Waterfowl Utilization of Ponds Blasted at Delta, Manitoba

Abstract

Waterfowl use of 25 ponds blasted in Manitoba's Delta Marsh was studied from 1965-66. Greatest use of the ponds occurred during spring and early summer. In comparison to surrounding wetlands, there were greater fluctuations in annual abundance, less species diversity, and more breeding pairs per unit of shoreline on the ponds. Ducks stayed on the ponds a mean of 15.6 minutes per visit; 86 percent of their time was spent on elevated spoil. Blue-winged teal (Anas discors) comprised 56 percent of the waterfowl counted. These ponds seemingly functioned as isolation and loafing areas for breeding pairs of dabbling ducks. The declining quantity and quality of waterfowl habitats in North America has stimulated many wetland improvement projects. Scott and Dever (1940) were among the first to suggest blasting ponds as one method of improving marshlands for waterfowl. The objectives reported in this paper are: (1) to determine which species of waterfowl respond to blasting potholes; and (2) to describe how ducks use ponds blasted in a prairie marsh long inhabited by wildfowl. I wish to thank M. D. Pirnie, Michigan 1 Supported by Wildlife Management Institute, Michigan State University, Ducks Unlimited, and the Delta Waterfowl Research Station. 2 Present address: Stockbridge High School, Stockbridge, Michigan 49285. State University, for his helpful advice throughout the study; J. Rutledge, D. D. Moore, and D. P. Mossop for assisting with field work; the staff of the Delta Waterfowl Research Station, especially P. Ward and H. A. Hochbaum for their stimulating suggestions and for access to the Bell Estate.