Japanese Carrion crows have found a clever way to crack hard walnuts, turning passing cars into their own - The Times of India

Wren: Welcome to Bird Brains — the show where being called a bird brain is the highest compliment I can give you. I'm Wren, ornithologist, crow obsessive, and your guide through the genuinely astonishing inner lives of corvids — that's crows, ravens, magpies, and jays. Huge thanks to our sponsors today: Ada, who helps businesses actually integrate A I into their workflows in ways that work; Ago Consulting — that's "Ahh-Go" — silicon development experts covering everything from A I to SoC; and Zen Semiconductor, an umbrella company with a whole portfolio of businesses across the silicon industry. We are so glad to have them along for the ride. Today on the show — Japanese crows turning rush-hour traffic into a walnut-cracking machine, the science behind whether crows can actually understand what another bird is thinking, and a story about crows and people that is going to make you want to leave peanuts on your windowsill. Let's get into it. Wren: Okay, thread one. Corvid cleverness. And I want to start with a story that I genuinely love telling because every time I do, someone in the room says — wait, they do what? So here we go. Sendai, Japan. Busy intersection. Cars rolling through, stopping at red lights, rolling through again. Standard urban chaos. And perched up on the power lines above it all — Japanese carrion crows. Watching. Waiting. Thinking. Because these crows have figured out something remarkable. Walnuts are delicious. Walnut shells are, unfortunately, very hard. Too hard for a crow beak to crack. So what do you do when you have a problem that your body can't solve on its own? You use a tool. Except these crows didn't pick up a rock or a stick. They outsourced the cracking to a forty-mile-an-hour Toyota. Wren: Here's what they do. A crow picks up a walnut — sometimes they'll carry it quite a distance — and places it carefully in the road. Not just anywhere in the road. In the path of oncoming traffic. Then they fly back up and wait. A car rolls over it, crack. But here's where it gets even better, because this is the part that really separates clever from extraordinary. The crows don't just dive down immediately after the car passes. They wait. They wait for the red light. When the light turns red, traffic stops, and the crow walks calmly into the crosswalk — the crosswalk! — picks up the walnut meat, and flies off. They are using pedestrian crossing signals. They have incorporated human infrastructure into their foraging strategy in a way that keeps them safe while maximizing their reward. Wren: This behavior was first documented and studied by Yoshiaki Nihei in the 1990s, and researchers have observed it at multiple sites since. What's important here isn't just the wow factor, though the wow factor is enormous. It's what this tells us about crow cognition. To do this, a crow has to understand cause and effect — car goes over walnut, walnut breaks. It has to understand sequencing — place walnut, retreat, wait for light, then retrieve. And it has to understand that the red light means the cars will stop, which means it's safe to go in. That's not instinct. That's not luck. That is multi-step planning with an understanding of a human-built system. And these crows didn't read the traffic manual. They figured it out by watching. By paying attention to the world around them and asking — how does this work, and how can I use it? Wren: What I also love about this story is how it spreads. Because corvid researchers have noted that these behaviors aren't just individual discoveries — younger crows learn by watching older crows. This is cultural transmission. A walnut-cracking technique passed from one generation to the next, not through genes, but through observation and imitation. That is, depending on how you define the word, a form of culture. In birds. Standing at a crosswalk. Wren: Alright, thread two. How their minds actually work. Because once you've seen what crows can do, the obvious question is — okay, but how? How does a brain the size of a walnut — and yes, I am aware of the irony — produce that level of sophisticated thinking? And this is where the neuroscience gets genuinely exciting. Wren: For a long time, the assumption in science was that intelligence required a big, wrinkled neocortex — the outer layer of the brain that in mammals handles complex thought, planning, decision-making. Crows don't have a neocortex. Birds don't. So for decades, the working assumption was that they simply couldn't be doing the kinds of things mammals do when they think. And then researchers started actually testing crows. And the crows kept passing tests they weren't supposed to be able to pass. Wren: What birds do have is a region called the pallium, and within that, a structure called the nidopallium caudolaterale — which I promise is the last Latin I'll throw at you today — and this region appears to function analogously to the mammalian prefrontal cortex. It's involved in planning, impulse control, working memory, flexible decision-making. So corvids essentially evolved a different architectural solution to the same cognitive problem. Different building, same output. Which is a beautiful example of convergent evolution — nature finding the same answer through different paths. Wren: Now. One of the most fascinating recent areas of research involves something called Theory of Mind. And this is huge. Theory of Mind is the ability to understand that other individuals have their own mental states — their own knowledge, beliefs, desires — that may be different from yours. It's the cognitive leap that lets you think: I know where I hid my food, but that other crow over there saw me hide it, so he knows too, and I need to do something about that. For a long time, Theory of Mind was considered a uniquely human ability. Then great apes showed some evidence of it. And then researchers started looking at crows. Wren: Studies — including work published in peer-reviewed journals examining corvid caching behavior — have found that crows who were watched while hiding food will go back and re-hide that food when they think they're being observed by a competitor. But here's the nuance. They only do this re-caching if they themselves have previously stolen food from another bird. Crows who have never stolen don't seem to show the same level of suspicion about being watched. The inference researchers make is striking: the crow is projecting its own experience of theft onto the other bird. It's essentially thinking — I know what I would do in your position, because I've been in your position. That is a form of mental perspective-taking. In a crow. And that finding has been replicated and extended by multiple research groups, including work out of Cambridge. Wren: There's also the mirror test question — magpies, our corvid cousins, are one of the only non-mammal species to have passed versions of the mirror self-recognition test, suggesting some form of self-awareness. And then there's episodic-like memory — the ability to remember not just what was cached, but where and when. Jays have been shown to remember the specific location of hundreds of cached food items and to account for the perishability of different foods when deciding which cache to visit first. They're not just remembering. They're mentally time-travelling. Wren: So when we ask how a crow's mind works — the honest answer is: in ways we are still figuring out, and in ways that keep surprising us. Every time we design a test we think will stump them, there's a very real chance a crow somewhere is going to prove us wrong and look mildly smug about it. Wren: Okay, thread three. My favorite thread. Crows and people. Because beyond the labs and the experiments, there are these remarkable documented stories of corvids and humans forming genuine, ongoing relationships. And one of the most well-known and beautifully documented examples is the story of Gabi Mann, a young girl in Seattle, Washington. Wren: Gabi started feeding crows near her home when she was around four years old — accidentally at first, just dropping food. But as she got older, she and her family started deliberately putting out food for the local crows every day. Water, peanuts, dog food. And the crows started to notice. They started showing up reliably, recognizing Gabi and her mother, even alerting them when they forgot to put out the food on time. That relationship was already remarkable. But then the crows started leaving things behind. In the dish where the food went — small objects. A piece of foam. A broken light bulb. A miniature silver ball. A blue button. A small piece of metal with the word "best" printed on it. Over several years, Gabi collected dozens of these objects, which her family catalogued carefully with notes about where each one appeared and when. Wren: This story was documented by the BBC, and researchers who study corvid behavior have weighed in on what might be happening. Crows cache objects as well as food — they store things of interest. And they have been observed in other contexts apparently reciprocating when they have a positive social relationship with a human. Whether this is intentional gift-giving in the way we understand gifts — "I am choosing to give this to you as an expression of our relationship" — that's genuinely debated among scientists. But what is documented is the pattern: regular provisioning by humans, followed by regular deposition of objects by the crows, directed specifically at those humans. Whatever you want to call that, it is a reciprocal relationship. It is the crows responding to being cared for. Wren: And what strikes me about this is the face recognition piece that underpins it. Because the crows weren't leaving gifts for everyone. They were leaving them for Gabi and her mother specifically. Research has established — through clever mask experiments at the University of Washington by researcher John Marzluff and colleagues — that American crows can recognize and remember individual human faces. In those experiments, researchers wore specific masks while trapping and banding crows. Years later, crows on that campus would scold, dive-bomb, and recruit other crows to mob the people wearing those masks — even when the masks were worn by entirely different people, or worn upside down. The crows passed information about the dangerous face to other crows who had never even been trapped. The grudge — and the warning — spread through the population. Wren: So it works both ways. Crows remember the people who threaten them. And they remember the people who feed them, who show up reliably, who treat them well. They are paying attention to us in ways most people never imagine. You might walk past the same crow every single morning on your commute and think — it's a crow, it doesn't see me. But it sees you. It probably knows your face. It almost certainly has an opinion about you. And that idea — that we are being observed and assessed and remembered by the birds around us — I find that completely wonderful. Wren: Crows are not background. They are participants. They are watching the same world we walk through, and drawing their own conclusions. And if you have ever wondered what they think of us, the honest answer is: it depends on what you've done for them lately. Wren: So here's what I want to leave you with today. Intelligence is not one thing. It didn't evolve once, in one place, in one shape. It emerged independently — in mammals, in birds, in octopuses, in creatures that solved the same problems of survival with completely different neural architectures. And when we look at corvids — at a crow waiting for a red light, at a jay planning next winter's pantry, at a magpie recognizing its own reflection, at a raven who remembers your face years later — we are seeing what intelligence looks like when it grows wings. And honestly? It looks pretty spectacular. Bird Brains is brought to you by Ada, Ago Consulting, and Zen Semiconductor — thank you so much for supporting the show. If today's episode surprised you, delighted you, or made you want to go leave peanuts out for your neighborhood crows — please subscribe, leave a review, and share it with someone who still uses "bird brain" as an insult. We can fix that together. And check the link in show notes for references to everything we covered today. I'm Wren. Stay curious out there.