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NYCTEA SCANDIACA (BUBO SCANDIACUS)

APPEARANCE

Large to very large white owl; female distinguished from almost pure white male by more extensive dark barring on upper parts, crown, and flanks; yellow eyes; black bill almost covered by white facial disk; heavily feathered feet; long wings, with dark banding on tips of flight feathers.

SIZE

length 20 – 28 in. (52 – 71 cm)

weight 3.5 – 6.6 lb (1.6 – 3 kg)

wingspan 49 – 59 in. (125 – 150 cm)

DISTRIBUTION

Circumpolar range across Old and New World Arctic: in North America, from the Western Aleutians east to northern Quebec and Labrador; in Eurasia, from Lapland east across Arctic Russia; winters further south: in North America, southern Canada, and the northern United States; in Eurasia, Kazakhstan, Mongolia, and northern China.

STATUS

Least Concern

THE INUIT CALL THIS BIRD OOKPIK, and at one time they used its feathers to fletch their hunting arrows. Fans of J. K. Rowling will know it as Hedwig, the messenger owl that carries post to Harry Potter. Whatever you call it, the Snowy Owl is not only the world’s most unmistakable owl, but also one of its most impressive birds. The scientific name “scandiaca” reflects the fact that it was first described to science in Scandinavia. However, this circumpolar Arctic owl has its largest population in North America and is, today, the official bird of Quebec.

“Big and white” is the only description needed in order to identify this owl. It is between the Eurasian Eagle Owl and the Great Horned Owl in size, and its snow-white plumage is unlike that of any other species. The black-rimmed yellow eyes seem particularly dazzling against the white face, and the feet are as thickly feathered as you would expect for an animal that lives most of its life in the snowy Arctic. In addition to its unique coloration, the Snowy Owl is one of the most sexually dimorphic of owls. Mature males are almost totally white, with the exception of a few dusky spots on the crown and dusky barring on the tips of the flight feathers, but the larger females are more heavily marked, with dark brown spotting and barring on the crown and upper parts, the flight feathers, tail feathers, and flanks. Despite their markings, however, females still appear predominantly white.

Although long placed in the Bubo genus, along with eagle owls and the Great Horned Owl, many taxonomists today assign the Snowy Owl to its own genus, Nyctea. Whatever the taxonomy, its white plumage and thick feathering are both adaptations to life in the Arctic—just like the similar adaptations of the Arctic fox (Vulpes lagopus), snowshoe hare (Lepus americanus), and rock ptarmigan (Lagopus muta). It ranges right across the Arctic regions of both the Old and New Worlds, but despite this wide distribution, the Snowy Owl is a monotypic species, with only one race recognized.

This bird is nomadic, moving south when conditions become too harsh or the rodent population crashes. In North America, this means heading into southern Canada and the northern United States, with some birds traveling as far as Texas and Georgia. In Eurasia, the wintering quarters extend to Kazakhstan, Mongolia, and northern China. Young males make the longest journeys and older females the shortest. Long-distance travelers may make a series of stop-offs as they head south, defending a temporary territory in each. The Snowy Owl’s nomadic existence means that it moves between different habitats. Its tundra breeding grounds comprise largely treeless terrain, coated with mosses and lichens and punctuated with boulders and patches of snow that remain throughout the summer. Moving south in winter, it exchanges this barren terrain for lake shores, marshes, coastlines, and fields.

A diurnal predator, the Snowy Owl is active between dawn and dusk. On its breeding grounds, it is often seen perched on small tundra mounds or flying low from one perch to the next. Its flight is powerful, with deliberate rowing beats of its long wings and long glides in between. The main hunting strategy is sit and wait: the owl scans the open tundra and then, when a target is spotted, attacks in a long, shallow glide. Voles and lemmings—the small rodents that breed prolifically during the Arctic summer—are its principal prey. It may also take larger mammals, such as snowshoe hares, and targets birds, including ducks and geese, taking them in flight or from the water’s surface. In addition, it may use those sharp talons to pluck fish from the water.

A male Snowy Owl arrives at the tundra nest with his prey.

The Snowy Owl is seldom monogamous. Its changing terrain and long journeys mean that it often finds itself setting up a new territory with a new partner, although pairs have been known to stick together for up to five years. During courtship, the male calls with a booming “hoo hoo”— up to six repeated notes—to which the female responds with harsher, higher calls. He backs up his vocal performance with an impressive display, flying in undulating circles with exaggerated moth-like wingbeats, then descending to bow and strut on the ground, feathers fluffed out, tail cocked, and wings drooping or held up like an angel’s. The nest is made on the ground; there is little choice in the Arctic tundra. A site is chosen that is free from snow and in a productive hunting area, with a good view of the surrounding landscape. The female uses her feet to scrape a shallow depression on top of an elevated mound, which she then lines with a little vegetation and a few feathers.

The clutch size of the Snowy Owl varies from an average of five to eight eggs to an astonishing fourteen or more in peak lemming years. The female lays her eggs at two-day intervals, then incubates them while the male brings food and stands guard. During this period, the parents toil hard. The growing chicks eat two lemmings per day, and a single family may consume up to 1,500 lemmings before the young disperse. Meanwhile, the male defends the nest vigorously. The open terrain means that approaching enemies are easily visible, and the owls have been known to attack Arctic foxes at least 0.6 miles (1 km) away from the nest. If an intruder breaches the male’s defenses, the female will attempt to lure it away with a distraction display. The owls do not hunt immediately around their nest. This means that birds such as the snow goose (Chen caerulescens), which might otherwise be prey, often nest near the owl in order to gain its protection from foxes and other nest raiders.

Numbers of Snowy Owls fluctuate wildly, according to prey availability: the birds become locally abundant in a boom year, then almost disappear the next. Their greatest threat may be climate change, which in bringing about the slow “greening” of the Arctic tundra in some areas may deprive the Snowy Owl of the very habitat for which it is so beautifully evolved.

Snowy Owls may make use of farmland during their winter journey south.

A male Snowy Owl passes food to the female while the youngsters look on.

The heavy dark barring on this Snowy Owl, plus its greater size, identifies it as a female.

A female Snowy Owl taking flight reveals feet that are more thickly feathered than in any other owl species.

The Snowy Owl approaches prey in a low glide, often hidden by the contours of the ground until the last, fatal moment.

The facial markings of the Boreal Owl give an impression of permanent surprise.