476 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



fulvous to buffy; outer six primaries sinuated on the inner webs, the 

 second, third, fourth, and fifth from the outside also sinuated on the 

 outer webs, the sixth only slightly so. The fifth primary the longest, 

 the third next in length, then the sixth; first primary not, or only very 

 slightly, exceeding the outer secondaries in length; upper tail coverts 

 like the rump; tail white, sometimes slightly mottled with dull sepia 

 at the base and v/ith occasional spots toward the tips of the feathers; 

 the older the bird the less mottling on the tail, which is pure white in 

 birds 5 years or more in age; chin, throat, cheeks, auriculars, and breast 

 similar to the crown and occiput, but with the shaft streaks slightly 

 broader and more brownish, less blackish. Abdomen, thighs, sides, 

 flanks, and upper tail coverts similar, but averaging slightly darker, 

 the feathers with paler tips which give a thumb-marked appearance; 

 the under tail coverts usually darker, more fuscous, than the rest 

 of the upperparts; under wing coverts similar to the abdomen; tibial 

 plumes extending two-thirds of the length of the tarsus; iris yellow; 

 bill, cere, and feet j^ellow; claws horn black; in fairly young adults, 

 that is, birds not more than 4 years old, but in adult plumage, the 

 culmen sometimes somewhat dusky. 



Immature (sexes alike) .—Generally similar to the adult, but with 

 the tail much mottled with brownish; the extent of the mottling 

 decreasing with successive immature plumages; the upperparts and 

 underparts of the body generally paler, more hght cinnamon brown or 

 isabelline and sometimes with a mixture of whitish, chiefly from the 

 concealed portions of the feathers ; the feathers of the top of the head 

 generally with less pronounced fulvous tips than in the adults. ^^ 



Juvenal (sexes alike) .—Feathers of the crown and occiput dark 

 sepia to chocolate-brown, toward the base of the margins slightly 

 more rufous and paler; the extreme bases of the feathers whitish; 

 the general plumage darker than the immature birds, the scapulars 

 and interscapulars with a slightly rufescent tinge; the tail feathers 

 very extensively mottled with dark fuscous often to the point of 

 almost excluding the white; feathers of the breast and upper abdomen 

 ochraceous-brown to fulvous, often with large and much darker sepia 

 tips; the rectrices fuscous to fuscous-black mottled extensively but 

 rather minutely with white, the white chiefly concentrated toward the 

 median part of the individual feathers ; iris dark brown; bill dusky horn 

 color; cere and feet yellowish; claws horn black. 



Natal down. — Dusky cream color usually grayer on the upperparts, 

 lighter on the head than on the body. 



Adult male.—SNiag 570-618 (597.5); tail 288-306 (294); culmen 



^^ It is difficult to work out with certainty any definite constant change between 

 successive immature plumages, but the relative age of the bird may be ascertained 

 by the amount of white, or, conversely, the decrease in the mottling, on the tail. 



