AMERICAN ROUGH-LEGGED HAWK 273 



belly and head. The neAv plumage varies in color from "warm sepia" 

 to "Natal brown", edged or tinged on the head, breast, scapulars, 

 and wing coverts with "Mikado brown." Immature birds in this 

 phase are much like the adults, dark sooty brown above and below, 

 except that the feathers of the head, breast, tibiae, and bend of the 

 wing are edged or tipped with "tawny" ; some white shows through 

 on the under parts, and the tail is distinctly barred with gray on 

 the outer webs and with white on the inner webs. 



Immature plumages in the light phase are somewhat confusing, as 

 there is much individual variation, but there seems to be a second- 

 year, or subadult, plumage. The juvenal, or first-year, plumage is 

 variegated or patterned above with "clove brown", "hair brown", 

 and "smoke gray", with basal white showing through it; the under 

 parts are "cream-buff" or buffy white at first, fading to white, 

 streaked on the throat with "clove brown", heavily spotted or pat- 

 terned on the breast with "Natal brown" or "snuff brown", heavily 

 barred on the belly and tibiae with "bone brown" or "warm sepia" 

 and with some "tawny" on the tibiae; the tail is basally white and 

 tipped with grayish white; it has a broad, subterminal black band 

 and three to five narrow black bars, becoming broken inwardly, on 

 a white or grayish ground. 



Wliat looks like a second-year plumage, and is often regarded as 

 the adult plumage, is similar to that of the first year, but is lighter 

 on the head and neck, more buffy white and less dusky; the upper 

 parts are dark sepia with "tawny" edges ; the under parts, including 

 the legs, are pale buff or buffy white, heavily streaked, spotted, or 

 barred with "bister"; the large abdominal patches of "bister", so 

 prominent in the adult, are only partially developed ; the barring on 

 the white half of the tail is reduced to median spots, and the dusky 

 half of the tail shows indistinct grayish bars. 



In the fully adult plumage the head and neck are white or creamy 

 white, streaked with dusky bars, less heavily than in previous plum- 

 ages, the white predominating; the breast is less heavily streaked or 

 spotted with "bister" on a creamy- white ground; the abdominal 

 patches of "bister" are larger and of a purer color; the tibiae are 

 creamy, or buffy, white and nearly immaculate; the tarsi are the 

 same color and quite immaculate ; the inner two-thirds of the tail is 

 white and the outer third is dusky, usually with no conspicuous 

 barring in either zone. 



Adults evidently have a complete annual molt between April and 

 November. As this is mainly accomplished while the birds are on 

 their breeding grounds, molting birds are scarce in collections.] 



Food. — As before remarked, the rough-legged hawk is highly bene- 

 ficial to man in its feeding habits, as it preys on harmful rodents 



