Waterfowl Use and Production of Artificial Nesting Structures and Hay Bales in South Dakota

Habitat degradation and subsequent reductions in North America waterfowl populations have renewed interest in artificial nesting structures as a means to increase waterfowl production in the Prairie Pothole Region. I evaluated waterfowl use and nesting material durability of 3 types of artificial nesting structures and hay bales in 16 eastern and north-central South Dakota counties in 1988 and 1989. Of 443 structures and bales only 180 in 1988 and 271 in 1989 occurred in water and were suitable for use by waterfowl. Data were collected during 4 nest searches conducted at approximately monthly intervals from May through August each year. Drought conditions in 1988 and 1989 negatively affected breeding bird abundance and species composition, range of nest initiation and structure occupancy. Mean actual occupancy and nesting success for ducks and geese on all structure types combined was 35. 3% and 70. 1%, respectively. Actual structure occupancy averaged highest on bales (31. 6% for ducks, 36. 8% for geese), followed by culverts (21. 1% for ducks, 33. 3% for geese) and baskets (12. 8% for ducks, 11. 2% for geese). Nesting success averaged highest on culverts (91. 7% for ducks, 100. 0% for geese), followed by baskets (79. 4% for ducks, 96. 6% for geese) and bales (25. 0% for ducks, 78. 4% for geese). Known number of ducklings produced per usable structure in water averaged 1. 4 on culverts, 0. 8 on baskets and 0. 6 on bales, while known number of ducklings produced per occupied structure averaged 6. 4 on culverts, 6. 1 on baskets and 2. 0 on bales. Known number of goslings produced per usable structure in water averaged 1. 1 on culverts, 0.9 on bales and 0. 1 on baskets, while known number of goslings produced per occupied structure averaged 3. 2 on culverts, 2. 5 on bales and 1. 0 on baskets. Structure occupancy increased with water depth, distance from shore and density of structures per hectare (acre) of wetland area. There were no significant differences of mallard occupancy, nesting success or egg hatchability on green-dyed vs. natural colored materials; although nest initiation on green-dyed materials averaged 10 (1989) to 14 days (1988) earlier than on natural-colored materials. My bale depreciation data indicated that bales should be replaced every 2 or 3 years. The most durable bale material type was flax straw. Future research should concentrate on additional designs and nesting materials that increase occupancy rates. Especially worthy of attention are self-maintaining (low maintenance) types and green-dyed nesting materials. Means should also be explored to increase the durability of round bales as nesting structures