These distinctive birds of prey are divided by structural differences into two families, the Barn Owls (Tytonidae) and the Typical Owls (Strigidae). All have immobile eyes in large heads. Fluffy plumage makes their flight nearly soundless. Many species hunt at night and roost during the day. Hooked bills, hooked claws, and usually feathered feet (outer toe reversible). Some species have conspicuous feather tufts. Food: Rodents, birds, reptiles, fish, large insects. Range: Nearly cosmopolitan. Number of species: World: 134 (Barn Owls, 11; other owls, 123); West, 18. To find an owl, search the ground for regurgitated pellets of fur and bone below a nest or roost. Listen for flocks of small songbirds noisily mobbing a roosting owl.