By South Carolina Department Of Natural Resources for Island Eye News
It’s not every day that someone discovers a new-to-science bird migration spectacle.
It’s even more unexpected that such an encounter – in this case, tens of thousands of shorebirds gathering during their annual journey north – would be just a stone’s throw from a metropolitan area. But two years ago, that’s exactly what happened in coastal South Carolina.
In May 2019, South Carolina Department of Natural Resources (SCDNR) biologist Felicia Sanders and a team of researchers confirmed that approximately 20,000 whimbrel were roosting at night on a small island during their spring migration. The team documented similar numbers again in 2020. This single flock includes nearly half of the declining shorebird’s estimated eastern population: a staggering spectacle hiding in plain sight. The findings were recently published in the peer reviewed scientific journal Wader Study. Sanders has devoted her career to protecting South Carolina’s coastal birds. After decades exploring the coast, few are more familiar with the way shorebirds and seabirds use the state’s salt marshes, tidal creeks and barrier islands.
But when Sanders pursued a hunch about the large numbers of whimbrel she saw congregating at Deveaux Bank – a small island just 20 miles south of Charleston – she could barely believe what she’d found. Whimbrel are large, striking shorebirds known for their down curved bills, which are ideally adapted to plucking fiddler crabs from muddy burrows. Like many shorebirds, they migrate incredible distances across the western hemisphere each year, facing threats including habitat loss and overhunting along the way. In the last 25 years, whimbrel declined by two-thirds across the Atlantic Flyway, the eastern portion of their population. The discovery of a roost of this size – the largest known for the species – is of critical importance to successfully protecting this rare shorebird. After spending the winter on the coasts of South America, whimbrel fly thousands of miles north to nest and raise young across subarctic regions of Canada and Alaska. They typically make just one stop along the way. For many of these birds, that stop is in South Carolina, where they rest and feed on rich coastal nutrients that will fuel their breeding season. At high tides and at night, when feeding habitat and other safe resting sites are inundated, whimbrel flock together for safety. They seek large, isolated offshore refuges like Deveaux Bank, where disturbances from people and predators are minimal. But relatively few such places remain along the Atlantic coast. In early 2019, Sanders’ discovery inspired a collaboration between the South Carolina Department of Natural Resources, the University of South Carolina, the Cornell Lab of Ornithology and the conservation nonprofit Manomet to census and film this nocturnal roost during peak migration in April and May. For optimal visibility, the shorebird biologists, along with videographers specializing in filming sensitive wildlife, converged on Deveaux on full moon nights as flocks of whimbrel arrived during and after twilight. A shorebird roost of this magnitude offers a glimpse of the abundance that was once widespread across the Atlantic coast and now stands as a testament to South Carolina’s commitment to coastal habitat conservation.
Deveaux Bank Seabird Sanctuary is closed year-round above the high-water line, apart from areas designated by signs for limited recreational use (beaches on the ends of the island, facing inland). From March 15 through October 15, some of the island’s beaches are closed for seasonal nesting of coastal birds and are demarcated by fencing. Dogs and camping are prohibited year-round.