SONGS AND CALLS
Bird song is nature's most beautiful music. After the relative quiet of winter, the dawn chorus of male passerines awakens us to spring. Birds sing to advertise a territory and to attract a mate. Some birds make an amazing variety of sound while others are nearly silent. Each species has its own unique song, but not all bird vocalizations are song. Birds also use calls to communicate with each other, to beg for food, or to sound an alarm.
Birding by Ear
Birders bird with their ears as well as with their eyes. For a birder, the song of a bird is a valuable clue to identification. No two species make exactly the same sound, but with practice a bird's song, like the voice of a friend, can be instantly recognized. While there is no substitute for hearing the bird in the field, birders can study bird songs at home with mnemonic text descriptions (drink-your-tea), sound recordings, and sonograms.
Not all bird sounds are vocal. This Ruffed Grouse drums loudly with its wings to attract a mate. Woodpeckers drum on hollow trees, and prairie chickens inflate throat sacs to produce a variety of sounds.
Anatomy of a Voice
Birds do not have vocal chords as we do. Their songs and calls are produced through a syrinx. This two-chambered organ enables the bird to produce an amazing variety of complex sounds.