Instant Genius - Crows, rooks and ravens, with Dr Kaeli Swift

Episode Date: January 31, 2022

Ornithologist Dr Kaeli Swift tells us all about corvids, from their lifestyle and intelligence to how you can befriend a crow. Once you’ve mastered the basics with Instant Genius, dive deeper with Instant Genius Extra, where you’ll find longer, richer discussions about the most exciting ideas in the world of science and technology. Only available on Apple Podcasts. Produced by the team behind BBC Science Focus Magazine. Visit our website: sciencefocus.com Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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a bite-sized masterclass in podcast form. I'm Alice Lipscomb Southwell, the managing editor at BBC Science Focus magazine. In this episode, I talked to Dr. Cayley Swift, a bird specialist with a particular interest in Corvids. She tells us all about Corvids, gives us a scoop about their lifestyle and intelligence, and reveals how you can befriend a crow.

You study Corvids, So just to start off, can you tell us exactly what is a Corvid? That is a terrific question. So Corvids are a kind of songbird, actually. Ravens are, in fact, common ravens, so the one in both of our necks of the woods are the biggest songbird in the world. And Corvide is a family then within that umbrella of songbirds that includes crows, ravens, magpies, jays, rooks, jackdaws, and chuffs.

I didn't know they were songbirds because they don't sound like they sing like other birds, do they? Yeah, so songbird is a little bit of a tricky name because actually what the designation of songbird is based on is both the positioning of the feet and most importantly the anatomy of the vocal area. And so that's the features that these birds share with other more familiar songbirds like robins and tits and sparrows and all that kind of thing. does there anatomy look any different to those songbirds then? Because a crow make like a gaw, gaw, gaw, noise rather than singing like a blu-tit or a chaffinch or something. So human beings to produce the sounds that we do have what's called the larynx. And most birds, including songbirds, have instead what's called eight syrinks. And so the anatomy does differ a little bit across groups, but the ravens is going to look pretty similar to other

kinds of songbirds. The main difference, though, between crows and ravens and other types of songbirds has less to do with their anatomy and actually a lot more to do with their brain. And one of the really interesting aspects about crows and ravens is that they can learn new sounds throughout their lives, whereas most songbirds actually have a very short window of time when they're young where to learn every sound that they're going to make, and then that window closes and that's it. They don't make any changes moving forward. But that's why crows and ravens have these really, really impressive, and magpies have these really impressive vocal repertoires.

Because I've seen some videos online where you might get crows and magpies who maybe people have rescued them and they can almost teach them to talk, can't they? They can, yeah. So these birds are really impressive vocal mimics. And part of the reason that they can make such a wide variety of sounds, including human speech, but perhaps more impressively mimicking other kinds of noise-making objects is because they actually have independent muscle control on either side of their syrin. So they can actually produce two different sounds at the same time, which our vocal situation

doesn't allow us to do. So for us in the UK, some of our most common corvids are crows, rooks, and ravens, but people quite often get those confused. Is there a way you can tell them apart really easily? Yes, you should come play crow or no with me on Instagram. and Twitter or wherever every Wednesday because it is just a skill that you need to work on. It takes practice, but there are definite tools that you can accumulate and you can get really good at it. The main features to look for between crows and ravens, for example, and carrion crows are the

main crows that you all have over there are one size. Ravens are quite a bit bigger than carrion crows. The second feature is if you look at the throat, ravens have these really kind of rough, heavily textured throat feathers called hackles, and they will puff them out or smooth them down in different kinds of visual displays. So those can often be very prominent and easy to see versus the throat of a carrion crow is smoother, although it's a little rougher compared to like an American crow. But it's very distinct from the raven. And then the last feature is the shape of the tail. And that's a really helpful one if they're in flight. So ravens, when they fly have this kind of wedge-shaped tail.

Some people like to think of it as a V for Ray V versus crows have a more square or rounded tail shape, like a C for crow. And then the last one you asked about is the rook. And rooks are, once they've had their first adult molt, are really easy to distinguish because they lose all of the feathers at the base of their beak. And it gives them this really long-looking bill. this very kind of chalky appearance. And we don't quite know why that happens. It probably has to do with the fact that rooks are very insectivorous, meaning they eat a lot of bugs. And so they're

probing into the grass. And it might just be sort of a hygiene thing that they lose those feathers. But looking for that is a really, really key indication. And then eventually, if you want to be an expert at this, you could start to learn the differences that will help you tell a first-year rook apart. But that takes a lot more practice. So will all those species live quite gregariously? Because you hear about rookeries where we've got lots of nests and all the rooks are together, but will crows and magpies and ravens, will they live together as well? So that's a really good question. And there's sort of two different answers. So rooks are the only corvus bird meaning. So you asked earlier about Corvide,

which is a family. And that includes lots of different things. And then if we're thinking about how we sort animals, right, into little categories, the next sort of step down from family is genus, and that's the corvus genus. So that includes crows, ravens, and so if you look at their scientific name, you'll see that they all start with corvus, corvus, corvus brecky rancos, corvus, c, rogues, rooks are the only corvus species that are colony nesters. So they're actually very unique in that respect. However, both crows and ravens, even though they won't nest close to each other in the fall and in the winter, they do like to have big slumber parties.

So they will get together at night and do what we call roosting. So they have these communal roosts. So all of those groups are very social. They do like to gather up. But exactly how that manifests across their behaviors is a little bit different from species to species. So you touched it briefly then.

You said rooks may have these balder beets because they're foraging for insects. But in general, what will the call if it eats? So they are generalists, generally speaking, but we see different proportions of food depending on the species. Ravens are more carrion specialists, so they're going to be eating more animal tissue, particularly in the form of scavenging. But they'll actively depredate living animals as often as they can. It's just they're not super well made to do that, like a raptor is. so they don't do it all that often.

Because crows tend to be more urban birds, as opposed to wildland or rural birds, we see that their diet has a higher proportion of human garbage. But they're also like rooks eating a lot of insects. It's just not quite as highly represented in their diet as it is in a rooks, whose diet is mostly bugs. So you said there that crows are quite happy living among us, they'll eat our rubbish. Why don't they avoid us like a lot of other birds do? That's a great question. So crows are what we would describe as a synanthropic species, which is a word meaning an animal that doesn't simply just adapt to kind of the anthropocene to these human-dominated landscapes, the way that a robin does or any of the birds that come to a typical backyard bird feeder do. These are animals that really seek out human landscapes. They actually actively seek out the kinds of environments that we create.

So, yeah, you won't really find these birds avoiding us, though they are very cautious of us. They pay very close attention, kind of sorting out the friends from the foes. But in general, we are actually creating landscapes that they really like to be in. And that comes from the fact that we, you know, when we tear down forests and erect suburban neighborhoods, that's what they like. They don't want to live in big tracks of untouched woodland areas. They want a few really nice tall trees in the neighborhood, just like we do, to be. put their nests in. They like the industrial grass yard to look for bugs. They're one of the few wildlife species that can take advantage of the yard. And then of course, they like all of the

garbage we make. Far from being put off by the ways that we change the landscape, these birds actually really actively seek that out. So how can I befriend a crow that if one's coming to my garden? Is there anything we can do to build their trust? There is. So like any human being you'll ever meat by and large, one of the key ways to their heart is food. We all love to be, you know, invited into somebody's world through the gift of mutual nourishment. And it's pretty easy to do with crows. Really, the main takeaway is that it's much easier to overdo it than it is to underdo it. You always want to start with a small amount as you can. And your goal should not be to feed or sustain any particular bird.

Your goal is just to form a relationship. Give them the occasional treat. Kind of catch their attention a little bit. One of the best things you can offer is just pet kibble because it's easy to get. It's very high in protein. And yeah, easy to keep around low mess. And it doesn't have the same kinds of issues with nut allergies that feeding them things like peanuts might.

Because what these birds will often do is, after you give them food, once they've had the little nibbles that they want right in that moment, they'll go and do what's called caching, meaning hiding the food around your house or around the neighborhood for later consumption. And so if you're feeding them something like peanuts and the neighbor down the road has a really intense peanut allergy and those birds are stashing them all through their garden, that person might have a big problem on their hands come springtime when they're trying to put in the new veggies for the season. And so with the same, crows keep coming back to your garden and it wouldn't necessarily be different ones every day.

They will have their patch. They'll come back to and if you start feeding them, they'll want to keep coming to you. Yeah, that's really, to me, that's one of the most interesting and enjoyable parts of these birds is that unlike, you know, the experience of just putting out a bird feeder where you have this variety of sort of anonymous characters that are coming through, crows are territorial. So they also live a long time and they form permanent pair bonds. And so when you put all of those three things together, what it means is that a bonded pair of crows will establish a territory, and they will hang out there day in and day out for many, many years to come. So if you do start putting out just a few pieces of pet kibble every day, getting their attention,

and they start coming around and developing that relationship, that's a relationship that can last for more than a decade if all things go right. You said there that these birds will form paired bonds. How long are we talking? How long can these birds live for? So it's not unusual for crows to live anywhere between 14 and 17 years old. Obviously, there are things that can happen. And the most precarious periods of their lives are when they're young.

But if they can sort of get out of the gauntlet of youth, so to speak, if they can survive that, then their survivorship is actually quite high and they can live quite a long time. I didn't know it was that long because you think with songbirds generally they just live like a year or two. but 14 to 17 years, that seems incredible. Yeah, yeah, they're a very long-lived species. I think the oldest wild living crow on record was 29 years old, actually. You said there you get the pairs of crows. So is it easy to tell apart the males and the females?

It is not. So males and females, there's a slight size difference, but unfortunately there's so much individual variability that unless you have a pair, you know, where it's really obvious, there's a very big difference. It's generally, like, you're never going to see an individual crow and say, oh, I can tell that that's a male versus a female. If they're sitting right next to each other and there's a really big difference, you might be able to suss it out, but that's really the only way there's any sexual dimorphism in these animals is just purely in size. And so if you are a crow watcher, you've been getting to know a pair, and you want to figure,

out who is who, my recommendation is instead of trying to eyeball size differences, just wait until the breeding season, identify where they're nesting. Hopefully it's close to your home or somewhere in your neighborhood and then see who sits on the nest most often because that's going to be the female. So when you get a group of crows, it's called a murder of crows. Now, why is that? Because people are terrible. So murder of crows, unkindness of ravens, you know, parliament about, all of those are purely colloquial terms. They're not scientific terms. You'd never see me use that word and a paper and I choose not to use it in my everyday vernacular either, just to not perpetuate this sort of like icky feeling people have about crows. Yep, it's just, you know, one of those

little quirks of the human language. We just kind of came up for literary purposes for all the different names of all the animals, but they're totally made up terms by writers, not scientists. Now, I have to ask, is it true that magpies like to collect shiny things? We get told that they'll collect, you know, milk bottle caps and shiny jewelry and stuff like that. Is that true? So, I'm going to get myself in trouble on this one. So no. The answer is no.

That originates from a French play. I'm trying to remember when that play came out. But it is purely a rumor. However, however, and this is an important one. So we've done studies looking at magpies and how they respond when presented with different kinds of novel objects. And we find that, in fact, shiny objects really freak them out. If you give them piles of different things to choose between, they stay the farthest away from the shiny stuff to begin with. However, that doesn't mean that these birds aren't incredibly curious by nature and that there aren't examples of these birds seeking out things.

And so in Ireland, for example, I remember when I was in grad school, I had a Google alert on for crows. And there was just this spate of crows going to cemeteries and robbing the polished stones off tombstones. And people couldn't figure I was very distressing, obviously, because people put those there for ritualistic purposes. And so having them stolen by birds was very aggravating. I don't try and perpetuate this myth that they like shiny things and that they have this preference for. caching things. But at the same time, I want to honor and recognize that people witnessing them taking things is very true. Probably the disconnect between those two things is because this reputation exists, we tend to really notice when they take something that's shiny and we talk about it more

versus when they just steal the, you know, plastic placard off of your garden. You know, you're like, I don't know. They just did that weird thing. Who cares? But then they steal the shiny one and you're like, oh, yes, see, that's, that's that thing they do. I knew it, I knew it. It sounds like a confirmation bias then, really, isn't it? You see them doing it once. You're like, yeah, that's what they do. Precisely, yes, it's confirmation bias. At least as far as we know, you know, at the present time. I suppose relatedly, talking about sparkly things or shiny things, some people have said that crows will bring them presents. There was something in the news a few years ago

where there's little girl had a crow that kept bringing her gifts. Is that quite a common behavior? It actually is a pretty common behavior. Now, I will hedge that a little bit by saying, you know, if you feed crows regularly and you've never been gifted something, don't take it personally. I think common in this context means it's happened repeatedly across a wide variety of places, but I don't mean to use that to imply that someone should expect that that would then happen. into them. But yeah, they do seem to engage in this in this behavior. Now, is it really gift giving? Is it really a gesture of gratitude? I can't say. I can't speak to the crow's motivation. It could just be an accident that we interpret as gift giving. It could be a behavior that they've learned. They don't really

understand why we like it, but they have learned to recognize that when they do that, we reinforce them with food and so then they keep doing it. Or maybe it really is a gesture of gratitude. That then bakes the question if you've been feeding your pair of crows for 10 years and they've never brought you anything, does that just mean that your pair are jerks that are not so grateful to you? And so you can get into some kind of messy waters there. But certainly the experience of I feed crows every day in this one particular place and I've noticed that they've left something behind or they've started a pattern of leaving things behind is real. So how intelligent are Corvids then? If you're saying they're perhaps recognizing we're

giving them something they want to give us a gift back, they can speak, they can learn new things. How smart are they? How can we actually measure that? So Corvids are incredibly smart. One might make the argument that primates are really about as smart as a crow. There's a variety of ways that we've been able to assess that. And there was actually a paper that came out just a few years ago that did the best job to date of trying to make an as close an approximation in the cognitive abilities of primates and ravens that had ever been conducted. Because one of the challenges to studying intelligence is making sure that your tests make sense and are executable by the animal in question, right?

Crows and ravens don't have hands. And so there's a lot of tests that we give to chimpanzees to evaluate their intelligence. that we simply can't give to a raven because they couldn't participate in it. But there are sort of a variety of categories like analytical skills, their ability to understand quantities, their problem-solving skills, their ability to understand cause and effect, their ability to cooperate or pick up on social cues, right? There's all these different kinds of categories that we understand speak to intelligence on a pretty high. cognitive level. We've been able to demonstrate that in humans and primates, etc., etc. And so more and more,

we've been able to design those kinds of tests that are appropriate to be given to crows and ravens, and we see that the performance is often quite similar to what we see in primates. And what's about things like the mirror test, because that's one we use a lot with primates, and that's shown as a sign of intelligence. If we draw a mark on a bird, or can they then recognize that mark and try and remove it when they look in a mirror? So they're really bad at the mirror test, weirdly enough. Now, if you ask somebody who reads a lot of popular science articles, they're going to think, what? I've definitely seen that mag pies pass the mirror test. I've heard that a million times. And that's true. So there was two common magpies that

passed the mirror test. They put a little spot on their breasts and they put them in front of a mirror and they've pecked it off. However, we then repeated. that exact same study with jackdaws, and we found that they responded exactly the same way, regardless of if the patch was a different color or the exact same color of their plumage. So if it was the control or the test, it didn't seem to matter. They were just as good at it. And so that kind of called the whole methodology of how we did that particular study into question. And since then, we've asked that with Ravens, we've asked it with American Crows. we've asked it with New Caledonian crows, and New Caledonian crows are the most sort of renowned corvids for their problem-solving skills because they're the ones that make tools.

And even they are incredibly bad at passing the mirror test, despite the fact, and this is the one that always gets me, the fact that New Caledonian crows understand what mirrors are and their properties. So New Caledonian crows can look in a mirror and understand that the food right here is behind them. It's not in front of them. And yet they don't exhibit any of the what are called self-directed behaviors, which is what we look for when we put a dolphin in front of a mirror and it opens its mouth and checks out its teeth or it cleans itself. So there's this question of maybe the mirror test just isn't a very good test for these animals. It's not that they're not self-aware. It's just that that test isn't getting at that question. So you touched on it there that the New Caledonian crows used tools.

What sort of tools are you talking about here? So they make a variety of tools, most impressively hooks. There's not even a primate that makes hooks. So it started with, so there's a plant that's native to the area they live called the Pendanis plant. And Pandanis is this really rigid plant with a serrated edge. And so the birds will peel off sections of the edge of this Pandanis plant and then whittle it. down to the appropriate size and stick it into the crevices of logs and rotting wood to pull out grubs, very similar to how chimpanzees will take twigs and then modify them so that they can

extract ants. But then beyond that, they'll also take snap off branches and modify them in ways that the resulting tool meets the minimum definition of a hook, which is incredibly, incredibly impressive because while tool use is very rare in the animal kingdom, only about 1% of the animals use tools, it is within that group very widely represented, anywhere from sea otters to human beings to certain kinds of fish like rass. But making tools, actually taking objects and modifying them, that is much, much more rare and is really only represented in crows. recently we found this in a parrot and then a couple of primates. I'm not sure if it was a new Caledonian crow.

I remember hearing a story about these crows that learned that they could drop nuts down onto a pedestrian crossing, wait for cars to drive over and smash the nuts, and then they knew when it was safe to go down there and collect all the goodies. So is that story true? So that's a true story, but that was actually carrying crows in Japan that learned how to do that. And that was a really interesting one

because that behavior started at a driving school. Somewhere in Japan, I can't quite remember where, and people noticed this and they started tracking this behavior and they found that over the next decade, the span of birds that exhibited that behavior was growing and growing and growing, suggesting that this was, this knowledge was being culturally transmitted across the crows in that area. That's incredible. Would they have been teaching it to each other? Would they have just been observing it and then learning from other crows doing it?

Yeah, so most of the learning that happens in crows is, probably done through observation rather than active teaching. And actually the idea of whether or not animals can, you know, a non-human animal can teach someone is a topic of continuing disagreement, largely because anthropologists keep moving the goalpost of what teaching is. Every time we have an animal, like an ant, that seems to meet the definition. They go, no, no, no, no. Actually, this is what teaching is. So that doesn't count anymore. Thank you for listening to this episode of Instant Genius. That was Dr Kaylee Swift.

If you want to find out even more about COVIDs, you can follow Kaylee on Twitter or Instagram. She's at Corvid Research, and join in every Wednesday with her Crow or No Challenge. To hear her tell me even more about COVIDs, head over to the Instant Genius Extra podcast now. The latest issue of BBC Science Focus magazine is now available. Pick up a copy in store or visit sciencefocus.com.

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