Keas hit by lead poisoning

Keas around New Zealand are giving blood as the Department of Conservation attempts to solve the mystery of why some of the native parrots have extremely high lead levels.

Blood testing of the birds in the Aoraki-Mt Cook National Park last year showed 90 per cent of the birds had lead levels higher than would have been considered safe for humans. Several birds had died of lead poisoning.

DOC staff have been blood testing wild kea populations to determine the extent of the issue. The three areas were chosen based on their different geographic locations and features, to get a good cross-section of the kea population.

"We wanted to get birds from near human habitation and also from wild remote areas to see if there is a direct link to humans," DOC veterinarian, Kate McInnes said.

Successful sampling at one site, Rob Roy Glacier in Mt Aspiring National Park, showed lead was not a problem for those birds.

Testing is also ongoing at more remote locations on the West Coast and near Fox Glacier Village.

"We have chosen these sites to look at the difference between birds that live away from humans, and those which might be popping into town to nibble on houses or look for rubbish. At this stage we don't have enough samples to draw any firm conclusions for the national kea population so our testing will continue until we do," Ms McInnes said.

In the past year Massey University pathologists have examined 10 keas for DOC. One bird was detected with high levels of lead in the liver, but its cause of death was undetermined.

The only kea found dead at Mt Cook in recent months was "Wallace" a juvenile that had hatched in November last year. Department of Conservation ranger Ray Bellringer said the bird had been fitted with a transmitter as part of an Austrian research project. An autopsy suggested he had been killed by a cat.

Since 1991 post mortems have been carried out on 16 birds from Mt Cook. Of the 12 tested for lead more than half had died of lead poisoning.

Blood tests carried out on 18 keas in the village last year showed 16 had lead levels above the level considered safe for human, while the other two birds had elevated lead levels.

The most likely source of the lead was thought to be lead head nails and flashings on buildings within the national park.

A survey of buildings in the Mt Cook Village carried out by a masters student from Victoria University has shown 13 of the 35 buildings looked at had some lead present, with most being in the form of lead head nails. The majority of those buildings were built in the 1960s-70s.

Lead head nails on mountain huts in the park will be replaced over time as the birds have nibbled away the sweet-tasting lead coating on some of the nails.

Mr Bellringer said he believed the nails presented more of a risk to the keas than the flashings which were not as easy for them birds to get their beaks around.