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Population Dynamics of Breeding Waterfowl

Douglas H. Johnson, James D. Nichols, and Michael D. Schwartz

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I. Introduction

The breeding season is of paramount importance to the population dynamics of waterfowl. All of the increase to a population occurs, as does much of the mortality during that season, which is often but a fraction of the entire year. Considerable research effort has been expended to better understand the dynamics of breeding waterfowl populations; much of this attention has been directed toward management activities to increase numbers in hunted populations.

This chapter reviews what is known about the dynamics of breeding waterfowl populations. Most of the literature surveyed (virtually all in English) pertains to a relatively few common and popular forms of ducks and geese, and to temperate- or arctic-zone habitats in North America and Europe. Some comparisons with tropical and Southern Hemispheric species help illustrate the diversity found among waterfowl.

We treat several components of total reproductive output: 1) the number of potential breeding birds, 2) the proportion of individuals that attempt to breed, 3) clutch size, 4) egg survival, and 5) survival of young. We also discuss 6) composite reproductive statistics, which combine two or more of these components into one measure of reproductive rate. For these quantities, we try to present typical values, illustrate the variation found in nature, and identify the factors associated with variation, be they inherent in the bird or environmentally determined. Common factors include species, age and breeding experience, condition of the bird, social status, and other individual effects, as well as geography, wetland habitat conditions, nesting habitat, weather, and population density. We further attempt to determine the components most influential in the dynamics of waterfowl populations and to identify the factors that consistently have important effects on those components.

Many of the components of recruitment relate directly to subjects presented elsewhere in this volume. Where possible, we refer the reader to pertinent chapters for a more detailed treatment. One key component of breeding-season dynamics, the survival of adults during the breeding season, is completely omitted here, for it is the focus of chapter 12.

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This resource is based on the following source:

Johnson, Douglas H., James D. Nichols, and Michael D. Schwartz.  1992.
     Population dynamics of breeding waterfowl.  Ecology and Management
     of Breeding Waterfowl.  University of Minnesota Press, Minneapolis,
     MN.  Chapter 14:446-485.

This resource should be cited as:

Johnson, Douglas H., James D. Nichols, and Michael D. Schwartz.  1992.
     Population dynamics of breeding waterfowl.  Ecology and Management
     of Breeding Waterfowl.  University of Minnesota Press, Minneapolis,
     MN.  Northern Prairie Wildlife Research Center Online. 
     http://www.npwrc.usgs.gov/resource/birds/ecomanag/popdynam/popdynam.htm
     (Version 02FEB99).

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Table of Contents

• Number of Potential Breeding Birds
  • Survival
    • Species
    • Age
    • Sex
    • Condition and Social Status of the Bird
    • Geographic Variation
    • Wetland Habitat and Weaather
    • Population Density
  • Homing and Pioneering
    • Species
    • Age and Breeding Experience
    • Sex and Pair Status
    • Wetland Habitat and Population Density
  • Synopsis
• Proportion of Birds that Attempt to Breed
  • Age of Reproductive Maturity
  • Timing of Breeding
    • Species and Geographic Variation
    • Age, Breeding Experience, and Condition
    • Wetland and Nesting Habitat
    • Weather
    • Other Factors
  • Initial Breeding and Renesting
    • Age and Breeding Experience
    • Condition and Social Status of the Bird
    • Wetland Habitat and Weather
    • Density of Birds and Individual Differences
  • Synopsis
• Clutch Size and Egg Size
  • Clutch Size
    • Seasonal Decline in Clutch Size
    • Age and Breeding Experience
    • Condition of the Bird and Wetland Habitat
    • Nesting Habitat and Weather
    • Parasitism and Other Factors
  • Egg Size
  • Synopsis
• Egg Surivial
  • Nest Success
    • Age, Breeding Experience, and Condition of the Bird
    • Nesting Habitat
    • Density and Parasitism
    • Humans and Weather
    • Other Factors
  • Losses of Individual Eggs
    • Infertility
    • Embryonic Death
    • Predation
  • Sex Ratio of Hatching Young
  • Synopsis
• Survival of Young
  • Age and Breeding Experience
  • Density, Crèching Behavior, and Brood Size
  • Wetland Habitat
  • Timing of Hatch
  • Attentiveness of Parent
  • Indirect Effects
  • Synopsis
• Composite Reproductive Statistics
  • Species and Geographic Variation
  • Age, Breeding Experience, and Social Status
  • Wetland Habitat
  • Weather
  • Density of Birds
  • Synopsis
• Discussion
  • Critical Components
    • A Model
    • Influence of the Components
    • Example -- Mallards in the Prairie Pothole Region
    • Example -- Snow Geese in the Arctic
    • Example -- Southern Wood Duck
    • The Three Populations Contrasted
  • Recommendations for Future Research
    • Components of Population Dynamics
    • Inherent and Environmental Influences on the Components
    • Study Approaches
  • Management Considerations
• Acknowledgments
• References

Tables

• Table 1 -- Annual survival rate estimates of North American Anatidae.
• Table 2 -- Reported incidence of egg loss in successful nests of waterfowl species.
• Table 3 -- Observed brood-pair ratios of North American waterfowl.
• Table 4 -- Standardized regression coefficients for three modeled populations.

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