Managing a breeding population of endangered Carnaby’s Black–Cockatoo Calyptorhynchus latirostris on the edge of their range

Abstract

Context The Carnaby’s Black–Cockatoo Calyptorhynchus latirostris, an endangered species endemic to south-west Western Australia, has experienced a 30% contraction in range and 50% decline in population since the 1940s. A breeding population of Carnaby’s Black–Cockatoo was first described at Murchison House Station in the 1970s, but breeding had not been recorded there since the 1990s. Aims We sought to confirm whether Carnaby’s Black–Cockatoos were still breeding at this location at the far-northern edge of their range, hundreds of kilometres from the nearest known breeding site. Once confirmed, we compared population, hollow and nestling characteristics with those of other well-studied breeding populations of the same species and surveyed foraging and nesting habitat to evaluate population health and inform management. Methods We monitored 30 breeding attempts and characterised 21 confirmed hollows. We conducted comprehensive vegetation community surveys at nine sites. Key results We confirm that Carnaby’s Black–Cockatoos are still breeding at the far-northern edge of their range. Hollow and nestling characteristics are similar to breeding populations elsewhere. We found no evidence of plant recruitment for crucial foraging or nesting species. Conclusions The absence of plant recruitment in both foraging and nesting habitats suggests that active management will be required to support ongoing breeding. We recommend conserving and revegetating foraging and breeding habitat, maintaining hollows and/or providing artificial hollows while trees regenerate. Implications Foraging and breeding habitat will need long-term management to support ongoing breeding of this threatened species at the northern edge of its range.