Yellowstone's Summer Bison Population Estimate Released
Contact: Al Nash, 307-344-2010
Contact: Stacy Vallie, 307-344-2012
National Park Service
Yellowstone National Park
Yellowstone’s Summer Bison Population Estimate Released
Yellowstone National Park has completed the 2007 summer bison population estimate.
The summer population is estimated to be 4,700 bison. The estimate is based on a series of aerial surveys conducted in July and August.
The late-winter population was estimated at 3,600 bison in February. The population was estimated at 3,900 bison last summer. This increase is within the historical rates of the herd’s annual population increase during the summer.
This summer’s population estimate remains below the peak of 4,900 bison recorded in the summer of 2005.
The summer population estimate is used to inform 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 summer population estimate.
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.
Did You Know?
There were no wolves in Yellowstone in 1994. The wolves that were reintroduced in 1995 and 1996 thrived and there are now over 300 of their descendents living in the Greater Yellowstone Area.