Hauturu – Reviving the kokako

The kokako, sometimes called the blue-wattled crow, is one of New Zealand’s many unique species. It is about the size of a magpie, with strong legs for hopping and climbing trees. Its beautiful blue-grey wings are rounded and only good for gliding, not sustained flight. Both male and female adults have blue wattles around their throats. They are vegetarians, eating foliage, flowers and fruit of many species.

Kokako once graced the forests of Coromandel and Great Barrier Island with their haunting bell-like song, but were not known to have ever been present on Hauturu.
In the early 1980s, 33 kokako were transferred to Hauturu after the Wildlife Service had eradicated feral cats and the island was able to offer them a safe haven. They came from the Waikato-Bay of Plenty region, where native forest was being felled. In 1994, the last two remaining kokako from Great Barrier Island were captured and taken to Hauturu.

Many visitors to the island report seeing them strolling on the ranger’s lawn or hearing their haunting song at dawn.

By the 1990s, the population was estimated to be around 130 birds. In 2013, the Department of Conservation (DOC) conducted a survey of the kokako on Hauturu. The survey indicated that there were around 450 pairs of kokako on the island. Blood samples were taken from some of the birds to gauge their health, as well as conduct DNA work to study their genetic diversity, as the founding population had been relatively small. The DNA sampling indicated that there were probably few females in the founding population.

This is not surprising considering the birds came from an area where nesting female birds would have been vulnerable to attack by mammalian pests. It is thought the Hauturu population may have reached carrying capacity.

During June and July of this year, a DOC biodiversity team has been on Hauturu to capture juvenile kokako. They have managed to transfer 20 young birds to

Purangi/Pouiatoa – a forest area of 1000ha in east Taranaki, where kokako have not been heard for many years. Pests have been removed from the area and trapping continues. It is hoped that one day, should Great Barrier become pest free, that similar transfers will take place to the island. If this happens, descendants of the last two kokako who lived there, will be heard singing in the island’s forest.

Lyn Wade, Little Barrier Island Supporters Trust
www.littlebarrierisland.org.nz