engleski

Diet of Wintering Long-Eared Owl (Asio otus) in Osijek, Croatia

This study presents the diet of the long-eared owl (Asio otus) at wintering roosts in Osijek city, in eastern Croatia. The long-eared owl is a strictly protected breeding species in Croatia, which regularly roosts in urban areas during winter. The diet of a wintering long-eared owl was studied using the pellet analysis method. A total of 359 pellets were collected during the winters 2019/2020 and 2020/2021. Collected pellets were stored and frozen at –20°C. Before the separation of bones and hairs, pellets were unfrozen at room temperature and analysed by using the dry technique. The identification of small mammals was done with stereomicroscope (Leica MZ6). Determination keys for small mammals based on skeletal parameters (skulls, lower mandibles, and teeth). Analysed pellets contained remains of 406 specimens belonging to 6 species. The results show that the longeared owl’s prey are small mammals from two families – voles (Microtidae) and mice (Muridae), with species common vole (Microtus arvalis) being the most frequent one and appearing at all sites, on all of the dates, making up more than 65 of the defined species. The abundance of the common vole is followed by the house mouse (Mus musculus) – 12, field vole (Microtus agrestis) – 9 and striped field mouse (Apodemus agrarius) – 7. The rarest species to be found are the bank vole (Myodes glereolus) – 3 and Eurasian harvest mouse Micromys minutus) – 3. The diet composition of long-eared owlreflects small mammals’ fauna in surrounding areas of the Osijek city during winter since diversity of long-eared owl’s prey depends on hunting grounds and seasonal changes. The result of this study confirms the prevalence of common vole (Microtus arvalis) in the diet of the wintering long-eared owl in Osijek city as it was concluded in similar studies of the long-eared owl’s diet in eastern Croatia.

diet composition, pellets, long-eared owl, Asio otus, Osijek, eastern Croatia

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