Amount of Organic Waste Affects the Composition and Interactions of Vertebrate Scavengers at Gambian Slaughterhouses

Slaughterhouses in The Gambia serve as critical feeding sites for diverse vertebrate scavenger communities, including hooded vultures, domestic dogs, pigs and avian species such as pied crows, black kites and cattle egrets. This study investigated how the quantity and type of organic waste influence the composition and competitive interactions of scavengers across five slaughterhouses. Using multivariate statistical models, we found that waste quantity was the strongest predictor of scavenger community composition, explaining 32.7% of the variation, with hooded vultures being most abundant at high-waste sites. Specific waste types influenced feeding behaviour, suggesting niche differentiation among species; for instance, cattle egrets focused on blood and insects, while vultures dominated meat-based resources. Competitive interactions varied by species, with domestic dogs frequently displacing vultures without physical conflict, whereas hooded vultures dominated interactions against other birds. Activity patterns revealed temporal separation, with vultures and dogs active primarily in the morning, and other avian scavengers more active in the afternoon, reducing interspecific competition. The study highlights the essential role of hooded vultures in waste management and disease mitigation but also emphasises how poor fencing facilitates mammalian access, intensifying competition and potentially threatening obligate scavengers. Improving fencing, controlling feeding, and incorporating targeted waste management strategies are recommended to support scavenger conservation and enhance ecosystem services in urbanised environments.