Abstract:
Obligate scavengers such as vultures provide critical ecosystem services and their populations have
undergone severe declines in Asia and Africa. Intentional poisoning is a major threat to vultures in
Africa, yet the impact on vulture populations of where poisoned carcasses are positioned is not known.
We used re-sightings of 183 African white-backed vultures captured and tagged in two regions of
South Africa, some 200 km apart, to estimate spatial differences in relative survival rates across life
stages. Juvenile survival rates were similar in the two regions, whilst subadult and adult survival rates
differed significantly. Using agent-based modelling, we show that this pattern of relative survival
rates is consistent between regions that differ in intensity of poisoning, despite the proximity of the
two regions. This may have important consequences for vulture conservation and the targeting of
conservation efforts, particularly with regard to the efficacy of “vulture safe zones” around vulture
breeding populations.
