Snowy owls

by Lisa Ralls
Winnebago County Naturalist
Each winter, birds that typically live much further north venture south in search of food. Many of these birds are small songbirds such as juncos, siskins, red-breasted nuthatches, redpolls, purple finches, and tree sparrows. But, some are larger, including snowy owls. And, this winter, it appears we will see a lot of snowy owls.
Although some snowy owls are looking for food, not all are. Snowy owls spend most of the year in the Arctic, feeding mostly on lemmings, voles, and other small tundra mammals. If populations of these animals are high in the spring, then snowy owls eat well and produce more young. This population explosion then causes many of those birds (usually the younger ones) to head south in the winter in search of their own space, as well as food. That’s called an irruption and it appears that this winter we’ll see an irruption in Iowa.
Most years, that population explosion doesn’t happen and we only see a handful of snowy owls in Iowa. But, during irruption years, as this year is turning out to be, we may see dozens, possibly hundreds, of snowy owls. This year, just since October, we’ve already had at least 50 snowy owl sightings here in Iowa. And the winter is just beginning.
Snowy owls are different than other owls we see in Iowa because they are uniquely adapted to living on the Arctic tundra. They are white to blend in with the Arctic snow and they have very thick feathers to insulate them against the cold Arctic climate. (Those large feathers make the snowy owl the heaviest of all the owls, averaging about 4 pounds.) Unlike other owls, they are diurnal, meaning they are most active during the daytime. Although they can also hunt at night, when you live in an area where days can be almost 24 hours long, it does help to be able to also hunt during the daytime. Another characteristic that distinguishes them from most other owls is that they are very comfortable on the ground. In fact, they even nest on the ground. That’s because on the tundra there are few, if any, trees; so they’ve adapted to living on the ground.
If you spot a snowy owl, you may be surprised that they are often not as white as you may expect them to be. Adult males are often close to pure white, but adult females are usually more spotted. Young birds tend to be very spotted, losing their spots as they get older.
Since snowy owls are Arctic birds, they prefer open landscapes. So, look for them in open fields. They can often be seen perched on a fence post, a telephone pole, or a traffic sign, or sitting on a hay bale, searching for small rodents to eat. Unfortunately, in that search, they sometimes venture too close to highways and get hit by cars. Flying into power lines and eating poisoned rodents on farms are also common causes of death here in Iowa. Some birds also become physically exhausted from the long migration and become too weak to hunt, starving to death.
If you do see a snowy owl, consider yourself lucky. Even in irruption years, they are not a common sight here in Iowa. But, please keep your distance. Snowy owls are not used to people and can be easily disturbed, stressing them out or flushing them into oncoming traffic. Staying in your car and using it as a blind is a good way to safely observe them. Also, don’t feed them to get them to come closer. If you do, they will begin to associate people with food which can be dangerous for the birds.
So, this winter, keep your eyes open for these large, white owls. If you see one, think about how far it has come and enjoy the fact that you’re able to see a little piece of the Arctic right here in Iowa.