Snowy Owl Irruption
Your chances of seeing a snowy owl are better this winter than they’ve perhaps ever been. We are in the middle of an irruption (the migration of large numbers of birds to areas where they aren’t typically found) of snowy owls. There are several reasons for irruptions, the most common being a lack of food in the birds’ normal wintering grounds. When there is a seed crop failure (birch, maple, pine, spruce and hemlock) further north, we often are inundated in the winter with seed-eating songbirds that typically overwinter in Canada, including waxwings, redpolls and grosbeaks, among others. Birds of prey typically irrupt at this time as well, for when the seed crop fails, the (seed-eating) population of rodents also crashes, driving rodent-eating raptors further south to find food. Snowy owls dine primarily on small rodents called lemmings, so one would expect from the current irruption that the Canadian lemming population must have crashed. However, the opposite appears to be true this winter. Arctic researchers report that this year lemmings were at historical population highs allowing for a very successful breeding season for Arctic raptors, including snowy owls. The resulting population boom caused overcrowding and competition at typical wintering grounds, resulting in our current banner snowy owl winter.
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