Science Friday - Northwest Passage Project, Birds and Color. Aug 9, 2019, Part 1

Episode Date: August 9, 2019

First, tardigrades on the moon, feral hogs on Earth, and more news from this week’s News Roundup. Scientists and students navigated the Northwest Passage waterways to study how the Arctic summers have changed. Last year, one day into expedition, the boat ran aground and cut the mission off before it could get started. This year, the team successfully launched from Thule, Greenland and completed their three-week cruise. Birds don’t just see the world from higher up than the rest of us; they also see a whole range of light that we can’t. How does that shape the colors—both spectacular and drab—of our feathered friends? Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Perhaps you've heard the news by now. There is life on the moon. Just so happens to be caused by an accident. Back in April, the Israeli aerospace company, Space I.L. Was all set to land the first private spacecraft on the moon. But minutes before touchdown, the lunar lander crashed, spilling its payload onto the moon's surface,

which included those very hardy, tiny tardigrades. Here to tell us about how we got there what the first water bears on the moon mean, and to give us the rundown of other short subjects in science, science journalist Eleanor Cummins. Welcome us to Science Friday. Thanks so much for having me. So how did we get lunar invasion of tardigrades? Right. So as you said, back in April, Space IL accidentally crashed their lander on the moon.

Their main payload was human knowledge. They were bringing things like books and Wikipedia pages, but they also had this sort of surprise payload, these tardigrades. So as you may remember, tardigrades are these really incredible micro animals. They have eight legs and segmented bodies, and they seem to survive like literally anything. We found them at very low pressure, a very high pressure, in extreme heat and extreme cold. They've even been to space before, and some of them lived. So they're pretty incredible animals, and now they seem to be on the surface of the moon.

So the $64 question, could it be that these tardigrades are still alive? or in hibernation somehow? So the tardigrades were sent up dehydrated. They have this ability to sort of shrible up and effectively turn into glass at a cellular level, and so that's how they were delivered to the moon. It is entirely possible that they are still alive. We've been able to rehydrate tardigrades

after years in a dehydrated state. So if anyone ever gets the chance to do that, they may spring back to life. Wow, they're not going to bring them back, are they? I don't think they have any plans. to go back and get them. This is kind of cool stuff. But the whole policy is, you know, in space exploration,

is trying not to litter other planets with our biome or anything that we bring up there. But that's been broken years ago, hasn't it? Yeah, this was totally legal for them to do, which may be surprising to a lot of people. NASA classifies these celestial bodies according to, like, the priority of concern for contamination. So on Mars, we think that it may have the potential

to have its own life, and it could hold other life in the future, so we have to be really careful about what we bring there. But the moon, we're pretty sure, doesn't have any of its own life and probably couldn't harbor any other life, so it's kind of a free-for-all. These tardigrades are definitely not alone.

They're up there with a lot of Apollo 11 poop, among other biological matter. Yeah, that's been talked about a lot. 50th out of anniversary. Never mind, we won't go there. Something almost as wild is that there's some news floating around the internet about feral hogs,

this week? Yeah, so this was a viral Twitter sensation. Basically, a guy responded to a sort of politically charged tweet about gun control with a question asking how he could kill quote, 30 to 50 feral hogs that were reportedly

running amok on his property and scaring his children. And it became this meme where people were quoting 30 to 50 feral hogs and putting all of these videos together, but it's actually a really serious issue. In the United States right now, there are estimated 7 million of these feral hogs in 35 states. They're concentrated in the southeast.

While they don't really like interacting with humans, they're definitely dangerous, but worst of all, they're ecologically disastrous. They will eat anything they can get to, and they like to root up plants, so they'll just totally clear out an agricultural area or wildlife. Wow, wow. Is there a problem, the danger they might spread everywhere or go all over the place? They're already pretty much everywhere. Basically, back in the 1500s, colonists started bringing over domesticated pigs, and then in the 1900s, game hunters started stalking wild boar, and those two animals combined into these wild feral pigs that we have all over the U.S. today. They've been spotted throughout the lower 48,

and they are posing a really big problem, which is why the U.S. Department of Agriculture wants to go after them. So these harks are not indigenous to the United States. No, not at all. They're brought over by European settlers, and where are they mostly now concentrated? They're in the southeast, and that's where people really like to hunt them. So in Texas, for example, people go out and hunt about 30,000 of these hogs every year, which sounds like a big number until you consider that Texas has an estimated 2 million of these animals running around. Wow. And so is there any program to try to round them up or to take care of them somehow? Yeah, so earlier this year, the U.S. Department of Agriculture decided to fund a pilot program to sort of figure out how they could contain them.

And they're trying a bunch of different strategies. One is to take helicopters out, locate a group of feral hogs, and then shoot them all down. Another is called the Judas Pig Strategy, which is where if you find a loner pig, you strap a GPS device to its body. And then when it returns to its group, the proverbial 30 to 50 feral hogs, you can track them all down and kill them. So there's a mass hunt going on. Absolutely. Wow.

Well, let's move up to something different. Scientists are taking a second look at some dinosaur bones from South Africa. We're always interested in dinosaur bones. Yeah, so this is really exciting. Back in 1978, some scientists classified a bunch of bones as Massos Pondolas, which is a really common dinosaur in southern Africa. They were like 20 feet tall, mostly herbivores, very cool. But British scientists were recently re-looking through those museum collections,

and they thought something was kind of off. They found this one skeleton, a skull specifically, that was really boxy and compressed, whereas Massos Pondolas tends to have a sort of elongated skull, and they were like, you know, we need to look into this. And in a new paper, they determined that it's actually a new species, which is called Negwervoo Intiloko, which in the local Kausal language, which means gray skull. So a new species just hiding in plain sight.

Wow. So, you know, we know the fossil record. It gets reexamined all the time. What is so special about this case? So the really exciting thing is that this actually is not only a new species, but they think it's a new genus. And what that means, as you probably remember, a genus is a higher order of taxonomy. And so it means that there could be more species underneath this genus, just like in Guervut and Floko. So now they're two. trying to reconsider a bunch of different pieces of Massos Pondolas and wondering if these might be reclassified as an entirely new kind of dinosaur. Wow, that is kind of exciting and unusual, isn't it?

Definitely. Yeah. Moving on, there was a really sobering study out this week that showed that more than 1,500 people have been killed in the last 15 years for defending their environment. Tell us about that. Yeah, this was definitely, I think, surprising to a lot of people and very troubling. So a new study in nature sustainability reports that between 2002 and 2017, an estimated 1,500-plus people were killed for defending their environment.

So that means trying to stop things like dams or logging and defending natural resources. And that's actually more in that same time period than the number of service members from the United Kingdom and Australia who were killed abroad in war zones in the same period. which means that environmental advocacy is more dangerous than anyone really thought. Tell us, give us some details on this. Who are these people? Why is it so dangerous? What were they defending? So the people involved are actually really widely varied. Many of them are activists, but there have also been killings of journalists and lawyers who have been involved in environmental issues.

It really seems like in some areas, if you go up against the wrong people, no matter in what capacity, you put yourself at a risk. So it is something where you're most at risk in countries that have sort of corruption or weak government. It's highest in Central and South America. That's where the most people have been murdered. And it's not, you know, just these people on the picket lines. It's really anyone involved in any capacity. And they're often killed, unfortunately, by the people who are doing the extraction.

So miners, loggers, and sometimes even the police and military are involved in these crimes. So we're talking about advocates then, like lawyers and journalists, as you say, people who are standing up for the environment? Right. So Bertra Caceres is a really great example of this, unfortunately. So she was an indigenous Honduran activist, and she tried to stop a dam on sacred land. And she was brutally murdered by hitmen who were actually hired by the dam company because they felt that she was causing, you know, too many delays in their project timelines. And so what might be – well, how can we ministering it? mitigate this? What can researchers do or what can they suggest be done?

So the suggestion here was basically that companies and countries have to be held accountable. So they found that only 10% of cases are actually pursued by the court, which is an extremely low percentage. And so basically people who carry out these crimes feel a sense of impunity. They know that they're not really going to be pursued for what they've done. So, you know, create an example of if you kill an environmental activist, you are going to be taken to court is what these authors were recommending in their paper. There is one of my favorite meteor showers coming up. Comes up every August.

It's a great one. Coming back next week. Tell us about that. Yeah, the Perseids are back. So they come around every year. They're one of the most beautiful and prolific meteor showers in the northern hemisphere. It's really exciting. They're going to be peaking on Monday, August 12th, and Tuesday, August 13th.

So you should definitely get some coffee, stay up late, and head out to a place with low. light pollution because the show is on. And this is kind of a fun event to have. Have you ever gone out and done this? This is really a fun thing to do. You go outside, you can lie down on the top of your car, the hood of your car, or you can get a chaise lounge out, lie down on your back and watch the sky. It's fun.

It's the right kind of temperature and everything. Yeah, the temperature is going to be perfect for it in a lot of the northern hemisphere. Yeah, and you just have to make sure that you give yourself time for your eyes to adjust because it definitely is difficult to look into that dark sky and see things. So give it about an hour, and then you should be in for a really good show. And, of course, it's always a great time to look at the planets. You can see some great views of Jupiter and Saturn now. And speaking of the planets, I want to bring in one more bit of space news.

Scientists think they found evidence of a tsunami on Mars. Is that right? So, yeah, we all know what the Mars looks like today. It's red and dusty. But scientists have been debating for a really long time what it looked like about 4 billion years ago. So some think that there was once a giant ocean and others think that it's always been a pretty icy place in the northern hemisphere. But the people who think that there was an open body of water just got a big boost because scientists have identified a 75 mile wide impact crater that looks a lot like the one in the Yucatan on Earth that triggered the extinction of the dinosaurs. And so they're saying this looks like it crashed into an ocean and kind of reshaped the surrogate.

of the planet. That is exciting. Thank you, Eleanor, Leonard. Great stuff. Eleanor Cummins, Science Journalist based in New York. Thanks again. Have a great weekend. Thank you.

We're going to take a break when we come back. We're hopping on board an icebreaker in the Arctic to study summers in that rapidly warming region. We'll be right back with the trip to the Arctic. Stay with us. We'll cool off. This is Science Friday. I'm Ira Flato, the Northwest Passage, that Arctic icey shortcut between the Atlantic

and Pacific Oceans. It's, you know, it's all one. fascinated people. Inuit communities in the area have traveled the waterway for millennia. Remember your explorers? John Cabot, Henry Hudson, they set sail for these frigid waters looking for new trade routes. And now you can even take a vacation cruise through it. But one of the latest expeditions to the Northwest Passage had a different mission to study the science of the rapidly warming Arctic. Last month, a team of oceanographers, marine biologists, ice and students boarded the Odin, an icebreaker boat, and began an 18-day expedition through the passage.

Now, last year, if you remember, the team launched, but they were grounded one day into the journey. They had to cut the trip short, but this time the expedition made it all the way from Greenland, along the northern coast of Canada, through the Barrow Strait, and out to Melville Sound by the Arctic Ocean. Team returned to Greenland this week with lots of observations and a lost buoy they recovered that holds a year's worth of whale songs. We're going to talk about some of that, all of that. My guests are here to take us through that expedition. Bryce Luce is the chief scientist of the Northwest Passage Project,

Associate Professor of Oceanography at the University of Rhode Island in South Kingston, Rhode Island. Welcome to Science Friday. Hi, Ira, thank you. It's great to be back just about a year later. And Holly Moran is a marine biologist and education specialist also at the University of Rhode Island. Welcome, Holly. Hi, Ira. Thanks so much for having us today.

Yeah, it was nice to have you. I'm glad you had a successful trip this time. A little longer than last time. And in your last visit, we talked to you last year right after the boat ran aground, what's challenging about navigating through the Northwest Passage, even on an icebreaker boat, Bryce? So I'd say the challenges are the same as they were last year. Invariably, you encounter ice conditions that are probably not optimal for navigating.

And even with an icebreaker, especially in an environment like that, the captain gets nervous because you're having to navigate through ice, which is being pushed around by the wind. But then you've got some really narrow shorelines. And so the captain's nightmare scenario, the boat is being pushed by the ice and it's eventually drifting towards the shore or into shallow water. And all these are the factors that they kind of take into account when they figure out where we can go and what we can do. In that regard, we did have some of that this year, but at the same time, we were up there early, but the ice is also retreating early,

which is another impact of what we saw. And so it kind of in a way was retreating as we were advancing. So we had quite a run before we finally ended up in the ice. Did you notice anything immediately different, Price, than you were expecting to see? Well, I mean, frankly, I'll just say that compared to my previous trips to the Arctic, the weather was just uncannily pleasant. Like the temperature really never dropped below zero degrees. We had a record number of sunny days.

The wind was really low and very calm. honestly, we were outside sometimes, you know, working in T-shirts. The students have been posting pictures to Instagram and their Hawaiian shirts on the back deck of the Hilo where the helicopters land. So I think the really outstanding thing was that it was quite warm in the Arctic. Yeah, I think there was one day, actually, where we were 57 degrees Fahrenheit, I think. It got quite warm. I started my broadcast, you know, in my usual full, you know, heavy-duty float suit. And then by the end of the day, I was just in a fleece jacket and short sleeves, and that's it.

So it was a pretty spectacular swing in temperatures just in that one, you know, 12 to 15-hour period. So that's actually the good news and the bad news, isn't it? It is. I mean, it makes it lovely to be up there. Because that's something you're trying to study with the effect of that warming that's going on up there. Yeah, indeed. We're trying to basically see how it's impacting the water, how it's impacting the water, how it's impacting the gas burden, both of methane and carbon dioxide that we see in the water, how it's

impacting the microscopic communities, basically the plankton that photosynthesized and provide the base of the food chain. And then, of course, we're trying to see how the rate at which ice loss is kind of moving into the ocean and how that's freshening the ocean and how that's moving around. And then if you look at, if you take all those factors and then you build that up to the seabird surveys that were being conducted as well while the ship was underweigh, way. It's a great way to see if, you know, what seabird species were in the area. They're what we call an indicator species. So oftentimes you can see if there's a change happening in the environment

based on what the seabirds are actually doing where they are, what they're eating. So by tracking those species and seeing which animals were where in certain numbers, it's nice to put all those different puzzle pieces together and kind of get an overall picture of the environment that we were in. Let's talk in detail a little bit more about that, Bryce. Let me ask you first about the microbes that you study in the water that eat methane and the part they play in greenhouse gas cycling. Tell us about that. Okay. Yes.

So we have been for a while, I'd say for the last 10 or 15 years, trying to figure out what exactly is the story with methane in the Arctic. We know that there's quite a reserve of it. Mostly it's found in the seabed in the form of these methane hydrates. It's like an ice crystal that sits on the ocean bottom. And you can bring it up and actually light it on fire. it will burn because it has enough methane in it. And so that's stable at certain temperatures and pressures.

And we know that actually since the last ice age, the ground has been rising as a result of rebound because the ice sheet melted away and that took a large weight off the continent. And so just as a result of that, we've seen more methane like venting from the seabed. And what's interesting is you can observe the methane venting from the seabed,

and you can create an inventory based on that, but when you go to the atmosphere, which is where we'd expect that gas to end up, we just don't see the gas there. It's not making it across the interface from the air to the water or from the water to the air. And so the question is, if we try to balance the budget,

where is the missing piece? And one idea is that it's actually the microbes, the bacteria and archaea, of which there are between 10,000 and a million in each drop of water. Could be eating this as a food source, essentially, and turning it from methane into carbon dioxide. Well, as the oceans warm, as the water warms,

are those bacteria going to disappear themselves, the ones that recycle the methane? That's a good question. I think one thing that we have seen and what we see is that basically, it's kind of like an if you build it, they will come scenario with bacteria. So during the deep water horizon oil spill, for example,

there was a tremendous microbial response to the oil that was released at the subsurface during that event because they were adding dispersants to the oil as it would rise, and that caused it to sort of detrain at about 3,000 feet. And at that same level, the oxygen was drawn way down. And when we started to do, when the scientists started to do genetic analysis, they basically found a large abundance and a very rapid response of oxidation of hydrocarbons, including methane. So, I'd say these guys are relatively ubiquitous. They're tolerant to a lot of different conditions. The ones that are in the Arctic are designed specifically for cold conditions,

so they may not do specifically that well, but the genes that they carry, which allow them to oxidize methane, those will probably be there. And in fact, they operate much more quickly when the water warms. Holly, you're a marine biologist and coordinated some of the animal studies. Tell us what types of animals you saw while you were up there. We were actually pretty lucky from what I've gathered from other cruises that have been in the area and that we saw pretty much all of the marine mammal species you would expect to see in the Arctic.

So we saw about 20 maybe polar bears were treated to some moms that had cubs as well, and they were all out on the ice floes. We saw bowhead whales. We saw a pot of narwhals. We saw beluga whales outside of Beechy Island. those we saw from the helicopter. We saw Walrus. We saw

all different types of seals. My favorite seal is the bearded seal. They have these fantastic array of whiskers in the front that look like a mustache or a beard, and that's why they get their names. But they kind of escorted us out. They were on the individual pieces of ice as we left an area called pond inlet.

And so it was great to see this diversity. It was kind of a treat, and if you wanted folks to join you on the bridge, you know, that top deck where the captain was, all you had to say was polar bear, and it was like a stampede to the top of the boat. And there was, just to let you know, I want to say there's nine decks, some 96 stairs from the bottom to the top of the ship. So people were trucking it up these stairs to come see, you know, when they were animals cited. It was pretty great. And you had a lot of students with you, too, right?

Yes, we did. We definitely did. We had a group of 18 undergraduates that were from minority-serving institutions from across the United States, which was great to have them on board and get. them engaged and exposed to actual science happening on board, a research vessel, let alone an icebreaker. And then we also had graduate students that were participating as well. And they were acting as the student leaders for each of the core research groups so that they were helping guide the undergrads with their work that was happening on board the boat. I can imagine it was a pretty crowded bridge by then with everybody up there. Yeah, it was a pretty big bridge, though. We all kind of found our spot.

and there was an outside deck if you wanted to be out there as well. Or some people would just go out to the front of the ship and look from there as well. But yeah, it was a surprisingly spacious, you know, but still we were all close-knit family type thing on that boat. It was a nice thing. I think the calm, Swedish sensibility and demeanor played in well there because they're so stable and mild-mannered. And they were quite happy to host us all on the bridge and entertain the questions from the students. and so it's a very warm and welcoming crew aboard the icebreaker Odin. Yeah, they welcomed the students.

That was the best part is the students really became part of that ship. It wasn't just the research they were doing. They really got to understand how that ship was functioning and how important it was. Cold water, you're in Swedish environs. They're used to that. You also worked with the local communities up there to get their observations about the area. What kind of changes were they observing, Holly? Well, we were able, what we did was we went into the community that I mentioned called Pond Inlet.

We were able to have a barbecue with them one evening, which was great. Food security is actually a big issue in a lot of Arctic communities. It's hard to get food up there. It's expensive. So we were happy to host a barbecue with them all. And then we were able to speak with many of the locals at that point in time. But we returned the second day with a group. We had tour guides from a group called Ecarvic, and that's a local research group that they are actual local.

scientists there in Pond Inlet that are doing work, doing various research projects, but then they try to work with other scientists from the lower 48 or other countries that are interested in doing work up there to kind of bridge the gap between traditional Inuit knowledge and then modern-day science per se. And the interesting thing was when we brought them on board the vessel, and we had actually made a really interesting, well, we thought we made a really interesting seabird observation when we were transiting from Tully Greenland, Rick Lugkin, who was our observer from the Canadian Wildlife Service, I'd seen a sooty shear water, and that's a bird that you traditionally see on the northeast coast of Canada. I'm used to seeing them here in New

England, but they're not usually up in the Arctic. So Rick made note of that, and then when we talked to the folks from Icarvik, they said, oh, we see city shear waters all the time from here. And we were like, really? They're like, oh, yeah, for at least the last five years, we've seen them all the time. So Rick made note of that, and then was going to share that with our contacts at the Canadian and Wildlife Service to then talk further with this group in Pond Inlet. And it's just kind of a nod to the fact of how much knowledge these Arctic communities do have and how important their perspective and the details that they've been keeping on their own are so important. Interesting.

And to make sure we consider those and incorporate them as we continue to do research up there. Very, very interesting. I'm Ira Plato. This is Science Friday from WNYC Studios. Talking with Bryce Luce and Holly Marron about their Northwest Passage project. And Bryce, I mean, you found, you take ice cores, right? I understand that you found microplastics in the ice cores in the Arctic. Yes, that's correct.

I don't know what to say about that. Yeah, I don't think we knew what to say exactly either. Objectively, we knew that this was a possibility because similar plastics had been found in ice cores in the Central Arctic, in the even further north in the Eurasian and Canada Basin. So that's actually how we determined that we would try to make these measurements. We were sort of following in the footsteps of the researchers who'd map that out. And we said, well, maybe we can contribute just by looking and seeing what's in the Northwest Passage. And I think that the shocking thing for me was we went out to this beautiful, what's called a multi-year ice flow.

So it's an ice flow that's managed to survive a summer and freeze again, you know, basically live another year. And so it's thick. It was almost 10 feet thick and we had to core it in multiple sections and then we brought it back to the vote and Jacob Strach and Alessandra, Dianjula, those are the two the researchers who were leading that part of the work. They went through some steps to concentrate the material inside the ice and they were worried initially that if they didn't concentrate the entire core, they wouldn't be able to see anything. But as they began the concentration steps, they actually realized that there was so much material in there, that then they had to sort of break it out into sections.

And what was remarkable, and I think maybe a little bit of a shock to all of us, even though objectively we were expecting it, was that the amount of plastic, basically these filaments that show up at the sort of the millimeter to micron scale, as well as around beads, almost like the microbeads that show up in shampoo and exfoliates. body wash, those kinds of things were really abundant in the ice, much more abundant than in the water. And maybe you could even say of equivalent abundant as the microbes that we often see in the ice itself. And then they could see the, if I remember correctly, they could see the microplastics with the naked eye. They didn't have to just look through a microscope to see

them. Yeah. Yeah. So, you're saying they were as abundant as the algae was in the water. I mean, and I don't want to make too strong a statement of that because we haven't actually done the counting. So we have to go through some sequential steps that we couldn't take place on the ship. But we were initially worried that there would be so much, so many algae and so much, like, biotic matter that we wouldn't even see the plastic. In fact, the plastic was like in every layer was just as abundant and just as visible. So it was quite high in concentration. But again, I want to reinforce it. It was much lower in concentration in the water below and adjacent,

so I think what we see is that the sea ice is, as it is for many things, it's a concentrator of the plastic material because of the way it both can trap stuff through atmospheric deposition, so stuff that's wafted in on air masses that come into the Arctic, but also through the way it actually filters seawater through this siphoning. pump mechanism that exists throughout the life cycle of ice. So once it gets in there, then, of course, it's also trapped.

It's kind of frozen in place. And that's what we saw. So much more to talk about. I wish we had more time. We'll have to have you come back and talk more about this. Bryce Luce and Holly Marne, both of the Northwest Passage Project

and both that of the University of Rhode Island and South Kingston, Rhode Island. Thank you both for taking time to be with us today. Thank you. Yeah, thank you. It's a pleasure to talk to you. We're going to take a break, and when we come back, we're going to talk to birds,

and birds see the world in color even better than we do, how their supervision might shape their super colorful feathers. Oh, interesting stuff about how birds see and how their feathers actually make those colors. We'll talk about it after the break. Stay with us. We'll be right back. This is Science Friday. I'm Ira Flato.

Our book club is mid-flight this summer, reading Jennifer. for Ackermans, the genius of birds. If you've been following along, you know we've been learning about some of the many brilliant tricks birds have, from impressive tool-making talents of crows to elaborate feats of artistry and the Bowerbirds of New Guinea. We asked you on our Science Friday Vox Pop app whether birds like Bowerbirds can be artistic. Peter Barber in New Zealand thought yes if we just think what our art is.

Birds can be artistic. I'm a musician. It seems to me that all forms of art, be it music or dance or sculptor or painting, they seem to me to be forms of courtship display. So there you go. I think birds are doing the same thing. Another test of bird artistry. How about themselves? Birds are some of the most colorful creatures on the planet, from the dazzling iridescent displays of hummingbirds to the many-hued birds of paradise. But it turns out that birds may even be more colorful than we thought, since their vision sees well into the ultraviolet range. And researchers studying bird feathers, finding there's more than meets the eye in bird plumage. Patterns only visible. in the UV range. And colors that look the same to us, but from a different bird's eye view seem quite different. That's all quite interesting stuff, and that's what we're going to be talking about with my guest. Dr. Mary Caswell Stoddard, assistant professor of ecology, evolutionary biology at Princeton University. Welcome, Dr. Stoddard. Thank you. And Dr. Allison Schultz, assistant curator of ornithology at the Natural History Museum of Los Angeles in L.A. Welcome, Dr. Schultz.

Thank you. It's a pleasure to be here. Nice to have you. Let me ask you first. What's so special about how birds see the world? Well, I can go ahead and answer that. Well, you know, as you just mentioned, birds see more than we can. So as humans, we have three types of cones in our eyes that can detect color, kind of red, green, and blue. And if we're talking, you know, what part of the electromagnetic spectrums,

we can see, we see from about 400 nanometers to 700 nanometers. But birds actually have a fourth type of cone in their eye, and this cone resides in the ultraviolet part of the spectrum. So from a bird's eye view, they can actually see down to 300 nanometers and all the way up to 700. And that fourth cone type actually gives them kind of, you know, four-dimensional, three-dimensional vision where we have somewhat, we could think of as two-dimensional color vision.

Does every bird have this? I would just chime in there. Yes, we think that this is a widespread feature of bird vision. We call this tetragrammatic. Birds have these four types of color cones or photoreceptors in their eyes. And a lot of times you might think that that just gives birds the ability to see all the colors we humans can see, plus some ultraviolet tacked on. But actually, we think that birds can perceive an extra dimension of color.

They have very interesting combination colors. like ultraviolet plus green and ultraviolet plus red, that we can't even imagine. These are very natural colors that we believe birds can perceive. That is just crazy. They've got the fourth another dimension that you can mix colors with, right?

Exactly. So they can create a crazy purple we can't see or some other thing. We need a new word for it because we don't have that color. Yep. That's right, and we do think that these colors exist. in the environment. As you mentioned, they are producing some of these special colors with their feathers, and we know that flowers have some of these colors in them, too. And so these colors

exist for these birds in their natural world. Okay. Here's a question I've thought about this. When did birds evolve this ability? I'm asking you this, because we talk about dinosaurs as being birds. Did dinosaurs have this ability also? Cassie, what do you think? Well, dinosaurs very likely had tetragrammatic vision very similar to modern birds. This type of visual system exists in many fish and lizards, and it is ancient. It evolved early in vertebrates, and we know now that dinosaurs, many dinosaurs, had feathers and probably very colorful feathers too. So it's not just that they had tetachromatic vision probably, but they must have looked more stunning to each other than we can even fathom. So do you think our mammal, human ancestors, had this ability,

but we lost it somewhere along the line? That's exactly right. We think that this ancient tetachromatic visual system changed through our own evolutionary history. Mammal lost two of the four color cone types, and it was one group of primates, the old world primates, that re-evolved a third color cone that gives modern humans the trichromatic or three-color cone system. that we enjoy today.

Wow, wow. So if birds see the world differently, does this mean they look different to each other than they look to us? It would seem that they do. Alison, do you want to take that one? Sure, yeah. So absolutely.

So, you know, birds definitely look different to how they look different to each other than how we perceive them. And that's actually shaped, you know, how we're studying, bird colors evolved. In the past, there was really a bias to thinking about how bird colors evolved from a human visual perspective. You know, we categorize things as what we think of as colorful, as we think of as drab. But, you know, there's a lot that we're simply missing. So, for example, I study a group of birds called tanagers, and if you were to look in field guides, you would

think that about 50% of tanagers or about half of tanagers, the males and the females are the same color. However, when I measured all these tanagers and kind of applied an avian visual model, so we model how we think birds are seeing each other, actually we think about 93% or almost all of them actually have differences between the males and the females that we simply can't perceive with our eyes. That's quite interesting. Our number is 844-724-8255. 844-7-24-8-255. You can also tweet us at Cy Fry. Now, color is often a really important part of how birds mate, right? Is this why they have this enhanced color vision, Cassie? Well, color is definitely seductive, and we think that many colorful birds have evolved these vibrant feathers to attract mates. We do some work in my lab on

the broad-tailed hummingbird in the Colorado Rockies, and they have spectacular, iridescent feathers that they use in their own courtship displays. And of course, some of the most charismatic birds that come to mind are using color. But there are other reasons to have plumage and feathers that have particular colors beyond mate choice. So they can be used for social interactions if birds are communicating their dominance in a group, for example, or it can be used for individual recognition. Of course, plumage can also be important for camouflage. There's a bird called the tarmigan that can, it can change color with the season, actually. So in the winter, its plumage matches the snow, and in summer, it's feathers of bolted,

it gets a new plumage in, and that matches the dirt and the rocky substrate. So there are many different explanations for why birds are colorful or why they are drab. Do we know why, as a rule, that male birds are more colorful than females? Is it just because of that mating attraction? Generally, we do think that, you know, what we've seen in almost all cases, males are more colorful females, and it probably is due to mate choice, you know, either to attract females or to have males kind of communicate amongst each other to kind of avoid conflicts of territoriality or to gain access to different resources. So, yes, for the most part, males are more colorful. Now, interestingly, there are some species where the roles are reversed, where females are actually the ones who are choosing, the males are choosing the females. The females might have multiple mates, and in those cases, actually the females are more colorful.

So, you know, we kind of see both things. But for the most part, it is the males who are more colorful. Cassie, you're looking at hummingbird mating displays as one example of birds using color in a really interesting way. What are male hummingbirds doing to impress the females? Well, the males that we study, the male broad-tailed hummingbirds, they perform these absolutely dazzling courtship dives to females. These males fly more than 50 feet sort of straight up in the air, and then they do a death-defying U-shaped dive over the female's head.

And you really have to see it to believe it. The first time I saw it, I almost fell over. But at the bottom of the dive, the males are going extremely fast, and they snap their tail feathers together to make a very loud buzz, and they show off their magenta, iridescent throat feathers. And in my lab, we've been analyzing these dives, and we've discovered that all of the action happens in about 300 milliseconds right at the base of the dive. And that's, if you blink your eyes, that's 300 milliseconds. So these males have evolved to deliver a sensory explosion of sound and color and speed to females right at the correct moment. Wow, that is quite, you know, I've been trying to attract hummingbirds for years. I've been successful, pretty successful lately, but I have not seen that dive maneuver.

I will have to look out for it. But one thing I do notice when I look at the hummingbirds is that the colors seem to oscillate. the way I could put it. You know, the colors seem to change eardescence a little bit as I'm looking at the feathers. What is going on there? Well, iridescence is a very special type of color. Birds can make their colors in many different ways. They can have pigments that they are producing inside their bodies or that they're obtaining from the diet.

Or they can have colors that are called structural colors. And in these colors, it's the interaction of light with the feather structure itself. that gives a bird feather a particular appearance. So a blue-jay blue is one type of structural color. And if you grind up a blue-jay feather, you'd just be left with black dust because you've disrupted the feather structure at that point. Iridescence is a structural color as well,

and that's where the appearance of the color changes with the angle formed by the light and the feather and the viewer's eye. And so that's what you're observing with hummingbirds, this sort of special angle-dependent kind of color. And if you were to dissect hummingbird feather and look under the microscope, you would see little layers of blobs called melanosomes packed with a black melon and pigment arranged in very precise layers. And it's how the light is interacting with these layers

that gives hummingbirds their iridescent appearance. Myra Flato, this is Science Friday from WNYC Studios. talking with Allison Schultz and Cassie stuttered about a bird color we have a we have some listeners who'd like to join us and we're always happy to have them let's go to Tony in Minnesota hi welcome to Science Friday hi thanks for having me a really interesting show yeah I had a question the the two speakers had earlier mentioned that this fourth kind of cone in these birds eyes allowed them to see another

dimension of color and I was I'm wondering if they can maybe unpack that a little more. Like, is that another spatial dimension, or is this just kind of like a new concept altogether? Thanks. Yeah, good question. Well, you know, when we say another dimension of color, it's kind of like, so if we think about where, like, a human color space, you can think about how hues exist in a two-dimensional space where you have kind of, you know, the proportions of red, green, and blue will make up a hue that we see.

However, with this fourth, when you add a fourth cone there, basically you're adding, you now have to turn that two-dimensional space into a three-dimensional space. And so there's, it's not simply, it's, it's hard for us to imagine because we, you know, we have our own sensory systems. But, you know, when I talk to people and try, you know, everybody always asked me, hey, Allison, could you make some sort of goggles or something that could make us sea like birds? And unfortunately, we can't because our brains are just not wired that way. But one thing I like to do is kind of take a picture and turn off one of the colors that we see.

So, for example, red. So if you turned off all red in a picture, it would be very different from what we see. And so you can kind of imagine adding a whole other dimension in that way. That's kind of the closest I can come up with. And in fact, we've had a question, a Twitter question came in that I was. wondering about is, is there a set of goggles or glasses or something that we could use to see what the birds see? Anybody make that?

As Allison mentioned, that is a pipe dream, but it's really more complicated than that, because we know that it's about how these four types of color cones interact with one another. And so we don't have the neurons to compute what these colors might actually look like, even if we could have goggles or a particular camera that can detect the UV. Now, even if we can't have goggles that really give us a bird's eye view of the world, we do have technology that allows us to capture UV-reflected light in the environment and in feathers. And that's something that we're working on in. in the lab, and I know Allison is doing work in this realm as well, and that's been a really exciting

move forward for our field, that now we can use ultraviolet sensitive cameras to go out and take pictures and measure where ultraviolet light resides. And we are finding in lots of bird feathers that there's hidden ultraviolet color embedded in plumage patches that we can use this technology to highlight. I just got about 30 seconds ago. One last question for Cassie. You also looked at birds' eggs. Is color important also in the bird eggs?

Absolutely. Birds lay spectacularly colorful eggs. My favorite is the emerald green egg laid by the emu, which is a large flightless bird. And we know that egg color can be used for camouflaged or thermoregulation, but it can also be really important for deception. So we work on a bird called the common kuku that sneaks its eggs in. the nests of other species, and it leaves all parental care to these host birds. And they're really ultimate freeloaders.

And these cuckus have evolved eggs that can precisely mimic the color and pattern of the host eggs, so the other birds weren't noticed. So they're really the forgers of the bird world. And if you want to learn something really interesting about color and deception, look up cuckoo eggs because there's so much cool stuff there. Cassie Stoddard, Assistant Professor of Ecology, Evolutionary Biology at Princeton and Allison Schultz, curator, assistant curator of an orthology at the Natural History Museum of LA. Thank you both for joining us today.

Thank you very much for having us. You can learn more about the bird vision and researchers working to digitize all these crazy plumage colors and a new article on our website, ScienceFriiday.com slash color, plus crazy about crows or ravens or other members of the Corvid family. Learn more about crow funerals, grudges, and other feats of intellect from McKayley Swift in a Reddit AMA. Ask Me Anything that's next Monday at noon Eastern. All that and more on our website at Science Friday.com slash book club. We'd like to thank all the folks here at Texas Public Radio. We've helped us get our program on the air today. Wayne Cobble, Rubin Garcia, the great folks at Texas Public Radio in San Antonio, who made us so welcome here today. And for you, Texas

folks in Texas, we hope to see it tomorrow night at the Tobin Center here in San Antonio. Still a few tickets left, ScienceFriday.com slash San Antonio. Until then, in San Antonio, I'm Ira Flato.