Canvasback Aythya valisineria Scientific name definitions

This exclusively North American species is considered the “aristocrat of ducks.” The male's striking appearance—rich chestnut-red head and neck, black chest, white back, and long, sloping, blackish bill—along with its large size distinguish it in the field. The Canvasback's center of breeding is in the prairie-parklands of southern Canada, with major concentrations in winter along the Atlantic Coast (Chesapeake Bay and Pamlico Sound, North Carolina), Mississippi River delta and delta lakes in southern Louisiana, and San Francisco and San Pablo Bays, California. The species takes its specific name, Aythya valisineria, from Vallisneria americana, or wild celery, whose winter buds and rhizomes are its preferred food during the nonbreeding period. This is an omnivorous duck but specialized in its trophic requirements, preferring winter buds, tubers, rhizomes, and root stalks of submergent plants, as well as benthic invertebrates. Although often found in shallow water, the Canvasback is an adroit diver, diving to depths of more than 9 meters.

Gregarious and highly visible during the nonbreeding season, the Canvasback is monogamous and secretive during the breeding season. Pairs form during spring migration and continue to do so until they reach the breeding grounds. The breeding home range is large for this species, encompassing several ponds that pairs use for nesting, feeding, loafing, and brooding. The Canvasback nests over water, in a large structure constructed of loosely woven reeds and sedges and lined with down. This species is an ecological specialist whose restricted nesting and specific trophic requirements link it inextricably to deeper, more stable ponds, marshes, and potholes. During periods of severe drought, it responds promptly by delaying breeding or failing to breed at all, accounting in part for its small population size; this is one of the least abundant species of ducks in North America. The Canvasback is a primary host for parasitic egg-laying by the Redhead (A. americana), and brood parasitism is an important factor affecting its nesting success.

Since the 1960s, Canvasbacks have altered their traditional migration routes, changed wintering sites, and modified diets in response to changes in the availability and predictability of certain foods, changes generally attributed to declining abundance of plant tubers. Today, the species migrates along 3 principal corridors, with yearly local abundance varying considerably, depending on availability of food, weather conditions, disturbances, and hunting pressures. As a result of extensive molt-migration of males, sexes and age classes segregate during fall migration, causing highly disparate sex ratios at staging, stopover, and wintering areas; mixing of males and females during the nonbreeding season occurs primarily on the wintering grounds and spring migration.

The Canvasback is one of the most studied species of duck in North America. Excellent long-term studies of breeding populations at Minnedosa, Manitoba, have given us a unique synthesis of the overall biology of the species. Studies on the breeding grounds have contributed to our understanding of pair-bond and social behavior during the breeding cycle (Anderson Anderson 1984 Anderson, M. G. (1984). Parental investment and pair-bond behavior among Canvasback ducks (Aythya valisineria, Anatidae). Behavioral Ecology and Sociobiology 15:81-90. Close , Anderson 1985a Anderson, M. G. (1985a). Social behavior of breeding Canvasbacks (Aythya valisineria): male and female strategies of reproduction. Phd Thesis, Univ. of Minnesota, Minneapolis. Close ); factors affecting reproductive success (Stoudt 1982 Stoudt, J. H. (1982). Habitat use and productivity of Canvasbacks in southwestern Manitoba, 1961-1972. U.S. Fish Wildl. Serv. Spec. Sci. Rep. Wildl. Close , Barzen and Serie 1990 Barzen, J. B. and J. R. Serie. (1990). Nutrient reserve dynamics of breeding Canvasbacks. Auk 107:75-85. Close , Serie et al. 1992 Serie, J. R., D. L. Trauger and J. E. Austin. (1992). Influence of age and selected environmental factors on reproductive performance of Canvasbacks. Journal of Wildlife Management 56:546-556. Close , Arnold et al. 1995 Arnold, T. W., M. G. Anderson, R. B. Emery, M. D. Sorenson and C. N. De Sobrino. (1995). The effects of late-incubation body mass on reproductive success and survival of Canvasbacks and Redheads. Condor 97:953-962. Close , Anderson et al. 1997b Anderson, M. G., R. B. Emery and T. W. Arnold. (1997b). Reproductive success and female survival affect local population density of Canvasbacks. Journal of Wildlife Management 61:1174-1191. Close ); probability of recruitment of juvenile females into the breeding population (Anderson et al. Anderson et al. 1997b Anderson, M. G., R. B. Emery and T. W. Arnold. (1997b). Reproductive success and female survival affect local population density of Canvasbacks. Journal of Wildlife Management 61:1174-1191. Close , Anderson et al. 2001 Anderson, M. G., M. S. Lindberg and R. B. Emery. (2001). Probability of survival and breeding for juvenile female Canvasbacks. Journal of Wildlife Management 65:403-415. Close ); habitat use, survival, and movements of ducklings (Austin and Serie Austin and Serie 1991 Austin, J. E. and J. R. Serie. (1991). Variation in body mass of wild Canvasback and Redhead ducklings. Condor 96:909-915. Close , Austin and Serie 1991 Austin, J. E. and J. R. Serie. (1991). Variation in body mass of wild Canvasback and Redhead ducklings. Condor 96:909-915. Close ; Leonard et al. 1996 Leonard, J. P., M. G. Anderson, H. H. Prince and R. B. Emery. (1996). Survival and movements of Canvasback ducklings. Journal of Wildlife Management 60:863-874. Close ); and the behavioral response of Canvasbacks to brood parasitism by Redheads (Sorenson Sorenson 1993 Sorenson, M. D. (1993). Parasitic egg laying in Canvasbacks: frequency, success, and individual behavior. Auk 110:57-69. Close , Sorenson 1997 Sorenson, M. D. (1997). Effects of intra- and interspecific brood parasitism on a precocial host, the Canvasback, Aythya valisineria. Behavioral Ecology 8:153-161. 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 ). Studies at staging areas, at migratory-stopover sites, and on the wintering grounds have clarified timing and routes of migration (Serie et al. 1983 Serie, J. R., D. L. Trauger and D. E. Sharp. (1983). Migration and winter distributions of Canvasbacks staging on the upper Mississippi River. Journal of Wildlife Management 47:741-753. Close , Reinecker Reinecker 1985a Reinecker, W. C. (1985a). An analysis of Canvasbacks banded in California. Calif. Dep. Fish Game Bull. 71:141-149. Close ), food habits (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 ; Perry and Uhler 1988 Perry, M. C. and F. M. Uhler. (1988). Food habits and distribution of wintering Canvasbacks, Aythya valisineria, on Chesapeake Bay. Estuaries 11:57-67. Close ; Serie and Sharp 1989 Serie, J. R. and D. E. Sharp. (1989). Body weight and composition dynamics of fall migrating Canvasbacks. Journal of Wildlife Management 53:431-441. Close ; Austin et al. 1990 Austin, J. E., J. R. Serie and J. N. Noyes. (1990). Diet of Canvasbacks during breeding. Prairie Naturalist 22:171-176. Close ; Hohman et al. 1990b Hohman, W. L., D. W. Woolington and J. H. Devries. (1990b). Food habits of wintering Canvasbacks in Louisiana. Canadian Journal of Zoology 68:2605-2609. Close ; Jorde et al. 1995 Jorde, D. G., G. M. Haramis, C. M. Bunck and G. W. Pendleton. (1995). Effects of diet on rate of body-mass gain by wintering Canvasbacks. Journal of Wildlife Management 59:31-39. Close ; Thompson and Drobney Thompson and Drobney 1996 Thompson, J. E. and R. D. Drobney. (1996). Nutritional implications of molt in male Canvasbacks: variation in nutrient reserves and digestive tract morphology. Condor 98:512-526. Close , Thompson and Drobney 1997 Thompson, J. E. and R. D. Drobney. (1997). Diet and nutrition of male Canvasbacks during postreproductive molts. Journal of Wildlife Management 61:426-434. Close ; Haramis et al. 2001 Haramis, G. M., D. G. Jorde, S. A. Macko and J. L. Walker. (2001). Stable-isotope analysis of Canvasback winter diet in upper Chesapeake Bay. Auk 118:1008-1017. Close ), factors affecting winter and annual survival (Haramis et al. Haramis et al. 1986 Haramis, G. M., J. D. Nichols, K. H. Pollock and J. E. Hines. (1986). The relationship between body mass and survival of wintering Canvasbacks. Auk 103:506-514. Close , Haramis et al. 1993 Haramis, G. M., D. G. Jorde and C. M. Bunck. (1993). Survival of hatching-year female Canvasbacks wintering on Chesapeake Bay. Journal of Wildlife Management 57:763-771. Close ; Hohman 1993b Hohman, W. L. (1993b). Body composition of wintering Canvasbacks in Louisiana: dominance and survival implications. Condor 95:377-387. Close ; Hohman et al. Hohman et al. 1993 Hohman, W. L., R. D. Pritchert, J. L. Moore and D. O. Schaeffer. (1993). Survival of female Canvasbacks wintering in coastal Louisiana. Journal of Wildlife Management 57:758-762. Close , Hohman et al. 1995b Hohman, W. L., J. L. Moore and J. C. Franson. (1995b). Winter survival of immature Canvasbacks in inland Louisiana. Journal of Wildlife Management 59:384-392. Close ; Lovvorn and Jones 1994 Lovvorn, J. R., and D. R. Jones (1994). Biomechanical conflicts between adaptations for diving and aerial flight in estuarine birds. Estuaries 17:62-75. Close ), social behavior (Alexander 1987 Alexander, W. C. (1987). Aggressive behavior of wintering diving ducks (Aythyini). Wilson Bulletin 99:38-49. Close ; Takekawa 1987 Takekawa, J. Y. (1987). Energetics of Canvasbacks staging on an upper Mississippi River pool during migration. Phd Thesis, Iowa State Univ. Ame, Iowa State Univ. Ames. Close ; Lovvorn Lovvorn 1989b Lovvorn, J. R. (1989b). Food defendability and antipredator tactics: implications for dominance and pairing in Canvasbacks. Condor 91:826-836. Close , Lovvorn 1990 Lovvorn, J. R. (1990). Courtship and aggression in Canvasbacks: influence of sex and pair-bonding. Condor 92:369-378. Close ; Hohman and Rave 1990 Hohman, W. L. and D. P. Rave. (1990). Diurnal time-activity budgets of wintering Canvasbacks in Louisiana. Wilson Bulletin 102:645-654. Close ; Howerter 1990 Howerter, D. W. (1990). Movements and bioenergetics of Canvasbacks wintering in the upper Chesapeake Bay. Master's Thesis, Virginia Polytech. Inst. State Univ., Blacksburg. Close ; Thompson 1992b Thompson, J. E. (1992b). The nutritional ecology of molting male Canvasbacks (Aythya valisineria) in central Alberta. Master's Thesis, Univ. of Missouri-Columbi, Univ. of Missouri-Columbia. Close ; Bielefeld 1993 Bielefeld, R. R. (1993). Habitat-related variation in Canvasback behavior and food density on the Mississippi River Delta, Louisiana. Master's Thesis, Louisiana State Univ., Baton Rouge. Close ), and foraging ecology (Takekawa 1987 Takekawa, J. Y. (1987). Energetics of Canvasbacks staging on an upper Mississippi River pool during migration. Phd Thesis, Iowa State Univ. Ame, Iowa State Univ. Ames. Close , Tome and Wrubleski 1988 Tome, M. W. and D. A. Wrubleski (1988). Underwater foraging behavior of Canvasbacks, Lesser Scaups, and Ruddy Ducks. Condor 90:168–172. Close , Lovvorn and Jones 1991b Lovvorn, J. R. and D. R. Jones. (1991b). Effects of body size, body fat, and change in pressure with depth on buoyancy and costs of diving in ducks (Aythya spp.). Canadian Journal of Zoology 69:2879-2887. Close , Lovvorn et al. 1991 Lovvorn, J. R., D. R. Jones and R. W. Blake. (1991). Mechanics of underwater locomotion in diving ducks: drag, buoyancy and acceleration in a size gradient of species. Journal of Experimental Biology 159:89-108. Close , Ball 1994 Ball, J. P. (1994). Prey choice of omnivorous Canvasbacks: imperfectly optimal ducks? Oikos 70:233-244. Close ).