Yellowstone National Park's bison herd is healthy and productive, so much so that it's approaching the peak estimate of 5,000 animals made back in 2005.
During their annual summer aerial bison count park biologists estimated that the Northern herd contained 3,200 animals and that the Central herd numbered 1,400 for a total park population of 4,600 animals. There were about 700 calves-of-the-year observed in a June aerial survey, a park release said.
This year’s observations represent an increase of 8.75 percent over last year's count, the park noted.
The observed rate of population change this past year is within the natural range of expectation for wild bison. This population estimate is used to inform adaptive management strategies under the Interagency Bison Management Plan (IBMP). The IBMP 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.