Where the Wild Things Were

by William Stolzenburg

  It soon became apparent that this plague of little predators had long legs. By the mid-1980s, at about the time David Wilcove was publishing his ominous observations from the Eastern forests, a fellow conservation biologist on the other side of the continent—in an arid Southern California landscape poles asunder from the leafy green woods of the East—was inadvertently heading toward a similar discovery.

  Michael Soulé had grown up in the coastal hill country of San Diego and had become a naturalist poking about the dry mesas and sharp canyons scruffily cloaked in sage and oak scrub—“those wonderful strips of native vegetation running through the city,” as he called them. After stints as a biologist in Africa, a tenured professor at the University of California at San Diego, and a meditative life at a Los Angeles Zen center, Soulé returned to the San Diego chaparral and his beloved “home in the boonies,” just in time to find the real estate developers planning a new city that would all but swallow his sanctuary.

  “I realized it was unstoppable,” Soulé said, “but I thought maybe they could do it in a way that could protect some of the conservation values and wildlife in the area. So I approached the developers and said, ‘Look, there’s a way to do this that probably won’t cost you anything but will allow some of the wildlife to exist, just by making sure some of the connections in the canyons are maintained.’” He told them about island biogeography, about the inherent ecological dangers of isolation. The developers informed Soulé that island biogeography did not apply to southern California.

  “They blew me off,” said Soulé. “And I got mad. I said, screw you. I’ll start a research project.”

  Soulé mobilized a team of students and faculty from the University of California at San Diego. They set out to document the biological fallout as the chaparral was carved to little bits. Soulé chose for his barometer a special group of birds.

  The canyons harbored a suite of birds tightly tethered to the chaparral. The group was a varied lot, including the California thrasher, the California quail, two species of wren, a colorful sparrow called the spotted towhee, the greater roadrunner, and two active little insect gleaners, the wrentit and black-tailed gnatcatcher. The chaparral birds rarely flew far, and seldom foraged or bred elsewhere but in the native shrubbery. Wings notwithstanding, they were essentially stranded in their little pockets of scrub. As the steep-walled canyons lost ground to the earthmovers and home builders, the obligate birds of the chaparral were squeezed ever tighter amid their shrinking archipelago of habitat. It had apparantly become a question of island biogeography as to how long the birds would survive in their little lots—how long before a brushfire incinerated their little sanctuaries, how long before inbreeding sent the population into a death spiral of genetic decay.

  One of his first days of fieldwork, Soulé and team came to the fragment on Point Loma. It was a tiny patch, no more than two or three acres. Soulé had often explored there as a kid. He and his coworkers sat on the edge, listening and watching for the chaparral birds they were sure must be there. There was nothing. “And it just hit us,” Soulé recalled. “Wow. It’s real. We didn’t know we’d see such profound effects.”

  As Soulé and company got down to business, they took stock of thirty-seven chaparral fragments scattered throughout the San Diego suburbs, the smallest of them amounting to less than a half acre, the largest about a hundred. For some, it had been only two years since the houses and fences and highways had sealed them off; for others, it was going on a century. Soulé fully expected to find the birds closely tracking the tenets of island biogeography, their numbers declining over time, most drastically as the size of the islands got smaller and the spaces between them larger.

  At the last minute, Soulé decided to add one more variable to his analysis. Anticipating his critics, he conceded to measure the impact of predation. “If I didn’t look at predation,” said Soulé, “the people would say, ‘Well, how do you know foxes and cats and coyotes aren’t killing off the songbirds?’ So we had to look at least at the presences and absences of predators.”

  After two years of surveys, the results were tallied. Predictably enough, the patches were dropping species of chaparral birds over time, in line with the diminishing area of chaparral. But as Soulé ran down the analyses, an unexpected third factor leaped out of the data, striking him squarely between the eyes. The diversity of chaparral birds was higher in those patches inhabited by coyotes. And Soulé instantly understood why.

  He recalled those unforgettable moments at his little house on the chaparral, when the cat door would suddenly explode. “Bang-bang-bang, as the cat came flying through, racing like he was being chased by the devil,” said Soulé. “And he was. He was being chased by a coyote. My, we lost a lot of cats.” The wisest cat Soulé recalls ever owning had spent most of its time on the roof.

  The significance, as Soulé and team would later formally summarize for print, “suggests to us that coyotes are helping to control the smaller predators (including cats) in the canyons, possibly contributing to the maintenance of the native, chaparral avifauna.”

  The phenomenon behind Soulé’s conclusion was the same phenomenon that John Terborgh had postulated for the demise of the birds by coatis on Barro Colorado Island, the same that his student David Wilcove had uncovered in the urbanized Maryland forests. By all appearances, in places where the dominant predators disappeared, a guild of smaller, mid-size predators (or mesopredators, as Soulé came to call them) took charge and rioted, multiplying by as much as tenfold. Ecologically speaking, when the top dog was away, the underdogs—and undercats—would play. “The phenomenon appears to be quite general,” wrote Soulé and colleagues. “We refer to it as ‘mesopredator release.’”

  The mesopredators had indeed been released, as a quick scan of the continent revealed. In the prairie pothole region of the Dakotas—famed as the duck factory of North America—red foxes had by the 1980s taken to cleaning out duck nests. Throughout the shrinking forests of Illinois, an entire suite of ground-nesting songbird species was failing at dramatic rates, in suspicious concordance with a threefold surge in the raccoon population. Up and down the eastern seaboard, on the beaches and in the maritime forests of the Atlantic, shorebirds were being chased off by roaming dogs and house cats and urban gulls; colonies of thousands of terns and skimmers and herons and egrets were deserting en masse, put to flight by marauding raccoons and foxes.

  Across the Atlantic emerged more outbreaks of second-string predators, none more frightful than the plague of baboons sweeping the poacherravaged reaches of sub-Saharan Africa. From the Ivory Coast to Kenya, in the expanding vacuum of missing lions and leopards, monstrous gangs of baboons had begun terrorizing the countryside. Free to wander when and where they pleased, the emboldened apes were to become Africa’s chief crop raiders and ubiquitous thugs, mugging women and children for their food, breaking and entering houses, and slaughtering livestock and wildlife in crushing quantities. In hard-hit pockets of Uganda, kids were staying home from school to help guard the family’s fields and flocks. The marauding apes, indulging their growing appetite for meat, began gang-tackling wild antelope, tearing them limb from limb. In the aftermath of the rioting baboons, scientists would find fellow primate societies annihilated, whole forests of bird nests plundered. Baboons were evicting hyenas from their kills. Having dethroned the lion, Africa had crowned a tyrannical new king of beasts.

  Soulé’s mesopredator release hypothesis suggested a likely explanation to many wildlife declines and disappearances sweeping across the land. For little populations already squeezed to the edge, the modern pestilence of subordinate predators was amounting to the unbearably heavy load.

  But for Soulé, mesopredator release presented an equally intriguing flip side. Could mesopredator restraint actually rescue such species on the brink? Could it be, for example, that such a predator as the coyote, the most vilified creature in the history of America, was standing between chaparral birds and their extinction by mesopredato
rs?

  It wasn’t long before tests of Soulé’s suspicions began to gain scientific credence from sites far beyond the California canyons. In the prairie potholes of the Dakotas, where the red foxes had been emptying duck nests with tailspinning rapidity, an unforeseen return of the coyote was turning things around. After decades of fanatical warfare against the coyote, in which half a million of the song dogs were being shot, gassed, poisoned, trapped, and strangled year after year, the 1970s came with rumblings of a cease-fire. The shifting cultural climate brought lower fur prices and fewer trappers; societal and scientific outcry led to President Richard M. Nixon’s 1972 ban on public-land poisonings. In South Dakota, aerial gunners were temporarily grounded.

  The coyote, given its momentary stay of execution, wasted no time looking back. In the Dakotas their numbers surged. And with the return of the coyote, the reign of the red fox ended. The coyote, less a hunter of eggs and more a hunter of mice and rabbits—not to mention trespassing foxes—actually made life safer for the ducks. Where the coyotes had come to rule, the average nest success of the Dakota ducks jumped by fifteen percentage points, enough to lift the nation’s duck factory out of the red. The authors of one key study even went so far as to prescribe coyotes as a means of duck production—an eye-raising suggestion from a profession in which many had invested careers in the coyote’s eradication.

  Meanwhile, in an expanse of short-grass prairie in western Texas, a wildlife biologist named Scott Henke was himself questioning the conventional wisdom of killing off coyotes. Aerial gunners had swooped down and removed half the coyotes over thirty-nine square miles of Henke’s study site. Within nine months of the shooting, the prairie was jumping with kangaroo rats, to the demise of its eleven fellow rodent species. Black-tailed jackrabbits, on the other hand, tripled in number. And to no surprise, the skunks, foxes, badgers, and bobcats of the mesopredator clan also gained at the coyote’s expense. Henke’s postmortem inventory left one to wonder if the coyote gunners hadn’t shot themselves in the foot. How many pounds of the rancher’s cattle forage had the booming jackrabbits nibbled away? How many eggs of the quail hunters’ quarry had the surging mesopredators gobbled in the coyote’s absence? These were the fuller range of questions and consequences Henke implored others to ponder before shooting: “Biologists need to remember that indirect effects are the rule rather than the exception in most ecosystems,” he wrote.

  Nearly a decade after his serendipitous discovery in the San Diego canyons, Soulé returned to his chaparral birds for a reexamination of the phenomenon he had made famous. This time, with a graduate student named Kevin Crooks, Soulé set his antennae more pointedly at the carnivore community. Crooks set out track stations and trip-set cameras, gathering footprints and incriminating photos. He and his assistants gathered scat as well, sifting through postdigested items on the carnivores’ daily menu. And with an extra dose of suspicion, they ordered round-the-clock surveillance on the canyons’ cats.

  Crooks went around to the canyon’s bordering homes, knocking on doors.

  “We’re doing research down in the canyon. Do you have an outdoor cat?” he would say.

  More often than not, the answer was yes.

  “Do you let it run loose?”

  Lots of nods.

  “Would you mind if I put a radio collar on it?”

  Domestic Violence

  There was by this time ample reason for suspecting the household carnivore. Since its domestication four thousand years earlier by the Egyptians, Felis catus had become the world’s secondmost fearsome predator (behind only the rat, which, to be taxonomically fair, is a generic name ascribed to at least three species). The domestic cat, from the backyard venturer to the abandoned pet gone feral, had over the past five hundred years spanned the continents and major islands of the world. Turned loose upon the global fauna of native rodents, rabbits, birds, snakes, and lizards, it had chalked up a conservative estimate of thirty-three extinctions and uncounted decimations.

  When curious scientists first started taking serious note of the predatory habits of the presumably harmless house cat, the enormity of the massacres stunned them. In the British village of Bedfordshire, biologists Peter Churcher and John Lawton enlisted an entire community of cat owners as field assistants in what would become a landmark study of domestic predation. They went door-to-door with their feline census, tallying seventy-eight cats variably attached to 173 houses in the community. Churcher and Lawton instructed their amateur corps of wildlife scientists to bag the contents of any prey their cats brought home. By years’ end, the villagers of Bedfordshire had proudly presented the carcasses and body parts of 1,100 little animals. Mammals were especially popular, the bags filling with mice, voles, and shrews, here the occasional rabbit, there a weasel. One cat specialized in slaying bats. An impressive sampling of birds rounded out the cats’ take. House sparrows, thrushes, robins, and blackbirds were all brought home for the master of the house. Some of the more industrious cats were bagging a hundred bodies a year, and it was not hard to imagine at least that many more victims never quite made it home.

  When Churcher and Lawton started extrapolating Bedfordshire’s results across Britain, the quaint little survey grew morbidly huge. The cats’ annual countrywide take came to seventy million mammals and birds. The ecological gravity of those numbers was lost on many of the killers’ owners. When the scientists published their results, other cat owners proudly wrote in—some apparently with Guinness Book ambitions—bragging about yearly scores of up to four hundred animals.

  Bedfordshire became a microcosm not only of Britain but of the world. Fed and sheltered by society, unhindered by disease or starvation, their killing dampened neither by satiation nor scarcity of prey—immune to the hardships faced by its competitors attempting an honest living in the wild—the cat as recreational hunter had become a formidable blight on both predator and prey. In the United States alone, there lived anywhere from sixty million to one hundred million cats, most of them household pets, with uncounted millions lurking in semiwild populations. In rural Wisconsin, free-ranging cats had exceeded one hundred per square mile, outnumbering by several times all the native foxes, raccoons, and skunks combined. There were cats in America that could put the Bedfordshire hunters to shame, some credited with one thousand kills in a year. When all were accounted for, U.S. house cats were each year dispatching upward of a billion mice, voles, and baby rabbits, plus hundreds of millions of birds.

  And not all of those populating the hit lists were garden-variety creatures. On the dunes and sands of coastal Florida, the cats were plundering imperiled populations of beach mice and piping plovers. On Key Largo, a colony of five hundred feral cats had taken up residence within stalking range of an endangered species of wood rat.

  On naïve island faunas around the world, the cats’ consequences magnified. The house cat ambushed its way through rare rodents in the Caribbean and Baja and rare lizards of New Zealand. Before dispatching the last of the Guadalupe storm petrel, a small seabird nesting in burrows, cats were killing nearly half a million petrels per year. Before conservationists stepped in and killed the cats on Natividad Island off the coast of Mexico, the cats had been cropping a nesting colony of black-vented shearwaters by a thousand birds a month.

  Now, the cats were toying with Michael Soulé’s beloved islands of chaparral. In an average-size fragment of undeveloped canyon, sport-hunting house cats were retrieving close to two thousand mice, birds, and lizards per year, not to mention how many more they ate on the spot or left to the ants. With that kind of take, it no longer seemed so mysterious that over the past century, the chaparral fragments had suffered at least seventy-five extinctions of their obligate birds. Accounting only for the house cat’s carnage, it was easy to figure why the birds of the chaparral were winking out like a cheap string of Christmas lights.

  But here, at least in a few of the bigger tracts of canyons, something was standing in their way. What in Soulé’s 1988 study
had been a suggestive clue to the beneficent power of the coyote, in his new study soon hardened with organic data. One in every five coyote scats contained cat remains. One in every four feline radio collars ended up leading a researcher to a remnant of somebody’s pet, typically half-buried beneath a shrub. The mere suggestion of coyotes on the prowl had nearly half the canyons’ cat owners keeping their loved ones inside. And that, to many little native residents of the chaparral, amounted to salvation. Where the coyotes roamed, the cats ran scared, and the chaparral birds sang.

  It was a conclusion with awkward implications for so many. The chaparral fauna was being drained into the maw of society’s most popular predator, only to be spared by the graces of its most persecuted. Canis latrans, the coyote—scourge of delinquent cats, guardian of imperiled birds, benevolent alpha predator of the San Diego chaparral.

  It was solid science with quirky mainstream appeal, appearing in the science journal Nature as well as the New York Times. And yet it was a story about to be eclipsed by orders of magnitude, by another of uncanny similarities and striking contrast. The new story involved the coyote’s big brother, the wolf, bringing protection to a place as wild as the San Diego suburbs were domestic—a place called Yellowstone.

  EIGHT

  Valley of Fear

  IN ITS MEANDERING PATH across the northern tier of Yellowstone National Park, the Lamar River emerges from a mountain canyon upon a lofty valley of grass and sage. There it flows through what many eyes perceive as the premier wildlife panorama of the Lower 48. The Lamar Valley is the place to find the grizzly pawing through the summer grasses, to hear the bison bulls bashing heads in the September rut, to scan the sere valley plains and hill-sides flashing yellow with the rumps of grazing elk. The coyote pouncing for voles in the grass, the pronghorn antelope galloping over the sage flats—the reasons the asphalt two-lane that snakes across the Lamar terrace so often crawls with sightseers—had little to do with Robert Beschta’s astonishment on his first visit in the spring of 1996. A hydrologist from Oregon State University at Corvallis, Beschta had walked straight from the tour road to the banks of the Lamar, eyes fixed on the river itself. Or rather, from Beschta’s frame of reference, what was left of it.