Status: Abundant regular spring and fall migrant statewide. Common regular breeder statewide. Common, locally abundant, regular winter visitor statewide.
Documentation: Specimen: UNSM ZM7674, 11 Apr 1916 Lancaster Co.
Taxonomy: No subspecies are currently recognized (Baldassare 2014).
McCracken et al (2001) found that there were two separate groups of mallard-type ducks that colonized North America. Colonization by a monochromatic ancestral mallard resulted in three monochromatic species (American Black Duck A. rubripes, Mexican Duck A. diazi, and Mottled Duck A. fulvigula). The familiar dichromatic Mallard developed in the other group, and subsequently colonized North America, where it was able to hybridize with the existing monochromatic mallard-type ducks. Avise et al (1990) discovered two haplotypes (sets of DNA variations that tend to be inherited together) in North American Mallards. It appears that the type B haplotype arises from hybridization with black ducks (including American Black, Mottled and Mexican), while pure Mallards are type A.
Although hybridization by American Black Duck with Mallard occurs, it was at one time thought not widespread enough to consider the two conspecific (Johnsgard 1975), but, more recently, hybridization has become extensive in certain parts of the American Black Duck range. A DNA study by Mank et al (2004) comparing American Black Duck and Mallard specimens collected before 1940 and in 1998 showed a “significant reduction in genetic differentiation’, and represented a “breakdown in species integrity most likely due to hybridization” (Mank et al 2004).
Spring: Mallards numbers increase by late-winter as water opens up, and numbers quickly rise to peak counts in early Mar. Some 50% of the mid-continent population uses the Rainwater Basin in spring (Gersib et al 1989).
- High counts: 200,000 at Harlan Co Reservoir, Harlan Co 9 Mar 2003, 81,000 in the eastern Rainwater Basin 17 Mar 2001, and 23,792 at North Platte NWR, Scotts Bluff Co 11 Mar 1997.
Summer: Mallards breed statewide in a variety of habitats, including traditional wetland-grassland mosaics but also in suburban and urban settings. The most important breeding areas in Nebraska are the Sandhills and the Rainwater Basin (Baldassare 2014). In the Rainwater Basin, it is the second most common nesting duck species behind only Blue-winged Teal; Evans and Wolfe (1967) found 18% of all duck nests (n = 206) during 1958-1962 to be this species. Harding (1986) found 16% of all duck nests (n= 723) during 1981-1985 to be of Mallard. Nests are usually on the ground, although a hen made a nest seven feet above the ground in a hollow stump in Sioux Co in 2002; there were seven eggs present on 7 Jul (Mollhoff 2004).
Mallard drakes leave nesting sites in May and Jun in molt migration, commonly at locations in Nebraska. A male was undergoing pre-alternate molt into “eclipse” plumage (Howell 2010) near North Platte, Lincoln Co 9 Jul 2007. Females join these flocks later, prior to primary fall migration (Palmer 1976).
- Breeding phenology:
Eggs: 12 May-27 Jul.
Dependent fledglings: 20 May-3 Sep.
Fall: Major movements are much more discernible in the fall than spring. Numbers begin to increase in the state in mid-Oct and achieve peak counts in late Nov through mid-Dec.
Bands taken by Nebraska hunters from fall and early winter kills indicate that the majority of individuals were produced in the prairie provinces of Canada.
- High counts: 150,000 at Harlan Co Reservoir 15 Dec 2000, 100,000 at Sutherland Reservoir, Lincoln Co 30 Dec 2011, 88,765 at North Platte NWR 28 Nov 1995, and 73,792 there 25 Nov 1997.
Winter: Winter concentrations are dependent on available open water and exposed grain in nearby fields and feedlots. Nebraska hosts some 17.5% of the North American wintering population (Baldassare 2014).
- High counts: 50,000-80,000 at Sutherland Reservoir 9 Jan 2011, 40,000 at Harlan Co Reservoir 6 Feb 2000, 34,000 at Swanson Reservoir, Hitchcock Co 3 Jan 2018, 15,000-20,000 at Sutherland Reservoir 6 Jan 2012, and 16,900 there 29 Dec 2016.
NWR: National Wildlife Refuge
UNSM: University of Nebraska State Museum
Photograph (top) of Mallards at Fontenelle Forest, Sarpy Co, 22 Apr 2009 by Phil Swanson.
Avise, J.C., C.D. Ankney, and W.S. Nelson. 1990. Mitochondrial gene trees and the evolutionary relationship of Mallard and Black Ducks. Evolution 44: 1109-1119.
Baldassarre, G. 2014. Ducks, geese, and swans of North America. Johns Hopkins University Press, Baltimore, Maryland, USA.
Evans, R.D., and C.W. Wolfe. 1967. Waterfowl production in the Rainwater Basin area of Nebraska. Journal of Wildlife Management 33: 788-794.
Gersib, R.A., B. Elder, K.F. Dinan, and T.H. Hupf. 1989. Waterfowl values by wetland type within Rainwater Basin wetlands with special emphasis on activity time budget and census data. Nebraska Game and Parks Commission, Lincoln, Nebraska, USA, and U.S. Fish and Wildlife Service, Grand Island, Nebraska, USA.
Harding, R.G. 1986. Waterfowl nesting preferences and productivity in the Rainwater Basin, Nebraska. Master’s thesis, Kearney State College, Kearney, Nebraska, USA.
Howell, S.N.G. 2010. Molt in North American Birds. Houghton Mifflin Harcourt, Boston, Massachusetts, USA.
Johnsgard, P.A. 1975. Waterfowl of North America. University of Indiana Press, Bloomington, Indiana, USA.
Mank, J.E., J.E. Carlson and M.C. Brittingham. 2004. A century of hybridization: Decreasing genetic distance between American black ducks and mallard. Conservation Genetics 5: 395-403.
McCracken, K.G., W.P. Johnson, and F.H. Sheldon. 2001. Molecular population genetics, phylogeography, and conservation biology of the mottled duck (Anas fulvigula). Conservation Genetics 2: 87-102.
Mollhoff, W.J. 2004. The 2001 Nesting Report. NBR 72: 99-103.
Palmer, R.S., ed. 1976. Handbook of North American birds. Vol. 2. Waterfowl (Parts 1 and 2). Yale University Press, New Haven, Connecticut, USA.
Silcock, W.R., and J.G. Jorgensen. 2018. Mallard (Anas platyrhynchos), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org
Birds of Nebraska – Online