Bay Nature magazineWinter 2019

Farming and Ranching

Crows are Wicked Smart

Should an animal's intelligence change the way we treat it?

December 28, 2018

In the spring of 1989, Kevin McGowan put a white plastic band around the leg of a nestling American crow in Ithaca, New York. An ornithologist at Cornell University, he hoped to learn more about American crows—the ones you likely see daily, hereafter labeled as crows. 

Given their ubiquity, it was striking how little was known about their social lives. Why did young crows often forgo raising families of their own and instead help their parents raise new broods? Did crows hold territories? How long did families stay together? Did urban and rural crows have different habits? Basic questions were shrouded in uncertainty. 

The search for answers would ultimately lead McGowan and colleagues to tag some 3,000 birds. He’s tracked their movements and associations and fates—and though his research didn’t focus on crow communication, he couldn’t help but pay attention. Gradually McGowan started to recognize distinct calls. He began, he thought, to understand what the birds were saying. 

“They don’t have a lot of nuance. They talk about the basics of day-to-day life,” McGowan says. “The first thing they do when they get up is say, ‘I’m alive. I’m still here.’ They talk about food, about predators, about where they are.” They probably say more, but translation isn’t easy. Subtle changes in timing and intonation seem to alter the meanings of their calls, which McGowan analogizes to tonal languages like Chinese. It’s hard for his English-native ears to follow. 

Yet even these rough translations are, by their mere existence, remarkable. Language is often said to be what “makes us human,” what differentiates humans from animals. Crows may not satisfy all the conditions that linguists attach to human language—there’s not yet evidence, for example, that they rearrange the order of their calls to create new meanings—but they have something like a language, a system of communication that falls on a spectrum with our own. This fact challenges those assumptions about human uniqueness. 

Moreover, study after study has described the rich cognition of corvids, a family that includes crows as well as ravens, jays, and nutcrackers. So intelligent are corvids that some scientists call them “feathered apes.” They solve puzzles that stump human children, plan for the future, make tools, remember birds—and humans—they encountered years earlier, and on and on. They’re stars of the last quarter-century’s surging study of animal minds; insights into their and other animals’ cognition have helped sweep away a widely prevalent but narrow-minded view of animals as mechanical and unintelligent, instead revealing a world populated by thinking, feeling nonhuman minds. 

This new scientific awareness complicates our relationship with these creatures. It gives weight to arguments for treating them more considerately—a mostly noncontroversial proposition when it comes to animals that resemble us, such as chimpanzees, or charismatic species like orcas and elephants, or the pets with which we share homes. But crows and ravens, whose Bay Area numbers have increased dramatically in the last few decades, are a harder sell. They’re not obviously cute or magnificent. People tend not to think much about them at all. When we do, we often see them as noisy pests. Perhaps that should change.  

For as long as we’ve recorded history,  people have considered animals intelligent; the view of them as dumb was an outlier, emerging from Greek philosophy, becoming reified in Christianity and flourishing with the Enlightenment and modern colonialism. Yet even Charles Darwin didn’t buy it. To him, animal intelligence was simple evolutionary fact: just as humans shared common physical traits with other animals, so too we shared mental capacities. 

An overreliance on anecdote hurt supporters of this view, though. Darwin’s own protégé, George Romanes, infamously presented secondhand stories of wounded monkeys shaming hunters by extending their bloody paws as evidence of their mental abilities. The backlash was fierce. Behaviorism and its characterization of animals as unthinking stimulus machines emerged and dominated academia for most of the 20th century. Only in the late 1970s did a few scientists begin to challenge the behaviorist dogma, and this time they brought rigorous experimental methods to the debate. 

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Corvids, being amenable to laboratory life, and with a rich history of anecdotal observations suggesting their intelligence, made for ideal study subjects. One well-known series of experiments is modeled on Aesop’s fable about a thirsty crow dropping stones into a pitcher of water until its level rose and the crow could drink; in the experiments, European rooks and New Caledonian crows drop stones into a tube of water in order to reach a floating snack. (American crows haven’t yet taken this test—but it’s fair to extrapolate that their minds work this way, too.) Some scientists interpret this as evidence of intuition, cause-and-effect reasoning, and a basic grasp of physics, though others argue that’s just trial-and-error learning. The explanations are not mutually exclusive. The birds try things out and learn from what happens. It’s not so different from what we do. 

Smarts are not restricted to physical problem-solving. Just as important, perhaps more so, is social intelligence. Crows are extremely social and must master rules of engagement, customs, communication. They are born with a vocabulary of several dozen calls, McGowan says, but need to learn what each one means. Often while watching his crows he’ll hear a juvenile reciting the entire repertoire, as if practicing. 

Slight variations exist between calls from different regions—accents, if you will—but the meanings remain constant. The calls don’t exhibit the heavy cultural influences found in certain other birds, such as monk parakeets, whose keep-in-touch contact calls are region-specific. But that doesn’t mean crows and ravens lack culture. Quite the opposite. 

McGowan first observed crows opening plastic garbage bags in the late 1980s. The ability spread as other crows copied the innovators. Scientists know the birds can exchange information directly, which could accelerate the spread of useful knowledge. When researchers in the lab of John Marzluff, a corvid cognition expert at the University of Washington, trapped crows and then released them, it wasn’t just the captured birds that later accosted the researchers; so did crows they hadn’t trapped. News of the untrustworthy humans had spread.

These flows of information underlie cultural evolution that, rather than biological adaptations, may have helped swell urban corvid populations far beyond their historical numbers—a trend often explained purely in terms of garbage-eating. But one of the most important cultural adaptations, McGowan says, involves how crows and ravens regard humans. After being ruthlessly exterminated for much of America’s history, they’re now mostly ignored, and they act accordingly. They’re not just learning how to better exploit human resources; they’re learning about the character of modern Americans.

crow
American crow. (Photo by Joel Sartore, NG Image Collection)

Like our own societies, those of crows and ravens are fission-fusion. Groups form and split and come together in new configurations across time and space. The lifestyle offers many potential benefits—safety in numbers, shared knowledge of food sources, cooperation to obtain it—and also disease, aggression, and competition.

The need to manage social complexity has shaped many facets of crow and raven cognition, including extraordinary powers of recall. Ethologists Thomas Bugnyar and Markus Boeckle of the University of Vienna and the University of Cambridge, respectively, tested raven memories by playing them recordings of cage-mates they’d last encountered several years ago; the ravens reacted differently to voices they knew than to recordings of strangers. They seemed to remember their old friends.

The results testified to the importance of social memory, and little wonder. Knowing the identities and qualities of other individuals—whether someone is a reliable source of information, whether they’re even-tempered or quick to fight, whether they owe you a favor or vice versa—will help one survive. Social bonds can be quite powerful: Melanie Piazza, director of animal care at the WildCare wildlife hospital in San Rafael, tells of how juvenile crows sometimes feed their cage-mates as if practicing to be parents.

Scientists have also described how ravens, offered a choice between a small snack now and a larger treat later, will delay gratification—an exercise in self-control and future-awareness that’s considered a developmental milestone in humans. In a variation on that experiment, ravens will also forgo the snack in exchange for a tool they can later use to open a box of food. The experiment suggests an ability to make plans, a profound faculty whose existence argues against the common trope that animals live—blessedly or cursedly, depending on your view—in the eternal present. Ravens, and quite likely crows, can live outside the moment. 

Notably absent from this research is a sense of the birds’ emotional lives. The bias is common to animal intelligence studies as a whole and is partly rooted in the field’s unfortunate historical legacy: scientists who challenged behaviorist dogma favored experiments whose results were as straightforward as possible. Cognitive intelligence—memory, reasoning, problem-solving—was easier to empiricize than were emotions, which are plenty slippery even in humans. 

That has changed somewhat over time. Innovations in experimental methods have encouraged studies of animal emotions. Tests originally designed for very young children, whose willingness to gamble on uncertain outcomes reflects their emotional state, have been adapted to read the moods of pigs and sheep and even bees. And while crows and ravens have yet to take these tests, several lines of evidence point to the possible richness of their emotional lives.

Crows and ravens possess the neurological chemicals and structures that, as scientists know from our own brains and other mammals’ , are integral to emotion. It’s not a one-to-one comparison—we have oxytocin and they have mesotocin; their prefrontal cortex is shaped differently than our own—but it’s similar enough. “These mechanisms are highly conserved,” says Claudia Wascher, a biologist at Anglia Ruskin University who specializes in avian social cognition. Emotions are just mechanisms for shaping behavior. Pain, pleasure, fear, anticipation, happiness, sadness: they’re a steering system. Evolutionary theory predicts they should be widespread, and complex social relations like those seen in corvids exert pressures that ought to select for their expression. 

One of Wascher’s experiments involved greylag geese whose heart rates dropped when family members were near. Their relatives’ presence calmed them. That effect hasn’t yet been tested in crows and ravens, Wascher says, but likely holds true of them too. And monogamy, the institution at the center of crow and raven life history, should be an especially fertile ground for emotions: how better to unite two individuals through a lifetime of nest-building and food-gathering and chick-raising than with feelings? 

McGowan recounts the story of a male crow he named AP who chose between females vying for his attention; the one he spurned later became a very successful breeder, but the broods he and his partner raised failed, year after year. “They were together for eight years,” McGowan says. “They didn’t do very well with raising kids, but they were a good couple. They were together pretty much every day they were paired.”

With characteristic caution, McGowan adds that “one does assume that long-term pair bonds have some sort of emotion.” John Marzluff goes further. “When you talk about love or grief,” he says, “frankly, I think that some of those emotions are part of their world.” 

 Whether their loves and griefs are the same as ours, he says, is impossible to say. Maybe it actually feels like something else to them. Still, those behaviors point toward emotional richness. Experiences don’t need to be identical to ours to be powerful. When AP’s mate died, he was 18 years old. Not long after, he lost his territory and spent his final year at a local compost facility. Such outcomes are usually explained in utilitarian terms: a younger, stronger individual bests a rival weakened by age. But, says McGowan, “you wonder what happens when you lose a mate like that after that much time, when you’re getting old. Do you give up? Do you think, ‘She died. Why do I even want to fight for this territory anymore?’” 

During a visit to San Francisco last spring I stayed near Ocean Beach, where crows and ravens were by far the most populous animals. Several always seemed to be visible: a pair of ravens driving a red-tailed hawk from their rooftop perch. A crow flying down a sidewalk carrying what looked like a strip of raw steak. Two more ravens atop a garbage can, seeming to meet my gaze.

Months later, I can still picture them. Not because the encounters were especially unique; on the contrary, they were entirely ordinary. But as Boria Sax, a scholar of human-animal relations, wrote in Crow, corvids are simultaneously ubiquitous and mysterious. “There always seems to be something important going on, some domestic drama that is being acted out,” writes Sax.  

If contemporary science doesn’t fully dispel those mysteries, it certainly helps make it possible to relate to corvids anew. We can hear their caws as conversations rather than cacophonies; rather than seeing them as anonymous, we can appreciate each as an individual living his or her own life in the first person.

As of now, though, this perspective is not widespread. “We have two camps,” says WildCare’s Piazza. “There are the people who absolutely love crows and ravens, who appreciate their intelligence and everything they have to offer. And then folks on the other side, who see them as a nuisance and don’t want them around.”

Marzluff says the general public tends to be more interested in corvids than are birders. Bob Lewis, a Berkeley resident and a former Golden Gate Audubon board member who helps coordinate the Oakland Christmas Bird Count, echoes the point. For the last five years, he’s taught a birding class at the California Academy of Sciences, and each year he asks students to write a short paper on some avian subject. Of the 100 or so he’s received so far, none have involved crows or ravens. 

Of more interest to bird enthusiasts and conservationists is how corvids’ growing numbers affect other species. In the late 1970s, the Oakland Christmas Bird Count counted just a handful of ravens, and well into the 1980s the counters tabulated just a few dozen crows. Last year, they spotted 283 ravens and 1,215 crows. The trend worries some people: all those corvids need to eat. “There have been concerns about declines of songbirds and waterbirds,” says Yiwei Wang, executive director of the San Francisco Bay Bird Observatory. “I wouldn’t say that crows and ravens are the main cause, but they are one of the causes.” 

While research suggests that corvids, even in large numbers, often have negligible impacts on other animals, they can be problematic for some rare species. In the Bay Area, these include western snowy plovers, Ridgway’s rails, California least terns, and salt marsh harvest mice. 

For these species’ sake, crows and ravens are killed at sites in the Don Edwards San Francisco Bay National Wildlife Refuge, the Salinas River National Wildlife Refuge, the Alameda National Wildlife Refuge, and the Eden Landing Ecological Reserve. Among those programs, snowy plovers—which, when federally listed as endangered in 1993, had dwindled to a mere 1,500 individuals—are the most high-profile. “It’s not that we see crows and ravens as the enemy. But if your goal is to protect snowy plovers, then we have to control the things that eat their babies and their eggs,” says Wang. “Conservation is a value-based science, and the value here is to protect species from going extinct.”

Not long ago, exterminating corvids for the sake of endangered species would have provoked few qualms. In the last few years, though, a  number of conservationists have voiced discomfort about killing some animals for the sake of others. They urge “compassionate conservation,” and they apply ethical frameworks refined in animal welfare circles to conservation decisions that typically focus on populations and species. Animals think and feel, the argument goes, so every individual life deserves respect. Protecting rare animals isn’t a moral free pass for killing common ones. “It’s about emotions, sentience, feelings, suffering,” says William Lynn, an ethicist at the Marsh Institute at Clark University. “It’s about refraining from [causing] suffering.” 

When I put human characteristics onto a ‘varmint’ bird, people seem to find a different value. They’re often embarrassed or even ashamed about killing a crow I know.

Proponents of lethal control say it’s perverse to allow a few animals’ well-being to supersede the continued existence of an entire species. But compassionate conservationists retort that killing offers an illusory hope. It distracts from root-level causes of extinction, which are almost always human in origin and inconvenient to confront. In the Bay Area, for example, crows and ravens are not to blame for how a precious few plovers are pushed onto tiny mudflats beside an oversimplified, garbage-rich landscape that attracts corvids as well.

Some compassionate conservationists concede that killing is justifiable—but only in exceptional cases and if certain conditions are met. People must be absolutely certain that the animals killed are an existential threat; they can’t be scapegoated, as with a raven-killing program suspended earlier this year in Scotland for lack of evidence that they actually harmed shorebirds. Every nonlethal alternative must be exhausted. “You have to acknowledge that they’re the equivalent of a nonhuman person,” Lynn insists. “If folks haven’t thought through the issue of their intrinsic value, that’s a real problem for me.”

In the Bay Area, such consideration happens to some degree. Eric Covington, a district supervisor with USDA APHIS Wildlife Services, the federal program that handles predator control at Don Edwards and the other sites, says that only individuals that have been seen preying on threatened animals are targeted. Before the guns come out, their presence is discouraged with loud noises, effigies—literal scarecrows—and the removal of perches. Conservationists have also worked with landfill companies to reduce garbage access. Habitat restoration is underway at key wetland sites in the region. 

Still, the deeper problems won’t realistically be fixed anytime soon. Streetside and parking-lot trash remains a vast, easy source of food. Landscape fragmentation is here to stay. The foreseeable future will probably involve killing crows and ravens to help more precarious species. If killing is necessary, though, perhaps we can acknowledge it as tragic and offer a kind of compensation. For every unfortunate crow and raven killed for the benefit of other species, I would argue, conservationists might pay for the care of an injured bird elsewhere. 

Piazza says that WildCare treats some 160 crows and 10 ravens each year. They’ve been shot with air guns or injured when people cut down trees; they get tangled in discarded fishing line, hit by cars —sometimes intentionally—while eating roadkill, or poisoned. Whatever you think about conservation killing, the suffering of these birds is senseless, and the responsibility is ours. 

As for McGowan, he’s pessimistic that better understanding corvid intelligence will lead to better treatment, yet his own experience suggests it’s possible. 

When people call him after shooting one of the crows he tracks—each identification tag has McGowan’s phone number—“I thank them for contacting me,” he says. “Then I tell them something about the crow they shot, how old it was and how it was helping raise a brood of siblings this year. When I put human characteristics onto a ‘varmint’ bird, people seem to find a different value. They’re often embarrassed or even ashamed about killing a crow I know.”

About the Author

Brandon Keim is a freelance nature journalist and author of The Eye of the Sandpiper: Stories of the Living World. Now living in Bangor, Maine, he resided for a while in Bethesda, Maryland, where from an upper-story apartment window he often saw the neighborhood crows chase red-tailed and red-shouldered hawks — but rather than injure the outmaneuvered raptors, the crows only pulled at their quarry’s feathers, as if counting coup. @9brandon

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