Charitable organisation Penguin Rescue is at the forefront of a "huge commitment" to save the yellow-eyed penguin population along the North Otago coast.
Moeraki Penguin Rescue manager Rosalie Goldsworthy said there were "two boys for every girl" at Katiki Point in Moeraki and the "gender imbalance" was not ideal for reproduction.
Last week the very rare hoiho was voted Bird of the Year for the second time in five years in the Forest & Bird poll, raising awareness of the critically endangered species.
Despite the voter popularity, the hoiho’s survival on the mainland is on a cliff-edge.
"When populations get stressed it’s not uncommon for them to have a gender imbalance", Ms Goldsworthy said.
"In Oamaru they’ve had a number of male hoiho. They haven’t had a female there for a number of years, so if one turned up, she would just get swamped, overpowered by the interest, and leave again."
Ms Goldsworthy said in the fight to "save each and every penguin" they were also working to combat the vagaries of climatic extremes and coastal erosion impacting the habitat.
The ten local Penguin Rescue members, often supplemented by international team members helping the cause, had been "furiously planting" between Oamaru and Dunedin to combat the coastal erosion impact on water quality in the penguin habitat.
"We have more hoiho in the Waitaki than there is on Stewart Island or in the Catlins, we’ve got a higher population here. So the care should be higher too", Ms Goldsworthy said.
She hopes that a "national and local" campaign will help broaden their effort to save hoiho.
Meanwhile, ongoing close monitoring of female hoiho was necessary to ensure the species’ survival.
Last moulting season at Katiki they lost five adult female hoiho — one as a result of malaria at the reserve, Ms Goldsworthy said.
Another four "just disappeared".
Last week hoiho at the reserve had laid six eggs.
Ms Goldsworthy said the current nesting pairs had bonded closely which boded well for the future of their chicks.
"The wife swapping is almost like there is a hierarchy in the social order in penguins, so if an important female dies, then there is an effect where each one steps up a groove."
Despite a successful mission last year to save 70 hoiho chicks from a novel gyrovirus that caused respiratory disease, they were preparing to do it again this November, which was a "huge commitment".
Last season the society monitored the fledge of 57 chicks from 40 nests which had been a "significant number".
Hopefully the colony would do even better this year.
"If we get even 10 of them back, we’ll be thrilled and delighted", she said.
Ms Goldsworthy said the departure of young penguins was a stressful time for the penguin population, as they learned to fish before heading north to Banks Peninsula.
She said hoiho faced disease and starvation although the major contributor to the hoiho’s decline was not fully understood.
"It could be sick, it could not be fishing well, it could have a disease, which means it can’t dive to the bottom to get fish. We don’t know why."
There were an estimated 130 hoiho nests locally.
Last year they helped 104 penguins at the reserve.
A newly installed biosecure area had been built at Katiki by Penguin Rescue co-leader and resident "penguin wrangler" Robbie Verhoef.
It included an "isolation chamber" to isolate the hoiho from the highly pathogenic avian bird flu.
