Help list Yellowstone Bison as an Endangered Species

Yellowstone bison need Endangered Species Act protection due to destruction of habitat and migration corridors, government slaughter and intolerance, domestication and livestock management, and rapid climate change.

Yellowstone Bison Endangered Species Status Review is Open for Public Comment

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The U.S. Fish & Wildlife Service announced the scientific review on June 5, 2022, after years of advocacy and two court decisions compelling the agency to recognize evidence in our Endangered Species Act petition that the migratory bison herds in Yellowstone may be at risk of extinction.

Buffalo Field Campaign and Western Watersheds Project filed our petition in 2014. Our attorneys from Friends of Animals successfully defended our petition in court.

The endangered species status review is a rule making process – open to public comment for a period of 12 months – to determine if our petitioned action is not warranted, warranted but precluded, or warranted.

The U.S. Fish & Wildlife Service’s decision for Yellowstone bison must be based “solely upon the best scientific and commercial data available.”

Your comments in support for protecting and recovering Yellowstone bison in the wild are vitally important. The window of opportunity for sending comments is open through June 4, 2023.

To comment, go to

Endangered Species Act protection would ensure our natural heritage of wild bison in Yellowstone is secured for generations to come. You, the people, can be the deciding factor in protecting and recovering our beloved bison in the one place where they still roam wild: the Yellowstone ecosystem.

Please take action today by sending in your comments in support of protecting and recovering wild Yellowstone bison.

Need help developing a unique comment? Click on our FAQ to help you get started.

Frequently Asked Questions

How can I submit a comment?

    To comment, go to Click on the Comment tab. Type in your unique comment. You can also attach electronic files. Select an identifier (individual, organization, or anonymous). Scroll down and click on Submit Comment.


    What factors threaten or endanger wild bison in Yellowstone?

      There are many factors threatening Yellowstone bison in the wild, a few are listed here:

      • Loss of habitat and home range to cattle.
      • Loss of long distance migration corridors to human developments.
      • Loss of connectivity to habitat impairing bison’s ability to migrate in response to natural or human-made disturbances.
      • Exclusionary management boundaries preventing bison’s natural migrations on public lands.
      • The State of Montana’s intolerance for wild bison in the state.
      • Yellowstone National Park’s trapping bison for slaughter operations - ongoing since 1996 and the single largest source of mortality.
      • The U.S. Forest Service’s land management plan excluding bison from substantial portions of the migratory species’ National Forest range and habitat.
      • Management actions leading to the domestication of the wild species such as trapping, quarantining, vaccinating, birth control experiments, etc.
      • Management actions impairing bison’s ability to naturally adapt and evolve in the Yellowstone ecosystem.
      • Montana Dept. of Livestock authority over wild bison migrating into the state (MCA § 81-2-120).
      • The lack of State and federal measures for conserving Yellowstone bison in the wild.
      • Rapidly rising temperatures threaten bison’s ability to adapt to increased heat stress.
      • Less nutritious grasses resulting from climate change.

      Any factor threatening or endangering Yellowstone bison is cause for protecting and recovering wild bison under the Endangered Species Act.

      What is a threats assessment?

        It is an assessment of Yellowstone bison’s “ability to maintain self-sustaining populations over time . . . based on the best available scientific and commercial information regarding the life history, biology and consideration of current and future vulnerabilities.” For more information, visit U.S. Fish & Wildlife Service’s Species Status Assessments web page.

        It is also a framework by which the U.S. Fish & Wildlife Service evaluates the status of Yellowstone bison using the biological principles of representation, resiliency, and redundancy.


        What are the three Rs?

          Shaffer and Stein broadly define the biological principles of representation, resiliency, and redundancy as “saving some of everything,” and “saving enough to last.”

          In their application to Yellowstone bison:

          Representation is saving populations “in an array of different environments,” and “the ecological and evolutionary patterns and processes” that allow for natural selection, adaptation and reproduction in the wild.

          Redundancy is the ability to withstand catastrophic events by “having essential backups” elsewhere “as a hedge against the failure of any individual population” in the wild.

          Resiliency is the ability to withstand disturbances and adverse events in protected habitats large enough to accommodate population dispersal and recovery in the wild.

          Mark L. Shaffer & Bruce A. Stein, Safeguarding our Precious Heritage, (2000).

          “Together, the 3Rs, and their core autecological parameters of abundance, distribution and diversity comprise the key characteristics that contribute to a species’ ability to sustain populations in the wild over time. When combined across populations, they measure the health of the species as a whole.” U.S. Fish & Wildlife Service Guidance on Responding to Petitions and Conducting Status Reviews under the Endangered Species Act (August, 2016, PDF).

          What criteria are used in considering whether wild Yellowstone bison are threatened or endangered?

            Any of the following factors (individually or in combination) determine whether a species is threatened or endangered under the Endangered Species Act:

            • The present or threatened destruction, modification, or curtailment of its habitat or range.
            • Overutilization for commercial, recreational, scientific, or educational purposes.
            • Disease or predation.
            • The inadequacy of existing regulatory mechanisms.
            • Other natural or manmade factors affecting its continued existence.


            Is asking a question a comment?

              Yes. For example, what evidence exists that Yellowstone bison in the wild can adapt to rapidly rising temperatures and climate change over the next century?

              Your questions should focus the U.S. Fish & Wildlife Service’s attention on any factor threatening or endangering Yellowstone bison in the wild. For example, what State or federal regulatory mechanisms exist to perpetuate self-sustaining herds of Yellowstone bison in the wild?

              It is the “declared national policy of saving endangered species,” to “halt and reverse the trend toward species extinction, whatever the cost.” Tennessee Valley Authority v. Hill, 437 U.S. 153 (1978).

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              Endangered Species Ads

              Share and post our Endangered Species ads for American bison
              Buffalo Field Campaign Help Save The Yellowstone Bison ad 1 (PDF)
              Buffalo Field Campaign Help Save The Yellowstone Bison ad 2 (PDF)
              Buffalo Field Campaign Help Save The Yellowstone Bison ad 3 (PDF)


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              (Download a PDF version)

              Legal actions to list the Distinct Population Segment of Yellowstone bison as threatened or endangered

              Court Case

              U.S. District Court Judge Randolph D. Moss's decision, Buffalo Field Campaign, Western Watersheds Project, Friends of Animals v. Martha Williams, Jan. 12, 2022 (PDF, bench opinion)

              Buffalo Field Campaign v. Williams, 2022 WL 111246 (slip copy) (PDF, Word)

              Buffalo Field Campaign v. Zinke, 289 F. Supp. 3d 103 (D.D.C. 2018) (PDF, Word, published case)

              U.S. District Court Judge Christopher R. Cooper’s decision, Buffalo Field Campaign v. Zinke, Jan. 31, 2018 (PDF, bench opinion)


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              Click here to see the full endangered species ad (PDF).
              Click here to view the endangered species ad resources (PDF)


              January 13, 2022
              Yellowstone bison get another shot at ESA listing after federal judge agrees with wildlife protection groups 

              March 24, 2020
              Groups Seek Protection for Yellowstone Bison Amid Roundup and Slaughter

              September 6, 2019
              Conservationists blast USFWS Denial of Yellowstone Bison Protection

              February 1, 2018
              Court Overturns Political Decision to deny Endangered Species Protection to Bison



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              Click here to see the full endangered species ad (PDF).
              Click here to view the endangered species ad resources (PDF)

              Petitions to list the Distinct Population Segment of Yellowstone bison

              Buffalo Field Campaign & Western Watersheds Project, Petition to list the Yellowstone Bison as a Distinct Population Segment under the Endangered Species Act, Nov. 13, 2014 (PDF).

              James Horsley, Petition to List the Yellowstone National Park Bison Herd as Endangered (Jan. 5, 1999) (PDF 2.9MB)

              James Horsley, A Petition to Protect Yellowstone's Wild Bison from Extinction (Jan. 2017) (PDF 13MB)

              James Horsley, Yellowstone's Wild Bison On the Brink of Extinction (Feb. 2018) (PDF 6.5 MB)


              A Short Film by Sharon Colman

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              (A non-affiliated project and artwork to give the wild American bison a voice).