The long-eared owl (Asio otus) and short-eared owl (A. flammeus) are indistinguishable by bone morphology alone. Since they inhabit contrasting ecological situations, identification of their bones from prehistoric sites is important for paleoenvironmental interpretations. Measurements on long bones of modern specimens indicate these species can be identified by bone size. Tables are presented for use by the analyst in identifying complete or fragmentary wing and leg bones.