A Winter of Mouse Eradications

This winter has seen New Zealand teams busy with mouse eradications across the country. In the Hauraki Gulf the University of Auckland and Auckland Council teamed up to eradicate introduced house mice (Mus musculus) from two neighbouring small islands; Moturekareka and Motuketekete, with the last bait being applied last weekend. At around 25 hectares each the islands are small, but monitoring work by MSc student Kat Reynolds found mice were abundant. Although not as bad as rats or larger introduced mammals, the presence of mice alone is still devastating on islands, with impacts on the plants and invertebrates they eat, and birds they compete with for food. The eradication of mice on both islands was led by Jamie MacKay from Wildlands and undertaken using a 25 metre spaced grid of bait stations across the island, ensuring every mouse had access to bait. Teams equipped with GPS access every station and ensure bait is available, or where access is impossible (e.g. cliffs) hand-spread bait. The successful confirmation of eradication of mice in the future will add two more pest-free islands to the Hauraki Gulf Marine Park.

Moturekareka Island (Photo: John Robinson)

Each island also has a unique hisstory. Moturekareka is currently a Department of Conservation owned island, and previously had a resident hermit who purchased and wrecked an entire boat, the Rewa, to make a harbour in 1930. A second hermit, “Snow” Harris, was more recently resident. Motuketekete is privately owned, and until recently had wild guinea pigs running across it. Grey-faced petrel were found breeding on both islands during the mouse eradications. Elsewhere in the country, eradication of mice occurred on Maud Island, and planning continues for the Antipodes Island mouse eradication. Meanwhile on Adele Island, from which mice were eradicated in 2007, South Island saddleback were recently reintroduced, having been rescued many decades earlier from Big South Cape Island.

"Snow" Harris: 1904-1978
“Snow” Harris: 1904-1978

Changing Planet

Conservation biologist Dr. James Russell works throughout the world on remote islands and other sites to provide conservation solutions by applying a combination of scientific methods. Follow James on National Geographic voices for regular updates on his own work or other exciting developments in island conservation.