Other major prey include gophers, rabbits and hares. Summer diets are more varied with deer mice and voles being important foods. Spotted Owls are known to capture 30 mammal species including bats, and 23 bird species as prey. They also eat snakes, crickets, beetles, and moths. They have been known to walk around campgrounds at night to pick up scraps of food.
Pellets contain numerous bones, skulls, and teeth, and are held together by fur and mucus.
Timing and success in producing offspring are strongly linked to the availability of prey, and not all pairs breed every year. Spotted owl pairs mate for life, but a new mate is readily taken if the other disappears. They probably begin breeding at two to three years of age. Spotted Owls nest primarily in stick nests of Northern Goshawks, on clumps of mistletoe, in large tree cavities, on broken tops of large trees, on large branches, or cavities in banks and rock faces. Old nests are not repaired before eggs are laid, and tend to be reused year after year.