Helping New Zealand's Rarest Kiwi

Forest and Bird, Issue 290, 1 November 1998, Page 6

Helping New Zealand's Rarest Kiwi

here are only 150-200 surOkarito brown kiwi, the rarest of New Zealand kiwi. Currently regarded as a sub-species of the North Island brown kiwi, the bird is subject of research which may yet establish it as a separate species. The birds live only in South Okarito Forest which extends for 9800 hectares, near Franz Josef Glacier in Westland. A survey in 1996-97, using 90 listening sites, established a population of 153 birds. Of these 88 have been banded as part of a population recovery plan. Because of fears that, nationally, kiwi are in decline, this tiny population has been given high priority in the kiwi recovery programme The programme, conducted by the Department of Conservation and funded by the Bank of New Zealand, focusses on helping the survival chances of young birds. Research shows that while Okarito birds consistently breed, none of the chicks are known to survive. Their main enemies are stoats,

an animal proving too hard to eradicate with current trapping methods. So young birds are taken from the forest before stoats can kill them and raised in a secure place. By the time they have reached the weight of one kilogram they should be big enough to defend themselves, but to be sure the chicks are not released back into the forest until they are a little bigger. Up to 12 kiwi chicks are taken from the forest each year and raised in captivity but there have been problems releasing them.

The first birds struggled to adapt to the wild and lost weight. Some were killed in territorial encounters with wild kiwi. While one has found a wild mate, only two of those transplanted birds survive. Presently, there are eight chicks released in the forest which are doing ‘quite well’. Birds are now released in summer when there is more food. Unoccupied sites, within the natural range of the kiwi, are used for the releases so there is less likelihood of territorial challenges. Another problem is the way

artificially raised birds become interested in people. Some have been seen on the highway through the forest, though this connexion is only speculative. Release sites are now well away from roads. In a further move to ease the

transition to the wild, chicks are now taken to Motuara Island, in the Marlborough Sounds, and raised in natural conditions. They develop running wild in a forest ‘nursery’ where they can mix with each other but are protected from predators and adult kiwi. When large enough to defend themselves they can then be returned to their home forest. As part of the recovery plan, DoC staff are undertaking research into the social behaviour and population dynamics of a sample of wild birds at Okarito.