Asia and Africa have experienced recent catastrophic declines in populations of most species of vultures (Thiollay 2006, Ogada et al. 2011, Virani et al. 2011). While the declines in Asia have been linked to poisoning by the veterinary drug diclofenac (Oaks et al. 2004), the reasons for the declines across Africa remain poorly understood (Ogada et al. 2011), and are likely to have multiple causes, such as poisoning and a decline in food supply.