How do Birds Sing?
Yellow billed duck (Anas undulata).
Birds make their calls by means of an apparatus called a syrinx. This is a cartilaginous device located at the base of their windpipes just above the lungs. The syrinx receives a bronchial tube from each lung and the opening is manipulated by fleshy membranes.
When a bird wishes to vocalize, it contracts its lungs sending a jet of air through the syrinx and by vibrating the fleshy membranes it controls the pitch and tone of the sound.
Birds create complicated tunes by vocalizing using both tubes simultaneously producing different sounds from each side. The crested barbet is able to sustain its incredible ongoing trill by vocalizing with predominantly the one tube and using the other to breathe. Other birds may take shallow breaths and expel air from each side of the syrinx while the other side continues to vocalize. In this way, they may also continue calling uninterrupted for minutes on end.
By Megan Emmett
Birds sing most earnestly in the morning when the air is clear and still and sound travels furthest and loudest....more