PREDATION OF BIRDS AT FEEDERS IN WINTER

A continentwide survey of homes with bird Feeders produced 567 reports documenting 1138 incidents of predation. Of the 25 species of predato rs recorded, three (Sharp-shinned Hawk, Accipiter striatus; domestic c at; Cooper's Hawk, A cooperii) were responsible for 80% of the inciden ts in which the predator was known. Ten of the 62 species of prey iden tified accounted for 32% of all victims. The birds most vulnerable to predation were those that commonly occur at feeders throughout the con tinent (i.e., the most widespread species), but additionally, flocking species were more vulnerable to avian predators than more solitary on es. Prey size was correlated to size of avian predators, but cats conc entrated on small birds. Hawks were attracted to feeders with particul arly high levels of bird activity, but cats were not. The bird-feeding environment does not appear to expose birds to a higher risk of preda tion than is encountered in the absence of feeders.