The kiwi sanctuaries
Haast Kiwi Sanctuary
In 2000 the Department of Conservation set up five "kiwi sanctuaries", sites for developing better methods of protecting kiwi in the wild. It was recognised that stoats are a key threat and that controlling them is a priority.
The kiwi sanctuaries are in Northland (near Whangarei), the Coromandel (Moehau), Tongariro Forest, and Okarito and Haast on the West Coast of the South Island. The Government's Biodiversity Strategy funding package allocated $10 million over five years to the project, funding that has since been baselined into DOC's budget.
North Island
In the Northland (10,000 ha) and Coromandel (12,000 ha) sanctuaries, stoat trapping has worked very well. By 2005 up to 70 per cent of chicks were surviving to six months old, compared to 11 per cent at unmanaged sites. At this age, they weigh 1kg and are able to defend themselves against stoats. Adult populations (c. 300 at each site in 2000) have been increasing by up to 13 per cent a year. Numbers are expected to reach 1000 at each site within the next decade.
The next step has been to reduce the frequency of trap checks to 12-15 times a year from once a fortnight at both sanctuaries to free up resources to manage an extra 6000 ha of kiwi habitat. While chick survival at the sanctuaries has dropped to 50-60 per cent, populations are still growing rapidly enough to assure good rates of recovery.
Camp kitchen, Haast Kiwi Sanctuary
A different approach to stoat control was trialled in Tongariro Forest, 15,000 ha in the upper Whanganui catchment north of Mt Ruapehu, where there were around 200 birds. An increase in chick survival rates from 12 per cent a year to 36 per cent following a 1080 poison possum control operation in 2000 suggests that good levels of secondary poisoning of stoats occurred. To further increase the chick survival rate, Operation Nest Egg, a captive rearing programme, has been used.
South Island
The two sanctuaries on the West Coast - for the Okarito brown kiwi (rowi) and the Haast tokoeka - have had less success with stoat trapping because of a peculiarity of South Island forest ecology.
Radio tracking Haast tokoeka
In some years beech and rimu produce abnormally high levels of seeds or fruit, which cause rodent populations to explode, which in turn lead to stoat plagues. When rodent numbers crash on running out of food, the stoats get hungry. No amount of trapping can keep them away from young kiwi, DOC scientists have discovered.
At 10,000 ha, the Okarito sanctuary covers the entire range of this species, numbering around 250 individuals. Because of repeated stoat plagues, few or no rowi chicks have survived in the wild in three of the last five years of monitoring. Operation Nest Egg has been used to save some chicks from otherwise certain death. Similar issues apply to the Haast sanctuary (12,000 ha), except that stoat predation is less intense. Chicks have been successfully raised in the wild in four of the last five years at this site.
Other DOC projects
Kiwi are among a range of threatened native species managed at DOC "mainland island projects", sites where several species of pest are controlled simultaneously.
Haast tokoeka
Examples of such projects are Trounson Kauri Park in Northland, northern Te Urewera, Boundary Stream/Maungaharuru in Hawke's Bay, the southern slopes of Mt Ruapehu (Rangataua forest), Pukaha/Mt Bruce, Rotoiti in Nelson Lakes National Park, and in Fiordland near the Milford Track and in the Murchison mountains.
DOC manages a number of predator-free offshore island sanctuaries to protect a range of native species, including little spotted kiwi and North Island brown kiwi.
The kiwi sanctuaries and other projects have focused on priority areas for kiwi conservation, in the knowledge that kiwi numbers on Stewart Island, in much of Fiordland, Northwest Nelson and parts of inland Canterbury are relatively stable because of their remoteness from human habitation and the fact that very wet, cold sites tend to have fewer pests.
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