The Western Red-tailed Hawk 



thicket. This thicket bordered upon a lagoon, one of the overflow 

 channels of the Colorado, and was not far from some houses, although 

 the birds were clever enough to keep quiet and not to appear near the 

 settlement itself. On the 27th of April the eggs hatched and the young- 

 sters were seen to be covered with a light buffy down. 



This species was early reported from northern Lower California, but 

 was never known to have crossed the line west of the mountains till 

 Mr. Harvey Grey secured a specimen, 1 a male in full plumage, in the 

 Mission Valley near San Diego, Nov. 17, 1912. 



No. 331 



Western Red-tailed Hawk 



A. O. U. No. 337b. Buteo borealis calurus (Cassin). 



Synonyms. — Western Red-tail. Western Red-tailed Buzzard. Black 

 Red-tail. Chicken Hawk. Hen Hawk. 



Description. — Adult, light phase: Above dark brown or sooty brown, color 

 nearly pure on upper back, upper scapulars, and minor wing-coverts, elsewhere much 

 varied by lighter grayish brown, tawny, and outcropping white; basal white out- 

 cropping regularly on hind-neck; tawny most extensive on sides of neck and on cervix; 

 longer scapulars and tertials dusky and white, and double tawny-barred; wing-quills 

 blackening on exposed tips (often with violaceous or purplish reflections), faintly 

 banded basally on outer webs, distinctly dusky and white on inner webs; 1st primary 

 shorter than or about equal to the 8th, the point of the wing formed by 3rd, 4th, and 

 5th, the 2nd longer than the 6th; when folded usually but not always falling two or 

 three inches short of end of tail; the first four primaries deeply emarginate on the 

 inner web, the 2nd to the 5th lightly emarginate on outer web; tail rich orange-rufous, 

 crossed near tip by narrow black band, and with suggestions of former (juvenile) 

 black bands persistent in spots along sides of shaft, especially basally; upper tail- 

 coverts like tail in color, or a little lighter, and obscurely dusky-banded; underparts 

 white, variously broad-marked or washed, except on throat, with pale cinnamon- 

 rufous, most heavily on sides of breast, where also broad-marked with dusky; throat 

 and breast sparingly marked with blackish shaft-streaks; shafts on flanks deep rusty; 

 flanks and shanks finely wavy-barred in two shades of pale rufous. Bill plumbeous; tar- 

 sus yellow, very stout; claws black. Adult in (common) melanistic phase: Entire plum- 

 age, except tail audits coverts, chocolate brown, rich sooty brown, or blackish, rich deep 

 rusty usually warming on breast, and lighter rufous appearing on shanks. Between 

 these two plumages many gradations exist. Erythrism, or a tendency to reddening 

 of plumage, is noticeable in many dark-colored specimens, while albinism of some 

 degree is not rare. Immature: Above much as in adult, but showing less of tawny 

 and more of outcropping white; tail entirely different, grayish brown crossed by ten 

 or twelve brace-shaped or waved bands of dusky; upper tail-coverts lighter, dusky- 

 and-whitish-barred, with mixture of ochraceous; underparts white or pale ochraceous 

 buffy, heavily streaked, spotted, and posteriorly barred with dark brown, except on 



1 Condor, Vol. XV., p. 128. 

 l674 



