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Description and Identification of American
Black Duck, Mallard, and Hybrid Wing Plumage

By

Ronald E. Kirby¹, Austin Reed², Pierre Dupuis³, Holliday H. Obrecht, III⁴, and Walter J. Quist⁵

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Abstract: We developed a key to identify wings of hybrids between American Black Ducks (Anas rubripes) and Mallards (A. platyrhynchos). Material for analysis included review of historical descriptions dating from the late 1700's, older museum collections in Europe and North America, wings collected from hunters in North America and Great Britain, birds banded in Canada and the United States, and a flock of propagated hybrids. All first filial generation (F₁) American Black Duck × Mallard hybrids were identified correctly with the key. A lower proportion of other hybrid cohorts (i.e., backcrosses of F₁ to parental forms (P₁), and second and third filial generations (F₂, F₃, etc.) were identified. We successfully identified a larger portion of male than female hybrids for all hybrid progeny cohorts examined except F₁. The new key identified 2.37 times more hybrids in the 1977 U.S. Fish and Wildlife Service Parts Collection Survey (annual determination of the species, age, and sex composition of the waterfowl harvest using detached wings contributed by hunters) than were identified by standard techniques. The proportion of American Black Duck × Mallard hybrids to the American Black Duck parental population (the ratio: hybrids/[hybrids + American Black Ducks]) may therefore be closer to 0.132 than 0.056, the historically reported value. The hybrid key is suggested for use from North Carolina north in the Atlantic Flyway and Arkansas and Tennessee north in the Mississippi Flyway (areas where other members of the Mallard group will not confound assessment). We provide suggestions for further research that would assist identification of wings in parts collection surveys and permit estimation of the proportional representation of Mallard genes in the American Black Duck gene pool.

Key Words: American Black Duck. Anas platyrhynchos, Anas rubripes, domestic Mallard, hybridization, Mallard, museum, parts collection surveys, plumage, waterfowl, wings.

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This resource is based on the following source (Northern Prairie Publication 1094):

Kirby, Ronald E., Austin Reed, Pierre Dupuis, Holliday H. Obrecht, III, and 
     Walter J. Quist.  2000.  Description and identification of American Black 
     Duck, Mallard, and hybrid wing plumage.  U.S. Geological Survey, Biological 
     Resources Division, Biological Science Report USGS/BRD/BSR-2000-0002.  
     26 pp.  

This resource should be cited as:

Kirby, Ronald E., Austin Reed, Pierre Dupuis, Holliday H. Obrecht, III, and 
     Walter J. Quist.  2000.  Description and identification of American Black 
     Duck, Mallard, and hybrid wing plumage.  U.S. Geological Survey, Biological 
     Resources Division, Biological Science Report USGS/BRD/BSR-2000-0002.  
     26 pp.  Jamestown, ND: Northern Prairie Wildlife Research Center Online.  
     http://www.npwrc.usgs.gov/resource/birds/diplume/index.htm  
     (Version 31OCT2000).

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Table of Contents

• Introduction
• Scope of the Problem
• Methods
  • Plumage Examination
  • Experimental Flock of Hybrids
• Results
  • Historical and Current Descriptions of Mallard and Black Duck Wing Plumages
    • Mallard
    • Black Duck
    • Underwing Plumage
  • Species Descriptions and Characters of Study Skins and Wings
    • Mallard Wings in Museums and Modern Parts Collections
    • Black Duck Wings in Museums and Modern Parts Collections
  • A Revised Description of Mallard Wing Plumage
  • A Revised Description of Black Duck Wing Plumage
  • Independent Confirmation of the Revised Black Duck Wing Description
  • Black Duck × Mallard Hybrid Wing Plumage
    • Hybrids Propagated at Jamestown
    • Sex Determination of Hybrid Wings
• Discussion
  • Key for Identification of Hybrid Wings
    • Identification of Domestic Mallards
    • Limitations of the Wing Key
  • What Proportion of the Hybrids in a Sample Can Be Identified?
  • Reinterpretation of the 1977 U.S. Parts Collection Survey
  • Comparison with Another Quantitative Measure of Hybridization
• The Need for Additional Research
• Acknowledgments
• Literature Cited
• Appendix

Tables and Figures

• Figure 1 -- Photograph of a typical wing from an immature male Mallard illustrating the range of dorsal and ventral characters expected in wild forms
• Figure 2 -- Dorsal and ventral photographs of a typical wing from an immature female Mallard illustrating the same features as in Figure 1
• Figure 3 -- Dorsal and ventral photographs of a typical wing from a Black Duck illustrating characters expected in wild forms
• Figure 4 -- Dorsal and ventral photographs of a wing from an adult male hybrid resembling for the most part a Black Duck
• Figure 5 -- Dorsal and ventral photographs of a wing from an immature female hybrid resembling for the most part a Black Duck
• Figure 6 -- Dorsal and ventral photographs of a wing from an adult female hybrid resembling for the most part a Mallard
• Figure 7 -- Dorsal and ventral photographs of a wing from an immature female hybrid resembling for the most part a wing intermediate between Black Duck and Mallard
• Figure 8 -- Frequency distribution of the width of white bars bounding the speculum on the wing dorsum of Black Ducks, Mallards, and hybrids

• Table -- A dichotomous key for identification of wings from American Black Ducks, Mallards and hybrids between the two

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¹ U. S. Geological Survey Northern Prairie Wildlife Research Center Jamestown, North Dakota, USA 58401
² Canadian Wildlife Service 1141 Route de l'Eglise Ste-Foy, Québec, Canada G1V 4H5
³ Canadian Wildlife Service 1141 Route de l'Eglise Ste-Foy, Québec, Canada G1V 4H5
⁴ U. S. Geological Survey Patuxent Wildlife Research Center Laurel, Maryland, USA 20708
Current address: U.S. Fish and Wildlife Service, Patuxent Research Refuge, 12100 Beech Forest Road, Laurel, Maryland 20708-4036
⁵ U. S. Geological Survey Patuxent Wildlife Research Center Laurel, Maryland, USA 20708
Current address: U.S. Fish and Wildlife Service, Northeast Regional Office, 300 Westgate Center Drive, Hadley, Massachusetts 01035

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