Gray wolf population saw growth outside trophy-game area

Joy Ufford,
Posted 5/6/21

Gray wolves across of Wyoming at the end of 2020 showed growth compared to the year before with higher estimates outside of the state’s trophy-game area.

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Gray wolf population saw growth outside trophy-game area


SUBLETTE COUNTY – Gray wolves across of Wyoming at the end of 2020 showed growth compared to the year before with higher estimates outside of the state’s trophy-game area.

The 2020 annual report “Wyoming Gray Wolf Monitoring and Management” was posted last week on the Wyoming Game and Fish Department’s website.

As of Dec. 21, 2020, Game and Fish estimated at least 327 wolves statewide in at least 44 packs with at least 23 breeding pairs. There were 119 known mortalities. At the end of 2019, at least 311 wolves had been estimated in at least 43 packs with 22 breeding pairs and 96 known wolf mortalities. They are divided into population segments of Yellowstone National Park, the Wind River Reservation, Game and Fish trophy-game management area – and everywhere else, the predatory animal zone.

Yellowstone National Park’s gray wolf numbers grew noticeably; Wind River Reservation’s numbers increased slightly and the state’s predator zone population showed expansion – even with more wolves there removed for livestock conflicts. 


The 2020 report showed an increase to at least 123 wolves in nine packs with seven breeding pairs – the highest population since 2008. In Yellowstone at the end of 2019, at least 94 wolves lived in eight packs with seven breeding pairs.

“This census was the highest since 2008 (124 wolves) and marked a one-year increase of 31 percent after a decade of very little population change year-to-year,” the report says. “Much of the growth was attributed to successful pup production and survival in multiple packs, most notably the Junction Butte pack which produced four litters and raised 18 pups through the end of the year.”

Yellowstone packs ranged from four to 35 wolves with an average of 13. The number of packs and breeding pairs was the same as the average over the last decade. Pack size in 2020 ranged from 4 to 35, averaging 13 compared to a long-term average pack size of nine to 10.

“Again, this average was largely driven by the exceptional size of the Junction Butte pack at 35 members, the report says. “Average pack size not including Junction Butte was 11. Two other packs, 8 Mile and Wapiti Lake, had 21 and 20 members, respectively, making 2020 the only year with three packs of 20 or more members in mid-winter.”

In 2020 at least 60 pups were born, with four other litters that died before they could be counted. Of those counted, 52 or 87 percent survived to Dec. 31, 2020, more so in northern Yellowstone National Park than the interior. The pups made up 42 percent of the park population, compared to the last decade’s average of 32 percent.

The younger wolves were easier to catch and collar, according to the report, with nine pups, four yearlings, one 2-year-old adult and one estimated at 1 to 3 years old. Biologists also measured the newly collared wolves and took biological samples. 

Wind River Reservation

Wolves first “recolonized” the reservation in 2003 and the population has grown slowly, ranging from 10 to 20 a year.

As of Dec. 31, 2020, at least 21 wolves were in three packs with two breeding pairs along the eastern from of the Wind River Range. Two wolves were seen in the Owl Creek in January, according to the report. In 2019, there were 16 wolves, three packs and one breeding pair.

The reservation opened its first trophy-game wolf hunt from Dec. 1, 2020, through Feb. 28, with a quota of six wolves in two hunt areas of the Wind River and Owl Creek mountain ranges – none were taken and none were killed to protect life or property in 2020. There were no livestock conflicts reported last year either. 

Predator area

As of Dec. 31, 2020, there were at least 36 wolves in at least eight packs, and at least two breeding pairs in the predatory animal areas including seasonal trophy-game area. Last year, Game and Fish estimated at least 26 wolves in five or more packs.

Game and Fish does not manage the predatory animal area where a wolf can be taken at any time. USDA’s Wildlife Services caught and collared six wolves by the end of 2020, taking genetic samples to test for diversity, the report says.

The known numbers grew in the predator area even after 43 mortalities were recorded – 22 were taken by hunters and 16 by Wildlife Services, the report says. Also, three died by human causes, two from natural causes and one “unknown.”

The high number of lethal takes by WS resulted from three conflicts with cattle and one with sheep in and around southern Sublette County.


In the Wyoming trophy-game management area, Game and Fish estimated at least 147 wolves in at least 24 packs with at least 11 breeding pairs, compared to 175 wolves in 27 packs in 2019.

The Game and Fish management goal is to have at least 160 wolves in the WTGMA, the report says.

Since hunting seasons reopened in 2017 in the gray wolf trophy-game management area, hunters have taken more wolves than were removed by lethal control. Several deaths through 2020, fewer than 2019, were due to unknown, natural and other human causes.

“The 2020 end of year wolf population in the WTGMA was 8-percent lower than the population objective set during the wolf hunting season setting process – 147 wolves vs. the 160-wolf population objective,” it says. “Wyoming Game and Fish Department wolf management has consistently produced an end-of-year wolf population within 10 percent of the population objective since 2018. The efficacy of the season-setting process employed is dependent on analysis of long-term wolf population trend data for the WTGMA, including recruitment (i.e., breeding pairs) and mortality. The Department will continue to take an adaptive management approach for setting 2021 wolf-hunting seasons as outlined in the Wyoming Gray Wolf Management Plan.”

The 2020 hunting season resulted in only 31 taken against a total quota of 51. Two were taken in early January in Hunt Area 13. Sixteen of 26 packs in the TGMA had wolves harvested; six wolves did not belong to an established pack. Seventeen females and 14 males were taken, with almost twice as many black wolves than gray and more adults and sub-adults taken.

Wyoming Game and Fish sold 2,221 wolf-hunting licenses – 1,848 to residents and 229 to nonresidents. That was up from 2019 sales of 1,885 tags.

“For all wolf-hunting seasons combined, more juveniles and fewer adults have been taken in earlier months with the ratio shifting toward adults through the end of the hunting season in December,” the report says of hunt areas that opened in September.

Livestock conflicts

“The total number of wolf-livestock conflicts in 2020 was higher compared to 2019 largely due to increased sheep and chicken depredations. The number of cattle killed by wolves was similar to the two previous years.”

In 2020, wolves were responsible for killing or injuring 51 cattle (41 calves and 10 cows/yearlings), 12 sheep, one dog and 10 chickens. In response, Game and Fish issued 21 lethal-take permits with 13 wolves killed by the end of 2020. Thirteen more were removed in agency-directed lethal control. One was killed in defense of private property.

In livestock conflicts, 32 cattle and 23 sheep were on public land and 19 cattle, 10 chickens and one dog were on private land. Game and Fish compensated $152,860 to 20 livestock producers with confirmed kills last year. In 2019, compensation was $106,183.

“Compensation payments have consistently remained lower under Wyoming Game and Fish Department management from 2018-2020,” the report says.

To read the entire report, go to