Crab Bank — Mount Pleasant, South Carolina

A live webcam of the nesting seabirds at Crab Bank allows people to view the island’s inhabitants in real time.

Situated in the Charleston Harbor between two iconic landmarks – Shem Creek and Fort Sumter – rests a narrow strip of land called Crab Bank. The 22-acre islet was documented on maps more than 250 years ago as a sand bar. By the 1950s the sand bar had become an island. As dredge spoils from Shem Creek accreted, the bank built up with sediment. Vulnerable to erosion caused by storms and passing wakes, the island’s shape and size frequently shift. However, Crab Bank has not been completely submerged since before 1979, the first year it was high enough to be used as a nesting site for seabirds.

Since that pivotal time, Crab Bank has proven to be one of the state’s most prolific seabird nesting sites. Fifteen different species of birds, including brown pelicans (seen below), black skimmers, royal terns, and American oystercatchers, use the island for breeding during the summer nesting season, while others, such as double-breasted cormorants and ring-billed gulls, rest and feed on the island during the winter. One of the reasons for Crab Bank’s success as a nesting colony is the island’s natural isolation, keeping birds and nests safe from predators such as raccoons.

The need to protect wildlife within the Charleston Harbor was recognized in 1986 with the creation of the Charleston Harbor Wildlife Sanctuary, which prohibited people from hunting, taking, or otherwise physically disrupting mammals and birds, including eggs, within the harbor. Yet, this designation still did not prevent people and their canine friends from exploring Crab Bank and inadvertently disturbing nests. The island’s proximity to the local beaches and Shem Creek (seen below with Crab Bank just beyond) made it a popular stop for boaters and paddlers.

One particular problem facing nests was the exposure of eggs to the scorching sun when people and their dogs would come ashore, scaring away nesting birds. Visitors would also accidentally crush eggs while walking, as the seabirds build their nests on the ground. The solution came in 2006 when the South Carolina Department of Natural Resources designated Crab Bank, along with Deveaux Bank near Edisto Island and Bird Key off Folly Beach, as a seabird sanctuary.

Today people are no longer allowed on the island from March 15th through October 15th, which is the official nesting season. During the remaining months, the island is open only below the high tide line. Pets and camping remain strictly prohibited at all times. The island is monitored by the South Carolina Department of Natural Resources.

Since Crab Bank became a bird sanctuary, populations have increased dramatically. In its first year as a sanctuary, Crab Bank’s number of royal tern nests rose from 346 to 1,639. Other species have also shown a significant jump in nest numbers. Royal terns can be seen in the below photo.

Though the island itself is mostly inaccessible, people are invited to explore it from the water in kayaks or motorized boats. However, boaters are advised to avoid creating wakes, which aid erosion. The experience of approaching Crab Bank Seabird Sanctuary during nesting season can be overwhelming to the senses, with thousands of birds calling in the breeze, feeding from their parents’ mouths, circling overhead, and guarding their nests.

Paddlers can usually hear the birds before they see them, and when they approach the island, they witness a flurry of activity. The experience of watching wildlife thrive on this small yet important sliver of land is encouraging to those who value the ecology of the South Carolina Lowcountry.

Birds of Crab Bank

Among the many species of seabirds that nest or rest on Crab Bank is the American oystercatcher, seen below. The oystercatcher is a larger seabird, growing to be between 17 and 21 inches in height. Its bold black-and-white markings are distinct, as is its long crimson bill, adapted to eat – what else? – oysters and other bivalves. Oystercatchers lay two to three eggs per clutch each spring, usually in April or May. Their buff-colored eggs easily blend in with the sand, making them vulnerable to human footsteps.

One of Crab Bank’s more prolific residents is the brown pelican (below). A single clutch of three eggs is laid in early spring each year, with both parents tending to the nest. The male collects nest materials such as sticks and marsh grasses for the female, who builds it. Both parents also take turns feeding their young, allowing nestlings to eat from their generous pouches. The brown pelican is unmistakable, with its large, white head, enormous beak, and distinctive gular pouch, which enables it to store the fish it catches through dramatic dives from up to 30 feet.

Pictured below are two varieties of terns. The four birds on the right are royal terns. This little shorebird with its characteristic tuft of a black crest may join thousands of its peers in some nesting colonies. The royal tern nests in May, usually laying one egg but sometimes up to three. Scrapes, or shallow depressions carved out by birds as ground nests, are close together in the royal tern community. Royal terns may lay eggs more than once per season if previously-laid eggs are destroyed.

The bird above on the far left is a common tern. Its distinguishing black cap reaches to its orange bill. The common tern is the most abundant tern in North America, lending to its name. It is a proficient fish catcher and inhabits lakes as well as oceans and bays. The common tern lays one brood a year of two or three eggs.

The above birds are but an introduction to the vast number of species that nest on Crab Bank. By adhering to the ordinances governing the sanctuary, people can ensure the continuing success of Crab Bank as a nesting site.

Crab Bank Map

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