The morphologic differences of the trachea and syrinx of five male and five female Touist sp. parakeets were studied. Trachea and syrinx were dissected with the aid of a stereoscopic magnifying glass and the number of rings, the length of trachea and syrinx were evaluated, as well as the length and thickness of the tracheolateral muscle. Trachea of male parakeets had larger amount of rings and was lengther than the female. Tracheolateral muscle of the males was more vigorous and arised in the 43rd tracheal ring while in the females it originated in the 30th tracheal and inserted in first bronchi ring. The syrinx was constituted by cranial rings (five in males and three in females), intermediate rings (resembly a bubble furrowed ventrally), caudal rings (four in both sexes) and the pessule. Sexual dimorphism directly influenced on the syrinx, concerning the morfometry of the musculature and cartilages, making males sound more vigorously.
fowl; parakeet; syrinx; trachea; vocalization
