Mainland Islands

Forest and Bird, Issue 293, 1 August 1999, Page 16

Mainland Islands

ward reserve to create a ‘mainland island’ has been taken up by Auckland regional park services. The idea is to protect an area from invasion by pests such as rats, ferrets and cats, so that birds (and nature generally) can live in a predator-free environment. Borrowing the concept from the Department of Conservation, the Auckland Regional Council has tried to eradicate pests from 60 hectares of coastal forest on the south headland of Wenderholm Regional Park, north of Auckland. Trapping possums and rats has helped the forest recover. Native pigeons benefited first, so that flocks of the birds may now be seen over the reserve. A night walk with a torch reveals hundreds of insects moving about the forest litter, where once only rats ran. Young trees are rising from the forest floor. This year North Island bush robin were released within sight of State Highway One. The birds were surplus from stocks which built up to maximum carrying capacity in just five years on the open sanctuary of Tiritiri Matangi Island, which is free of predators. Now the Tawharanui Regional Park of nearly 600 hectares, and the 376-hectare Shakespear Regional Park, have been marked out as potential mainland islands. The Shakespear property at the end of the Whangaparaoa Peninsula is so close to the open bird sanctury of Tiritiri Matangi offshore that bellbirds have recolonised the mainland here from the island. Projecting out to sea on a peninsula north of Kawau Island, Tawharanui is an exposed farm park with substantial areas of coastal forest, and good wetlands. Trapping of pests is already underway to protect its coastal areas where variable oystercatcher and endangered New Zealand dotterel breed. Hundreds of bait stations are being set up over the farm park, and trap-lines are proposed to target stoats, ferrets and cats. A predator fence across three kilometres of inland boundary has also been discussed, though the possibility of reinvasion remains because of the broad sand beaches and tidal rock platforms which would allow predators to bypass it at low tide. ARC Parks chairman, Bill Burrill, talks of wanting kiwi, weka, robins and whitehead released here, and for an attempt to be made to re-establish bellbirds which have long been extinct in the north. The re-estab-lishment of mainland petrel colonies is another possibility. The council’s interest in mainland islands is encouraging for conservation because several of its parks are on peninsulas. By securing them against invasion by predators, peninsulas are particularly suited to becoming mainland islands. T= technique of securing the boundaries of a land-