A trial of release protocols for re-introduction of the bush stone-curlew to southern Australia

Summary

The bush stone-curlew (Burhinus grallarius), Least Concern nationally but Endangered in New South Wales and Victoria where feral predation and land clearing have driven steep declines, was the subject of a 2013 Australian Wildlife Conservancy trial release at Scotia Sanctuary comparing outcomes inside a 4,000-hectare fully predator-free fenced enclosure, already home to reintroduced marsupials, against an adjacent area with feral predators only suppressed. Twenty captive-bred birds from five breeding facilities were health-screened, DNA-sexed, split into two equal-sex groups, and held for at least 30 days in aviaries inside and outside the fence to acclimate and encourage flocking, before being fitted with bands and VHF transmitters and released in September 2013 with supplemental food provided for several weeks. Camera traps and radio tracking found survivorship was markedly worse inside the predator-free fence, where five of ten birds died within four to six weeks, mostly of starvation, compared to just one death outside; birds inside also showed lower site fidelity and less use of supplementary feed, apparently because reintroduced marsupials were outcompeting them for food, while VHF transmitters underperformed their expected range across both groups. By nine months post-release, call playback surveys at 53 sites detected no responding curlews anywhere on the property. The project rates itself a failure, concluding that food availability, not predation, was the critical limiting factor during establishment, compounded by competition from co-housed reintroduced mammals and a dry release year.