Rat Island (13 page)

Inevitably the games of hide-and-seek and play fighting would end. Kaukeinen would be forced by protocol to proceed to the final step of the experiment, adding to the innocuous baits the lethal dose of brodifacoum. He hated the death. He had come to see in his adversary a soul of admirable wits and resolve. To quiet his conscience, he reminded himself that this was a creature whose kin, the black rat, had once carried the fleas that had carried the bacterium of bubonic plague, which four centuries earlier had swept a third of humanity to horrific death. He kept in mind, as he killed, that this was the rat whose kind was even now eating a fifth of the world's crops, adding filth to his country's foodstuffs, biting and sometimes maiming thousands of his cities' poverty stricken. He had seen, in his own country, homeless people and kids in cribs with toes bitten off. He was reminded daily of the rat's ferocious potential by his own forefinger, left forever numb from one bone-penetrating strike of an incisor.

Brodifacoum, registered in the United Kingdom in 1978 under the trade name Talon, would quickly replace warfarin as the leading weapon in the anti-rat arsenal. Back in the world of island conservation, the poison brought new hopes. Brodifacoum promised quicker death. It meant dead rats with fewer bags of heavy bait hefted into the wilderness. It raised the unthinkable possibility of eradication. Within a year of its arrival on the market, biologists were deploying brodifacoum on tiny islands off New Zealand's coast, testing the new poison in tandem with their more familiar snap traps and other poisons.

Among those most keenly following the developments was Rowley Taylor. He had once been among those accepting the party line, of the futility of fighting this formidable little animal on anything more than the tiniest offshore islands. But with brodifacoum now in the battery, the little victories beginning to amass, and a developing appreciation for the workings of rat society, the odds, to Taylor's mind, had fundamentally shifted.

The rat profile that Taylor had gleaned from labs like Kaukeinen's—and the endless flood of medical and behavioral research on the brown rat's domesticated model, the white lab rat—suggested a creature of complex social skills. The apparent chaos of wild-rat society, as inferred from the occasional glimpse of naked tails scattering before the flashlight beam, was, under closer scrutiny, a well-structured society of leaders and followers, rules and protocol.

Rat society was dominated by big males. The basic fact of their survival to adulthood, in the notoriously fast and ephemeral life of the rat, implied a degree of savvy, a calculated balance of daring and caution, a model to be emulated. The successful rat had evolved as nature's ultimate neophobe, a creature supremely and justifiably suspicious of novelty. Exploring new objects willy-nilly and mindlessly gobbling new foods were behaviors that characterized those seldom living to bear offspring. Mechanical traps, manufactured baits, poison pellets—all underwent careful inspection, most commonly led by the dominant males.

Once the new food or shelter had passed the sniff test of the colony's reigning kingpins—once they'd sated themselves and piled their larders to their greediest heights—the word went out. The message went forth on the scent of rat breath, passed like gossip in the myriad nose-to-nose meetings of the colony's cohorts. The message was “There's food back there, it's good, and the king's had his fill. Let's go.”

Following such protocol of rat society, Taylor sketched out his strategy. He would forgo the standard broadside in favor of the surgical attack. He would use just poison and the rats' own intelligence network to defeat them.

“Y
OU
'
RE
C
RAZY
, T
HOMAS
!”

Taylor now needed a target; his protégé Bruce Thomas knew just the place. Thomas had been itching for a shot at clearing Breaksea Island since his rude welcome there by rats a decade before. But both knew better than to aim their first stone at Goliath.

Thomas organized another research trip to Fiordland's Breaksea Sound, this time with Taylor to have a look at one of the candidates, a twenty-two-acre dome of forest called Hawea Island. It so happened that on that boat sailed their boss Richard Sadlier, director of ecology for the Department of Science and Industrial Research. It soon became clear that the would-be rat busters had more than rodents in the opposing camp.

As the three floated past Hawea, Thomas pointed and said to Sadlier, “There's rats on there, Richard, and that's where we should start.”

Sadlier scoffed. “Getting rats off a forested island like that? It's impossible. You couldn't do it. You couldn't get rats off a forested island like that. It's impossible.”

“Well, you know,” Thomas answered, “I think we could, Richard. But what do you think, Rowley?”

The laconic Taylor stood leaning on the rail, staring at the little island, then quietly declared, “Yeah, I think we could do it.”

Thomas then turned around, facing the looming profile of Breaksea Island, its monstrous heights wrapped in a band of mist, and dropped his bomb. “But
that's
the island I really want to do.”

Sadlier looked at Breaksea and all but jumped out of the boat. “Rats off that! Rats off that! You're crazy, Thomas! You're absolutely fucking crazy!”

Thomas again turned to his mentor. “What do you think, Rowley?”

Taylor panned the length of the island's forbidding ruggedness, contemplated for a bit, and nodded his head. “Well, it'll take a lot more time and money to set it up, but yes, I think we could do it.”

In March 1986, Taylor and Thomas and a handful of volunteers landed on Hawea, for what was to be a live rehearsal for their big show on Breaksea. They set about dissecting Hawea into a crosshatch of foot trails. Every forty meters of trail they stopped to place a bait station, each amounting to a fifteen-inch length of plastic drain pipe, anchored in place by hoops of fencing wire. They allowed three weeks for the most phobic of the rats to get comfortable with these foreign objects intruding on their territories, then laid the baits. On April 10, into each of the seventy-three plastic tunnels went two wax briquettes laced with brodifacoum at five parts per thousand. Seven days later not a rat could be seen on Hawea.

With Hawea's rats now history, Taylor and Thomas raised their sights to the ultimate target. Breaksea, to their minds, was a simple matter of scaling up their proven technique by the proper order of magnitude. But for those sitting in the administrator chairs, clearing Hawea's twenty-two acres was one thing; clearing Breaksea, at two hundred times the size, with forested mountains and cliffs, was another. Breaksea, the bureaucrats scoffed, would amount to nothing but a waste of personnel and money.

Their bosses would slash their budget, but by then Taylor and Thomas had all but set sail. They had already finagled a donation from a major manufacturer of brodifacoum. They had moles in the national park system organizing supplies, a hut, and helicopter time. They had already enlisted a league of volunteers from around the world, eager to be part of conservation history. With money and manpower already in place, the department heads found themselves politically hog-tied. They would concede to the minor mutiny, but not without one parting shot over the bow.

Taylor and Thomas, in earlier interrogations, had offhandedly estimated they could finish the job on Breaksea in about three weeks. Their rough estimate now became law: Taylor and Thomas and every last one of their troops were to evacuate Breaksea Island within twenty-one days of laying poison, rats gone or not.

As they had on Hawea, they would first quell the rats' anxieties and suspicions. Weeks before the first poison was laid, they laid their trails and plastic tunnels, freely inviting all comings and goings, laying a foundation of trust. By the end of April 1988, Breaksea had a bait station within sniffing distance of every rat on the island.

On May 25 the rat team assembled once again on Breaksea for final instructions. Taylor and Thomas had a team of six volunteer rat busters, a stockpile of 770 pounds of poison, and a helicopter pilot standing by for special duty. They gathered at command central—a rustic hut with a table, some chairs, and a map hanging from the wall. The map was pierced by 744 blue pushpins marking every bait station. On the table lay a box of red pushpins. As the rats began taking baits, the blue pushpins were to be replaced by red.

The next day the Breaksea troops headed out, shouldering sacks of bait. By the end of the day 744 stations, covering every rat territory on Breaksea plus two rocky spires offshore, contained two brodifacoum-laced briquettes of wax. There would be no place to run or swim for any rat of Breaksea.

Word spread quickly among the rat community: The strangers have come bearing food, and it is good. On the morning of day two the first checks of the stations would find baits missing. By day three every station was being pilfered. The map at headquarters flushed from blue pins to red. By day five the baits were disappearing as fast as the troops could lay them.

As the trap unfolded, Taylor took to hiding himself in the bushes and observing. He soon observed that the spying game worked both ways. One particular rat seemed oddly hesitant about entering the bait tunnel. Taylor sat and sat, waiting for the rat to make its move. Tiring of the game of patience Taylor looked into his lunch bag. As he looked up, the rat was exiting the tunnel with bait.

Taylor pretended to look again into his bag, this time spying out of the corner of his eye. As he reached in, the rat darted for the bait. Taylor now knew what it was to be under the scope, with a rat dissecting his every move.

The Breaksea eradication was going off like clockwork. The big males were laying claims to the stations, eating their fill, stocking their larders, chasing all comers, and eating again. The rats could hardly wait for their next visit from the men with satchels. Taylor would walk up to a tunnel, tap it as if leaving another offering, and pretend to leave. Almost before he was out of sight, the attending rat would be in the tunnel. Taylor watched one rat making off with no less than twenty-two baits.

Despite their eons of learned distrust, the rats had badly misjudged these strangers bearing gifts. As the poison settled into their livers, their lifeblood began to leak. As the leaders lay dying in their burrows, their unguarded territories came under siege by the next-boldest cohort. And on rolled the waves of death.

Back at headquarters, the battle was being played out in two dimensions on the wall. As the massacre progressed, the map changed color again. Red pins, signifying baits still being stolen, began to revert back to the quiet symbol of blue, now signifying death. By day ten half the stations on the island had been vacated. The masses were falling, the rat tide had begun to ebb.

As the deadline approached, the map tenders grew ever more busy pulling red pins, inserting the blue. On day twenty, amid a sea of blue, one lonely little red pin remained. And this, so far as Taylor and Thomas were concerned, was the last gasp of the living dead. Having already ingested a lethal dose several times over, the last rat of Breaksea was stockpiling its own grave.

Chapter 7

BAJA CATS

T
HE FOLLOWING DAY
, Rowley Taylor and Bruce Thomas were packing up and leaving Breaksea Island as planned. Three weeks to the day after laying the first bait, they had finished a campaign that the naysayers had bet would fail. As a parting act of insurance, they left at each station a double dose of poison and a single apple. They would return the next month and periodically thereafter to check for signs of Breaksea's rebirth, finding many; and to check the apples for gnawings, finding none. And indeed there would never be another rat found there.

Breaksea had reconfigured the horizons. It had demonstrated, on a beggar's budget and on hostile terrain, that a calculated dose of Kiwi audacity could beat the toughest, most intractable enemy of New Zealand's natural heritage. The gray curtain that had closed on the Wellington rat conference twelve years before, conceding a world forever compromised by invaders, had begun to lift.

With Breaksea in the bag, and their bait-station strategy now proven, Taylor and Thomas and their colleagues began eyeing bigger islands. And always with economy in mind. If an island was too big for the single storming of a little crew, they would whittle it down to size, parceling its overwhelming enormities into bite-size battlefields, deploying their bait stations in overlapping waves, one after the other, shore to shore—a rolling front, they would call it. By 1990 nearly forty of New Zealand's rat islands had been cleared by hand. That year the emboldened Kiwis added the helicopter to their arsenal, raining poison from the air and sending New Zealand's rat-free acreage on skyward trajectories.

Out of hard luck and desperation, the defenders of New Zealand's natives were pioneering a take-no-prisoners approach to biological conservation, saving island life by means of systematic eradication. And as it happened, would-be island saviors a world beyond were ripe to join the revolution.

C
LIPPERTON

In the spring of 1989 a biology student named Bernie Tershy landed a job observing seabirds from a government ship cruising off the west coast of Mexico. The project leader had arranged for a stop at a lonely little island far out at sea. The island, named Clipperton, came with masses of seabirds and an interesting history of their occupation.

Clipperton was a doughnut of nearly treeless land less than one square mile small and nearly eight hundred miles seaward from Acapulco. Sailors who began visiting the island in the 1700s were struck by this otherwise barren atoll so incongruously crawling with land crabs and stippled with nesting seabirds. The most conspicuous of the birds were two species of boobies—large, elegant high divers of the gannet family—nesting on Clipperton by the tens of thousands. The masked boobies of Clipperton constituted the species' largest colony anywhere.

Over the following two centuries the island underwent various exploitations and attempted occupations by several nationalities and one barnyard animal. American, Mexican, and French citizens came and went, but their pigs remained. Abandoned to their fates, the pigs made do by crunching their way through the scuttling fleets of land crabs and vacuuming up eggs and chicks from the seabird colonies. By the time biologists arrived in 1958 to survey the life of Clipperton, the crabs were all but gone, and the multitudes of boobies had been reduced to hundreds, the last of them huddled on a pig-free rock in the middle of the island.

It so happened that a man who had come to count their numbers—an American ornithologist named Ken Stager, from the Natural History Museum of Los Angeles County—had come toting a shotgun to bag a few bird specimens for his museum. Stager saw what the pigs were doing to the birds, took it upon himself to remedy the situation, and turned his bird-collecting tool on them. He circled the island, counting fifty-eight pigs along the way, and shot every last one of them dead.

By the time Tershy came to visit, the boobies were well on their way back, again amassing by the tens of thousands. (By 2001 surveyors would find Clipperton Island crawling under a living pavement of land crabs and inhabited by more than one hundred thousand boobies.) For him there was an epiphany in the little saga of Clipperton. Like so many of the conservation persuasion, Tershy in his fledging career had already tasted the creeping cynicism that invariably accompanied the losses. One could not live in coastal California, as he did, without witnessing the daily retreat of the wild places. Nor could one spend any appreciable time studying seabirds, the vocation Tershy was now courting, without repeatedly finding colonies decimated and littered with half-eaten carcasses.

But here, in this simple story of Clipperton, was an inspiring revision of the tired and tragic ending. A lone man with a gun had restored a hundred thousand seabirds—had revived a moribund island ecosystem. Formerly resigned to the narrative of doom, Tershy suddenly envisioned himself a savior of species.

Tershy's closest colleague and sounding board was a fellow seabird biologist working in La Paz, on the southern coast of the Baja peninsula. Don Croll had studied seabirds across both hemispheres, from penguins in the Antarctic to murres in the Arctic. He and Tershy had both witnessed the same recurring carnage, of seabirds congregating so faithfully and fatally in an island's broken seclusion. But on the flipside of that fatal flaw lay opportunity: Vanquish the threat, restore the masses. And the returns would multiply far beyond seabirds.

Acre for acre there was no real estate in the world of endangered life-forms more precious than that of the ocean's islands. Comprising 5 percent of Earth's landmass, islands had come to harbor one in every five species of bird, mammal, and reptile. They had also shouldered 63 percent of all their extinctions recorded during human history. Island species had come to populate nearly half of the list of the world's endangered. And most of those owed their endangerment to invaders.

For a pair of conservation biologists wanting quick and massive impact, there was no calling more obvious than making the islands safe from invaders. And for Croll and Tershy, there was no better place to start than Baja.

D
ESERT
I
SLANDS

Eastward between Croll's university on the Baja peninsula and the Mexican mainland lay the Sea of Cortez. Thirty miles west lay the Pacific Ocean. Within these coastal waters of Baja arose some 250 desert islands, generally distinguished by a scarcity of human settlements and a striking profundity of wildlife and wilderness.

These were islands stark in appearance and astonishingly rich in their life-forms. On the sun-beaten beaches and sea cliffs, great colonies of seabirds would gather to nest. The isolation that drew the flocks had also modeled the islands' resident individuals into peculiar forms—of sparrows and rodents, lizards and snakes, changing form from one island to the next. For modern-day wannabe Darwins, this was the magic kingdom.

For the biologist concerned with saving the creations, however, the Mexican islands more resembled an inner-city emergency room at midnight. The islands came plagued by the usual cast of suspects from the mainland, the rogues' gallery of burros, goats, rabbits, rats, and cats—grazers, browsers, meat hunters, and egg thieves, nibbling and gnawing and mauling their way through the evolutionary oddities and seabird masses. The list of casualties ran long. Recently gone were the Todos Santos rufous-crowned sparrow and the Todos Santos wood rat. Gone too were the San Roque white-footed mouse, the McGregor house finch, and the Guadalupe storm petrel. Nineteen species of native animals had been extinguished from the Mexican islands since the time of human settlement, eighteen of them with help from the modern menagerie of invaders.

Croll and Tershy, as would-be island conservationists, found they weren't alone. Beyond Ken Stager's impromptu pig eradication on Clipperton, there was the ongoing campaign of the U.S. Fish and Wildlife Service, already years into liberating Aleutian seabirds from imported foxes. A team of independent biologists were even then readying themselves to eradicate bird-killing cats from Wake Atoll, in the western Pacific. And leading the way from Down Under were those pioneering Kiwis, escalating the offensive against the raiders of their island nation. Croll and Tershy believed they could do likewise for Baja.

Though the two soon migrated to faculty positions at the University of California, Santa Cruz, their focus remained fixed on saving the Mexican islands. They teamed with José Ángel Sánchez-Pacheco, a marine biologist from Baja with a kindred passion for island life and a behind-the-scenes talent for navigating the Mexican bureaucracy. Their plan took shape. They would seek their funders in the richer pockets north of the border, rally their Mexican colleagues south of it, and together, as an international team, save this beleaguered part of their world under a bilingual banner of island conservation.

If they could somehow deal with the cats. The two most immediately troublesome invaders blocking their way were Baja's rats and cats. With the blood-thinning brodifacoum on the shelves and the New Zealanders' bait-station protocol now on the books, the conservationists already had the means and the model for confronting the rats. The cats, on the other hand, had yet to reveal any such silver bullet weakness. And as of 1994 there were twenty-six islands in northwest Mexico harboring menacing populations of them. The trio of conservation biologists found themselves woefully out of their league as cat hunters. Hence their first and most important hunt sent them in search of one.

T
HE
C
ATMAN

Bill Wood was a retired trapper from the desert flanks of California's southern Sierra Nevada. Wood's specialty was the bobcat, a brawnier, stub-tailed cousin to the domestic cat. Over the years, Wood had honed his craft, earning a comfortable living trapping bobcats and selling their pelts. He had gained a reputation in Southwestern trapping circles as the king of bobcats. To some he had even come to embody his quarry, wiry and alert, right down to his probing feline eyebrows.

The recipe to Wood's success amounted to several decades of trial and error, and a dash of the intangible better described as art. Wood shunned gimmicks. His trap of choice was a standard Number 3 Victor leghold trap, featuring a pair of spring-loaded steel jaws triggered to bite upon the weighting of a cat's foot. Beyond that, he parted company with the crowd. Where others baited their traps with veritable billboards of elaborate lures and witches' brews of foul-smelling scents, Wood placed his faith in the subtle skill of placement. He had learned to read the land for its natural corridors and travel ways, the most likely paths by which the cat would cover its territory. If need be, he would delicately arrange surrounding rocks and bushes into chutes to guide the unsuspecting forefoot exactly to the center of his trap. Precision was key. An inch or two to either side risked a misfiring or an escape. Wood didn't lose many cats to miscalculation.

Or to the competition. Wood once found himself sharing a trapping territory with a man who had all but mined the mountain with traps. Wood laid out his three traps to the other man's seventy-five. And every day on his rounds he would stop by the enemy's camp for coffee, to listen humbly to yet another sad tale of rotten luck. The man eventually packed his gear and left, empty-handed and grumbling something about a scarcity of bobcats, unaware of the daily stash of pelts piling up in the back of Wood's truck.

Wood went to great lengths to guard his secrets. If he erred so much as to make a track in the sand, he would brush it out, to keep both bobcats and snooping trappers clueless of his presence. He had no intention of letting freeloading neophytes go “to school on him,” stealing with a glance the techniques he'd honed over years of dirt time. One trapper offered Wood a thousand dollars just to let him tag along. “Didn't seem like a good deal to me,” Wood would later say. “I was making that much in a day.”

Croll and Tershy caught wind of Wood's ways with wild cats and called for his help. He was by then enjoying the retired life with his wife, Darlene, remodeling one of his several vacation homes, trapping as it pleased him, and indulging an addiction to fishing. But he was barely sixty years old and still harboring the adventurer's itch. Now here was this stranger on the phone, offering to pay him for a stint on a sunny desert island in Mexico. And oh, by the way, the fishing was great. Wood, who spoke no Spanish and knew next to nothing of trapping feral cats, said what the hell, packed his gear, and headed south.

Before sailing off on his Baja assignment, Wood, the hired catman, was briefed on the adversary. The feral cat was the vagabond version of the world's most popular pet. Its alter ego, the domestic cat, had descended from
Felis silvestris
, the wildcat, a lithe little hunter originating in the Near East. It was there, some ten thousand years before, in the rich Mesopotamian river valleys of Iraq and Israel, that the first cultivated crops of wheat and barley began to replace the wild produce of hunting and gathering as the human's basic sustenance. The prevailing speculations picture a pioneering wild cat wandering into one of the rudimentary villages of the dawning age of agriculture, drawn by the rats and mice foraging in the first farmer's new grain bins. The farmer, quickly tiring of the pilfering rodents, grew to appreciate these wild little predators lurking about. And when the resident she-cat eventually had kittens, the kittens eventually became pets. It was a bargain for both. The cat got her mouse, the farmer got her grain, and both even came to enjoy each other's company on the side. In the shrewdest of evolutionary plays, the wild cat domesticated itself unto the wealthiest provider in the animal kingdom.

Over the next nine thousand years, progeny from that domestic cat—and perhaps from a handful of others hitting independently upon the same winning ticket—would come to number more than half a billion. More so than the appeasement-driven dog, the domestic cat retained its wild independence, tiptoeing a fine line between purring lap cat and hissing spitfire, a certain wildness that would serve it well whenever the interspecies marriage went sour. Cats could be abandoned just about anywhere and make do. They sailed the Atlantic with Vikings, sailed the Pacific with Captain Cook, explored the subantarctic with sealers. They were commonly presented as goodwill gifts to native islanders. Other times they jumped ship and made themselves at home. The cat rode the coattails of humans to the ends of the earth, and many islands in between.