submerge for a moment. (Contrast this excitement of the adult 
cliff'-breeding auks over the fledgeling with the complete indifference 



286 SEA-BIRDS 

of the adult puffin or petrel towards its chick) . The incident ends in 
the youngster swimming close to the adult which most persistently 
answers its calls, and it is led away to sea. Usually only one adult 
retains possession of the fledgeling in the open sea, but we do not 
know whether this is the male or female, though it is generally presumed 
to be the mother of the chick that takes on the duty. Nor do we know 
the sex of the two adults which sometimes accompany a chick; this 
is a matter for detailed observation by marking. For all we know 
the loving adults may both be female, one the mother of the chick, 
and the other a foster mother who, having lost her egg or chick earlier 
in the season, has adopted the chick and, having fed it often, has 
become attached to it by voice-recognition. 

Convoying of the young bird at sea is recorded for the common 
and Brlinnich's guillemots, the black guillemot and the razorbill. 
The chicks of the black guillemot and the little auk, both born in 
crevices in the rocks, do not leave the nest until they are full grown 
and in complete juvenile plumage. Before leaving there is much 
exercising of the wings. The adults attend the departure from the rocks. 
Winn (1950) found that in one case, at 8.30 p.m. on 12 August 1947, 
a black guillemot parent enticed the 40-day-old chick from the nesting 
crevice by dangling a live rock-eel before it. The chick was drawn to 
the water and the open sea in this way. 

The little auk often nests on cliffs far inland, and the young bird 
has to face a longer flight to the sea. According to W. E. Ekblaw 
(A. C. Bent, 191 9) it is accompanied on its first flight by the adults, 
which do not, however, assist it otherwise. It flies quite well immedi- 
ately, though its progress is naturally slower than that of the adult, 
and occasionally a few fall by the way, and these may become the 
prey of the prowling arctic foxes. 

Very diflerent is the story of the puffin at fledging time. For a 
long time the imaginative accounts of early observers seemed to prove 
that the adults tenaciously cared for the young throughout their 
existence on land. Thus, writing of the Atlantic puffin, C. W. Townsend 
(Bent, 1919) states that "when the young are 4 to 5 weeks old they are 
able to leave their burrows and follow their mothers to the sea." 
Of the horned puffin [Fratercula corniculata) , L. AlcS. Turner writes that 
"the old bird catches the young one by the wing and they flutter at a 
long angle to the water. The old bird endeavours to keep under the 
young one. I have seen them drop their young accidentally and cause 
great consternation of the parent, which could not check her flight 



THE AUKS 287 

immediately, but returned and showed great solicitude by turning 
the young one over and over in the water to see if it was injured. 
During severe storms the young are taken to the lee of some reef or 
islet until the waves become quiet." 

Turner's account is the fabrication of a romantic imagination 
— the truth is much more astonishing. We now know that all 
Fratercula and Lunda species desert their young after a long fledging 
period. The young chick is well supplied with fish during the first 
month of its existence, the adults bringing in several beak-loads 
during the early and the late part of the day. The puffin chick, well 
covered with down when born, and quite active, has been continuously 
brooded for the first week only. We can only conjecture here how the 
young bird is fed in those burrows which are far down in the earth 
and which receive little or no light from the surface. At first it is 
probably fed by touch; but presumably the fish, which are partially 
phosphorescent, are discernible even in darkness, and as the chick 
becomes more nimble it is able to pick up fish from the ground. 
(It has not been proved that puffins have a sense of smell. The olfac- 
tory sense of sea-birds has been little explored, see Fisher, 1952, 
pp. 421-22. and notes on cormorants devouring strong-smelling fish, 
p. 212). 

The newly-hatched puffin is fed first of all on very small fish and 
sand-eels. As it grows older, larger quantities of larger-sized fish are 
brought in, but, as already pointed out, these fish are never so large 
as those fed to guillemot chicks. The ability of the puffin to catch and 
hold up to thirty small fish in its beak at one time has often been 
remarked upon, and it is undoubtedly related to the peculiar structure 
of the bill, and the curious round tongue. The interior of the upper 
mandible has slight serrations which must assist in holding fish. 
There is no doubt that each fish, as it is captured, is immediately 
killed by the sharp pincers of the point of the bill. The popular 
conceptions that the puffin arranges its captures neatly with heads all 
to one side of its mouth, or alternatively, are of course, quite erroneous. 
They are held at random, although always across the bill. 

About the fortieth day the young puffin is entirely deserted by 
its parents, which leave the land altogether and retire to the open 
sea to begin the moult of the body-feathers which takes place in the 
autumn. The deserted chick remains fasting in the burrow for about 
one week, during which the last of the down disappears and the first 
full juvenile plumage is completed, including all wing and tail feathers. 



288 SEA-BIRDS 

At last the young bird proceeds to the sea, alone and always at night, 
when the attacks from the predatory gulls and skuas are least likely. 

In very dry summers, or in those burrows in dry sandy soil, the 
young puffin may be heavily attacked by red mite. Many may at this 
stage be so severely sucked by this ground-breeding parasite that they 
die through loss of blood. On the island of Burhou in the Channel 
Islands in June 1949, we found several hundreds of fledgeling puffins 
dying or dead, in or near their burrows, and covered with blood- 
sucking mites, identified by the British Museum as Dermanyssus gallinae, 
commonly known as the poultry mite. Ticks [Ixodes uriae) attack adult 
puffins in late spring and summer; often the white face of a puffin will 
be quite grey with the bloated bodies of these bloodsuckers, which 
are picked up in the grass and the burrows, and which drop off after 
a few days feeding, as soon as they are engorged. 

At dawn on late July mornings the sea surrounding the islands 
where puffins breed numerously will be dotted with young puffins 
which have made their way to the water during the night. They have 
scrambled over the rocks or fluttered down from high cliffs. The 
strong tides will help to sweep them away to sea. The young bird 
paddles vigorously (for as yet it cannot fly), showing anxiety to get 
out into the open ocean. If attacked by a gull, it escapes by diving. 
The adults take no interest whatsoever in the fledged puffin when they 
encounter it in the water at this time of the year. Nor does the young 
bird betray, by calling or other sign, the slightest interest in the adult, 
except that it will usually swim away from, rather than towards, a 
raft of adults. It is worth noting that in those species described in 
this book which make a night passage to the sea at fledging time, 
there is this complete desertion of the young bird. These two events 
in the breeding biology of these species seemed to be linked with the 
factor of rearing in the darkness of a burrow; the adults, except in a 
few instances where a burrow happens to be short and well-lighted 
from the entrance, have never properly seen their chick, and are 
familiar with it only as a voice and a form in the twilight underground. 
They probably could not recognise it visually at sea in daylight, nor 
is it necessary for them to do so. 

The young puffin, like so many other migratory birds, has to find 
its way alone to the wintering ground of its kind, to the gathering 
place of all juvenile puffins of its own subspecies which have left the 
islands and cliffs in early autumn. But little is known of this movement, 
or of how the juveniles meet with the adults, if they do, on the return 




R. M. Lockl 



Plate XXXIX. Common Guillemots, Skokholm. On the guillemot ledges the adults 
out-number the chicks six to one, due to losses of eggs and young in such an exposed 

situation. 





s: o ^ J3 ^. 



THE AUKS 289 

voyage in the next or some following spring. All we know at present 
is that two young puffins, ringed (by the Marquess of Bute) at St. 
Kilda in August 1939, reached Newfoundland in December of the 
same year; they probably crossed the Atlantic direct (Rankin & 
Duffey, 1948), since puffins have been observed occasionally in mid- 
North Atlantic in December. 

Auks moult completely as soon as they leave the breeding ground, 
and are nearly flightless for a short period in early autumn. Puffins 
shed their facial adornments then, including the cerise eye-ring, 
leathery eye-patches, rictal rosette or "false lips," and part of the lower 
mandible. Guillemots and razorbills are much whiter in their winter 
plumage. The puffin is unique in that the quills are not moulted until 
the spring, when the new nuptial plumage is acquired. 

Probably auks do not return to land in their second summer. 
They may be two or three or more years reaching breeding condition, 
during which they may visit the land as non-breeders, and stake out 
a claim to the future home. The proportion of non-breeders in any 
species of sea-bird laying only one egg each year is probably high, 
although no reliable figures are available. Lockley (1953) found many 
non-breeding puffins at Skomer and Skokholm in June and July, 
none of them less than two years old (the yearling puffin is distinguish- 
able by its small triangular bill and other characteristics). Selous 
commented on the great number of common guillemots on the ledge 
after the last chicks had flown, and thought they could never have 
bred; their numbers were almost equal to the original breeding popu- 
lation. Perry saw the same thing, but misinterpreted it as a return 
to the cliffs of the old guillemots — but these of course were already 
at sea with chicks, and beginning the moult. Winn counted fifty non- 
breeders in July in a colony of fifty breeding pairs of black guillemots, 
and presumably the yearlings were absent; if we add the juveniles 
and fledgelings this gives a high figure, not far removed from parity 
of numbers with the adults. The number of non-breeding fulmars is 
very high (Fisher, 1952); at all but the largest British colonies it 
comprises at least half the birds present at the land-station at the peak 
of seasonal occupation, which is usually in early April. We ought 
not to be surprised at these figures. To counteract the heavy egg^ 
chick and fledgeling mortality in a species laying only one egg expecta- 
tion of life in the mature adult must be high. Long-lived animals do 
not usually begin breeding early in life; about one quarter of or 
one-fifth of their life-span is passed in immaturity. 



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Fig. 53 
Sketch map of the North Atlantic showing isotherms of surface water in July. 
Broken line represents the approximate boundary of sea ice (degrees in Fahrenheit) 




Fig. 54 
Sketch chart of the North Atla ntic showing drift and precipitation 







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APPENDIX 

LIST OF SEA-BIRDS OF THE NORTH ATLANTIC 
AND THEIR DISTRIBUTION 



The boundary between 'arctic' and 'temperate' has been taken, after long 
consideration, as the Arctic Circle, instead of some boundary more real 
geographically but less practical. For the same reason the boundary between 
'temperate' and 'tropical' has been taken as the Tropic of Cancer. Species 
bracketed together tend to be ecological counterparts. 

(i) PRIMARY SEA-BIRDS, BREEDING 



Fulmarus glacialis, fulmar 
Piiffinus diomedea, N. Atlantic 

shearwater 
Puffinus puffinus , Manx shearwater 
f Puffinus assimilis, little shearwater 
< Piiffinus Vherminieri, Audubon's 
(^ shearwater 

C Pterodroma hasitata, capped petrel 
J Pterodroma cahow, cahow . . 
^ Pterodroma mollis, soft-plumaged 
1^ petrel . . 
Bulweria bulwerii, Bulwer's petrel 
Pelagodroma marina, frigate-petrel 
Hydrobates pelagicus, storm-petrel 
f Oceanodroma castro, Madeiran 
J fork- tailed petrel 
I Oceanodroma leucorhoa. Leach's 
(^ petrel 
Phaethon aethereus, red-billed tro- 
pic bird 
Phaethon Upturns, white-tailed 
tropic-bird 



TROP- 


TEMP- 




TEMP- 




TROPI- 


ICAL 


ERATE 




ERATE 


MEDI- 


CAL 


WEST 


W^EST 


ARCTIC 


EAST 


TERR- 


EAST 


ATLAN- 


ATLAN- 




ATLAN- 


ANEAN 


ATLAN- 


TIC 


TIC 




TIC 




TIC 





just 


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+ 








— 


+ 


+ 


— 






— + — 



+ — 



+ — 



+ 



— + 



+ 






+ 



APPENDIX 



293 



TROP- TEMP- 



TEMP- 



TROPI- 



ICAL ERATE ERATE MEDI- CAL 

WEST WEST ARCTIC EAST TERR- EAST 



ATLAN- ATLAN- 



TIC 



+ 



+ 

4- 
+ 

+ 

+ 



i 



TIC 



+ 



ATLAN- ANEAN ATLAN- 



TIC 



+ — 



+ — 



just 



Pelecanus roseus, crested pelican 

fPelecanus onocrotalus , white pelican 
<^ Pelecanus erythrorhynchos , American 

(^ white pelican . . 

(Pelecanus occidentalis, brown 
J pelican 

\ Pelecanus rufescens, pink-backed 
pelican 
Sulcibassana, northern gannet 
Sula dactylatra, blue-faced booby 
Sula sula, red-footed booby 
Sula leucogaster, brown booby 
( Phalacrocorax auritus, double- 
crested cormorant 
•\ Phalacrocorax olivaceus, bigua 
I cormorant 
{^Phalacrocorax aristotelis, shag 
Phalacrocorax carbo, cormorant 
Halietor africanus, reed-cormorant 
Halietor pygmeus, pigmy cormorant 
J Anhinga rufa, African darter ^ 
^Anhinga anhinga, American darter 
Fregata magnijicens, man-o'-war-bird 
Catharacta skua, great skua 
Stercorarius pomarinus, pomarine 

skua 
Stercorarius parasiticus, arctic skua 
Stercorarius longicaudus, long-tailed 

skua 
Pagophila eburnea, ivory-gull 
Larus audouinii, Audouin's gull . . 
f Larus delawarensis , ring-billed gull 
Larus canus, 'common' gull 
Larus argentatus, herring-gull ^ . . 
Larus fuscus, lesser black-back . . 
Larus marinus, great black-back 
Larus hyperboreus, glaucous gull . . 
(Larus atricilla, laughing gull 
J Larus cirrhocephalus, grey-headed 

1 gull 

[^Larusridibundus, black-headed gull 

^ regarded as conspecific with anhinga in index list, 
^includes L. glaucoides (leucopterus) , the 'Iceland' gull. 









+ — 



TIC 



+ 



+ 



+ 



— 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


+ 


+ 


+ 














p 


+ 


+ 


+ 








? 


+ 


+ 








+ 





+ 





just 


+ 











— 


+ 


+ 


+ 


— 


— 


— 


just 


+ 
+ 


+ 


— 


— 


— 


+ 


? 


+ 


— 


— 


+ 


+ 


— 


— 


— 


+ 


+ 


+ 


+ 


+ 


— 


— 


+ 


+ 


— 


— 


— 


+ 


+ 


+ 


— 


— 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 








4- 



+ 



294 



SEA- 


BIRDS 






TROP- 


TEMP- TEMP- 




TROPI- 


ICAL 


ERATE ERATE 


MEDI- 


CAL 


WEST 


WPST ARCTIC EAST 


TERR- 


EAST 


ATLAN- 


ATLAN- ATLAN- 


ANEAN 


ATLAIS 


TIC 


TIC TIC 




TIG 



Lams pipixcan, Franklin's gull . . — inland — — — — 
Lams melanocephalus, Mediter- 
ranean black-headed gull . . — — — — + — 
Larus genet, slender-billed gull . . — — — + + ? 
Larus Philadelphia, Bonaparte's 

gull . . . . . . . . — inland — — — — 

Larus minutus, little gull . . . . — — — + — — 

Rhodostethia rosea, Ross's gull .. — — _!_** — — — 

Rissa tridactyla, kittiwake . . — + + + — — 

Xema sabini, Sabine's gull . . — just + — — — 

Chlidonias hybrida, whiskered tern — — — + + + 
Chlidonias leucoptera, white-winged 

black tern . . . . . . — — — casual casual — 

Chlidonias nigra, black tern . . — + — + + — 

Phaetusa simplex, large-billed tern + — — — — — 

Gelochelidon nilotica, gull-billed tern + + — + + ? 

Hydroprogne caspia, Caspian tern — + — + + ? 

Sterna hirundo, common tern . . + + + + + — 

Sterna paradisaea, arctic tern .. — + + + — — 

Sterna f or steri, Forster's tern . . — + — — — — 

Sterna dougallii, roseate tern . . 4- + — + + — 

Sterna anaetheta, bridled tern . . + + — — — ? 

Sterna fuscata, sooty tern . . . . + + — — — ? 

Sterna super ciliaris, yellow-billed 

river-tern .. .. ..+ — — — — — 

Sterna albifrons, little tern . . + + — + + + 

Thalasseus maximus, royal tern . . + + — ? — ? 
Thalasseus bengalensis, lesser 

crested tern .. .. .. — — — — + — 

Thalasseus eurygnatha, Cayenne 

tern .. .. .. ..+ — — — — — 

Thalasseus sandvicensis. Sandwich 

tern + + — + + — 

Anoiis stolidus, noddy . . . . + + — — — + 

Anoiis minutus, white-capped noddy + — — — — — 

C Rynchops nigra, black skimmer . . + + — — — — 
<( Rynchops Jlavirostris, African 

(^ skimmer •• .. .. — — — — — + 

Plautus alle, little auk . . . . — — + — — — 

Alca impennis, great auk . . — extinct — extinct — — 

Alca torda, razorbill . . . . — + -f + — — 

Uria lomvia, Briinnich's guillemot — + + + — — 

**only once on Atlantic side. 



Uria aalge, guillemot 
Cepphus grylle, black guillemot 
Fratercula arctica, puffin . . 



APPENDIX 








29, 


TROP- 


TEMP- 




TEMP- 




TROPI- 


ICAL 


ERATE 




ERATE 


MEDI- 


CAL 


WEST 


WEST 


ARCTIC 


EAST 


TERR- 


EAST 


ATLAN- 


ATLAN- 




ATLAN- 


ANEAN 


ATLAN' 


TIC 


TIC 




TIC 




TIC 





+ 


+ 


+ 











+ 


+ 


+ 











+ 


+ 


+ 









(ii) SECONDARY SEA-BIRDS, BREEDING 



Gavia stellata, red- throated diver 
Gavia arctica, black-throated diver 
Gavia immer, great northern diver 
Gavia adamsii, white-billed north- 
ern diver 
C Podilymbiis podiceps, pied-billed 
<( grebe . . 
[^ Podiceps ruficollis, dabchick 
Podiceps auritus, Slavonian grebe 
Podiceps nigricollis, black-necked 

grebe . . 
Podiceps cristatus, great crested 

grebe . . 
Podiceps griseigena, red-necked grebe 
Branta bernicla, brent-goose 
Tadorna tadorna, shelduck 
/ Anas penelope, wigeon 
\Anas americana, American wigeon 
f Bucephala clangula, goldeneye 
< Bucephala islandica, Barrow's 
(^ goldeneye 
Clangula hyemalis, long-tailed duck 
Histrionicus histrionicus, harlequin- 
duck 
Somateria mollissima, eider 
Somateria spectabilis, king-eider 
Somateria stelleri, Steller's elder . . 
Melanitta nigra, scoter 
Melanittafusca, velvet-scoter 
Melanitta perspicillata, surf-scoter 
Camptorhynchus labradorius, Labrador 

duck 
Mergus albellus, smew 
^ Mergus cucullatus, hooded 
•{ merganser 
[^Mergus merganser, goosander 
*casual in Atlantic sector. 



+ 
+ 
+ 



+ 
+ 



+ 
+ 
+ 



+ 



+ 



+ 
+ 
+ 






+ 



+ 


— 


— 


— 


— 


— 


— 


+ 


+ 


+ 


+ 


+ 


+ 


— 


— 


+ 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


+ 


+ 


+ 


+ 


— 


— 


— 


+ 


— 


— 


— 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


— 


— 


+ 


+ 


— 


— 


— 


— 


+ 


+ 


? 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


+ 


— 


— 


+ 


+ 


+ 


— 


— 


+ 


4- 
+ * 


z 


Z 


— 


? 


+ 


+ 


— 


— 


? 


+ 


+ 


— 


— 



+ — 



— extinct — — 



+ — — 



+ 



296 



SEA- 


BIRDS 










TROP- 


TEMP- 




TEMP- 




TROPI- 


ICAL 


ERATE 




ERATE 


MEDI- 


CAL 


WEST 


WEST 


ARCTIC 


EAST 


TERR- 


EAST 


ATLAN- 


ATLAN- 




ATLAN- 


ANEAN 


ATLAN- 


TIC 


TIC 




TIC 




TIC 





+ 


+ 


+ 











just 


+ 


just 











+ 


+ 


+ 









Mergus senator ^ red-breasted 

merganser 
Phalaropusfulicarius, grey 

phalarope 
Phalaropus lobatus, red-necked 

phalarope 

(iii) NORTH ATLANTIC NON-BREEDING VISITORS 

AND CASUALS 

Primary 

Aptenodytes patagonica, king-penguin (introduced) 

Diomedea exulans, wandering albatross 

Diomedea melanophris, black-browed albatross 

Diomedea chlororhynchos, yellow-nosed albatross 

Diomedea chrysostoma, grey-headed albatross 

Phoehetria palpebrata, light-mantled sooty albatross 

Daption capensis, Cape pigeon 

Puffinus gravis, Tristan great shearwater 

Puffinus griseus, sooty shearwater 

Pterodroma inexpectata, Peale's or scaled petrel 

Pterodroma neglecta, Kermadec petrel 

Pterodroma arminjoniana, Trinidad petrel 

Pterodroma leucoptera, collared petrel 

Oceanites oceanicus, Wilson's petrel 

Fregetta tropica, black-bellied storm-petrel 

Sula capensis. Cape gannet 

Larus californicus, California gull (perhaps a race of L. argentatus) 

Larus ichthyaetus, great black-headed gull 

Sterna trudeaui, Trudeau's tern 

Sterna balaenarum, Damara tern 

Thalasseus bergii, swift tern 

Thalasseus elegans, elegant tern 

[Gygis alba, fairy tern (probably)] 

Aethia psittacula, paroquet auklet 

Aethia cristatella, crested auklet 

Lunda cirrhata, tufted puffin 

Secondary 
Somateria fischeri, spectacled eider 

Note: Macronectes giganteus, the giant fulmar of the antarctic and subantarctic, has 
been recorded (1846 or 1847) from the Rhine near Mainz in Germany. 
Most authorities now place this record in the limbo of 'hypothetical' cases. 



BIBLIOGRAPHY 



Ornithologists have become slaves to the established system of bibliographical 
citation, under which it is the custom to cite the original authority for every fact 
quoted, with the date of publication of his work, full title of the paper, the correct 
abbreviation of the title of the journal according to the World List of Scientific Periodi- 
cals, etc., etc. As a result various scholarly and admirable books have become 
adorned with super-bibliographies the publication of which must have increased 
the setting cost of the books by at least ten per cent., sometimes by several hundreds 
of pounds. These bibliographies certainly show that the author has taken the trouble 
to go to original sources for his information, and make it very easy for other scholars 
to tread the same paths: they also, of course, give credit where it is due. Thus the 
bibliography of E. A. Armstrong (1947) contains about a thousand citations, occupy- 
ing 38 pages in smallish type; that of J. Huxley (1942) nearly a thousand, occupying 
35 P^ges; that of R. C. Murphy (1936) about a thousand occupying 32 double- 
column pages; that of F. Salomonsen (1950-51), admittedly selective, over five 
hundred occupying 18 double-column pages. If Fisher (1952) had published his 
full formal bibliography of the fulmar he would have quoted 2,378 works; if cited 
in full in smaller type than the main text of the book these would have occupied 
about 125 pages; in the smallest possible type between sixty and seventy pages. 

In the course of writing this book we have consulted about five thousand original 
notes, papers and books; our resulting collection of slips is nevertheless only a 
practical, working bibliography of the sea-birds of the North Atlantic. If we were 
to expand it to a complete bibliography we should doubtless end up with at least 
ten thousand entries, even if we rigidly confined them to purely scientific publica- 
tions. If we were to publish it as it is it might be of use to a few scholars who probably 
know more about the literature than we do; but it would certainly increase the 
price of this book beyond the reach of those for whom we intend it! 

We have therefore confined our bibliography generally to classic publications 
which (in our opinion) represent important stages in the development of human 
knowledge of North Atlantic sea-birds, and to publications particularly relevant to 
facts in the text which (in our judgment) are not common knowledge or which are 
based on research or observation of particular interest or originality. The whole 
bibliography is thus selected by subjective judgment; and disappointed scholars 
are cordially invited to correspond with us if thus frustrated. 

We would like to take the opportunity to add that, in our opinion, the time has 
come for all bibliographies to works of zoological synthesis to be selective. No 
historian today, writer of a history book of the rarest degree of specification, would 
attempt to quote the original source for every fact. But many zoological writers 
rudely interrupt their own text with cross-references to bulky triumphs of slip-index 



298 SEA-BIRDS 

work, which deserve pubUcation on their own — as original contributions to the 
science of Bibhography — or not at all. We ourselves have no feeling other than 
satisfaction in discarding nine-tenths of the slip-index we have laboriously and 
carefully compiled. 

AiNSLiE, J. A. and Atkinson, R. (1937). On the breeding habits of Leach's fork- 
tailed petrel. Brit. Birds, 30: 234-48, 276-77. 
Alexander, W. B. (1928). Birds of the ocean. New York and London, G. P. 

Putnam's Sons. 
Allen, G. M. (1931). The birds of Liberia. Report of the Harvard-African Expedition 

upon the African Republic of Liberia and the Belgian Congo, vol. /; 636-748. 
Andersen, K. (1894). Diomedea melanophrys, boende paa Faeroerne. Vidensk. Medd. 

JVaturh. Foren. Kobenhavn, i8g4: 241-64. 
Anderson, J. (1746). Nachrichten von Island, Gronland und der Strasse Davis, 

zum wahren Nutzen der Wissenschaften und der Handlung. Hamburg. 
Andree, S. a. (1931). Andree's first diary, pp. 347-412 of S. A. Andree, N. Strind- 

berg and K. Fraenkel (1931). The Andree Diaries. London, John Lane, transl. 

Edward Adams-Ray. 
Anon ( 1 838) . Gronlands historiske Mindesmaerker, udgivne af de Kong Nordiske 

Oldskriftselskab. Kjobenhavn, vol. i. 

(1952). Gannet-hunting on Sulisgeir . . . Scotsman, 27 Sep. 

Armstrong, E. A. (1940). Birds of the grey wind. London, New York and Toronto, 

Oxford University Press. 

(1947). Bird display and behaviour. London, Lindsay 

Drummond. 

Atkinson, R. and Ainslie J. A. (1940). The British breeding status of Leach's fork- 
tailed petrel. Brit. Birds, 34: 50-55. 
Audubon, J. J. (1831-39). Ornithological biography, . . . Edinburgh, 5 vols. 

(1840-44). Birds of America; from drawings made in the United 

States and their territories. New York and Philadelphia, first 8vo ed. 

Austin, O. L. Jr. (1928). Migration-routes of the arctic tern [Sterna paradisaea 
Brlinnich). Bull. N.E. Bird-Banding Assoc. 4: 121-25. 

(1932). The birds of Newfoundland Labrador. Mem. Nuttall Orn. CI. 

no. 7; 229 pp. 

(1932 onwards). Valuable papers on terns (chiefly Sterna hirundo) 



too numerous to cite, in Bird-Banding, 3 and volumes to date. 
Bailey, A. M. (1948). Birds of arctic Alaska. Colorado Mus. Nat. Hist. Popular Set. 

no. 8; 317 pp. 
Bailey, H. H. (191 3). The Birds of Virginia. Lynchburg, Va. 

(1925), The birds of Florida; . . . Baltimore, Maryland. 

Bannerman, D. a. (1930-31). The birds of tropical West Africa. London, Crown 

Agents for the Colonies (Oliver & Boyd), vols, j Sl 2. 
Bartholomew, G. A. A. (1942). The fishing activities of double-crested cormorants 
on San Francisco Bay. Condor 44: 1 3-2 1 . 

( 1 943) • The daily movements of cormorants in San Fran- 
cisco Bay. Condor, ^5; 3-18. 

(1943b). Contests of double-crested cormorants for perch- 



ing sites. Condor, 45: 186-95. 



BIBLIOGRAPHY 299 

Bartholomew, J. ( 1 950) . The advanced atlas of modern geography. London and 

New York, Meiklejohn and McGraw-Hill. 
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Longipennes. Bull. U.S. Nat. Mus. no. 113; 345 pp. 

(1922). Life histories of North American petrels and pelicans and their 



allies. . . . Bull. U.S. Nat. Mus. no. 121; 181. pp. 
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birds of Lakeland. Trans. Carlisle Nat. Hist. Soc. 6: 170 pp., publ. Arbroath, Buncle. 
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2 vols. 

(1905). Supplement to the Birds of New Zealand. London, 2 vols. 

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Chislett, R. (1952). Yorkshire Birds. London and Hull, A. Brown & Sons. 
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Scotland. Ann. Scot. Nat. Hist. i8g^: 97-108. 



300 SEA-BIRDS 

Clarke, W. E. (1898). On the avifauna of Franz Josef Land. . . . Ibis (7) 4: 249-77. 

(19 1 2). The little auk visitation of 1911-12. Scot. Nat. igi2: 77-81. 

(1912b). Studies in bird migration. London, Gurney and Jackson, 

2 vols. 

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(1949). The palatability of the eggs of birds. Ool. Rec. 23: 1-9. 

(1951-52). The palatability of the eggs of birds: . . . Proc. ^ool. Soc. Lond. 

121: I -4 1. 122: 1-54; 

(1953). The exploitation of wild birds for their eggs. Ibis, gj: 409-49, 



643-75- 
CoTTAM, C. and Uhler, F. M. (1937). Birds in relation to fishes. U.S. Bur. Biol. 

Survey, B: 5-83. 
CuRRY-LiNDAHL, K. (1947). Nagra Svenska Faglar. Stockholm, Natur och Kultur. 
Darling, F. F. (1938). Bird flocks and the breeding cycle a contribution to the 

study of avian sociality. Cambridge, University Press. 

(1947). Natural history in the Highlands and Islands. London, 

Collins' New Naturalist. 

Darwin, C. (1871). The descent of man, and selection in relation to sex. London. 

(1920). The origin of species by means of natural selection or the 

preservation of favoured races in the struggle for life. London, John Murray, 
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Davis, M. and Friedmann, H. (1936). The courtship display of the flightless 

cormorant. Sci. Monthly, 42: 560-63. 
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Quart. J. Roy. Meter eol. Soc. yi: 11-25. 
Debes, L. (1673). Faeroae et Faeroa Reserata. Copenhagen. 
Delacour, J. (1947). Birds of Malaysia. New York, the MacMillan Co. 
DeLong, E. (ed.) (1883). The voyage of the Jeannette. The ship and ice journals of 

George W. DeLong, Lieutenant-Commander U.S.N., and Commander of the 

Polar Expedition of 1 879-1 881. London, Kegan Paul, 2 vols. 
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SuDiLOVSKAYA, A. M. (1951). Ptitsy Sovetskogo Soyuza. Moskva, Gosudarstven- 

noye Izdatel'stvo "Sovetskaya Nauka," vol. /. 
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skogo Soyuza. Moskva, Gosudarstvennoye Izdatel'stvo "Sovetskaya Nauka," 

vol. 3. 
Dewar, J. M. (1939). Timing the under-water activities of diving birds. Brit. 

Birds, 38: 58-61. 
Dill, H. R. and Bryan, W. A. (19 12). Report on conditions on the Hawaiian 

bird reservation with list of the birds found on Laysan. U.S. Dep. Agric. Biol. 

Surv. Bull. no. 42; 7-24. 
Dixon, C. (1885). The ornithology of St. Kilda. Ibis (5) 3: 69-97. 
— — (1896). British sea birds. London, Bliss, Sands & Foster. 



BIBLIOGRAPHY 3OI 

Drost, R. (1939). Erfolgreiche Brut der Dreizehenmove, Rissa tridactyla (L.) auf 

Helgoland. Orn. Monatsb. 47: 179-80. 
DuFFEY, E. and Sergeant, D. E. (1950). Field notes on the birds of Bear Island. 

Ibis, 92: 554-63. 
DuTCHER, W. (1904). Report of the A.O.U. Committee on the protection of North 

American birds, for the year 1903. Auk, 21: 97. 
DwiGHT, J. (1925). The gulls (Laridae) of the world; their plumages, moults, 
variations, relationships and distribution. Bull. Amer. Mus. Nat. Hist. 52: 63-401. 
Edmunds, M. H. (1952). Albatross in Derbyshire. Field, 200: 424. 
Elliott, J. S. (1895). Observations on the fauna of St. Kilda. Zoologist (3) ig: 

281-86. 
Emerson, W. O. ( i 904) . The Farallone Islands revisited, 1 887- 1 903. Condor, 6: 6 1 -68. 
Faber, F. (1822). Prodromus der islandischen Ornithologie. Kobenhavn. 
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312 SEA-BIRDS 

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INDEX TO VERTEBRATE SPECIES 313 

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INDEX TO VERTEBRATE SPECIES IN A SYSTEMATIC 

ORDER 

Plate references in italics 

MAMMALS 

Didelphis marsupialis Linnaeus: Opossum, 77, Felis catus Linnaeus: Cat, 128, 199 

128. Pinnipedia: Seals, etc., 190, 224, 228 

Erinaceus europaeus Linnaeus: Hedgehog, 94 Odobenus rosmarus (Linnaeus): Walrus, 190, 

Chiroptera: Bats, 162, 179, 283 228 

Homo sapiens Linnaeus: Man, 65. H. neander- Phoca groenlandica Erxleben: Harp-seal, 112 

thdlensis W. King: Neanderthal man, 65 Bos taurus Linnaeus: Domestic ox, 99 

Canidae: Dogs and foxes, 128, 241, 261. Om anV^ Linnaeus: Domestic sheep, 264 

Canis familiaris Linnaeus: Dog, 98, 99, 128, Orydolagus cuniculus (Linnaeus): Rabbit, 249, 

241, 264. C. lupus Linnaeus: Wolf, 112. 264, 271 

Alopex lagopus (Linnaeus): Arctic fox, 112, Rodcntia: Rodents, 121, 149 

185, 286 Muridae: Rats, mice, etc., 121, 149, 224 

Vulpes vulpes (Linnaeus): Red fox, 112, 232 Rattus: Rats, 78, 79, 86, 94, 115, 261, 264. 

Thalarctos maritimus (Phipps): Polar bear, /?. raf/z/5 (Linnaeus): 'Black' rat, 1 12, 113. 

112, 190,228 R. norvegicus (Berkenhout) : 'Brown' rat, 

Procyon lotor (Linnaeus): Raccoon, 128 112, 113 

Mustela erminea Linnaeus: Stoat, 112, 232, Cetacea: Whales, 104, 105, 140, 187, 190, 

241 224 

Lutra lutra (Linnaeus): Otter, 112, 241 Megaptera novaeangliae (Borowski): Hump- 

Mephitis mephitis (Schreber): Skunk, 264 back, 215 

Herpestes auropunctatus (Hodgson): Small Ortmwj orca (Linnaeus): Killer-whale, 112 

Indian mongoose, 77 

BIRDS 

Archaeopteryges (ARCHAEOPTERT- Hesperornis, 33 

GIDAE): Archaeopteryx, S3 Struthiones {STRUTHIONIDAE): 

HESPERORNrrHES {HESPEHORMTHIDAE): Ostriches, 32, 33 



314 



SEA-BIRDS 



Apteryges (APTERTGIDAE): Kiwis, 33 
Casuarii 

CASUARIIDAE: Cassowaries, 33 
DROMAEIDAE: Emus, 33 
Rheae (RHEJDAE): Rheas, 33 
Crypturi ( TINAMIDAE) : Tinamous, 33 
Sphenisci {SPHEMSCIDAE):Fengiims, 32- 
35> 37, 172, 261, 267, 283 

Aptenodytes patagonica ] . F. Miller: King- 
penguin, 35, 296 

Eudyptes chrysolophus (Brandt) : Royal, or 
macaroni penguin, 35 
Spheniscus demersus (Linnaeus): Black- 
footed, or jackass penguin, 35 
TuBiNAREs: Tubenoses, 12, 17, 18, 32-35, 
52, 127, 131, 133, 157, 162, 167, 170, 
178-96 

DIOMEDEIDAE Albatrosses, 27, 32, 33, 
35, 126, 127, 175, 178, 183, 184, 187, 
188, 194 
Diomedea exulans Linnaeus: Wandering 
albatross, 28, 192, 296. D. epomophora 
Lesson: Royal albatross, 182, 190, 192. 
D. melanophris Temminck: Black- 
browed albatross, 27, 28, 296. D. bulleri 
Rothschild: BuUer's mollymawk, 273. 
D. chlororhynchos Gmelin: Yellow-nosed 
albatross, 28, 296. D. chrysostoma 
Forster: Grey-headed albatross, 28, 296. 
Phoehetria palpebrata (Forster): Light- 
mantled sooty albatross, 28, 296 
PROCELLARIIDAE: Petrels, 32, 35, 37, 
116, 126, 131, 158, 163, 175, 176, 179, 
181, 182, 193, 209, 237, 247, 286 
Hydrobatinae: Small storm-petrels, 33, 

120, 178, 179, 182, 193 
Oceanites oceanicus (Kuhl): Wilson's 
petrel, 8, 27, 61, 157, 168-69 map, 181, 

183, 187-89, 191-94, 296 
Pelagodroma marina (Latham): Frigate- 
petrel, 19, 20, 23, 133, 181, 187-89, 

191-93, 292 

Fregetta tropica (Gould): Black-bellied 
storm-petrel, 29, 296. 
Hydrobates pelagicus (Linnaeus): (Atlan- 
tic) Storm-petrel, 16, ly, 19, 20, 23, 34, 
no, 120, 133, 138, 162, 181, 183 map, 

184, 187-93, 292 

Oceanodroma castro (Harcourt) : Madeiran 
fork-tailed, or Madeiran storm-petrel, 
19, 20, 23, 112^ 186 map, 187, 292. 
0. leucorhoa (Vieillot): Leach's petrel, 8, 
13, 14, 16, 17, 23, 58, 112, 120, 133, 138, 
184, 186 map, 187-89, 191-93, 292 
PROCELLARIINAE: Fuhnars, prions, 
gadfly petrels and shearwaters, 12, 32, 
33,35, 119,131,133,158, 160, 170, 172, 
178, 179, 183, 187, 195, 198, 220, 221 
Macronectes giganteus (Gmelin): Giant 
fulmar, stinker, 296. 



Daption capensis (Linnaeus): Cape 
pigeon, 28, 296 

Fulmarus glacialis (Linnaeus) : Fulmar, 14 
18, 23, 35, 38, 45-47, 52-58, 54 map, 61, 
63, 64, 93, 95, 97, 98, 100, loi, 103-07, 
106 map, III, 114, 115, 118, 119, 122, 
133, 135, 138, 160, 163, 170, 174, 179, 
183-85, 187-90, 192, 195, 223, 224, 
239, 289, 292, 297 

Puffinus diomedea (Scopoli)=^«A/» (Boie): 
North Atlantic, or Cory's shearwater, 
19, 20, 23, 26, 58, 113, 133, 185, 187, 

188, 292. P. gravis (O'Reilly): Tristan 
great shearsvater, 8, 26, 27, 58, 61, gy, 
107, 133, 139, 157, 163, 170, 183, 187, 

189, 192, 194, 195, 296. P. griseus 
(Gmelin): Sooty shearwater, 26, 27, 
107, 133, 139, 157, 296. P. puffinus 
(Briinnich): Manx shearwater, 12, 16, 
17, 19, 20, 23, 34, 94, 96,97, lOI, iio- 
14, 113, 133, 139, 158-63, 161 map, 174, 
181, 183, 184, 187-89, 191-96, 213, 
228, 241, 249, 292. P. assimilis Gould: 
Little (dusky) shearwater, 19, 20, 23, 
78, 162, 180 map, 181, 183, 184, 188, 
189, 192, 292. P. I'herminieri Lesson: 
Audubon's shearwater, 9, 12, 23, 78, 
180 map, 181, 292. 

Pterodroma macroptera (A. Smith): Mut- 
ton-bird, 193. P. hasitata (Kuhl): 
Diablotin, or capped petrel, 10, 12, 23, 
34, 76, 77, 292. P. cahow (Nichols and 
Mowbray): Cahov/, frontispiece, 12, 23, 
34, 58, 61, 76-79, 292. P. inexpectata 
(J. R. Forster) : Peale's, or scaled petrel, 

28, 296. P. neglecta (Schlegel): Ker- 
madec petrel, 28, 296. P. arminjoniana 
(Giglioli and Salvador!): Trinidad 
petrel, 29, 296. P. mollis (Gould): Soft- 
plumaged petrel, 19, 20, 23, 292. 
P. leucoptera (Gould): Collared petrel, 

29, 296 

Bulweria bulwerii (Jardine and Selby): 

Bulwer's petrel, 19, 20, 23, 132, 133, 

187, 188, 191, 193, 292 
PELECANOIDIDAE: Diving-petrels, 33, 

267 
PoDiciPiDEs (PODICIPITIDAE) : Grebes, 
22, 32, 33, 36, 166 

Poliocephalus ruficollis (Pallas) : Dabchick, 

23, 295 

Podiceps auritus (Linnaeus) : Slavonian, or 

horned grebe, 23, 295. P. nigricollis 
C. L. Brehm: Black-necked, or eared 
grebe, 23, 295. P. cristatus (Liimaeus): 
Great crested grebe, 23, 166, 295. 
P. griseigena (Boddaert): Red-necked 
grebe, 23, 295. 

Podilymbus podiceps (Linnaeus): Pied- 
billed grebe, 23, 295 



INDEX TO VERTEBRATE SPECIES 



315 



Gaviae (GAVIIDAE): Divers or loons, 22, 
32-34, 36, 120, 131 

Gavia stellata (Pontoppidan): Red- 
throated diver, 23, 295. G. arctica (Lin- 
naeus): Black-throated diver, 23, 295. 
G. immer (Briinnich): Loon, or great 
northern diver, 23, 114, 295. G. adamsii 
(G. R. Gray): White-billed northern 
diver, 23 ,25, 295 
Steganopodes: Steganopodes, or pelecani- 

form birds, 32-35, 37, 170, 197-221 

PHAETHONTIDAE: Tropic-birds, 8, 9, 
33> 35» 120, 197, 199, 211 
Phaethon aethereus Linnaeus: Red-billed 
tropic-bird, 19, 20, 23, 217 map, 220, 
22 1', 292. P. lepturus Daudin: White- 
tailed tropic-bird, 12, 19, 21, 23, 217 
map, 220, 221, 293 

FREGATIDAE: Frigate-, or man-o'-war 
birds, 9, 33, 35, 120, 197, 200, 204, 206, 
210, 212 

Fregata magnificens Mathews: Magnifi- 
cent frigate-bird, 9, 10, 19-21, 23, 198, 
199, 204, 205, 218-20, 228, 293 

PHALACROCORACIDAE: Cormorants 
and Darters 

Phalacrocoracinae: Cormorants, 32, 33, 
35» I7i» 197, 204, 210, 212, 213, 
215, 218, 245 

Phalacrocorax auritus (Lesson): Double- 
crested cormorant, 10-14, 23, 58, 61, 
197, 198, 204, 205, 206 map, 212, 215, 
287, 293. P. olivaceus (Humboldt): 
Mexican, or bigua cormorant, 8-1 1, 23, 
206 map, 293. P. sulcirostris (Brandt): 
Little black cormorant, 198. P. car bo 
Lirmaeus: (Common, European) Cor- 
morant, 13, 15-20, 23, 58, 114, 117, 118, 
131, 184, 199, 201, 205-07, 209, 21 1-15, 
214 map, 293. P . penicillatus (Brandt): 
Brandt's cormorant, 205. P. aristotelis 
(Linnaeus): Shag, 15-17, I9> 21, 23 34, 
g2, 96, 118, 131, 184, 197-99, 201, 
204-06, 206 map, 209, 211, 212, 293. 
P. bougainvillii (Lesson): Guanay, 198, 

215 

Halietor africanus (Gmelm): Reed-cor- 
morant, 19, 21-23, 20G map, 293. 
H. pygmeus (Pallas): Pigmy cormorant, 
18, 19, 25, 293 

Nannopterum harrisi (Rothschild) : Flight- 
less cormorant, 213 
Anhinginae: Darters, 33, 35, 197 
Anhinga anhinga (Linnaeus): Darter, 
water-turkey, snake-bird, 10, 11, 19, 
21-23, 293 
SULIDAE: Gannets, boobies, 8, 9, 32, 33, 
35» i97> 199-201, 206, 209-11, 219, 245 
Sula bassana (Linnaeus) : Northern gannet, 
13, 14, 16-18, 23, 34, 52,55, 56-58, 61, 



64, 70, 79-85, 80 graph, 84, 93, 94, 
97-102, 107, no. III, 122, 124, 131-33, 
135, 138, 141, 158, 163, 167, 170-74, 
176, ig6, IQ7, 200-13, 202 map, 203 
map, 216, 218, 223, 229, 241, 242, 254, 
269, 270, 276, 293. S. capensis (Lich- 
tenstein): Cape gannet, 29, 203 map, 
215, 296. S. senator (G. R. Gray): 
Australasian gannet, 203 map. S. dactyl- 
atra Lesson: Blue-faced booby, 23, 120, 
131, 132, 140, 212, 216-78, 217 map, 
293. S. sula (Linnaeus): Red-footed 
booby, 9, 10, 23, 120, 131, 216-20, 217 
map, 293. S. leucogaster (Boddaert): 
Brown booby, 8, 10, 19-21, 23, 120, 
133, 140, 216-18, 217 map, 293 
PELECANIDAE: PeHcans, 35, 197, 199, 
204, 205, 208-10, 212 
Pelecanus onocrotalus Linnaeus: White 
pelican 19, 21-23, 293. P. rufescens 
Gmelin: Pink-backed, or grey pelican, 
19, 21-23, 293. P. roseus Gmelin: 
Crested pelican 18, 19, 25, 293. 
P. erythrorhynchos Gmelin: American 
white pelican, 11, 23, 58, 61, 198, 293. 
P. occidentalis Linnaeus: Brown pelican, 
9-12, 23, 85, 197-201, 215, 216, 293 
Falcones: Diurnal birds of prey, 33 

ACCIPITRIDAE: Hawks, eagles, etc., 
162, 193, 232 

Accipiter gentilis (Linnaeus): Goshawk, 
112. A. nisus (Linnaeus): Sparrow- 
hawk, 1 1 2 

Buteo buteo (Linnaeus): Common buz- 
zard, 112 

Aquila chrysaetos (Linnaeus): Golden 
eagle, 1 1 2 

Haliaeetus leucocephalus (Linnaeus): Bald 
eagle, 112. H. albicilla (Linnaeus): 
White-tailed eagle, 112, 236. 
Circus cyaneus (Linnaeus): Hen-harrier, 
117. C. aeruginosas (Linnaeus): Marsh- 
harrier, 1 1 2 
FALCONIDAE: Falcons 

Falco rusticolus Linnaeus: Gyr-falcon, 
112. F. peregrinus Tunstall: Peregrine, 
no. F. columbarius Linnaeus: Merlin, 
112. 
CATHARTIDAE: New World vultures 
Coragyps atratus (Bechstein): Black vul- 
ture, 219 
Gressores: Herons, ibises and storks, 33 
ARDEIDAE: Herons, 33 

Ardea cinerea Linnaeus: Heron, 205, 264 
THRESKIORNITHIDAE: Ibises, etc., 33 
Platalea leucorodia Linnaeus: Spoonbill, 
205 
CICONIIDAE: Storks, 33 
Phoenicopteri {PHOENICOPTERIDAE): 
Flamingos, 33 



3i6 



SEA-BIRDS 



Anseres: Anatids and screamers 
ANATIDAE: Anatids, 22, 33, 36 
Anserinae : Geese, swans and tree-ducks, 

33» 36 
Branta bernicla (Linnaeus): Brant, or 
brent-goose, 25, 295 
Anser: Bean- and pink-footed geese: 
228, 236. A. albifrons (Scopoli): White- 
fronted goose, 236. A. anser (Linnaeus), 
Grey-lag goose, 166 

Cygnus columbianus (Ord) : Whistling and 
Bewick's swans, 236 
Anatinae: Shelducks and ducks 32-34, 

36, 119, 201, 247 
Tadorna tadorna (Linnaeus): (Common) 
Shelduck, 295 

Anas penelope Linnaeus: (European) 
Wigeon, 295. A. americana Gmelin: 
American wigeon, 295 
Somateria mollissima (Linnaeus); (Com- 
mon) Eider, 23, 38, 10 1, 119, 131, 295. 
S. spectabilis (Linnaeus): King-eider, 23, 
295' S. fischeri (Brandt): Spectacled 
eider, 26, 296. S. stelleri (Pallas): Stel- 
ler's eider, 23, 25, 295 
Camptorhynchus labradorius (Gmelin) : 
Labrador duck, i, 25, 76, 295 
Melanitta nigra (Linnaeus): (Common) 
Scoter, 23, 114, 131, 295. Al.perspicillata 
(Linnaeus): Surf-scoter, 23, 295. A/. 
jfusca (Linnaeus): Velvet-, or white- 
winged scoter, 23, 295 
Histrionicus histrionicus (Linnaeus): Har- 
lequin-duck, 295 

Clangula hyemalis (Linnaeus): Long- 
tailed duck, old-squaw, 23, 236, 295 
Bucephala islandica (Gmelin): Barrow's 
goldeneye, 295. B. clangula (Linnaeus): 
(Common) Goldeneye, 295 
Mergus albellus\AnmitVi&'. Smew, 23, 295. 
A/, cucullatus Linnaeus: Hooded mer- 
ganser, 23, 295. M. serrator Linnaeus: 
Red-breasted merganser, 23, 114, 296. 
A/, merganser Linnaeus: Goosander, 
American merganser, 23, 295 
ANHIMIDAE: Screamers, 33 

Galli {PHASIANIDAE): Game-bu-ds, 33 
Phasianinae: Pheasants and fowl 
Callus gallus (Linnaeus) : Domestic fowl 
and jungle-fowl, 165, 170 
Tetraoninae: Grouse 
Lyrurus tetrix (Linnaeus) : Black grouse, 
516 

Lagopus lagopus (Linnaeus): Willow- 
grouse, 236 

Grues: Cranes, bustards, rails, etc., 33 
GUIDAE: Cranes, 33 
OTIDIDAE: Bustards, 33 
RALLIDAE: Rails, 33 

Fulica atra Linnaeus: Coot, 201 

Laro-limicolae: Waders, gulls and auks, 



A 



32, 33, 222-89. 
CHIONIDIDAE: Sheathbills, 35 
HAEMA TOPODIDAE: Oystercatchers 
Haematopus ostralegus Linnaeus: Oyster- 
catcher, 96, 175. 
CHARADRIIDAE: Waders, 22, 32, 33, 
36, 198, 267 
Charadriinae: Plovers 
Charadrius squatarola (Linnaeus): Grey 
plover, 236. C. dominicus P. L. S. 
Miiller: American (Asiatic) golden 
plover, 236 
Scolopacinae: Sandpipers, etc. 
Capella gallinago (Linnaeus): Snipe, 236 
Calidris acuminata (Horsfield): Siberian 
pectoral, or sharp-tailed sandpiper, 236. 
C. alpina (Linnaeus): Dunlin, 236. C. 
testacea (Pallas): Curlew-sandpiper, 236. 
Philomachus pugnax (Linnaeus): Ruff, 

165, 236 

Phalaropinae: Phalaropes, 34, 36, 133, 
139, 151, 224 

Phalaropus fulicarius (Linnaeus): Grey or 
red phalarope, 23, 151-54, 154 map, 
156, 236, 296. P. lobatus (Linnaeus): 
Red-necked, or northern phalarope, 23, 
152, 153. 155 inap, 156, 236, 296 
Steganopus tricolor Vieillot: Wilson's 
phalarope, 151 
LARIDAE: Skuas, gulls and terns, 33, 35, 

166, 267 

Stercorariinae: Skuas, 18, 32-34, 36, 
47, 52, 120, 133, 139, 143, 170, 171, 
176, 199, 200, 222-26, 228, 245, 247, 
254, 263, 279, 288 

Catharacta skua Briinnich: Great skua, 
bonxie, 8, 16, 17, 23, 36, 52, 58 no, 
III, 136-37 map, 143, 144, 146, 185, 
200, 2og, 222-25, 242, 248, 293 
Stercorarius pomarinus (Temminck) : 
Pomarine skua, 1 4, 1 5, 1 7, 23, 45, 52, 1 1 2, 
120, 121, 145, map 145-47, 149,200,222 
-25, 293. S. parasiticus (Linnaeus) : Arctic 
skua, 14-17,23, 45, 52, 53 map, no in. 
120, 121, 147-50, 148 map, 200, 205, 
208, 222-26, 242, 248, 293. S. longi- 
caudus W\&\\oV. Long-tailed skua, 14, 15, 
17, 23, 45, 52, 112, 120, 121, 147, 149, 
150 map, 151, 222-25, 242, 248, 293 

Larinae: Gulls, 12, 16, 17, 32, 34-37, 85, 
105, 113, 114, 1 19-21, 127, 128, 131, 
133, 138, 144, 158, 162, 167, 170-73, 
I75» I93» 216, 219, 222, 224, 226-50, 
252, 253, 255, 257, 258, 262-264, 269, 
279, 281, 288 

Pagophila eburnea (Phipps): Ivory-gull, 
14, 155 23, 25, 119, 227, 233 map, 234> 
237, 239, 293 

Larus leucophthalmus Temminck: White- 
eyed gull, 243 map. L. audouinii Pay- 
reaudeau: Audouin's gull, 18, 19, 34, 



INDEX TO VERTEBRATE SPECIES 



317 



244 map, 293. L. delawarensis Ord: 
Ring-billed gull, 13, 14, 23, 43, 44 map, 
58, 121, 228, 264, 293. L. canus Lin- 
naeus: Common, short-billed, or mew- 
gull, 13. 15-17, 23, 43, 44 map, 58, 121, 

228, 232, 234, 242, 248, 250, 256, 293. 
L. calif ornicus Lawrence: California gull, 
29, 38-41, 41 map, 296. L. argentatus 
Pontoppidan: Herring-gull (inch Ice- 
land gull), 13-19, 21, 23, 29, 38-43, 41 
map, 59, 63, 104, III, 112, 114, 115, 
120-22, 132, 133, 172, 173, 175, 184, 
207, 225, 228-33, 22g, 236, 237, 241, 242, 
246-50, 253, 281, 282, 293. L. fuscus 
Linnaeus: Lesser black-backed gull, 
15-18, 23, 34, 38-42, 41 map, 59, 104, 

111, 115, 120, 121, 132, 133, 138, 207, 
223, 229, 231-33, 241, 242, 246-50, 293. 
L. occidentalis Audubon: Western gull, 
45 map. L. schistisagus Stejneger: Slaty- 
backed gull, 45 map. L. marinus Lin- 
naeus: Great black-backed gull, 13-18, 
235 34> 42, 435 45 inap, 59, 104, 105, 1 1 1, 

112, 120-22, 124, 133, 207, 228, 231-33, 
241, 242, 246-50, 282, 293. L. glau- 
cescens Naumann : Glaucous-winged gull, 
45 map. L. hyperboreus Gunnerus: 
Glaucous gull, 14-16, 23, 42, 43, 45 
map, 63, III, 119-22, 185, 236, 242, 
247, 250, 293. L. ichthyaetus Pallas: 
Great black-headed gull, 29, 296. L. 
atricilla Linnaeus: Laughing gull, 11, 12, 
23, 59, 1 15> 224, 228, 231, 2^0, 243 map, 

293. L. brunneicephalus Jerdon: Brown- 
headed gull, 243 map. L. cirrhocephalus 
Vieillot: Grey-headed gull, 19, 21, 23, 
1 14, 243 map, 293. L. serranus Tschudi: 
Andean gull, 243 map. L. pipixcan 
Wagler: Franklin's gull, 13, 23, 25, 243 
map, 294. L. melanocephalus Temminck: 
Mediterranean black-headed gull, 18, 
19, 25, 243 map, 294. L. maculipennis 
Lichtenstein: Brown-hooded gull, 243 
map. L. ridibundus Linnaeus: Black- 
headed gull, 16-19, 23, 56, 59, 104, 1 12, 

229, 232, 240, 241, 242, 247, 248, 250, 
253? 293. L. genei Breme: Slender- 
billed gull, 18, 19, 21, 294. L. Phila- 
delphia (Ord): Bonaparte's gull, 13, 23, 
25, 104, 236, 237, 241, 243 map, 294. 
L. minutus Pallas: Little gull, 16, 23, 59, 
104, 257, 244 map, 294. L. saundersi 
(Swinhoe): Saunders's gull, 243 map. 
Rhodostethia rosea (MacGillivray) : Ross's, 
or rosy gull, 14, 15, 23, 25, 227, 234-37, 

239, 294 

Rissa tridactyla (Linnaeus): Kittiwake, 
i3-i7> 23, 53, 59, 63, 84, 92, loi, 102. 
Ill, 112, 118, 133, 184, 223, 226, 227, 
238-40, 238 map, 242, 245, 247-49, 

294. R. brevirostris Bruch: Red-legged 



kittiwake, 238 map 

Xema sabini (J. Sabine): Sabine's gull, 
i4» 15, 23, 227, 232, 233, 237-39, 238 
map, 241, 242, 294 
Sterninae: Terns, 9-12, 16-18, 23, 32, 
34> 36, 37, 84, 85, loi, 103, III, 112, 
120, 131, 135, 144, 158, 159, 170-72, 
176, 216, 224, 226, 228, 229, 232, 234, 
237, 245, 251-66 

Chlidonias hybrida (Pallas): Whiskered 
tern, 16, 19, 21, 23, 59, 252, 254, 261, 
294. C. leucoptera Temminck: White- 
winged black tern, 16, 19, 59, 114, 252, 
254, 261, 294. C. nigra (Linnaeus): 
Black tern, 16, 19, 23, 59, 252, 252-54, 

260, 260-62, 264 map, 265 map, 294 
Phaetusa simplex (Gmelin): Large-billed 
river-tern, 8, 23, 294 

Gelochelidon nilotica (Gmelin): Gull- 
billed tern, 8, 10-12, 16, 19, 21, 23, 59, 
84, 85, 117, 252, 254, 256, 261, 26g, 294 
Hydroprogne caspia (Pallas) : Caspian tern, 

11, 13, 14, 16, 20, 21, 23, 59, 87, 252, 
254, 261, 294 

Sterna aurantia J. E. Gray: Common 
river-tern, 251. S. hirundinacea Lesson: 
South American tern, 141. S. hirundo 
Linnaeus: Common tern, 11, 12, 14-16, 

19, 20, 23, 43, 46 map, 59, 60, 85-88, 
88 map, 112, 117, 118, 120, 140, 143, 
251, 253, 254, 261, 263, 266, 294. S. 
paradisaea Pontoppidan: Arctic tern, 

13-16, 18, 23, 43, 46 map, 60, 87-89, 
88 map, 118, 120, 133, 139-43, 142 
map, 149, 157, 162, 233, 236, 251-54, 

261, 263, 265, 266, 294. iS". vittata 
Gmelin: Antarctic tern, 141. S.forsteri 
Nuttall: Forster's tern, 11, 12, 23, 43, 
46 map, 120, 252, 255, 294. S. trudeaui 
Audubon: Trudeau's tern, 29, 151, 296. 
S. dougallii Montagu: Roseate tern, 10- 

12, 17, 20, 23, 60, 87, 89, 90 map, 245, 
252-54, 261, 294. S. melanogaster Tem- 
minck: Black-bellied tern, 251. S. anae- 
theta Scopoli: Bridled tern, 10, 20, 21, 
23, 253, 254, 262, 294. S. fuscata Lin- 
naeus: Sooty tern, 9-1 1, 20, 21, 23, 60, 
84, 158, 251, 253, 254, 261, 262, 294. 
S. superciliaris Vieillot: Yellow-billed 
river-tern, 8, 23, 251, 294. S. balaenarum 
(Strickland): Damara tern, 29, 296. 
S. albijrons Pallas: Little tern, 10, 17, 18, 

20, 21, 23, 84, 85, 103, 104, 112, 115, 
117, 252, 254, 259 map, 260, 261, 263, 

294 . . O T 

Thalasseus bergii (Lichtenstein): Swift 
tern, 29, 296. T. maximns (Boddaert): 
Royal tern, 11, 20, 21, 23, 84, 85, 115, 
253, 254, 257, 262, 294. T. bengalensis 
(Lesson): Lesser crested tern, 18, 20, 25, 
294. T. eurygnatha (Saunders) : Cayenne 



3i8 



SEA-BIRDS 



tern, 294. T. elegans (Gambel) : Elegant 
tern, 29, 296. T. sandvicensis (Latham): 
Sandwich, or Cabot's tern, 10, 11, 17, 
20, 23, 34, 60, 85, 86, 89, 91 graph, 92, 
93, iHj "75 118, 232, 238, 245, 248, 
253^ 254, 258 map, 261, 266 
Procelsterna cerulea (F. D. Bennett) : Grey 
ternlet, 251 

Anoiis stolidus (Linnaeus): Noddy, 8, 9, 
II, 20, 21, 23, 60, 158, 251, 254, 256, 
262, 263, 268, 294. A. tenuirostris 
(Temminck): White-capped noddy, 8, 
9, 23, 251, 294 

Gygis alba (Sparrmann) : Fairy tern, 29, 
84, 251, 296 

RTNCHOPIDAE: Skimmers, 33, 34, 36 
Rynchops nigra Linnaeus : Black skimmer, 
8, II, 23, 253, 254, 262, 26g, 294. R. 
fiavirostris Vieillot: African skimmer, 
20-23, 294 

ALGID AE: Auks, 32-34, 36, 37, 52, 85, 98, 
100, III, 127, 132, 133, 170, 171, 175, 
176, 228, 241, 247, 255, 267-89 
Plautus alle (Linnaeus): Little auk, or 
dovekie, 14-17, 23, 25, 60, 62, 63, 119, 
122, 123, 127-34, 130 map, 132 map, 
134 map, 268, 269, 271-73, 273, 276, 
277, 281, 283, 286, 294 
Alca impennis Linnaeus: Great auk, 25, 
34» 53> 65-76, 65 fig., 68 map, 122, 267, 
268, 272, 281, 282, 294. A. torda Lin- 
naeus: Razorbill, 12, 14-18, 23, 34, 44, 
53, 60, 65, 66, 70, 95-97> 100, 10 1, 107, 
108, 113, 114, 119, 122, 132, 139, 172, 
174, 184, 267-79, 270 map, 272, 277, 
281, 282, 284, 286, 289, 294 
Uria lomvia (Linnaeus): Briinnich's or 
arctic guillemot (murre), 13, 15-17, 23, 
43. 44j 47 map, 61-63, loi, 102, 112, 
114, 119, 120, 122, 267, 271, 272, 278, 
286, 28g, 294. U. aalge (Pontoppidan) : 
(Common) Guillemot or murre, 13-17, 
20, 23, 43, 45, 47-53, 47 map, 50 map, 
51 map, 60, 61, 73, 93, 95-97, 96, 
100-02, 107-09, 111-14, 119, 120, 122, 
i33> i35> 139, i72-75> 183, 184, 204, 
261, 267-76, 272, 279, 281-85, 287- 
289, 288, 295 

Cepphus grylle (Linnaeus): Black or 
pigeon-guillemot, tystie, 12, 14-18, 23, 
38, 61, 114, 119, 131, 132, 246, 248, 
267, 271-75, 273, 274 map, 277, 278, 
281, 282, 286, 289, 295. C. carbo Pallas: 
Black-winged guillemot, 274 map 
Synthliboramphus antiquus (GmclLn) : 
Ancient murrelet, 29 
Ptychoramphus aleuticus (Pallas); Cassin's 



auklet, 268 

Aethia psittacula (Pallas) : Paroquet auk- 
let, 29, 268, 296. A. cristatella (Pallas): 
Crested auklet, 29, 268, 296. A. pusilla 
(Pallas) : Least auklet, 29, 268. A.pygmaea 
(Gmelin): Whiskered auklet, 268 
Cerorhinca monocerata (Pallas) : Rhinoceros 
auklet, 268 

Fratercula arctica (Linnaeus): (Atlantic) 
Puffin, 12, 14-18, 23, 34, 38, 61, 63, 64, 
93> 95-98, 10Q-02, 107, no, III, 113, 
114, 119, 131-33, 163, 167, 170-73, 
175, 228, 229, 241, 246, 249, 267, 269, 
271-73, 275-82, 278 map, 280 map, 
284, 286-89, 295. F. corniculata (Nau- 
mann): Horned puffin, 278 map, 286, 
287 

Lunda cirrhata (Pallas): Tufted puffin, 
29. 98, 287, 296. 
Mancalla, 34 

PsiTTACi {PSITTACIDAE): Parrots, 115 
Melopsittacus undulatus (Shaw): Budgeri- 
gar, 174 

Striges (STRIGIDAE): Owls, 33, 162, 261 
Bubo bubo (Linnaeus): Eagle-owl, 112 
Nyctea scandiaca (Linnaeus): Snowy owl, 
112 

Athene noctua (Scopoli): Little owl, no, 
162 

Asio Jlammeus (Pontoppidan): Short- 
eared owl, no, 264 

Caprimulgi (STEATORMTHIDAE): Oil- 
bird 

Steatornis caripensis Humboldt: Oil-bird, 
162 

Macrochires (APODIDAE): Swifts 

Apus apus (Linnaeus j: Swift, 181, 182 

HIRUNDINIDAE: Swallows 

Hirundo rustica Linnaeus: Swallow, 159, 

179 
MUSCICAPIDAE: Flycatchers, etc. 

Troglodytestroglodytes (Linnaeus): Wren, 

284 
STURNIDAE: Starlings 

Sturnus vulgaris Linnaeus: Starling, 160, 

198 
CORVIDAE: Crows, etc., 128, 232 

Gorvus corax Linnaeus: Raven, no, 128. 

G. corone Linnaeus: Carrion-crow, no. 

C. cornix Linnaeus: Hooded crow, no. 

G. frugilegus Linnaeus: Rook, 228, 229 
FRINGILLIDAE: Finches, Buntings, etc. 

Plectrophenax nivalis (Linnaeus): Snow- 
bunting, 236 

Garduelis hornemanni (HolboU): Arctic 

redpoll, 236. 



REPTILES 117,261. AMPHIBIANS, 255 FISH, 79, 104, 105, 107, in' 

113, 114, 117-22, 185, 190, 191, 197-201, 207-10, 212, 215, 216, 219, 220, 223, 224, 226' 
228, 245, 247, 254, 255, 260, 266, 276, 283-85, 287 



INDEX TO AUTHORITIES 



Those mentioned only in the BibHography are not listed 



AiNSLiE, J. A., 58, 187, 192. 
Allen, R. P., 58. Amadon, 
D., 33. Andersen, K., 28. 
Anderson, J., 73. Andree, 
S. A., 236. Anon>-mous, 75, 
99. Armstrong, E. A., 275, 
276, 278. Atkinson, R., 58, 
187, 192, Audubon, J. J. L., 
9, 29, 19, 252. Austin, O. L., 
Jr., 59, I39> 140, 253, 260. 
Bailey, A. M., 237. Bar- 
tholomew, G. A. A., 204. 
Bartsch, P., 60. Beck, R. H., 
77. Beebe, W., 78. Bent, 
A. C, 26, 61, 84, 187, 224, 
239, 253, 262, 286. Bertelsen, 
A., 56. Bertram, G. C. L., 58, 
62, 139. Bierman, W. H., 
141, 151. Blezard, E., 61. 
Bowdish, B. S., 10. Brand- 
sson, J., 75. Breuil, H., 65. 
Brower, C. D. 237. Brown, 
R. H., 248. Bryan, W. A., 
60. Buchan, A., 70. Buckley, 
T. E., 71. Buller, W. L., 220. 
Bullock, W., 71. Burleigh, 
T. D., 58-60, 67. Bute, the 
Marquess of, 289. Buturlin, 
S. A., 236. 

Cartier, J., 67. Cartwright, 
G., 67. Casteret, N. 283. 
Clancey, P. A., 28. Clark, 
G., 65, 66. Clarke, W. E., 
96, 129, 132, 234. Clemens, 
L., 75. Collinge, W. E., 118. 
Conder, P. J., 273. Connell, 
R., 95, 96. Cooke, R., 59, 
262. Cott, H. B., 94, 192. 
Cottam, C., 199. Coward, 
T. A., 193. Curry-Lindahl, 

K., 35- 

Danells, D., 75. Darling, 

F. F,, 174, 270, 278. Darwin, 
C, 8, 61, 165. Debes, L., 71. 
Delacour, J., 152. DeLong, 

G. W., 235- Dewar, J. M., 
201. Dill, H. R., 60. Dixon, 
C, 94-96, Dobson, R., 240. 
Drost, E., 59. Duffey, E., 26, 
59, 127, 135, 153, 266, 289. 
Edmunds, M. H., 28. Ekblaw, 
W. E., 286. Elliott, H. F. I., 
28. Elliott, J. S., 96. Elton, 
C, 62. Erik the Red, 75. 



Faber, F., 73, 74, 268. Falla, 
R. A., 193, 252. Feilden, 
H. W., 72, 77. Ferdinand, 
L., 58. Ferguson, A., 98. 
Fischer, F., 42. Fisher, J., 4, 
26, 27, 47, 49, 54, 56-61, 74, 
79-81,96, 105, 106, 113, 114, 
118, 135, 149, 183, 184, 189, 
190, 194, 195, 224, 287, 289, 
291, 297. Fleming, C A., 
145, 148, 155. Forbush, 

E. H., 58. Formosov, A. N., 
117. Foster, R. J., 276. 
Foulis, W., 71. Frazar, 
M. A., 59. 

Gatke, H., 279. Gause, 
G. F., 115, 117, 118, 122. 
Geroudet, P., 58. Gibson, 
J. A., 108, 113. Giesecke, 
K. L., 56. Glauert, L., 162, 
189, 192. Glegg, W. E., 35, 
114, 248. Godwin, 79. 
Goethe, F., 228, 231. Graba, 

C. J., 72. Gray, D., 27, 28. 
Grieve, S., 73, 75, 76. Griffin, 

D. R., 158, 162. Grinnell, 
J., 239. Griscom, L., 153. 
Gross, A. O., 58, 59, 105, 
189,220,253. Gurney,J. H., 
200, 212. 

Haddow, a. J., 118, 199. 
Hdkonarsson, V., 74. Hall, 

F. T., 78. Hansen, C, 75. 
Hantzsch, B., 139. Harris- 
son, T. H., 59, 105. Hartley, 
C. H., 118. Harvue-Brown, 
J. A., 28, 71. Haverschmidt, 
F., 205, 212. Hawksley, O., 
140. Heathcote, N., 96. 
Heinroth, O., 248. Hewitt, 
O. H., 59. Hock, R.J., 158. 
Hollom, P. A. D., 57, 59. 
Holm, G., 75. Holmes, P. F., 
156. Hore, R., 67. Horre- 
bow, N., 73. Horring, R., 
42, 43, 52, 139. Howard, H., 
32-34. Hughes-Onslow, G., 
28. Hurrell, H. G., 59, 105. 
Hutchinson, G. E., 215. 
Huxley, J. S., 37, 38, 166, 

297- ^ ^ 

VAN Ijzendoorn, A. L. J., 

57-60. Islefsson, S., 75. 

Jackson, F. G., 235. Jesper- 



sen, P., 57,60, 135, 151, 153. 
Johansen, F. H., 235. 
Johnson, R. A., 61, 269, 276, 
279, 281. Jones, J. M., 78. 
Jourdain, F. C. R., 248, 249. 
Kay, G. T., 200, 201, 211, 
284. Keighley, J., 248, 249, 
281, 284. Ketilsson, K., 75. 
King, D., 71. Kirkman, 
F. B., 229, 242, 244 246. 
Kolthoff G., 139. Kramer, 
G., 160. Krasovskii, S. K., 
63. Kritzler, H., 185. 
Kumlien, L., 29. 
Labat, J. B., 76, 77. Lack, 
D., 58, 62. 115, 116, 118, 139. 
Landt,J., 72. Lashley K. S., 
158. Lawrence, G. N., 77. 
Lethbridge, T. C, 139. 
Lewis, H. F., 49, 58, 59, 61, 
205, 212. Lockley, R. M., 
26, 27, 49, 56, 58, 60, 61, 64, 
83, 89, 114, 116, 158, 159, 
182, 187-89, 191, 192, 195, 
223, 230, 232, 233, 248, 249, 
266, 273, 276-78, 281, 283, 
284, 289. Lomont, H., 89. 
Longstaff, T. G., 62. Lop- 
penthin, B., 57, 59. Lorenz, 
K. Z., 166. Lucas, F. A., 76. 
Lumsden, W. H. R., 118, 
199. Lundevall, C.-F., 57. 
Manning, T. H., 139. Mar- 
chant, S., 59. Marples, A., 
86, 254, 256, 257, 260, 263, 

265, 266. Marples, G., 86, 
254, 256, 257, 260, 263, 265, 

266. Marshall, A. J., 123, 
124. Martin, M., 70, 93, 94, 
268. Mathieson, J., 96. 
Matthews, G. V. T., 159. 
Matthews, L. H., 188, 190. 
Mayaud, N., 28, 138. Mayr, 
E., 33, 37, 115, 116, 153. 
Meinertzhagen, R., 156. 
Mendall, H. L., 58. Miles, 
J. A. R., 114. Miller, A. H., 
59, 239. Miller, L., 59. 
Mohr, N., 73. Moller, 75. 
Monro, D., 69. Moreau, 
R. E., 246. Moseley, H. N., 
5. Mowbray, L. L., 78, 79. 
Mowbray, L. S., 58, 78, 79. 
Muller, H. C, 73. Murdoch, 



320 

J., 237. Murphy, R. C, 8, 9, 
29. 58, 77-79, 120, 123, 130, 
141, 143, 151, 168, 181, 216, 
221. Murray, G., 94, 96. 
MacAulay. K., 70, 71. Mac- 
Gillivray, J., 95. MacGil- 
livray, W., 235. M'Kenzie, 
Sir G., 69, 70, MacKenzie, 
N., 93-97. M'Kinnon, L., 
71. MacLeod of MacLeod, 
70. MacPherson, H. A., 93. 
MacQjueen, D., 71. 
Nansen, F., 235, 236. Nau- 
mann, J. F., 92. Newcomb, 
R. L., 235. Newton, A., 76, 
84, 268. Nichols, J. T., 78, 
187. Nicholson, E. M., 133. 
Noble, G. K., 231. Norton, 
A. H., 58, 59. 

Ober F. a. 77. Olafsson, 
E., 72, 73. Olavius, O., 72. 
Palmer, R. S., 59-61, 233, 
253-56, 265, 266. Paludan, 
K., 60, 229, 242, 244, 249, 
276, Parquin, Abbe, 138. 
Parry, W. E., 235. Pedersen, 
A., 63, 248. Pennant, T., 
149, Perry, R., 58, III, 211, 
226, 289. Peters, H. S., 58- 
60, 67. Petersen, P. F., 28. 
Peterson, R. T., 85, 104. 
Phelps, W.H., Jr., 162. Pitt, 
F., 123. Plath, K., 220. 
Portielje, A. F. J., 205. 
Preyer, W., 75. 
Raben, H. C., 74. Ramirez, 
D., 77. Rankin, M. N., 26, 
127, i35> i53» 266, 289. 



SEA-BIRDS 

Rasmussen, R. K., 114. 
Reeve, E. G. R., 48. Reid, 
S. G., 78. Richardson, J., 
235. Richdale, L. E., 182, 
189-92. Richter, R., 189. 
Riviere, B. B., 86. Roberts, 
B. B., 27, 168, 181, 182, 187, 
189, 190, 192. Roosevelt, T., 
85. Ross, J., 237. Ross, J. C, 
235. van Rossem, A. J., 59. 
Rothschild, W., 28. Rowan, 
M. K., 58, 163, 187, 189, 194, 
195. Rowan, W., 86, 123. 
Sabine, E,, 237. Salomonsen, 
F., 29, 43, 52, 54, 56, 58-61, 
63, 75, 100, 121, 139, 232, 
248, 253, 297. Sands, J., 95, 
96. Schoyen, C, 35. Schulz, 
H., 57, 59, 60, 91, 92. Scott, 
P., 83. Scott, W. E. D., 77. 
Seebohm, H., 140. Selous, 
E., 166, 205, 289. Sergeant, 
D. E., 59, 130, 134. Serventy, 
D. L., 28, 198. Shrivastav, 
J. B., 1 14. Shufeldt, R. W., 78. 
Sibbald, Sir R., 69. Snyder, 
J. P., 168. Sollas, W. J., 65. 
Soper, J. D., 42. Southern, 
H. N., 48-50, 52, 53. South- 
well, T., 215. Sprunt, A., 60, 
130. Stanford, W. P., 154. 
Steenstrup, J. J., 76. Steg- 
mann, B., 39. Steven, G. A., 
118, 198, 199. Stoker, 
M. G. P., 1 14. Storer, R. W., 
4. Stuart, Lord D., 213. 
Stubbs, F. J., 28. Surrey- 
Dane, D., 83, 114, 249. 



Svabo, J. K., 71. Swainson, 
W., 235. 

Taning, a. v., 156. Taver- 
ner, P. A., 42, 198. Temple- 
man, W., 52. du Tertre, 
J. B., 76. Thompson, B. H., 58, 
Thomson, Sir A. L., 138. 
Thorpe, W. H., 115. Tin- 
bergen, N., 175, 229, 230, 
245, 254, 255, 263. Towns- 
end, C. W., 286. Tuck, L., 
47. Turner, E. L., 212. 
Turner, L. McS., 286, 287. 
Uhler, F. M., 199. Ulfsson, 

G., 75- 

Valeur, p., 58. Verheyen, 
R., 57-59. Vesey-Fitzgerald, 
D., 60. Vevers, H. G., 57, 
58, 79-81, 99. Vicary, W. P., 
28. Vogt, W., 130. Voous, 
K. H., 141, 151. 
Waterston, G., 28, 57. 
Watson, J. B., 158, 254, 262. 
Wegener, A., 31. Wetmore, 
A., 10, 31, 32, 151. Wigles- 
worth,J., 96. Wilkins, G. H., 
195, 262. Williams, L., 205. 
WilUamson, K., 28, 58, 66, 
7i» 72, 99» ^00, 223, 225, 
226. Winn, H. E., 273, 278, 
281, 282, 286, 289. Winnall, 
R. N., 26. WoUey, J., 72, 76, 
307. Worm, O., 71. Wright, 
H. W., 197. Wurm, M., 
231. Wynne-Edwards, V. G., 
26, 58, 126, i3i-33> 135, 
153, 157.