American oystercatchers are chunky, medium-sized shorebirds with bold, black head plumage that almost resembles a hood.  Adults have long, thick, pointed beaks that are reddish-orange in color. They have yellow eyes surrounded by a bright orange ring. The upper parts of their bodies are dark brown, and the undersides are white. They have long, pale pink legs and short tails.

Adults are between 17–20 inches (42–52 centimeters) long and 17 to 21 inches (43-53 centimeters) tall. Their bill extends about 3 to 4 inches (7.5-10 centimeters) in length.

Often found along sandy beaches and mud flats, these birds are specialized to live on barrier islands and saltwater marshes in intertidal areas.

Ten years or longer.

These birds have a variety of vocalizations they use to signal to each other, including yelps, whistles and piping noises. They call out to each other while in roosting colonies, during the breeding season, and while challenging other American oystercatchers for control of an established territory.

American oystercatchers are specialized to feed on saltwater mollusks, although they can eat a wide variety of invertebrates, including bivalves, gastropods, limpets, mussels and chitons, along with the occasional fish or crustacean.

The best opportunities for American oystercatchers to forage is when the tide begins to recede, revealing partially-submerged mollusks with their shells still open for feeding.  These birds hunt along sandy beach areas, walking slowly and probing their beaks into the sand. After spotting a bivalve, they quickly jab and plunge their bills into the open shells of their prey, pulling out the contents within. Alternatively, the birds will pry open the shell or use their bill to hammer on the outside until it cracks open.

During the breeding season, American oystercatchers form mating pairs and raise their young as a family unit. In the non-breeding season, they form roosting colonies with other American oystercatchers.

American oystercatchers are monogamous, often pairing up with the same mate year-over-year, and sometimes returning to the same nest site. Males are territorial during the breeding season and will chase out other males from their breeding areas. These birds are quite boisterous during the breeding season; pairs will perform courtship displays and make a series of piping and squeaking calls and vocalizations before mating.

Their nests, called scrapes, are shallow depressions dug into the ground that are lined with sticks. These scrapes are made in sandy or rocky spots near the shoreline, hidden to avoid predation from nest predators like raccoons and skunks. Females lay 1-4 brown-speckled eggs, which they incubate for 24-28 days. Both males and females take turns incubating the eggs, although females do the majority of the nest sitting. After hatching, chicks are covered in soft, sandy-colored plumage, and are ready to walk and leave the nest just a few hours after hatching. Both parents help feed the young for about two months, after which the chicks are large enough to hunt for bivalves on their own.

Once heavily hunted for their plumage and eggs, the American oystercatcher was nearly driven to extinction in the 19th century. Populations have since recovered and remain stable thanks to conservation laws. Current threats to their survival include habitat loss, pollution, human disturbance and the effects of climate change.