I remember standing on a bluff above Lake Oahe in central South Dakota one November day when a strong north wind was blowing and the ducks were coming down from Canada.

They appeared as long skeins of tiny specks high up under the clouds. The lines proceeded halfway across the sky and then collapsed into a downward spiral that darkened as the ducks swirled closer, looking like the twisting tail of a tornado. Thousands of mallards were piling into newly picked cornfields. The ground was black with the feeding ducks.

“Tomorrow you’re going to see the best duck hunting of your life,” promised my guide, Mike McClelland (605-223-9126) of Pierre, smack in the center of South Dakota’s best waterfowl action.

Before daylight the next morning we were tearing across the prairie in McClelland’s Suburban with an aluminum boat bouncing behind, headed toward a tiny spot he had selected on a map of South Dakota waterfowl production areas.

We drove to a marked public access site and got out in the predawn murk. The air was full of the sounds of mallards quacking, splashing, chuckling. Hundreds of birds were packed into a shallow cattail-rimmed pothole no more than a quarter mile long. We loaded the decoys, guns, and dogs into the boat and pushed out across the open water. Waves of mallards exploded into the air ahead of us and disappeared in the distance. “Don’t worry,” McClelland said. “They’ll be back.”

We scattered three dozen decoys just upwind of where we’d hidden the boat and took stands in the head-high cattails. Almost immediately, mallards began returning in flocks of five to 25. A few hail calls, quacks, and feeding chuckles was all it took to steer them over the decoys. Before the dogs could finish retrieving the ducks that we dropped in one salvo, another bunch of mallards would show up.

It’s like that in South Dakota from the time when the ducks come down from Canada in November until deep snow covers up the feed. They crowd into the potholes for the night, fly out to grainfields to eat for a while, and then return to wherever they spent the night to rest and drink. This constant shuttling back and forth creates overwhelming shooting opportunities.

South Dakota has more than 1,000 pothole waterfowl production areas that have been purchased by the U.S. Fish and Wildlife Service with funds from duck-stamp sales. Many are remote and attract very little hunting pressure. You can find them clearly marked on maps available from the South Dakota Department of Game, Fish and Parks, 605-773-3485;