LARUS. 25 



with gray, and a dark plumbeous suffusion before and behind eyes. Young : 

 Somewhat like winter adult, but lower part of hind-neck crossed by a black 

 patch, the anterior lesser wing-coverts black, and tail with a broad black 

 band at tip. Downy young : Head, neck, wings, and lower parts immaculate 

 white, the hind-neck and basal portion of wings more or less tinged with 

 buff; back, rump, and flanks yellowish gray, the down darker at base. Length 

 about 16.00-17.70, wing about 12.25, culmen 1.40-1.50, tarsus 1.30, middle toe, 

 with claw, 1.80. 

 b l . Hind toe absent, or very rudimentary. Eggs 2.26 X 1-61. Sab. Xorth 

 Atlantic, south, in winter, to middle Atlantic States and Great Lakes. 



40. R. tridactyla (Linn.). Kittiwake. 

 b*. Hind toe well developed, though minute, and usually armed with a distinct 

 nail. Eggs 2.36 X 1-63. Bab. Bering's Sea and Xorth Pacific. 



40a. R. tridactyla pollicaris Stejn. Pacific Kittiwake. 

 a 1 . Legs and feet bright red (becoming yellowish in dried skins). Summer adult .- 

 Pure white, the mantle dark bluish gray, or plumbeous ; five innermost quills 

 plumbeous, the inner webs broadly edged with white, the outer tipped with 

 the same ; five outermost quills black toward ends, the third, fourth, and 

 fifth tipped with plumbeous. Winter adult : Similar, but hind-neck and 

 auriculars washed with plumbeous. Young : Similar to winter adult, but 

 hind-neck crossed by a blackish band, ear-coverts crossed by a smaller black 

 band, and a suffusion of same in front of eye. (No black or dusky on wing- 

 coverts or tail.") Downy young : Not distinguishable from corresponding stage 

 B. tridactyla (?). Length about 14.00-15.80, wing about 13.00, culmen 1.20, 

 tarsus 1.25, middle toe, with claw, nearly 2.00. Eggs 2.28 X 1-66. Sab. 

 Coasts and islands of Bering's Sea. 



41. R. brevirostris (Bruch). Red-legged Kittiwake. 



Genus LARUS Linnets. (Page 23, pi. VIII., figs. 3, 4; pi. IX., fig. 3.) 



Species. 1 



West a rudely constructed platform of rubbish (sticks, dried grass, etc. — the 

 materials varying according to the locality and the species), slightly hollowed, 

 placed among rocks, in marshes, or other localities near the sea-shore or other large 

 bodies of water. Eggs 2-4, ovate, their ground-color some shade of pale brownish, 

 olive, light bluish, greenish, or buffy, irregularly spotted or blotched with brown 

 and lavender-grayish. 



a\ Head entirely white in summer. 



b 1 . Under wing-coverts entirely pure white; head, neck, entire lower parts, 

 tips of secondaries, rump, upper tail-coverts, and tail uniform pure white; 

 mantle (i.e., back, scapulars, and wings, except primaries) uniform gray- 

 ish, varying in shade from pale pearl-gray to deep slate. 

 c 1 . Primaries uniform pale pearl-gray, fading gradually into white at tips. 



1 The young birds of this genua seldom offering very obvious distinctive characters, this analysis is based 

 on the adults alone. 



4 



