PELECANUS (CARBO) DILOPHUS, DOUBLE-CRESTED CORMORANT, Swains, and Richards.
Fauna-Bor. Amer. part ii. p. 473.
DOUBLE-CRESTED CORMORANT, Nuttail, Manual, vol. ii. p. 483.
Adult Male at the commencement of the breeding season. Plate
CCLVII.
Bill about the length of the head, rather slender, somewhat compressed,
straight, with the tip curved. Upper mandible with the dorsal line
slightly concave, until near the tip, when it is curved, the ridge convex,
and separated from the sides by a narrow groove, the sides erect, convex,
the edges sharp and straight as far as the unguis, which is strong, convex
above, incurved, acute. No external nostrils. Lower mandible with the
angle long and very narrow towards the end, filled by an extensive membrane,
which extends a short way down the throat, its dorsal line a little
convex, the sides erect and convex, the edges sharp and inflected, the tip
compressed and obliquely truncate.
Head rather small, oblong, narrowed before. Neck long and rather
slender. Body full, depressed. Feet short, stout, placed far behind;
tibia feathered in its whole length; tarsus very short, strong, much compressed,
covered all round with scales, of which the anterior and lateral
are large and subhexagonal, the posterior very small and roundish. Toes
all placed in the same plane, and connected by reticulated webs, covered
above with very numerous oblique scutella; first toe smallest, fourth
longest. Claws rather small, strong, compressed, acute.
Plumage of the head, neck, lower parts and posterior portion of the
back glossy, blended and silky, of the fore part of the back and wings
compact, the feathers with loose glossy* margins. From behind the eye
to the length of an inch and a half on each side, an elongated tuft of long
slender, loose recurved feathers. Space around the eye, and to a large
extent along the base of the bill, together with the small gular sac, bare.
Wings rather small; primaries very strong, curved, rather narrow, tapering
and obtuse, second longest, third almost equal, first longer than fourth;
secondaries decurved, broad, broadly rounded, the inner narrower. Tail
of moderate length, very narrow, much rounded or cuneate, of twelve narrow,
rounded feathers, having extremely strong shafts.
Upper mandible dusky, along the edges greyish-yellow; lower yellow,
irregularly marked with dusky towards the edges. Iris bright green,
margin of eyelids, bare space on the head, and gular sac, rich orange.
Feet and claws black. All the silky part of the plumage is greenishblack,
at a distance appearing black, but at hand in a strong light green.
The imbricated feathers of the back and wings greyish-brown, their
fringe-like margins greenish-black; primary quills brownish-black; secondary
like the* other feathers of the wing. Tail black, the shafts of all the
feathers black.
Length to end of tail 33 inches, to end of wings 29, to end of claws
33 ; extent of wings 51 ; wing from flexure 13 ; tail 6 | ; bill along the
back 2T
8
2 , along the edge of lower mandible 3T
8^ ; tarsus 2j\ ; outer toe
3f, its claw * j . Weight 5 lb. 7 oz.
The Female is somewhat smaller, but in other respects is similar to
the male.
The Young, after the first moult, have the head and neck mottled
with greenish-black and greyish-brown; the other parts as in the adult,
but the tufts on the head wanting.
The Double-crested and the Florida Cormorants are very nearly allied,
their forms, and the structure of their plumage, being precisely similar.
There is, however, a very considerable difference in size, as will be seen
on comparing their measurements and average weights as given by me.
The bills are similar in form, but their colours differ, as do those of the
eyelids ; but in the breeding season these birds may readily be distinguished
by the temporary tufts or crests behind the eyes, which in P.jloridanus
consist of a mere line of single feathers curved down wards, while in P. dilophus
they are of considerable breadth, and composed of about forty recurved
feathers. In the absence of the crests, the difference in size affords the
principal means of distinguishing them.