Kakapo might require annual vaccinations to protect them against the bacteria that killed three of their number on Chalky Island, off the Fiordland coast, in July.
The erysipelas infection that killed the three kakapo was brought to the island by migratory sea birds, researchers said.
Only 83 of the rare parrots are
left. They are on Chalky Island and Codfish Island, off Stewart Island.
Tests on 15 sea bird carcasses found on Chalky Island showed 10 carried the deadly bacteria, Massey University veterinarian Brett Gartrell said.
"We're pretty sure the sea birds are the reservoir for the infection."
However, it was not known whether the infection was normal in the sea birds or whether it was the first year it had happened.
"What is more likely is that it is endemic in the sea birds in small numbers from year to year. There are literally millions of these sea birds nesting down on these islands," he said.
"The idea of the vaccination is to accept that the [kakapo] are going to be infected from time to time and try to build their immunity to it."
The kakapo recovery team had been vaccinating kakapo against the infection since the July outbreak and yesterday team leader Paul Jansen suggested vaccinations might be needed every year.
"In the future, obviously if we're successful, that job is going to become beyond the realm of possibility. At some stage in the future we're going to have to back away from vaccination."
The effectiveness of the vaccine was not yet known. Tests were being done in Australia to determine that, he said.
The erysipelas saga had cost the programme more than $50,000 so far, Mr Jansen said. However, the increased intervention would pay dividends in the future as the programme battled to bring kakapo off the endangered species list.
- NZPA
