Discovery of new kiwi population 'most significant in recent times'

Friday, 5 July 2019

A new population of our rarest kiwi was discovered after a conservation ranger heard a kiwi call in a recording from the area.

A new population of our most endangered kiwi has been found on a remote plateau in South Westland, a welcome surprise to authorities who say it is a vital boost for their conservation efforts.

A group of Haast tokoeka – the most endangered kiwi subspecies, with an estimated wild population of fewer than 500 – has been found in an isolated part of South Westland.

The exact number of birds in the group is unknown, but it is thought to contain at least 16 individuals. They were found by Department of Conservation (DOC) rangers in early April, after one ranger had heard what sounded like a kiwi on a years-old recording taken from the area.

The new birds increase the existing Haast tokoeka population by up to five per cent, and add much-needed genetic diversity to the existing population.

One of the new Haast tokoeka birds found living in the wild.

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The find was unexpected, as wild Haast tokoeka are only known to inhabit a steep, mountainous area along the Haast ranges some 20 or 30 kilometres east.

The first sign of the new population came from acoustic monitoring, which is regularly undertaken in the conservation estate to monitor birdlife.

The new population was found a reasonable distance from the known population.

A ranger was listening to audio taken from Junction Hill and heard what they thought was a kiwi. Other rangers who listened to the recording agreed.

Although the recording was several years old at that stage, an expedition was launched in early April this year.

'We didn't really know what to expect,' said Inge Bolt, a senior DOC ranger based in Haast.

'In a sense, we didn't expect too much, but we knew if we did find something it would be significant.'

A team of four rangers went to the area and played kiwi calls at night, hoping for a response. They quickly received one.

In the first night, they found three kiwi, and on the second, another two. A second visit to the area found another kiwi, bringing the total to six. All were fitted with radio transmitters.

The discovery was surprising for several reasons.

A 12-day-old Haast tokoeka chick from the known population.

The birds were found on a plateau with acidic soil and low vegetation, which was notably different than their known habitat on the Haast ranges.

'It was a really interesting discovery in itself,' Bolt said.

'People were thinking that kiwi wouldn't live there, but we were proven wrong.'

It was also unclear how the kiwi had survived predation from stoats, which kill the majority of young kiwi in the wild. One theory was that the harsh environment had fewer predators, but this was not proven, Bolt said.

Testing of feathers taken from the birds showed they were genetically distinct from the main population, which could add much needed genetic diversity to the population.

'It's massively significant for the population,' Bolt said.

'What it's going to enable us to potentially do is pull some of those genetics into the main population, so we get a much larger genetic diversity, which we all know is important for long-term sustainability.'

What happens to the population now is yet to be determined, but a decision will be made in conjunction with the local rununga, Te Rūnanga o Makaawhio, Conservation Minister Eugenie Sage said.She said it was the 'most significant kiwi discovery in recent times', and was a testament to the hard work of DOC staff.

'It's really exciting news, and I was just delighted to speak to the staff that had been involved in the monitoring and then doing the reconnaissance out to Junction Hill,' she said.

'It's hard work in the field… It highlights how much we still have to discover in areas like South Westland and Fiordland, which are obviously quite remote and where DOC has been improving the scale of its monitoring in recent years.'

The Haast tokoeka is one of three subspecies of the Southern brown kiwi, one of the five kiwi species. It has a conservation status of nationally critical, one level below extinction.

More acoustic monitoring would likely be undertaken in the area to see if there were more kiwi in the vicinity.