![]() The well-hidden nest, placed on the ground, is built of grasses and lined with down. In Texas Mexican Ducks are found in rivers, ponds, shallow lakes and irrigation ditches lined with emergent vegetation (Oberholser 1974). In that state, a nest with eggs was discovered April 25 with an adult with downy young observed as late as mid-September (Swarbrick 1975, Corman 2005).īREEDING HABITAT. Many Mexican Duck pairs bond or re-bond by September in Arizona, earlier than “typical” Mallards. Mexican Ducks are resident in their breeding range (Oberholser 1974, Lockwood and Freeman 2004). They are resident in Mexico from Arizona and New Mexico south on the central plateau to the central volcanic belt (Howell and Webb 1995). In the United States, these ducks also breed in south east Arizona (Corman 2005), and southern New Mexico (Am. ![]() During the 1987-1992 field work seasons of the TBBA project, volunteers found 4 confirmed, 15 probable and 4 possible breeding sites for Mexican Ducks, almost all in the Trans-Pecos region (see the region map in Lockwood and Freeman ). A more detailed discussion of the taxonomy of Mexican Duck is presented in the Systematics section of Drilling et al. These authors and others (Howell and Webb 1995) suggest Mexican Duck deserves full species status. 2001) suggests Mexican Ducks are most closely related to Mottled Ducks and these two are most closely related to American Black Ducks. A study of plumage and morphological differences in Mexican Ducks across their range indicates a clinal variation from north to south with many areas where these ducks show no evidence of hybridization (Scott and Reynolds 1983). The status of other species, also closely related to Mallards, was left unchanged although they also hybridize widely with “typical” Mallards and can be difficult to sort out (Fedynich and Rhodes 1995). Mexican Duck was considered a separate species for almost a century, but is now treated as a subspecies of the “typical” Mallard because of extensive hybridization along the United States-Mexico border (Am. rubripes) to the North American Mallard (A. A recent genetic study of dabbling ducks (Johnson and Sorenson 1999) shows the close relationship of Mottled (A. Mexican Duck and other “Mallard-like” ducks whose male plumages resemble those of female, immature and eclipse male “typical” Mallards, have always raised intriguing taxonomic questions. Because this form is identifiable, the TBBA project surveyed it separately from the “typical” Mallard.
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