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[APPLAUSE] GAIL PATRICELLI: It really is an honor to be here to give the Mundinger lecture. It's an absolute honor, and it's also particularly fun to come back to Cornell, which played such a formative role in my early career. There are so many people here on faculty and staff that have been incredibly supportive of me throughout my career. I feel like I've had a cheering squad on the sidelines as I've been going along in my career, and that's a pretty special thing to have.
And the graduate students and postdocs that I spent my time with here at Cornell are now my colleagues in faculty positions across the country. So it was a really amazing time to get to spend here as a postdoc. So it's great to be back.
And so with that, I hope our sound is working so that you can hear how fantastic these birds sound. But we'll see you when we get to the video. And so I'll just go ahead and get started. So let's see if I can do that.
OK, so Darwin's theory of natural selection is, of course, very powerful in explaining traits like camouflage coloration, like we see in the common [INAUDIBLE] up here. I don't know if you can see my pointer. There's a mother and her chick, and the common baron caterpillar hiding in plain sight at the front of the leaf, or the leaf tailed gecko. And so it's easy to understand the evolution of these kinds of traits by natural selection.
But of course it's more challenging to explain the evolution of traits like we see in the peacock, where these-- a lot of traits and behaviors seem to make the male an easy target for predators. And Darwin himself proposed the solution to this problem, which is his theory of sexual selection which proposes that these elaborate traits and behavior aid in reproduction and that the genes for these traits therefore spread in the population.
And one way that they can aid in reproduction is by female choice. So if females preferentially mate with the most ornamented of males. There's still a lot we don't know about sexual selection, even in the peacock, the poster child of sexual selection run amuck. But females do seem to prefer to mate with males that have more eye spots on their train.
And so in the most elaborately ornamented of species like the pea fowl and the sage grouse I'll tell you about today, males don't provide parental care to their young. So females take care of the young entirely on their own. So when the female is choosing her mate, she's not choosing a male that's going to be a better father in the sense of providing for the young. So anything she gets from the male is going to happen during the act of copulation.
So why does she bother meeting with the male that has the most eye spots on his train? And so now there's good evidence that females may benefit from being choosy if male display traits convey information about benefits that females may gain from their mate choice. And this can include genetic benefits, so beneficial genes for their offspring, and this may mean genes that encode for better immune system function, or simply for more attractive display traits. So sexier sons.
Or this may include direct benefits. So benefits that directly increase female fecundity or offspring survival. And because there's no male parental care in the species, that may simply mean avoiding parasite transmission during copulation. So avoiding STDs, basically.
And so females have something to gain from being choosy about their mates. Males certainly have something to gain from showing off because they can increase their mating success. But courtship doesn't just consist of the male unfurling his trait and the female counting the number of eye spots.
Courtships are often elaborate and dynamic, and they involve interaction between the male and the female. And courtships are often more like a negotiation than an advertisement. So to be successful from the male's perspective, males need to choose an appropriate location for courtship that's flattering to their plumage, and their sounds, and smells. They need to choose an appropriate partner for courtship that's the right species and the right age. And they need to approach that female without freaking her out and scaring her away. Anyone who's watched courtship in the wild or perhaps participated in courtship in the wild knows that that doesn't always play out that way.
And then they need to interact in a species-appropriate way once they get into courtship, which often involves chasing or counter positioning in very complex interactions. And they need to do this while deploying their effort wisely to produce the most attractive displays they can with the energy budget that they have available.
And in lekking species-- so species that gather together in the breeding season, and this includes pea fowl and sage grouse. They gather together and the males puff up and strut around, and the females visit to comparison shop for a mate. So this is where sexual selection is the most extreme.
And so this is one of our leks in Wyoming near my field site, and this has up to 300 or 400 birds in a very, very big year. Most years, it's not that big. But it's one of the few remaining enormous leks, and they likely were that big all the way across the range of the species at some-- at one time.
So in lekking species, this has to occur in an open-air marketplace. So all of these interactions of behaviors happen in this open-air marketplace of competing males. So the male is surrounded by his rivals and outside options. So he may be courting one female, but there's another female that's also available for courtship, and he has to decide who he's going to engage in courtship.
And so in order to do that, in order to make these decisions and also avoid predators-- there's often Golden Eagles that cruise in on the whole event here. And so males need to observe and respond to the flow of information on the lek in order to respond appropriately to all of these factors.
So these are complex tasks and males may differ in their tactical abilities. So Darwin's process of sexual selection may favor not just the evolution of elaborate display traits, like the peacock's train, but also tactical skills. So the social intelligence and social skills needed to negotiate effectively by adjusting their courtship behaviors in response to that social and environmental marketplace where courtship happens.
And few studies have examined the fitness consequences of variation among individuals in these courtship tactics because they're very difficult to measure. They require controlled experiments because you have two interacting parties and you want to know who's influencing who, and so to tease that apart is very challenging. And so, spoiler alert, that's where the robots come in. We'll talk about those in just a minute.
So today I'll talk about studies in my lab examining courtship tactics in greater sage grouse and how that basic curiosity-driven research informs conservation planning for this remarkable bird, and some of the more applied work that we do toward conservation of the species.
So why are we concerned about conservation with the sage grouse? Sage grouse populations have declined by about 95% since Lewis and Clark first described them for science, and they've lost about 56% of their habitat across their range. You can see that there's still very wide spread across the interior west of the US. And as a result, because there's so many states involved and there's so much economic activity that happens in sage grouse habitat, over the last few decades has been one of the biggest conservation efforts in US history for a single species. Arguably, the biggest in terms of money and number of agencies and groups that are involved in this conservation effort.
But there's still a great deal we don't know about what makes good sage grouse habitat and what facilitates successful reproduction in this species. So there's been a great deal of research, but there's still a lot we don't know. And it's highly variable across this wide range of this species. It may not be the same in each one of these states.
And so we've been using greater sage grouse as a model system to examine the fitness consequences of courtship tactics in the marketplace. And so today I'll tell you about a few experiments that we've done addressing these questions, and the first experiment is something that I talked about here at Cornell. I think it was eight years ago, something like that. But I'm going to assume that everybody forgot that, and I'm just going to give you-- because I know some of you weren't there. So I'm going to give you a brief reminder of that work because it lays the foundation for a lot of the work we've done subsequently.
And also tactics to respond to female signals. So tactics to produce an attractive display when there may be trade-offs between different components of the display and how to respond to female signals during courtship. And then I'll just briefly tell you about how that basic curiosity-driven research informs our conservation-focused research. Particularly right now, we're investigating the role of off-lek foraging behavior in determining on-lek success. So how the diet and habitat use influences reproduction on the lek. And also the impacts of noise pollution on lekking behavior. So how noise pollution may interfere with the communication by sound.
And so this research is done at our field site, our long-term field site in Lander, Wyoming, which is just east of the Wind River Range in a beautiful patch of the Rocky Mountains. And we stay up there for up to three months a year. We build our own little trailer park in the middle of nowhere. So we're right there next to the lek so we can access them-- I wouldn't say easily, but fairly relatively easily.
And we have had many field crews that have helped us do this work that I just want to briefly acknowledge. And this was a particularly epic year's photo. This was this year. So thank you to all of the many people who helped us do this work in the field.
And we are out there to study the sage grouse. And so this is a sage grouse lek. This is the peak day of breeding, and a few years ago at one of our bigger leks, and so these are all hens. And the peak breeding is just a day or two where almost all the meeting happens, and this is one of those days. So it's not normally this chaotic of a lek. These are all hens, and there's really only one male in this image that is getting any of the matings. Most of the other males aren't trying very hard. Fighting, strutting, and not having any luck.
So females visit the lek, comparison shop for a mate, and then take care of the young entirely on their own.
[SAGE GROUSE BURBLING]
And then a raptor came by.
And that guy figured it out, too, at some point. Yeah, there he goes.
OK. So what does this look like up close? So when you look at these birds up close, you can see they're very fancy chickens, here. So they have beautiful combs over their eyes that they can erect, they have filoplumes feathers on the back of their head, they have these stiff feathers on their chest that they can use to make a swishing sound of the wings across the feathers on the chest, and then that's followed by a vocalization.
[SAGE GROUSE BURBLING]
That's a bird.
[SAGE GROUSE BURBLING]
Some of our males are banded, but the others we can tell apart by this plumage pattern on their backside, called butt prints.
[SAGE GROUSE BURBLING]
And so to see this in super slow-mo. So this is real time first. And now slowed down, and so you can really see the wings across the feathers on the chest making the swish sound.
[SLOW-MO NOISES]
So you can see that it's deeply weird--
[AUDIENCE LAUGHS]
And un-birdlike in many ways, and awesome. But also at least vaguely obscene, if not just flat out obscene.
[AUDIENCE LAUGHS]
And they do this over and over again all morning long. And that's what female sage grouse are into.
So what do we know about sexual selection and sage grouse? People have been studying the species since the 1970s. So what have we learned? And first before I talk about that, I just want to emphasize the amazing use of these lek breeding systems, and why it's important that they breed on a lek.
So because males don't provide parental care, many of the females may end up mating with that same top male. So this male right here was one of the all time-- I think he was the all time champion in terms of the males that we've monitored in our study. And so he mated over 130 times during the breeding season, which is-- it goes on over about two months, but most of it happens within just a week. And so 37 of those moving events were on this morning while I was standing out there taking this picture, the peak of breeding. And they're only out for a few hours in the morning, and 23 of those matings happened during a single 23 minute long period of time during which he mated once a minute for 23 minutes. It was very impressive.
So it's an amazing system. If they are the sexy sage grouse on the lek, their breeding success can be enormous and so selection is very strong, favoring whatever it takes to be that guy.
And so what do we know about what females are looking for? We know that females are extremely picky. They almost all want to mate with that same top male, but not about looks. So the visuals don't seem to be the most important thing. So preferred males show up and work hard. That's the most important thing that they do. They attend the lek more often, and when they're there, they work hard. They strut, and strut, and strut.
They also have fewer scars from parasites on their vocal sacks. So they don't look scabby. And there are lots of other hens around. So hens pay attention to what other hens are doing, and so if one male already has a giant group of hens, any other hens that arrive may just go right down to that male. And so there is evidence of female mate choice copying in this species.
And also sound good. So there's a particular feature of the vocalization that females seem to prefer, and that is the longer-- a longer IPI. So what is the IPI? The IPI-- so this is a spectragram, a visualization of the sound that the males produce, with pitch or frequency on the y-axis and time on the x-axis.
And so they start out with these low frequency coo notes and a broadband pop, and then a whistle, and then a pop. And the IPI is the inter-pop interval. The time delay between those two pops when the whistle happens. And for whatever reason, females prefer a longer inter-pop interval. And we think it may have to do with-- this is Jack Bradbury and others think that it may have to do with the amplitude of the whistle note and not really the length, necessarily. But we're not quite sure of that yet.
And so sage grouse strut often considered a classic example of a fixed action pattern, which refers to this innate behavior that once you press play, they just execute the behavior in a fairly-- pretty much identically every time. There may be some variation, but pretty much identically every time.
But males may still vary many aspects of display quantity and quality. And so we've been looking at the variability in this display, and it does not seem to be that fixed. So that might not have been the best description of this behavior.
OK. So first I'll talk about two of our experiments examining courtship tactics. So first tactics to produce attractive display when there may be trade-offs, and then tactics to respond to female signals.
And so first of all, just to acknowledge that all of this work was done in collaboration with my former postdoc, Alan Krakauer, who was with me for the first 13 years of this project getting it started. So he played an important role in all of this work. And so previous research by Robert Gibson, and Jack Bradbury, and others found that females prefer high quality and quantity of these strut displays. So the strut is that behavior that you just saw the males do.
But interestingly, they found that they tend to be negatively correlated with each other among males. So each of these dots represents an individual male, and his strut rate, and his IPI. And you can see that some males have a high strut rate, some have a high IPI, but there's no one out here with a very high value for both. These dark spots are males who manage to mate. So it suggests that there might be some trade-off between these two components.
And they also found that the IPI seems to be important for long distance attraction. So for convincing the female to come visit the male up close, possibly because it's related to amplitude or loudness of display. What strut rate is more important for close courtship. That's when females are really assessing the strut rate is when they're up close with the male. And they found strut rate increases as females approach. So males strut faster and faster as the females get closer to them.
So all of those facts together caused Alan and I to ask-- is there also a trade off within individual males? So as a male increases his strut rate as they get closer to the female, does his IPI become less attractive? So is there a trade-off between quantity and quality of display? Quantity-quality tradeoffs are very, very common in nature.
And so if so, do males differ in how they express and respond to this trade-off? Do successful and unsuccessful males differ in whether they experience this trade-off and how they respond to it?
And so we examined whether some males face a steeper trade-off between quantity and quality and whether successful males use courtship tactics to manage that trade-off. So if there is a trade-off, do they differ in how they manage it? And we particularly predicted in this species, given what we know, that successful males would increase their strut rate only when females are close because that's when females are assessing strut rate. So that's when it matters the most for influencing female choice.
And so to address this question, we need to study how males adjust their strut quantity and quality with female proximity. So we would like to be able to test males with consistent proximity to a different female, and as the male increases his strut rate as the female gets closer, we would measure how his quality changed. But it's very hard to train hens to do that for you, and bird behaviors are very different when they're approaching different males on the lek.
And so this is where the robot came in. Whoops. Whoops, I'm flipping all around here. So this is the first generation. This was the very first iteration of the sage grouse robot. It was designed by an engineer at the Cornell Lab of Ornithology, Tom Fowler, and in consultation with Mark [INAUDIBLE] and Jack Bradbury, who had all sorts of sage grouse knowledge that could help as I was getting started in this.
So this is the very first draft of the sage grouse robot. Oops. And then I dressed that robot up like a female sage grouse using skins that I got from the Wyoming game and fish freezer, where people turn in specimens that they find. So I dressed it up to look like a female. And this is the finished product. So this is the first generation robotic female sage grouse, and she moves on G-scale model train tracks that we would set up the day before.
And it creates a controlled female stimulus. So we can send the females out there, have her act exactly the same for every male, approach the male in a consistent way. It also allows us to measure male display from the female's perspective. So she has a little video camera embedded in the front and a microphone on top. So we can hear what she hears and see what she sees.
So did they fall for this? Do they buy it given that there's a train track and they have no legs, and a microphone, and a video camera? The answer is yes. So these guys are very keyed up to mate, and when there are no real or robotic females around, they're often trying to mate with dried cow pies. Only a few males actually court the cow pies. Most of them just try to mate with them. So it had to be better than a cow pie but not as good as a real female. So the bar is fairly low for us in this.
And so this was some of the video from the onboard robot camera.
[SAGE GROUSE BURBLING]
[AUDIENCE LAUGHING]
That was an unsuccessful experiment. It was totally worth it for the video, and we watched that same male and real females would walk through his territory and he would go rushing right up to them strutting all along, and they would just get away. They never let him get very close. So we got better at avoiding that situation.
So we used video cameras monitoring the leks to record male mating success-- this is the number of meetings that they have with real females-- and their strut rate. So they're displayed on the lek, and we used a digital array recording for the sound. So this was our recording rig which we developed-- or I developed here at the Lab of Ornithology, and then expanded with Allen's help to have 24 microphones that we put two kilometers of buried cable across these leks to get high quality audio for all the males in order to measure IPI of all the males on the lek simultaneously.
So what did we find? We found-- in this plot here, each of these lines represents an individual male from the study and his relationship between quantity. So as he increases quantity, how does his quality change? So you can males are all over the place. Some have positive, some have negative slopes. And so we looked at how the slope of that relationship related to male mating success, and the more successful males had more positive slopes. Suggesting that successful males don't face a quantity-quality trade-off. So they can increase the rate of display without showing a decline in quality.
And so how do they do this? How do successful males pull this off? One possibility is they may be in better condition, so they just have more resources to work with. And we're still working on trying to figure that one out. But we don't have condition data for this study.
But another possibility that's not mutually exclusive is that they have better courtship tactics. So they may be using their energy more wisely to put on a good show when it matters the most. And so the evidence to support the idea of courtship tactics comes from other analyses of these experiments.
So when we look at the relationship between strut rate and male mating success, when there's a robot on the lek, we see that the most successful males are strutting at the highest rate. But when we look at the relationship between strut rate and mating success without robotic or real females-- so it's just males out there-- then we see that the direction of that relationship reverses. It's not significant in this study, but I'll show you data from a later study where it is significant and we see the same reversal in prairie chickens and sharp tailed grouse.
And so successful males strut the fastest in the presence of the robot or real females, but not in the absence of the robot or real females. So successful males crank it way up when there is a female there, and tone it down when there's no female there. And unsuccessful males just kind of blast away at a mediocre level all the time.
And so then what happens when there is a female there? How do they adjust with proximity? So here, again, every line represents a male and the relationship between quantity and how close they are to the robot. And you can see that most males are strutting faster when the robot is close. But again, there's variation among males.
And so successful males we found have a more negative slope here, suggesting that successful males are adjusting their strut rate more strongly in response to proximity, and they're starting at the highest rate when the females are close. And that's when it's most likely to influence female choice based on those previous studies. So they're holding onto their energy and using it when it matters the most, for up close courtship.
So successful males increase their display quantity without a decline in quality, and males appear to do this by tactically adjusting their displays, strutting at a high rate when females are close, which is when they're assessing male display traits. So they save their energy for when it matters the most. So if you wanted to get dating advice from a sage grouse, it would be-- whoops-- don't dance like no one is watching.
So females vary more than just in proximity, right? They also vary in other characteristics. So this is research done by my graduate student, Dr. Anna Perry, and so she's been looking at how males might respond to other aspects of female behaviors. And so we often see that when females are moving around the lek they're pecking at the ground foraging. They look like they're not there assessing males. They, in fact, are there assessing males, but they're foraging as they're moving around the lek. And when they get more interested in mating, they spend more time upright and in the general-- looking in the general direction of males.
And so Anna studied these behaviors in detail and found that real males-- real females who are upright and watching the male are five times more likely to mate that day than females who are foraging. So there's information in this behavior about the likelihood that that female is going to mate, which affects the value of that female to the male in terms just of his fitness.
And so do males respond to this? And so for this we need a fembot upgrade. So the next generation fembot allows us to examine the allocation of effort according to female signals of interest or lack of interest in mating. And so this was the engineer's first pass at the robot, and we put it inside a body mold of a taxidermied sage grouse. So it looked like an escaped rotisserie chicken at the very beginning.
And again, I dressed it up to look like a real female using skins from Wyoming Game and Fish freezers. And this is the finished version, Snooki. And so Snooki can do some behavior. So she can do the uninterested behavior where she pecks at the ground and forges. And so we can have her looking upright and looking, you know, pecking at the ground. And we have her move around every once in a while. Or she can look more interested, where she's spending more time upright and we have her move around periodically, and we can drive her where we want to go. We don't have to setup train tracks.
So do males respond to differences in female behaviors that indicate interest or lack of interest in mating? So that was the first question we set out to answer. And the second question is if they do, then who adjusts more? Is it the successful males that are adjusting their display more or is it the unsuccessful males? And so we set out to test two alternative hypotheses for how we thought this may play out.
And first we tested the differential social skills hypothesis. So this is that successful males will be better at responding to female behaviors, allocating more effort towards interested partners, which are of higher reproductive value to that male in terms of his fitness. So in other words, the things that differentiate successful and unsuccessful males is a difference in their ability to respond to these female signals.
And an example of this comes from wolf spiders, where Laura Sullivan-Beckers and Eileen Hebets found that successful males were better able to respond to female signals during courtship. And so this predicts that successful males will be more responsive to female behaviors than unsuccessful males.
And alternatively, it could be driven by constraints. So the thing that could differentiate successful and unsuccesful may be their energetic constraints. So this would be that successful males have less need to conserve effort because they have more energy and a better chance of making an uninterested female become interested. And so because the female is now up close, we're talking about up-close courtship, these males may just go for it because the female has already shown some interest because she's there and up close. And so these males, it may behoove them to just try their best and try to convince the female to mate. So they may be the ones courting both at high effort.
And an example of this comes from hanging flies. And here we see that unsuccessful males are the ones that are adjusting their courtship nuptial gifts more strongly in response to female reproductive value. So this predicts that unsuccessful males will be more responsive to female behaviors during courtship.
And so to test this, we sent the robot out on to three different leks and tested 52 males. And we had a female acting interested or uninterested. We also looked at their behavior with real females and with no females. So we tested them under lots of different conditions.
And this is what we found. So in this plot, you could see the males that mated less are in white and more matings is red. Just so that you can get used to seeing the difference between successful and unsuccessful. And so this is the number of matings by that male, and this is their courtship effort. And this is a measure of courtship effort that Anna developed, and I mean, you can see that the more successful males are courting at a higher effort. So these guys with bright red up here are the ones that are the most successful and are putting in the most effort into courtship.
And so, again, despite that female preference for high effort displays, which has been shown over and over again in lots of different studies, males aren't always displaying at their highest effort. They do seem to be making adjustments.
And so here, we just looked again at the males' courtship effort in the presence or absence of robots. So here's his effort when there are no females around, real or robotic, and here's his effort with a robot. And here you can see a strong negative relationship between these two things. And the successful males in red are down here displaying at high effort with the robot and at low effort without the robot. And, again, unsuccessful males are in the middle blasting away without regard to that social context.
So that's the same courtship tactic that we saw from experiment one, adjusting with presence or absence of females.
And so then how do they respond to differences in female behavior? So here we're using the uninterested treatment as the baseline and looking at how it differed between the interested treatment. And on average, if you look among males, they increase their effort during interactions with interested females. So most of them are adjusting and displaying more toward interested females. But there's a lot of variation in there.
And so we looked at how that variation relates to mating success. And so here you can see their effort toward interested and effort towards uninterested. And what you can see is that these successful males are more consistent. They're more close to the one-to-one with equal effort towards uninterested and interested females, where it's the unsuccessful males that are biasing more toward interested females. So unsuccessful males bias their effort more than successful males, and successful males are more consistent between these contexts.
And this is consistent with the differential constraints hypothesis. That successful males, now that the female is up close and showing some signals that she's interested because she's there, they just go for it. And if she's not looking interested at the time, they can potentially convince her to become interested. Whereas unsuccessful males are saving their energy for females that are more likely to mate with them.
And so looking back at these questions, do males respond to differences in female behaviors that indicate interest or lack of interest. Yes, they do. And who adjusts more, successful or unsuccessful males? We found evidence of the differential constraints hypothesis. That unsuccessful males, in this case, are more responsive to female behaviors.
And so far we've only addressed courtship negotiations between males and single females. So just looking at that dyad between the male and the female. But on the lek marketplace, there are often outside options. So a male may be courting one female, but then another female shows up. And so how does that affect his choice? Is he making choices about who to invest his courtship effort in?
And so this is work being done by my graduate student Ryan Logsdon, and so now we have two robots who can both perform these different behaviors. And so we've been testing an economic theory called the outside options principle or OOPs, which states that abandoning a negotiation is only favored if the outside option is more variable than the inside.
So we have a male begin to court an uninterested female for a few minutes. So he's invested in this negotiation. And then we send it outside option out there, who's either interested or uninterested. And we predict that if they follow the outside option principle, they should only abandon that first negotiation if the outside option is showing more value. So is showing interested behaviors.
And so we are just now analyzing these data. So I don't have the answer yet for that, but the analysis is underway.
And so conclusion so far looking at these various aspects of courtship tactics relative to fitness, we gain a more complete picture of how sexual selection acts on displays. It's not just about the most elaborate display traits, it's also about how males use these displays in courtship.
And so these results also suggest that the acquisition and allocation of energy is an important determinant of courtship success in sage grouse. So how much energy they have and how they spend it is important in determining who's successful.
And so I'll briefly, then, tell you about some of how this basic research informs our conservation-focused work, the role of off-lek foraging in determining on-lek success. So in gathering energy off-lek, from the food, which is sagebrush, if you're a sage grouse, and then how that influences their on-lek behavior. And then the impacts of noise pollution on lekking behaviors.
And so in our experiment with the robot, we found that males show a dramatic seasonal decline in display effort. So this is courtship effort and the number of days after peak breeding, and it drops off by about 6% per day. So they're dramatically burning themselves out as the season progresses.
And so we're investigating how these declines in courtship effort as well as courtship tactics, body condition, and mating success varies with off-lek behavior. So where they're foraging, how far they're traveling, and the quality of food that they're eating.
And so this is following up on work by Sandy Vehrencamp here at Cornell, and Jack Bradbury, Robert Gibson, who in 1989 found that display is energetically costly. And so they went out and measured the energetic cost of strutting in sage grouse, and this is, to date, still one of the only studies that's measured the cost of a sexual display in a breeding animal in the wild. It's still one, if not the only, good study of this because it's very hard to do.
And so they found some interesting results. They also found, when they captured males multiple times in the season, that the trajectory of male condition differed with success. So here, if we look at male body condition, the amount of body fat that he has available, and the date in the season, she found that the unsuccessful males started the breeding season pretty fat and lost weight during the breeding season. Non-territorial males, these are males that don't have a territory on the lek, start fairly lean and end up skinny. And successful males start lean and athletic and maintain it.
Which kind of makes sense, if you think about it. At the beginning of the NBA season, they don't start out fact and then get skinny. Right? They start out athletic and then stay that way. But it means that if you look at the relationship between condition and mating success, early season and late season, you would expect the reverse relationship. So it seems that the trajectory of condition is what really relates to success.
And she also found hints that successful males are foraging farther away from the lek, presumably eating better food. So that may be what allows them to maintain that body weight.
And so combined with the results that we found so far, we've been looking at how resources affect allocation decisions in the kinds of courtship interactions that I've already been talking about, as well as how habitat quality and diet quality relate to components of fitness. So to their reproductive behaviors on the lek.
And so this is work that I'm doing with a collaborator, Jennifer Forbey at Boise State University, and my graduate student Eric [INAUDIBLE] is heading up this project right now. And we did this with John Burt, who developed a radio tracking system called Encounternet, and I met John here at the lab of Ornithology.
And so we used Encounternet to radio track the birds. The tags have GPS and an accelerometer, similar to your phone, that can detect motion. They store the data on the tag until we can grab that data off with base stations that we place on leks. So we collect hourly GPS and accelerometer samples. So we get a point of where they were, and then we have a sample of what they were doing. So we can figure out what they were doing into these different categories based on that accelerometer data.
And so we can then map out their foraging and roosting locations, and where they're spending their time off lek and on lek. And so once we know where they ate, we can go to those different locations. And you can see-- you walk out there with your GPS, get to the location, look down, and sure enough, there's grouse poop. And if you get down on your hands and knees and look at the sagebrush, you can see characteristic bite marks of sage grouse on sagebrush. So you can see which plants they eat and which plants they don't eat. And you'll often find that one sagebrush bush just got hammered by sage grouse, and the next one was sampled and then rejected.
So a lot of variation out there. Sagebrush is filled with volatile chemicals. That's why it's so stinky. So there's lots of chemicals involved that are toxins trying to prevent herbivores from eating it. And so these samples are being analyzed now for toxins and nutritional content in the Forbey lab so we can see how well these males are gathering protein and energy and minimizing toxin intake in their diet.
So this allows us to learn how foraging success relates to condition trajectory and display effort and mating success. So important components of fitness. It also allows us to learn about characteristics of preferred plants and habitats. So it allows us to characterize good sage grouse habitat at the chemical level. So not just how high are the shrubs and what's the forb cover. But what is the quality of those plants at different locations?
So, again, the analysis is underway, so stay tuned.
And so we also have been looking at how the structure of sagebrush on leks affects micro habitat use and courtship behaviors. And so some of our leks are wide open like this. This one happened to flood. It's not always a lake. But it's a big, grassy, wide-open field. Whereas this one is extremely sage-y and the birds are all in the sagebrush talking to each other amongst the plants.
And so to respond effectively to female presence, proximity, and behavior, and to respond according to what other rival males are doing, males need information. And they also need to watch out for predators out there. So they need information, and so we wanted to know how that vegetation cover affected the flow of information and male behaviors on the leks.
And so we've done some experiments investigating this and manipulating the flow of information. And in 2017, we created high resolution 3D terrestrial laser scanning maps of leks. And I find this really exciting. So I just had to show you some of these pictures.
So you can make a 3D scan of an enormous area. We moved this around to multiple locations. You make a 3D scan that's accurate down to the sagebrush bush, and then you can place your bird in that scan and find out who he can see, who can see him, and you can measure his cover, his line of sight to different locations. And so you can map the information flow from different locations and really look at the social network, and how change and strut activity changes depending on where they are on the lek and the kind of cover that's available.
And so you can get this incredible resolution, this is a single sagebrush bush, if you want to scan it at that level. So it's a pretty cool technology.
And so to figure out where to put the birds into that map, we had overhead cameras looking down on the males. So we could see where they were, and we sent the robots out in a controlled path and saw how males moved around relative to the robots.
And so these results, they allow us to see how males adjust their behavior with the flow of information. But they also inform efforts to restore lek habitats. So they are trying, in many locations, to create locations where birds will start lekking. But we don't really know what makes a good lekking habitat. There's a huge amount of variability out there. And so this allows us to begin to understand how that variability affects the behaviors on the lek.
And again, analysis is underway.
So this is just a quick image from the overhead camera. So this is one of the sage-y leks. These are all sagebrush bushes, and these are the males. This is one of the open leks. So these are all tufts of grass. There's also some cow pies. Which you can see actually do look a lot like a female from above. And those are the males.
And so just briefly, another study that we've been working on in addition to looking at that habitat and diet quality, is we've been looking at the impacts of noise on sage grouse breeding activity. And so this is from the other side of the Wind River Range on the Pinedale Anna Cline, one of the biggest natural gas fields in the lower 48. And it used to be the prime sage grouse habitat, some of the highest density habitat in the US, and it is not anymore.
And so this is work done by my graduate student, Jessica Blickley. And so she did an experiment where we played back the sounds of the natural gas field to otherwise undisturbed leks. And so our goal is to try to find out whether noise alone impacts sage grouse lek attendance, behaviors, and stress. So that we know whether it's worth trying to mitigate for noise. So what can we do to try to mitigate the impact of these developments? Is it worth trying to mitigate noise, or is that not the crux of the problem?
And so we compared attendance on leks with experimental noise playback compared to control leks, and we looked at the change in attendance. When we played drilling noise and road noise, two of the most common noise sources, and you can see that this had a big impact on lek attendance. So road noise we found had a higher impact. So there's a 73% difference in attendance between road noise versus the paired controls, and drilling noise had about a 29% difference in attendance. So this was after three breeding seasons of playback. But this effect was almost immediate.
And so these results suggest that males are avoiding noisy areas. And we indeed see very strong, rapid declines in sage grouse lek attendance in these natural gas fields. We also found evidence of increased stress response. So a stress associated hormone was increased in fecal samples, and we found evidence of altered behavior. So they were changing their strut behaviors to avoid strutting over the noise.
And so this leads to the question of how loud is too loud? And we have been trying to tackle this problem for a long time, and I just wanted to tell you about some of our recent results here. So we looked at leks on the Pinedale Anna Cline, and we looked at attendance trends, and we had data about noise levels on those leks. And we found that lek attendance trends become more negative as noise levels increase.
So this is the lek attendance trend. Zero means they're holding steady, and this is the median noise level. And you can see they hold steady until about right here, and then things get really bad. And so we found a significant threshold at about 25 decibels using piecewise regression. So right about there, and that is extremely quiet. So above this threshold, once you cross 25, just getting up to about 27, then the probability of abandonment goes way up, as well. So all of these leks had been abandoned during that time period.
So male sage grouse attendance is negatively affected by noise, suggesting that sage grouse avoid noisy areas. And birds who remain in noisy areas are also impacted in terms of stress and behavioral changes. And the threshold of impact is very, very low. So these are, unfortunately, very picky birds and they really don't like us around very much. They don't want to hear us. So it's, of course, going to be harder and harder to find places quiet enough for species like this.
But this research was informed at every step by the basic science addressing bio acoustics and lekking behaviors. The design of the experiments, the questions that we asked in the first place, were all related to that basic science research.
So sage grouse have been an important model system in evolutionary and behavioral biology for decades. We have been studying these birds for a long time. So the cover of Nature magazine from 1932. Looks just like that dude. So we've been studying these birds for a long time as behavioral ecologists, and of course, humans have been studying them for much, much longer than that. So this is the chicken dance of the Shoshone tribe in the area where we work that uses sage grouse tail feathers on the tail bustle.
And so we have learned a lot from these birds, and when we think about extinction, we often focus on the important role in the ecosystem and our enjoyment of getting to see these birds. But of course, we have to remember the ability to learn from them. We've been learning from them for decades and our ability to continue doing that depends on them being there.
And so the more we know about their habitat, and how they use their habitat, and how they reproduce, the more it helps us when that habitat changes. So this male right here is the last male on this lek on the Pinedale Anna Cline now surrounded by natural gas drilling rigs. And this area looks like this from Google Earth looking down. So each of these is one of these large rigs. So this is a very high density developed area.
And it's not just natural gas and fossil fuels. It's also solar and wind, changes through invasive grasses that change the fire regime. These birds have a lot that are-- a lot of things working against them right now. And so as the need for conservation action becomes more acute, there's more need than ever for communication and collaboration between research focused on basic and applied questions. So we, as behavioral ecologists, have a lot to offer in protecting these species that mean so much to us.
And with that, I will thank the many people who helped make this possible, including many here at the Lab of O and at Cornell, and I'm happy to take any questions. And I'm sorry to end on such a depressing note. Sorry about that.
[APPLAUSE]
What's difference between strutting and displaying?
Strutting and displaying-- sorry, I use those terms interchangeably. So the strut is the name for the display that the sage grouse produce. So display is just a general term for a sexual display that we talk about in sexual selection. It can be a color, or a smell, or a sound. And in this particular case, the strut is that display. So those were-- sorry, interchangeable.
Have you mentioned that the high quality don't really have this trade off between quality and quantity? And so they are kind of playing [INAUDIBLE] that level regardless of whether the female [INAUDIBLE] it or not? I'm just wondering is there any evidence that females will watch the [INAUDIBLE] sort of fully displaying at a high level [INAUDIBLE]?
Yeah. That's a great question. So, I mean I do think all of it [INAUDIBLE].
Those Adjustments more. And so, yeah. The question is, do females watch him over multiple days to see if he is making adjustments? And unfortunately, we don't know the answer to that. So we do know that females will visit the lek on multiple days from work by Robert Gibson and Jack Bradbury. We do not have a well-banded population to study that. So we haven't been able to relate it to the behavior of individual females over multiple days. These guys are hard to catch.
Animals use a dizzying array of sounds, smells, colors, dances, electrical fields and seismic vibrations to convince each other to mate. These elaborate courtship signals were a mystery until Darwin’s time—after proposing his theory of natural selection, Darwin was left with the question of how the flamboyant peacock could be shaped by the same process that makes the peahen so perfectly camouflaged. There is now strong support for Darwin’s answer to this question, the process he termed sexual selection, proposing that the courting sex must be elaborate because the courted sex demands it. But how can we study the conversations males and females in non-human animals have about mating? One way to do this is to participate, controlling one side of the conversation with a robot.
Gail Patricelli will talk about using robotic females and other technology to study courtship behaviors in the greater sage-grouse, and how such research informs conservation of this iconic North American bird and its habitat. Patricelli is a professor and Chancellor's Fellow in the Department of Evolution and Ecology at the University of California, Davis.
This is the second talk in the Paul C. Mundinger Distinguished Lectureship series, established in honor of the late Paul Mundinger, who received his Ph.D. in Evolutionary Biology from Cornell.
