Late in the afternoon, dozens of young Native American children arrived in a yellow school bus and galloped across a sunny field on Montana’s Blackfeet Reservation while wearing buffalo robes as if they were superhero capes.

They play-acted a long-gone Blackfeet practice of stampeding buffalo off cliffs to harvest their meat. But the only leap on this day was taken by Landen Ground, 6, who belly-flopped onto a pile of buffalo robes as if they were autumn leaves.

“Whoo! It felt like a trampoline,” he said. “You just imagine me as a buffalo.”

But buffalo are not just a figment of the imagination. Inside a large white teepee rising from a grassy hill nearby Ervin Carlson, president of the InterTribal Buffalo Council, told a crowd gathered for a treaty ceremony that bringing buffalo herds back to North America was a vital task for Native Americans — whatever the difficulties that lie ahead in ambitious plans to restoring their place in the landscape.

“We slowly have to work on it and work it out,” said Carlson, whose group has helped coordinate the return of some 20,000 buffalo to tribal land in the U.S., including the Blackfeet’s herd of about 250 that was celebrated on Tuesday at the signing of a multitribal treaty calling for even more buffalo restoration.

The group’s work has been successful. The buffalo has long been saved from extinction, and buffalo ranches are commonplace. But conservationists say that buffalo need what they call a second recovery, a return to their historic role in the ecology of North America. Buffalo till soil with their hooves and fertilize plants and spread seeds with their waste. They create living spaces for birds, prairie dogs and other small animals and feed apex predators like bears, wolves and people.