E42: Okay, but what happens when a bird gets sick?

Scott Taylor: Being sick sucks. It just does. Whether it's a cold or flu, COVID, food poisoning, or something worse. When your body is on the defense, you always feel lousy. And sometimes our immune defenses fail us. If you haven't noticed, I'm currently in the final stages of a lovely cold. The first time I got COVID, I was pretty lucky. I'd already been vaccinated, so my body was prepared to fight off the virus. My adaptive immune system was ready. Even still, I did not feel good at all. Sore throat, stuffed up nose, headaches. I temporarily lost my sense of smell, which was a crazy experience. I was tired. I didn't feel like doing much of anything, and I spent 10 days isolated from my partner. But I survived, unlike many people who got COVID before the vaccine was available, before any of us had any adaptive immunity to this novel virus.

Scott Taylor: Adaptive immunity is an amazing thing, and we're not the only creatures that have it. Birds have an adaptive immune system too. Remember how we can vaccinate condors against bird flu?

Scott Taylor: Which brings us to the topic of today's episode. Okay, but what happens when a bird gets sick? To explore this topic, we'll talk with Dr. Andrea Townsend, an associate professor of biology at Hamilton College.

Scott Taylor: As a primer before we get into it, birds and mammals both rely on the same basic two-part immune system, innate defenses that respond immediately and adaptive defenses that learn and remember specific pathogens. But the details diverge in some interesting ways. Take B cells, a type of white blood cell, the cells that manufacture antibodies. We grow ours in bone marrow. Birds grow theirs in an organ we don't have at all, a small pouch near the back end of the gut called the bursa of Fabricius, which fittingly sounds like a pretty [bleep] Roman gladiator. Our first responders to an infection are called neutrophils, white blood cells that swallow invaders whole. Birds send heterophils instead. Same job, different mechanism. The antibody doing most of the heavy lifting in our blood is immunoglobulin G, while birds run on immunoglobulin Y, an older take on roughly the same idea. And birds don't have lymph nodes at all. We have hundreds of them, little filtration stations where immune cells meet the enemy and coordinate a response. Birds scatter that tissue in loose patches throughout the gut, spleen, and other organs instead.

Scott Taylor: And remember how hot birds can be? In episode 33, we learned birds are little furnaces with body temperatures often 40 to 42 Celsius, or 104 to 108 Fahrenheit. It turns out an extra warm body may act as a built-in fever that discourages many pathogens before an active immune response even kicks in. The two lineages, mammals and birds, have been evolving these systems independently for roughly 300 million years since their last common ancestor. So while the overall strategy looks familiar, the components underneath are often quite different. Now, on with the episode. Stay tuned.

Scott Taylor: Welcome back to the podcast, everyone. I'm really excited to have Andrea with us today to talk all about what happens when birds get sick. So thanks for joining us, Andrea.

Andrea Townsend: Thanks for having me Scott.

Scott Taylor: Of course. I thought we could start off with a little bit of your origin story pertains to birds and sickness. So you're known around your campus as the Crow Lady, apparently, because they follow you around. How did you start studying crows?

Andrea Townsend: So I became very interested in the phenomenon of cooperative breeding. So I know you guys have talked about that on the pod before. So it's when you have basically a family with a bunch of babysitters. So the adult kids stay home and help their parents raise their younger brothers and sisters. And I started seeing this phenomenon. It's actually a really rare phenomenon in birds, something like, depending on how you define it, like 3% of bird species are cooperative. And most of them are in the tropics. But I wanted to study them on the Cornell University campus, because that's where I was. And there was only one choice, which was the American Crow. That's the only cooperative breeder in New York State. And it just so happened that there was already a marked population, a long-term study population of American Crows there. And it was established by Kevin McGowan and Anne Clark. And they kindly allowed me to join their research group. And so I got to be part of this long-term study of the American Crow. I just can't go back to other birds because they're just so interesting. So they're not just kids staying home with their parents, although there's obviously some of that. So they can stay home for many years, like seven years. Some of them will stay home and help their parents. And then some of them will go away and try to set up their own territory. And then they'll come back and they'll have an injury or a droopy wing or a cut. And their parents will just let them come back. So it's like watching birds try to become independent, fail, and then come back home.

Scott Taylor: Yeah. Just like people.

Andrea Townsend: Yeah, just like people. And then sometimes there's uncles and then there's sometimes there's just random birds that are not, you know, that just join a family group. But then not only that, but then they're very variable in how they get along. Like some family groups are really nice to each other and they're peaceful and they're playful. And then some family groups are just really dysfunctional. They're just... constantly fighting and there's just a lot of angst in the groups so that got me really interested too so it's just like a soap opera and then when we talk about their mating system they also have a very bizarre mating system so all these things like it's a constant discovery when you're watching these families.

Scott Taylor: Yeah, for sure. So then how did that like interest in, I mean, crows are fascinating. We get a lot of questions about how can I become friends with a crow? Can you please talk more about crows and all of these things? So people love crows. I think that's a broad feeling and their social behavior is amazing. But then how did that turn into studying crow diseases specifically? Like what was that flip for you?

Andrea Townsend: So I started studying them in 2005. And that was right after there was an outbreak in Ithaca of West Nile virus. So it's an emerging infectious disease. We brought it over, we think, from the Middle East in 1997 to New York City. And then it's moved across North America since then. Yeah. And it has outbreak years and then it disappears for a little while, but stays at really low levels. So it's basically it's become endemic, we call it. So something that's constantly around at low levels, but then has outbreaks periodically. Their first outbreak of West Nile virus in 2003, 2004. And more than half of the birds died. So of the marked birds Yeah.

Scott Taylor: Wow. And West Nile is a vector disease, right? So it's vectored by mosquitoes.

Andrea Townsend: And certain bird species are highly susceptible to West Nile virus. So if an infected mosquito bites them and they become infected, then all of them die. So crows, well, at least as far as we know, all of them die. The initial studies, all of them were dying. They might have developed some resistance over time. That's an ongoing area of research. So crows are highly susceptible, all the corvids, so that's the jays, ravens, also a lot of raptors are highly susceptible, so hawks, eagles, owls, highly susceptible to West Nile. Epidemic had just occurred. So it was coming into this really sort of tragic, devastating time where half of the birds in the population, more than half, had disappeared. And everything was just in shambles. So normally they're in these very stable, long-term social groups. And now everything had gotten disrupted. Because one kind of sad thing about West Nile is that it doesn't... Most diseases, most endemic diseases, and this is true in people, it's true in birds, they mostly affect the young because youngsters, young humans, young birds don't have an adaptive immune response yet. They haven't been exposed to stuff and then they can mount a response to it later. So just like baby humans get sick all the time, baby birds tend to be the ones that are getting sick. Have high mortality from disease. And by the time they get past that first year, they've got a much stronger immune response. You don't see the same diseases in an old crow. Anyway, West Nile virus comes in. It's a brand new pathogen. And there's no resistance in the population. It's kind of like COVID in humans, where we are adults are susceptible to it because it's not something we had been exposed to when young. West Nile virus is the same way. There was no resistance in the population. The old birds were just as likely. The old birds that should have had a long, you know, life full of potential, they were dying at equal rates to the young birds. So, yeah, that's something that you see with emerging infectious diseases. Often you'll see... higher mortality than you'd expect in older age classes.

Scott Taylor: Yeah, we see that in bird flu as well, that it's taking out kind of just everyone. There is some immunity evolving, but it is killing kind of indiscriminately compared to an endemic virus or disease that would take out the young first. Yeah, and in crows, you know, you just talked about the complexity of their social behavior and all of this. And so if you're losing adults, that's gotta be particularly bad for like the stability of the whole population, really.

Andrea Townsend: Yeah, the stability of the family group and the stability of the population, perhaps, but definitely the family group. So, you know, you're losing the mom, you're losing the dad, you're losing a helpful brother and sister, you're changing everything. And life is hard for a young bird. So I'd say the vast majority of them die that first year, whether it's from predators or disease. But then once you get to be like one, you should have a nice long life. You know, crows can live 20 years. I think the oldest known crow is 19 years. I just asked Kevin McGowan that.

Scott Taylor: Oh, nice. That's the oldest known wild crow. Wow. So...

Andrea Townsend: Yes. Oh, in captivity, I think the oldest known crow was like 60.

Scott Taylor: That's amazing.

Andrea Townsend: So I came into this long-term population, birds were dying. My initial plan was to look at the genetic mating system of American Crows. So like most birds... socially monogamous, but I thought maybe something interesting is going on. Maybe they're cheating on each other. How did that affect cooperation within a group if they're cheating? And so that was my initial plan, but then they're all dying of West Nile. So my... ideas and my research shifted to, okay, how does disease affect mating strategies? And my thought was that they would do something smart. Like maybe they went in times of disease, maybe they would choose like even better mates. Maybe they would choose these high condition mates, or maybe they would cheat a lot and hope that some of their kids were surviving because they just happened to get some resistance gene. So that was what I had predicted. But what it turned out was very shocking, which was that crows tend to inbreed a lot. Yeah.

Scott Taylor: Hmm. Okay. Interesting. Cause like they have pretty large populations and you might expect, like, I would probably have made the same predictions as you that they would outbreed, to diversify the population. How close to like brother, sister pairs and that sort of thing.

Andrea Townsend: Oh, yeah. So a lot of uncle-niece social pairings. So those are the social mom and dad. But then there's also, so you have these adult sons within family groups. There were extra pair matings between moms and their adult sons. Yeah. So we call that incest, first order pairings, you know, and you might be kind of like having a disgust response. And that is this totally evolutionarily adaptive and appropriate because and it's one of the few rules that most animals obey. Like we avoid inbreeding and there's really good reasons for that. And especially when it comes to disease. Because when you mate with, there's lots of good reasons, like you could express deleterious alleles, but I won't talk about that one. But another good reason to avoid inbreeding when there's lots of disease around is by, if you mate with someone who's unrelated to you, your babies are going to be more genetically diverse, and therefore they're going to recognize more pathogens, But if you mate with kin, your babies are going to be less genetically diverse. They won't recognize as many pathogens. So this was the opposite of what I expected to find, which is really high levels of mother-son. There's a lot of uncle-niece and some mother-son. And this has been true in now, I've studied three populations, and it's happening in all three of them.

Scott Taylor: Really? So it's not just like an Ithaca specific thing.

Andrea Townsend: Not just an Ithaca thing, no. Yeah.

Scott Taylor: Interesting. So crows are just kind of prone to inbreeding regardless of population size?

Andrea Townsend: No matter what we look at we find accumulating costs of inbreeding so they tend to be in poor condition they don't live as long and they tend to die with signs of disease. And it's not just West Nile. One of the most common things we see is avian pox, which is basically like smallpox in humans. It's the bird version of it. So it's not transmissible to humans, thank God, because it's really gross. Have you guys talked about avian pox before?

Scott Taylor: We have not talked about avian pox.

Andrea Townsend: Okay. It's really sad. They get these lesions that can be on their face. It can make them blind. If they get them around their beaks, they can't swallow anymore. So it's deadly sort of by a physical process. And sometimes they can recover. Then you'll see it on their feet. Sometimes they can recover. If it's just on their feet, they can recover sometimes from that. But if it gets on their face, usually they don't. At least if you're a crow.

Scott Taylor: And the inbred crows, have you seen that they're more susceptible to pox as well then? Just like across the board, yeah.

Andrea Townsend: Oh, yeah. Yeah so sometimes when you know that a brood was produced mother-son it's just a matter of time you just start watching that brood and then you'll start seeing the pox lesions you know even in the nest yeah so yeah.

Scott Taylor: Even while they're still in the nest? Oh, wow. So there's like really immediate costs. Yeah. Wow.

Andrea Townsend: My lab is mainly studying or focused on Campylobacter right now. And so Campylobacter is a disease. It's a pathogen. It's a bacterial pathogen. It has a fecal-oral transmission route, like if you are following the Cyclospora. It's nothing like Cyclospora because Cyclospora is a protist, and Campylobacter is a bacteria. But it shares the...

Scott Taylor: But they both come from poop that gets into a mouth. That's the route.

Andrea Townsend: Yeah, exactly. They've got a poop-to-mouth transmission route. And birds are considered a reservoir for it, so it's really common in birds. And it's thought to be commensal in chickens, so it causes no harm, but it causes a lot of harm in crows. So we found it's not like immediately lethal, and that's why I study it. So they're in poor condition. They're anorexic, so they've got very little interest in eating at all. Yeah, and they don't live as long. So over a 12-month period, they've got a lower survival probability.

Scott Taylor: And Campylobacter then is it native? Like, is it a native parasite or disease to North America or did it come from chickens?

Andrea Townsend: That is such a good question. Yeah so there we looked at the genomics of Campylobacter and crows carry two different strains one is crow only their very own strain of Campylobacter and that okay so first of all I should say about 60% of crows are carrying this in the populations.

Scott Taylor: Oh, wow. So it's like hugely, yeah. Well, yeah. Gives you lots of individuals you can study. So great choice from a research perspective.

Andrea Townsend: So many of them are carrying this Yeah, there was a reason we picked it. So most of the, well, I'd say maybe 70% of them are carrying this crow only strain, but about 30% of the ones that are infected are carrying the human strain. So ones that are carried by humans, goats, livestock, chickens, I guess that's not human, but we're all sharing a strain and crows are getting that. So that's probably new to crows that might be like spillover from us to crows. And one thing that'd be really cool to know is, okay, maybe they're adapted to their own crow specific one, but maybe it's this new one that's making them sick.

Scott Taylor: So you're saying with Campylobacter, they have little interest in eating. They might have higher mortality on the longer term. But what are some of the other signs that a crow is trying to fight off a Campylobacter infection?

Andrea Townsend: One thing we've been studying is cognitive effects. So crows are smart. So that led to a study of variation among individuals. So why are some crows performing well on tasks and some performing less well? And it turns out that diseases seem to have a really strong effect on how they do on these cognitive tasks. Yeah and there's actually not much information from wild animals about how disease affects their cognitive abilities so this has been really fun so what we do is we bring crows into the aviary wild crows and we have them for about three weeks and we analyze them so about half of them are carrying Campylobacter just naturally.

Scott Taylor: And you just figure that out from like a fecal test or cause that, yeah.

Andrea Townsend: Yeah, it's really easy. It's like a COVID cassette test, except you just put some poop in there.

Scott Taylor: Oh, nice. So it's super fast. Yeah.

Andrea Townsend: And so then we give them a battery of tests. So we give them problem-solving tests. Where they have to pull up a string with their beak and step on it and pull a few times until they get the food. There's other ones where they have to pull a couple of levers to get food. There's memory tests, so associative learning. Can they memorize a color with a food? And then there's spatial memory. So if you hide stuff, can they remember where it's been hidden? What we found is that sick crows infected with Campylobacter, don't do well on these tests. They're less likely to try, and.

Scott Taylor: Oh, so they just have lower motivation? I mean, I hear that. Like, how do you... When I have a cold or flu, I'm not super motivated to do anything at all. So that's interesting.

Andrea Townsend: Totally, yeah. So they're like, ugh, I don't want to. And then, of course, they're not food motivated as much. And we know that because we give them endless food. We measured how much they ate. And the sick ones, first of all, weren't. When they were just given a big bowl of food, they ate less. And then, of course, they're not going to try as hard on these cognitive tests with a food reward. So some of them don't even try. And when they try, they might try a few times. They're like, ugh, you know, and then they'll give up. So that's one issue. But in some cases, that can't explain it. Spatial memory. They're not so good at remembering where food is hidden. And they're trying to find it. They're just going to the wrong bowls. So just not trying doesn't explain it all. They are not performing as well. Yeah. Different pathogens will affect our cognitive abilities in different ways. So there's some, like West Nile virus, that can cause neurological damage. Or COVID in humans causes neurological damage. It causes neuroinflammation. And that's legitimately causing damage to the brain. And that's why some of us experience brain fog. Campylobacter is not like West Nile virus or COVID that causes neuroinflammation. It's a gut pathogen. So how is it affecting the brain? And you guys might have heard of the gut-brain axis. So when your stomach hurts, that communicates to the brain and changes your behavior. So that's the idea. So in this case, it might be triggering changes in motivation or willingness to devote energy towards cognitive tasks, that kind of thing. So different diseases, different pathogens are going to affect your cognitive performance by different mechanisms. But here is one potential example of a foodborne pathogen, a fecal-oral pathogen doing it to a bird.

Scott Taylor: Yeah, no, that's fascinating. On Campylobacter where you've seen the social distancing thing?

Andrea Townsend: Oh social distancing so that was another thing that I expected to happen that crows being so smart would during times of high disease pressure would start social distancing so you know avoiding infected conspecifics or overall become less social and I was listening to your episode with Nichola Hill and she was talking about how she saw some evidence that terns, I think it was. Yeah.

Scott Taylor: Yeah, Common terns would kind of evict a really sick individual that had bird flu. Yeah.

Andrea Townsend: But where I'm going with this is I've seen no evidence for that in crows. They do not seem to avoid sick family members or sick birds in general. And that's interesting. I mean, I don't know if you know about this about crows, but they're also famous because of funerals, this funeral behavior where when a bird dies, they will actually, in some cases, congregate around it, sometimes for days. And that can be really problematic in times of disease stress because sometimes those are, you know, places where you can pick up pathogens one problem with my initial hypothesis with West Nile virus, which was that they should start avoiding each other, is that West Nile virus is transmitted by mosquitoes. And so it's actually worse. So imagine that you're trying to avoid West Nile virus. It's worse for you to go off by yourself, because then all the mosquitoes are going to bite you. What you should do is get in a big crowd and go in the middle. So there's actually evidence for this in birds. If you're in a big roost, you're less likely to be the one to get bit than if you're off by yourself. So that prediction that they should become less social during West Nile virus was actually flawed to begin with.

Scott Taylor: Right, because then you're the one target.

Scott Taylor: Thinking just back to like, okay, so you have these sick crows. They're not that motivated to do your memory tasks or your problem solving tasks. What other, like when a crow is sick, what does it, are there behaviors that it undertakes to try to cope with the disease it's experiencing? Like what other coping strategies do wild birds have when they're experiencing infection? If that infection doesn't just kill them right away.

Andrea Townsend: Well, there's a classic suite of behaviors we call sickness behaviors, and it's really conserved across the animal kingdom. So humans do it, dogs do it, bees do it, birds do it. So at least for certain pathogens, when they get infected, they will exhibit all the things that you might do when you're sick. They're less active. They tend to curl up in a ball. With a bird, they might fluff up their feathers. They're unmotivated to eat and drink and have sex and be social. And what else might they be? Solve problems, apparently. Yeah.

Scott Taylor: Yeah, do your annoying tests. I can't imagine if someone plucked me out of my house when I was like in the middle of a flu and just was like, solve this, read this. I'd be like, leave me the [bleep] alone.

Andrea Townsend: When you have like an awful stomach ache and diarrhea, you know, come on, solve my problem.

Scott Taylor: Do you see evidence of a man cold? Like are the male crows bigger wimps when they're infected? I would love if that was like an evolutionarily conserved trait or not just in people.

Andrea Townsend: That is awesome. You know, and I'm totally seeing a paper. No, I have not. You know, and we totally could because we've never separated. You would think this would be an obvious thing to do. We've never separated out by sex if they're willing to participate, for example, or in these tests when they're sick and not sick. So such an obvious next step. The data are there. Put in sex in that analysis. So yeah, I'll let you know the next time I see Scott.

Scott Taylor: You have the data. Yeah.

Scott Taylor: I would love to know. I mean, there probably isn't because, yeah, whatever. It feels made up in humans anyways, but something funny to check out.

Andrea Townsend: Yeah. But if there is a man cold in crows, that would be interesting. There's some evidence that testosterone can suppress an immune response. And so whether that leads to birds just not exhibiting the same sickness behaviors or being more likely to depending on the time of year, that would be an interesting question.

Scott Taylor: Oh yeah. That would be super cool. Since those circulating hormones are really, like they really ramp up before the breeding season. Yeah. Yeah. I was going to make.

Andrea Townsend: There's some evidence that in the breeding season, some birds will hide if they're sick. They will not exhibit sickness behaviors. The idea being that too much is at stake.

Scott Taylor: Is there an equivalent of like, typically flus and colds are more common in the fall and winter in humans. Is there similar evidence of that seasonal variation in birds? I guess with West Nile, you have to have the vector in order to have the disease, so there must be more infections in the summer. But what about like Campylobacter or.

Andrea Townsend: Yeah, well, those are interesting questions, and it will vary with the pathogen. So things like H5N1, it's starting to ramp up. So avian influenza is, I've seen it starting in August, and then it... increases through the winter months so through February or now maybe through January I've seen it so basically increasing through January and I haven't seen it there wasn't H5N1 in my population at least last year but it has been here in the previous two years.

Scott Taylor: Oh, interesting. So it was there for a couple of years in your crows and then gone for a year.

Andrea Townsend: Last year, no cases. So fingers crossed. For West Nile virus, it will track mosquito numbers. So those tend to start in, you start seeing it in birds in July and peak in August and then, you know, drop off. Things like Campylobacter, so interesting. So it seems to be always around, like whenever I test them, maybe lower in the summer, more in the winter. But I think that's largely social behavior. So I don't know if y'all have seen the roosts, but they're amazing. But there's a lot of poop happening at those roosts. And they're not just pooping on the ground. They're also pooping on each other. And then they do this adorable thing where they preen each other. It's called allopreening. And they're preening themselves. So you can imagine that this is a great time to be picking up fecal-oral pathogens. And so we tend to see higher prevalence of Campylobacter, foodborne pathogens, midwinter when there's a lot of birds around.

Scott Taylor: So you've described a snowball effect where stressed environments make animals sick and then sickness impairs the ability the animals have to deal with the stress that we're causing, whether that's, you know, urbanization, forest clearing or whatever. So with things like avian flu and other diseases reshaping ecosystems, you know, we try to point out that there is hope as regularly as we can, although there are a lot of challenges facing birds. So any hope would be great to hear too.

Andrea Townsend: Yeah, this is a tough one. Well, West Nile virus has been around for a while and it's here to stay. So it's endemic now, just like COVID is here to stay. It's endemic. But just like COVID, West Nile virus had an outbreak that was pretty devastating, killed a lot of birds. But then what tends to happen, at least with like COVID and West Nile virus, is it goes away or it goes to really low levels for a while. And so at least in crows, and this is true for all birds that are affected by, say, West Nile virus, their populations recover to some extent. And so there's time for the populations to recover. We have, there's still a lot of crows out there. So these things aren't constant pressures. And so it's pretty rare when pathogens themselves drive a species to extinction. It's happened, especially like in islands. But yeah, like, yeah.

Scott Taylor: Yeah. Islands and right now with H5N1 and seabirds, although there will probably still be a recovery there, but it's hard to know. And you know, with H5N1, just making it like when we released the episode, it wasn't in Australia or New Zealand yet. And now it is. And so it'll be interesting to see, especially like if bird populations are already small, because we've driven them to small sizes for all the other reasons that you know, introduced predators, loss of habitat, then we need to be concerned. But yeah, with some of our more widespread species, there is time evolution happens and diseases evolve on both sides, right? Like the birds can evolve resistance and the diseases typically will evolve towards being less virulent or less deadly. But yeah, so there is some hope. Yeah, it varies. Yeah.

Andrea Townsend: It varies, but yes, there's the idea that they don't want to kill all their hosts, because then they'll drive themselves extinct.

Scott Taylor: Yeah, otherwise you can't transmit super well. Yeah.

Scott Taylor: We've reached the part of the show we call That's B.S. Or That's Bird Stuff, where we give our guests an opportunity to debunk a myth that ruffles their feathers. So, Andrea, what do you want to call B.S. On?

Andrea Townsend: Okay, so this might be more sour grapes than a myth, but I'm frequently asked if crows bring me gifts. And this is a very irritating question to me.

Scott Taylor: Because the answer is no.

Andrea Townsend: The answer is no. Now, and I have a lot of crow friends. Like, yeah, everywhere I go, I have crows because I'm throwing them peanuts. Okay, let's be honest. Let's be, let's call a spade. But yeah, so they're just wherever I go. So down the street, on campus, in my car, on my bike, it doesn't matter. There's just crows following me, which is, you know, it's so fulfilling. And I also have crows in an aviary who I consider friends.

Scott Taylor: Right, okay. So you... Yeah.

Andrea Townsend: And I have yet to receive a gift. And yeah, I know. So I'm jealous, but I also have, I'm skeptical that this occurs. So in the, and it's probably because I'm jealous, but in the aviary, sometimes crows will be carrying around, they carry around toys sometimes, like a piece of bark mulch. And when I come in, they might like put it down because they want to hang out with me. Is that a gift?

Scott Taylor: If you want it to be, maybe if you need it to be, it could be again.

Andrea Townsend: I mean, if I, I'm like, is this bark mulch for me?

Scott Taylor: There's still hope. You know, someday. Yeah, we can have you back on. Once you receive your gift, we can do a whole episode about how you felt.

Andrea Townsend: Yeah. I still have time. And I'll apologize. Yeah. Thanks, Scott.

Scott Taylor: Awesome. Well, thanks so much for joining us on the podcast today. It's been really fun to chat all about what happens when birds get sick. So appreciate you taking the time.

Scott Taylor: Birds are dinosaurs, and around here we like our snacks, so we end each episode with a dinosaur nugget. Today's nugget is, brain fog isn't just a human thing. About 60% of Andrea's crows are carrying a gut bacteria called Campylobacter, and it doesn't kill them outright. It just makes them worse at being crows. Infected birds quit on puzzles they should be able to solve, and they forget where they stashed their food, going back to the wrong bowls again and again. The infection never touches the brain. It sits in the gut and talks to the brain through the gut-brain axis. The same wiring that makes you want to lie down when your stomach hurts. So a bird whose whole survival strategy is being clever picks up a stomach bug and the first thing it loses is its cleverness.

Scott Taylor: That's a wrap on this week's episode. Okay, but what happens when a bird gets sick? If you're thankful I powered through a cold to bring you this episode, you can pay me back by leaving a rating or a review and following the show wherever you're listening. Think of it as chicken soup, but for a podcast. Now, if you'll excuse me, I'm going to go exhibit some sickness behaviors and lay down. We'll catch you next time. Byeee.

This transcript was generated using AI-assisted transcription and may contain errors or omissions. Please refer to the audio or video episode for the most accurate representation.