https://www.newyorker.com/science/elements/the-magic-of-bird-brains Skip to main content The New Yorker * Newsletter Search * The Latest * News * Books & Culture * Fiction & Poetry * Humor & Cartoons * Magazine * Puzzles & Games * Video * Podcasts * Goings On * Shop Open Navigation Menu Find anything you save across the site in your account Close Alert The New Yorker Elements The Magic of Bird Brains Crows are smart enough to pick up trash. Why won't they? By Ben Crair March 5, 2024 * * * * * A group of crows eating french fries from a person. Photograph by Martin Parr / Magnum Save this story Save this story At around 9 A.M. every weekday, a crow caws in the Jardin des Plantes, the oldest botanical garden in Paris. The sound is a warning to every other crow: Frederic Jiguet, a tall ornithologist whose dark hair is graying around the ears, has shown up for work. As Jiguet walks to his office at the French National Museum of Natural History, which is on the garden's grounds, dozens of the black vandals take to the trees and rain abuse on him, as though he were a condemned man. "I think I'm the best friend of French crows," Jiguet told me. "But I am probably the man they hate most." Crows are famous for holding grudges. Their beef with Jiguet started in 2015, when the Paris government hired him to study their movements around the city. Farmers blame crows for crop damage, and hunters shoot hundreds of thousands of the birds each year; in Paris, some district managers wanted permission to cull them for tearing into trash bags and digging up lawns. But Jiguet questioned the wisdom of killing so many crows. "It costs a lot to destroy pests," he remembers thinking. "Can it really be efficient to destroy all these lives?" Outside his office, Jiguet began baiting net traps with kitchen scraps such as raw eggs and bits of chicken. He removed one bird at a time with his bare hands. Then he stuffed the bird into a cloth tube that he had cut from his daughter's leggings, to immobilize the bird while he recorded its weight on a scale. Finally, he strapped a colorful ring, which was labelled with a three-digit number, to the bird's leg. Eventually, Jiguet erected a metal cage the size of a wood shed in the garden, to trap the birds. Crows could fly in, but they couldn't escape until Jiguet let them out. Although some of the birds meekly accepted their fates, some pecked at him furiously when he ringed their legs. Over the years, Jiguet has caught and released more than thirteen hundred crows. He also built a Web site where people could report sightings. These efforts revealed a big shakeup every spring, in which year-old crows flew the coop and looked for new habitats. Some Parisian crows were spotted as far away as the Dutch countryside, but most formed new flocks in the city's green spaces, where there was garbage to eat. Jiguet convinced the city government that there was no point in trying to kill a park's crows: after all, new ones would arrive within a year. "This project definitely changed the view of Parisian politicians on crows," he said. Recently, he published a book about coexisting with crows. The birds were not very appreciative, however. Many of them remembered when Jiguet had caged, manhandled, and banded them. Some had never flown into his trap, but still learned from their peers and joined in the cawing. Crows even recognized him when he showed up for work in a surgical mask, after months of working from home during the pandemic. Jiguet, a lifelong bird-watcher, was learning how it feels when birds watch back. For most of the twentieth century, psychologists dismissed the interior lives of birds because avian brains are smaller and differently structured than those of mammals. But it turns out that bird brains are much denser with neurons and consume less energy, giving crows similar cognitive abilities to large-brained mammals such as great apes, elephants, and whales. John Marzluff, an ecologist in Seattle, once wore a rubber caveman mask while catching and releasing seven crows on his university campus; eighteen years later, crows that weren't alive for the original experiment still caw at the mask. "I really didn't know they were paying that much attention to me," Marzluff told me recently. His study showed that crows not only retain long-term memories but also learn from their peers and pass behaviors from one generation to the next. Other experiments have shown that members of the corvid family, which includes crows, jays, and magpies, can read one another's intentions, plan for the future, and solve puzzles using abstract reasoning and tools. To Jiguet, the ridicule of the crows was a revelation. "I'm just realizing how intelligent they are," he told me. When birds warn one another about individual humans, biologists understand them to have their own culture--defined as a behavioral tradition that a population maintains not through genetic inheritance but through social learning. That struck Jiguet as a cause for celebration, not culling. Wasn't there a better way to relate to clever creatures? Or was cleverness precisely what made them pests? "It's hard to live with animals that are intelligent," Jiguet said. "They can challenge you, and you have to adapt." The nearly fifty species of crow, which include ravens and rooks, emerged long before human civilization. Unlike house sparrows and street pigeons, single species that humans helped to introduce to urban spaces, different crows adapted to different places: American crows to Seattle, house crows to Delhi, large-billed crows to Tokyo, carrion crows to Paris. "All the things we do to make our lives comfortable feed into what they need for habitat and food and shelter," Marzluff told me. Vast flocks of crows can survive on what humans throw away. In 2008, Joshua Klein, a hacker who often wore tight black T-shirts, gave a TED talk about the intelligence of crows. Crows are notorious dumpster divers, but Klein was convinced that a "crow vending machine" could train them to collect trash and other items, like coins. "Let's build something that's mutually beneficial," he said, "and find some way to make a new relationship with these species." First, Klein planned to mix food and coins on the machine's platform. Once crows got used to feeding there, he would remove the food. When hungry crows knocked a coin down a chute, whether by accident or in frustration, a sensor would command the machine to release some food. Klein predicted that a few crows would learn the association between their undirected action and the reward, and start bringing coins of their own accord. Others would then copy the behavior. Millions of people watched Klein's presentation, and in 2008, the New York Times Magazine reported that he had successfully built his machine. But the magazine effectively retracted the story after discovering that he had exaggerated his success. (Klein said that the errors were the result of a misunderstanding.) Crows were certainly intelligent enough to associate coin or trash collection with food rewards, but they had plenty of other places to eat. In the real world, they largely avoided Klein's noisy device. Although Klein failed, his idea caught on. Designers in the Netherlands and an entrepreneur in Sweden tried to build their own machines; a few hobbyists even managed to teach magpies to bring bottle caps to back-yard machines. However, no one managed to disrupt the waste-collection business with a flock of garbage birds. "We didn't have a fully working device that was tested with crows," Ruben van der Vleuten, the Dutch co-founder of a 2017 project to clean up cigarette butts called Crowded Cities, told me. "At the same time, this thing was going viral. We were in so many media outlets." There was social learning going on--but not in crows. Rather, humans seemed to understand that, in the attention economy, clicks and eyeballs were their own rewards. In 2020, another business-school graduate, Jules Mollaret, set out to build a new vending machine for crows, which would exchange trash for bird food. He founded a Marseille-based company, Birds for Change, that aimed to educate people about crows and plastic waste, and he asked Jiguet whether he could experiment in the Jardin des Plantes. "I thought it was a very good opportunity to change people's mind on the species," Jiguet told me. He gave Mollaret permission to install the machine in part of the garden where students grow grapes. I was intrigued by Mollaret's experiment because I often fed crows on my apartment balcony, in Berlin. What started as a pandemic-era distraction became an obsession and a daily routine. I had always thought of animal intelligence as something remote and endangered: the most famous brainy beasts, such as chimpanzees and orcas, lived in distant forests and open oceans, not cities. But, in Berlin, a handful of peanuts was enough to bring animal intelligence to me. The same cognitive skills that help crows recognize threats enabled these birds to recognize me as a source of peanuts--and soon they started waking me up at five in the morning, by knocking on my window with their beaks. When I called Mollaret, he told me that, after almost two years of tinkering with the machine, the crows were nearing the end of their training. They were almost ready to collect bottle caps on their own, he said. And so, on a bright September morning, I arrived at the Jardin des Plantes. (I knew the garden as the place where Ralph Waldo Emerson deepened his interest in natural history; after visiting in 1833, he wrote that "the limits of the possible are enlarged" here.) I found a bench near Mollaret's machine. Crows can be beautiful birds whose black feathers shimmer green and violet, like an aurora in the night sky; in late summer, however, Parisian crows looked ragged from their annual molt. Near my feet, a few nibbled at a discarded peach, but showed no interest in trash collecting. Through my binoculars, I could see that Mollaret was still sprinkling loose food along with the bottle caps on the platform. It seemed that he, too, had overpromised: the crows weren't even close to collecting trash on their own. I soon learned that he was managing the project remotely, from Marseille, with only a part-time helper in Paris. The platform often sat empty over weekends, giving the crows no reason to think of the machine as a reliable source of food. ("I don't think it's working," Jiguet confessed to me later.) Mollaret seemed to think that, because crows are smart, their behavior should be predictable and programmable--even if his own behavior wasn't. He was treating ecology like a subset of mechanics, as though the crows themselves could be turned into cogs in a machine. Klein, the inventor of the "crow vending machine," has called himself a "passionate hacker of all things," but, the more I watched crows in the Jardin des Plantes, the more I wondered who was hacking whom. I saw crows fish McDonald's bags out of trash cans and follow strollers and toddlers, knowing that children were more likely to drop crumbs. They visited the garden's menagerie, one of the world's oldest zoos, to raid food from the llama and rhea enclosures. Evolution had empowered crows to expose the weak spots in our designs, and I found myself admiring their mischief as a rebellion against our hubris. "Crows and ravens have co-evolved with us since the time of Neanderthals, and yet we've never domesticated them," Marzluff, the Seattle ecologist, told me. The real mark of crow genius may be its ability to maintain independence in spaces that humans think of as their own. A few years ago, Jiguet's children began playing Pokemon Go, the smartphone game in which users catch virtual animals as they wander through real-life spaces. He tried, unsuccessfully, to interest his kids in real animals. But, in the end, he wound up downloading the game himself. He started to chase Pokemon through the Jardin des Plantes, which was one of the best places in Paris to catch them. Fittingly, many of the garden's manicured paths were named after famous nineteenth-century naturalists, some of whom collected actual animals as though they were Pokemon, filling the natural-history museum's cabinets with curious creatures. One day, in 2017, Jiguet met a woman named Marie-Lan Tay Pamart who was also playing Pokemon Go in the Jardin des Plantes. Capturing virtual animals, which did not heckle or bite, was a welcome respite from trapping cranky crows--but there were several birds in Jiguet's cage that day, and he invited Tay Pamart to help him attach rings to their legs. Tay Pamart was startled to go from chasing imaginary creatures on her phone to suddenly holding a live crow in her hands. "Its heart was pumping because it was so stressed out," Tay Pamart told me. She felt as nervous as the bird. Tay Pamart started to recognize the garden's crows by the colors and numbers of their rings. "It was almost like Crow Go," she recalled. "I was interested in getting as many rings as it was possible for me to get." Diane Dabir-Moghaddam, who studies beetles at the museum and watches crows in her free time, told me that "because you can see the rings, you can begin to remember them, have a relationship with them, and know how they behave." Here was a third way to connect with crows, beyond culling or training them: simply getting to know them in the spaces we share. Even Jiguet, who normally concerns himself with population trends, started to see crows as individuals with distinct personalities. "There are a few birds that have special histories," he told me. Jiguet banded one such crow, Green 279, after he fell from a nest and grew up in an animal-rescue center; he was the only rescued crow to survive after being released into the garden. Green 279, who was named for the color and number on his ring, willingly entered Jiguet's cage to eat, having learned that he would always be released again. But he also seemed to hate Jiguet. "This is the most aggressive bird to my fingers," he told me. Green 279 was able to distinguish friend from foe. When I sat with Tay Pamart and Dabir-Moghaddam on a bench in the garden, he soon turned up. The women teasingly called him Globe-Trotter, because he had never been seen outside the gardens. "He takes food from my fingers," Tay Pamart told me. "He has come onto my shoulder," Dabir-Moghaddam added. Green 279 watched us closely. "He wants cat kibble," Tay Pamart explained. Dabir-Moghaddam apologized to him for bringing only peanuts. Watching them, I thought about a pair of crows that I feed from my Berlin balcony. At first, to test their wits, I set up small puzzles, which struck me as the obvious way to interact with smart animals. But, with time, I realized that the crows were solving a larger puzzle than any of my contraptions. The female figured out that, if she fluffed up her feathers, or just patiently stared me down, I would come to the balcony with handfuls of peanuts. I grew to love her not because I could bend her behavior but because she was capable of bending mine. Loren Eiseley, the twentieth-century anthropologist, once wrote about a crow that nearly crashed into his head on a foggy day, and subsequently cawed at him every day as he walked to the train station. He described what they shared as "a viewpoint in common." Hundreds of millions of years of evolution separate humans from birds, but "our worlds had interpenetrated," Eiseley wrote. That day in Paris, the Jardin des Plantes felt like a borderland where worlds were colliding. As I walked through the garden with Tay Pamart and Dabir-Moghaddam, Green 279 and his companions followed us. Near a pond, we scattered some peanuts, but many of the crows lost interest: they had spotted a young girl who was eating brioche. Then we came upon two other women who were also tossing peanuts. "There's quite a community of people who are interested in the crows," Tay Pamart told me. Green 279 had now extracted so many peanuts from his human admirers that he didn't want to eat anymore. Instead, he began caching peanuts under some fallen leaves, so he could return to them later. We were the crow vending machine, I realized, and the birds had mastered the art of manipulating us for rewards. Spilled trash seemed like a small price to pay for proximity to such clever minds. More Science and Technology * Can we stop runaway A.I.? * Saving the climate will depend on blue-collar workers. Can we train enough of them before time runs out? * There are ways of controlling A.I.--but first we need to stop mythologizing it. * A security camera for the entire planet. * What's the point of reading writing by humans? * A heat shield for the most important ice on Earth. * The climate solutions we can't live without. Sign up for our daily newsletter to receive the best stories from The New Yorker. Ben Crair is a journalist based in Berlin. More:CrowsOrnithologistsAnimal Behavior Daily Our flagship newsletter highlights the best of The New Yorker, including top stories, fiction, humor, and podcasts. E-mail address [ ] Sign up By signing up, you agree to our User Agreement and Privacy Policy & Cookie Statement. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. 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