New Zealand’s birds can be categorised as endemic, native or introduced.
Most of New Zealand’s native birds are endemic – they are found nowhere else. They evolved into new species in New Zealand, and are of special interest to birdwatchers from overseas. There are endemic species, genera, families and orders – the latter evolved in isolation for so long that they are only distantly related to groups on other land masses.
Endemics include a number of forest birds such as kiwi, saddlebacks and riflemen, shorebirds such as the wrybill, native parrots, various Chatham Island species and subspecies, and many seabirds.
Native birds are those that naturally occur in New Zealand. In addition to endemics, they include species that also exist in other countries. Native birds that are also found elsewhere, in the same or a closely related form, include the white heron, cattle egret, kingfisher, pūkeko, harrier, morepork, silvereye, two gulls and some ducks.
Northern and southern forms
Rising sea levels at the end of the last ice age separated the North and South island bird populations. Regional subspecies or species developed, notably of kōkako, but also of the robin, tomtit and the piopio (now extinct). The yellowhead and brown creeper are found only in the South Island, while the whitehead, in the same genus, occurs only in the north. The kea (a mountain parrot) lives only in the South Island, which is also the northern limit of some penguins. Wrybills and black-fronted terns breed in the South Island, but some spend winter in the North Island.
The Chatham Islands, subtropical Kermadec Islands and subantarctic islands also have species or subspecies related to but distinct from the mainland species.
The native pūkeko is an example of a species that probably came to New Zealand about 1,000 years ago. It is found worldwide, and is known elsewhere as the purple gallinule. It evolved from the same ancestral species that evolved in New Zealand as the takahē.
Among the birds that have reached New Zealand from other countries during the 20th century are the white-faced heron, welcome swallow and spur-winged plover. Once they establish breeding populations, these self-introduced birds are considered natives.
Thirty-nine deliberately introduced species have formed self-sustaining wild populations. They are not considered native. Most come from Europe, and others from Asia, Australia and North America. They were brought in for sentimental reasons (sparrows, blackbirds and thrushes), or for sport (quail, pheasants and Canada geese), or to control insect pests (magpies, mynas).