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Research Magazine > ARCHIVE > Summer 01 > Article

Shorebirds' Survival
by Helen Fosgate

To the American oystercatcher, a black-and-white bird with a distinctive orange bill and chunky pink legs, nothing is more appealing than an undisturbed strand of white, Atlantic sand.

Of course, people tend to be rather fond of those same beaches, and the competition poses a problem for the rare, native shorebirds. Unaware beachcombers trample eggs, which are nearly invisible against the sand. Boat wakes swamp nests and wash out eggs. And where development has stripped dunes of natural, stabilizing grasses, blowing sand smothers nests. Also, the oystercatchers’ diet — almost exclusively oysters, with a few small crabs and other shellfish on the side — makes them especially sensitive to pollution.

This isn’t the first time the American oystercatcher has been threatened by the encroachment of humans. Like many shorebirds, the oystercatcher was hunted to near extinction in the early 20th century for its long, showy feathers, which adorned fashionable ladies’ hats.

But this time around, the oystercatcher has allies: researchers like Sara Schweitzer, a wildlife ecologist in the UGA Warnell School of Forest Resources who is gathering information she hopes will guide coastal management policies to ensure the species’ survival.

“We know oystercatchers prefer sandy beaches, but so do people,” Schweitzer said. “So we’re monitoring how well they’re faring on other sites like sand spits, dredge spoil deposits and oystershell rakes. This information will help us develop management strategies to improve these sites and the birds’ survival rate.”

In research funded by the Georgia Department of Natural Resources, UGA graduate student Clay George is working under the direction of Schweitzer and DNR biologist Brad Winn to gather needed information about the birds.

A mid-winter survey counted more than 150,000 sea- and shorebirds of 65 different species off Georgia’s coast, including 487 American oystercatchers. But the numbers are much higher in North Carolina and Virginia, and scientists want to know why. It could simply be that Georgia is near the southern end of the oystercatchers’ range. Still, while hundreds of the birds winter on Georgia’s coast, researchers know little about their migratory habits, nesting success or how they’re affected by pollution.

“Oystercatchers have ties to the human food chain, so they’re an excellent indicator species of the overall health of the coastal ecosystem,” Schweitzer said. “We can condemn oysterbeds for people, but the birds depend on them, even when the oysters are contaminated.”

When oystercatchers flee areas of increased human activity, some find sanctuary on the few remaining undeveloped beaches and sandbars along the Atlantic: places like Georgia’s Sapelo, Ossabaw and Cumberland islands. One flock winters on Little St. Simons. On a sandbar north of Georgia’s Altamaha River, 20 to 30 pairs nested this past year from March to early August — with varying success.

“We don’t know whether they pair throughout the season or split up when their nests are destroyed,” Schweitzer said. “Also, we don’t know if they return to the same nesting site each year, regardless of whether they were successful the year before.”

To gather such information, Schweitzer, George, Winn and Wildlife Conservation Society veterinarian Terry Norton, who works at St. Catherines Island Wildlife Survival Center, are netting oystercatchers and tagging them with colored leg bands.

“We knew how much more we could learn if we marked the birds,” Schweitzer said. “It will allow us to follow individuals and pairs from season to season.”

Since December 2000, they’ve captured 24 birds, including five willets, three marbled godwits and 16 oystercatchers. Once captured, the scientists move quickly to put the birds into dark, vented boxes so they calm down. One by one, the birds are weighed, measured and marked with colored and stainless steel leg bands. Norton takes blood samples to check for accumulations of heavy metals and diseases like avian influenza and the West Nile virus. He also collects fecal samples to test for internal parasites and bacterial pathogens.

“Oystercatchers are charismatic birds that can live up to 15 years in the wild,” Schweitzer said. “We hope their survival is just a matter of educating ourselves about their needs and developing guidelines that the public will support and follow.”

For more information, e-mail schweitz@smokey.forestry.uga.edu.

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Struggling to survive, the American oystercatcher competes with people for prime real estate on sandy beaches of the Atlantic Coast.
Photo courtesy of Sara Schweitzer