The shell middens along the intercoastal waterway are host to one of the greatest wintering concentrations of American Oystercatchers on the east coast. In the winter, the birds congregate along the shell banks and are conveniently viewed from the ferry. During a rather high tide the other day, there was a large group of them resting. The ferry wake flushed them into the air; as the waves abated, they all settled back to their perches.Oystercatchers are distinctive to identify, with a black head and long orange bill, which they use to snip the adductor muscles of oysters and clams. Since that is the muscle the shellfish uses to keep the shell closed, once it is severed, the oystercatcher can take its time consuming the animal within. They nest in the spring, and I think they have been known to nest on Dewees in the past.
They are listed as a species of high concern by SCDNR, who note that there was a 21 % decline in Oystercatchers in 14 years ending in 2001. Their nests face depradation from raccoons, minks, and possums, and in extremely high tides like we had in May, they may be washed over. Our interns noted that Oystercatcher nests had high mortality last spring, which is worse if they only nest once per year.
Oystercatchers nest on beachfronts, shell mounds, and marsh or spoil islands. They mate for life and raise only one brood per season. In South Carolina, nesting begins early April and ends in late June. Pairs are very defensive during the nesting season. Territorial displays, such as a breeding pair running side-by-side while lowering their heads and calling loudly, are frequently seen near nesting sites. The nest is a shallow depression on a sandy or shelly beach with little or low vegetation. Clutch size is 2 – 4 and eggs are gray with dark spotting. Chicks are dependent on adults for food for at least two months. Oystercatchers are able to fly at approximately 35 days. They are believed to begin breeding at 3 – 4 years. (SCDNR)
You can listen to one here: enature