FAM. LX. TERNS AND GULLS 



329 



E. Primaries pearl-gray, tipped with white but liaving distinct gray- 

 spaces on the outer webs 17. Kiunlien's Gull. 



E. Primaries with white tips and dusky or black spaces near tips (in 

 young sometimes all dark). (F.) 

 F. Shafts of the primaries white through the dark spaces in adult ; wing, 



17-20 long ; back dark slaty -black 18. Great Black-backed Gull. 



F. Shafts dark like the spaces. (G. ) 



G. Wing, 15J or more long 19. Herring Gull. 



G. Wing less than 15| long 20. Ring-billed Gull. 



H. Wing over 16^ long ; culmen over 2 15. Glaucous Gull. 



H. Wing under 16J long ; culmen under 2 16. Iceland Gull. 



GhiVia dlha) . — A large, rare, northern. 



13. Ivory Gull (39. 

 pure white gull with 

 black feet and yel- 

 low bill. The young 

 has some gray patches 

 on different parts of 

 the body, but espe- 

 cially at the tips of 

 the tail feathers and 

 primaries ; sometimes 

 the wing coverts have 

 black spots at their 

 tips. 



Length, 15-20 ; wing, 

 1.3| ; tail, 5| ; tarsus, 1| ; culmen. If. Arctic regions ; south in the Atlan- 

 tic to about the border of the United States. 



Ivory Gull 



Kittiwake 



white 



KittiwalEe 



iO. Ri.isa trkldctyla). — A three- 

 , with pearl-gray mantle, black 

 outer primaries, yellowish bill, 

 black feet. The hind toe is rep- 

 sented by a little knob. The 

 third to the fifth primary 

 have white tips be- 

 yond the black. In 

 winter the top of the 

 head and the back of 

 the neck are tinged 



