California Raptor Center

Great Grey Owl

Scientific Name: Strix nebulosa
(Strix is Latin for ‘screech owl’, nebulosa is Latin for ‘cloudy’ which is a reference to feather color ‘dingy light and dark gray’)

Size: Length: 24-33in Wingspan: 54-60in

Weight: Female: 1144-1454g (~2.5-3.2lb) Male: 790-1030g (~1.7-2.3lb)

Lifespan: In the wild the average is 13-15 years and in captivity may live around 40 years.

ID: One of the World's largest Owls, dark grey overall interspersed with bars and flecks of light grey and white. When perched, they appear very bulky because of their dense, fluffy plumage, long wings extending past the body, a relatively long tail, and a large head. The size of the head, and the prominent facial disk make the yellow eyes appear small. A noticeable white "moustache" strip is under the facial disk, broken by a black "bow-tie". The feet are heavily feathered and remain hidden from view.

Hunting: The Great Gray Owl hunts mainly during early morning and late afternoon, especially during winter, but will also hunt during other daylight hours and at night. They are often seen perched on poles or fence posts along roads. When hunting, a Great Gray Owl will use a perch to "sit and wait" or it may hunt through the forest a few feet above the ground. When ground is covered with snow, a Great Gray Owl can hunt by hearing alone and often plunges into the snow as far as 12in.

Prey: Although a very large owl, small rodents are their primary prey. Birds are rarely eaten, but will include crows, small hawks, American Robin, ducks and grouse. Frogs, toads, snakes, and insects are also eaten infrequently.

Breeding: The male selects possible nest sites and attracts its mate with calls. Several sites are inspected before she chooses the nest site. Nests primarily in stick nests made by hawks, ravens, or crows, in the hollowed out top of large-diameter snags, or on the top of clumps of mistletoe, and in Europe sometimes on the forest floor. Northern Goshawks are very common providers of nest sites for Great Gray Owls. They also use artificial platforms or nests placed in suitable habitat. Nests are usually in a forest, but with a large clearing or meadow located within 1.3km (0.8 miles). Unlike most other Owls, nests are usually tidied up and refurbished before use. Nest linings include conifer needles, deer hair, moss, and shredded bark. 2 to 5 (average 3) eggs are laid, each separated by 1 to 2 days. Incubation commences with the first egg laid and lasts 28 to 29 days. The female does all incubation and the male provides all food to the female and young. Young leave the nest at 3 to 4 weeks. Fledging occurs after about 8 weeks and young remain near the nest for several months, with the female caring for them.

Range: Great Gray Owls are semi-nomadic, with irregular site or mate fidelity between years. They tend to settle and nest in areas with high food resources and this may lead them to occupy the same nest for several years or move off to new areas. Nesting territories are defended from other Great Gray Owls, but foraging areas are widely overlapping. Great Gray Owls are found from Alaska across Canada, down the Northern Rocky Mountains, and northern Minnesota. They are also found in northern Europe and Asia.

Status: The U. S. Department of Interior Bureau of Land Management considers Great Grays to be a sensitive species, and is protected in the United States on both federal and state levels.