Are Game Farm Mallards a Threat to Wild Populations?

Ask the locals on the other side of the river—there is nothing more beautiful than a greenhead descending into a timber hole at daybreak. Countless marriages have ended over the pursuit of this very image. I grew up drawn to the allure of wary black ducks, mysterious ghosts often barely seen in the mist of the Atlantic. But mallards are upfront, in your face and in your decoys. They are iconic; the Beatles of the duck world, well-known to both hunters and the general public alike. Open your iPhone, search the “emojis” and see. Go down to your local pond and take a look around. But while you are there—I need to ask—do any of the mallards look “odd” to you?

The prevalence and spread of game-farm mallard genes in the wild population is an emerging concern for researchers, and it is something hunters need to be aware of. Not only do they create some odd-looking ducks, but they also make the wild mallards we love something entirely different.

But how widespread is the issue, what are the concerns, and what does it all mean for the future of wild mallard populations?

The History and Spread of Game-Farm Mallards

In Europe, countries such as France, the United Kingdom, and Germany relied heavily on large-scale releases of game-farm mallards to sustain hunting opportunities beginning in the 20^th century. The impacts of these game farm genes were detrimental to the wild mallard populations. Currently, France alone releases nearly 3 million birds annually to maintain huntable populations, a practice now necessitated by decades of hybridization and declining wild populations.

In North America, game-farm mallard releases peaked in the mid-20th century. While exact figures vary, research indicates that millions of game-farm birds were released across the eastern United States from the 1920s through the 1960s to boost hunting opportunities. Although large-scale releases have lessened, continued releases provide a source of genes maintaining their genetic blueprint, most notably in the Atlantic Flyway and Great Lakes.

In 2019, Dr. Philip Lavretsky at the University of Texas at El Paso (UTEP) discovered “mystery genes” during his research into mallards and black ducks. These genes were later identified as those from game-farm mallards. The more they looked, the more these genes popped up, prompting additional investigations and the eventual launch of duckDNA—a partnership with Ducks Unlimited and the Lavretsky Lab at UTEP to understand the extent of the genetic signature in North American mallard populations.

Behavioral and Ecological Impacts

The extent of the spread and impact of these “hybrid swarms” is still not fully understood by scientists, but the research is quickly piling up. How these game-farm genes have contributed to regional wild mallard population declines, if at all, is a major question.

The recent study "Movement and population dynamics of Great Lakes mallards," out of Michigan State University, led by Dr. Benjamin Luukkonen, investigated the effect of hybridization between wild and game-farm mallards in the Great Lakes region. Supported by Ducks Unlimited and other partners, this research combined genetic data and GPS tracking of 592 hen mallards to assess behavioral and habitat selection differences between hybrids and pure wild mallards

The findings were significant. 44% of the hen mallards observed in the study were genetically wild, while 56% were game-farm hybrids or had game-farm ancestry. Those with higher game-farm ancestry exhibited shorter daily movements, reduced migration, and a preference for urban habitats, diverging from the wild population's traditional migratory behavior and use of rural wetlands. These observations raise concerns for the long-term conservation of wild mallard populations, as hybridization appears to affect ecological fitness and could contribute to the species' regional decline if the prevalence of game-farm genes increases throughout the population.

"This new data provides valuable insights that will not only help Ducks Unlimited, but also the larger waterfowl conservation community in sustaining declining wild mallard populations in the Great Lakes region," said Dr. John Coluccy, Director of Conservation Science and Planning for Ducks Unlimited's Great Lakes Atlantic Region.

The physiological traits of hybrids also differ from wild mallards in ways that can affect their ecological fitness. Lavretsky’s lab documented several notable changes, including shorter, broader bills with fewer lamellae—the structures that allow mallards to filter food from water. These physical differences reduce feeding efficiency, forcing hybrids to work harder to meet their nutritional needs.

According to Lavretsky, in controlled third-party feeding trials, hybrids with prevalent game-farm ancestry required nearly twice as much time to consume enough calories compared to their wild counterparts. These challenges are compounded during harsh winters when efficient feeding can mean the difference between survival and starvation. Other traits influenced by game-farm ancestry include longer legs, shorter wings, and even a reduction in fat storage capacity.

duckDNA: Decoding the Hybridization

Efforts to understand regional patterns and the overall scale of hybridization in the U.S. are being bolstered by an innovative collaboration between Ducks Unlimited and the Lavretsky Lab at UTEP. This project, known as duckDNA, now in its second year, enlists hunters to collect tissue samples from harvested ducks for genetic analysis. Hunters receive sampling kits to collect tissue from three harvested ducks and submit them for laboratory analysis. In return, participants receive a "Certificate of Pedigree" detailing each duck's genetic makeup.

While one of the objectives of duckDNA is to assess how widespread game-farm mallard hybridization is across the U.S., it is also building an unprecedented database of mallard genomes. Researchers believe that with time, these data will offer a deeper understanding of how genes influence mallard migration, habitat use, regional affiliations, disease susceptibility, productivity, and more.

"By contributing genetic samples, hunters are providing essential data that will help clarify the scale of the game-farm mallard issue while enabling additional studies that will push our knowledge of waterfowl populations to new levels," said Dr. Mike Brasher, Ducks Unlimited senior waterfowl scientist.

Check out some of duckDNA’s most interesting hybrids on their Instagram.

Charting a Path Forward

While researchers are making significant strides in understanding the effects of hybridization, there is still much to learn. Some of the most pressing questions include how far west game-farm genes have spread and how hybridization affects mallards' long-term survival, productivity, and adaptability. Although hybridization has regionally impacted the Atlantic Flyway and the mid-continent, preliminary evidence indicates that mallards in the western United States still remain largely wild and genetically “pure.”

Luukkonen’s preliminary research also suggests that birds with approximately 70–80% wild ancestry behave and perform similarly to fully wild mallards, indicating that nature can still overpower game-farm traits if a sufficiently large population of wild mallards exists.

“Our goal is to identify where that cutoff point is—how much domestic ancestry a bird can carry before it starts to lose the traits that make it a wild mallard,” Lavretsky said. “If we can pinpoint that, it could help provide a roadmap for restoring genetic integrity to populations.”

Future research also hopes to shed more light on how hybridization relates to population trends. Mallards in the Great Lakes and northeastern United States, where hybridization is most pronounced, have shown signs of decline in recent decades. Researchers are working to determine whether the influx of game-farm genes is contributing to these declines and, if so, to what degree.

Through ongoing research and collaborative efforts like duckDNA, hunters, scientists, and conservationists are working together to ensure the resilience of mallards for generations to come. By combining the traditions of waterfowl hunting with the latest advancements in genetic science, they are uncovering the intricate dynamics of hybridization and charting a path forward for one of North America’s most iconic species.