The Persistence of an Apex Avian Predator, Verreauxs' Eagle,Aquila verreauxii, in a Rapidly Urbanizing Environment

Abstract

Anthropogenic land transformation processes in the vicinity of the Walter Sisulu National Botanical Garden, Johannesburg, South Africa, are a significant threat to natural vegetation and biodiversity. Breeding and feeding records of a Verreauxs' eagle (Aquila verreauxii),pair in the garden were analysed in relation to changes in the local environment due to urbanization. Natural prey-suitable habitat within a 10 km radius of the nest diminished by approximately 29.7 km2 (9.5%) during 1984–2007. In 2007 approximately 116.7 km2 (37.2%) of suitable prey habitat remained within this radius. Feeding data within a more recent period (1996–2008) suggest that there has been a switch from an optimal diet of rock hyrax (Procavia capensis)to less characteristic avian prey species such as helmeted guineafowl (Numida meleagris),francolins (Francolinus spp.) and supplemented food. Annual breeding success indicated few inconsistencies in incubation period, nestling period and postfledging dispersal period relative to br...