Interaction between the White-tailed Eagle and Common Buzzard estimated by diet analysis and brood defence behaviour

Abstract

Recent evidence suggests that the White-tailed Eagle (Haliaeetus albicilla) – the largest avian predator to have recently recovered in Europe – may prey on mesopredators and their broods. Mesopredators may respond to predators near their nests by exhibiting offspring defence behaviour. The present study involved White-tailed Eagle diet analysis, and we report on their predation on Common Buzzard (Buteo buteo) nestlings and the results of a field experiment conducted near the nests of Common Buzzards to test how they respond to the appearance of a top predator. The remains of nestling Common Buzzards were observed in 9% of successful nests, while evidence on the consumption of other raptor species was scarce. Additionally, our results indicate that habitat and pair/territory identity may explain the probability of predation on mesopredators, thus suggesting a spatially varying effect on smaller raptors.