What is a kiwi?
Firstly, New Zealand’s national bird cannot fly! Endemic to New Zealand, the kiwi is unique among birds; no tail, the mere trace of wings and nostrils near the tip of it’s long flexible beak. Add nocturnal behaviour, whiskers, poor eyesight and hairlike feathers and it’s not surprising visitors to our south pacific islands are amused to find us New Zealanders calling ourselves “Kiwi” – especially many Americans who call our kiwifruit – “kiwi”.
Ratite’s, the family to which the kiwi belongs, evolved on Gondwana. This southern super-continent ( Jurassic period, 150 million years ago) split into what eventually became South America, Africa, Antarctica, Madagascar, India, Australia and New Zealand. New Zealand finally separated 85 million years and our flightless birds developed.
New Zealand has other flightless birds all of which are in danger of extinction. Apart from two bats, New Zealand had no terrestrial mammals until the Maori arrived some one-thousand years ago, bringing the kiore, (a Pacific rat) and the Pakeha (European) some eight hundred years later, who brought rabbits, possums, deer, stoat and many other animals. Before that, with no predators, it appears the birds had no need to fly and so lost the ability.
These introduced animals have been devastating these birds, and their habitat, since their introduction. Two of our flightless birds that you can see in Christchurch are the kiwi (Willowbank, Southern Encounter, Orana Park) and takahe. (Willowbank)
Despite being elevated to virtual icon status in it’s home country, the kiwi is a strange bird. Both male and female will fiercely defend their territory against other kiwi. They live in burrows and rotate the use of them to ensure a wide territorial presence. Kiwi feed mainly on earthworms and a variety of invertebrates such as slugs snails spiders and insects and occasionally have been seen wading in streams for larger prey such as frogs and freshwater crayfish. (koura)
Size varies according to the species, ranging from the little spotted kiwi weighing in at a mere 1150 grams to the great spotted kiwi which is twice that size. Females are usually the larger of the pair by as much as a kilo.
Mating for life the female lays a huge egg, approximately 20% of her body weight, then promptly leaves it for the male to incubate over the next eighty days. After three weeks this baby bird, a miniature of its parents, leaves the safety of the burrow to fend for itself. The small chick is extremely vulnerable to introduced animals and during its’ first year their mortality rate is high despite strong legs and razor sharp claws for defence.
Kiwi have shown considerable resilience in the face of habitat destruction by logging, pasture development and trees destroyed by possum as well as predation by stoats, dogs and other introduced animals. Human kiwi are hopeful that they can save the mainland populations of their namesake; that the bush will continue to hear the hedgehog-like snuffling as they search for food and the hoarse guttural sounds of the female as she calls to her mate.
TAKAHE – another of our flightless birds
Brilliant blue body, green wings and back combined with sturdy red legs, feet and beak make the takahe a bird not to be forgotten. Territorial, it lives in pairs and both parents incubate and raise the young. Unfortunately their fertility rate is very low with many of the eggs infertile.
Once found throughout NZ, it was thought to be extinct for over fifty years before being rediscovered by Dr. Geoffrey Orbel, in 1948, while he was bush walking. The population of only 200 continue to live mainly in the marginal environment of the South Islands Murchison Mountains, foraging for it’s favourite snow tussocks in competition with introduced herbivores.
Conservation measures include the eradication or reduction of the stoat which eat the eggs and the deer which feed on the same tussock. Management of their habitat is vital for their survival. Another measure to save these birds is to hatch eggs artificially. Removing one of the two eggs laid increases the number of chicks born as usually only one hatches in the wild. Young chicks are then reared; hand puppets for feeding, an artificial parent to shelter under and taped sounds of various feeding and alarm calls. This ensures they can be returned to the wild and are not dependent on humans. Chicks are later transferred to Kapati and Maud Islands in the Cook Strait or to a fenced area the Murchison Valley. One of my special memories is the time I spent as a Department of Conservation volunteer at the Te Anua Wildlife Centre with these beautiful birds and watched the young being fed with the puppets.