by Scott Leslie
By the early 1970s, many thought that the bird was extinct. In fact, it was extinct on the more highly populated North Island. But in 1977, a population of 100 to 200 birds was found by an expedition to remote Stewart Island, which lies off the southern tip of South Island. This last population survived only because of the inaccessibility of its habitat. But even on this lonely outpost, the long reach of humans was having an effect. Feral house cats, introduced earlier (deliberately or accidentally) by humans, were killing almost 60 percent of the birds every year. The population wouldn’t last long at that rate, so a cull of Stewart Island’s marauding cats was carried out. Although the cats were successfully eradicated from the island, in the 1980s conservationists decided to begin moving the remaining birds to predator-free islands where they would be safe. By 1992, 65 kakapos had been successfully relocated to their new island homes. Today, they live on two predator-free islands: Codfish Island and Anchor Island. Here they are carefully monitored by biologists to ensure breeding success.
Even if they’re safe, building the population back to self-sustaining levels has not proven to be easy. Since females normally don’t breed until they are about nine years old and generally do so only every second year, the road back to full, independent specieshood is going to be a long one. In early 2011, there were a total of 120 kakapos. That is almost twice the number of two decades ago, but there is still a long way to go before they’re able to survive on their own. No doubt it will be difficult road to recovery for the kakapo, but the success of the crested ibis shows us how much can be accomplished when rescuing an endangered species.
CRESTED IBIS
From the 17th to the 19th century, the crested ibis was officially protected in Japan. The Tokugawa shogunate (the samurai rulers of the time) revered the species and forbade any hunting or capture of these large wading birds.
Their abundance under shogun protection would quickly cease after the Meiji Renewal in 1868. This ended military control and restored imperial rule to Japan. The shoguns lost power, and many of their edicts were repealed, effectively ending protection for the ibis. From then on, the species went into serious decline. A combination of widespread poaching to collect its long crest plumes for the millinery trade, destruction of its forest and wetland habitats, and the heavy use of pesticides had reduced the crested ibis to just a handful of birds by the 1960s. Only five individuals remained in all of Japan in 1981. Something had to be done, for at the time, these were the only known crested ibis left anywhere, and the fate of the species was thought to be at hand. In January of that year, the five were captured and kept in the Sado Japanese Crested Ibis Conservation Center on Sado Island, on the west coast of Japan. The intent was to breed them in captivity to bring the species back from the edge. It was not only Japan that lamented the decline of the crested ibis. Once ranging across much of eastern Asia, by this time the species had already become extinct in Taiwan, South Korea, North Korea, and apparently China.
But later in 1981, to everybody’s surprise and delight, the crested ibis was found surviving in a remote, mountainous area of Yangxian County, Shaanxi Province, China. The tiny population of four adults and three chicks was the first of the species to be seen in that country in a half century.
With a wingspan of 140 centimetres, the crested ibis is a spectacular, large wading bird. Snow-white plumage in the non-breeding season (its head, neck, and back turn dark grey in the breeding season) and a large shaggy crest of long plumes contrast with its brilliant red patch of facial skin, red legs, and long down-curving black bill tipped in red. Like many freshwater wading birds, the species has a varied diet that includes small fish, frogs, crabs, snails, molluscs, and insects. It gathers these by probing its bill into the water, mud, or long grasses along riverbanks, ponds, and rice paddies. Tall trees are a key part of its breeding habitat. Mated pairs build a flimsy nest, high up in the crotch of a large tree. Both sexes incubate up to five eggs and both feed the newly hatched young.
By 1990, less than a decade after the seven Chinese birds and their habitat were stringently protected, the population had grown enough that 25 ibis chicks were captured for a captive breeding program, a cooperative effort of both Chinese and Japanese conservationists. Within a decade, that number had increased to 130 birds. The species was well on its way to a comeback in China. By 2002, there were 140 birds in the wild and 130 in captivity. The story was not so rosy at the Sado Island conservation centre in Japan. Those five ibises captured in 1981 failed to produce any young, and the last survivor of the group, a female named Kin, died in 2003 at the ripe old age of 36 years.
Chinese birds were sent to Japan in an attempt to repatriate the species to a land where they were now absent. Fortunately, years of experience had taught scientists a thing or two about how to successfully breed captive crested ibis. Armed with this knowledge, the Sado Island facility would once again host the magnificent birds. Today, there are over 100 crested ibis in captivity at the conservation centre, all awaiting eventual reintroduction into the wild. In 2008, a dozen or so ibises, gifts from China, were released into the Japanese wilds. For the first time in decades, a wild-living crested ibis laid eggs in Japan in 2010. Although they didn’t hatch, it marked a watershed for the species there.
According to the Chinese government, the official number of crested ibis living in that country in 2010 stood at 1,617—997 of which lived in the wild. The crested ibis is a success story, yet the species is still in great danger of becoming extinct. Remember the four adult birds (along with their three chicks) whose 1981 discovery in China led to the ultimate rescue of the species? Every crested ibis alive today can trace its genetic roots back to two of those four birds. This has resulted in very, very low genetic diversity for the species. In fact, the ibis has one of the smallest gene pools of any endangered bird. Serious problems are already cropping up as the population grows. Some chicks are born with deformities, possibly owing to inbreeding, and the species as a whole is thought to be more susceptible to disease than it would be if it was genetically diverse. Intense management to try to improve the genetic diversity is now a critical component of the recovery effort.
The growth of the crested ibis population itself creates a catch-22 situation. The larger the population of a species, the more suitable habitat it requires. It was hard enough to ensure the protection of habitat for an isolated population of 7 or even 100 birds, but now there are many times those numbers in the wild. This will probably bring the inevitable conflict between wildlife and the rural people who also depend on the land. In China, conservationists have been spreading the species around, reintroducing it to suitable habitat in diverse parts of the country, trying to avoid having the entire population concentrated in one area. The birds have also been spreading themselves around: in April 2008, a crested ibis was spotted along the southern Yangtze River for the first time in half a century.
All in all, despite the obstacles faced, the resurgence of the crested ibis from practical extinction to nearly 2,000 birds is a conservation success story, though like most others, one whose final chapter has yet to be written.
SEYCHELLES MAGPIE ROBIN
In contrast to a widespread species such as the crested ibis, whose original range may have spanned much of a continent, the Seychelles magpie robin probably never had more than a few dozen square kilometres to call home.
This lovely songbird is neither a magpie nor a robin. It is so named because of its plumage (like a magpie) and its tame, bold behaviour (like the European robin). Found only in the beautiful tropical Seychelles Archipelago in the Indian Ocean, it is the size of an American robin and clothed in black plumage with a dark blue iridescence, with large white patches on its wings. Its song is a jumbled, melodic outpouring, often sung from a tall tree, and its strange call sounds like an electric pencil sharpener. Inhabiting coastal lowland forests across the Seychelles Archipelago, the magpie robin used to follow now extinct giant tortoises while plucking insects, spiders, worms, and even l
ittle lizards from ground disturbed by the passing reptile. A quick study, it learned from its association with tortoises that following other large, slow-moving animals might be profitable, so when humans arrived on the Seychelles in 1770, the tame songbird became a frequent companion. It was commonly found foraging in yards and gardens, even hanging around dinner tables and waiting for scraps of food. The Seychellois, as the islanders are known, came to love their magpie robins. But there were aberrations: in the 19th century, a Frenchman reportedly shot 24 of the birds in one day, a thoughtless act that would have been impossible a century later, when there simply weren’t that many magpie robins left to shoot.
Unlike its two abundant namesake species, the Seychelles magpie robin came close to disappearing for good when it had dwindled to just a dozen birds in 1965. Although much of its forest habitat across the archipelago was earlier destroyed for banana plantations, the biggest culprit for the magpie robin’s drastic decline was predation by introduced house cats and rats.17 Though it once inhabited eight islands in the Seychelles, the species was finally relegated to Frégate Island, a tiny two-square-kilometre privately owned atoll that is known for its exclusive luxury resort. Although the island was cat-free by the 1980s after a successful eradication program, the magpie robins’ situation didn’t improve.
With its tiny population still not growing and being restricted to just one island, a full recovery program run by BirdLife International and funded by the Royal Society for the Protection of Birds began in 1990. Habitat improvements, a ban on pesticide use, cat and rat eradication, the provision of artificial nesting boxes, supplemental feeding, and the control of the introduced barn owl (a predator) and common myna (a nesting site competitor and nest marauder) were all essential pieces of the puzzle to pull the magpie robin back from the edge of extinction.
In 1994, after Frégate’s magpie robin population had experienced a fourfold increase to 48, the first of the reintroductions to other islands began as two birds were translocated to Aride Island. In 2000, the islands of Cousin and Cousine received their first magpie robins. The total population stood at 86, almost double what it was six years earlier. Another six years on and the population had doubled again to 178 birds in total, living on Frégate, Cousin, Cousine, and Aride. In 2007, a watershed was reached when the species was downlisted on the IUCN Red List from critically endangered to endangered, signalling a distinct improvement in prospects that few threatened species enjoy. And the progress continues as the species’ range has been expanded farther to include Denis Island, where 20 birds were successfully reintroduced in 2008–09. Today, about 200 magpie robins exist on five Seychelles islands. Their future is far from certain, however. As a nation of small islands, many of them low-lying atolls, the Seychelles are seriously threatened by sea-level rise caused by climate change. Its beaches have already begun to disappear, being slowly swallowed by the sea. With their already limited area, small islands such as the ones where magpie robins live are especially vulnerable.
NENE (HAWAIIAN GOOSE)
Although they too are oceanic islands, the mountainous Hawaiian Archipelago is fortunate not to face the real threat of disappearance under a rising sea like the low-lying Seychelles Archipelago, the home of the magpie robin. Hawaii’s native biodiversity is among the world’s most severely challenged nevertheless. Yet there have been a few endangered species success stories on the islands (the Laysan duck, Hawaiian coot, and Hawaiian stilt come to mind), none more impressive than that of an unusual goose.
Perhaps it isn’t so ironic that the nene, Hawaii’s official state bird, started life as an immigrant from a cold, northern land. Who can blame the first Canada geese that ended up on that far-flung Pacific archipelago for escaping the nasty winters of their homeland, as many Canadian people do today?
The nene goose (pronounced nay-nay after the Hawaiian word that describes the bird’s soft voice) and four other geese on the islands that have since gone extinct had all evolved from a pair or a flock of the well-known North American birds that somehow made it (perhaps blown off course in a storm) to the archipelago about a half million years ago. They never left. Adapting to empty ecological niches, they evolved into a variety of species over time, including an extinct giant goose that stood 1.2 metres tall and weighed nearly nine kilograms. Today only the nene survives. Despite the passage of thousands of years, the nene remains closely related to the Canada goose genetically. In fact, it is a closer kin than some subspecies of Canada goose are to each other. But you wouldn’t know it to look at it.
Being isolated on an oceanic island with no predators and little competition has had a profound effect on how the species evolved. First of all, because it has exploited the variety of Hawaii’s terrestrial habitats over the millennia, the nene spends less time in water than other geese. Instead, this average-sized goose, with its heavily striped buff, black, and white plumage and distinctive diagonal neck barring spends its time in grasslands, shrub lands, lava plains, and coastal dunes; only occasionally does it use freshwater environments. So, it’s not surprising the nene has lost most of the webbing between its toes (it doesn’t need to swim much), has long, strong legs for manoeuvring on rough terrain, and a more upright posture than other geese for browsing on leaves, grass, fruits, seeds, and the flowers of shrubs and trees. Moreover, living as it does in a tropical paradise where food is available year round, the nene lost the urge to migrate, making it the most sedentary species of goose, with the smallest range.
When Captain James Cook arrived in Hawaii in 1778, the nene was still common, with an estimated 25,000 spread throughout the archipelago, and may have been even more abundant before Polynesians arrived a millennia or so before that. That has changed. Habitat conversion for agriculture and building, hunting, and predation by introduced mongooses, pigs, cats, and rats conspired to decimate the population, which hit a low of just 30 birds by the middle of the 20th century. The nene was poised to follow other native Hawaiian geese species into extinction.
Then, Sir Peter Scott, British naturalist, filmmaker, conservationist, and founder of the Wildfowl and Wetlands Trust (WWT) took up the bird’s cause. In the 1950s, three nene were sent from Hawaii to the WWT facility in Slimbridge, England. After 10 years of careful and intensive captive breeding, the population there had grown to 126 birds. These were sent back to Hawaii to replenish the beleaguered wild population. The slow recovery of the nene had begun. Since then, further captive breeding, both in England and on Hawaii, coupled with habitat protection on the islands, has helped bring the nene back. Today, over 1,500 birds are divided among the islands of Hawaii, Kauai, and Maui. Although the population is a far cry from the handful of birds that remained in the 1950s, several obstacles still have to be overcome to ensure the long-term survival of the species.
Reproductive success in the nene is low, with possibly as few as 10 percent of females successfully rearing offspring. This may be due to the loss of eggs and chicks to introduced predators. Also worrying is inbreeding depression, or low genetic diversity, a phenomenon that occurs after a species passes through a very small population bottleneck (in this case, 30 or fewer individuals, depending on how many of the birds bred). Such a loss of genetic diversity can result in poor resistance to disease and less resilience in adapting to changing environmental conditions. Another concern is road kills, which account for the deaths of a significant number of adult birds.
In addition to the nene that are found in their native Hawaii, a population of captive birds lives half a world away in Wildfowl and Wetlands Trust sites throughout England. Even St. James Park, near Buckingham Palace in the middle of London, has a small resident flock of nenes. The story of Hawaii’s state bird, an erstwhile Canada goose long since transformed, is a qualified success. Though its long-term future is still unclear, it is infinitely better off than it was a half century ago.
BLUE IGUANA
It takes a lot of work and commitment to wrest a species from immanent oblivion: intense planning;
countless hours, days, and months of labour; and money are critical. But it can be done. Perhaps it isn’t too surprising that, so far, all of these success stories are of mammals or birds; after all, they are the most popular kinds of living things. However, on Grand Cayman Island, they have a different favourite.
Best known for its stingrays, sharks, and coral reefs, this Caribbean island boasts of another distinction: it has successfully rescued one of the most endangered reptiles on earth from extinction.
Once abundant, according to fossil evidence, the blue iguana’s numbers began to decline after the arrival of Europeans on Grand Cayman about 300 years ago. By 2003, a scant 5 to 15 of them were all that were left in the wild. The population of the defenceless, meaty lizards was decimated largely by cats, dogs, and rats that arrived with settlers, as well as by habitat destruction as land was cleared for homes, agriculture, and cattle grazing. In more recent times, real estate development has taken its toll. By 2005, the blue iguana was considered to be functionally extinct, which meant its population was too small to sustain itself.
Originally thought to be a subspecies of the Cuban iguana, it wasn’t until 2004, through careful comparisons of the animal’s scales and through DNA analysis, that scientist Frederic Burton established the Grand Cayman animal as a unique species that had long ago diverged from its Cuban cousins. The blue iguana has low genetic diversity, suggesting it may be evolved from a single pregnant Cuban iguana female that was washed into the sea during a storm a few million years ago, only to drift across to Grand Cayman.
With a lifespan that is comparable to human’s—the record is almost 70 years for a captive animal—the blue iguana is Grand Cayman’s longest-lived and largest land animal at a metre and a half long. It can top the scales at a chunky 14 kilograms. Stubby spines run all along its back, giving it an air of dinosaurian ferocity, although like many lizards it is harmless and quite docile. In spite of its name, its skin is usually grey to match its rocky surroundings, but once in the presence of other iguanas, males turn a gorgeous Caribbean-sky blue. Add to this jewel-like ruby and gold eyes and you’ve got yourself one handsome lizard. And there’s something else really neat about these animals: they actually have a third eye on the top of their heads. Not some superstitious ability to see what nobody else can, but an actual eye with a rudimentary lens and retina. Apparently, it may not be able to see that well, but it can detect light and dark and movement—probably not a bad thing to have if you want to avoid being eaten (even though its only natural predator on Grand Cayman is a snake that preys solely on subadult lizards).