Rangitoto & Motutapu islands restoration project

The sucessful removal of all pest mammals from Rangitoto and Motutapu islands is now complete. This is a significant milestone in Auckland Conservancy's ambitious and exciting programme to restore these iconic islands in the Hauraki Gulf Marine Park.

The restoration of these islands will protect the world's largest pohutukawa forest, and will provide a 3,800ha environment that can now support some of New Zealand's most loved wildlife, including takahe and saddleback (tieke), which were released on Motutapu at an event on 27 August 2011 marking the official pest-free status of the islands.

What did the pest removal project involve?

The project removed the seven remaining mammalian pests - feral cats, rabbits, stoats, hedgehogs, Norway rats, ship rats and mice - from Rangitoto and Motutapu islands. This built on the successful removal of possums and wallabies from the islands in the 1990s, and the reforestation of parts of Motutapu.

Motutapu Island with Rangitoto Island
in the background

This was a flagship project, due to its size, complexity and proximity to Auckland city. It was 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.

For example, in 1993 Tiritiri Matangi Island was successfully cleared of mammalian pests using the same method, and is now one of our most popular open sanctuaries, attracting around 35,000 people a year to view endangered wildlife such as takahe, stitchbird (hihi), saddleback (tieke), kakariki and kokako.

How were pests removed?

The most efficient way to eliminate all of these pests was through a combination of poisoning (particularly for rodents) and trapping.

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.

Mouse

Following the aerial bait drops, a large team of dedicated 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.

Pest removal project results

The restoration project has been extremely sucessful with Rangitoto and Motutapu declared officially pest free on 27 August 2011.

Stoat

What happens next?

We are now into the next stage of the restoration project which involves re-establishing native species on Rangitoto and Motutapu.

Since the aerial bait drops in winter 2009 native species previously not seen on the islands for many years have returned, including kakariki and bellbirds. Tui numbers have soared and a number of other small bird species have quickly increased in number.

Now we can transfer native species to the islands that are unable to reach them under their own steam. The first of these transfers happened in August 2011, with takahe and saddleback (tieke) released on Motutapu Island.

What will this mean for visitors?

There are no restrictions on visitors to Rangitoto and Motutapu.

The main impact on visitors will be the increasing noise of bird song from the native birds that are no longer being killed by the rats, cats and stoats that were so recently on the islands!

However, a network of traps will remain on Rangitoto and Motutapu to help prevent stowaway pests establishing new populations on the islands. If you should happen to come across any of our well-marked traps on the islands, please leave them as they are.

How can you help look after these islands?

The successful eradication creates the largest pest-free island sanctuary (3,842ha) 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.

Planting on Motutapu

We need your help to keep Rangitoto and Motutapu pest free. All visitors need to be vigilant about any "stowaways" and report any sightings of pests or inappropriate behaviour on the islands.

Prevention is better than cure, so we are asking visitors to reduce the risk of pests reinvading. Simple steps you can take include:

• Checking your boat, bags and equipment for rats, mice, Argentine ants, rainbow skinks, soil and seeds before you leave the mainland.
• Check you gear, especially footwear, for soil and seeds.
• If you are staying overnight, check your tent, bedding and camping gear thoroughly.
• Avoid open bags - use bags you can securely ziop up.
• 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.

For more information on what you can do to help protect conservation islands in the Hauraki Gulf Marine Park, visit www.treasureislands.co.nz.

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