Diet plasticity of cinereous vulture aegypius monachus in different colonies in the Extremadura (sw Spain)

Abstract

The current feeding habits of the Cinereous Vulture Aegypius monachus remain largely unknown since most studies were carried out in the 1970s. To update the information, we studied the diet of the species in different colonies in Extremadura by analyzing the frequency of presence of 378 prey items observed in 283 pellets. In all colonies, sheep carcasses formed the staple food. Nevertheless, there were major differences between colonies in supplementary prey: farm poultry and swine in Sierra de Gata, swine and deer in Sierra de San Pedro and Granadilla. There were also variations between subcolonies within a colony and differences with colonies elsewhere in the Iberian Peninsula. In colonies situated in areas with a high abundance of lagomorphs and deer, such as Cabañeros and Sierra de Andujar, the diet is based on wild animal populations. In other colonies, the diet depends to a large extent on livestock farming: sheep in Sierra de Gata, Granadilla and Sierra de San Pedro, and swine and sheep in Sierra de Guadarrama. The Cinereous Vulture thus shows great trophic plasticity, taking advantage of new resources (such as carcasses of poultry from poultry farms) and responding to variations in prey availability in the area surrounding the colonies. These circumstances need to be taken into consideration for the conservation of the species, in particular when the vultures depend on human resources, which are prone to drastic changes in availability. The recent outbreaks of veterinary diseases (like BSE, foot-and-mouth disease, Rift Valley fever and bluetongue disease) and reforms related to the Common Agricultural Policy, are a point in case.