Places We Protect

Shirley Basin

Harboring some of the world’s last intact grasslands.

The Shirley Basin is a vast and ever changing landscape.
Shirley Basin The Shirley Basin is a vast and ever changing landscape. © Scott Copeland

Black-footed ferrets—widely considered the most endangered mammal in the United States—were reintroduced into the Shirley Basin in 1991. Their reintroduction into the basin’s open sagebrush country has catalyzed black-footed ferret survival in other parts of the West.
Like all native species, the black-footed ferret is a crucial piece in a complex biological jigsaw puzzle. Every piece is essential to make the puzzle complete—the ecological integrity of the entire Shirley Basin depends on the small predator with its distinctive sleek body and black paws.

Southeastern Wyoming, south of the Medicine Bow National Forest

More than one million acres

What to See: Plants
The Shirley Basin is a surprising blend of mixed-grass prairie and Wyoming big sage communities, interspersed with saltbush flats, greasewood, aspen, and ponderosa, lodgepole and limber pine. Shrubs dominate along the basin’s river banks, providing important habitat for nesting birds.

What to See: Animals
With one of the largest existing colonies of white-tailed prairie dogs, the Shirley Basin is a natural fit for the prairie dog’s primary predator—the black-footed ferret. Wild ferret behavior revolves around prairie dog towns, where ferrets hunt in loping bounds from one burrow to the next. The Shirley Basin also supports superb fisheries, significant bat roosts, and numerous bird species, including mountain plover, ferruginous hawks, sage grouse and the American white pelican.

Why the Conservancy Selected this Site
Only two percent of the world’s grasslands are under some sort of formal protection. Conservancy scientists have identified the Shirley Basin as an area of high biological significance. The basin’s intact grasslands and aquatic habitats offer an enormous conservation opportunity, especially for the management and protection of black-footed ferrets. Much of this habitat sits on large tracts of private lands where long-term protection can still be achieved across a large landscape.

What the Conservancy Has Done/Is Doing
Conservation easements are among the best tools for achieving lasting conservation results in the Shirley Basin. In the Laramie River area, rapid residential development spreading out from Laramie makes conservation easements particularly valuable for maintaining the landscape’s rural character. Stewardship activities that restore healthy fire regimes and treat invasive plant species are also key to conserving the Shirley Basin’s lands and waters.

Help Protect Wyoming's Grasslands

Support our work in Wyoming, including the protection of our grassland ecosystems near Shirley Basin, by making a charitable contribution today.