“Something Huge Is Going On”
Snowy owls are the some of the largest birds in North America, but scientists know very little about their behavior. The owls spend most of their days far from humans, hunting rodents and birds in the flat expanses of the arctic circle. In the winter the owls shift south, but they don’t usually reach United States. Most years, only a few are spotted in the northernmost states — an rare treat for birders. But this year was different.
Owls started to appear all over the United States right around Thanksgiving — in Nebraska, in Kentucky — even as far south as Georgia. Dave Brinker, a biologist with the Maryland Department of Natural Resources, was shocked when he saw not one but two snowy owls on the dunes of Assateague Island.
“Something huge is going on,” Brinker told his colleagues. “We won’t see something like this for a long time — probably for the rest of our lifetimes.”
This rapid population boom — called an “irruption” by ecologists — is the largest the East Coast has seen in forty or fifty years.
The Trigger (Lemmings!)
So what caused the irruption? This picture tells the story:
It shows a snowy owl’s nest that was photographed by biologists last summer in northern Quebec. Those furry lumps are the carcasses of 70 lemmings. Lemmings — small, hamster-like rodents — are the main source of food for snowy owls in the arctic. Thanks to the abundance of lemmings last summer, well-fed mother owls laid more eggs, and huge numbers of owlets grew up fat and strong. Come winter, they spread far to the south.
read more: http://wuwm.com/post/years-snowy-owl-invasion-was-good-news-scientists