From the beginning, I knew that I wouldn’t necessarily succeed in imposing my enthusiasm for neighborhood nature on my daughter, and that my efforts might backfire. So, when Josephine became fascinated with the color pink, told me that my squirrel-spying walks were a little boring, and wanted to talk most of the time about what it meant to be a girl, I wasn’t too disappointed.
“When I grow up I’m going to be a fairy, princess, ballerina,” she would tell me.
I couldn’t resist subtly slipping in “scientist” at the end of that litany, but I never pushed it any further than that.
By the time I had decided I needed to take a closer look at crows, Josephine was in full-throttle fairy-princess-ballerina mode and totally uninterested in the birds. That was all right, I decided. I never meant to force her to share my interests, I had just wanted to demonstrate to her, and to myself, that my nonhuman neighbors are important by paying attention to them.
It was the raptors that led me to crows. The story of the return of the raptors is fairly well known at this point: Ospreys and peregrine falcons were killed off in large numbers by organochlorine pesticides like DDT, but after use of these chemicals was restricted, they bounced back. These birds aren’t invisible; some have adoring fans and webcams trained on their nests. Whenever I see the characteristic shape of a bird of prey, I look up eagerly. And it was in one of these moments that I began to see crows.
At first I assumed that both of the birds I was watching sail across the sky must be raptors. They crisscrossed my field of vision, disappeared behind the houses, then circled back. One was smaller and faster; the other was a red-tailed hawk, flapping ponderously. On the next pass there were two of the smaller birds. They were low enough now that I could see that they were black. The smaller birds weren’t falcons or hawks, they were crows, and they were molesting the bigger bird mercilessly.
In San Francisco we lived at the foot of a tall, grassy hill—a good place, if you are a raptor, to find voles and other small rodents. I often saw hawks hunting there. I also saw crows ganging up on larger birds of prey. The crows made the bigger birds look positively clumsy. They’d swoop and turn in a fraction of the time it took the hawks to flap their wings. This behavior is called mobbing, but initially I could find no satisfactory explanation for why they do it.
Were the crows trying to keep the predator away from their nests? That seemed to make sense until I realized that I’d seen crows chasing hawks in the winter, when crows have no nests. The opposite could be true: The crows might be after the raptor’s eggs. But why choose such dangerous food when there are pigeon eggs everywhere? That’s like searching for tyrannosaurus eggs while surrounded by chickens. The crows, I learned, occasionally get just a bit too close to the birds of prey, which quickly kill them.
The crows may have been trying to steal something the bigger birds had killed. They do this sort of thing all the time, employing a two-crow con. Naturalists have observed one crow walking toward an eating eagle with feigned disinterest, just drifting closer nonchalantly. Then another crow will dash in from behind and pull the eagle’s tail, causing it to leave its meal and give pursuit. The first crow darts in and snatches a piece of the kill, which it later shares with its accomplice.
None of these explanations, however, accounted for the fact that the crows I saw often harassed raptors for half an hour, maybe more. I would lose interest, carry on with my errands, then look skyward as I stepped out of a shop to see them still at it. You don’t need that kind of time to steal a mouse.
I began to think of this differently after I read Gifts of the Crow by John Marzluff and writer and illustrator Tony Angell. Marzluff researches corvids—a family that includes crows and ravens—at the University of Washington, and he’s written several books with Angell. They note that there’s a direct evolutionary benefit to mobbing when it keeps predators from pillaging nests, but suggest that there’s something more at work here. Mobbing looks a lot like a product of a culture, they write. “As a social exercise it provides a forum within which individuals can display their flight skills and aggressive tendencies. Not unlike the human recognition for a demonstration of valor, these attributes may win a daring crow a mate, or a higher rank in its avian hierarchy.”
Among the Maasai, an adolescent boy used to have to kill a lion to earn his place in the patriarchy, and it’s not so crazy to think that crows might earn status by challenging a larger predator.
Or maybe instead of earning status, they are just having fun: their version of extreme sports. Perhaps they do this aerial dance with death for the same reasons that humans do ostensibly pointless things like big-wave surfing or mountaineering. I like to imagine that crows are doing it out of sheer delight, for the joy of besting a force that could easily crush them.
That’s not as fanciful as it sounds. Ravens have been observed “surfing” the wind by holding flat pieces of bark in their claws and riding mountain updrafts. They use bits of plastic to sled down snowy roofs, ride rotating sprinklers, and slide on their breasts down the onion-domed cupolas of Russian Orthodox churches (helpfully polishing them in the process). Angell and Marzluff once spotted an airborne group of crows playing with a ball of paper above a University of Washington football game. One crow would carry the ball a few wing lengths and then drop it, at which point the others would dive in, the fastest one snatching it from the air. They repeated rounds of this corvid quidditch over and over again, causing attention in the stands to stray from the earthbound athletes. And at the University of Montana, a crow learned to gather up small packs of dogs by whistling and calling what for all the world sounded like “Here, boy!” The bird would lead the dogs on frenzied chases across campus for no apparent reason.
To say that animals play strikes some as dangerously speculative. If you think of an animal as a Cartesian machine—a complex wetware robot that responds mechanically to a stimulus—it’s hard to imagine why it would play. How could evolution tolerate frivolous risk and use of energy? But there’s a clear scientific consensus: Animals do play, and crows are among the most playful.
“Many birds play,” Angell and Marzluff wrote. “But no group of birds has been reported to play as frequently, as variably, or with as much complexity as the corvids.”
This doesn’t disprove the Cartesian argument, it only proves it’s wrong in drawing a distinction between animals and humans. The more valid and interesting question is this: If we are all just complex machines designed to reproduce and pass on our DNA, why does anyone play?
People used to think that natural selection favors play when it provides valuable training; in crows, for example, mobbing might teach agility and build muscles. This makes intuitive sense, but scientists have found it doesn’t work that way. Researchers have tested this out with mice, coyotes, kittens, squirrels, bears, and rats. They found that the individuals who played were no better at hunting or fighting than those who didn’t. The behavioral ecologist Lynda Sharpe spent years watching meerkats tussle; to tell them apart during the rollicking melees, she had to sneak up to them as they napped and draw on them: “I’d crawl around the group on my stomach, clutching a fistful of marker pens and surreptitiously scribbling coloured rings on everyone’s tails,” she wrote. But after analyzing her data, Sharpe found that participating in this “training” had no relationship to success in real fights.
And yet, the play does do something: Research shows that animals that play are more likely to survive, and become better parents. Rats—one of the most playful species—that are deprived of play react to minor conflicts by flying into a rage or quaking in a corner.
“There’s something about play that increases overall fitness, but it’s not about hunting or fighting,” said Kaeli Swift, a researcher who studies crows with Marzluff.
The definivite reasons for play are still mysterious. It’s clear that play is simply fun; both crows and humans experience a flush of opioids in the brain when they play. But we don’t know how this proximate cause of playfulness—the thrill of experiencing joy—leads to its ultimate cause, which is increasing reproductive fitness.
It’s also clear that there’s a social reason for playfulness. Play is a way of making meaning of the world. It provides an opportunity to act out aspirations (as children do in playing make-believe), reaffirm tribal unity (as fans do every day in stadiums around the world), and pass on a moral education for managing conflict. Perhaps mobbing is a dangerous ritual affirming the culture and solidarity of a crow clan.
Marzluff is probably most famous for showing that crows can recognize individual people. In 2002, he trapped a crow and slipped three plastic rings over its ankles—two light blue and one dark blue—to help him identify the bird. It turned out that this crow was Marzluff’s neighbor, and whenever the bird saw him, it would caw wildly, castigating him and warning others that there was an evil crow grabber on the loose, one capable of inflicting his dubious fashion judgment upon his victims’ ankles. This went on for more than seven years. Marzluff noticed that he always got this abuse no matter whether he was wearing a parka or a short-sleeved shirt, no matter whether he was alone or with a friend, no matter whether he was walking or driving his truck.
It seemed like the crow could recognize Marzluff’s face, but of course it could have been something else: his scent, the curve of his shoulders, the particular cadence of his walk. So Marzluff bought a Halloween mask of a bald and bucktoothed caveman with a massive ledge of forehead hanging over the eyes and had his students wear it while capturing birds at the University of Washington. Sure enough, after that, whenever anyone wore the mask the crows would go crazy. Just to make sure they hadn’t accidentally discovered that crows simply hate disguises, Marzluff got an even more terrifying mask—one that looked like former vice president Dick Cheney—and walked around campus with it on. The crows had no quarrel with Cheney, but continued to harass anyone who wore the caveman mask.
It was a tremendous feat to prove that crows recognize human faces, but what happened next was, to my mind, even more extraordinary. More and more crows flocked to scold the caveman, and some of these crows had no leg bands. “Not only was the crows’ hatred of the caveman persistent,” Marzluff wrote, “it was getting worse with time. . . . The number of birds scolding the caveman on a typical walk has increased threefold. And the vast majority of those who berate the Neanderthal were never even touched by him.”
Crows were teaching each other to fear this bogeyman. This has been going on for eight years, and there’s no sign they will forget the grudge. People who learn about this research are often captivated by the masks and fixate on the fact that crows can recognize individual people, Marzluff says. But the ability to see and remember visual markers in a face is a relatively simple cognitive task. Wasps, for instance, have it down pat: They identify one another by their facial markings. Dogs, monkeys, and pigeons can also recognize individual humans; so can sheep, honeybees, and even octopuses.
I think it seems strange to us because crows are doing something that we can’t: differentiating the members of the other species. Most people can’t differentiate individual crows. It’s actually more correct to say that we don’t recognize individual crows, instead of saying that we can’t. Our face blindness is self-imposed, because we could see the differences between crows if we actually looked. After all, pet owners quickly learn to recognize their pets even when they’re with others of the same breed.
To focus entirely on crows recognizing faces is to miss the most astonishing thing that Marzluff discovered: Fledglings learned to fear the caveman in the abstract. The young birds never actually saw the masked man capturing other crows, they had only seen their parents scold him. One generation passed the information to the next: This momentous thing happened to our kind. Learn it. Never forget it. Teach your children. This transmission of information is challenging enough that only the most intelligent creatures can manage it. It allows for the formation of tradition. In fact, it seems to me that if you take the same phenomenon and perpetuate it for thousands of years, you have something that looks very much like a religious observance. What are seders or the rituals of Christmas but means of perpetuating deep cultural memories? Perhaps those crows I saw mobbing red-tailed hawks were not showing off or playing, but instead reenacting an ancient ceremony so laden with meaning that I could not hope to understand it with simple evolutionary explanations.
There’s a clear evolutionary advantage in being able to differentiate one person from another when one of them will try to shoot you and the other will feed you peanuts. Crows use their facial recognition ability to torment those who cross them, and also to reward those who help them. They sometimes leave little gifts for friends. Angell and Marzluff report that on Valentine’s Day of 2006, nature writer Gary Clark jokingly asked the crows he regularly fed why they never brought him anything in return. Later that day, when he returned to retrieve his feeding tray, he found a candy heart placed exactly in the center with LOVE printed on one side. Surely the timing of this gift—and the message it bore—was coincidental (no scientists think crows can read), but lots of people have received gifts from crows after feeding them.
Those who anger crows, on the other hand, suffer creative retribution. Carolee Caffrey, a zoologist at Oklahoma State, has described a crow expertly bombarding a student with pine-cones. The student was climbing a tree to study the crow’s nest, and the crow plucked three pinecones and dropped each on the student’s head.
In another story collected by Angell and Marzluff, Seattle resident Gene Carter earned the ire of his neighborhood crows by scaring them away from a robin’s nest. After that, a crow scolded him every morning and evening when it spotted him walking to and from his bus stop. The bird would dive toward him threateningly, “occasionally rapping him on the head, always amusing his wife and fellow commuters,” they write. This went on for a year, until Gene moved to a new house. He was careful to move each load of his belongings to the new residence by a circuitous route to avoid being followed, immediately giving up and turning back if he saw a crow.
I found that crows are a bit more difficult to observe carefully than some of the other species I’d begun to watch in writing this book. Crows are liable to fly off: They’re not wedded to any one spot. And they are aware, and suspicious, of observers. When I watch them, they watch me. I don’t need to take a single step toward a group of crows to arouse their vigilance, it’s enough just to stop and stare at them instead of continuing with the flow of foot traffic. Pigeons are glad for human company and seek our patronage. Easily distracted squirrels quickly forget that you are there. To ants, we are incomprehensibly foreign. And to ginkgos our lives are insubstantial shadows, flitting past. But to crows, we are peers. They know better than to trust us, and unless there’s good reason to share, they keep their secrets to themselves.
One soggy Sunday afternoon as Josephine and I walked to the grocery store, Josephine pointed out a pair of black shapes on a rooftop, their profiles sharp against the iron-gray sky. The crows were dipping their beaks into the roof’s gutter and plucking something out, but it was impossible to see what it was with the naked eye.
They went about their work with the busy economy of motion of farmworkers harvesting a row of crops—though these farmworkers stopped every few seconds to watch the large carnivorous creatures who stood watching them. One crow fluttered to the next roof over and began working its gutter. I speculated aloud that there might be fat grubs living in the gutter leaf litter. Josephine suggested it was more likely that the crows were eating chocolates. Later, Swift would tell me that Josephine’s guess might have been closer. She often uses Cheetos to gain crows’ trust, and they love to hide these treats—and other food—in gutters.
The crows pecked busily. Then they flew away: darker wings against dark clouds.
The blackness of crows fairly radiates from their feathers, which impressed itself upon me when I took my lunch to a park one day. I found a seat near a pair of crows perched in a tree. One of the birds had a white streak on the underside of one of its tail feathers. I thought at first that this was a guano stain, but it didn’t look like it: It was very pure white, not clumpy or streaked. When I checked into it later, I learned that many birds do indeed lack pigment in a few feathers.
I watched my white-streaked crow (and it watched me back) while I ate a quesadilla and wondered, Why black?
Lyanda Lynn Haupt, in her book Crow Planet, described crow colors in detail after she spent two full days staring at one on her desk (a stuffed scientific specimen) to see if she could open her eyes to something new. She noticed that the innermost half of breast feathers—the part usually covered by other feathers—was gray and explained, “It takes some biological effort to produce dark pigmentation, and if it is not needed because the feathers are not visible, then natural selection does away with it.”
Basic pigmentation must be pretty cheap (biologically speaking), or else creatures without coloring or patterns would be everywhere. But I could imagine that producing that deep, silky blackness does demand more resources than gray does. You can glimpse the gray when the wind disturbs the breast of a crow.
If blackness is biologically expensive, what are crows (and blackbirds, and ravens) getting in return for paying this premium? Nobody knows for sure, but there seems to be a provisional consensus among ornithologists that the blackness allows the birds to be seen.
Many animals are patterned for camouflage: Any variation in color helps break up the profile of the creature. If a tiger is creeping up on me through the jungle, for instance, instead of seeing a solid block of orange in the shape of a tiger, I’ll see stripes of orange and black, which would be easy to misinterpret as branches, shadows, and shafts of light. Pure black, on the other hand, stands out against almost all of nature’s backgrounds. There’s no misinterpreting the shape when it’s all one color. This visibility is helpful for social birds like crows because it allows members of a group to see each other clearly. An individual crow is puny, but a murder of crows can chase off eagles—and drive grown men to change their addresses.
Even an all-black dress code can contain further complexities. After staring at her crow for hours, Haupt noticed that “the black glossy feathers on the crown and back are outlined with iridescent violet, giving them a scaled appearance.” This contrasts with the feathers on the back of the neck, which are flat black. The small body feathers, Haupt wrote, are “as soft as rabbit fur,” while the wing and tail feathers are stiff.
Here is how I try to tell if I’m looking at a raven or a crow. If the bird is flying, I look at the tail. Crows have a rounded fan. Ravens have a diamond-shaped tail. I also watch the bird closely when it lands. Ravens are quiet and still. Crows fidget and complain. Their voices are different, too. Crows “caw” abrasively. Ravens “rawk” in the pebbled baritone of a woman who has tended a smoky bar for thirty years.
Once I have a pretty good idea, I look for other features to confirm. Ravens are bigger, and they have thicker beaks and a luxurious beard of feathers on the neck. Crows are slimmer: gracile, sleek. The average raven is two and a half pounds to the crow’s one pound, but it’s hard to judge that unless you have the two side by side. Really, though, I identify crows mostly by knowing that ravens are rarer in my neighborhood, so any big black bird I see is probably a crow.
Ravens live just about everywhere on Earth, from deserts to the soggy northwestern coast of America. Crows are a little more particular: They like to be near people. In fact the Asian house crow seems to live only in the company of humans. You could call them obligate synanthropes: They depend on us for their habitat.
Crows do well in the landscapes we create. They like farms, from which they pilfer grain. They like lawns, where they find worms and crane flies. They like bird feeders and bags of garbage and roadkill. Humans supply it all.
One winter, the online news organ in my town, Berkeleyside.com, ran an article on the local multiplication of crows. People had noticed, with some alarm, that every year there were more of them. When the Audubon Society conducted its annual bird counts in the 1980s, there were always fewer than a hundred crows tallied, and just a handful of ravens. After 2010, the birders were regularly counting more than a thousand crows, and as many as three hundred ravens. There are reports that the same is true in other cities.
I hadn’t lived in the area long enough to witness the increase myself, but I had noticed the crows out in force. When I run in the park every morning, there are always small groups of black figures patrolling the grass. Every once in a while I’ll follow a bird’s line of flight to a tree harboring dozens of crows.
People were worried that the crows must have come at the expense of biodiversity. Crows sometimes rob the nests of other birds to eat the eggs and chicks. Would the increase in crows lead to a crash in songbird populations?
Kevin McGowan, a corvid researcher at the Cornell Laboratory of Ornithology, said that wasn’t likely. When researchers put cameras on nests to catch robbers, they found that the culprits usually weren’t crows, they were squirrels or snakes. Crows, McGowan told Berkeleyside, “are way down on the list,” behind raccoons, raptors, opossums, and jays.
Eventually, if the population of crows grows large enough, it can affect the system, Marzluff told me. But the birds that feel the impact also thrive around humans, like robins and jays. The threat to biodiversity comes not from crows, but from humans making drastic changes to habitats. Furthermore, people have tried getting rid of crows, and scientists have watched to see if it helps other birds. To put the findings simply: It just doesn’t work.
I suspect that the dismay accompanying the rising number of crows stems from the sense that every addition to the natural world results in some equal and opposite subtraction. Crows are humanlike in their creativity and their ability to thrive in the ecosystems we shape, so their presence looks to some observers like an extension of human disruption. We lay waste to the earth, and then crows take advantage of the changes and elbow their way in. From this perspective, the booming crow populations look like diminishments of nature.
The evidence, however, doesn’t support this fear. In 2012, ornithologists at UC Berkeley dug up dusty bird surveys dating back to 1913 and compared what they reported with the species they saw on campus. They expected to see a decline, a steady fall from Eden, because so many buildings had gone up on campus, the surrounding area had changed from farms and pastures to an urban grid. But instead, the researchers found a small increase in bird diversity over the century.
Across North America, crow populations are increasing, though much more modestly than by the full order of magnitude seen in Berkeley and other cities. Meanwhile, overall bird diversity has stayed steady. In the United States, the Environmental Protection Agency found that 113 bird species have suffered significant declines in the last half century. But at the same time, 118 species have benefited from significant increases in numbers.
There’s one more question embedded in the observation that crow populations are increasing. That question is: Why are the biggest increases in cities?
The answers are slightly different across America. The American crow isn’t endemic to the West Coast, it followed suburban developments across the United States, glorying in the irrigated lawns that turned the inhospitable West into ideal habitat. They reached the West Coast sometime around 1960, Marzluff said. Part of their increase in western cities is attributable to their colonization of new land.
In eastern North America the most likely explanation for booming urban crow populations is that they are moving from the countryside into towns. And we know with certainty that this is happening. By doing a little historical research, McGowan found that at least one roost had moved from three miles outside the town of Auburn, New York, in the 1930s to the middle of town. And many other cities—Pittsburgh, Albuquerque, Minneapolis, and Ottawa, Canada—have seen roosts develop.
A roost is a great congress of birds gathered for the night. Starlings and nuthatches also roost, as do robins, though in lesser numbers. Crows often roost together through the winter, then separate in the spring to build nests for eggs. These roosts can grow stupendously large. One, in Fort Cobb, Oklahoma, had around two million crows. McGowan describes standing beneath a roost of more than fifteen thousand crows in central Ohio and marveling at the volume of excrement underfoot. Crows, like many birds, swallow bits of rock to help break down the grain they eat, and McGowan estimated that the crows in that particular roost could drop 1,650 pounds of gravel around that tree every five months.
If there are more roosts moving into cities, then it stands to reason that crows are staying in towns during the day as well. But why have they moved?
Maybe it’s because there are laws against firing guns within most cities. Now that we are no longer primarily agrarian and scarecrows are a symbol rather than a practical tool, we don’t see crows as our enemies. And vice versa: Crows may have simply gotten more comfortable being surrounded by humans all the time. Marzluff notes that city crows tend to be much less skittish around people, and more likely to aggressively scold humans.
McGowan suggests that the move to cities might also have something to do with the invention of streetlights. Great horned owls are the most effective predator of crows, swooping in noiselessly from the dark to grab them. But few owls penetrate to the city centers, and with the glow from the streetlights, the crows have a chance to see them coming. (Crows, like most birds, can’t see very well in the dark.)
McGowan also says that crows are roosting in cities because that’s where the trees are. The grand old trees in parks and cemeteries are often the largest trees around, the only ones to survive the most intense period of logging and development. Since the early 1900s, urban forests have sprung up. If you look at pictures of American cities from a century ago, you’ll find many streets were treeless. By foresting along the sidewalks, we’ve created a habitat that simply didn’t exist before, a massive surface area composed of branches for nesting and perching. The leaves and berries, the insects that feed off them, and the spiders that eat those insects are all in turn the food for birds and other creatures.
I find all this tremendously heartening. Instead of being a symptom of human destruction, crows seem to be moving in because, at least for them, we are improving the habitat. In his book Welcome to Subirdia, Marzluff tells how he spent two weeks birding in Montana’s Glacier National Park, then flew to New York and went out bird-watching in Central Park. He was surprised to discover that in New York, he saw a greater diversity of birds by midday than he had during his entire stay in Glacier National Park. The science supports his experience. Studies have found there is very low diversity in bird species at the concrete core of a city when there are no nearby parks. The biodiversity of remote woodlands is higher than that. But the greatest number of unique bird species can be found in cities that have big parks.
Human density can go hand in hand with biological diversity. Our civilization is not always a force desolating the earth.
That doesn’t mean that those trying to preserve wilderness are misguided or that we should be building condos in Yosemite. We need remote areas to support all the species that don’t thrive alongside humans. The point is that the places where people live, if thoughtfully designed, might also be places for the rest of creation to thrive.
Marzluff would like to see cities located near at least a hundred acres of dense forest, ideally consisting of native vegetation and abutting a waterway. Berkeley, for instance, which researchers found has a wide variety of species, borders a two thousand–acre wooded park.
I believe bringing people together with other species is beneficial, even for people who aren’t nature lovers. Evidence shows that stress levels drop and health improves when people are in the company of plants and animals. If we care about biodiversity and want to experience it personally (in addition to knowing it exists somewhere else, thousands of miles away), it’s eminently possible to increase the species richness of our daily lives by nurturing a variety of habitats in and around cities.
Here’s another potential explanation for the rise of crows in cities: More people make more crows. Marzluff estimates that the territory a nesting family of crows controls is about the size of two backyards. That’s about one crow per person. This equation breaks down as density increases and backyards disappear under skyscrapers. But when a city is dominated by freestanding homes, an increase in population usually means more lawns and more garbage, and therefore more crows.
The attributes that allow crows to thrive in our company also make them interesting. They are innovative and flexible. They pay close attention to us, read our body language, and anticipate our intentions. Neuroscientists studying crows have shown that they can quickly and accurately infer the cause of an unexpected event. They also, like humans, can make mistakes about what causes what; in other words, crows can develop superstitions.
Sometimes they seem to toy with humans. Angell and Marzluff tell the story of a crow pilfering a sandwich from golfers and then returning the empty sandwich bag to them two holes later. Another pair of ravens stole a pie from sea kayakers, then bombed them with the pie tin the following day.
Crows use humans. They drop nuts and shellfish on roads to be smashed by our high-speed steel-belted radial nutcrackers. At certain intersections in Japan, it’s common to see crows tossing nuts into the road, waiting for the signal, and then walking with the pedestrians to retrieve their reward.
The birds quickly adapt to our ways. In the 1950s, when cars started zipping down the highways, crows would fly away from the sides of the road whenever a vehicle passed. By the 1960s, they were barely flinching as cars zoomed by.
New Caledonian crows, which have the largest brains among crows, use and even make tools. For example, they carefully trim twigs into hooks to excise insects from tight cracks. Some behavioral ecologists were skeptical of the amazing feats reported to have been accomplished by New Caledonian crows until researchers filmed one, Betty, using tools to lift a basket of food out of a cylinder. It’s an astonishing video. Betty first attempts to spear the food with a wire the researchers had provided. She considers a moment, then wedges a rod under a rock, deftly bends it into a hook, and fishes out the food. Betty does this nimbly, without a misstep. This video demonstrated that the crow is able to think three steps ahead: First, Gosh, it sure would be a lot easier to get the food if this rod had a curved end; second, Maybe I could bend the rod to make a hook; and third, I could use that rock to bend the rod. These birds are amazingly clever. To raise the bar, researchers devised an experiment in which the crow would have to pull up a string to retrieve a short stick, then use that stick to retrieve a longer stick, and then use the longer stick to get a piece of meat. The crow did it on the first try.
American crows are not as clever as New Caledonian crows, but they are still very smart. Researchers compare their level of intelligence to that of primates. “They’re like little flying monkeys,” Marzluff said.
In at least one way, though, American crows are considerably more resourceful than humans. Crows have exercised their considerable intelligence to exploit human quirks—our wastefulness with food, our reflexive desire to carpet outdoor spaces with grass, our predictable driving habits—but humans have devoted no thought to how we might take advantage of the rise of crows in our midst. Why are we the stupid ones in this relationship?
This question has obsessed Josh Klein for nearly a decade. Klein is one of those Information-Age Renaissance men who not only ponder crazy ideas, but also take the process a step further by engineering those ideas into existence. Klein’s ideas for making the relationship between humans and crows more reciprocal began in the form of a vending machine: He built a box designed to produce a peanut every time a crow inserted a coin. Then, working with a crow trainer, he demonstrated that the birds could learn how to find coins and exchange them for food.
When people hear about his crow box, Klein says, many tell him he’s going to get rich. He’s not optimistic about making money; he just wants to make the relationship between humans and crows a mutually beneficial one. He’s disturbed by the fact that very few people have noticed that some animals have changed to thrive with modern humanity. It’s not just crows, but raccoons, rats, deer, turkeys—by some estimates these species have larger populations than ever existed in North America before. “We have these animal populations evolving to take advantage of us,” Klein told me. “We can’t kill them off. And we aren’t doing anything to make it a more productive relationship. We are effectively breeding them for parasitism. I think it could be disastrous.”
The crow box is Klein’s contribution toward establishing a more balanced relationship. When I spoke to him, Klein said that he was redesigning the crow box because it had proved too difficult for some of the beta testers. I assumed that by “beta testers” he meant the crows and asked what it was about his machine that had been hard for them. He quickly corrected me: The crows were doing fine, the problematic beta testers were humans who had struggled to set up the machines. “Asking what about the crow box makes it hard for crows is like asking, ‘What about your front door makes it hard for your teenage son to use?’” he said. It’s clear that crows can work the vending machine; tame birds were ready to exchange money for peanuts after watching Klein set it up and test the box. But just because a teenage boy knows how to operate a front door doesn’t mean he’s going to be interested in coming home every night for a family dinner.
For crows, the mechanics were easy, motivation was much more complicated. After one crow learned how to work the vending machine, it began to hide the coins rather than inserting them for peanuts. Instead of being compelled to action by a reward of a peanut, it seemed to be compelled to watch the spectacle of its human colleagues searching furiously for the coins. Another time, Klein was training a crow using raw hamburger—to a crow, a more enticing reward than peanuts. While no one was watching, the crow hid some of the meat in Klein’s jacket pocket.
“When I was getting ready to go I put on my jacket, put my hand in my pocket, and screamed like a little girl,” he said. “The owner of the crow laughed his ass off, and the crow—they make this caw-aw-aw call that sounds like laughing.”
The very next time they met for a training session the crow snuck into the bathroom, stole some toilet paper, wet it in the toilet water, and cached it in Klein’s jacket pocket. When Klein put on his jacket and felt the wet mass, he jumped again, then gaped at the complexity of the practical joke.
There’s no doubt that crows can operate Klein’s vending machines if they want to, but it may turn out that they simply find it more entertaining to live off human excess than to work for peanuts. Whatever ends up happening with this project, in my opinion, it’s already a success. No matter how efficiently it hacks the behavior of crows, it has already hacked the behavior of humans. Klein gets e-mails weekly from people who have heard about the crow box and want to know more. It’s snapped people out of their normal pattern of ignoring animals until they become a problem that can no longer be ignored. Klein is not going to single-handedly put us on a path to coevolutionary harmony with crows, but I do think he’s taken the right first step by replacing ignorance with curiosity and attention.
Though I’ve been looking, I haven’t managed to find a crow’s nest. They prefer conifers, Marzluff told me, because evergreens provide year-round cover. It’s apparently easy to mistake a squirrel’s nest for a crow’s nest. “Actually, squirrels’ nests typically start off as crows’ nests,” Marzluff said. But squirrels like to use leaves and pine needles, and crows prefer sticks. In addition, crows use grass whereas squirrels don’t, so McGowan looks for grass sticking out of the bottom of a nest.
In the spring, a mated pair will lay down a crosshatch of sticks (although in Tokyo, where coat hangers are more abundant than sticks, crows sometimes use those instead). Then they’ll add mud and grass. Finally, the female will line the nest with some soft and comfortable material.
Sometimes the offspring born the previous year will help with nest building. They stick around until they reach sexual maturity between the ages of two and four. Crows are different from most other birds in that the males sometimes stay even longer than that, until well after they are capable of starting their own families (the females, in contrast, always leave). They assist with feeding the next generations and cleaning up the nest.
The eggs range from sky blue to aquamarine, and are flecked with brown. Crows keep the nests clean by tossing out the chicks’ scat until they grow large enough to poop over the edge.
The chicks are ridiculous. They slump in the bottom of the nest as if they are dead, like sagging black assemblages of skin and delicate bone. But then, whenever there is a noise—a passing car, say, or a barking dog—they spring up like jack-in-the-boxes and open their mouths so wide that they all but disappear behind their straining red maws. As they age, the insides of their mouths darken and are fully black by the time they reach sexual maturity. If you think you might be looking at a juvenile, watch until it opens its mouth.
As soon as I started learning about crows, I began seeing them everywhere. It was almost as if all I needed to do was muse for a moment about some aspect of crow behavior to make one appear. But I had been unsuccessful in my attempts to eavesdrop on the more intimate aspects of their lives, and I certainly haven’t found much that would capture the curiosity of my three-year-old. No crow family has claimed my backyard as its territory, and the nests nearby must be well hidden, because I haven’t spotted any. Whenever I can, I stop to watch crows, but they quickly notice me watching them. Why is this human staring at us? I imagine them thinking, and then they wing away. Usually humans are blind to crows, and when we do pay close attention to them, they’ve learned that it often portends violence.
Nonetheless, I have managed to notice a few things I hadn’t seen before. For example, crows are almost always in pairs. They aren’t always side by side, though; they split and regroup, then split again. When they lose visual contact, they call back and forth until they are reunited. If the crows continue these calls, other crows also come. This gathering call is the classic caw-caw that you probably associate with crows. The scolding that accompanies the mobbing of a raptor has a harsher, screaming tone. Crows are said to have different warning calls for humans and raptors, but I haven’t been able to tune my ear to the difference. They make other sounds too: a clicking trill that sounds like a spoon rattling over a washboard, a bell-like chiming. Swift has recorded a two-toned moan, a rising minor second that sounds just like the famous half step in Jaws: duuh-duh, duuh-duh. No one knows what these sounds mean, and it seems likely to me, given the other similarities between crows and humans, that they mean different things in different places, depending on the local dialect. We know that each flock of crows has its own set of calls forming a sort of song. If an outsider is trying to join a flock and sings the wrong song, the group attacks. But sometimes outsiders stick around long enough to learn the group’s song, which, just as is often the case in human tribes, leads to acceptance.
Most of crow culture is inconspicuous, and they seem to like it that way, but a crow funeral is striking. It’s a sight strange enough to snap normally crow-blind adults out of their spells. When the birds come across a dead body of their own kind, they call in their neighbors. This can go on until a giant congregation is present. Scientists have observed crows placing objects near bodies, and even outlining them with sticks. Haupt has also witnessed what she called a “crow hospice”—a silent gathering around a bird that was dying.
Kaeli Swift is studying these funerals by laying a taxidermied crow on the ground. Each time the pair of crows that controls the territory sees this dead bird, they call their neighbors. Sometimes just a handful show up, Swift said, sometimes forty-five birds have come. They scream, then go quiet, then all scream again. It usually lasts for about twenty minutes. But Swift cautions that what she sees may be different from authentic funerals because she is introducing an unknown bird. “There might be a significant distinction between a stranger bird and a mate of ten years,” she said. For instance, Swift didn’t see any crows holding silent vigils, but there are credible documented observations of crows assembling noiselessly around the body of a compatriot.
Swift has proposed several possible explanations for the behavior. The first is that the crows come to study the cause of death and learn how to avoid it themselves. Avoiding death, along with successful reproduction, is an evolutionary driver powerful enough to create all sorts of behaviors. I have a pet theory that the human fascination with narrative grew from this evolutionary seed: The simplest, most gripping stories tend to be ones about narrowly avoiding death or finding love. So perhaps crows are storing away the lessons death and dying offer so they can pass them on to their chicks.
The second explanation is that these gatherings are less funerals than readings of the will. The death shakes the social hierarchy and the crows assemble to see what it means: Is a mate newly available? Is there territory to be claimed? Perhaps they watch each other and assess who is going to make the first move.
The other possible explanations are emotional rather than rational: The crows gather to grieve or to engage in some kind of spiritual ceremony.
There’s no reason that several of these possibilities can’t all be correct. In fact, it makes perfect sense that emotional and rational explanations would go together, given what we know of neuroscience. The experiences that are stamped most firmly into the memory are the ones accompanied by a powerful limbic system response. Emotion is the glue that makes reason stick.
To many people, roosts of thousands of crows and crow funerals are eerie. When a crow appears in a movie, it’s almost always an ominous symbol. But the influence of crows in our cultural heritage goes far beyond a gloomy omen. We recognize in these birds strange reflections of ourselves, and we gesture to these similarities to make meaning: You can find corvids embedded everywhere in our language. Marzluff and Angell point out that we have crowbars and crow’s-feet, we rave and are ravenous, we “eat crow” and reckon distance “as the crow flies.” These expressions suggest that crows and ravens might even have affected the way we think, because we’ve been using crow metaphors to explain the world for so long that they are now part of the bedrock of collective memory.
I value the cultural associations we’ve made with crows and all the meaning we have built atop them. But it troubles me that we now understand the crow much better as a symbol than as a bird. We’ve used crows to enlighten our own culture, yet ignore their culture.
It’s clear to me that crows do have culture. They pass on lessons to their children and compatriots. They play, and tease, and harbor grudges. They do things that seem illogical, implying deep and intricately reasoned motivations. Raptor mobbings and crow funerals suggest, at the very least, a keen, perhaps overactive, curiosity. At the very most they suggest culture: a collective, perhaps spiritual, affirmation of memory and community.