Measurements
Both Sexes
- Length
- 20.5–28 in
52–71 cm - Wingspan
- 49.6–57.1 in
126–145 cm - Weight
- 56.4–104.1 oz
1600–2950 g
Relative Size
- About the size of a Great Horned Owl.
Other Names
- Harfang des neiges (French)
Cool Facts
- The Snowy Owl can be found represented in cave paintings in Europe.
- In some years, some North American Snowy Owls remain on their breeding grounds year-round, while others migrate in winter to southern Canada and the northern half of the contiguous United States. In the northern plains, New York, and New England, Snowy Owls occur regularly in winter. Elsewhere, such as in the Pacific Northwest, the Midwest, and eastern Canada, Snowy Owls are irruptive, appearing only in some winters but not in others.
- Male Snowy Owls are barred with dark brown when they’re young and get whiter as they get older. Females keep some dark markings throughout their lives. Although the darkest males and the palest females are nearly alike in color, the whitest birds—including the ones that played Harry Potter’s Hedwig—are always males and the most heavily barred ones are always females.
- Snowy owls are territorial on their breeding areas, and sometimes their wintering areas as well. Some Snowy Owls defend their winter territories fiercely, even engaging in combat with other Snowy Owls (a behavior not recorded on their breeding territory). Some banded Snowy Owls return to the same wintering site year after year.
- Unlike most owls, Snowy Owls are diurnal, extremely so. They’ll hunt at all hours during the continuous daylight of an Arctic summer. And they may eat more than 1,600 lemmings in a single year.
- Snowy Owl young may disperse remarkably far from their birthplace. From a single Snowy Owl nest on Victoria Island in the Canadian Arctic, one young bird went to Hudson Bay, one to southeastern Ontario, and one to the far eastern Russian coast.
- Thick feathers for insulation from Arctic cold make Snowy Owls North America’s heaviest owl, typically weighing about 4 pounds—one pound heavier than a Great Horned Owl and twice the weight of a Great Gray Owl (North America’s tallest owl).
- John James Audubon once saw a Snowy Owl lying at the edge of an ice hole, where it waited for fish and caught them using its feet.
- The oldest-known Snowy Owl was banded in Massachusetts in 1988 and found again in Massachusetts in 2004. It was at least 16 years, 8 months old.
Habitat
Grassland
Whether the tundra or the Great Plains, an airport field or beach dunes, Snowy Owls like treeless places and wide-open spaces. Because they often sit right on the ground to hunt, they prefer rolling terrain where they can find a vantage to survey the surrounding area. On their wintering grounds they’ll also perch atop a fencepost, hay bale, building, telephone pole, grain elevator—anywhere with a good view.
Food
Mammals
Snowy Owls mainly eat small mammals, particularly lemmings, which at times on the tundra may be all these birds eat. Sometimes they’ll switch to ptarmigan and waterfowl. Snowy Owls are also one of the most agile owls, able to catch small birds on the fly. On both their breeding and wintering grounds, their diet can range widely to include rodents, rabbits, hares, squirrels, weasels, wading birds, seabirds, ducks, grebes, and geese.
Nesting
Nesting Facts
- Clutch Size
- 3–11 eggs
- Number of Broods
- 1 broods
- Egg Length
- 2.2 in
5.7 cm - Egg Width
- 1.8 in
4.5 cm - Incubation Period
- 32 days
- Nestling Period
- 18–25 days
- Egg Description
- White.
- Condition at Hatching
- Wet and blind (eyes usually open by day 5); within hours a Snowy Owl hatchling is a little white fluff ball of downy feathers.
Nest Description
The Snowy Owl female builds the nest, scraping out a shallow hollow on the bare ground and shaping it by pressing her body into the depression. The process takes a few days, and the owls may reuse the nest site for many years.
Nest Placement
Ground
It is thought that the male selects the territory, and the female chooses the nest site within the territory. Snowy owls nest right on the tundra. They prefer slight, windswept rises that will be dry and blown free of snow.
Behavior
Aerial Dive
Snowy Owls do a lot of sitting. They sit still in the same spot for hours, occasionally swiveling their head or leaning forward and blinking their big, yellow eyes to get a closer look at something. When they hunt, they use extraordinary vision and hearing to draw a bead on their prey—maybe a vole scurrying beneath the snow—and then fly, or even run, over to pounce on it. If successful, they’ll down the rodent headfirst in a single gulp. On their breeding grounds, male Snowy Owls execute a fascinating mating display. First the male rises into the air with exaggerated wingbeats in an undulating flight, holding a lemming in his bill or talons. Then he descends to the ground with wings flapping or held in a "V." He drops the prey on the ground, stands erect, then lowers his head and fans his tail as the female approaches. To defend his territory from another Snowy Owl, a male lowers his head and sticks it forward, extending his wings and raising the feathers on his neck and back to seem bigger. To defend against other species, Snowy Owls have been known to dive-bomb and strike at humans. Once it was reported that a Snowy Owl attacked a pair of arctic wolves.
Conservation
Least Concern
Snowy Owls nest in remote areas, have huge territories, and in winter their migrations are widespread and unpredictable, so it’s very difficult to estimate their population size. Like all raptors, Snowy Owls are protected from trapping and shooting, and this may protect them during winters in populated areas. Their remote breeding grounds are largely free from direct human disturbance, although it’s not clear how climate change will affect them. The Snowy Owl population probably rises and falls with the population cycles of its prey; for example, on Banks Island in Canada, the Snowy Owl breeding population has ranged from 2,000 to 20,000.
Credits
- Parmelee, D. 1992. Snowy Owl (Bubo scandiacus). In The Birds of North America, No. 10 (A. Poole, P. Stettenheim, and F. Gill, Eds.). The Birds of North America Online, Ithaca, New York.
- American Ornithologists' Union. 2003. Forty-fourth supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 120: 923-931.
- USGS Patuxent Wildlife Research Center. 2011. Longevity Records of North American Birds.
Migration
Irruptive medium- to long-distance migrant. Snowy Owl migrations are extremely variable. Some North American Snowy Owls winter in southeastern Canada, the upper Great Lakes states, and New England just about every year. Winter numbers of Snowy Owls in the U.S. peak periodically, which may be attributed to lemming cycles farther north. During irruptive years, Snowy Owls can flush south throughout the lower 48 states, as far as south as Texas and Florida in extreme years.
Find This Bird
Unless you visit the high arctic, you’ll mainly be looking for Snowy Owls during winter in wide-open areas such as fields and shorelines. Scan snowy flat areas and be on the lookout for any irregularities in the snow. A lump or dirty patch could be a Snowy Owl facing away from you. Snowy Owls like to perch in conspicuous areas, so be sure to check high points like hay bales, fenceposts, telephone poles, buildings, or grain elevators. Also look for agitated birds—other raptors or gulls may swoop at a Snowy Owl sitting on a beach.