New Zealand’s kākāpō has long been endangered, but when a deadly fungal disease struck the country’s vets came to the rescue

Growing up in the north of England, Dr James Chatterton was enthralled by the books of the pioneering zookeeper and conservationist Gerald Durrell and dreamed of saving endangered species. Now, on the other side of the world, Chatterton has done just that, helping to bring the world’s fattest parrot back from the brink.

Chatterton and his team spent the best part of a year bringing in quarantine conditions and trialling new treatments on the frontline of a killer disease afflicting New Zealand’s kākāpō.

“I think most people think our job is to go and stroke the red panda, and cuddle the kākāpō,” says Chatterton, manager of veterinary services at Auckland Zoo’s New Zealand Centre for Conservation Medicine. Even in a normal year, the vet team’s work caring for the zoo’s animals and treating some of the country’s wild creatures is more serious than that, but 2019 was “monumental”, he says.

The respiratory disease aspergillosis began to spread through the endangered kākāpō population last April, threatening to reverse the gains of the bird’s most successful breeding season in living memory.

Kākāpo are not just rare, they are also deeply weird: flightless, nocturnal, with fragrant feathers and a comical waddling run. Males “boom” to attract females, and they only breed every three to six years when the native rimu trees “mast”, or produce large numbers of seeds. Last year was a “mega-mast”, the ripe fruit carpeting the ground, and the kākāpō responded by laying eggs earlier than ever before.

By the end of the southern hemisphere’s summer in February, thanks to intensive intervention by New Zealand’s Department of Conservation (DOC) Kākāpō Recovery Programme, the population of 147 kākāpō had produced more than 80 chicks – a record number, given the seriously inbred species’ struggles with infertility.

Auckland Zoo’s vets took turns working busy stints alongside conservation workers on the remote sanctuary islands where the birds live, in the country’s far south. By April, everyone was exhausted, but finally starting to relax.

Then one of the chicks died suddenly. It was found to have aspergillosis, a brutal infection in which lumps of fungus form in the birds’ lungs and slowly choke them to death.

“It’s hard to diagnose, extremely hard to treat, and usually fatal, particularly in wild birds. You usually just find them dead,” says Chatterton. The disease had only ever been seen in one kākāpō before. “We thought it was going to be a one-off.”

A few weeks later two more chicks died. Then two adult females became ill and had to be put down. “We thought: ‘Something very unusual is going on.’ You’re dealing with a lot of unknowns.”

Facebook Twitter Pinterest The kākāpō patients needed several months of treatment before being returned to the wild. Photograph: Jason Hosking

With aspergillosis, by the time a wild bird begins to display symptoms – or anything unusual shows up in blood tests – it is usually too late to save them. The only way to diagnose the disease in time is using a CT scan or endoscopy to spot fungal growths in the lungs.

The vets and DOC scientists began mapping which kākāpō had shared a nest with the sick birds and which had been on the same food run. The 12 deemed at highest risk were evacuated from their home, Codfish Island/Whenua Hou, and taken by helicopter to Auckland.

Unfortunately, the city’s veterinary CT scanner was being replaced and was out of action for a crucial five weeks, so the vets took the kākāpō to one of the city’s human hospitals. Though they appeared completely healthy, all 12 were found to have lesions on their lungs.

That was a stomach-dropping moment, says kākāpō scientist Andrew Digby, who was based on Whenua Hou at the time. “We were beginning to think it could possibly have affected the whole island … When you’re working with a threatened species, that’s always the biggest fear. They could go extinct at any point. We could lose half the population quite easily in a disease outbreak and set the programme back decades.”

Aspergillosis can be treated with oral anti-fungal drugs if you catch it early enough. “It’s worked really well with other parrots, but each new species you try needs a different dose,” says Chatterton. “We had birds dying, so we went with a high dose, but worried that in saving some we might kill some.”

Facebook Twitter Pinterest One of the kākāpō in care at the zoo. Photograph: Jason Hosking

To get the drugs into the birds’ air sacs, the vets also needed to use a nebuliser. Kākāpō may be the world’s fattest parrot, but their airways are still too small for the droplets produced by an adult human nebuliser, so Chatterton tried a paediatric one. It worked – but New Zealand is a small country, and initially only two were available.

Meanwhile, more at-risk birds were being flown in from the island.

“We peaked at 19 birds in the hospital, each being nebulised for 30 minutes, twice a day, with only two nebulisers. We had to do weekly bloods to make sure we weren’t killing them with liver damage from the drugs, and we had 19 birds that needed feeding twice a day and cleaning.”

Facebook Twitter Pinterest Checking the patient’s weight. Photograph: Jason Hosking

Volunteer vets arrived to help from around the world. Extra pens were built to house the birds. People brought in sheets and duvets from home to cover the floors, and these had to be washed every day. Others went to the city’s regional parks to gather armfuls of the native plants kākāpō like to eat. Chatterton worked every day for five weeks.

By September, 51 kākāpō had been evacuated and scanned – nearly a quarter of the entire population. Of 21 infected birds, aspergillosis had taken nine – though most of the deaths occurred before the anti-fungal treatments started.

Many birds needed months of daily care, but the outbreak was contained. Chicks became juveniles, and while a few died from other causes, most survived and are now counted in the population number: 211, up from just 123 when Chatterton arrived in New Zealand seven years ago.

It is a much happier ending than anyone was expecting. Digby and Chatterton put the team’s success down to the close attention paid to the kākāpō during the breeding season, the detailed records kept about each bird’s movements, and the connections forged between scientists and vets over the past two breeding seasons.

“The only chance these endangered species have is if we all work together,” Chatterton says.

Find more age of extinction coverage here, and follow biodiversity reporters Phoebe Weston and Patrick Greenfield on Twitter for all the latest news and features