DNR releases updated Wisconsin gray wolf population estimate

The gray wolf in Wisconsin and most other states has been protected under the federal Endangered Species Act since February 2022.

Wisconsin had an estimated 1,226 gray wolves in 336 packs in late winter 2025, according to the Department of Natural Resources.

The 2025 population estimate represented a slight decline from the previous two years and suggests the state’s wolf population is reaching an equilibrium around its biological carrying capacity, said Lydia Margenau, DNR wildlife research scientist.

The DNR released the data Sept. 11 at the inaugural meeting of its Wolf Advisory Committee in Marshfield. The 2025 wolf monitoring report covers April 15, 2024 through April 14, 2025.

The agency produces an annual report on wolves in the state, partly as a requirement to the U.S. Fish and Wildlife Service. The gray wolf in Wisconsin and most other states has been protected under the federal Endangered Species Act since February 2022.

A map shows gray wolf densities in Wisconsin in 2024-25, with most wolves in the northern and central forest regions. (Department of Natural Resources via Reuters Connect)

Since 2020 the DNR has used an occupancy model in its work to produce a wolf population estimate. The model requires inputs from wolf tracking surveys conducted by agency staff, volunteers and others as well as data obtained from GPS-collared wolves.

The GPS collar data helps the scientists determine wolf territory sizes and movements. The DNR obtains data from the collared animals via satellite.

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The state’s annual wolf report reflects the species’ status in late winter when the population is at its annual low point and is easiest to track and monitor. Wolf populations typically double after pups are born in spring then drop due to various sources of mortality, according to wolf researchers.

Due to poor tracking conditions and a higher than normal failure rate of GPS tracking collars, the 2024 report did not have a minimum wolf count or population estimate for the species.

The agency switched suppliers of the collars and had better success last winter, said Danielle Deming, DNR assistant wolf biologist. The DNR is monitoring 41 wolves statewide with active GPS collars, about twice as many as a year ago.

Over the last five years, the Wisconsin wolf population estimates were 1,175 in 2021, 985 in 2022, 1,277 in 2023, 1,328 in 2024 and 1,226 in 2025, according to the DNR’s 2025 Wisconsin wolf monitoring report.

The number of packs over the same time period were 305, 296, 363, 354 and 336, respectively.

The 2024-25 wolf monitoring report included a record high 18,426 miles of tracking effort and at least three tracking outings in all 144 survey blocks, according to the DNR.

The DNR monitors wolves across six management zones. Zone-specific pack size estimates in 2025 ranged from a high of 4.12  wolves per pack in Zone 1 to a low of 2.87 in Zone 4.

For comparison, the previous year’s mean pack size estimates ranged from a high of 4.22 wolves per pack in Zone 1 to a low of 2.68 in Zone 4. The year-over-year pack size differences were not significantly different, according to the DNR.

The average wolf territory size was 54 square miles in most of the state’s wolf range (wolf management zones 1 to 4), but a more condensed 33 square miles in the central forest region (Zone 5).

The DNR documented 36 wolf mortalities (including collared and non-collared wolves) during the monitoring period. Sources of mortality included 19 (53%) wolves killed by vehicle collisions, 12 (33%) wolves killed illegally, four (14%) wolves died of natural causes, and one (6%) cause of death could not be determined. Two of the wolves that died from natural causes were euthanized because of disease; one tested positive for canine parvovirus and the other canine distemper.

Law enforcement efforts recovered 11 wolves killed illegally during the monitoring period. Conservation wardens conducted 15 wolf-related investigations, issued five citations and three verbal warnings, according to the DNR.

Wolves are native to Wisconsin but were wiped out by the late 1960s through unregulated hunting, poisoning and bounties. The state had a bounty on wolves until 1957.

The species suffered the same fate in Michigan but significantly a population of wolves survived in northern Minnesota and Ontario.

After wolves began to receive more protections, including through the Endangered Species Act in 1973, some of the animals began to disperse from northern Minnesota and recolonized Wisconsin and the Upper Peninsula of Michigan, according to wolf researchers.

The population of wolves in Minnesota was estimated at 2,911 in 2023 according to the Minnesota Department of Natural Resources and the minimum count of wolves was 762 in 2024 in the UP of Michigan, according to the Michigan Department of Natural Resources.

The 2025 Wisconsin report included 57 verified (44 confirmed and 13 probable) incidents of wolf depredation to livestock and 13 verified (11 confirmed and 2 probable) incidents of wolf harassment to livestock on 40 farms. Twenty-nine of the farms are classified as chronic wolf depredation farms, or sites with verified wolf depredation in two or more years in the past five-year period.

Most wolf depredations on livestock occurred during the months of May, August and September.

Wolves were also responsible for killing 27 dogs and injuring nine during hunting activities, mostly hounds during the black bear training or hunting seasons, and killing two pet dogs apart from hunting, according to the DNR.

The report also cited two incidents classified as human health and safety conflicts. Both involved wolves observed multiple times during daylight hours near occupied dwellings and human activity. The wolves were behaving in a non-habituated and non-aggressive manner, according to the DNR. Non-lethal abatement and increased vigilance were recommended abatement in both incidents.

Since wolves in Wisconsin and most states are protected by the federal Endangered Species Act, lethal control measures cannot be used on the animals.

No wolf attack on a human has been confirmed in Wisconsin in modern history, according to the DNR.

Bills that seek to remove wolves in Wisconsin and other states from Endangered Species Act protection have been introduced in Congress but have not been voted on by the full House and Senate. The USFWS, too, is pursuing an appeal of the 2022 federal district court decision that placed the wolf under ESA protections.

If an effort to restore the wolf to state management succeeds, the DNR will be required by Wisconsin law to hold a wolf hunting and trapping season.

To view the 2025 Wisconsin wolf monitoring report, visit dnr.wi.gov.

This story was updated to add more information.

This article originally appeared on Milwaukee Journal Sentinel: DNR releases updated Wisconsin wolf population estimate

Reporting by Paul A. Smith, Milwaukee Journal Sentinel / Milwaukee Journal Sentinel

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