Chapter 35 Diseases of the Respiratory System
The respiratory system of birds is uniquely designed for flight. The nostrils are found in the cere, the area around the most dorsal surface of the upper beak. The cere of male budgies is usually blue, whereas in females it is pink. Discoloration of the cere may indicate gonadal tumors in budgerigars. The nasal cavity is divided by a septum. An infraorbital sinus is located ventromedial to the orbit of the eye—this is the site of swellings involved in sinusitis. The glottis (the opening to the trachea) is located on the dorsum of the tongue and is not covered by an epiglottis. The trachea bifurcates immediately after the thoracic inlet, and the bifurcation is the location of the syrinx, the voice box of birds. The lungs are paired and are firmly attached to the dorsal body wall.
Respiratory problems are frequently seen in pet birds. The design of the respiratory system predisposes birds to these problems. Bacterial, viral, and mycotic causes of respiratory symptoms are addressed in Chapter 34. This chapter deals with diseases that are specific to structures in the respiratory system: the nasal cavity, sinuses, trachea, syrinx, lungs, and air sacs.
