CHAPTER NINE
To cherish what remains of the Earth and to foster its renewal is our only legitimate hope for survival.
—Wendell Berry
Memories of the spring bloom of Washington, DC’s beloved cherry trees were still fresh in the minds of members of the U.S. House of Representatives as Hugh Hammond Bennett stood before them on a sunny Friday in May 1934. Bennett, director of the recently formed Soil Erosion Service, an agency of the U.S. Department of the Interior, knew something that the congressmen did not: that a large dust cloud was rapidly moving east from the Great Plains and would soon deposit millions of tons of dust on the nation’s capital, New York City, Boston, and even on the decks of ships hundreds of miles off the eastern seaboard. A story in the New York Times reported that airborne topsoil had “lodged itself in the eyes and throats of weeping and coughing New Yorkers.”1 Bennett had been conducting soil studies for some thirty years and had begun warning of the potentially catastrophic effects of soil erosion in the 1920s—most pointedly in a U.S. Department of Agriculture study entitled Soil Erosion: A National Menace. Grassland was being plowed under and grazed at unprecedented and unsustainable rates, leaving no roots to hold the soil together. With the drought cycle that began in 1931, crops that had been holding the soil intact died, and the topsoil began to literally blow away. Dust storms had been blowing across the plains with increasing frequency, blotting out the sun and enveloping whole structures, yet the gravity of the situation had not struck home with lawmakers or the East Coast establishment until now. As the dark cloud of soil swirled around the Washington Monument, the Lincoln Memorial, and Capitol Hill itself, Bennett is said to have announced to the assembled representatives, “This, gentleman, is what I have been talking about.”2
Washington got the message and by 1935 had enacted the Soil Conservation Act, mandating crop rotation, new plowing methods, and aggressive grass seeding. In short order, dust storms were reduced by more than half. But these improvements came a little late for the more than 3 million people who had been displaced from Oklahoma, Arkansas, Missouri, Iowa, Nebraska, Kansas, Texas, Colorado, and New Mexico. Acting in ignorance of the consequences of their farming techniques—and in part from blind self-interest (hoping to grow and sell as much wheat as possible)—these Dustbowl refugees were compelled to take to the road in search of a new life. Many experienced the wrenching poverty and humiliation so well captured in the photography of Dorothea Lange and the prose of John Steinbeck’s Grapes of Wrath.
It is a strange quirk of human nature that we are often unable to respond to problems until they manifest themselves as grand disasters. Whether they are impeded by an unrelenting focus on the short-term, a powerful willingness to filter out bad news, or a tendency toward inertia, many leaders would rather postpone action—take a wait-and-see attitude—than proactively work toward a solution. This tendency appears especially intractable when it comes to environmental or conservation-related issues. For so many generations the American landscape offered seemingly endless bounty—so many bison, so many Passenger Pigeons, so many salmon. Perhaps as a people we have been lulled into thinking that in a land of such plentitude, biological resources are truly infinite and will take care of themselves—until suddenly we are trying to save the last remnant populations or they are already gone.
There is little question that free-ranging cats—both the unowned and the owned pets allowed to roam freely outside—pose a pending ecological and public-health disaster. As of this point, it is equally evident that little if any action is being taken to address this problem; indeed, very few people even recognize it as a problem. This raises the question, what sort of emergency—or tragedy—will it take to spur us to action? Will it be the extinction of another species, thanks, in part, to cat predation? Must the Piping Plover, the Hawaiian Petrel, or the Lower Keys Rabbit (or any of a number of other birds, mammals, and other creatures) be lost from the earth forever before we can act? Or will it be an outbreak of disease that has spread from cats to humans—deaths due to rabies or plague, or a spike in cases of schizophrenia and incidents of suicide brought on by the dissemination of Toxoplasma gondii?
The consequences of an upsurge in diseases linked to toxoplasmosis are obvious and severe. The fallout we experience as a culture when the populations of a species decline or a species leaves the planet forever is also severe, yet so much harder for many to comprehend. Why does it matter that a small bird or a rodent whose primary habitat is thousands of miles from our home disappears? Nature writer Ted Williams, ruminating on the future of the Florida Grasshopper Sparrow (Ammodramus savannarum floridanus), a critically endangered subspecies declining primarily due to habitat loss, speaks to one reason why a species should persevere:
Maybe the only explanation for people who have to ask why the Florida grasshopper sparrow matters is this: It matters not because it is a source of enrichment for human lives (although it is), not because it is a source of medicine or agent of pest control (it is probably neither), not because it is an “indicator species” that tells us we haven’t completely wrecked our habitat, not because it is anything, only because it is.3
The novelist and environmentalist Edward Abbey put it slightly differently:
I am weary of the old and tiresome and banal question “Why save the wilderness?” The important and difficult question is “How? How save the wilderness?”4
Ecologists will often couch the importance of each species within the notion of the tapestry of life. The understanding here is that every organism has an ecological function that serves the larger ecosystem. Each time a species declines a thread of the tapestry is frayed. Each time a species goes extinct a thread is lost. The more threads that are compromised or lost, the more compromised the tapestry, until finally it unravels. Some of the ecological services provided by species are obvious: honeybees pollinate plants and trees so they can reproduce; birds reduce plant-eating insects so trees can grow; wolves cull Elk that are sick or old so the herd does not exceed the carrying capacity of the land. Others are less obvious. The Gray Wolf (Canis lupus), for example, set in motion a cycle of recovery when it was reintroduced into its former territory in the Greater Yellowstone Ecosystem in 1995. After the last wolf in Yellowstone was killed in the 1930s, the population of the Elk (Cervus elaphus) slowly ballooned. Additionally, the Elk became less inclined to move about or disperse to avoid predation, and instead focused their browsing—especially in the wintertime—around rivers, where they fed on young willows. The absence of willows suppressed populations of the American Beaver (Castor canadensis), which relies on willows to survive. With the return of the wolves Elk stayed on the move and broke into smaller groups, no longer concentrating around the rivers and the willows. The willows recovered, resulting in a return of beavers. Back in healthy numbers, the beavers began building new dams. The dams impacted stream hydrology, helping regulate flow, and created a better rearing habitat—shaded and cooled by the reinvigorated willows—for young Cutthroat Trout (Oncorhynchus clarki).
Most ecologists will readily admit that we do not understand the role that each organism plays in the tapestry of life, nor do we exactly comprehend how all the strands fit together. At the same time, they will also express great concern about the future that awaits us should this at once powerful and fragile web begin to unravel.
Birds—and the larger ecosystems they represent—face threats from many directions. Some challenges, like climate change and the loss of habitat brought on by overdevelopment, are so monolithic as to seem insurmountable. One might be willing to leave the car at home and bike to the store to buy a head of organic lettuce, but does this small nod to reducing greenhouse gases make a difference—especially when the lettuce has been trucked in from a farm 200 miles away? The challenge free-ranging cats pose to the well-being of our environment is not on par with climate change. But it is one that each of us can do something about, and it is a problem that can be reversed in a relatively short time. The good news is that nature is resilient once given a chance.
Humans, as a species, also face many threats in the form of virulent disease. Though malaria (caused by a parasite transmitted by mosquitoes) has largely been eradicated in the United States, the disease still claims hundreds of thousands of lives each year, especially in sub-Saharan Africa (627,000 in 2012). We understand the cause of malaria, and we can inoculate people to minimize the probability of disease. If a person becomes infected and is diagnosed early enough, the disease can usually be successfully treated. Emergent and deadly diseases (like Ebola and Zika virus) appear every few years, straining available resources, as epidemiologists, doctors, and public-health officials scramble to understand the disease, to treat those afflicted, and to prevent its spread to the larger population. Some of the various pathogens that free-ranging cats carry and can spread to humans—such as rabies and plague—will likely not reach epidemic proportions. Infection with Toxoplasma gondii, however, is already at epidemic proportions and presents us with a different situation entirely. We understand the root cause of this malady, and we have it in our power to avert a looming public-health crisis.
In the previous chapter, we explored some practical solutions for taking control of free-ranging cats. Before we can act upon these recommendations, however, there are two obstacles of a more philosophical nature that stand in our way. The first is the average individual’s lack of a grasp on the enormity of the problem. Ecologists spend their time considering and studying concepts of scale—quantifying local data points, say, from a neighborhood, and scaling them up to a city, then regional, then continental level. This issue just is not on the radar of most people. As Jennifer McDonald and her colleagues point out in their study about cat owners’ attitudes toward their pets’ predation habits (discussed in chapter 8), cat owners need to apprehend how individual predation rates scale up with increased cat densities if they are ever to understand the impacts of cats on wildlife. Without more information and knowledge, it will be difficult for the average person to think about how the handful (or bucketful) of birds killed by his or her cat or those stray cats in the woods behind the local convenience store are emblematic of a widespread and grave problem.
This inability to contextualize scale speaks to a larger challenge—the unwillingness or inability of many people to acknowledge the validity of scientific research, especially if it contradicts their own belief system. Washington Post reporter Chris Mooney has studied the topic of science denial extensively. Mooney notes that it is human nature to have blinders on in certain situations and that our prior beliefs have the power to skew how we process new information—they even guide the sort of memories and associations that we summon in our conscious mind. This phenomenon is called confirmation bias. Mooney cites climate-change skepticism as an example of science denial and also the furor over childhood vaccines, which many believe (falsely) to cause autism. In the case of the latter, deniers have created their own media (e.g., the website Age of Autism), which in turn are cited as “authorities” and pounce upon any new reports casting doubt on their views with vitriolic critiques and refutations—much in the manner that many outdoor-cat advocacy groups attack any new studies suggesting that free-ranging cats pose a problem.
The second obstacle that needs to be overcome is the unwillingness of some people to acknowledge that euthanasia needs to be part of a successful long-term solution. Michael Soule, a champion of preserving biodiversity who is considered one of the founders of conservation biology sees this unbending adherence to a no-kill ethic as a case of misplaced compassion (fig. 9.1). “There are people in the conservation and animal welfare movement who oppose killing in general,” he said recently. “But that’s not always the most compassionate stance to take. It would be misplaced compassion not to kill in some instances, as it’s the most merciful thing to do in that place and time. But you never forget that killing. It’s part of the paradox of compassion. Sometimes you suffer when you are being compassionate.”5
Many outside of the conservation/ecology community will continue to dismiss the idea that free-ranging cats pose any ecological or public-health danger, no matter what evidence is presented. Some of those willing to acknowledge that cats might have an impact on wildlife will hasten to add that the problem is limited to islands. There is no question that free-ranging cats have had (and will continue to have) a disproportionate impact on islands. As previously discussed, many of the confirmed thirty-three cat-driven species extinctions have transpired there. Indeed, many of the endemic birds of the Hawaiian Islands currently reside on the endangered species list, their future hanging in the balance, thanks in part to free-ranging cat predation and disease transmission. But as Stanley Temple’s 1989 research showed—and many subsequent studies have confirmed—the impact of free-ranging cats is being felt on mainlands as well, more acutely in some places than others. Temple’s research showed that the “islands” of intact grassland in Wisconsin that were maintained as natural habitat between row crops became a focus for cat predation, though they had been established in the first place as a haven for wildlife. Development in urban and suburban areas has resulted in fragmented natural habitats that also resemble islands, albeit islands with a concentration of subsidized predators (e.g., cats who are fed by humans) and an absence of larger predators, like Coyotes. As was discussed earlier, the impact on wildlife in such “islands” is catastrophic. Clearly, cats have impacts on populations on mainland areas. Will free-ranging cat populations take hold on the Great Plains, in the Sonoran Desert, in the Rockies or Columbia Basin, menacing bird and small mammal populations? It’s quite possible. Free-ranging cats—potentially as many as 150 million when owned cats that are allowed outside are included—will likely continue expanding in temperate areas where well-meaning but misguided individuals take pity on them and provide food or in remote areas where there’s enough wildlife to sustain them. These cats will continue decimating native wildlife populations and spreading pathogens and the diseases they cause at an accelerated rate as their numbers expand. That is, unless we can garner the political and moral will to begin to take control.
Free-ranging cats are not harbingers of the apocalypse. They will not radically change life as most of us know it in the United States, as climate change and habitat destruction do. But if present trends continue, their growing presence will result in an uptick—perhaps considerable—of zoonotic diseases. And we will continue to see declines in the populations of native birds and other wildlife in regions where free-ranging cats are present. More and more Americans will awake to muted birdsong, if any at all; more and more bird feeders will go unvisited. We will be left with a world that is recognizable but a bit more monochromatic, a bit less diverse.
The state of Florida provides a hint of what may await us, at least from an ecological perspective. Historically, Florida has been one of the most species-rich states in America. In the last century, much of the state’s coastal prairie, pine flatwoods, and hardwood hammocks have been cleared for development. Landscapes that have not been cleared—especially in the Everglades—have been impacted by man-made hydrological regimes. Remaining swaths of undeveloped, intact habitat have been bifurcated by roads, creating fragmented “islands” that limit mobility and otherwise compromise ecological functions. These factors—abetted, in some regions, by free-ranging cats—have resulted in Florida having the nation’s third-highest number of endangered and threatened species, behind only Hawaii and California: fifty-one federally designated endangered species (including eight birds) and thirty federally designated threatened species (including five birds). Florida is also especially noteworthy for the number of invasive species that have taken hold—more than 500 exotic species of fish and other life-forms have been recorded in the Sunshine State. Some of the better known invasives—the Burmese Python and monitor lizards, for example—have become established mostly because irresponsible pet owners released them into the Everglades (and other wetlands) once they became too large and unruly to handle. The subtropical climate is to their liking, as are the many endemic species they prey on. Should trends continue, Florida’s flora and fauna fifty or 100 years down the road will bear only a passing resemblance to the collection of plants and animals there before ground was broken on Disney World.
Not long after the particles of Great Plains dust that enveloped the marble monuments of Washington, DC, in May 1934 were swept away, steps were taken to avert a disaster that might have ultimately decimated America’s breadbasket. Americans have also banded together and rallied resources and brainpower to forestall other potential disasters arising from our often uneasy relationship with the natural world. At the dawn of the twentieth century, many people in cities along the eastern seaboard were contracting rabies from roaming packs of dogs. Lawmakers acted to mandate licensure and vaccinations and make it illegal for dogs to roam free. People’s attitudes changed about how they treated their dogs, and a legal remedy was created for removing roaming, infected animals from the streets. A similar shift happened with DDT. Thanks to Rachel Carson’s work Silent Spring we realized that DDT was threatening the future of many bird species—including eagles, falcons, and pelicans. It took ten years and hundreds of millions of dollars, but DDT was eventually banned. And the bird populations bounced back.
Te Papa Tongarewa (National Museum of New Zealand) is an impressive structure sitting above Wellington Harbour along the city’s waterfront. With hills in the background, a brewpub across the way, and the taller buildings of the central business district nearby, the setting is slightly reminiscent of San Francisco. Te Papa’s six floors contain exhibits dedicated to the natural and cultural history of New Zealand. In addition to the world’s largest specimen of the Colossal Squid (1,091 pounds and fourteen feet in length), these include a detailed exhibit on invasive species and their impacts, as well as specimens of New Zealand species that no longer exist. There are models of a Stout-legged Moa, which went extinct in the 1400s due to overhunting by the Maori, and a Haast’s Eagle, one of the largest known true raptors, which also went extinct in the 1400s, due to the extinction of its main prey, the Stout-legged Moa. On level three, in a slightly less prominent position than its larger extinct companions, a facsimile model of two Stephens Island Wrens rests inside a small glass case (fig. 9.2). The wrens are here because well-meaning lighthouse keepers brought a cat named Tibbles to an island. The cat—and its progeny—did what cats do: hunt and kill prey. Having evolved without predators, unable to fly and unable to fight back, the Stephens Island Wren was an easy mark. In a matter of a few years it was gone. Now and again, a boy or girl on a field trip who has taken a wrong turn in search of the squid may come upon these small birds—slightly comical-looking, with long beaks, long legs, and slightly ruffled light brown feathers—and read of their demise. He or she may or may not understand what extinction means, or that this is one of only a few examples of this little brown bird left in the world. The wren has been extinct for over 120 years, but it remains a gentle reminder of other species lost forever, thanks to the human introduction of free-ranging cats. Does this make us poorer as a people, as a nation, as a world? We think it does.
Today the actions of well-meaning people and, equally important, the lack of action on the part of others are having the unintended consequences of slowly unraveling the tapestry of our ecological well-being and threatening the health of people around the world. Inside, cats make excellent pets; loose on the landscape, they are—by no fault of their own—unrelenting killers and cauldrons of disease. With cats wandering the landscape it is not difficult to imagine a time in the not-so-distant future when your son or daughter enters a natural history museum and comes upon a small exhibit for a Piping Plover, a Roseate Tern, a Hawaiian Crow, a Florida Scrub Jay, a Key Largo Cotton Mouse, a Choctawhatchee Beach Mouse, a Catalina Island Shrew, a Lower Keys Rabbit, or any number of other species from islands and continents around the world—with the label “Now Extinct.”
ACKNOWLEDGMENTS
We are extremely grateful to several people for helping us improve various aspects of the book. For critical content as well as thorough reads of individual chapters we thank Stanley Temple, David Jessup, Robert Marra, and Scott Loss. Critical reviews of the entire book were provided by Chris Lepczyk, Scott Loss, Anne Perrault, Bill Thompson, and Grant Sizemore. Anne Perrault constantly challenged us to make sure we were fair throughout the book. A big thank you to many of our close friends and colleagues who were willing to be sounding boards, including Keith Carlson, Doug Levin, Matt Littlejohn, Ken Matsumoto, Dave Moskowitz, Kevin Omland, Geoff Roach, Janet Rumble, Sonja Scheffer, Scott Sillett, and Tom Will. Our literary agent, Danielle Svetcov, of the Levine Greenberg Rostan Literary Agency, has been a constant source of support on all aspects of the book. Thanks go to Robert Kirk for believing in the potential of this project, as well as to the rest of the team at Princeton University Press, including David Campbell, Mark Bellis, and freelance editor Amy K. Hughes, for helping to push this effort over the finish line. A special thanks also goes out to Tina and Andy Santella for preparing the many pizzas that nurtured our friendship in our early teens. Finally, we thank all animal lovers for their passion and, in many cases, their hard work on behalf of those who don’t have a voice in human proceedings. It is our hope that together those who care about animals can navigate a path toward equilibrium for all species.