SNOWY OWLS ARE a mystery in many ways. In some years, great numbers come south from the Arctic to reside in fields, farmlands, and shorelines. In other years, we see very few. People have long wondered where they come from and why.
In the past, it was believed that population crashes of lemmings on the owls’ breeding grounds caused many owls to come south. But their movements are more complex and unpredictable than that—they are affected by weather, availability of prey, and breeding success. The years that we see many owls in the south actually seem to be the result of an abundance of lemmings. This owl food can lead to fantastic breeding success and throngs of hungry young owls. Many may be driven southward by competition with more dominant adult owls.
Each nomadic owl is on a lifelong journey spanning continents, in search of food. Individuals have been tracked moving from Alaska to the Canadian Arctic to Russia over the course of just a couple of years. Some wander the pack ice, hundreds of miles from land, where they feed in Arctic darkness on seabirds that they snatch from the water with their hooked talons.
When one of these Arctic wanderers comes south to reside in a farmer’s field, we get to glimpse a moment in a long journey that we as humans can hardly imagine.