Using Spy Technology to Protect One of New Zealand's Rarest Birds

Remote recording devices are being to eavesdrop on a reintroduced population of hihi birds – one of New Zealand's rarest – to see how well they are faring after being reintroduced in the wild.

"Hihi actually means 'first ray of sunshine' and in Maori culture, the birds are associated with health - essentially, they're an age-old indicator of a healthy forest," said Simon Collins, Sanctuary Manager for Rotokare Scenic Reserve Trust (RSRT) in a Zoological Society of London (ZSL) press release.

Scientists from ZSL, Imperial College, and conservationists from the trust are listening to the calls of the hihi birds (Notiomystis cincta) that were reintroduced into the Rotokare Scenic Reserve in the Taranaki region of North Island as part of a study that was published in the February 2019 journal Methods in Ecology and Evolution. In 2017, 40 juvenile birds were released into the reserve.

The hihi is classified as vulnerable in the International Union for Conservation of Nature Red List, so monitoring the population is extremely important. The bird population in northern New Zealand began declining in the early 1800s and now are restricted to a single island. An ongoing recovery program began in 1980 to increase the range of habitats and the number of birds via reintroduction to the wild.

“Hihi are an important native species, who play a crucial role in pollinating indigenous plant species and need a pristine environment in which to thrive. Reintroduction, or translocation, is considered the most effective conservation action we can take to save the hihi bird in New Zealand, but we’ve found it can be challenging to accurately monitor their success,” said Dr. John Ewen, a senior research fellow at ZSL’s Institute of Zoology.

Over the course of the 33-year program, the focus changed from the usual release, observe, and recommend approaches to a new evidence-based approach that has focused on monitoring.

By listening to the recordings, the researchers were able to identify the hihi’s happy or “stitch” call that sounds a lot like banging two marbles together, and they used this to see how the birds were using the area that they were introduced to.

The scientists use the monitoring devices because, “Physically monitoring animals in the field or fitting them with radio-trackers can be invasive, expensive and more importantly can influence the behavior or survival of released individuals, which could drastically influence our understanding and outcome of the reintroduction," Ewen said.

Adding, “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 programs of many other difficult to monitor endangered species globally.”

Oliver Metcalf, a Ph.D. Candidate at Manchester Metropolitan University, said, "using the calls, we found the birds moved from an initial exploration phase around the habitat, to a settlement phase - meaning the birds had established their own territories, or in other words - a sure sign of a happy hihi." This is considered a successful outcome for reintroduction.

This case study that is backed up by scientific evidence shows the strength of this new approach to evidence-based conservation and structured reintroduction biology that will aid conservation organizations in their worldwide efforts to save endangered species.

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