magpie, common name for certain birds of the family Corvidae (crows and jays). The black-billed magpie, Pica pica, of W North America has iridescent black plumage, white wing patches and abdomen, and a long wedge-shaped tail. It is altogether about 20 in. (50 cm) long. Magpies build large, domed nests in trees. Nest-building is part of courtship. The female alone incubates the eggs. Magpies destroy other birds' eggs and young and kill sickly, wounded, or newborn sheep and cows by pecking. They are scavengers (often collecting small bright objects), but they also eat harmful insects as well as fruits, berries, and leaves. Noisy, chattering birds, in captivity they can be taught to imitate some words. The yellow-billed magpie is found in the valleys of California. The European magpie is closely related to the American; other species are found in Asia and Africa. The magpie-lark belongs to a different family, Grallinidae. Magpies are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Corvidae.