Okārito Kiwi Sanctuary

In 2003, genetic research showed the birds living within the sanctuary’s boundaries were distinct from brown kiwi – a species on their own. They were given the name 'rowi'.

With a population of only about 375 mature birds, rowi are one of New Zealand’s most threatened species and ranked as ‘threatened: nationally critical’.

When first established in 2000, Okārito sanctuary had one of the world’s largest stoat trapping operations –1500 tunnels were laid in a pattern across 11,000-hectares of core kiwi habitat. However, in summer seasons when the native trees produced a great deal of seed (mast years), rat populations exploded, followed by stoat populations. Even the intensive trap network couldn’t save the kiwi chicks.

BNZ Operation Nest Egg™

Today, Okārito kiwi sanctuary relies largely on Operation Nest Egg to boost its rowi population.
Eggs and wild-born chicks are removed from the forest and taken to the incubation facility at The West Coast Wildlife Centre in Franz Josef. Using this method, more than 90% of fertile eggs hatch successfully – if left in the wild, the success rate can be as low as 5%.

Newly hatched chicks are kept in an enclosure in Franz Josef to develop their nocturnal instincts, and are then released onto a predator-free island in the Marlborough Sounds. Other islands are also being assessed to see if they are suitable for use as creches.

The young birds stay on the creche island until big enough to defend themselves against stoats. At that point they come home. Care is taken not to release the juveniles into territory occupied by adult pairs, as rowi are fiercely territorial.

Twenty-five juvenile rowi were released back into the Okārito sanctuary following the 2006/2007 and 2007/2008 breeding seasons. In 2010, 36 young birds from the 2008-2009 breeding season were brought home, with 20 released into North Okārito Forest. This area was once part of the rowi's natural range, but no birds are known to have lived there for many years. The 2010 release marked a big step for the Rowi Project.

Future management of rowi

As with Haast tokoeka, researchers believe the best way to boost the slow-growing rowi population is to ensure more chicks survive. While this can be achieved using Operation Nest Egg in the short term, managers want to find ways that are more sustainable and less invasive for the birds in the long term. To that end, in coming years, predator control will be trialled alongside Operation Nest Egg to find the combination that best protects the birds in the wild.