The Mallard (Anas platyrhynchos), recognizable by the male’s iridescent green head, is the most common and widespread duck species in the Northern Hemisphere. This highly adaptable species thrives in wetlands, parks, and urban environments across vast geographical ranges. Tracking the Mallard population provides wildlife managers with data for annual conservation and hunting regulations. The Mallard serves as a baseline indicator for the health of North America’s entire waterfowl community.
Current Global and Regional Estimates
A definitive global population number for the Mallard is unavailable due to its extensive distribution across Eurasia, North Africa, and the Americas. The most precise and consistently tracked figures come from the annual North American Waterfowl Breeding Population and Habitat Survey (WBPHS). This survey focuses on the primary breeding grounds in the traditional survey area (TSA), which includes parts of Alaska, Canada, and the northcentral United States.
The 2025 breeding population estimate for Mallards in the TSA was approximately 6.55 million birds. This figure represents a 17% decrease compared to the long-term average calculated since 1955.
The Eastern Survey Area, covering the Atlantic Flyway breeding grounds, estimated the population at 1.14 million birds in 2025. This eastern stock was 9% below its own long-term average. Combining these figures yields a total North American breeding population index of around 7.69 million Mallards.
Methods for Counting Waterfowl Populations
Specialized survey techniques are used to estimate Mallard populations accurately. The primary method across the North American prairies is the aerial survey, conducted annually by the U.S. Fish and Wildlife Service and the Canadian Wildlife Service. Observers fly in aircraft at low altitudes, following established transect lines.
During these flights, observers count “indicated pairs,” often determined by counting visible male ducks (drakes). The number of unpaired males is doubled to account for less conspicuous females (hens) sitting on nests. Aerial counts are supplemented by ground-based surveys to verify data accuracy and account for visibility bias.
Scientists also utilize extensive banding programs to gather demographic data. Hundreds of thousands of leg bands are placed on birds annually, allowing researchers to track migration patterns, survival rates, and harvest mortality through recovery reports. This comprehensive approach provides the scientific basis for waterfowl management.
Geographical Range and Density Variations
The Mallard has a native range that spans the temperate and subtropical regions of North America, Eurasia, and North Africa. It has also been introduced to other areas, including Australia and New Zealand. This wide distribution means that population density varies significantly depending on local habitat conditions.
The highest densities of breeding Mallards in North America are found in the Prairie Pothole Region, an area of the Great Plains characterized by millions of small, glacially formed wetlands. In this region, breeding density is highly correlated with the temporary abundance of water, with numbers increasing dramatically during wet years. Density is much lower in vast, forested areas like the boreal forest or in the sparse wetlands of the western United States.
Migration dramatically shifts the population distribution throughout the year. Northern breeding populations travel thousands of miles south along four major North American flyways—the Atlantic, Mississippi, Central, and Pacific—to reach warmer wintering grounds. This seasonal movement requires distinct surveys for breeding populations in the spring and for wintering populations in the fall and winter.
Key Drivers of Mallard Population Health
The health of the Mallard population depends on the availability and quality of its breeding habitat. Wetland conditions, particularly the number of temporary ponds present in May, are a primary predictor of breeding success in the Prairie Pothole Region. When drought reduces the number of these “May ponds,” fewer hens attempt to nest, and overall production drops.
Predation is another major ecological factor limiting population growth, especially the rate of nest success. Ground-nesting Mallards suffer significant losses, primarily from mammalian predators like skunks, raccoons, and foxes. In altered landscapes, nest success rates are often below the 15-20% threshold necessary to maintain a stable population.
Human intervention also affects population dynamics through management and unintended genetic influence. Hunting regulations, adjusted annually based on survey data, directly affect the harvest rate and survival. Additionally, introducing non-wild Mallards from game farms can dilute the genetics of wild populations, potentially impacting migration behavior and survival rates.