This study aimed to develop a technique of testicular aspiration and cytology for assessing the status of reproductive activity in small male birds with the swift parrot (Lathamus discolor) as a model species. To validate this technique, cytology was compared with testicular histology and seasonal variations in testicular volume in both wild and captive birds. The described technique of gonad examination and testicular aspiration and cytology was effective in tracking the seasonal variation in testicular volume and spermatogenesis in swift parrots; all 5 stages of spermatogenesis described histologically were identified. But testicular histology provided more information about the cellular architecture of the testes than was evident from cytology. Testicular aspiration and cytology was a reliable and safe technique for assessing the status of reproductive activity during the breeding season in small male parrots. The normal seasonal patterns of reproductive activity of male birds need to be understood for clinical assessment of the reproductive status.