( 361 ) 



LARUS TRIDACTYLUS— LINN. 



KITTIWAKE GULL. 



Larus tridactylus, Bonap. Syu. 



Lams tridactylus, Kittivvake, Sw. & Rich. 



Kittiwake, Nuttall. 



Kittiwake Gull, Lams tridactylus, Aud. Om. Biog. 



Specific Character — Hind toe wanting, substituded by a minute 

 knob ; bill rather strong, greenish-yellow ; head, neck all around, 

 lower parts, tail-feathers, and rump, pure white ; wings light o-ray- 

 ish-blue ; the outer vane of the first quill blackish-brown; the ends 

 of the outer five primaries blackish-brown — this color occupying 

 about two inches and a half on the first two, gradually lessenino- 

 on the next three, the tips of which are white ; feet black. Length 

 eighteen inches, wing eleven inches and a half. 



In winter, the head and neck are shaded with bluish-gray. 



Young, with the bill dusky ; a crescent of the same color before the 

 eye ; wings mottled with blackish-brown — outer quills the same 

 color, with a portion of their inner webs white. 



In this vicinity, the Kittiwake is not very common. It is more so 

 on the coasts of the Eastern States. According to Dr. Richardson, it 

 abounds in the interior of the Fur Countries, on the coast of the Pa- 

 cific, and also on the shores of the Arctic Seas, where it breeds. 



LARUS MARINUS— LINN. 



GREAT BLACK-BACKED GULL. 



Black-backed Gull, or Cobb, Nuttall. 



Great Black-backed Gull, Larus maribus, Aud. 



Specific Character — Bill along the gap three inches and a half, 

 much hooked and stout, tarsi three and a half inches. Adult male 

 with the head, neck, lower parts, rump, and tail feathers, white ; 

 back and wings blackish-purple ; edges of the wings and the ex- 

 tremities of all the quills white ; a broad band across the ends of 

 the second, third; fourth, and fifth primaries ; bill robust, gamboge 

 yellow, with a patch of carmine toward the end of the lower man- 

 46 



