Preferred plant foods are duck weeds, cone scales, and gall from cypress, tubers of many kinds, and the seeds of sedges, rushes, and grasses. Seeds of wild rice, smartweeds, pondweeds, and water lillies are especially preferred. Other preferred plant foods are the fruits of many trees, shrubs, and vines. These include water elm, wild grape, swamp privet, buttonbush, oaks, beech, tupelo gum, and hickories.
The wood duck is especially fond of small acorns, particularly those of water oak, Willow oak, nuttall oak, cherrybark oak, and shumard oak. In years of high production, these small acorns are the wood duck's most important winter food. Woodies search for small acorns on the forest floor and even in trees before acorns drop, but they prefer acorns that fall into shallow water--15 inches and less.
Preferred agricultural crops are browntop millet, buckwheat, corn, dove proso, foxtail millet, grain sorghum, Japanese millet, pearl millet, and soybeans. Preferred animal foods are spiders, large insects, and crustaceans. The wood duck is especially fond of spiders--sometimes spiders make up to 80 percent of the woodie's stomach content.