Duck Food Plants of the Illinois River Valley

EACH year several million ducks pass through the Illinois River valley, scene of one of the greatest concentrations of migrating waterfowl in the United States. Over 90 per cent of the fall flight is made up of mallards, which have in recent years found an abundant food resource in the mechanically picked corn fields lying adjacent to the bottomland lakes. Even though corn amounts to a considerable percentage of the plant diet of the mallard,* natural waterfowl feeding grounds still are important. Diving ducks and most baldpates, gadwalls. teal and pintails, as well as large numbers of mallards, congregate principally where natural food plants are abundant. For the past 5 years the necessity for improvement of natural food beds in the Illinois River valley has been apparent. The large amount of money and effort being spent on artificial propagation of waterfowl food plants prompted the inauguration in 1937 of a study (Bellrose 1938) to determine the abundance and interrelation of aquatic plants and to discover optimum methods for management.published or submitted for publicationis peer reviewe