A 50/50 deal
The owners of Ahuahu Great Mercury Island, Sir Michael Fay and David Richwhite, worked with DOC to get rid of pests. The owners had the money and the motivation so they gave $750,000 and the use of the island’s facilities, boats, and helicopter. This matched the amount from DOC. It was a 50/50 deal of a kind that DOC had not carried out before. It became a successful partnership that achieved amazing results.
How were rats and feral cats removed?
Eradication of rats and cats from Ahuahu Great Mercury took place over winter and spring 2014. The six-month project was tricky. DOC provided specialist skills in species management, island pest eradication and island biosecurity.
Helicopters applied rat poison pellets over the island. The pilots used GPS to put bait in the exact places. The helicopters had special buckets for the bait drops.
All stock was taken away from the island beforehand. They did not return for several months after the poisoning was complete.
Due to the island’s terrain, it was a hard task to make sure the island was pest free. Conservation dogs found the last remaining cats on the island. They also kept checking for rats and mice.
The final air operation to remove the last of the rats and feral cats was on 11 August 2014.
How has pest eradication helped?
The project showed success straight away. For example, in 2012 there was only one grey-faced petrel chick and in 2014 there were 20.
Removing rats and feral cats from Ahuahu Great Mercury has made the island safer for native birds, such as:
- kākā
- kākāriki
- little blue penguins/kororā
- New Zealand dotterel/tūturiwhatu
- petrels/tāiko
- other sea birds.
Taking these pests away has helped
- tuatara
- native geckos
- skinks
- Mercury Island tusked wētā
- other insects
- 50 species of native land snails.
DOC can now move endangered native wildlife onto Ahuahu.
The pest eradication project was important because the islands near Ahuahu Great Mercury are pest free and close enough for pests to swim to them.
- Ahuahu-Great Mercury Island declared pest free – media release 13 May 2016.
- Read more about the Mercury Island tusked wētā - article by DOC ranger Rob Chappell.
