Snowy owls are returning to Wisconsin in large numbers for the second straight year.
State Department of Natural Resources research scientist Ryan Brady said approximately 239 different owls have been reported statewide, compared to 224 as of this date last year. Both totals are far above average.
“Many Wisconsinites recall the winter of 2013-14 as one of the best on record, so it’s surprising that we are seeing similar or even slightly better numbers this winter,” said Brady, who also serves as bird monitoring coordinator for the Wisconsin Bird Conservation Initiative. “We usually see one irruption event every three to five years, but Wisconsin has experienced three in the past four winters.”
According to Brady, the reason for these periodic influxes into the state – also known as irruptions – is not well known. Traditional thought suggested a temporary shortage of the owl’s primary prey in the Canadian arctic, a mouse-like rodent known as a lemming, pushed owls southward.
However, more recent evidence suggests nearly the opposite. It is believed an abundance of lemmings may allow birds to raise large families. These young owls then disperse southward into the region by the hundreds.
Snowy owls face many challenges and a significant proportion of them, especially young ones, will not survive. Primary mortality factors include collisions with vehicles, electrocution, secondary rodenticide poisoning, disease and illegal shooting.
However, snowy owls in Wisconsin tend to fare no more poorly than other avian visitors.
“A common myth is that the majority of these birds are facing an uphill battle in an unfamiliar landscape,” Brady said. “However, decades of data and experience indicate this is not true.”
Many snowy owls find exactly what they need in Wisconsin and neighboring states and generally seek out open habitats similar to the arctic tundra they call home. Common habitats include coastal beaches and harbors, open grasslands and agricultural fields, wetland complexes, airports and vast expanses of ice-covered water bodies. Snowy owls are not adverse to civilization and are often found in suburban or even urban settings.
Given their preference for lemmings in the arctic, owls in Wisconsin tend to focus on voles, mice, shrews and other small rodents for food. Snowy owls are also known to pursue rabbits, weasels, pigeons, and ducks.
Snowy owls are showing up in nonforested areas of the state. Hotspots include airports and farm country from Green Bay to Appleton; the Collins Marsh State Wildlife Area; the State Highway 29 corridor between Wausau and Eau Claire; the Horicon Marsh; and the Antigo, Superior, Dunn County, and Milwaukee lakefront areas.
Brady said there are certainly new birds to be found and all suitable habitats are worth exploring.
While snowy owls can be seen during the day, the dawn and dusk periods often provide a better chance of success. Interested bird watchers are encouraged to explore area roads and all potential perches carefully, including hay bales, fence posts, telephone poles, breakwalls, silos and other buildings.
“In many cases, you may not be the only person to see an owl and the cumulative impacts of these actions can be especially harmful,” Brady said. “If, for example, you flush an owl trying to get a photo and another person comes along and does the same, that owl has wasted precious energy and will be less equipped to survive.”
Snowy owls are expected to maintain their Wisconsin residence through March before beginning their northward migration back to arctic Canada.
“These are magical creatures, stunning in appearance, unpredictable, mysterious and the epitome of wild,” Brady said. “I may never visit their remote haunts thousands of miles to the north, but seeing one here brings a sliver of that wilderness to me.”