This winter has brought an unprecedented number of snowy owls south of their normal habitat. The unusual migration, known as an irruption, has been a thrill for bird watchers in the Eastern United States. Snowy owls typically live near the arctic circle, but this winter have been spotted in New York, Rhode Island and even as far south as South Carolina. "An irruption like this probably hasn’t happened in 30 years or more,” ornithologist Peter Paton told the Providence Journal.
Some think the owls have come south in search of food, such as lemmings and other rodents. The Audubon Society’s Mark Martell told CBS Minnesota that the food shortages occur roughly every six to ten years. "So when the population (of Lemmings) crashes, now you’ve got all of these owls with no food left, so they move south looking for food," he said.
Kevin McGowan of Cornell University's Lab of Ornithology offers two possible explanations:
"One is that they have a very high success rate in breeding this year over last year. The parents tend to jostle them out of the nest," McGowan said. "The opposite possibility is that the normal food sources are disrupted and they have to travel farther south to find their food."
Audubon writer Kenn Kaufman explains that there's still a lot of uncertainty:
"This season's invasion so far has been concentrated farther east than the last one, along the Atlantic Coast and the eastern Great Lakes, with smaller numbers farther west. We don't have a complete answer for why this is happening. But we do know that lemmings (the owls' favorite prey in summer) were abundant in northern Quebec last summer, and the owls apparently had very good breeding success there. Elsewhere in the Arctic, including farther west, it wasn't such a productive season. So northern Quebec could be the source for much of this season's flight. From that region, if the birds headed south, they would wind up concentrated exactly where they are being seen this year."
Snowy owls can often be spotted during the day, because they've adapted to survive in regions where there is continuous sunlight during parts of the year.
Have you seen a snowy owl this winter? We'd love to hear about it in the comments section.