A contribution to the knowledge of diet composition of the Barn Owl Tyto alba in the area of Pisa (Italy)

Abstract We examined the pellets of the Barn Owl Tyto alba, collected in Pisa, Italy, in 2012. Altogether, 219 specimens of small mammals were found in 85 pellets. The Barn Owl diet was composed of ten species of small mammals, representing three different families (Muridae, Cricetidae, Soricidae). The main prey species was the Wood Mouse Apodemus sylvaticus, followed by the House Mouse Mus musculus and the Savi’s Pine Vole Microtus savii. While the smallest of the small mammals from the area, the Etruscan Shrew Suncus etruscus, was well represented in the pellets, some larger species of small mammals were not represented at all. The reason for such result may lie in the upper limit for our Barn Owl’s prey size. Results suggest that optimal prey weight for our Barn Owl may be between 26–75 g of body mass, however, the prey can be occasionally as heavy as almost 100 g, represented by adult Rat Rattus spp. Nevertheless, our results may not reflect the true hunting strategy of the Barn Owl, but the availability of a certain food item at one point in time.