(species Dromas ardeola), long-legged, black and white bird of Indian Ocean coasts, related to plovers and allied species of shorebirds. It comprises the family Dromadidae (order Charadriiformes). Crab plovers are tame, noisy birds about 40 cm (16 inches) long. They flock on beaches and reefs, where they hunt mollusks and crabs, which they then break up by pounding them with their heavy bills. They have a hunched posture on land. Crab plovers dig burrows about 1.5 m (5 feet) deep in sandbanks and lay a single large white egg.