You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
New Zealand's endangered kakapo could be at risk from a potentially fatal virus newly discovered in the South Island.
Beak and Feather Disease (BFDV) has been found in the South Island for the first time in native yellow-crowned parakeets in Fiordland.
It had already been discovered in red-fronted parakeets on Little Barrier Island, and in wild Australian eastern rosellas, an introduced species.
University of Canterbury scientist Dr Arvind Varsani said the potentially fatal disease, which targets parrots, was discovered during a collaborative study which tested more than 780 birds of seven threatened and endangered parrot species, including kakapo.
It was found the two North Island cases involved viral isolates from the same strain, while the South Island case involved a completely different virus strain.
"From that, we can say we have had two clear introductions of the disease."
The disease causes birds to lose their feathers, can cause beak deformities and weakens their immune systems so they are susceptible to other infections which can kill them.
Since first discovered in Australian parrots, it had spread around the world.
In some overseas captive facilities, it has resulted in 50% losses, Dr Varsani said.
"Given that circoviruses, such as BFDV, evolve rapidly, they can easily move across hosts, and thus spread among different species of parrot."
Kakapo Recovery Programme manager Deidre Vercoe Scott said they did not know if kakapo was susceptible to the virus because they were genetically different from many parrots.
There was also the possibility the virus could have been in the South for a while, meaning some kakapo could have been exposed to it.
However, testing of the birds in the programme had not shown any antibodies from the virus.
"We'll continue to monitor.
"There is some concern until we know they are not susceptible, or if they do get it, how they react."
In a small population a virus such as BFDV could have a "big impact".
The programme had recently translocated from Codfish Island eight kakapo to Little Barrier, where the disease had been found, with the knowledge it might be a "one-way trip" for the birds.
"We weighed it up. It is a significant site for kakapo to breed in, which outweighed the risk."
Dr Varsanni said the study highlighted the need for continued, systematic BFDV screening in captive-breeding facilities as well as in wild populations of parrots in New Zealand.