The Great Gray Owl is the largest owl in North America and can be identified by its incredibly large size, round head lacking ear tufts, yellow eyes, and mottled gray and brown plumage. Locating a Great Gray Owl takes patience and knowing where to look, as these magnificent birds prefer dense, mature forests across Canada and the northern United States. Their camouflage plumage and silent flight make them elusive to spot. However, learning the Great Gray Owl’s appearance, behavior, habitat, range, vocalizations, and field marks can help birders reliably identify them.
Appearance
With a length of 24-33 inches, a wingspan around 5 feet, and weight of 2-5 pounds, the Great Gray Owl is much larger than most owls in North America. They have a very large, round head that lacks ear tufts and appears seamlessly connected to the body without a prominent facial disc. The eyes are also quite large and yellow.
The plumage is varying shades of mottled gray and brown which provides excellent camouflage in mature forests. The underparts are colored light gray and brown with dark streaks while the back and wings are a darker gray-brown. Fine white spotting occurs on the head and breast. Juveniles have more fuzziness to their plumage and a paler facial disk border.
In flight, the Great Gray Owl has broad, rounded wings and a short tail. The wingbeats are slow but powerful. When perched, the owl often sways back and forth or bobs its head. Sexes appear similar but females average larger in size. Compared to other owls, the Great Gray lacks ear tufts and has a larger, rounder facial disk.
Behavior
The Great Gray Owl is primarily nocturnal and roosts in dense conifer trees during the day. It has an incredibly keen sense of hearing and can locate small rodents under 2 feet of snow by sound alone. Its preferred hunting technique is to perch on a high branch and wait motionless until prey is heard. The owl then swoops down with its large talons outstretched to catch voles, pocket gophers, rabbits, mice, and other small mammals.
Great Grays are not territorial but have large home ranges. They may migrate south during winter or wander nomadically following rodent prey populations. Their flight is powerful but slow and often close to treetop level. The Great Gray is a solitary owl that is highly camouflaged and difficult to spot while roosting. However, it may grow habituated to humans over time.
Habitat
The Great Gray Owl occupies mature boreal or montane forests across Canada, Alaska, the Western Mountains, and northern parts of the Eastern United States. It prefers areas with a mix of coniferous and deciduous trees, dense understories, and meadow openings.
Great Grays require taller trees with cavities or broken tops for nesting. They are most often found in habitats with high populations of voles and other small rodents which they depend on for food. In the Pacific Northwest, they occupy mixed forests with Douglas fir, western hemlock, quaking aspen and other trees. Farther north they inhabit pure stands of spruce, fir, pine, and larch.
During winter, Great Grays may wander more widely or migrate south if prey populations decline. They can turn up almost anywhere with adequate forest cover as a result.
Range
The breeding range of the Great Gray Owl extends across Canada and Alaska as well as mountainous areas of the northwestern United States like Idaho, Montana, and Wyoming. Reaching the northern limits of trees, they can be found from sea level to elevations of 8,000 feet.
Small numbers breed in the Northeast from New York to Maine while scattered populations occur in the Great Lakes region and Pacific Northwest. During winter, some Great Gray Owls migrate south to southern Canada and the northern United States including parts of the Midwest and Northeast.
However, they are sparse and localized throughout their non-breeding range. Vagrant birds sometimes wander south to unusual locations outside their normal range.
Vocalizations
The most common vocalization of the Great Gray Owl is a series of deep, rhythmic hoots described as “Whoo, hoo-hoo, hooooo-hoo-hoo, hoo.” The male’s call is lower pitched than the female’s. This territorial hooting is often done as a duet by paired owls and carries well through the boreal forest.
Other sounds include a croaking “krek-krek” given around the nest and soft whistles used during courtship. Young Great Grays beg with a hissing noise when parents arrive with food. When threatened, this owl may clap its bill or produce a harsh rasping call. Wings make a soft whooshing noise in flight.
Field Marks
When conducting field identification, the Great Gray Owl’s incredibly large size, round head, and yellow eyes are distinctive. The lack of ear tufts and mottled gray and brown plumage separates them from other owls. Close views would show the streaked underparts and fine white spotting.
The Great Gray perches in a vertical position for long periods, swaying back and forth. In forest openings, listen for its low hooting territorial call. The owl may also be seen flying over roads or clearings at dusk or dawn with its large, rounded wings.
Here are key field marks for identifying a Great Gray Owl:
- Very large size – Among the biggest North American owl species
- Round, flat face – Lacks prominent ear tufts or facial disc
- Yellow eyes – Contrast against darker facial disk
- Mottled gray & brown plumage – Provides camouflage in mature forests
- Heavy streaking on underparts
- Often sways or bobs head while perched
Similar Species
The Great Gray Owl is unlikely to be confused with other owls except potentially the Great Horned Owl. The Great Horned is smaller with prominent ear tufts, barred rather than streaked underparts, and yellow eyes.
Barred and Spotted Owls are also smaller with ear tufts. Snowy Owls lack streaking and are all white. The Long-eared Owl has orange eyes and streaked plumage but is much smaller in size. Northern Hawk Owls are also smaller and have a dark facial disk border.
If the extremely large size is clearly noted, the identity of a Great Gray Owl is straightforward. At a distance, always double check relative size to confirm the species.
When and Where to See
Finding a Great Gray Owl takes effort due to its camouflage plumage, silent nature, and residence in dense boreal forests. The best locations are within the breeding range in Canada and Alaska as well as northern Idaho, Montana, and Wyoming where populations live year-round. Focus search efforts in areas with recent reports.
Early in the breeding season between February and April is a good time to listen for territorial hooting by Great Grays. Later in spring, they can be found in forest openings near nest sites where they hunt. Autumn and winter offer the possibility to spot roaming birds that wander south of their normal range.
Great Gray Owls are most active around dusk, dawn, and at night when they hunt small rodents by sound. However, they can be observed in daytime perched on tree branches near meadow openings. Patiently scanning snags in mature mixed or coniferous forests offers the best chance to spot this master of camouflage.
Fun Facts
- The Great Gray Owl nests in existing nests or tree cavities rather than building its own nest.
- Prey are located by sound under snow, leaves, grass, and other cover thanks to exceptional hearing.
- This owl has a large facial disk for collecting sound waves but lacks actual ear openings.
- Great Grays are one of the only avian predators of porcupines due to their dense plumage.
- They depend on cyclic populations of voles and other small rodents, breeding when prey is abundant.
- The owl cannot digest hair and feathers, regurgitating pellets of indigestible prey remains.
- Great Gray Owls live year-round on their breeding territories as long as food supplies permit.
- Their huge size helps them survive cold winters farther north than most other owls.
Conclusion
The Great Gray Owl may reign as the most impressive owl in North America for its colossal size yet subtle beauty. Patient birders can observe this majestic hunter by learning its appearance, habits, and preferred boreal forest home. Just listening for its resonant hooting carries the imagination to far-off wildernesses where the Great Gray Owl patrols the endless conifer woods in silent flight.
