Space use during the breeding season of three different forest-dwelling owl species in an area of sympatry: a case study of male hunting home-range sizes and overlaps

Abstract Heterospecific interactions amongst sympatric animals can significantly influence their spatiotemporal behaviours. In birds of prey, ecological relationships such as predation risk or competition for space and/or food may induce mutual spatial avoidance, affecting home ranges’ distribution and sizes. However, studies simultaneously monitoring multiple sympatric owls or diurnal raptors are exceptional. Therefore, we studied four sympatric owls to obtain findings on spatial arrangements of nocturnal/hunting home ranges during the breeding season. Individual males from three of the four studied species (Eurasian Pygmy Owl [ Glaucidium passerinum ], Boreal Owl [ Aegolius funereus ], and Tawny Owl [ Strix aluco ]) were radio-tracked in an area co-inhabited by an apex intraguild predator, Eurasian Eagle-Owl ( Bubo bubo ). The findings revealed a 78% overlap in the hunting ranges of Boreal and Eurasian Pygmy Owls; in contrast, their ranges overlapped only by 25% and 15%, respectively, with that of the Tawny Owl. Further, the Eurasian Eagle-Owl nest site was located within the hunting ranges of both smaller owl males, unlike the Tawny Owl’s home range, which maintained a respectful distance. The Boreal and Eurasian Pygmy Owl males avoided hunting in the Tawny Owl’s home range. In contrast, Tawny Owl male avoided Eurasian Eagle-Owls’ territory, indicating that the subordinate owl species can use the presence of an apex predator to protect themselves from medium-intraguild enemies. Although tentative due to the small sample size, this study offered unique insights into the spatial behaviours of multiple sympatric species. We encourage researchers to implement similar studies, which may provide essential information for conserving threatened species in a rapidly changing environment.