Some Factors Influencing the Abundance of Waterfowl Along the Mississippi River in Iowa

In order to determine some of the factors influencing waterfowl abundance in eastern Iowa, field studies were made of migrating ducks during the years 1940-1945. A study area was selected on the Mississippi River 20 miles north of Davenport, Iowa, and near the town of Princeton, Iowa. The study area, a low-land meadow and marsh, is 5 miles in length and 1½ miles in width. It is known locally as the Princeton Marsh. Additional observations were made at scattered points along the Mississippi from Dubuque south to Keokuk, Iowa; on the Wapsipinicon River for a few miles above its mouth; and on Rock River near Moline, Illinois