Carcasses increase the probability of predation of ground-nesting birds: a caveat regarding the conservation value of vulture restaurants

Carcasses not only recruit carrion-eaters, but can also attract facultative scavengers which could predate on species living in the surroundings. At supplementary feeding stations ('vulture restaurants') carcasses are available permanently, posing a conservation dilemma: enhancing populations of endangered scavengers might introduce a predation pressure on non-target species. Here, we test if nest predation risk on ground-nesting birds increases near carcasses in Fuerteventura Island (Canary Archipelago). This is an optimal scenario for performing this study because there is a simple community of ground-nesting birds and facultative scavengers; carrion-eaters feed regularly in a unique vulture restaurant but also exploit scattered carcasses of goats. We placed artificial nests along different lines located at variable distances (200 m to 34 km) from the vulture restaurant or from single carcasses. Sixty-seven per cent of lines and up to 90% of nests within lines were predated. Predation risk was higher in lines near carcasses, that is single carcasses or the vulture restaurant. Thus, our study alerts that choosing the location for vulture restaurants may be the key not only for scavengers but also for the conservation of the species living nearby.