GULLS. 69 



feathers, and sometimes the wing-coverts, with a black spot at their tips. L., 

 17-00 ; W., 13-25 ; T., 5-50 ; B., T35. 



Range. "Arctic seas, south in winter on the Atlantic coast of North 

 America to Labrador and Newfoundland, casually to New Brunswick, and on 

 the Pacific side to Bering Sea " (A. 0. IL). 



Long Island, A. V., one record. 



Nest, of grass, moss, and feathers on rocky cliffs. Eggs, light yellowish 

 olive, marked with small blotches of brown and larger cloudings of lilac, 

 2-45 x 1-70 (Brewer). 



" The Ivory Gulls appear to spend most of the time amid the pack- 

 ice, often at a long distance from land" (Chamberlain). 



FIG. 60. First primaries of adult Gulls, seen from below: (a) Am. Herring 

 Gull ; (b) Ring-billed Gull ; (c) Laughing Gull ; (d) Franklin's Gull ; (e) Bona- 

 parte's Gull. 



40. Rissa tridactyla (Linn.}. KITTIWAKE. Ad. in summer. Head, 

 neck, tail, and under parts pure white ; back and wings pearl-gray ; outer 

 web of first primary and 3-00 of the ends of first and second primaries black ; 



