Viduidae – Indigobirds & Whydahs

The Viduidae (Indigobirds & Whydahs), are a family of small passerine birds native to Africa. They are finch-like species which usually have black or indigo predominating in their plumage. The birds named ‘whydahs’ have long or very long tails in the breeding male. At times treated as part of Estrildidae, the parasitic viduid finches are here treated as a distinct family, which is pretty clearly sister to Estrildidae.

Whydahs and indigobirds live in a variety of terrestrial habitats but show a preference for open areas, including savanna, scrub, grassland, and agricultural areas. They feed primarily on seeds, but also will take fruits and insects. During termite hatches, birds will take advantage of this momentarily abundant food source. Whydahs and indigobirds are promiscuous, with males courting several females and females occasionally mating with several males.

All are obligate brood parasites, which lay their eggs in the nests of estrildid finch species; most indigobirds use firefinches as hosts, whereas the paradise whydahs chose pytilias. Unlike the cuckoos and honeyguides, the indigobirds and whydahs do not destroy the host’s eggs and the host pair are often able to raise some of their own chicks successfully as well as those of the parasite. Typically, they lay 2–4 eggs in with those already present. The eggs of both the host and the victim are white, although the indigobird’s are slightly larger. The exception is the Cuckoo Finch as the females remove the host’s eggs before laying her own.

Pin-tailed Whydah Vidua macroura	Broad-tailed Paradise Whydah Vidua obtusa
All photos in this text courtesy of Dubi Shapiro

Many of the indigo-plumaged species named ‘indigobirds’ are very similar in appearance, with the males difficult to separate in the field, and the young and females near impossible. The best guide is often the estrildid finch with which they are associating, since each indigobird parasitises a different host species. For example, the Village Indigobird is usually found with Red-billed Firefinches.

Wilson’s Indigobird Vidua wilsoni

Indigobirds and whydahs imitate their host’s song, which the males learn in the nest. Although females do not sing, they also learn to recognise the song, and choose males with the same song, thus perpetuating the link between each species of indigobird and firefinch. The nestling indigobirds mimic the unique gape pattern of the fledglings of the host species.

The matching with the host is the driving force behind speciation in this family, but the close genetic and morphological similarities among species suggest that they are of recent origin.