The Department of Conservation has found at least four endangered penguins have died as a result of dog attacks in the past six months, and a recent autopsy confirmed another dog-related penguin death.
That penguin was one of a pair that had been wounded and received help at Penguin Place but for some reason did not moult. So they were kept at the colony's hospital until the next moulting season, and they had become waterproof enough to go back to sea.
Penguin Place owner Howard McGrouther said the tagged pair were then released, but about three months later one of them was found dead.
"It's so needless. The autopsy showed it was in a very good condition so it would have survived by itself."
It was also a waste of resources, as the cost of staff time and fish put into saving the bird was about $6000 - all funded by visitors to the ecotourism business, he said.
The hospital had cared for 89 penguins through the summer and had an 84% release rate.
Many were underweight, which had been identified as a major cause of them not surviving at sea, and some were injured. Penguins needed to be about 7.5kg at the time of moulting but some of those found were only 4kg, he said.
"We bring them home and feed them up."
While that was a big job, it was worth it to give the penguins a second chance at life, he said. One penguin had been in the hospital three times, but in between those times had reared nine chicks - "chicks we would not have had if we hadn't saved her the first time".
Sue Downton and Colin Wolverson, of Oamaru, had also noticed more underweight penguins needing treatment at their hospital.
The pair, with the help of two volunteers, still have 13 penguins in care and have had a busy season, at one time having 23 in their hospital.
Seeing them head back out to sea was the reward although there was no guarantee they would survive, Ms Downton said.
"It's fantastic; while there is no guarantee, at least we have given them a second chance."
They do a "beach watch" every day as well as talking to visitors to educate them about behaviour around the penguins.
While they did receive some help from Doc, they relied on donations to do the work and pay for the many kilos of fish needed and the medicine, some of which cost $2 a tablet, she said.
Katiki Point Penguin Charitable Trust, Moeraki, honorary ranger Rosalie Goldsworthy and a team of volunteers look after two colonies of yellow-eyed penguins at Barracoutta Bay and Katiki Point.
Ms Goldsworthy said the trust had rehabilitated 300 penguins in the past seven years, which was significant, given the birds were endangered.
"It shows the species is under stress. The situation is dire. We only rehabilitate the ones that are reported to me. That is a small percentage of the ones who [are in trouble]."
She worried every time she sent one of her charges back out to sea.
"I understand it is not easy for them out there."
People needed to be aware that if they could approach a penguin on a beach, it meant the bird was not well and they should report it.
They should also not use flash photography.
"There is no such thing as a tame yellow-eyed penguin. They are wild birds and if you can get near them, they need help."
