My mom and I drove the wildlife loop of Custer State Park. I wanted to photograph the bison calves. All of the animals in the park were a bit skiddish that day. Once one would start running, several would join in. We drove along watching them run. We went around a bend and saw a creek where a couple bison were drinking. I knew that the buffalo would be running over the hill to the creek very quickly. I pulled over, rolled down the window and got two shots. This was the last of the herd to go through.