Fence Me In
Ka’ena Point, Oahu’s wild and windswept northwestern tip, is the ancestral gathering place for souls of the dead, from where they jump off into the next world. Now it has new resonance as the first piece of land in Hawaii that is being allowed to revert to the way our islands were thousands of years ago, when there were no people, the only mammals were seals and bats, and tens of millions of seabirds flocked in from all over the world to nest. Kaena is now a global focus as the last hope of saving this rapidly diminishing bird species.
That hope is crystallized in nothing more complicated than a green fence, six and a half feet tall, that stretches 2,000 feet across the Point in a north-south zigzag pattern. It contains three double-door, unlocked gates that force people to close the back door before opening the front one. What makes the fence special: an overhang that allows animals to climb out, but not in; a skirt that prevents their burrowing underneath; and a mesh so fine, even baby mice can’t get through. It is one of the first fences aimed at protecting seabirds to be built outside of New Zealand, where they were pioneered to save the kiwi, and the first one in America.
After the barrier was completed, in March of last year, biologists used poison and traps to eliminate, from the 59-acre zone of dunes and low bushes, the mongooses, rodents, feral cats and dogs that preyed on the eggs and chicks of Oahu’s biggest colony of moli, the majestic Laysan albatross with a wingspan of seven feet, and ‘uau kani, the smaller wedge-tailed shearwaters on whom fishermen depend to tell where the tuna are feeding. These once gathered in Hawaii in the tens of millions, but today, only about 100,000 show up every year.
The fence has already yielded a 15 percent increase in the number of albatrosses, about the proportion of chicks that were previously killed by predators. The increase in the number of shearwaters remains unclear because they’re hard to count–they leave their burrows before dawn and return at dusk–but the number of chicks that flew off last year tripled to 1,775. “They were being decimated by the rats because they’re much smaller,” says Eric Venderwerf, one of two biologists studying the colony.
Unlike their continental cousins the seagulls, blue-water or pelagic, seabirds spend most of their lives at sea. They return to land only to nest, usually on the ground, on oceanic islands that used to be free of mammals–some as large as Hawaii or New Zealand, others mere islets. When Polynesians began fanning out across the Pacific two millennia ago, they feasted on the birds, which had no innate fear of predators and remain, even today, easy to catch. “The kitchen middens had more seabird bones than any other kind of animal except shellfish,” reports Helen James, curator of birds at the Smithsonian Institution in Washington, D.C., and a Hawaii specialist.
Species not prized by people were quickly decimated by dogs and rats they brought with them. As a result, nesting colonies were found only on smaller and remote islands.
Then came the Europeans, who slaughtered millions of seabirds for the feathered-hat trade and introduced cats, mongooses and bigger rats to the islands.
Meanwhile, the postwar development of industrial fishing accelerated the birds’ decline, which a just-completed study by the University of British Columbia estimates at 25 percent–about 250 million seabirds–since 1950, according to co-author Michelle Paleczny.
Another study published this year reports that 75 percent of threatened pelagic seabirds species are affected by invasive predators where they nest, while 41 percent suffer losses when they drown after being snagged while trying to snatch baitfish from hooked lines set out by tuna boats. “They’re diminishing faster than other birds because they’re hit both where they feed and where they nest,” says co-author Stuart Butchart, Global Research Coordinator at BirdLife International of Cambridge, England.
A recent study in science found that populations of seabirds that depend on small fish like anchovies and sardines tend to shrink when the biomass of the fish populations falls below one-third of its pre-fished size. “Given that most commercial fish stocks are exploited far beyond that level, a lot of seabirds are effectively being starved,” says lead author Phillipe Cury, director of the Mediterranean and Tropical Fisheries Research Center in Sète, France.
On the hopeful side, the Smithsonian’s James points out that, for pelagic birds, falling population numbers are rarely followed by extinctions. In Hawaii, for instance, while the fossil record shows that there were 107 species of birds before Polynesians landed, only two among the 77 species that are now extinct are seabirds. “Seabirds have choices, they can nest somewhere else,” James explains. “And they can rebound quite fast.”
Midway, in the Northwestern Hawaiian Islands, is a case in point. When the American military started fortifying it in 1940, more than 500,000 Bonin petrels were showing up to nest, says Beth Flint of the U.S. Fish and Wildlife Service in Honolulu. But accidentally-introduced rats reduced the petrel population to 5,000. Less than two decades after the rats were eradicated, more than 300,000 Bonin petrels fill the evening skies. Meanwhile, the albatross colony grew to 1.5 million birds, now the largest in the world. The density is 1,000 birds per acre, making nesting season a breathtaking spectacle.
The birds have perfected the art of flying just above rushing waves while barely moving their wings, even literally sleeping on the wing. But on land they have the gait of a toddler with flippers, and they are atrocious navigators in crowded spaces. One day on Midway, an albatross knocked me down a fraction of a second after it flew into my frame as I was taking a picture.
Killing falls short
Eradications of invasive predators, which range from yellow crazy ants to macaque monkeys, have taken place on more than 300 islands since the 1970s. “The rats are still the biggest killers,” says Alex Wegmann of Island Conservation, an organization based in Santa Cruz, Calif., that specializes in eradications. Unfortunately, Wegmann notes, eradications have reversed the decline of only a handful of species.
The big problem is that by now, most of the easiest islands have been eradicated. “The ones that are left and that have a lot of endangered species, like Gough and South Georgia in the Atlantic, are bigger, complicated and they’re going to be more expensive,” Wegmann says.
The Kaena solution
The future lies with the Ka’ena Point model, with other slices of large islands such as Fiji, the main Hawaiian islands or New Zealand that can be fenced in. In the case of Kaena, the model is affordable and costs as little as $290,000. “Seabirds rebound much faster than other birds because immigration is added to reproduction,” says Tim Day of Xcluder of Rotorua, New Zealand, the company that built the Hawaii fence. “It’s like taking the handbrake off when you’re driving.”
As a result, Lindsay Young, who did her Ph.D. at the University of Hawaii on the Ka’ena albatross colony, says it could theoretically grow to more than 10,000 birds. “I certainly expect it to reach 1,000 in 10 years,” she says.
One advantage of the fences over remote-island extirpation is that funding is easier to obtain, Day says. The predator-free zones can be set up near human habitations like Ka’ena Point, which has now become the world’s only easily accessible and unsupervised albatross colony–just 30 miles from the Aloha Tower–because the popular support is there.
For scientists, it’s even better than that: the 400 albatrosses in Ka’ena are becoming one of the most closely monitored colonies in the world, with virtually every bird wearing ID rings. Some have GPS locators that show where they fly in the North Pacific to feed on squid and small fish while their partner watches the chick. This level of detail is impossible to achieve in Midway because there are so many birds there, scientists say.
It’s this kind of data, points out Sheila Conant of the University of Hawaii, that allowed Young and a colleague, Branda Zaun of the FWS, to make the discovery a few years ago that about one-third of the nesting pairs of Laysans at Ka’ena–many have been paired for years, even decades–are females (both sexes look alike). It was the biggest proportion of any known bird colony and sparked a national debate on homosexuality, complete with a grave warning from Stephen Colbert that “albatresbians” were threatening American family values with their “Sappho-avian agenda.”
Like most points, Ka’ena (which means really hot) is the gateway to excellent fishing. Several platforms suggest there were shrines to fish deities and perhaps even villages. In 1897, the narrow-gauge line of the Oahu Railway and Land Company was built running westward from Kahuku, the far eastern end of the North Shore, and curling right around Kaena Point to Honolulu, for what must have a been a spectacular trip. It ran until it was damaged by a tsunami in 1946. Both access roads to the point follow the old tracks, with some wooden ties still visible.
The Kaena Point Natural Area Reserve was established in 1983 to protect a portion of the biggest dune system left on Oahu from degradation by off-road vehicles, but drivers largely ignored it. The area began to heal only in 1990, after erosion washed away part of the southern access road and an excavator was hired to place a dozen boulders blocking the northern path.
Within a couple of years, the shearwaters and the albatrosses established nesting colonies. The state started a trapping and shooting program for predators, culling an average of 13 cats and 43 mongooses a year. Rats were poisoned.
Things would have stayed that way if, the FWS hadn’t thrown in the towel in 2006 on an attempt to build a similar fence in South Kona to protect habitat for the ‘alala (Hawaiian crow). The agency had already received the money for the fence, but concluded that lava tubes in the rough terrain would make predator-proofing a long and difficult process, according to Jeff Burgett of FWS.
Just at that time, a pack of feral dogs went on a rampage in Kaena Point, leaving more than 100 shearwaters dead, while cats killed some more inside their burrows. The publicity helped persuade the agency to reallocate some of the fence fund to the Hawaii Department of Land and Natural Resources (DLNR) to build the fence at Ka’ena, which would end both the killing of birds and the state’s expenses in killing predators there.
The same year, Young, the biologist, and Vanderwerf, her husband, founded a company called Pacific Rim Conservation, which sought the contract to manage the project, proposing to supervise the acquisition of the required permits, the building of the fence and the program to monitor effectiveness.
In preliminary hearings on the project, some native Hawaiians, led by a cultural practitioner named Summer Nemeth, challenged the fence, arguing that the site was too sacred to permit anything to be built there. On the Carroll Cox radio show, Nemeth accused Young of “acting in a very culturally insensitive way” and being motivated by “clearly, profit.” All other written and oral comments on the project were positive, according to the official final report.
Nemeth’s challenges delayed the project by two years, and resulted in the addition of a third gate in the middle, along a line between a fishing shrine lying outside the fence and Leina a ka ‘Uhane, the Soul’s Leap, a slab of coral lying by the shore about 1,000 feet east of the point and halfway between the point and the fence.
The report adds, “Some stakeholders have indicated that having the Leina a Ka ‘uhane within the fenced unit would prevent souls from coming down from the mountain and leaping off into the next world, while other stakeholders indicated the fence would not be a problem because souls can move easily through barriers.” The unlocked gate can be seen as a compromise, showing spirits, as well as living beings, that there is no intent to impede their free passage.
Having been awarded the contract, Young and VanderWerf went to work as soon as the barrier was in place. Within six weeks, the main killers–cats, rats and mongooses–were either trapped or poisoned. Mice, which mostly affect native plants, took another six months. Last spring, scores of bushes of one of our prettiest native flowering plants, the ‘ohai pea with its delicate vermillion flower, are sporting an exceptional number of pods. It’s the first time in centuries that most of the ‘ohai’s seeds were not devoured by rats, promising a renaissance next year.
Healing the whole
The fence is showing, for the first time in Hawaii, how a whole ecosystem can recover once it’s fully shielded from non-native predators. How will the eleven endangered native plant species fare, not to mention uncounted species of bugs? Tim Day of New Zealand says when rodents are eliminated, some native bugs thrive and attract birds. Will other seabirds in search of safe nesting places, such as the dark and handsome black-footed albatross, the fast-moving Koa ‘e ‘ula or tropic bird show up? Will native land birds, like the pueo or Hawaiian owl, follow?
I asked Lindsay how she felt about killing the cats and mongooses caught behind the fence. “Until the fence was built, the state was removing cats and mongoose every year–about 150 cats in 10 years, and almost 500 mongooses,” she replied. “There probably weren’t more than a handful inside after the fence was built, and a couple of cats. Meanwhile, Eric and I were the ones who were picking up most of the dead birds, usually two or three a week. Now all the killing has stopped — and I don’t just mean the predators, but also the hundreds of chicks that they were killing every year. That’s pretty satisfying,” Lindsay concluded.