Wellington's Zealandia ecosanctuary is celebrating a milestone, after having banded its 800th kaka.
Zealandia says the native parrot had been effectively extinct in the capital for about 100 years before it started its breeding programme 15 years ago.
Fourteen captive-bred kaka were transferred to the urban sanctuary between 2002 and 2007.
"Since then, they have become one of our biggest success stories," conservation manager Dr Danielle Shanahan said.
She said the programme, together with predator control in the greater Wellington region, had resulted in kaka moving further afield and establishing breeding pairs outside Zealandia's fence.
The original reason for banding had been to monitor the kaka's breeding behaviour, but a new focus was their intelligence.
As part of Zealandia's partnership with Victoria University, researchers are studying how the parrots tackle problem solving, how they learn and remember, and how much they can learn from each other.