Host species of brood-parasitic birds can evolve features such as spots, squiggles and colours on their eggs that act like ‘signatures’ that are difficult for parasites to forge, helping hosts to detect and reject imposter eggs. In this new paper, we show that hosts of cuckoo finches and diederik cuckoos in Zambia have optimised this defence by arranging signature traits in unpredictable combinations. Thus, egg signatures are individually distinctive and hard for parasites to mimic, helping hosts distinguish parasitic eggs from their own. The paper arose from MPhil research by Eleanor Caves (co-authored by Martin Stevens, Edwin Iversen and Claire Spottiswoode) and the data were all obtained from Major John Colebrook-Robjent‘s wonderful egg collection. It is available open access in Proceedings of the Royal Society of London B.
In a new paper published in Evolution, Dr Gabriel Jamie along with Silky Hamama, Collins Moya and Prof. Claire Spottiswoode from the African Cuckoos team and collaborators from University of Puerto Rico (Steven Van Belleghem), Princeton University (Dr Cassie Stoddard and Dr Ben Hogan) and University of Cambridge (Professor Rebecca Kilner) provide evidence of host-specific mimicry in the indigobirds and whydahs of Africa. Building on the pioneering work of Robert Payne and Jürgen Nicolai, they provide quantitative evidence that nestling Vidua finches mimic the patterns, colours and begging calls of their host’s nestling, and qualitative evidence of mimicry of host movements.