Barn and Long-Eared Owl Diets: A Comparative Study from Central Pennsylvannia and a Key for Identification of Prey Items

Abstract

Two sympatric owl species, Tyto alba (Barn Owl) and Asio otus (Longeared Owl), are found in Lewisburg, PA. These species are of similar size, have similar hunting styles, and most likely use similar prey items. In studying the diets of these two owl species, we were able to determine their prey selection, the types and relative abundance of prey in the area, and how these sympatric predators may be partitioning their resources. A total of 80 pellets (40 from Barn Owls and 40 from Long-eared Owls) were analyzed to understand their diets. Pellets were collected from two locations in Lewisburg, PA approximately 2 km apart. Cranial and postcranial remains within the owl pellets were used to identify species by comparing them against our reference collections and keys. Typically, the Barn Owl is present in Lewisburg from late spring through fall and the Long-eared Owl from late fall through spring. Barn Owl pellets contained a greater number of larger-sized prey than Long-eared Owl pellets. Both owl species rely heavily upon rodents as their primary food source, which make up over 90% of their diets. Temporal differences and differences in prey selectivity are most likely the major factors allowing these species to share their common resources.