For their first five years they were funded with NZ$10-million from a government package to support the New Zealand Biodiversity Strategy. Since then, funding for the sanctuaries has been added to the Department of Conservation’s annual budget, and the work has become business-as-usual.
Three of the kiwi sanctuaries are in the North Island, and two are in the South Island. Each protects a different kiwi species or special population. They are:
Why are Kiwi Sanctuaries Needed?
Outside Kiwi Sanctuaries and other managed areas, kiwi populations are declining in most mainland areas and their ranges are shrinking.
Intensively managed sanctuaries and kiwi zones play a key role in our quest to turn around the national decline in kiwi numbers on New Zealand’s mainland. For example, outside their safe borders, Brown Kiwi populations are predicted to halve every 15 years and are in danger of disappearing from the mainland within a human lifetime (75 years).
What the Kiwi Sanctuaries Aim to Achieve
A major part of the work in each sanctuary is controlling stoats, the main reason kiwi populations are declining. Other work is cat and ferret control, and breeding programmes such as the Bank of New Zealand Save the Kiwi Trust’s Operation Nest Egg programme, where eggs are removed and the chicks are hatched and reared in a safe environment before being released back into the forest.
In four of the sanctuaries, the aim is to have more than 20 per cent of chicks that hatch survive to weight more than 1000 grams. Once kiwi chicks reach this size, they can defend themselves against stoats. For the Okarito Rowi, only 16 per cent of hatched chicks need to reach 1000 grams to allow the population to increase – this is because the average lifespan of adult Rowi is longer.
A second part of the Kiwi Sanctuary programme has been looking at whether the work to control stoats to protect kiwi has any effect on other parts of the forest. And it seems it does. When stoat numbers drop, rat numbers rise, and rats kill forest birds, such as fantails. While fantails are relatively common, it is clear that only controlling stoats is not a good strategy in places where threatened birds, such as kokako or mohua live, because they are killed by rats.
Kiwi may also be vulnerable to increased rat numbers because they compete for the same food. This has potential to reduce productivity and increase mortality in chicks and adults and more research is urgently needed.
Progress
During the sanctuaries’ first five years, everything that happened was carefully recorded so that it was possible to establish whether the intensive predator control work was making a difference and helping kiwi chicks survive.
In the three North Island kiwi sanctuaries, progress has been huge. Kiwi numbers have increased rapidly since the intensive trapping of stoats began and the populations are expected to increase four-to-five times up to 2015. This provides a good safety net that allows new management techniques to be tried which may help reduce costs. A major cause of concern remains the number of adult kiwi killed by roaming dogs.
However, breeding success in the two South Island kiwi sanctuaries continues to be low, despite stoat trapping, and it is clear these populations are more complex to manage. The dynamic between seeding trees, rodents and stoats, and the low number of eggs laid by breeding pairs means current management techniques are only just effective in reversing declines.
The results from all five sanctuaries make it clear that one management approach cannot be used for all areas when it comes to kiwi conservation. Management needs to be tailored to each kiwi area. For the South Island sanctuaries, Operation Nest Egg is proving to be a life-saver while researchers try to better understand the management issues and identify the broader range of tools needed to achieve breeding success.
Other Kiwi Zones
As well as its work in the Kiwi Sanctuaries, the Department of Conservation is doing kiwi recovery work in Egmont, Te Urewera and Fiordland national parks.
Significant contributions are also made by community groups and commercial sponsors – in particular the Bank of New Zealand Save the Kiwi Trust. Fifty community-led kiwi projects are underway around the country, mainly in the North Island.
To read about some of these groups, click here.