SciShow Tangents - Migration

Episode Date: November 3, 2020

It’s our 100th episode! And to celebrate our migration from double- to triple-digits, we’re talking about… animal migration... Ok, we forgot it was our 100th episode. But this is still a great episode!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Stefan: @itsmestefanchin Ceri: @ceriley Sam: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links: [Truth or Fail]Arrow Storkhttps://www.mentalfloss.com/article/76208/how-stork-solved-scientific-mysteryhttps://www.realclearscience.com/blog/2018/02/19/the_weirdest_ideas_about_bird_migration.htmlhttps://www.atlasobscura.com/places/zoological-collection-of-the-university-of-rostockhttps://labandfield.wordpress.com/2013/11/03/bird_migration/[Fact Off]American and European eel migrationhttps://www.jstor.org/stable/2449503?seq=3#metadata_info_tab_contentshttps://www.bbc.com/news/science-environment-37563100https://jeb.biologists.org/content/208/7/1329https://www.nature.com/articles/ncomms9705https://www.discovermagazine.com/planet-earth/mystery-of-the-vanishing-eelshttps://advances.sciencemag.org/content/2/10/e1501694https://oceanservice.noaa.gov/facts/sargassosea.htmlArmy ant bivouac [Ask the Science Couch]Forest migrationhttps://earthobservatory.nasa.gov/features/BorealMigrationhttps://www.npr.org/2020/07/28/896030567/believe-it-or-not-forests-migrate-but-not-fast-enough-for-climate-changehttps://daily.jstor.org/the-incredible-moving-forest/[Butt One More Thing]Starling poop https://www.bloomberg.com/news/articles/2016-01-05/rome-is-drowning-in-the-droppings-of-a-million-migrating-starlings

Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen. We are, guys, I'm a little bit bummed that Halloween is over. Yeah. We all have normal names again. It's boring now. This week, as always, I'm joined by Stefan Jinn. Hey.

What's the best nutrient? Oh, protein. I mean, you need them all, okay? All the macronutrients, all the micronutrients. Yeah. A, B, C, D. C, D, E. Not F.

You don't need F. Stephan, what's your tagline? Slapdash Piston Machine. Perfect. Oh, I like that one. Sam Schultz is also here today. Hello, Sam. What's your tagline?

To everybody out there listening on election day, how's it going? Is it election day? Yeah, that's when this one goes up. Oh, Lord. I'm glad that we're just going to go ahead and do this one on a topic that has nothing to do with that. Yeah. Just be distracted. Spend some time with us. hopefully everything is on the rails sari riley is also here hello sari what's your tagline

meep more great perfect and i'm hank green and my my uh my tagline is poke a mole every week here on tangents we try to get together to one-up a maze and delight each other with science facts. We're playing for glory, but also we keep score, and we care a lot about who wins, unless we're deeply behind, in which case we've stopped caring. We do everything we can to stay on topic, but judging by previous conversations, we're not always great at that.

So if the rest of the team deems your tangent unworthy, we'll force you to give up one of your sandbox. So tangent with care. Now, as always, we will introduce this week's topic with a traditional science poem this week from Stefan. This behavior spans many animals, big, small, and in between. A mass movement to a new place, a search for pastures more green. For reproductive purposes or because of a lack of good munchies, or because of the changing seasons you munchies or because of the

changing seasons you feel like you might just freeze from a jellyfish that swims daily back and forth across a lake to a young elk following the herd learning which path to take to a salmon swimming upstream to fill the river with roe to the arctic tern who travels the farthest don't you know they say it's not looking good here. Our conditions can only improve. So pack it up, kids. It's time to move. Hurry up now.

There's no time to dilly dally or delay. And you can leave that behind. We'll be back here one day. One last example, an insect living its life on the ice, migrating higher up the glacier, using the sun as a compass device. That's part of the harsh life of the Himalayan wingless glacier midge. Meanwhile, I'm over here migrating from the couch to the fridge.

Oh my God. Incredible. That was maybe three different poems smushed together into one longer poem. Oh God, the topic of the day is migration, That was maybe three different poems smushed together into one longer poem. Oh, God. The topic of the day is migration, which is an amazing thing. I don't know at what point it becomes migration because, yes, I do have to go to the fridge to get food, but that's not migration. So, Sari, what is migration? I don't think I'll have a better answer for you. It seems like it's defined pretty broadly of just the movement from one region or place or habitat to another.

And then it can be a seasonal movement. So they move to a different habitat and come back. But we also use migration to refer to just movement in general. So this is the cell biologist in me coming out. But you can talk about the migration of cancer cells. You can talk about migration just as movement from one place to another. Not necessarily like a herd of animals tromping across the plains. Can non-organic things ever be migrating or described as migrating?

Like rocks or something? I say no. Because it's sort of like you're responding to some kind of stimulus or reacting to like a need and i don't know doesn't do that this paper in applied ocean research the migration of sediment deposition due to the construction of large scale structures in the Shenzhen estuary. I'm down. So it just is moving. Just any movement. I don't know why

we just don't use that word at that point. Science. It's a science word. Because like orbits change over time too. And I guess you could say the orbits are like

migrating outwards or something like that. Yeah, yeah, yeah. The moon is migrating away from us, I think. I'm pretty sure. It'd be scarier if it was headed toward us. Do you think the world would be different

if we knew the moon was going to smash into us one day? If it was, like, fairly soon, yes. But, like, we already know that the Earth is eventually doomed. Like, that's... I guess anything where we know that it's over within our lifetime would change just, like, orgies all over the streets. Oh, God. Not on the streets.

I was thinking like blowing up the moon. Oh, yeah. We'll blow up the moon. Yeah, the world would change because we'd blow up the fucking moon. We'd figure it out one step at a time. It's a pretty big moon. You're right. We'd figure it out. We'd a time. It's a pretty big moon. You're right. We'd figure it out.

We'd all be raised to hate the moon. Fucking moon. Rage, rage at the moon. You orb of doom. Fuck you, fuck you, fuck you. Well, anyway. So we don't know what migration is. Do you have anything about the etymology of migration, Sari?

Just more of the same. So migration and migrate both come from the Latin migratis, which is the past participle of migrare, which comes from the Proto-Indo-European root mei, so just may, I guess, which means to change or go or move. So we've had to describe movement for a while. This root shows up in words like migration, but also mutation, but also commune, communicate, immune and immutable. And it seems like migration started out as a word to apply to humans, like moving one place to another. And then around the 1700s or 1800s, we started using it to mean animals

going from place to place. And now it's time for Truth or Fail. One of our panelists has prepared three science facts for our education and enjoyment, but only one of them is real. The rest of us have to figure out, either by deduction or wild guess, which is the true fact. And if we do, we get a Sam Buck. If we're tricked, then Sam will get the Sam Buck.

You can play along at home at twitter.com slash SciShowTangents, where we will put up the three facts for you to click on, so you can see how you measure up against us geniuses. Sam, what are your three facts for you to click on so you can see how you measure up against us geniuses. Sam, what are your three facts? For as commonplace as the idea of bird migration is to us nowadays, it befuddled scholars all throughout the history of the Western world. Aristotle proposed that birds he saw in spring

were metamorphosing into the birds he saw in summer, for instance. Oh, wow. And British scholars thought that birds hibernated underground like toads. And some people thought birds might even grow on trees. But eventually, a completely coincidental discovery gave a key piece of evidence that some birds did indeed travel

all over the world with the seasons. Which of these was that discovery? So number one, in 1822, a hunter in Germany shot a white crane and upon gathering it, found that it had a strange arrow stuck in its neck. After some examination at a nearby university, the arrow was found to be made of wood native to Africa. So apparently the bird was almost the victim of another hunter in Africa before flying to Germany and getting killed there. and getting killed there. Number two, in 1900,

a muralist hired to paint the interior of a home in Scotland, washed his brushes and dumped his leftover oil paints in a nearby pond. A flock of Arctic skua landed in the pond shortly thereafter, staining many of the birds robin's egg blue,

much to the horror of the home's owner, a naturalist and early member of the British Royal Society for the Protection of Birds. A month later, he received a letter from a fellow member of the RSPB expressing amazement at a flock of blue Arctic skua he had spotted while birdwatching. Or number three, in 1856 in Los Angeles, an Amazon parrot escaped its owner's home via an open window.

Five years later, it appeared in a tree outside of the home, mimicking the voice of its owner. When the owner recaptured the parrot, he found a price tag tied to the parrot's ankle. The tag was written in Peruvian Spanish. Okay. These are amazing. Very good. We've got three potential ways

to help us figure out how migration was happening. A crane found in Europe with an African arrow stuck in its neck. Paint-covered Arctic skua spotted by two distant naturalists. Or three, a pet Amazon parrot escaped and returned five years later with a Peruvian price tag. Do parrots get price tags tied to their ankles? Maybe not now, but in the 1850s. So that part seems reasonable. I don't believe, based on no knowledge whatsoever,

that a parrot can travel across the ocean. Yeah, well, it went from Los Angeles to Peru. So it wouldn't have to go across the ocean. Yeah, it, it went from Los Angeles to Peru. Oh, Los Angeles. So it wouldn't have to go across the ocean. Yeah, it still seems far from it. It'd be chilling out on the beach the whole way. But a parrot doesn't go. A parrot likes to stay where it is. It told me.

Yeah, I mean, the idea that a parrot, which was presumably imported from the Amazon, would know how to get back. But I don't know, maybe. I've seen so many trailers for dog movies where the dogs like run across the country. It's probably way easier for a parrot, too. They can fly over all the danger that a dog would encounter. All the danger except for the arrows that people are shooting into cranes' necks. That one seems like totally legit to me.

That one seems the most fake to me because it's like, how would, I guess I don't know anything about archery. Can something be shot with an arrow and then still move? Yeah. If it's just a flesh wound and like if the arrowhead is fairly narrow and it just punctured instead of like creating a lot in real life, the arrow passes through unless it hits like a very big bone, in which case usually the animal is okay. You know, okay. I can often survive. Yeah.

The giant hole in its neck. Well, it depends on where, what part of the neck it is. Yeah. Yeah. That's true. I also,

I wondered if you could figure out by looking at a piece of wood, like I know this African wood, but I bet you could though, like carpenters now, like, like, like if you have a friend who's into carpentry, they'll walk into your piece of wood like, I know this African wood, but I bet you could though. Like carpenters now, like if you have a friend who's into carpentry, they'll walk into your house and be like, oh, that's nice. Is this pine?

And like, oh yeah, that's pine. Like they just know. They'll like look at the wood, be like, this wood's not from around these parts. Or however, a German person, is it a German person who found it? Yeah. This wood's not from around these parts.

Yeah. And then the paint covered Arctic. How do you say it? Skua? I say skua. I'm pretty sure it's skua. Skua? Skua.

I think it's skua, but if Sari can keep saying skua, that'd be good. But that seems also reasonable. I don't know how oil paint would stick to feathers. And if it would, I've just seen this images of like birds and oil slicks where it seems to like severely impair their ability to do it. But a little bit in a puddle seems maybe fine. I think it could totally work. Yeah.

Yeah. I think it could totally happen. The harder to believe part is like by chance chance, he had a distant naturalist friend who wrote to him to just like, I saw a bunch of blue skuas. And they didn't have TV back then, so, you know. I guess you would write, if you saw a bunch of blue Arctic skuas,

you'd be like, hey, I saw a weird thing. Well, I'm going to go with my first instinct, even though Sari kind of has brought me around and say the crane with the arrow in its neck. I'll go with the squaw. I'm also going to go with the crane. Oh, Sari threw a curveball here, which makes me feel real good.

I could see it in your eyes that you knew that it was the crane. Tried to lead us astray, too. Yeah. I'm playing the game. I'm playing the win. I'm playing the Unseri Bucks. So the crane is true.

It was called the Fjallstors, which means arrow stork. I guess, I don't know. They're different birds, but they called it an arrow stork. Probably sounds better. Or maybe they didn't have a word for crane. I don't know. birds, but they called it an arrow stork. Probably sounds better. Or maybe they didn't have a word for crane. I don't know. And as goofy as it seems, it was widely cited from what I could find to be the discovery that helped us start to figure out where birds were going and the fact that they were

even going anywhere in the first place. And it's still on display at the University of Rostock, which is in Germany, which is the university it was taken to when it was discovered in the first place. And since 1822, about 25 more feel-storch specimens were discovered. I'm looking at a picture of the arrow stork now and I was imagining like a splinter. Oh, no, it's stuck right on through the neck. It's got a full arrow in it. And it is adorned.

The thing I read said it was the wood that tipped them off, but the adornment probably also. The carving helped. It does not seem pleasant, but I guess I can see how it maybe survived. You make it work. And then he gets freaking shot in Germany. Yeah, that's the sad ending of the story.

Tries so hard and then gets shot in Germany. And 25 others that were shot once survived and then shot again and died. So Stefan, the blue skua, that story is not true at all. I made it all up. They do travel from Scotland to New Zealand. And while I was trying to find other birds to lie about, I saw a painting of a family from Scotland going to New Zealand. And then I just let the old imagination take it from there. And Amazon parrots and almost every kind of parrot, Stefan was right, they don't migrate at all.

That's right. I should get a point for that. There are two types of parrot I found that do migrate, and they both migrate from Australia to Tasmania and back again. So not the farthest, but there are two. Well, Sam, that was a banger. I loved it. The existence of the aerostoric is something I will never forget.

I only got one freaking point out of it, but whatever. You'll survive. Now it's time to take a little break, and then it'll be time for the Fact Off. Hello, welcome back, everybody. Easy to tell you what the Sandbox score is right now because it's a four-way tie. So it's down to me and Sari to figure out if we can, which one of us might pull into the lead here, because it's time for the fact-off,

where Sari and I have each brought facts to present to the others in an attempt to blow their minds. You each have a Sandbuck to award the fact you like the most, and we're going to decide who goes first with this trivia question. Salmon are famous for their upstream migration from the ocean to the creek bed where they were born. This is where they spawn, and then usually they also die there. While all Pacific salmon die after spawning,

some individual Atlantic salmon, usually females, migrate back to the ocean and then repeat this migration and spawning process again. So what is the record number of spawns and thus complete river- river migrations for an Atlantic salmon that we know of? Wow. Hmm. Interesting.

I didn't know this. And I'll just go first and say four. I'm going to go with six. Six. But what if it's five? If it's five, then no one will have gotten it right. You can't choose six. It's not allowed. Okay. Seven. Six? Six, but what if it's five? If it's five, then no one will have gotten it right. You can't choose six.

It's not allowed. Okay, seven. The answer is seven, so serious right on. That's an old-ass fish. That's an old-ass fish, let me tell you. That's a lot of times to say, fuck it, I'm not dying. Let's go one more time. I can do this again.

Good for her. All right, Sarah, do you want to go first? Yeah, my fact is related, so I think it'll be good. So here are some things we know about American and European eels. One, they're in the family Anguillaidae with other freshwater eels. Two, they're long and snake-like and have a mucousy sheen on the outside. Three, if you like seafood, they can taste good. Here are some things we don't know about the American and European eels. How they all migrate to the Sargassus Sea to mate and have babies. And honestly, what do they even do there? And how

do the babies go back to where the adults came from? Scientists have been puzzled by their mating habits and migration habits for centuries. Aristotle, being the man that he was, said that eels must have spontaneously came from the earth like worms. Aristotle didn't know shit about migration. He was just like down. Everything comes from below. Yeah. But what's weird is our understanding isn't that much better than that. So until around the early 1900s, scientists and fishermen had pretty much only seen adult freshwater eels, but knew that they had to be babies at some point. So the Danish biologist Johannes Schmidt sort of made it his career's mission to figure out where the babies came from. So because no one had found baby eels in rivers, the next most logical place to look

was the river mouth in the ocean. So he basically just sailed out to sea and cast nets until he caught smaller eels. In 1904, he caught a slightly smaller eel near Iceland and then he just kept going further and further and catching tinier and tinier eels until around 1920-ish when he was like, I don't know, the smallest ones

seem to be in the Sargasso Sea. What? He just dragged them back. Yeah. He just caught eels his entire adult life. What the weird thing is, though, in the Sargasso Sea, he never caught adults. So he was like, the babies are coming from here,

but I've never caught an adult here. And the Sargasso Sea is a very weird place anyway because it's just like a salty, deep part of the ocean with a particular kind of seaweed and no land borders. There are four swirling currents that define it. So it's a mysterious place. And then the eels are having mysterious sex there. Around 2012, scientists in Nova Scotia caught around 38 eels, so American freshwater e eels attached satellite tags and released a few of them each year in the fall of 2012, 2013 and 2014 into the Atlantic. 30 of them were eaten by sharks or other things before they even made it into the open ocean. And eight successfully made it to the open ocean.

And only one was tracked for the full 2400 kilometers to the northern is-ish part of the Sargassus Sea before their tracker got messed up. And this was very, very thrilling for scientists because it gave the first conclusive evidence that American eels did migrate to the Sargassus Sea. Because in a separate five-year study published in 2016, European scientists tagged 707 eels and none of them made it to the Sargassus Sea. Only 80-ish made it to the open ocean the rest of them got eaten got lost whatever so apparently it's like very hard to track eels or there's a really high death rate a side note this is already weird but i would like to point out how it's very weird to me that two different species go to the same part of the ocean to mate they're just like ah, we have this evolutionary instinct

to swim into this weird patch of ocean that is only defined by ocean currents and squirt our eggs and sperm in, mix it together. Scientists call it panmixia because they just think it's like a fertilization mess and we have no idea what it looks like because we've never seen it outside of

a lab. Then we don't know how these less muscular baby eels spend two to three years floating or swimming back towards freshwater rivers. There were a couple studies in a lab and Norwegian fjords about how baby eels have some sort of magnetic navigation abilities that they hold until they're adults that probably steer them towards currents that help them toward their destination. But with all these adults dying and being eaten, how are the babies making it? I don't know. Eels are a mystery.

And people are worried about this because humans are eating a lot of eels. So we've got to start saving them, but we don't know how to save them without knowing where they are. And we don't know where any eels are, apparently. Wait, so where's the Sargossa Sea? In the Atlantic Ocean.

It's like off the coast of Canada, like south of Iceland and like way farther away from Europe. So it's a shorter journey for the American eels than the European eels. And they can't interbreed with each other, can they? I don't know. I assume not because they're separate it's fine to be separate species but maybe it's just like i don't know if anyone has tried to mate uh an american eel and a european eel because if they're all mating in one big frenzy who knows but maybe they have separate little pits can i just follow an eel can i and then like chase off the sharks because apparently that's a big problem and be like you're my baby eel and I will watch you day and night.

Because we need to follow the eel to the sex place. Okay. Is it my turn? Yeah. All right, everybody. So I don't know why I didn't know about army ants. But I didn't know about army ants. And there are kinds of ants that are basically always

either on the move or they're taking a brief break from being on the move. A colony has two phases. There is a 16 to 17 day nomadic phase where the ants are moving from place to place and a 20 day stationary phase where they have actually found a place to live and they will stay there for a while. The stationary phase is the part where they make more ants. The queen will lay her eggs and the larvae start to pupate. And when that phase is over, the colony, which ranges in size from 100,000 to 2 million ants, goes back to its nomadic state, carrying the larva around while also hunting for food. During the nomadic phase, the army ants go on foraging raids where you can see these like meter long lines of ants spanning across the forest floor, taking down whatever food they can find. But while they are in their

nomadic phase, they don't have a place to relax and stay safe, except they do. They make a new nest at the end of every day. And that might sound like it'd be really cumbersome and really laborious. You have to find all the material to make it. But army ants have found the perfect building material for their nests. It's always available. It's always ready to go and cooperative because they build their nests out of their own bodies so they they these are called bivouacs and they connect to each other using little hooks on their feet and the nests can vary with environment and with species but these living nests don't just allow the army ants to rapidly assemble and disassemble to get back on the road they also actually like create the specific environments necessary for their young

and their queen to make the next generation they adjust as the colony moves through different stages of that process scientists have studied the thermal gradients of bivouacs. And early in the nomadic phase, there's more like it's hotter on the inside to protect the brood. And then there's a sharp temperature gradient as it gets out to the walls. And the bivouac is really tightly packed.

And as the nomadic phase goes on, the larvae begin to mature and the colony starts being a looser bivouac structure, which creates a less sharp thermal gradient and it isn't as hot in the middle. So even with this instability of their lifestyle, where they're always on the move,

always trying out new stuff, army ants create an environment in which they can be safe and make the best situation for their next generation of ants ants when they are having babies is that two groups of army ants meeting or no no okay no so they have a queen and the queen is who is the the ant that gives so they like carry the queen around and try to keep her very very safe okay there's a whole thing lots of research has gone into how they protect the queen during their constant moving around.

And so, like, there's a very specific part of the army ant train. So, like, as they're traveling around, they form these really long trains. The thickest part is the part where the queen is. And she's always in the middle. Extends out in front for a little ways. And then behind, it's thicker for even longer, just in case, case like she falls behind they can keep her up because the main

thing it seems like is they're worried about her getting lost which does happen sometimes and if the queen just gets lost and you can't find her again the army ants either die it out or they have to go find another army ant clan to join with and they're like we submit

to your will and we'll be part of your army ant clan. We lost our queen. Can we borrow yours? We'll help. Jeremy there, he's really great at being a wall. Frank loves the window. So we have a lot to add to your house.

This is disgusting. Yeah, when you're margariting, you gotta have a place to sleep at night. I guess. And so you just build a house out of your friends. I guess so. So will you go with Sari? With her fact about knowing so few details

about the American and European eel migration, besides the fact that they go to the Sargasso Sea and have babies somehow in some way. And we have no idea. It's probably gross. Or my fact, where army ants make nests made up of army ants so that they can add some stability to their life on the go, which is also, according to you, at least, gross. This is maybe the hardest one ever. Yeah, I don't know. Three, two, one. Hank.

Okay. I'm glad we split. All right, that works for me. Yeah. That works for me. That feels fair. All right, now it's time to ask the science couch. We've got some listener questions for our virtual couch of finely honed scientific minds.

It's from at Scared Hippie who asks, how are the trees doing? Are the forests migrating as well? Is that a good thing or a bad thing? The main system of migration of forests, which is a thing, is the next generation

and the next generation and the next generation. And I would imagine that forests are migrating because the climate is changing. Though I don't know if they will be able to migrate fast enough considering the speed at which that is occurring. Sari, how is my bullshitting going? That's great. I don't have to do anything. You can just keep going and what you're going to say will probably be also the notes that I have on my screen because they are so far. The two main forces that contribute to forest migration are seed dispersal in one direction and then population retreat because of some sort of environmental selection in the other direction.

ways, like the climate becoming less favorable for those trees or like beetles eating them or, I don't know, predators and the way that plants can have predators, things that eat them or climate changing. But also now that humans are here, then deforestation and like more rapid climate change are affecting what is a pleasant place for a tree to be. Obviously, deforestation is a pretty intentional, you know, force for forest migration, but so could refore to be. Obviously, deforestation is a pretty intentional force for forest migration, but so could reforestation be. If we're in a situation where certain forests don't make ecological sense in the place where they are anymore because there's not as much water or the temperature is different, you could theoretically imagine us being like okay well we're gonna put the plants that would eventually move into this area we're just gonna make them move there now

so we could be like you guys can migrate faster because we can just drop seeds down yeah but they have a term for that the scientists they call that assisted migration just like the humans giving a forest a helping hand. You'll like it here, I promise. We've done the math. So how are the trees doing? Are they okay? I think they're in the same state of troubled as the rest of the planet. They don't feel worried, though. So that's a plus.

Yeah. They're not going to see it coming. Thanks for bringing a little happiness, a little silver lining to that cloud. Yeah, the trees are fucked, but they don't know that. Ignorance is bliss. And that's a tree. First spoken by a tree. If you want to ask the Science Couch your question, you can follow us on Twitter at SciShow Tangents,

where we will tweet out topics for upcoming episodes every week. Thank you to at Dorky Homestead, at Sneffin, and everybody else who tweeted us your questions for this episode. Final Sam Bucks scores. Sari and I tied for the lead with Sam and Stefan coming in behind, which means that Stefan is still in the lead and Sam and I are now tied. Oh, dear.

I may, I'm not last. Well, I am last. I'm tied for last. If you like this show and you want to help us out, it's very easy to do that. You can leave us a review wherever you listen. That helps us know what you like about the show and also oftentimes just brings joy to our hearts. Second, you can tweet out your

favorite moment from the episode. And finally, if you want to show your love for SciShow Tangents, just tell people about us. Thank you for joining us. I've been Hank Green. I've been Sari Reilly. I've been Stefan Chin. And I've been Sam Schultz. SciShow Tangents is a co-production of Complexly and the wonderful team of WNYC Studios. It's created by all of us and produced by Caitlin Hoffmeister and Sam Schultz, who also edits a lot of these episodes, along with Harula Matsushima. Our social media organizer is Paola Garcia-Pietro. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Medish.

And we couldn't make any of this without our patrons on Patreon. Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. So in winter, Rome is sometimes covered in white, but not the white of snow. It is the white of bird poop produced by flocks of starlings that can get into the millions.

The starlings are migrating down from Northern Europe to Rome and their poop storms can get so bad that people are walking around with umbrellas on otherwise nice days to shield themselves

and they have to deploy special cleanup procedures to make the roads less slick because they have an increase in like skidding accidents. Oh no. God. What do they have to hose the whole city down after, after special cleanup procedures. Okay.