In southwestern Montana’s Centennial Valley, the dawn fog filled with avian cacophony: the persistent rudder of duck wings, the woody creak of white-faced ibis in flight and the constant chatter of marsh wrens. At Lower Red Rock Lake, a crew of 11 University of Montana researchers and Ducks Unlimited volunteers launched canoes onto the waking wetlands with practiced ease. It was a mid-August morning, and the Lesser Scaup Project was setting out for its 22nd consecutive year of duck banding, adding one more season to one of the world’s longest-running and highest-resolution datasets on breeding ducks.
Home to the largest wetland complex in the Greater Yellowstone Ecosystem, the Red Rock Lakes National Wildlife Refuge provides habitat for thousands of migratory birds. While the refuge was created in 1935 to protect trumpeter swans, the quiet and enduring conservation story of the Centennial Valley is that of the lesser scaup, a common migratory duck whose habitat ranges from the boreal forest of Alaska and Canada to the Mexican and Central American coasts.
In the 1990s, Jeff Warren moved from Michigan to Montana to work at the Red Rock Lakes National Wildlife Refuge as a range technician for the U.S. Fish and Wildlife Service. At the refuge, he learned that lesser scaup populations across North America had declined by more than 50% since the mid-1970s. “They were one of those species that were always numerous and taken for granted,” he told me.
While biologists were aware of the lesser scaup’s decline, they knew little about what the species needed to survive, migrate and reproduce. Although the majority of North American lesser scaup nest in Canada’s boreal forest, Warren knew that large numbers nested where he lived and worked in the Centennial Valley. He realized that he could study the life history of the birds without the helicopters and other costly equipment needed to access the boreal.
In 2004, Warren became the refuge’s wildlife biologist and embarked on a long-term study of the black-and-white diving ducks. “By understanding the biology and behaviors of a bird in your backyard, you can understand a larger picture of continental ecosystems and habitats,” Warren said. “You have to start with where you are and what you know.”
In the canoes, the duck-banding team paddled through the shallow waters, spreading out among islands of reeds to encircle ducklings and their attendant females. With its dense subaquatic vegetation, deep muddy bottom and a surface layer of invertebrates for ducks to feed on, Lower Lake is exceptionally attractive to scaup. It’s also equally challenging for canoeists, yet Liv Lundin, the graduate student researcher on the project, made quick work of the paddling, directing volunteers as they corralled the birds into V-shaped nets. Once herded into the nets’ wide entrance, the ducks slowly funneled into a wire enclosure. Researchers then used long-handled dip nets to extract the scaup, placing them into blue carrier crates and paddling them back to shore.
When the babbling ducklings were unloaded on shore, Lundin knelt and carefully placed a scaup in their lap. They snapped on a metal tag above its ankle, identified its sex and passed it on to a colleague, who measured its weight and bill length. In a year with favorable nesting conditions, the team will place individually numbered metal anklets on 2,000 birds, half of all the scaup banded in North America before the hunting season.
While scaup numbers rose between 2005 and 2015, they have since dropped back to the levels Warren encountered in the 1990s — 15% lower than the long-term average and still well below the target of 4.9 million set by the North American Waterfowl Plan, a framework for conserving waterfowl and wetlands endorsed by Canada, the U.S. and Mexico.
The well-studied ducks in the Centennial Valley inform scaup harvest regulations and management across the continent. The team’s estimates of how many females survive the breeding season are used by the U.S. Fish and Wildlife Service to forecast how populations will respond to harvest and breeding habitat conditions.
Over the last two decades, the Lesser Scaup Project has learned that female scaup at Lower Red Rock Lake gain weight exceptionally quickly, maintain high breeding rates and have an above-average survival rate in this area compared with other nesting areas. These demographic markers reflect the productivity and health of the wetland system, which lies within 30,000 acres of designated wilderness. “Simply put,” said Warren, “it’s a great place to be a lesser scaup during the breeding season.” The project has found that nesting survival is boosted by water-management strategies that slowly raise water levels throughout the breeding season.
“These birds tie the continent together.”
Yet the nesting habitat at Red Rock Lakes is only the beginning of the scaup’s life journey, and the labor of banding is just the start of the yearly study. The ducks that nest at the refuge will soon migrate south in search of warmer wintering grounds. “You can hold a feathered duckling in your palms in August and know that within a few months they will begin migrating south, possibly to Mexico,” Warren said. “These birds tie the continent together.”
Scaup can survive in man-made reservoirs, brackish estuaries, urban bays and the ocean. Most winter in Northern Mexico, along the Gulf Coast and in Southern California, but ducks banded in the Centennial Valley have also been recovered from the San Francisco Bay Area, Washington state and Missouri. Occasionally, lesser scaup from Red Rocks fly north and molt in Alberta.
The bird’s adaptability has a drawback: It exposes the species to a variety of environmental threats. From Warren’s studies of lipophilic contaminants, or pollutants that dissolve easily in fats, he has found organochlorine contaminants in the fat stores of female scaup. Organochlorines include synthetic pesticides such as DDT that are regulated or banned altogether and yet persist in soil and water.
“This species is such an important conservation indicator,” said Lundin. “They have so many stopover sites when they migrate that they rely on the habitat health of multiple ecosystems.”
At the end of the banding day, volunteers brought the carrier boxes back to the shoreline, releasing the ducklings to rest and eat for their long migrations. Later, as he sipped some lemonade at his house overlooking Red Rock Lakes, Warren spoke of the species with the familiarity of a longtime neighbor. “It’s amazing the kinds of questions you can ask when you have a life history of uniquely marked individuals,” he reflected. At the heart of the Lesser Scaup Project is the continued curiosity needed to sustain long-term ecological research.
It helps, he added, that “a duckling isn’t a tough sell. Everybody loves ducklings.”
This story is part of High Country News’ Conservation Beyond Boundaries project, which is supported by the BAND Foundation and the Mighty Arrow Family Foundation. hcn.org/cbb
All research activities were conducted under an Institutional Animal Care and Use Committee-approved Animal Use Protocol and in accordance with permits issued by relevant state and federal authorities.
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