Behavioral Specializations for River Life in the African Black Duck (Anas sparsa Eyton)1

Authors

  • F. McKinney,

    Corresponding author
    1. Department of Ecology and Behavioral Biology, Bell Museum of Natural History, University of Minnesota, Minneapolis, U.S.A., and Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa
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  • W. R. Siegfried,

    Corresponding author
    1. Department of Ecology and Behavioral Biology, Bell Museum of Natural History, University of Minnesota, Minneapolis, U.S.A., and Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa
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  • I. J. Ball,

    Corresponding author
    1. Department of Ecology and Behavioral Biology, Bell Museum of Natural History, University of Minnesota, Minneapolis, U.S.A., and Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa
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  • P. G. H. Frost

    Corresponding author
    1. Department of Ecology and Behavioral Biology, Bell Museum of Natural History, University of Minnesota, Minneapolis, U.S.A., and Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa
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  • 1

    This paper is dedicated to Konrad Lorenz who pioneered the use of comparative methods in the study of behavior evolution.

Bell Museum of Natural History, University of Minnesota, 10 Church St., S. E., Minneapolis, Minnesota 55455, U.S.A.

Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, Cape Province, South Africa; I. J. Ball, Department of Zoology, Washington State University, Pullman, Washington 99163, U.S.A.

Abstract

Field studies on individually marked birds near Stellenbosch, South Africa support the view that Anas sparsa is a river specialist derived from a pond-dwelling mallard-like ancestor. The key river adaptation is year-round territoriality and only established pairs breed. Mates cooperate in territory defense and both sexes engage in damaging fighting (using wing-spurs) over mates and territories. Changes in social behavior interpreted as consequences of river specialization include elimination of raping, strong development of mate-testing, mate-stealing and mate-holding tactics, and reduction of social courtship to a vestigial condition.

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