Nestboxes have been deployed for parrots and cockatoos (Psittaciformes) worldwide, but there is limited evidence of their efficacy for these species. We examined the use of nestboxes by endangered ...South Australian Glossy Black Cockatoos Calyptorhynchus lathami halmaturinus, a habitat specialist that feeds almost solely on the seeds of Drooping Sheoak Allocasuarina verticillata trees, and investigated the factors that influenced nestbox use. Between 1998 and 2017, the mean annual proportion of nesting attempts that successfully fledged a chick was similar in nestboxes (52%, n = 547) and natural hollows (53%, n = 627). Nestbox use increased over time, which may reflect changes in the size and extent of the Glossy Black Cockatoo population over the study period. Nestboxes were more likely to be used by Glossy Black Cockatoos if they were close to the nest of another breeding pair and were not occupied by Yellow‐tailed Black Cockatoos Zanda funerea early in the breeding season. Nestboxes were also more likely to be used if they had been used in the previous breeding season, indicating nest‐site fidelity. The amount of A. verticillata feeding habitat in a 1‐km and 5‐km radius did not significantly influence nestbox use. Our study provides further evidence of the value of nestboxes to cockatoo conservation programmes, but also suggests that multiple factors other than local food availability influence uptake by a target species. Given that Glossy Black Cockatoos prefer to aggregate their nests, nestboxes for this species are most likely to be beneficial when they are used to expand the capacity of existing breeding areas or are clustered in the landscape. Our study demonstrates that well‐designed nestbox deployments should consider the preferred social groupings of cockatoos during the breeding season, and the location of competitor species, in order to maximize nestbox uptake.
Summary
Feral European Honey Bee (Apis mellifera) has been identified as a potential nest competitor for Australian hollow nesting species, but few studies have investigated the impact of feral honey ...bee competition on Threatened species. Our study used data from Glossy Black‐cockatoo (Calyptorhynchus lathami halmaturinus) nests on Kangaroo Island, monitored and managed over an 11‐year period, and found 12% of nests became occupied by feral honey bees during that period. Our results indicate that feral honey bees were less likely to occupy nest boxes made of PVC (5%) compared with wooden nest boxes (24%) or natural hollows in Eucalyptus trees (14%). The removal of feral honey bee hives from nests is a priority for long‐term conservation of glossy black‐cockatoos on Kangaroo Island. We recommend that PVC nest boxes are chosen for future nesting habitat restoration, due to the more frequent use of wooden nest boxes by feral honey bees.
The South Australian Glossy Black-Cockatoo Calyptorhynchus lathami halmaturinus is extinct on mainland Australia, and occurs only on Kangaroo Island. Between 1995 and 2016, a successful long-term ...Recovery Program more than doubled the population of this taxon on Kangaroo Island. This paper documents the first records of nesting by Glossy Black- Cockatoos on the Dudley Peninsula on eastern Kangaroo Island in 2015 and 2018, at a time when flock size had increased to 35 individuals in post-breeding counts on the Dudley Peninsula. Nesting there is evidence of the growth and expansion of the Glossy Black-Cockatoo population over the past 25 years, which is likely a result of conservation efforts. This new eastern nesting site expands the breeding range of this subspecies 13 km east, and to the part of Kangaroo Island that is closest to mainland South Australia.
