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Pronghorn migration circuit found in Idaho

Researchers have found a migration route of pronghorn antelope that ranks among the farthest for any land mammal in the Western Hemisphere, the Wildlife Conservation Society (WCS) and the Idaho-based Lava Lake Institute for Science and Conservation, said in a news statement.

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Photo by W.B. Karesh

The 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 of more than 160 miles.

“The route crosses federal, state, and private land and narrows in one stretch to a bottleneck less than two football fields wide.

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Migration map courtesy of WCS

There, animals are restricted by mountains, fences, a highway, and fields of jagged lava from Craters of the Moon National Monument and Preserve,” WCS said.

The discovery is part of an ongoing study to track pronghorn using GPS and radio collars. Investigators include 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.”

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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, according to WCS. Once numbering in the millions, pronghorn have been reduced by some 90-95 percent although almost a million still live in the American West.

NGS photo of pronghorn by Sam Abell

To establish the newly discovered migration route, 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, WCS said.

“Growing interest in development of large-scale wind farms and their associated power lines could threaten the migration route.”

The newly discovered route is threatened by increased habitat fragmentation from development and other land-use changes, the researchers said. “Growing interest in development of large-scale wind farms and their associated power lines could threaten the migration route.”

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Both sexes sport impressive, backward-curving horns. The horns split to form forward-pointing prongs that give the species its name.

NGS photo by Bates Littlehales

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 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.”

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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, WCS said. “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.”

Watch this National Geographic Wild Chronicles video “Epic migration seen ‘through eyes’of’ antelope”. It covers the work of National Geographic grantee Joe Riis, a wildlife photojournalist and biologist who was the first to document an entire pronghorn migration on foot.

In a separate project 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,’” WCS said.

The project which led to the discovery of the new migration route 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.

National Geographic Channel will premiere an epic series about animal migrations in Fall 2010.

Related National Geographic News stories:

Rallying to Protect US Antelope Migration Route

Photos: Epic Migration Seen “Through Eyes of” Antelope

Comments

  1. Jack Hutson
    Lewiston, Idaho
    October 30, 2012, 12:03 am

    Interesting article; I enjoy antelope – America’s true one-of-a-kind specimen! But false and/or misleading statements such as, “Both sexes sport impressive, backword curving horns”. Always tend to remove credability to the writer and the organization. Simple research by anyone with a computer would have found that the female seldom “sport” horns and they are very far from “impressive” when they do.