American Oystercatchers

Posted on September 03, 2012

American Oystercatchers are a common sight in Hilton Head Island’s marshes throughout the year.

In the United States, these striking birds can be found in coastal habitats ranging from Massachusetts to Florida and along the Gulf of Mexico and the Pacific coast of Southern California. South Carolina serves as the winter home to the majority of the American oystercatcher population.

The American Oystercatcher (haematopus palliates) is an easily-identifiable shore bird. This large bird tends to be two feet in length and sport a three-foot wing span. It typically has a white belly, black head and dark brown back. The most distinguishing feature, however, is its bright orange/red beak. Juveniles usually have dark brown beaks that change color upon maturity. On Hilton Head Island, oystercatchers probe the mud in our saltwater estuary systems around low tide. At high tide, they may be seen walking or running around shell beds and beaches.

At low tide, oystercatchers forage around oyster beds and other intertidal areas. These animals are aptly named due to their tendency to feast on local mollusks such as oysters, mussels and clams.

Their beaks are specially designed to pry open bivalves and then sever the muscles that clamps the mollusk shut. Once the muscle is detached, the birds are able to suck the animal out of its shell. However, this operation can be a dangerous endeavor for young oystercatchers. If the muscle is not severed, the mollusk will shut, trapping the oystercatcher and drowning it in the incoming tide.

Adults may also use their beaks as a hammer to break apart mollusk shells. These opportunistic creatures may also prey on crustaceans, insects, jellyfish and even small fish. Oystercatchers will reach breading maturity by the age of 3. They will then choose a mate for life.

In the early spring, couples begin to make their nests together on banks above the high tide water line. Their nests can be laid along shell mounds, beach fronts and marshes. Oystercatchers typically lay two to four eggs in shallow depressions. Communal care for eggs has been noted in some groups of oystercatchers. One male and two females may tend up to six eggs in two different nests. In either case, the eggs will incubate for about a month before hatching.

Although chicks will learn how to fly within 35 days, they will stay with their parents for up to two months, relying on them for food. Young oystercatchers tend to flock together once they have left their parents.

In most coastal states, the oystercatcher is a species of special concern. The global population is only about 72,000. In total, there are less than 10,000 of these birds in the U.S. today. In the early 1900s, egg harvesting and plume hunting nearly brought these animals to extinction. In 1918 the Migratory Bird Act Treaty protected these animals from such hunting. The birds have been able to make a comeback, but have still not reached their original range or population numbers.

Today, a number of factors affect both nesting space as well as a lack of reproduction in the species. Oceanfront development, avian and mammalian predation and over washes from tides and boats as well as human disturbances have all caused a serious decline in oystercatcher populations.

However, these impressive birds can be seen year-round in the Lowcountry in relatively healthy numbers. Keep your eyes open for this signature shore bird and enjoy a glimpse into the unique world of the American Oystercatcher.

The H2O Nature Center, which features live reptile and amphibian exhibits and hands-on displays, focuses on the wildlife and habitats of the South Carolina Lowcountry. Nature tours, apparel, gifts, books and bicycle/fishing gear rentals are also available. To reserve a tour with Master Naturalist Kathleen McMenamin, call (843) 686-5323 or visit h2osportsonline.com.

By kathleen McMenamin, Master Naturalist, H2O Sports
Photo courtesy of Googie man at en.wikipedia