COMPETITION AT THE CARCASS - OPPORTUNITIES FOR SOCIAL FORAGING BY TURKEY VULTURES IN SOUTHERN ONTARIO

The level of intra- and inter-specific competition experienced by turkey vultures (Cathartes aura) at carrion food patches in southern Ontario was investigated. Despite a diversity of avian and mammalian species directly or indirectly competing with turkey vultures for carrion, only coyotes (Canis latrans) were found to occasionally deplete experimental food patches sufficiently to limit use by turkey vultures. Though American crows (Corvus brachyrhynchos) were the species most commonly observed making use of carrion, their lower food requirements and subordinate status make their competitive impact minimal. In fact, crows appear to inadvertently aid turkey vultures in discovering carrion, since vultures arrived at food patches earlier when crows were already present. Carrion generally lasted long enough for turkey vultures to use roost-centred information transfer as a potential foraging tactic. However, the high degree of intraspecific competition and food patch monopolization by socially dominant individuals limit the presumed benefits for those with the greatest need for food information (i.e., socially subordinate individuals who are inferior foragers). Based upon these findings we suggest that turkey vultures may realize only limited benefits at best from roost-centred food information transfer.