Question

The sound-producing organ in a singing bird is _____
(a) Vocal sac
(b) Syrinx
(c) Larynx
(d) Synsacrum

Answer 1

Hint: It is located at the base of a bird’s trachea and it produces sounds without the vocal folds of mammals.

Complete answer: The syrinx is considered as the vocal or sound-producing organ of birds. The sound in them is produced by vibrations of some or all of the membrane tympaniformis, that is, the walls of the Syrinx and the pessulus, which is due to air flowing through the syrinx. This airflow sets up a self-oscillating system that modulates the airflow and creates the sound. The muscles present their hep in modulating the sound shape by changing the tension of the membranes and the bronchial openings. Birds also have a larynx, but unlike mammals, they do not vocalize.

Additional Information: Syrinx is a bony structure at the bottom of the trachea (unlike the larynx which is located at the top of the mammalian trachea). The syrinx and sometimes its surrounding air sac resonates with the sound waves that are made by membranes past which the bird forces air.
The birds can modulate the pitch of voice by altering the tension on the wall of Syrinx. Birds can control the two sides of the trachea independent of each other and this is how some species can produce two notes at once.
Due to syrinx, some species of birds like parrots, crows, and mynas can even mimic human speech. Some species of birds like New World vultures, lack syrinx and so communicate through throaty hisses.
So, the correct answer is ‘Syrinx’.

Note: Main functions of bird song are as follows-
1. A very important function of bird song is to attract males.
2. The quality of bird songs may be considered as a good indicator of their fitness.
3. Another function of a bird song is territory defense. Territorial birds interact with each other using songs to negotiate their territory boundaries.