Breeding biology of the Cape Bulbul Pycnonotus capensis: a 40-year comparison

Abstract

I examined the breeding biology of the Cape Bulbul Pycnonotus capensis at a study site in Port Elizabeth for a comparison with the results obtained by Richard Liversidge from a study made 40 years ago. There were no differences in methods, so results were directly comparable. No differences were found between the two study periods in the timing of breeding, clutch size, number of fledglings per nesting attempt or successful nesting attempt, indicating no major shift in the life history strategy or breeding success of the population. During my study period, there was a strong calendar effect on breeding success: early nests were more likely to be successful than late ones. I found strong differences between bush species with regard to predation risk and brood parasitism risk by the Jacobin Cuckoo Clamator jacobinus. These differences emphasise the complex interaction between the timing of breeding, risk of predation and risk of brood parasitism, which influences decisions about when to start nesting and nest site selection in the Cape Bulbul.