At least 100 Yellowstone National Park bison have been trapped in corrals near the town of Gardiner since Saturday as the National Park Service begins its grim winter work of shipping some of the wild animals to slaughter

One large cohort of bison annually migrates north from the park in winter in search of forage as deep snow covers the interior. Another band migrates along the Madison River on the west side of the park exiting near West Yellowstone.

“We’ve been seeing them migrate through the month of December,” said Morgan Warthin, park spokeswoman. “We had anticipated this given the predictions of wintry weather. On the plateau there’s been a lot of snow and cold.”

Animals trapped by the Park Service are shipped to slaughter facilities for processing with the meat distributed to designated tribes.

Hunt zone

When the animals cross the park boundary into Montana near either entrance they become fair game for licensed state hunters as well as tribal members with treaty hunting rights. So far this winter, tribal hunters have reported taking 80 bison, 36 from the west side and 44 from the north, while state hunters have harvested 19 bison, only six of which came from the north side, according to the Montana Department of Fish, Wildlife and Parks.

Last year the Park Service delayed its bison trapping until Feb. 15 to see if tribal hunters would be more successful. As a result, hunters killed 384 bison, rangers killed 18 wounded animals and 101 were sent to slaughter, short of the park’s original goal of removing 600 to 900 animals through hunting and trapping. 

“There’s a balance between hunting and population management,” said Sam Sheppard, FWP’s Region 3 supervisor in Bozeman. “We fully support operation of the trap. They’ve always done a good job of allowing enough bison to pass by … for tribal and state hunters.”

Warthin said park staff wait until bison have moved back from the state boundary — often after being pressured by hunters — before herding them into the Stephens Creek Bison Capture Facility’s corrals.

Winter removal

The Park Service, in concert with cooperating agencies, is aiming to reduce the northern herd that migrates to the Gardiner Basin by 900 to 1,400 animals this winter. The northern herd is estimated at about 4,000 animals. The entire park’s bison population is close to 5,500, an 11 percent increase from 2015.

That rate of increase is much higher though — 24 percent — after adjusting for bison that were removed from the population through culling and harvest, according to the park’s own analysis.

“This increase was substantially higher than the 15-year average of 14 percent and suggests that the bison population is undergoing exponential growth — characteristic of a population that has not reached carrying capacity,” according to an annual report by park biologists. “This increase also suggests that the Park Service underestimated the number of bison in the population last year.”

Yellowstone National Park’s growing bison population has become a point of contention between the National Park Service and the state of Montana, which borders the park to the north and west. Because the bison migrate out of the park and carry a disease that can cause pregnant cattle to abort, Montana has pushed the Park Service to reduce Yellowstone’s total bison population to less than 3,500. Yellowstone officials have calculated that a herd of 3,000 to 5,000 is necessary for the animals to maintain genetic diversity.

Controversy

This year’s bison reduction efforts come on the heels of the animal being designated a national mammal of the United States because it is a historical symbol of the U.S. and was once “integrally linked with the economic and spiritual lives of many Indian tribes through trade and sacred ceremonies,” according to the text of the National Bison Legacy Act

Also in 2016, three groups filed a lawsuit in U.S. District Court in the District of Columbia seeking to order U.S. wildlife officials to re-examine whether the Yellowstone bison should be listed as a threatened or endangered species. The Yellowstone herd is one of the last free-roaming wild herds that is genetically pure. Many of the bison raised on cattle ranches have been interbred with cattle. 

One of the groups named in the lawsuit, Buffalo Field Campaign, again denounced the park’s capture for slaughter program in an email this week.

“… Here we have the supposed care-takers of the country’s last wild, migratory herds shipping them to slaughter to cater to the whims of producers of an invasive species — the domestic cow,” said Stephanie Seay, of the Buffalo Field Campaign.

Seay is referring to the fact that there has been no documented case of Yellowstone bison transmitting brucellosis to cattle, although the majority of the park’s bison have been exposed to the disease. Although some cattle outside of the park have tested positive for exposure to brucellosis — which results in constrictive and expensive quarantines — the transmissions have been traced to wild elk, which also carry the disease.

“Montana’s livestock lobby continues to play deadly political games with this keystone species, which is not in the least guilty of the crimes cattlemen blame them with,” Seay said. “In truth, invasive cattle have left death, pollution and destruction in their wake across the lands of the West, and only wild, migratory buffalo can heal these injuries. Only wild buffalo can restore the grasslands and prairie communities, which are some of the most threatened habitats in the world.”

The Montana cattle industry, which works with state and federal agencies to direct bison management in the state, sees the issue much differently.

“Even the Park Service recognizes their northern herd is over population objective,” said Jay Bodner, natural resource director of the Montana Stockgrowers Association. “They recognize they need to be managed for a declining population.”

Expanding the so-called tolerance zone for bison to wander outside the park, as other wild animals are able to do, is not an option without population control, Bodner added.

One option to remove bison without slaughtering them is to ship them to other facilities where they are valued for their unique genetics. But that requires that the animals are disease free. Last year 49 animals that tested negative for exposure to brucellosis were quarantined at the Stephens Creek facility. They are still being held in the corrals. The capture facility is typically operated through March, although the success of roundups is based on the number of animals in the area. Once spring arrives and the snow melts, bison migrate back into the park.

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