Guide to North American Birds
Conservation status Much of range is remote from impacts of human activities. In southern parts of range, has probably declined because of habitat loss and disturbance.
Family Owls
Habitat Dense conifer forests, adjacent meadows, bogs. Generally favors country with mix of dense forest for nesting and roosting, and open areas for hunting. In the north, mostly around bogs, clearings, and burns in extensive coniferous woods; in the west, mostly around meadows in mountain forest.
A big nightbird, haunting woods of the far north and certain high mountains of the west. Its great size is partly illusion: it has very thick fluffy plumage, and its body size is smaller than it would appear, so it preys mostly on tiny rodents. When there is a population crash of voles and other rodents in the boreal forest, numbers of Great Gray Owls may drift into the northeast, causing excitement for birders.

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Feeding Behavior

May hunt by day or night. In summer, daytime feeding is usually near dawn or dusk. Usually hunts by listening and watching from a perch, swooping down when it locates prey; sometimes hunts by flying low over open areas. Can locate prey by sound, and will plunge into snow to catch rodents more than a foot below the surface.


Eggs

2-5. White. At times, may lay more eggs in years when food is abundant. Incubation is by female only, 28-36 days. Male brings food to incubating female on nest. Young: Female broods young for first 2-3 weeks. Male brings food to nest, and female feeds it to young. Young may climb out of nest and perch in nest tree or nearby trees after 3-4 weeks, are able to fly 1-2 weeks later. In some areas, adult female departs after young fledge, while male remains with them and feeds them for up to 3 months.


Young

Female broods young for first 2-3 weeks. Male brings food to nest, and female feeds it to young. Young may climb out of nest and perch in nest tree or nearby trees after 3-4 weeks, are able to fly 1-2 weeks later. In some areas, adult female departs after young fledge, while male remains with them and feeds them for up to 3 months.

Diet

Mostly small mammals. Feeds mainly on voles in many northern areas; in western United States, pocket gophers may be main prey. Also eats mice, shrews, squirrels, weasels, small birds, rarely frogs.


Nesting

In courtship, male may feed female; members of pair preen each others' feathers. Nest: Usually uses old abandoned nest of other large bird, such as goshawk, raven, Osprey; sometimes nests on top of broken-off snag or stump, rarely on the ground. Site usually 10-50' above ground. A pair may reuse the same nest for several years.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

No regular migration, but nomadic. Large numbers may move south or southeast in some winters in eastern Canada and extreme northeastern United States; this is apparently in response to a sudden drop in rodent populations.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

See a fully interactive migration map for over 450 bird species on the Bird Migration Explorer.

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Songs and Calls

Very deep, booming whoo, repeated 10 times or more, and gradually descending the scale.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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