to save the kiwi

Forest and Bird, Issue 292, 1 May 1999, Page 14

to save

the kiwi

is a scientist with

the Department of Conservation where he is head of the Kiwi Recovery Programme.

HUGH ROBERTSON.

—HUGH ROBERTSON

Southern tokoele Stewart Island The Kiwi Rerovery Programme 1 sponsored by the Bank @f New Zealand: For further information Iook on the Internet for the Kiwvi Recovery web-site; WWW kiwirecavery org-nz

kiwi recovery discoveries The Kiwi Recovery Programme provides both science and know-how which could help Save the kiwi from

extinction; says

iwi are in serious trouble. During milof years of isolation, kiwi evolved nocturnal flightless lifestyle and characteristics that equipped them well to escape from avian predators. But, like many other native birds, they are unable to cope with the motley collection of predatory mammals brought here by people. Loss of forest habitat, combined with carnage by introduced mammals, has seen kiwi populations collapse from tens of millions a thousand years ago to about 70,000 today. The Kiwi Recovery Programme was_ launched eight years ago to try to save our national bird from extinction. The aims ' were three-fold: | @ to find out about the numbers, distribution and genetic variation of kiwi; @ to find out what was threatening kiwi populations; @ and to start to manage the recovery of the most endangered populations of kiwi. Forest and Bird is an active partner in this ° programme alongside the Bank of New Zealand which funds much of the research, the Department of Conservation, and the many Kiwis who help with management or who make donations to the programme. The results are considerable progress in understanding the . ecology of the various species of kiwi, the threats they face, and the development of heartening management techniques which could arrest the birds’ free fall to extinction. In the early 1990s, we established where kiwi still survive. The news was worse than expected — some important populations had recently collapsed. Pat Miller and Ray Pierce documented the almost complete disappearance of brown kiwi in southern Northland since the 1970s, even though abundant habitat remains. Major declines were also apparent in the Waikato, King Country, Bay of Plenty, East Coast, Ruahine Ranges, West Coast and eastern Fiordland. _ Kiwi scientists pooled data from their mainland studies and found that adult mor- | tality averaged seven to eight percent per year, while ‘recruitment’ (new birds) was only one to two percent each year. The sum of these figures meant that mainland populations _were declining at an alarming six percent per year, which equates to a halving in numbers every decade. At this rate of decline, the kiwi population on the mainland would have been close to five million birds when Forest and Bird was established in 1923, but another 75 years hence, there will be a paltry 600 birds left, probably living as widely separated and lonely individuals. | When the programme started, the main | threats to kiwi were not well known, apart from the obvious dangers of habitat loss, possum traps and dogs attacks.

iwi were hunted by Maori and their and fires swept through large parts of the drier eastern side of both main islands in pre-European times. Habitat loss accelerated rapidly with settlement by Europeans as they carved farmland out of prime kiwi habitat. Over 80 percent of the lowland forest standing in 1840 has been lost, and much upland forest has also gone. Potential and existing kiwi habitat across the country is still being cleared for farming and forestry. Breaking in a farm represents a permanent loss of habitat for kiwi, but plantation forestry may provide replacement habitat. The main effects of forest or scrub clearance is to destroy nests. Adults may also be killed under roller-crushers or bulldozers, and the social structure of the local kiwi population is disrupted as refugees move into the territories of neighbouring birds Kiwi eggs take a long time to hatch, and some kiwi varieties leave them unattended for long periods of the night while the male is out feeding. About 50 percent of eggs fail to hatch. This may be because of accidental breakage (perhaps caused during disputes over burrow ownership with possums or other kiwi), microbe attacks, predation, abandonment or infertility. On the mainland, the worst predators are possums, mustelids and kea. Weka take many little spotted kiwi eggs on Kapiti Island, but numbers of both species have increased on the island during the 20th century, and our work shows that little spotted kiwi are thriving, and are close to the carrying capacity of the island. Once the egg stage has been successfully traversed, the kiwi enters the most dangerous part of its journey to adulthood. Kiwi chicks hatch as miniature adults, fully feathered and able to feed themselves. In some varieties they become completely independent at two to five weeks old. In the case of the southern tokoeka on Stewart Island, however, the first chick hatched continues to return to the nest while the next egg is incubated, and the chicks remain in the family group for up to seven years. On the mainland, an appalling 95 percent of young kiwi die before they reach six

months old. Most fall prey to stoats or cats. Once juveniles reach a weight of about one kilogram at about six months old, however, they become safe from these voracious predators. This discovery is behind the techniques adopted by Operation Nest Egg which takes eggs from the wild and raises chicks in captivity until they are big enough to defend themselves. (See box, page 18.) Kiwi have the potential to live to 30-40 years of age, but mainland birds face many threats. The kiwi’s chest is fragile as it lacks a sternum and wing muscles to protect the lungs and so a dog can kill a kiwi just by picking it up. The kiwi has a very strong scent and dogs can quickly learn to find birds. In one tragic incident at Waitangi State Forest in 1987, a German Shepherd may have killed up to 500 kiwi — or 50 percent or the resident birds — during a six-week rampage. Unfortunately this was not an isolated incident; between 1990 and 1995, there were 135 reports of kiwi being killed by dogs in Northland, including several other ‘massacres. Although dogs are an obvious problem, ferrets probably pose a greater threat to adult kiwi in most parts of the country. These large mustelids were introduced to New Zealand in the 1880s in an unsuccessful bid to control rabbits. Despite being a voracious killer of native animals, they may legally be kept as pets, and are farmed for their fur. Fitch-farming was popular in the 1980s, but when the fur market collapsed many unwanted animals were released to the wild. These ferrets probably went on a killing spree and to compound matters, they were released into parts of the country where ferrets were rare or absent. For example, in the mid-1980s, about 200 kiwi lived in a reserve near Tangiteroria in Northland, but ferrets appeared in the area in 1987 and by 1994 the kiwi population had crashed to about 30 birds. In central Northland, a male ferret killed three of 10 radio-tagged male kiwi in a 35-hectare bush

patch of over a by two-month period and two other nearby birds were killed about the same time — this ferret was trapped and the mayhem ceased. Serial killing has also been recorded at Te Urewera National Park. Although the odd kiwi is killed by possum, their main impact is indirect, when kiwi are accidentally killed by possum traps or poison. Many injured kiwi have been handed to veterinarians or bird rescue centres with damaged legs or bill as a result of an accidental encounter with a trap, and many others are killed outright or escape minus toes or a foot. During the peak of possum-trapping in the late 1970s and early 1980s, 35 percent of kiwi in some sites had signs of gin-trap injuries, and undoubtedly many others died from their injuries. Possum-trapping has lessened as fur prices have dropped yet a steady flow of injured kiwi are still handed in. The Department of Conservation has taken the lead by using only soft-jaw traps, and by raising them over 70 centimetres off the ground in parts of the country where there are ground-dwelling birds. The traps are set on branches or treeforks, on sloping boards, or on small platforms attached to the tree trunk. Kiwi sometimes eat cyanide baits on the ground and so bait stations should be raised well off the ground. Less than five percent of little spotted kiwi on Kapiti Island were accidentally poisoned during the aerial application of brodifacoum to eradicate rats. (The surviving birds bred well and quickly made up their losses as most of the competing weka were temporarily removed from the island). Other recent research has shown that adult kiwi have not been affected by similar aerial operations using 1080 poison, or when brodifacoum baits are repeatedly placed in bait stations for several years. In these studies, chick survival in the poisoned areas was far better than in untreated blocks nearby, because predator numbers were reduced, allowing the kiwi populations to start to recover. All kiwi face natural hazards such as disease, getting tangled in tree roots, being hit by falling branches, drowning, falling into holes, or being "beaten-up’ by another kiwi. They also face a number of manmade hazards such as falling into cattle stops, swimming pools or cowshed effluent ponds. Others are hit by cars, shot in mistake for possum, or killed by bulldozers or roller-crushers. Now that the various threats are better understood, the recovery programme has moved towards experimental management to recover the most endangered populations, and to restore depleted kiwi populations. One experimental technique used to overcome the vulnerability of eggs and young chicks is the programme called Operation Nest Egg. Eggs

and/or young chicks are removed from the wild to the safety of captivity, or a predator-free island, until they are able to cope with stoats and cats. (See box opposite.) Successful management of predators, through intensive trapping or poisoning, has greatly increased chick survival, and allowed selected populations to start to recover in Northland and at Lake Waikare-moanaa. This work has been on a small scale, protecting birds in areas ranging from 40 hectares to 700 hectares, but the next step is to try to improve the cost-effectiveness of management, to develop better pest control techniques, and to increase the scale of operations. iwi are good indicators of environKe se health, and management to benefit kiwi also helps many less charismatic species of native wildlife. Forest and Bird’s Kiwis for Kiwis campaign, based on developing eleven management sites of 10-20,000 hectares for kiwi throughout New Zealand, is ambitious with current technolo-

gy but would certainly go a long way towards ensuring that the birds were prospering in the natural ecosytems on the mainland where they have been for tens of millions of years. Many kiwi still survive on private land or close to people; so changing the attitudes and behaviour of people is important for the survival of these birds. The recovery programme has targeted such areas to raise awareness about the threats kiwi face and the actions people can take to maintain kiwi populations. Some communities, such as in the Bay of Islands and Coromandel, have ‘adopted’ their local kiwi populations and are dealing with many of their threats. Changes in legislation and public attitudes which could better protect kiwi and their habitats will underpin a sustainable recovery. If kiwis continue to get behind the recovery programme, the battle to save kiwi can be won!