Overview
Birds were the dominant land vertebrates in New Zealand before human contact. The first Polynesian explorers encountered a world quite different to the New Zealand we know, populated by many large, flightless species (including moa), as well as a wide range of waterfowl, rails, tiny wrens and other birds. Many of these species became extinct before European contact due to the combined pressures of hunting, habitat reduction, and the depredations of the Pacific rat (kiore) introduced by Māori.
Further species became extinct after European colonisation, mainly due to introductions of additional predators (including feral cats, feral pigs, ship rats, Norway rats, stoats, ferrets and brushtail possums) and increased habitat loss. However, development of farmland created new habitats for bird species arriving and colonising from Australia, along with those deliberately introduced from other parts of the world. As a result, the bird fauna of modern New Zealand is very different from that of 1000 years ago.
There were estimated to be 209 breeding bird species in New Zealand at first human contact; 35 of these became extinct following Polynesian (Māori) settlement, and a further 16 since 1800 AD. Seventeen species have colonised naturally during this time, including four before European contact (Australasian bittern, Australasian harrier, pukeko, and pied stilt). Many dozens of bird species were introduced from Europe, North America, Australia and Asia, and about 37 of these have established wild populations. These include most of the familiar species of New Zealand cities, towns and farmland.
The modern New Zealand bird fauna is comprised of about 206 breeding species, of which 94 (46%) are endemic (i.e. found only in New Zealand), another 76 are native, but also occur elsewhere (37%), and 37 (18%) are introduced. A further 26 species are non-breeding migrants, and 133 species have been recorded as vagrants.
Many bird species have more than one subspecies within New Zealand, resulting in a breeding bird fauna of about 252 named forms. Of these 78 (31%) are recognised as threatened, 93 (37%) are at risk, 36 (14%) are not threatened, 8 are colonising, and 37 are introduced. The main threat to surviving native birds is predation by introduced mammals, with other detrimental factors including changes in land-use, changes in oceanic productivity possibly driven by climate change, and fisheries interactions.