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DNR deer aging survey reveals healthy local herd, more data needed

“Most people would look at that buck and say, ‘It’s starting to get palmate antlers so that’s probably a 4- or 5-year-old deer.’ We had a hard time determining whether it was 2-½ or 3-½ years old based on the amount of herbage the deer had been eating. We look at the cusps on the back three molars. They are starting to tilt toward the outside indicating it is a 3-½ year old deer,” explained Halvorsen. (Photo by Tom Lindfors)1 / 2
(Submitted photos)2 / 2

Deer hunting in Wisconsin is big business.

According to a survey completed in 2006, hunters spent $665 million directly on hunting-related expenditures including items such as licenses, firearms, ammo, gas for the pickup, food and beverages, lodging and land access fees for the nine-day gun hunt.

The ripple effect on the larger economy equated to roughly $1.03 billion.

That’s the economic picture, but what about the hunt’s impact on the biology of the deer population?

The Wisconsin Department of Natural Resources (DNR) website provides a table with the overall harvest information going back to 1966, a period of 48 years.

For the purposes of this discussion, we will be looking at the data from just the nine-day gun hunt.

In the first year on record, 1966, 432,111 hunters killed a total of 110,062 deer.

A further review of the data shows in 1971, 509,447 hunters took 70,875 deer, the lowest number of deer taken by gun hunters over that 48-year period.

In 2000, 694,712 gun hunters took 528,494, the highest number on record.

Over those 48 years, the average number of hunters each year works out to be 634,461 and the average number of deer taken works out to 253,870.

The most recent count for the 2015 nine-day gun hunt stands at 201,812. The total number of gun hunt licenses sold through the end of the gun deer hunt season in 2015 was 608,711.

According to the DNR’s comparison of opening weekend success, this season’s kill was roughly 1 percent lower in Polk County than in 2014, 5 percent lower in St. Croix County and .6 percent higher in Pierce County.

Biologist not too concerned

Wildlife biologist Harvey Halvorsen works out of the DNR office in Baldwin. He spent a morning with RiverTowns Media taking a closer look at what the 2015 hunt yielded locally.

“When you are talking about thousands of deer and you have a 5 percent or 10 percent  change in numbers, that is within an (acceptable) biological limit. I don’t get too concerned. I use the term ‘plastic’ to describe the deer herd in Wisconsin.  There is a high level of flexibility in the population as long as we have that doe base. In a year or two, you are going to see a tremendous herd resurgence. Taking into account the winter severity, the quality of the habitat, the amount of thermal, hiding cover out there, we have a very healthy deer population,” Halvorsen said.

In 2014, the DNR consolidated what had been 134 separate deer management units (DMU) across the state into 72, making each county into its own DMU. 

2015 was the first year hunters were required to register their deer online. Traditionally, hunters had brought their deer to a designated registration station where the deer were physically registered. That gave DNR personnel an opportunity to “age” the deer in person and speak with hunters directly.

“That was the magic of the entire deer aging process taking place at a registration station. Our professional wildlife field staff are more than just deer biologists and you saw them in action. Whether it was a water quality issue with beavers or deer eating the browse or the apple trees, our biologists were willing to share from their cornucopia of knowledge with people as they came in, be they happy or be they disgruntled. We tried to treat everybody fairly,” Halvorsen said.

The 2016 online registration process required the DNR to engineer a new way to acquire their deer hunt data.

“We still need to get aging data so we that we can maintain our population models,” Halvorsen said.

That data contributes a large portion of the information the DNR uses to interpret the health and density of the deer population in the state.

“We backtrack and use the data from the past to predict the deer herd model for the future,”Halvorsen said. “We take into consideration the structure, age, birth rate, recruitment rate and mortality rate. That gives us a model to then build into our future population growth projections. Highly, highly accurate. That allows us to set the antlerless quota. Everything we do pertains to the antlerless quota in the state of Wisconsin, because that’s where our fawn production comes from.”

Working with processors

This year, the DNR worked with three local deer processors in St. Croix and Pierce counties each, to collect the heads of butchered deer to conduct the aging survey. Processors were paid $2 per head. A tag indicating which county or DMU the deer had been shot in was attached to each head.

DNR personnel gathered at the Baldwin building to conduct the survey Dec. 2. The survey determines the sex of the deer, its age, where and when it was harvested and what type of zone (forest or farmland) from which it came. 

“We always look at the lower jaw, usually just one side unless there is a question, then we’ll look at both sides. We are looking at the deer’s dentition, in particular the wear on the back three molars. We do not test for CWD. Most of the deer are 3 ½ years and younger. We had one 12-plus-year-old doe come through our aging process this year, very rare,’ Halvorsen said.

The survey says

Thirty-three counties were represented in the 741 deer surveyed at Baldwin on Dec. 2.

St. Croix County: (1) doe 12-plus years, (1) doe 9-12 years, (29) female fawns, (29) does 1 year, (35) does 2 years, (13) does 3 years, (3) does 4 years, (37) male fawns, (54) bucks 1 year, (10) bucks 2 years, (7) bucks 3 years - Total 219

Polk County: (3) does 6-8 years, (12) female fawns, (23) does 1 year, (8) does 2 years, (12) does 3 years, (7) does 4 years,

(16) male fawns, (23) bucks 1 year, (3) bucks 2 years, (3) bucks 3 years, (2) bucks 4 years. - Total 112

Pierce County: (1) doe 9-12 years, (1) doe 6-8 years, (24) female fawns, (19) does 1 year, (23) does 2 years, (8) does 3 years, (1) doe 4 years, (29) male fawns, (30) bucks 1 year, (17) bucks 2 years, (2) bucks 3 years - Total 155

Many hunters are surprised to learn how young their deer are.

Halvorsen points to the mount of a nice buck on his office wall. 

“Most people would look at that buck and say, ‘It’s starting to get palmate antlers so that’s probably a 4- or 5-year-old deer.’ We had a hard time determining whether it was 2 1/2  or 3 1/2 years old based on the amount of herbage the deer had been eating. Because there was not a lot of siliceous content, not a lot of sandy materials to grind down those molars, they stayed sharp longer. We look at the cusps on the back three molars. They are starting to tilt toward the outside indicating it is a 3 1/2-year-old deer,” Halvorsen said.

One of the challenges the DNR faces going forward with the new online registration system will be getting enough representative deer to age.

The old physical registration at stations typically yielded 200-300 deer per-station.  

“We’d like at least 150 mature bucks for each DMU,”  Halvorsen said.

Getting enough deer particularly from “metropolitan” units has always been a challenge because there is not as much public land to hunt, so more of the hunt takes place on private lands. Private lands tend to have fewer hunters, so less pressure and that tends to produce older deer which can skew the survey.

All of this science is shared with the County Deer Advisory Councils (CDAC).

“On Feb. 16, we will be meeting as a region with our deer statistician from Madison to review the status of the population based on the current county DMU’s to try to figure out what we are doing successfully and where we might have to tweak our population goals. All of this date evolves into a timeline for projecting how many antlerless deer we want to kill next year. Those numbers have to be approved by the CDACs, followed by a public review and then approval by the Natural Resources Board before it becomes law for next season. Overall our goal is to make sure the public’s concerns and interests are included in our deer management plan and to provide each hunter with a safe, quality deer hunting experience.”

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