100 Under 100

by Scott Leslie

  Even though they spend much of their lives far from the sight of land, every October, at the beginning of the nesting season, breeding-age short-tailed albatrosses, drawn from all over the North Pacific, leave their solitary life of wandering behind to satisfy the urge to reproduce on Torishima, a tiny 500-hectare speck, part of the Izu Island chain, in the Philippine Sea south of Tokyo. They had been doing this for thousands of years on Torishima; millions of them once created a bustling city of brilliant white birds where each pair claimed its tiny patch of ground on which to build a nest, lay, and incubate an egg, then rear its solitary chick. Breeding adults returned every year. New offspring, however, would take to the high seas for up to 10 years before coming home for the first time to breed themselves once they were sexually mature and paired for life with a mate.

  There is going to be trouble whenever a species factors into an economic equation. The short-tailed albatross was no exception to this rule, possessing as it did more than 10,000, soft, airy feathers. The bad news was that people in the United States and Europe needed feathers, lots of feathers, to stuff their mattresses and pillows. The birds were also collected for their meat, oil, and eggs. There is no such thing as an unexploited chance to make a buck, so the short-tailed albatross, which has no defences on its breeding ground (it had evolved over the millennia in the absence of humans and other predators), was clubbed into near non-existence by Japanese feather collectors. Black rats, stowed away on their ships, also invaded the island, adding to the decimation of the bird’s population. During the peak of the exploitation, in the late 19th and early 20th centuries, five million short-tailed albatross were killed in just over a decade and a half. By the 1930s, when a ban imposed earlier by the Japanese government against killing the birds was finally enforced, the population of the species had plummeted to fewer than 50. A decade later it was presumed extinct.

  Then a remarkable thing happened. In the early 1950s, a handful of first-time breeding birds that had been away at sea maturing finally returned home to Torishima to nest. Their reappearance after being at sea for years saved this magnificent species from extinction. By 1954, there were 25 birds on Torishima, including at least six mated pairs.

  Given half a chance, the short-tailed albatross has shown that it has remarkable resilience for a species that was all but extinct. Today, there are nearly 3,000 of them, the great majority returning to Torishima, with the remainder nesting on Minami Kojima, in the Senkaku Islands. Unfortunately, it’s hard to really know what the status of the birds are on this second island, since it lies in a hotly disputed area claimed by Taiwan, China, and Japan since the 1960s and is therefore difficult for scientists to access.

  Despite its brilliant comeback, the North Pacific’s largest seabird is still far from safe.

  Much work has been done to enhance the nesting habitat on Torishima, including revegetation to prevent erosion, the setting of decoys to attract birds to nest in new areas on the island, and designating it as a national wildlife protection sanctuary of Japan to which only scientists are permitted access.

  What’s more, important strides have been made in the past couple of decades to reduce the accidental drowning of albatrosses on longline fishing gear, currently the major threat to their survival while at sea. Brightly coloured banners to deter them from landing near the gear and weighted lines that sink the baited hooks out of the reach of albatrosses have reduced the death toll significantly. In fact, two short-tailed albatrosses killed by longlines in the Bering Sea in late 2010 were the first recorded by the Alaskan Pacific cod fleet since 1998. Of course, this is just one fishery, albeit a large one; however, other North Pacific fisheries are also working to reduce the death toll.

  But there’s one thing nobody has control over. The centre of the short-tailed albatrosses’ universe, Torishima, happens to be the exposed top of an active volcano. Eighty-five percent of the species’ entire population nests on the flanks of an actively seething caldera. In 1902, a violent eruption wiped out the entire population of 125 people who lived on the island. Humans never returned to live there. One hundred years later, in August 2002, another eruption occurred, fortunately at a time of year when all the birds were at sea.

  Nobody knows when the next eruption will be, of course, but if it happens during the nesting season, it would be catastrophic for the species. As insurance against this, a small group of chicks is being translocated to a non-volcanic island in Japan’s Bonin Islands, where the albatross formerly bred. It’s anticipated that the chicks will “imprint” on the island and return there one day to breed as adults, creating a “backup” population free from the threat of volcanoes.

  In 2010, two pairs of the species were also discovered nesting on the US National Wildlife Refuges at Midway Atoll and Kure Atoll in the northwestern Hawaiian Islands. Although it has a long way to go, the short-tailed albatross looks like a species that is determined to once again rule the winds of the North Pacific.

  CAHOW (BERMUDA PETREL)

  A true ocean-going seabird like the albatross, the cahow has been struggling for its survival for more than four centuries now.

  “I have been at the taking of three hundred in an hour … Our men found a pretty way to take them … standing in the rocks or sands by the sea side … making the strangest outcry that possibly they could … the birds would come flocking and settle upon the very arms and head of him that made the sounds, answering the noise themselves … and so our men would take twenty dozen in an hour. There were thousands of these birds and two or three of the islands were full of their burrows.”16

  The abundance of this seabird (named for its haunting call) is evident in this passage written in 1610 by William Strachey, just a year after the British settled Bermuda. The subjects of King James I weren’t the first to discover this diminutive landfall in the North Atlantic, though. The Spaniards beat them to it in 1515. But they were so terrified by the cahow-cahow nighttime calls of a million birds, believing they were demons, that they would never permanently occupy Bermuda. What the Spanish did, however, was release pigs onto the island as a living food store for passing ships. This likely marked the beginning of the end for the cahow, as the porcine invaders overran the breeding colony, collapsing countless nesting burrows underfoot. It’s likely the cahow’s population had suffered a significant decline by the time of British settlement.

  The cahow, or Bermuda petrel, is a medium-sized seabird with brownish-grey upperparts, white underparts, a black cap, and a hooked black bill with external nostrils (a common feature of the “tube-nosed” seabirds, which also include albatross and shearwaters). Sporting long, slender wings a little over a metre across, the cahow is able to navigate through the stormiest North Atlantic conditions. Most of its life is spent at sea, where it captures small squid and fish near the surface. During the January-to-June breeding season, it will fly hundreds of kilometres over the ocean during the day to capture food to bring back to its nesting mate and single chick at night, under the cover of darkness.

  By 1614, escaped rats from arriving ships had become a plague on Bermuda. The exponentially multiplying rodents devoured the eggs of seabirds, including the cahow’s, adding to the already serious damage caused by the pigs brought earlier by the Spanish. Moreover, the rats ate all the crops, leaving the starving people of the island with no choice but to eat seabirds to survive. In just a decade or so, the cahow’s population plummeted from hundreds of thousands to nearly zero: it was thought to have disappeared by about 1621, earning it the dubious distinction of being one of the first extinctions in recorded history. Or so it was thought.

  During World War I, after it had been “extinct” for about three centuries, a Bermudan naturalist found a bird he claimed was a cahow. At the time, nobody seemed to pay him any mind; there was a war on, after all. Then, in 1935, a mysterious bird was discovered dead on the ground at the foot of the lighthouse on St. David’s Island, at the eastern end of Bermuda. It was sent to American Museum of Natural Histo
ry ornithologist Robert Cushman Murphy in New York, who confirmed it as the long-lost cahow. The prodigal seabird had returned. But where did it breed? That question wouldn’t be answered for another 16 years. In 1951, Murphy; Louis Mowbray, naturalist and founder of the Bermuda Aquarium; and a 15-year-old Bermudan boy named David Wingate found a tiny colony of 18 pairs nesting on barren rocky islets in Castle Harbour at the eastern end of the island. The nesting territory was tiny, covering barely a hectare. The breeding cahows had somehow gone about their business while eluding detection for all those centuries, even though they were within just a few kilometres of several villages.

  The 1951 discovery had a profound influence on the young David Wingate. After returning from Cornell University in 1958 with a freshly minted ornithology degree, he began to work full time for the critically endangered seabird. He held the official post of conservation officer for the Bermuda government from 1966 until his retirement in 2000.

  Special nesting burrows were constructed on the cahows’ islets, and partial covers, known as baffles, which restricted the size of the openings, were placed at the entrance to the existing nest cavities to prevent larger white-tailed tropicbirds from taking the sites. Rats were removed and native vegetation was planted on the breeding islets as well as on other potential nesting islands. The number of breeding cahows began to grow, but their islet colonies offered very limited room for the expansion of the species’ population.

  In pre-colonial times, cahows nested all over Bermuda in burrows they dug in the soft soil of the forest floor, but any restoration of former breeding habitat on the main island was impossible. It was simply too developed and too populated to be an option. Nonsuch Island, located at the eastern entrance to Castle Harbour, however, had potential. At six hectares it was much larger than the islets the breeding birds were confined to. When David Wingate moved there to live in 1962, it was a barren rock. A disease had earlier killed the native cedar trees, and introduced pigs stripped it of the rest of its vegetation. Wingate’s goal for the island, which he dubbed the “Nonsuch living museum,” was to restore it to its pre-colonial ecological state in preparation for the reintroduction of the cahow. After decades of work, Wingate and his family removed introduced plants and animals, planted 100,000 trees and shrubs on the island, and restored freshwater ponds and a salt marsh. Nonsuch hadn’t seemed so natural in centuries.

  All the work spearheaded by Wingate is paying off. The cahow is really and truly coming back to Bermuda. Breeding success has gone from 5 percent in the 1950s to 50 percent in 2010. The nesting islands in Castle Harbour have become a national park. Over 100 fledgling birds were translocated to Nonsuch Island between 2005 and 2008, four decades after Wingate began restoring it. In 2009, the first cahow chick in nearly 400 years was born on the island and a new nesting colony had taken hold. By 2010, there were a total of 95 breeding pairs, plus scores of non-breeding cahows throughout Bermuda.

  Yet, despite its success, the species is still highly endangered. A large unknown is the effect climate change and more severe hurricanes will have on nesting sites. For the first time in living memory, the islets were flooded during recent hurricanes. Fortunately, it happened during the non-breeding season when no cahows were present. Although the species ranges across a vast swath of the North Atlantic, from the North Carolina coast to the Azores, it appears to spend most of its time gathering food in or near the Gulf Stream. Some oceanographers predict the Gulf Stream will weaken as more and more cold water from melting Arctic ice disrupts it. What effect will this have on the distribution of marine life in the world’s most powerful ocean current? Will it result in a decline in food availability for seabirds in the North Atlantic? And how would this effect a species like the cahow that still sits at the edge of extinction?

  CHATHAM ISLAND BLACK ROBIN

  Like the cahow, the recovery of the Chatham Island black robin is one of conservation’s most celebrated triumphs. Not long ago, this sparrow-sized bird was considered by most biologists to be functionally extinct, meaning its disappearance was all but inevitable. Fortunately, some refused to accept such a verdict for the species.

  In the 1970s, the entire population of black robins lived on Little Mangere Island, a small sea stack in the Chatham Islands about 1,200 kilometres off the coast of New Zealand. By the 1800s, the species had been wiped out in the rest of the island chain by cats and rats that arrived with European settlers. But Little Mangere was uninhabited and surrounded by 200-metre-high cliffs, so introduced predators never made it there. But the island was a prison, too. With a dying forest and a harsh climate, the birds were unable to thrive. And, the catch-22 was that evolving in an environment where strong flight to evade predators wasn’t needed meant their wings were too weak to carry them off the island to another place to live.

  In 1972, this remnant population was discovered by Don Merton, a New Zealand biologist and conservationist. There were only 18 birds left. Keeping a close eye on the fate of the hapless species, Merton continued to return to the island, watching the population dwindle to only 7 birds by 1975. Something clearly had to be done. So, in a risky last-ditch effort, Merton and his small team relocated the remaining few birds to two larger islands with better habitats—and hopefully a better chance at survival. However, this didn’t seem to help, and the species continued its slump toward extinction.

  By 1979, the fate of the black robin rested on the tiny wings of the sole breeding female, named Old Blue, plus three males and a non-breeding female. It also weighed on the shoulders of Merton and his helpers. At this point, the bird’s survival must have seemed hopeless, but both birds and humans refused to give up.

  Merton decided to take drastic action: when the lone female robin laid her eggs, they would be moved to the nests of other birds— abundant Chatham Island tits, to be precise—so that these surrogate females would incubate and hatch the robin’s eggs as their own. Why? It is well known that many songbirds will lay a second clutch of eggs if the first is lost. So it was hoped that taking Old Blue’s first clutch of eggs would force her to lay another. Indeed, she did lay a second clutch and hatched them. But what to do with those baby robins that were being reared in the nest of the surrogate Chatham Island tits? They were put back into the black robin’s nest and added to the young from her second clutch—the ones she hatched herself—to double her family size. To help feed all these extra mouths, Merton and his team provided additional food to supplement what was being brought by the parents. It worked. This proved to be a successful strategy for the Chatham Island black robin.

  Today, they number around 250, living on South East Island and Little Mangere Island, all of them descended from that lone female. The technique of placing the eggs of one species with a surrogate of another to increase the number of clutches laid is known as cross-fostering. It has since been emulated around the world in the recovery efforts for other species of endangered birds.

  Old Blue lived for an amazing 13 years—that’s twice the normal lifespan of the species. She may have been the saviour of her kind, but she couldn’t have done it without dedicated conservationists, especially Don Merton, who would go on to play an important role in other endangered species success stories, including that of one strange parrot.

  KAKAPO

  Think of a parrot. What comes to mind? If it is a squawking, brilliantly coloured bird perched in the midday sun on a branch eating a piece of fruit in the tropical jungle, you’d be right. But there are a few parrots that are distinctly different from that stereotype, and New Zealand’s endemic kakapo is one of them. A Maori word for “night parrot,” the kakapo is the most unusual species in a spectacular family of birds. How unusual? It is heavier than any other parrot. It is flightless and lives largely on the ground. Its face is as much owl-like as it is parrot-like (in fact, the kakapo’s genus name is Strigops, from the Greek strix for “owl” and opsis for “face”). It is also commonly known as the owl parrot—a name that’s even more suitable considering its noct
urnal habits. If all that isn’t enough, it’s one of the longest-lived animals on the planet, reaching 100 years or more.

  The ancestor of the kakapo arrived in New Zealand thousands of years before humans came on the scene. With the exception of a few species of bats, there were no mammals there at the time, so the kakapo eventually became flightless to fill an ecological niche that would have been occupied by a similarly sized herbivorous mammal. The species flourished in this environment and lived on both the North and the South Islands, as well as on Stewart Island. The abundance of fossils indicates that at one time it was New Zealand’s third most common bird. Their cryptic green plumage made them exquisitely adapted for hiding among the vegetation to avoid the only predators they had: four species of raptors and the laughing owl. But evolution, as effective as it is in adapting life to its surroundings, needs time to do it. Things began to change too rapidly for the kakapo to keep up its defences once the first humans arrived around AD 1000.

  Not only did the Maoris hunt them for food, skins, and feathers, the dogs they brought with them made short work of the kakapo, a bird with a very strong scent (easy to locate), a habit of freezing rather than fleeing when danger threatened, and an inability to fly (easy to catch). As well, the Polynesian rats that also arrived with the Maoris decimated kakapo eggs, which were laid in ground nests.

  The species had already been wiped out across most of its former range by the time Europeans landed in the 1800s. Massive clearing of forests for timber and agriculture, hunting, the introduction of weasels and ferrets (a misguided effort to reduce an overabundance of introduced rabbits), feral house cats, and specimen and egg collecting for zoos, collections, and museums drove the kakapos’ numbers perilously low.