Stewart Island Environment Trust

What's special about the Halfmoon Bay wildlife?

Halfmoon Bay has a great diversity of bird life, more similar to our pest-free off shore islands than the rest of Stewart Island where bird life is in rapid decline. This includes large flocks of tui and kereru, bellbirds, little blue penguins, a mainland breeding colony of titi/ sooty shearwater, grey warbler, fantails, kiwi, weka and red crowned kakariki. The only known Stewart Island population of long-tailed bats occurs solely in the Halfmoon Bay area. Many of these individual species, let alone the combination, are distinctive at a national level.

Weka

Tomtit

Stewart Island bird species are suffering the same decline as the rest of New Zealand albeit at a slower rate. Many species have disappeared from the area, for example, mohua/yellowhead, tieke/saddleback, toutouwai/Stewart Island robin. Some such as titipounamu/riflemen have disappeared in the last ten years.

Halfmoon Bay receives upwards of 50,000 visitors each year and many Islanders rely on the swelling eco-tourism industry for their income. The wealth of bird life and unique plant species of Stewart Island are a major draw card for visitors, therefore the health of their populations supports our community's economy.

Stewart Island Robin

Golden Bay

The Halfmoon Bay area is representative of the main forest cover found on Stewart Island lowland temperate rain forest (kamahi, rimu, rata mix). Some unique vegetation is also present. The area has a high number of mistletoe and groves of tree fuchsia are still common.

Spider Orchid

Without some urgent protection, a number of species are likely to disappear completely within the next ten to twenty years. These include muttonbirds/titi and long-tailed bats. Kereru and kaka may also decline to the point where their overall populations are not sustainable long-term. Rata, tree fuchsia and mistletoe are also under threat from possum browse.

Mistletoe

Threats to our wildlife

New Zealand's wildlife has evolved in isolation over the past 80 million years. Native wildlife is threatened by mammalian predators introduced in the late 1800s by pioneering immigrants. Before this, the birds and plants evolved without having a strategy to protect themselves from these new hunters.

Rats

3 species of rats (ship, norway and pacific or kiore) cause considerable damage to the wildlife and are the main focus of the project's pest control efforts. They prey on bird's eggs and chicks in the breeding season. They also eat many of the seeds, berries and fruits that birds rely on to feed themselves.

Possums

Introduced from Australia, the possum browses heavily on the foliage of important native trees. This means that the re-growth of canopy seedlings is inhibited and the forest can not regenerate successfully. This is especially detrimental to iconic species like the Southern Rata, which is dwindling where possums are left to browse.

Feral Cats

Feral cats are strong hunters and pose a big threat to bird species. They can roam a large area and prey especially on ground burrowing birds like the sooty shearwater/titi and little blue penguin.

Deer

White-tailed deer also browse on the forest under-growth. They eat important plant seedlings and saplings. This means that regeneration can not occur and there are fewer trees to replace the canopy.

Stewart Island, unlike the New Zealand mainland, has no mustelids, mice, wild pigs or wild goats, therefore we have a head start on successfully controlling the pests that are here.