Western screech-owls eat mostly small mammals and large insects. Their diet varies with habitat and region. It includes many beetles, moths, other insects, as well as spiders, scorpions, centipedes; also many small mammals, such as mice, voles, pocket gophers. Screech-owls also eat small birds, lizards, snakes, frogs, and fish.
Their lifespan can be up to 13 years in the wild and up to 20 years in captivity.