A waterfowl decoy apparatus provides simulated head pumping movement of a bird's head in an up and down vertical path defined by a cam support and cam follower rod. A cam follower rod with flat base is inserted into a holed frame which sits on an off center cam. The cam supports the decoy head positioned on the cam follower rod, and a small battery operated motive device moves the off center cam in circular direction. This cam mechanism causes the decoy head to move in an up and down vertical motion. In addition an alternative method for decoy head to move in a vertical path is defined by a “level wind” mechanism having a channel guide mounted for traversing a reversible groove shaft by means of a follower as the shaft is rotated. The device is mounted and enclosed inside a hollow duck decoy with a detachable back to access internal components.