Yellowstone Late Winter Bison Population Estimate Released

Date: March 3, 2006
Contact: Nash, [phone]
Contact: Vallie, 344-2010

Yellowstone National Park has completed the 2006 late winter bison population estimate.
The late winter population is estimated to be 3500 bison.

The estimate is based on a late winter aerial survey. It takes into account the 2005 late summer population estimate of 4900 bison, known brucellosis risk management mortalities and scientific estimates of over-winter mortality rates.

The population estimate is used to guide adaptive management strategies under the Interagency Bison Management Plan (IBMP). Specific management actions may be modified based on expected late winter population levels as corroborated by the annual late winter estimate.

So far this winter, 939 bison have been removed from the wild bison population through capture operations at Stephens Creek, in accordance with the IBMP. This is the sixth winter the IBMP has been used to guide brucellosis risk management actions.

The IBMP is a cooperative plan designed to protect Montana’s brucellosis-free status while allowing for the conservation of a viable, wild bison population. Protecting Montana’s brucellosis-free status requires keeping bison from mixing with cattle grazing on land outside the park.

The five cooperating agencies operating under the IBMP are the National Park Service, the U.S. Forest Service, the Animal and Plant Health Inspection Service, the Montana Department of Livestock and the Montana Department of Fish, Wildlife and Parks.