The Haast Tokoeka Sanctuary protects Haast tokoeka.
The Sanctuary lies on the seaward toe of the Haast Range in South Westland, about 25 kilometres south of Haast township. Its 11,000 hectares rise from sea level to 1600 metres, with the upper alpine area frequently covered in snow.
The Sanctuary covers at least 85% of the area where Haast tokoeka are known to live. With an estimated population (2012) of about about 402 birds, Haast tokoeka are one of New Zealand’s most threatened native species—they are ranked as ‘threatened: nationally critical’. Two issues are predation by stoats and the birds’ low breeding rate—pairs lay one or fewer eggs each year.
Operation Nest Egg
Population modelling shows 40% of chicks need to survive to sustain the Haast tokoeka population. However, without management intervention, fewer than 10% of Haast tokoeka chicks survive to adulthood. The Department of Conservation (DOC) therefore carries out intensive stoat control inside the Sanctuary, and, since 2007, has used Operation Nest Egg as the main management technique to boost chick survival. Operation Nest Egg was first trialled during the 2003/04 breeding season.
It is expected Operation Nest Egg will enable the population to grow by 5%–10% each year over the next 5-to-10 years, and help to reach the long-term recovery goal of 600 birds by 2018.
Boosting the population long term
While Operation Nest Egg is successful in boosting the Haast tokoeka population, researchers are looking for less labour-intensive and invasive methods. Part of the answer may be to reduce competition for their food, as it is likely that better fed birds will produce more eggs. Some birds (10% of the population) have been transferred to habitat-rich pest-free kohanga areas, including Coal Island and Orokonui Sanctuary, to see if breeding productivity and survival increases. As well, the kiwi’s main food competitors—rats and possums—are being controlled within the Sanctuary.