Learning a Song

■ Perhaps on hearing the beautiful singing of a songbird, you have been amazed at what seemed to be an inborn ability. But does the bird sing this song just by instinct? Perhaps not entirely.

Experiments with the white-crowned sparrow show that this bird must learn the song of its species. If raised separate from adults of its own kind and thus unable to hear their singing, the white-crowned sparrow will sing but will develop its song abnormally. On the other hand, if during the time when it is between ten and fifty days of age it hears even recordings of normal songs of its species, it will learn to sing normally. And, in fact, it will imitate the particular dialect of song it hears.

But would it learn to sing just any song it hears? No. If, during this same period, recordings of another species are played, it will not learn that song. It seems that the sparrow needs training to learn its normal song, but also it has some internal guidelines that enable it to focus on the particular song for its species and that lead it to reject other songs. This, in effect, is a built-in insurance that the white-crowned sparrow will not learn the song of another species.