The Science of Birds - The Terror Birds

Episode Date: October 13, 2026

👕 Bird Merch —  Get yourself some bird shirts!~~~Episode 139 of The Science of Birds takes listeners into prehistory to meet the Terror Birds: giant, flightless predators of the family Phorusrhacidae. Standing as tall as 10 feet, with axe-like beaks and sickle-clawed feet, these birds ruled South America for tens of millions of years after the dinosaurs disappeared.Host Ivan Phillipsen explores how an isolated continent, some of empty ecological niches, and the amazing process of evolution gave rise to these fearsome hunters. Along the way, the episode looks at how they lived, how they hunted, and how they ranged from “terrifying” to surprisingly small.Links of InterestTerror Bird scene - Life on Our Planet [VIDEO]The Time Terror Birds Invaded - EONS [VIDEO]Terror Birds: The Giant Birds With Guillotine Beaks [VIDEO]When Giant Terror Birds Were Apex Predators [VIDEO]Support the show

Hello and welcome. This is the Science of Birds. I am your host, Ivan Philipson. The Science of Birds podcast is a lighthearted exploration of bird biology for lifelong learners. This is episode 139. It's all about birds in the family, Forrest Rassidy. Forest Rassidy, that's spelled P-H-R-U-S-R-H-A-C-I-D-A. These are the terror birds.

That is probably the coolest name for any avian group ever. And some might say these are the coolest birds ever. But sadly, spoiler alert, the terror birds are all extinct. So today we are exploring the realm of prehistory and paleontology. For our purposes, the story of terror birds began 66 million years ago, on that epically catastrophic day when the Cheekshulub asteroid smashed into what is now the Yucatan Peninsula in Mexico. That event led to the extinction of all the non-avian dinosaurs. But many bird lineages survived, of course, including the common ancestor of the terror birds.

That ancestral bird was probably pretty small, and honestly not all that terrifying. It was most likely a ground-dwelling bird. a runner with long legs, a light build, and only a limited ability to fly. It was probably a generalist predator, hunting insects and small vertebrates like lizards and small mammals. Maybe sort of like a modern-day roadrunner or secretary bird. But millions of years later, that proto-terror birds' descendants diversified and they evolved into new gigantic species, gigantic, flightless species with massive beaks and feralds. fierce talents. Birds that, if they were alive today, would be truly terrifying to us, to humans,

because they could literally hunt and kill us. So long after the large non-avian dinosaurs had gone extinct, dinosaurs made a sort of comeback, but this time in the avian form. Don't call it a comeback! What's that, LL Cool J from 1991? Don't call it a comeback? Well, what should I call it, a resurgence, a rebound? Yeah, so as I was saying, dinosaurs made a resurgence in the form of these giant birds, because, of course, birds are actually dinosaurs. It's impossible to ignore the similarities between terror birds and the famous theropod dinosaurs of the Cretaceous period, like Tyrannosaurus and velociraptor, like those earlier large carnivores, terror birds were apex predators, and their domination lasted for millions of years.

I have been fascinated by the family Forrest Racity for what feels like millions of years, most of my life anyway. So I am super jazzed to finally be making an entire podcast episode about them. So let's go ahead and jump in and get to know the terror birds. To understand the evolutionary history of these birds, we first need to start. to get a lay of the land, as in what was the geographical and ecological context that set the stage for the rise of the terabirds? Well, the stage itself was the continent of South America. When the asteroid hit 66 million years ago at the end of the Cretaceous period, South America was no longer connected to Antarctica. In fact, it wasn't connected to any other landmass.

So South America was, in effect, a great big ice. island. It was isolated, much the way that Australia was and still is. And when a landmass or island is isolated for millions of years like that, it tends to spawn its own weird and wonderful collection of unique plant and animal groups. South America had about 52 million years of isolation, which is a lot of time for evolution to work its magic, to do its thing. During that time, most of the mammals in South America were marsupials, or at least marsupial adjacent. And South America is where the Xanarthran mammals evolved. Zenarthra is spelled sort of like X-N-A-R-T-H-R-A.

It's a super order in terms of its taxonomic rank. Zenarthra includes all the sloths, ant-eaters, and armadillos. And this group also included extinct megafauna fauna like, the giant ground sloths and the glyptodonts, which were those massive armored armadillo-like things. Anyway, in the early millennia following the Great Extinction, South America was humid and heavily forested, with tropical and subtropical closed canopy forests dominating areas as far south as Patagonia. But it was much later, during the Miocene epic between 23 and 5 million years ago, when large terabirds really hit their stride, when they were.

were most common, diverse, and widespread. And that was perhaps because during the middle to late Miocene, global cooling and drying caused South America's closed canopy forests to contract and fragment. Forests gave way to widespread savannas, shrublands, and grasslands. These open habitats were ideal for large predators that like to chase down their prey. So we've got a continent that's isolated,

from the rest of the world. We've got vast expanse of open habitats, and we've got lots of fat little mammals running around, just begging to be eaten. But 66 million years ago, South America lost all of its large predators in the big extinction. They had been all those non-avian dinosaurs, and then they were no more. And one quirk of South America's biogeography is that when it became isolated, it didn't have any of the placental mammal groups that became fierce predators elsewhere. South America had no cats, no dogs, and no bears. What it did have were some marsupial-like mammals called sparasidants. Some of these mammals eventually evolved into fairly large carnivores,

sort of like saber-tooth cats and hyenas, but, you know, different. So with no big dinosaurs as predators and no serious contenders, among the mammals, that left some vacancies, some open niches available in the large carnivore department. Now, just a little aside about the word niche, N-I-C-H-E, niche is how I say it, but someone recently wrote to me and they complained about my pronunciation. And maybe niche sounds wrong to you, too. The thing is, in American biological science, the standard and traditional pronunciation rhymes with which, or ditch or itch. And I'm a biologist by training, and so that's how I learned to say this word. But I realize that in the UK, Australia, and some other regions, the standard pronunciation

is niche, rhyming with leash. And the niche. and the niche version has also become very common in general American English in some non-scientific contexts like marketing and business. But yeah, niche is still the preferred pronunciation among North American biologists when discussing an ecological niche. It's like, I say tomato, you say tomato. I say zebra, you say zebra. I say caesadilla, you say quessadilla.

Which is actually just wrong. The point is that terror birds evolved to fill a bunch of empty ecological niches in South America. From a common ancestor, this group went through an adaptive radiation. It diversified into many species, and those species had a variety of lifestyles. And the rain of the terror birds in South America lasted at least 50 million years, probably more like 60 million. All right, let's talk about what these feathered, monsters actually looked like. Keep in mind that all we have to go on are fossils, bones mostly. But if you search for images of terror birds online, you'll find countless depictions of them.

But just keep in mind, these are all just artist interpretations. Some illustrations are best guesses firmly grounded in paleontology and ornithology. Others are just fanciful and wildly imaginative. Super cool, but maybe not realistic. In any case, there's still a lot we can say about the appearances of terrabirds. I'll go ahead and describe one of the larger terabird species here. We're talking about a bird that stands 10 feet tall, or about 3 meters, and weighs 500 pounds, or 225 kilograms. We can start by picturing an ostrich, or an emu, a big, flightless bird that supports

itself with long, strong legs, and it has a long, S-curved neck. Now, take that bird and beef it up, add mass everywhere. This bird has been drinking protein shakes, maybe taking some steroids. Its body, legs, and neck are thicker, more muscular. And most importantly, the head of a terabird is much, much larger. In the absolute sense, but also relative to the rest of the body. An ostrich has a comparatively tiny, I'd say comically tiny head when you consider the rest of its body. If anything, the Terabird's head is out of proportioned in the other direction.

It seems too large, even for its enormous body. Looking at the Terabird's head from the side, it has a roughly rectangular shape. It's long, front to back, and the bill is deep. It's sort of like the blade of an axe or hatchet. A key feature of the bill is the wicked hook that curves downward at the tip of the upper jaw. very much like the bill of an eagle or falcon. When viewed from the top, the skull forms a wide wedge that is broadest at the rear and tapers continuously toward the front tip. Again, sort of like an axe. And seen from the front, the skull is

surprisingly narrow side to side. The eye sockets are overhung by thick bony extensions. These are called supra orbital ridges. This feature too is something we see in modern raptors. Superorbital ridges have two functions. One, they work like sunshades to protect the eyes while hunting in bright open habitats. And two, they make the bird look angry and kind of badass. The wings on a terror bird are vestigial.

They're just little flaps, kind of like the side view mirrors on a car. And again, the legs are long and thick. And this is really cool. there's actually a fossil of Terrarbird footprints. They belonged to a mid-to-large-sized species that lived in the late Miocene epoch. The bird's tracks were beautifully preserved in lithified mud, mud that has been turned to stone. What those prints confirm is that Terabirds ran and walked on just two main toes,

holding the second toe with its sickle claw elevated off the ground. That's the inner toe. holding it off the ground prevented the curved sickle claw from wearing down or breaking against the terrain, keeping it sharp and deadly. This adaptation is amazingly similar to what we see in the non-avian raptor dinosaurs of the Cretaceous, like Velociraptor and Dinonicus. So that is the basic body plan or silhouette of a typical terror bird. And of course there were differences among species, not the least of which were size differences. Terror birds came in a variety of sizes.

We, not so we and friggin' huge! Or tall, grande and venti, if you prefer. Anyway, the largest, the most friggin' huge species that we know of, was Kalenkin Guillermoi. That bird fits the description I just gave you. That 10 feet tall and up to 500 pounds, Kalenkin was the largest species, overall. And it had the longest skull, about 28 inches or 71 centimeters. So its skull was bigger

than that of a horse. In fact, this species holds the record for having the largest skull for any bird living or extinct, which is just crazy. Kalenken terrorized South America about 15 million years ago. The fossils of this massive bird were first discovered pretty recently, only in 2007. So, Yes, Kalenkin is the largest species so far, but who knows? Maybe there are even larger ones out there waiting to be discovered. Another cool thing is that Kalenkin was not discovered by some Indiana Jones, Alan Grant, Jurassic Park character. Nope, the massive skull of Kalenken was found by a high school student named Guillermo Aguirre Zabala. He found the fossil near his home in Argentina.

Now, maybe you notice something there if you've been. paying close attention. The kid's name was Guillermo, and the scientific name of the terror bird is Kalenken Guillermoi. That's right. Guillermo, the high school student, was honored by scientists when they settled on the bird's name. They named it after him. Pretty cool, huh? Lucky kid. The genus name, Kalenken, has a pretty metal origin. Kalenken, or Kalenkin, was a fearsome spirit or deity in the legends of the indigenous Tejelche people of Patagonia. This spirit was depicted as a gigantic predatory bird capable of carrying off humans.

Pretty awesome. So that is the largest terabird overall. But the heaviest confirmed species discovered is Devincenzia posei. It stood about as tall as Kalenkin, but the largest Devinsenia individuals are estimated to have weighed up to 770 pounds or 350 kilograms.

So those are the biggest tererbirds, but there were plenty of small and medium-sized species too, the wee and not-so-wee. The smallest species discovered so far is Eschatornis Aterodora. It's estimated to have stood just 27 inches or roughly 70 centimeters tall, and it weighed maybe 12 pounds or 5.4 kilograms. So Eschatornis wasn't so scary. It was less like a terror bird and more like a terrier bird, like a cute little doggy.

Now, how about the plumage of terror birds? What colors and patterns did their feathers display? Were they flashy and colorful? Or maybe they were camouflaged with barring and spots? Did these birds sport cool ornaments like crests or waddles? Well, sadly, we just don't know. All we have to work with are fossilized bones and hard parts. So far, no preserved soft parts or pigments from terabirds have been unearthed by paleontologists

or by high school students. So all of the illustrations of these prehistoric birds are based on the speculations of the artists. Similarly, we don't know what terra birds sounded like. We can't describe their vocalizations. But, just for fun, I've taken the song of a living bird, an extant relative of terror birds, and I've slowed it down and lowered the pitch. This isn't scientific at all, but let's pretend this is what a terror bird sounded like. Maybe not such a terrifying sound, but, oh well, it's what I got.

Now, you might be wondering which bird that recording came from. Well, I'll tell you about it in a few minutes. No spoilers for now. As I said earlier, the terror birds went through an explosion of evolutionary diversification beginning roughly 66 million years ago. They had an adaptive radiation. I would have imagined that they started off small, then grew larger and larger over tens of millions of years. But interestingly, that's not how it played out. Gigantism in the family forest Rassadie didn't slowly accumulate. Instead, gigantism evolved right off the bat, early in the Cenozoic era when the family first started to diversify. Meanwhile, some lineages in the family stayed small. At any given time over the

60 million year reign of terror, there existed a mixture of species, some enormous, others relatively diminutive. There were multiple size classes, more or less co-existing. Scientific analyses have suggested that divergence in body size and hunting style were the primary processes that allowed terabird species to coexist in peace and harmony. Co-occurring species within the same ecosystem typically occupied distinct size classes and or hunting modes. And I'll talk a little bit more about that in a moment. At the time I'm recording this episode, there are about 17 confirmed terabird species that have been discovered. Some paleontologists have estimated that overall there were 20 to 25 species living at one time or another across 60 million years. So that gives us a

sense of the overall diversity for the family forest racity. Maybe that's an underestimate, but that's what we have. And that diversity was found primarily in South America. most terabird fossils have been found in Argentina, Uruguay, and Brazil. Now, a little side note about the name of this family, Foris Rassidy. Again, the spelling is P-H-O-R-U-S-R-H-A-C-I-D-A-E. The family name comes from the genus that was given to the first terabird ever discovered, Foris Rikos. And that translates from Greek to mean wrinkle-bearer or rag-bearer.

Or maybe scar bearer. It's a little uncertain. So that's kind of weird, right? Rinkle bearer, scar bearer, one who has wrinkles, which every day is becoming a better description for me. The reason that the first terabird that was discovered ended up with such an odd name comes down to a case of mistaken identity. When the famous Argentine paleontologist Florentino Amagino first discovered the original specimen in Patagonia in 1887, he didn't have a complete skeleton or even a full skull. He had only a fragment of the lower jaw. And because that bone lacked teeth, and it had this highly textured, wrinkly bone surface,

Amagino mistakenly assumed it belonged to one of those Xenarthrin mammals, like a giant ground sloth or something. It was only some years later when Amagino realized that the wrinkle-bearer was actually a giant bird, not a mammal. Now let's look at how terror birds hunted and what they ate. One factor that influenced the hunting lifestyle of a given species was its habitat. Did it live in the forest or out on the open grasslands or along the interface between these two ecosystems? We can think of terror bird species being divided into three major ecological roles.

Generalist predators, pursuit predators, and ambush predators. hunting strategies and diets varied between these groups, and therefore so did their physical characteristics. The smallest terror birds, the terrier birds, tended to be generalist predators. They preyed on invertebrates, small reptiles like snakes and lizards, birds, rodents, and small marsupials. As generalists, small terror birds probably could be found in a variety of habitats. Then we have the pursuit predators, the ones that chased down their prey. The word biologists use for animals adapted for running is cursorial, C-U-R-S-O-R-I-A-L. Cursorial animals have long, slender leg bones.

Examples of modern critters in this category include horses, antelope, cheetahs, and ostriches. Medium-sized terror birds tended to be cursorial or. pursuit predators. We're talking species standing between four and five feet tall or 1.2 to 1.5 meters. They lived in grasslands and open woodlands. Their prey included large flightless birds related to modern-day reas, as well as medium-sized mammals like the deer-like ungulates called Lytopterns. Some of the larger terabird species were also pursued predators, species like Foris Rekos and Titanis. They would be able to run down even larger mammalian prey.

Estimated running speeds for cursorial terror birds in general were 30 to 45 miles per hour, or 50 to 70 kilometers per hour. And think about this, that is the maximum speed of a wild horse running today. There's no way you were going to outrun a terror bird. If you watch some of these documentaries about prehistoric animals on Netflix or the BBC or wherever, sometimes there's a scene with a pack of terror birds cooperating to take down large prey on the grasslands, sort of like modern-day lions or wolves. It would be pretty cool if some terabirds were cooperative hunters like that.

And it certainly seems possible, but I think it's mostly speculation. I'm not sure there's any hard evidence for that behavior. Okay, so we've covered generalist and pursuit predators. That leaves the ambush predators. These species were massive and heavily built. Kalenkin and Devincenzia, who we talked about earlier, are in this category. Instead of being cursorial, biologists use the word Graviportal for these Hulk-like bruisers. Graviportal describes large, heavy land animals that have physical body supports and limbs adapted to carry their immense weight. They have column-like limbs.

Examples include the sauropod dinosaurs, as well as elephants and giant tortoises. The leg bones of the largest terrobirds were thick, heavy, and broad relative to their length, sort of column-like. Such legs were suited for short-burst acceleration from cover, for high load-bearing capacity, and for providing a stable base to strike or grapple with heavy prey. Paleontologists think that ambush predators lived in the forest, where they could lurk in the leafy shadows waiting for hapless prey to walk by. They targeted large South American ungulates,

the ones that weighed over 220 pounds or 100 kilograms. And they also hunted juvenile megafauna, such as young giant ground sloths, and rhino-like mammals called toxidants and astrapheres. And if humans had been around, we too would probably have been on the menu for these giant terror birds. As I mentioned, it was possible for multiple terabird species to coexist in the same ecosystem, maybe four or five species.

Because they hunted differently and ate different prey, they weren't in direct competition with each other. Biologists call this phenomenon ecological niche differentiation or niche partitioning, or niche partitioning, if you prefer. I've talked about this in other podcast episodes. Okay, looking a little closer at the anatomy related to foraging, to hunting. Many species may have used their axe-like beak and talons to attack in a similar way. Terra bird skulls were rigid and fused, which is not the way most bird skulls are set up. Terabird skulls were able to absorb the shock from up-and-down impacts.

But at the same time, they were relatively vulnerable to side-to-side. twisting. So it seems terror birds couldn't really shake or struggle with large animals without risking potential jaw fractures. Instead, they relied on rapid vertical strikes, driving the sharp hooked tip of their bill downward

like a pickaxe into vital areas before pulling back. Smaller prey animals were just swallowed whole, which is pretty brutal, but larger victims were worn down through these repeated, targeted blows. So the technique was attack and retreat, attack and retreat until the prey animal collapsed. This deadly striking power of the bill was driven by a spring-like neck and helped out with some specialized feet.

A terabird's neck was divided into three functional sections, with powerful muscle levers and stretchy elastic ligaments. Strong lower neck muscles snapped the heavy head downward with maximum speed, while the elastic ligaments immediately recoiled the head back up into starting position ready for the next blow. And to keep its victim from escaping, a terabird used that sickle claw to step on and pin the struggling prey firmly to the ground, while delivering precision strikes with the bill. A lot of what I just described about the skull and neck anatomy came from a study on the fossils of a species called Andogalornis stulatai. That species was about 4.6 feet or 1.4 meters tall and weighed 90 pounds or about 40 kilograms. The study was conducted by Claudia Tambusi and her colleagues, and it was published in 2012 in the journal PLOS 1.

If the terror birds had a golden age, it was during the Miocene epic, roughly 23 to 5 million years ago. That is when we see the highest species diversity and the most extreme, gigantism. But the good times couldn't last forever, could they? The party had to end eventually. Following the end of the Miocene, global cooling, forest contraction, and expanding dry grasslands began to reduce the number of terabird species that were running around. And then something truly amazing happened. About three million years ago, during the Pliocene epic, South America suddenly stopped being an island. Well, suddenly in the geological sense.

Because North and South America became connected by that little ribbon of land called the Isthmus of Panama. There's that word again. If-is-thmus. Good times. I always struggle with that one. Isthmus. I-isth-mus.

Anyway, the isolation of South America, which had lasted for over- for 60 million years came to an abrupt end. And oh boy, were the animals ready for it. I can imagine the North American animals all lined up on their side, waiting impatiently as the isthmus was slowly rising out of the ocean. And the South American animals lined up too, facing north. When the land bridge finally formed, all hell broke loose and critters of every sort stampeded across in both directions. And so began the great American. Biotic Interchange, one of the most fascinating biogeographic events we know of, the Great American

Biotic Interchange. The animals and plants of the two continents came together and the world was never the same. The Great American Biotic Interchange, or Gabby, included the immigration into South America of North American rodents, camels, tapirs, deer, horses, big cats, dogs, mastelids, raccoons, and bears. In the reverse direction, going from south to North America, the migration included giant ground sloths, gliptodonts, capybaras, some other weird mammals, and yes, terror birds. Well, at least one anyway. Its name was Titanic. No, no, not Titanic, not the ship, Titanis. Its full scientific name is Titanus Wallerai, and it was the only terror bird species known to have lived in North America.

It stood between 5 and 7 feet tall, or 1.5 and 2.1 meters. And amazingly, it weighed up to 660 pounds, or 300 kilograms. That is a beefy bird. Fossil remains of Titanis have been unearthed in Florida, Texas, and California, showing that this giant bird roamed subtropical savannas, grasslands, and mixed woodland environments. It hunted a wide range of North American mammals, including ancient horses, capybaras, tapers, and gliptodonts, which are those armored relatives of armadillos that have these big dome-like shells. Now here's an interesting thing. Unlike its South American ancestors

that evolved in relative isolation, Titanus coexisted alongside formidable mammalian carnivores in North America, including saber-toothed cats, wolf-like canids, and gargantuan short-faced bears. Titanus was able to hold its own for millions of years, even with all those predators around. Early theories suggested that competition with such mammalian predators or interactions with human hunters drove Titanus to extinction. But more recent fossil dating confirms this bird died out around 1.8 to 2 million years ago in the early Pleistocene. And that was well before any humans arrived on the scene. So it seems the eventual disappearance of Titanus was primarily driven by major global climate shifts and habitat changes as the Ice Age kicked into full swing.

Our understanding of what happened to the rest of the terrobirds, the ones down in South America, has also changed. Older hypotheses suggested that invading mammalian carnivores from North America wiped out all the terabirds following Gabby, the Great American Biotic Interchange. But more recent evidence indicates that climate-driven habitat loss was the primary driver of their decline. It turns out that terabirds were already disappearing well before most of those large placental predators arrived. As these environmental pressures occurred, the largest terabird species died out first, during the late Pleiocene and early Pleistocene epics. But some of the smaller terabirds were more resilient, what with their generalist hunting strategies

and ability to use a variety of habitats. Compact species like Silopterus and Eschatornis carried on, living as mid-ranking predators, targeting smaller prey across diverse savanna and woodland habitats. By avoiding direct competition with large mammalian carnivores, these smaller terabirds survived much longer than scientists once believed. They lived late into the Pleistocene epic, roughly 25,000 years ago. So even the small, final terabird species in South America seemed to have died out before they ever rubbed shoulders with good old homo sapiens.

After terrorizing the creatures of South America for over 60 million years, and North America too, for a little while, the glory days of the terror birds came to their end. The comeback... Don't call it a comeback! I mean, the resurgence of the bipedal predatory dinosaurs had run its course, so to speak. But dig this! There are still a couple birds alive today that are close cousins to the terror birds.

These are the seriamas of the terrar birds. the family Kariamadi. They live in South America. This family is in the order Kariama Formis, the same order that the Terribird family belongs to. There are just two species, the red-legged Sariama and the black-legged Sariama. And Sariama is spelled S-E-R-I-E-M-A. These are tall, long-legged cursorial birds. Because of this close evolutionary connection, the behaviors we see in living Sariamas, such as using their feet to hold down prey or slamming captured animals to subdue them, those behaviors give paleontologists some insight into how Terrabirds might have lived and hunted. Sariamas and Terribirds share several key predatory adaptations.

Most notably are their legs and specialized foot structure. Both feature a modified second toe with that enlarged, curved sickle claw that is kept raised off the ground to avoid wear and tear. So Sariamas today are like small living echoes of their giant relatives. They aren't terror birds, but they're the closest thing we have. And remember that bird recording I used earlier, the one I slowed and pitched down? That was from a red-legged Sariama. Here's that same recording at regular speed. I still haven't seen either Sariama species, but after doing this episode, especially now, I really want to see one. Hopefully someday. So that is an overview of the terror birds, what they looked like and a little bit about how they lived. They are, or were,

such cool birds, and the story of their evolution is amazing. It just shows you that you never know what direction evolution is going to take in a particular lineage. It's unpredictable. Because, sure, we call this the age of mammals, but the rise of terror birds shows us how it wasn't inevitable that mammals would come to dominate the world. The terror bird story reminds us that when the ecological stage is empty, when there are niches to fill, evolution will find someone to step out onto it. And sometimes that someone has feathers. That does it for episode 139. If you were already a fan of terror birds, I hope this episode was satisfying and that you learned a little something new. And if you weren't already a terror bird enthusiast, I hope you are now.

I'll put some links to some YouTube videos about terror birds in the show notes, if you're interested. Unlike the Terrorbirds, the Science of Birds podcast has not gone extinct, and that is largely because of my supporters on Patreon. Their monthly and annual contributions allow me to take the time to make these episodes and share them with listeners all around the world in just about every country on the planet. So a massive thank you to all my Patreon supporters. And I want to welcome the newest patrons, Carla, Saiwei Oli, Alina, Sue, and Larry Lake. Welcome and thank you so much for the generous help.

If you, my friend, are thinking about becoming a patron, you can check. out my Patreon page over at patreon.com slash science of birds, and there's also a link in your podcast app in the show notes. If you have something you'd like to share with me otherwise, please go ahead and shoot me an email. Perhaps you have a comment about the podcast, or you want to take issue with how I pronounce a particular word, or maybe you're a high school student and you want to tell me about the gigantic fossil skull you just found. In any case, my email address is Ivan at scienceofbirds.com. Again, this is episode 139. You can check out the show notes for the episode in your app

or on the Science of Birds website, Scienceof Birds.com. As always, I'm Ivan Philipson, and true fact about me, for as long as I can remember, I have this weird compulsion or need to be the person who claps last. And what I mean is, for example, I was recently at a stand-up comedy show here in Portland, and when there was a round of applause, I did what I pretty much always do, I kept clapping until I was the one who got in the last couple of claps.

And I always make sure my final claps are good and loud. I don't know why I started doing this or why I keep doing it. It's totally ridiculous. I mean, I guess it doesn't hurt anybody, right? But I just hope I'm never in the same room with someone else who also has this strange habit. Because then we'll have a clap battle and it could go on for hours. Who knows? He who claps last, claps best. That's the saying, right? Anyway, that's me. Thanks for listening. I wish you all the best and all the birds.