
Seabirds such as these brown pelicans on Crab Bank Seabird Sanctuary in Charleston County nest in dense colonies from March to October on islands along the South Carolina coast. (SCDNR photo/Christy Hand)
South Carolina’s 2024 seabird nesting season has come to an end, and counts from nesting colonies have been compiled by South Carolina Department of Natural Resources’ (SCDNR) biologists.
From March to October, seabirds such as brown pelicans, royal terns, Sandwich terns, least terns and black skimmers nest in dense colonies on islands along the South Carolina coast. Most of the nesting occurs on seabird sanctuaries, islands owned and managed by SCDNR, and on islands in Cape Romain National Wildlife Refuge in Charleston County.
Each year, SCDNR biologists conduct an aerial survey in partnership with SCDNR Law Enforcement Division pilots to photograph seabird nesting colonies along the coast during the breeding season. Aerial photographs are then analyzed to count the number of nests for each species at each colony.
SCDNR biologists counted 677 black skimmers nests statewide, including 397 nests from Crab Bank Seabird Sanctuary. Brown pelicans were slightly down to 4,265 nests, likely due to a combination of predator pressure at Bird Key-Stono Seabird Sanctuary and limited nesting habitat at Deveaux Bank Seabird Sanctuary. Crab Bank, Bird Key-Stono and Deveaux Bank are all in Charleston County.
Royal tern and Sandwich tern nests totaled 7,206 and 2,314 respectively, with the largest colonies on Tomkins Island Seabird Sanctuary in Jasper County (4,672 royal terns and 1,425 Sandwich terns), marking an encouraging comeback after the site was inactive for the last two years. Gull-billed tern nests numbered 236 in the count, spread out in small colonies between Crab Bank Seabird Sanctuary and on four islands in Cape Romain National Wildlife Refuge.
Least tern numbers were gathered using ground count techniques. The state threatened seabird nests totaled 747 statewide, with 401 from natural sites and 346 from alternative sites such as rooftops and dredge spoil areas. Long-term monitoring of least terns in South Carolina indicate they are in decline, and this year’s nesting effort is once again below average.
While these numbers are used to monitor population and nesting trends, they do not represent the productivity (chick success) for these species. Seabird nesting success will continue to be negatively impacted by the increasing severity and number of storms, abnormal high tide events, as well as disturbance from human activity at nesting sites.
To help nesting seabirds, SCDNR urges beachgoers to be aware of and respect site-specific closures and regulations.