Preliminary harvest figures from last fall's deer hunt indicate Minnesota's whitetail population is growing.

Department of Natural Resources wildlife managers had expected the herd to rebound after back-to-back recent tough winters, combined with what many observers believe were too many antlerless permits issued to hunters by the DNR.

At the DNR Roundtable last Friday, with about 300 invited stakeholders attending, big game coordinator Adam Murkowski said the preliminary 2016 statewide deer harvest was 171,026, a 7 percent increase from the 2013-2015 harvest average of 157,972.

The past two relatively mild winters have aided the recovery.

The size of the deer harvest can vary year to year, in part because the number of antlerless permits issued by the DNR varies. But the 2016 harvest increase wasn't because of a rise in the antlerless kill, which was 70,565, almost exactly the same as the 2013-15 average.

Instead, a substantially larger statewide buck harvest — which rose 12 percent — was recorded last year. Which is good news, because the buck harvest is a reasonably good indicator of the size of the overall herd.

The buck kill last fall was 100,461, compared to the 2013-15 average of 87,908. (The recent low was 81,036 in 2014.)

Whether the apparent increase in herd size will continue in the near term depends in large part on the weather this winter. If snow isn't too deep, particularly up north, and the cold not too severe, it's likely the herd will at least stabilize, and probably increase.

Here's a look at the 2016 deer kill, broken down by region.

• In Zone 1, generally the forested north, the total harvest was up 12 percent, while bucks killed jumped 19 percent. The antlerless harvest dropped 8 percent.

• In Zone 2, the total harvest rose 6 percent, while bucks killed increased 9 percent and the antlerless kill was essentially flat, at a 2 percent increase.

• In Zone 3, in the southeast, where chronic wasting disease has been found in five deer, the harvest tracked somewhat differently. Overall kill in the southeast fell 3 percent last fall, while the buck kill was up 2 percent and the antlerless harvest down 7 percent.

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In the three zones are 128 "deer permit areas." In 40 of these areas covering generally the east-central part of the state and along the North Shore, deer population goals were set in recent years following DNR-arranged meetings with hunters and others.

In five of the areas, the groups decided to stabilize deer numbers; in 22 areas, the goal was to increase the deer count 25 percent; and in 13 areas, population hikes of 50 percent were sought.

Murkowski said Friday that according to preliminary 2016 harvest figures, 20 of the 40 deer-permit areas remained under goal; nine were at goal; and 11 were over goal.

Of course, certainties are few when counting deer, and most such "counts" are estimates determined by computer modeling. These are backed up by aerial surveys when possible.

DNR researchers have recently developed a new way of deer modeling called the "stochastic model," replacing its former "deterministic" model.

In both, the number of deer harvested, bucks in particular, in given permit areas helps gauge a model's general accuracy over time. DNR wildlife research director Lou Cornicelli explains:

"If, for example, hunters harvest 1,000 deer a year in an area for five years, there cannot be a sustaining population of only 2,000 deer in that area [regardless of what a model might say]. The area would simply run out of deer. The population range should be somewhere between say 4,000 and 6,000.

"Fewer than that and the observed harvest [especially antlered bucks] would decline dramatically. More than that and the observed harvest would significantly increase over time.

"The same logic applies to density estimates. Let's say hunters harvest five deer per square mile in an area every year. You cannot have seven to 10 deer per square mile with that harvest level, there simply has to be more deer to support that level of harvest."

Bottom line: Deer harvest numbers are an important indicator of deer populations, and the increased 2016 harvest suggests strongly that the state's herd is on the upswing.

Dennis Anderson • danderson@startribune.com