Critters of North Idaho: Snowy Owl

If you’re taking a winter hike, you might be surprised who you run into. The snowy owl is probably one of the last birds you’d expect to see. After all, they’re well-known to inhabit the far north. Nevertheless, in some years they can be found far south of their usual range.

They’re frequently spotted as far south as the northern plains in America, and northern China and the Japanese island of Sakhalin in Asia. They are even known to appear in the northern United States, including the Idaho Panhandle. And on very rare occasions, these arctic birds show up in Texas and Florida! Fossils of these birds from the Ice Age have been found even farther south than that, in the Tropic of Cancer.

What are these adventurous birds doing so far south?

Before we answer that question, let’s see who these birds are, shall we? As you probably guessed, the snowy owl (Bubo scandiacus) is closely related to other members of the owl family. So close, in fact, that a male snowy owl and a female Eurasian eagle-owl were bred in captivity in 2013 and gave birth to hybrids, affectionately known as a “Schnuhus” (a cross between the German words for its parents’ species) and both of which grew to maturity.

With a wingspan of about 50 to 57 inches and weighing 56 to 104 ounces, snowy owls are about the size of their other cousins, the great-horned owls.

It’s easy to tell them apart, though, because of their namesake white plumage with black and brown markings. They also lack the ear tufts that their cousins have, and their powerful, taloned feet are covered in feathers to keep them warm in the frigid cold.

Snowy owls are usually found on the tundra. These are the vast, treeless plains of the high arctic. Another thing that distinguishes these birds from other owls, which are nocturnal (active at night), the snowy owl is diurnal (active during the day). This is likely due to the fact that the tundra gets a full 24 hours of sunlight in the summertime, which would make life very difficult for a nocturnal bird.

Since trees are few and far between on the tundra, a mated pair of snowy owls will nest on the ground and hatch between three and 11 hatchlings. The female’s job is to sit on the nest, keeping the eggs warm, while her mate flies around collecting food to feed himself and her.

By now I’m sure the question on your mind is why these birds travel so far south in the wintertime. After all, they’ve got plenty of feathers to keep them from getting cold in the winter, and they’re more than capable of hunting in snowy conditions.

The particularly strange thing about snowy owl migration patterns is that they are irregular. They don’t migrate far south every year, usually every four years or so. And as discussed above, they aren’t very consistent with how far south they go either.

Scientists believe it may have something to do with … food supply! Snowy owls eat a variety of small mammals, like rabbits, seabirds and fish, but one of their favorite sources of prey are lemmings. If you know anything about these mice-like mammals, you’ll be familiar with what is known as their boom and bust cycle.

Each cycle lasts about four years, during which the lemmings run rampant all across the tundra before dying off in great numbers. When lemmings are in short supply, snowy owls must find other sources of food. In doing so, they find themselves flying far south of their Arctic home.

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