Breeding failure and nestling body mass as a function of age of breeding females in the endangered Carnaby's Cockatoo, Calyptorhynchus latirostris

The ecology of a population of the endangered Carnaby's Cockatoo, Calyptorhynchus latirostris, was studied from 1969 to 2015, with breeding data collected for 28 of those years. Data were available on the known breeding failure rates of females of known age (banded as nestlings in the study area) and females of unknown age (banded as adults), and on the condition of their nestlings, as assessed by the nestlings’ body mass and age. Females in their first two breeding years had failure rates four times that of older and more experienced females. Younger females (4 to 6 years old) were more likely to nest up to three weeks later than older females (7 to 27 years old), and the oldest females in the study area were more likely to nest three weeks later than those at least 10 to 19 years old. There was a trend for oldest females to produce lighter nestlings than young females. Despite the length of the study, few data are available on longevity in the species, other than one known age female breeding in her 27th year, and one female of unknown age breeding when she was at least 30 years old. Nestling body mass is a useful indicator of population health, and more breeding populations of Carnaby’s Cockatoo should be monitored to assess the likelihood of their persisting in the long-term.