Office of External Affairs
Mountain-Prairie Region


U.S. Fish and Wildlife Service
Mountain-Prairie Region
134 Union Boulevard
Lakewood, Colorado 80228

February 23, 2011                                                                             Contacts: Joy Gober 970-226-9195





The U.S. Fish and Wildlife Service has concluded that a petition to list the wild plains bison under the Endangered Species Act (ESA) does not contain substantial scientific data to indicate that the petitioned action might be warranted.  Despite this announcement that the bison will not receive further consideration for listing under the ESA at this time, the Service will continue to work with our partners to conserve and protect wild plains bison throughout its remaining range.


The Service made this determination in response to a petition received on June 22, 2009 from James and Natalie Bailey to list the wild plains bison as a threatened species.  Under the ESA, the Service is required to review the petition to decide whether it contained substantial scientific information that listing may be warranted in a process known as a 90-day finding.


Bison are the largest native terrestrial mammal in North America.  Historically, plains bison numbered in the tens of millions and were found nearly coast to coast from central Canada to northern Mexico. They were eliminated west of the Rocky Mountains and east of the Mississippi River by the early 1800s.  By 1889, only a few wild plains bison remained in the Texas Panhandle, Colorado, Wyoming, Montana, and the western Dakotas, as well as a small number in captive herds.  Diligent efforts by a few individuals prevented extinction.  Conservation efforts by private landowners, state and federal agencies, and others helped to rebuild herds.  Today, there are over 400,000 plains bison, with approximately 20,500 managed in conservation herds in parks, preserves, other public lands, and on private lands throughout and external to their historical range.  Population trends have been stable to increasing in recent years.


The Service assessed information provided by the petitioners and in our files regarding potential impacts to the plains bison from habitat loss, disease, regulatory mechanisms, loss of genetic diversity, introgression with cattle genes, and climate change. We determined that the petitioner did not present substantial information that these factors threaten the wild plains bison today. Although the bison quite clearly faced a large historical decline in numbers and occupied habitat, the petitioner did not present substantial information, nor did we have any information in our files, to indicate the threats that caused the historic decline may be present now or are likely to be present in the future to the point that they would cause the wild plains bison to become threatened or endangered. 


The Service will continue our cooperative efforts to conserve the existing bison herds in the United States.  We will continue to cooperatively implement the Joint Bison Management Plan and the Department of Interior’s Bison Conservation Initiative.  The Joint Bison Management Plan is a comprehensive approach to protecting plains bison in Yellowstone National Park and minimizing the transmission of brucellosis to neighboring cattle.  The Bison Conservation Initiative provides a framework for managing bison within the Department of Interior that includes restoring bison on appropriate landscapes, maximizing genetic diversity, and controlling contagious disease.  Bison conservation will also continue to be a priority of the National Wildlife Refuge System and the National Park System, which currently protect plains bison on eight National Wildlife Refuges and five National Parks.


In addition to federal cooperative efforts to conserve existing herds and establish new herds, several state governments and private entities participate in restoration of the plains bison.  State managed conservation herds exist within the species’ historical range in Arizona, Kansas, Minnesota, Missouri, Nebraska, South Dakota, Texas, Utah, Wisconsin, and Wyoming.  Additional state herds external to its historical range exist in Alaska.  The Nature Conservancy manages eight herds for conservation purposes, with initiatives for establishing two new herds.  Turner Enterprises manages several herds with dual purposes of conservation and commercial production.  The American Prairie Foundation and the World Wildlife Fund have also developed conservation herds.


A copy of the plains bison finding is available on the Internet at


The finding will be published in the Federal Register on February 23, 2011.


The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people.  We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service.  For more information on our work and the people who make it happen, visit