The influence of climate on Glossy Black-cockatoo reproduction

Abstract

Glossy Black-cockatoos Calyptorhynchus lathami are dietary specialists, feeding almost exclusively on the seeds of Allocasuarina and Casuarina species. Their specialized diet makes them vulnerable to alterations in their food supply, and populations inhabiting variable environments are good candidates for identifying reproductive strategies that match output to the available food supply. I studied reproduction in a population of Glossy Black-cockatoos in central New South Wales, a region where rainfall varies substantially between years and which is subject to periodic drought. Seed production in the principal Glossy Black-cockatoo feed species in the region tracks rainfall, and as a consequence, the Glossy Black-cockatoo food resource fluctuates between years. I monitored nest success and population structure between 1997 and 2004, a period that included wet and dry years. There was a strong relationship between cockatoo productivity and rainfall in the preceding year. The principal determinant of annual productivity was the number of pairs attempting to breed. Increased aridity as a result of climate change will have negative consequences for inland populations of Glossy Black-cockatoos. Careful management of their habitat will be required if Glossy Black-cockatoo populations are to persist in the long term.