Recent research shows importance of SC islands in migration of threatened red knots

May 10, 2023

Media contact: Felicia Sanders, SCDNR Coastal Bird Conservation Project, SandersF@dnr.sc.gov.

Recent research by the S.C. Department of Natural Resources and its partners has shown the importance of the state’s barrier islands in the epic migration of red knots each year.

Every spring, thousands of small, robin-sized shorebirds stop on South Carolina beaches for a break during one of wildlife’s longest documented journeys. The federally threatened red knots make astonishing migrations each year from wintering grounds at the southernmost tip of South America to nesting grounds north of the Arctic Circle, a roundtrip of over 18,000 miles. During migration, red knots rest and refuel at stopover sites, including Kiawah and Seabrook islands in South Carolina.

An estimated 17,247 knots stop on these islands and at nearby SCDNR Deveaux Bank Seabird Sanctuary, spending an average of 47 days in this area, according to recent research by the lab of noted shorebird scientist Dr. Nathan Senner, local community members and state biologists. That number is 41 percent of the estimated total knot population of 42,000, making South Carolina one of the most important sites for this bird.

SCDNR coastal bird biologists conducted aerial surveys this spring in partnership with the Georgia Department of Natural Resources, to estimate the number of red knots utilizing the Georgia and South Carolina coasts during their springtime migration. Flights are conducted at high tide when red knots are roosting in dense groups on dry sand. Photographs are taken from the air and are helpful in estimating flock size. Information gathered through the surveys is key to understanding the species population trends and movements.

In April 2022, SCDNR biologists partnered with Wildlife Restoration Partnerships in New Jersey to deploy 15 satellite transmitters on knots at Kiawah Island. This is part of a larger Wildlife Restoration Partnerships’ research project to understand knot migration along the Atlantic coast.These tags are attached to the bird’s back, have a solar panel energy source, and are anticipated to fall off the birds within 3-4 months of attachment. Satellite tags use orbiting satellites to determine the exact location of a bird at a given point in time. Researchers can access the location data right on their computer.

Nine of the tags revealed the migration track and chronology of the knots on their way to nesting grounds. Six of the nine tagged knots flew directly to the Arctic (James or Hudson Bay) from South Carolina or Georgia, a nonstop flight of approximately 1,700 miles.The satellite tag data continues to provide evidence of the critical importance of the coastal southeastern United States as a stopover site for knots, said SCDNR biologist Felicia Sanders.

Over the last few decades, red knots have declined by nearly 85 percent. This drastic decline led to the red knot receiving federal protection under the Endangered Species Act in 2015. Disturbance and food availability, especially during migration, are suspected reasons for the drop in numbers.

Ongoing research efforts by SCDNR and its partners is critical in understanding this decline and working toward the conservation of these migratory shorebirds.