This will come as no surprise: It’s been an easy winter.
That’s good news for Minnesota’s deer population, especially across northern counties, where Department of Natural Resources biologists are hoping the population will recover from a series of harsh winters.
The DNR’s Winter Severity Index readings, computed from daily snow depth and temperature readings, are lower than 50 in every deer management unit in the state, according to the agency. End-of-season values of less than 100 are considered a mild winter. Readings higher than 180 indicate a severe winter.
Each day with a snow depth of more than 15 inches adds a point to the WSI reading, as does each day during which the temperature drops to zero or below.
“Deer are doing very well this winter,” said Tom Rusch, DNR area wildlife manager at Tower. “Their movement is generally not restricted by snow depth.”
In the seven deer management units that Rusch’s territory includes, WSI values range from 13 to 31, he said.
DNR wildlife biologists say snow depth is the more critical factor in the WSI index. Snow depths range from 10 to 20 inches across the Tower DNR work area. Snow depths exceed 24 inches only in a band along the North Shore in Cook County, according to National Oceanic and Atmospheric Administration maps.
“I sure don’t expect many more days below zero,” said Dave Olfelt, DNR regional wildlife manager at Grand Rapids. “Our expectation is that deer are going to come out of the winter in good condition. That will help to recover the deer herd for sure.”
With moderate snow depths, deer can range more easily.
“Deer are distributed much wider, utilizing available food sources, compared to recent severe winters,” Rusch said.
Even in International Falls, a community that hangs its hat on cold weather, the winter has been very mild, said DNR area wildlife manager Larry Petersen.
“Certainly, it’s looking good,” Petersen said. “As of the end of January, we have the second-lowest WSI index since the winter of 1965-66.”
Snow depth is about 8 to 11 inches, Petersen said.
“I’ll take this winter,” he said. “The deer are moving quite nicely through this snow. Where I live, the deer usually leave, but this year they’re just hanging around.”
Minnesota’s statewide deer harvest following the severe winter of 2013-14 was just 140,000, the lowest since the early 1980s. Last fall’s overall harvest in Series 100 permit areas (including Northeastern Minnesota) was up about 11 percent, according to the DNR. The buck harvest, generally considered the most reliable population indicator, was up 18 percent across Series 100 units, according to the DNR.
For the past two deer seasons, the DNR has issued few antlerless deer permits in Northeastern Minnesota in an effort to conserve does and let the deer herd rebound.
After back-to-back severe winters in the mid-1990s, a series of mild winters allowed the deer herd to recover rapidly.
“That’s what needs to happen here,” Petersen said.
After an average to mild winter last year across Northeastern Minnesota, fawn production was good last spring, DNR wildlife managers said. If this winter continues to be mild, the same could happen again this spring. Fawns born after mild winters, when does typically are in better shape, tend to fare better, Petersen said.
“If it’s good for mom, it’s good for junior,” he said. “We should see the results of that in upcoming years.”
Wisconsin faring well
Wisconsin has been having an equally mild winter, said Greg Kessler, DNR wildlife biologist at Brule. WSI readings are low in Northwestern Wisconsin, he said.
“Brule is at 10 and Barnes is at 13 on Feb. 1,” Kessler said. “So far, this equates to high survival — about 95 percent — of the existing herd and high fawning rates next spring. While there is a lot of winter left, deer are in excellent condition with no reports of dead deer yet and many bucks still carrying their antlers. Given that we are typically past the coldest part of winter, there is an excellent chance we will see moderate to good herd growth this year.”
Wisconsin’s WSI is computed slightly differently from Minnesota’s, accumulating one point per day for temperatures below zero and one point for snow depths of more than 18 inches.