The Barn Owl (Tyto alba) is distributed world-wide, absent from only the cold Latitudes. While the barn owl is found all over the US, its numbers are particularly high in California and the Southwest. Farmers and ranchers are increasingly attracted to the barn owl's ability to control rodents better than traps, poison, or cats and at very little cost.

Barn owls in favorable habitats produce large broods once or twice a year. Each young owl as it nears maturity will eat the equivalent of a dozen mice per night if such prey is available. Adult barn owls kill and consume the equivalent of one large rat or gopher per night. The Owl Rehabilitation Research Foundation, Ontario, Canada, reports that barn owls consume twice as much food for their weight as other owls. A family of barn owls will eat about 3,000 rodents a year, with about 70% gophers. Refined wing and feather structures make it silent in flight, bringing its well- deserved nickname "the cat with wings."

Both prey base (rodents) and suitable nesting sites limit the number of barn owls in an area. Owl nest boxes can be within 30 feet of each other. In the West, barn owls nest in natural tree cavities and buildings, as well as in cavities in cliffs and cut banks, stacked hay bales, and in palm trees. Use of these sites often leads to nesting failure such as when bales are shifted or the young outgrows the nest at the base of palm fronds. They are accustomed to humans and will tolerate a moderate level of activity as long as they are not threatened.

Several nest box designs can be made from inexpensive or recycled materials. In California it is best to install nest boxes in December, but since they have several broods a year, anytime early in the year may bring an occupant. Owls seek their prey either from a perched position or on the wing. Perches in areas with high rodent populations aid the owl’s search.