“In the winter 2013-14, an invasion of Arctic snowy owls occurred. They were moving south in record numbers, many of them taking up residence in airports. Driven by a search for food, the birds were appearing in large numbers in central and eastern Canada and the American northeast.
Experts aren’t sure what’s causing this “irruption,” a term used when birds migrate outside their normal range. But there are likely two reasons: There may have been a collapse in the Arctic lemming population — a favourite food source — or a boom during the last (Snowy Owl) breeding season that has increased competition for food.” (Isabel Teotonio, Living reporter, THE STAR, Published on Fri Jan 03 2014)