Pests in the Auckland Islands

The diverse invertebrates of Auckland Island are a key prey species for mice, which after invading the islands during settlement attempts in the mid-19th century can still be found on Auckland Island. As well as insects and arthropods, mice eat bird eggs and strip flower seeds. Pigs and cats haunt the rata forest and tussocks of Auckland Is, preying on albatross, penguins and small birds. Pigs dig up megaherbs for their roots and now these charismatic plants are holding on only in small pockets on the rocky outcrops of Auckland Is, in the few places the intrepid pigs can’t reach.

rata without understorey

Rata forest on Auckland Island lacks the thick groundcovers seen on Enderby Island

cliff vegetation

Megaherbs take refuge on the cliffs of Auckland Island

Along with the pigs, other animals were introduced during colonisation attempts and as food sources for castaways during the 19th century. These included cattle, goats, wekas, sheep and rabbits. Goats, wekas and sheep all died out or were removed by the late 20th century, but the cattle and rabbits remained, notably on Enderby Island. The isolation of the island resulted in the animals developing distinct characteristics that agronomists in New Zealand were keen to preserve ahead of the planned pest eradication program on Enderby Island in 1993 (see info in the links above). In 1990 a team of hunters were despatched to Enderby Island by the NZ government to eradicate the cattle, and all animals found were shot. It was thought that the cattle were eradicated until 1992, when a female and calf were found. These animals were returned to NZ for attempts at a breeding program. The rabbits of Enderby Is were considered a rare breed and 49 individuals were removed from the island in 1992.

enderby heath boardwalk

Tussocks, herbs and moss have all benfited from the removal of cattle and rabbits from Enderby Island

In 1993 the NZ government undertook and island-wide baiting program on Enderby Island, and followed this with intensive hunting with dogs, spotlighting and trapping. Subsequent surveys found that both rabbits and mice had been successfully eradicated. The successful pest eradication became the bench-mark for future island-wide eradication programs in the Subantarctic. The NZ government followed on this success with the eradication of Norway rats from Campbell Island in 2001, with data, methods and expertise from these programs going on to inform and support the successful Macquarie Island Pest Eradication Program in 2011-14.