by Scott Leslie
The pristine subantarctic outlier wasn’t prepared for the rodents that jumped ship and tucked into the virtually limitless supply of food offered by Campbell Island’s virgin ecosystem. Rats may have poor eyesight, but their keen sense of smell was all they needed to sniff out the nests and consume the eggs and young of the thousands of birds that inhabited the island. With no predators of their own and abundant food, the rapidly reproducing rats multiplied into the hundreds of thousands. Known as the albatross capital of the world, Campbell Island is home to six species of the giant oceanic wanderers, including the bulk of the planet’s breeding southern royal albatrosses. They, along with storm petrels, became fair game for the marauding army of rodents. Fortunately, though severely affected by rats, these seabird species were also found on other islands, so none of them were threatened with extinction.
It was a different story for the Campbell Island teal, a bird which was much less abundant and, most importantly, found nowhere else—if they were wiped out here, they were gone everywhere. The rats wreaked havoc on the eggs and young of the endemic duck, which over time became rare, almost unto oblivion. The last teal on Campbell Island was observed in 1944. By everyone’s lights it became extinct. Then, in 1975, a tiny population of just 20 ducks was discovered on Dent Island, a small islet sitting three kilometres off Campbell’s coast. The rat-free 23-hectare chunk of rock was the final refuge for the flightless duck. Despite there being only a handful of them, the Dent Island birds represented an opportunity to eventually restore the species to its former stronghold on nearby Campbell Island.
It was crucial to ensure that those birds left on Dent Island survived as a reservoir to seed a future comeback of the species. So seven males and four females caught there in 1984 and 1990 by the New Zealand Department of Conservation were taken to begin a captive breeding program at the Pukaha Mount Bruce National Wildlife Centre on the mainland. In 1994, the first Campbell Island teal ducklings were born in captivity. Eventually, the program was successful enough that 24 birds were released on Codfish Island in 1999 and 2000. Much closer to the New Zealand mainland, Codfish Island was initially meant as a temporary home for the teal while its population grew, since the island’s rats, cattle, sheep, and feral cats had already been removed to protect the kakapo, a critically endangered flightless parrot. The ducks quickly became established on the island, enjoying a high survival rate. As the new millennium dawned, with a healthy population of Codfish Island birds, plus the captive ones at the national wildlife centre, it was decided that the reintroduction of the Campbell Island teal to its namesake island would be feasible. It would have to wait a little while longer, however; before even a thought could be given to reintroducing the birds back to Campbell Island, the problem of the rat hordes would have to be fixed.
So the final crucial step was to get rid of the thousands of rats on Campbell Island. In the largest rodent-eradication campaign ever undertaken anywhere, the winter of 2001 saw over 120 tonnes of rat-specific poison bait dropped on the island from helicopters. It was risky work, given the brutal winds that blow in the subantarctic at that time of year, but the job was successfully completed. By 2003, Campbell Island was declared rat-free. Since then, over 100 teals have been reintroduced to the island. Although not all of the ducks survived, they have re-established themselves and are beginning to breed. Estimates put the current wild Campbell Island teal population at between 48 and 100 birds, including the Dent Island and Codfish Island populations, not to mention additional captive birds that are still part of the breeding program. Population growth has been slow but steady. In 1975, only 20 Campbell Island teals remained on earth, isolated on tiny Dent Island. Today, though still endangered, they live and breed on three islands: a huge step in the right direction. The future beckons for the little flightless duck.
MADAGASCAR POCHARD
Unlike its flightless New Zealand cousin, the more typical Madagascar pochard duck possesses the power of flight, though this has been of little help in fleeing the effects of a burgeoning population on the world’s fourth largest island.
With most of its 21 million people being poor and rural, much of the country’s natural riches have simply been cut down or plowed under. Nowhere has been more affected by this rising tide of humanity than Lake Alaotra and its environs, located on the island’s Central Plateau, north of the capital Antananarivo.
The largest body of water in Madagascar at 900 square kilometres, the lake and its surroundings are the breadbasket of a country struggling to feed itself. More rice and freshwater fish is produced here than anywhere else on the island. Ever more of Alaotra’s watershed is converted from natural habitat into agricultural use to feed the burgeoning populace. And the lake itself is literally disappearing as decades of deforestation on the surrounding hills have laid bare their soils, countless tonnes of which has been simply washed into the water by erosion. Despite covering an area about six times the size of Washington, DC, Lake Alaotra is literally being filled in by soil. Nowadays, it is a mere 60 centimetres deep during the dry season. Of course, a shrinking body of water is big trouble for the ecosystems and animals that depend on it, and many of the species that live here are threatened with extinction. Even non-aquatic animals such as the Alaotra gentle lemur, which inhabits what is left of the surrounding forests and is found nowhere else, is endangered.
But habitat destruction is only the beginning of Lake Alaotra’s problems. Of the more than 20 species of introduced, exotic fish that have become established in Madagascar’s fresh waters over the years, none is more menacing than the Asian snakehead. This large, aggressive, eel-like fish has a huge mouth and sharp teeth for snatching and swallowing its prey whole. It was deliberately and foolishly introduced to the island in 1976 as a potential food fish, a personal initiative of Madagascar’s then president, Didier Ratsiraka. Once released into the environment, the fish spread like a plague across the island, invading lakes, streams, ponds, and wetlands, all of whose native species hadn’t evolved to deal with such an aggressive predator. Its spread was virtually impossible to control as it used its ability to breathe air directly and leave the water to slither like a snake through the mud during the rainy season to reach new lakes and ponds.
The snakehead’s nasty disposition has already resulted in the extinction of three native Madagascar fish species and one of its birds, the Alaotra or rusty grebe. This little wetland bird, found exclusively on its namesake lake and nowhere else, was already declining rapidly due to rampant habitat destruction by the time the snakehead arrived. The hungry fish simply finished the job by sneaking up from below to snatch the grebe’s tiny chicks, stealing an entire generation in a few gulps. This was the last straw for the hapless endangered bird. It had finally succumbed, declared officially extinct by the IUCN in 2010. The Alaotra grebe will never be seen again.
A similar fate almost befell the Madagascar pochards that lived in Lake Alaotra. Still quite common on the lake in the early part of the 20th century, their number had plummeted by 1991, when a single male bird was captured and taken to the Antananarivo botanical garden. It died a year later. That was the last pochard ever to be seen on Lake Alaotra. Extensive searching of the lake—the only place it was known to exist at the time—throughout the 1990s right up until 2001 failed to locate even a single bird. Given the lack of evidence for its existence, the inescapable conclusion was that it was gone for good. In 2006, the IUCN listed the duck as possibly extinct. Fortunately, that wasn’t the end of the Madagascar pochard’s story.
A medium-sized, brown duck, the Madagascar pochard is closely related to familiar northern hemisphere species such as the ring-necked duck and the canvasback of North America and the common pochard of Europe. Like these other members of the genus Aythya, it is a diving species, gathering small invertebrate animals, vegetation, and seeds from the bottom of its shallow freshwater habitat. Non-migratory, it breeds from October to January, laying six to eight eggs in a nest built among the grass and reeds that grow
in the shallow waters around lakes. Little else is known about its life cycle or natural history.
In late 2006, while searching for the endangered Madagascar harrier in a remote area 300 kilometres north of Lake Alaotra, Lily-Arison Rene de Roland of the Peregrine Fund and biologist Thé Seing Sam discovered a group of nine adult Madagascar pochards and four recently hatched chicks on a small lake. By a quirk of geology, the steep shores of the volcanically formed body of water weren’t suitable for rice production, so there was little human disturbance to the ecosystem. And just as importantly, it didn’t contain Asian snakeheads or other fish that preyed upon young ducklings.
The rediscovery of the “extinct” pochard made headlines around the world. Subsequent investigations have revealed a population of 20 to 25 birds. The pochards also visit other lakes in the area but do not breed there. Of course, such a small population is hardly sustainable, and a single event, such as poaching, a disease outbreak, or a pollution spill, could easily wipe out the species.
Today, several conservation organizations are working along with the government of Madagascar to save the pochard. The priority is to protect the few remaining birds from hunting and other direct human disturbance, so the site is now permanently guarded. But that’s not enough. Conservation groups are garnering support from local people in an effort to have the pochard’s habitat legally protected as a sanctuary. Low hatchling success has been observed since rediscovery in 2006. Not a single young survived in 2008, despite nesting attempts by six pairs of adults. So the following year, a few eggs were strategically removed from nests to be carefully hatched under controlled conditions. This was successful and led to the first captive-reared Madagascar pochard ducklings. The species needs such help if it is to grow in numbers. As a crucial step toward its restoration, plans for a lakeside breeding facility are in the works. Of course, there’s always the possibility the Madagascar pochard could be found inhabiting as yet unsearched lakes and wetlands. And, as much as the odds are stacked against it, if enough suitable habitat can be restored at Lake Alaotra, the Madagascar pochard might one day return to the epicentre of its former range—something that seems unlikely for a grassland bird living on the other side of the world. The centre of its former range is now occupied by the city of Houston, Texas.
ATTWATER’S PRAIRIE CHICKEN
Long ago, before centuries of habitat destruction and intensive overhunting, there may have been a million Attwater’s prairie chickens spread across almost two and half million hectares of bluestem Indiangrass and switchgrass prairie along the west coast of the Gulf of Mexico. This subspecies of the greater prairie chicken once had a range that stretched all the way from Corpus Christi, Texas, north to Louisiana. Today, all but less than 1 percent of its habitat has been lost to agriculture and urban development (the sprawling city of Houston is located smack in the middle of what was once prime prairie chicken habitat). Many of the habitat scraps that remain are too small to be of much use to wildlife, and even on the larger patches, fire suppression has changed the natural vegetation cycles, resulting in the growth of scrubland unsuitable for the bird to thrive in. Add to this overhunting and you wind up with one of the most endangered birds in the United States.
Prairie chickens belong to the same order of gallinaceous birds as the wild predecessors of the domestic chicken. They also look like them. Today, two species, the greater and the lesser prairie chickens, are found from North Dakota to the Gulf Coast of Texas. Both have experienced serious population declines over the last several decades. The greater prairie chicken had disappeared altogether from the northern edge of its range by 1987 and is now extinct in Canada. The Attwater’s, the most southerly of all the prairie chickens, hangs on by the thinnest of threads.
Facing extinction is nothing new for prairie chickens. The heath hen, a separate subspecies of the greater prairie chicken, once lived along the Eastern Seaboard of the United States. It is thought that the Thanksgiving “turkeys” eaten by the Pilgrims were, in fact, heath hens. The subspecies used to be so abundant on blueberry barrens and coastal grasslands from Virginia to New England that it was part of the daily diet in many places—so much so that apparently people were sick of eating them: 18th-century live-in house servants in Boston demanded they not be fed heath hens more than three times a week. But this close cousin of the Attwater’s prairie chicken was ultimately doomed. There may have been millions of them flourishing on coastal grasslands when the Pilgrims arrived. Moreover, they had been legally protected since 1791, when the first law against killing them during the breeding season was enacted in New York State (in fact, it was the first wildlife protection law to be enacted anywhere in the United States). But it wasn’t enough. Habitat destruction and hunting did them in. The last heath hen, a male nicknamed “Booming Ben,” survived alone for three years in a sanctuary on Martha’s Vineyard, Massachusetts, until finally succumbing in the winter of 1932. He was one Chicken Little whose sky did fall. The question is, will we do a better job of saving another threatened prairie chicken?
About the size of a domestic bantam chicken, with a length of about 45 centimetres and weighing up to almost a kilogram, Attwater’s prairie chicken is distinguished by fine vertical banding of dark brown and buff feathers covering its lower body. Males have long tufts of feathers on the back of their necks that can be raised vertically like horns during courtship and possess two orange-yellow, inflatable throat sacs. In winter, the birds gather on leks or booming grounds located on rocky outcroppings or where the grass is especially short. Here the males will perform a dance in front of the females to attract a mate. Raising their tufts and inflating their throat sacs, they produce a booming oo-oo-oo call, which sounds like air being blown across the mouth of a jug. All the while, with heads down, wings drooping, and tail erect, males stamp their feet in quick staccato, turn in circles, and occasionally jump into the air before charging at other males.8 When a female prairie chicken sees a dancing male she’s particularly impressed with, she’ll choose him as her mate. She’ll breed with him, then go off on her own to a spot on the prairie, build her nest, and lay a dozen or so eggs. She’ll incubate them for nearly four weeks. If fortune favours her and the nest isn’t raided by skunks, snakes, coyotes, racoons, or feral cats, there will be a big brood of new chicks to rear for the next six weeks, during which time she’ll be on constant alert for hungry hawks and owls. It is an uphill battle.
In spite of the bird being listed under the US Endangered Species Act since the early 1970s, only 75 to 90 of them survive in the wild in three places: Attwater Prairie Chicken National Wildlife Refuge west of Houston, Texas City Prairie Preserve near Galveston, and at a private ranch in the Goliad prairie area north of Corpus Christi.
The population isn’t small for lack of trying, though. The bottom line is that were it not for human intervention, Attwater’s prairie chicken would be extinct. Although humans are responsible for their decline, we have also thrown them a lifeline in the form of captive-bred birds that continually replenish the small wild population. From modest beginnings when the first captive birds were hatched in 1992 at a private wildlife centre, they are today reared at five zoos and a university. Each captive-bred flock of Attwater’s prairie chickens contributes to a pool that is used to boost the number of birds in the wild. Out of reach of predators, young prairie chickens are placed temporarily in protective enclosures surrounded by wild prairie. Once they are acclimatized to their natural habitat, they will be turned loose into one of the three sanctuaries, where they’ll have to survive on their own. Although hundreds of captive-bred birds have been released this way, mortality—especially by birds of prey—is extremely high, so population growth in the wild is painfully slow.
The US Fish and Wildlife Service’s recovery goal for the Attwater’s prairie chicken is to eventually have 5,000 birds in three self-sustaining, geographically separate populations. If this is to be achieved, and if the population is to rebound beyond even this, we will need to overcome th
e most difficult challenge of restoring enough suitable native habitat—no small feat when you consider that less than 1 percent of it remains. It will no doubt take the protection of the Endangered Species Act, plus commitment on the part of government, conservation organizations, and private landowners if the Attwater’s prairie chicken is to have a real fighting chance for a long future.
PUERTO RICAN AMAZON
By dint of Puerto Rico’s status as a US territory, this parrot too is fortunate enough to be protected under the four-decade-old US Endangered Species Act. To understand how crucial such laws are for the survival of species, and perhaps even how we’ve evolved as a society, we need to look at what happened to another American parrot species a century ago.
Once found in the millions from the Gulf States to Ohio and even southern Ontario, the Carolina parakeet was a noisy, brilliant green, yellow, and orange bird that was done in by its own abundance and hunger. Because it turned to farm crops to survive after millions of hectares of its forest habitat were cleared, the small grackle-sized bird was slaughtered as a pest by farmers. It was also a victim of the millinery trade, the despicable 19th- and early-20th-century industrial killing of birds for feathers to decorate hats. The last Carolina parakeet in captivity died in 1918 at the Cincinnati Zoo in the same cage that Martha, the last passenger pigeon, had died four years earlier. The moral of the story? Without legal protection, it took only a matter of decades for two of the continent’s most abundant birds to disappear. The same fate almost befell the Puerto Rican amazon. Also known as iguaca by the island’s original Taino Indians, it is one of the most critically endangered parrots in the world. The 50 or so remaining birds are the last survivors of ancestors that were thought to have arrived from South America eons ago.