Fourteen rare Okarito rowi kiwi have been taken to vets in the North Island with sore bottoms.
The birds have gone to Palmerston North's Massey University's Wildbase Hospital and Wellington Zoo's Nest wildlife veterinary clinic.
They were staying on a predator-free island in the Marlborough Sounds before being returned to Okarito, when Department of Conservation staff noticed things were not quite right.
Conservation services manager biodiversity Jo Macpherson, of Franz Josef Glacier, said the birds needed treatment a few times a day, and that could not happen on the island in the sounds.
She stressed that it was a minor infection, possibly yeast, and the vets were not alarmed.
