Introduction

Trapping a rat that has invaded predator free Ulva Island/Te Wharawhara, off the coast of Stewart Island/Rakiura, is a high priority for DOC staff.

Rodent prints on tracking card. Photo: Jennifer Ross.
Rodent prints on tracking card

Rodent detecting dog Gadget on Ulva Island. Photo: Matt Jones.
Rodent detecting dog Gadget on Ulva Island

Rat prints were first detected on a tracking card near the Post Office Bay houses as part of a routine tracking card and trap check. Rodent detecting dog Gadget and her handler Sandy King found signs of a rat in two areas after checking the island. 

DOC staff have implemented an incursion response, including activating all traps in the existing network across the island. The work programme is being led by island rat eradication expert Peter McClelland, who spent many years working for DOC, and advice is being received from DOC biosecurity experts around the country.

A team of DOC staff and contractors stationed on the island this and last week have increased trap and tracking tunnel checks from once to twice weekly and installed additional tracking tunnels. 

Ongoing biosecurity work has been supported by the Ulva Island Trust, a group of Stewart Islanders who recognise the importance of this island sanctuary. 

“On average, one rat per year manages to reach Ulva. It’s not surprising, considering it’s very close to Stewart Island,” DOC Ranger Jennifer Ross said. 

DOC will continue with this urgent incursion response until there is certainty no rat is present on Ulva Island.

Background information

Ulva Island

  • Ulva Island/Te Wharawhara (266 ha), located in Paterson Inlet, is a key eco-tourism destination for visitors to Stewart Island. It is visited by 20,000 – 30,000 people per year.
  • It is one of the few predator free open island sanctuaries in New Zealand, meaning no permit is required to visit the island.
  • Rats were initially removed from Ulva Island in 1995 and it is now home to many endangered birds, including South Island saddleback/tīeke, rifleman/tītipounamu, yellowhead/mōhua, Stewart Island robin/toutouwai and the Stewart Island brown kiwi/tokoeka.
  • Most of the island is part of Rakiura National Park and the remaining 7.6 hectares, between Post Office Bay and Sydney Cove, while privately owned, is mostly accessible to the public.

Ulva Island Charitable Trust

  • The Ulva Island Charitable Trust was set up in 1999 by a group of Stewart Islanders to raise money to upgrade walking tracks and facilities on Ulva Island. Now it continues to raise funds, and in conjunction with DOC, works to keep Ulva Island free of introduced pests and predators.

Rat control on Ulva Island

  • A major eradication of Norway rats took place on Ulva Island in 1995.
  • In 2010/11, a rat incursion resulted in an established breeding population on the island. An eradication operation took place over the winter of 2011 and the island was rat-free again in 2012. In 2013, three rats were found in traps and a rat control operation over several months was successful.
Back to top