Nest parasite that lays its eggs in the nests of Red-billed and Brown firefinches. Breeding males are glossy black, while females and non-breeding males are streaky and brown on the back and pale below, with a bold facial pattern. The color of the bill is red in southeast Africa and whitish in western, northern, and central Africa. Found in savanna, scrub, farmland, and towns. Mimics the vocalizations of its host firefinches: low rattling series and high-pitched whistled notes. In southeast Africa, can be separated from other indigobirds by its red bill. Very similar to other indigobirds elsewhere on the continent. Breeding males can be separated by their all-black wings that lack a pale brownish panel. The mimicked vocalizations of its host species can also help confirm identification. In non-breeding plumage, similar to non-breeding Pin-tailed Whydah but separated by red legs.