Vanishing penguin chicks raise conservationists' fears

By ANNE BESTON, environment reporter

All the yellow-eyed penguin chicks from a Stewart Island nesting area have almost certainly died, leading to fears the birds will disappear from the island.

Thirty-one of the 42 chicks in nests on the northern tip of the island are thought to have starved on land.

The rest, which reached seagoing age, were underweight and unlikely to have survived.

The decline in the island's yellow-eyed penguin population was first noticed two years ago. Some nesting sites no longer have any birds.

The Department of Conservation and the Yellow-eyed Penguin Trust made the latest discovery during the first stage of a five-year survey of around 30 to 40 nests along the northern coast.

The Trust and DoC now plan more intense monitoring to find out why the chicks are dying.

Stewart Island-based Department of Conservation spokesman Brent Beaven said it was impossible to know if the chick mortality rate at other sites was the same.

"We have no idea what's happening with them here, it's really been a pathetic result," he said.

Stewart Island was one of three strongholds for the birds, and it was important none disappeared, he said.

About 650 pairs are on the south-east coast of the South Island, and about 1000 pairs are on the sub-Antarctic islands.

Penguin numbers are not yet at a critical level, but they have varied and a conservation campaign was started after population lows in the late 1980s.

Stewart Island population estimates have been unreliable, but the island is thought to have about 100 pairs. Another 60 to 70 pairs are on nearby islands.

Yellow-eyed penguins are the least social of any penguin species and are monogamous. They return to the same nesting sites each year.

Feral cats were at first blamed for the chick deaths, Mr Bevan said. But it became clear that adult birds were not catching the chicks' normal food.

"Chicks need these particularly small fish, but there was some evidence the adults were bringing back bigger fish the chicks couldn't eat.

"Just before chicks go to sea their weight stabilises. That's when we weighed them and they were very light."

Yellow-eyed penguins, or hoiho, regurgitate around seven different fish species for chicks including sprat and red cod.