North America’s fastest land animal offers stiff competition in the distance category, too. Researchers from the Wildlife Conservation Society (WCS) and the Idaho-based Lava Lake Institute for Science and Conservation discovered that a group of pronghorn antelope living in Idaho have one of the longest overland migration routes in the Western Hemisphere.

The migration route stretches from the base of Idaho’s Pioneers Mountains to the continental divide’s Beaverhead Mountains, and passes through Craters of the Moon National Monument and Reserve. The round trip exceeds 160 miles and crosses federal, state, and private lands. In one stretch, it narrows to a bottleneck less than two football fields wide. There, the path is hemmed in by mountains, fences, a highway, and fields of jagged lava from Craters of the Moon National Monument and Preserve.

The discovery is part of an ongoing study to track pronghorn using GPS and radio collars. The study’s investigators include WCS’s Dr. Scott Bergen, Tess O’Sullivan of the Lava Lake Institute, and Mark Hurley of Idaho Fish and Game.

“This study shows that pronghorn are the true marathoners of the American West,” said Bergen. He added that major overland mammal migrations are becoming increasingly rare in the U.S. and elsewhere.

The researchers tracked the pronghorn’s daily movements during their annual migration. They estimated that 100–200 pronghorn currently use the migration route. During the winter, the pronghorn congregate with other regional herds from the area, making it Idaho’s largest pronghorn herd of around 1,000 animals. The GPS data collected will help the researchers better understand the pronghorn’s little-known wintering grounds.

The authors warn that the route is threatened by increased habitat fragmentation from development and other land-use changes. Growing interest in developing large-scale wind farms could further jeopardize the migration route.

“As the American West continues to face increased development pressure, preserving migratory corridors will become more and more crucial to safeguarding large populations of wildlife like pronghorn,” said Dr. Jodi Hilty, Director of WCS-North America and author of the book Corridor Ecology. “We have lost so many migrations globally, that these sorts of finds should inspire more of us to help give this uniquely American species a chance to roam in Idaho and throughout its range.”

WCS is working with ranchers, conservationists, and public lands managers to safeguard the large family ranches that have helped support this migration route over the past century. Another coalition, the Pioneers Alliance, is also working to protect ranches and farms that are part of the route.

In 2005, WCS scientists used GPS collars to document another migratory herd of pronghorn in Wyoming that travel from Grand Teton National Park to the Green River Valley. With the leadership of the U.S. Forest Service, the nation’s first designated wildlife corridor to protect the 150-mile round-trip migration of pronghorn in the Greater Yellowstone Ecosystem was created. It has since been safeguarded in a unique public/private partnership called “Path of the Pronghorn.”

Additional support for this project comes from the Bureau of Land Management, The William and Flora Hewlett Foundation, Idaho Conservation League, LightHawk Aviation, National Park Foundation, the National Park Service, The Conservation Fund, Wood River Land Trust, Carey area landowners and ranchers, The Nature Conservancy, and the Craters of the Moon Natural History Association.

Read the press release: New Long Distance Migration Route for Pronghorn Found in Idaho