Operation Ark, a flagship multi-species protection programme led by DOC from 2004 to 2010, provided valuable lessons for the future of pest control and species management for mainland sites.


The programme was launched in response to devastating rat and stoat plagues in South Island beech forests that caused the rapid decline of species such as mohua and parakeets. The primary purpose of Operation Ark was to ensure the long-term survival and sustainability of key native species on the mainland.

In this section


Management and associated monitoring was undertaken to protect four key species from possums, stoats and rats and to control pest plagues that follow beech seed masting. The programme refined and expanded pest control techniques through two major rat plagues in 2006 and 2009.

Successful gains for the four species after six years were:

Whio (blue duck) Populations were sustained at three sites (Oparara/Ugly, Wangapeka/Fyfe and Clinton/Arthur/Cleddau), with increases most marked where there was egg removal, captive rearing and re-introductions of young birds.

Orange-Fronted Parakeets (kākāriki karaka) Populations in the Hawdon/Poulter and South Hurunui were stabilised and protected off-shore island populations established.

Mohua (yellowheads) Populations were stabilised or increased at all sites (Landsborough, Dart/Caples, Blue Mountains and Catlins) and re-introductions to the Eglinton Valley and South Hurunui undertaken.

Pekapeka (long-tailed and short-tailed bats) Intensive monitoring showed that populations in the Eglinton Valley have stabilised or are increasing after the decline experienced when they were unprotected from rats in 2001-02.

Lessons learnt

The findings from Operation Ark have provided valuable input into the species management of other mainland sites around the country. The findings include:

  • Rat trapping was found to be ineffective in protecting threatened species in plague situations
  • Aerially broadcast 1080 poison and variable-toxin bait stations were shown to reduce rat numbers sufficiently to protect bird and bat populations
  • Stoat trapping lines along river valley floors and in networks were successful at keeping stoat numbers down and enabling protected species recovery
  • Breeding and translocation of whio was tested successfully at a number of sites
  • The relationship between climate, beech seed and rat and stoat plagues is also now much better understood.

End of the programme and future funding

In June 2010, the Operation Ark programme came to an end, and the funding is now provided directly to the sites, or placed in a new contingency pool overseen by DOC’s South Island Pest Response Advisory Group (SIPRAG).

SIPRAG provides contingency funding in rat and stoat plague years, as well as using annually allocated aerial 1080 money to achieve greater success through cyclical multi-pest control.

The research programme to understand the ecology of parakeets and mohua; their interaction with pest species; and to improve the effectiveness of aerial 1080 for rat and stoat control continues to support SIPRAG.

All Operation Ark and aerial 1080 possum control sites have been reviewed and the species and ecosystem priorities re-ranked, as part of the optimisation process within the National Heritage Management System (NHMS).

An Operation Ark: Three year progress report was published in October 2007.

The benefits of a coordinated approach to species management, including the lessons learnt from the Operation Ark programme will continue to enhance the management of sustainable populations of key species for years to come.

Map of Operation Ark sites

This map shows the location of the Operation Ark sites and the species protected at those sites. 

Map showing location of Operation Ark sites and the species protected at those sites.

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