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

Methods

We reviewed historical (1758 - present) descriptions of Mallard and Black Duck wing plumage to establish standards for comparison. We confirmed species and hybrid characters through inspection of wings from Mallard populations that probably had little or no contact with Black Duck populations, including the collections of 11 museums (Smithsonian Museum of Natural History, Washington, D.C.; American Museum of Natural History, New York, New York; Academy of Natural Sciences, Philadelphia, Pennsylvania; Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts; Royal Museum of Natural History, Toronto, Ontario; Museum of Natural History of Canada, Ottawa, Ontario; Wildfowl Trust, Slimbridge, Gloucestershire, England; Harrison Museum, Seven Oaks, Kent, England; British Museum, Tring, Hertfordshire, England; Royal Scottish Museum, Edinburgh, Scotland; and the Allison Collection, Loch Leven, Kinross, Scotland). We further evaluated species and hybrid characters in live-trapped birds from Thurso, Québec (1974-76), New Jersey (1976-78), and Maine (1977-78) and parts collection survey receipts from three countries and a number of years (Canadian Parts Collection Surveys 1975-76, 1976-77, 1977-78, 1978-79; U.S. Atlantic Flyway 1976-77, 1977-78, 1978-79; U.S. Pacific Flyway 1976-77; British Parts Collection Survey 1976-77). We also examined an experimental flock of 248 Black Duck × Mallard hybrids. Finally, we developed a key for identifying hybrid forms and reanalyzed Mallard-like and Black Duck-like wings obtained in the 1977 U. S. Parts Collection Survey.

Plumage Examination

We used a subsample of the live birds and whole-body study skins to compare plumage characters with published descriptions. For each bird, we initially sorted data for 42 individual feathers or feather tracts by size, shape, color, and internal patterns within feathers as part of an ongoing study in Canada (P. Dupuis, unpublished data). We compared areas of white on the wing dorsum to a Mallard standard (e.g., a male and female wing showing the characters illustrated in Carney 1992: Figs. 3 and 4). We examined additional specimens for only wing characters, although other aspects of the plumage, if unusual, were noted qualitatively. We analyzed plumage criteria in the same fashion for the large numbers of wings obtained from the annual parts collection surveys. We also analyzed specimens of Mottled Ducks (A. fulvigula) and Mexican Ducks (A. diaza=diazi group of A. platyrhynchos of American Ornithologists' Union 1998) whose ranges partially overlap those of Black Ducks and Mallards. In order to quantify the total range of variation in the collections, we likewise evaluated all specimens in the 11 museum collections that were identified in the catalogues or on the specimen labels as Anas spp. hybrids, domestic breeds, or unusual varieties.

Experimental Flock of Hybrids

In the early 1970's, F. B. Lee reared a captive flock of P1 Mallards from California and North Dakota and P1 Black Ducks from New Brunswick (some hand-reared in North Dakota) at Northern Prairie Wildlife Research Center near Jamestown, North Dakota. In 1974-76, a breeding program was established to develop various hybrids from these parental forms. Following a series of related studies, the hybrid flock became available for our use in November, 1976, when we examined them and compared them with wild birds shot by hunters and reported to the U.S. Parts Collection Survey. We made study skins of representative individuals and entered them into the collections of the Smithsonian Museum of Natural History.

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