quail, common name for a variety of small game birds related to the partridge, pheasant, and more distantly to the grouse. There are three subfamilies in the quail family: the New World quails; the Old World quails and partridges; and the true pheasants and seafowls. No species of New World quail is migratory, but some Old World quail represent the only migratory species of the order. The migratory quail of Eurasia has been known for its phenomenal migrations since biblical times. Quails have high reproductive potentials, with 12 to 15 eggs laid per clutch. The nests are built on the ground in vegetation. The female does the major portion of incubation and rearing. Quails are extremely popular game birds. The Old World quail has never been naturalized in America; in the central and S United States the bobwhite, Colinus virginianus, is commonly called quail (or partridge). The helmet and plumed quails, named for their crests, the Gambel's quail, and the valley and scaled quails are all western birds. They eat harmful insects and seeds and travel in flocks called coveys. Quails are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Galliformes, family Phasianidae.