Great gray owl, Phantom of the North, Cinereous owl, Spectral owl, Lapland owl, Spruce owl, Bearded owl, Sooty owl
The Great grey owl (Strix nebulosa) (also Great gray owl in American English) is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in the genus Strix found in both the Eastern and Western Hemispheres. In some areas, it is also called Phantom of the North, cinereous owl, spectral owl, Lapland owl, spruce owl, bearded owl, and sooty owl.
Adult Great grey owls have large rounded heads with grey faces and yellow eyes with darker circles around them. The underparts are light with dark streaks; the upper parts are grey with pale bars. These owls do not have ear tufts and have the largest facial disc of any raptor. There is a white collar or "bow tie" just below the beak. The long tail tapers to a rounded end. The males are usually smaller than the females, as with most owl species.
Great grey owls breed in North America from as far east as Quebec to the Pacific coast and Alaska and from Finland and Estonia across northern Asia. They are permanent residents, although northerly populations may move south and southeast when food is scarce. In Europe, they are found breeding in Norway and Sweden and more numerously through Finland and Russia. In northern areas, Great grey owls prefer to breed in the dense coniferous forests of the taiga, near open areas, such as meadows or bogs. In Oregon and California, they may nest in mixed oak woodlands.
Great grey owls are generally solitary birds and outside of the breeding season prefer to spend their time singly. They are very powerful hunters that wait, listen, and watch for prey, then swoop down; they also may fly low through open areas in search of prey. They frequently hunt from a low listening post which can be a stump, low tree limb, fence post, or road sign. Their large facial disks, also known as "ruffs", focus sound, and the asymmetrical placement of their ears assists them in locating prey, because of the lack of light during the late and early hours in which they hunt. On the nesting grounds, Great grey owls mainly hunt at night and near dawn and dusk; at other times, they are active mostly during the night. Great grey owls are not as aggressive as most other alpha predators. They are less likely to attack each other or potential threats than other large predatory birds. They do not protect a large nesting territory, nor do they defend hunting territories through aggression. As an exception, the female is aggressive in protecting eggs and owlets. She is especially alert and aggressive when fledglings first leave the nest but cannot yet fly, and thus are extremely vulnerable. Great grey owls communicate with a series of very deep, rhythmic 'whoos', which are usually given in correlation to their territories or in interactions with their owlets. At other times, adults are normally silent. The young may chatter, shriek, or hiss.
Great grey owls are carnivores and rely almost fully upon small rodents. What species they eat depends on which small mammals are most abundant and available. These include lemmings, pocket gophers, voles, hares, moles, shrews, weasels, thrushes, grouse, Canada jays, mountain quail, small hawks, and ducks.
Great grey owls are monogamous and form pairs. Nesting usually occurs from March to May. They do not build nests, so they typically use nests previously used by a large bird, such as a raptor. They will also nest in broken-topped trees and cavities in large trees. The female typically lays 4 eggs and incubates them for 28 to 36 days. Owlets hatch blind and helpless. Brooding lasts 2 to 3 weeks, after which the female starts roosting on a tree near nests. The young jump or fall from the nest at 3 to 4 weeks, and start to fly 1 to 2 weeks after this. Immediately after fledging, the white, fuzzy owlets must use beaks and feet to climb back into trees. The female is on guard at this time and may be aggressive toward potential predators. Most owlets remain near their natal sites for many months after fledging. Normally the male hunts for his mate and the young throughout the nesting period. Once the owlets begin the fly, the female typically withdraws and the male continues to feed the young until they can hunt on their own in the autumn. The young owls go off on their own by winter.
The harvest of timber from the Great grey owl's habitat is, perhaps, the greatest threat to this species. Intensified timber management typically reduces live and dead large-diameter trees used for nesting, leaning trees used by juveniles for roosting before they can fly, and dense canopy closures in stands used by juveniles for cover and protection. If perches are not left in clear-cuts, Great grey owls cannot readily hunt in them. Although human-made structures (made specifically for use by this species) have been utilized by these owls, the species is far more common in areas protected from logging. Livestock grazing in meadows also adversely affects Great grey owls, by reducing habitat for preferred prey species. Other dangers to these birds include rodenticides, and collisions with vehicles.
According to the IUCN Red List, the total population size of the Great grey owl is 50,000-99,999 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.
