78 The W'ji.sox Bur.LKTix — Xo. GT. 



FALCO ISLAXDUS (Briiiin). 



White Gvrfalcon. 



Geog'. Distrib. 



Arctic regions, including" Arctic America and Greenland, 

 accidental in British Columbia, Maine. Toronto; north to 

 81°5.V : breeding" in northern Greenland, Bering" Island ( lat. 

 55°) , Ungava Bay Labrador, Tuxsuk River, Alaska. 



[Measurements. 



Male; length 59.87 ctm ; extent 129 to 14U ctm ; wing 37 

 ctm ; tail 23.61 ctm; tarsus 5.-")3 ctm; middle toe 5.05 ctm; 

 culnien 2.31 ctm. 



Female: length 59.80 ; wing :'!)., SO ; tail 25.38 ; tarsus (3.12; 

 middle toe 5.32 ; culmen 2.59. 



Diagnostic I\Iarks. 

 Thighs and lower tail coverts pure white. Prevailng color 

 of plumage white. Large size.. 



Plumage. 



White, often pure, usually with dark markings. Adult ; 

 Top of head and neck narrowly streaked with dusky, upper 

 parts more or less transversely spotted or barred with slatish 

 dusky, lower parts no well defined markings. 



Young: nestling like adults (Chapman, Auk X\'1I, p. 387). 



Flight and Habits. 



Flight elevated, rapid beats then a short sail. I'old, strikes 

 its prey with 1)ullet-like swiftness (Authors) — "endurance 

 greater than swiftness, rather slow." (Kumlie.n) — sitting 

 like a Tern ; carriage otherwise noble and striking ; shy ; at- 

 tacks the Bald Eagle ; molested by the Raven ; living mostly 

 in pairs, seldom gregarious. Formerly much used in falconry. 

 Migrates at times. 



Food. 



All kinds of sea-birds, as auks, gulls, murres, sandpipers; 



