A snowy owl is seen at the Leslie Spit in Toronto.
The scene before Bruce Mactavish seemed like something from the pages of Harry Potter or the logs of ancient ship captains: snowy owls, dozens of them, perched on power poles, hilltops and other high points around Cape Race, at the southeastern tip of Newfoundland. It was a full-on invasion, or, in the vernacular of the birding world, an irruption.
"You kind of become a glutton after a while," said Mr. Mactavish, one of Newfoundland's most active birders. "You see so many. It was several times more than I'd ever seen before."
His total count over that single weekend last month: 301 snowy owls, a bird bonanza that quickly became the talk of the birding community as the tale made the rounds on blogs and news sites.
Mr. Mactavish's total could be some kind of record, but it comes in a year when the snowy owl is giving new meaning to the term snow-bird. From the busy runways of Hamilton International Airport to the Canadian Tire Centre in Ottawa to the beaches of Florida and Bermuda, snowy owls have fanned out across the eastern half of the continent in unprecedented numbers.
The boom is bolstering new theories about the species while adding to the mystique of a bird that remains enigmatic despite the powerful new tools birders are using to track them.
All owls are naturally captivating for their round faces and forward-looking eyes – a strangely human countenance – but the popularity of the snowy eclipses its feathery brethren. "They're big and an unearthly white with big yellow eyes. They look so out of place when they're down here," said Pennsylvania-based naturalist and author Scott Weidensaul. "They look like a little chunk of the Arctic has been picked up and dropped in a much more mundane landscape. There's a mystery to them that draws people. And certainly Harry Potter hasn't hurt."
Indeed, you can spot a birder by their irritation with the Harry Potter franchise. In the books, the young wizard's feathered companion, Hedwig, is female. In the movies, Hedwig is clearly played by a male impostor, much to the dismay of the serious birder.
Despite popular interest, the bird's habits remain mysterious. Irruptions like this one happen every 10 to 15 years. Conventional wisdom once held that this parliament of owls was flying far south of their usual winter habitat because populations of their preferred prey, lemmings, had crashed and the birds were starving.
"It turns out the conventional wisdom about these birds is entirely false," Mr. Weidensaul said. "This is not the result of a lack of prey. What we're seeing is the result of an extraordinary abundance of prey this year."
Snowy owls can lay up to 11 eggs in a single brood. In a normal year, two might live long enough to leave the nest. This season, due to the abundance of lemmings, researchers were seeing all the young survive.
Researchers have found that some snowy owls actually migrate north for the winter. They have no preprogrammed migratory pattern like so many of their avian cousins. "They really don't know where they're going," said Mr. Weidensaul, adding that there are historical reports of ship captains being surrounded by white owls in the night.
Mr. Weidensaul and other bird researchers have launched a campaign called Project Snowstorm on the fundraising site Indiegogo to buy GPS transmitters that can be used to track the owl's winter movements. The researchers are closing in on their goal of raising $20,000 to get 20 to 25 transmitters working in a variety of habitats before the irruption ends.
A few new tools have already taken some of the mystery out of the raptor's erratic travels. The website ebird.org, run by the Lab of Ornithology at Cornell University, offers a central spot where avid birders can report the species they've seen. With some 200,000 participants submitting checklists, Ebird serves as an up-to-the-minute map of what species are where. Combine that with the bird alerts some clubs send out as text messages or e-mails and a birder's cellphone becomes just as much a tool of the trade as binoculars, telephoto lens and Tilley hat.
During high birding season at Ontario's Point Pelee National Park, it's not uncommon to see birders walking trails with smartphones at the ready, heading in the direction of the latest online tip.
"With Internet community aspect, so many more people can go out and see these birds," said tour guide and birder Bruce Di Labio, who recently spotted a snowy atop the Canadian Tire Centre, home of the Ottawa Senators. "With the snowy owls, especially, you can watch them for hours. And this is the perfect year, with numbers we've never seen before."
Snowy owls might appear unperturbed by human spectators, but birding organizations advise members to resist getting too close. A good rule is to back off if a bird begins staring at you, according to the U.S. National Audubon Society.
And now the bad news. Most of the snowy owls currently wandering from their Arctic habitat are juveniles and will not last long. Like many bird species, snowy owls have a 60- to 70-per-cent mortality rate before their first birthday, according to bird experts.
Yet they have a knack for survival, as illustrated at Hamilton International Airport on Tuesday. Mike Thornton, a cargo plane pilot, was taxiing to the end of a runway when he noticed four snowy owls watching him from the edge of the tarmac. They flew off when his noisy Beech 1900 rumbled past, but as he turned and reached takeoff speed, one of the owls swooped down and settled on the runway directly ahead.
"Oh no," Mr. Thornton said to himself, knowing a bird of that size – anywhere up to 2.9 kilograms – would do significant damage.
"Luckily he heard us coming and went straight up, so I made a shallower takeoff to miss him," Mr. Thornton said. "I would have felt really bad. My dad is a big bird watcher. It'll probably make his day when I tell him about this. I've never seen a bunch of them like that before."