THE NESTING ECOLOGY OF VULTURES: A GLOBAL REVIEW OF BREEDING BIOLOGY AND SITE SELECTION

Vultures are obligate scavengers, which are essential ecologically because they contribute important functions in the cycling of nutrients and in controlling diseases, but their population is experiencing unprecedented reductions worldwide. Their nesting ecology is important to successful conservation management. This review integrates existing information on the vulture breeding biology, nest site choice, and reproductive performance based on 35 studies involving Old World (Accipitridae) and New World (Cathartidae) species of vultures. We test the effect of environmental and anthropogenic variables on the selection of nest site, breeding phenology, and reproductive success in different geographic locations. Cliff-nesting birds (e.g., Gyps spp., Neophron percnopterus, Gypaetus barbatus) show considerable preferences to steep and remote locations that are undisturbed by human activity, whilst tree-nesting birds (Aegypius monachus, Necrosyrtes monachus) choose mature woodland patches with defined structural features. The success of breeding is significantly different between species and areas (0.34-1.20 fledglings per breeding attempt), and human disturbance, poisoning, loss of habitat and climate-related reasons were found to be the main threats. Human activities between 300 and 800 m of nests have a great impact on the productivity of the nests, and the forestry activity, recreational activities and construction of infrastructure lead to abandonment of nests and breeding failure. Critical knowledge gaps that we recognize are in the ecology of New World vulture nesting, the effects of climate change, and the density-dependent processes. The conservation strategies also focus on the creation of disturbance-free buffer strips, safeguarding prime nesting areas, reducing the risk of poisoning and the use of adaptive management techniques. This synthesis offers a basis of evidence-based conservation planning to protect the populations of vultures and the ecosystem services they offer.