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Great Gray Owl

Strix nebulosa ORDER: STRIGIFORMES FAMILY: STRIGIDAE

IUCN Conservation Status: Least Concern

The Great Gray Owl is a dapper owl dressed in a gray suit with a bow tie across its neck and a surprised look on its face. In the stillness of a cold mountain meadow the elusive giant quietly floats on broad wings across meadows and openings in evergreen forests. They are mostly owls of the boreal forest with small populations in western mountains, but in some years they move farther south in search of food, giving some a unique opportunity to see this majestic owl.

At a GlanceHelp

Measurements
Both Sexes
Length
24–33.1 in
61–84 cm
Wingspan
53.9–60.2 in
137–153 cm
Weight
24.7–60 oz
700–1700 g
Relative Size
Larger than a Great Horned Owl in size, but not in weight. Smaller than a Bald Eagle.
Other Names
  • Chouette lapone (French)
  • Cárabo lapòn (Spanish)

Cool Facts

  • Although the Great Gray Owl is one of the tallest owls in the U.S., it’s just a ball of feathers. Both the Great Horned Owl and Snowy Owl weigh more than a Great Gray Owl and they have larger feet and talons.
  • Imagine what it would be like if you could hear even the slightest noise and knew exactly where the noise was coming from. Well, that is exactly what Great Gray Owls can do. Like the Barn Owl and Long-eared Owl they have asymmetrical ear openings that help them find prey by sound alone. The left ear opening is higher on the head than the right ear opening which enables precise directional hearing and lets them nab invisible prey.
  • Great Gray Owls aren’t just North American owls. They also live in Scandinavia, Russia, Siberia, and Mongolia.
  • Great Gray Owls are powerful birds. Despite weighing only 2.5 pounds, they can break through hard packed snow to grab a small mammal. One bird reportedly broke through snow that was hard enough to support a 176-pound human.
  • Great Gray Owls are big owls, which means that they need to eat regularly. In the winter, they eat up to 7 vole-sized small mammals every day.
  • Both the common and scientific names are apt for this large gray owl. The Latin name for Great Gray Owl is Strix nebulosa. Strix means to utter shrill sounds and nebulosa means misty or cloudy, referring to its gray color.
  • The oldest recorded Great Gray Owl was at least 18 years, 9 months old and lived in Alberta, where it was banded in 1996 and found in 2013, after being hit by a car.

Habitat


Forest

In Canada, Great Grays spend the year in dense, wet evergreen forests of the far north, also known as taiga, where they hunt in meadows, bogs, or other open areas with a few scattered trees. In the United States, they use pine and fir forests adjacent to montane meadows between 2,500 and 7,500 feet. In California and Oregon during the winter months, owls often move downslope into oak woodlands and lower elevation mixed deciduous and evergreen forests.

Food


Mammals

Small mammals such as voles, pocket gophers, mice, moles, chipmunks, and lemmings make up the majority of their diet. They hunt at night and during the day from perches where they listen intently for small mammals moving under the snow. Once they detect a small mammal they hover above the snow, and plunge talons first into the snow to grab it.

Nesting

Nesting Facts
Clutch Size
2–5 eggs
Number of Broods
1 broods
Egg Length
2.1–2.1 in
5.3–5.4 cm
Egg Width
1.7–1.7 in
4.2–4.3 cm
Incubation Period
28–36 days
Nestling Period
26–29 days
Egg Description
Dull white and unmarked.
Condition at Hatching
Helpless, eyes closed, completely covered in fluffy down.
Nest Description

Great Gray Owls don’t build nests. Instead they use old raptor or Common Raven nests, or even nests built by western gray squirrels, and do not add any additional material to the nest. They also place their eggs in the broken tops of dead trees, human-made platforms, or in clumps of mistletoe. If they nest in a broken-topped tree, the female may scratch a depression to lay the eggs, but she does not build a nest. The location where they lay their eggs varies depending on the nest site they chose to use.

Nest Placement

Tree

These owls often choose a nest site near an opening in the forest, such as a meadow, bog, or field. The adults may visit a potential nest site two or more weeks before they settle on it. They often reuse the same nest site for several years.

Behavior


Aerial Dive

Great Gray Owls are active at night and at dusk and dawn. They also hunt during the day, especially when they have nestlings or during the winter months. They forage in meadows where voles and other small mammals are abundant. In northern Europe, the Rocky Mountains, and the central Cascades of Oregon they also forage in clearcuts that have a few remaining trees for perching. They glide low over these open areas with slow and quiet wingbeats listening and looking for small mammals. They have excellent hearing and can find prey by hearing alone—even under a thick cover of snow—thanks to asymmetrical ear openings that help them triangulate sound with great precision. Males and females form pairs during the breeding season, but they don’t stay together during the nonbreeding season. Males and females defend their nest sites from other owls and raptors. The first line of defense is a threatening display. They spread their facial feathers to expose their bill, which they fiercely snap, drop their wings, or hoot to shun the intruder. If that doesn’t work, they may escalate territory defense to chasing and sometimes attacking the intruder. Most owls are year-round residents, but sometimes they move farther south in search of food. Populations in California and Oregon, in most winters, move to lower elevations areas with reduced snowpack.

Conservation

status via IUCN

Least Concern

The Great Gray Owl’s far northern range and elusive habits make it difficult to monitor population trends with surveys like the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 190,000, with 7% living in the U.S. and 43% in Canada (with the remainder occurring in Eurasia). The State of North America’s Birds 2016 report rates the species an 11 out of 20 on the Continental Concern Score and it is not on the 2016 State of North America's Birds Watch List. In the United States, Great Gray Owls are at the southern limits of their range and are uncommon, but they are fairly common throughout their Holarctic range.

Credits

  • Bull, E.L., and J.R. Duncan. 1993. Great Gray Owl (Strix nebulosa), The Birds of North America (P.G. Rodewald, Ed.). Cornell Lab of Ornithology, Ithaca, New York.
  • Fetz, T.W., S. W. Janes, and H. Lauchstedt. 2003. Habitat characteristics of Great Gray Owl sites in the Siskiyou Mountains of southwestern Oregon. Journal of Raptor Research 37:315–322.
  • Lederer, R., and C. Burr. 2014. Latin for Bird Lovers: Over 3,000 bird names explored and explained. Timber Press, Portland, Oregon.
  • Mikkola, H. 2014. Owls of the World: A Photographic Guide. Firefly Books, Buffalo, New York.
  • North American Bird Conservation Initiative, U.S. Committee. 2014. State of the Birds 2014 Report. U.S. Department of Interior, Washington, DC.
  • North American Bird Conservation Initiative. 2016. The State of North America’s Birds 2016. Environment and Climate Change Canada: Ottawa, Ontario.
  • Partners in Flight. 2012. Species assessment database.
  • Sulkava, S., and K. Huhtala. 1997. The Great Gray Owl (Strix nebulosa) in the changing forest environment of northern Europe. Journal of Raptor Research 31:151-159.
  • USGS Patuxent Wildlife Research Center. 2016. Longevity records of North American Birds.
  • Van Riper, C., III, and J. Van Wagtendonk. 2006. Home range characteristics of Great Gray Owls in Yosemite National Park, California. Journal of Raptor Research 40:130–141.

Range Map Help

Great Gray Owl Range Map
View dynamic map of eBird sightings

Migration

Resident (nonmigratory). In some areas and in some years, Great Gray Owls irrupt, or move out of their normal range, traveling farther south or to lower elevations in search of food.

Backyard Tips

If you are lucky enough to live within the range of the Great Gray Owl, you can build a nest structure to attract a breeding pair. Make sure you put it up well before breeding season. You'll find plans for building a nest structure of the appropriate size on our All About Birdhouses site.

Find This Bird

The Great Gray Owl is an elusive bird that is not easy to find, despite its size. Your best chance of seeing one is during an irruptive year when it comes south in search of food. Join your local birding group email listserv and watch rare bird alters to know when one has been sighted near you. You can also use the eBird species maps tool to find areas where other birders reported them in the past to try your luck at finding one. In these areas slowly walk the perimeter of a meadow or other opening looking for dark figures in trees. Pay particular attention to dead trees and don’t forget to look at all levels in the trees as they can sometimes perch fairly low. To catch them hunting, make sure to get out in the right habitat before dawn or dusk. Because Great Gray Owls are highly sought-after by birders and photographers who want to see the birds, and are sensitive to disturbance, don’t use call playbacks to find them. Using mice to bait or lure in owls (of any species) should be avoided all together.

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