plover (plŭvˈər) [key], common name for some members of the large family Charadriidae, shore birds, small to medium in size, found in ice-free lands all over the world. Plovers are plumpish wading birds with pigeonlike bills and strong markings of black or brown above with white below. In flocks they frequent ocean beaches and sand and mud flats, following the backwash of waves in search of the small marine invertebrates that form their diet. The best-known plovers in America are the noisy killdeer ( Charadrius vociferus ), found in pasturelands; the larger (11 in./27.5 cm) black-bellied ( Squatarola squatarola ) and golden ( Pluvialis dominica ) plovers, which migrate as far as 2,000 mi (3,220 km) annually; and the ruddy turnstone ( Arenaria interpres ). The Old World dotterel and the European lapwing are members of the family, as are the crocodile birds of Africa, insectivorous plovers described by Herodotus as picking the teeth of crocodiles. Lapwings are slightly larger than plovers and are found in most tropical and temperate countries, with the notable exception of North America, where they have been extinct since the Pleistocene era. Both lapwings and plovers nest on open ground and dig shallow hollows lined with pebbles or plant debris where their clutch of eggs (usually four) are deposited. Both male and female share the duties of rearing the young. The crab plover ( Dromas ardeola ) of India, Arabia, and E Africa, with its heronlike bill and webbed toes, is so distinct that it is placed in a family by itself, the Dromadidae. It derives its name from its habit of pounding crabs and mollusks to pieces with its heavy bill. Crab plovers lay only one egg per clutch in a deep nest dug into a sand bank. They are easily approached and flock in large groups on coastal mud flats and beaches. Plovers are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Charadriiformes, family Charadriidae. Crab plovers belong to the same order.