The syrinx plays an important role in the sound production of birds. Its most important structures are the labiaand the lateral tympaniform membranes that produce sound by vibrating during expiration. Since the left and rightsides of the syrinx are innervated independently from each other, two sound sources are present which can act eithersimultaneously or separately with one side acting as sound source and the other side as air inlet. The bird’s song isgenerated in specific neural brain centres via a seamless synchronization of the respiration and the muscles of theupper respiratory tract, the trachea and the syrinx. Hormones also play a role by influencing the volume of the braincentres in relation to the season. The acquisition of the bird’s song starts with a sensory phase in which the juvenilebird learns the species specific song, and is followed by a sensorimotor phase during which the young bird finetunesits song via auditory feedback.