Hawks

Black sparrowhawks (Accipiter melanoleucus) recently colonised the Cape Peninsula, South Africa, where the species faces competition for their nest sites from Egyptian geese (Alopochen aegyptiaca) which frequently usurp black sparrowhawk nests. In this paper, we test the hypothesis that multiple nest building by black sparrowhawks is a strategy to cope with this competitor, based on a 14-year long term data set. Two main results support the hypothesis: first, the numbers of intact nests per breeding season in black sparrowhawk territories increased as levels of geese interactions increased, specifically when usurpation occurred. Usurpation occurred significantly more often at nests later in the season, and may provide a further explanation for the advancement of the black sparrowhawk breeding season towards earlier breeding attempts which results in an overall extension of the breeding period (over 9 months) that has been found in our study population. Second, nest usurpation had a ...

The record of Pseudolynchia canariensis on two Rufous Crab-Hawk in situ taken care of the Hospital Veterinarian of the RioZoo Foundation. The nineteen collected specimens had been identified in the Laboratory of Diptera, Fundação Instituto Oswaldo Cruz. The findings of P. canariensis out natural host (Columba livia) it represents a contribution to the studies of the family Hippoboscidae considering that it does not have records about native birds of the american continent parasitized by P. canariensis.

Predators may regulate prey populations if predation rate increases with prey density. Alternatively, if space-limited (e.g. territorial) predators become ‘satiated’ when prey exceed a certain density, increased prey abundance may lead to reduced predation rate. These alternatives have been difficult to test experimentally for mobile prey in the wild. We present such a test, manipulating the density of great tits