One example is the Western Meadowlark whose loud notes with abrupt pitch changes carry far across the open fields where it lives. Another master singer is the Swainson's Thrush, a creature of
dense forests and streamside thickets. Its song does not carry as far as the Meadowlark, but its slurred, musical whistles are heard through the dense vegetation around the singer. The songs of each
species are suited to their habitat and are constrained by the physical features of their vocal apparatus (see the article about the syrinx and its muscles).
Concluding comments
The late ornithologist, Luis Baptista, described why birds sing in an interview by Claudia Dreifus, reported in the New York Times on May 16, 2000. "They sing, for one thing, because the bachelor
male wants to attract a wife. He also wants to show other males that he's pretty studly, that this is his territory and no one is going to cross the boundaries. A third reason is that the song
induces the female bird's brain to send hormones: it makes her ovaries grow." Despite great variation among song birds, the fundamental purpose of songs is to be successful in breeding.
