Eurasian eagle-owl Bubo bubo (Linnaeus, 1758) (Aves: Strigidae) in Eastern Serbia in the 21st century: Distribution, population size and density

The Eurasian Eagle-owl represents a widely distributed but locally scarce apex predator whose biology and ecology in Serbia remain understudied. Here, we examined the spatial and altitudinal distribution, population size, and territory density of this species in Eastern Serbia. Our surveys identified 79 owl territories spread across 51 10×10 km UTM squares, resulting in a mean density of 0.5 territories/100 km². The territories were unevenly distributed, primarily concentrated in hilly terrains, river valleys and along mountain edges. The altitudinal range of identified territories spanned from 65 to 645 m, with the majority located in hilly zones below 500 m. Notably, we discovered 42 new, previously undocumented territories. Based on the collected data and habitat modelling, we estimate that the number of Eagle-owl territories in Eastern Serbia ranges from 135 to 170. Our findings contribute to a better understanding of the species' ecology and form a solid framework for future studies.