Silent predators that seek out their game mostly at night, owls consume living prey suited to the size of the owl. Built to hunt, owls have good eyesight and hearing, sound-muffling feathers, hooked beaks and sharp claws. Over 200 species of owls range from sparrow- to eagle-sized birds. Owls eat insects, spiders, scorpions, other invertebrates, reptiles, amphibians, fish, birds and mammals such as mice and rats. You can tell what many owls eat by identifying bones, fur, feathers and insect parts contained in regurgitated owl pellets.

Small owls usually include insects and other invertebrates in their diet. Eastern screech owls in Kentucky ate crayfish and beetles along with shrews, voles, mice and birds. Sparrow-sized elf owls capture scorpions, centipedes, crickets, moths and beetles. Some small owls can capture and eat birds as large as themselves, however.

Most larger owls eat a wide variety of prey. According to the World Owl Trust, owls are opportunists and will eat whatever they find. Great horned owls, common in North and South America, eat skunks, raccoons, squirrels, falcons, other owls and even dogs and cats. Common throughout the United States and in Europe, barn owls eat primarily rodents but also shrews, bats and rabbits and birds. The largest owls, such as eagle owls of Eurasia, prey on golden eagles and deer weighing 28 pounds. Asian fish owls and African fishing owls eat fish, aquatic invertebrates and amphibians.