1080 is being credited with a breakthrough in the conservation of kokako in Auckland's Hunua Ranges.

For the first time ever, a pair of kokako have been nesting outside Hunua's intensively managed kōkako conservation area.

It follows Auckland Council's two 1080 drops over 21,500 hectares of conservation and forest land in the Hunua Ranges in August and September.

Council biodiversity manager Rachel Kelleher said the pest control programme appears to have worked.

"It's great to see the pest control programme has been successful in reducing those pests."

Rat and possum numbers in Auckland's Hunua Ranges are at a record low after the drop.

Rachel Kelleher said the operation has been very successful.

"Looking specifically at the pests that we were targeting during the operation, possums and rats, it's well exceeded the planned targets."

No rats or mice were recorded in Hunua's kokako conservation area.

A correction was made to an earlier version of this story, to correct the range over which 1080 was dropped.