Management
Who manages Yellowstone bison?
The Interagency Bison Management Plan (IBMP) guides the management of bison in and around Yellowstone National Park. Five federal/state agencies and three tribal entities implement the plan.
Why are bison killed every winter?
- Bison are killed because there are too many animals in too small a space. Yellowstone encompasses a limited amount of habitat and Montana only allows very limited numbers of bison in small areas adjacent to the park.
- Allowing the bison population to grow indefinitely will cause overgrazing and possibly mass starvation of animals in Yellowstone, as well as larger migrations and greater conflict outside the park.
- We don’t know of any bison conservation herds in North America that are naturally regulated: all require population reduction by capture and removal or hunting.
- Yellowstone bison currently reproduce and survive at relatively high rates compared to many other large, wild, mammal species. The bison population increases by 10 to 17% every year (that’s ten times faster than the human population grows worldwide).
- Currently, predation by bears and wolves has little effect on the bison population. Bison are massive animals that defend themselves as a group, making them more difficult to attack than animals such as elk.
- Hunting outside the park has not been effective at limiting bison numbers because concentrated hunting pressure along the park boundary often causes bison to return to the security of the national park where hunting is prohibited.
How many bison will be killed this winter?
The operations plan for winter 2017/2018 has not be finalized. For the winter of 2016/2017, IBMP members collectively decided to reduce the bison population. In order to accomplish this, 900 to 1300 animals must be removed through hunting outside the park and capture/shipment to slaughter at the Stephens Creek facility.
Aren’t bison protected as our national mammal?
No: that designation did not provide any special protection to bison. Read more about the National Bison Legacy Act.
Why do bison leave the park?
Bison migrate to lower elevations in search of food during winter, just like bighorn sheep, elk, mule deer, pronghorn, and many other animals. They return to the park’s higher elevation grasslands to feed during summer.
Why do states treat bison differently than other wildlife when they leave the park?
Bison are not allowed to move freely outside Yellowstone due to fears they might transmit brucellosis to cattle (see below for more info), and out of concerns about competition with cattle for grass,human safety, and property damage. Elk are also infected with brucellosis, but their movements outside the park are not restricted. State governments control the management of wildlife outside Yellowstone (unless a species is federally listed as threatened or endangered).
Why don't you force surrounding states to change their policies?
Outside Yellowstone, states manage wildlife and Yellowstone cannot force them to tolerate more migrating bison.
Why don’t you just ignore the IBMP and let the bison go?
Doing nothing is not a realistic option. Allowing the bison population to grow indefinitely will cause overgrazing and possibly mass starvation of animals in Yellowstone, as well as larger migrations and greater conflict outside the park.
How are bison captured?
On behalf of the IBMP, bison are captured near the north boundary of Yellowstone as they migrate out of the park. Fences guide them into enclosures, so they wander in on their own or are sometimes pushed in by riders on horseback. For more information on the capture and shipment process, take a video tour of the Stephens Creek facility or browse photos in our Stephens Creek album on Flickr.
How are bison killed?
We transfer captured bison to our tribal partners who have them shipped to slaughterhouses.
What happens to the meat?
Our tribal partners distribute the bison meat and hides to their members.
Does Yellowstone profit from shipments of bison?
No: we receive no payment for bison shipped from our capture facility.
Are animals abused at Stephens Creek?
No. The safety of people and animals is our top priority at Stephens Creek. The Humane Society has evaluated the operation twice, and each time we've adopted their recommendations. These have included creating visual barriers (plywood walls) so the animals can’t see out of the corrals, and eliminating all nonessential people from the catwalks during processing. Two old photos are often used to falsely depict our handling practices at Stephens Creek. One shows a bison being held with a nose ring during brucellosis testing, a practice we haven’t used in many years (we now have a hydraulic chute that holds the animals relatively still during testing). The second shows a bison being carried by a front-end loader: a photo that was taken outside the park, most likely after a bison was shot by a hunter or hit by a car. Adult bison can be very large and heavy and often times require heavy equipment to move carcasses from vehicle accident scenes. For a detailed view of the capture and shipment process, take a video tour of the Stephens Creek facility or browse photos in our Stephens Creek album on Flickr.
Does culling put the population at risk?
No. Yellowstone’s bison population has grown steadily over the last 45 years: from 500 animals in 1970 to 5,500 in 2016. Along with elk, bison are the most numerous large mammals in Yellowstone, and periodic culling will not alter that fact. The sizes of most wild ungulate populations in North America are limited by hunting and/or captures and removals.
Are you catering to the livestock industry?
We are legally obligated to follow the directives of the the IBMP. Each member of the IBMP has a different perspective on the conservation of wild bison, so conflict resolution is an integral part of the management strategy. We would like to reduce the need for capture and shipment to slaughter, but that would require changing the current bison management plan and agreement from all members of the IBMP.
