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Snowy Owl

Bubo scandiacus

Description

This owl is aptly named, as both males and females are predominantly white in color, which allows them to all but disappear into the snowy tundra upon they live. Both sexes develop brownish markings in the summer, when the snow gives way to grasslands and fields, with females being much more prominently marked. Juveniles are dark grayish-brown in color.

male
male snowy owl

female
female snowy owl

One of the largest members of the owl family, the snowy is 20-27 inches long, has a wingspan of 54-65 inches, and weighs 2.5-4.5 pounds. Females are larger and heavier than males.

Distribution and Habitat

The snowy owl has a circumpolar distribution, being found in the Arctic regions of North America, Europe, and Asia. They favor treeless places and wide-open spaces, with a special preference for rolling terrain where they can find a vantage point from which they can survey the surrounding area. Although snowy owls often move south in the winter, they do so in order to follow prey, not to find a warmer climate.

Diet

Unlike other owls, snowy owls hunt during the day, from dawn to dusk, and will hunt at all hours during the continuous daylight of an Arctic summer.

Rodents, especially lemmings, make up most of the diet, but snowy owls will eat almost any kind of prey they can catch, including other birds and fish. They have also been known to raid traplines for trapped animals and bait, and will take carrion if live prey is unavailable. Prey are captured on the ground, in the air, or snatched off the surface of water bodies. Small prey are swallowed whole, while larger prey are carried away and torn into large chunks. Small young are fed boneless and furless pieces.

Reproduction

Males begin courting females in mid-winter. In addition to aerial and ground "displays," males often kill and display prey in caches to impress females. Breeding and nesting generally occurs in May, when prey numbers are typically at their highest.

The snowy owl nests almost exclusively on the ground, where the female makes a shallow scrape with her talons on top of an elevated rise, mound, or boulder and lines it with scraps of vegetation and feathers. Nest sites must be near good hunting areas, be snow-free, and command a view of surroundings. There is little breeding site-faithfulness between years or mates in some areas, but in other areas, a pair of owls may nest in the same spot for several years.

Clutch sizes normally range from 5 to 8 white eggs, but may be as many as 14 eggs during high lemming years. They are laid at approximately two-day intervals. The female incubates while the male brings her food and guards the nest. Eggs hatch in 32-34 days, at two-day intervals. Young begin to leave the nest after about 25 days, and fledge at 50 to 60 days. Both parents feed and tend the young. They are both fiercely protective of both eggs and young, and may attack intruders up to a half-mile away. Parental care and protection ends once the young can hunt on their own.

Snowy owls can live at least 9.5 years in the wild, and 35 years in captivity.

Other Habits and Behaviors

Snowy owls have a direct, strong, and steady flight, with deliberate, powerful downstrokes and quick upstrokes. They typically make short flights, close to the ground, from perch to perch or perch to ground.

Normally silent, snowy owls can become quite vocal during the breeding and nesting season. The typical call of the male is a loud, harsh, grating bark, while the female has a similar higher pitched call. During the breeding season males have a loud, booming "hoo, hoo" given as a territorial advertisement or mating call. Females rarely hoot. Its alarm call is a guttural "krufff-guh-guh-guk." When excited it may emit a loud "hooo-uh, hooo-uh, hooo-uh, wuh-wuh-wuh." Other sounds are dog-like barks, rattling cackles, shrieks, hissing, and bill-snapping.
Nestlings "cheep" up to 2 weeks of age, then hiss and squeal.

Scientific Classification

phylum Chordata
subphylum Vertebrata
class Aves
order Strigiformes
family Strigidae
genus & species Bubo scandiacus

SOURCE
The Owl Pages www.owlpages.com/owls.php?genus=Bubo&species=scandiacus

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The Robinson Library >> Science >> Zoology >> Birds >> Order Strigiformes

This page was last updated on June 11, 2017.