GPS collars reveal that southern Idaho pronghorn population has one of the longest overland migrations in the American West

Effort underway to protect herd numbering 1,000 animals threatened by increasing development

BRONX, NEW YORK (October 29, 2009) – Researchers from the Wildlife Conservation Society (WCS) and the Idaho-based Lava Lake Institute for Science and Conservation discovered a new overland migration route of pronghorn antelope that ranks among the farthest for any land mammal in the Western Hemisphere.

The migration route stretches from the base of Idaho’s Pioneers Mountains to the continental divide’s Beaverhead Mountains, passing through Craters of the Moon National Monument and Reserve – a round trip in excess of 160 miles. The route crosses federal, state, and private land and narrows in one stretch to a bottleneck less than two football fields wide. There, animals are restricted 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 Dr. Scott Bergen of the Wildlife Conservation Society, Tess O’Sullivan of the Lava Lake Institute of Science and Conservation, and Mark Hurley of Idaho Fish and Game.

“This study shows that pronghorn are the true marathoners of the American West,” said Scott Bergen, project director for WCS. “With these new findings, we can confirm that Idaho supports a major overland mammal migration – something that is becoming increasingly rare in the U.S. and worldwide.”

The researchers tracked the pronghorn’s daily movements during their annual migration. They estimate 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 one thousand animals.

The authors warn that the route is threatened by increased habitat fragmentation from development and other land-use changes. Growing interest in development of large-scale wind farms and their associated power-lines could threaten 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 North America Programs for the Wildlife Conservation Society, 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 100 years. The Pioneers Alliance, a coalition of landowners, ranchers, conservationists, and state and federal land managers, is working to develop conservation easements and other mechanisms to protect working ranches and farms that are part of the pronghorn migration route.

“We are committed to working with many partners, including private landowners and state and federal land managers to take the steps needed to sustain this long distance migration,” said Tess O’Sullivan, Program Director for the Lava Lake Institute.

Some of the data collected by the GPS collars will help researchers better understand – and ultimately protect – the pronghorn’s little-known wintering grounds. Data will also be used to inform the Western Governor’s Association, which continues to work toward protecting pronghorn migration. Recently the Governors of Idaho and Montana signed agreements with the Departments of Interior, Agriculture, and Energy to improve management on federal lands where pronghorn migrate. In addition, Congress has recognized the value of wildlife migrations corridors as a strategy for adapting to global warming in pending climate change legislation.

In 2005, Wildlife Conservation Society 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 migration corridor to protect 150-mile round-trip movement 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.”

This project is being supported by the Wildlife Conservation Society, Lava Lake Institute for Science and Conservation, Idaho Department of Fish and Game, 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.

Cool Pronghorn Facts

  • Lewis and Clark called pronghorn “speed goats.” They can reach speeds of 60 mph, making them second only to cheetahs in speed for land animals.
  • Researchers collar speedy pronghorns using helicopters that launch nets to temporarily capture them.
  • Once numbering in the millions, pronghorn have been reduced by some 90-95 percent although almost a million still live in the American West.
  • A previous WCS study showed the pronghorn benefit from wolves by reducing populations of coyote that normally prey heavily on pronghorn fawns.
  • WCS’s Queen Zoo recently debuted a pronghorn fawn.

The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world's largest system of urban wildlife parks, led by the flagship Bronx Zoo. Together these activities change attitudes towards nature and help people imagine wildlife and humans living in harmony. WCS is committed to this mission because it is essential to the integrity of life on Earth. Visit:

The Lava Lake Institute works to accomplish conservation and increase understanding of wildlife and ecosystems of the Pioneer Mountains – Craters of the Moon Region.

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