Kiwis are flightless birds native to New Zealand, in the genus Apteryx and family Apterygidae.
Kiwi don’t need pristine native forest, and are found in scrub and rough farmland, exotic plantation forests, sand dunes and snowy tussocks, even mangroves.
The lifespan of kiwi is about 20 to 30 years in the wild and up to 40 years in captivity.
There are five known species of kiwi, as well as a number of subspecies.
• Little spotted kiwi (Apteryx owenii) on several offshore islands and two mainland sanctuaries
• Great spotted kiwi (A. haastii) in the northwestern South Island and around Arthur’s Pass
• Brown kiwi (A. mantelli) in the North Island
• Rowi (A. rowi) at Okarito, on the West Coast of the South Island
• Tokoeka (A. australis) in the South Island (Fiordland, the Haast Range and Rakiura (Stewart Island)).
The largest species is the great spotted kiwi or Roroa, Apteryx haastii, which stands about 45 cm (18 in) high and weighs about 3.3 kg (7.3 lb).
The smallest species is the little spotted kiwi, Apteryx owenii, which stands about 25 cm (9.8 in) high and weighs about 1.3 kg (2.9 lb).
The unique adaptations of kiwi, such as their large eggs, short and stout legs, or 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 eye of the kiwi is the smallest relative to body mass in all avian species resulting in the smallest visual field as well. The eye has small specialisations for a nocturnal lifestyle, but kiwi rely more heavily on their other senses (auditory, olfactory, and somatosensory system).
Its wings are only about 3 cm (1 in) long and are useless, completely hidden under the feathers.
The kiwi has no tail but does have very strong, muscular legs, which make up about a third of the bird’s total body weight, that are used for running and fighting.
Four toes (other ratites have only two or three) on each thick foot allow the flightless bird to pad silently through the forest in search of food. Despite its small size and awkward appearance, the kiwi can outrun a human and is quite wary.
While most birds have thin skin and hollow bones to make them lighter for flying, the kiwi’s skin is a bit thicker and tough, and its bones are heavy and filled with marrow.
Kiwi are nocturnal. Like many other New Zealand native animals, they are most active at night. Throughout the night, they spend their time foraging for food.
To keep track of each other in the dark, kiwis can shriek loudly, a half scream, half whistle that also serves to scare others away. This cry sounds like “kee-wee, kee-wee,” which is how the bird got its name.
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.
Kiwi eggs can weigh up to one-quarter the weight of the female. Usually, only one egg is laid per season. The male incubates the egg, except for the great spotted kiwi, A. haastii, in which both parents are involved. The incubation period is 63–92 days.
Unlike other birds, chicks kick their eggs open and are covered in feathers as soon as they hatch. They look like tiny versions of their parents.
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.
Four out five species are currently listed as vulnerable, and one of which is near-threatened.
The kiwi is thought to be the world’s most ancient bird, evolving over 30 million years ago.
The Māori language word kiwi is generally accepted to be “of imitative origin” from the call.”
The Māori traditionally believed that kiwi were under the protection of Tane Mahuta, god of the forest.
The kiwi is 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.
The kiwi as a symbol first appeared in the late 19th century in New Zealand regimental badges. It was later featured in the badges of the South Canterbury Battalion in 1886 and the Hastings Rifle Volunteers in 1887. Soon after, the kiwi appeared in many military badges; and in 1906, when Kiwi Shoe Polish was widely sold in the UK and the US, the symbol became more widely known.