Huîtrier d'Amérique

Identification

The American oystercatcher has distinctive black and white plumage and a long, bright orange beak. The head and breast are black and the back, wings and tail greyish-black. The underparts are white, as are feathers on the inner part of the wing which become visible during flight. The irises are yellow and the eyes have orange orbital rings. The legs are pink. Adults are between 42–52 cm (17–20 in) in length.

Taxonomie

Nom scientifique

Haematopus palliatus

Autorité

Temminck, 1820

Ordre

Charadriiformes

Famille

Hématopodidés

Genre

Haematopus

Répartition et habitat

The American oystercatcher is found on the Atlantic coast of North America from coastal Massachusetts to northern Florida, where it is also found on the Gulf coast, the Caribbean, and south to Brazil, Uruguay and Argentina. It is found also in the Pacific coast of California, Mexico, Central America, Peru, and Chile. In the 19th century they became locally extinct in the lower northeastern United States due to market hunting and egg collecting. After receiving protection under the Migratory Bird Treaty Act, their range extended northward to re-occupy historical habitat in the coastal Northeast. <p>During the breeding season, these birds are found along the Atlantic and Gulf Coasts and from Massachusetts south to Argentina and Chile. In winter, they are found in flocks along the coast from central New Jersey to the Gulf of Mexico. During the breeding season, the American oystercatcher can be found in coastal habitats including sand or shell beaches, dunes, salt marshes, marsh islands, mudflats, and dredge spoil islands made of sand or gravel. During migration and winter, they are found feeding in mud or salt flats that are exposed by the tide. They are also found on shellfish beaches at this time.

Migration

Complete migrants

Comportement

Oystercatchers are closely tied to coastal habitats. They nest on beaches on coastal islands and feed on marine invertebrates. The large, heavy beak is used to pry open bivalve mollusks. Oystercatchers raise a clutch of two or three eggs.<p>The American oystercatcher feeds almost exclusively on shellfish and other marine invertebrates. Oysters are a staple of their diet, as their name suggests, but they also eat mussels, clams, limpets, sea urchins, starfish, crabs, and worms. In general, they use their bills to catch shellfish. As they walk across a shellfish bed, they look for a mollusk with a partially opened shell. When they find one, they jab their bill into the shell and sever the muscle that causes the shell to clamp shut. This can be dangerous, however, as they are sometimes drowned when they don't completely sever this muscle and the shell clamps down on their bill. A strong, tightly rooted mollusk can hold the bird in place until the tide comes in. They also feed by carrying loose shellfish out of the water and hammering at the shell or by probing the sand for soft-shell or razor clams.<p>American oystercatchers first breed at an age of 3–4 years.<p>When courting, the birds will walk together and make a single piping note. This progresses to leaning towards each other, extending and lowering the neck, and running alongside each other while calling. The pair may then burst into flight and fly in a tight formation around their territory.

Conservation

Tendance de la population

stable