Great Gray Owls
Great Gray Owls have a talent for detecting and seizing prey under thick layers of snow and ice. One Great Gray Owl reportedly plunged through a crust of snow thick enough to support a 175-pound person!
Great Gray Owls inhabit boreal forests in Canada, northern Europe, and Siberia. Their North American range also includes limited areas of forest in the Cascades, Sierra Nevada, Rocky Mountains, and smaller ranges in the mountain states. Great Gray Owls prefer forest habitat adjacent to open meadows, bogs, or muskeg.
Most Great Gray Owl individuals, in most years, are nonmigratory. In certain years, however, prompted by rodent population crashes in their normal range, Great Gray Owls may become nomadic, irrupting as far southward as southern Canada and the northern United States. Invasions cause furious activity on rare-bird alert hotlines since, for most American birders, such events offer the best opportunity for viewing this spectacular bird. Great Gray Owls are often quite tame and easily approached in winter.
Great Gray Owls feed almost exclusively on small mammals, especially voles and pocket gophers. They usually hunt by perching on branches or treetops, watching and listening for prey below. They also hunt by ear alone, hovering above snow and plunging down to take prey under the surface. They fly with slow, deep, wingbeats. Great Gray Owls often hunt actively during daylight.
During courtship, male Great Gray Owls issue deep, booming hoots with a muffled quality. For nesting, Great Gray Owls use abandoned structures built by ravens or hawks. Females lay from two to five eggs (usually three). The whitish eggs are less round and more elliptical than those of most other owls; researchers speculate that this unusual shape may be an adaptation to prevent eggs from rolling out of platform nests. The female alone incubates the eggs and broods the hatchlings. The male forages for the female and young until fledging, which usually occurs between three and four weeks after hatching.
Great Gray Owls have large heads in the shape of a half dome, and relatively long, wedge-shaped tails. They have a large round facial disc, with several narrow concentric rings of white and gray around each eye. Their body plumage is mostly gray, with fine irregular stippling of gray, white, and some brown. Their eyes are yellow, and appear small within the owl's wide facial disc and massive head. Great Gray Owls have distinct white "bowties" under their chins; the bird's Russian common name, "Bearded Owl," refers to this marking.
Measuring up to about 32 inches from head to tail, Great Gray Owls are the largest owls in North America. Males and females have similar plumage but females are larger than males. Their massive appearance, however, is deceiving. Most of the Great Gray Owl's apparent bulk comes from its fluffy plumage and large head. Its body weight, at about 2.5 pounds, is less than that of the Great Horned Owl and the Snowy Owl.