ORDER RAPTORES. 163 
b. Halizetus leucocephalus alascanus C. H. Townsenp. Northern Bald 
Eagle. [852a.] 
Halietus leucocephalus alascanus TOWNSEND, Proc. Biol. Soc. Wash., 
XJ, June 9, 1897, 145. (Unalaska, Alaska.) 
RanGE.— Boreal zones of northwestern Alaska, northwestern Mackenzie, 
central Keewatin, and northern Ungava south to British Columbia and the 
Great Lakes. 
Famity FALCONIDA. Fatcons, CARACARAS, ETC. 
SupFAMILy FALCONINAS. Fatcons. 
GENUS FALCO LINN2Uws. 
Falco Linnus, Syst. Nat., ed. 10, I, 1758, 88. Type, by subs. desig., 
Falco subbuteo Linnzsus (A. O. U. Comm., 1886). 
Suscenus HIEROFALCO Cuvier. 
Hierofalco Cuvier, Régne Animal, I, 1817, 312. Type, by monotypy, 
Falco candicans GMELIN = Falco islandus BRUNNICH. 
Falco islandus BRUNNIcH. White Gyrfalcon. [353.] 
Falco islandus BRUnNnIcH, Orn. Borealis, 1764, 2. (Iceland.) 
RanGe.— Arctic regions. Resident in Greenland; in winter 
casual south to Ontario, Nova Scotia, and Maine. 
Falco rusticolus LINN xUs. 
RanceE.— Arctic and subarctic parts of the Northern Hemisphere, 
south in winter to northern part of temperate zone. 
a. Falco rusticolus rusticolus Linnmus. Gray Gyrfalcon. [354.] 
Falco rusticolus Linnxus, Syst. Nat., ed. 10, I, 1758, 88. (Sweden.) 
RanGeE.— Arctic regions. Breeds in Arctic America from Alaska east to 
southern Greenland; in winter casual south to British Columbia, Kansas, 
Wisconsin, Ontario, and Maine. 
