Habitat use by mallard broods in south central North Dakota [Anas platyrhynchos, Game birds]

Habitat use by 25 mallard (Anas platyrhynchos) broods was determined on a study area in south central North Dakota during 1976-77. Most (89%) overland moves occurred during the first 2 weeks after hatching. Home range size increased rapidly until broods were about 1 week old, but usually stabilized during and after the 2nd week. Cumulative home range size averaged 11.0 ha and broods used from 1 to 10 wetlands during the brood-rearing period. Wetland habitat use by broods varied between years. In 1976, with favorable water conditions, mallard hens with broods preferred seasonal ponds dominated by whitetop rivergrass (Scolochloa festucacea). In 1976, use of semipermanent wetlands was significantly less than expected, whereas in 1977 during drought conditions, only semipermanent wetlands were used by mallard broods. Mallard hens selected brood-rearing sites with relatively high densities of midge (Chironomidae) larvae.