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U, S p. E. R. EXP. AND SURVEYS — ZOOLOGY — aENERAL REPORT. 



STERCORARIUS CEPPHUS, (Briinnich.) 

 Bnflbn's Skaa. 



Culharada cepphus, Brikn. Orn. Eor. 1764, 36. 



Lestris cepplms, Keys. & Blas. 1840.— Bov. Cons. Av. II, 1856, 209. 



Lestris buffonii, Boie, Isis, 1822, 562.— Bonap. Synop. 1826, No. 306. 



Lcslris parasitica, Rich. & Sw. F. B. A. II, 1831, 430.— Aud. Birds Amer. VII, 1844, 192 ; pi. ccccliii. 



Arctic Bird, Edwards, Birds, pi. c.xlviii. 



Sp. Ch. — ^dult. 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 coyerts 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°g ; tarsi, Ij^. 



Hab. — Arctic seacoasts of America ; Bafiin's Bay. 



There are no specimens of any of the genus Stercorariiis in the collection, but 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. 



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 ; ^nostrils 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. Brucli, who have both specially studied this family, differ very much in the generic 

 arrangement. G. 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. 



