This park and bird refuge dates from the Mississippian Period (AD 1100 to 1550). Native Americans, who roasted oysters and fished in adjacent Dauphin Island Bay, visited the shell mounds for centuries. From excavations carried out in 1990, archaeologists learned that these shell mounds were occupied according to a seasonal schedule, most often in the late winter and spring. When viewed in profile, the shell mounds are seen to contain many layers, some thick ones made up primarily of oyster shells, and intervening layers of charcoal, fish bones, and potsherds. This pattern was produced by repeated visits to the same location by small bands of people over many centuries. The modern Choctaw and Creek tribes continued to fish and harvest oysters in the area until the 1830s. Artifacts include many pieces of cooking pots broken by prehistoric occupants. Stone tools are scarce, due to the difficulty of finding tool-quality stone in the coastal plain. The park was added to the National Register of Historic Places in 1973.