Mapping suitable habitat for Hooded Vultures Necrosyrtes monachus in one of the last West African strongholds for the species, The Gambia

Abstract

Hooded Vultures Necrosyrtes monachus are Critically Endangered, with numbers decreasing due to illegal poisoning, hunting for belief-based use and food, and habitat loss. In The Gambia, human activities currently benefit commensalism between humans and Hooded Vultures, as these birds primarily feed on carcasses and organic waste found around human settlements. This study aimed to identify suitable habitats for Hooded Vultures in The Gambia and assess the importance of environmental variables for habitat suitability. We surveyed 791 km of roads by car in 2017 and 2021 for signs of vulture occurrence (n = 179). Occurrence data were combined with 15 environmental variables using the Maximum Entropy species distribution model (MaxEnt) to predict suitable habitats. We found that 43.7% of the country is unsuitable as habitat for Hooded Vultures, 27.1% is of low suitability, 17.6% is of moderate suitability, and 11.6% is of high suitability. Highly suitable vulture habitats were identified in the western region and the greater Banjul area. The likelihood of vulture occurrence increased with the density of built-up areas and proximity to roads but decreased with the density of water bodies. Vulture habitats are limited across the country and are constrained to certain climatic conditions in areas of intense human settlement, such as arid and semi-arid regions with low rainfall and high temperatures. Although the commensal relationship with humans brings benefits to the vultures, it also exposes them to human-caused threats that can reduce their survival. Our results suggest that urban planning, waste management, and climate impacts should be considered in their long-term conservation planning.