Scientists tracking a group of young yellow-eyed penguins have been awed at one intrepid bird's 470km hike up the coast.

Otago University researchers investigating the dramatically declining survival rates of the endangered species have tagged a select group of hoiho with satellite transmitters, and were now following their first expeditions into the ocean.

At this stage, 15 of the 23 penguins have moved away from the areas in which they were hatched, heading north up the east coast of the South Island.

But one Catlins penguin, known as Takaraha, has travelled over 470km.


Over the weekend, Takaraha rounded Banks Peninsula, and the latest data showed Takaraha 10 nautical miles east of Gore Bay.

Some of the devices, which triangulate the penguin's position on the ocean's surface, are able to send stored GPS positions by text message every two days.

The tags are attached to the bird's lower back using cloth tape under a small patch of feathers, and are secured with cable ties.

Zoology PhD candidate Mel Young, who has been involved with yellow-eyed penguin conservation and research for more than 13 years, said the research had been a long time coming.

"We've seen a large decline in the number of young birds surviving to adulthood, and as a result the number of recruits has halved over a 70-year period."

A yellow-eyed penguin chick with a satellite tag attached to its lower back. Photo / Jessica Abt
A yellow-eyed penguin chick with a satellite tag attached to its lower back. Photo / Jessica Abt

Ornithologist Lance Richdale studied yellow-eyed penguins from 1936 to 1952, recording survival of penguins up to one year of age at 32 per cent, and subsequent recruitment to breed as adults at 26 per cent.

Recent Otago University research suggested a decline in both juvenile survival, to 20 per cent, and recruitment to breed, to 12 per cent.

"The current recruitment rate is unsustainable. Breeding adults need to be replaced. We need to find out which factors are shaping juvenile survival of yellow-eyed penguins at this critical life stage," Young said.

Otago zoology researcher Dr Thomas Mattern said the study would provide crucial data to assist in pinpointing the factors leading to early deaths in yellow-eyed penguins.

"Survival rates in the first year of a yellow-eyed penguin's life are very low," Mattern said.

"It is vital to determine where they go during that period in order to do what we can to improve their chances.

"There is quite some urgency, as we are facing the loss of the species from the New Zealand mainland in the next few decades."

Though the situation is concerning, Young felt optimistic about the yellow-eyed penguins' future.

"We can use the data from satellite tracking to improve our understanding of important foraging areas and influence the management of regional threats to juvenile survival at these locations," she said.

"Stopping the decline of yellow-eyed penguins relies on evidence-based decision-making, and the University of Otago is doing its part to gather that evidence."