Knowledge Bank

Pellets from common barn owls (Tyto alba) were collected in 1976 and 1979-1981 from seven different locations in Ohio, yielding 14 distinct samples. A total of 12,589 prey items, including 21 mammal species, was identified. The meadow vole (Microtus pennsylvanicus) was 63.9% of all prey and 75.7% of all biomass of mammalian prey. Two species, the meadow vole and short-tailed shrew (Blarina brevicauda), accounted for 84.1% of total prey and 87.8% of biomass of mammalian prey. Birds constituted only 1.5% of total prey. Mean weight of Norway rats (Rattus norvegicus) taken by owls was 59-1 g; the mode was 42.5 g, suggesting selection of small rats since adult rats weigh 200-500 g. Comparison of prey among samples showed a high degree of similarity. The diet of common barn owls can be described as highly stereotyped and restrictive; thus, barn owl foraging behavior should be considered when evaluating habitat requirements and prey resources appropriate for maintenance of barn owl populations.