Evolution in aviculture: loss of genetic diversity and head-colour morph frequency divergence in the domesticated Gouldian Finch (Erythrura gouldiae)

Aviculturists are enthusiastic to be included in conservation efforts by providing expertise or genetic stock to support captive-breeding or reintroduction programmes, but little work has explored these possibilities. Bringing organisms into captivity can have rapid and profound effects on behaviour, physiology, and population genetic diversity, which can have important consequences for viability of reintroduction and the extrapolation of captive experiments to wild counterparts. The Gouldian Finch (Erythrura gouldiae) is a popular avicultural species that is endangered in the wild, and potential flagship for such reintroduction efforts. Here we used microsatellite and mitochondrial markers to characterise genetic diversity within and among avicultural populations in the broader population of domesticated Gouldian Finches in Australia, and with respect to natural head-colour morphs and artificially selected plumage variation. Domesticated Gouldian Finches have reduced the number of genetic variants by 32–48% compared to current wild populations, as well as high relatedness, and genetic structure among aviculturists. Indeed, regardless of collection size no aviculturist approached the total diversity held among all breeders. Head-colour genotype frequencies were substantially different from the wild, potentially due to selection or non-random mating in the domesticated populations. Given the previously established relationship between head-colour and functional traits, and possible adaptation to captivity, we suggest caution before introducing domesticated stock into the wild. Indeed, the status quo of relatively closed populations is potentially susceptible to inbreeding depression and further loss of genetic diversity, and we recommend a nationwide genetics-aware approach to any reintroduction programmes.