The Forest Bridge Trust – Volunteers track kiwi calls

Volunteers across New Zealand are again lending their ears to the annual kiwi call count. Over several evenings, volunteers will listen to the distinctive calls of kiwi at designated listening stations. When kiwi calls are monitored consistently in the same locations over several years, it provides valuable insights into the trends in kiwi numbers and distribution. Are volunteers hearing more, fewer or the same number of birds compared to previous years? Are kiwi still in the same locations, or has their habitat range shrunk or expanded? Monitoring over time helps us understand how the kiwi population is faring and how their habitat may change.

With the recent translocation of kiwi to Maunga Tamahunga, we have a new population in our area and there is great interest in understanding their progress and movements. The Tamahunga Trappers have been monitoring the released kiwi using radio tracking, which provides valuable data on the population.

However, that method can only be used for a limited time, after which the transmitters are removed and the primary tool for assessing population success becomes call count monitoring.

Since we know the exact number of kiwi in the Tamahunga population, initiating call count monitoring allows us to establish a baseline dataset calibrated against a known bird count. It’s important to note that chicks born last year are not radio-tracked, so their dispersal (typically averaging 6km) is unpredictable. Therefore, having monitoring posts beyond the release site is essential. These juveniles will start calling when they reach maturity at around two to three years old.

So what is an ideal outcome?

A ‘high density’ kiwi population typically registers around five calls an hour on average. Last year, Tāwharanui recorded an impressive average of approximately 11 calls an hour, indicating a densely populated area. This is why Tāwharanui is now a source for translocations and reintroductions such as at Tamahunga.

Kaipara Kiwi hosted its annual kiwi listening evening at Mataia in early June and the results exceeded expectations. In total, 117 calls were recorded across four sites in two hours, giving an impressive 14.6 calls an hour. However, achieving these targets can be a gradual process, often taking several years of concerted conservation efforts.

With the encouraging growth of the kiwi population across the Forest Bridge, our focus must shift to the protection and care of these precious taonga. Maintaining predator control measures and trapping networks is crucial for kiwi chicks to survive into adulthood. The solemn fact is that only five per cent of chicks born in the wild reach adulthood, due to predation by stoats, ferrets, weasels, rats and feral cats.

Dogs pose another significant threat to kiwi. We urge dog owners to keep their pets on leads in known kiwi areas and to enrol their dogs in our 15-minute Kiwi Avoidance Dog Training. Visit our website to complete an expressions of interest form or email michelle@theforestbridgetrust.org.nz and we will let you know when a training session is scheduled for your area.

Info: https://savethekiwi.nz/,
https://tamahungatrappers.org.nz/,
https://www.facebook.com/KaiparaKiwi/,
https://www.theforestbridgetrust.org.nz/