Photo: Otago Department of Conservation
UPDATED 7:24pm: An early summer is thought to have contributed to the deaths of half the yellow eyed penguin chicks on the Otago Peninsula. It's the second blow to the penguin colonies this year - 68 adults died in February from a mystery illness.
The field officer for the Yellow Eyed Penguin Trust David McFarlane says there have also been fewer nests on the Otago Peninsula. "The chick, they've actually been dying at the nest through a combination of what's thought to be starvation and potentially also heat stress."
Penguin chicks dying of starvationStarvation has hit yellow-eyed penguin chicks, killing up to 50% of this breeding season's population on Otago Peninsula. It is the second blow to hit the endangered penguins on peninsula colonies this year after a serious mystery illness killed 68 adults in February.
That ''mass mortality'' event resulted in nest numbers on Otago Peninsula this breeding season being 30% lower than the previous season. Nest numbers were also down in the Catlins by 12%. Department of Conservation ranger Mel Young said early chick losses from this breeding season had been high at some nesting sites and many had died in the first fortnight of their lives.m'Many nests have failed completely or are down to one chick.''
Dead chicks had been sent to Massey University's wildlife centre for necropsy (animal autopsy). ''Starvation has been indicated as the main cause of the chick losses, although the heat may be taking its toll.'' A similar pattern of early chick losses due to starvation also occurred in 2008, when it was thought La Nina conditions with high sea surface temperatures and extreme heat contributed to the deaths, she said.
Additionally, this season was four weeks later than normal, so chicks were at different stages on some beaches. ''It is hard work. We hoped it would be a good year for them but they are working very hard for their food and coming back much later.''
Doc coastal Otago conservation services manager David Agnew said monitoring by all the agencies involved in protecting the penguins clearly indicated many adults had decided not to breed this year. ''Maybe they had some cues it was not a good year to breed.''
While the chick deaths were a concern, last season's mass mortality was more significant as the loss of long-lived breeding adults made more of a impact on population numbers, he said. ''We know only a portion of chicks survive the first year at sea but it'll be a concern if this trend continues every year.''
Those chicks which had survived so far were in good condition and it was hoped they survived to fledge.
The species was also important to the city's tourist economy and it was not expected the latest event would impact on people's viewing opportunities, he said.
Penguin Place's Glen Riley said chick deaths had also been high on the beaches it oversaw but there were many non-breeding birds and adults around. ''It's more typical winter activity, so there is a lot more activity rather than nesting behaviour. It's quite exciting here in the afternoons.''
Yellow-eyed Penguin Trust general manager Sue Murray said the deaths were concerning for the peninsula colonies but it was isolated to Otago Peninsula. 'We wouldn't want more years like this. We'll be very anxious about the next breeding season.''
Breeding at the Catlins and North Otago colonies was similar to last year, if not better, she said.