Survival in the orange-bellied parrot (Neophema chrysogaster)

Knowledge of demographic parameters, including survival, are fundamental to understanding the population dynamics of any taxon. Here we report on a long-term capture–mark–recapture study of the Orange-bellied Parrot (Neophema chrysogaster), one of the world’s most threatened parrots, using capture histories of 848 known-age wild birds. Parameter estimates of survival and probability of recapture were derived using the program MARK 4.1. Mean annual survival of juveniles and adults was estimated at 0.56 (s.e. 0.07) and 0.65 (s.e. 0.14) respectively. There was no evidence for an effect of sex on survival. Survival of three age-classes was estimated at 0.53 (s.e. 0.08) for juveniles, 0.64 (s.e. 0.11) for first-year birds and 0.59 (s.e. 0.09) for adults (2 years and older), indicating that maximum survival occurs in the second year of life, and declines thereafter. Although survival for both adults and juveniles varied considerably across years, there was no evidence of a decline in survival over the 20 years of the study. However, there has been an annual decline in the numbers of adult birds observed each year at the breeding grounds of 12% between 2000 and 2008, current survival rates do not appear to be a factor inhibiting population growth. The observed decline is more likely to result from a decline in female participation in breeding resulting in a decrease in the recruitment of juveniles to the population.