It is amazing that you can hear the song of the endangered North Island kokako in South Auckland’s Hunua Ranges, less than 50 kms from the central city. A heavy schedule of policy workshops at the Green Party’s Policy Conference at nearby Camp Adair last weekend meant there was no time to go in search of kokako. Green members, however, did get to hear a fascinating talk by two representatives of the Hunua Kokako Recovery Project about how 20 years of hard work has helped increase the numbers of kokako in the ranges.
As an endangered species North Island kokako have a 20 % chance of going extinct in 20 years. In the 1950s there were an estimated 500 kokako in the Hunua Ranges. Habitat loss and predation meant kokako numbers dropped to 80 birds in 1980 and to 21 in the early 1990s with only one female. Female kokako are especially vulnerable to predation by ship rats and possums because they sit on the nest incubating the eggs and brooding the young for around 50 days, while the male feeds the female and the chicks.
The kokako population in the Hunua Ranges has gone from just one breeding pair in 1994 to 55 pairs in 2014, making it one of the six largest populations of North Island kokako.
The increase in the Hunua population is a tribute to the dedication and expertise of Department of Conservation staff, thousands of volunteer hours, iwi involvement and practical support from the Auckland Council and others. It shows what can be achieved when there is good science, a recovery plan is developed and implemented, and there is some funding for pest control (albeit limited).
Ground based predator control over a 1500 ha. core area involving thousands of volunteer hours in steep country baiting bait stations and checking trap lines was crucial in increasing kokako numbers. It allowed birds to breed successfully and their young to fledge. Translocation and successful establishment of individual birds from other North Island kokako populations such as Mapara in the King Country was also important.
Kokako are well known for their hauntingly beautiful song. Kokako from different areas have different calls or dialects. In the Hunua Ranges, DoC set up speakers in several trees to make daily broadcasts of the taped calls of kokako from their original forest areas so that the translocated birds would feel at home and not disappear.
In October 2014, Auckland Council agreed to fund to aerial 1080 control to enable kokako and other birds to breed successfully and recolonise a much larger area of the 18,000 ha. Hunua Ranges Regional Park and water catchment area. This will benefit other species such as Hochstetter’s frog, which already exist in much higher numbers in the Hunua Ranges where pest control occurs. Effective aerial control is also likely to reduce the rate at which possums and rats re-invade the core area subject to ground trapping; freeing up volunteers for other work.
To my mind the Hunua Ranges Kokako project is an example of a successful conservation partnership between DoC and the community. The Department did not have to be completely restructured to implement such partnerships as former Conservation Minister, Nick Smith and the former DoC Director-General have claimed.