It’s tempting to take the Sanderling for granted: The tiny, speed-walking shorebirds are fixtures on beaches all over the world, easily recognized by how they run along, forever one step ahead of the waves.
For years, this hyperactive sandpiper moved too fast for researchers to even be sure of its migration routes that stretch from the Arctic Circle to South America. Weighing in at just two ounces, Sanderlings were too small to carry the transmitters used to study other birds.
That’s finally changing. New research tools, such as ultra-light transmitters and techniques that analyze where birds have been by the carbon residue in their feathers, are uncovering the Sanderling’s secrets.
The research tells two stories: One is about the miraculous flying prowess of this globe-trotting species. The other is about how those unique abilities aren’t enough to overcome the changing coastal environment that has cut their population of about 300,000 in North America by more than a third since the 1970s.
Both study topics could end up helping other shorebirds as well.
“So many people think of these birds as doing fine, since they’re on every beach from California to the Gulf Coast,’’ said Jess Cosentino, a researcher working on a comprehensive study of Sanderlings in North America. “But the data is showing us they’re in precipitous decline.’’
We spent a good part of our fall wandering the Atlantic coast, following warblers, raptors and shorebirds on the move. On the National Seashore along North Carolina’s Outer Banks, we found ourselves surrounded by crowds of Sanderlings on the near-empty beaches. The protected stretch of shoreline is one of the primary stopover spots for the birds on their migrations down the Atlantic coast.
Here’s a video that gives you a sense of how Sanderlings work together on the beaches:
The long-term Sanderling research, based in Canada, is still underway. But it’s already uncovered some of the keys to how the Sanderling fly distances of as much as 6,000 miles for migration and then return to the same locations year after year:
- The birds are able to build up huge stores of fat, like extra gas tanks on an airliner, that serve as fuel for their flights.
- They can reach surprising speeds for such a small bird, flying up to 50 miles per hour.
- Their wings are long and narrow, perfectly shaped for their long-distance travels.
- They work together in bands to fend off predators and chart their course.
- And they have a precise sense of direction that leads them to their breeding and wintering grounds each season.
The base of the latest research on Sanderlings is at Chaplin Lake in southern Saskatchewan, where salt deposits have created a haven rich in brine shrimp and other food supplies. Its location makes the lake a perfect resting stop for the Central Flyway that runs down the center of the continent.
Each spring and fall the lake is overrun by tens of thousands of shorebirds, many of them Sanderlings that arrive thin and exhausted. And every season, researchers are waiting there to study the birds as they spend several weeks loading up on food for the long flights ahead. By the time they take off again, the birds will have doubled in weight.
Jessica Howell, one of the Sanderling researchers now working as the Northern Plains Conservation Specialist for the American Bird Conservancy, says you can feel how the birds bulk up during the stopover. The researchers handle the birds constantly since their work involves trapping, tagging and attaching transmitters to follow the birds on future flights.
“If you hold them in your hands, you can definitely tell the difference between a bird that’s just arrived and one that’s been there for a while,’’ she said. “You can feel the fat in your hands. They’re almost squishy.’’
Here’s a gallery of the birds:
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Now that transmission devices are light enough to use on Sanderlings, the project is tracking the birds all across the hemisphere with the help of a growing network of radio tracking stations in the U.S. and Canada that pick up signals from the transmitters as the birds fly over.
“It’s important to identify where the Sanderlings are going,’’ said Kristin Bianchini, another of the Sanderling researchers who specializes in toxicology and environmental threats. “It’s obvious that the Sanderlings are migrating, but where exactly are they going?’’
The researchers are trying an additional tactic to learn where the birds have been: They’ve collected Sanderling feathers every season since 2012 and analyze them for atomic elements that signal where the birds have been. This Isotope research – using a sort of molecular fingerprint that’s ingrained in feathers – helps fill in clues on the birds’ travels.
“Their feathers have a unique chemical signature of the environment,’’ said Cosentino, who has collected Sanderling feathers all over South America. “We’re trying to piece together the larger puzzle of where the birds are coming from.’’
As the research identifies the precise migration routes and stop-over spots, that information can be used to argue for protection of key locations the birds need. The more precise the information, the more focused and persuasive the push for conservation steps can be.
The researchers working on the Sanderling project hope their findings will be used to shape public policies that will protect the birds and help set aside land for them or at least provide some protection for the stop-over sites.
They recognize the barriers they’re facing:
Migratory birds in particular have to rely on a string of different countries they pass through, some of which have few resources to devote to caring for birds. The loss of habitat and changing climates aren’t easy issues to address in any country. And the Sanderlings spend much of their year on the world’s beaches that are increasingly developed and crowded with people.
“It’s pretty depressing,’’ said researcher Kristin Bianchini. “But that motivates me to try to answer these questions and help raise awareness about what’s happening with the birds. They need our help.’’
Jessica Howell said that part of the answer is getting the word out that we can no longer take shorebirds like the Sanderling for granted.
“These are such beautiful birds, full of personality,’’ said Howell. “I like to think it’s a matter of outreach. Once people realize how far these shorebirds are traveling, it makes them so interesting and cool. It’s really mind-boggling what they do, and we don’t fully understand how they’re even doing that. There’s some real mystery involved.’’