840 
U. S P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
STERCORARIUS CEPPHUS, (Briinnich.) 
Bnffon’s Skua. 
Catliaracta cepphus, Brunn. Orn. Bor. 1764, 36. 
Lestris cepphus, Keys. & Blas. 1840.— Bon. Cons. Av. II, 1856, 209. 
Lestris bvffonii, Boie, Isis, 1822, 562.— Bonap. Synop. 1826, No. 306. 
Lestris parasitica, Rich. & Sw. F. B. A. II, 1831, 430.— Aud. Birds Amer. VII, 1844, 192 ; pi. ccccliii. 
Arctic Bird, Edwards, Birds, pi. cxlviii. 
Sp. Ch.— Adult. Space between the eye and bill, top of the head and nape black; cheeks and sides of the neck yellowish 
white ; back and wings blackish gray ; quills and tail black ; the shafts white, except near their tips ; under plumage white ; 
breast tinged with pale yellow ; flanks and lower tail coverts brownish gray ; bill dull flesh color, dark at the tip ; feet black ; 
tarsi yellow in front. The two middle tail feathers are six or eight inches longer than the others, and taper gradually to a fine 
point. Length, about 20 inches; wing, 12 ; tail, 10 to 12 ; bill, lj-L ; tarsi, 1 
Hab. —Arctic seacoasts of America; Baffin’s Bay. 
There are no specimens of any of the genus Stercorarius in the collection, hut in the private 
cabinet of Prof. Baird are specimens of the three last species. These he has kindly sent me 
for examination. They are the more interesting from the fact of being Mr. Audubon’s type 
specimens of the three species described by him, although in assigning names to two of them I 
have been compelled to differ from him. 
List of specimens. 
Catal. 
Sex and 
Locality. 
Whence obtained. 
No. 
age. 
2062 
Adult.. 
Boston__ 
S. F. Baird. 
Sub-Family LARINAE.—The Gulls. 
Ch.— Bill differing considerably in strength and form ; generally straight, with the sides compressed ; the culmen straight 
at the base, with the end curved ; t nostri!s lateral and oblong ; wings long and pointed ; tail usually even ; in two or three cases 
pointed or forked ; tarsi rather strong ; fore toes united by a web ; hind toe short and elevated. 
These birds vary much in size, some being quite small, while others rank among the largest 
of marine birds. They are not peculiar to any region, but are found abundantly over the 
world. They congregate in large numbers on the sand bars at the entrance of inlets and large 
bays. In winter they migrate in search of food, frequenting harbors and ascending rivers. 
This sub-family has been subdivided into many genera by different writers, in some cases 
the distinction being based mostly upon the color of the wings or back. Prince Bonaparte and 
M. Bruch, who have both specially, studied this family, differ very much in the generic 
arrangement. Gf. R. Gray, in his Genera of Birds, does not approve of so great a subdivision, 
and has retained most of the large species under the old genus Larus, which accords with my 
own views. 
