Great Grey Owl
Strix nebulosa
Visual Identification
Appearance
The Great Grey Owl is a massive, imposing bird with a large, rounded head lacking ear tufts. Its plumage is predominantly grey with brown streaks and bars, featuring a distinctive facial disc with concentric grey circles and striking yellow eyes.
Females are typically larger than males, but plumage is similar. Juveniles resemble adults but may have a slightly browner overall appearance with less defined facial markings. They develop a more adult-like plumage after 5 months.
Size
Length
61cm to 84cm
Wingspan
137cm to 152cm
Weight
790g to 1.454kg
Colours
Males and females have similar plumage
Primary Colour
Grey Brown
Secondary Colour
White
Beak Colour
Yellow
Leg Colour
Grey
Habitat and Distribution
Habitats
Woodland
Garden
Wetland
Coastal
Urban
Farmland
Grassland
Desert
Tundra
Rainforest
Mountain
Savanna
Distribution
Great Grey Owls inhabit dense coniferous and mixed forests across the northern hemisphere, including boreal regions of North America, Europe, and Asia. They prefer areas with nearby open spaces for hunting.
In North America, they are found in Alaska, Canada, and parts of the northern United States, with some populations in mountainous areas further south. Seasonal movements are often influenced by prey availability rather than temperature.
Montana’s Glacier National Park and the Bitterroot Valley are known for their Great Grey Owl populations. Similarly, sightings are also regularly reported in Idaho’s Bitterroot Mountains and the Panhandle region. To the west, they are also occasionally spotted at Okanogan-Wenatchee National Forest in Washington.
In Canada, the forests and meadows of Riding Mountain National Park in Manitoba offer a decent chance of spotting a Great Grey Owl. Ontario’s Algonquin Provincial Park is known for its diverse resident wildlife, including Great Grey Owls.
Elevation Range
Up to 3,200 meters
Climate zones
Subarctic, Temperate
Distribution Map
This map gives you a rough idea of where you might spot a Great Grey Owl. The coloured areas show countries where these birds have been seen.
A few things to keep in mind:
- Birds might not be everywhere in the coloured areas, for example, they may be present around the coast of that country
- Where birds live can change with seasons and available food
- This map is quite simple - it doesn't show exact locations
We're working on making our maps even better! Soon, we hope to show you:
- More detailed maps for bigger countries, including state and region
- How birds move around during different seasons
Behaviour and Ecology
Bird Attributes
This feature is in beta. We'd love your feedback to improve it!
Share your thoughtsBird Attributes Explained
Our bird attributes system rates various aspects of a bird's capabilities on a scale of 0-100, based on data from field observations, scientific studies, and expert knowledge.
Attribute Categories:
- Agility: Manoeuvrability, speed, and grace in flight or movement.
- Strength: Physical power, often correlating with size and hunting abilities.
- Adaptability: Ability to thrive in various environments or changing conditions.
- Aggressiveness: Territorial behaviour and assertiveness, particularly during breeding seasons.
- Endurance: Stamina, often seen in migration patterns or foraging behaviours.
Understanding the Ratings:
- 0-20: Very Low
- 21-40: Low
- 41-60: Average
- 61-80: High
- 81-100: Very High
Remember, these attributes are relative to other bird species and don't necessarily indicate superiority.
Hover over the icon next to each attribute for more information.
Tap the icon next to each attribute for more information.
Agility
Reflects the bird's manoeuvrability, speed, and grace in flight or movement.
The Great Grey Owl demonstrates remarkable agility in flight and hunting. Its ability to precisely locate and capture prey beneath snow, coupled with silent flight due to specialised feathers, indicates exceptional manoeuvrability and control.
Strength
Indicates the bird's physical power, often correlating with size and hunting abilities.
Whilst not the strongest owl species, the Great Grey Owl possesses considerable strength for its size. Its ability to plunge through snow to capture prey and carry off small mammals suggests a robust physical capability.
Adaptability
Represents the bird's ability to thrive in various environments or changing conditions.
This species shows impressive adaptability, thriving in various forest types across the northern hemisphere. Its capacity to hunt in both nocturnal and diurnal conditions, particularly in regions with extended daylight, demonstrates notable flexibility.
Aggressiveness
Measures the bird's territorial behaviour and assertiveness, particularly during breeding seasons.
Great Grey Owls are generally not highly aggressive, preferring solitude outside breeding season. However, they display assertiveness in hunting and likely in nest defence, though specific data on territorial behaviour is limited.
Endurance
Reflects the bird's stamina, often seen in migration patterns or foraging behaviours.
The owl's ability to survive in harsh subarctic climates and hunt effectively in deep snow indicates substantial endurance. Its partial migratory behaviour and capacity for sustained hunting activity also suggest good stamina, though precise data on long-term physical exertion is not available.
Diet
Great Grey Owls primarily hunt small mammals, with voles being a staple food source. They use their exceptional hearing to locate prey beneath snow or vegetation, plunging feet-first to capture it.
Pocket gophers, shrews, red and flying squirrels, mice, lemmings, weasels, and chipmunks are the most commonly caught prey. Birds are also taken but do not represent as important a share as mammals, with ducks, grouse, and songbirds.
Behaviour
Great Grey Owls are primarily nocturnal but may also hunt during daylight hours, especially in northern latitudes with extended summer daylight. They often perch motionless on tree branches, scanning for prey with their exceptional hearing. These owls are generally solitary outside of the breeding season.
Vocalisation
The Great Grey Owl's call is a series of deep, resonant hoots, typically described as "whoo, whoo, whoo, whoo, whoo." This call can carry for long distances through the forest. They also produce a variety of other vocalizations, including a soft, two-note "oo-ah" during courtship.
Nesting & Breeding
Great Grey Owls typically form monogamous pairs and begin breeding in late winter or early spring. They do not build their own nests; instead, they use abandoned nests of other large birds or natural platforms in trees.
Females lay 2-5 white eggs, which are incubated for about 30 days. The eggs are usually laid at 2-day intervals, resulting in asynchronous hatching.
Nestlings are covered in white down at hatching and fledge after about 30-40 days, though they remain dependent on their parents for several months as they learn to hunt.
Conservation and Status
Global Conservation Status
While listed as Least Concern globally, Great Grey Owls face localized threats from habitat loss due to logging and climate change. Conservation efforts focus on preserving large tracts of mature forest and maintaining suitable hunting grounds in open areas adjacent to forests.
Birdwatching Tips
- Look for them in dense coniferous or mixed forests near open areas
- Listen for their deep, resonant hooting calls at night
- Scan for their distinctive large, round head shape silhouetted against the sky
- In winter, watch for them hunting in meadows or clearings during daylight hours
- In North America, visit boreal forests in Canada or northern US states for the best chances of spotting them
Additional Information
Quick Facts
Other names:
Phantom of the North, Great Gray Owl, Lapland Owl
Family:
StrigidaeAverage Lifespan
10 to 15 years
Predators
Adult Great Grey Owls have few natural predators, but eggs and young may fall prey to ravens, martens, and other large owls. Humans pose the greatest threat through habitat destruction.
Did You Know?
- Great Grey Owls have asymmetrical ear openings, allowing for precise sound localization.
- They can detect prey moving beneath up to 60 cm of snow.
- Despite their large size, Great Grey Owls weigh less than many smaller owl species due to their fluffy plumage.
References
- 1
website: BirdLife International. 2021. Strix nebulosa. The IUCN Red List of Threatened Species 2021: e.T22689118A199144259.
View source - 2 3
report, 2021: Partners in Flight
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