Fortunately for hunters, there's plenty of overlap among the food preferences of different ducks. For instance, a choice wild rice patch that draws mallards is also likely to attract other birds, such as pintails, teal, canvasbacks and ringnecks. Wild rice is an important waterfowl food; biologists report that ducks eat it at every stage of their growth, with almost all of them feeding on its ripe grain. Sago pond weed, another important waterfowl plant, is widely believed to produce more food for ducks than any other species of aquatic plant. Geese, ducks and swans feed on sago seeds, tubers and roots. Another universal grass is smartweed. It produces abundant small, black seeds that mallards, black ducks, pintails and teal love to eat. Because the seeds are so small, smartweed can attract ducks for long periods before all the seeds are consumed.