By Rebecca Fox on Wed, 16 Dec 2009
News: Dunedin
Toxins such as organic pollutants have been ruled out as the cause of deformities in endangered yellow-eyed penguins at Okia Reserve last summer.
Massey University wildlife scientists have been investigating the unusual skull deformities which occurred in eight of 34 penguins and was so severe they were not able to survive in the wild.
"It's unprecedented to have so many birds in a small area affected," pathology resident Kelly Buckle, from the Wildlife Diseases Association conference in the Catlins, said.
Earlier research, presented at a yellow-eyed penguin symposium in Dunedin in August, indicated genetics, diet or heat stress were unlikely causes of the deformities, which included a significantly shortened beak.
Heavy metals had also been ruled out.
The final toxicology results from a deformed bird and two normal birds, one from the Catlins and another from Otago Peninsula, might not have solved the mystery but had ruled out toxins as a cause, she said.
A "good percentage" of toxins normally tested for were ruled out such as organic compounds like PCBs or DDT, although low or "background" levels were present, as was expected.
"None show any evidence they are responsible for the deformities."
While it was disappointing not to be able to provide the Department of Conservation Otago with any answers, the tests provided a baseline for the population, showing the levels of toxins normally present if there were problems in the future, she said.
It also showed the "background" levels of toxins were much lower in Otago than in other places such as the northern hemisphere.
"The Catlins control was slightly lower [than the Otago one] in human-made organic compounds which fits as Dunedin has more humans."
She hoped to publish the results of her research so the results could help with other toxicology work with sea birds.
Early indications were that this season's chicks at Okia Reserve did not have the deformities.
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