Two more pairs of kokako have been released into Auckland's Hunua Ranges, as the area is treated with 1080 to make it more habitable for the endangered birds.
The kokako were captured in Pureora Forest Park near Taumarunui on Tuesday and Wednesday and driven up to the Hunuas, south east of Auckland.
The move comes as the Hunuas undergo a 1080 pest control programme.
The first 1080 drop was last month, and another block in the ranges is yet to be treated.
The Pureora forest is a stronghold for kokako, and the idea is to establish new sites for the birds around the country so that if a natural disaster or disease were to strike the population would have a better chance of survival, Kelleher said.
"It's not about getting birds everywhere... It's about putting them in strategic locations where the habitat and management is suitable."
The Hunuas kokako management team were working in conjunction with the Ark in the Park project in the Waitakere Ranges and another project in the Waikato to move the birds around, she said.
There was another movement of birds up to the Waitakeres two weeks ago.
The birds are caught first thing in the morning using nets, Kelleher said.
"They're very territorial, kokako, so the areas that they're present in are quite well understood, and like a lot of birds they tend to be active in that earlier part of the day."
A census last year found there were around 55 breeding pairs in the managed areas of the Hunuas, and another four were found on the edges of those areas.
The latest birds have been brought up from bush that is regularly treated using 1080 and other pest control methods.
"We know that kokako do very well under that method of pest control," she said.
"We're really hopeful that through this pest control work that we're doing at the moment, which will see a lot more of the Hunuas targeted for pests, that we will see those birds start to expand out into areas outside those core managed areas."