Food Use by Migratory Female Mallards in Northwest Missouri

We studied foods of migratory female mallards (Anas platyrhynchos) relative to habitat and molt during fall 1984 and 1985 in northwest Missouri. Females consumed primarily plant foods in moist-soil, arrowhead (Sagittaria latifolia), and mixed habitats (mixtures of moist-soil and arrowhead plants), but the importance of individual foods varied among habitats. Seeds of wild millet (Echinochloa spp.) and nodding smartweed (Polygonum lapathifolium) accounted for 85% of the mallard diet in moist-soil habitat, whereas seeds and tubers of arrowhead comprised >40% of the diet in arrowhead habitats. These foods and rice-cutgrass (Leersia oryzoides) seeds were important in mixed habitats. Invertebrates comprised 1.6, 6.3, and 17.1% of the diet by mass for females from moist-soil, mixed and arrowhead habitats, respectively. Invertebrate consumption was not correlated with intensity of molt and did not vary with molt completion. Diets of female mallards collected at roosts during fall and spring consisted of primarily agricultural foods