The international science effort to determine what's killing kākāpō has begun DNA-sequencing fungus collected from the birds' island home.
Researchers want to rule out the presence of an antifungal resistant strain of the disease aspergillosis, detected in seven dead kākāpō since April. Another 13 birds are still being treated for the disease in mainland vet hospitals, with some not expected to survive.
Dr Andrew Digby, Department of Conservation kākāpō science advisor, says DNA-sequencing would identify exactly what strains of the disease were present on Whenua Hou (Codfish Island) where all the sick birds had come from. Results would be shared with United Kingdom researchers working on a global study of the fungus, including a rise in treatment resistant strains.
Kākāpō is a critically endangered species - there are just 142 adults and 72 chicks in the world. At the height of the current crisis, around 45 birds had been removed from Whenua Hou. Massey University's Wild Base Vet Hospital, Dunedin Wildlife Hospital and Auckland Zoo Vet Hospital are caring for the quarantined kākāpō.
Digby says no new sick birds have been reported in the past three weeks, and 31 had now been returned to Whenua Hou. The international response was ongoing with around 20 individuals or organisations in the United Kingdom, United States and Australia now involved.
"Kākāpō are so unusual and weird that people are willing to give up their time and help."
The cost of the response has been estimated at up to $500,000 and Digby said "many, many tens of thousands dollars" worth of blood samples had been collected. These were now being tested for the presence of viruses and bacteria.
"The other theory is that there is something else. Some other pathogen which has weakened them and compromised their immunity, which means they are then more likely to succumb to the aspergillosis."
It had been a rollercoaster year for the Kākāpō Recovery Programme, with a record 86 chicks being born. Digby said the number of birds on nests, combined with an incredibly hot and dry summer which is very good for the fungus, may have also contributed to the disease outbreak.
"It may well be that it was just this freak set of environmental conditions."
One of the sickest birds is at Auckland Zoo vet hospital. Esperance-2-B is one of the birds Canvas magazine followed on a behind-the-quarantine lines look at the emergency response.
Yesterday, Dr James Chatterton, the Zoo's veterinary services manager said the chick "has held her own over the last week". On three "nail-biting" occasions, Zoo vet staff had considered euthanasia, but each time, she had rallied.
"Her prognosis is very poor . . . but yesterday, she was running up to the top of one her branches, jumping off and gliding to the floor. She was really showing off."
Chatterton said 10 kākāpō were still in residence at the Zoo, including an adult male with an illness unrelated to the aspergillosis scare. Two chicks had recently returned clear CT scans, but would not be returned to Whenua Hou for some time.
"In a pet bird, if it wasn't going anywhere, you would treat for weeks or months. So we don't have an exit strategy precisely yet, but it's great news they seem in normal health now . . . things are as good as we could have hoped for, without getting everyone's hope up. We've got many, many weeks and months ahead of us, and things can change in that time."