Mallards on the move

Even though mallards are common and easy to find, not all of them are thriving. While mid-continent mallards are doing relatively well, eastern mallards are in decline, with the Atlantic Flyway Migration Project noting that mallards in the Atlantic Flyway have faced a population decline of approximately one per cent annually since 1998. “So we’re trying to figure out what’s going on with the overall decline,” says Waldrep.

Waldrep’s work dives into behavioural ecology — how mallard choices and environments affect their ability to reproduce and survive. She’s comparing the reproductive success of birds in eastern Canada (a stable subpopulation) with those in the northeastern United States (a declining subpopulation) and considering how factors such as age and habitat use during the breeding period might explain reproductive success. She also is examining potential competition with black ducks (a species co-occurring with mallards in eastern North America).

Huss, meanwhile, is examining how different tracking device attachment techniques may affect the movement, behaviour, survival and reproductive success of mid-continent mallards.

“Essentially, what I’m doing is quantifying how these different attachment techniques can lead to differences in the data we’re collecting from the birds… and how we can use this information to help guide future research,” says Huss.

A tale of two flyways

So, what separates eastern mallards from their mid-continent cousins? Geography, mostly. While eastern mallards breed in Ontario, Quebec, the Maritimes and northeastern U.S., and migrate down the Atlantic Flyway to winter in the eastern United States, mid-continent mallards largely stick to the Mississippi and Central Flyways, breed in prairie wetlands and winter in the southern United States.

Eastern mallards also differ slightly genetically, Waldrep points out. This is partly due to game bird releases — where domesticated mallards are raised and released for sport shooting.

“So then you’re introducing domestic genes into the population and that potentially results in differences in their behaviour compared to that of more wild-type mallards, which is why there are hypotheses about the extent to which genetics might explain the eastern mallard decline.”

And then there’s the mystery of “resident” mallards —birds that don’t migrate at all. “On the East Coast, about 30 per cent of our tagged hen mallards are resident birds,” says Waldrep. “It raises the question of why some birds invest energy in migration, whereas some are relatively stationary year-round?”

Following the flock

Waldrep and Huss hope the data collected from various tracking devices will help explain the mallards’ predicament. These include 20-gram solar-powered backpack units, which are placed on the birds’ backs; tiny geo-locators, or light sensors, attached to leg bands; and implants. Data are uploaded via cellular networks and researchers can log onto a website to see where tracked birds are and what they’re doing, “assuming it’s in an area that has cellular service,” notes Huss.

While research is ongoing and early results are trickling in, some fascinating patterns are emerging. For instance, while current hypotheses suggest urbanization has an adverse effect on reproductive success, “our preliminary results show that urban landscapes can be suitable for mallard broods,” says Waldrep.

Weather might also play a role in declining populations, she adds, especially on the Atlantic coast, where long cold snaps can prove deadly for birds.

One thing that researchers are learning is the extent to which habitat matters. Mid-continent mallards, says Huss, rely heavily on wetlands for reproduction. Wetlands provide invertebrate food for hens and their ducklings, as well as protection from predators.

“But it’s not just habitat,” says Waldrep. “It’s where the habitat is and what’s around it. You can’t just put a wetland in the middle of unusable space and hope a duck is going to use it… we want to really target wetland conservation in a manner that maximizes survival and reproduction.”

Waldrep further notes that while some consider mallards a “basic duck,” they’re extremely important in the hunting community. “And people are worried about this decline.”

Harvesting data: How hunters can help

As the saying goes, many hands make light work, and the volunteers who help during waterfowl banding season are vital, assisting with tasks like recording data or holding birds while they’re being banded.

Hunters, Waldrep says, also play a key role in ongoing research. “Sometimes the devices stop working, or the bird dies in an area without cellphone coverage, and we’ll never know what happened to it,” she explains. That’s why, if you harvest a duck with a transmitter or geo-locator, reporting it using the email or phone number provided on the unit is crucial.

“If they don’t reach out to us let us know they have it, we’ll never see those data,” Huss adds, noting that the geo-locators are the only data collectors they use where they must recover the unit to get the information. “Co-ordinating how to get the geo-locator back so I can download the data and then ship the unit right back to them [the finder] is really pivotal, especially for my research.”

Hunters also help by retrieving the transmitters when researchers can’t reach a particular location. Returning these costly devices is more than good science — it’s good economics. “If we can get it back and put it on another bird, we’re saving literally thousands of dollars,” says Waldrep.

Hunters who return the units often get a map of their duck’s movements and other information about the bird, a hat, or even a replica transmitter to display. But most importantly, Waldrep says, is the sense of pride that comes with knowing your actions have contributed to critical research and conservation efforts. “We will have hundreds of hunters in North America that directly impacted the data that’s coming from this project… so it really excites people.”

Mallards are more than just a familiar face in the marsh, they’re also a keystone species and important for biodiversity, supporting everything from bald eagles to bass.

“When one population is declining, even though you might not see it, that’s going to impact another population… these ecosystems have such intricate interactions that as conservationists, we want to keep those as stable as possible,” says Waldrep.

“So not only are you conserving your game duck, but you’re also conserving nature for you, your family and future generations to enjoy. And I don’t think there’s more joy than that.”

A continental collaboration

The Atlantic Flyway Migration Project relies on the collaboration of dozens of state and Canadian/American federal employees including migratory waterfowl specialists, wildlife biologists and technicians. The leadership team for Waldrep’s project includes Josh Stiller (New York State Department of Environmental Conservation), John Coluccy (Ducks Unlimited, Inc.), Jake Straub (State University of New York-Brockport) and Mitch Weegman, while the leadership team for Huss includes Matt Dyson (DUC), Chris Nicolai (Delta Waterfowl Foundation), Paul Link (Louisiana Department of Wildlife and Fisheries), Karen Machin (University of Saskatchewan) and Mitch Weegman.

For more information about the eastern mallard project as well as a complete list of collaborators and funders, visit Atlantic Flyway Migration Project.

Survey says: Mallard decline signals broader habitat loss

The annual Waterfowl Population Status Report released in early September indicated that populations of mallards — a flagship species for wetland conservation and restoration efforts — are at least 10 per cent below the long-term average in both the traditional survey area and eastern survey area, drawing attention to drivers of population change for populations east of the Rockies, including the mid-continent, Great Lakes and eastern breeding areas.

The common denominator for these breeding subpopulations is the importance of breeding habitat conditions on productivity, although the threats and solutions for habitat may vary by region. This is why DUC is investing in research by Waldrep and Huss to understand what drives these populations and how our conservation programs can offer solutions to help sustain mallard productivity.

Learn more about these and other research projects tackling some of the greatest conservation challenges.