The Special Design which
nables Birds to Produce Sound
25
Larynx
The human voice box is located in
our throats and therefore, close to
the mouth. Birds, on the other hand,
have their vocal organ situated in the
body. For this reason, birds’ vocal
organ is affected by two airflows, as
opposed to just one as in humans.
Muscles that open and close the air-
ways on both sides of the organ
control the beginning and end points
of the vocal system.
In humans, vocal sounds are produced by the flow of air from the lungs. The
lungs propel air towards the voice box, and the air passing through the vocal
cords there produces sounds that, in turn, are transformed into speech by means
of the bronchia, the tongue, the teeth, the nasal cavity and the sinuses.
The two-branched syrinx, located deep in the breast of a
bird, is situated where the two bronchia divide in the
windpipe. In this complex system, the vocal organ’s
muscles and inner membranes affect the production of
mid-tones. By contraction of the pectoral and stom-
ach muscles, air is directed from the air sacs to the
bronchia and the syrinx, where the air molecules vi-
brate as they pass through narrow passages.
Vibrations of the tympana membrane also af-
fect the frequency of the sound. The pres-
sure of the air sacs in the clavicle
in turn affects the tympana
membrane. The syrinx mus-
cles also affect the flow of
air and consequently, the
quality of sound.
Syrinx
