Sage-grouse need large, connected, and mostly treeless swaths of sagebrush to survive. Without this, sage-grouse cease to exist. It’s that simple. Sage-grouse are what scientists and biologists call a sagebrush obligate species. You can’t have sage-grouse without sage.
Sage-grouse occupy western sagebrush (Artemisia sp.) prairies of California, Nevada, Oregon, Washington, Idaho, Utah, Colorado, Wyoming, Montana, North Dakota, South Dakota, and into the province of Saskatchewan. Although sage-grouse still live in all these places, their populations have shrunk. The largest core populations still thrive in Montana, Wyoming, Idaho, Nevada, and Oregon. Uncoincidentally, these are the same states with the most intact and healthy sagebrush landscapes.