Food Habits of Common Mergansers in the Northcentral United States

A sample of 220 common mergansers (Mergus merganser) was collected from Minnesota, Nebraska and South Dakota during three years, 1966-1968. Observations of common merganser feeding behavior were made during the years 1963-1968. The sample of stomachs was obtained from fall and spring migrants, and winter residents. Sixty-seven stomachs (30 percent) of the total sample contained food items. Only 13 percent of these items could be considered game fish, the remainder were rough and forage fish. The common merganser in the Northcentral United States is not a serious predator of game fish, but is potentially a valuable game bird. The fall sample had significantly less stomachs with food items than the spring sample. Large numbers of common mergansers migrate through the Northcentral United States each spring and fall. Hundreds to several thousand mergansers over-winter in the discharge areas of the Missouri River dams. Information concerning food habits during migration and while over-wintering in the Northcentral United States is very limited. Korschgen (1952) presents some food habit data from common mergansers collected in Missouri, but his sample was small and most of the stomachs were nearly empty. Salyer and Lagler (1940) did a comprehensive study of common mergansers in Michigan and Alcorn (1953) re1 Current address: Biology Department, Minot State College, Minot, North Dakota 58701. co on ergansers t e orthcentral United ported on a study of this species in Nevada. The two latter studies involve samples drawn from drainage systems which have different habitats and fish faunas than found in the upper Missouri-Mississippi drainage. A more detailed study based on material collected in the Northeentral United States would, therefore, provide additional information. We wish to thank Game Warden L. Nelsen for his aid in collecting samples and R. R. Cody for his aid in salvaging some fall hunter kills. We are indebted to the Department of Zoology at the University of South Dakota for their financial aid during this study and to the National Aeronautics and Space Administration for their support of our graduate programs. We wish to This content downloaded from 157.55.39.159 on Sun, 18 Sep 2016 06:38:30 UTC All use subject to http://about.jstor.org/terms 88 Journal of Wildlife Management, Vol. 33, No. 1, January 1969 thank D. G. Dunlap and B. E. Harrell for their helpful suggestions concerning the manuscript.