Another tough winter for northern Minnesota deer
For the sixth winter out of the past 10, deep snow means severe winter.
DULUTH — If you think you have a hankering for spring to actually arrive soon and stick around, imagine being a white-tailed doe in the northwoods.
It’s been since October or longer since she’s had anything nutritious to eat, and her fat reserves are down to little or nothing. If she did manage to get pregnant last fall, there’s a good chance that fawn won’t be born alive, or she may have just one instead of the usual two. She’s still trudging through snow 2 feet deep and more in some areas. And now wolves are walking on top of crusted snow to chase her as she punches through with each step.
As the News Tribune first reported in February, this is now the sixth winter out of the past 10 that has been unusually snowy in parts of northern Minnesota, a string not seen since the 1970s, and the sixth year of the past 10 when the Department of Natural Resources winter severity index will rocket into the severe category for large swaths of the Northland.
The longer winter hangs on, and this one is hanging on long, the worse it gets for the deer that can’t begin to truly recover until green growth sprouts in spring.
“Wolf activity was prevalent and field patrols note that the snow has crusted over, making for ideal hunting for these predators” to catch deer, said conservation officer Troy Fondie, who patrols the woods and waters around Orr, in his weekly report. “Another winter storm on the horizon this week would further stress the deer herd.”
Deer numbers can rebound fast if given a string of several mild or even normal winters in a row. That happened after several brutal winters in the 1990s, when a string of very mild winters in the early 2000s led to all-time record high deer numbers, even as wolves also thrived. But that hasn’t happened lately.
Repeatedly snowy winters have prevented Arrowhead region deer numbers from rebounding over the past decade. It’s the deep snow that is the hardest for white-tailed deer to deal with. Unlike moose, with longer legs, deer didn’t evolve to live this far north where snow gets this deep; they only moved into the region after logging and fires a century ago.
The DNR’s winter severity index awards one point for every day when temperatures get below zero and one point for every day with 15 inches or more snow on the ground. Winters with a total winter severity value of 50 or lower are considered mild — as occurred nearly statewide last winter — with 51 to 119 moderate and 120 or higher considered severe.
Studies show about 10% of deer die during a normal winter in the northwoods, and mortality goes up — in some cases to 40% and more — as the snow piles up and the winter severity index increases.
Many areas of northern Minnesota have already pushed above 120 and into the severe range. Many other areas (those areas of pinks and purples on the winter severity map) are approaching severe and will likely get there unless a rapid warmup and melt occurs in the next week.
Parts of Cook and Lake counties, while not considered prime deer range, still have 3 feet of snow on the ground as March transitions to April. Severe-category snow depths (the darkest colors on the map) also already exist in parts of St. Louis, Itasca, Koochiching, Lake of the Woods, Clearwater, Roseau, Cass and Hubbard counties.
According to DNR wildlife experts, deep snow often pushes deer to migrate from their usual home ranges to winter ranges — called yarding-up — where they concentrate in relatively small areas at higher numbers, often in areas of thick conifer tree cover. That can help them avoid deep snow but it also quickly reduces available food, and that concentration of deer often attracts wolves.
Areas with a winter severity index in the severe range can expect to again see reduced deer hunting options in 2022, such as bucks-only seasons or few if any antlerless permits issued. Even areas with moderate winter severity index readings could expect to see fewer antlerless permits available as the DNR works to rebuild the herd with its primary management tool: how many deer that hunters kill each autumn.
Wildlife experts note that areas with agricultural fields offer a quicker snowmelt and faster green-up and will allow more deer to survive even severe winters compared to deep forest areas.
John Myers reports on the outdoors, natural resources and environment for the Duluth News Tribune. He can be reached at firstname.lastname@example.org.