Waterfowl Breeding Habitat in Agricultural and Nonagricultural Land in Manitoba

Abstract

Waterfowl populations and habitat characteristics were examined on 33 potholes in each of two 16-square-mile study areas of agricultural and nonamoultural land in southwestern Manitoba. The agricultural land potholes, lacking in or incompletely surrounded by trees received greater use by lesser scaup (Aythya affinis), canvasback (A. valtsineria), redhead (A. americanaj, coot (Fulica americana), and three species of grebes (Podicipedidae). The nonagricultural land potholes, completely surrounded by trees, were more attractive to blue-winged teal (Anas discors), and mallard (A. platyrhynchos), and over twice as many dabbler broods were censused there. Abundant, undisturbed nesting cover may have been the reason for greater dabbler use on the nonagricultural land potholes since chemical and biological properties suggest more fertile conditions in the agricultural land. Borden and Hochbaum (1966:8S) state that the aim of waterfowl management should be to produce more ducks per square mile on the remaining waterfowl habitat in North America in order to counteract the adverse affects of drainage and intensified land use. A study of waterfowl habitat in two separate areas, one where man is the dominant factor and the other where his presence is of minor importance, is necessary to document just how man is affecting waterfowl production. The objectives of this paper are: ( 1) to contrast waterfowl use and production on agricultural and nonagricultural land in the aspen parkland of Manitoba; (2) to assess some characteristics of pothole habitat for waterfowl production in the two areas. The study reported here was based on intensive field work carried out from April 23 to August 31, 1968, after 3 months were spent in 1967 selecting study areas and carrying out preliminary observations. I am indebted to R. A. McCabe and H. A. Hochbaum for advice and encouragement during the study. Thanks are due the Riding Mountain National Park staff 1 A contribution of the Delta Waterfowl Research Station and the Department of Wildlife Ecology, University of Wisconsin. 2 Present address: Noriern Prairie Wildlife Research Center, Jamestown, North Dakota. 130 for providing living quarters and a saddle horse during the study and especially Warden and Mrs. R. Dowhan for their hospitality and friendliness. Special thanks are due R. J. Blohm for help with the field work and to J. J. Hickey, H. W. Miller, P. F. Springer, and H. K. Nelson for advice on the manuscript. HABITAT CHARACTERISTICS