The abundance of various species of wildlife in marshes and ponds influenced by weirs was measured and compared to similar data collected on non-wetTed or control areas from January through December, 1974. Weirs were constructed in marsh drainage systems and held water levels in ponds and bayous several inches below the elevation of the adjacent marsh; however, control areas were subjected to natural tidal influences. Greater duck, coot, and non-game bird usage was found in ponds influenced by weirs, especially during low water periods occurring in the winter. Field data indicated that weirs had no measurable effects on fur bearer or small mammal populations, with the exception of swamp rabbits. Whether populations were high or low was generally independent of the influence of weirs in the areas surveyed. Survey methods most reliable were aerial bird counts and ground counts of muskrat beds and nutria trails.