March 1, 2019 at 4:42 p.m.
Deep February snow tough on deer herd
Deep February snow tough on deer herd
By Jacob Friede-
It's also been rough on the deer herd.
The deep snow not only covers up food on the ground, but it requires a lot of energy for deer to move through, and, according to Dr. Daniel Storm, a natural resource scientist and winter severity index spokesperson at the Department of Natural Resources service center in Rhinelander, the energy expenditure is what is most costly to deer.
"Right now, obviously the snow is quite deep, and that's definitely taxing on deer," Storm said. "Deep snow really increases the amount of energy it takes to get around. Anybody that walks in the woods can see that. The more energy they have to use then the more that pulls from their fat reserves. Every summer and fall they build up their fat reserves and then every winter and into spring, they're using up their fat reserves."
Deer depend on their fat to make it through tough times when food is scarce, therefore fawns, who have little amounts of fat are hit the hardest by winter.
"They have to put their energy towards growing and storing fat, where as you have an adult that is more or less done growing they can put more of their energy into storing fat," Storm said. "An adult deer is going to enter the winter fatter than a fawn. The fawns really get hit hard."
In addition to their low levels of fat, fawns also have shorter legs, meaning they have to expend more energy to get around. Being shorter also means they can't reach certain food.
"From the standpoint of winter killing prime age adult deer, not a huge concern," Storm said. "It's those young of the year type deer. Those are the ones that are going to feel it the most for sure."
To track how severe the winter is the DNR uses a Winter Severity Index.
The index is a compilation of weather data collected by the DNR and volunteers at various stations across the north.
"For each day they'll mark down the low temperature and the snow depth," Storm said. "We keep track especially of the days where the low temperatures are zero degrees or below and/or in addition to whether the snow depth is 18 inches or deeper."
A point is given on each day that drops to zero and another point is giving if there are 18 inches of snow or more on the ground. The maximum points that can be accumulated are two a day.
As of January, the Woodruff and Trout Lake stations had reported 14 points for zero degree temperatures and no points for extreme snow. Eagle River had 19 points for low temperature and no points for deep snow.
The February numbers are not in yet, but Storm says the heavy snow and frigid temperatures that occurred last month will only add severity points.
"Given that we're not done with February yet, I don't have the numbers because they're not in yet," Storm said earlier this week. "All across the north what we're going to see is having accrued a lot of these winter severity points. It's hard to see and predict the future. Are we going to end up with what we consider a severe winter for deer, or not, probably, but not certainly."
Storm says the main factor in whether this will be a severe winter is how long it lasts because the more cold days with deep snow on the ground increase the index scores. If an early thaw occurs in March and April, the overall severity of the winter will drop.
"It's really hard to say exactly where we'll end up," Storm said. "The only thing we can say confidently is that we won't end up with calling this winter a mild one."
February numbers should be out within the first couple weeks of March and can be viewed on the DNR website at dnr.wi.gov..
Jacob Friede may be reached at [email protected] or [email protected].
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