Barn owls eat a variety of vertebrates. Here, most are rodents, such as wood rats, mice or pocket gophers. For a list of all mammals found at Starr Ranch, see here. The adult female will bite off parts for the youngest chicks, but within 7-10 days chicks will rip off bits of prey on their own. By two weeks of age, they’ll consume a whole animal, as long as it is a small enough – such as a mouse.