Managing supplementary feeding for avian scavengers: Guidelines for optimal design using ecological criteria

Current European sanitary laws are promoting the concentration of domestic livestock carcasses in lim- ited locations called ‘vulture restaurants’ or supplementary feeding stations in order to safeguard human health. However, this type of food concentration could lead to monopolization by a few, large dominant species. Management guidelines are urgently needed to ensure that potentially less competitive and more endangered scavengers can also benefit from this resource, considering that once abundant car- casses are now absent from the field. Here, we assess factors affecting the abundance of six avian scav- enger species at 17 feeding stations in northern Spain, considering aspects such as carrion availability, physiographic features, humanization, presence of heterospecifics and densities of scavengers during both winter and summer seasons. Results indicate that conditions for interspecific facilitatory processes are possible at low numbers (<100 individuals) of griffon vultures (Gyps fulvus). Otherwise, the other avian scavengers are excluded. In a few cases, spatio-temporal patterns of segregation become apparent. Differences in the size of carcasses supplied to feeding stations as well as the local characteristics influ- ence the balance of species at these points and, therefore, how species of conservation concern use feed- ing stations. Future legislation should encourage the opening of numerous feeding stations supplied with low quantities of food to mimic the original condition of temporal and spatial unpredictability of car- casses and to maintain ecological relationships within the scavenger guild.

Peer reviewed