Animal Conservation

New UW-led report maps more big game migrations in the West | News

April 7, 2022

Two populations of mule deer featured in “Ongulate Migrations of the Western United States: Volume 2” perform cross-border migrations between wintering grounds on the Wind River Indian Reservation and summering grounds in surrounding federal lands in Wyoming. (Mark Gocke/Wyoming Game and Fish Department Photo)

There is perhaps nothing more evocative of the American West than herds of elk, mule deer or pronghorns moving freely across the landscape. And a new series of detailed maps reveal their migration routes – thanks to a team of state, federal and tribal scientists.

The second volume in a series, the detailed maps will help wildlife managers conserve the big game migrations that support herd abundance and provide cultural significance and economic benefits to regional communities.

“Many herds of ungulates must migrate to thrive in the highly seasonal landscapes of the American West. These corridor maps help manage these critical movements,” says Matthew Kauffman, a wildlife biologist at the US Geological Survey (USGS) and the University of Wyoming, who is the lead author of the report.

Every spring and fall, ungulates move across the western United States in sync with critical food resources. But, as the human footprint in the West expands, these species increasingly face obstacles such as new subdivisions, energy development, impermeable fences and heavily trafficked roads as they make their way. long journeys.

These barriers can increase mortality from vehicle collisions and disrupt historic routes used by ungulates, threatening the long-term persistence of existing migrations. Detailed mapping from GPS collar data, such as that provided in the “Western Migrations” report series, helps scientists identify these obstacles.

State and tribal wildlife agencies manage most migratory herds in the western United States. Biologists have long tracked animal movements as a cornerstone of state surveillance and management, but extracting the most biologically significant migration corridors from the tangle of individual animal tracks has been technically complex.

To meet the challenge, a partnership known as the Corridor Mapping Team was created in 2018, leveraging the expertise of national wildlife agencies, tribes, and the USGS. The corridor mapping team is made up of analysts from many western states and tribes and is led by researchers from the USGS Wyoming Cooperative Fish and Wildlife Research Unit at UW. The team has been instrumental in developing standard techniques for mapping corridors and making them available to the public.

The team’s creation and dissemination of the Migration Mapper software facilitated the production of maps for volumes 1 and 2 of “Ongulate Migrations of the Western United States”. These mapping approaches — implemented in conjunction with the Wyoming Game and Fish Department and other state wildlife agencies — have gained traction among western land and wildlife managers.

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Volumes 1 and 2 of “Ongulate Migrations of the Western United States” are available at

“The Big Game Corridor Mapping Program is strongly supported by Western fish and wildlife agencies and serves as a model of how empirical science facilitates collaborative conservation efforts at the landscape level through state cooperation. and federal,” says Zachary Lowe, executive director of the Western Association of Fish and Wildlife Agencies. “I find it hard to think of many other successful landscape conservation efforts that have garnered such broad support from these diverse stakeholders so quickly.”

Unique from the first volume, the second report in the series includes maps of two populations of mule deer that migrate through the Wind River Indian Reservation in Wyoming, which are primarily managed by the Eastern Shoshone and Northern Arapaho Departments of Fish. and Game. Other new maps delineate migrations that cross state lines, such as the Sheldon-Hart Mountain pronghorn that moves between Nevada and Oregon, and the Paunsaugunt mule deer that migrates between Utah and Arizona.

“This ungulate migration atlas is an incredible resource for anyone who cares about western big game herds and the challenges they face,” says Whit Fosburgh, President and CEO of Theodore Roosevelt Conservation. Partnership (TRCP). “TRCP appreciates the commitment demonstrated by the Department of the Interior, the USGS, and many Western states and tribes in delineating these crucial corridors.”

Many agencies and conservation groups have developed collaborative programs to support migrations by constructing underpasses or overpasses to mitigate collisions between wildlife and vehicles; remove obsolete and impassable fences; and protecting agricultural land from development.

In addition to managers from the respective national wildlife agencies, the report’s co-authors include the U.S. Forest Service, U.S. Fish and Wildlife Service, National Park Service, Eastern Shoshone and Northern Arapaho Department of Fish and Game, and the Bureau of Land Management. Maps of each herd were produced in conjunction with regional experts by mappers from the USGS and the University of Oregon’s InfoGraphics Lab. Mapping by partners is ongoing, with a third volume of migration maps currently in preparation.

The report, “Ongulate Migrations of the Western United States: Volume 2,” includes maps and summaries of 65 big game migration routes in Arizona, California, Idaho, Nevada, New Mexico, Utah, in Washington, the Wind River Indian Reservation and Wyoming. .

To explore migration routes and areas, visit the interactive portal.