WHEN A nine-year-old parrot called Heather laid an egg in February, she became an international celebrity. Her story was broadcast on New Zealand’s morning news, and reached newspapers and magazines around the world. The reason for Heather’s overnight fame is that she is a kakapo, one of perhaps only 43 that survive. Her egg was a sign that her species may have won a reprieve at last.
The kakapo, the old night bird or owl parrot, is an extraordinary bird, however you look at it. An ancient species, Strigops habroptilus, and the only member of its genus, the kakapo is not closely related to other parrots and bears little resemblance to them. Larger than any other parrot, the kakapo weighs up to 3.5 kilograms. It is nocturnal, with many of the features of an owl – soft plumage and almost fur-like discs around its eyes. Stranger still, the kakapo cannot fly: it feeds, nests and rears its young on the ground. Unlike the gaudy parrots of Australia, the kakapo is beautifully camouflaged, with mottled mossy-green and yellow feathers. Camouflage is the bird’s main defence: when disturbed it freezes and hopes the intruder will go away.
For tens of thousands of years, the kakapo had little to fear, except perhaps from a giant eagle that is now extinct. In a land with no mammals except bats, the night parrot took the part of a monkey or a ground squirrel, eating all manner of vegetation – shoots, leaves and berries. Safe from predators, like many of New Zealand’s flightless birds, the kakapo had no need for ways to defend itself. Instead it developed the characteristics that now make it so vulnerable to predators that have been introduced into the country.
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The kakapo has a strong, sweet smell, like freesias; it is curious about strange things and very confiding. It never attacks, nor seems to make any real attempt to defend itself. Males make a lot of noise during courtship. They have a unique system of courtship for a parrot: the males gather – or they used to when there were enough of them – in arenas, or leks, where they display night after night in order to attract females. During their display, they make a resonant ‘booming’ sound, that travels like a foghorn over several kilometres, with the sole purpose of drawing attention to themselves.
After mating, the males have nothing further to do with the females. The female returns to her home range, which may be several kilometres away. There, she makes a nest on the ground and incubates her eggs alone. Without a partner, she has to leave the eggs, and later the chicks, untended for long periods at night while she feeds. Other species of ground-nesting birds have taken precautions to protect their young: usually they are hatched at an advanced stage of development and can walk (they are ‘precocial’). In any case, they instinctively stay still and quiet if danger approaches. The kakapo chick is ‘altricial’ – it is poorly developed and must stay in the nest for the first three months of its life. Worse, it makes a lot of noise both day and night.
Even more of a problem, as far as recovery from the edge of extinction goes, the kakapo breeds sporadically, only once in four or five years. It is probably the only flightless land bird that nests on the ground, has altricial young and a single guardian parent. ‘No other bird has the same features except perhaps the dodo,’ says Don Merton, of the Threatened Species Unit at New Zealand’s Department of Conservation in Wellington. The kakapo may soon exhibit the ultimate feature of the dodo and disappear altogether.
Kakapo once lived across most of the country. When the Maori arrived about a thousand years ago, they brought dogs and a rat called the kiore (Rattus exulans). Both killed kakapo. So did the Maori, who prized the kakapo for its meat and its warm feathers, which they made into cloaks. These first settlers also destroyed kakapo habitat by burning large areas of native vegetation.
Even so, when European settlers arrived in the 19th century, kakapo were still common in some parts of the country although people rarely saw them because they lived deep in the native bush. The Europeans ate kakapo occasionally but, more seriously, they cleared vast tracts of native vegetation and introduced browsing mammals such as deer, which also helped to destroy much kakapo habitat. Worst of all were the predators they brought with them: cats, dogs, ferrets and most particularly stoats and two more species of rat. Between them, they made short work of the kakapo.
The parrots retreated into inaccessible strongholds: by the 1950s, they survived only in some remote mountainous country in Fiordland in the southwest and on Stewart Island, New Zealand’s ‘third’ island to the South of the South Island. A first attempt at conservation began a century ago, when the government employed one Richard Henry to transfer as many flightless birds as he could to Resolution Island, a large island in Fiordland. Over several years, Henry transferred some 300 kakapo from the mainland – only to discover that stoats could swim to his safe haven. Kakapo have long since died out on Resolution Island.
The most recent attempt to save the birds began in 1974, when Merton and a team of wildlife officers flew into the remotest parts of Fiordland by helicopter to search the kakapo’s ancient stronghold. In the next three years, with the help of specially trained tracker dogs, they found 17 birds – all males. They took three to Maud Island, an island free from predators in the Marlborough Sounds, at the northern end of the South Island. In 1977, Merton and his team found a population of around 200 kakapo on Stewart Island – and discovered some all-important females. This population was still breeding and conservation suddenly became a real possibility.
But even these birds were not safe. Following the movements of the birds with radiotransmitters, the biologists found that feral cats were killing about half the population each year. A programme of cat control had some success, but it soon became obvious that it would never clear all the cats from the island. The alternative was to take the birds to a place where there were no cats. The kakapo, the Department of Conservation concedes, has no future on the mainland of New Zealand, nor on Stewart Island while the cats remain. In 1982, the team shipped 21 birds from Stewart Island to Little Barrier Island, off the east coast to the north of Auckland. Five years of intense trapping and poisoning had successfully rid this much smaller island of cats.
A single island refuge was not enough to guarantee the birds’ safety. So in 1987 the kakapo team began to move the last survivors from Stewart Island to nearby Codfish Island. Twenty males and 9 females are now on Codfish Island and the hunt is on for the last few birds that might remain on Stewart Island.
Today there are 43 known survivors. A census of Little Barrier Island last year turned up only 11 birds, although there may well be more; there are 29 on Codfish and 3 on Maud. Only 14 of the birds are females. Heather was the first known to have produced an egg since the birds were transferred to their new homes. She showed that removing the birds to a new island far from their original home could work. Despite the change, birds can breed.
If Heather and her fellows fail to make it, it won’t be for want of trying. Last year the Department of Conservation launched a five-year recovery plan for the species with a programme costing 2.5 million New Zealand dollars (around Pounds sterling 1 million). The plan is the first of its kind in New Zealand and gives the kakapo higher priority than any other species. A Kakapo Recovery Group of eight, led by Merton, has the job of managing the species back to safety. ‘Without intervention the kakapo is a doomed species. We can’t leave them to their own devices with all the problems we have given them,’ says Brian Lloyd, a kakapo biologist. Just how much the team intervenes is a delicate question. So much hangs on every move it makes. ‘We are constrained by risk,’ Lloyd admits. ‘We must minimise the risk of all our activities on the bird.’
Leaving the birds to fend for themselves in their new surroundings is not enough, however. Their island retreats might simply become ‘retirement homes’, where they live out the rest of their days until extinction. Fierce argument precedes every decision concerning the kakapo. In general, the Department of Conservation supports a ‘hands off’ approach to management, for fear that human interference might do more harm than good.
So far, intervention is limited to keeping down the numbers of kiore and supplying kakapo with extra food. Kiore are present on both Little Barrier Island and Codfish Island. No one knows if they will take kakapo eggs or nestlings, but they do take both eggs and chicks of other birds, such as bellbirds, tui and petrels. Female kakapo leave their eggs and nestlings at night while they search for food, staying away only an hour or so at first, but later leaving the nest untended except at feeding times, once or twice a night. The chicks hatch in the autumn, when the rats’ food supply is shrinking and hungry rats are more likely to attack chicks. Perhaps more of a problem, kiore compete for food with the kakapo: the rats reach their highest numbers when the female kakapo most needs a good supply of food close to the nest.
The recovery plan involves controlling rats, but there is no chance of eradicating them. Moreover, according to the ‘hands off’ guidelines, nesting birds are out of bounds, and must sit out their time on the nest without the benefit of rat controls.
The second form of help for the birds is provision of extra food. The idea is that better nourished birds might breed more often. In Fiordland and on Stewart Island, kakapo bred sporadically, in tune with the cyclical nature of their food supply. Although the birds eat many different plants – an analysis of faeces from Stewart Island revealed 57 species – every few years they receive a bonus when the native pines of the southern forests fruit. The birds seem to breed only during these heavy fruiting years. Codfish Island is very similar in most ways to Stewart Island, and shares this sporadic food supply. Little Barrier Island, 1100 kilometres to the north, provides a generally more varied diet but does not have these periodic bonuses.
The Department of Conservation has enlisted the help of Kerry James, a food biologist at the Department of Scientific and Industrial Research’s Biotechnology Division in Palmerston North. James’s task is to look at the kakapo’s diet and how to improve it. In general the bird’s diet is very poor; it provides little energy and contains very little protein or essential fatty acids. James suggested feeding the birds on a range of nuts, seeds and grains.
Following this advice, Ralph Powlesland, a kakapo scientist, began to feed the birds on Little Barrier Island last September. The first problem was to attract birds to feeding stations where the team could monitor what they ate. ‘Kakapo are fairly finicky,’ said Lloyd. But morsels of apple and kumara (New Zealand sweet potato) strategically placed on wires drew the birds in towards the stations. There, the team laid on a smorgasbord of grains, nuts, dried vegetables and commercial parrot foods. ‘They love brazil nuts and almonds, but they hate walnuts,’ said James. Individuals have particular favourites. ‘Some like sweetcorn, pears or kiwi fruit – but none likes the pelleted parrot mix.’ James is trying to formulate a special food for them, concentrating on the richer foods and leaving fruit and vegetables as lures.
It is too early to know if extra food will do any good. It could be years before the team discovers if the birds are breeding successfully let alone more often. The waiting will be hard. Some people have misgivings about such a cautious plan. They feel instinctively that bigger risks could bring bigger returns. In the case of the Chatham Island black robin, a species reduced at one stage to five individuals, only dramatic – and very risky – intervention saved it from certain extinction .
The recovery plan does make some provision for captive breeding in the future. With $1 million from Comalco NZ, the team is building enclosures on Maud Island. Members of the team feel it is important to take an egg from a nest, to see if the bird will lay another. Knowing that the kakapo does or does not ‘double clutch’ is fundamental to any plan for managing the species.
Before taking even one egg, it is essential to know how to look after it. No one has any experience of raising kakapo, but at Auckland Zoo, Mick Sibley, curator of animal operations, is trying the next best thing. As part of the kakapo programme, he is hand-rearing kaka chicks. The kaka is another of New Zealand’s large species of parrot, and it is endangered in some parts of its range. ‘If we have to rear kakapo, we must model our technique on kaka rather than any other parrot. This is the closest simulation we can get,’ says Sibley. To that end, he is looking at how best to incubate eggs and is monitoring the growth and development of chicks. He has had outstanding success. Ten kaka have hatched at the zoo this year, two of them incubated artificially, and eight raised by hand. Next year, Sibley will try to raise more kaka and kea, the third of New Zealand’s large parrots, feeding them different diets to see which they thrive best on. The ultimate test will be to breed from the hand-reared birds. Sibley is ‘quietly confident’ that his captive parrots will breed.
The information Sibley is accumulating will provide a firm base for raising kakapo. He has found, for example, that kaka chicks are covered with thick down – to keep them warm in the cool New Zealand climate. If they were kept at the usual temperature for parrot chicks, they would cook. ‘The kakapo recovery plan involves getting lots of people to hand-raise chicks – including aviculturalists, private people with experience of raising birds,’ said Sibley, who will coordinate such activities if and when they begin. No one will know exactly what to do until they try it, but Sibley’s findings will at least give them something to go on.
Another form of contingency involves setting up a facility for keeping birds in captivity, learning how to keep them before any attempt is made to breed from them. Three male kakapo have been taken to Maud Island, where they are ranging freely with radiotransmitters attached to their backs. First one, then all three birds, will be taken into captivity, where their diet will be manipulated in an attempt to bring them into breeding condition. Only when the team has found a diet that is acceptable and practical, and will reliably bring the male into breeding condition, can they begin to think about moving any females to Maud Island.
Even if captive breeding is some way off, captive birds will be an important source of information on the biology of the kakapo. Biologists know so little about the species, and it is extremely difficult to study such an elusive bird in the wild. Even on Little Barrier Island conditions are rough and remote, and birds are hard to find (even with trained tracker dogs). ‘We don’t understand what’s going on with the reproductive cycle,’ admits Lloyd. ‘Is it annual, but birds only breed when they have enough food – or is it more sophisticated? If we can find out about the cycle, it will help us to manage the wild population.’ James would also like a chance to study a captive bird, to analyse its diet more precisely.
Some of the biologists involved with the kakapo would like to see greater intervention on their charge’s behalf. The Department of Conservation’s general rule is that nests should be left alone. The fear is that intervention – by trapping rats around the nest for example, or even monitoring the progress of a clutch – might lower the bird’s chances of raising young. Some biologists argue that it is essential, at this stage, to know exactly what happens to the eggs and young.
This year two birds laid eggs on Little Barrier Island. Heather hatched a chick. It lived only a few days, and by the time the nest was checked, it was too late to say why the chick had died. Maggie, an older bird, also nested and laid an egg. She deserted the nest, probably because the egg was infertile. If the nests had been closely monitored, the biologists would know more about the kakapo and be better prepared next time Heather or one of her fellows starts to make a nest.
Time is running short. Although kakapo live for many years, perhaps 60 or so, the conservationists probably have only 10 years to reverse its precipitous decline. ‘We don’t know how long the birds live, but if, say, 10 per cent of the adults die each year, after 10 years we could be down to four or five females divided between two islands,’ says Merton. ‘More importantly, we don’t know to what age they can breed. Some females may be approaching the end of their productive life.’
Whatever the recovery team does, there are no guarantees. The softly-softly approach may achieve too little. Greater intervention could push the kakapo either way – back on the road to recovery, or beyond the point of no return.
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The robin’s return: a gamble that paid off
TEN years ago the future looked bleak for the black robin. The last five robins were hanging on in a patch of forest on a tiny island in the Chatham Island group, 850 kilometres east of the New Zealand mainland. Most people would have rated their chances of survival at zero. But Don Merton, then a conservation officer with the Wildlife Service, was not prepared to sit back and watch the robins slide into extinction.
Merton’s plans for the species involved drastic intervention in the robins’ efforts to breed. With extinction the only alternative, Merton and his team were given permission to interfere in ways no one had dared before. The risks paid off and the robins have made a spectacular recovery. A census after this year’s breeding season recorded 116 birds.
Although always restricted to the Chatham Islands, the black robin, Petroica traversi, was once common and widespread there. As for so many of New Zealand’s birds, human settlement, and especially European settlement, spelt disaster. The robins died out on the larger islands. Eventually the population retreated to a single rock stack and shrank to 20 or 30 birds. The population remained that size for almost a century, confined to 5 hectares of scrub forest on Little Mangere Island. In the 1970s, the vegetation deteriorated and the population plummeted. In 1976 all that was left were two pairs and three extra males. These birds were likely to die too, and so they were moved to neighbouring Mangere Island, after planting trees to provide more suitable habitat.
Like the kakapo, the black robin breeds slowly and so does not have the capacity to increase its numbers quickly. Females usually lay only 2 eggs, and the nesting cycle takes more than 3 months. However, in 1979, Merton found that if a pair loses a clutch, it will try again, so the birds have the potential to produce many more offspring than they actually do. Merton’s plan was to take the first-laid eggs and place them with foster parents of another species. The robins would then lay another clutch and raise the second brood themselves.
The risks involved in such a programme were huge. Merton and his team had to transfer the tiny eggs from a robin’s nest to that of the chosen foster parents, initially with no guarantee that the foster parents could raise their adoptive offspring. They had to find out how much manipulation the robins, and the foster species, would tolerate.
The first choice of foster parent was the Chatham Island warbler. The biologists found that the warbler would incubate the eggs, but could not raise the nestlings beyond 10 days old. Another species, the Chatham Island tomtit, was able to raise robin chicks to independence. But there were no tits on Mangere Island, so the team had to take eggs for fostering 15 kilometres by sea to another island, South East Island, adding yet more risk to the exercise. Things grew easier when Merton received permission to start a colony of robins on South East Island – a much better long-term home with more woodland than Mangere or Little Mangere. The main population of robins now lives there.
Merton’s management programme involved manipulation of the robin’s breeding cycles and those of the foster parents, to ensure that there were always enough foster nests throughout the robin breeding season. All the nests were protected from interference from other birds that might destroy them. Robins that did not nest in boxes provided for them were moved into nest boxes at the time of egg laying.
Merton could not afford to allow any robin chicks to die, not even allowing for natural mortality. Some chicks would normally die because an inexperienced male parent had not learnt how to feed them. Merton trained such birds by giving them older, less vulnerable, nestlings for a few days. Nestlings were also protected from parasites by providing them with clean, fumigated nests. Once fostered robin chicks reached 15 days old, they were returned to robins’ nests to avoid problems of imprinting on the foster parents.
The black robin programme is probably the first time cross-fostering has been used to manage an endangered passerine bird in the wild. The birds have recovered so well that they are now being left to build up their numbers unaided. The robins can never return to Chatham Island, where rats and cats would soon finish them off. But the Department of Conservation hopes to clear cats from Pitt Island, the second largest island in the group, to give the robin an even better chance of survival in the long term.
Not all the credit for saving the black robin belongs to Merton and his team. One particular bird, ‘Old Blue’ (named from the colour of her leg band), must share the honours. In 1976, Old Blue was one of two surviving females. She began to breed three years later, at the age of nine – by which time she was the only productive bird. Had Old Blue not lived to the extraordinary age (for a black robin) of about 13 years, breeding every year until her death, the species would certainly have become extinct despite all Merton’s efforts.
