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Behavioral Isolating Mechanisms In The Family Anatidae, Paul A. Johnsgard

Paul Johnsgard Collection

The ducks, geese, and swans present a host of species-recognition and isolating-mechanism problems that are equaled by few other groups of birds. As a family, the Anatidae have provided the greatest number of interspecific hybridization records of any avian family (see Gray, 1958, and Johnsgard, 1960a) both in captivity and under natural conditions. A surprising number of these hybrids have proved to be fertile, even when obtained between what appear to be well-marked genera. This remarkable capacity for hybridization indicates that isolating mechanisms must be operating effectively if species are to retain their integrity under natural conditions. Since genetic isolation …