Crows vs. Ravens: A Numbers Game Study Finds Crow Mobbing Is a Key Strategy Against a Bigger Bird | Newswise - Newswise

Wren: Welcome to Bird Brains — the show where we take the ultimate insult and turn it into the ultimate compliment. I'm Wren, ornithologist, science communicator, and someone who has spent way too many mornings staring up at crows and thinking, "You know what? You're smarter than half the people in my inbox." Today we've got a genuinely fantastic episode — we're talking mob tactics, the science of crow cognition straight from Sorbonne University, and a wild story about crows being recruited to clean up cigarette butts in Sweden. Yes, really. Huge thanks to our sponsors making this show possible: 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. Alright, bird people — let's get into it. Wren: So let's start with something that I find genuinely thrilling, and that is corvid cleverness in action — not in a lab, not in a textbook, but out in the wild, playing out in real time in the skies above our heads. And today's story is about a behaviour called mobbing. Now if you've ever seen a crow dive-bomb a hawk, you already know what I'm talking about. But a study that's been making the rounds recently digs into the specific relationship between crows and ravens — and it is fascinating, because these are not friendly neighbours. These are rivals. Ravens are bigger. Ravens are bolder. And if a raven finds a crow's food cache, or wanders too close to a nest, that crow has a problem. So what do crows do? They don't fight one-on-one. That would be foolish. Instead, they recruit. They call in the crew. Mobbing — where multiple crows harass a single larger bird together — turns out to be a genuinely strategic behaviour, not just chaos. The research found that crows essentially run a numbers game. The more crows that show up to mob a raven, the more effective the harassment, and the more likely the raven is to just... leave. Which sounds obvious, maybe, but here's what makes it interesting: crows appear to calibrate their response based on the threat level. They're not just reacting emotionally — they're assessing. How big is this bird? How close is it to something we care about? Do I need two friends or ten? That kind of flexible, situation-dependent group coordination is not something you see in animals operating purely on instinct. It requires communication. It requires social awareness — knowing who's in your group, who will respond, who you can count on. And crows absolutely have that. They live in complex social structures. They remember individuals — both within their species and outside of it, including us, by the way, but we'll get to that. What I love about mobbing as a behaviour is that it flips the power dynamic entirely. A raven can absolutely win a one-on-one confrontation with a crow. But five crows? Ten crows? Suddenly the calculus changes. The raven has to weigh the energy cost of sticking around against whatever reward it was after. And more often than not, the raven decides it's not worth it. The crows figured out leverage. They figured out collective action. And they've been using it for thousands of years before humans invented the concept of a union. Wren: Okay, so we've seen crows working together in the field — now let's talk about what's actually going on inside that little feathered skull, because this is where it gets genuinely mind-bending. There's been some really wonderful work coming out of Sorbonne University recently asking, simply: are crows really that smart? And the answer, spoiler, is yes — but the *why* is what's interesting. Because here's the thing that trips people up. Bird brains are small. Crows don't have a neocortex — the layered brain structure that we associate with higher thinking in mammals. For a long time, scientists basically assumed that without a neocortex, you couldn't have complex cognition. Case closed. Except — crows kept doing things that complex cognition is supposed to produce. They were solving multi-step problems. They were planning ahead. They were recognising human faces and holding grudges against specific people who'd wronged them. And scientists had to go back and rethink the whole framework. What we now understand is that corvid brains have a region called the pallium — and within that, a structure called the nidopallium caudolaterale — which functions in remarkably similar ways to the mammalian prefrontal cortex. It's a case of convergent evolution. Two completely different brain architectures arriving at similar cognitive destinations through completely different routes. And the density of neurons in corvid forebrains is extraordinary — comparable in many ways to primates. So when a crow is standing there, tilting its head at you, looking almost uncomfortably thoughtful — it kind of is. Now, one of my favourite illustrations of this comes from experiments on episodic-like memory in western scrub jays — now called California scrub jays. These birds cache food. They hide it for later. But here's the twist — they also steal from each other. And researchers found that jays who had stolen food themselves were more likely to re-hide their own caches when they thought another jay had been watching them. Think about what that requires. It requires the jay to understand that the other bird has knowledge — that it *saw* something. It requires a kind of perspective-taking, an awareness that other minds exist and contain information. That's theory of mind territory. In a bird. It also requires something like planning — not just for next hour, but anticipating a future social scenario and acting to prevent a bad outcome. That is not bird-brained in the old sense of the phrase. That is exactly the kind of thinking we've always assumed was uniquely human. And the crows — and jays, and ravens, and magpies — have been quietly demonstrating otherwise for quite some time. Wren: And now, my favourite part of every episode — the corvid-and-people story. Because these birds don't just tolerate us. They engage with us. They study us. Sometimes they absolutely work us. And today's story starts in Sweden, with an idea that, honestly, I wish had worked out differently. A company called Corvid Cleaning — yes, that's the actual name — had a genuinely viral concept: train crows to pick up cigarette butts in exchange for food rewards. And if you're thinking, "Wait, can you even do that?" — yes, actually, you can, because crows can absolutely learn to associate picking up objects with receiving a food reward. The cognitive machinery is there. Crows in various research settings have been trained to drop tokens into slots, to retrieve specific items on command — they're remarkably good at learning exchange systems. The idea was elegant. Cigarette butts are one of the most common forms of litter on the planet. They're toxic, they're everywhere, and we humans are apparently not great at picking them up ourselves. Why not recruit a species that's abundant, urban-adapted, and demonstrably capable of learning complex tasks? The program got enormous media attention. People loved it. And then it collapsed. Now, the reasons are a bit complicated — there were concerns raised about the welfare of the birds, questions about whether the training setup was rigorous enough, and practical challenges with scaling. And honestly, the story of its collapse is almost as interesting as the story of its concept, because it runs straight into questions we're still figuring out: what do we owe animals when we recruit them for our problems? Is it ethical to train wild corvids to clean up human messes? The crows didn't make the cigarette butts. We did. But here's what I want you to take away from this story, even though the company folded: the fact that it was even attempted — that it was even plausible — tells you something profound about where crows sit in the animal kingdom. Nobody is out here trying to train sparrows to pick up litter. Nobody's pitching a "pigeon cleaning" startup. It's crows, because everyone who studies them or lives alongside them in cities already has this sneaking suspicion that crows could probably do it. And that suspicion is not unfounded. Urban crows in particular have become extraordinarily good at reading human behaviour, at navigating human-built environments, at learning the rhythms of our cities. There's documented evidence of crows in Japan that learned to place walnuts on pedestrian crossings, wait for cars to crack them open, and then retrieve the nut when the light turned red and traffic stopped. They cracked the traffic light system. They're out here problem-solving with our infrastructure as their toolkit. And that's not a metaphor. That genuinely happened. So while the Swedish cigarette crow startup may have come and gone, the idea it was built on — that crows are capable, urban, socially sophisticated partners in a human world — that idea is very much alive. Wren: And speaking of ideas that are alive — let me leave you with one last thought, because it ties everything together beautifully. There's a piece from BBC Science Focus recently about Aesop's fables and what science has gotten right and wrong about the stories those ancient tales were built on. And one of the fables, of course, is the crow and the pitcher — where a thirsty crow drops pebbles into a narrow-necked jar to raise the water level and get a drink. For centuries that was treated as a charming little story. A fable. A moral lesson dressed up as a clever bird. And then scientists actually tested it. On crows. And the crows did it. They selected appropriately sized objects. They dropped them into the water, not into a dry container next to the water. They problem-solved in ways that showed genuine causal understanding — they weren't just copying a behaviour, they were grasping the physical principle. Aesop may have been writing fiction, but he stumbled onto something real. And I think that's the thread running through everything we talked about today — from mob tactics to neuroscience to Swedish litter programs to ancient fables. Intelligence is not a uniquely human invention. It evolved, in parallel, in feathers and hollow bones and a brain the size of a walnut, because the world is complicated, and complicated worlds reward the minds that can meet them. Bird Brains, brought to you by Ada, Ago Consulting, and Zen Semiconductor. If today's episode made you look at a crow a little differently — good. That was the whole point. Subscribe wherever you get your podcasts, leave us a review if you're feeling generous, and share this with someone who could use a little crow-shaped wonder in their week. Show notes with links to everything we talked about today are waiting for you — the link is in the show notes. Stay curious. I'll see you next time.