Kiwi on the Move
Ecology Update for November 2023
We are thrilled to share some encouraging results from our kiwi monitoring efforts last winter. There is clear evidence that kiwi populations are expanding, at Mataia and Tāwharanui. Both translocated populations have steadily grown in recent years, reaching high densities. While Tāwharanui is fenced, it features an open-ended design that allows animals to move freely around it during low tide. The design of the coiled end-section of the fence does a better job of keeping predators out of the park than preventing kiwi from leaving.
Over the past few years, The Forest Bridge Trust has intensified mustelid control and dog training for kiwi aversion in anticipation of kiwi arriving, while monitoring the buffer zones for signs (sightings or calls) of kiwi dispersal.
Over time, there have been several records of kiwi in the buffer zone. We wanted to investigate how many kiwi are living outside the park and how well they are doing.
The results exceeded our expectations. During the official monitoring season, 487 kiwi calls were detected at 8 of the 12 acoustic recorders deployed up to 6 km beyond the predator-proof fence. Several male-female duet calls were recorded, indicating active breeding of at least four pairs. One site had a relatively high call rate of 4.2 calls per hour, very close to the 5 calls per hour typical of high-density kiwi populations. Additionally, the average call rate at three sites monitored since 2021 has tripled in just two years.
These results provide clear evidence that several kiwi pairs are living and breeding in the buffer zone, and we can expect this population to continue growing and expanding. With these promising results, residents in the Takatu Peninsula can anticipate seeing and hearing more kiwi in the coming years.
In the Mataia buffer zone to the west, we now have clear evidence of kiwi expansion, with one acoustic recorder picking up several calls at a site east of SH16. Our greatest surprise was the detection of a kiwi in one of our monitoring trail cameras at a site in Makarau, approximately 7 km from Mataia!
With kiwi now moving from both ends and the mustelid-controlled bridge well underway, the dream of connecting the east and west populations is now a few steps closer. It is more important than ever to maintain trapping and dog control, even in areas where kiwi have not been recorded yet, as juvenile kiwi are great dispersers and often travel several kilometres before settling down. We expect several of them will be looking for new homes in the next year.
Dr Virginia Moreno – Ecology and Biodiversity Advisor