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The aim of the present work was to compare the prey species spectrum of three species of owls that co-occur in the mosaic environment of Silesian Lowland (SW Poland). The material for the study - the pellets - was collected at three sites in winter 2000/2001. The localities were: Chomiąża (church), the wintering site of barn owl Tyto alba, Owieczki (unused barn) - tawny owl Strix aluco, and Środa Śląska (park) - long-eared owl Asio otus. The aerial distance between the localities is: Chomiąża - Środa Śląska - 4 km, Chomiąża - Owieczki - 10 km, Środa Śląska - Owieczki - 6 km. The remains of 914 prey individuals were found in the pellets. Eighteen species of mammals of four orders were identified: Insectivora, Rodentia, Chiroptera, Carnivora and six species of passerine birds (Passeriformes). The species spectra of prey of barn owl and the long-eared owl are similar. However, the long- -eared owl specializes in small rodents and the barn owl includes also shrews Soricidae among its prey. The diet of the tawny owl is more diverse. It hunts for rodents and insectivorous mammals and birds. The feeding preferences are reflected not only in the species spectrum of prey but also in the biomass of the consumed food. According to the biomass analysis, the rodents make the basic food of the three species of owls. The analysis of the ecological groups of owls' prey living in various biotopes showed that 50% of the tawny owl prey were caught in the forest. The percentage of forest rodent species in the diet of the barn owl and the long-eared owl are very low. The tawny owl hunts also in open, wet and boggy habitats. Such biotopes are sometimes searched by the long-eared owl and the barn owl rarely flies there. The rodent species associated with open fields make the main part of the barn owl diet. The species spectra of the owls' prey in the studied area show that the food niches of barn owl and the long-eared owl overlap. The tawny owl exploits a separate food niche from the niches of the other owl species. The presence of weasel among the prey of the long-eared owl is reported here for the first time in Polish literature. [ABSTRACT FROM AUTHOR]

The aim of the present work was to fill out some gaps in the knowledge of Micromammalia of Racibórz Basin (South Poland). This area is one of the most poorly studied as far as mammals of Poland are concerned. Until now, 18 species of small mammals were recorded, including six species recorded for the first time in the present work. The species of mammals were identified basing on the remains found in the pellets collected in church towers for the project ‟The role of sacral buildings in conservation of the barn owl Tyto alba„. There were 197 pellets collected at three localities: Pietrowice Wielkie, Lubowice, and Racibórz, in 2000. Remains of 485 vertebrate individuals were found in the collected pellets. Of these 98.8% were mammal prey and 1.2% were birds. Among mammals 13 species were identified. Common vole Microtus arvalis predominated among mammalian prey. [ABSTRACT FROM AUTHOR]