Penguin chicks in care after heavy rain

Eleven of the 53 yellow-eyed penguin chicks at Moeraki are in rehabilitation.

The world's rarest penguin, feared to be headed towards extinction on mainland New Zealand, continues to nest in relatively large numbers on the peninsula under the care of Penguin Rescue.

Although avian diphtheria and mosquito-borne avian malaria were known to be threats to the species, this year a ''serious weather event'' had filled the charitable trust's rehabilitation facility with underweight chicks at risk of starvation, Penguin Rescue manager Rosalie Goldsworthy said.

''There is a pattern to where the starvation happened - it was with the inexperienced mothers and an injured mother,'' she said.

The 11th chick was brought into care while the Otago Daily Times was visiting Penguin Rescue this week.

Nine of the 10 already in care had young mothers that struggled as first-time breeders - female yellow-eyed penguins can begin to breed at 2 years old - and one had an injured mother, she said.

At Moeraki, the birds produced 72 viable eggs this year. There were 41 nests, four fewer than last year, but to date there were 53 chicks - three more than fledged last year.

In November, Moeraki received six weeks' worth of rain, 42mm, in 24 hours.

''But the real issue was the run-off from farms into the rivers and the silt and it just made everything murky, so the water was rough, and it was dirty,'' she said.

The birds began to struggle to feed their chicks after the storm and, earlier than in other years, both parents would head to sea to forage in order to feed the chicks.

''This was really early - normally they don't go post-guard until about Christmas,'' Mrs Goldsworthy said.

''If there were two chicks and they were both underweight, we would take the smallest one, because the other one is clearly doing better in that environment. So we would choose to leave a chick at the nest and hopefully both parents can feed it - that's not always the case.''

The chicks in care, which were between 6 and 8 weeks old, would be fed until they fledged.

The next challenge for the birds was avian malaria, which was largely unknown until last year, when the blood-parasite disease was suspected to have killed 14 Moeraki yellow-eyed penguins, including four chicks.

This year, Penguin Rescue had taken preventive measures to protect the birds from mosquitoes and would begin testing for the disease when the chicks were microchipped at 10 weeks old.

Last year, 50 chicks fledged from Moeraki. Roughly 150 individual birds live on the peninsula, males outnumbering females two to one.