The kiwi's name is not derived from its call, as is often believed, but rather from the Polynesian name for the bristle-thighed curlew, the kivi. This tropical seabird has a similar habit of poking for food with its long beak, albeit along the coast.
An honorary mammal
A ratite, and therefore related to the moa, emu, ostrich, cassowary and rhea, the kiwi is 'an honorary mammal' in that
it occupies niches that elsewhere are the domains of moles or badgers
it maintains an average body temperature of 38oC, two degrees below that of most birds and closer to the mammal range
instead of having hollow bones, as most birds do, kiwi bones are filled with marrow
the female has a pair of functional ovaries instead of the one that most birds have - again a feature typical of mammals.
The kiwi also stands apart from other birds because of its superior sense of smell. The kiwi snuffles like a hedgehog as it shuffles through the bush, continuously probing the soil for worms.
There are two species:
the great spotted and little spotted kiwi are holding their own better than the brown, even though there are more individual brown kiwi. The little spotted kiwi occurs only on islands, while a portion of the great spotted kiwi population lives in alpine areas less hospitable to predators.
the brown lives at low altitude, often close to human settlement where it has to cope with a variety of enemies.
Prior to human arrival in New Zealand about 1000 years ago, there may have been up to 12 million kiwis rustling about in the rainforests at any one time. For the moment the brown and the great spotted kiwi survive on the North, South and Stewart islands, but dogs, pigs, cats, stoats, ferrets, possums and humans threaten them - a formidable list of enemies.
There are two species: