Mainland Populations

This will provide confidence none will become extinct in the medium term.

To achieve these goals, a lot of research has been done on the birds’ preferred habitat and what threatens their survival.

The findings have allowed scientists to develop techniques to create safe zones, and these are now being adapted and applied to larger areas.

Safe zones

Five safe zones are the kiwi sanctuaries managed by the Department of Conservation to protect three brown kiwi taxa, rowi and the Haast tokoeka. The kiwi sanctuaries have provided opportunities for valuable research on kiwi ecology, and enabled new kiwi management technologies to be developed.

Efforts by the Department, community groups and iwi are also creating safe ‘islands’ on the mainland. In some cases, such as Nelson Lakes National Park, kiwi are being reintroduced to areas where their calls have not been heard for many years. In others, such as at Lake Waikaremoana, the work is allowing existing kiwi populations to increase.

Securing populations

Two brown kiwi taxa have already reached the goal of having 500 breeding pairs in a secure managed population - the Northland and western brown kiwi – and others are on the way. However, more work is needed to provide secure populations of a number of taxa, including great spotted kiwi and Fiordland tokoeka.

Growing small populations

A particular challenge is increasing the size of New Zealand’s two most rare kiwi – rowi and the Haast tokoeka.

Because each taxon is only found in a small area, and populations are very small, they are at risk from random threats, such as fire or a localised stoat outbreak.

The risk is made worse because both taxa have low breeding output (fecundity). For example, research has shown that about 40% of potential rowi breeders don’t contribute to the population. Just why is not yet understood, but until we learn the answer, BNZ Operation Nest Egg™ and intense predator control are being used to help increase the population.

As well, new populations of both species are being established.

Establishing new kiwi populations

Creating new populations is a good insurance policy for kiwi species with low population numbers.  One example is the little spotted kiwi.

Since about 1920, little spotted kiwi have established a thriving population, but almost exclusively on Kapiti Island. That leaves the species vulnerable to random disasters, such as stoats reaching the island.  

Some birds from Kapiti have therefore been transferred to other safe places to establish new populations, including Tiritiri Matangi Island in the Hauraki Gulf, and the Karori Wildlife Sanctuary in Wellington City.  These transfers mean the little spotted kiwi population is now regarded as safe, but there may be some issues around its genetic diversity.