The Science of Birds - How Birds Breathe: The Avian Respiratory System

Episode Date: November 18, 2025

👕 Bird Merch —  Get yourself some bird shirts!~~~This is Episode 125. Host Ivan Phillipsen takes listeners inside the amazing respiratory system of birds. He starts by grounding the topic in familiar territory—how mammal lungs work—before revealing how different the avian system really is.The episode walks through the unique division of labor between birds’ small, rigid lungs and their large air sacs, and explains the elegant, one-way flow of air that keeps oxygen constantly moving across gas exchange surfaces.The episode also looks back in time, exploring how this respiratory design first evolved. Listeners will come away with a deeper appreciation of what’s happening inside every bird with each breath.Link to this episode on the Science of Birds websiteBird Merch - See the NEW shirt designs!Support the show

I'd like you to do something. Just take a nice, deep breath. Inhale and exhale. Feels kind of nice, doesn't it? Of course, breathing is essential for keeping your body alive. The anatomy and physiology involved in the process are complex and can seem almost miraculous. You probably have a good idea of how it all works. But most of the time, we aren't really conscious of our own breathing.

We just take it for granted, right? Now, if you had to guess how many breaths you take per day, what would you say? What would that number be? It turns out the average adult human takes something like 20,000 to 25,000 breaths per day. That's kind of a lot. Now, picture a small songbird, something cute like an American goldfinch, or maybe a common chaffinch if you're in Europe, or a superb fairy wren if you're in Australia. picture that bird resting perched on a branch its fluffy little body pulses as it breathes expanding and contracting imagine the tiny puff of hot air escaping the nostrils with each breath and if we're being honest that breath is probably stinky i mean lord knows what that bird has been eating or the last time it used mouthwash in any case that bird probably breathes about twice as many times as you do in a day an average songbird takes

between 40,000 and 90,000 breaths per day. And smaller species with really high metabolisms, like hummingbirds, may breathe 200,000 to 400,000 times per day. Crazy. But it's really the way that birds breathe that's most interesting. How they breathe is fundamentally different from what's going on inside of you and me and unique among all air-breathing animals. 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 episode, which is number 125, is all about the avian respiratory system. After five years of making this podcast, I'm finally getting to the respiratory system. I've already done episodes focusing on other anatomical subjects like feathers, the skeleton, the brain, and the digestive system. And there are still other topics in this category, the reproductive system, the circulatory system, and so on. We'll get to those in future episodes. But today, it's all about those sexy little bird lungs and air sacks.

So, as I said, among air-breathing animals, the avian respiratory system is one of a kind. It's a masterpiece of biological engineering, supercharged for maximum efficiency. But this system is not a recent avian innovation. As we'll explore today, the fossil record tells us that the origins of this system go way, way back, before the first bird ever existed. All right, well, let's take a deep bird. breath and dive in. First, let's look at the big picture.

Let's think about why birds and all other animals need to breathe. And then we'll look at the way humans and other mammals breathe. Breathing is about gases going in and out of the body. It's how animals bring in the oxygen their cells need and get rid of weight. waste, which is carbon dioxide. Every cell in the body uses oxygen to burn fuels from food. And by burning, I mean chemical reactions that release energy from food in a controlled way. That energy is then used to power everything the body does, moving muscles, making new cells, keeping warm, using the brain to think about things like birds or astrophysics, and so on.

But the same chemical reactions that use oxygen to produce energy also produce carbon dioxide as a waste product. These gases need to be in balance in the cells. Too little oxygen and the cells can't make enough energy. Too much carbon dioxide and the blood becomes acidic and dangerous. The lungs are the place where this exchange of gases happens. It's in the lungs where gases diffuse into or out of the blood. When you inhale, fresh air, rich in oxygen enters the lungs. Oxygen moves into the blood, which carries it to every part of the body.

At the same time, carbon dioxide from the cells is carried back in the blood to the lungs. When you exhale, that carbon dioxide is pushed out of the body. So the function of breathing is to keep this oxygen-in carbon dioxide out cycle going so that cells can keep running their microscopic energy factories, safely, and, efficiently. Okay, so how does this work in humans and other mammals? The mammalian respiratory system is basically a branching series of tubes that looks sort of like an upside-down tree. The tubes are like branches that split into smaller and smaller branches, and then they terminate in leaves that are actually millions of tiny air sacs.

Air comes in through the nose or mouth, goes down the tree, trachea, or the windpipe, and that is like the trunk of our upside-down tree. And then the tracheas splits into two main branches called bronchae, one for each lung. You know, I would bet good money that these words, branches and bronchae, or singular branch and bronchus, are related. I would have guessed that they share a common origin, etymologically, in ancient Greek or Latin. But nope, not at all. I would lose a lot of money on that bet. Branch and bronchus look and sounds similar,

and in the case of the lungs, we can even link them through this helpful analogy, but their similarity is only a coincidence. It's kind of like me being named Ivan, and that's kind of like similar to the word avian. It's just a coincidence, I guess. Ah, the mysteries of the universe. Anyway, inside each lung,

these tubes keep dividing into smaller bronchite, and then into very fine bronchioles, like the twigs at the outermost edge of a tree. At the tips are those tiny air sacs, the alveoli. Each of these sacks is surrounded by an intricate web of capillaries, which, of course, are very small blood vessels. The walls of the alveoli and capillaries are extremely thin, so gases like oxygen and carbon dioxide can easily move across those walls. When a human or other mammal inhales, the diaphragm, which is a sheet of muscle under the lungs,

contracts and moves down, and the muscles between the ribs lift the rib cage a bit. All of this makes more space in the chest, and that lowers the air pressure inside the lungs. So, air flows in. In the alveoli, those tiny sacks, oxygen from the air moves into the blood, and carbon dioxide from the blood moves into the air sacs. When you exhale, the diaphragm relaxes and moves up. The ribcage settles down, the space in the chest gets smaller, and so air is pushed out. And with it goes the carbon dioxide.

The circulatory system then delivers the oxygen-rich blood to all the tissues and brings carbon dioxide-rich blood back to the lungs, keeping the gas exchange cycle going around and around forever and ever, until you die. So in this mammalian respiratory system, the lungs act like a bellows, performing the pumping action to bring air in and out. You know, a bellows, the thing that sounds plural but is actually singular. Surely kids today are all familiar with household tools like the bellows, an instrument or machine that by alternate expansion and contraction draws in air through a valve orifice and expels it through a tube,

the thing you use to blow air into a fire. You know. Well, an important thing about this mammalian system is that with every breath, fresh, oxygenated air coming in is immediately mixed with stale oxygen-poor air that's already in the lungs. And this limits the efficiency of gas exchange. I mean, it works well enough, but as we'll see, there's another system that's more efficient. Because in a moment, we're going to be contrasting the way the respiratory system works in humans and other mammals, to the system in birds. But before we do that,

for the sake of being thorough here, I should say that reptiles, like lizards and snakes, breathe with simple lungs that work more like balloons than like the complex spongy lungs of mammals. And reptiles don't have a diaphragm muscle like mammals. Amphibians like frogs and salamanders are even more different. They have even simpler lungs,

and many of them also absorb a lot of oxygen, just through their skin. Amphibians sort of gulp air into their lungs using movements of the throat rather than expanding a chest cage like mammals or reptiles. Now alligators and crocodiles, critters in the order crocodilia, have their own way of breathing. But we'll talk about that a little later. Now it's time to look at the physical structure of the avian respiratory system. Okie-dokey, let's check out the various parts of a bird's respiratory system. Here's a key takeaway to remember. The core design principle of the avian system is the division of labor between two parts.

One part acts as the pump. The other is where gas exchange happens. That's in contrast to mammals where the lungs do it all. In birds, the lungs are the part of the system where gas exchange happens. A bird's lungs are surprisingly small. They're wedge-shaped, compact, and rigid little organs that don't really expand or contract all that much. When a bird breathes, the lungs change in volume by only about 1.4%. Compare that to the average human's lungs, where these organs expand and contract by about 20% during a relaxed breath.

Bird lungs are in the dorsal part of the body cavity. In other words, towards the spinal column, the top. And they're actually attached to the spine and ribs. The lungs are stuck firmly in place. So in birds, the lungs are entirely devoted to this single task of gas exchange. They contain thousands of parallel looping passages called parabronkite, where oxygen is transferred to the blood. Parabranchi are to birds what the alveoli, those tiny sacks in our lungs, are to mammals. Parabronkai and alveoli are the terminal gas exchange units.

Instead of being a dead-end sack, a parabronchus is actually a tiny tube. The singular form of parabronkai is parabronkis. This tube is about the width of a strand of spaghetti, and air is flowing continually, through each para bronchus. But at the microscopic level, there are little nooks and crannies, little air capillaries, in the walls of a parabronchus. And it's in those microscopic spaces where air comes into close contact with blood vessels. That is where the magic happens. Oxygen and carbon dioxide are exchanged between the air and the blood. If you were to add up the surface area of those countless nooks and crannies in a bird's lungs, you'd end up with a vast,

surface over which gases can be exchanged. That surface is about 15% larger in a bird when compared to the gas exchange surface in a mammal of similar size. I want to take a moment to let you know that I just released a bunch of new designs on bird merch. That's my online store at birdmerch.com where I sell bird and birding themed shirts. I've been working on these new designs for the last couple of months, and I'm jazzed to finally release them into the wild. They feature birds like the Greater Sage Grouse, Common Yellow Throat, Sanderlings, Piedbilt Grebe, and more. Also, when I first launched bird merch, a lot of people kept asking if I was going to offer shirts in women's styles. So by popular demand, I'm happy to say that I've

now got some great shirts for the ladies. For now, I can only ship to customers in the U.S. I'm working on being able to sell in Canada, the UK, and more, and I have not forgotten about all my overseas friends. Anyway, the holidays are just around the corner, so I hope you'll skip on over to birdmerch.com and pick up some shirts as gifts or just because. Every bird merch purchase helps support me and the Science of Birds podcast. All righty, let's get back to the show. Okay, so that was the lungs. That's the first part of the system. The second part is the pump. In birds, the job of pulling and pushing air into and out of the system is taken care of by the air sacs. These air sacs are nothing like the tiny alveoli we were talking about in the mammalian lung.

The air sacs of birds are much, much larger. Their thin-walled, balloon-like structures found throughout the bird's body. In fact, about 15% of a bird's total body volume is taken up by these air sacks. They work like a bellows to actively pump air through the lungs, which don't really move much. The air sacks themselves are poorly supplied with blood, so they do not play a role in gas exchange, at least not directly. Most birds have nine air sacks, but depending on the type of bird, there can be between seven and twelve. Most of the sacks are paired, symmetrically on the left and right side of the bird's body.

I'm not going to go into describing all of the air sacks, but I just want you to know a key distinction among them. Some of the air sacks in the body cavity are closer to the bird's head. So those are called the anterior air sacks. And the ones towards the back end of the bird are called the posterior sacks. You can picture these structures as thin-walled balloons. They take up a lot of space inside a bird. And you know how spooky clowns sometimes try to entertain children by making things out of long, skinny balloons?

Well, in birds, there are skinny air sacks that actually extend into some of the bones. This is called skeletal pneumaticity. Now, there's a word to impress your friends with, pneumaticity. It's got one of those silent peas. Numa is spelled P-N-E-E. So in skeletal numinicity, one example is where there are cervical air sacs that pneumatize some of the cervical vertebrae and ribs. This is pretty wild, right? Think about that. Some of the hollow bones of birds are invaded by extensions of the respiratory system. But my understanding is that those

particular air sacs, the ones invading the bones, do not work as part of the pump or the bellows. but I'll come back to skeletal pneumaticity again in a moment. Now, remember that mammals have a diaphragm, that broad, flat muscle that moves up and down to help the lungs contract and expand. Birds, however, do not have a diaphragm. Instead, a bird uses its rib and abdominal muscles to contract and expand its body cavity, and therefore contract and expand its air sacs. We've covered the basic blueprint of the avian respiratory system. Now it's time to walk through how it all works together.

Remember that the avian system operates in a way that's fundamentally different from our own and those of any other living air-breathing vertebrate. There's a complete separation of the jobs of pumping air and exchanging gases. As we go through the steps that occur during breathing, keep these two important facts in mind. One, it takes two full cycles of inhalation and exhalation for a single breath, a single packet of air to travel through the entire system. In humans, there's only one cycle.

The second important fact is, in birds, there's a continuous one-way flow of fresh oxygen-rich air across the gas exchange surfaces. We call this unidirectional airflow, meaning it moves in one direction. Not to be confused with international pop sensation one direction, the English-Irish boy band formed in 2010, where we got Harry Stiles and all of that. All right, so two important facts.

One, it takes two full cycles for air to move through the system, and the other fact is that there's this continuous one-way flow of air through the system. All right, we're looking at a bird. And just for the heck of it, let me hit the random bird selector button here to see which species we can imagine. Oh, sweet. We got the blue-banded toucanette, aola carinkus, Cyrilicinctus. This is a lovely green bird with a blue band across the breast, blue eye shadow, and a large blue-gray-grey bill. It's got a little white throat and a rusty red rump patch. Its range is pretty small.

It lives in just Peru and Bolivia, in a small area, and it hangs out in montane subtropical forests and cloud forests. Okay, so our blue-banded toucanette has just eaten a bunch of fruit, and now it's relaxing on a tree branch, feeling good about life. As it breathes, its body expands and contracts. Let's follow one packet of air through this bird's respiratory system. Step one is the first inhalation. Air enters through the nostrils, then passes into the trachea, aka the windpipe.

The trachea splits into two bronchae. And that point, that splitting point, is where the syrinx is, S-Y-R-I-N-X. remember that the syrinx is the organ that makes vocal sounds in birds. Our packet of air travels into the bronch eye, which then enter the lungs. But the air doesn't stop in the lungs. It keeps moving, passing through the lungs, and ending up in the posterior air sacs. These sacks are behind the lungs, in the direction of the tail toward the bird's lower belly. During this step, the first inhalation, the bird expanded its body cavity and the air sacs

increased in volume. They expanded. That is the pumping action that pulls air into the sacks. Step two is the first exhalation. Now the bird's body cavity and air sacs contract. They get smaller. This forces our packet of air back into the lungs through a separate tube. Now that the air is in the lungs, gas exchange can actually happen, in the little strands of spaghetti, the parabronkai. into the blood, carbon dioxide out. Step three is the second inhalation. The blue-banded tucanette expands its body cavity and air sacks a second time. This action pulls the air forward into the anterior air sacs.

These are positioned a little closer to the bird's head, but still inside the body cavity, kind of around the breast area. The air that moves from the lungs into the anterior air sacs is now stale. It's been depleted of oxygen and it's got a lot of carbon dioxide in it. The final step is step four. This is the second exhalation. The toucanet contracts its body, the air sacs contract, and the stale air is pushed up the trachea and out of the nostrils.

So there you go. Two rounds of inhalation and exhalation to move a single packet of air all the way through the system. The blue-banded toucanette just got some much-needed. oxygen to help power its body for whatever mischief it has planned for the rest of the day. Now, I hope that made sense. It's a challenge to explain this process using only words without showing you a diagram or animation. During every inhalation, just picture all of the air sacks growing larger, expanding in volume. Air moves into, is sucked into a sack when the sac expands. And during every exhalation, all the air sacs contract. Air is squeezed out of each

air sac during this step, pushing the air from one area to another. Now, this is all lovely and great, but maybe it sounds kind of similar to the in and out system in mammal lungs. But it's not because air in the avian respiratory system travels in kind of a loop, moving in only one direction. As we said, it's unidirectional. In mammals, air moves in and out along the same path in what scientists call a tidal mechanism, like the tide moving in and out. The bird system is more efficient, because while that first packet is moving through the loop, there's another one just behind it, a second packet that entered during the second inhalation. The first packet moves into the anterior air sacs in that step, while the second packet moves into the posterior air sacs.

This setup is super efficient because there's a constant supply of fresh oxygen-rich air moving across the gas exchange surface of the lungs. I can imagine a bird perched with its eyes closed and it's trying to meditate. It's got headphones on listening to a meditation teacher who says, Now just relax and concentrate on the simple act of breathing. Feel the air moving through you. For example, during the first expiratory cycle, from your posterior air sacs into the parabronkite of your lungs via the medial dorsal secondary bronchai,

and then during the second inspiratory cycle onward into your anterior air sacs. Just follow the breath. It's not complicated. The super-efficient system of unidirectional airflow surely evolved as an adaptation for powered flight in birds, right? Like core features of the avian respiratory system must have evolved in response to the needs for lots of energy during flight. False. As I hinted at earlier, this system, at least its core features anyway, evolved way before flight, before there was anything on earth that we would call a bird.

The feature of unidirectional airflow seems to have been a deep ancient trait present in the earliest archosaurs, or even before then. So we're talking maybe 250 million years ago. That was before there were even dinosaurs. Arcasors are the ancestors of dinosaurs, pterosaurs, and crocodilians. Crocodilians, like alligators and crocodiles, are the closest living relatives of birds. Like their Arcosaur ancestors, crocodilians also have unidirectional airflow. However, the anatomy is different from what we find in birds. And maybe that's not surprising because these two groups have been evolving along different paths for about 250 million years.

So unidirectional flow has been around for at least that long. Much later, the ancient Argosaur model got an upgrade, with rigid lungs and specialized air sacks and the division of labor. That seems to have happened within the theropod dinosaur lineage. And when you hear theropod dinosaur, you want to think Tyrannosaurus Rex, Velociraptors, and yes, birds. But again, these features evolved before flight, before birds. That means this highly efficient respiratory system didn't evolve in response to the needs of flight. Instead, it was a lucky pre-adaptation that made flight more practical down the line. Organs like lungs don't leave behind fossils, for the most part. So paleontologists have had to use indirect evidence to

piece all of this together, and that evidence comes from the fossilized bones of dinosaurs and their ancestors. One of the most powerful bits of evidence comes from a feature called post-cranial skeletal pneumaticity in dinosaurs. We talked about pneumaticity earlier. This is the presence of air-filled cavities within bones other than the skull. That's why it's called post-cranial. The cavities were created by the invasion of the bones by outgrowths of the air sacs, just like what we see in birds.

These invasions leave behind telltale holes on the bone surface called pneumatic feramina, or pheromina. Remarkably, the locations of these pheramina in the vertebrae of theropod dinosaurs are virtually identical to those in modern birds. For example, there's a fossil of this large carnivorous theropod from Madagascar called Majongotholus atopis. It's got pneumatic pheramina, those little holes perforating the vertebrae all along its backbone. But now we should ask the question, what is the function of pneumatized bones?

Why do the air sacks invade the hollow bones of theropod dinosaurs and birds? I don't think scientists have settled on a single explanation yet, but there are several hypotheses. For large-bodied dinosaurs, it could be that having a pneumatized skeleton was a way to reduce mass. A lighter skeleton would take less energy to grow and maintain, and maybe it would make the animal more maneuverable and nimble on its toes. And, yeah, of course, such bones with their lower mass would make it easier for flight to evolve. Another hypothesis is that rapid airflow associated with the air sacs invading the skeleton might have provided an effective way for large active animals to get rid of excess body heat,

especially if they possessed insulating structures like feathers. But notice that these explanations have nothing to do with breathing, with respiration, Scientists don't think that the air sacks in theropod and bird bones evolved to help with respiration. The second key piece of evidence comes from the structure of the rib cage, which reveals the nature of the lungs it housed. By comparing the ribcages of theropods and birds, it's clear that the theropod rib cage was constructed to house a rigid, non-expanding lung that was fixed in place. So, based on the fossil evidence, we can say that ancient theropods had a respiratory system a lot like that of modern birds. One big question then is, if it wasn't for flight, why did this system evolve in the first place?

The answer might have to do with the amount of oxygen in the atmosphere. About 250 million years ago, Earth went through its biggest global extinction event ever, the Permian Triassic extinction, also known as the Great Dying. For the first few million years after the devastating extinction event, oxygen levels in the air were a lot lower. Some scientists hypothesize that the superior lung design of the earliest dinosaurs gave them a critical survival advantage in this hypoxic world, hypoxic meaning low oxygen. Their lungs allowed them to ring as much oxygen as possible. out of each breath, and that allowed them to thrive while other groups struggled. Dinosaurs then diversified and came to dominate the planet starting around 200 million

years ago. The highly efficient system that theropods eventually developed allowed for a much higher and more sustained metabolic rate than was possible for other reptiles. This high aerobic capacity was probably essential for supporting an active, predatory lifestyle, the lifestyle of velociraptors and whatnot. I just want to reiterate that this is still a hypothesis. We don't know for sure that the respiratory system of early dinosaurs or eventually theropods was a key to their success in a low-oxygen world. But it's certainly an intriguing idea. I think we can say, with some confidence, that the

respiratory system of birds is a key to their success. It gives them some superpowers. They inherited their supercharged system from their theropod ancestors. It's structurally the most complex and functionally the most efficient gas exchanger of all air-breathing vertebrates. And speaking of other air-breathing vertebrates, what about bats? I mean, isn't that the first question most of us think of when we wake up every day? What about bats? Yeah, what about those fuzzy little night flappers? They're cool and they're cute, but they're also mammals, right? And as mammals, their respiratory systems shouldn't be as efficient as those of birds. And yet they fly! Therefore, it's obvious that mammalian lungs can provide enough oxygen for flight. And that's because the respiratory

systems of bats are specially adapted for flight. If you take a bat and a non-flying mammal of the same size, like a mouse, and you sit them side by side, and you put funny little hats on them, because why not, you'd see that the respiratory systems of the bat and the mouse have the same overall structure, just like yours and mine. But the bat's lungs are proportionally larger than they have a larger surface area for gas exchange, and they have a denser network of capillaries. So through their evolution, bats have taken the basic mammalian respiratory model and pushed it to the limits of efficiency. But even so, bats cannot fly as fast or as far as most birds. Many bird species fly thousands or tens of thousands of miles every year during

migration, and some of them, like the bar-headed goose, can fly at really high altitudes, up to four and a half miles or seven kilometers. Oxygen levels way up there are so low that you or I would pass out in like a minute. But those birds can just keep flying hard, getting all the oxygen they need. I should also mention that birds today use the air sacks in their respiratory system for more than just breathing. The sacks have been co-opted by evolution for use in things like thermoregulation, buoyancy control during diving, impact cushioning, and protection of the organs. Okay, so let's do one big summary here. Birds have these small, rigid lungs tucked up against

the spine that never really change size. They're packed with tiny tubular para-branchi, which is where gas exchange happens. The pumping action is outsourced to those big, thin-walled air sacs, both anterior and posterior, some of which even invade the bones as part of skeletal pneumaticity. Instead of a diaphragm, birds use their rib and abdominal muscles to expand and compress the sacs, pulling air through the system in a one-way loop that takes two full inhalation exhalation cycles for a single packet of air to travel all the way through. This keeps oxygen-rich air flowing across the gas exchange surfaces continuously,

and that's very different from our title, In-N-Out, Mammal Lungs, where fresh air is always diluted by stale air. This unidirectional airflow and division of labor between rigid lungs and pumping sacks seems to have deep roots with the early archosaurs and theropod dinosaurs, possibly giving those critters an evolutionary edge in the low, oxygen world after the Permian triassic extinction. And this system might have supported the active lifestyles of predatory dynos long before any birds existed. Modern birds have inherited and refined that ancestral hardware into the most efficient vertebrate gas exchange system that we know of,

one that powers long-distance migrations, high-altitude flight, and generally turbocharged metabolisms. So the next time you see a bird perching or resting, watch for signs of it breathing. Now you have a better understanding of the amazing process that's going on inside with each breath, between 40,000 and 400,000 times every day. Cool. We've covered another key topic in the anatomy of birds. Pretty neat stuff, huh? I hope you enjoyed the episode. Understanding the way air moves through a bird's respiratory system isn't all that intuitive. So I'd recommend looking up some diagrams showing the steps that walk through the two inhalation

exhalation cycles. It helps to have a visual aid like that. This episode, like everyone before it, was made possible largely because of the amazing support I get from my Patreon community. Members of my community make monthly contributions that cover my podcast. expenses and help me pay my bills so I can keep making more episodes. So thank you to all my wonderful patrons and a big welcome to the newest members, Glenn Belongi, Tsai Wei Oli, Kelly Sargent, Marcia, and Andre G.

Sorry for any mispronunciations, but thank you guys so much for stepping in to support the show. You're amazing. If you're interested, you can learn more about my Patreon community by clicking the support the show link in the show notes. Or you can simply go to patreon.com slash science of birds. You can also shoot me an email if you have something you'd like to share, perhaps your favorite spaghetti recipe or your thoughts on bats. In any case, my email address is Ivan at scienceofbirds.com. This is episode 125. You can check out the show notes on the Science of Birds website, Scienceofbirds.com. And just a reminder, if you like birds,

and you wear t-shirts, you should check out my online store, BirdMurch. Just go to birdmerch.com and get yourself some shirts. I'm Ivan Philipson, and true fact about me, I don't currently own a car. I live in Portland, Oregon, and I get around just fine with public transportation, walking, and so on. I've had cars at plenty of other times in my life, and I like driving, but I choose not to have a car for the time being. and one of the biggest consequences is that I end up walking a lot. And I love walking. It's such a healthy thing to do. It's awesome. And that is all for today. I wish you a fabulous week ahead. Cheers.