White-winged Black-Tyrant Knipolegus aterrimus Scientific name definitions

Despite an unremarkable general impression, male White-winged Black-Tyrants are quite flashy birds. When perched, males appear plainly black with a slight gloss; however, a striking white wing patch formed by the white bases of the secondaries and primaries is evident in flight and during their flashy, acrobatic displays. As is typical of Knipolegus, the male's bill is blue gray with a black tip. Females are quite different, both in plumage and behavior. Whereas males favor obvious perches such as an isolated branch or a post; females are more retiring and are seldom as easy to see as males. Female plumage varies geographically and each of the three recognized subspecies are distinct. In the widespread nominate form found east of the Andes in a large area in southern South America, the female is largely cinnamon below, browner above, with cinnamon wingbars, rump, and base to the tail. The female of populations of the Andes of southern Peru and Bolivia (anthracinus) are duller, with restricted cinnamon at the tail base. Farther north in northern Peru (heterogyna) the female is very pale on the rump and base of the tail, and is creamy below with pale wingbars.