Yellowstone wolf population rebounds from hunter harvest

BILLINGS– The wolf population in Yellowstone National Park has rebounded somewhat following a reduction in 2021-22 when hunters killed 25 animals that primarily lived inside the refuge where hunting is banned.

By the end of last hunting season, the park had 80 wolves before pups were born.

This December, thanks in part to a reduced wolf hunting quota in Montana, the park population grew to 108 wolves in 10 packs with seven breeding pairs. Pups made up more than a third of the total Yellowstone wolf population.

“I think what that shows us is this species is really resilient,” said Dan Stahler, lead wolf biologist for the park.

New pups should be venturing outside their dens soon, providing wolf watchers with high-powered spotting scopes, cameras and binoculars a chance to watch them play, wrestle and explore their new environment.

Yellowstone’s more thorough wolf program report for 2022, with information on each pack, will be released online within the next few months.

Hunting

Wolves are hunted in the three states surrounding Yellowstone – Montana, Wyoming and Idaho.

In 2021, the Montana Fish and Wildlife Commission increased the wolf-hunting quota in two hunting districts near Yellowstone’s northern border.

The change resulted in 19 wolves, which spent much of their life inside the park, being killed in Montana. In Wyoming, four wolves were killed, one of which was poached. In Idaho, two wolves were shot.

Prior to the quota change, Montana officials had limited the wolf hunt outside the park’s northern boundary to two wolves, one in each of the two bordering hunting districts.

With a new Fish and Wildlife Commission at the helm, Montana also changed the statewide limit to 20 wolves each hunter could take, 10 by trapping and 10 by hunting, up from a limit of five. Bait and night hunting were also allowed on private land.

Before the changes, Yellowstone officials noted hunting resulted in an average of 4.3 park-associated wolves killed each season in all three states.

Reduced quota

Following calls for Montana to lower the quota near the park, the Montana Fish and Wildlife Commission reduced the wolf quota to six in Hunting District 313 north of the park, which combined two the former units – HD 313 and 316.

Wolf advocates had argued the live animals in Yellowstone benefited gateway communities through tourism and travel spending to the tune of around $82 million.

This past hunting season (2022-23), the new quota was filled by hunters taking four of the six wolves that were known to be associated with Yellowstone. Two were from the Rescue Creek pack, one-collared adult male from the 8 Mile pack and one collared-adult female from the Junction Butte pack.

Another known park wolf was killed in a different hunting area in Montana. In addition, two other known-Yellowstone wolves were killed by hunters in Idaho and Wyoming.

Hunters aren’t the only reason Yellowstone wolves die.

Inside Yellowstone, four wolves were killed by other wolves – the leading cause of wolf deaths inside the park – and another was dispatched by a bear. Another wolf was hit by a vehicle and one died of natural causes for a total of seven wolf deaths.

State hunts

Montana’s statewide quota for wolves this season remained 450, with 258 killed by hunters and trappers.

That was the second year of decline in the wolf harvest in Montana, despite laws enacted by the Legislature to increase wolf deaths.

In neighboring Wyoming, 95 wolf mortalities were recorded in 2022 – 53 in the Wolf Trophy Game Management Area surrounding Yellowstone and 33 outside the area where wolves are considered a predator.

Two were killed on the Wind River Reservation. (Yellowstone’s seven wolf mortalities are counted toward Wyoming’s total as well.)

“Twenty-one wolves were lethally and legally removed by agencies or the public in an effort to reduce livestock losses to wolves (15 in the WTGMA, six in predatory animal areas in WYO),” the Wyoming Game and Fish Department reported. “Wolves were confirmed to have killed or injured 97 head of livestock.”

In January, the Idaho Department of Fish and Game reported 234 wolf mortalities in 2022.

The population there declined by 13% from the previous year’s for a total population estimate of 1,337 animals. Idaho has also increased hunting and trapping opportunities in an attempt to drive the state’s wolf population down to around 500 animals.

Two packs concentrated on Yellowstone’s Northern Range suffered the heaviest losses in the 2021-2022 hunting season – eight wolves in the Junction Butte pack were killed and six from the Phantom Lake pack.

The Phantom Lake and Bechler packs dissolved following the hunting season – the Bechler pack lost two wolves. The wolves, however, formed four new packs: Shrimp Lake, Firehole River, Willow Creek and Lupine Creek.

Stahler said the pack changes can’t be specifically tied to 19% of the park’s wolves being killed in 2021-22, although pack dynamics can be affected when alpha wolves die.

Instead, he outlined a combination of factors that could be affecting the park’s wolf population.

Bison as prey

One factor affecting wolf populations is the shifting prey dynamics, with wolves eating more bison.

“One of the interesting patterns here, and I think it’s an important story for the public to understand, is just how important bison have become to Yellowstone wolves, and that pattern continues to this day,” Stahler said.

Over the past few years, as the park’s bison population has grown, wolves have been dining out more often on the large ungulates.

“And it’s not necessarily from predation, although wolves do kill bison adults and young of the year, but a lot of it is from scavenging,” Stahler said.

In the fall, large bull bison may be injured during the August rut and succumb to their wounds. In winter, there’s a natural loss of bison to starvation.

“Wolves are very quick to capitalize on that,” he said.

This winter was particularly harsh, with large numbers of bison migrating out of the park in search of food where hunters were waiting.

More than 1,000 bison were shot or had to be killed by officials after they were wounded.

Some of the bison that didn’t venture out died from the severe conditions that included deep snow and long-lasting cold temperatures.

With more bison on the landscape – the estimate was a population of 6,000 last fall – and more bison deaths, wolves are eating fewer elk.

“That in some ways explains why we have a stabilized Northern Range elk population,” Stahler said. “They don’t have to kill as many when they’re feeding on a lot of bison carcasses.”

As an example, Stahler said Mollie’s pack, which winters in the remote Pelican Valley, benefited from more bison dying from natural causes.

The park monitors the pack every 30 days in the winter. This was the first time in Stahler’s 26 years on the job that the pack didn’t make a single bison kill in March.

That was because there were plenty of winter-killed animals on the landscape.

“That to me was a really fascinating thing,” Stahler said. “Here’s a pack of wolves that didn’t have to go through that difficult and dangerous task of making a kill.”

Young pups

Another factor affecting wolf pack dynamics is a large number of young wolves reaching dispersal age amid several years of successful pup production.

Last spring, at least 58 pups were born, with another three or more litters that died before they could be counted.

Of these, 40 survived to the end of the year – 28 in the five northern packs and 12 in the five interior packs.

Doug Smith, the park’s lead wolf biologist who retired in November after 28 years of leading the program, predicted last year that pup production would increase following the high number of wolf losses.

“One thing I’m worried about is the hunt could stimulate reproduction because it broke up the wolves’ social structure,” he said in an April 2022 interview. “This is well known in coyotes.

“When you have a stable pack, reproduction is controlled by the dominant wolves.”

Hunting for information

When collared wolves are killed, it also means a loss of data collected.

The park attempts to collar at least one wolf in each pack to keep tabs on their movements. This winter’s trapping and collaring was successful with 27 wolves captured, Stahler said.

As an alternative to using collars to track wolves, Stahler said the Wolf Project is studying the use of bioacoustics, which could document wolf howls all day every day.

Similar technology has been used to monitor whales, as well as birds and elephants.

A 2019 study published in the Journal of the Royal Society Interface discussed the increasing deployment of recording devices being used to monitor animals as a noninvasive alternative to techniques like capturing and collaring wildlife.

Brett French can be reached at BFrench@billingsgazette.com