Minnesota Profile: Great Gray Owl (Strix nebulosa)

Appearance The great gray owl has a big, domelike head and a flat facial disc, its most conspicuous feature. North America's tallest owl species, the great gray stands about 27 inches and has a wingspan exceeding 4 feet. But this imposing owl is mostly feathers. It typically weighs just 2.4 pounds. Its thick, downy plumage is a vital adaptation for living in northern forests, where temperatures can drop to minus 40 F.

Range and habitat Great gray owls reside in boreal forests in Europe, Asia, and North America. Because populations of voles (their favorite food) rise and fall cyclically in northern regions, the owls move south when vole populations crash. As rodent numbers recover, owls move northward.

Status State and federal laws protect this uncommon owl. The species is not threatened or endangered worldwide.

Hunting behavior A great gray owl can find and catch a vole hidden beneath 2 feet of snow. A diurnal bird, the great gray actively feeds in the daytime. It hunts by perching on a tree branch or post and listening for rodents scurrying under snow or ground litter. The owl's facial disc works like a pair of parabolic reflectors to focus sound back to its ear holes, positioned asymmetrically alongside its head. When the owl pinpoints its prey, it drops from its perch and glides silently toward it. Needle-sharp talons extend from two forward toes and two backward toes on each foot. When its feet touch the prey, its toes snap together like an avian mousetrap.

Nesting Great gray owls begin nesting in March and April. Three to five eggs usually hatch in 29 days. The male parent brings dead voles to the female to feed the young. After two to three weeks, the young leave the nest. Though the female remains nearby, the male takes over feeding the fledglings.

Common ravens sometimes prey on owl eggs and young. Great horned owls may prey on young and adult great grays. In places with roads, cars are the greatest cause of great gray owl mortality.

Observing Look for great gray owls along country roads in northeastern and far northwestern Minnesota at any time of day from December through March. Be extremely careful where you stop on roads, so you do not create a safety hazard for other drivers. Watch for information on owl viewing in DNR news releases, which can be read online at www.dnr.state.mn.us/news/releases.

Carrol Henderson, DNR Nongame Wildlife Program supervisor

Web site for more information
www.dnr.state.mn.us/snapshots/birds/greatgrayowl.html