Bulletin

HARVARD UNIVERSITY

ESL
LAS

LIBRARY

OF THE

Museum of Comparative Zoology

a

THE PEABODY MUSEUM OF NATURAL HISTORY
BULLETIN 3

HYBRID DUCKS, INCLUDING
DESCRIPTIONS OF TWO CROSSES OF
BUCEPHALA AND LOPHODYTES

BY
STANLEY C. BALL

us. COMP. ZESL
LIBRARY

HARVARD
GHIVERSITY

’ VERITAS

_NEW HAVEN

THE PEABODY MUSEUM OF NATURAL HISTORY

YALE UNIVERSITY
1934

PEABODY MUSEUM OF NATURAL HISTORY

TRUSTEES
James Rowianp ANGELL, Pu.D., Litt.D., LL.D.
His Exce,iteNcy THE GovERNOR oF CONNECTICUT, ex-officio.
Rey. Witi1aAm Apams Brown, Pu.D., D.D.
Howe ti Cueney, M.A.
Vance CrisweELL McCormick, M.A.
Frep Towstry Murpuy, M.D., M.A.
SamvueEt Hersert Fisuer, LL.D.

DIRECTOR
Ricuarp Swann Lutu, Pu.D., Sc.D.

CURATORS
Epwarp Sauissury Dana, Pu.D., Curator of Mineralogy, Emeritus.
Grorce Grant MacCorpy, Pu.D., Curator of Anthropology, Emeritus.
Cuaries Scuucuert, LL.D., Sc.D., Curator of Invertebrate Paleon-
tology, Emeritus.

Sraniey CrirTENDEN Batt, Pu.D., Curator of Zoology.

Cart Owen Dunsar, Pu.D., Curator of Invertebrate Paleontology.

Wituiam Esenezer Forp, Pu.D., Curator of Mineralogy.

Ricuarp Swann Lu tu, Pu.D., Sc.D., Honorary Curator of Vertebrate
Paleontology.

Corne.ius Berrien Oseoop, Pu.D., Curator of Anthropology.

Ausert Exper Parr, M.A., Curator of the Bingham Oceanographic
Collection, and Scientific Director of the Yale Oceanographic
Expeditions.

Epwarp Sapir, Pu.D., Sc.D., Honorary Curator of Anthropology.

Matcoitm Ruruerrorp THorpr, Pu.D., Curator of Vertebrate Paleon-
tology.

RESEARCH ASSOCIATES

Grorce Grant MacCurpy, Pu.D., Research Associate in Prehistoric
Archeology, Emeritus.

Hetimvut pe Terra, Pu.D., Research Associate in Geology.

Matcotm Ruruerrorp TuorpPr, Pu.D., Research Associate in Verte-
brate Paleontology.

Cuartes Epwin Weaver, Pu.D., Research Associate in Invertebrate
Paleontology.

RESEARCH ASSISTANTS

James Brooxs Knieut, Pu.D., Research Assistant in Invertebrate
Paleontology.

Crara Mar LeVene, B.A.

Nextpa Emetyn Wrieut, M.A.

ADVISOR IN GEOLOGY
Cuester Ray Lonewe x, Pu.D.

DOCENTS
Mixprep Cynruia Bevurtan Porrer, M.A., in charge.
Dorotuy Emma Arnoxp, B.A.
GertrubvE Horcuxiss CiarK.

Oe
i Vom
OY

iy

Hest
Sayin

THE PEABODY MUSEUM OF NATURAL HISTORY
BULLETIN 3

HYBRID DUCKS, INCLUDING
DESCRIPTIONS OF TWO CROSSES OF
BUCEPHALA AND LOPHODYTES

BY
STANLEY C. BALL

NEW HAVEN
THE PEABODY MUSEUM OF NATURAL HISTORY

YALE UNIVERSITY
1934

MUS. COMP. iss.
LIBRARY

HARVARD
UMEVERSITY

HYBRID DUCKS, INCLUDING
DESCRIPTIONS OF TWO CROSSES OF
BUCEPHALA AND LOPHODYTES

By Sranztey C. Baty

ANY hybrid ducks have been recorded, but as pointed out
by Bigelow (1907, p. 382), few specimens have been fully
described. Suchetet in 1896 published a summary of all descrip-

tions of hybrid birds then in print.

Since Bigelow’s 1907 paper numerous additional instances have
been recorded. Reviewing the literature, we find crosses between
many species. A suggestive list of these follows, the nomen-

clature being that of Peters’ Check-list (1931).

aie py arainteyn (ees Cte) xX Anas rubripes (Black duck). .

X Anas fulvigula fulvigula (Florida
ugk). erahtaiseie aaa! eset oie «
4 ‘ < Anas acuta ‘(Pintail)).. 0.6.25.
X Mareca americana (Baldpate)..
‘i Fi i x Spatula clypeata (Shoveller)...
cf i i xX Netta rufina (Red-crested duck)
X Anas superciliosa (Gray duck)..
“t i Fa udnaserecca (Mealy « sods) othe ia «
X Mareca penelope (Widgeon)....
Md % * X Chaulelasmus streperus (Gadwall)
X Catrina moschata (Muscovy) ...
is i ‘i xX Somateria molissima borealis
(Northern cider) 24552
iM A ie X Nyroca ferina (Pochard)......
; x Mergus merganser (Goosander)
Anas obscura (Dusky) X Anas undulata (of South Africa)......
anas acuity (Pintail) < Anas erecem:) (Meal) ints osyeca.} «chee, sis
i ts - 3 Spatula, elypeata. (Shoveller).....:....:.
X Anas querquedula (Garganey) ..........
Branta leucopsis (Barnacle goose) Anser fabalis (Bean goose)

Cairina mpechate (Muscovy) X Tadorna tadorna (Shield-drake). .
cs x Alopoctien aegyptiaca (Egyptian
PROOSE A) ho uhs S Urge rapping oes 28)!

ce ce ce

4 PEABODY MUSEUM OF NATURAL HISTORY

Cairina ate (Muscovy) X Anser anser (Gray-lag).........
ms 5 X Spatula clypeata (Shoveller)....

Aix sponsa (Wood duck) X 10 other species

Dendronessa galericulata (Mandarin) X 2 other species

Mareca penelope (Widgeon) X 6 other species (7 cases)

Anas crecca (Teal) X 38 other species

ay grace hee (Pochard) X Aix sponsa (Wood duck)...........
if xX N. africana (White-eyed duck)......
x = a XN. fuligula) (Tufted duck)... epee
ie fa 3 xX Anas rubripes (Black duck)........
* ry ss others

Nyroca marila (Greater scaup) N. africana (White-eyed duck)
Nyroca fuligula (Tufted duck) X 3 other species
Nyroca collaris (Ring-neck) X N. americana (Redhead)........
Melanitta fusca (Velvet scoter) X M. perspicillata (Surf scoter)
Bucephala clangula clangula (Golden-eye) X Mergellus albellus
(Siew ) 25% 0% yo eet ae Ws Sis ee eel ove as etel owl cee er
1. Mergus anatarius Eimbeck, 6, 1825, “Oker River, near
Brunsink.”
2. Clangula angustirostris Brehm, 2 , 1829, Germany.
3. Clangula mergoides Kjarbéling, 6, immature. In col-
lection purchased in Copenhaven, 1853.
4. February 1865, near Pol.
5. Nov. 20, 1881, at Kalmarsund. Skin at University of
Upsala in 1896.
B. clangula clangula 9 X.Mergus merganser $ .......2.-0em
Seen mating at Negelin, Oldenbourg. The male was shot.

B. BY clangula * Nyroca ferima (Pochard).....:...2. oem
B. > XN. marila (Greater scaup) “.:.5 1 -eeee
B. rr ‘a X Melanitia fusca (Velvet scoter).........

Bucephala clangula americana (American golden-eye) X Lopho-
dytes cucullatus (Hooded meéerganser)) ©... 2 -).'. ss 51-1 tenes
1. Clangula mergiformis Cabot, 6, Maine, 1854,
2. New Haven, ¢, 1920. Described in this paper.

At least 63 species (more than 94 instances) have mated with
species not their own. Anas platyrhynchos leads (14 species and
30 matings); others worthy of note are Nyroca ferina (8 and

20); Aix sponsa (10 and 10) ; Catrina moschata (4 and 10).

HYBRIDS OF THE GOLDEN-EYE (Bucephala clangula
clangula) AND THE SMEW (Mergellus albellus)

F special interest in connection with this paper are the
O hybrids of the European golden-eye (B. clangula clangula)
and the smew (Mergellus albellus) listed above, two of which may
now be considered in some detail.

Number 1. This hybrid is described by Eimbeck (in Suchetet)
as like the male Bucephala c. clangula in size, and in form of body
and tail; more like Mergellus in its long nape plumes, beak and
pointed wings.

From its extremity to the corner of the gape the beak is 46.5
mm.; base higher than wide; distal part flat, wider than high.
Seen from the side it resembles beak of merganser, but the serra-
tions are less visible. The statement that the form is especially
striking when seen from above may imply that the beak is narrow
and parallel-sided as in the merganser.

In color and pattern this bird stands intermediate between the
two parent species. Foundation white; head and neck deep
iridescent green; white spot between beak and eye; back brilliant
black, with some scapulars white; breast feathers mostly bordered
with black, having as marks traces of the two black collar-bands
so conspicuous in Mergellus, large wing feathers pure white (from
which statement we may infer that at least a part of the coverts
are black); feet not quite so large as in Bucephala but of same
form; deep rusty, web nearly black. Brilliant, well-colored
plumage stamps this bird as a male in prime plumage.

Number 3. Kjarboling (in Suchetet) first regarded this as a
young ¢ M., albellus, but later saw its relationship to Bucephala.
In general color he found it similar to Eimbeck’s male described
above, but juvenile feathers were particularly evident on the head.

The hybrid Anas platyrhynchos X Mergus merganser is inter-
esting for comparison with those previously described. Accord-
ing to Schliiter’s description (1891) it shows strongly the char-
acters of a domestic mallard drake, thus implying that it is a

6 PEABODY MUSEUM OF NATURAL HISTORY

male. In size, however, it approaches the larger Mergus mer-
ganser, on which account Schliiter assumed this species rather
than M. serrator to have been the mother.

In form the beak resembles that of A. platyrhynchos, but is
somewhat larger and wider. The nail, a somewhat interrupted
zone on the upper surface, and the base as well, are horn-colored ;
the rest yellowish brown. Head and adjacent neck feathers gray.
A few cheek feathers end in a faint greenish gloss as in the
domestic drake, while some neck feathers show a rusty red color
on their edges, inherited from the red-headed merganser. ‘Throat
yellowish-white although not so extensively as in the female
Mergus. Lower neck shows wide band of white, broken on hind
neck by dark gray feathers like those of head. The breast has,
although weakly indicated, the brown feathers of the mallard,
shot through with gray, and grades into color of belly whose
feathers have grayish-white bases and borders, speckled as in
A. platyrhynchos. Lower tail coverts similar, partly bordered
distally with black.

Back and upper tail coverts show mixture of spotted belly
feathers from the A. platyrhynchos ¢, and blue-gray back
feathers of M. merganser 2. Upper tail coverts also have black
terminal borders. Middle tail coverts blue-gray; the outer ones
shorter with white outer edges. Wholly wanting is the tendency
of the central coverts to curl upward as in the male mallard.

Primaries as well as under wing coverts are white; the specu-
lum blue-gray. Blue-green upper wing coverts edged with reddish
brown.

Feet stronger than mallard’s, but similar.

HYBRIDS OF THE MERGANSER (Lophodytes cucullatus)
AND THE GOLDEN-EYE (Bucephala clangula americana)

(Pl. I, Fig. 2; Pl. III, Fig. 17)

N December 20, 1920, while duck hunting near the break-
water at the mouth of New Haven harbor, Mr. L. Genung
shot a handsome hybrid duck which is now in the collections of
the Peabody Museum of Natural History at Yale (Cat. No.
4745). The shallowness of bill and number of tail feathers (18)
at once suggest merganser affinities, while the width and lamella-
tion of bill and color pattern point to one of the ducks as the
other parent.

On account of the small number of North American Merginae
it is expedient to determine first to which of these this bird is
related. The key to this part of the riddle is the two pairs of
black bands which extend from the back half way down the sides
of the breast. Only the hooded merganser (Lophodytes cucul-
latus) has these. Further comparison brings out the following
positive characters resembling this species: size small; sides of
breast and flanks tinged with cinnamon; small amount of white
on the scapulars; tertials black, four of them each with a narrow
white central stripe; shape of crest; black of upper neck joined
to that of the back by a broad dorsal stripe along the back of
the neck.

The American merganser (Mergus americanus) could have
contributed neither the breast bands nor the vermiculations on
the sides and flanks. Furthermore, it has a complete ring of
white about the lower neck (true also of Bucephala), a light gray
rump and tail, and a longer bill whose sides are orange-red.
This merganser lacks a crest and is relatively a larger bird
(635-685 mm.).

That the red-breasted merganser (M. serrator) is not con-
cerned in this hybrid is concluded from the following considera-
tions. The hybrid lacks the black-flecked reddish breast, and
the row of peculiar black-bordered white feathers on the side of

8 PEABODY MUSEUM OF NATURAL HISTORY

the upper breast in front of the wing; its posterior scapulars
have much less white, and the bill lacks the orange, and the back
and tail the gray color which characterize M. serrator; no evi-
dence of the elongated two-pointed crest exists; the black on the
neck all round extends farther posteriorly on the hybrid, and the
black band along the back of neck is broader. Again, the red-
breasted merganser is a larger bird (508-635 mm.).

Both positive and negative evidence, then, point to Lophodytes
cucullatus as one of the parents. As to the other parent, there
can be no doubt that it was either the American golden-eye
(Bucephala clangula americana) or Barrow’s golden-eye (B.
islandica); all other ducks are excluded by their size or color
pattern, or both.

Two characters of the hybrid favor B. clangula americana.
First, the iridescence of the head and neck is distinctly green
rather than purple and violet. Secondly, the single black wing
bar across the bases of the greater coverts is so narrow as to
suggest that, with L. cucullatus having two distinct bars across
the white wing patch, the other parent must have had less of a
bar than does B. islandica; B. c. americana has none. The dif-
ferences between the bills of the two species of Bucephala are not
sufficiently great to be helpful in determining which had crossed
with such a long, shallow-billed bird as a merganser.

Having settled upon Lophodytes cucullatus and Bucephala
clangula americana as the parents of this hybrid, one sees that it
stands as an extraordinary intermediate between the two species.

HYBRID DUCKS

TABLE I

COMPARISON OF NEW HAVEN HYBRID WITH ADULT MALES OF
LOPHODYTES AND BUCEPHALA

Lophodytes cucullatus

Length, 439-502 mm.
Wing

(folded), 191-201
Tail, length, 80-105

“number of
feathers, 18
Bill*
Culmen, loral
line to tip,

Height from
frontal angle to
lower edge of

40-42 mm.

upper mandible, 9.5
Least height (10

mm.fromtip), 4.5
Width at base, 12.5
Width (10 mm.

from tip), Uy

Width of scale, 6.1

From each edge of up-
per mandible project a-
bout 24 lamellae or ser-
rations, of which the most
posterior point somewhat
backward, their outer
faces slanting obliquely
inward and forward. On
the more anterior teeth
successively, these outer
faces slant inward less
and less until in the ter-
minal teeth they parallel
edge of mandible. (Figs.
7, 10.)

Form or MAte

Hybrid No. 4745

445 mm. (as mounted )

213
103

18

43 mm.

14.5
Height 10 mm. from
tip, 6

17

12.7
6.9

About 32 small serra-
tions along each edge of
upper mandible are al-
most concealed from lat-
eral view. As in LD. cucul-
latus, the more posterior
teeth extend obliquely in-
ward and forward, while
the anterior lie nearly
parallel with the edge.
These teeth are the ends
of lamellae which curve
obliquely upward and for-
ward on inner surface of
bill. (Figs. 8, 11.)

Bucephala clangula
americana

535-586 mm.

230-238
90-119

16

41-45 mm.

22.5-24.5
Least height (10 mm. from
tip), 7.5-9.5

19-22

18-19
6-6.5

About 33 lamellae ex-
tend from each edge of
upper mandible directly
upward on inner surface
of bill. Tips of a few
posterior lamellae are
barely visible below edge
of mandible in the dried
skin. (Figs. 9, 12.)

*It may be noted from the measurements above that the beak of Lophodytes
tapers considerably in width, while that of Bucephala has nearly parallel sides.
The New Haven hybrid favors the merganser in this character, while the Boston
Society bird approaches the golden-eye.

10 PEABODY MUSEUM OF NATURAL HISTORY

Lophodytes cucullatus

Lower mandible has
along its upper edges
corresponding serrations
which slant inward and
backward. ‘The anterior-
most of these unite to
form a continuous knife-
like edge. (Fig. 7.) No
series of ridges extend-
ing on outer aspect of
lower mandible.

Both upper and lower
teeth remain visible when
dried bill is closed.

Tarsus, 29-31 mm.
Middle toe and
nail, 52

Number of scales
on top of outer
toe, 44-46

Scales in the row along
front of tarsus (overly-
ing 3rd metatarsal) all
similar; central ones not
distinctly wider than
those below. (Fig. 13.)

Has distinct crest, lat-
erally compressed; long-
est nape feathers, 48 mm.

Head, entire neck,
black. Broad white patch
extends from back of eye

Hybrid No. 4745

Lower mandible has on
each upper edge 40 small
serrations, or lamellae, of
which the anterior extend
backward and inward, and
the posterior directly in-
ward. Anterior teeth not
united as in L. cucullatus.

A series of 46 short ex-
ternal lamellae along the
superior-lateral face of
the lower mandible, each
tooth extending obliquely
downward and backward,
as in Bucephala. (Figs.
He GIB)

Closure of bill hides all
these teeth and lamellae.

31

61

44-47

Sealation of left leg
as in L. cucullatus; of
right leg as in Buceph-
ala, (Figs. 14, 15.)

Crest fairly developed;
longest nape _ feathers,
33 mm.

Cotor oF Mate

Entire head (including
crest) and neck black,
not extending so far pos-

Bucephala clangula
americana

On each upper edge of
lower mandible is a series
of 51 serrations or lamel-
lae, of which the poste-
rior extend directly in-
ward and the anterior
obliquely backward and
inward.

A series of 46 well
developed lamellae along
each side of bill as in
most ducks; each ridge
extends obliquely down-
ward and_ backward.
(Figs. 9, 12.)

Closure of bill hides all
these ridges.

38-41

68

54-56

Middle scales in the
row on front of tarsus
distinctly wider than the
ones below, thus reduc-
ing abruptly the width of
the outer row of scales
(overlying 3rd metatar-
sal). (Fig. 16.)

No distinct crest; long-
est nape feathers, 23 mm.

Head and upper neck
black, with strong green
iridescence; large round-

Lophodytes cucullatus

upward and_ backward
covering most of the
crest; edge of latter
black. Sides of head and
neck with faint greenish
iridescence.

Back seal brown.

The black of neck joins
brown of back broadly.

Breast and belly white.

Two black crescentic
bars extend from upper
back before wing down
sides of white breast.

Fore wing, i.e., middle
and lesser coverts, gray.

In folded wing, white
patch on outer edges of
secondaries and greater
wing coverts is crossed
by a distinct bar of black
5 mm. wide (the black
bases of secondaries not
being covered by greater
coverts).

A second black bar
(exposed bases of greater
coverts) divides the white
wing patch from gray of
fore wing (middle and
lesser coverts).

HYBRID DUCKS

Hybrid No. 4745

teriorly on ventral sur-
face as in L. cucullatus.
Sides of head and neck
with moderate greenish
iridescence.

Back dark seal brown,
washed with black.

The black of neck joins
black of back broadly.

Breast and belly white.

Two black bars extend
from upper back down
sides of breast; bars nar-
rower and shorter than
in L. cucullatus.

Fore wing dark mouse-
gray, some feathers on
left wing fading to white
at tips.

White wing patch more
extensive than in ZL. cu-
cullatus, covering the
outer secondaries, greater
and middle coverts and
much of the lesser cov-
erts (to within 22 mm.
of front edge of wing).

Black on bases of sec-
ondaries so much covered
by white ends of greater
coverts, that no distinct
bar in this position is
evident.

Anterior black wing
bar present as in JL.
cucullatus.

Gh

Bucephala clangula
americana

ed white spot between
gape of bill and eye.

Back black.

Lower neck white all
around, continuous with
white of underparts.

Breast, belly, crissum
and under tail coverts
white.

No black bars on sides
of breast.

Front edge and bend
of wings black (30 mm.
wide).

In folded wing the
white patch is very large
and lacks the black cross
bar because bases of
greater secondaries are
less extensively black
and hence covered by
white ends of greater
coverts.

No black bar on great-
er coverts; their black
bases are covered by
white middle coverts.

12 PEABODY MUSEUM OF NATURAL HISTORY

Lophodytes cucullatus

Inner vanes of secon-
daries and all of tertials
black, the outer 5 tertials
with a narrow median
stripe of white (about
3 mm. wide).

Scapulars black.

Primaries seal brown.

Tail seal brown.

Sides and flanks red-
dish brown, cross-waved
and barred with black,
finely in front, coarsely
behind.

Sides of belly drab-
brown slightly barred
with whitish. Belly pos-
teriorly with brownish
tips.

Under tail coverts drab-

brown, speckled and
barred with white.

Bill black.

Iris yellow.

Legs and feet light

yellowish brown.

Hybrid No. 4745

Six outer secondaries
white over entire outer
vane; in some the inner
vanes are partly white.
Inner secondaries and all
the tertials black; 4 out-
er tertials each with nar-
row white median stripe
as in L. cucullatus.

Scapulars black, the
outer ones with broad
white central stripe as
in B. clangula americana,

Primaries seal brown
to black.

Tail seal brown washed
with ash.

Sides and flanks pale
cinereous vermiculated
with black, finely in front,
coarsely behind. Some
flank feathers washed
with cinnamon.

Sides of belly dark
brown, the ends of some
feathers edged with whit-
ish. A dusky bar sepa-
rates white of belly from
white crissum.

Under tail coverts
whitish, distally washed
and barred with drab-
brown.

Bill black.
Iris golden yellow
(glass eye).

Legs and toes appar-
ently yellow; webs dark
brown.

Bucephala clangula
americana

Eight outer secondaries
entirely white.

Inner secondaries en-
tirely black. Tertials
dark brown.

Outer scapulars white
with black edges.
Inner scapulars black.

Primaries seal brown.

Tail seal brown with
much ash.

Sides of breast and
flanks white, the upper
flank feathers sharply
edged with black.

Sides of belly drab-
brown; tips washed with

white. Crissum white.
Under tail coverts
white.
Bill black.

Iris golden yellow.

Legs and feet orange
or yellowish with dusky
webs.

HYBRID DUCKS 13

Reference to the tabular descriptions and to the illustrations
shows that the hybrid strikes nearly an average (blending)
between the parents in the following nine characters:

Length of wing

Length of tail

Size and shape of bill

Serrations or lamellae of bill

Length of crest feathers

Size of feet

Extent of white on outer secondaries

Degree of green iridescence on head and neck
Color of fore-wing.

In eleven other characters the hybrid presents a mosaic, resem-
bling L. cucullatus in:

Total length

Number of tail feathers

Length of tarsus

Number of scales on top of outer toe

Shape of crest

Extent of black on neck

Black stripe on back of neck

Presence of black breast bars

Black wing bar on bases of greater coverts

Narrow white stripes on inner secondaries and tertials

Sides and flanks vermiculated with black and washed with
cinnamon.

Characters of the hybrid which approximate those in B.
clangula americana are:
Solid black color of head and neck
Extent of white on wing coverts and outer secondaries
Broad white stripes on outer scapulars
Wash of ash on tail.

Perhaps as remarkable as any character in its distribution is
the scalation of the legs. On the left tarsus the shape and
arrangement of scales in the anterior rows closely follows that
of the merganser, while the right reproduces that of the golden-
eye (Figs. 13-16).

14 PEABODY MUSEUM OF NATURAL HISTORY

In these tabulations of the characters of the hybrid drawn from
its mismated parents it is to be noted that no cephalic white spots
enter. Both the loral patch of Bucephala and the white crest
area of Lophodytes have been suppressed. This fact might be
used as an argument in favor of assuming as the merganser par-
ent Mergus americanus, which lacks white on the head and has a
higher degree of greenish iridescence than does Lophodytes. But
these considerations are outweighed by others already emphasized.

Many interspecific and intergeneric crosses are known among
ducks, but this specimen seems to be the second recorded hybrid
between members of the North American subfamilies of the
Anatidae. Certainly the mergansers and golden-eyes are more
unlike physically than are the mallard (Anas platyrhynchos)
and the baldpate (Mareca americana) of which a hybrid is
described by Elliot (1892, p. 165).

Propinquity during the breeding season would be more proba-
ble in the western parts of the continent, although not impossible
in the east. Bent (1923, p. 13) gives the breeding range of
Bucephala clangula americana as follows:

Mainly north of the United States, entirely across the continent.
South to Newfoundland (Humber and Sandy Rivers), northern New
Brunswick (Northumberland County), central Maine (Washington to
Oxford Counties), New Hampshire (Umbagog Lake and Jefferson
region), northern Vermont (St. Johnsbury), northern New York
(Adirondacks), northern Michigan (Neebish Island, Sault Ste. Marie),
northern Minnesota (Lake County), northern North Dakota (Devils
Lake), northwestern Montana (Flathead Lake and Glacier National
Park), and the interior of British Columbia.

North to the limits of heavy timber in central Alaska, southern
Mackenzie, the southwest coast of Hudson Bay, and the northeast
coast of Labrador. Replaced in northern Europe and Asia by a
closely allied race.

The breeding range of Lophodytes cucullatus, according to
Forbush (1925, p. 188), is:

Locally in wooded regions from southeastern Alaska, central Brit-
ish Columbia, Great Slave Lake, northern Manitoba, Ontario and New

PLATE I
Fig. 1. Hooded merganser (Lophodytes cucullatus).

Fig. 2. Hybrid (L. cucullatus x Bucephala clangula americana), Cat. No.
4745, Peabody Museum.

Fig. 3. American golden-eye (Bucephala clangula americana).
Figs. 4, 5 and 6 are dorsal views of the beaks of these respective birds.

Figs. 1-3, « 1%. Figs. 4-6, x 1.

PLATE II

Figs. 7, 8 and 9, beaks of L. cucullatus, the hybrid, and B. c. americana.

od

Fig. 10. Enlargement of the part of beak between lines x—y in Fig. 7.
a, lamellae on left-hand edge of upper mandible; d, inner surfaces of lamellae
on right-hand edge; b, lamellae of lower mandible.

Fig. 11. Similar enlargement of part of Fig. 8. Note c, the short lateral
lamellae.

Fig. 12. Same for Fig. 9. Note the great lateral lamellae, c.

Figs. 13 and 14. External views of left tarsi of L. cucullatus and hybrid,
showing similar arrangement of scales in the two large anterior rows.

Fig. 15. External view of right leg of hybrid, showing second row of scales
interrupted by wide central scale, a, of first row.

Fig. 16. Normal scalation of B. c. americana, left leg, with the same
arrangement as in Fig. 15.

Figs. 7-9, & 114. Figs. 12-16, « 1.

PLATE III

Fig. 17. Hybrid (L. cucullatus x Bucephala clangula americana). In
Beston Society of Natural History; Cat. No. 17972. x 14.
Fig. 18. Beak of same, enlarged to show the serrations and lamellae.
73:
Fig. 19. Hybrid (Anas platyrhynchos x Anas rubripes). In Peabody
Museum, Yale University; Cat. No. 11035. x Y.
a. Right side, showing white wing bars.
b. Left side, showing general pattern.

PLATE I

II

PLATE

ene

Wy.
AAA

aN . te i - ” = IE, aS
, sy NY SN wot . i all ene ee ——

RAR

PLATE III

HYBRID DUCKS 15

Brunswick (probably in central Ungava (northern Quebec), southern
Labrador and Newfoundland) south to Oregon, northwestern Nevada,
northern New Mexico, southern Louisiana, southern Tennessee, Ala-
bama and central Florida.

The overlapping winter ranges of the two species concerned
would have permitted the mating of this hybrid’s parents before
their northward migration, for Bent (1925, p. 13) sets the winter
range of the golden-eye thus:

Cold coasts and large lakes south of frozen areas. On the Atlantic
coast commonly from Maine to South Carolina; more rarely north to
the Gulf of St. Lawrence and Newfoundland and south to northern
Florida. Rarely to the Gulf coasts of Mississippi, Louisiana, and
Texas. On the Pacific coast from the Commander and Aleutian
Islands to southern California and casually to central western Mexico
(Mazatlan). On the Great Lakes (Michigan, Erie, and Ontario).
Irregularly north in the interior to southern British Columbia, north-
western Montana, and the valleys of the Missouri and Mississippi
Rivers, as far as Nebraska and Iowa; and south to Colorado and
Arkansas and occasionally to Arizona and Texas.

This region is overlapped by the winter range of Lophodytes,
given by Forbush (1925, p. 188) as:

Southern British Columbia, Utah, Colorado, Nebraska, Illinois,
Indiana, Pennsylvania and Massachusetts south to Lower California,
southern Mexico, the Gulf states and Cuba; uncommon to rare in

northeastern part of range. Recorded from St. Michael, Alaska, also
Ireland, Wales and Bermuda.

Since the hooded merganser is seldom seen on salt water, the
liaison, if it were contracted south of the breeding grounds,
probably took place on some of our inland streams or ponds.

As to nesting habits, it is interesting to note that both
Lophodytes and Bucephala are tree dwellers. Therefore the site
selected by his mate was doubtless approved by the male, whether
he were merganser or golden-eye.

While it would be idle to speculate concerning the sex of the
two species involved, since this male hybrid could as well have
inherited his characters from either male or female parent of

16 PEABODY MUSEUM OF NATURAL HISTORY

either species, one may be allowed to imagine that the male parent
was Bucephala, for it is well known that the male golden-eye,
even among amorous ducks, is an especially ardent wooer
(Brewster, 1911). One may also infer that this hybrid inherited
from its golden-eye parent at least a tolerance of salt water.

A search of the literature has revealed but one other recorded
hybrid between Lophodytes and Bucephala. This interesting
example was presented to the Boston Society of Natural History
in May, 1854, by H. D. Morse, having been taken May 2 at
Scarborough, Maine, by Caleb Loring, Jr. Dr. Samuel Cabot
exhibited this bird (Cat. No. 17972) at the following June meet-
ing of the Society. His description, published in the Proceedings
of 1854-56, includes notes on both external and internal anatomy.

Cabot’s specimen is a male, apparently two years old, coming
into adult nuptial plumage.

A description of the successive Lophodytes plumages may be
found in A. C. Bent’s “Life Histories of North American Wild
Fowl” (1923, pp. 26, 27):

The downy young is thickly and warmly clothed with soft down in
deep, rich shades of “bister” or “sepia” above, including the upper
half of the head, the hind neck, and the flanks; the sides of the head,
neck, and cheeks, up to the eyes, are “buff pink” or “‘light vinaceous
cinnamon,” the chin, throat, and under parts are pure white; and
there is an obscure dusky band across the chest and an indistinct
white spot on each side of the scapular region and rump.

In the first plumage the sexes are alike and much resemble the adult
female, but they are browner on the back and have undeveloped crests.
Young males wear this immature plumage all through the first year,
with only a slight change toward maturity during the first spring and
the following summer. The summer molt leaves them still in imma-
ture plumage and with but little change in the new wings, which still
lack the pearl-gray lesser coverts and in which the greater coverts
are only slightly white-tipped. In November and December of this,
their second winter, they begin to assume a plumage resembling that
of the adult; the molt begins with the appearance of black feathers
and white feathers in the head, spreading downward to the breast,
flanks, and scapulars, until by March or April a nearly adult plumage

HYBRID DUCKS 17

is assumed. In this plumage the colors are all duller than in old
males; the crown, back, and rump are browner; the gray lesser wing-
coverts are acquired, but the wings are otherwise immature. A partial
eclipse plumage is assumed during the next summer, when the bird
is two years old and late in the fall, November or December, the fully
adult plumage is acquired. Young females can be distinguished from
adults during the first year by their undeveloped crests and their
duller and browner coloring everywhere; they become indistinguish-
able from the adults during the second winter.

Adult males have a semi-eclipse plumage in summer, in which the
head and neck become largely mottled with brownish and the breast
and flanks lose their brilliant colors and resemble those of the female.
The double molt is probably not complete, though the whole plumage
is changed at least once. The full plumage is assumed early in the
fall, much earlier than in young birds, and is usually complete in
October.

We may now return to Cabot’s hybrid. Taken in the second
spring, the feathers of its neck, head, and well-developed crest
are still largely in the immature brown stage, although many
black feathers have already appeared. These are especially
conspicuous on the neck, which is dark gray to the base as in
Lophodytes. Other immature characters are the sprinkling of
black tips on the white feathers of the basal ventral surface of
the neck and anterior breast, and the ashy edges of the dorsal
body feathers, intensified by wear.

This hybrid lacks the white stripes on inner secondaries and
tertials which are peculiar to the adult male Lophodytes, and
also lacks the white outer margins of the scapulars present in
Bucephala. Perhaps in time they would have developed. The
same possibility exists with regard to the very rudimentary black
bands extending ventrally in front of the wing on the sides of the
breast, the white wing patch, the tertial and scapular stripes.
Doubtless maturity would have sharpened the contrast between
dark neck and white breast feathers. As in the adult male
hooded merganser, but less intensively and over a smaller area,
the sides of the breast and flanks are washed with cinnamon and
vermiculated with black.

18 PEABODY MUSEUM OF NATURAL HISTORY

The outer secondary alone is bordered with white, but this is
sufficiently prominent to form as in Lophodytes the posterior
white bar, separated by the black basal bar across this secondary
from the anterior white wing bar across the ends of the greater
coverts. The middle and lesser coverts are white, irregularly
mottled and washed with gray.

The beak resembles that of the merganser more closely than
that of the golden-eye, thereby approaching the New Haven
hybrid in character, but unlike the latter, its beak, instead of
tapering, is parallel-sided as in clangula (Fig. 6). The serra-
tions and lateral lamellae, especially on the lower mandible, are
less well developed than in the New Haven bird, although closely
similar in form and arrangement. Both hybrids follow Lopho-
dytes in the shape and position of the nostrils.

Whereas the New Haven specimen in scalation of its tarsi
follows Lophodytes on one leg, and Bucephala on the other, the
Maine hybrid resembles the latter on both tarsi.

Compare with Table I, the following:

TABLE II

ANALYSIS OF IMMATURE MALE HYBRID, LOPHODYTES CUCUL-
LATUS x BUCEPHALA CLANGULA AMERICANA (BOSTON
SOCIETY OF NATURAL HISTORY, CAT. NO. 17972)

A. Exrernat Anatomy (Fics. 17, 18)

Weert, ie ais sore sts’ jo, Sais Mapa teual topes ane aoa eee 450 mm.
WY Brn * ie a sisi atusr ase taerniat at veus alleve: ot Ghavane a atte emonen 222
Tail, Ten geby sis 3s hides isis icys 6 ee as Bake iawn are ee 110
Number ‘of rectrices: .).).\0t ois <i «oie io ooh a 18
Bill
Culmen, loral line to tip...... ty anes te emit 41.5
Height, from lower edge of upper mandible to
frontal angle) j.(3:.3:35 avs. Pie; a ee 17
Least height’ (10 mm, from: tip)isa5.¢. sheer 6
Width. of base, is 3.5 belies eek Seon d oars 16
“1. Oka) froma Epis is daiehiiinateye einen ates 13

“e

of ‘seale fee ee eee 8

HYBRID DUCKS 19

About 26 serrations along each edge of upper mandible are almost
concealed from lateral view. They agree with those in the New
Haven hybrid in form and direction.

On each upper edge of the lower mandible are 45 serrations similar
in form and arrangement to those in the New Haven hybrid, but the
six anteriormost hardly rise above the surface.

A series of 39 short external lamellae occurs along the superior-
lateral face of lower mandible as in the New Haven hybrid. Closure
of bill hides all teeth and lamellae.

The upper mandible is almost parallel-sided, thus resembling
Bucephala more closely than does the New Haven hybrid.

OH RUG ects ea ketene) satay ais Wael s/feve\fe ep ev acetate” © a) eaiaes 34 mm.
Middle: toe; and) mails yo. 20.03) 6 ahs, s)sioaviess ere!ci says 62
Number of scales on top of outer toe......... 44

Scalation of both legs as in Bucephala (Fig. 16).
Crest well developed; longest feathers 38 mm.

B. Cotror

Second spring plumage, still immature; considerably worn.

Head and neck chestnut brown, with many newly formed black
feathers. Dark color does not descend downward so far on fore-neck
as in Lophodytes; meets white of breast in zone of immature spotted
feathers.

Back dark seal brown; feathers edged with grayish.

Dark color of neck and back broadly joined together.

Breast and belly white; two black bars on sides of breast slightly
developed.

Middle and lesser wing coverts white mottled with gray.

White wing-patch broken by two broad black bars across bases of
secondaries and greater coverts. Outermost secondary alone has white
band on outer vane.

Scapulars black; primaries seal brown; tail seal brown; sides and
flanks pale cinereous vermiculated with black as in the New Haven
hybrid; sides of belly and crissum dark drab brown; bill black; glass
eye golden yellow; legs and toes apparently yellow; webs darker.

Apparently the genes which are responsible for many visible
characters of L. cucullatus and B. clangula americana segregated

20 PEABODY MUSEUM OF NATURAL HISTORY

in true Mendelian fashion in the maturation of the gametes which
united to produce the New Haven hybrid. Many of these genes
were able to exert almost their full influence, resulting in a bird
which presents a remarkable mosaic of the two sets of parental
characters; for example, number of tail feathers, tarsal scala-
tion, marking of tertials and scapulars. On the other hand,
certain attributes appear as blends between homologous parental
structures, e.g., size of bird, color of head, form of bill. Other
features which are present in one parent and absent in the other,
such as the two black breast bars, crest, lateral lamellae on beak,
and vermiculations on flanks and sides, exist in the hybrid, but
have been modified somewhat in size, in form, or in both.

While the same remarks apply to the hybrid from Maine, the
characters are less well-defined owing to its immaturity.

A comparative analysis of the two hybrids is given in
Table III:

Some characters which at first glance suggest that blending
has occurred, upon analysis reveal the probability that they are
in reality to be regarded as mosaics. For example, the head is
entirely black in the New Haven hybrid, but incorporates the
black cheeks of Lophodytes and the black nape of Bucephala.
From another point of view, neither the white cheek patches of
the one nor the white crest patch of the other parent species were
able to develop. This may have been on account of a conflict
of genes.

When considering these matters, one should bear in mind the
evident immaturity of the Maine hybrid, and the remote possi-
bility that even the New Haven bird might in a following season
have developed more fully the pattern elements of one or both
parent species.

Table III may be summarized as follows:

No. of characters No. of blended No. of characters

favoring characters favoring
Lophodytes Bucephala
New Haven Hybrid... 614 3 71,

Mame Poy brid: 4). > 61% 3 5

21

HYBRID DUCKS

“ApLINnzeuUL Jo yUNOIIe uO ATqeqoig ,

x xX x esses gure
x x x x x ‘* UIABET MIN
pjpydaong ayy
S¢ ee eee eee suey
x ‘* UIABEY MINT
A9ATSUI]XI anymore
ssay ynq
x x x ERENT CY 1
QAISUQ}XO
ssay ynq
SK x *< x “* UdABFT MAN
sagipoydoT ayxvy
20} sti syuvy pue yoyed AviZ ssa] 10 $}19A09 s[B1}.194 SIP
a[pprun s Sa0I1}0a1 | saprs uo surm 210UI $}19 1ayea13 uo -ndvos
uvy} Ja3u0] einae udId}YSI SUuOT}P] ayYM JO | -Aod a_ppru uo 1eq sodriys uo
90} 19]NO noma A | uotsua}xq | pue Jassa’y yori ovTU MA a71UM.
SI LI 91 ST PI &1 al II or
x x< eee eens QUuIBvI,
>a x< << *' UdABFT MIN
pjoydeong axV]
OX SK a UuIvy
>< SK ‘* UdARAT MIN
eA surpuel_
x x -udulIpny IBIS e008) OUT RIAT
x x yysugy % asolO "+ UdABEY MAN
sajhpoydoy ayvy]
oe dou pue sie a] qIpueur
anamrot an do adevu yuasoid ‘aia tin jo eats. ue Apoq
yoou soUsdSeplat | yoelg ysa1Q yoryq a3 po uo ae] [PUP] pue u110j go
jo sov[g u2sa15 OM], SuOT}eIIIG [e19}e'T [e1guery oats
6 8 L 9 g ¥ & (4 I

Ill WIAVL

22 PEABODY MUSEUM OF NATURAL HISTORY

This summary reveals the consistency of inheritance in the
two birds. Maturity might have brought out in the Maine
hybrid one more character from Lophodytes (white tertial
stripes), and two more characters of Bucephala (white scapular
marks, green iridescence on head).

Of the 18 characters observed, 13 were similarly inherited by
both hybrids (1, 2, 5, 4, 5, 6; ‘7, 9, 12, 18, 15, 16, 18)charare
uncertain because of immaturity of the Maine bird (8, 10, 11);
one (17) follows Bucephala in the Maine hybrid, while in the
New Haven bird the character appears complete as in Lophodytes
on one leg, and as in Bucephala on the other leg; finally, a single
character (14), with due allowance for immaturity, is reversed
in the two hybrids.

One may now profitably compare with the Maine and New
Haven hybrids a few characters of Eimbeck’s European hybrid
Bucephala clangula clangula < Mergellus albellus described on
an earlier page. This bird was a fine male in full plumage.
One parent (Bucephala) was almost identical for all three birds.
The other parent (Lophodytes) was identical for both American
hybrids, but for the European was another species of black and
white merganser, the smew. This species (Mergellus albellus)
differs considerably from Lophodytes, especially in lack of crest,
but resembles it in possessing two black crescentic bands on each
side of the white breast, and two white wing bars.

Eimbeck’s hybrid inherited traces of the black breast bars of
Mergellus, the black head and green iridescence of Bucephala
(wing bars not mentioned). Absence of crest is consistent with
its absence in both parents.

The striking feature, as contrasted with the two American
specimens, is the presence of a “white spot between the beak and
eye.” In this respect the Bucephala pattern dominated.

Both Guyer (1909) and Phillips (1914) remark on the pre-
ponderance of males among hybrid ducks, especially in cases
where the parents are distantly related. It is interesting to note
that all hybrids discussed in this paper are males.

HYBRID MALLARD (Anas platyrhynchos) X BLACK
DUCK (Anas rubripes)

(Pl. III, Fig. 19)

HIS bird (Peabody Museum, Yale University, Cat. No.
A ious was taken with two wild red-legged black ducks at
Milford, Connecticut, November 11, 1932. It resembles A.
rubripes rubripes closely on head and neck. The upper and
under parts of the body are somewhat lighter and warmer in
color. Feathers of the breast and under tail coverts especially
are widely margined with vinaceous-cinnamon (IV/15). Many of
them have one or more additional interrupted bars of the same
color. This reddish tendency is doubtless inherited from the
mallard.

Even more mallard-like are the wings. Although in hue the
speculum is greenish-blue, as in the black duck, it is bordered by
the two white bars of the mallard, one crossing the greater
coverts below their black tips and the other whitening the ends of
the secondaries. The white under wing coverts show their
rubripes inheritance in the broken row of dark spots near the
edge of the wing. Like both mallard and black duck, this hybrid
has white axillars, but is exceptional in bearing one right axillar
with three broad, but incomplete bars and a terminal spot of gray.

When first seen the tarsi were lighter colored than in the black
duck, and less orange than in the mallard; according to Ridg-
way’s nomenclature (1896) the hue was two-thirds salmon (Plate
VII, No. 17) and one-third saturn red (VII, 16); feet some-
what more dilute. Tarsi of a black duck taken at the same time
were two-thirds salmon and one-third orange vermilion (VII, 12).

In form the only notable hybrid character is in the bill. This
is intermediate between the higher, wider, parallel-sided beak of
A. rubripes and that of A. platyrhynchos which is narrower at
the base and somewhat flatter anteriorly. When fresh the color
was chromium green (X, 12) warmed with olive-yellow (VI, 16)

24 PEABODY MUSEUM OF NATURAL HISTORY

toward the base, and fading through sage green (X, 15) to pea
green (X, 9) at the tip; darker along antero-lateral edge; nail
nearly black; upper surface of culmen dusky. The bill of
A. rubripes taken at the same time was nearly ochre yellow
(V, 9), with nail and margin darker; much darker on inside of
upper mandible and on teeth of lower mandible.

There can be no possibility that this bird is an immature male
mallard, for the head and neck are typically ashy as in the black
duck, not buffy. The tail feathers lack the white margins of the
mallard and are in prime condition instead of being ragged and
worn as is usually true of the immature mallard in November.
The breast is very much darker than that of a young mallard.

BIBLIOGRAPHY
Bent, A. C.

Life histories of North American wild fowl.
U. S. Nat. Mus. Bull. 126, 1923; Bull. 130, 1925.

Bicetow, H. B.
On hybrids between the mallard (Anas boschas) and certain other

ducks.
Auk, vol. 24, pp. 382-388, 1907.

Brewster, WILLIAM

Courtship of the American golden-eye or whistler.
The Condor, vol. 18, pp. 22-30, 1911.

CasotT, SAMUEL

Wild hybrid duck, Clangula americana and Mergus cucullatus.
Abstract, Proc. Boston Soc. Nat. Hist., vol. 5, pp. 118-120,
1854.

Exuior, D. G.
Hybridism, and a description of a hybrid between Anas boschas
and A. americana.
Auk, vol. 9, pp. 160-166, 1892.

Forsusn, E. H.
Birds of Massachusetts and other New England States, vol. 1, p.
188, 1925.
Guyer, M. F.
On the sex of hybrid birds.
Biol. Bull., vol. 16, pp. 193-198, 1909.
Prerers, J. L.

Check-list of the birds of the world.
Vol. 1, Harvard Univ. Press, 1981.

IPaILLIPs, J. C.

Size inheritance in ducks.
J. Exp. Zool., vol. 16, pp. 131-148, 1914.

26 PEABODY MUSEUM OF NATURAL HISTORY

Ripaway, Rosert
Nomenclature of colors for naturalists.
Boston, 1896.
ScHLuUrer, W. von
Hybrid Anas boscas X Mergus merganser.
Ornitholog. Jahrbuch. Bd. 1, Heft 1, pp. 109-110, 1891.
SucHETET, A.
Des hybrides 4 l’état sauvage. Classe des oiseaux.

Régne animal, vol. I, pp. 1002, Paris, 1897.

ZootoaicaL Recorp, 1900-1931.

=

Prd 4

\ " aa iy, ; st a,
As i a) ah A 1) , ay)
bee eh - J ani 7

OY tan i f
en ee ‘

1 7
BME itt
q
ny i i
ina 4) ;
yar)

if i

.
J

Additional Copies
of this Bulletin may be procured from
Peabody Museum of Natural History, Yale University,
New Haven, Conn.,
at
25 cents per copy.

a A ,

ais H

7 nN , be SA
is Th iP \

bb

th

—
a
i
\
{
i
é
J ‘
"

7 :

i

.

| LH is
ie
ry ie _ : ie .

7 ry oy) :
aid i" ie ri

} i

¢ wn see a

a

Harvard MCZ Libra

LOCO

Date Due

poe ser ae oT Oe a ee ee ee a a ee od
: -« oe
: * 7 a °
he ‘ a8 . tts :
ois . . Pe - -
: : $