7/ 



143. Butco borealis borcalis ((imel. 

 p. 266 (1788). [Carolina. \ 

 Red-tailed Hawk. 



). S.N., 1, 



Size variable ; wing S 390-400, ? 440-450 

 mm. ; above blackish-brown with more or 

 less of lighter variegation ; tail chestnut 

 with one sub-terminal darker band and 

 often remains of others ; below buffy- 

 white, flanks barred or mottled and abdo- 

 men heavily streaked with blackish-brown. 



E. Noith 

 America, N. to 

 Canada and 

 Newfoundland, 

 W. to Gt. Plains. 



■143a. Butco borealis kridcri Hoopes, Pr. Ac. Nat. 

 Soc. Philad., 1873, p. 238, pi. 5. [Winne- 

 bago Co., Iowa, type in Phil. Ac. Mus.] 

 Krider's Hawk. 



\Mng o 370, ? 400 mm. ; light form, pure 

 white below with few or no markings ; 

 tail pale rufous to grey or white, with 

 blackish bars more or less obsolete and 

 sub-terminal bar reduced or obliterated. 



Gt. Plains from 

 Missouri and 

 Minnesota to 

 Rocky Moun- 

 tains, N. to S, 

 Manitoba ; S. 

 in winter to 

 Mexico and 

 Georgia. 



143b. Butco borealis lucasa>ius Ridgw. Hist. N. Peninsula ot 



Am. Birds, iii., p. 285 (1874). [Cape St. Lower 



Lucas.] California. 

 St. Lucas Red-tail. 



Like B. b. calurus but lighter and smaller ; 

 wing S 370-398, 2 395-420 ; sub-terminal 

 tail band reduced. 



*jl43c. Buico borealis calurus Cassin, Proc. Ac. 

 Nat. Sci. Philad., \di., p. 281 (1855). [Near 

 Fort Webster, New Mexico, type in Phil. Ac. 

 Mus.] 

 Western Red-tail. 



Wing (J 386, $ 412-430 mm. ; strongly de- 

 veloped form of B. borealis borealis, more 



\\'. North 

 America,beyond 

 W. edge of Gt. 

 Plains, E. to 

 Middle Yukon, 

 S.to Guatemala; 

 Guadeloupe Is, 



