Foods of breeding pintails in North Dakota

Food habits of breeding pintails (Anas acuta) were studied relative to sex, land use, and reproductive condition during the spring and summer of 1969, 1970, and 1971 in eastern North Dakota. Hens and drakes, respectively, consumed 79.2 percent and 30.0 percent animal matter on nontilled wetlands and consumed 16.6 percent and 1.1 percent animal matter on tilled wetlands. Aquatic dipterans (primarily larval forms), snails, fairy shrimp, and earthworms accounted for 71 percent of the diet of hens on nontilled wetlands, while barnyard grass (Echinochloa crusgalli) seeds formed 71 percent of the diet of hens on tilled wetlands. Cereal grain seeds formed 84 percent of the diet of 10 hens feeding on cropland. The diet of hens was influenced by reproductive status. Animal foods were predominant during the laying period (77.1 percent) but were less important in the postlaying diet (28.9 percent). Invertebrates formed 83.9 percent of the diet of renesting hens, 61.0 percent were dipteran larvae and snails. High consumption of animal foods during egg formation presumably is related to invertebrates being superior to plants in providing certain nutrients required for production of viable eggs. Research findings suggest that food requirements of prairie-nesting pintails can be met most effectively by providing pairs access to shallow, nontilled wetland habitat subject to periodic drawdowns.