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By Paul A. Smith
Gray wolves have increased to a record level in Wisconsin, yet white-tailed deer populations in northern Wisconsin are also increasing. The trends help point out that human hunting and severe winter weather are the primary drivers of deer populations in Wisconsin.
When it comes to gray wolves and white-tailed deer, there are enough deep-seated beliefs to fill the Dells of the Wisconsin River.
Some of them, like many of the acts in the nearby town, are based more on fiction than fact.—
Here’s one: The wolves are killing all the deer in northern Wisconsin.
It’s not a new refrain, but it’s one I continue to hear from some of my hunting colleagues each year.
Now in late summer 2017, as bucks begin to lose their velvet and wolf pups start to venture out more with adults, conditions are ripe to discuss trends in both species.
In a word, both are “up.”
There are 480,273 deer in the 18-county northern forest management zone, according to the 2017 pre-hunt population estimate from the Department of Natural Resources.
The 2017 number represents an 18% year-over-year increase.
The population of wolves, as you may know, is at an all-time high in Wisconsin. The DNR in June reported a record high of at least 925 wolves, most of which are in northern Wisconsin.
The latest wolf report represents a 6% increase from 2015-’16 and a 24% rise from 2014-’15.
So the two iconic wildlife species have been increasing in number across Wisconsin’s Northwoods.
Why? And how can it be? If wolves are at an all-time high – and if they “eat all the deer” – shouldn’t the deer herd at least be falling?
A look at the data and management related to each species can be illuminating.
The wolf population has increased largely due to a December 2014 federal judge’s decision that placed the western Great Lakes population under protections of the Endangered Species Act. The ruling has prevented state officials from holding public hunting and trapping seasons or using other lethal means to manage the species.
Deer have been increasing partly due to protection, too. For the last several years, the number of antlerless deer permits has been significantly reduced in northern units. Some counties have allowed zero.
With more female deer allowed to live and reproduce, the population assumed an upward trajectory.
Mother Nature is the other primary factor allowing deer herd growth in the north. The last three years have been marked by “soft” winters, including the fourth (2015-’16) and sixth (2016-’17) mildest on record since 1960, according to the DNR’s Winter Severity Index.
In contrast, two very rough winters took a toll on the deer herd in 2011-’12 and 2012-’13. The 2011-’12 winter was the third most severe on record; the following year was especially tough on deer since winter conditions lasted into May.
The milder winters have been reflected in recent years in higher fawn-doe ratios and a higher proportion of yearling bucks with forked antlers, according to DNR big game ecologist Kevin Wallenfang.
Another factor – habitat – likely has improved marginally in northern Wisconsin in recent years due to some changes in forestry practices. But it’s harder to quantify and likely takes longer to show its effects on the deer herd.
I find the status of both species particularly interesting now, as wolf numbers have climbed to a record high.
Wolves obviously eat deer. According to most experts, an adult wolf will consume the equivalent of 20 adult-sized deer annually.
But when compared to other sources of deer mortality in Wisconsin, wolves rank down the list.
I ran the numbers and trends past David Mech, senior research scientist with the U.S. Geological Survey in St. Paul, Minn. Mech has studied wolves for 59 years and is considered an expert on the species and its effect on plant and animal communities.
“Under these current Wisconsin regulations and conditions, wolves are apparently not a competitor, or aren’t really having that much of an impact (on deer),” Mech said.
The leading causes of deer mortality in the state, as Wisconsin wildlife managers have long said, are human hunters and severe winters.
A 2009 DNR document ranked the deer kill in Wisconsin’s northern and central forest regions this way: 122,000 deer killed by hunters (bow and gun), about 50,000 due to winter stress (the range could vary widely), 33,000 to black bears, 16,000 to coyotes, 13,000 to motor vehicles, 13,000 to wolves and 6,000 to bobcats.
The trends over the last few years in northern Wisconsin are clear.
When I was in Bayfield and Sawyer counties in May for the Governors Fishing Opener, I counted 72 deer on an evening drive from Cable to Hayward.
The conditions reminded me of the plethora of deer I used to see in the area in the mid to late 1990s.
Wolves are up in number. Deer are too.
Humans and Mother Nature have far more control over deer populations than wolves ever will.
I’m hoping my hunting buddies read this. But as always, I’ll be happy to tell them in person.
Pass it along to your friends, too.
As we move forward with management plans on both species, it’s important to bring as many facts to the debate as possible.