A study designed to determine the vegetative composition and production of that portion of Apalachee Bay, Florida, ,included within the St. Marks National Wildlife Refuge was carried out in 1964. Gizzards and gullets of fourteen diving ducks were subsequently collected in order to correlate feeding activities with available foods. Greater scaup consumed large quantities of animal foods. Redheads consumed considerably more vegetative material than animal, and showed a predilection for shoalgrass. Shoalgrass contribituted 67.9 per cent of the total volume of all foods consumed by diving ducks. Turtlegrass and manateegrass, two other species which occur commonly in the bay, apparently are of little value as waterfowl foods in this area. Vegetative production data was correllated with food habits to determine the approximate carrying capacity of the study area in waterfowl use days, and to ascertain the percentage utilization of the standing crop of vegetation by waterfowl during the 1964-65 over wintering period.
