Mar 11

Finding a Future for Yellowstone’s Bison

No Room to Roam: Finding a Future for Yellowstone’s Bison

By: Jenny Golding

This article was first published in the Winter 2017 issue of Yellowstone Quarterly.

Standing on a grassy hillside above Lamar Valley in early august, you watch as a sea of black dots shifts and morphs across the golden landscape. Bison! The air smells of sage and crackles with dryness. Bison are gathered by the thousands in Hayden and Lamar valleys for their mating season—the rut. Hulking bulls, weighing 2,000 pounds or more, thunder their way across the valley floor, bellowing furiously at one another as they compete for receptive females. Towering clouds of dust rise from the ground as the bulls wallow and strut. What you see before you is unique in the world: a wild population of bison roaming freely across the 2.2 million acres of Yellowstone National Park. “This is the last genetically pure population that lives as their ancestors did: unfenced, unprotected from harsh winters, drought, or predators,” says Yellowstone National Park Chief of Strategic Communications Jody Lyle.

A Long Journey Home

Standing on the same hillside in Lamar Valley in 1900, you would have seen…nothing. Approximately 30-60 million bison once roamed the continent from the Appalachians to the Pacific. Traveling a 2-3 million-year journey from Southeast Asia across the Bering Land Bridge to North America, bison outlasted mammoths, mastodons, dire wolves, and other Pleistocene-era peers. But by 1901, only about 23 wild bison remained in the Yellowstone area, taking refuge in the Pelican Valley in Yellowstone National Park. It’s a staggering statistic, as if all the people from the 50 largest cities in America today simply vanished.

Only bison didn’t vanish—they were exterminated. Casualties of westward expansion, millions of bison were slaughtered over a period of just 200 years. In 1872—the year Yellowstone National Park was established—the slaughter averaged 5,000 animals a day, every day.

To save them from extinction, the U.S. Army relocated 18 pregnant cow bison from the Pablo-Allard herd in northwestern Montana and three bulls from the Goodnight herd in Texas to Yellowstone in 1902. Through husbandry and protection, the population grew to 1,500 animals by 1954. Today, about 4,900 bison roam wild and free in Yellowstone—a triumph of conservation.

That success has not been without controversy.

Conflicting Wildlife Values

Fast forward seven months from the rut, to March. Winter for bison is bleak; snow blankets the landscape, making forage scarce. As the snow deepens, bison follow an ancient instinct: migrate to winter range where food is more readily available. For most of the 20th century, until the 1980s, bison didn’t seasonally migrate out of the park due to relatively low numbers and management actions. Today, however, some bison are migrating out of Yellowstone—and into the crosshairs of a heated debate about their right to roam.

Once they leave the park, bison enter a world that no longer has room for them. The broad valleys that once provided refuge during colder months are now a patchwork of houses, fences, grazing allotments, and cattle ranches. Bison are migratory wildlife, which brings them into conflict with people living in these areas.

On the surface, it appears this conflict stems from concerns over a bacterial disease called brucellosis, which wild bison and elk contracted from domestic cattle brought to the surrounding area in the late 1800s and into the park in the early 1900s. About 60 percent of the park’s bison have been exposed to the organism, although only about 15 percent of females are infectious. Transmitted between bison, elk, and cattle through infected birth tissue, brucellosis can cause these animals to abort their calves.

The period of significant transmission risk occurs during the late winter and spring, when elk and bison are calving. Although the risk of transmission from elk to cattle is greater than from bison—elk roam freely during this time whereas bison do not—concern that cattle will contract brucellosis from wild bison still raises serious fears in those who raise livestock for a living.

“When an animal in a livestock herd is infected, that herd is immediately quarantined; the owner can’t sell anything except to slaughter, even if pregnant. The quarantine lasts until all animals are removed…or animal health officials are sure that the disease is no longer in the herd. That can have a significant impact on those ranching families,” says Montana state veterinarian Marty Zaluski.

Fears that bison might transmit brucellosis back to cattle, as well as concerns for human safety, property damage, and competition with cattle for grass, resulted in Montana legislation prohibiting the movement of wild bison beyond the park and a few adjacent areas, except to slaughter. This conflicts with the park’s mission to preserve wildlife and the ecological processes (such as migration, grassland interactions, and predator-prey dynamics) they sustain.

It took a court-mediated settlement agreement in 2000, known as the Interagency Bison Management Plan (IBMP), to help sort out differences in management approach. Today, eight federal, state, and tribal partners work together to minimize the risk of brucellosis transmission to cattle, lower brucellosis prevalence, and prevent dispersal beyond the designated conservation area, while supporting a wild, free-ranging population that maintains its genetic integrity and ecological functions. If these actions sound conflicting, they often are. “What we do on the boundary is not about bison ecology,” says Yellowstone National Park biologist Rick Wallen. “It’s strictly conflict resolution.”

It’s difficult to make sense of this complicated socio-political story on a good day. Watching how the IBMP plays out on the ground in winter can be heartbreaking.

As bison herds flow out of the mountains above Mammoth Hot Springs to the Gardiner Basin, they have 6 miles of winter range before they encounter the park border. While there is some tolerance for bison beyond the border, their path is filled with obstacles. Some are met by tribal and public hunters. Others meander into fences that funnel them into the Stephens Creek bison handling facility, where they are corralled and shipped to slaughter-their meat given to Native American tribes. Those that make it through can roam only as far as Yankee Jim Canyon, 6 miles from the park border, where a cattle guard, tall fences, cliffs, and the Yellowstone River pen them in.

At the Stephens Creek facility, National Park Service (NPS) workers place a metal catwalk above a narrow chute lined with plywood, as 20-30 bison are herded into the passageway. One at a time the bison are released into the “squeeze chute,” a giant hydraulic metal basket that lifts and squeezes the animal to hold it still. The biologists quickly collect a blood sample and record the weight, a process that takes under 2 minutes. Afterwards, small groups of animals are ushered into the back of livestock trailers, hooves thundering on metal as they barrel into the trucks. In sharp contrast to the image of the powerful bull strutting Lamar Valley in August is a brief glimpse of a wild eye peering out through the metal slats in the side of the trailer-confused, defiant, afraid. The doors are locked and off they go, accompanied by armed guards. It’s hard to watch. There’s not much to say.

The objective to kill wild bison was a request by the state of Montana to limit the number of bison that leave Yellowstone National Park. The settlement agreement established a target abundance of 3,000 bison and established management areas adjacent to the park boundary where removal actions would occur. Over 1,200 bison were removed from the population in 2017, primarily through hunter harvest and slaughter. More than 8,000 bison have been culled since 1985.

A common misconception is that park staff are comfortable with their role in this intensive management of the Yellowstone bison herd. NPS operates this facility on behalf of the IBMP partnership, doing their best under challenging circumstances. “All of the operations here are structured around how to reduce stress for the bison,” says park spokesperson Morgan Warthin. From the custom-designed squeeze chute and the plywood on the walls, to the way bison are loaded in the trailers, “the goal is to make the operation as efficient as possible and to reduce injury and stress.” Still, it’s hard to witness.

The state and tribal hunt can be equally wrenching. While hunting is one of the management tools set forth in the IBMP for controlling the bison population, the hunt as it happens today is less than ideal. Because hunting is not allowed in the park (as some have proposed), and year-round tolerance for bison outside the park has been very limited in the past, the animals are harvested only in winter when they migrate out. It’s the time when bison are in the poorest condition, and cows are in late pregnancy. Hunters congregate close to the park border, sometimes killing bison in large groups. As ravens and eagles circle eagerly over the remains, it can be hard to understand how this is part of a positive future.

Although the way the hunt happens now needs improvement, says Tom McDonald with the Confederated Salish and Kootenai Tribes (CSKT), the tribes are committed to participating in the process of bison conservation. They envision a future where bison roam all federal lands in Montana. It’s a big dream, and working towards a successful tribal treaty hunt is an important part of demonstrating that bison can be managed on public lands. “Rounding up wild bison and putting them in cargo trailers and hauling them hundreds of miles and putting them in the slaughterhouse is not an ideal situation by anyone’s standards,” says McDonald. “They have to be…taken in the field, given the respect they should have.”

Hope for the Future

Despite these challenges, the park remains focused on moving forward. “Doing nothing is not an option,” says Jody Lyle. “Our goals are clear. We want to maintain the healthy population in the park; we want to reduce the number of animals that we have to send to slaughter each year; and we want to populate new conservation herds around the West with Yellowstone bison.”

The park has proposed sending Yellowstone bison to a quarantine facility specifically built for the purpose on the Fort Peck Reservation, in collaboration with the Assiniboine and Sioux tribes. From quarantine, animals that repeatedly test negative for brucellosis could be sent
to other public, private, or tribal lands. This approach would reduce the number of animals sent to slaughter, and foster other populations of Yellowstone bison across the country.

Yet it’s impossible to move forward without something changing at the state level, and Montana’s stance is firm: transporting animals-in a locked trailer-that have not completed the quarantine process is too big a risk to livestock producers. “The country hasbeen engaged in a brucellosis eradication campaign…since the 1930s,” says veterinarian Zaluski. “We have concerns that sending animals to quarantine out of an area where we have brucellosis to an area where we don’t…is contrary to the spirit of the…campaign,” adding that Montana state law prohibits this movement. It’s a literal roadblock.

The park disagrees about the level of risk. Biologists have learned a lot about bison ecology and disease transmission in the years since the 2000 IBMP, and recent public opinion polls show that 76 percent of Montana voters support restoring wild bison to public lands. While the existing plan has been successful in preventing the transmission of brucellosis from bison to cattle, the park believes that it’s time to write a new plan that reflects recent science and public opinion, and which recognizes bison as wildlife. The beginning stages of a new IBMP are underway.

Following the trauma of winter, it can be hard to see a positive story here. Yet with the emergence of green grass in the spring and the birth of little red bison calves comes a new hope for the future. “It may seem slow, but we have accomplished a lot,” says Lyle. “If anything, the conservation success over the past century is so amazing that now…we are having conflicts outside our borders as they migrate out. That didn’t happen for the past 100 years because there weren’t enough bison to do it.”

Bison are a public resource; they belong to all Americans. Until politics catch up with science and public opinion, there are few options to control a population that could outgrow available habitat. Finding a home for Yellowstone bison in the future is ultimately about tolerance and working together. “We’re trying to find solutions other than capture and ship to slaughter,” says Yellowstone Superintendent Dan Wenk. “We’re working with our partners to find what those solutions can be.” It’s not an easy task. Zaluski elaborates: “If there was an easy way to solve this problem, we would have done it already.”

Note: Author Jenny Golding interviewed Jody Lyle, Tom McDonald, Rick Wallen, Morgan Warthin, Dan Wenk, and Marty Zaluksi for this article in the fall of 2017.

Jenny Golding is a former director of education for Yellowstone Forever. She currently runs the website A Yellowstone Life, and writes from her home in Gardiner, Montana, on the border of Yellowstone National Park.

To learn more: Visit the bison fact page on our website at View photos, listen to an informative podcast, and read more about management in Yellowstone National Park. Comprehensive bison management information is also available at