The Rangitoto and Motutapu islands restoration project began in 2009 with the aim to remove the seven remaining animal pests from the islands.

This built on the successful removal of possums and wallabies from the islands in the 1990s, and the reforestation of parts of Motutapu.

Due to its size, complexity and proximity to Auckland city this is a flagship project. It is the next step in a long line of pest eradication programmes and their associated restoration programmes that have been happening in the Hauraki Gulf Marine Park since the 1990s, such as the restoration of Tiritiri Matangi Island.

What's happening now?
How were pests removed?
How can you help look after these islands?

What's happening now?

With the pest eradication completed and the island officially declared pest free in August 2011, the next stage of the restoration project has begun - re-establishing native species on Rangitoto and Motutapu, and making sure the islands stay pest free.

Saddleback/tieke on Motutapu Island

Native animals

Since the aerial bait drops in winter 2009 native species previously not seen on the islands for many years have returned on their own, including NZ parakeet/kakariki and bellbird/korimako.

Tui numbers have soared and a number of other small bird species are breeding up a storm and have quickly increased in number.

Transfers of other native animals unable to reach Rangitoto and Motutapu under their own steam are also underway:

• August 2011 - takahe released on Motutapu and saddleback/tieke released on Rangitoto and Motutapu islands
• November 2011 - freshwater species (red-finned bully and native crayfish/koura) released into Home Bay Stream on Motutapu Island
• February 2012 - shore plover released on Motutapu Island
• June 2012 - more saddleback/tieke and whitehead/popokatea released on Motutapu Island
• October 2012 - Coromandel brown kiwi released on Motutapu Island

Native plants      

Rare and endangered plant species have been introduced to the Motutapu Nursery and will be planted out once further weed control has been done to prepare sites. Plants include:

Euphorbia glauca, an endangered plant to be planted on the islands

• Euphorbia glauca - currently only found on two island locations and thought to be extinct from the Auckland region
• Ficinia spiralis (pingao)
• Poa billardierei

Regular surveys to monitor the survival of Daucus glochidiatus (native carrot) which grows on Rangitoto Island show that this plant is thriving since pests have been removed.

Ongoing surveillance and monitoring

Of all the animal pests, because of their swimming ability, stoats and rodents are most likely to make their way back to Rangitoto and Motutapu.

Much planning and action is still focused on ongoing surveillance for pests (including the regular use of detection dogs) and educating visitor about how to help keep the islands pest free. 

An active trap network and monitoring regime is still in place with a Ranger employed to monitor traps and tracking tunnels. Unused trap lines and closed traps have been retained so they can quickly be set and re-baited should a rodent or stoat be detected.

Tremendous support

Contributing hugely to the restoration programme is the Motutapu Restoration Trust. The Trust and their many volunteers undertake tasks such as bird and reptile monitoring, plant restoration and weed removal.

back to top

How were pests removed?

Release of Coromandel brown kiwi on Motutapu Island

The most efficient way to eliminate the seven remianing animal pests - feral cats, rabbits, stoats, hedgehogs, Norway rats, ship rats and mice - on Rangitoto and Motutapu islands was through a combination of poisoning (particularly for rodents) and trapping.

Aerial bait drops

The eradication began with three very successful aerial applications of rodent bait containing brodifacoum between June and August 2009. Brodifacoum was identified as the most effective poison for eradicating rodents in this situation.

The excellent coverage achieved, coupled with near perfect weather conditions during and after each aerial bait drop meant that rodents on Motutapu and Rangitoto were exposed to bait right through the harshest period of the winter.

Trapping

Two solid years of energetic work on the ground followed the bait drops. A large team of dedicated DOC staff and contractors searched out any surviving pests using a combination of methods including a network of over 2000 traps, night searches using powerful spotlights, and the use of specialist dogs individually trained to detect either rodents, hedgehogs, rabbits, cats or stoats.

Results!

In June 2011 the last of the animal pests, the seemingly benign hedgehog, was bid farewell.

Throughout mid 2011, stoat and rodent dogs and their handlers were used to thoroughly search all likely habitat on both islands for any remaining pests. None were detected.

Rangitoto and Motutapu were officially declared officially pest free on 27 August 2011. The future does look bright; the dream of these islands being animal pest free has been realised.

Motutapu Island with Rangitoto Island in the background

 How can you help look after these islands?

The successful eradication creates the largest pest-free island sanctuary (3,842 ha) in the Hauraki Gulf Marine Park, and one of the largest pest-free islands in New Zealand, less than 30 minutes via ferry from downtown Auckland City. There are no restrictions on visiting these islands.

You can help ensure the long term success of keeping pests off this island and preventing reinvasion. Before you leave the mainland or travel between islands in the Hauraki Gulf, please:

• Check your boat or kayak and gear for rats and mice, Argentine ants, rainbow skinks, soil and seeds.  
• Clean footwear, clothing and gear of soil and and seeds – weeds are a problem on the island.
• Pack luggage and all food you are bringing to the island in rodent-proof containers – no open bags/boxes/containers or plastic bags please.
• If you are staying overnight, check your tent, bedding and camping gear thoroughly.
• Leave your dog or other domestic pets at home – dogs pose a risk to the native species on this island.
• Recreational boat owners should look for rodent signs and ants before departure and owners of large boats should keep traps or rodent bait on board.
• If you come across any of our well-marked traps on the islands, please leave them as they are.
• View the biosecurity information for visitors to the Hauraki Gulf (PDF, 389 K)

 Read more about Treasure Islands

back to top