BUTEO. 235 



times among rocks. Eggs 2-4, 2.23 X 1.73, white, dull glau- 

 cous white, or buffy white, usually more or less spotted with 

 brown. Sab. Western North America, north to Alaska and 

 western side of Hudson's Bay, east to Wisconsin, Illinois, and 

 Arkansas (casually to Massachusetts), and south through Mid- 

 dle America and greater part of South America to Argentine 



Eepublic 242. B. swainsoni Bonap. Swainson's Hawk. 



b\ Wing less than 13.50. 



c\ Middle toe longer than bare portion of tarsus in front. (Subgenus 

 Buteola Bonapabte.) 

 Adult : Above sooty blackish or blackish brown, the feathers of 

 occiput pure white beneath surface, and the frontlet usually 

 more or less conspicuously whitish ; tail slaty grayish, varyino- 

 to grayish brown, very narrowly tipped with white, and broadly 

 banded with black, the black bands sometimes wider than the 

 grayish interspaces, the latter 5-7 in number. Young with 

 tail more narrowly banded, the grayish brown bands usually 

 broadest, and 8-9 in number. 



d 1 . Lower parts black, or dark sooty brown, like the upper; 

 young with feathers much spotted, beneath surface with 

 white, the lower parts sometimes slightly varied with 

 white and ochraceous, the under wing-coverts sometimes 

 spotted with same. Male: Wing 11.20-11.70, tail 7.00- 

 7.30, culmen .70-.75, tarsus 2.05-2.25, middle toe 1.35-1.40. 

 Female: Wing 11.90-13.10, tail 7.50-8.00, culmen .78-.85, 

 tarsus 2.50-2.65, middle toe 1.50-1.60. Sab. Tropical 

 America in general, except West Indies, north to north- 

 ern Mexico and (casually ?) southwestern Florida. 



— . B. fuliginosus Scl. little Black Hawk. 1 

 d 2 . Lower parts white. Adult male : Forehead, anterior portion 

 of lores, fore-part of malar region, and lower parts gen- 

 erally, immaculate pure white; sides of chest with a 

 patch of rufous or cinnamon, the feathers with dusky 

 shaft-streaks; wing 10.50-12.00, tail 6.00-7.00, culmen 

 .68-.75, tarsus 2.05-2.30, middle toe 1.35-1.40. Adult 

 female : Similar to the male, but sides of chest grayish 

 brown instead of rusty. Wing 12.70, tail 7.20, tarsus 

 2.30, middle toe 1.55. Young : Above dull brownish, the 

 scapulars, wing-coverts, etc., usually margined with buffy 

 or light fulvous, the top and sides of head and neck 

 streaked with same ; lower parts white, sometimes 

 streaked with brownish, the sides of chest without brown 

 or rusty patch. Sab. Tropical America in general (except 



1 Buteo fuliginoeua Scl. P. Z. S. 1858, 356. (Said to be the black phase of B. brachyuriw Vieill.) 



