Habitat[edit]
In northern areas their breeding habitat is often the dense coniferous forests of the taiga, near open areas, such as meadows or bogs. In Oregon and California this owl has been found nesting in mixed oak woodlands. Once believed to require a cold climate, it is now known that this bird survives in a few areas where summer temperatures regularly exceed 100 °F (38 °C).

Range[edit]
They breed in North America from as far east as Quebec[2] 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. Even though the species occurs in Europe, the first great grey owl recognized by science was found in Canada in the late 18th century.

 
Adult female
There are sedentary populations in the Pacific states of California, Oregon, and Washington. The great grey owl in this region is found in disjunct areas of appropriate habitat. In winter these birds do not move far but may go downslope to escape deep snow as they must capture their prey on the ground.

In Oregon, the great grey owl breeding range is scattered from the Siskiyou Mountains in the southwest to the Blue Mountains in the northeast. Two bird festivals each May feature field trips to try to see the species: the Ladd Marsh Festival in La Grande, OR and the Mountain Bird Festival in Ashland, OR.

A 2015 study in California estimated there were fewer than 300 birds in the state at the time. The species is listed as Endangered under the California Endangered Species Act.[7] The California range for the species includes a small extension of the Oregon population, north of Alturas. In addition breeding has been confirmed in the Tahoe National Forest east of Nevada City; in the Sierra Nevada foothills south of I-80 at around 2,000 feet (610 m) elevation; and for the population clustered around Yosemite. In Yosemite is where the first nest south of Canada was found in 1914. A study of the Yosemite owls shows that this population has been genetically isolated from populations in Oregon and farther north for over 25,000 years. Biologists working on that study suggest that the Yosemite population should be considered a separate sub-species. Nearby populations at lower elevations were not tested.

Range[edit]
They breed in North America from as far east as Quebec[2] 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. Even though the species occurs in Europe, the first great grey owl recognized by science was found in Canada in the late 18th century.

 
Adult female
There are sedentary populations in the Pacific states of California, Oregon, and Washington. The great grey owl in this region is found in disjunct areas of appropriate habitat. In winter these birds do not move far but may go downslope to escape deep snow as they must capture their prey on the ground.

In Oregon, the great grey owl breeding range is scattered from the Siskiyou Mountains in the southwest to the Blue Mountains in the northeast. Two bird festivals each May feature field trips to try to see the species: the Ladd Marsh Festival in La Grande, OR and the Mountain Bird Festival in Ashland, OR.

A 2015 study in California estimated there were fewer than 300 birds in the state at the time. The species is listed as Endangered under the California Endangered Species Act.[7] The California range for the species includes a small extension of the Oregon population, north of Alturas. In addition breeding has been confirmed in the Tahoe National Forest east of Nevada City; in the Sierra Nevada foothills south of I-80 at around 2,000 feet (610 m) elevation; and for the population clustered around Yosemite. In Yosemite is where the first nest south of Canada was found in 1914. A study of the Yosemite owls shows that this population has been genetically isolated from populations in Oregon and farther north for over 25,000 years. Biologists working on that study suggest that the Yosemite population should be considered a separate sub-species. Nearby populations at lower elevations were not tested.

The harvest of timber from the great grey owl's habitat is, perhaps, the greatest threat to this species.[9] 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.[9] If perches are not left in clearcuts, 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.[9]

 
Plumage of the face (Weltvogelpark Walsrode)
 
Other dangers to great grey owls include rodenticides, collisions with vehicles, and West Nile Virus. West Nile Virus is likely to become more prevalent with climate change. In Ontario and northeastern Oregon there are confirmed great grey owl deaths from West Nile Virus. Testing of owls in the Yosemite area since 2005 has found evidence of West Nile Virus in that population.

Due to their large size, great grey owls have few natural predators. Great horned owls, various small carnivores, and black bears have been documented preying on young, but such predators rarely threaten adults, and owls have been known to fend off animals as large as black bears when defending their nests.[10] The only known predator of adult great grey owls is the Eurasian eagle-owl (Bubo bubo), which occasionally preys on the former in parts of Europe.[11

Territorial behavior[edit]
The great grey owl is not as aggressive as most other alpha predators. They are less likely to attack each other or potential threats than are 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.

This lack of territorial aggressiveness makes the great grey owl difficult to find in the field. Most owls respond to their own species calls if played back in a nesting territory. Great grey owls will often ignore such calls. They also do not flush every time a human approaches or drives past. The great grey owl often remains still even if a human is nearby and therefore they are often overlooked or unnoticed.

Provincial bird[edit]