How often have I sat on the veranda of an evening as the dusk deepens into darkness, waiting, listening for the cry of the Kiwi, only to be distracted by the hunting cry of Ruru, the owl. How long is it since I have heard the Kiwi, bird of the night, come out of the seclusion of its lair to wake the evening with its shrill reiteration of the call, “kiwi, kiwi”! stating his territorial challenge to anyone who wants to hear. To think they were once so numerous the early settlers complained that they could not sleep for their calls which may carry up to a kilometre in distance.
Kiwi calls are usually heard an hour before dawn and an hour after dusk, the calls being more frequent on dark moon less nights. Females give a lower hoarser cry compared with males but both birds, when alarmed or aggressive, growl, hiss and loudly snap their beaks together. As they wander through the forest at night, they are apt to make loud snuffling noises which is caused by the feeding kiwi forcing air out of its nostrils to clear the nasal passages of dirt as it probes the earth with its bill.
The Kiwi is the smallest member of that group of birds called the ratites, the group that contains the world’s largest birds, the emu, rhea, ostrich and cassowary, as well as the extinct elephant birds of Madagascar and the Moas of New Zealand. They are about the same size as domestic fowls, the females being about twenty per cent heavier than the males. The plumage is loose and hair like which gives them a shaggy appearance. They have long, slender, slightly downward curved bills with the nostrils near the tip and in this they differ from all other birds which have nostrils near the back of the upper bill. However, they are rarely seen and, until recently, little studied and so poorly understood.
The Kiwi is remarkably unbirdlike, so much so that the zoologist Stephen Jay Gould called them honorary mammals. They dig burrows like a badger and their faces bristle with catlike whiskers. Their shaggy plumage looks more like fur than feathers which gives them a rat like appearance. Indeed, they fill an ecological niche elsewhere occupied by anteaters, hedgehogs and echnidas.
Though Stewart Island brown kiwi emerge from their burrows to forage at dusk or on overcast days, the kiwi is a nocturnal bird. Kiwi, unlike other nocturnal birds, have poor vision — the eyes are small and the optic lobes of the brain very reduced. On the other hand the senses of touch, hearing and particularly smell, are very highly developed. Most birds have little or no sense of smell but Kiwi are an exception. The olfactory bulbs of the brain are very large and have a structure similar to that of mammals.
They are masters of camouflage and stealth which is a reason while they are more often heard than seen. Their plumage blends in perfectly with the bush and they often use different shelters each day. They dig their nesting burrows so long in advance that the moss and ferns re-establish themselves around the entrance. On leaving a burrow at night they often mask the opening with deftly placed twigs.
Territorial disputes are usually resolved by vocal duels but when driven their combat is a furious kick and tear kind of warfare with high jumps and slashing blows with their vicious claws. All Kiwi will put up a fight when cornered, the little spotted being the most vicious.
Given that Kiwi are nocturnal birds, they breed throughout the year, although more eggs are laid from July to February. The egg is a quarter of the female’s own weight. The male North Island brown Kiwi incubates the eggs, leaving only to go feeding a few hours each night. After 80 days incubation, the chicks are hatched and survives the first week of its life on its yolk sac. It is accompanied by the parent for a week or two and may even share a burrow with their father but after a fortnight the chicks are on their own and are very vulnerable, not only to predators but other adult Kiwi.
Little spotted Kiwi behave similarly to the North Island browns but the parents allow the young to remain in their territory for up to a year. Among the Okarito and great spotted Kiwi, the females play a much larger role in incubation, regularly taking turns incubating the egg.
On Stewart Island, Tokoeka live in large extended families with the juveniles staying with the parents and even helping in the incubating. This co-operative strategy is helping their survival and they have the strongest and most dynamic population of up to 20,000 birds, whereas the North Island brown is the species which is in trouble as the young chicks are not surviving in sufficient numbers to ensure their future.
In all species of Kiwi, brooding males develop a brood patch on their chests and bellies. Female Okarito Kiwi also develop this patch. When both parents incubate, the egg hatches faster. It is postulated that the reason why the North Island brown female plays no part in incubation is because she needs to conserve her resources to lay a second egg while the other species typically lay only one egg.
Maori call Kiwi te manu huna a Tane, the hidden bird of Tane. It was caught at night by imitating its cry, or in the daytime by the use of dogs which found its burrows. The Kiwi was used for food by Maori and its feathers were much valued for making cloaks. The cloak is known as a Kahu-Kiwi and is made by weaving the feathers into a base of flax fibre. Such feather cloaks were highly valued and often the feathers of white birds and the kiwi kura, the red kiwi, were used for borders and stripes.
In 1827, the North Island kiwi was met with at Tolaga Bay by d’Urville who, as commander of the French exploring expedition, was then visiting New Zealand in the Astrolabe. Shortly after this, in 1834, the Reverend W. Yate stated that this Kiwi was rare but found in the greatest numbers at Mount Hikurangi, which is inland from Tolaga Bay.
The naturalists of the French expedition that visited New Zealand in 1839 in the Astrolabe and Zelee, Hombron and Jacquinot, also obtained the North Island Kiwi and published a coloured plate of it in their report on the birds collected by the expedition.
Hitherto it had not been distinguished from the South Island Kiwi but in 1850 Mr Bartlett showed a series of specimens at a meeting of the Zoological Society of London and, comparing them with specimens taken from Dusky Sound, pointed out several differences. He accordingly named it Apteryx mantelli. A live specimen, presented to the Zoological Society by Lieutentant Governor Eyre in 1851, lived for some years and laid several eggs.
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»»» Song of Korimako
40 cm., male 2.2 kg., female 2.8 kg., Dark grey brown, streaked reddish brown, long ivory bill.
Where to find: —
North of Whangarei, Little Barrier, Kawau, Ponui Islands, Bay of Plenty, Gisborne to the northern Ruahine Range, Tongariro through to Whanganui, Mount Taranaki.
Illustration description: —
Rowley, G.D., Ornithological Miscellany, 1875-78.
Trevor Lloyd cartoon; this is claimed to be the first cartoon in which New Zealand was represented as a kiwi. More correctly, it is the first time it happened in New Zealand. The occasion was the victory of the New Zealand rugby team, the All Blacks, over England in December 1905.
Oliver, W.R.B., New Zealand Birds, 1955.
Page date & version: —
Tuesday, 9 August, 2011; ver2009v1