Unique among small owls with entirely dark eyes. Finely vermiculated gray plumage looks stained with bits of rust. Surprisingly common in montane forest dominated by pine, often mixed with aspen; one survey in Utah found 47 calling individuals along just five miles of road! Strictly nocturnal; most easily detected when singing low, muffled hoots. Feeds mostly on insects. Highly migratory; moves southward into Mexico for the winter.