WOOD RIVER, Neb. (AP) – A small herd of purebred bison has been relocated to a few square miles in central Nebraska, where vast herds once roamed over the tallgrass prairie.

The 39 cows and calves arrived Saturday at their new homes on Crane Trust land southwest of Grand Island. They were trucked in from Rimrock Ranch near Crawford in the Nebraska Panhandle. Two bulls are expected to join them this week.

“When you’re a bull, you travel on your own schedule. All a human can offer is encouragement,” said Chuck Cooper, president and chief executive officer of the Crane Trust.

The animals will make their home on more than 7 square miles of prairie, most of which has never been tilled. It’s the largest piece of tallgrass and mixed grass prairie left in Nebraska, Cooper said.

One of Crane Trust’s goals is to restore, maintain and protect natural habitat, including the sandhill and other cranes for which it is named. But experts say keeping the land in its natural state is difficult without its dominant species. Duane Hovorka, executive director of the Nebraska Wildlife Federation, said the bison will change the land and alter the relationship between the prairie and many different creatures. Biologists will study the effects.

“They’re a historic animal, and they belong here,” said Louis LaRose, of the Winnebago Tribe of Nebraska, who delivered a prayer at a ceremony on Saturday.

The bison are descended from animals that the Rimrock Ranch owner bought decades ago in Wyoming, Cooper said. Of the 500,000 bison in North America, only about 1 percent is genetically pure, descended from bison that have never been bred with cattle, experts say.