208 



grey ; wings and tail browner, latter barred 

 with bluish grey and tipped with white ; 

 below white with a broad slate brown 

 moustachial stripe, the breast and abdomen 

 with drop-shaped stripes and flanks barred ; 

 bill bluish, tip black ; feet yellow. 



f *310a. Falco rusticolus islandus [partim\ Briin- 

 nich, Orn. Bor., p. 2 (1764). [Iceland.'] 

 Iceland Falcon. 



[Grey-backed form]. SHghtly larger ; wing 

 ^ 368, ? 405 mm. ; above dark slate, barred 

 with greyish white, the head streaked with 

 dusky slate and bufhsh white ; chin and 

 throat white ; below white, chest streaked 

 and belly and sides spotted with slaty 

 black. 



Iceland ; 

 S. in winter to 

 Brit. Isles, 

 Europe and 

 N.E. America. 



310b. Falco rusticolus alascanus Swann, Bull. 

 B.O.C., xUi., p. 67 (1922). [$ Norton Bay, 

 Alaska, Oct. 1879, E. W. Nelson, type in 

 U.S. Nat. Mus., No. 96776.] 

 [nom. nov. pro F. sacer [Forster] of Ridgw., 

 nee auct.] 

 Alaska Gyrfalcon. 



[Grey-backed form]. Smaller ; wing S 

 340-358, tail 210 mm. ; wing ? 386-400, 

 tail 220-230 mm. ; wing (type) 400 mm. ; 

 darker, less grey than rusticolus, and with 

 bars on wing-coverts and secondaries rather 

 whiter and wider ; above blackish slate, 

 barred and edged with pale grey ; head 

 more uniform, hind neck mottled with 

 white ; rump lighter and bluer ; primaries 

 broadly barred with white on inner webs 

 and with obsolete spots on outer webs ; 

 tail evenly barred across with dark slate 

 and greyish white ; cheeks with distinct 

 black moustachial stripe ; below white. 



Alaska, breeding 

 S. to 



St. Michael's 

 and Norton 

 Bay, N. to 

 Anderson 

 River (?) ; in 

 winter to 

 S. Alaska, 

 Prybilov Is., 

 Brit. Columbia 

 and Washington 

 State. 



