This follows a much earlier episode, in 1894, when the Department of Lands and Survey appointed Richard Henry as curator of the island, which was stocked with species such as kākāpō and kiwi that were threatened by mustelids on the mainland.

[3] The island is an important sanctuary, not only because it has never been colonised by possums, but also because it contains much ecological diversity in habitats ranging from wetlands to forests to alpine areas, with the highest mountains on the island reaching around 1,000 m. The most widespread forest type on the island is beech-broadleaved forest, while the alpine areas comprise mainly tussock, but also wetlands and tarns.

Over 400 indigenous species have been recorded on the island, which is considerably more than on the surrounding mainland.

[5] The only introduced mammals on the island are stoats, red deer and mice.

[7] Many other native bird species can be found on the island, including karearea (New Zealand falcon), kaka, kea, and kiwi.