High nest survival, but variable reproductive output in the Superb Parrot (Polytelis swainsonii)

Quantifying the reproductive output of species is fundamental in understanding population dynamics, life history, and in conservation management. The use of multiple metrics to quantify reproductive variation allows for a clear interpretation of the species’ breeding biology and is often needed for robust models of population trajectory. Using measures of nest survival, clutch size, brood size, and nestling body condition we quantified reproductive output and annual variation of the Superb Parrot Polytelis swainsonii over 5 years in Canberra, Australia. We found consistent nest survival probability, maintained at over 89% throughout the nesting period in all years of study, but variation in all other metrics. Clutch sizes of Superb Parrots varied annually, and we found seasonal declines in both clutch and brood sizes. Furthermore, nestling body condition also varied annually and by order in which hatching occurred. The annual breeding performance of this bird has implications for conservation assessment and provides critical baseline data. Continuing to address critical knowledge gaps in Superb Parrot ecology and biology should be prioritised to better inform management and resolve the uncertainty that remains in the species’ conservation status.