Changes in nesting numbers and breeding success of African White-backed Vultures in northern Botswana

Leepile, Leungo Boikanyo L

Changes in nesting numbers and breeding success of African White-backed Vultures in northern Botswana

Master Thesis

2018

Publisher

University of Cape Town

Department

Department of Biological Sciences

Faculty

Faculty of Science

Abstract

African White-backed Vultures have recently been uplisted to Critically Endangered by the IUCN due to declines across their range mainly linked to high levels of poisoning. Botswana likely supports significant numbers of this species, but as yet there is no published information on their population trends or their breeding success in this country. However, in recent years within Botswana and neighbouring countries there have been multiple incidents of mass poisonings, which have resulted in the deaths of thousands of White-backed Vultures. I therefore expected that nesting numbers of this species may have declined in this region, with potential additional negative impacts to breeding success. I used information from aerial surveys conducted between 2006 and 2017 in Khwai and Linyanti, two of the most important breeding areas for this species in northern Botswana to examine changes in nesting numbers and breeding success. The results showed a 53.5% decline in nesting numbers from these colonies, from 99 pairs in 2007 to 46 in 2017; with a greater decline in Linyanti than in Khwai. In both areas breeding success was significantly lower in 2017 than it was ten years ago. Current breeding success rates were generally lower than for other populations in South Africa. A population viability analysis suggested that if the productivity levels detected in 2017 were a true indication of current levels of productivity for this population, and if recent poisoning rates continue, this population has a high probability of extinction in the next 5 to 13 years.

Keywords

Conservation Biology

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