Great gray owlGreat Gray Owl

Strix nebulosa
By Sam Curtis. Photo by Donald M. Jones

While looking for elk sign in the knee-deep snow at the edge of a forest clearing in the Gallatin Range, I noticed a lodgepole pine, its top apparently snapped off by strong winds. Then the top of the broken tree rotated, becoming a feathered head with a facial disk studded with two piercing yellow eyes. The gaze of the great gray owl stopped me midstride.

For the next 15 minutes, I forgot all about elk and stood dead still watching the reclusive owl deliberately scanning the surrounding terrain. Finally it dove from its perch and plunged into the snow for a rodent burrowing below the surface. The sight remains one of my most memorable wildlife encounters.

The great gray is North America’s largest owl. The female has a wingspan of 4.5 feet and stands 28 inches tall. The bird weighs only about 2 pounds, so most of its mass is just feathers. Males are somewhat smaller but otherwise similar in appearance: mostly gray colored and with a relatively long tail and no ear tufts on the head. The great gray’s most striking feature is a huge facial disk covering the front of the head containing concentric gray circles surrounding bright yellow eyes. At the bottom edge of the disk is a white “moustache” strip broken by a black “bow tie” below the yellow beak.

The great gray makes territorial announcements and calls its mate with an appropriately owlish whoo-whoo-whoo, repeated softly in a low pitch every 15 to 30 seconds, usually at night.

The great gray owl is also known as the spectral owl, perhaps for the way it flies silently through the forest at night or its haunting alarm cry. The scientific name nebulosa, from the Latin nebulosus, meaning “misty” or “foggy,” also suggests ghostlike characteristics.

Range and habitat
Montana is one of the few states in the lower 48 where great gray owls live. Other than Canada and Alaska, where it is common, the species is found only in Minnesota, the central Sierra Nevadas, and the northern Rockies as far south as Yellowstone National Park. The bird is also found throughout northern Asia and Europe, where it is often known as the Lapland owl.

In Montana, the great gray is found in mixed conifer forests interspersed with swamps, meadows, and small clearings where bordering trees and snags provide hunting perches.

The great gray’s exceptional eyesight and hearing allow it to detect mice, voles, and other small animals that comprise its diet. Though this owl sometimes hunts on the wing, flying close to the ground, it usually plays a waiting game, surveying the open area below a hunting perch for sounds and movement.

Even rodents burrowing a foot beneath the snow are vulnerable to the owl’s sharp senses. A great gray will plunge talon first into deep snow for a meal, leaving spread wing prints and a few drops of blood as evidence of the attack.

These owls are a resident species in Montana, moving around during the year in search of food. Studies in Wyoming show their average home range to be roughly 1.6 square miles. The raptors tend to move from higher to lower elevations when prey is scarce and snow is deep. Where prey is abundant, great gray owls may congregate in high densities of up to five pairs per square mile. Although they tolerate other great grays in foraging areas, the owls are aggressively territorial around nesting sites.

Nesting begins in March and April when the male offers the female food from his beak, which she accepts with her eyes closed. Then the male shows the female several nesting possibilities in abandoned hawk or raven nests or hollowed-out clumps of dwarf mistletoe. Once the female chooses a nest, the pair often line it with moss or deer or elk hair.

The female lays an average of three eggs, which she incubates for 28 days. The male provides food, which the female shreds to feed the young. Within three or four weeks, the fledglings are leaving the nest and climbing around in the nesting tree. They can fly by eight weeks but stay near the nest and parental care for two or three months after that.

Great gray owl populations appear to be healthy within their range in Montana and throughout North America.Bear bullet