North West Island mice infestation eradicated

Issued: 30 Aug 2022

A meticulous long-term mouse eradication program using a helicopter, Black Trakka trapping tunnels and peanut butter on North West Island in the Capricornia Cays National Park has been declared a success.

The eradication program was part of the Queensland Parks and Wildlife Service’s (QPWS) ongoing weed and feral animal pest strategy for islands in the Capricornia Cays National Park.

Ranger Damon Shearer said the island’s populations of wedge-tailed shearwaters and black noddies were initially at risk from feral cats, which had been introduced to the island as domesticated cats decades earlier.

“In the 1990’s we eradicated the population of feral cats, and as the cliché suggests, when the cat is away the mice will play, and the population of common house mice increased,” Ranger Shearer said.

“In May 2020, QPWS and Gidarjil Land and Sea Country Rangers surveyed mouse activity in strategic locations across the island by using the Black Trakka trapping tunnels.

“One hundred and twenty traps were deployed for one night and when rangers examined the traps the next day mouse prints were found in 119 of the traps.

“The trapping tunnels don’t actually trap the mice, rather a bait is placed in the middle of the trap and the mice walk along an ink pad to get to the bait, and as they leave the trap blank pads capture their footprints.”

Ranger Shearer said North West Island is the most significant breeding island for wedge-tailed shearwaters and black noddies on the east coast of Australia.

“Surveys conducted between 2013 and 2016 indicated the numbers of wedge-tailed shearwaters using the Capricornia Cays to breed had declined by approximately forty per cent,” he said.

“The population of common house mice on North West Island posed a significant threat to several seabird rookeries, as they eat the eggs and can also prey on the hatchlings.

“It was extremely important to begin a control program, and in 2020 utilising Reef Trust indirect offset funding through the Reef Joint Field Management Program, we used a helicopter and a bait dispenser to drop rodent bait across the island.

“An eradication program on an island isn’t considered a success until two years of surveys find no signs of the target animal.

“Once again QPWS rangers and Gidarjil Land and Sea Country Rangers used the Black Trakka trapping tunnels to conduct five post-treatment mice surveys from September 2020 to August 2022 and we are thrilled to report there were no signs of mice in those surveys.

“I’m pleased to say the common house mouse has been eradicated on North West Island, but we plan to continue implementing the biosecurity strategy for the Capricornia Cays National Park including the QPWS Be Pest Free program for park visitors.

“This has been a long campaign and a lot of hard work, but it means the wedge-tailed shearwaters and black noddies can breed without introduced predators.

“Visitors to North West Island and other islands in the Capricornia Cays National Park are reminded to be pest free, and to ensure they conduct a thorough check of themselves and their equipment.

“People must check that boats, clothing, footwear and camping gear are free of soil, seeds, parts of plants, ants and insects and their eggs, lizards, toads, rats and mice.

“We want to keep these islands free from pests and weeds and keep them as pristine as possible.”

QPWS acknowledges the funding for the mice eradication was delivered through the Reef Trust in collaboration with Australia Pacific LNG, QGC, and Santos GLNG

Read more information on North West Island.

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