Targeted nest predator management and zoo-bred supplementation in a Regent Honeyeater (Anthochaera phrygia) breeding event

Abstract

ABSTRACT Nomadic species are challenging to conserve, because their high mobility and irregular settlement patterns make it difficult to implement targeted conservation actions. Here, we report on the first sustained attempt to protect nests of Critically Endangered Regent Honeyeaters from predation and to release zoo-bred birds into a wild breeding event. During the 2023 breeding season, targeted culling of known nest predator species within the area of 10–12 wild breeding pairs within Capertee National Park was associated with a daily nest survival rate of 97.9%. This equated to an overall nest success rate of 48.6% and resulted in the fledging of 18 juveniles from nine nests – double the average nest success rate from 2015, 2016 and 2017 (24.1%) when Regent Honeyeaters bred in the same location. Population viability analysis indicates nest protection alone could slow the rate of population decline, but its effectiveness depends on the proportion of nests that can be located and protected each year. Fourteen zoo-bred Regent Honeyeaters were released approximately half way through the breeding event. Seven zoo-bred birds were confirmed alive 5 weeks post-release, but no zoo-bred birds released in 2023 attempted to breed in this year. Although our sample is small and prone to stochastic effects, we provide non-experimental evidence that nest predator management can play a key role in boosting recruitment of juvenile Regent Honeyeaters to the wild population. In combination with the reintroduction of zoo-bred birds and habitat restoration, nest predator management can help prevent imminent extinction of the Regent Honeyeater.