New paper out: Remodeling Male Coercion

New paper published in Evolution! Our study uses quantitative theoretical modeling to explore a new evolutionary possibility for systems involving sexual conflict over mate choice. Rather than evolving resistance traits that directly interfere with male coercive strategies, potentially leading to a co-evolutionary arms race, we show that females may evolve additional mate preferences that “remodel” male coercive capacity in order to expand and promote their own freedom of mate choice, or sexual autonomy.

A ket aspect of this work is that it demonstrates the importance of allowing female reproductive traits and behaviors greater complexity and biological realism when we build theoretical models to guide our intuition about the evolution and diversity of mating interactions.

Read on for more:

Sexual conflict is often characterized by the evolution of female resistance that directly interfaces with the male coercive strategy. A now-famous example is duck genital biology, wherein the vaginal tract of female ducks (shown on the left) is a convoluted anti-corkscrew, co-evolved with the male morphology (here on the right), seemingly allowing females to block unwanted fertilizations and retain the benefits of mating with their social partners in the face of violent coercive attempts by other males.

As you can see, these dynamics can potentially lead to a costly co-evolutionary arms-race, where the evolution of female resistance selects for more effective coercion, and so on.

In our paper, we explore a novel alternative to this arms race scenario, which we are calling “remodeling.”

Suppose females, faced with male coercion, could evolve an additional preference for a new male trait that enhances female freedom of mate choice?

Let me show you a heuristic example from nature where we think this might be going on:

This is the courtship display arena of the Tooth-billed Bowerbird (Scenopoeetes dentirostris) from Australia. A female that arrives at one of these leaf piles has never been observed longer than 3.8 seconds before being accosted by the male. Not so easy to evaluate a mating display in that time.

This, on the other hand, is a Satin Bowerbird (Ptilonorhynchus violaceus) courtship arena. It’s not a nest, but a structure built by the male called a bower. When the female comes to visit, she sits right in the middle.

The male displays out front and she will often spend several minutes evaluating his display. If the male wants to attempt mating, he has to go around to the back of the bower, giving the female an opportunity to escape out the front. Fascinatingly, it appears that the bower structure functions specifically to protect females from coercive mating.

We suggest that, instead of evolving direct resistance to unwanted male advances and touching off an arms race, females can actively remodel males, that is, change the males themselves, by evolving mate preferences for male traits such as the protective bowers that enhance freedom of mate choice – even though the bower is likely costly to males and hinders their coercive mating opportunities.

To explore this, we built a theoretical, proof-of-concept model where females can evolve to first choose what kind of bower to visit in order to then evaluate a male’s display

We show that, under certain sets of conditions, when male bowers are protective to females, bowers, and the female preferences for them, can invade and persist in the population in spite of the costs due to their utility in enhancing females’ sexual autonomy. Indeed, you can see in that in this model simulation, the attractive male display trait in the population, shown as the warmness of the color, concurrently increases because females are getting what they want more often.

Obviously, a striking aspect of this is the oscillations.

As bowers come into the population, fewer matings are coerced, and females with a preference for bowers get an advantage by mating more often with attractive males, as shown by the orange line. However, the protective bowers are out there in the population now, and can act as a “public good.” Females without a preference for protective bowers (the blue line) can freeload, reaping the benefits of increased freedom of choice without paying any of the costs of specifically seeking out bowers, and so they become favored briefly until bowers decrease again. Eventually it converges on an equilibrium where overall males rarely coerce and females have substantially increased ability to choose mates.  

Although the bowerbirds are a useful example, the “remodeling” process could gain purchase in any scenario where preferences can act on multiple scales allowing females to avoid direct coercion. For example, in the paper, we speculate that such a process could represent an alternative (or complementary) underlying mechanism for hominid “self-domestication,” wherein females forming friendship coalitions or choosing to associate with males with outward traits uncorrelated with aggression could have led to modern levels of reduced coercion and infanticide, and reduced sexual dimorphism in traits such as body size and canine teeth.

Photo Credits: 

  • Duck genitals: Dr. Patricia Brennan
  • Tooth-billed Bowerbird court: Macaulay Library ML278241221
  • Satin Bowerbird Bower: Dr. Hazel Parry
  • Satin Bowerbird Courtship video: Carlo Ferraro (
  • Chimpanzee: Ronan Donovan

New Preprint Up: Relational Event Models in Grouse

We have just posted a preprint for our new paper, Fighting isn’t sexy in lekking Greater Sage-grouse (Centrocercus urophasianus)! The hope is for any interested person who may have seen me present this project to be able to access a citable source to a get a better idea of the methods we used during the time before it comes out in a journal. Check it out on bioRxiv at this link here, and feel free to reach out with questions!

Here is a summary of the study and the main results (again, still pending peer-review and publication) I presented at the Symposium on Multimodality and Choreography in Elaborate Displays at the International Ornithological Congress, August 2022:

Tiputini Part I


Hey everyone! So, as you may have noticed, I entered the forest in Ecuador and promptly lost internet! Just one of the many difficulties of trying to do fieldwork and blog about it at the same time. I know it’s been a long time, but in the spirit of “evolutionary biology in real time” I would like to share with you a couple of companion posts that I wrote on April 15th. I think it will be better to show what was going on in my head at that time a couple of weeks into my stay at the Tiputini Biodivesity Station rather than try to sum it all up in hindsight.

Without further ado:

April 15th, 2015. Ecuador.

Hi all, sorry it’s been a while since I’ve had the energy to write anything. I have to admit, I’m getting pretty worn down- this stuff is hard not only physically but emotionally as well. Things have been up and down, but I’ve been trying to keep everything in perspective, and writing these posts is definitely something that helps me do that.

I’ll get to all of that in a companion post coming soon- the first thing you definitely should know is that Ecuador is beautiful, and the place I find myself currently, the Tiputini Biodiversity Station, is an incredible and very special place.

Getting here was a little exciting, but turned out fine. This place is really out there- it’s in a remote patch of forest far in the east of Ecuador in the Orellana province, part of the watershed of the Amazon River. To get here I first took a plane from Quito to a town called Coca, and then a boat for a few hours to an oil company outpost. The clearing, the concrete and the fencing provide a sharp contrast to the surrounding forest, reminiscent of Jurassic Park. From there (after having our passports checked and going through a metal detector… creepy), we went overland in a truck/bus thing for a couple hours cutting off a big bend in the river, and then into another boat up the smaller Tiputini River for another few hours, arriving at the station around 6pm, having started out at my hostel at 5:30 that morning. All these logistical details (including what time I should be at the airport) were actually completely unknown to me up until the day before my putative departure, when I finally got ahold of the administrative person in charge of these things on her cell phone. I hate being a classically over-excited type-A gringo, but at less than 24 hours to go, I was starting to get a little nervous. As I said, everything turned out fine- I ended up being able to go to the airport and meet up with the station director and a group of students he happened to be leading to the station for a field trip, so I didn’t even have to worry about navigating all these various steps on my own.

The design of the station itself is really cool. It’s barely carved out of the forest such that the foliage closes in on all sides, and there is very little open space. It’s just a few structures and cabins connected by trails and wooden boardwalks, giving it the sort of magical feel of the Lost Boys’ tree-house home in the movie “Hook,” the one with Robin Williams as Peter Pan.

The forest here is absolutely unbelievable. Take the La Selva reserve and crank the dial up to 11. The reserve area here is officially known to be the most biodiverse patch of anything on the entire planet.

By the numbers, this small region, including the Tiputini Biodiversity Station (TBS) and the associated Yasuni Biosphere Reserve contains:

~600 tree species per hectare, or every 100 square meters. For reference, the entire US and Canada combined contains ~560 species of trees.

>2000 tree species in the region

>1500 species of herbaceous plants per hectare

~100,000 species of insects per hectare (also about the same as can be found in all of North America)

~1,000,000 species of insects in the region

~370 species of fish

~150 species of frogs

~120 species of reptiles

~600 species of birds (of which I have so far seen only a paltry number)

~200 species of mammal (half of which are bats)

80% of these species don’t have scientific names yet!

The numbers don’t lie, you can feel the intensity and exuberance of the life all around you. It’s a biologist’s paradise- I have already seen eight of then TEN possible species of primates that live here: White-bellied Spider Monkeys (Ateles belzebuth), Red Howlers (Alouatta seniculus), Common Squirrel Monkeys (Saimiri sciureus), Lowland Woolly Monkeys (Lagothrix poeppigii), Dusky Titi Monkeys (Callicebus discolor) – this common name to me sounds like some sort of pirate insult-, Equatorial Saki Monkeys (Pithecia aequatorialis), White-fronted Capuchins (Cebus albifrons), and Golden-mantled Tamarins (Saguinus tripartitus). If I see the last two, Owl Monkeys (Aotus vociferans) and Pygmy Marmosets (Cebuella pygmaea), I’ll let you know! Also, based on camera trap data, there are at least two-dozen jaguars roaming around, and tons of tapirs, anteaters, armadillos, and a zillion other things I have yet to encounter. Some other highlights for me so far include an anaconda (!), red deer, tayra, and grey-winged trumpeter.

On the flip side, it often feels like instead of 100,000 species of insect per hectare, it’s 100,000 species of insect per Sam. Remember bullet ants? Well forget about them (don’t worry, they’re still around), it’s time to meet Phoneutria spiders!!! Commonly known as Banana Spiders, Wandering Spiders, or, my personal favorite, Matacaballo (horse killer!!), these big-as-your-hand members of the genus Phoneutria are aggressive hunters and venomous on the level of a serious snake bite. While wimpy bullet ants just hurt a ton, they say a bite from a wandering spider could actually kill you if you fail to receive medical attention. And, as if this weren’t enough, apparently the venom is not only extremely painful but has the disagreeable side effect of causing an uncontrollable erection in the victim. (This may require some fact-checking.) However, like bullet ants, these guys are distressingly numerous. I’ve only seen two so far, and have avoided them without incident. Although I will say that the first one I saw because it suddenly pounced on a katydid sitting on a leaf not far from my face- I just about jumped right out of my skin! The video below is of a Banana Spider in the lab building. There was also one in the bathroom…


I don’t think it’s possible for tourists to really come here specifically, but if you are interested in coming to see all the amazingness for yourself, the park at Yasuni accepts visitors and nearby eco-tourism lodges at the Napo Wildlife Center or the Sacha Lodge are a fantastic way to experience the environs of the remote Napo region of Amazonia.

The incredible intact forest here and it’s wildlife have been preserved so well up to the present through no accident. We have the indigenous semi-nomadic Waorani people to thank for this, for this region around the Tiputini River has been their home for millennia, and remains so even now. The reason the forest here remained untouched for so long is due to their proud, highly territorial and sometimes violent disposition: traditionally, they will kill absolutely anyone who enters their land. They were very serious about this, and to some extent still are, and so the early European settlers of South America gave them a wide berth. There are still two small Waorani tribes that are as yet “uncontacted,” and to this day will kill any trespasser on sight. I write “uncontacted” in quotes, because it is more of a voluntary isolation: while they have never had direct dealings with outsiders, they have friends and relatives in other Waorani communities that have, so they are aware that an “outside” world exists. They’ve basically decided that based on what they’ve seen and heard they would prefer to be left alone and continue to live in their traditional ways.

The reason anyone ultimately decided to barge in here at all was oil prospecting in the ‘70’s. The national oil company managed to strike deals with the Waorani leaders, promising things like electricity and blue jeans. Largely they’ve made good on their offers, but it’s kind of a catch-22. No one realized the noise, pollution, and destruction that would come along with the rights to the extraction of oil. Equally bad or worse in the eyes of the Waorani, many of them are growing frustrated with their lack of opportunity for self-determination that comes with the oil company’s control of the region and their growing reliance on the oil company for their livelihoods as they lose their old ways and begin using fuel for boats, electricity for TV’s, and gain increasing access to such things like alcohol and cocaine.

There are some stories of Waorani villagers felling trees to block the few roadways and then demanding money or goods on pain of death from the people that come through. Sometimes it seems comical: apparently a previous station manager was told by some Waorani men to hand over five thousand dollars immediately, or they would kill him on the spot. He said he didn’t have five thousand dollars, but he did have a couple of tasty sandwiches. After considering for a moment, the men decided that was fair and let him pass. Kind of funny, but they really were serious about killing him- those were probably the most valuable sandwiches ever prepared, the most priceless mayonnaise ever spread! These things really do happen from time to time, and mostly the demands of the villagers are met. Unfortunately, these episodes seem to me representative of the precarious and ultimately unstable balance struck between the oil company, the government, and the Waorani. I worry that the more frustrated and disenfranchised the villagers become, the more little things they will do to lash out, and the more excuse the government will feel like they have to get rid of them for good. Already several Waorani men have been imprisoned for demonstrating, demanding that oil drilling cease, or for crimes such as stealing from oil company installations or sabotage. This kind of slow, insidious death of a people is heart-breaking, but as a US citizen, perhaps equally heartbreaking is the feeling that I’ve seen it all happen before.

The station prides itself on being a source of advocacy for the Waorani. Just as an example, they sponsor (through the Universidad San Fransisco de Quito, their parent institution) a full-ride scholarship for Waorani students so that they have the opportunity to deal with outsiders on an equal footing. In general, people involved with TBS try to interact positively with their neighbors. They donate filtered water and some food and fuel, and buy their food for the kitchen from the local communities. The station in fact employs several Waorani men as general staff and guides. Because of all this, I have had the opportunity to have some very friendly interactions with a few Waorani folks, and I now know how to say hi and introduce myself in “Wao,” their language. It wasn’t so long ago the only phrase in Wao anyone bothered to learn was “please don’t kill me.”

In spite of the advocacy work being done by TBS and affiliates, this place is at serious risk of seeing the loss of unique and ancient cultural and well as biological treasures. The station itself, built specifically to study and help defend biodiversity, is no exception. When the founding director chose the land for TBS in 1994, it was intentionally made to be outside of any ancestral homelands, established parks, or oil concessions. A few years ago, however, the oil company renewed its agreement with the government, and in the new deal a new concession called “oil block 14” was created that encompasses the station and the reserve area. If the oil company decided to, they could legally flatten the whole area first thing tomorrow, or sink a well right next to the lab. So far they haven’t, but already there are plans to open a new road just 5k from here.

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Remember those nice models I so lovingly and carefully crafted in the museum workshop? They totally don’t work. At all. When we tried placing them on nearby branches and playing recorded calls, (a technique that often works well with monogamous territorial birds), not only do the male Red-capped Manakins seldom respond to the sound, but when they do, they come over to search for the source and completely ignore the model. I can see them thinking to themselves, “Is he here? Maybe over here? I know, I’ll check behind this utterly unconvincing model of a bird…”

As I wrote before, I had a hunch that this was going to happen, so I sent an admittedly panicky message to our inimitable collections manager at Yale, Kristof Zyskowski, looking for options. Perhaps if models didn’t work, the birds would respond to taxidermy specimens that are sure to at least have all the right feathers and colors. Amazingly, he dug around in the collection and managed to find an old specimen of a male Red-capped Manakin that had no data associated with it. No-data specimens are nice to look at, but of very limited use for museum science, so with my advisor’s blessing (he’s the curator of ornithology) we arranged to have it transported down to Costa Rica with Frank. As one can imagine, this requires quite a bit of paperwork, and I am eternally grateful to Kristof for taking care of it, among all the other things I am eternally grateful to Kristof for. Based on the specimen’s condition and the style of its preparation, I think it may have started its life as part of a display of curiosities in some late 19th or early 20th century wealthy person’s parlor. That’s pretty neat, and would explain the lack of any data.

In another amazing stroke of luck, I also managed to get my hands on a specimen of a female red-cap! A few years ago, a researcher that has been coming to La Selva station for a long time named Kim Smiley decided to start what she dubbed an “accidental museum.” She began telling everyone to bring to her any dead animals they found so she could prepare them for the nascent collection. The lab manager at La Selva seems to have been traumatized by the stinky sloth carcasses being prepared in the lab area, but the specimens look really great, and now they are used in local education and outreach programs.

As a result of this effort to collect dead stuff, I was able to do some digging in the freezer and found a female Red-capped Manakin in excellent condition that had been unfortunately killed upon hitting a window the year before. With Kim’s permission, I was allowed to take it out to use for my project. I’ve never been so excited to find a dead bird!

Of course a stiff century-old museum study-skin and a frozen dead bird do not convincing models make. They needed to be turned into “taxidermy mounts”- made to look like living birds. While I have experience preparing bird skins for museum collections, this was my first foray into the art of creating lifelike specimens as if for display. The main differences between a study-skin that just lies on its back and a taxidermy mount are glass eyes and some sort of internal wire structure that lets you pose the bird in an appropriate way. Michael Anderson, Yale Peabody Museum Preparator, gave me some helpful tips over email, but for the most part I had to wing it (pun intended).

Here’s a little bit of the process: (warning, a couple of the pictures are a little yucky)

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I think they turned out pretty well! Not too shabby for my first try.

Unfortunately, I didn’t have any extra glass eyes, so it was with a heavy heart that I was forced to dig the eyes out of the original models.


In parallel, Frank and I began inventing new ways to get the models onto high tree branches without the aid of a ladder or some sort of stick that might disturb the birds’ behavior. This was a ton of fun, and we developed a simple contraption that I think is a pretty slick solution. It lets us get a specimen up to an arbitrarily high branch, and even gives us the ability to wiggle it around a little bit for lifelike movement effects! Here’s a demo of Prototype Mark II:

Armed with our new fancy taxidermy models and patent-pending elevation system, we were really excited to give these a whirl in the field. However, I am very sad to report that our streak of bad luck continued and the birds once again spurned our efforts. They either just don’t recognize the models as birds, or they DO recognize them as the kind of creepy zombie birds that I suppose they are, in which case I don’t blame them for not interacting with them socially. It may be that it’s like bringing a storefront mannequin to a nightclub- it shares lots of attributes with a real human, but you wouldn’t expect any guys to try to take her home. Incredibly, these sorts of models do in fact work on many species of birds, and it’s a shame they are insufficient for C. mentalis.

BUT we’re not done yet- without models to help us we’ve just got to do things the old-fashioned way, waiting for natural behavior to present itself. One thing we want to know is how much time out of the day the males spend socializing with one another as opposed to sitting alone, foraging, or displaying for females. How important is social interaction in the life of a Red-capped Manakin? This will be key for comparing with the behavior of the Golden-headed Manakins in Ecuador. We have been studying the birds’ patterns of movement and behavior, and finally we started collecting the time-budget data. We went through many iterations while working out the methods- here’s a test of the voice-recorder method on a particularly slow afternoon:

La Selva Radio 4

We eventually settled on a method were we sample a focal male bird’s behavior at two-minute intervals for one hour. Frank keeps time and I write down the data so someone always has eyes on our guy. We decided this is better than recording by voice mostly since it removes the necessity of post-processing the data and combing through all our nonsense.

In the meantime, we were invited by Paul Foster, director of the nearby Reserva Ecológica Bijagual, to come check out that site. We continue to be concerned about the seeming lack of abundance of the Red-capped Manakins at La Selva, so we were interested to see if we could increase our sample by adding another site. Additionally, Bijagual is up at slightly higher elevation (~400m as opposed to <100m at La Seva) and we were curious if that would lend itself to higher abundance of our birds and therefore more opportunities. The reserve is absolutely beautiful, and had a wonderful time trekking around nearly the entire trail network with Paul hunting for manakins. We managed to find six more potential lek sites, certainly more concentrated within the suitable old-growth habitat than at La Selva, but that habitat was pretty restricted, with much of the reserve being managed secondary growth or formerly selectively logged. All things considered, it seems like it would indeed be a reasonable option for augmenting our sample from La Selva.

I have since managed to find two additional busy leks at La Selva, but I still do not have very many, even with the birds from Bijagual. At this juncture it’s unclear how to proceed; whether to keep plugging away at what I have on the Caribbean coast of Costa Rica, or attempt explore some other localities further afield if I decide I really need to sample more birds. I keep hearing rumors of a magical land brimming with manakins down in Panama, but it’s hard to know what intel is solid. I may have to check that out eventually, but if anyone reading this has any more info, I’d be happy to hear it!

This kind of natural history research is difficult because the sample sizes are necessarily small, but that doesn’t mean the questions aren’t worth asking, or that the work isn’t worth doing. With the exception of the non-functioning models, my time in Costa Rica has largely been a success- I found the birds, demonstrated that they are possible (in fact, pretty easy) to catch, established that with practice they can be followed and observed, and ironed out some methods for observation. We also managed to get a pretty decent amount of video data that will allow us to make detailed descriptions of the male-male display interactions. If I can figure out how to convert the files appropriately, I’ll post some little examples.

Things have been pretty busy, and actually, as I write this post now, I am sitting in a hostel looking out over beautiful Quito, Ecuador. We said our goodbyes to La Selva on Monday the 23rd, having had a wonderful time and having so far managed to avoid the bullet ant’s vengeful jungle sting (but not without some close calls!). I want to thank everyone I crossed paths with there for their friendship, kindness and generosity. Hopefully I’ll be headed back there to do some more work soon!

The boat for Tiputini Biodiversity Station (my next site in the Amazon region of Ecuador) only runs on Mondays and Fridays, so I have been forced to take a break here in Quito for a couple days. The rest is welcome- I’m super exhausted from the work so far, and I have to get energized to chase the Golden-headed Manakins when the time comes!


View from the terrace at The Secret Garden Hostel in Quito


Wow, it’s been a little while! There have been lots of developments on the science side of things, but I wanted to take a step back and talk about some cool creatures that I’ve had the pleasure to encounter. The rainforest isn’t just Manakins and bullet ants, you know!

One of the coolest things I’ve come across so far was a beautiful puma (mountain lion, Puma concolor) chilling out near the trail. My friend and fellow researcher at La Selva, Diego, was the one who first spotted it and took this picture:


For me, it was definitely the ideal scenario for meeting a mountain lion- the cat was sleeping on the opposite side of a small ravine, so we could admire it without too much concern about getting pounced on.

Although, it was less ideal in other ways: it was looking pretty sleepy, probably having just stuffed itself full of peccaries, but it definitely perked up when it saw Diego’s 18-month-old son, Andrés. This puma also had chosen to nap in a spot only 175m down the trail from the station, pretty close to home!

I walk by there several times a day and I haven’t seen it since. Although it was a little disconcerting to know it was hanging out really nearby, it felt a lot better when I knew exactly where it was…

These large cats are generally very hard to see in the wild, especially in Central and Latin America where many forests are degraded by hunting (not only of the predators themselves but of potential prey species). It is a real credit to the diligence of the conservation efforts of the Organization for Tropical Studies and the Costa Rican government in nearby Braulio Carrillo National Park. The back of the La Selva reserve actually forms a continuous corridor with Braulio Carrillo which is likely responsible for the potential puma, jaguar, and tapir sightings here. The strong history of protected forest in this area is also the reason why one can easily see many other awesome animals (in particular, birds) that would otherwise be either absent or extremely wary of humans due to hunting, including Great Tinamou (Tinamus major), Little Tinamou (Crypturellus soui), Great Curassow (Crax rubra), and Crested Guan (Penelope purpurascens).

The puma was near enough, but there is a lot of stuff even closer to home. The staff at the research station does an incredible job keeping the place immaculate, but there is only so much you can do to keep the forest from creeping in.

Starting about a week ago, I began finding rather large droppings in the middle of my floor. I offhandedly mentioned to someone that I thought I had rats in my room, and she said, “oh no, that’s the geckos.”

Sure, I knew I had geckos in my room- pale-colored little guys about three inches long that make chirping sounds at night. I like them because they’re cute, and they eat all the little bugs. But there was no way they were producing the sizeable mystery-poops.

“Ha, you’ve never seen the BIG ones,” said my friend.

Sure enough, I soon found this dude stuck to the wall:

the culprit- a 12cm Turnip-tailed Gecko (Thecadactylus rapicauda)!

the culprit- a 12cm Turnip-tailed Gecko (Thecadactylus rapicauda)!

Poop mystery solved.

Another organism I find myself sharing my space with is much larger than any big gecko or puma: a colony of leaf-cutter ants! While the ants themselves are quite small, the colonies are humongous, on the order of millions of ants. I am lucky enough to have a column of them constantly streaming by my front door, and the tree near my cabin is unlucky enough to be the target of their efforts. They are perhaps the most important herbivores in the forest, harvesting huge amounts of leaf biomass to feed to fungus colonies they cultivate in their nests. In a fascinating example of natural agriculture, the ants then subsist on the fungus they grow. There are many, many colonies in the forest, making leaf-cutter ants nearly ubiquitous here. They are responsible for transferring large amounts of nutrients and resources like carbon contained in the leaves underground to be decomposed. Exactly what the effect of the tiny leaf-cutter ants is on the ecosystem is the subject of active research (specifically, my friend Diego’s research!), but it is certain to be on a grand scale.



While there are a bunch of neat animals making themselves at home in and around my home, the neotropical rainforest is full of creatures that are happy to make own their homes. One of my favorite animals I have seen so far are White Tent Bats (Ectophylla alba), a near-threatened species of bat that is one of only two species in the world known to have white fur. These tiny guys construct roosts in large heliconia leaves by biting down the edge of the central rib causing the leaf to fold down forming a “tent.” My friend Cleo found these two puff-balls huddled under a leaf on a rainy day last week:



Other curious things:

Millipede (Nyssodesmus python) sex:


Finally, check out this strange creature: if anyone has some info on this, comment on this post, I would really appreciate it!



That’s all for now- more science and my full Costa Rica birding list coming in a couple days!

Got One!

IMG_3793Actually, four (so far)! When I left you guys last time, I had finally found some decent male group display (“lek”) sites. I decided that, since confirming the birds are actually here, to switch gears and focus on figuring out how to capture them. Since I am interested in discovering how the males’ social behavior relates to their tendency to interfere with female mating decisions, I need to know who’s who on the lek. Not being a Manakin myself, I can’t reliably tell the difference between individuals, so I have to mark them in some way. For me, this meant coaxing them into finely-woven “mistnets,” carefully disentangling them, and placing little colored bands on their ankles. Red-capped Manakins display at about 5 meters or more above the ground, and the standard mistnet is about 3 meters high, so this task was another potentially significant hurdle in terms of the success of the project.

It turns out the way around this difficulty involved lots of patience and careful attention, which I am quickly learning is apparently the way with most things in this kind of work. When I first found the leks, the behavior of the birds was completely overwhelming. Based on what I had read and heard about, I was expecting males to have well-defined territories that would be easy to spot and map out. What I got was lots of confusing flitting around, with multiple males all up in each other’s business, displaying on numerous perches, then disappearing for long stretches of time. Sometimes a male would favor one area for a bit, then fly off and hang around a tree 50 meters away instead.

When I was younger, my parents got me one of those awesome photomosaic jigsaw puzzles. The final composite image was of a space-shuttle launch, made up of tiny space-related thumbnails. I was so excited to put it together, and then I opened the box and dumped out the pieces. Uh-oh. My first day on the lek felt a lot like that.

After a little freak-out and some encouragement from my extremely wise and level-headed girlfriend (check out her amazing fieldwork blog here where she most recently had audience with Prince William!), I went back to the same site every day for four days straight, and simply watched. I spent most daylight hours (minus those spent sitting and being forcefully reminded why it’s called a “rain”-forest) just following the guys around, watching where they go, where they like to sit. While they jump around a lot, Red-capped Manakins are actually a fairly conservative bunch, and definitely have favorite spots and ways of getting to them. These spots include display branches, but also little melastome berry bushes, their favorite food. Additionally, the system seems to be more fluid among the males, but becomes a bit more rigid when a female arrives on the scene. Suddenly all the males being displaying in earnest, revealing which branch is particularly theirs, and calling, attempting to convince her to come check out what he’s got going on in terms of dance moves. Lastly (and really luckily), it seems that while the males like to perch rather high up, they often swoop down low when they travel between areas.

All this intelligence-gathering led me to make relatively educated decisions about where to place my nets, and it has really paid off so far! While it sometimes takes a long time to get a net set up in the right place (I’m not allowed to cut or damage any plants inside the reserve, so I’ve been tediously peppering the forest with little bits of string, tying leaves and branches out of the way), up to now I haven’t had to wait more than about 15 minutes for my target bird to fly in.

The process of banding the birds has been a little bit stressful; while I have lots of previous experience, I’ve never felt like I knew the individuals so well before. Of course the bird is always a little unhappy about being caught and handled, even though I’m quite gentle and get it over with quickly. It’s silly, but I guess it’s a bummer that my little friends so clearly don’t like me as much as I like them!

As of now I have four birds banded and released, three adult males and one immature comprising all the residents of my current focal lek, which I have affectionately named Pink-Blue, Orange-Green, Blue-Orange, and Green-Green.IMG_3789 I can’t quite rest easy yet though, since I have yet to have a confirmed re-sighting of BO or GG. It would mean a big change in tack for the project if it turns out that capturing birds at the lek potentially causes them to abandon their territories at high rates. I can’t worry too much yet though, since the weather has been pretty bad for the last couple days and they could easily just be hunkered down. All I can do is keep going out and looking for them!

Model Organism

Now that I have a whole lek banded, our next goal is to test out some cool methods that I hope will really improve my ability to draw comparisons and get a sizable amount of data. The thing is, I want to gather reliable data on rates of disrupted courtships as well as the aggression of males towards other males and compare across species. Female visits in Manakins generally are pretty sporadic and copulations are pretty rare (as I said in an earlier installment, most males NEVER mate!). It is also difficult to account for the differences in temperament between individuals. For males, depending on the species, they rarely disturb the social order (whatever that may be or however it actually works), so it is difficult to understand what the “punishment” might be for a male who doesn’t follow the rules and respect other males’ space. Therefore, we are attempting to use model birds to try to elicit displays to fake females and aggressive reactions to fake males. This would give us the chance to control for timing and numbers of interactions and the opportunity to gather an unprecedented kind of data for this group of birds.

I use the words “our” and “we” in this case because I have just been joined yesterday by my friend and labmate Frank Stabile! He’s going to be here in Costa Rica with me helping out on the project for the next two weeks, about which I am super excited and for which I am extremely grateful.

I learned to hand-make the models we will be testing out the old-school way with significant pedagogy and guidance from Yale Peabody Museum of Natural History Preparator, artist, and amazingly cool guy Michael Anderson. I had a really fantastic time hanging out in the Peabody workshop learning these techniques, and while this would be dipping a bit into the past (as opposed to “real-time”), I thought it would be fun to use this platform to share the process and final product:

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Sadly so far the models haven’t been working super well, but we’re still figuring stuff out and trying some new things. These include super-gluing on a few actual feathers and climbing up to place the model directly on the display branch (easier said than done):

Ok, this is probably quite enough for one post. Oh, right:

Bullet Ant Update

Pura Vida


After months of messing with government permits and the Institutional Animal Care and Use Committee, delays due to blizzards, and many, many iterations of my plans for the project itself, I have finally arrived at La Selva Biological Reserve in Heredia, Costa Rica. The reserve is classic lowland tropical rainforest, the kind you learn about in elementary school, complete with toucans, monkeys, and giant Kapok trees. Most of you who will be reading this know that I have had some experience working in the tropics as a field assistant before, but this is my first time developing and heading up my own project of this scale. It’s certainly the biggest thing I’ve ever tried to tackle both logistically and intellectually. But, while it’s been a little bumpy, I’m starting to figure it out:

 Step 1: Find birds

I arrived at the station in the afternoon on Tuesday, Feb 17. I went into the office and met the assistant station director who asked me, in an unsettlingly skeptical tone:

“So, you want to work on the red-headed ones? …Have you seen them here before? Do you know where to look? Did your advisor tell you where?”

Red-capped manakins are listed as “common” in the field guide to Costa Rican Birds, and are marked “abundant” on the station’s bird list. A former member of my lab, Kim Bostwick, did a whole chapter of her dissertation here at La Selva on the displays of these birds and the snapping wing sounds they produce. I figured, they’re everywhere, and La Selva is the place to go. I’m a decent birder, how hard could it be?

“Nope!” I replied, suddenly feeling like a total idiot.

It turns out they’re pretty tough to track down, and most casual wanderers in the forest will miss them. The asst. director told me of a rumor that songbirds have been in decline at La Selva for years, red-caps included, and that he hadn’t seen one in years. I set about interviewing anyone I could about potential lek locations. Manakin leks purportedly can persist in the same area for decades, with young males coming in to replace the elder statesmen that pass on. This is a good thing, because while the other researchers here (Hi Soren, Amanda, Nicole, Carlos, Erin, Susan, Diego!) kindly promised to keep an eye out for the little red-and-black guys, none of them had ever seen one, and the most recent time any of the station’s professional naturalist guides had seen birds displaying was at least five years ago. I was able to gather some intelligence on a few spots to check, but I was pretty gloomy and a little whiny when I recorded this video after about twelve hours of searching turned up nothing:

Not my best moment.

The next day, I was up at 5am and back out on the trail. I decided to push a little farther than I had the day before, and just as I was hatching plans to pack up and move to a new site in Panama, I heard the distinctive “hip, hip, hooraaaaay!” of a Red-capped Manakin. I immediately dove into the palms and lianas, and found him sitting smugly on his branch about 20m off trail. As I’ve found out in the last week or so, the only remedy for a dearth of manakins is LOTS of wandering around and careful listening. At this point, I’ve hiked every major trail in the reserve at least once and identified two busy leks and nine other potential lek sites. Woo!

Apparently the guides don’t take visiting groups very far from the station, so they never have any reason to trek deep into primary-growth forest that the Red-capped Manakins prefer. They’re out there, they’re just sneaky.

There is still a potentially troubling issue of the level of activity and the numbers of individuals at each site, but as my colleague Teresa told me before I left, if the birds exist at all when I show up, I should consider the trip a success. So, Step 1: check.

 Step 2: Don’t die

I’m not actually too worried about this, but it’s worth noting that there have been some unforeseen sources of trepidation beyond the garden-variety tropical risk factors like venomous snakes and malaria. A few days ago, I had scoured all the trails near the station but I had only found one reasonably active lek. I had a hunch about some other areas, but they were all around the far perimeter of the reserve, so I planned an all-day loop. Around midday, I had just heard a manakin calling in the distance when there was a crash in the trees above my head. It was a troupe of adorable capuchin monkeys! I was like, “Hi guys!” and they were like, “Screw you!!!” As soon as they noticed me, they all started grunting and grimacing and shaking the leaves. When I didn’t move, they started breaking off sizable branches and hurling them down at me! So rude!

Continuing with the “slightly stressful interactions with wild animals” theme, I also had several run-ins with ill-tempered peccaries. Called “chanchos” in Spanish, we have a group of these hairy little wild pigs that hangs out in the lawn around the station. I often have a few sleeping in a pile outside my cabin. They’re usually really chill, and we mutually ignore one another. The chanchos at the far end of the reserve, however, are not so used to people. Numerous times during my hike I found myself in a faceoff with a bristling, tusk-gnashing peccary that decided it didn’t want me in his space. At first I tried to simply ignore them, but this just emboldened them. I tried running at them, and it mostly worked, but there was one guy who totally called my bluff. He charged at me and without thinking I did the exact same thing the monkeys had done to me earlier in the day- I started yelling and grabbed the nearest sapling, giving it a violent shake in his direction. Totally worked! Thanks, last common ancestor of monkeys and humans! The only bummer is that if I have to do that, it also scares off all the birds.

The other source of trepidation so far is bullet ants. These are not your momma’s ants. These ants are inch-long, solitary hunters with huge jaws and a bad attitude. They are called “bullet ants” because, as close relatives of wasps, they supposedly pack a sting as painful as a gunshot. In my previous experience, bullet ants were something to watch out for, and avoid on the rare occasions that you came across them. But now I’m slowly becoming resigned to my fate as a bullet ant victim. This whole place is el mundo de bullet ants. They’re EVERYWHERE, especially in the habitat where my birds are found. I’ve been encountering dozens per day and have stumbled across several nests already. It’s only a matter of time…

Step 3: Relax and Enjoy… I might turn out ok! …maybe!

I guess all in all I’m a little scared because I am coming to terms with how SUPER HARD this is going to be. It was tough enough just to find the birds, and this next week my goal is capture and tag some of them, which is probably going to be fun and exciting, but also much harder.

Perhaps because this project is so personal, the specter of failure is creeping around in my mind a lot more than it normally does. This is in some ways the culmination of a dream I have been hatching for a long time now. Since I started down this path to becoming an evolutionary biologist, my goal has been to be, at least in part, a field biologist. To get my hands dirty, and to take the time and have the patience to experience the wonder and beauty of the organisms whose history I am trying hard to comprehend. Maybe it’ll totally suck. Maybe the whole project will implode and I’ll have spent just over two months getting crapped on in the jungle, collecting useless data and wasting a boatload of money.

At least I’ll know that I tried, that I didn’t just give up because it got hard.

For the time being, I’m glad I’m here. Hearing the howler monkeys every morning reminds me that I’m exactly where I’ve worked so hard to be. I’ve seen so many wonderful things already in my forest wanderings, much more than I have space to write about- I’ll try to highlight more of the biodiversity awesomeness in future posts. And who knows, maybe it’ll all turn out great!

Blog should stand for BackLog.

This is the first post! Let me get you up to speed…

Most of my dissertation work so far has been building theoretical computer models that serve as proofs-of-concept for new ideas about evolution. I create imaginary populations of animals and I give them rules to live, reproduce, and pass on their genes by. This platform allows me to probe what sorts of things are possible to evolve, and under what conditions. For example, can the cost of having unattractive or low quality sons drive females to evolve new strategies (like convoluted vaginal tracts) to combat coercive mating attempts from males that they do not prefer? I’ve created a model that suggests that this is indeed the case, and I hope to have the chance to write a bit more about it and its significance soon.

I’m really excited right now because I am working to develop a project that will hopefully ground-truth some of my theoretical ideas related to sexual conflict using observations of animals in the wild.

For years, I have been fascinated by lek-breeding birds. In these systems, males display, often with colorful plumage and spectacular dances, in aggregations (leks) that females visit to choose a mate. Most females agree on which males are most attractive, so relatively few males are successful… ever. Most males will never mate, their entire lives. Males (especially the unsuccessful ones) will be under natural selection to increase their own relative success by interfering with females that visit their neighbors’ courtship displays. However, unchecked disruption would prevent female choice, and lead to a breakdown of lek-based mating. Thus, mechanisms for regulating male courtship disruption must be necessary for a functioning lek, yet the nature of these mechanisms and their evolutionary drivers remain unknown.

To pursue this mystery, I have come here to the lowland rainforest on the Caribbean slope of Costa Rica to study the social and mating habits of some little birds called Manakins. I’m here to look at a species called the Red-capped Manakin (Ceratopipra mentalis), known in the literature for their low levels of courtship disruption, and known worldwide for their suave “moonwalk” mating dance (shoutout to Dr. Kim Bostwick, former Prum Lab student). In about a month, I will be headed to the Amazonian region of Ecuador to hunt down the Red-capped’s apparently more boisterous and confrontational closest relative, the Golden-headed Manakin (Ceratopipra erythrocephala). I will be looking at the social behaviors of the males and the mating decisions of the females, drawing comparisons between the two species’ social systems to try to gain insight into the evolution of stable leks. That is, if everything goes as planned…