The population is estimated at over 20,000, distributed through the more mountainous parts of northwest Nelson, the northern West Coast, and the Southern Alps / Kā Tiritiri o te Moana of the South Island. The female lays one egg a year, which both parents incubate. It has grey-brown plumage with lighter bands. The largest species, standing about 45 cm (18 in) tall, with females weighing about 3.3 kg (7.3 lb) and males about 2.4 kg (5.3 lb). There are five known species of kiwi, with a number of subspecies. Research published in 2013 on an extinct genus, Proapteryx, known from the Miocene deposits of the Saint Bathans Fauna, found that it was smaller and probably capable of flight, supporting the hypothesis that the ancestor of the kiwi reached New Zealand independently from moas, which were already large and flightless by the time kiwi appeared. Taxonomy and systematicsĪlthough it was long presumed that the kiwi was closely related to the other New Zealand ratites, the moa, recent DNA studies have identified its closest relative as the extinct elephant bird of Madagascar, and among extant ratites, the kiwi is more closely related to the emu and the cassowaries than to the moa.
The genus name Apteryx is derived from Ancient Greek 'without wing': a- ( ἀ-), 'without' or 'not' ptéryx ( πτέρυξ), 'wing'. The plural is either the anglicised kiwis or, consistent with the Māori language, appearing as kiwi without an ‑s. The word is usually uncapitalised when used for the birds. So when the first Polynesian settlers arrived, they may have applied the word kiwi to the new-found bird. With its long decurved bill and brown body, the curlew resembles the kiwi. However, some linguists derive the word from Proto-Nuclear Polynesian * kiwi, which refers to Numenius tahitiensis, the bristle-thighed curlew, a migratory bird that winters in the tropical Pacific islands. The Māori language word kiwi is generally accepted to be "of imitative origin" from the call. The kiwi is recognised as an icon of New Zealand, and the association is so strong that the term Kiwi is used internationally as the colloquial demonym for New Zealanders. Other unique adaptations of kiwi, such as their hairlike feathers, short and stout legs, and using their nostrils at the end of their long beak to detect prey before they ever see it, have helped the bird to become internationally well-known. The kiwi's egg is one of the largest in proportion to body size (up to 20% of the female's weight) of any species of bird in the world. At present, the greatest threat to their survival is predation by invasive mammalian predators.
All species have been negatively affected by historic deforestation, but their remaining habitat is well-protected in large forest reserves and national parks. There are five recognised species, four of which are currently listed as vulnerable, and one of which is near-threatened. Approximately the size of a domestic chicken, kiwi are by far the smallest living ratites (which also include ostriches, emus, rheas and cassowaries).ĭNA sequence comparisons have yielded the surprising conclusion that kiwi are much more closely related to the extinct Malagasy elephant birds than to the moa with which they shared New Zealand. Kiwi ( / ˈ k iː w iː/ KEE-wee) are flightless birds endemic to New Zealand of the genus Apteryx ( / ˈ æ p t ər ɪ k s/) and family Apterygidae ( / ˌ æ p t ə ˈ r ɪ dʒ ə d iː/).