Mallard (Anas platyrhynchos)

Mallard by Jack BartholmaiMallard distribution map


Population Information

The Federal BBS information can be obtained at by clicking on Trend Estimates and selecting the species in question. All estimates are for time period (1966-2005).

Life History

Habitat Selection

Mallards use a wide variety of habitats for feeding and nesting but ideal habitat conditions consist of diverse wetland complexes and upland cover in contiguity (Kaminksi and Weller 1992). Ephemeral, seasonal, and semipermanent wetlands and ponds are important for breeding pairs and broods. Mallards generally nest in areas with tall, dense vegetation (Evrard 2002) often within 150 meters of water (Drilling et al. 2002). In Wisconsin, residual switchgrass and bromegrass constituted the dominant vegetation around the nest site (Evrard 2002). Nests have been documented in a variety of locations, including idle grasslands, croplands, marshes, pastures, and roadside ditches (Drilling et al. 2002) as well as natural and constructed islands and artificial structures in wetland basins (Kaminski and Weller 1992, Chouinard et al. 2005), which may provide more protection from predators and thus higher nest success (Kaminski and Weller 1992). Urban Mallard also nest in less traditional substrates, including lawns, lakeshore developments, flat roofs (J. March, pers. comm.), ornamental shrubs, gardens, and woodpiles (Drilling et al. 2002). Emery et al. (2005) also found that managed cover types within the Prairie Pothole Region, such as planted cover and hayfields with delayed harvest, provided high early-season nesting success.

Mallards opportunistically respond to available habitat during migration and winter. Small ponds, marshes, streams, rivers, flooded fields, and reservoirs may be used during spring and fall migration. Urban ponds, exposed riverine areas, and other areas of open water close to a steady food source will provide refuge in the winter (Drilling et al. 2002). Mallards are able to withstand cold temperatures (Drilling et al. 2002) and remain in relatively large concentrations in southern Wisconsin during the winter (Robbins 1991).

Habitat Availability

Mallard is the most common nesting duck of Wisconsin and is found in a diversity of natural and urban settings. As a result of this habitat plasticity, Mallards are widespread throughout the state in all seasons (Robbins 1991). Nevertheless, continued wetland loss in Wisconsin is a concern for the state population. Prior to Euro-American settlement, wetlands occupied an estimated four million hectares of the total fourteen million hectares of Wisconsin’s land area. Today, 2.1 million hectares (53%) of these wetland habitats remain (WDNR 1995). Additionally, the amount and quality of undisturbed upland habitat in Wisconsin is limited. Intensive agriculture and urban development have caused major long-term losses in secure nesting cover (WDNR 1992). Early harvesting of these croplands may result in nest loss and hen mortality and have serious conservation implications (Petersen et al. 1982, WDNR 1992). Fortunately, efforts are underway to address these losses. The Conservation Reserve Program (CRP) and other set-aside acreages have increased upland cover in recent years (WDNR 1992) and provided secure nesting habitat. Additionally, the Upper Mississippi River/Great Lakes Region Joint Venture has protected, enhanced, or restored more than 51,000 hectares of upland habitat in Wisconsin as well as 37,000 hectares of wetland habitat. Strict wetland use regulations and incentive programs designed to restore or enhance wetlands also help to curb habitat loss and protect existing wetlands (WDNR 1995).

Population Concerns

Several long-term studies, including the Breeding Bird Survey, Waterfowl Breeding Population Survey for Wisconsin, and Wisconsin Checklist project, report an increasing population trend for Mallards (Rolley 2005, Sauer et al. 2005, Van Horn 2006). Mallards are a common winter resident in south and central Wisconsin, an abundant migrant, and a common summer resident throughout the state (Robbins 1991). During the Wisconsin Breeding Bird Atlas (1995-2000), observers confirmed Mallard as breeding in 57% of the surveyed quads (Martin and Martin 2006).
Large-scale alterations of wetlands and grasslands by agriculture, urbanization, and industrial activities impact populations. Mallards are the most harvested waterfowl species in North America and are thus the most studied and intensively monitored duck species. Annual breeding surveys, banding and research across North America assure that hunting regulations are adjusted annually to maintain a stable continental population (Drilling et al. 2002).

Recommended Management

Management efforts should focus on protecting remaining grasslands, particularly in those areas where numerous wetlands exist. Managers should consider establishing idle grasslands adjacent to existing wetlands to provide nesting cover. The recommended patch size for a nesting area is 32-40 ha, preferably in a square-like configuration (Petersen et al. 1982). However, landscape-level programs such as CRP may be more meaningful than actions that focus only on increasing nesting habitat patch size (Reynolds et al. 2001). Maintenance of optimal nesting habitat may require active management, e.g., allowing dead vegetation to accumulate and periodic burning, grazing, or mowing to prevent it from becoming too dense. However, managers are advised to conduct management activities during the non-breeding season to minimize disturbance on nesting birds (Sample and Mossman 1997).

Collaborative efforts to implement the habitat protection, restoration, and acquisition recommendations identified in the North American Waterfowl Management Plan will benefit Mallards and other wetland-associated species. In Wisconsin, managers should consider the following criteria for future acquisitions: (1) the presence of >16 ha of uplands capable of dense nesting cover; (2) at least 40 pairs of dabbling ducks within 0.8 km of the tract; (3) available brood habitat within 0.8 km of the tract; and (4) a minimum ratio of 1:4 brood water to upland nesting cover, or at least 4 ha of secure brood habitat within 0.8 km of the proposed tract (Petersen et al. 1982). Furthermore, wetland drawdowns that encourage growth of mudflat annuals, regenerate stands of emergent vegetation, stimulate primary productivity, and in turn improve the detrital base also should benefit Mallards (Kenow and Rusch 1996).

Research Needs

The effects of landscape factors on demographics and recruitment warrant further study. More research is needed to identify source and sink habitats and factors influencing the suitability of brood ponds. Long-term studies also are needed to determine lifetime reproductive success and factors influencing recruitment (Drilling et al. 2002).

Information Sources


Contact Information

Kreitinger, K., Y. Steele and A. Paulios, editors. 2013.
The Wisconsin All-bird Conservation Plan, Version 2.0. Wisconsin Bird Conservation Initiative.
Wisconsin Department of Natural Resources. Madison, WI.

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