Different alternative diets within two subgroups in a winter roost of long-eared owls

Filip Tulis 1 , Tomáš Veselovský 2 ,  and Simon Birrer 3
  • 1 Department of Environmental Sciences, Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, 949 01, Nitra, Slovakia
  • 2 , Raptor Protection of Slovakia, 841 01, Bratislava, Slovakia
  • 3 Swiss Ornithological Institute, , 6204, Sempach

Abstract

In winter 2013/2014 a roost of long-eared owls in Bojnice Spa (central Slovakia) was formed by two subgroups situated 12 meters apart from each other. The diets of both subgroups and the direction of the owls’ departure from the roost were studied at monthly intervals. Owls of the Pinus-subgroup left the roost in a significantly different direction compared with the owls in the Picea-subgroup. The common vole was the most hunted prey in both subgroups. However, comparing the alternative prey of the two subgroups, the wood mouse and other mammals were found significantly more often in pellets of the Picea-sub-group, whereas birds were more frequent in pellets of the Pinus-subgroup. Our results suggest that the different prey hunted by the two subgroups may be a consequence of diverging hunting areas with different availability of alternative prey species.

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