Mule deer can be found from central Mexico to northwestern Canada. They can also be found to inhabit land as far east as Kansas and Nebraska. In these areas, buildings are being constructed which is causing habitat loss.
The mule deer population has been dropping rapidly. Wyoming had about 578,000 deer in 1991. In 2012, the number dropped to 369,000, a 36 percent difference in only two decades. A dramatic decrease also occurred in Colorado.
In 1998, 17 states and four Canadian provinces formed a wildlife committee to find a solution. The committee determined that the reason for the decrease in mule deer population was due to home construction and energy development.
Another factor resulting in their lowered population is wildfires. These fires burn down cheatgrass, which the mule deer rely on for food. Even though it is a small portion of their diet, its loss is a big matter. Many deer don't have enough food to survive.
Unfortunately, there is no way to recover the lost deer, but there are ways to protect those that remain. Organizations like the National Wildlife Federation work to protect the habitat of mule deer.