156 FALCONS, HAWKS, EAGLES, ETC. 



1.08. Female: length 23-25, wing 15.25-17.75, tail 9.50-10.50, bill 1.00- 

 1.15. 



Distribution. — Eastern North America, west to the Black Hills and 

 Colorado, and south to northeastern Mexico. Breeds nearly throughout 

 its range. 



Nest. — Usually in tall trees. Eggs : 2 to 4, white or bluish white, 

 more or less spotted or blotched with brown. 



Food. — Mainly mice, ground squirrels, and other injurious mammals. 



The eastern red-tail goes as far west as Colorado. 



337a. B. b. kriderii Hoopes. Krider Hawk. 



Adults. — Under parts entirely white or pale buffy ; upper parts brown, 

 largely marked with white ; tail pale rufous, usually without subterminal 

 band. Young : similar, but tail tipped with white and with about ten 

 dark brown bands, feathers more or less tinged with reddish brown and 

 with inner webs largely white between bands. Size of B. borealis. 



Distribution. — Great Plains, from Minnesota to Texas, and from Wyo- 

 ming east casually to Illinois. 



Nest and eggs similar to those of the red-tail. 



337b. B. b. calurus {Cass.). Western Red-tail. 



Adults. — Varying greatly in plumage — Light extreme : under parts 

 white or buffy, with broad reddish brown streakings on throat, belly, and 

 sides ; tail bright reddish brown, with one or more subterminal blackish 

 bars ; rest of upper parts dark brown, more or less marked with yellowish 

 brown and whitish. Dark extreme : uniform dark sooty brown except for 

 rufous tail. Intermediates : reddish brown underneath, and with more or less 

 reddish brown wash on uj^per parts. There are also all grades of plumage 

 in this form between the light and dark extremes. Young : tail grayish 

 brown varying to dull yellowish brown, crossed by 9 to 10 blackish bands ; 

 rest of plumage dark brown heavily spotted beneath, sometimes wholly 

 duskv. Male : length 19.00-22.50, extent of wings 49-53, wing 13.50-16.50, 

 tail 8.50-10.00, bill .95-1.08. Female: length 23-25, extent 54.00-57.50, 

 wing 15.25-17.75, tail 9..50-10..50, bill 1.00-1.15. 



Distribution. — Western North America, from the Mississippi valley, 

 casually east to Illinois, west to the Pacific, and south to Guatemala. 



Nest. — Sometimes used a number of years, made of sticks and lined 

 with roots or inner bark, placed usually 30 to 50 feet from the ground, 

 generally in deciduous trees, but also in evergreens and giant cactus, and 

 occasionally on cliffs. Eggs : usually 2 or 3, creamy white or bluish 

 white, unspotted or irregularly blotched with yellowish and reddish brown. 



Food. — Rabbits, ground squirrels, chipmunks, mice, snakes, lizards, 

 frogs, grasshoppers, and other insects. 



"The western red-tail, though nowhere very abundant, is pretty 

 generally distributed over western North America at large, and is, 

 next to Swainson's haw^k, the commonest of the larger raptores found 

 in these regions. . . . It is fond of the tall timber bordering the banks 

 of streams, and is as often found far in the mountain passes and 

 deep canyons as in the more open country in the foothills and the 

 adjacent plains, but seems to shun the dense and extensive forests, 

 and is rarely seen except on the borders of these. In some of the 



