Apterygidae – Kiwis

Southern Brown Kiwi Apteryx australis ©Glen Fergus (Creative Commons) Website

Kiwis are flightless birds native to New Zealand, in the genus Apteryx and family Apterygidae. At around the size of a domestic chicken, kiwi are by far the smallest living ratites (which also consist of ostriches, emus, rheas, and cassowaries), and lay the largest egg in relation to their body size of any species of bird in the world.

DNA 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. There are five recognised species, two of which are currently vulnerable, one of which is endangered, and one of which is critically endangered. All species have been negatively affected by historic deforestation but currently the remaining large areas of their forest habitat are well protected in reserves and national parks. At present, the greatest threat to their survival is predation by invasive mammalian predators.

They prefer subtropical and temperate podocarp and beech forests, but they are being forced to adapt to different habitat, such as sub-alpine scrub, tussock grassland, and the mountains. Kiwi have a highly developed sense of smell, unusual in a bird, and are the only birds with nostrils at the end of their long beaks. Kiwi eat small invertebrates, seeds, grubs, and many varieties of worms. They also may eat fruit, small crayfish, eels and amphibians. Because their nostrils are located at the end of their long beaks, kiwi can locate insects and worms underground using their keen sense of smell, without actually seeing or feeling them

Their adaptation to a terrestrial life is extensive: like all the other ratites (ostrich, emu, rhea and cassowary) they have no keel on the sternum to anchor wing muscles. The vestigial wings are so small that they are invisible under the bristly, hair-like, two-branched feathers. While most adult birds have bones with hollow insides to minimise weight and make flight practicable, kiwi have marrow, like mammals and the young of other birds. With no constraints on weight due to flight requirements, brown kiwi females carry and lay a single egg which may weigh as much as 450g. Like most other ratites, they have no preen gland. Their bill is long, pliable and sensitive to touch. Their feathers lack barbules and aftershafts, and they have large vibrissae around the gape. They have 13 flight feathers, no tail and a small pygostyle. Their gizzard is weak and their caecum is long and narrow

Kiwi are shy and usually nocturnal. Their mostly nocturnal habits may be a result of habitat intrusion by predators, including humans. In areas of New Zealand where introduced predators have been removed, such as sanctuaries, kiwi are often seen in daylight.

Once bonded, a male and female kiwi tend to live their entire lives as a monogamous couple. During the mating season, June to March, the pair call to each other at night, and meet in the nesting burrow every three days. These relationships may last for up to 20 years.

There are just five species of kiwi in the family Apterygidae, all living exclusively in New Zealand; they are:

Southern Brown Kiwi Apteryx australis
North Island Brown Kiwi Apteryx mantelli
Okarito Kiwi Apteryx rowi
Little Spotted Kiwi Apteryx owenii
Great Spotted Kiwi Apteryx haastii

The kiwi is a national symbol of New Zealand, and the association is so strong that the term Kiwi is used internationally as the colloquial demonym for New Zealanders.

Number of Species
  • Number of bird species: 5

    All species are monotypic several having formerly been regarded as races of Southern Brown Kiwi.
Useful Reading
Organisations
  • Kiwi Conservation Club

    Website
    The Kiwi Conservation Club is a Forest and Bird project for children.
  • Kiwis for kiwi

    Website
    Kiwis for kiwi is carrying on the years of dedicated work by BNZ Save the Kiwi Trust, to help protect kiwi and the places they live. Because we can
  • NZ Kiwi Foundation

    Website
  • The Kiwi Trust

    Information
    The kiwi is New Zealand's national bird, and its future survival is of great concern not only to New Zealanders but internationally
Other Links
  • Incubation Temperatures of Great Spotted Kiwi Apteryx Haastii

    Article
    J.A. McLENNAN and A.J. McCANN - New Zealand Journal of Ecology, Vol. 15, No. 2 (1991), pp. 163-166
  • Metabolism and Temperature Regulation of Kiwis (Apterygidae)

    Article
    Brian K. McNab - The Auk, Vol. 113, No. 3 (Jul., 1996), pp. 687-692
  • Sexually dimorphic vocalisations of the great spotted kiwi

    Article
    Kiwi (Apteryx spp.) are the most vocal of the ratites. Of the 5 Apteryx species only 2 have previously been subject to detailed vocal analysis: the North Island brown kiwi (A. mantelli) and the little spotted kiwi (A. owenii). This paper describes the vocalisations of the great spotted kiwi (A. haastii), the largest of the Apteryx species....
Photographers & Artists
  • Brown Kiwi Apteryx australis

    Gallery
    Excellent image
  • Great Spotted Kiwi Apteryx haastii

    Video
  • Little Spotted Kiwi Apteryx owenii

    Video
    Taken on a night tour at Zealandia wildlife sanctuary in Wellington, New Zealand on January 13, 2014.
  • Northern Brown Kiwi Apteryx mantelli

    Video
    This video is from the Otorohanga Kiwi House & Native Bird Park and shows a Kiwi chick hatched 11 October 2009 being removed from its underground burrow to ensure its survival as this species of native New Zealand bird is a threatened species.

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