Dynamic interactions at birdfeeders: Attracting both prey and predators across urban and rural habitats

Abstract

Winter is a critical period for the survival of local bird species in temperate regions. Some wintering birds may rely on transient food, such as that provided at birdfeeders, but bird communities around birdfeeders may also attract predators. However, these effects of birdfeeders on interspecific interactions between birds and their predators remain largely unexplored and have so far not been tested experimentally. We hypothesized that birdfeeders indirectly attract predators in winter because of the attraction of small birds, and tested this hypothesis using experimental feeders at 52 different urban and rural sites across western Poland. We found that the number of small birds increased around birdfeeders, particularly those with provided food. We found that birdfeeders that attracted more small birds (regardless of whether they provided food) attracted also more predators, such as sparrowhawks Accipiter nisus and feral cats Felis domesticus. Moreover, birdfeeders in urban habitats attracted relatively fewer small birds but not fewer predators compared to those in rural areas. Altogether, birdfeeders with food provided attracted small prey birds but they attracted also more predators, whose presence may hinder small birds from fully utilizing available resources, potentially impacting their winter survival through direct (mortality) and indirect (increased monitoring and vigilance) effects.