After Yellowstone National Park’s annual summer bison population abundance monitoring, the population of bison within park boundaries are an estimated 4,600 animals. The estimate is based on a series of aerial surveys.

There are approximately 3,200 bison in the northern herd and 1,400 in the central herd this summer. There were about 700 calves-of-the-year observed in a June aerial survey.

This year’s observations represent an increase of 8.75 percent over last year’s count. The peak population estimate of 5,000 bison was recorded in the summer 2005.

The observed rate of population change this past year is within the natural range of expectation for wild bison, according to YNP press information.

This population estimate is used to inform adaptive management strategies under the Interagency Bison Management Plan, which is a cooperative plan designed to conserve a viable, wild bison population while minimizing the risk of brucellosis transmission between bison and cattle.

The 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, the Montana Department of Fish, Wildlife and Parks, the InterTribal Buffalo Council, the Confederated Salish Kootenai Tribes and the Nez Perce Tribe.