Little spotted kiwi have more than doubled in number on their Hauraki Gulf island home in the last five years, according to the results of a recent Department of Conservation survey.

The population of kiwi on Tiritiri Matangi has grown to more than 60 (estimated at 60-80 birds) from about 30 birds in 2002.

DOC scientist Dr Hugh Robertson, who led the survey, said the population was growing strongly, and was as good as could be expected.

"They seem to grow faster on Tiritiri than on other islands due to the rich soils and lack of rats."

Simon Fordham, chairman of the community group Supporters of Tiritiri Matangi and part of the survey team, said how valuable the experience had been.

"Working with such a unique bird was a real treat and a great opportunity to help with its recovery."

Little spotted kiwi are found on just five islands – Kapiti, Long Island (in the Marlborough Sounds), Hen Island, Red Mercury Island and Tiritiri Matangi – of which only Hen Island still has rats (kiore). They are also at the Karori Wildlife Sanctuary in Wellington.

The total population of this threatened bird is about 1500, most of which are on Kapiti.

Meanwhile, an injured female little spotted kiwi from Tiritiri, has been successfully treated at the Auckland Zoo’s New Zealand Centre for Conservation Medicine, and is today being returned to the island.

The bird was clawed by its mate and its bill injured at the time of the kiwi survey two months ago and was taken to the NZCCM for treatment. The wound has now healed and bird is able to use its beak to probe the soil normally again.