Want to see a snowy owl? This could be your winter

This could be an unusually good year to spot snowy owls in southern Canada. 

This past weekend, the Owl Foundation, an owl rehabilitation centre based in Ontario's Niagara region, reported in a Facebook post that it had already admitted two young snowy owls so far this year, suggesting that it's "shaping up to be a snowy owl irruption year!"

An irruption is a surge in the local population of a species, for example, an unusual number of snowy owls coming south from the Arctic. So far this year, more young snowy owls have been reported earlier than usual in southern Canada and the northern U.S., and researchers say this it might mean an opportunity to see a relatively rare visitor from the North that was recently labelled threatened by the Committee on the Status of Endangered Wildlife in Canada.

Brian Hayhoe, a wildlife biologist and rehabilitator at the Owl Foundation, wrote the post. He says in the past few winters, the centre has received zero to two snowy owls each year, often not until December or January.

He's heard from other wildlife centres in other parts of Ontario that are also reporting higher numbers earlier than usual, and said they're often the first to notice trends like this: "Rehabbers are kind of like the canary in the coal mine."

Meanwhile, two snowy owls have recently drawn crowds near Chicago, also prompting suggestions of an irruption year.

Scott Weidensaul, a researcher involved with the snowy owl GPS tracking program Project SNOWstorm, says most southern snowy owl sightings so far have been in the central and western Great Lakes and in the Prairies. But there have been a few spotted as far west as B.C., where they've rarely been seen in recent years.

"Maybe it's going to shape up to be a decent year out there as well," Weidensaul said.

An irruption is a large movement of birds that happens periodically — unlike a migration, which happens regularly, such as from a northern region to a southern region every fall. 

With snowy owls, an irruption often brings them south in large numbers about every six years, says Guy Fitzgérald, a veterinarian who specializes in wild birds of prey at the Faculty of Veterinary Medicine at the Université de Montréal and is part of the Project SNOWstorm team.

There are reports of irruptions in 2017-2018 and 2020-2021. But Weidensaul says the biggest in recent history was in 2013-2014 when "there were literally thousands of snowy owls that came down from the subarctic."

Fitzgérald says that in the past decade, peaks in snowy owl numbers haven't been as obvious as in the past. "This may be a sign that something is wrong in their breeding area in the north."

Nicolas Lecomte is a Université de Moncton professor who's part of a team that's been tracking and studying snowy owls for 25 years and collaborates with Project SNOWstorm.

He says irruptions tend to happen in years when lemmings — an important food for snowy owls — are abundant in the Arctic. In those years, snowy owls produce many more chicks than usual and there can be hundreds of nests in a very small area.