Mimicry and speciation in Africa’s parasitic finches: an exploration of indigobirds, whydahs and cuckoo finches
Africa is the continent with the greatest diversity of brood-parasitic birds on Earth. Brood parasites are species that forego their parental duties. Instead lay their eggs in the nests of other birds and force them to rear their young.
One of the most fascinating and species rich group of brood parasites in Africa are the parasitic finches. These consist of the whydahs, indigobirds and cuckoo finch. The indigobirds and whydahs (collectively known as Vidua finches) are remarkable in being extremely specialised brood parasites on hosts in the family Estrildidae (waxbills, firefinches, pytilias and twinspots).
Dr Gabriel Jamie, a research scientist at University of Cambridge and Fitzpatrick Institute of African Ornithology, has been studying Vidua finches for much of the past decade. In this talk, he will explore the intricate and highly specialised mimicry that nestling Vidua finches have evolved to deceive their foster parents and coerce them into providing food to an offspring that is not its own.
Gabriel will also discuss the amazing capacity Vidua have to imprint on their host’s vocalisations. When the males mature and start to display they imitate elements of their host’s vocalisations into their own repertoires. Therefore, male Vidua broadcast the identity of the host they were raised by to both female Vidua and to birders! This presents a unique opportunity amongst brood parasitic birds where patterns of host-use can be ascertained with relatively little effort – only sound recording rather than DNA analysis or nest finding is required.
Finally, Gabriel will explain the implications that host imprinting has for the origin of new Vidua species. Namely, that if a female Vidua accidentally lays in the nest of the new host she has the potential to initiate a new lineage of Vidua intimately connected to the new host species and reproductively isolated from other Vidua lineages. This can generate rapid speciation over the course of a single generation. Gabriel will explore this process in detail and highlight the amazing opportunities Vidua provide to study the process of speciation in action.