BIRDS OF NORTH AND MIDDLE AMERICA 233 



tinged with this cinnamon color; the cinnamon feathers with black 

 shaft streaks and some irregular dusky bars, tipped with whitish in 

 fresh plumage, the white tips soon wearing off completely; middle and 

 greater upper wmg coverts dark neutral gray to blackish slate as are 

 also the outer webs and broad tips of the primaries ; outer secondaries 

 tipped with whitish, secondaries and inner webs of primaries neutral 

 gray paling internally to grayish white, barred narrowly and tipped 

 broadly with dark neutral gray; lower back, rump, and upper tail 

 coverts white narrowly barred with dark gray especially on the upper 

 back and least so, often unbarred, on the upper tail coverts; rectrices 

 white darkening to pale neutral gray, especially on the outer webs 

 of the outer rectrices, the feathers tipped with white, and with a 

 broad subterminal black band; the rest of the feathers sparsely barred 

 with narrow, wavy dusky bars; chin and middle of throat, breast, 

 abdomen, sides, flanks, thighs, and under tail coverts white, more or 

 less (but always sparsely) barred with narrow dark gray or brownish 

 gray bars on the sides and flanks and thighs, but sometimes almost 

 immaculate white; sides of throat and breast neutral gray; axillars and 

 under wing coverts white narrowly barred with dark grayish or 

 brownish gray; iris hazel, cere pale green; bill black at tip, pale horn 

 at base; feet yellow; claws blackish. 



Adult (dark phase). ^^ — Similar to the pale phase but with the entire 

 underparts neutral gray to slate, the feathers of the abdomen and 

 thighs sparingly edged or barred with white, in some specimens the 

 thighs barred with rufous and white, and the abdomen and smaller 

 upper and under tail coverts somewhat suffused with rufous, the rest 

 of the tail coverts white barred with slate; rectrices white with eight 

 fine darker bars and broad black subterminal band.^* 



Immature. — Similar to adult but with the chin and middle of throat 

 deep neutral gray; the upperparts darker, dark neutral gray to dusky 

 neutral gray. 



Juvenal. — Entire head, nape, upper back, scapulars, interscapulars, 

 upper wing coverts, remiges, throat, breast, and upper abdomen dark 

 fuscous to fuscous-black, the upper wing coverts edged with light 

 cinnamon-buff, the feathers of the head and body with white bases, 

 which sometimes show through, the auriculars streaked with buffy 



23 None seen by me; description based on Gurney, Ibis, 1876, 73-76, pi. iii, and 

 Swann, Monogr. Birds Prey, i, 1928, 419. 



^* It is not wholly certain that this plumage (on which the name hypospodius 

 is based) is really a phase of Sennett's white-tailed hawk and not either a distinct 

 species or a phase of one of the southern races of Buteo albicaudatus, such as colonus 

 (which name would then have to be replaced by hypospodius, and sennetti rein- 

 stated for the northern race). I have seen one specimen of the race colonus in the 

 dark plumage, an adult female from British Guiana, now in the Cornell University 

 collection. 



