Two weeks after the state of Montana decided Yellowstone bison could roam year-round in the area outside West Yellowstone, an interagency group decided almost 1,000 bison needed to be killed this winter.

Members of the Interagency Bison Management Plan decided once again that 600 to 900 bison needed to be eliminated from the herds of Yellowstone National Park to reduce the population below the 4,900 estimated to reside in the park.

Bison can be killed either by hunters or through capture operations at the park’s Stevens Creek bison trap near Gardiner. The hunt is already going on, but the Stevens Creek facility won’t begin operations until Feb. 15 and could operate until March 31. Any bison trapped at Stevens Creek will be sent to the Confederated Salish and Kootenai Tribes for slaughter to provide food for tribal members.

However, there’s no guarantee that many bison will die. Both the bison trap and bison hunters depend on hard, snowy winters to move bison out of the park.

Last winter, the IBMP partners hoped to kill 900, but due to the mild winter, only two-thirds were eliminated. If El Nino weather predictions hold true, this winter may also not drive enough bison down. The resulting bison population can put more stress on park habitat.

“Many people are uncomfortable with the practice of culling bison, including the National Park Service,” says Yellowstone National Park Superintendent Dan Wenk. “The park would gladly reduce the frequency and magnitude of these operations if migrating bison had access to more habitat outside the park or there was a way to transfer live bison elsewhere.” 

Livestock producers oppose efforts to expand bison distribution into Montana, because bison compete with cows for forage and some bison carry the disease brucellosis, which in rare instances can be transferred to cattle and make cows abort their calves. However, no bison has caused any brucellosis outbreak in Montana cattle.

The old IBMP plan written in 2000 set a target population in the park of about 3,000 animals. Montana livestock producers often argue that the park should strictly adhere to that population target to keep more animals from migrating out.

This year, there’s added political pressure to bring the bison population down as a result of a new expanded bison area near West Yellowstone.

On Dec. 22, Gov. Steve Bullock announced that for the first time, bison would be allowed to remain in Montana year-round, at least during a two-year pilot study.

Near West Yellowstone, they could wander more than 255,000 acres of public lands from Hebgen Lake north to the Taylor Fork of the Gallatin River and over to the crest of the Madison Range. North of Gardiner, bull bison could roam the Gardiner basin north to Yankee Jim Canyon year-round, because bulls don’t spread brucellosis. The disease can only be spread through direct contact with the aborted calves of cattle, elk or bison.

Bison can’t go south of Hebgen and West Yellowstone under the governor’s plan, but that could change in the future if supported by adaptive management.

“This decision is a very modest expansion of the conditions under which bison may remain outside of the Park, in response to changing science and changing circumstances on the ground. While at the same time, I am confident our livestock industry is protected,” Bullock said.

Bullock’s delayed decision was the final part of a public process that took three years to hammer out.

Under current policy, bison are allowed to wander only in less than 38,000 acres near Horse Butte on Hebgen Lake and only until around May 15. After that, Montana Department of Livestock riders haze bison back into the park presumably to keep them from coming in contact with cattle.

Slowly, more people began to question this spring ritual because most residents around West Yellowstone didn’t mind bison hanging around, they didn’t like riders hazing the bison, and fewer area landowners owned cattle.

In July 2013, the Montana Fish, Wildlife and Parks and the DOL released an environmental assessment of six alternatives, including one, Alternative B, where bison could roam up in to 280,000 acres.

The environmental assessment received more than 100,000 public comments and the vast majority favored Alternative B.

But in May 2014, the Montana Board of Livestock opposed allowing any bison out if the park population exceeded the 3,000-bison target. So a seventh alternative was developed in November 2014 where bison could stay in Montana only if their population stayed down near 3,000.

Since then, bison advocates have waited for the governor’s decision.

Bullock may take some heat from livestock interests because his proposed pilot project doesn’t tie bison range to the park population. So Bullock made it clear that he would “pressure the Park Service to reduce the bison population in the Park, and keep those numbers to manageable levels.”

The IBMP must still approve the governor’s proposal before it goes into effect. In the meantime, the cull will go on.