Reintroduction of wild song culture to a critically endangered songbird

Animal cultures are learned behaviours, traditions, and collective knowledge that are maintained within populations through social learning. Global biodiversity decline can lead to the loss of animal culture within small and sparsely distributed populations, making the conservation of animal cultures increasingly important. The Critically Endangered regent honeyeater (Anthochaera phrygia) is an Australian songbird whose population is declining to the extent that song culture is being lost in the wild. Reintroduced, zoo-bred males that supplement the wild population sing songs that differ from all wild birds, representing a significant cultural barrier that may impact their fitness after release to the wild. Over three breeding seasons within the applied breeding system, we undertook adaptive song tutoring experiments using combinations of song broadcast and live tutoring from two wild-origin males to teach zoo-bred juveniles the wild song. The proportion of juveniles that learned the wild song increased from 0 before the experiment to 42% after three years. The entire population is predicted to sing the wild song within two years. The full version of the wild song taught to zoo-bred males disappeared from the wild over the course of the experiment, making the zoo population the only remaining repository of traditional song culture. Using just two wild founders, we show how animal cultures can be restored in ex-situ populations with simple modifications to husbandry protocols. Ex-situ populations can then play important roles in the maintenance and restoration of wild animal cultures through reintroductions.