Movements and Habitat Use of Franklin's Ground Squirrels in Duck-Nesting Habitat

Abstract

We used radio telemetry to determine the movements and habitat use patterns of adult Franklin's ground squirrels (Spermophilus franklinii) on a 152-ha Waterfowl Production Area (WPA) in central North Dakota. The squirrels were diurnal. Mean total distance traveled daily was 213 and 153 m for males and females, respectively. Movements of females decreased during gestation and lactation; those of both sexes decreased prior to immergence. Annual home ranges averaged 24.6 and 8.7 ha for males and females, respectively; biweekly home-range sizes exhibited seasonal patterns. Ground squirrels restricted their activities almost exclusively to the WPA. Use of blocks of herbaceous cover on the WPA could not be explained by vegetation height, density, or litter depth. Ground squirrel movements were influenced by locations of burrow systems and patchily distributed food resources. Periodic cultivation or removal of herbaceous vegetation may inhibit use of upland duck-nesting habitat by ground squirrels. J. WILDL. MANAGE. 53(2):324-331 Planting dense nesting cover (DNC) to provide upland-nesting ducks with increased security from nest predators is a common practice on areas managed for duck production in North America's prairie pothole region (Duebbert and Kantrud 1974, Duebbert and Lokemoen 1976, Higgins and Barker 1982). Although DNC is attractive to some duck species, its importance to the activities of predators of duck eggs is undetermined. The Franklin's ground squirrel inhabits dense cover throughout much of the prairie pothole region (Hall 1981). It is a predator of duck eggs (Sargeant et al. 1987) and has been implicated in severe predation on duck nests in fields of DNC in east-central North Dakota (Greenwood 1986). Past studies of Franklin's ground squirrels have emphasized natural history (Sowles 1948, Haggerty 1968, Haberman and Fleharty 1971, Iverson and Turner 1972, Murie 1973), but little information is available on their movements and use of habitat. Our objective was to describe the movements and use of habitat by Franklin's ground squirrels on a federally owned WPA where upland habitat was primarily DNC fields of different ages. We thank D. H. Johnson and J. N. Burroughs for help with data processing, R. J. Greenwood, M. A. Sovada, and D. J. Norris for field assistance and helpful suggestions throughout the study, and H. F. Duebbert and D. H. Johnson for comments on manuscript drafts. The study was funded by the U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center; the Missouri Cooperative Fish and Wildlife Research Unit; and the Edward K. Love Foundation. The U.S. Fish and Wildlife Service, Missouri Department of Conservation, University of Missouri-Columbia, and the Wildlife Management Institute contribute to the Missouri Cooperative Fish and Wildlife Research Unit. This is Journal Series 10008, Missouri Agricultural Experiment Station Project 189.