KEY POINTS:
A kakapo has slowly been nursed back to health at Auckland Zoo after his body weight nearly halved from lead poisoning.
The male kakapo, called Lee, was found to have lost a significant amount of weight during a routine check when he was moved from his Codfish Island home.
One of the original 24 founder male kakapo from Stewart Island, Lee was moved from Codfish to Anchor Island in April with one other kakapo.
Department of Conservation staff were doing a health check on the bird when they noticed his poor weight.
Auckland Zoo vet Dr John Potter, who provides veterinary services for the kakapo recovery programme, said it was thought the problem could just be related to ageing.
It was not known how old Lee was but he was probably at least 30. The critically endangered birds are thought to live up to 100.
Dr Potter said blood and other health tests gave no indication of the reason for Lee's weight change, which then further dropped by 1kg to just 1.2kg. The bird was flown to Auckland Zoo's Centre for Conservation Medicine for further testing.
Dr Potter said x-rays and other tests showed nothing out of the ordinary until further testing of blood samples showed signs of lead.
The lead, which may have come from a fishing sinker or lead pellets from a shotgun, appeared to have been excreted by the bird but had contaminated his blood.
"When Lee arrived, we didn't have tremendous expectations for him because we didn't know what was wrong with him, and he was at a dangerously low weight. We eliminated the probability of a tumour, but our test for lead revealed toxic levels in his system."
Lee was given chelation therapy, where a calcium compound was used to help bind the lead in the blood, reducing its toxic effect and making it able to be excreted.
"It's hugely pleasing to see Lee so healthy now. He's put up with twice daily tube feedings to enable us to get his weight up to over 1.7kg and for a bird that's been held in captivity for the first time, he's really pretty chilled out."
Dr Potter said Lee had been fed up on juvenile parrot food, a powder mixed with water.
DoC's technical support officer for the National Kakapo Team, Daryl Eason, said lead was a common contaminant in the environment from decades past but Lee's problems appeared to be isolated.
"All our other kakapo on both Anchor Island and Codfish Island are in good health, with no weight loss. However, as a precaution, we are at present blood testing and performing routine health checks."
Lee was bound next week for Codfish Island, his old stamping ground for 25 years.
"We think he'll settle in very quickly, and while he will likely lose up to 200g, just with the stress of travelling back, we expect he'll put on quite a bit of weight within a short period."
Mr Eason said Lee, like the other kakapo, would be fitted with a transmitter. "We'll be keeping a close eye on him."
