A kiwi is any of the species of small flightless birds endemic to New Zealand of the genus Apteryx (the only genus in family Apterygidae). There are currently six recognized species of kiwi:
- Great Spotted Kiwi, Apteryx haastii, distributed through the more mountainous parts of northwest Nelson, the northern West Coast, and the Southern Alps.
- Little Spotted Kiwi, Apteryx owenii, on Kapiti Island.
- The North Island Brown Kiwi, Apteryx mantelli, is widespread in the northern two-thirds of the North Island.
- The Rowi, also known as the Okarito Brown Kiwi or Apteryx rowi, limited to a small area on the west coast of the South Island of New Zealand.
- The Southern Tokoeka, Apteryx australis australis, relatively common species of kiwi known from southwest South Island (Fiordland) that occurs at most elevations.
- The Haast Tokoeka, Apteryx, only occurs in a restricted area in South Island’s Haast Range at an altitude of 1,500 m.
Kiwi are shy nocturnal creatures with a highly developed sense of smell and, most unusual in a bird, nostrils at the end of their long bill. They feed by thrusting the bill into the ground in search of worms, insects, and other invertebrates; they also take fruit and, if the opportunity arises, small crayfish, amphibians and eels.
After an initial meeting during mating season (March to June) kiwi usually live as monogamous couples. The pair will meet in the nesting burrow every few days and call to each other at night. These relationships have been known to last for up to 20 years. Kiwi eggs can weigh up to one quarter the size of the female. Usually only one egg is laid. Although the kiwi is about the size of a domestic chicken, it is able to lay eggs that are up to ten times larger than a chicken’s egg.
Their adaptation to a terrestrial life is extensive. Like all ratites they have no keel on the breastbone to anchor wing muscles, and barely any wings either. The vestiges are so small that they are invisible under the kiwi’s bristly, hair-like, two-branched feathers. While birds generally have hollow bones to save weight and make flight practicable, kiwi have marrow, in the style of mammals.
The kiwi is also a national symbol for New Zealand.