68 



GULLS. 



|i ' 



I 



6». Primnrics pearl-gray, tipped with white, and with well-defined 

 gray spaces on tlio outer webs of the two outer primaries and on 

 both webs of the third and fourth pritiiurieH. 



45. Ki'mlien's Gull. 



c>. Bill over 200 42. Glaucous Gull. 



C. Back grayisli, whitish, or brownish, or mottled or spotted with gray- 

 ish or brownish. 



a. Tail black or blackish, with or without irregular white markings, 

 a*. Wing over 17*50 ; depth of bill at nostril over -70. 



47. Black-hacked Gull (Im.). 

 a«. Wing under 17'50; depth of bill at nostril under "70. 



51a. Am. IIekkinu Gill (Iul). 51. IIekkinu Gull (Iul). 

 h. Tail white or whitish or grayish brown, with or without black 

 nuirkings. 



6'. Bill under 2*00 43. Iceland Gull (Im.). 



i«. Bill over 2'00 42. Glaucous Gull (Im.). 



II. Wing under 15-00. 



1. Tail pure white. 



A. Head and throat slaty black. 



a. Outer primary black or mostly black. 



a>. Outer primary entirely black .... 58. LAuaniNo Gull. 



a». Inner half of inner webs of first primary white. 



02. Sabine's Gull. 

 6. Outer primary mostly white. 



lA. Tip of first primary white 59. Fuanklin's Gull. 



i'. Tip of first prinuiry black CO. Bon ai'akte's Gull. 



B. Head white, sometimes washed with pearl-gray. 



o. Wings white 39. Ivouy Gull. 



h. Primaries with more or less black. 

 A". Wing over 1100. 

 J«. Hind too very small, without a nail ... 40. Kittiwake. 

 *». Hind toe normal, with a nail ... 54. Rino-billed Gill. 

 c». Wing under 11-00 61. Ross's Gull. 



2. Tail marked with black. 



A. Wing over 13-25. 



a. Priniaries mostly white ,39. Ivoky Gull (Im.). 



h. Primaries black or mostly black . 54. Rino-billed Gull (Im.). 



B. Wing under 13-25. 



o. Hind toe very small, without a nail . . . 40. Kittiwake (Im.). 

 h. Hind toe normal, with a nail. 



i». Tarsus 1-50 or over 58. Lauguino Gull (Im.). 



c>. Tarsus under 1-50. 

 A Secondaries pearl color, tail square. 



60. Bonaparte's Gull (Im.). 

 «•. Secondaries mostly white, tail rounded. 



61. Ross's Gull (Iin.). 



80* GaiVia> alba ((funn.). Ivory Gull. Ad.—EntWa plumage pure 

 white; bill yellow, feet black, /w.— Similar to ad., but the wing and tail 



