The following information was extracted from the publication "Threatened"
produced by BNZ in cooperation with the Department of Conservation
and Royal Forest and Bird Protection Society.
The Predation Threat
In 1987, a dog was on the loose in Waitangi State forest in the Bay of Islands. For six weeks it rampaged through the forest killing every kiwi it encountered. By the time the dog was found, perhaps as many as 500 of the 1000 kiwi living there had been slaughtered. This carnage at Waitangi illustrates just how vulnerable the kiwi is to predators and the speed at which seemingly healthy populations can fail.
Other predators introduced to New Zealand by humans may cause similar havoc. The main threat to the kiwi is posed by: Possums, stoats, ferrets, and feral (wild) cats who steal eggs and kill young. Larger predators include pigs and dogs.
Young kiwi leave the nest at just three weeks of age, weighing only 200g. Small and slow, they are easy prey. Very few survive this precarious journey from birth to 12 months, when they reach the critical size that enables them to stand up to most predators.
Humans, primarily through destroying forests and introducing predators in the first place, pose the single greatest threat to the kiwi. Ironically, we are also their greatest hope.
The kiwi is a one-off evolutionary design, holding all sorts of biological records. New Zealand's ancient isolation and lack of mammals allowed it to occupy a habitat and lifestyle that everywhere else in the world would be occupied by a mammal.
Whereas birds traditionally depend on sight, the kiwi is one of the few birds with a highly developed sense of smell. You can sometimes hear them sniffing around in the dark. Alarm them during the day and they will run off. Then, at a distance, just like a wolf or other mammal, they'll stick their bill (nose) in the air, sniffing to see if they are safe from pursuit.
Other reasons the kiwi could pass for a mammal is its loose, hair-like feathers, its long whiskers, the fact it can't fly and that it burrows in the ground.
Other kiwi curiosities include:
Being the only known bird to have external nostrils at the end of its bill. It literally sniffs out its food a bill-length below the surface.
It's huge eggs. The kiwi has one of the largest egg-to-body weight ratio of any bird. The mature egg averages 20% of the female's body weight. Compare that to 2% for an ostrich!
Being the smallest living member of the ratite family (which includes ostriches and emus).
They live in pairs — as monogamous couples — for most, if not all of their lives.
Sex role reversal: The female is bigger and dominates the male.
In some varieties, the male does most of the incubating of the eggs.
The eggs take an exceedingly long time to hatch — up to 80 days.
Kiwi tend to live in pairs, forming monogamous couples. These bonds are generally till death and have been known to last over 30 years. About every third day, the pair will shelter in the same burrow together. The relationship tends to be quite volatile and physical, the female generally calling the shots over her smaller partner.
During the night, as they are out foraging for food or patrolling their territory, they will perform duets, calling to each other. The female has a lower hoarser call than the male.
From the outside, it doesn't appear that kiwi domestic life is bliss. But the bond is long-lasting.
There are few surprises in the kiwi diet. It's mostly earthworms, spiders, fallen fruits and seeds, larvae of beetles and cicada and a mixture of forest invertebrates. But they will also take large food items like freshwater crays and even frogs. In captivity, kiwi have fished eels out of a pond, subdued them with a few thuds and eaten them.
Kiwi are extremely territorial birds, They protect their patch — which can be as much as 40 hectares — by calling or, if that fails, by chasing the intruder kiwi and giving it a good booting over. Very occasionally, kiwi kill each other fighting for territory.
Acutely aware of neighbours, they will often engage in calling duels. If a bird is intruding into another's space, it will rush back at full speed into its own space before returning a neighbour's call.
A gathering of kiwi is a rarity. However, on Stewart Island, they do live in small, mixed aged family groupings.
Kiwi Nests, er, Burrows!
Kiwi are burrowers. They may quickly clear a burrow at the end of a night's work, crash there during the day and then move on to a new burrow the next day.
Great Spotted Kiwi prefer dens. Unlike the Little Spotted Kiwi and the Brown Kiwi, who tends towards simple one-entrance burrows, the Great Spotted will put the time and effort into constructing a labyrinth of tunnels several metres long with more than one exit.
Common Kiwi Myths
Kiwi experts are keen to dispel myths surrounding the kiwi — particularly that they are half-blind and bumbling.
Here are a few common ones:
Myth: "Kiwi fight with their beaks."
To use their beaks to fight would be like head-butting someone with your nose.
At the end of the beak are the kiwi's external nostrils. Finely tuned and capable of detecting a few parts per million of scent, the beak, when probing the ground, can detect worms and other food.
Myth: "Kiwi are cute, gentle little creatures."
They are actually super-strong and often extremely bad tempered. The adults can look after themselves using their razor sharp claws as weapons. A couple of slashes can quickly draw blood — as conservationists have often found when putting their hands down kiwi burrows.
Because they are so aggressive, DOC staff can attract them simply by imitating their call. Incensed that another kiwi is on their turf, the response is instant and dramatic:
"It's amazing to hear them coming to kick the intruder out. They sound like a deer charging, almost exploding, through the dark. Standing there, it's quite intimidating. I guess it's part of the threat display."
"Pete" is a Great Spotted Kiwi in West Northland. "We've just got to walk into his territory and he comes catapulting in for a hit-and-run. He belts you in the leg and then runs off into the undergrowth. I think he views us as super-big kiwi. He's probably given some trampers a helluva scare."
Myth: "Kiwi are a bit thick."
According to Conservation Officers who know them best, they are capable of learning quickly and altering behaviour in the light of experience.
Myth: "Kiwi move slowly."
Superbly adapted to their natural habitat, the kiwi is extremely agile and quick moving. A kiwi can cover his territory — possibly the size of 60 football fields — in a night. This might take in three valley streams and all sorts of obstacles.
Myth: "Kiwi and half-blind."
The notion of their being half-blind probably stems from their being nocturnal and having small eyes. In fact, as Conservation Officers can testify, if you chase them at night, they can run very fast, swerving around trees and expertly navigating the undergrowth. Similarly, they are unfazed by daylight.
Kiwi Culture -- From a Maori Perspective
The Maori people have a very personal interest in seeing the kiwi survive and flourish.
According to many Maori traditions, the kiwi is the oldest of all Tanemahuta's bird family. It was Tane, the god of the forest who, with different wives, created much of the natural world, including birds, trees, stones and humans.
For Maori, kiwi are, in effect, our elder siblings. And, like a good older brother or sister, they are very protective of us. That's partly why they patrol the forests nightly.
Kiwi -- Six Unique Varieties
There are six identified varieties of kiwi.
The Little Spotted Kiwi
The smallest (about the size of a bantam) and most endangered species, the "Little Spots" have a very mellow, often docile nature. They have suffered terrible that the hands of possums, stoats, cats and larger predators.
Now extinct on mainland New Zealand, the largest remaining population is on Kapiti Island where 1000 birds occupy some 1900 ha of mixed forest, scrub and grassland. Sensitive management by DoC and the Maori Trustees of private land on Kapiti are ensuring that cats, dogs and other kiwi predators don't reach the island.
The Great Spotted Kiwi
The rugged mountaineer of the kiwi — found primarily in the high, often harsh hill country — the Great Spotted has forged a strange deal with evolution. The same harsh environment that makes it struggle from one day to the next also makes it tough going for the pigs, dogs and stoats that would otherwise be keen to pursue it.
Big bold and handsome, it is found only in the South Island, mainly in North West Nelson, Central Westland and Eastern Canterbury.
The North Island Brown Kiwi
Bug noses and short tempers is one way to sum up the Brown Kiwi. They are little toughies ... and have to be to survive against humans, introduced predators and the natural challenges of their often harsh bush existence.
The North Island Brown Kiwi is found only in the upper two-thirds of the North Island. They are widespread in Northland in a diverse range of vegetation types including exotic forests and rough farm land.
Okarito Brown Kiwi
In one sense, the new kid on the block. It was only in 1993 that the Okarito Brown, living in lowland forest just north of Franz Josef was identified as a distinct variety of kiwi. Tell-tale signs are its slightly greyish plumage sometimes accompanied by white facial feathers.
Squat and round and bigger than their northern Brown Kiwi cousins, they can grow to almost the same size as Great Spotted Kiwi. The Southern Tokoeka are found in Fiordland and on Stewart Island. They are the most communal of the somewhat reclusive kiwi.
The Haast Tokoeka, found in the rugged mountains behind Haast, was also identified as a distant variety of Kiwi in 1993. They spend their summers in the high sub alpine tussock grasslands but probably retreat to the lowland forests in winter.
Kiwi Sightings -- Where You Can See Kiwi
Few of us get the chance to see a kiwi in the wild but Brown Kiwi can be seen at the following places: