The ability to learn the proper song appears to be influenced by both heredity and experience. Scientists have speculated that a bird is genetically programmed with the ability to recognize the song of its own species and with the tendency to learn its own song. As a bird begins to sing, it goes through a stage of practice (which closely resembles the babbling of human infants) through which it perfects the notes and structure of its distinctive song. In order to produce a perfect imitation, the bird must apparently hear the song from an adult during its first months of life.