TBfree New Zealand is working with environmental groups to stamp out pests in the Rangitoto Range to control bovine tuberculosis (TB) and bring the birds back.

The Hauhungaroa and Rangitoto ranges make up a part of New Zealand's 10 million hectare TB risk area in which TB-infected wild animals have been found.

A bird count was completed in two possum control zones around Taradale last month.

The Bird count will set a base line against which Hawke's Bay Regional Council can, in the future, assess the outcomes of its urban possum control programme and benefits for the biodiversity of the area.

The biggest ever single 1080 operation in Wairarapa's Aorangi Forest Park is about to go ahead thanks to the collaboration of groups that have traditionally been at loggerheads.

TB Free New Zealand is carrying out the 30,000 ha operation in south eastern Wairarapa and even hunters are on board, which is a mark of how far the 1080 debate has progressed.

The birdsong of the vulnerable mohua is being heard in greater chorus in the Catlins after a 1080 drop, the Department of Conservation says.

The population of mohua, one of New Zealand's rarest songbirds, in the Catlins was increasing after a successful joint agency pest control programme last spring, DOC said.