Opinion | Leave This Wondrous Island to the Birds

By Deborah Cramer

Photographs by Damon Winter

Deborah Cramer is a visiting scholar at M.I.T.’s Environmental Solutions Initiative and the author of “The Narrow Edge. A Tiny Bird, an Ancient Crab, and an Epic Journey.”

About 20 miles south of Charleston, S.C., at the mouth of the North Edisto River, a small, horseshoe-shaped sandbar rises above the water. The claim of land is tenuous on Deveaux Bank, about a half-mile offshore. At high tide, it’s three-quarters submerged. Deveaux’s sand is continually shifting as swirling currents build it up and wash it away. In some years, the island disappears altogether.

This ephemeral spit of sand, about 250 acres, is a gathering place for tens of thousands of birds. It has been home to the largest population of brown pelicans on the East Coast and to large populations of terns. There are skimmers, gulls, oystercatchers, red knots and more. Of the 57 coastal water bird species that South Carolina has identified as of “greatest conservation need,” virtually all are found on Deveaux.

A boat ferried scientists to the low-lying sandbar.

Opinion | Leave This Wondrous Island to the Birds

An oystercatcher on the bank.

Not least among them is the Hudsonian whimbrel, a large, brown-speckled sandpiper whose curved bill looks like the crescent of a barely new moon. The island is a critical way station for whimbrels on their long back-and-forth migration between South America and northern Canada.

Until a few years ago, no one knew where, exactly, most of these birds roosted at night as they fattened up for the final leg of their journey. Then, as dawn broke one day in 2014, Felicia Sanders, a biologist for the South Carolina Department of Natural Resources, watched astounded as flock after flock of whimbrels flew from the island out over the water. She couldn’t quite believe her eyes: She usually found whimbrels during the day, out in the marshes feeding on fiddler crabs, but at most she would spot a couple of small, scattered flocks. That morning, staggering numbers were leaving the island, which, as it turned out, was the largest nocturnal roosting place for these birds in the Western Hemisphere.

“This,” says John Fitzpatrick, the longtime executive director of the Cornell Lab of Ornithology, “was one of the most mind-blowing discoveries in the history of 20th- and 21st-century ornithology.”

The Hudsonian whimbrel is one of eight known species of curlews. Two are thought to be extinct. One of those, the Eskimo curlew, was once abundant in the Carolinas. Their vast numbers reminded John James Audubon of the immense flocks of passenger pigeons that would darken the skies. But like the passenger pigeon, the Eskimo curlew was hunted relentlessly, and as the Western prairies were cultivated, the bird lost its mainstay food: the Rocky Mountain grasshopper. The last confirmed sighting of this curlew, once perhaps the most common shorebird in North America, was in 1963.

Slender long-billed curlews were also once multitudinous on the South Carolina coast. Now they are rare: Just one has been reported on Deveaux this year. An easier way to see this bird is to view Audubon’s 1834 painting, in which two stand on the shore with the Charleston skyline rising in the background.

Whimbrels were also plentiful in South Carolina. A soldier stationed on Charleston Harbor’s Morris Island during the Civil War described what he estimated as millions on a sandbar in front of his camp. Ornithologists reported “hundreds of thousands” migrating along the coast, and flocks of “forty thousand” were seen flying over Cape Romain.

But that was then. The number of whimbrels migrating along the Atlantic flyway has dropped precipitously; a recent analysis by Environment and Climate Change Canada, the national environmental agency, found a 74 percent decline in their numbers since 1980. This is part of a larger drop-off in shorebird populations worldwide that has been described by experts as a “catastrophe.”

In 2010, a detailed study by the Western Hemisphere Shorebird Reserve Network, an international partnership of public and private organizations in 17 countries seeking to protect critical shorebird habitat across the Americas, estimated the total number of the Eastern breeding population of Hudsonian whimbrels at 40,000. (A Western group was put at 26,000.) Now, the long-term survival of these birds is in question, and the preservation of their nocturnal roosting places along their migration route is essential. The Delmarva Peninsula and the coasts of Georgia and South Carolina are key staging areas, with Deveaux Bank the most important.

There are few predators on the island, and the vegetation is sparse, ideal for roosting on the sand. And surrounding it is a cornucopia. South Carolina, thanks to years of dedicated conservation, is home to one of the largest expanses of salt marsh along the East Coast – some 350,000 acres – with 30 percent of its coast preserved.

Opinion | Leave This Wondrous Island to the Birds

Whimbrel returning to Deveaux Bank for their night roost.

At night, the birds rest on Deveaux. During the day, they fan out across the salt marshes to feed. Evolution has made them ideally suited to this routine. They are, of course, strong fliers — a daily commute of dozens of miles to feed is just another day in the life — and “the curve of the whimbrel’s bill nicely matches the shape of fiddler crab burrows,” according to Cornell’s Ornithology Lab. “The bird reaches into the crab’s burrow, extracts the crab, washes it if it is muddy, and sometimes breaks off the claws and legs before swallowing it.”

Whimbrels are thought to be highly faithful to their roosting sites, stopping at the same place year after year. But there is no guarantee Deveaux Bank will be there when they return. One hurricane could sweep it away, as Hurricane David did in 1979. That is why biologists are wasting no time studying these whimbrels and this island, which the sandy currents have built back up to its current size.

Opinion | Leave This Wondrous Island to the Birds

The size and position of Deveaux Bank change every year.Source: Google.

After the 2014 discovery, Ms. Sanders returned to the bank again and again over the next few years. She determined that when twilight and spring’s highest tides coincided, whimbrels began arriving on the island en masse. In May 2019, she assembled a team to count the birds. They began late one afternoon as the sun was setting. Long lines of whimbrels streamed onto Deveaux, the flocks extending as far up the river and south over the ocean as they could see. When darkness halted their work, they still heard the murmuring calls and rustling wings of incoming birds. On a night when a clear sky and a nearly full moon bathed the island in light, they counted 20,000 birds — half of the entire Atlantic population.

To understand why so many whimbrels gather on Deveaux and what makes the island vital to their migration, the scientists needed to know where the birds went during the day and how they used the island at night. To open a window onto that world, they caught two whimbrels in 2020 and outfitted them with small, state-of-the-art GPS solar-powered tracking devices. Buoyed by their success — they tracked one bird to its winter home in a remote region of Venezuela — they set their sights on the spring of 2021 to fully deploy additional transmitters and follow the birds on their hemispheric journeys.

But catching a whimbrel isn’t easy. Especially on Deveaux. The scientists, led by Maina Handmaker, a graduate student at the University of South Carolina, made their first attempt on March 27, when the moon was nearly full. By May 10, they still hadn’t caught a single bird there. They tried nets hidden in the sand and triggered by explosive devices without success. The birds simply would not enter the target areas. “When you’re outsmarted by whimbrel for weeks on end,” Ms. Handmaker said, “it reinforces how little we understand how they think. I have immense respect for these birds.”

Opinion | Leave This Wondrous Island to the Birds

Maina Handmaker watching for the evening arrival of the whimbrels.

Opinion | Leave This Wondrous Island to the Birds

Felicia Sanders, center, setting up the nets.

Time was running out for the scientists. Only a week or two remained before the whimbrels would begin departing for the Arctic. The scientists made their final plan. This time, they would use mist nets, nearly invisible volleyball-like nets suspended from poles that catch birds flying or walking into them. They made a bold decision to trap on a newly emerging sand bar just off Deveaux, where none of the team had been at night. May 11 was most likely the last possible day to trap there in 2021. The wind was expected to be light, the evening high tide would concentrate the birds on the highest part of the bar, and in the darkness of a new moon, Ms. Handmaker hoped the birds wouldn’t notice the nets.

I joined the crew. We arrived on the low-lying sand bar late in the afternoon, set up the net while the birds were still away feeding, then retreated to our boats to wait for whimbrels. Out in the river, rocking in the swell, we watched as thousands of returning whimbrels streamed onto the sandbar. When the sun had fully set, we made our way in the total darkness and ripping currents back to shore. Even though we couldn’t easily see, we hoisted ourselves from the boats, splashing as little as possible so as not to frighten and flush any of the roosting birds. Complicating matters, a storm was moving in, lighting up the sky in the distance.

Ms. Handmaker tiptoed slowly toward the net. It was so dark, she had little sense of how far she’d walked, and so quiet she was sure the birds had eluded her once again. But when she turned on her headlamp, 14 whimbrels stared back at her from the net.

As the storm approached, we went to work, removing the birds from the net and placing them in cloth cages. The scientists measured and weighed two birds, took blood samples and gently fitted them with transmitters. Then they released the birds on the beach near the water, where we watched them fly into the darkness. With the storm nearly upon us, we were forced to free the rest of the birds, hurriedly packed up the net and all the equipment, and headed home in the pounding rain. Still, it was a successful night: The team had begun to know whimbrels.

When the tagged birds return from the Arctic, the biologists will learn how the abundance of food on their foraging grounds, and the energy spent commuting back and forth from Deveaux, may affect their reproductive success. This information, in turn, will inform the development of conservation policies to safeguard whimbrels and the other shorebirds of Deveaux.

Deveaux Bank is a state-designated seabird sanctuary, but two of its beaches are still open to the public. Dogs and camping are prohibited, and much of the island is closed down to the low-tide line, but people are still a persistent and serious threat as birds are nesting, or attempting to nest, in areas open to the public.

It is not just the wary whimbrels that are threatened. When visitors frighten pelicans, terns and black skimmers off their nests, eggs and chicks may perish in the heat. Black skimmer nesting failed on Deveaux in 2019 and 2020. The birds are back again this year, but boats continue to pull up on the island and a nearby sandbar.

A 2012 paper on Deveaux’s birds concluded that “partial island closure” there couldn’t adequately protect the birds from human disturbance. The National Audubon Society says that one of the issues facing the island is human incursion. “Although the island is posted, boaters with their unleashed pets pose a major threat to nesting seabirds,” according to the group. “They step directly on the nests, crushing eggs, and disturb the birds so that they are off their nests long enough for the sun to damage the eggs.” And human pressure on the birds is only increasing. Coastal South Carolina’s population is growing — Charleston County’s rose by more than 17 percent in the past 10 years.

Abby Sterling, research biologist and director of the Georgia Bight Shorebird Conservation Initiative for Manomet, a conservation nonprofit with a focus on shorebird recovery, told me: “Deveaux Bank provides unparalleled habitat for whimbrel and other shorebirds and seabirds. It has no equal in all of coastal South Carolina. But it is fragile: Human disturbance can be harmful to birds. When such a large proportion of whimbrels and so many other shorebirds depend on this single small island, it is imperative that people respect and appreciate Deveaux from a distance.”

Opinion | Leave This Wondrous Island to the Birds

Deveaux is a place of international conservation importance.

What can be done? Close Deveaux, and the sand bar emerging nearby, year round out to the low-tide line, to everyone — recreational boaters, beachgoers, sports and commercial fishermen — and prohibit flyovers by helicopters and drones.

Deveaux deserves international recognition as a place of conservation importance. It more than meets the criteria as a Site of Hemispheric Importance, the highest designation given by the Western Hemisphere Shorebird Reserve Network. To Ms. Sanders, Deveaux offers what she said is a “glimpse into the abundance and wildness that was once widespread across the landscape.” By documenting the importance of Deveaux to whimbrels and other shorebirds, she added, she hopes it will “inspire protection of the island so future generations can also witness thousands of whimbrel setting off at first light.”

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