The Seed and Vegetative Yield of Waterfowl Food Plants in the Illinois River Valley

Abstract

Several investigators of waterfowl food plants have suggested that the availability of a species, measured by occurrence and productivity, may largely determine its value. McAtee (1918) stated that superior availability after all is the guiding principle in the choice of foods by birds. Pirnie (1935) reiterated this theme when he said, The greater frequency with which the seeds of pondweeds and sedges occur in duck stomachs does not establish proof that these foods are preferred, for are they not most universally available? McAtee (1939) commenced his book, Wildfowl Food Plants, by a discussion of aquatic plant productivity based largely upon the vegetative or foliage measurements made by Rickett (1924). Since foliage is but part of the food produced by aquatic plants, the need for additional data on the food yields of these plants is obvious. Martin and Uhler (1939) further emphasized this need when they wrote, Little is known regarding the quantities of various wild-duck foods that can be produced in a specified water or marsh area, and reliable information is difficult to ob-