New Zealand is the natural home of the unique and fascinating New Zealand Kiwi bird. At Willowbank, protecting and educating the public about this very special, endangered species, is one of our most important roles as a wildlife reserve.
The Kiwi in New Zealand
The geographic isolation of the islands making up New Zealand means that 90% of our flora and fauna can be found nowhere else in the world (although some similarities are seen in South American forest life) and still flourish as they did 100 million years ago. Today New Zealand has only approximately 25% of its original (prior to human settlement) forest cover remaining.
The Kiwi Bird
Kiwi birds are one of the world's oddities. They have many mammalian features including two functioning ovaries, heavy bone marrow, cat like whiskers and hair like feathers, along with many unusual birdlike features. Kiwi lay the largest egg in proportion to their size of any species of bird at 20% of the female's body weight. Kiwis have very small wings, and almost one third of their total weight is made up from two heavily muscled legs. Their long bill allows deep probing into the ground for earthworms, and they have nostrils located on the tip of their bill, an adaptation that often requires a loud snort to clear.
Kiwi evolved for 70 million years before man introduced the many mammals that are found in this country now. Chick and eggs are very vulnerable to predators, which include possums, stoats, ferrets, feral cats, pigs and dogs. Also the removal of large areas of forest has reduced the habitat and left fragmented populations of kiwi across the country.
The male incubates the egg for 70 to 90 days. It can take four days for a kiwi chick to break out of its egg and by then it is exhausted. It is sustained with the yolk for a week and from then it must fend for itself. After hatching, it's a race against time to reach 1kg, when a chick is stronger and and more likely to hold its own. This can take up to a year. 95% of these chicks will be predated (killed) during the first few weeks of their lives so most populations probably consist of aging birds. We will therefore see a rapid decline in population as these birds begin to die of old age.
The Kiwi population of 80 years ago was around 5 million birds. Today they have plummeted to 50,000 - 60,000. This rapid decline in kiwi numbers is what has placed them on the endangered species list, and is the reason behind the kiwi breeding programme that takes place at Willowbank Wildlife Reserve through the New Zealand Conservation Trust.
North Island Brown Kiwi
North Island Brown kiwi are found in scattered populations throughout the North Island.
There is a small range of colour for these kiwi, from russet red to almost black and the occasional albino.
South Island Kiwi
South Island species and sub species are: Great Spotted, Okarito Brown (Rowi), Haast Tokoeka and Southern Tokoeka. Great Spotted Kiwi have dropped from 30,000 to approximately 10,000. Okarito Brown have dropped from 3000 to 350. Haast Tokoeka have dropped from 6000 to 350.
The little Spotted Kiwi was once found throughout both islands but is now only on predator free outlying islands.
Recovery Work on Kiwi
- The Kiwi Recovery Programme has been set up by the Department of Conservation to prevent the decline of kiwi numbers.
- 'Operation Nest Egg' The eggs are removed from the wild, hatched and reared in captivity then released back into the wild when big enough to defend themselves against predators.
- 'Communities for Kiwis' scheme manages patches of kiwi habitat on private and public land.
- Kiwi Sanctuaries - Five sanctuaries have been created covering 43,000 hectares protecting the critically endangered Okarito Rowi and Haast Tokoeka and some areas of North Island Brown kiwi. In these areas DOC has used intensive ground based predator control to knock the number of possums, stoats and ferrets to as low as possible. In some areas 1080 aerial baits are being trialed to assess the effects compared to trapping.
Kiwis at Willowbank - Kiwi Breeding
The kiwi breeding area covers an outdoor open area of bush land, approximately 2 hectares in size. This area has been extensively planted and is surrounded by a high predator-proof fence sunk deep into the ground. It is the home of several breeding pairs of kiwi. Rarely seen during the day, these birds are very active at night-time, and often viewed under the lights.
The juvenile kiwi can be viewed in a huge nocturnal house. At any one time there are up to 8 to 10 birds in this area. These are North Island Brown Kiwi that have been bred at Willowbank. Kiwi are naturally very shy and keep well hidden from humans but at Willowbank our kiwi are calm and relaxed. One of the best ways to see the kiwi at Willowbank is on one of our Night Tours or Kiwi Breeding Tours.
Willowbank has bred North Island Brown Kiwi for many viewing facilities and for advocacy in New Zealand.
Since 2005, the New Zealand Conservation Trust at Willowbank has been the only operation to take an active part in ‘Operation Nest Egg’ in the South Island, with both Okarito Brown Kiwi (Rowi), Haast Tokoeka and Great Spotted Kiwi eggs being hatched.
During last season alone, almost 71 Haast & Okarito eggs and chicks were hatched & reared on the premises. The eggs are driven or flown from a number of areas in the South Island, and on arrival are immediately put into incubators in the kiwi breeding centre.
Great Spotted Kiwi eggs are retrieved from Paparoa Park on the West Coast and Nelson Lakes.
As at the end of the 2009/10 season a total of 26 Haast, 45 Okarito, 1 North Island Brown, and 16 great Spotted Kiwi chicks were reared and released to creche sites.
The great Spotted Kiwi is the largest of all kiwi and is the only species found wild in Canterbury.
Kiwis bred at Willowbank Wildlife Reserve through the efforts of the New Zealand Conservation Trust and staff at the reserve, are part of New Zealand’s most successful captive breeding programme. Willowbank Wildlife Reserve is home to the largest open display of kiwi.
The rate of mortality is so high among chicks in the wild, that it is believed that adults are not managing to even raise two or three chicks in their lifetime. Both egg and chick are vulnerable to possums, stoats, ferrets, cats, dogs and pigs, but once they reach 1 kg in weight they are thought to have the ability to hold their own against predation.
As an endangered species, the Kiwi at Willowbank Wildlife Reserve come under the governance of the Department of Conservation, and the breeding programme is supported by funding sought by the New Zealand Conservation Trust. Willowbank Wildlife Reserve donates the time and expertise of its staff.