An outbreak of avian diphtheria has hit southern Otago Peninsula yellow-eyed penguins.
The outbreak comes at a critical stage for chicks that have recently hatched and is requiring some hands-on care by the Department of Conservation.
Doc ranger Mel Young said avian diphtheria seemed to hit the penguins every second year and samples from as many chicks as possible were being sent to Massey University's wildlife unit for testing.
It appeared the chicks caught a virus and then contracted the diphtheria as a secondary disease.
In the meantime, affected chicks were being given antibiotics and fluids in an effort to encourage them to eat, as those who died usually suffered from renal failure or from not eating.
"So far so good. We have had some die but some are responding and are eating and putting on some weight."
The next week or two would be critical for the penguins, she said.
Monitoring had found 422 nests from North Otago to the Catlins, with many chicks now about one or two weeks old, she said.
Nest numbers were up in the Catlins and about the same as the past two seasons in other sites.
Aside from the diphtheria outbreak, there had been a few "early losses" of chicks and those bodies had been sent to Massey for necropsy.
A lot of older birds up to 20 years old were still "getting it on" and birds as young as 2 had joined the breeding population, Ms Young said.
At Sandfly Bay, where there had been concerns about the public impact on the penguins, nest numbers were up to 10, although two had failed.
"Several new birds have entered the breeding population. The measures we have taken are improving the situation."
A lot of juveniles had been seen on the region's beaches, including one spot that had attracted 12 to 18.
"That is amazing. Hopefully, they'll hang on and get through moult."
A pair of yellow-eyed penguins, an adult and a juvenile, had been visiting Karitane beach regularly since the end of October.
Historical reports had noted penguins on the beach, although a bird was killed there by a dog two years ago, she said.
"They seem to be settling in, which is very exciting."
The community was keeping a close eye on the birds and it was hoped they would settle and start breeding there, she said.
Doc would be closing Boulder Beach from December 1 to February 28 to allow the chicks born there to grow uninterrupted by the public.
