On Tuesday, April 06, 2004, 198 bison that were being held at the Stephens Creek facility along the park's northern boundary were released back into the park. The melting of snow cover which exposed residual forage, sufficient amounts of new forage, as well as the impending birth of calves, were factors in determining the timing of the release.

Upon release from the Stephens Creek facility, all 198 bison moved rapidly in a southern direction towards the park's interior ranges. The group will be closely monitored during their reacclimation process.

In 2004, operations as part of the Interagency Bison Management Plan (IBMP) resulted in the capture of 464 bison. Of those captured, 198 bison tested seronegative and were held at the Stephens Creek facility until their release today; 1 adult bull bison tested seronegative and was released after testing earlier this spring; 207 bison tested positive for exposure to brucellosis and were transported to slaughter; 1 bison died while awaiting transport to slaughter; and 57 were taken to slaughter without being tested. One adult bull bison was lethally removed.

The IBMP was signed in December 2002 by the U.S. Department of the Interior's National Park Service; the U.S. Department of Agriculture's Forest Service and Animal and Plant Health Inspection Service; and the State of Montana's Department of Livestock and Fish, Wildlife and Parks. The goal of these agencies under the IBMP is to preserve a viable, wild population of Yellowstone bison; reduce the risk of transmission of brucellosis from bison to cattle, maintain the brucellosis class-free status for the state of Montana; and protect human life and/or private property.

Under the IBMP, a variety of methods are used along the north and west boundaries of the park to manage the distribution of bison and to maintain separation of bison and cattle on public and private lands. The IBMP also allows for some bison to remain on certain public lands adjacent to the park where cattle are not grazed.

In the first phase of management, the park hazes bison approaching the north boundary to keep them inside the park and away from cattle grazing adjacent to the park. Hazing has occurred over the past several weeks on numerous occasions and will remain the first line of management when feasible. However, if attempts at hazing become ineffective and unsafe, capture operations may again become necessary.

Information provided by the NPS