Department of Conservation staff who’ve been hunting a rat detected on Rangitoto Island in the Hauraki Gulf Marine Park are confident the rat is dead after eating a lethal dose of rat poison.
“We haven’t found its body but we’re confident the rat is dead as it’s eaten six pellets of poison bait and two pellets are a lethal dose,” says DOC Auckland Area manager Brett Butland.
“It’s been more than three weeks since we found any rat tracks on Rangitoto, further evidence the rat has died after eating enough poison to kill three rats, ” says Brett Butland.
DOC launched a major search and trapping operation six weeks ago when a ranger and his specially trained dog found rat tracks in a routine check of rodent detecting tunnels near the Rangitoto wharf. The tunnels ring Rangitoto and Motutapu as part of the biosecurity measures DOC has to protect the pest free islands it manages in the Hauraki Gulf Marine Park.
DOC has been treating Rangitoto and Motutapu as pest free after conducting an eradication programme to remove rats, mice, stoats, feral cats, hedgehogs and rabbits from the islands in 2009. Possums and wallabies were removed in the 1990s.
The pest eradication will enable the islands to become one of the country’s largest sanctuaries for endangered wildlife - like takahe, tïeke, kiwi, kaka and tuatara - in the heart of Auckland. It also protects native plants including the world’s largest pohutukawa forest on Rangitoto.
“DOC rangers, with help from the Auckland Council, have been working hard to catch the rat,” says Brett Butland. “We’ve been using rodent detecting dogs and have set 231 traps.”
“We’ve deployed a variety of traps and used a wide range of baits including cheese, peanut butter, almond butter, smoked fish, fish oil soaked dog biscuits and chocolate buttons.”
“Unfortunately the rat refused to enter any of the traps. We suspect it may have survived an encounter with a trap in the past and become trap shy.”
“It did however regularly enter tracking tunnels and eat food baits which led us to place pellets of the rat poison in a number of tunnels.”
“The rat ate six pellets of poison bait in a detection tunnel leaving just a few crumbs behind. That’s a triple fatal dose. We’ll continue working to protect Rangitoto and Motutapu from pests but the search and trapping operation targeting this particular rat is being wound up.”
“It’s disappointing the rat got onto the island but the reality is that pest incursions like this will occur due to the number of vessels that visit Rangitoto and Motutapu.”
“The fact we detected the rat and are confident we’ve poisoned it shows our biosecurity measures and surveillance systems are effective.”
“We want people to visit and enjoy these islands but the public needs to be aware of the risk of unwanted pests accompanying them onto these sanctuaries for rare wildlife and plants,” says Brett Butland.