Almost all of this year’s yellow-eyed penguin chicks at Moeraki have been taken into care after three were killed, probably by stoats.
Forty-eight of 49 chicks born at the two Moeraki colonies are in the care of Penguin Rescue, staff of which considered intervention the only way to keep them safe.
Penguin Rescue manager Rosalie Goldsworthy said staff last month found corpses of chicks of the world’s rarest penguin that appeared to have been killed by mustelids — stoats, ferrets or weasels.
Previously, she had seen young, vulnerable chicks killed by rats, but these birds were 2 months old and weighed 3kg, she said.
‘‘The animal that’s been killing them took a bite out of their necks — didn’t eat them, wasn’t hungry, but that killing instinct was in their bones.
Moeraki’s 38 nests — of the birds which some experts fear could be on the brink of extinction from mainland New Zealand — had produced 49 living chicks this year.
The birds were now in care at Penguin Rescue’s rehabilitation centre in a specially designed pen, where they were hand-fed meals of fresh small fish by staff twice daily.
As the birds were now ‘‘post-guard’’, a stage of the breeding cycle when they were large enough for both parents to leave the nest in search of food during the day, the only way to keep the birds safe was to intervene, she said.
The one chick that remained in the wild on the peninsula hatched late and was still being cared for all the time by one of its parents.
Penguin Rescue had altered some of its trapping strategy, a hunter from the local runanga had engaged a motion-sensing camera, and they had since caught three ferrets.
Yellow-eyed Penguin Trust science adviser Dr Trudi Webster agreed that predation of this kind was ‘‘quite unusual’’ but she had seen a photograph of one of the dead chicks and she too believed it was likely the work of a mustelid as the predator had ‘‘grabbed the back of the neck’’ of the young bird.
This year ‘‘a lot’’ of stoats had been observed travelling between Yellow-eyed Penguin Trust reserves. And as well as it being a mast year in beech forests, the high number of rabbits in the area could play a role in increased levels of mustelids.
And with 227 nests in mainland New Zealand last breeding season, which looked to have dropped this season to under 200 nests, every bird was important.
Penguin Rescue would keep the birds for another month until they were 3 months old and weighed at least 5kg before they would be released to sea, Mrs Goldsworthy said.
The intervention also could help Moeraki’s adult birds as they no longer needed to feed their young and could gain weight before this year’s moult.
Dead chicks’ bodies have been sent for autopsy.
