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Serving Northern St. Louis County, Minnesota

DNR: Wolf population increases 25 percent

Growth in deer herd appears to be biggest factor behind the gain

Marshall Helmberger
Posted 9/27/17

REGIONAL— The recovery of northern Minnesota’s deer population has provided good news for hunters, of both the human and canine variety.

That’s the finding from the latest survey of northern …

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DNR: Wolf population increases 25 percent

Growth in deer herd appears to be biggest factor behind the gain

Posted

REGIONAL— The recovery of northern Minnesota’s deer population has provided good news for hunters, of both the human and canine variety.

That’s the finding from the latest survey of northern Minnesota’s wolf population, which shows a 25-percent increase since the last survey, conducted in 2015-2016.

The wolf population had been holding roughly stable in several prior surveys, but showed a significant jump in just the past year. “From approximately 2005 to 2014, a decline in prey appears to have translated into larger wolf pack territories, fewer or smaller packs and a reduced wolf population,” said John Erb, a DNR biologist who studies the state’s wolf population. “Now, the reverse appears to be happening.”

The 2016-17 survey, the results of which the DNR released this week, estimates that approximately 500 wolf packs operate within the state’s wolf range, comprising 2,856 wolves. The survey’s margin of error is about plus or minus 500 wolves. The 2015-16 survey estimated 439 packs and an overall wolf population of 2,278.

The latest numbers are well above the state’s minimum goal of at least 1,600 wolves and also above the federal recovery goal of 1,251 to 1,400. The DNR has consistently managed wolf populations at levels that exceed both state and federal minimums.

Survey results suggest packs, on average, are slightly larger (4.8 vs. 4.4 animals) than in the recent past and are using smaller territories (54 square miles vs. 62 square miles) than the previous winter. Although neither statistic individually represented a significant change from recent years, collectively they explain the increase in the population estimate and are consistent with a continuing increase in deer numbers observed in many parts of wolf range. From spring 2015 to spring 2016, deer density within the wolf range is estimated to have increased 22 percent.

While other factors such as pack competition, disease, and human-caused mortality can influence the wolf population, prey density typically determines the carrying capacity for wolves.

“Changes in estimated wolf abundance generally have tracked those of deer over the past five years,” Erb said. At the same time, the state’s annual wolf season has been suspended since a 2014 federal court decision that found that the U.S. Fish and Wildlife Service had been “arbitrary and capricious” when it removed the gray wolf from the Endangered Species Act, opening the door to the wolf season. Hunters and trappers in Minnesota harvested somewhere between 250 and 400 wolves annually under the season.

The wolf population survey is conducted in mid-winter near the low point of the annual population cycle. A winter survey makes counting pack size from a plane more accurate because the forest canopy is reduced and snow makes it easier to spot darker shapes on the ground.

Pack counts during winter are assumed to represent minimum estimates given the challenges with detecting all members of a pack together at the same time. A winter count also excludes the population spike that occurs each spring when the number of wolves typically doubles immediately following the birth of pups, many of which do not survive to the following winter.

Visit the DNR website at mndnr.gov/wolves to find the full population survey report.