Indigobirds and whydahs | Viduidae

Wida's | Viudas

Small seed-eaters with a thick, often coral-red conical bill, which build no nest and raise no young of their own. The female lays her white eggs in the nests of waxbills; the host pair incubates them and feeds the strange chick alongside its own, for nothing is turned out of the nest. This works because the chick matches its host down to the details: the same spots, blotches and coloured papillae at the back of the gaping bill, the same begging posture and the same begging call as the nest mates beside it. Each species is tied to its own circle of hosts, and the males take the song of their host into their own repertoire, so that females come to the right species. In the breeding season males wear black and white and, in some, greatly elongated tail feathers, used in a display hovering above the female; out of that season every species is streaked and sparrow-like, separable in practice only by bill colour.