Speaker 1: Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Speaker 2: Hey, welcome to Stuff to Blow Your Mind. Robert Lamb.
Speaker 2: Here in today's episode, I'm going to be chatting with
Speaker 2: Rosalind Dakin, Associate professor at Carlton University in Ottawa and
Speaker 2: principal investigator at the Dynamic Behavior Lab. We're going to
Speaker 2: be chatting about hummingbirds, as she and her co authors
Speaker 2: just had a new paper published in the Journal of
Speaker 2: Zoology Turning trade offs. Hummingbird power reserves are used to
Speaker 2: decrease turning radius or increase turning velocity. So, without further ado,
Speaker 2: let's jump right into the interview. Hi, Rosalind, Welcome to
Speaker 2: the show.
Speaker 3: Hi, thanks for having me.
Speaker 2: So we're going to be talking about hummingbirds today. We're
Speaker 2: already really enjoying the company of hummingbirds down here in Atlanta.
Speaker 2: Have they arrived up there where you are? Yeah, you're
Speaker 2: in Ontario?
Speaker 3: Correct, Yes, exactly, I'm in Ottawa, Ontario. And they arrive
Speaker 3: the first week of May the ruby started. Hummingbirds show
Speaker 3: up almost like clockwork every year.
Speaker 2: It's always a joyous occasion here at my house when
Speaker 2: we finally see the first humming birds of the season
Speaker 2: appear at our feeders and flowers, and I think, you know,
Speaker 2: at first it's the magic of them being here, the
Speaker 2: way they move and all, But as you begin to
Speaker 2: observe them, you really begin to notice how intensely territorial
Speaker 2: they are about their flowers or about the cute little
Speaker 2: feeder we've put out for them. Can you tell us, like,
Speaker 2: why are they so territorial about this? Sometimes as humans
Speaker 2: putting out feeders, we want to tell them like, no, no,
Speaker 2: there's plenty you can share, and they're generally not having
Speaker 2: any of that.
Speaker 3: Yeah, that's right. They have super competitive behaviors, and that's
Speaker 3: something that we've been studying in my lab. Why they're
Speaker 3: like that, I think it all comes down to their
Speaker 3: super high metabolic rates. Their lifestyle relies on having a
Speaker 3: steady stream of calories throughout the day, and if they
Speaker 3: go even an hour without feeding, depending on how much
Speaker 3: energy fat store they have in their body, that can
Speaker 3: be death an hour without a meal. So those food
Speaker 3: sources are really really valuable to them, and their metabolic
Speaker 3: rates are so high. If you could scale a hummingbird's
Speaker 3: body up to the size of the average adult human,
Speaker 3: it would be like if you or I had to
Speaker 3: eat one hundred and fifty large pizzas in a day.
Speaker 2: Wow, Now how can their wings that move so fast
Speaker 2: to repel thems of the air.
Speaker 3: Yeah, so in order to be able to hover, hummingbirds
Speaker 3: have to beat their wings, depending on the species, between
Speaker 3: thirty to eighty times per second. So if you think
Speaker 3: about a full wing stroke, that's your arm being fully
Speaker 3: extended back, coming forward, and then back again and repeating
Speaker 3: that cycle. For species like ruby throated hummingbirds, fifty times
Speaker 3: every second. It's incredibly fast. So they have so that's
Speaker 3: why they have such high metabolic rates, the highest of
Speaker 3: any vertebrate animal per unit body mass. But they have
Speaker 3: a lot of anatomical adaptations that are required to be
Speaker 3: able to do that. So for example, they're pectoral muscles
Speaker 3: that draw the wings down that activate the downstroke are
Speaker 3: hypercha feed. They're really really large. But similarly, they have
Speaker 3: another muscle, the super corecoidous muscle that draws the wing
Speaker 3: back up, and it's also hypercha feed. It's also extra large.
Speaker 3: In hummingbirds, they have skeletal adaptations as well, so the
Speaker 3: muscle that the bones that those muscles attached to have
Speaker 3: to be larger and more robust than they are in
Speaker 3: other birds that have more typical wing beat frequencies, and
Speaker 3: they also have dramatically modified and that so the bones
Speaker 3: of their wing, these are the bones that we can't see.
Speaker 3: We just see the feathered part of the wing, but
Speaker 3: inside the hummingbird's wing they're humorous is really really short.
Speaker 3: It's so short, it's almost like a little dot, you know,
Speaker 3: It's just a couple of millimeters in length. And their
Speaker 3: their wing is mostly hand And what that does is
Speaker 3: it means that the heavy parts of their arm bones
Speaker 3: are drawn in close to the body to make it
Speaker 3: easier to beat those wings so fast. But it also
Speaker 3: means that those muscles that are activating those wingstrokes are
Speaker 3: working over a shorter distance, and so that makes it
Speaker 3: physically possible for them to beat their ways at this
Speaker 3: incredibly high frequency.
Speaker 2: So what evolutionarily has driven this development this arm's race
Speaker 2: of hummingbirds. Is it just their diet and how they
Speaker 2: need to feed it, is it predators, is it other hummingbirds? Like,
Speaker 2: how does it all come together?
Speaker 3: Yeah, that's a super interesting question and one that we
Speaker 3: have hypotheses, but it's still an active area of research.
Speaker 3: If we go back, well, let's start with looking at
Speaker 3: what we have today. The hummingbird family is extraordinarily diverse.
Speaker 3: There's three hundred and sixty six different species and they
Speaker 3: live in the Americas, so South America, Central America, the Caribbean,
Speaker 3: and subspecies here in North America. That's incredibly diverse, and
Speaker 3: they've radiated, they've diversified into all of these species over
Speaker 3: the past twenty five million years. And if we look
Speaker 3: at their closest relatives in the evolutionary tree, the family
Speaker 3: tree of all birds, those are swifts, which are also
Speaker 3: super agile birds. They're distributed across the globe. We have
Speaker 3: swifts in North America. We also have swifts in Europe
Speaker 3: and Asia that are aerial insectivores. So swifts spend almost
Speaker 3: all of their time in the air catching flying insects,
Speaker 3: so they have to be like little fighter pilots to
Speaker 3: be able to chase down their prey. So the first
Speaker 3: hummingbirds evolved around thirty million years ago from an ancestor
Speaker 3: that was a really really acrobatic predator in the air,
Speaker 3: and swifts have some of the same skeletal adaptations that
Speaker 3: we see in hummingbirds. They have an enlarged keel. That's
Speaker 3: the part of the bone on the breastbone where those
Speaker 3: pectoral muscles attach, and swifts also have changes in their
Speaker 3: wingbones that we see in hummingbirds as well, So that's
Speaker 3: part of how we know where the hummingbirds fit in anatomically,
Speaker 3: but also genetic studies have established what those relationships are.
Speaker 3: So yeah, the first hummingbird was something something like an
Speaker 3: insective war chasing down insects, and somehow, you know, maybe
Speaker 3: they started to prefer insects that were associated with flowers,
Speaker 3: and maybe that led to them consuming some nectar. We
Speaker 3: don't know exactly what happened to produce this fift towards
Speaker 3: being so specialized on flower nectar. But the other mysterious
Speaker 3: part is that the earliest ancestor, the earliest fossil ancestor
Speaker 3: we have of hummingbirds is not at all in the
Speaker 3: same part of the world where we have all of
Speaker 3: the species that we can observe today. The closest fossil
Speaker 3: ancestor of hummingbirds they come from Europe, so fossils with
Speaker 3: a lot of those hummingbird typical features, a long bill,
Speaker 3: an exaggerated keel, and different wing proportions. Those have been
Speaker 3: found in Poland and in France and multiple places, so
Speaker 3: they arose in Europe we think, and at some point
Speaker 3: made their way over to the Americas thirty twenty five
Speaker 3: million years ago and from there diversified into very many
Speaker 3: species day and a lot of that is the diversification
Speaker 3: is probably due to specializing into different areas in the
Speaker 3: Americas and in the Caribbean.
Speaker 2: So they're enhanced maneuver built in their power reserves, which
Speaker 2: we're going to get into when we start talking about
Speaker 2: your study here. This is largely for inter hummingbird competition
Speaker 2: or do they have aerial predators they need to worry
Speaker 2: about as well?
Speaker 3: They may have some effective predators. That's not something that
Speaker 3: we observe very often, but we see a lot of
Speaker 3: competition both between species and also within species, so especially
Speaker 3: among males within a species, competing for a territory, competing
Speaker 3: for a food resource. The other area where we see
Speaker 3: them using their acrobatic skills is when they're courting mates.
Speaker 3: So in very many species, the males will try to
Speaker 3: impress females by doing an elaborate display in the air,
Speaker 3: and the way that display goes will differ in different species,
Speaker 3: but often they're zooming back and forth, reaching really high
Speaker 3: speeds and turning quickly as part of that display, all
Speaker 3: at the same time as they show the female their
Speaker 3: colorful plumage and sometimes like make certain sounds while they're
Speaker 3: doing those as place as well.
Speaker 2: So getting into your research a bit more here, tell
Speaker 2: us a little bit about the Dynamic by Behavior lab
Speaker 2: and how hummingbirds factor into your work there.
Speaker 3: Yeah, so we are interested in differences between individuals and
Speaker 3: differences between species and when performance is such an important
Speaker 3: part of how they survive, how is it that, like
Speaker 3: what determines which individuals are dominant over which others, who's
Speaker 3: winning those competitions, what traits determine who wins, But also
Speaker 3: for individuals that are subordinate, what options do they have?
Speaker 3: How do the subdominant individuals make a living? Those are
Speaker 3: some of the questions we're studying in my lab. So
Speaker 3: we measure things like they're an individual bird's ability to
Speaker 3: generate power in flight, and we also measure their behavior
Speaker 3: in big arenas where we can pit multiple birds against
Speaker 3: each other competing over a food resource and seeing both
Speaker 3: who's dominant, but also how are they using flight maneuvers
Speaker 3: to outdo each other.
Speaker 2: Now, how do you go about studying something like this,
Speaker 2: because hummingbirds, i imagine, are not easy creatures to study anyway,
Speaker 2: and then you're dealing with some difficult to measure properties here.
Speaker 3: Right, Yeah, it takes a lot of patience. And one
Speaker 3: of the nicest assays that's possible to do with hummingbirds
Speaker 3: is a load lifting assay where we can measure the
Speaker 3: maximum power they're able to generate with their flight apparatus,
Speaker 3: with those muscles that are activating the wings. And we
Speaker 3: do that assay in a chamber that's think of like
Speaker 3: a vertical cylinder with kind of an open bright light
Speaker 3: at the top, and a humming bird at the bottom
Speaker 3: of that chamber is going to be highly motivated to
Speaker 3: upwards try to escape, and we use an assay that
Speaker 3: was developed decades ago by other scientists where we put
Speaker 3: a little ring around the bird's neck that's attached to
Speaker 3: a string of beads, and when we know the weight
Speaker 3: of the beads along that chain, we can record what's
Speaker 3: happening when the hummingbird gets released from the bottom of
Speaker 3: the chamber. And if everything is set up suitably for
Speaker 3: the bird as they try to escape upward with everything
Speaker 3: they've got, we're able to measure exactly how many weights
Speaker 3: or how many exact weight of the beads on that
Speaker 3: chain that they're able to lift. The higher they go,
Speaker 3: they're lifting more and more weight until they hit a
Speaker 3: maximum and return back to the bottom of the chamber.
Speaker 3: So we're able to develop an assay that just fits
Speaker 3: with their capabilities their motivations to measure their maximum weightlifting ability.
Speaker 2: So essentially the tiny necklaces on hummingbirds is a part
Speaker 2: of the study exactly.
Speaker 1: Yeah.
Speaker 3: Yeah, so we have to make those necklaces. Yeah.
Speaker 2: Wow. So this this latest study published in the Journal
Speaker 2: of Zoology, really gets into their their maneuverability and their
Speaker 2: power reserves. Can you lay out how these these two
Speaker 2: aspects are linked. As I was reading the paper, I can't.
Speaker 2: I really kept thinking of hummingbirds in like video game
Speaker 2: terms and imagining like little meters at the top of
Speaker 2: the screen.
Speaker 3: Yeah. So a couple of questions motivated this study, and
Speaker 3: it was led by my colleague Paulo Segre and my
Speaker 3: co author Doug Altuler. So one of the questions was,
Speaker 3: when we're measuring their maneuvering performance, which includes lots of
Speaker 3: complex behaviors that have a lot of degrees of freedom.
Speaker 3: How tightly can they turn, how fast can they move
Speaker 3: when they're turning, How fast can they accelerate decelerate? When
Speaker 3: we're measuring those maneuvers, it's really hard to capture what
Speaker 3: is a bird's maximum ability? The more freedom you give
Speaker 3: them in a space where you're capturing what they do,
Speaker 3: the less well defined maximum is because there's so many
Speaker 3: different ways to move in a completely open environment. So
Speaker 3: we've been studying maneuvering ability in across the different hummingbird
Speaker 3: species for some years, but we wanted to know is
Speaker 3: the power they're able to generate in a more constrained
Speaker 3: assay like our low lifting assay, is it predictive of
Speaker 3: some maximum that we're able to capture in this free
Speaker 3: flight assay. That was the motivation for that study, so
Speaker 3: led by Pollow. What Pollo did was he reasoned using
Speaker 3: fundamental physics that one of the basic maneuvers that they
Speaker 3: use very frequently to turn, which we're calling an arcing urn,
Speaker 3: which is basically just a level turn that if you
Speaker 3: look at it from above, you follows a smooth arc.
Speaker 3: He reasoned that those arcing terns that we can build
Speaker 3: a physical model of the forces that they need to
Speaker 3: to produce those arcing turns, and we can test whether
Speaker 3: the maximum load that a bird is able to lift
Speaker 3: in our low lifting assay does that correspond with the
Speaker 3: maximum that they're hitting up against as they redirect forces
Speaker 3: during those arcing turns.
Speaker 2: So one of these arcing terns you're describing here, would
Speaker 2: this perhaps be one of these maneuvers we see when
Speaker 2: one hummingbird chases another hummingbird away from a feed or
Speaker 2: flowers in our yard.
Speaker 3: Yes, absolutely, yeah, and yeah, definitely they'll use arcing urns
Speaker 3: during chases. They'll also use arcing turns during obstacle avoidance,
Speaker 3: which is really important to a fast moving animal. Those
Speaker 3: collisions could be deadly.
Speaker 2: Yeah, these the collision avoidance turns. I guess I don't
Speaker 2: notice as much because if they're avoiding collision with my head,
Speaker 2: it's all happening so quickly. But yeah, but sometimes we'll
Speaker 2: be watching them off, and we'll be watching them and
Speaker 2: we'll see one chase the other off, and it sounds
Speaker 2: like that's what you're talking about here.
Speaker 3: Yeah, exactly.
Speaker 2: Yeah, I'm sorry, but I got us off topic here.
Speaker 2: You were describing your analysis of these turns.
Speaker 3: Right, Yeah, So in those free flight essays, we aren't
Speaker 3: telling the birds what to do. They're performing at a
Speaker 3: sort of routine flight level of performance as they're trying
Speaker 3: to avoid the threatening experimenters avoid collisions with the size
Speaker 3: of the flight chamber. But we can capture thousands of
Speaker 3: maneuvers from each individual over a relatively short span of
Speaker 3: time because everything hummingbirds do just happens on much faster
Speaker 3: timescale than other species or than their own lives. So
Speaker 3: if you record a hummingbird for two hours, you might
Speaker 3: capture two thousand arcing turns, for example. And so we
Speaker 3: can computationally pull out the segments of flight that represent
Speaker 3: the arcing turns that we're limited to a level plane,
Speaker 3: and we can apply the physical model that Paolo built
Speaker 3: to say, okay, the redirection of forces as the bird
Speaker 3: is banking its body to execute that turn, what's the
Speaker 3: what's the kind of space of what that looks like
Speaker 3: for the many, many thousands of turns that we captured
Speaker 3: from the different humming birds in our study. We studied
Speaker 3: about twenty individual hummingbirds in that study. And does the
Speaker 3: does the limit of that, but distribution, how does that
Speaker 3: align with our predicted limit from how much weight those
Speaker 3: birds could lift in our highly constrained load lifting assay,
Speaker 3: And what we found was that overall, collectively, the model
Speaker 3: predicts really well the maximum turning performance of the birds
Speaker 3: in that chamber. So the Anna's hummingbirds that we study
Speaker 3: either from the west coast of North America slightly larger
Speaker 3: species than we have here in Ottawa or where you are,
Speaker 3: but they have in our little lifting I say they
Speaker 3: can lift about two and a half times their body
Speaker 3: weight on average, and we can model what that would
Speaker 3: translate to in terms of being able to redirect forces
Speaker 3: to execute that turn. And the birds in our free
Speaker 3: flight experiment, their peak performance matches that peak of what
Speaker 3: we would predict based on their maximum ability. So it's
Speaker 3: really satisfying. It It aligns with our hypothesis that in
Speaker 3: order to be maneuverable, that power has to come from
Speaker 3: their muscle capacity and flight and their kind of excess
Speaker 3: muscle capacity. Their ability to just lift weights vertically is
Speaker 3: going to determine how well they can execute these high
Speaker 3: performance acrobatic maneuvers.
Speaker 2: So as they're flying about during the day, like how
Speaker 2: often are they like at absolutely using up their powers.
Speaker 3: Yeah, that's a really good question that we don't know
Speaker 3: the answer to yet. And how often are they hitting
Speaker 3: their maximum out in nature? Probably not that often compared
Speaker 3: to you know, when you think of like the lifespan
Speaker 3: of a hummingbird and and how much they do during
Speaker 3: it during the day, I would estimate, I would hypothesize
Speaker 3: that it's it's pretty rare that they're executing maneuvers that
Speaker 3: are that are hitting their max. But in our flight chamber,
Speaker 3: you know, it was a pretty small proportion, maybe one
Speaker 3: percent of the turns are kind of hitting that maximum envelope.
Speaker 3: And and maybe it's similar out in the wild. But
Speaker 3: that's something that we'll be able to test in the future,
Speaker 3: for example, by having sensors small enough to put on
Speaker 3: a really small bird. That's kind of the challenge there.
Speaker 3: But a lot at the time of the like you know,
Speaker 3: a lot of their time of the day they spend
Speaker 3: perching and and probably one of the biggest challenges for
Speaker 3: them is maintaining the muscle mass that they would need
Speaker 3: to execute those rare super high performance maneuvers.
Speaker 2: That's absolutely fascinating. Now I have I have another question
Speaker 2: or two about just studying the hummingbird, Like we as
Speaker 2: we observe them, you know, we we obviously pick up
Speaker 2: that they are they're very powerful creatures in their own right,
Speaker 2: but we also get the sense of fragility about them.
Speaker 2: Are they are they fragile to deal with?
Speaker 3: Like?
Speaker 2: What how is it different dealing with hummingbirds versus other
Speaker 2: birds you might be studying in your in your work.
Speaker 3: Yeah, I would say in the lab there their relatives
Speaker 3: are easy to deal with compared to other species. And
Speaker 3: part of that might be they're they're so specialized. If
Speaker 3: you kind of know the conditions they need, they're relatively
Speaker 3: easy to keep healthy. The main point of fragility is
Speaker 3: that's super high metabolic rate. If they run out of food,
Speaker 3: that's catastrophic. But if you've got the right conditions for them,
Speaker 3: kind of unlimited food, the right physical space, they're pretty
Speaker 3: easy to deal with in the lab. But we have
Speaker 3: to cows them separately, and that's different than other birds because, yeah,
Speaker 3: they're so aggressive. They they would exclude each other from feeding,
Speaker 3: for example, and their bills can be a weapon. So
Speaker 3: when when they're kind of housed in captivity, we keep
Speaker 3: each individual on its own and you don't see it
Speaker 3: that often in the wild. But but if you have
Speaker 3: video footage, high speed video footage of birds interacting and
Speaker 3: fighting at a feeder, you'll see how that bill is
Speaker 3: really like a long dagger, and that they're they're facing off,
Speaker 3: they're making sure they orient their bills towards towards each other.
Speaker 3: You can imagine a collision with those long bills would
Speaker 3: be really catastrophic for an animal that only weighs two
Speaker 3: and a half grams.
Speaker 2: Oh wow, Yeah, that was going to be one of
Speaker 2: my questions, like what is the We see them chasing
Speaker 2: each other, like, what are they actually doing to each other?
Speaker 2: If they catch it, it's kind of it sounds like
Speaker 2: it's like a joust in a sense, right, yeah.
Speaker 3: And it's really hard for us to capture what that like,
Speaker 3: what are the consequences of that in the while the
Speaker 3: best examples we have are footage that people can capture
Speaker 3: at a feeder and when birds really get into it
Speaker 3: close to a feeder, what happens and you see them
Speaker 3: grabbing each other's feathers and using their bills to defend
Speaker 3: that space to displace another bird. And and there's still
Speaker 3: a lot of open research questions about you know exactly
Speaker 3: how like what what signals or outcomes are determining who
Speaker 3: wins those competitions and and that's an active area of
Speaker 3: work that we're studying now in my lab. But even
Speaker 3: in the lab, we'll see them rarely make physical contact
Speaker 3: with each other. So if one bird wants to displace
Speaker 3: another from a perch, sometimes they'll get into little scuffles
Speaker 3: where they're making contact, and I think at high speeds
Speaker 3: those kinds of scuffles would be really dangerous to both individuals.
Speaker 3: So it's a real game of chicken.
Speaker 2: Now, when you're studying hummingbirds, is it completely seasonal? Is
Speaker 2: it seasonal availability very much a part of this or
Speaker 2: do you have hummingbirds like in captivity that you can
Speaker 2: study year round.
Speaker 3: Yeah. So in my lab here in Oddwell, we're studying
Speaker 3: ruby started hummingbirds and they are migratory and so we've
Speaker 3: been catching birds here since the beginning of May, and
Speaker 3: we've got a group of males in the lab now
Speaker 3: that will release again prior to their autumn southward migration.
Speaker 3: So we're only working with them within the breeding season
Speaker 3: here and only studying the males, and remarkably many individuals,
Speaker 3: many of the migratory species, an individual humming bird will
Speaker 3: come back to the very same feeder. So one of
Speaker 3: the birds in my lab now is a bird that
Speaker 3: we caught and released on campus last year. Attached a
Speaker 3: little band to his leg with an identifying number, and
Speaker 3: he would have migrated all the way to Mexico, and
Speaker 3: then this spring, the first two weeks of May, like clockwork,
Speaker 3: he showed up at the exact same feeder. We captured
Speaker 3: him again this year. So it really is remarkable not
Speaker 3: only the physical feats that they do, but also they
Speaker 3: have remarkable memories and that's all part of their high
Speaker 3: metabolic rate. They need to know where those reliable food
Speaker 3: sources are. So this male were bethowted humming bird came
Speaker 3: back to the exact same feeder after this cross continental journey.
Speaker 2: That was going to be one of my follow up
Speaker 2: questions about the what's going on in the mind of
Speaker 2: a hummingbird, And it's because again, they just they're such
Speaker 2: drastically different creatures. They're living on this time frame, you know,
Speaker 2: that's so different from ours, and then vast distances in
Speaker 2: addition to vast speeds, so we have what else do
Speaker 2: we know about their about the way their little brains work.
Speaker 3: Yeah, it's really fascinating. So there's a lot of excellent
Speaker 3: research coming out of my co author, Doug Altruler's lab
Speaker 3: on how their brains work and how the visual system works.
Speaker 3: And we also have studies of their spatial memory. And
Speaker 3: so a really beautiful study from about twenty years ago
Speaker 3: now on a species of hummingbird that lives in the
Speaker 3: Rocky Mountains looked at their ability to learn flowers that
Speaker 3: change in nectar availability through time. So real flowers are
Speaker 3: not like feeders. Real flowers will be depleted and will
Speaker 3: replenish themselves over some seasonal period. And hummingbirds that have
Speaker 3: a territory with lots of flowers in them, they need
Speaker 3: to know where their next meal is coming from, and
Speaker 3: they're able to learn the locations of many flowers. As
Speaker 3: an example, this bird that came all the way back
Speaker 3: to my feeder from Mexico, he would have remembered other
Speaker 3: places along that route, we hypothesize. So what the researchers
Speaker 3: did in Alberta, Canada was create an experiment where they
Speaker 3: could track one male in the wild who had a
Speaker 3: territory and they had dynamic feeders in that territory that
Speaker 3: went on different time schedules. Maybe some feeders would replenish
Speaker 3: on five minute intervals, others on ten minute intervals, others
Speaker 3: on twenty minute intervals. And if a bird had multiple
Speaker 3: of those variable timed feeders available, would they be able
Speaker 3: to learn those different time schedules. They found that indeed
Speaker 3: they could. So not only can they remember where the
Speaker 3: food resources are, but they can keep track of multiple
Speaker 3: variable schedules within their territory, like all in their head, right,
Speaker 3: so they've got like a calendar in their head to
Speaker 3: determine where like which, which resources have food, where are
Speaker 3: they and when are they going to become profitable again?
Speaker 3: And their brains are really really small, remember, because their
Speaker 3: whole bodies are miniaturized, so their brains are much much
Speaker 3: smaller than the brains of other birds. So it's really
Speaker 3: quite incredible that they can do that.
Speaker 2: Yeah, I'm really impressed by their ability to map all
Speaker 2: that out. And then I feel a little I can't
Speaker 2: help but feel guilty by how like if I forget
Speaker 2: to refill the feeder or to change out the nectar
Speaker 2: and a feeder, I just now I'm going to feel
Speaker 2: even worse because I'm messing with their finely tuned like
Speaker 2: mental map of where all the flowers and the feeders are.
Speaker 3: Yeah, it is important if you're maintaining a Feeder's important
Speaker 3: to keep it going. But you know they're they're really
Speaker 3: resilient as well. They've been around for millions of years
Speaker 3: before we started providing feeders. And uh, and so the
Speaker 3: birds that are in your yard, they're in your neighborhood,
Speaker 3: they're going to have other food sources mapped out. So yeah,
Speaker 3: it's it's important, but it's unlikely to be catastrophic if
Speaker 3: one person, you know, forgets to refill their feeder. But
Speaker 3: what's also fascinating is that we're learning how those feeders
Speaker 3: are changing are causing contemporary evolution in hummingbirds. The species
Speaker 3: that we have on the east eastern North America here
Speaker 3: Ruby tharted humming birds. Their populations are doing quite well
Speaker 3: despite lots of threats that are that that humans are
Speaker 3: creating for other bird species, and probably a big part
Speaker 3: of that is humans providing food to them. On the
Speaker 3: west coast, the Enna's hummingbird is a species that has
Speaker 3: expanded its range, so it used to only live in
Speaker 3: kind of warmer states in the southwest of the US,
Speaker 3: and now we find that species and as humming bird
Speaker 3: as far north as Vancouver, Canada, where we conducted our research.
Speaker 3: They've expanded over the past century with people providing food,
Speaker 3: both ornamental flowers but also feeders, and we're learning that.
Speaker 3: There's a study that just came out this year. We're
Speaker 3: learning how providing feeders is causing measurable changes to the
Speaker 3: morphology of their beaks. Their beaks are changing in size
Speaker 3: as they've been expanding. So it's really really neat because
Speaker 3: beak shape evolution is kind of this classic case where
Speaker 3: that led Darwin to come to appreciate how natural selection works,
Speaker 3: and we humans are now causing that to happen on
Speaker 3: rapid timescale.
Speaker 2: Wow, so what sort of changes are taking place here?
Speaker 2: Are the beaks getting shorter longer?
Speaker 3: Yeah, so their beaks are getting longer to be able
Speaker 3: to extract food from feeders and their way. Researchers have
Speaker 3: been able to discover that is by measuring the beaks
Speaker 3: of museum specimens that were collected over the past century
Speaker 3: and kind of building up a time series of specimens
Speaker 3: from you know, one hundred years ago, fifty years ago
Speaker 3: to present.
Speaker 2: Wow, that's impressive. So you're spending all this time studying hummingbirds,
Speaker 2: do they retain their magic for you or do they
Speaker 2: become like just a little every day? Are they still exciting?
Speaker 3: They are still exciting. One of my favorite moments from
Speaker 3: going out into the field at the sites where we
Speaker 3: find our hummingbirds is getting to see courtship displays. Getting
Speaker 3: to see a male court a female and we throw
Speaker 3: a hummingbirds say do the shuttle display where they're zooming
Speaker 3: back and forth and they start, you know, with a
Speaker 3: small arc and they're flaring their colorful feathers in front
Speaker 3: of the female and their shuttle gets bigger and bigger,
Speaker 3: faster and faster. It's still really magical, even after handling
Speaker 3: lots of hummingbirds in the lab. And the other thing
Speaker 3: I find really exciting about them is seeing their behavior
Speaker 3: slowed down. When if you capture interactions with high speed
Speaker 3: video and then watch them at slow speed, it really
Speaker 3: looks like you get an even greater appreciation for what
Speaker 3: they can do because it looks like they're swimming in
Speaker 3: the air. You know, it looks like like they're moving
Speaker 3: in the air as definitely as we do kind of
Speaker 3: on the ground, and you get a real impression for
Speaker 3: things that they can do that you know, they just
Speaker 3: whiz by you when you're seeing it in real life,
Speaker 3: but there's a lot happening there.
Speaker 2: Yeah, I know just from this was several years back,
Speaker 2: but I went with my family to Costa Rica and
Speaker 2: we got to see some hummingbirds there at some feeders,
Speaker 2: and just with whatever sort of iPhone we had at
Speaker 2: the time, you know, you could take to take pretty
Speaker 2: decent video and slow it down and gets this enhanced
Speaker 2: appreciation for what they were doing. And so I can
Speaker 2: only imagine what's possible a with today's iPhones and smartphones
Speaker 2: and with like serious of film film equipment.
Speaker 3: Yeah, yeah, that's right. And Costa Rica has like a
Speaker 3: huge diversity of species, and different locations that you'll visit
Speaker 3: will have different species. And that's another question that continues
Speaker 3: to fascinate me. The smallest hummingbirds we have are just
Speaker 3: you know, two grams, which is the mass of a penny.
Speaker 2: Wow.
Speaker 3: And then the largest species we have is twenty grams.
Speaker 3: That's ten times bigger. And then we've got three hundred
Speaker 3: and sixty six species that span that range. Most of
Speaker 3: them kind of between the two to ten size, which
Speaker 3: is still a big range. Why is it that there's
Speaker 3: so many different ways to be a hummingbird? How do
Speaker 3: all of these like this one kind of overall strategy,
Speaker 3: How does it lead to this diversification? And how do
Speaker 3: they all coexist? Is another really fascinating question.
Speaker 2: All right, well, Roslin, thanks for coming on the show
Speaker 2: and chatting with me today about hummingbirds.
Speaker 3: Thank you very much.
Speaker 2: Thanks once again to Rosalind Dacon for taking time out
Speaker 2: of her day to chat with me again. The paper
Speaker 2: is turning trade offs hummingbird power reserves are used to
Speaker 2: decrease turning radius or increase turning velocity out now in
Speaker 2: the Journal of Zoology, and you can learn more about
Speaker 2: her work with the Dynamic Behavior Lab by visiting our
Speaker 2: website at Rosalindacin dot com. This's r O s l
Speaker 2: y N DA ki N dot com. Just a reminder
Speaker 2: to everyone out there, The Stuff to Blow Your Mind
Speaker 2: is primarily a science and culture podcast with core episodes
Speaker 2: on Tuesdays and Thursdays, but on Fridays we set aside
Speaker 2: most serious concerns to just talk about a weird film
Speaker 2: on Weird House Cinema. Thanks as always to the excellent
Speaker 2: JJ Possway for producing the show, and if you would
Speaker 2: like to reach out to us, you can email us
Speaker 2: at contact at stuff to Blow your Mind dot com.
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