This is my favorite kind of story — when wildlife are allowed to return to habitats they used to live in before being hunted nearly to extinction. Last week, on National Bison Day, 10 bison were reintroduced to northern Colorado, where they haven’t roamed free for more than 150 years.

The National Wildlife Federation worked to bring brucellosis-free bison to a 1000-acre parcel of open space owned by the city of Fort Collins and Larimer County. Brucellosis is a bacterial disease that can cause female bison to miscarry. Because it is possibly transmissible to domestic cattle, ranchers have long fought the reintroduction of bison in areas where their cattle might come into contact with them. The 10 bison released in Colorado last week were bred using a new technique that should guarantee they are free of brucellosis. The eventual goal is to have a herd of hundreds of bison roaming about 10,000 acres. Bison from this large herd could go on to repopulate other areas or provide fresh bloodlines to other bison herds.

Only a few bison were left in the U.S after the herds of 30 million were reduced to just a few individuals by the late 1800s. Ten bison is just a small start, but someday large herds could roam parts of Colorado again.

View the National Wildlife Federation blog post here