(Ryan Brady photo) Boreal owls usually live in the deep forests of northern Canada but appear to have come south this year into Minnesota in what is termed an “irruption,” a bird movement usually driven by a lack of food in their normal range. These small owls are being seen in good numbers along Lake Superior in Minnesota and had turned up in the eastern Upper Peninsula this past fall, raising the prospects they could wander into the region yet this winter.

What has been a lackluster season so far for winter birds may see some special visitors from Canada’s northern forests after all.

Reports indicate boreal owls have turned up in good numbers along Lake Superior in Minnesota, raising the possibility they could follow the lake into Wisconsin and the Upper Peninsula.

These diminutive owls are similar to the northern saw-whets that do occur naturally year-round in the northern states and mountains, as well as southern Canada. But the boreal is slightly larger, with a darker and more distinct border around a grayish-white facial disc, according to Cornell Lab of Ornithology’s All About Birds, www.allaboutbirds.org.

As the name implies, they’re a bird of the deep northern conifer forests, both in North America and Eurasia, ranging from ocean to ocean.

They’re normally rare this far south. But some winters see an influx — termed an “irruption” — that usually is triggered by a lack of prey.

This appears to be one of those winters.

The Eastern Upper Peninsula birding update — posted Thursday by Elliot Nelson, Michigan Sea Grant, Michigan State University Extension — reported that “this fall showed record numbers of these small owls showing up at owl banders’ nets and being seen and heard around Whitefish Point for a few weeks.”

So they’ve turned up to the east — though Nelson states no confirmed sightings have been made so far this winter — and to the west.

Normally difficult to see because of their small size and nocturnal habits, these owls have even been active during the day along the Lake Superior shoreline in Minnesota, Nelson said, adding this again may indicate food has been scarce or the birds need extra resources.

Ryan Brady, a Wisconsin Department of Natural Resources conservation biologist based in Ashland, took note of the boreal owl bonanza as well in a Facebook post earlier this week, writing the species is “staging their biggest irruption here in a couple decades.”

He added, “Large numbers were banded at fall research stations and now dozens are being seen in Minnesota north of Duluth. Fortunately for birders, the owls have become diurnal, presenting an opportunity to view them. Unfortunately for the birds, this behavior in this species usually indicates they’re pretty hungry.”

Brady wrote that while no boreal owls have been reported in Wisconsin yet this winter, he suspects they’re in the state. “Reports often increase as winter rolls on, so I expect the first any time now, especially if we get some snow cover.”

The boreals do have one habit that might help in seeing them, too, Brady said: “Bird feeders regularly attract boreal owls as they hunt the mice, voles and flying squirrels eating there.”

He also advised listening for scolding chickadees that might be mobbing an owl in a stand of spruce, fir or other conifers.

The other tantalizing potential prospect from the Great White North is great gray owls. But that could be more of a stretch, Brady advised, as “they don’t like to cross the big lake, so look for those in northwestern Wisconsin counties this early in the season.”

The great gray is at the other end of the owl spectrum from the boreal. It is North America’s largest owl in terms of height, though much of that is feathers and it is outweighed by both the snowy and great horned owls. Despite its size, its diet primarily is small mammals, mostly voles and mice.

Like the boreal, great gray owls are present in the northern forests of Europe and Asia as well.

Brady wrote of the great gray this season, “There is a strong possibility these birds are in the area, but are easily missed due to their nature of spending time in dense wooded areas and their amazing camouflage.”

Nelson advised, “Search for these owls by checking the edge of spruce and aspen forests near small bog openings, roadside ditches, and along the edge of smaller fields. Great gray owls are adverse to spending time in large open fields, and prefer dense tree cover nearby or directly where they are hunting. Also note they are nocturnal so checking around dawn and dusk are the best chances for success.”

One last note on the EUP report: Snowy owls numbers appear to be far better than last winter, which was very low, Nelson said.

His full EUP birding update can be viewed at https://www.canr.msu.edu/news/eastern-upper-peninsula-birding-update-what-to-see-and-where-msg24-nelson24.

Perhaps we’ll get lucky enough to have one of these special owls turn up in the region. If you see something unusual, please let me know.

Betsy Bloom can be reached at 906-774-2772, ext. 240, or bbloom@ironmountaindailynews.com.