The New International Encyclopædia/Extinct Birds

EXTINCT BIRDS. Various birds may be called ‘extinct’ instead of ‘fossil,’ because their species have expired since the present geological era began, or, in several cases, since written records began to be made. In most cases these were birds that belonged to ancient and senescent races, such as the ratite moas (q.v.) and their kindred; or they were species of extremely limited range, or of degenerate powers, due to an insular habitat or other unfavorable surroundings. See Extinct Animals.