Science

The Pandemic Is Giving Animals a Temporary New World

Our disappearance will affect food webs and reproduction—and then we will come back.

Group of pigeons on concrete, with downtown New York skyline in background
Getty Images Plus

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There are now so many lockdowns, shelter-in-place orders, and quarantines in effect around the world that half of global humanity is essentially indoors (minus walks). It’s all very weird for us, but the natural world is entering uncharted territory too. No, swans haven’t “returned” to the canals of Venice (they were always there), and no, elephants aren’t taking advantage of temporary human absence to get drunk and pass out on vacated farmland. Those, among other online reports of chaos in the animal kingdom, have largely turned out to be fabricated or oversimplified. Still, a significant shift is about to take place. If we really do live in the Anthropocene—an epoch of natural history defined by the effects of human beings on the planet—then a drastic curtailing of our activity (reduced air and car travel; our disappearance from streets, parks, and beaches; changes in hunting, fishing, and wildlife management practices) will have effects that are felt throughout nature. What are animals, and other wild things, going to get up to in our absence?

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It’s easy to imagine Jumanji-esque chaos ensuing—a mass exodus of scavengers out of beaches, parks, and shadows and into city streets. Fire escapes overrun by bands of raccoons, rats pouring out of subway stations. Desperate gulls and pigeons circling the skies, trying to steal food from garbage trucks and grocery shoppers. Maybe even hawks dragging small dogs to tree limbs and consuming them, leash and all, as shocked parkgoers gaze up in horror. In mythology and literature, visions of social collapse, crisis, and apocalypse have always featured breakdowns in the natural order. Locust plagues, swarms of rats, and ominous bird signs regularly accompany narratives of human calamity. It’s unlikely that all of these things will happen, but still, it seems safe to assume that we’ll see animals behaving strangely in the coming weeks.

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“It’s hard to predict what the effects are going to be,” explained Kaitlyn Parkins, senior conservation biologist for New York City Audubon, “because we don’t know how long this will last.” Parkins is in a unique position to imagine what the changes might actually look like; her work is heavily focused on the areas where people and animals exist in close proximity. Throughout the year, she facilitates wildlife surveys and other wildlife conservation and research projects around New York City.

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Some days, Parkins works at the Javits Center’s Green Roof, a 6.75-acre human-built habitat that rests above the convention hall that has recently filled up with men and women in uniform as the Army transforms it into a makeshift hospital. The Green Roof is the second-largest facility of its kind in the country. Thirty bird species and five bat species use it as habitat in some form or another. Herring gulls nest there in the summer, and the fledglings spend their first months flying to the river to eat everything from fish stunned by boat propellers to sandwich scraps left behind in Hudson River Park. “A lot of the human-animal interaction in the city revolves around food,” Parkins said.

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The animals that are most likely to undergo rapid, dramatic shifts in behavior when human beings go inside are also some of the most visible. In New York City, squirrels, pigeons, rats, raccoons, and a few gull species will have to adapt right away. In places where bears and coyotes are more common, those populations will also have to quickly recalibrate. Any animal that depends on human scraps for a significant portion of its diet will have to either find alternative local food sources or fan out to new places. “It’s interesting,” Parkins noted, “because a lot of the wildlife that tends to thrive in cities are generalists. They take advantage of any resource they can get, and have a lot of behavioral plasticity. That sets them up to be able to adapt to short-term changes in the environment quickly and easily.”

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In New York, that could mean moving to new places. The mass closure of restaurants and dramatic declines in subway ridership could force rat populations that inhabit those places to fan out and look elsewhere for meals. If parks close or empty out significantly, raccoons and squirrels will no longer be able to depend on the steady supply of food offered by public garbage cans. If public beaches abbreviate their seasons, the herring gulls and laughing gulls that spend the warmer months chasing down potato chips and other food left unattended by beachgoers will have to seek out a new food supply.

A rat wearing a crown crawls on a city street in front of a wall marked "Post No Bills"
Photo illustration by Slate. Photos by Getty Images Plus.
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It’s pretty clear where all those animals will need to go if they want to keep eating scraps. Although human garbage will disappear from some public spaces, people are still eating the same amount they were before. I thought about all of the cooking I’d been doing recently, and the pictures of home-cooked meals that my friends and co-workers had been sending me. “If there’s an influx of trash in residential neighborhoods,” Parkins said, “that’s a smorgasbord for rats.”

Parkins’ fiancé, Matthew Combs, is a research scientist at Columbia. He got his Ph.D. at Fordham University studying New York City’s rat population. The two of them had been discussing the possible outcomes for animals, particularly in urban areas. “Rats have among the closest relationships with humans,” Combs explained. “The first thing I started to think about is people who live adjacent to restaurants or above restaurants, where there are rats that have a daily habit of eating the trash that’s put out on the sidewalk every night. Rats like to stick to a routine, if it’s working out—exploring involves risks. But if those food sources dry up, they’ll likely start looking elsewhere. The properties that are adjacent will maybe experience rats coming to look for food.”

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The pandemic’s effect on the natural world could go further than rats coming out of the subways, though. Natural systems, when you look at them closely, are deeply interconnected. A year that produces a high yield of pine cones, for example, even in just a single area, can have ripples that lead to population spikes, changes in migration patterns, and habitat realignment for multiple species across vast areas for more than one season. “We can make predictions based on what we know about wildlife,” Parkins said, “but the urban system is more complex than we realize.” Animals have learned to adapt to and make use of human behavior in countless ways, from the birds that follow fishing boats out to sea, to the peregrine falcons and red-tailed hawks that nest on bridges and skyscrapers, to the eels that writhe through our sewers.

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One of the most significant human-made impositions on wildlife, our highways and streets that hum constantly with traffic, is about to empty out as travel declines dramatically. “Roadways, cars, and traffic have the ability to contain wildlife in particular places,” Parkins said. “An animal might have to be really brave to cross to the next habitat.” As those barriers come down, animals will suddenly find their movements less inhibited, as footage from Wales showing Kashmiri goats romping through the empty streets of a small town called Llandudno demonstrated. Ranges will expand, and some animals that were suffering from constricted habitat might find themselves in a more secure situation. It sounds delightful, but it’s a dramatic change that will come on quickly. Imagine all the animals in a zoo waking up one day to find that the walls and bars had disappeared overnight. There’s a kind of pastoral beauty to imagining herds of deer roaming freely across the highway system to graze in backyards and public parks, sure. Just remember that roaming deer mean coyotes and bears could also be less inhibited.

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Indeed, every animal exists in the wider food web. In urban settings, rats, squirrels, and pigeons are prey for larger animals like feral cats and raptors, which might have to adjust their behavior as their food sources fan out. A change in behavior even in a single species could set off a chain reaction that affects animal behavior in countless unpredictable ways. There are a dizzying number of moving parts, all of them connected in a giant chain of causes and effects that are nearly impossible to predict. A large population of white-tailed deer, for example, can devastate a forest’s understory by grazing on low-lying plants and saplings. Even a modest population bump from a reduction in automobile collisions could set back woodlands for years to come.

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There are other species that might stand to benefit, at least in the short term. If public beaches don’t fill up this summer, shorebirds that nest there will likely have a better breeding season than they would otherwise, with thousands of miles of new habitat suddenly available to them when they arrive. Birds and mammals that are highly sensitive to noises or susceptible to being killed by car traffic will probably fare slightly better too. There are hints that things are already starting to change. A credible-seeming news report from New Orleans described an emboldened rat population leaving the shadows to scavenge out on Bourbon Street. A video shot in Thailand showed dozens of monkeys in a near-empty tourist square brawling over a single container of yogurt. The oldest national park in Africa—Virunga, in the Democratic Republic of the Congo—closed its doors to tourists out of fear that the virus, like other similar viruses, could make a leap to the dwindling populations of great apes that survive there. It’s hard not to feel like these are tremors of things to come—a realignment in the way animals interact with the world that will match, in some ways, the extraordinary intensity and insanity of what’s unfolding in the human world every day.

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Still, it would be idiotic to indulge in the fantasy that human beings going inside for a few months will somehow allow the natural systems we’ve damaged over centuries to “heal.” The wear and tear of human behavior on wildlife has been long-term and extensive. Many of the ways humans affect wildlife are more permanent than us scaring them into staying put or accidentally feeding them with our trash. When I first met Parkins two years ago, she was leading a training for volunteers with Project Safe Flight, NYC Audubon’s initiative to research and document bird collisions with windows in the city. Birds, she explained at the time, perceive the world differently than human beings do. Reality comes at them all at once, a constantly moving set of spatial reference points. Building glass, which can confuse them by reflecting images of clear sky or nearby trees, kills somewhere between 90,000 and 230,000 birds in New York City each year. There’s no reason to suspect that those collisions will decline just because humans are inside. A day after we spoke, in fact, Parkins sent along a photo of a dead golden-crowned kinglet that she’d watched collide with a window near Central Park.

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A picture of a dead bird would have made me upset a month ago, but now a window strike seemed like a reassuring sign. All around the world, animals are still participating in their normal habits, which right now means migrating up toward breeding habitat. Seals that haul out in Staten Island and the Bronx in the winter are swimming north with dolphins, porpoises, and whales, as they do each year. Striped bass and Atlantic sturgeon are surging up the Hudson River to spawn. New York City’s terrestrial spaces are about to be inundated with what might be the most remarkable natural phenomenon in this part of the world: the rapid arrival and departure of millions of birds in a two-month period.

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Our disappearance from the world is happening at a time of massive flux for creatures. This might have its own set of influences. Our abrupt retreat inside was preemptive, a reaction to information from scientists and journalists about an event we knew was coming. Animals don’t have newspapers or epidemiologists to tell them how to prepare; they’re still just out there, migrating, hunting, trying to survive. It’s one of the reasons their reactions are so difficult to anticipate. Just like us, wildlife is at the beginning of this crisis—they just don’t know it yet. While we get guidance from political figures and doctors, animals will respond with reflex and instinct. And even as they adapt to us being gone, they can’t realize that, eventually, we’ll come back. Which means that despite modest benefits that might reach specific populations due to our absence, there’s no reason to believe that the factors that initially put stress on those animals won’t come roaring back whenever people head outside again.

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My best guess is that there will be dramatic developments in the coming weeks—reports of animals spreading out into new areas to explore habitat options or look for food. Some will become aggressive or behave in other strange ways. Human beings and bears will come into closer contact than either species is accustomed to. It might be a systemic unraveling, or a modest shift, or a series of isolated, temporary incidents. Combs and Parkins were cautious with their predictions—careful to mention that they can envision scenarios where little changes. I can’t help but imagine the extremes: the Boschian nightmares where primates stop traffic to tip over trucks full of food and gulls invade homes and grocery stores, Hitchcock-style. Natural systems are incredibly intricate, and it’s almost impossible to predict exactly how they’ll respond.

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Recently, with all this in mind, I picked up my binoculars and went out for a long walk through Manhattan and along the Hudson River. House sparrows were beginning to form nests inside the metal fixtures that hold up traffic lights. I saw a red-throated loon bobbing in the wind shadow of a hulking dinner boat at Pier 60—a locally rare bird that made me wonder if the reduction in boat traffic had already made Manhattan’s shoreline a more inviting place for solitary animals. None of this was scientific, of course. I was projecting the human crisis onto the natural details around me. Still, I couldn’t help but feel that something was going on—that I was witnessing the early moments of what might turn out to be sea change. There was a cache of emptied acorn lids on the sidewalk, dug up and devoured, and I imagined the squirrels of Hudson River Park panicking at the sight of empty garbage cans and gnawing through their savings all at once. As I was getting ready to leave, a red-tailed hawk caught me off guard. It was staring from the top of a chain-link fence a few feet away, ignoring the rain the wind. It was well within the 6-foot bubble that I’d been keeping between myself and other people—closer, in fact, than any hawk had ever let me get. We looked at each other for a long minute before a car horn from the Westside Highway scared it out over the river.

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