Above, Once found across northern New Zealand, the hihi or stitchbird is now classed as locally extinct across most of its former range, due to habitat loss and fragmentation and the spread of non-native invasive mammal predators.


SCIENTISTS HAVE USED “eavesdropping” acoustic monitoring technology to protect one of New Zealand’s (NZ) rarest birds.

By listening to the calls of hihi birds (Notiomystis cincta) which is classified as Vulnerable on the IUCN Red List – researchers have improved how they reintroduce birds back into the wild.

The study, published in the journal Methods in Ecology and Evolution, was carried out in the Rotokare Scenic Reserve in the Taranaki region of North Island, where 40 juvenile birds were released in April 2017.

A team of scientists from conservation charity ZSL (Zoological Society of London), Imperial College London and the Rotokare Scenic Reserve Trust in NZ were able to track the movements of reintroduced hihi birds (also known as stitchbirds) by recording and listening to their calls.

Dr John Ewen, senior research fellow at ZSL’s Institute of Zoology, said: “Reintroduction, or translocation, is considered the most effective conservation action we can take to save the hihi birdin NZ, but we’ve found it can be challenging to accurately monitor their success.”

Using the recordings, the researchers identified the hihi’s happy or “stitch” call, which sounds like two marbles banging together. They could then figure out how the birds were using the area they’d been reintroduced to, which is the first time that the calls of a species have been used as a proxy for their movement.

They found the birds moved from an initial exploration phase around the habitat, to a settlement phase – meaning the birds had established their own territories and the reintroduction had been a success.

Dr Ewen added: “Physically monitoring animals in the field or fitting them with radio-trackers can be invasive, expensive and more importantly can influence the behaviour or survival of released individuals, which could drastically influence our understanding and outcome of the reintroduction.

“Using acoustic recording devices enabled us to remotely monitor the birds we released, giving us a  true understanding of how they settled post-reintroduction – this has really exciting implications for the reintroduction programmes of many other difficult to monitor endangered species globally.”

  • For more on ZSL’s hihi reintroduction work, visit: www.zsl.org and search for “Hihi New Zealand”.

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