Window on Nature
By Lowell & Kaye Christie, F47246
Have you ever seen a snowy owl in the wild? We haven’t; we try to stay out of the snow. We wouldn’t count it among our “life” birds, but we have seen one on the silver screen in the movie Harry Potter and the Prisoner of Azkaban. Harry is a little confused, though. He thinks his pet snowy owl is female, when the owl actor is clearly male. How do we know? The plumage of female snowy owls is two-toned “” white barred with brown. The male has the all-white plumage with little ticks of brown.
Snowy owls weigh more than any other North American owls. They measure two feet tall when standing and have a four-foot wingspan. The heads of snowy owls are smooth and rounded, with no visible ear tufts like those of the familiar great horned owl. The legs and feet of a snowy owl are covered with feathers all the way to the talons, and they need it.
Snowy owls are adapted to frigid climates, such as the tundra and grasslands of far northern Canada, Europe, and Asia. And while they are predators, they also are preyed upon. Wearing a white feather coat makes them harder to see.
Many birds migrate as the season changes. Warblers head south in the fall and return when the weather grows warmer, as do ducks, geese, hawks, and snowbirds. So do snowy owls. They breed and raise their chicks on the edge of the continent “” the northern parts of Alaska, Canada, Greenland, and also the far north of Europe and Asia.
On our continent, moving south for the winter means traveling to central and southern Canada, and, in lesser numbers, to the adjoining border states of the United States. The adult females stay farther north, while young males tend to move farther south.
It was long believed that the owl’s southernmost migrations were periodic, timed to a cyclical drop in their preferred prey, lemmings. However, recent analyses of bird count records show that the number of snowy owls wintering in the United States lacks a discernible reason or pattern.
Whether they come for the warmth, a better selection of food, or because of a venturous spirit, snowy owls occasionally have been sighted as far south as central California, southern Nevada, Utah, Colorado, Oklahoma, central and southeastern Texas, the Gulf States, and the Caribbean.
Unlike most other owls, snowy owls feed in daylight. After all, when the Arctic “day” is 24 hours long, they have no choice. Their main prey may be lemmings, but they also enjoy snowshoe hares, mice, and voles. And they aren’t above grabbing ducks, geese, or ptarmigan (think of it as an Arctic grouse) while flying. They must eat an adequate diet, in that snowy owls can live up to nine years in the wild, and as many as 35 years in captivity.
Courtship and breeding season begins in late March or April. But it isn’t until May that the females start laying a clutch of five to 14 eggs at a rate of one every other day. As with other birds, the size of a snowy owl’s clutch depends on the area food supply. Her body tells her when to stop laying eggs and begin incubating them.
For the 32 to 34 days of incubation, the male owl provides food for his mate, and then for the chicks. The young stay in the nest for two to four weeks after hatching. They’ll be flying by the time they reach 7 weeks old.
Here are a few general facts about owls that you might find interesting. Owls mate for life. Only if one spouse dies does the surviving bird look for another mate. Owls have three eyelids with three purposes “” one eyelid is designed for blinking, the second for sleeping, and the third for cleaning the eye surface.
Most owls have the ability to swivel their heads nearly three-quarters of the way around without moving their bodies. That’s a good thing, since owls can’t move their eyes in the sockets. Some owls have one ear set higher on their head than the other. This provides excellent triangulation to pinpoint the location of their next meal. Owl feathers are specially designed to muffle the sound of their flying, allowing them to sneak up on prey. Finally, owls are extremely helpful to humans, because they keep the rodent population under control.
Now back to snowy owls. You aren’t likely to see or hear a snowy owl while it is flying. They rarely “speak” except during breeding season. When the male owl gives a loud “hoo!” he’s being territorial, telling other males to stay off his turf. He uses the same sound as a mating call to any female close enough to hear. Snowy females rarely hoot, but when excited, either sex may burst out with a loud “hooo-uh, hooo-uh, hooo-uh, wuh-wuh-wuh.” Luckily for those who identify birds by their calls, the voice of each of the 19 owl species in North America tends to be distinctly different from the others.
Since the snowy owl is diurnal, it can hunt using the “sit and wait” technique. It simply selects a perch with a good view and stands there. Because the bird can swivel its neck 270 degrees in either direction, it spots prey easily. Once dinner is found, the snowy owl takes to the air. When it’s within range, the owl sinks its talons into the back of the animal and begins backflapping until the prey is too exhausted to resist. The same technique works on fish in shallow water. If the prey is small enough, the owl will swallow it whole. If it’s too big to gulp, the bird carries it to a perch and commences to dine there.
After a meal, the owl produces large cylindrical pellets containing the indigestible portions of its prey “” bones, feathers, etc. These it expels (spits out) onto the ground. And given that a snowy owl has to eat the equivalent of seven to 12 mice every day to meet its dietary needs, the presence of many pellets means a snowy owl must be nearby.