BIRDS OF NORTH AND MIDDLE AMERICA. 597 



L[arus] nelsoni Ridgvvay, Man. N. Am. Birds, 1887, 27. 



[Lams] nelsoni Sharpe, Hand-list, i, 1899, 142. — Forbes and Robinson, Bull. 



Liverp. Mus., ii, no. 2, 1899, 58. 

 [?] Larus kumlieni (not of Brewster) Murdoch, Exped. Point Barrow, 1885, 123 



(Point Barrow, Alaska). 



LARUS GI/AUCESCENS Naumann. 



GLAUCOUS-WINGED GULL. 



Adults in summer (sexes alike). — Head, neck, rump, upper tail- 

 coverts, tail and entire under parts, including axillars and under 

 wing-coverts, immaculate pure white; back, scapulars, and wings 

 uniform pale neutral gray (deeper than in I^. leucopterus), the second- 

 aries extensively and rather abruptly white distally, the primaries 

 becoming darker (the fourth and fifth, from outside, abruptly so) 

 subterminally, and abruptly tipped with white; outermost primary 

 with an additional white space immediately anterior to a sub- 

 terminal spot 25 mm. or more long of deep gray, the second (from 

 outside) gray to extreme tip or else with a very small white tip, and 

 small white spaces at some distance from tip on one or both webs; 

 sixth primary (from outside) with a broad subterminal bar or band 

 of deep gray, preceded by a white area; bill yellow, whitish at tip, 

 the mandible with a subterminal lateral spot of red; rictus flesh 

 color; iris light yellowish gray or dull creamy white; naked orbital 

 ring reddish flesh color (in life); legs and feet flesh color. 



Adults in winter. — Similar to the summer plumage, but head and 

 neck clouded with brownish gray; bill paler yellow or yellowish 

 white, more decidedly yellow on culmen and tomia. 



Young. — General color deep gray, nearly uniform on imder parts 

 but on upper parts broken by a coarse irregular spotting or mottling 

 of grayish white or pale dull buffy, the head and neck indistinctly 

 streaked; primaries and rectrices plain pale brownish gray, with a 

 slight glaucous cast, the outermost rectrices more or less distinctly 

 mottled with paler; bill blackish, paler basally; legs and feet brownish 

 (in dried skms). 



Immature.— Back, scapulars, etc., mixed pale gray and brownish 

 gray or grayish brown; primaries and tail uniform brownish gray; 

 head and neck grayish white clouded with brownish gray; rnider 

 parts nearly uniform brow^lish gray; bill yellowish for basal half and 

 tip, the intermediate portion dull blackish; legs and feet dull brownish 

 (in di-ied skins). 



Downy young. — Head, neck, and under parts dull buffy white, 

 deepening mto very pale buft'y grayish on back, rump, and flanks; 

 pileum and sides of head with a greater or less number of well-defined 

 irregular spots of black, one on median portion of forehead, at base 

 of culmen, the arm -wing with several large blackish or dusky spots, 



