Thumbnail image David Monroy Rengifo | Macaulay Library

[Ian Owens] Welcome to the 2023 Mundinger Lecture. It gives me great pleasure to say that and to have so many of you in the room here. And I know that we’ve got many hundreds actually online. As we experienced last year, coming out of the pandemic, many very terrible things. But one thing that has really taken off is the number of people that will now join these sorts of lectures if they’re available.

So welcome everyone in the room. I can see people from lots of different departments here. So that’s wonderful. And yeah, hello to everybody online.

Before we start the formal proceedings, let me begin with a Land Acknowledgment. Cornell University is located on the traditional homelands of the Gayogohó:nǫˀ, the Cayuga Nation. The Gayogohó:nǫˀ are members of the Haudenosaunee Confederacy, an alliance of six sovereign nations with a historic and contemporary presence on this land. Confederacy precedes the establishment of Cornell University, New York State, and indeed the United States of America.

We acknowledge the painful history of Gayogohó:nǫˀ dispossession and honor the ongoing connection between the Gayogohó:nǫˀ people, past and present, to these lands and waters. Thank you very much.

So I suspect that most of what the Cornell Lab of Ornithology is. I hope you do. There might be questions afterwards. So we’re a group that tries to bring together technology, science, education, and mass public participation to get people interested in birds and biodiversity, the science that underlies that and their conservation.

So for us, public lectures like this are fit right into the center of that because it’s an opportunity typically to hear some really interesting cutting edge work, but put in a broader context and having lots of people be able to ask questions around that. So we really love these public lectures even though it’s been a few years since we’ve been able to do them. We had one last year. But it’s really great to be back here.

Now this one is a particularly special one because this one, Mundinger Lecture, honors Paul C Mundinger who you’re going to learn more about in the next few minutes. A famous researcher with a strong connection here to Cornell. I’m particularly pleased that tonight, we have Mary Mundinger with us, Paul’s wife. Do you want to give us a wave, Mary? And we also have Paul’s daughter, Elizabeth, with us who will say a few words about her father in a minute.

Before I give Elizabeth chance to do that, I’d like to actually read out a few comments that we’ve got about Paul and about the connection to this lecture and to Cornell, which include some comments from Paul’s son, Thomas. Just give me a few moments. I’ll just read these out because I thought they framed Paul and his work and the relationship with this lecture very well.

So Paul Mundinger earned his PhD at Cornell in 1967. Spent most of his career as a professor at Queens University in New York, studying the evolution of song and song learning in Finches. He was a famous professor.

“In a word, the goal of this lectureship, from my family’s point of view, is to aspire,” says his son, Thomas, who is a diabetes researcher at the University of Washington. “My dad was passionate about his work in teaching people. But what he was really attracted to was getting the students to take in information and run with it, to aspire to apply their work to improving the human condition.” So much broader than what you might think when you think about Finches initially.

Paul Mundinger formed a strong attachment to the Cornell Lab during his PhD work when he spent many hours in what was then the Library of Natural Sounds, what we would now call the Macaulay Library. Spending so much time there that Thomas says, his only clear recollection of Ithaca as a four-year-old in the 1960s is of looking out over Sapsucker pond through a spotting scope set up in what would have been then the old observatory.

Today, the Macaulay Library just last week received its 2,000,000th record of a sound. Amazing achievement since these days. And that includes over 1,500 of Paul Mundinger’s original audio recordings that can be played online. So there’s that very deep connection with the lab as well as the broad concept.

Going back to Thomas’s comments, “My dad got his doctorate at Cornell and he liked to talk about the importance of peers to students. Not necessarily your teacher or a mentor, but your peers,” Thomas recalls. “That’s why this lectureship is important to us and would have been important to him. It’s outside your normal discipline, it’s your choice to show up this evening, and then you go home from a talk like this, and you talk to your roommates, inspiring people to grow. It’s that word, “aspire.” Now that you’ve got the basics, go out and contribute to it.” Thomas says of his father’s attitude towards his students, “He liked the fledglings. He liked to see them take off.”

So I just thought that was a lovely kind of collection of thoughts about what he thought in his life and how that relates to why this is an undergraduate lecture and why it’s intended to inspire you to go off and do great things in life with what you learn here. OK, that’s enough from let. Me now introduce Elizabeth Carson, as I said, Paul’s daughter, who will say a few words about her father before we continue.

[Elizabeth Carson] Hello, everybody. I’m Elizabeth Carson. He just talked about my brother Tom. And now I’m going to tell you a little bit about this lecture is in honor of my father, Dr. Paul Mundinger.

He got his PhD in evolutionary biology here at Cornell. And I really think it’s great that we look at birds here with evolution because they really play an important role. I mean, they’ve been around since the dinosaurs. Unlike other animals, they’ve been able to fly to other continents and to fly to other islands where they intermingle and change and do things differently while other animals were isolated. So it’s really a great research animal to look at birds and what they’ve done over time.

And birds have been very important to my family. I still remember my father going out and doing the recordings with these huge umbrella-like tape recorder, microphone, and going up into the trees, and people looking at him like, is that a weapon, and really worry that it was some sort of gun or something. And he’s like, no, I’m just recording the birds.

And growing up, I was able to feed some of the baby birds that he was raising for research. I also joined him in studying some of the sonograms he did. He was raising house finches, but putting these house finches to be raised by canaries to see if they would sing the song of the canary or would they sing the song of the house finch, how much of it is genetic, how much of it is environment and language and communication. Really interesting things.

And I love that there are hundreds and hundreds– I guess 1,500 tapes that he’s made here at the Lab of Ornithology. And if you go in and listen to them, which you can do online, you can hear his voice, which pulls at my heartstrings because I miss him terribly. But it’s great that all those tapes are there.

And this interest in birds has even been passed down to my daughter. She’s currently in vet school. She interned at the largest wildlife animal hospital in the nation this summer. And she was in the bird department because she really likes birds more than any of the other animals. So this interest has really been passed down the generations, which is wonderful.

And I’m really looking forward to hearing from Dr. Regina Macedo and hearing about what’s happened with the Blue-black Grassquit. It’s just great to see that research and what everybody’s doing and to really think about what it means in your life and how things may change for you, hearing about these interesting things. Thank you very much.


[Ian Owens] Thank you, Elizabeth. Really nice to hear from you directly about your father and those family connections. OK, now let me introduce somebody that most of you in the room will already know, Mike Webster, Professor Mike Webster. He’s the angle professor in the Department of Neurobiology and Behavior. And he will introduce today’s speaker. Over to you, Mike.

[Mike Webster] Great. Thanks, Ian. Thanks, Elizabeth and Mary. Elizabeth, those are really nice thoughts. So thanks for sharing those.

It is my great pleasure today to be able to introduce our speaker, Regina Macedo, who I’m happy to say has been a friend of mine for many years. And just before I call Regina up, I want to give just a little bit of a glimpse of some of who she is and what she is so you have an idea of who you’re hearing from. So Regina is currently on the faculty at the Universidade de Brasilia in Brazil and that actually is where she started her academic career, more or less. She got her undergraduate degree from that same University, then went off to Oklahoma where she got her PhD in 1991, studying animal behavior, and then worked her way back down to Brasilia to take up her position where she is now.

Regina is an incredibly accomplished researcher. She has well over 100 peer reviewed publications, she’s authored or co-edited five different books on the behavior of neotropical animals, in particular neotropical birds, she has been an associate editor for several scientific journals herself and also served for several years as the president of the Animal Behavior Society, which is the largest professional society of people who do research in animal behavior. And because of all of those accomplishments, she’s received several different awards from various societies. She is a fellow of the Animal Behavior Society and also of the American Ornithological Society.

In 2020, the American Ornithological Society bestowed upon her the William Brewster Memorial Award which is an award that is given annually to the author or co-authors of the most meritorious body of work on birds of the Western hemisphere published during the preceding 10 years. So it’s AOS’s highest distinction for research. In 2021, she was awarded the Alexander F Sketch medal from the Association of Field Ornithologists. And that’s an award that recognizes career accomplishments of people who have done extensive research and have greatly contributed to our understanding of the life histories of neotropical birds.

So Regina’s done a lot as a researcher. But I have to say, because I know many of her students personally, that what she’s accomplished as a researcher pales in comparison to what she’s done as a mentor. She’s been the mentor for– I counted on her CV– 21 PhD students and 33 different master’s students and countless numbers of undergraduates, many of whom have gone on to great careers in research themselves.

And I think it’s no small exaggeration at all to say that the Regina’s really spearheaded the science of animal behavior in Brazil and other parts of Latin America. And I say that because she really has, at most, one degree of separation for most of the people in South America who are doing this sort of research. Many of them were her students. And those who weren’t directly her students are students of her students now. And so it’s really been amazing to watch that happen over the years and see so many people with those strong connections to Regina, who are out there doing amazing work themselves these days.

I guess I also want to mention that Regina has several strong connections with Cornell like Paul Mundinger. She has some very strong connections with Cornell. She has sent several of her own students here for training in bioacoustics and genetics so they can complete their own projects and become part of the Cornell and Lab of Ornithology family. She helped the Lab of Ornithology conduct several different sound recording and bioacoustic workshops in Brazil. She spent a sabbatical here in 2019, so is familiar with Ithaca and Cornell through that.

And so I’m really delighted to be able to welcome Regina back to Ithaca. And before I call her up though, I also want to point out that all the science stuff aside, she’s also an incredible painter. And I’m proud to say I have three of her paintings hanging in my house. So with that, please join me in welcoming Regina Macedo back to Ithaca as this year’s Paul C. Mundinger lecturer.


[Dr. Regina Macedo] Can you guys hear me? OK, good. First of all, thank you, Mike. That was an awesome introduction. Amazing. You made me sound so good. Just thank you.

I’m really, really pleased to be here. It’s such an honor to have been invited to present this talk for the Mundinger lectureship. I’m so excited to be back here in Cornell. And they tell me this is the most beautiful time of the year. And I can readily believe that it’s been incredibly wonderful to drive up from New York to Ithaca just to see all of the beautiful trees. Not only that, but it appears that the weather has really been very collaborative this last week apparently. It’s welcomed me back here. So I’m very happy for that.

I haven’t spoken English on a day to day basis for the last four years, I guess, since COVID. But I’ve been able to brush up on it the last two days. So hopefully, I won’t stumble too much over my English. So if I do, forgive me. Anyway, OK, so if you guys have anything, if I do something here that you don’t understand or whatever, just go ahead and say it, if I mess up with the slides. But I think it should be OK.

But before I start, I’d like to tell you a little bit about my connection with Cornell aside from what Mike talked about. Some 30 years ago, when I was starting out as a researcher in Brazil, and I was working on a little known bird at that time, the guira cuckoo. And I sent off one of my first papers to the Journal of field ornithology and it was just sort of like a short note. And of course, without my knowing it, it was sent off for review to none other than Dr. Steve Emlen who I’m sure all of you know. Of course, I didn’t know it at the time, but I was very surprised.

A few days later, I got a personal letter from Steve Emlen. And at that time, there was no email. So this came over regular mail. And this is the letter and then a picture of myself with Steve Emlen many years afterwards. In this letter, he encouraged me to continue my research with the guira cuckoo. He also sent me several of his reprints and just was very, very, very incredibly nice actually.

And I was so amazed that this world known researcher, Dr. Steve Emlen from Cornell, which is one of the best universities in the world, had taken of his time to write to an unknown researcher in the middle of Brazil, that I was so taken with this that I kept this letter all over the last 30 years. And so here it is. And then many years later, I met none other than somebody that you guys also know very well, Mike Webster. And here he is in two very special moments being Mike, Mike being Mike.

I’m in a ski lift with him at one point, and he was obviously being Mike the way I know him. And also this is when he met my dog down in Brazil. And Mike can tell you about that if you ask him. anyway, and after that, beyond our friendship, we established a really great collaboration. And so Mike came down to Brazil a few times like he said for the workshop. I sent several students up here to Cornell. And so this has been a really wonderful collaboration.

OK, so I’d like to tell you a little bit about the story that I’m going to tell you about. Like most other, biological research obviously rests upon Darwin’s theory in general. But particularly, what I like specifically in terms of Darwin’s theory is the intersection between natural selection and sexual selection, is the intersection between these two forces sometimes shapes particular behaviors and ornamentation and sorts of displays that I became interested in. So it’s the interface between these two forces that I became interested in.

OK, something– so I want to tell you how I started my work with the Blue-black Grassquit. And that was over 20 some years ago. And like I said, I was working with the guira cuckoos at that time. And they nest in very tall trees, 15 to 20 meter trees.

And at one point, I was climbing up the tree to look at a nest, and I decided to take a break, and I sat on a branch. And as I sat there, I saw this little black speck moving in the distance on a fence. I whipped out my binoculars, I looked at it. And sure enough, it was a Blue-black Grassquit. Not surprising because this is a very common bird in the region where I lived.

And as I looked at this bird, I thought to myself, well, it’s such a cool little bird, but surely it’s been looked at by so many researchers before because it has this incredible displaying behavior. So I went on to look at the guira cuckoo nest and forgot all about this. Then a few days later, I remembered this moment, and I decided to go and look up some of the research that might have been done about this bird.

And when I looked up at this research, I found actually very, very little that had been done about this bird. And here is one of these publications that I found. And this publication in 1985, I believe– yep– there was a description where Weber said, “Each time, I found many grassquits of displaying in a dense congregation unlike anything described today. In some ways, this congregation resembled a lek.”

But in the same publication, he also mentioned the fact that there were other researchers that had found this to be a territorial bird, a few other publications. And so I looked them up and here’s another one by Murray. And he also mentioned Miller and Davis who’d observed in short observations actually. They’d observed Blue-black Grassquit males feeding the nestlings. And so they assumed this was a territorial bird.

But these were all very superficial, very short descriptions because these researchers came to the neotropics for brief amounts of time. And so they only had these very superficial descriptions. And that’s when I said to myself, you know what, this is such a cool bird, I really would like to study this bird for several reasons, but particularly the fact that they nest like only about 40 or 50cm off the ground sounded like a very attractive option to me at that time. And so I said, hey, I’ll start looking into this.

So before I go on, I’d like to say that this research conducted over the last 25 years was done with a lot of help and particularly the students that I had in my lab over the last 20 some years that worked on several facets of the Blue-black Grassquit project. So here are their names and here are their faces. And in addition to them, I also had some really wonderful collaborators in many parts of the world.

And so here on the left-hand side, Diego Gil from Spain and the late Jeff Graves from Scotland. On the right-hand side, Mike Webster whom you all know, Rui Oliveira from Portugal, and also Jeff Podos from quite nearby, from the University of Massachusetts in Amherst. So all of these researchers worked in some aspect of this research over the years.

So let me introduce you now to a very special little bird that I’ve enjoyed over the last many years. So like I said, this is a neotropical bird. Its range extends from around Mexico to Southern Brazil and also Argentina. So it’s a well known bird over there. They’re highly dimorphic.

So you can see here– let’s see if I can make sure that I point– yeah. So the males, you can see, acquire this black plumage. This is previous to the breeding season and it’s a glossy black plumage. And the females have a cryptic gray plumage. They’re socially monogamous.

And so very early on in our research, we found that indeed, the males defended their territories and both of them constructed nests and so on. So they’re socially monogamous. And the fact is their territories are so incredibly small, only around 13 to about 70 square meters because they aggregate these territories. That’s why people assume they might be a lekking species. Although, we quickly found out that wasn’t the case.

So like I said, they’re socially monogamous. And some people here might have seen grassquits down in Brazil whenever they’ve been there. They’re very conspicuous birds, at least the males are. They’re socially monogamous.

But in the region where I work in Central Brazil, the males arrive first. So they don’t live there year round. They migrate, we assume And probably with eBird, you can all probably find out that they migrate there, we assume, from Northern South America, from the Amazon. And they arrive around November, December.

And the males arrive first. They start doing their leaping display and set up their small territories. And then the females arrive a few days later. Now they both build a nest together. The female lays her eggs, two to three eggs usually. And only the females incubate the eggs.

And then about 10 days later, the nestlings hatch. So just the female incubates. And both parents feed the nestlings and it’s pretty equal parental investment. Both males and females care for the nestlings. And then about 10 days later after hatching, the nestlings fledge.

Now one of the curious things that we noted early on that despite investing so heavily in the parental duties, throughout the whole nesting cycle, the males continue doing their leaping display. So that was something that was curious to me right from the beginning. So the other curious thing that I thought was that despite the social monogamy, I was very suspicious of how highly ornamented the males were.

So here, you can see the transition. They arrive sometimes in Central Brazil with this sort of mottled gray and black plumage, and then the males change their plumage completely to the black, completely black sort of iridescent plumage. Now not all males acquire the complete black plumage. Sometimes you’ll see males that don’t acquire the complete plumage.

And the other interesting thing about it that people might not think is very important is the fact that they have these white underwing patches. And you might think, well, you don’t even see these white patches, the bird is perched there you don’t see the white patches, except for the fact that when the male leaps up, you really do see the white patch because it’s sort of like a white blur that you see when it’s leaping. And so for those reasons, I thought, well, this might be something important, the white patch in itself. But let me show you a little bit about what the display looks like.

So this is what you would see if you looked out in the field. And I could ask you, well, what did you see really, right? When you look out in the field, it’s sort of black popcorn popping up and down. And, well, yeah. And so what else?

So we couldn’t say much about it, except for the fact that we finally got some good funding, and we were able to obtain some good video equipment, and we were able to film them and then slowed down the sleeping behavior so we could see what they were actually doing. So I’ll show you what they were doing now, and I’m going to ask you questions afterwards. So you pay attention, what is it that they’re doing. OK, let’s see if I can get this to– no. There it goes. OK, so here it goes.

So what is it that they did? I mean, could you tell exactly what they did? So if I ask you how many times did these birds, how many times they beat their wings, when do they start singing, what was their body position like– these are all important factors when you look at a display.

So if you look at it again, you’ll notice, first of all, that it’s like about eight wing beats and that at the top of the leap, they tilt their body downward so their beak is pointing downwards. And they actually start singing at the top of the leap. And if you’re close enough to these birds, you’ll notice you can actually hear it. They clap their wings behind their back, and you can actually hear that sound.

So all of these things became important and it’s something that we call the multimodal signal because they’re transmitting several kinds of information. So they have the iridescent coloration, they’re beating their wings in a certain way, they’re flashing those white patches beneath their wings, and they’re also singing. So it’s sort of a really acrobatic leap, quite athletic. I saw how difficult and also how incredibly beautiful that was the thing.

So we started asking questions about the whole bird biology of the species and the reasons why they do these multimodal signaling leaps and what does it all mean in terms of the mating behavior. So in terms of natural selection, we asked questions that had to do with a lot of things. But here I brought some information about two things primarily, predation and how it might affect some of these things, and also we chose– I chose actually one aspect that we studied concerning their habitat to look at. And then relative to female choice. So this is the intersection that I was saying between natural selection and sexual selection.

So here, I wanted to tell you a little bit about what we did relative to female choice in terms of what sorts of attributes might females be using when they select a male as a mate. So our field site is located in Central Brazil. We work in what we call the Cerrado biome, which is a tropical savanna. And we have two field sites.

One of them is located inside the University itself. So it’s a patch of savanna within an urban matrix. And the other field site, we set it up in the research farm that our University has, about 40 away from Brasilia. It’s an abandoned Orchard that we use, and we set up a grid over there.

Relative to our methodology– now most of you here are probably very familiar with these methods. These are the typical field methods that people use when they work with birds. So we were using this netting and then banding the birds with aluminum bands, normally numbered bands and colored plastic bands. We were taking several types of morphological measurements. Among these, we use the mass of the bird divided by the length of the tarsus to determine a condition index, which is basically how much fat the bird has deposited and can use as energy.

We did genetic analyzes to determine paternity, and we also did a lot of behavioral observations, and we made recordings. So we recorded the male display, the male singing, we monitor the birds throughout the breeding season to look at territorial occupation, we also looked at parental investment at the nests. So the one thing that called our attention immediately was the problem with predation. I think you all have a saying here– I learned many different sayings while I was here in the United States. One of them was supposedly, if life gives you lemons, you’re supposed to make lemonade. People seem to say that quite a lot.

Well, the lemonade that we made and the lemons that we had concerned predation, very, very high levels of predation. And it was an obstacle until we realized that we should actually study predation to see what was going on and as an example. So in our 2013 breeding season for example, we had 148 nests. But of these, only about 16% of the chicks survived, quite low. So predation was over 80%.

So you might think that’s a really bad thing. But on the other hand, if you look at it from another angle, it might be really interesting thing. So this is what a typical predation event looked like. So what you’ll see coming to the nest is a smooth-billed anis and it grabs the chick by the neck and goes off with the chick. And like in most nests, within a few minutes, it would come back and grab the second nestling, and then the third nestling if there was a third nestling.

So you’d think that a nest that is only like about, oh, I don’t know, 40 off the ground, the worst predators might be snakes or rodents or whatever. But no, the worst predators that we had in that area were avian predators. And so among them, I’d say smooth-billed anis and my previous bird that I worked with, the guira cuckoos, and the curl-crested jays.

So we thought about it for a while, and we thought, well, how do these birds actually find the nests because they’re really cryptic. You look through the field. You have to find the nests are terribly small, hidden among the bushes. And then we thought, well, they must find the nests the same way we find the nests.

And how is it that we find the nest? Well, we look out in the field primarily. And where we see a male leaping, that is where the nest is going to be. And sure enough, if we go there where the male is leaping, we look around, we find a nest. So they’re not that hard to find.

So we figured, yeah, yeah, that’s how predators find the nest. But we can’t just say that. So we decided to do a little experiment to find out how these predators were actually finding nests and what was going on.

So we designed a very simple experiment in the field. And what we did is we set up half of the nests. We have artificial nests set up with two quail eggs. We set those up where males were displaying, but which hadn’t yet obtained a mate. So they didn’t have any nests in their territories. So we set these nests there. And for the control, we set up the same types of nests in similar habitats, but no displaying male.

So obviously, the hypothesis here was that, well, there are going to be finding the nests much more fast or in a greater proportion those nests that were associated with males. And well, sure enough, we did find that, which was kind of nice because not often you get the results that you’re expecting. But here, you can see the nest that didn’t have any male associated with them. So we conducted these experiments in three trials. So 28th of January, 19th of February, and 12th of March, the breeding season.

So you can see that these nests had almost 100% survival through the breeding season. But the nests that were associated with displaying males had quite different survivorship. So all of them were lower than the ones that didn’t have a male associated with them.

But something that we didn’t expect, which was quite interesting as it turns out, was that the survivorship of these nests declined throughout the breeding season. So here, what we thought was happening– and this is, again, another hypothesis which we would have to go out in the field and test it in some different way– is that these predators are actually learning to make this association through the field season, not only with our nests, the artificial ones, but with the real nests. They’re learning that if they look for this playing male, well, sure enough, they’re going to be able to find a nice meal, and that’s what was going on.

So based on these observations initially of predation, we thought, well, there are other things related to predation that might be really interesting for us to find out. And one of them had to do with predation risk and the fact that they have such accentuated dimorphism. And we assume that because predation risk could interact with the fact that they’re sexually dimorphic, and that might have an effect with how parental behavior evolved.

So we assumed basically that males, because they’re so colorful against the vegetation and they do this leaping behavior, they represent a very high predation risk for the nests and the nestlings whereas females, with their cryptic plumage, well, they represent a smaller predation risk. So we decided to go ahead and test this as well. So we did another experiment on the field, also very simple design.

And what we had here, experimental design, this time with real nests, on the fifth day after nestlings hatched. And we set up recordings, two types of recordings. For the experimental trials, we used a Sayaca tanager recordings. And a Sayaca tanager represents absolutely no risk to the nestlings. And then for the predator treatment, we use recordings of the guira cuckoo. And we set up these so that we had 20 nests submitted to each type of treatment and for two hours for each treatment.

And as predictor variables here, we use predation risk that is either zero risk or a lot of risk considering the guira cuckoos and the sex of the parent, either male or female. And for the response variables, we had eight types of parental behaviors at the nest that we looked at. So let me show you a little bit about how this turns out.

So what you’ll see here are two types of graphs. Now the graphs in green are associated with females, the graphs in blue with the males. And within each graph, you have, on the left-hand side, you have the control, on the right-hand side, you have the predator treatment. So you can see from the lines that connect the dots how that behavior either declined or increased.

So in this case over here, for example, the behavior that we had is latency to visit the nest after the predator treatment. And what we found is that females come back to the nest a lot quicker than males come back to the nest after being exposed to the predator treatment. So this was one difference we found in the types of behaviors expressed by the parents.

Now another difference that we found was the time spent brooding. And we found that females, after being exposed to the predator treatment, they increased the time that they spent brooding whereas males decreased the time that they spent brooding. So another difference of that type.

Now one other behavior, but in this case– I’m just going to show you a few of them. But in this case, we found that both males and females had the same response. So in terms of the feeding visits to the nestlings, both parents decrease the frequency of their visits to the nest. So we found several differences.

But one behavior that we found that was just for the male and was really sort of interesting– in our observations, because we were filming these, we found that the males frequently had a very odd behavior. When they fed the nestlings, after feeding the nestlings, they would actually use a nest rim to conduct their leaping display. So they use the nest as a perch. So don’t ask me why they do such stupid behavior, but they do.

And so we thought that was really wild. But we found that once they were exposed to the predator treatment, they were 200% less likely to conduct the leap. So maybe they’re less sexy when they don’t leap, but at least their offspring might survive a little bit more.

So I’m going to jump off to something else now. I’m going to talk to you a little bit about the habitat. Now in terms of something in the habitat that we looked at. So notice that the grassquit is doing his leaping display and singing. We call that the complete display.

But he might also not leap. So he might just conduct the singing behavior and not leap. And we call that the incomplete display. Nonetheless, whatever he’s doing, a grassquit like that, he wants to be heard and he wants to be seen, obviously. And when you look at the type of habitat that these grassquits live in, the name grassquit says it all. They live in a grassy habitat.

So it has lots of grass, small shrubs, and small trees. But one other thing that this type of habitat has that people don’t really pay much attention to is the abundance of sunlight. It’s very open habitat. And these birds are exposed to a lot of sunlight.

So why would that be important? So what, there’s a lot of sunlight. Well, we thought to ourselves, this might be really important because of signal conspicuousness. The quality of a signal should vary quite a lot depending on ambient light. So we thought to ourselves, well, you have here the interplay between ambient light, the reflectance spectra of the color itself that the animal has, and then the movement of the animal. All of these things contribute to how well the signal is transmitted.

And so if you think, for example, on an incredibly beautiful, colorful butterfly, in a cloudy day, well, all its colors are muted, its signal cannot be transmitted as well. On the other hand, when the sun comes out, well, the butterfly signal– all the colors are incredibly bright and easily seen. So how important is that, for the signal to be well transmitted?

Well, we thought about that for a while, and we thought that signal conspicuousness in itself has some big costs because obviously, seeing those grassquit leaping, it has costs because it attracts predators. We never measure this, but we assume it’s energetically very costly to conduct these leaps. And also, there are trade offs in these ornaments and displays.

So while a male might attract a female by doing these displays, he also attracts predators. So there are costs in natural selection. So we thought that considering all of these costs that males should be smart, evolutionarily speaking, and that they should be really selective in when they do their displays. They should optimize the signal in those windows of time when that would be most important to decrease their costs. And we also thought, well, if we assume that they can do that, that would also indicate that they have a lot of plasticity in conducting, and they can be flexible in conducting these behaviors.

So we assumed then that direct sunlight increases the conspicuousness of the males because they have this iridescent plumage, and we made some predictions based on that. So we predicted that those males that were sitting under direct sunlight would increase the frequency of their leaps, and we also expected of the complete displays that they would be leaping and singing and then that when sunlight was not bathing these birds directly, they should decrease the leaping and just use the perched singing behavior. So they would decrease the cost associated with that.

So we went out in the field and we measured that. So we used periods of time of five minutes and measured sunlight bathing these birds in three points of time during the 5 minute intervals and looked at the frequency of the leaping during those periods of time. And we found out that sunlight incidence, bathing the bird directly increased the frequency of the leaps. So what you can see here is that in low sunlight, the incidence of the leaping is about four leaps per minute whereas in high sunlight incidence that is in complete sunlight over the bird, they can increase to about seven leaps per minute.

So they came out to doing what we had predicted in that regard, whereas when you look at the frequency of the incomplete leap, it’s a bit different. So you see that it peaks in the intermediate category of sunlight incidence, and then it goes down in the high category of sunlight incidence. What we think is happening here is that the males then transition into the leaping behavior when sunlight is bathing them directly. So based on this little experiment, we decided then that, well, yeah, iridescent coloration is important for these birds in some regard in that it’s a crucial part of their signal transmission in some way because they actually can modulate this according to the amount of sunlight that they have. And the other thing is that they can transition quite quickly from one behavior to the other, which shows that they have a lot of behavioral plasticity and flexibility.

OK, the other thing that I mentioned, of course, is that– sorry, you didn’t change it here. I mentioned that they want to be seen, but they also want to be heard. So I was not the first person to notice how cool this bird is in terms of singing when they’re leaping. Somebody else who you guys might have heard of, Mike Ryan, published this paper. And I thought was the coolest name here, the Acoustic Advantage of Getting High. I thought that was pretty cute.

And we were interested in the singing behavior as well. I can see some grins out there, yeah. That’s a cool name, isn’t it? Cute. Anyway, we were also interested in the singing behavior and what that might mean as part of the signal of the bird. But just to show you what this looks like– or not. There it is, OK.

Can you guys still hear me OK back there? Yeah? OK. So it’s a very short song. It’s only half a second in length and it’s only a single note. Although, there are these introductory elements over here. And it decreases from beginning to end of the song. And it goes from about 13khz to 2khz.

And though it’s so simple, we assume it’s very important because the bird is doing it within such a short span of time and while it’s sleeping. So certainly, it must be a difficult thing to do. And not only that, but one of the more interesting things that we also found is that each male has a unique song. And so it’s like a signature song.

So if you have the male and you have the sonogram, you can actually identify which bird you’re talking about because each one has a very specific song. So even a small field site like the one we had, there’s a lot of variety in the songs. So the question that we asked relative to female choice, now leaping into the– talking about leaping– leaping into the other part of the things that I was interested in is sexual selection. In terms of female choice, what sorts of attributes might the females be using to choose their mates and what might the consequences be for the mating system.

So like I said before, one of the things that I found very suspicious is because of this ornamentation– OK, so yeah, they’re socially monogamous. But they do have this leaping behavior, they have these plumage characteristics. And I guess we can explain that briefly here by looking at the operational sex ratio and how that interacts with mating systems.

So if you look at the operational sex ratio where it’s biased towards males, that is you have more males than females in the mating pool. And so there’s a lot of competition among males to access females. In those kinds of situations, you can expect males to acquire more ornamentation to exhibit more conspicuous courtship behaviors, and then you’d expect to have a polygynous mating system evolve.

Now if you have an operational sex ratio of approximately 1 to 1, well, you wouldn’t expect a lot of ornamentation, you would expect to see a monogamous mating system evolving. On the other hand, if you have an operational sex ratio, more a rarer type of thing that happens, but that’s biased toward females, you would expect a polyandrous mating system to occur. Nonetheless, you could expect sexual selection to also occur in monogamous species in some circumstances. And in the circumstances that we’re talking about, we’re talking about the fact that some males could still monopolize females in those situations by having extra pair fertilizations occurring.

And so in those situations, males would also be competing, but sort of undercover of a socially monogamous mating system. And then you could have, as a result of that, ornamentation evolving and also elaborate courtship behaviors. So that’s what I suspected from the very beginning by looking at these birds.

So we ask questions about how do females choose their mates in this species. And we thought, well, one possibility– females might be choosing males based on their ornaments of these were associated to indicate some direct benefits that female could acquire. So maybe males that were doing wild displays or whatever have better territories, better quality resources, something like that.

But we looked a lot more at the types of indirect benefits that females might be acquiring. So in that regard, we thought– this is called the good genes or the sexy son hypothesis. You might be familiar with that. But in this case, we would think that the displays might be indicating to females that a male might be really healthy, a lot of stamina. So in this case, maybe females would be looking at how high the males leap or the frequency of the leaps or even song parameters– frequency bandwidth of the songs, length of the songs, and so on.

So what did we expect? We wanted to go out and find some answers. Well, we thought, surely, females, well, what they want– they want males that are in better physical condition, that sing pretty songs, and hence, song parameters. And we thought that successful males then would be the ones that produced perhaps higher leaps or more frequent leaps or better quality songs. So I guess these are the expectations that, if you go out in the literature, this is the kind of thing that you would presume.

So we set out to measure these things. And here in this case, we measured parameters for 53 males where we had 65 video clips of both complete and incomplete displays. So for these males, we measured leap height, leap duration, rotation angle of the body– you might have noticed that the bird at the top of the leak had sort of– the leap, it sort of tilts its head down. Also, we looked at the body condition index, we had the song recordings for these males, and we also had paternity analysis for these males.

So we had 174 nests where we were able to genotype 131 nestlings. So a lot of people sometimes will ask me, well, how were you able to measure the leap parameters. It was just difficult, but not difficult. Let’s see– a lot of work, but not difficult.

So we superimposed the first image in the video clip with the image at the top of the leap when the bird was at the peak of the leap. And then we just drew lines from the bird’s feet. And then we measure it from the bird’s beak to this line where the feet were positioned, and then use the bird’s head length as the ruler to measure the height of the leap.

And then we drew lines that transected the bird from the beak to through the tail in both cases and the angle that was formed here was the angle of the leap. So we could measure that parameter as well. So everybody wants to know, what is it that females want. Well, guess we expect it to have, oh, yeah, we’ll find out wonderful straightforward answers. Well, not really. Sometimes it doesn’t come out that way.

But let me show you then what we got. So this table here, on the top part of the table are the maternity analysis for three years. And I’ll focus just on the totals in the red. And then on the bottom part, the paternity analysis. The first column here is just the number of chicks and then the number of extrapair chicks and the number of broods from which they came. And then on the right-hand side, broods where all of the chicks were extrapair, meaning that the social parents were feeding chicks that didn’t belong to them at all. And then mixed broods where you had both extrapair and within pair chicks and then the totals.

So here, for the totals, for the maternity analysis then, what we had is we had 127 chicks. Of these, seven did not belong to the female, social mother that was feeding those chicks. And all of these chicks came from 56 broods.

Now we had one brood where the two chicks did not belong to the social mom that was feeding them. We had four broods where there were mixed chicks, some didn’t belong to that female and some did, for a total of five broods. Now people might say, how can you have a female who’s actually feeding chicks that don’t belong to her.

That’s a phenomenon that you might also know called quasi parasitism. And what we think was happening was the male would mate with another female, and either he would show her where the nest was, or she would follow him back to the nest and parasitize the female at that nest. So at that nest, the social father was actually the genetic father, but the mom was not.

So it’s not a very high number here, just seven. It’s not very high. But in the case of the males, well, surprise, surprise, or maybe not very surprisingly, there was a very, very high rate of extrapair paternity. And so we had here 209 chicks overall. We had over 20% of those chicks that were extrapair, did not belong to the dad, the social dad that was feeding those chicks. And these chicks came from 95 broods.

Now we had 13 broods where none of the chicks belonged to the dad that was feeding them, and 17 with mixed paternity, and then total for 29. Now you’ll notice that along the three years, this varies quite a lot. So some years, there’s a high rate of extrapair paternity. Other years, there’s a low rate of extrapair paternity.

So with all of this, we were still interested in finding out what is it that females are looking for in these males. So what we found was interesting, though not what we expected, which is OK. For example, we found that males leaping higher were able to attract their social mates better than males that were leaping lower. But we found no relation between leap height and genetic reproductive success, which we were sort of expecting. Oh, well.

And the other thing that we found that– here, I’m just showing what we didn’t expect that we found. This is sort of a– so we found that longer songs are not better. And your guess is as good as mine why that might be the case. But we found that the probability of a male losing paternity in his nest increased the longer his songs were.

I’ll be interested in what your hypothesis is. You might have to explain that. So we ask something else. We ask whether social males were different from the males that were stealing paternity from that social male’s nest because we expected the males that were stealing paternity to be better. But no, no, we didn’t find that. We found that social males and the males that stole paternity from their nest were not different in any of the measurements that we made.

But we did find something that we didn’t expect. So we didn’t expect any of this either. But something else that we found that was quite interesting, but we never followed up on– we found that females with multiple matings have a higher body condition than females that are monogamous.

And we tend to focus a lot on what the males are like and what they’re doing and so on. And we tend to forget the importance of how the females are. And so this is something that we never followed up on. We found this and said, oh, this is our next research project. But I’m not going to be doing it. So you’re welcome to do it.

So another thing that came up was the trade offs in display parameters. And what we found is that males really cannot do it all. So we found that, for example, males that have a higher body condition index, they do leap higher. They can leap higher, and they also spend more time leaping. So it’s good for a male to pack in some fat to be able to do that.

So just to tie up some of the results that I had here to show you for these things that we asked, what is it that– just to summarize some of these things. So we found that, yeah, male display is a risky thing, and they attract predators. We found that increased predation risk changes parental behavior, particularly the male changes his behavior.

We found here, I’m showing you one habitat feature that we looked at that is something not very often looked at, but sunlight influences male display rate. We found that display height is important for these birds to obtain a social pair. And we found that males with a higher condition body index also have a higher leap, and they also leap more frequently. And finally, females that have multiple matings are in a better body condition than monogamous females.

So to tie it all together, the way that I look at this, I look at it in a sort of intuitive way. When you look at this intersection then between natural selection and sexual selection, so in natural selection, you might be thinking of the resources available to the animals or the force of predation and certain habitat elements. But if you look at any of these things in an isolated way– so if you only ask the question, what is it that females are interested and what are they looking for and you forget some of these other elements, I think you’re not going to get the answer that you expect because, for example, if a female chooses only a male that is particularly glossy or leaping higher or singing or whatever, she’s exposing her offspring to more danger. So the type of answer that you might get is not what you expect that things are more complex than you might imagine.

And I guess to my mind, also in a very intuitive way, I always think of nature and what I look at in these questions and answers that I get like that little children’s game– I don’t know what you call it here in the US. But you can never pull out one little twig and not expect everything to fall apart. So it’s a lot more complicated than most of us would imagine.

And with that– well, I don’t know what time I have and if I have time for questions. But I’d like to thank you all very much for coming and for listening and also for all my funding sources through the years, which were very generous. And that’s it. Thank you.


You’re calling it?

SPEAKER 1: Yeah. Go ahead.

AUDIENCE: Great talk. Very interesting. I’m not super familiar with the model system, but I kind of had some questions, just a few basic questions mostly about the size of the groups that they usually gather in. So we talk a lot about individual courtship interactions. And you mentioned that they were common. But are there huge groups of them that all come together, how do they make their decisions, is it something that is a little bit more complex than just spying the brightest male in the pack?

And then also, do the females have any vocalizations that the males might have to pick up on for a feedback system or when they’re making their mutual decision? Just kind of like maybe they don’t sing, but do they have any calls or something that are also important?

[Dr. Regina Macedo] OK, so these agglomerations that we see on the field is interesting because sometimes you’ll see they come in in very large flocks in my region anyway. They migrate into this region in very large flocks. And then these flocks start to break up. When I say very large flocks, like 50 to 100 birds just going through different parts of the habitat. And then they start to break off in smaller groups.

And finally, you get groups of maybe sometimes 30 birds or 40 birds in one specific area. So they’re all in their small territories cluster. And then you’ll have patches of habitat that don’t have any birds at all. And we don’t know exactly why they might not be in these types of habitats. And then you’ll run another group. You’ll find another group of 10 birds, 20 birds. So they’re like agglomerations of birds.

So why they agglomerate in these dense little clusters– I don’t know because we couldn’t find any differences in the habitats. But we suspect that there is advantages to being together in that sense because of predation perhaps. So that is one thing.

As for females, no, they don’t sing. They have quiet little tweaks now and then that you can hear. But they’re really not very conspicuous at all. They stay a lot on the ground. I’ve never seen them mate actually. So yeah, because they’re very inconspicuous. They’re on the ground. So, yeah.

AUDIENCE: Why do you think that the males display from these nests instead of other parts of their small territories? Or do you think that it’s an issue of their territories being so small that the tallest spot is the tallest spot and that’s also the best spot for a nest?

[Dr. Regina Macedo] No, the nests usually are not on the top of the bush. They’re usually a bit lower on. And to be honest, when I saw this, I was outraged. Why the heck are they leaping from their nests? Seems like really weird behavior.

Either they do it from the nest or right close by. They’ll hop to another little twig, and then they do the leap. I think they’re just dying to do their leap. There’s no good reason for why they would expose their nestlings to that, which is what I think. But then we did find that they decreased this very, very strongly if there’s a predator nearby. So it’s not the highest point in the territory at all. So I think that is not good behavior. It should have been eliminated by natural selection. Maybe it will be, but no.

SPEAKER 1: A question?

AUDIENCE: When you were doing the data analysis of here’s 53 males among the 65 video clips, I think it was, I guess other than changing from like the incomplete to the complete display, were able to find much in a way of variation within males for those different parameters like the rotation angle and stuff like that? Did it vary much within the male? Yeah.

[Dr. Regina Macedo] OK, so did everybody get the question? I’m not sure that I should repeat it or not. Whether there’s variation in these parameters of leaping display. No, they’re pretty consistent with their– it would be one thing to look at over time. Let’s say a male starts to display in the morning– and we didn’t look at that. But it would be interesting to find out whether, with time, they might decrease the leap height because they just get really tired.

So we were doing these measurements with– I don’t remember how many measurements that we use to conduct for each male we had the parameter, the average established, let’s say. But I would presume that along a day, they might decrease the leap height or the frequency just because they get tired. We’ve actually seen like a leaping male at one point. He sort of fell off the branch, and then he sort crept up again and sat there for a while, and then he started again. So maybe through the day, he would make a change. Wouldn’t you?


I mean, it seems like something that you could expect, yeah.

SPEAKER 1: Yes, please.

AUDIENCE: Kind of adding off the [INAUDIBLE] is there a reason known why they leave at all after already forming a pair?

[Dr. Regina Macedo] OK, what we think is that that’s the way he advertises for extra pair matings. Yeah, I think that that is probably the reason. He exposes his own nestlings, I think, to danger. But at the same time, he increases his chances of acquiring other mates.

So one of the things that we always think about– and this is like we end one project and there are so many questions that end up occurring that we can’t answer all of them in a lifetime. But one thing that occurs to me is that why in the world would males put up with a feeding so many offspring that don’t belong to him. It didn’t make a lot of sense to us in that way. But we think it has to do with predation.

So I’m still into thinking that predation is the driver of a lot of these things because if a male spreads out his genes across a huge expanse, he has some chances of some of his offspring surviving. And he feeds somebody else’s chicks, but somebody else is feeding his chicks somewhere else, maybe.

AUDIENCE: I have a question kind of building off of that. So you have these kind of nesting aggregations pretty small. And because it’s an avian predator that presumably– do you see anis with one set of 30 birds for instance, then continuously coming back to that group, or do they get fall off of one nest and then they’re like, oh, that’s it for [INAUDIBLE]

[Dr. Regina Macedo] Yeah. We don’t have the anis marked. So we don’t know whether it’s the same bird or not. But what we know is that they come back to the same nest until they’ve gobbled all of them up. And the other thing is when a flock of curl-crested jays comes through, we might as well call it quits because they go through, and they just get all the nestlings in that area. So we tended to try to drive off the curl-crested jays particularly when they showed up.

Yeah, but I don’t think they stay in the same area and pick on the same group. I think they find a nest, and they gobble it up, and then they go somewhere else. Yeah.

AUDIENCE: In areas of [INAUDIBLE] where there’s less disturbance that aren’t farms or like right next to the [INAUDIBLE], is the predation rate lower? Are there less of those cuckoos and anis and jays to predate the grassquits?

[Dr. Regina Macedo] Yeah, it is lower in these other areas that are more urban. Yeah, we seldom have the curl-crested jays in these urban areas. We do have guira cuckoos and anis. But the more disturbed it gets– I mean more disturbed in the sense of more urbanized, the fewer anis and guira cuckoos there are. There might be other predators that we haven’t really looked at, like more rodents maybe. But we find a lower degree of predation in these areas.

AUDIENCE: Then the follow up question would be in those less disturbed areas, if there’s less predation that’s mediating it, would you expect there to be a difference in the male strategy of extra pair, of seeking extra pair copulation?

[Dr. Regina Macedo] It might. I mean, we haven’t looked at it. But yeah, that’d be a nice hypothesis to follow up on. So I’m saying there are so many other questions that come up. And you think, oh, yeah, all these questions. And you say, well, 30 more years. Yeah, but it’s good. Cool.

AUDIENCE: I think that’s a [INAUDIBLE]. As you’re talking, I was thinking not only about your really wonderful body of work presented, but also that really wonderful body of students and former students that contributed to it over the years, many of whom, as Mike said earlier, have gone on to their own work. And I’m just curious, do you have any kind of standardized advice you give to people as they’re moving from your project to establish their own be successful in this line of research as early career scientists, doing this on their own in some other system?

[Dr. Regina Macedo] I’d ask Melanie here, a former student of mine who never came back home who’s a professor at SUNY. I think the students asked me this question I think yesterday, the graduate students. And I think that the biggest key to any kind of success is to absolutely love what you’re doing and to wake up every day really excited about what you’re doing.

And if you have that, I think that is the biggest thing to achieve success and to be happy. And if you’re not happy with what you’re doing, then you should be doing something else. That is primarily what I think. Yeah.

SPEAKER 1: That’s a beautiful place to stop right now. So please join me in thanking Regina one more time. Thank you.



End of transcript

The 2023 Paul C. Mundinger Distinguished Lectureship will be given by Regina Macedo, Associate Professor in the Department of Zoology at Brazil’s University of Brasilia.

The Blue-black Grassquit, a bird species native to South America, offers a fascinating window into avian behavior and evolutionary biology. Their eye-catching, leaping courtship dance is unique and distinctive. Dr. Regina Macedo has spent 25 years unraveling the intricacies of the Blue-black Grassquit and how the interplay between survival pressures and mate preferences molds behavior and appearances. Join us for this lecture as Dr. Macedo leads us through her work and explores how this unique neotropical bird enhances our understanding of bird biology. 

This lectureship was established in honor of the late Paul Mundinger, who received his Ph.D. in Evolutionary Biology from Cornell University.