Scientific Annals of the Danube Delta Institute (Oct 2008)
The diet of wintering Barn Owls (Tyto alba) in the region of Histria, the Danube Delta Biosphere Reserve
Abstract
The Barn Owl (Tyto alba) is a common nocturnal predator of agro-ecosystems and it is widely distributed, especially in European countryside. The species uses human artifacts, ruins, barns, attics, towers for breeding and roosting, these sites can provide researchers with hundreds of pellets, thus its diet is well known. A first assessment of the diet and food selection was made for the southern part of the Danube Delta Biosphere Reserve in the wintering period, in a unique wetland-grassland complex, with large areas of steppes. Mammals dominated the diet spectrum, with the shrews (Soricidae) being the most frequent (48.3%), followed by the mice (Muridae), and the voles (Arvicolinae). The mammalian component of the diet is important also in terms of biomass (97.8 %). The most valuable species is the Sibling Vole (Microtus epiroticus) equalling 25.5 % of all biomass consumed, followed by the Common White-toothed Shrew (Crocidura suaveolens) and the Mound-building Mouse (Mus spicilegus). Birds and amphibians made up a small portion of the diet, both in terms of occurrence and of biomass. Three species of birds were captured, the House Sparrow (Passer domesticus) being the most important. The results suggest that the Barn Owl is a specialized feeder relying on small mammals and completing its diet with other prey only occasionally.
