Long-term Declines in Nest Success of Prairie Ducks

Wendy D. Beauchamp¹, Rolf R. Koford², Thomas D. Nudds³,
Robert G. Clark⁴, and Douglas H. Johnson⁵

Abstract: Increased predation on nests of ducks in prairie uplands, as a result of habitat alteration, has been hypothesized to cause decreased nest success and population sizes. We tested whether, and by how much, nest success declined using data compiled from 37 studies conducted between 1935 and 1992 at 67 sites in the Prairie Pothole Region of Canada and the United States. Nest success declined (P = 0.0002) over time, but time explained only 10% of the variation; precipitation (P = 0.79) did not account for additional variation in nest success. Nest success declined at similar (P = 0.13) rates among 5 species, but late nesters (gadwall [Anas strepera], blue-winged teal [A. discors], and northern shoveler [A. clypeata]) had higher success (P = 0.004) than early nesters (mallard [A. platyrhynchos], and northern pintail [A. acuta]). Populations of gadwalls and northern shovelers, however, have not declined, indicating that declines in nest success may not be related causally to population change. Long-term population declines in blue-winged teal, northern pintails, and mallards coincide with large-scale temporal declines in nest success. Declines in nest success were parallel in parkland and grassland regions, suggesting a causal agent (or agents) that act(s) at a broad scale, despite inherent differences in the composition of the predator communities and habitats between regions.

Key words: conserved soil moisture, habitat fragmentation, long-term data, nest success, population decline, Prairie Pothole Region, upland habitat, waterfowl.

This resource is based on the following source (Northern Prairie Publication 0962):

Beauchamp, Wendy D., Rolf R. Koford, Thomas D. Nudds, Robert G. Clark, 
     and Douglas H. Johnson.  1996.  Long-term Declines in Nest Success 
     of Prairie Ducks.  Journal of Wildife Management 60(2):247-257.

This resource should be cited as:

Beauchamp, Wendy D., Rolf R. Koford, Thomas D. Nudds, Robert G. Clark, 
     and Douglas H. Johnson.  1996.  Long-term Declines in Nest Success 
     of Prairie Ducks.  Journal of Wildife Management 60(2):247-257.  
     Jamestown, ND: Northern Prairie Wildlife Research Center Online.     
     http://www.npwrc.usgs.gov/resource/birds/decline/index.htm 
     (Version 17FEB2000).

Introduction
Methods
- Nest Success Data
- Transforming Apparent Nest Success Estimates
- Precipitation Data
- Statistical Analysis
Results
Discussion
Management Implications
Acknowledgments
Literature Cited
Appendix A

¹ Zoology Department, University of Guelph, Guelph, ON N1G 2W1, Canada. Present address: Wildlife Ecology Research Group, Canadian Wildlife Service, 5421 Robertson Rd., R.R.1, Delta, BC, V4K 3N2, Canada.
² National Biological Service, Northern Prairie Wildlife Research Center, Jamestown, ND 58401, USA. Present address: Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames, IA, 50011, USA.
³Zoology Department, University of Guelph, Guelph, ON N1G 2W1, Canada.
⁴Canadian Wildlife Service, Prairie and Northern Wildlife Research Center, 115 Perimeter Road, Saskatoon, SK S7N 0X4, Canada.
⁵National Biological Service, Northern Prairie Wildlife Research Center, Jamestown, ND 58401, USA.

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