Redhead Aythya americana Scientific name definitions

This diving duck, restricted to North America, breeds widely throughout the Prairie Pothole Region of the United States and Canada. It also nests in dense concentrations in marshes of the western United States. In contrast to its extensive breeding distribution, the Redhead in winter is concentrated mostly in coastal areas along the Gulf of Mexico, with hundreds of thousands of birds traditionally found in the Laguna Madre of Texas and the Laguna Madre of Tamaulipas, Mexico.

The Redhead begins arriving in its winter range in October. The species depends heavily on rhizomes of shoalgrass (Halodule wrightii), a seagrass species, for winter nutrition. Pairs begin to form on the winter range, and by the time the last birds have left on their northward migration in March, pair formation is well under way. Monogamous pair bonds continue developing rapidly in small migrating flocks, with birds initiating nesting by early May and extending at least into late June. Nests are constructed in dense emergent vegetation (usually cattail [Typha] or bulrush [Scirpus] spp.) of deep marshes.

The Redhead demonstrates facultative brood parasitism to a greater extent than any other North American duck. A breeding female chooses 1 of 3 laying strategies: (1) lays her own clutch, (2) parasitizes other nests before laying her clutch, or (3) parasitizes other duck nests without producing a clutch of her own. Inter- and intraspecific egg parasitism is very common with this species; parasitic egg-laying has been known to increase nest abandonment and depress clutch size, nest success, and egg success for some host species. Males usually abandon their mates early in incubation, after which they and unsuccessful females congregate in large flocks on Canadian lakes to undergo molt and to stage for fall migration.

This wide-ranging species exhibits a high degree of flexibility in habitat and food use and reproductive behavior, yet, paradoxically, its numbers consistently are surpassed by populations of most other prairie-nesting ducks of North America. Many aspects of Redhead biology are well known: e.g., timing and routes of continental migration, courtship behavior, and pairing chronology (Weller Weller 1964a Weller, M. W. (1964a). Distribution and migration of the Redhead. Journal of Wildlife Management 28:64-103. Close , Weller 1965b Weller, M. W. (1965b). Chronology of pair formation in some of the Nearctic Aythya (Anatidae). Auk 82:227-235. Close , Weller 1967a Weller, M. W. (1967a). Courtship of the Redhead (Aythya americana). Auk 84:544-559. Close ; Johnsgard 1965 Johnsgard, P. A. (1965). Handbook of Waterfowl Behavior. Cornell University Press, Ithaca, New York, USA. Close ; Bergman 1973 Bergman, R. D. (1973). Use of southern boreal lakes by postbreeding Canvasbacks and Redheads. Journal of Wildlife Management 37:160-170. Close ); nesting ecology, reproductive biology, breeding habitat, and brood parasitism in Utah, Iowa, Manitoba, Montana, and North Dakota (Williams and Marshall 1938 Williams, C. S. and W. H. Marshall. (1938). Duck nesting studies, Bear River Migratory Bird Refuge, Utah, 1937. Journal of Wildlife Management 2:29-48. Close ; Low 1945 Low, J. B. (1945). Ecology and management of the Redhead, Nyroca americana, in Iowa. Ecological Monographs 15:35-69. Close ; Weller 1959b Weller, M. W. (1959b). Parasitic egg laying in Redhead (Aythya americana) and other North American Anatidae. Ecological Monographs 29:333-365. Close ; Lokemoen Lokemoen 1966 Lokemoen, J. T. (1966). Breeding ecology of the Redhead duck in western Montana. Journal of Wildlife Management 30:668-681. Close , Lokemoen 1991 Lokemoen, J. T. (1991). Brood parasitism among waterfowl nesting on islands and peninsulas in North Dakota. Condor 93:340-345. Close ; Kantrud and Stewart 1977 Kantrud, H. A. and R. E. Stewart. (1977). Use of natural basin wetlands by breeding waterfowl in North Dakota. Journal of Wildlife Management 41:243-253. Close ; Sorenson 1991 Sorenson, M. D. (1991). The functional significance of parasitic egg laying and typical nesting in Redhead ducks: an analysis of individual behaviour. Animal Behaviour 42:771-796. Close ; Sayler 1996 Sayler, R. D. (1996). Behavioral interactions among brood parasites with precocial young: Canvasbacks and Redheads on the Delta Marsh. Condor 98:801-809. Close ). Recent advances have been made in estimating survival of Redhead ducklings and females (Yerkes 2000a Yerkes, T. (2000a). Influence of female age and body mass on brood and duckling survival, number of surviving ducklings, and brood movements in Redheads. Condor 102:926-929. Close , Arnold et al. 2002 Arnold, T. W., M. G. Anderson, M. D. Sorenson and R. B. Emery. (2002). Survival and philopatry of female Redheads breeding in southwestern Manitoba. Journal of Wildlife Management 66:162-169. Close ); time-activity budgets in winter in Texas, Louisiana, and Tamaulipas (Mitchell et al. 1992 Mitchell, C. A., T. W. Custer and P. J. Zwank. (1992). Redhead duck behavior on lLower Laguna Madre and adjacent ponds of southern Texas. Southwestern Naturalist 37:65-72. Close , Michot et al. 1994b Michot, T. C., E. B. Moser and W. Norling. (1994b). Effects of weather and tides on feeding and flock positions of wintering Redheads in the Chandeleur Sound, Louisiana. Hydrobiologia 279/280:263-278. Close , Woodin 1994 Woodin, M. C. (1994). Use of saltwater and freshwater habitats by wintering Redheads in southern Texas. Hydrobiologia 279/280:279-287. Close , Adair et al. 1996 Adair, S. E., J. L. Moore and Jr. Kiel, W. H. (1996). Wintering diving duck use of coastal ponds: an analysis of alternative hypotheses. Journal of Wildlife Management 60:83-93. Close , Vázquez et al. 1996 Vázquez, M. A., H. Suzán and M. Woodin. (1996). Comportamiento invernal del pato cabeza roja (Aythya americana) en la Laguna Madre de Tamaulipas, Mexico. Biotam 7:25-30. Close ); foods and foraging ecology of breeders (Bartonek and Hickey 1969a Bartonek, J. C. and J. J. Hickey. (1969a). Food habits of Canvasbacks, Redheads, and Lesser Scaup in Manitoba. Condor 71:280-290. Close , Noyes and Jarvis 1985 Noyes, J. H. and R. L. Jarvis. (1985). Diet and nutrition of breeding female Redhead and Canvasback ducks in Nevada. Journal of Wildlife Management 49:203-211. Close , Jarvis and Noyes 1986 Jarvis, R. L. and J. H. Noyes. (1986). Foods of Canvasbacks and Redheads in Nevada: paired males and ducklings. Journal of Wildlife Management 50:199-203. Close , Woodin and Swanson 1989 Woodin, M. C. and G. A. Swanson (1989). Foods and dietary strategies of prairie-nesting Ruddy Ducks and Redheads. Condor 91:280–287. Close , Kenow and Rusch 1996 Kenow, K. P. and D. H. Rusch. (1996). Food habits of Redheads at the Horicon Marsh, Wisconsin. Journal of Field Ornithology 67:649-659. Close ), of postbreeding birds on Manitoba lakes (Bailey and Titman 1984 Bailey, R. O. and R. D. Titman. (1984). Habitat use and feeding ecology of postbreeding Redheads. Journal of Wildlife Management 48:1144-1155. Close ), and of wintering birds in Texas and Louisiana (Mcmahan 1970 Mcmahan, C. A. (1970). Food habits of ducks wintering on Laguna Madre, Texas. Journal of Wildlife Management 34:946-949. Close , Cornelius 1977 Cornelius, S. E. (1977). Food and resource utilization by wintering Redheads on lower Laguna Madre. Journal of Wildlife Management 41:374-385. Close , Michot and Nault 1993 Michot, T. C. and A. J. Nault. (1993). Diet differences in Redheads from nearshore and offshore zones in Louisiana. Journal of Wildlife Management 57:238-244. Close , Mitchell et al. 1994 Mitchell, C. A., T. W. Custer and P. J. Zwank. (1994). Herbivory on shoalgrass by wintering Redheads in Texas. Journal of Wildlife Management 58:131-141. Close , Woodin 1996 Woodin, M. C. (1996). Wintering ecology of Redheads (Aythya americana) in the western Gulf of Mexico region. Gibier Faune Sauvage Game Wildl. 13:653-665. Close ).