Abstract

The study area of 500 km2 was humid and subtropical, on flood plain near Coraki, New South Wales. Gut contents were examined and the percentage by volume of different food items is tabulated for black duck (Anas superciliosa) and grey teal (A. gibberifrons). Black duck fed on flooded meadow-grass flats in autumn, moving when the flats dried to seasonal swamps, and when those also dried, to lagoons. Diet varied with place. Seeds of grasses, swamp plants and lagoon plants were eaten, with water snails and water beetle adults and larvae, water spiders and ostracods, and terrestrial invertebrates being eaten when the dry flats became flooded. They ate also waste maize grain from harvested fields before ploughing. Grey teal fed in the seasonal swamps in winter and then left the area almost completely; they ate almost the same items as black duck but fed by the muddy edges of seasonal swamps more than the black duck did. It was known that black duck strip seed from the growing plant and grey teal pick up the fallen seed.