The new set of USGS maps, “Ungulate Migrations of the Western United States: Volume 4,” show the spring and fall migrations of 33 mule deer, pronghorn and elk herds.
In the Mountain West, that includes the movements of mule deer in Nevada, Utah, Colorado and New Mexico; elk in Colorado, New Mexico and Wyoming; and moose and pronghorn in Wyoming. The maps also document herds roaming tribal lands, including mule deer and elk from the Tesuque Pueblo in New Mexico, and elk from the Wind River Reservation in Wyoming. Big game in Idaho wasn’t included.
Matt Kauffman, the report’s lead author and a biologist with the USGS Wyoming Cooperative Fish and Wildlife Research Unit, said the new maps not only reveal where these animals need to go for food and water, they also show where they face obstacles.
“I'm talking about fences, and roads, more traffic on the roads, and oil and gas development,” Kauffman said. “Now, also solar and wind development, subdivisions … all these things make it more difficult for animals to move across the landscape.”
Migrating herds can tolerate moving through some level of development, said Kauffman, adding, “But what we don't know is when a threshold has been met, where there's too much development. And then you would start to see the decline of the animals that make that migration.”
Kauffman said the maps allow wildlife managers to see where conservation work is needed most as well as guide where solar and wind farms could be built without significant harms to habitats and migration routes.
So far, the Biden administration has spent more than $100 million on wildlife crossings over busy highways and other measures to protect herds in the West. In late March, the Interior Department announced it was investing $12 million to help protect migrating herds and their habitats in seven states, including Arizona, California, Colorado, Idaho, Montana, Oregon, and Wyoming.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, KUNC in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.
