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Importance of Individual Species of Predators on Nesting Success of Ducks in the Canadian Prairie Pothole Region

Douglas H. Johnson, Alan B. Sargeant, and Raymond J. Greenwood*

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We followed 3094 upland nests of several species of ducks. Clutches in most nests were lost to predation. We related daily nest predation rates to indices of activity of eight egg-eating predators, precipitation during the nesting season, and measures of wetland conditions. Activity indices of red fox (Vulpes vulpes), striped skunk (Mephitis mephitis), and raccoon (Procyon lotor) activity were positively correlated, as were activity indices of coyote (Canis latrans), Franklin's ground squirrel (Spermophilus franklinii), and black-billed magpie (Pica pica). Indices of fox and coyote activity were strongly negatively correlated (r = – 0.51), as were those of badger (Taxidea taxus) and skunk (r = – 0.46). Nest predation rates in the early part of the breeding season were positively related to indices of fox, American crow (Corvus brachyrhynchos), and badger activity. Predation rates in the latter part of the season were positively related to indices of fox and skunk activity. Predation rates on early-season nests were lower in areas and years in which larger fractions of seasonal wetlands contained water. For late-season nests, a similar relationship held involving semipermanent wetlands. We suspect that the wetland measures, which reflect precipitation during some previous period, also indicate vegetation growth and the abundance of buffer prey, factors that may influence nest predation rates.

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This resource is based on the following source (Northern Prairie Publication 0730):

Johnson, Douglas H., Alan B. Sargeant, and Raymond J. Greenwood.  1989.  
     Importance of individual species of predators on nesting success of ducks 
     in the Canadian Prairie Pothole Region.  Canadian Journal of Zoology 
     67:291-297.

This resource should be cited as:

Johnson, Douglas H., Alan B. Sargeant, and Raymond J. Greenwood.  1989.  
     Importance of individual species of predators on nesting success of ducks 
     in the Canadian Prairie Pothole Region.  Canadian Journal of Zoology 
     67:291-297.  Jamestown, ND: Northern Prairie Wildlife Research Center 
     Online.  http://www.npwrc.usgs.gov/resource/birds/dnspred/index.htm  
     (Version 26MAR2001).

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Table of Contents

• Introduction
• Study Areas
• Methods
  • Nest studies
  • Predators considered
  • Indices of carnivore activity
  • Index of Franklin's ground squirrel activity
  • Indices of crow and magpie activity
  • Weather and habitat information
  • Smoothing predator indices
  • Daily nest predation rates
  • Statistical analyses
• Results
  • Analysis of the explanatory variables
  • Analysis of daily predation rate on early nests
  • Analysis of daily predation rate on late nests
• Discussion
  • Methodological considerations
  • Interpretation of the findings
• Acknowledgements
• Literature Cited

Figures and Tables

• Figure 1 -- Study areas in the parkland and grassland portions of the Canadian Prairie Pothole Region.
• Figure 2 -- Weights used in smoothing indices of predator abundance for a quarter at the end of a study area and for an interior quarter.

• Table 1 -- Explanatory variables
• Table 2 -- Correlation coefficients between explanatory variables
• Table 3 -- Species composition of early and late clutches used in the analysis
• Table 4 -- Correlation coefficients and standardized regression coefficients relating daily predation rates of early land late clutches to explanatory variables

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*All Authors: U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, P.O. Box 2096, Jamestown, ND 58402, U.S.A.

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