209 



chest streaked, breast and under wing- 

 coverts spotted, and flanks barred with 

 black ; thighs and under tail-coverts 

 strongly barred with blackish slate ; bill 

 bluish, tip black. Juvenile : above dark 

 brown, unbarred at first ; tail with fainter 

 and narrower bars ; below whitish, heavily 

 and broadly streaked all over with dark 

 brown. More mature birds have the upper 

 parts of a more blackish brown than grey 

 shade until quite old, the bluish shade 

 being then most evident on the rump. 



t*310c. Falco rusticolus candicans Gmel., S.N., i., 

 p. 275 (1788). [" Islandia et Scotia," errore, 

 type loc. subst. Hartevt— Greenland.] 

 Greenland Falcon. 



[Albinistic form]. Larger ; wing S 365- 

 380, ? 408-428 mm. ; bill yellow in old 

 birds ; [white phase] : general colour pure 

 white ; the feathers above mostly marked 

 with a black or dark brown bar or spot 

 towards tip ;| head with a few streaks of 

 black ; tips of primaries black, inner webs 

 usually with notches obsolete ; tail white 

 with more or less obsolete bars on central 

 feathers ; below white, usually with a few 

 blackish or brownish striations and spots on 

 sides. [Dark or primitive phase] : above 



Circumpolar ; 

 breeding in 

 Greenland, 

 Labrador and 

 Arctic America 

 (E. of Alaska), 

 Arctic Europe 

 and Asia^ 

 (Spitsbergen (?), 

 Novaya Zem- 

 bla (?) ; E. to 

 Kamtschatka 

 and Bering Is.) ; 

 in winter to 

 Brit. Isles, 

 N.W. Europe, 

 Canada and 



^ If the Asiatic birds south of the polar circle are a constant grey-backed race, 

 and distinguishable as a dark breeding race, they would be called Falco rusticolus 

 utalensis (Sewertz. and Menzb.), [Orn. Geogr. Europ. Russl., i., p. 288, tab. 3 (1882) — 

 Ural Mtns., Russia'\, but we lack data as to this and only know that both grey- 

 backed and white birds occur in Arctic Asia. On Bering Island, according to 

 Stejneger, the white bird breeds and not the grey-backed one, which he says only 

 comes in winter. The latter has been named F. grebnitzkii (Sewertz.), but the name 

 is a synonym of uralensis. I have examined two white resident birds and three 

 immature birds in the United States National Museum, and find them smaller 

 than usual candicans (wing (J 358-362, ^ 385-400), but at Tring are both grey-backed 

 and larger white winter birds from Bering Island. The name obsoletus of Gmelin, 

 it should be stated, has 7 pages priority over candicans, but is based on the melanistic 

 variety, and is for that reason best discarded in favour of candicans. 



