Timeline of Yellowstone Bison Management 2011 to 2016

With a near-record population of bison in Yellowstone National Park, park service officials begin culling animals under orders from the State of Montana.
Bison playfully butting heads in the snow

Bison playfully butting heads in the snow

January 13, 2016: With this year’s near-record population of bison in Yellowstone National Park, park service officials plan to cull between 600 to 900 of the animals this winter, reports the Associated Press.

Park officials told the Associated Press the bison will be either hunted or shipped for slaughter. The reason behind the population reduction is to reduce potential conflicts between the park and Montana landowners. During winter, some bison leave the park in search of food, instilling fear in Montana landowners that the bison will transmit brucellosis to their cattle. To date, there have been no recorded instances of wild bison transmitting brucellosis to cattle.

“It’s a numbers game: how many can we accommodate?” Montana State University wildlife researcher Robert Garrott told the Associated Press. “The source population every year will produce 6 to 10 percent (more bison) that will need a new home... Despite the fact that bison are an iconic symbol of the United States and North America once had 30 to 60 millon of them, our society has said there is no place we’re willing to accept them.”

Yet, Yellowstone superintendent Dan Wenk is reportedly optimistic that in the future, hunting could replace slaughtering the park’s bison.

December 22, 2015: Wild bison will be allowed to migrate out of Yellowstone National Park and stay in parts of Montana year-round under a Tuesday move by Gov. Steve Bullock that breaks a longstanding impasse in a wildlife conflict that's dragged on for decades, as reported by ABC News.

The Democratic governor's decision likely won't end the periodic slaughters of some bison that roam outside Yellowstone in search of food at lower elevations. But it for the first time allows hundreds of the animals to linger year-round on an estimated 400 square miles north and west of the park.

Yellowstone has one of the largest wild bison herds remaining in the world. The herds are unique in that they are purebred bison with no cattle DNA. Despite the prestige and protection of this bison population, an ongoing battle between the Yellowstone herds and bordering Montana ranchers has been going on for decades.

Harsh winters in Yellowstone's high country drive bison to more moderate-temperature lower elevations outside the park in Montana. Every year hundreds of Yellowstone bison are shot at or aggressively chased by helicopters and ATVs to get them to turn around and go back into the park. The fear is that wild bison will transmit disease to domestic cattle.

Ranchers are concerned about brucellosis which can be spread by bison, elk and other wildlife. This has been the main focus of heated debates. However there is also a fear of bison competing with cattle for grass on public lands which ranchers have enjoyed at a low cost.

In the year 2000, the Secretaries of Agriculture and Interior, and the Governor of Montana signed a court-mediated agreement to limit the bison population near 3,000. To add to the complexity of the situation, local Native Americans claim that Montana's bison management plan infringes on treaty hunting rights. Historically, regional tribes hunt bison every winter. (See related story: Yellowstone Bison Hunt Takes Record Numbers)

November, 2015: A reported plan for 1,000 bison to be slaughtered this winter, has been softened. It would have been the highest annual kill number in eight years. On Thursday, November 19, 2015, as this premature story of a high projected number of bison kills circulated on the internet, Park officials met with representatives of American Indian tribes, the state of Montana and other federal agencies. Afterwards, the group has announced that culling efforts will not begin until February 2016, and that there will not be a specific target number. Some tribal governments are still calling for trapping to be delayed until late March.

Since the 1980s, more than 6,300 wild bison have been slaughtered and almost 1,900 killed by hunters. Yet the Yellowstone bison herds have grown to near-record levels - approximately 4,900 animals in 2015. Last winter, officials had the goal of removing 900, but only achieved this for 737 animals. This year the plan is to kill mostly calves and females to affect both the numbers and the reproductive rate.

Yellowstone Park is well aware of the public's disapproving attitude towards slaughtering and hunting wild bison, but its hands are tied. The cull is a continuation of the controversial agreement with Montana.

"Through the legal agreement the National Park Service has to do this," said Yellowstone spokeswoman Sandy Snell-Dobert. "If there was more tolerance north of the park in Montana for wildlife, particularly bison as well as other wildlife, to travel outside the park boundaries, it wouldn't be an issue."

If 1,000 bison were removed, about 300-400 would be hunted by Native Americans outside of the park (Congress has specifically prohibited hunting within Yellowstone). As many as possible would be used in research facilities but the demand is nominal. The balance would be shipped to meat processing facilities.

Some people question why the northern border of Yellowstone can't be fenced to prevent the bison from crossing over to Montana. The NPS FAQ page responds, "Annual migration allows bison to access necessary resources for their survival—similar to bighorn sheep, deer, elk, moose, and pronghorn in the system. If migration by Yellowstone bison into Montana is restricted or shortened by human intervention, then bison numbers will be largely determined by food availability inside Yellowstone, with substantial winter mortality occurring after bison reach high densities.

"Fortified fences could be used to limit bison migrations, but they would also impede or serve as a barrier to the movements of other wildlife species such as bighorn sheep, deer, elk, moose, and pronghorn. Fencing creates a zoo-like atmosphere and is generally inconsistent with wildlife management principles for the State of Montana and the NPS.

"The distribution of hay or commercially prepared rations at locations near the boundary of Yellowstone National Park during winter could conceivably encourage bison to terminate their migration and remain in the park. However, bison and other ungulates would become increasingly reliant on these provisions while continuing to feed on vegetation in the vicinity and degrading surrounding habitats. These outcomes are contrary to the conservation of a wild bison population and NPS policies for managing biological resources. Most natural resource managers attempt to avoid the supplemental feeding of wildlife."

Bison walking through deep snow near Tower Junction in March. Photo by NPS Jim Peaco.

Bison walking through deep snow near Tower Junction in March. Photo by NPS Jim Peaco.

February, 2014: This February, 20 wild bison from Yellowstone have been transferred to a Montana Native American tribe for harvesting. Another five were transferred to the U.S. Department of Agriculture for use in a contraception program. This is in accordance with a multiyear plan to reduce the herd from about 4,600 to 3,000. Up to 600 bison could be killed this winter.

The last time a major reduction of herd was implemented was in 2008, when 1,600 were killed.

The video below, "Silencing the Thunder," shows many sides of the story.

Silencing the Thunder from Forest Clay Productions on Vimeo.

Shorter version of "Silencing the Thunder" on YouTube

January, 2013: Biologists in Yellowstone National Park recommend that 450 bison be killed this winter in order to “reduce abundance and growth potential,” reported Wyoming’s Star Tribune.

Estimates from 2012 report that Yellowstone has roughly 4,200 bison. These animals are divided into two herds: the central herd that stays primarily near Old Faithful and the Firehole and Madison river drainages, and the northern herd that gathers near the Lamar Valley and Yellowstone River drainage. Currently, the central herd has about 1,600 animals, while the northern herd has 2,600 animals, the most it’s ever had, according to park officials.

Ideally, the park service would like to see each herd have roughly 1,500 bison, with an equal number of males and females.

“Hunting and management removals of approximately 400 bison per year would provide a high certainty of approaching all desired conditions within five years,” reads the Interagency Bison Management Plan statement.

Without thinning the herds this winter, biologists say that there’s a 50 percent chance of bison numbers rising to more than 4,875 entering into the 2014 winter.

Those against the culling strategy argue that bison should be allowed in a larger area, rather than slaughtering the animals. Dan Brister, executive director of the Buffalo Field Campaign, a conservation group, supports enlarging the bisons’ habitat.

“We’d like to see them treat bison more like elk are treated,” he told the Tribune. “There’s a lot of great habitat they’re being excluded from.”

December 22, 2011: Montana Governor Brian Schweitzer is arguing with the U.S. Federal government over what to do with the upcoming winter’s overflow of hungry–and potentially brucellosis* exposed–Yellowstone National Park bison. TheAssociated Press reported that Interior Secretary Ken Salazar is proposing to move the bison to South Dakota’s Pine Ridge Indian Reservation and Great Sand Dunes National Park in Colorado. Gov. Schweitzer is adamant that the bison belong to the state of Montana and stay in Montana; he proposes moving them to the National Bison Range in the western part of the state and is blocking all shipments of fish and wildlife out of the state. The Department of the Interior believes transferring the bison to the National Bison Range will “stigmatize” the existing herd, although all bison slated for transfer have been found to be free of brucellosis. An alternate to transferring the bison is slaughtering them as has happened in years past. The projected number of bison expected to leave the park in search of food this winter is 1,000. Read the full AP article.

January, 2011: Limited food supplies within Yellowstone National Park in winter months leave hungry bison with little choice but to migrate to lower elevations not blanketed in snow. While park officials have made serious efforts to keep the animals from leaving the park, they have had little success. This year the roaming bison are being herded to holding pens at the Stephens Creek facility inside Yellowstone and, for the first time, the Brogan Bison facility at Corwin Springs. In total over 500 bison are currently being held at the two facilities.

Much of the controversy surrounding the wandering Yellowstone bison boils down to a disease some, not all, of the animals carry–*brucellosis, a bacterial infection that can cause cattle to miscarry, and is transferable between several species of animal. Ranchers have good reason to keep their cattle away from bison and other infected animals (elk can also carry the disease)–once a population becomes infected the cost to ranchers becomes immense (due to testing and slaughter expenses) and Montana ranchers are intent on maintaining their brucellosis-free standing.

In the past, as the Yellowstone holding pens reached capacity officials have been left with little choice but to send some bison to slaughter, a move that angered many, including Montana Governor Brian Schweitzer. Schweitzer recently passed a 90-day halt on the slaughter of Yellowstone bison. The bill allows for enough time to herd bison back into the park come May 15, after the so-called “green-up” when the snow is melted and grass sprouts.

Currently incoming bison are sorted into infected and non-infected pens at the Stephens Creek facility. Some of the disease-free bison are then transferred to the Brogan facility; come spring the healthy bison will be returned to the park. A decision has not been made about the fate of the infected bison following the 90-day reprieve.

The holding pens, while an improvement over mass slaughter, are not a long-term solution for corralling hungry, wild bison. Montana lawmakers and the federal government have been working on a solution for years although previous agreements have yet to come to fruition.



Yellowstone Bison Hunt Takes Record Numbers

So far in 2013 hunters have killed more wild bison migrating from Yellowstone National Park than any year since 1989. Participation by American Indians, who harvest the animals under long-standing treaty rights, helped to drive the numbers skyward.

Bison walking through deep snow near Tower Junction in March. Photo by NPS Jim Peaco.

Yellowstone Bison Win a Court Case

March, 2014: The Montana Supreme Court has ruled that bison can temporarily roam outside the Yellowstone Park boundaries during winter without being killed.