Eight bison, also known as buffalo, are becoming used to their new home at the Walnut Creek National Wildlife Refuge, 20 miles east of Des Moines near Prairie City.

The release of the bison at the wildlife refuge corresponds with National Wildlife Refuge Week, which is the first week in October, said Dick Birger, refuge manager at Walnut Creek.

The refuge currently covers about 5,000 acres. The refuge is authorized to have up to 8,600 acres.

The eight bison came from Fort Niobrara/Valentine National Wildlife Refuge in Nebraska. There is a 2-year old bull, a 2-year old cow, a yearling bull and cow, and four calves.

Birger said another six bison will be coming from Witchita Mountains, Okla., at the end of the month.

The animals are being observed in a holding pen before being released, Birger said.

“We want to see how they are doing,” he said “They’ve been taken away from home. They are young animals and we are putting them into a new area. Before it would become very difficult to catch them, we want to make sure they are doing OK.”

Birger said the bison will be important to the restoration of the prairie at the refuge. The way that bison graze is much different than domestic cattle, he said.

“Domestic cattle have had the wildness bred out of them, so they spread out more in a herd,” Birger said. “They take their time and are not afraid of predators genetically anymore. Bison are wild grazers that move in a compact pattern and they move around more.”

He said this pattern of grazing is important to prairie development. The bison “do a lot of wallowing when they find the right spot,” he said. When they develop wallows, they disturb vegetation in a small area. The disturbed area provides habitat for pioneer species of plants.

The hairy coat of the bison is a seed dispersion mechanism for some plants, Birger said. As they graze, they eat seeds. Some plants require passage through the animal’s gut in order to germinate.

Although the prairie restoration area will not formally open to the public until April, Birger said, interested people can drive through the wildlife refuge itself and may be able to see the bison after Monday, when they are released.

“Ultimately we will have 200 acres under fence,” Birger said. “We are looking at probably 150 [animals] and a lot of that is dependent on forage production. Bison have been gone so long in the eastern tallgrass prairie, and we know that the soil and rainfall here is much more conducive to forage production.”

“We don’t know what the carrying capacity for buffalo is here,” he said, “but empirically we know that the forage is so productive here, it takes less area per animal. 150 [animals] is a goal, but it is a conservative goal. We may find that we can easily support more than that but we won’t know until we’ve had a few years of study.”

A number of Iowa State researchers have been involved with the prairie restoration project including Jim Peas, Erwin Klaas and Bill Clark, all professors of animal ecology.

Clark, a member of the advisory committee to the Prairie Restoration Project, said the best thing about the bison release is the public interest that has been generated in the project, which began in 1991.

“They have been restoring grasses down there for years, but the media didn’t show up until the day the bison showed up,” Clark said. “I commented today that they don’t call them ‘charismatic megafauna’ for nothing.”