SocForVul · The impact of supplementary feeding on the food searching strategies and social behaviour in an endangered top scavenger

The impact of supplementary feeding on the food searching strategies and social behaviour in anendangered top scavenger

The provision of surplus food at supplementary feeding stations is a worldwide practice to facilitate the recovery of endangered species like vultures, which have experienced dramatic population declines during the past century. Despite considerable research on the effects of supplementary feeding on the viability of populations, there is almost a total lack of knowledge on the effects of these practices at the individual level. The main aim of this project was to investigate the impact of supplementary feeding on food searching behaviour and the social dynamics of the endangered Canary Egyptian Vulture. The species is considered endangered worldwide, but 60 breeding pairs and a total population of about 300 individuals still occur on Fuerteventura (Canary Islands, Spain). Extensive field-work over the past 20 year has resulted in most birds being individually marked with plastic rings (>85%), 45 of them carrying GPS-transmitters. As such, this population is a case unique among vultures in the world allowing complex approaches to individual movement and foraging behaviour in relation to the spatial distribution of trophic resources. Changes in food predictability caused by supplementary feeding were found to lead to sex-specific patterns of resource partitioning within population through effects of social status. However, the presence of predictable feeding stations did not exert a constant influence on individual mobility, implying that, at least on Fuerteventura, the impact on population movement dynamics seems rather minimal. Although these findings contrast the popular claim that supplementary feeding may create a large-scale dependence on surplus food and leads to strong reductions in mobility, the asymmetric use of predictable food provide a cautionary note for the implementation of feeding stations. First, the sex-specific dominance effects on resources use may potentially lead to differential mortality traits among males and females. Secondly, we also found that dominant females bred closer to the central feeding station, indicating that predictable feeding sites may influence settlement patterns within populations. Future analyses should reveal the extent to which the use of surplus food confers any fitness benefits in terms of increased reproductive output. From a conservation point of view, this information may improve current guidelines for this conservation strategy and help sustaining healthy populations of scavengers as well as maintaining important ecological and evolutionary processes.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз