As a land without terrestrial mammals of any kind, New Zealand was, until the arrival of the first humans, inhabited by an extraordinarily diverse range of specialised birds. The ecological niches occupied by mammals as different as rodents, kangaroos and moles, were filled by reptiles, insects, or birds.

When humans arrived in New Zealand sometime between 800 and 1300, this unique and unusual ecology became endangered. Several species were hunted to extinction, most notably the moa and harpagornis. The most damage however was caused by the other animals that humans brought with them, particularly rats (the Polynesian Rat or kiore imported by Maori and the Brown Rat and Black Rat subsequently introduced by Europeans), but also dogs, cats, stoats, weasels, hedgehogs, and Australian possums. The flightless birds were in particular danger. Consequently many bird species became extinct, and others remain critically endangered. Several species are now confined only to offshore islands, or to fenced "mainland islands" from which predators have been eliminated. Consequently New Zealand is today a world leader in the techniques required to bring severely endangered species back from the brink of extinction.

Introduced birds

Self introduced birds

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