Penguin population models for Robben Island

As an initial illustrative exercise, a population model for Robben Island penguins, which includes dependency of reproductive success and survival rate on pelagic fish abundance, is fitted to moult count information for the colony. The results indicate a strong dependence of adult penguin survival rate on sardine abundance west of Cape Agulhas. However, the logistic transformation used to ensure respect of biological constraints on these demographic parameters leads to some problems in extending the approach to Bayesian estimation. Further work will explore use of the beta distribution and the incorporation of further data for the penguin population in the fitting process.