The smallest of the five species of inca-finch, found only in the hot lower elevations of the Marañon Valley in the Andes of northern Peru. Handsome adult has a yellow bill and legs, a black mask, a rusty back, and white outer tail feathers that may only be evident in flight. Young birds are washed out and streaky, with less black on the face and duller bill and legs. Inhabits desert areas with scrub and abundant cacti. Feeds mainly on the ground, but often perches higher to vocalize or look around. Gives thin, high-pitched whistles, sometimes followed by a series of churrs.