kiwi - Species, Discovery and documentation, Food

A flightless nocturnal bird, native to New Zealand; small eyes; acute sense of smell (rare in birds); long curved bill with nostrils at tip; strong legs; tail and wings not visible through thick, shaggy plumage; usually inhabits woodland; eats worms, other invertebrates, and berries; nests in burrow. Its egg is the largest, relative to body size, of any bird (25% of the female's weight). (Genus: Apteryx, 3 species. Family: Apterygidae.)

?Kiwi Conservation status: Vulnerable
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Struthioniformes Family: Apterygidae G.R. Gray, 1840 Genus: Apteryx Shaw, 1813
Species
See text.

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).

After an initial meeting during mating season (March to June), kiwi usually live as monogamous couples, unless a more suitable mate arises. (Source: KiwiRecovery.org) Kiwi eggs can weigh up to one quarter the size of the female. 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. (Source: Grzimek's Animal Life Encyclopedia)

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. With no constraints on weight from flight requirements, some Brown Kiwi females carry and lay a single 450 g egg.

It was long presumed that the kiwi's closest relatives were the other New Zealand ratites, the moa.

According to British scientists, the kiwi may be an ancient import from Australia. Upon examining DNA from New Zealand's native moa, they believe that the kiwi is more closely related to its Australian cousins. (Source: News In Science)

Species

Currently there are five accepted species (one of which has four sub-species), plus one to be formally described:

The largest species is the Great Spotted Kiwi, Apteryx haastii, which stands about 450 mm high and weighs about 3.3 kg. The North Island Brown Kiwi, Apteryx mantelli is widespread in the northern two-thirds of the North Island and with about 35,000 remaining is the most common kiwi. Distribution of these kiwi are 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.

Analysis of mitochondrial DNA, ecology, behaviour, morphology, geographic distribution and parasites of the North Island Brown Kiwi has led scientists to propose that the Brown Kiwi is three distinct species. The North Island Brown Kiwi; the Okarito Brown Kiwi (Rowi), whose distribution is restricted to a single site on the West Coast of the South Island of New Zealand; and a third distinct population of the North Island Brown Kiwi, the Southern Tokoeka, distributed in the in lowland forest to the north of Franz Josef glacier in the South Island and on Stewart Island, with a small population near Haast being another possibly distinct species, the Haast Tokoeka.

Discovery and documentation

The first kiwi specimen to be studied by Europeans was a kiwi skin brought to George Shaw by Captain Andrew Barclay aboard the ship Providence, who was reported to have been given it by a sealer in Sydney Harbour around 1811.

Food

Kiwi birds eat spiders, beetles, caterpillars, seeds, grubs, and many varieties of worms.