Evaluation of Steroid Sex Hormone Levels in Cockatiels During Their Reproductive Cycle

Abstract

Sexual steroid hormone concentrations differ with respect to the different stages of animal life. For example, hormone concentrations in the reproductive stage show a periodic variation. Studies on variations in sexual hormones in parrots using non-invasive methods as well as the effect of nest-boxes in parrots are less. This study aimed to detect the levels of fecal steroid hormones during the cockatiel reproductive cycle and to investigate the effect of nest-box placement on reproduction. There were 24 mating pairs of cockatiels, and the study was conducted over 13 months. Based on their reproductive status, individual birds were divided into pre-reproduction (PR), incubation (IN), and parent period (PA) in the pre-test; then, the nest box was either temporarily removed for 20 days (RN) or continuously provided (pre-reproduction, PR). The estrogen concentrations measured in the last stage of the PR period and the initial stage of the IN period were significantly higher than those measured in the PA stage, and there were no significant differences in testosterone and progesterone concentrations throughout the reproductive cycle. The nest-box treatments (NB) indicated that eggs were laid 6-13 days after the new box was hung; however, in the pre-test, there was an interval of 30-40 days before the next mating pairs started the next reproductive stage or no reproduction. Estrogen concentrations in PR and testosterone concentrations in RN were significantly higher than those in the other periods during the nest-box treatments. In conclusion, estrogen showed the most significant change among the fecal steroid hormones measured. Nest boxes serve as a positive stimulus for parrot reproduction management and can help non-seasonal reproductive parrots to rapidly enter the next breeding cycle.