On the Trail of the Pintail
A new continent-wide research project is using cutting-edge technology to track the migrations of these magnificent birds
By Chris Madson
Among North America's waterfowl, few if any can match the grace and beauty of the northern pintail. Sadly, populations of these highly admired birds have remained persistently depressed, while many other species of ducks have recovered to healthy levels.
At one time, pintails were far more numerous than they are today. In 1956, the annual survey of duck populations in North America estimated that there were 10.4 million breeding pintails on the continent's prairie potholes, parklands, and Boreal Forest, rivaling the ubiquitous mallard in abundance in the three western waterfowl flyways. Over the next decade, intermittent drought in southern Canada put a dent in populations of pintails and other prairie-nesting ducks. By 1965, estimates of breeding mallards had dropped by more than half, and pintail numbers had fallen by 65 percent.
Any veteran observer of waterfowl populations will tell you that duck numbers are as volatile as the prairie weather, and the surveys certainly bear that out. Since 1965, mallard and pintail populations have been as low as 4.9 million and 1.8 million birds, respectively. But following the end of the most recent severe prairie drought, in the mid-1990s, mallards and many other prairie ducks have shown a sustained recovery. Numbers of breeding mallards have bounced between 9 million and 12 million birds over the past decade, and gadwalls, blue-winged teal, and shovelers have approached record highs.
But over that same 10-year span, the average number of breeding pintails has flatlined. "In years that we've had really good wetland conditions, pintails have been one of the few species that hasn't shown a good response," says Dr. Dale James, director of conservation planning in Ducks Unlimited's Southern Region. "Their populations are about 40 percent below the long-term average. The North American Waterfowl Management Plan goal for the species is about 4 million birds. Right now, we're estimating there are a little over 2 million."
Farming practices on the Canadian prairies are thought to be the primary factor that has prevented pintail populations from recovering. Pintails nest in relatively open habitats compared to other prairie-nesting ducks, often in fallow agricultural fields. Recent changes in the timing of when those fields are plowed have had a direct impact on pintail nesting success. Because other species prefer to nest in grassland habitats, this change in farming practices has not impacted their populations.
To help pintails and other prairie-nesting ducks, DU is working with farmers and other agricultural partners to increase the acreage of winter wheat planted in the Prairie Pothole Region. Unlike spring-seeded crops, winter wheat is planted in the fall and remains undisturbed throughout the spring nesting period, giving nesting pintails a much better chance of hatching broods. In addition, DU continues to make progress in protecting and restoring prairie grasslands and wetlands through direct acquisition and conservation easements, benefiting breeding pintails and a variety of other waterfowl.
While habitat loss and changing agricultural practices on the breeding grounds have played a large role in the decline of pintail populations, ongoing changes to wintering and migration habitats may now be equally important. Not surprisingly, the availability of food in winter and during migration has the potential to affect the fortunes of waterfowl. Vital nutrients acquired while feeding in wetlands and agricultural lands not only bolster winter survival, but also prepare the birds for the spring migration and the energetic demands of breeding. Females in poor condition may be delayed during migration, initiate nests later, invest less effort in nesting, or forgo breeding altogether.
James explains that during the nonbreeding period the challenges facing pintails in the heartland of the Mississippi and Central Flyways are unlike those in California. "We've got all these different groups of pintails that use different wintering areas and other nonbreeding habitats," he says. "Their survival rates and body condition also vary considerably in different parts of their range. We're trying to figure out why. If we can understand their movements, habitat use, and other behaviors, then we can tease out why pintails in some areas are faring better than others. And that would help us determine how best to conserve habitats in key areas to help pintails."
To better understand pintail ecology and plan for their management, Ducks Unlimited has partnered in a research effort led by Dr. Bart Ballard with the Caesar Kleberg Wildlife Research Institute at Texas A&M− Kingsville. It is well known that movements and feeding behaviors of waterfowl in nonbreeding areas are driven by the birds' energy needs. "Pintails spend a long time on nonbreeding areas compared to many other ducks," Ballard says. "Because they arrive early on the breeding grounds in spring, and initiate nesting early, they tend to rely more on stored reserves from nonbreeding areas to sustain some of their breeding activities, including egg production and incubation. Thus, management activities on nonbreeding areas may be especially important to pintails and play a key role in their population recovery."
When he considers the stark differences in habitat conditions pintails encounter while migrating between breeding and wintering areas in each of the flyways, Ballard is convinced that the birds have distinct migration strategies and behaviors in these regions. "Pintails are likely using different strategies to optimize time and energy during migration because they have different opportunities to stop over," Ballard says. "After leaving the wintering grounds, Pacific Flyway pintails have fewer options on where they can stop to rest and refuel than midcontinent birds." He hypothesizes that pintails that winter along the Gulf Coast "may not have to leave as heavy" as Pacific Flyway birds when they start north in the spring.
To understand the consequences of these different strategies, researchers have to follow the birds during their epic transcontinental migrations. Once upon a time, that meant banding massive numbers of birds. Then, in the 1950s, the same transistors that allowed teenagers to carry radios in their pockets allowed technicians to build transmitters that were small enough to attach to wildlife, eventually even ducks and geese. During the early years of this technology, however, researchers had to follow the birds with radio telemetry equipment to track the birds' movements. Now these tracking devices are solar powered and link to global positioning satellites, allowing researchers to gather a wealth of data on individual birds for a year or more without ever leaving the office.
"The transmitters are becoming smaller and lighter," Ballard says. "We can now put them on birds that we weren't able to track in the past. We're getting a lot more data and we're getting it more frequently."
In this brave new world of technology, researchers can log on to a website with a laptop, locate a pintail with a precision of less than 20 feet, pinpoint its location on a landcover map to see what type of habitat it is in, and figure out what that bird is doing—nearly in real time.
In addition to tracking location, the transmitters are equipped with accelerometers, which measure differences in the birds' activity levels. "We get data that allows us to differentiate major behaviors of the birds, such as flying, feeding, preening, or standing," Ballard says. "For the pintail study, identifying foraging behavior is key to helping us answer some of our questions."
With funding from Ducks Unlimited, Texas Parks and Wildlife Department, and the US Fish and Wildlife Service and assistance from New Mexico Department of Game and Fish, Louisiana Department of Wildlife and Fisheries, and US Geological Survey, Ballard and his colleagues are using this new technology to probe the mysteries of pintail migrations, including the locations of preferred spring staging areas and how the birds fuel their travels along the flyways. The fieldwork and data analysis for this ambitious study fall to Georgina Eccles, a doctoral student at the Kleberg Institute. She's eager to apply her background of research on animal behavior and conservation in the United Kingdom to the problems pintails face in North America.
"The Gulf Coast has been known to hold about 78 percent of pintails that winter in the Central Flyway," Eccles explains. "They rely on carbohydrate-rich food resources, predominantly rice along the Texas Coast. These rice prairie landscapes are being lost because of changes in agriculture and urban sprawl. Pintails are having to respond to these landscape changes by moving into other habitats, often of lower quality."
The situation in the Pacific Flyway is only marginally better. "Wetland habitats are being lost in many areas of the West because of urbanization," Eccles adds. "Agricultural changes are affecting the landscape. The wetland loss California has experienced, in particular, is drastic and very concerning."
Last winter Ballard, Eccles, and their colleagues trapped 140 pintails on wintering areas including the Texas and Louisiana Gulf Coast, Texas Panhandle, southwest Arizona, Central Valley of California, and the Middle Rio Grande Valley of New Mexico. Female pintails were fitted with radio transmitters weighing only a little more than a half-ounce each. These transmitters broadcast GPS locations and information on bird movements to nearby cell towers, which in turn deliver the data to computer servers. Eccles hopes to mark another 180 pintails with transmitters this winter.
"An important part of this project is to untangle the migration strategies within and across regions and find out whether certain strategies are more successful than others in terms of reproductive success," Eccles says. And those strategies may well be shaped by the availability of food resources on spring staging areas. "It's crucial," she continues, "for pintails to maintain nutrient reserves not only for reproduction but also for maintenance on these long-distance flights. Pintails might not be in optimum body condition to produce eggs when they reach the breeding grounds, so we're going to be looking at those migration strategies that result in successful reproduction. In particular, we plan to identify key stopover sites that contribute most to reproductive success so we can inform management decisions in order to have the greatest positive impact on the population."
The study reaches from the Laguna Madre of Texas to Alaska's Yukon Delta, with implications that could affect the future of one of the continent's best known, and most beloved, migratory birds. It's not surprising that information of that scope and importance doesn't come cheap. A single transmitter runs just shy of $1,300. Then there is the cost of other equipment, data access, manpower, travel, and more. That's where DU, its research partners, and all of us who admire these magnificent birds come in. We can pick up the tab for the pintail. We haven't adequately counted the cost of their conservation in the past, and I think most of us will be proud to pay the price to help secure their future.
Chris Madson trained in wildlife biology and spent 35 years with state wildlife agencies before pursuing a full-time career in freelance writing. He makes his home in Cheyenne, Wyoming.
Coypu Foundation Supports Mottled Duck Research
Retaining the dedication to conservation and ecological research embodied by founder John S. McIlhenny, the Coypu Foundation of New Orleans is a generous supporter of waterfowl research. The foundation recently provided support for important mottled duck research in Louisiana.
Mottled ducks are North America's only nonmigratory waterfowl species. More than 90 percent of their population occurs along the western Gulf Coast. The Louisiana mottled duck population has declined over the past decade, and in 2018 their numbers were the lowest on record. This decline appears to be tied to the high rate of coastal wetland loss and agricultural shifts from rice to other crops in south Louisiana.
Many questions remain about mottled duck breeding ecology and habitat use. To answer some of these questions, the Coypu Foundation, Ducks Unlimited, the Louisiana Department of Wildlife and Fisheries, Gulf Coast Joint Venture, and Louisiana State University are collaborating in a research study to better understand the breeding ecology of mottled ducks in the southwestern portion of the state. This four-year study is examining the factors that impact mottled duck nesting success, adult survival, and breeding propensity (likelihood that a female will breed). When completed in late 2020, results from this study will help direct conservation and habitat management programs to sustain and increase mottled duck numbers along the Gulf Coast.