American Oystercatcher

A boldly patterned shorebird with red-yellow eyes and a vivid red-orange bill, American oystercatchers survive almost exclusively on shellfish—clams, oysters, and other saltwater molluscs. Because of this specialized diet, oystercatchers live only in a narrow ecological zone of saltmarshes and barrier beaches. Along much of the Pacific Coast they are replaced by the similar but all-dark black oystercatcher. American oystercatchers are numerous but sensitive to development and traffic on the beaches where they nest.

American oystercatchers are monogamous and sometimes maintain a pair bond for many consecutive years. Their courtship in early spring is boisterous, with courting birds pacing quickly over the sand in unison, giving a piping call that increases in tempo, and pivoting in arcing patterns around the beach, sometimes taking to flight in pairs. A courting pair often attracts neighboring pairs to begin this display, and sometimes as many as three pairs come together in what scientists call the 'piping ceremony'. Copulation often follows this display. The size of a pair’s territory probably depends on local conditions and ranges in size from about 1.7 to 5.3 acres. They sometimes establish territories within a colony of terns, black skimmers, or brown pelicans. Pairs stay very near one another for the breeding season. Male and female take turns incubating the eggs, and both defend eggs and young, driving away intruders (including other oystercatchers) with calls, chases, and aggressive flight. Young birds can dive and swim underwater to escape predators. After the nesting season the adults and young disperse, often to different locations, for the winter, and younger birds often spend one or more years away from their natal area before returning.