CUSTER, S.D. (AP) — The hills of Custer State Park are set to rumble as the hooves of about 1,300 buffalo thunder across the prairieland during the 47th annual Buffalo Roundup.

Thousands of spectators began to stream into the park shortly after 6 a.m. Monday to get a firsthand look at the animals as they stampede down the prairie. A pancake breakfast, hot chocolate and coffee are on offer to keep the visitors warm.

Cowboys and cowgirls are herding the buffalo into corrals at the park, where entrance is free for the day.

About 300 buffalo will be up for auction Nov. 17. The buffalo are bought to supplement or start herds, or to be eaten.