Kiwi is a flightless bird that’s native to New Zealand. It is from the genus, Apteryx, and the Apterygidae family.
Subspecies of the Kiwi includes the Great spotted kiwi (Apteryx Haastii), Little Spotted Kiwi (Apteryx Owenii), Okarito Brown Kiwi (Apteryx Rowi), Apteryx Australis (Southern Brown Kiwi), and Apteryx Mantelli (North Island Brown Kiwi).
The kiwi is regarded as an icon of New Zealand, and the affiliation is so intimate that the term “Kiwi” is used globally as the colloquial demonym for New Zealanders.
It is assumed that the kiwi is a close relative to the other ratites in New Zealand for a long time.
Recent research on the extinction of genus, Proapteryx recognized that kiwi is lesser in size and could probably fly, leaning on the hypothesis that kiwi’s ancestor arrived in New Zealand independently from moas, which were already big and unable to fly by the time kiwi arrived.
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The kiwi has extensively adapted to terrestrial life, just like all the other ratites (ostrich, emu, rhea, and cassowary). These birds and kiwi lack one thing in common: the absence of a keel on the sternum to anchor wing muscles.
The vestigial wings are so miniature that they are unseen under the bristly, hair-like, two-branched feathers. While attaining maturity, most of these birds have hollow bones.
These kinds of bones lessen weight and make flight possible to practice, but the kiwi has marrows, similar to mammals and the offsprings of other birds.
With no restrictions on weight due to the criteria for flight, the brown kiwi females carry and lay a single egg that may weigh as much as 450 g (16 oz).
Like most other ratites, they have no gland for preening. They possess pliable, sensitive long bills, and the eyes have a smaller pecten.
The feathers of the kiwi do not have aftershafts and barbules. Nonetheless, they have large vibrissae around the gape. The kiwi possesses 13 feathers for flight, no tail, and a small pygostyle.
They have a weak gizzard, and their caecum is long and narrow. Compared to all other birds, the kiwi’s eye has the smallest eye to body mass relativity.
This results in them possessing the smallest visual field as well. The eye has small configurations for a night-time lifestyle, but kiwi leans more heavily on their other body senses which includes the auditory, olfactory, and somatosensory systems.
What kiwi doesn’t share with other palaeognaths, which are generally small-brained by bird standards, are that kiwi has comparatively large encephalization quotients.
Its hemisphere proportions are similar to those of songbirds and parrots, though there is no similarly complex behavior.
The habitat of a Kiwi could vary due to their high adaptability. It ranges from native forests, scrubs, rough farmlands, mangroves, dunes, tussocks, and plantation forests. They have a particular preference for wetland vegetations.
They are omnivorous creatures. The kiwi primarily feeds on miniature-sized invertebrates, fruit seeds, grubs, and various kinds of worms. They also feed on small crayfish, fruit, eels, and amphibians.
Because their nostrils are located at the end of their long beaks, kiwi can find insects and worms underground using their ultra-sharp sense of smell without actually seeing or feeling them.
The kiwi usually lays one egg per season. The kiwi’s egg is said to have one of the largest egg to body size proportions than every other bird in the world.
Even though the domestic chicken and the kiwi are roughly the same sizes, it has the ability to lay eggs that are approximately six times bigger than that of the chicken.
Their eggs possess a smooth texture and could either be ivory or greenish-white in hue. Incubation of the egg is the male kiwi’s responsibility except in the case of the Great Spotted Kiwi. For the Little Spotted Kiwi, both the male and the female are involved in the incubation task.
The period of incubation ranges between 63-92 days. Laying eggs of such sizes takes its toll on the female kiwi as it experiences considerable physiological stress.
During the thirty days it takes to grow and develop the egg fully, the female kiwi must eat up to her normal intake thrice.
Two or three days before the egg delivery or laying, it happens that there is barely any space in the stomach of the kiwi, and she resorts to fasting.
Kiwis are nocturnal creatures. They sleep during the day, and they feed or patrol during the night. All through the night, they spend their time foraging for food.
When it’s not foraging, it is going around its territory. It usually leaves behind very pungent droppings to mark its area as it walks.
Only its spouse, offspring, and mature children are not seen as hostiles on such territories. Any other Kiwi entering into this territory is seen as hostile and the kiwi will engage it in a fight.
Studies conducted nationwide reveals that only around 5–10% of kiwi chicks make it through to adulthood without pest management.
But in areas under active pest management, survival rates for North Island brown kiwi can be greatly increased.
Preservation measures taken towards the kiwi have been moderately successful, and in 2017, two species were downlisted from endangered to vulnerable by the IUCN.
In 2000, the Department of Conservation set up five kiwi sanctuaries centered on cultivating methods to preserve kiwi and to boost their numbers.
There are some Kiwi sanctuaries such as; Whangarei Kiwi Sanctuary (for Northland brown kiwi), Moehau Kiwi Sanctuary on the Coromandel Peninsula (Coromandel brown kiwi), Tongariro Kiwi Sanctuary near Taupo (western brown kiwi), Okarito Kiwi Sanctuary (Okarito kiwi), Haast Kiwi Sanctuary (Haast tokoeka).
Other conservation locations include Zealandia fenced sanctuary in Wellington (little spotted kiwi), Maungatautari Restoration Project in Waikato (brown kiwi), Bushy Park Forest Reserve near Kai Iwi, Whanganui (brown kiwi), Otanewainuku Forest in the Bay of Plenty (brown kiwi), Hurunui Mainland Island, south branch, Hurunui River, North Canterbury (great spotted kiwi).
North Island brown kiwi was brought in to the Cape Sanctuary in Hawke’s Bay within 2008 and 2011, which provided chicks raised in captivity that were released back into Maungataniwha Native Forest.