Feral Barbary dove phenotypes are lost following Eurasian Collared Dove invasions

Interactions between different non-native species can have positive and negative effects on their invasion potential and ecological impact. Here, we infer interbreeding of feral African Collared Doves (‘Barbary doves’; Streptopelia roseogrisea) and Eurasian Collared Doves Streptopelia decaocto, both of which have been widely introduced outside of their native ranges. Using plumage features visible on photographs submitted to citizen science databases, we argue that, where the two species mix, the African Collared Dove is absorbed into the gene pool of the Eurasian Collared Dove and is therefore experiencing ‘extinction by hybridization’ across parts of its non-native range. We discuss the implications of this and outline the importance of recording and quantifying interbreeding between different introduced or newly colonizing species more broadly.