Gonadal Cycles of Wild Budgerigars, Melopsittacus undulatus (Psittaciormes: Platycercidae)

Abstract

Non-breeding wild budgerigars from semiarid and arid regions of Australia had small testes with the seminiferious epithelium consisting of two or three layers of spermatogonia, or small and undeveloped ovarian follicles. During breeding testes increased in size by 30-40 times, and gonads passed through spermatogenic or oogenic cycles similar to those in birds that breed in non-arid regions of the world.