Oystercatchers: Haematopodidae

Most species of oystercatchers are migratory, moving from breeding areas during the breeding season to nonbreeding grounds in the winter. Many individuals return to the same locations from one year to the next. All species defend territories from other members of the species during the breeding season, and some defend territories year-round. In oystercatchers that are not territorial during the winter, such as the African black oystercatcher, individuals gather in large numbers for better protection against predators, animals that hunt them for food. This behavior also helps individuals stay warm in cold climates. Oystercatchers sometimes also gather in flocks to forage, or search for food. Foraging flocks in coastal species tend to have no more than fifty individuals, but in inland oystercatchers, groups of as many as a thousand individuals are sometimes observed. The oystercatcher call is commonly described as a trill followed by a loud peep.

Oystercatchers breed during the summer in most parts of the world. All species are monogamous (muh-NAH-guh-mus), that is, a single male breeds with a single female during the breeding season. In many cases, individuals also keep the same mate from year to year. Courtship in oystercatchers is sometimes called "piping" because it involves a male and female singing a single "piped" note together while walking, running, or flying next to each other, making frequent synchronized turns. Nearby pairs often perform the piping routine at the same time. The piping routine is also used to alert other members of the species to the boundaries of a pair's territory.

Females lay between one and four eggs at a time, usually two or three. Nests are simple hollows on the ground, either unlined or lined. Both parents help incubate, or sit on, the eggs. Eggs hatch after between twenty-four and thirty-nine days. Chicks are colored gray-brown to blend into their environments. They are able to leave the nest within a day of hatching. However, parents continue to feed the chicks for at least sixty days after hatching. Most oystercatcher pairs are only able to raise one offspring successfully during each breeding season. Storms can wash away eggs, and chicks are frequently lost to predators.