Snowy owls come south in unpredictable invasions known as ‘irruptions.’ It’s mostly about food and babies, but we have a lot to learn about this phenomenon.
Snowy owl migration is complex; some birds migrate south predictably and regularly, while others remain on the breeding grounds or actually move north, onto the Arctic sea ice, hunting in perpetual winter darkness. But every once in a while, for reasons that are not fully understood, snowy owls come flooding down from the north in a phenomenon known as an irruption.
Smaller irruptions happen, on average, every four or five years, but once or twice in a lifetime a mega-irruption occurs, when snowy owls show up much farther south, and in vastly greater numbers, than usual.
The winter of 2013-14 was one such extraordinary event, the largest irruption in the Northeast and Great Lakes regions perhaps a century. Snowy owls were reported as far south as Florida and Bermuda. In 2014-15, another sizeable irruption… more