Northern Prairie Wildlife Research Center
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*
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.
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).
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
*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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