Diverse foraging strategies of an avian apex predator in an old-growth forest.

Organisms aim to maximize their energy intake while minimizing the energy expended during foraging. However, as the environmental conditions vary in space and time, they have to adjust foraging strategies accordingly. The Eurasian Goshawk (Astur gentilis) is an iconic bird of prey widely regarded as a sentinel species of valuable old-growth forests. However, as a flexible raptor, it also thrives in other landscape types, such as agricultural and urban environments. We used GPS telemetry to track the movements of 13 male Goshawks breeding in the largest remaining temperate lowland old-growth forest in Europe, the Białowieża Forest, and examined their diet and reproductive success. We detected a variety of foraging strategies among individuals, ranging from predominantly forest-based hunting to regular excursions outside the forest to forage in farmland, villages, and towns. These behavioural responses were not consistently associated with nest site locations and consequently we found no relationship between home range size and either forest quality in the nest surroundings or proximity to alternative foraging habitats. Strikingly, several individuals breeding deep within the forest routinely travelled up to 20 km to hunt feral pigeons in a town, suggesting that the high abundance, accessibility, and predictability of optimal prey in urban environments shape the foraging behaviour of raptors even within primeval forests. We conclude that, rather than a single optimal foraging strategy, several equally profitable strategies exist for Goshawks breeding in old-growth forests.