First snowy owls of the season being spotted in Wisconsin. Here's what to know.

There's a chance of snow in parts of Wisconsin this week.

But the season's first gifts of the Arctic, documented and true, are already in the state.

Four snowy owls have been seen and photographed in recent days in the Badger State, according to the Department of Natural Resources.

Brian Lukens of Wausau was among those to see and capture images of one of the handsome birds near Wausau.

Lukens, who works as a manufacturing supervisor and is also a highly skilled wildlife photographer, spent most of Sunday looking for a snowy or other birds in central Wisconsin, including at Buena Vista State Wildlife Area near Plover.

He said he "struck out" during the day, but driving home after sunset he almost hit a snowy owl on a road near Wausau.

"(The snowy owl) was on the ground off to the side of the road and a bicyclist went past and flushed it," Lukens said. "It flew across the road and very nearly flew into my windshield."

He was able to relocate the bird Monday morning near Wausau and captured still images and video of it, including a stunning photo of the bird skimming low over water. Lukens saw the bird make two such passes.

Snowy owls primarily hunt rodents but are also known to prey on waterfowl.

The bird is among the vanguard of an annual movement of snowy owls south from the Arctic. Some years feature an "irruption" that can bring more than 100 snowies to Wisconsin. Other years the number is far lower.

The coming weeks will tell the tale of the winter of 2024-25.

What is a snowy owl?

Snowy owls are an owl species with white or white-and-black plumage. They are the heaviest owl in North America, with an average weight of 4 pounds. They are about 23 inches long and have an average wingspan of 52 inches, according to the Sibley Guide to Birds.

Snowy owls are predominantly birds of the Arctic and can be found spanning the region from the northernmost sections of the U.S. and Canada to Scandinavia and Russia.

Snowy owls nest on the Arctic tundra, often on a slight rise where wind keeps the ground free of snow. In years when the species' primary summer food source - lemmings - is high, snowies may raise 10 or more chicks per nest.

Though they spend most of their lives in the Arctic, in late fall and winter some snowy owls travel south.

What is an irruption?

Although they breed and spend most of their lives on the treeless tundra above the Arctic Circle, each late fall and winter some snowy owls fly south into southern Canada and the northern United States. At least a few reach Wisconsin each year.

Every handful of years, however, large numbers move into the state, an event known as an "irruption." Irruptions also occur periodically with other northern bird species, including the red crossbill, common redpoll, hoary redpoll, evening grosbeak and pine siskin.

One of the largest snowy owl irruptions in recent history was the winter of 2017-18, when 280 of the big birds were documented in Wisconsin, according to DNR data.

It's not known with certainty what causes a snowy owl irruption, but the leading hypothesis links the movement to years with abundant prey and high nesting success. If prey is plentiful around nesting sites and lots of owls are fledged (sometimes as many as 10 per nest), the thinking goes, it increases competition among snowies for resources in the Arctic and causes more birds than normal to fly south.

How many snowy owls were in Wisconsin last winter?

Ryan Brady, DNR conservation biologist, tracks the number of snowy owl sightings in Wisconsin each year. For the winter of 2023-24 he tallied 24 individual snowy owls in the state, the lowest number in the last decade.

For comparison, in 2022-23 36 snowies were documented in the state, but 140 were recorded in 2021-22 and more than 200 in the big irruption years of 2013, 2014, and 2017.

The numbers sighted in Wisconsin over the last two winters suggested poor years of breeding productivity in the Arctic, Brady said.

How many snowy owls are in Wisconsin so far this season?

This year four snowies have been documented in Wisconsin, Brady said. Small numbers of the species are also being reported in the northeastern U.S. and Canada.

"It will be interesting to see what happens when more seasonably cold weather sets in soon, but I am not expecting a big flight," Brady said. "Our last irruption was 2021-22. If the approximately four- to five-year cycle holds up – and that’s a big if – then next year or the year after should see a higher pulse of birds."

Snowy owl viewing etiquette

Snowy owls are vulnerable and photographers and viewers should give them plenty of space. If you cause the owl to constantly look at you or to flush or reposition, you are too close. If you see one, it's best to stay in a vehicle and use it as a blind.

Project SNOWstorm, a crowdfunded study of snowy owls, issued the following guidelines for viewing snowies: keep your distance, respect private property and never feed an owl.

This article originally appeared on Milwaukee Journal Sentinel: First snowy owls of the season being spotted in Wisconsin