The Snowy Owl (Bubo scandiacus) is a large owl of the typical owl
family Strigidae. Until recently, it was regarded as the sole member of a
distinct genus, but data now shows
that it is very closely related to the horned owls.
This yellow-eyed, black-beaked white bird is easily recognizable. It is
52–71 centimetres (20–28 in) long, with a 125–150 centimetres (49–59 in) wingspan.
Also, these birds can weigh anywhere from 1.6 to 3 kilograms (3.5 to 6.6 lb).
It is one of the largest species of owl and, in North America, is on average
the heaviest owl species. The adult male is virtually pure white, but females
and young birds have some dark scalloping; the young are heavily barred, and
dark spotting may even predominate. Its thick plumage, heavily feathered
taloned feet, and colouration render the Snowy Owl well-adapted for life north
of the Arctic Circle.
Snowy Owl calls are varied, but the alarm call is a barking, almost
quacking krek-krek; the female also has a softer mewling pyee-pyee or
prek-prek. The song is a deep repeated gahw. They may also clap their beak in
response to threats or annoyances. While called clapping, it is believed this
sound may actually be a clicking of the tongue, not the beak.
Young owl on the tundra at Barrow Alaska. Snowy Owls lose their black
feathers with age, though particular females retain some.
The Snowy Owl is typically found in the northern circumpolar region,
where it makes its summer home north of latitude 60 degrees north. However, it
is a particularly nomadic bird, and because population fluctuations in its prey
species can force it to relocate, it has been known to breed at more southerly
latitudes.
This species of owl nests on the ground, building a scrape on top of a
mound or boulder. A site with
good visibility such as the top of mound with ready access to hunting
areas, and a lack of snow is chosen. Gravel bars and abandoned eagle nests may
be used. The female scrapes a small hollow before laying the eggs. Breeding
occurs in May to June, and depending on the amount of prey available, clutch
sizes range from 5 to 14 eggs, which are laid singly, approximately every other
day over the course of several days. Hatching takes place approximately five
weeks after laying, and the pure white young are cared for by both parents.
Although the young hatch asynchronously, with the largest in the brood
sometimes 10 to 15 times as heavy as the smallest, there is little sibling
conflict and no evidence of siblicide. Both the male and the female defend the
nest and their young from predators, sometimes by distraction displays. Males
may mate with two females which may nest about a kilometre apart.[3] Some
individuals stay on the breeding grounds while others migrate.
Snowy Owls nest in the Arctic tundra of the northermost stretches of
Alaska, Canada, and Eurasia. They winter south through Canada and northern
Eurasia, with irruptions occurring further south in some years. Snowy Owls are
attracted to open areas like coastal dunes and prairies that appear somewhat
similar to tundra. They have been reported as far south as the American states
of Texas, Georgia, the American Gulf states, southernmost Russia, and northern
China.
In January 2009, a Snowy Owl appeared in Spring Hill, Tennessee, the
first reported sighting in the state since 1987. More notable is the huge mass
southern migration in the winter of 2011/2012, when thousands of Snowy Owls
were spotted in various locations across the United States.
This powerful bird relies primarily on lemmings and other small rodents
for food during the breeding season, but at times of low prey density, or
during the ptarmigan nesting period, they may switch to favoring juvenile
ptarmigan. They are opportunistic hunters and prey species may vary
considerably, especially in winter. They feed on a wide variety of small
mammals such as meadow voles and deer mice, but will take advantage of larger
prey, frequently following traplines to find food. Some of the larger mammal
prey includes hares, muskrats, marmots, squirrels, rabbits, raccoons, prairie
dogs, rats, moles, and smaller birds entrapped furbearers. Birds preyed upon
include ptarmigan, other ducks, geese, shorebirds, pheasants, grouse, coots,
grebes, gulls, songbirds, and even other raptors, including other owl species.
Most of the owls' hunting is done in the "sit and wait" style; prey
may be captured on the ground, in the air or fish may be snatched off the
surface of bodies of water using their sharp talons. Each bird must capture
roughly 7 to 12 mice per day to meet its food requirement and can eat more than
1,600 lemmings per year.
Snowy Owls, like many other birds, swallow their small prey whole.
Strong stomach juices digest the flesh, while the indigestible bones, teeth,
fur, and feathers are compacted into oval pellets that the bird regurgitates 18
to 24 hours after feeding. Regurgitation often takes place at regular perches,
where dozens of pellets may be found. Biologists frequently examine these
pellets to determine the quantity and types of prey the birds have eaten. When
large prey are eaten in small pieces, pellets will not be produced.
Though Snowy Owls have few predators, the adults are very watchful and
are equipped to defend against any kind of threat towards them or their
offspring. During the nesting season, the owls regularly defend their nests
against arctic foxes, corvids and swift-flying jaegers; as well as dogs, gray
wolves and avian predators. Males defend the nest by standing guard nearby
while the female incubates the eggs and broods the young. Both sexes attack
approaching predators, dive-bombing them and engaging in distraction displays
to draw the predator away from a nest. They also compete directly for lemmings
and other prey with several predators, including Rough-legged Hawks, Golden
Eagles, Peregrine Falcons, Gyrfalcons, jaegers, Glaucous Gulls, Short-eared
Owls, Great Horned Owls, Eurasian Eagle Owls, Common Ravens, wolves, arctic
foxes, and ermine. They are normally dominant over other raptors although may
(sometimes fatally) lose in conflicts to large raptors such as other Bubo owls,
Golden Eagles and the smaller but much faster Peregrine Falcons. Some species
nesting near Snowy Owl nests, such as the Snow Goose, seem to benefit from the
incidental protection of snowy owls that drive competing predators out of the
area.
Info courtesy of Wikipedia
