The Trust’s local tawaki rangers monitored nests at three sites in South Westland during the 2020 tawaki breeding season, Knight’s Point, Jackson Head West and Gorge River, to establish breeding success. Monitoring discontinued when chicks left the nest to creche. Crèche areas were checked for signs of predation. Many of these nests also had trail cameras set up to observe breeding success and predator activity and the final sets of images are being analysed through the Jobs 4 Nature programme. More details to follow once all the data is in.
The additional effort to monitor predators during the 2020 breeding season was because it followed a beech mast (massive seedfall event) and it was expected we would see many early chick deaths due to stoat predation, as was observed in the 2016 season. This did not eventuate. It is difficult to measure subtleties of the beech mast (timing and local severity), and the subsequent increases in mouse, rat and stoat populations. Despite this year’s findings, the dynamic forest change led by a beech mast is still present as a threat to all forest dwellers, including tawaki chicks. We hope to learn more once the imagery from the three colonies has been fully analysed and reviewed.
Summary of breeding success, noting that, unless food is unusually abundant or very scarce, and assuming no predation, one chick is usually raised per nest.
|Site||Nests monitored||Chicks seen at nest – pre crèching||Breeding success to crèching||Predator / disturbers filmed||Predation events at nest||Predation at creche seen|
|Knight’s Point||14||14||1||Possum; rat||0||0|
|Jackson Head West||25||22||0.88||Possum; rat; deer; stoat||0||0|
|Gorge River||24||20||0.83||Possum; rat; deer||0||0|