Mountain poison drop targets pest wallabies

The Dama wallaby, which is often mistaken for a large possum, is too big to have any predators in New Zealand. Photo / Martin Sykes

The Department of Conservation is making its first attempt to eradicate the Dama wallaby species, introduced almost 140 years ago, as the pest threatens native plant species.

About 370 plastic bait stations carrying 20,000 pellets of the cyanide-based pesticide Feratox have this week been laid over 800ha on Rotorua's Mt Ngongotaha.

The mountain has the biggest known isolated population outside Kawau Island in the Hauraki Gulf. Other large isolated populations are in the Te Puke and Pyes Pa area.

The Dama wallaby, one of six known species in the country, was introduced on Kawau and around Lake Okareka in Rotorua by former Governor Sir George Grey in 1870.

The wallabies soon spread around the Bay of Plenty and were first recorded in the Waikato region in the 1950s.

The furry marsupial, weighing up to 8kg and measuring about half a metre tall, feeds on grasses, manuka and kanuka, kamahi, mahoe, hangehange, pigeonwood, supplejack, rangiora and broadleaf.

DoC area manger Nicki Douglas said many people were unaware the pest lived in New Zealand.

"Most of the time they're nocturnal so when people see them when they're driving they ... just look like a big possum."

She said it was hard to tell how many Dama wallabies were in the region. Lake Tarawera residents often complained to the department about the pest in their backyards.

"I've had a few people from the Tarawera community say ... they've never seen so many wallabies as they have in the last two years. So they are definitely increasing in number. [And] they don't really have any predators ... There isn't really anything around that's big enough to kill them."

The DoC operation, conducted with the Bay of Plenty and Waikato regional councils, is part of a three-year project to control the pest and eradicate it from Mt Ngongotaha.

Ms Douglas said eradication of the entire species was a long way off but if it could be kept away from vegetation in forests such as Te Urewera National Park, the Whirinaki Forest Park and the Kaimai Ranges, it would be "good outcome".

DoC is also working to introduce permits for people wanting to take wallabies out of the area. It wants to be able to prosecute people if they do not have a permit.

DoC workers will next week return to the site to count how many wallabies the poison has killed and dispose of the carcasses.

Ms Douglas said they had wanted to keep the stations clear of dead wallabies but a trial of the bait in February and March at Waikite Valley showed the more human activity there was in the area, the less likely the animal was to take the bait. DoC would wait a week before going back to the site.

Feratox, used as an alternative to 1080 in Tasmania for the control of possums and wallabies, carries a risk to humans and animals such as dogs, so farmers in the area are being asked to keep their stock away from the stations.

DAMA WALLABIES

* Introduced from Australia on to Kawau Island and near Rotorua by former New Zealand Governor Sir George Grey in 1870.

* Weigh between 4kg and 8kg.

* Stand about half a metre tall.

* Threaten native plant species.