Our Changing World: Looking to a wild future for kākāpō

Source: Radio New Zealand

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There are 235 adult kākāpō alive today – each of them has a name, a detailed family tree, a backstory, and a high-tech transmitter that logs their activity.

It’s fun and it makes it easier for people to engage with these charismatic parrots. To talk about You-Tube star Rakiura, and cliff-top nesting adrenaline-junkie mum Rimu and of course, the famously named Attenborough the kākāpō.

But that’s not the ultimate goal of the kākāpō recovery programme, says operations manager Deirdre Vercoe.

“Our vision is to restore the mauri of the kākāpō, or the life force of the kākāpō. And that vision is to have kākāpō nameless, wandering through our forests, booming from the mountains and the hilltops around our cities and towns. Not to have a transmitter on, not to have a name and a well known history.”

So this year, for the first time in the programme’s 31 year history, which began when there were just 51 birds alive, some of the new kākāpō chicks will not be named.

Normally naming happens when a chick has fledged and has passed the 150 day mark since they hatched. It’s then that they get added to the adult kākāpō tally.

Currently there are 92 new chicks alive. They may not all make it but there is hope that the population will reach over 300 birds by the end of this year.

The next question is where to put them.

Home birds or wanderers?

Dr Andrew Digby sits in front of a laptop in a side small room off the large hut on Whenua Hou / Codfish island. On the screen in front of him is a map of the island – populated with different coloured dots. Each represents an individual kākāpō, and it’s movements around it’s home range. And there are no gaps left.

When it comes to how much space a kākāpō needs the estimate ranges between about 15 and 50 hectares says Andrew. Plus different kākāpō will have different requirements depending on the context – a breeding female will need a different space than a juvenile, for example.

It’s this sort of detail that Andrew is hoping to learn about through an ongoing study in which GPS loggers have been added to some birds’ transmitters – to get precise location data from different kākāpō across the seasons.

Tracking kākāpō using their existing transmitters had given them some idea of their movements, but the GPS data is a whole new level of detail says Andrew.

And it is resulting in a few surprises.

The birds move around a lot more than they thought, and there seems to be an unexpected seasonal variation in the movements.

The same GPS loggers were added to male birds released into the fenced ecosanctuary Sanctuary Mountain Maungatautari in July 2023. Some of those birds surprised everyone with their wanderlust, with a few making it out over the fence and into the surrounding farmland and roads.

It was unexpected that they would travel so far, alarming to those caring for them, and it also pointed to one of the key questions Andrew would like answered.

“One thing we don’t know anything about, because we’ve always had kākāpō on islands, is what do they do when they get to big landscapes and how far can they move?…They could go massive distances. We just have no idea.”

As they move towards that future, that would present a monitoring challenge too, says Andrew. Currently the birds sport radio transmitters which log their activity and allow them to be tracked down. The breeding birds live on three islands with information networks and monitoring stations at every nest to keep real-time tabs on the mums’ movements.

As the population grows, and they expand into new habitat, it’s not feasible that the programme will be able to maintain this scale of monitoring. They will have to find another way to keep an eye on the birds, says Andrew, whether that could be eDNA monitoring, acoustic methods, or thermal drones.

The kākāpō challenges

The issue of where to put them is increasingly becoming an urgent challenge. Flightless, smelly and with a freezing threat-response, they are particularly vulnerable to predation by introduced mammals.

But, says Deirdre Vercoe, the programme has run out of “really high quality predator-free island sites”. Their likely next move will be to islands that have low densities of stoats or rats, while continuing investigations of fenced sites, mainland efforts like Predator Free South Westland, and always with an ever hopeful eye on Predator Free Rakiura efforts.

A dearth of good quality habitat is not the only challenge that kākāpō face. The fertility rate of the birds is only about 50%, and disease is a constant threat.

The team has learned that there are some management choices that can help with fertility, and Dr Andrew Digby hopes that ongoing investigations of the genome sequences of each kākāpō will tease out more answers too.

It’s the reason why, although the shift to kākāpō living truly wild has already begun, it will be a long transition says Deirdre Vercoe.

“If you think about that number, even if we do get to 300 this year, there’s still less kākāpō in the world than there are children at my daughter’s school. You know, it’s such a small number. So they are still vulnerable. We can’t walk away just yet. We do have quite a long path to go. But we have made some really good progress.”

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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand