There was a big party on the rolling prairie of northern Colorado, and the only thing the guests of honor wanted to do was gallop away.

The roughly 200 celebrants were thrilled watching as 10 bison were introduced to their new home – a thousand acres of open space north of Fort Collins. The release on Nov. 1, National Bison Day, marked the first time wild bison have thundered across the Colorado prairie in about 150 years.

“The restoration of bison to the Soapstone Prairie Natural Area is another important step forward in the conservation of the species,” says Garrit Voggesser, the National Wildlife Federation’s national director of tribal partnerships.

The National Wildlife Federation has worked for more than two decades to restore wild bison to public and tribal lands. In March 2012, along with our tribal partners, NWF succeeded in getting 61 Yellowstone bison transferred to the Fort Peck Reservation. The next fall, 34 of those Yellowstone bison were transferred to the Fort Belknap Reservation in Montana. Then, in November 2014, an additional 134 genetically pure Yellowstone bison were restored to Fort Peck. NWF also worked with the Crane Trust in Nebraska to restore over 60, genetically-pure Yellowstone buffalo to Trust lands in February 2015.

The recent release on open space owned by the city of Fort Collins and Larimer County follows research by Colorado State University into preserving the genetically pure bloodlines of Yellowstone bison while eliminating the threat of disease. The bison in Yellowstone National Park don’t have cattle genes found in most other bison but they do have brucellosis, a disease that can cause pregnant females to abort.

There has never been a documented case of bison spreading brucellosis to livestock but the threat has prompted the policy of killing bison that wander out of Yellowstone. Any Yellowstone bison relocated to tribal or public lands would have to be quarantined for up to two years.

The Return of a Western Icon

Now, Colorado State University researchers believe they’ve found a way to rebuild populations of genetically pure, disease-free bison. The 10 bison roaming in northern Colorado include the offspring of Yellowstone bison whose embryos and semen were rid of brucellosis bacteria before artificial insemination and embryo transfer.

The long-term goal is to have hundreds of the animals roaming about 10,000 acres of prairie – and to build a herd of genetically pure, disease-free bison that can be a foundation for more herds in the West.

The day of the bison’s release, everyone was focused on the immediate: celebrating the return of a big part of the Western landscape that’s been missing for far too long.

Brian Kurzel, the National Wildlife Federation’s Rocky Mountain Regional Center executive director, and his family, including his kids Peter and Sophie, joined Voggesser at the event.

The National Wildlife Federation and partners have worked with tribes on the Fort Peck and Fort Belknap reservations in Montana to transfer Yellowstone basin to tribal lands and to get wild bison on the Wind River Reservation in Wyoming

Members of the Crow Nation in south-central Montana led prayers and songs to welcome the return of bison to its historic homeland. Listen to some of the Crow tribe members singing at the bison release.

Preserving and perpetuating the genetics of the Yellowstone bison is crucial to rebuilding wild bison populations. The Yellowstone herd is the link to an era when as many as 30 million bison wandered in huge masses across North America. After over-hunting and westward settlement, only a few wild bison were left.

A.J. Not Afraid, secretary-elect of the Crow Nation, told The Denver Post that bison are a national animal, like the eagle. He said, “Their survival depends on these conservation programs. The tribes cannot do it alone.”