A nest parasite that lays its eggs in the nests of Bar-breasted Firefinch. Breeding males are glossy purplish-black with a pale brownish panel in the wings, while females and non-breeding males are brown and streaky on the back and pale below, with a bold facial pattern. The bill is white and the legs pinkish. Found in a wide variety of open habitats including open woodland, thickets, savanna, cultivated areas, and scrub. Breeding males can be identified with care by their vocalizations and purple gloss. Non-breeding males and females cannot be separated visually from other indigobirds. Imitates the vocalizations of its host firefinches: a low “chip” call and an up-and-down twittering song.