Strix varia
barred owl

Strix varia is found throughout southwestern Canada, Washington, Oregon and northern California. Its range extends throughout the eastern United States including Florida and Texas. Barred owls have expanded their range into western Canada and the United States during the twentieth century, probably as a result of human modifications of landscapes in those regions.

Strix varia is arboreal, living in coniferous forests near water source, and wooded swamps. They require dense foliage for daytime roosting, and large trees with cavities for nesting. Their reliance on large tree cavities means that populations of barred owls are dependent on the presence of old growth forests throughout much of their range. However, in the Pacific Northwest, where they have been expanding their range in recent years, they readily accept second growth tree cavities. Their close relatives, spotted owls, rely on old growth forests in this region. This has had the effect, in recent years, of increasing the likelihood of interspecific competition in the Pacific Northwest between resident spotted owl populations and new barred owl populations. Some hybridization between the species has also occurred. The overall effect is to stress an already endangered species, spotted owls.

Strix varia is a large, round-headed woodland owl with a grey-white facial disc. Its plumage is grey-brown with buff-white edges and subterminal bars. Barred owls have brown eyes and lack ear tufts. The neck and upper breast have transverse barring and the belly contains vertical brown streaks. Strix varia is dimorphic in body size. Males are 48 cm in length and have a mean weight of 630 g, whereas females are 51cm in length and have an average weight of 800g. The wingspan of Strix varia is between 107 and 111 cm. Juveniles are a red-brown color with buff barring on the neck. Strix varia is a very vocal species with an easily recognizable 9 syllable call; "Who cooks for you? Who cooks for you-all?"

The longest recorded age of a wild barred owl is 18 years and 2 months old. Mortality during the first year of life is probably highest.

Strix varia is primarily a nocturnal hunter, although they have been reported active during the day. Barred owls live alone for most of the year, only living in family groups from the breeding season until the young leave the nest. Mated pairs typically live in adjoining home ranges, with the degree of overlap between home ranges increasing during the breeding season. They will call to other members of the species in the area if disturbed. Barred owls are territorial and do not range widely unless food scarcity causes them to move farther in search of prey. They do not migrate.

Home Range

Estimated home range sizes vary from 273 hectacres (Minnesota) to 1234 hectacres (Saskatchewan). Breeding home ranges tend to be smaller than non-breeding home ranges, from 149 ha (breeding) to 1234 ha (non-breeding) in Saskatchewan.

Barred owls are very vocal species with an easily recognizable 9 syllable call; "Who cooks for you? Who cooks for you-all?", called a two-phrase hoot. Barred owls also communicate with other calls, including the begging calls of nestlings, ascending hoots, and caterwauling, which is typically uttered by mating pairs during duets and occasionally when subduing large prey. Barred owls also probably communicate through some visual signals, through body language.

Barred owls use their keen senses of vision and hearing to detect prey from their perches.

Strix varia individuals are generalist carnivores, feeding on small mammals up to the size of rabbits, birds as large as grouse, reptiles, amphibians, and invertebrates. Barred owls have been observed capturing fish from perches and by wading in shallow water. Without exception Strix varia hunts prey that can be swallowed whole. Hunting is mainly done from a perch. Once prey is spotted, barred owls swoop down upon prey and grab it with sharp talons. Like most owls, barred owls cache prey in tree branches and nests.

Barred owls are preyed on by raccoons and weasels as eggs and nestlings. Adults are sometimes killed by great horned owls, northern goshawks, hit by cars, and captured in traps set for mammals.

Barred owls are important predators of small animals in the ecosystems in which they live.

There are no negative effects of barred owls on humans.

Barred owls feed on small mammals, which helps keep the population of crop damaging rodents under control in rural areas.

Strix varia has been successfully expanding its range in past decades into the Pacific Northwest, where it comes into contact and competition with its close relative, Strix occidentalis, spotted owls. Competition and hybridization between these species stresses the already endangered populations of spotted owls.