Social constraints on the onset of incubation in a neotropical parrot: a nestbox addition experiment

The impact of early onset of incubation was examined to determine whether it serves to protect eggs from dangers imposed by conspecifics in the green-rumped parrotlet, Forpus passerinus. Nestboxes with eggs were installed and observed for egg destruction and nest-site takeovers. Findings showed that egg destruction at the nestboxes occurred during daylight and all mortality was caused by green-rumped parrotlets. Lone males never caused destruction, although they frequently visited the nestboxes. No significant differences were found in the frequency of visitations of lone males.