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1 April 2012 The Persistence of an Apex Avian Predator, Verreauxs' Eagle, Aquila verreauxii, in a Rapidly Urbanizing Environment
Craig T. Symes, Tamara L. Kruger
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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 breeding Verreauxs' eagle elsewhere. Despite a reduction in the suitable prey habitat and change in prey composition (including supplemental feeding), breeding has persisted successfully over a 16-year period (1993–2008). The presence of a large apex avian predator in an extensively urbanized metropolis is encouraging with regard to ecological integrity and functioning but the future prospects for these Verreauxs' eagles may depend on an as yet unknown threshold of prey abundance, both natural and supplemented, and environmental disturbance.

Craig T. Symes and Tamara L. Kruger "The Persistence of an Apex Avian Predator, Verreauxs' Eagle, Aquila verreauxii, in a Rapidly Urbanizing Environment," South African Journal of Wildlife Research 42(1), 45-53, (1 April 2012).
Received: 1 November 2011; Accepted: 1 April 2012; Published: 1 April 2012

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