Songbird species almost always have a song which is characteristic of the species. In most cases the details of the song are not inherited. Instead, they inherit an ability to learn at a certain age. If a young male White-crowned Sparrow ("Zonotrichia leucophrys") is raised in isolation from the sound of other members of the species, it cannot sing their song. Eventually, it produces a song which is only vaguely like the proper song. But if the experimenter plays a tape of the adult male song, the young will later produce the complete and perfect song when they get to the right age. However, if the young bird is made deaf, it cannot learn the song. From this we learn