Lights Out: The Effects of Light Pollution on Bird Health

Lights Out: The Effects of Light Pollution on Bird Health
Aired April 12, 2023

Ashley Peery:
Hey everyone. Welcome to today's webinar. My name is Ashley Peery, and I'm an educator at Smithsonian's National Museum of Natural History. I am a Caucasian woman wearing a dark shirt, and in my background, you can see some framed images, as well as an image of a large, pink flower. On your screen, you are seeing an image of a magnificent star-filled sky, as well as the title, date, and time of today's program. This webinar is "Lights Out: The Effects of Light Pollution on Bird Health."

So welcome everyone to Shared Planet Shared Health. This is a monthly webinar series that explores the connections between human health, animal health, and the health of the environment, which is also known as One Health. This webinar is also connected to an exhibit that recently opened at Smithsonian's National Museum of Natural History. That exhibition is titled "Lights Out: Recovering Our Night Sky," and it's all about how the night sky and its disappearance due to light pollution affects all life on earth, from natural ecosystems to human cultures.

So if you find yourself in the D.C. metro area, that exhibition is up on the second floor of the museum, and it's worth a view. It's beautiful. It will be open up until sometime in 2025, so I hope that you can check it out.

Now whether this is your first time joining us, or you've attended a natural history webinar before, I'm so glad that you're here. And before we get started, I have a few housekeeping notes to go through. So first, today's discussion offers closed captioning. You can toggle those captions on or off using the CC button, which is down at the bottom of your Zoom interface. Second, we will be taking your questions today. We're going to take them after our speaker's presentation, but I recommend that you get your questions in as soon as you think of them. You can drop those into the Q and A box, which is going to be either at the top or the bottom of your Zoom interface. And the Q and A goes really fast, so get your questions in as you think of them, and we'll get through as many of your questions as we can when the Q and A time arrives.

We're also going to be sending some links to you during today's program. These are going to be links that are connected to the presentation today, so keep an eye out there. You may see some things come through during the speaker's presentation. And lastly, it's just a note about format. We're going to start with a presentation from our speaker, Dr. Valentina Alaasam. And then once she concludes her talk, I'm going to join Valentina on screen to take your questions.

So let's go ahead and introduce our speaker. Valentina has a B.S. in Biology from Virginia Tech, as well as a Ph.D. in Ecology, Evolution, and Conservation from the University of Nevada Reno. She's interested in how animals cope with the changes that humans make to our environment, and her dissertation research focused on the effects of light pollution on birds. She plans to pursue a research career investigating how urbanization affects avian ecology and evolution. In this field, Valentina is also committed to bridging the gap between humans and their environment and increasing diversity in STEM education. So welcome, Valentina.

Valentina Alaasam:
Hi, thanks for having me. I will bring my presentation up.

Cool. Thanks so much. I'm really excited to be here, and today, like was just said, I'm going to be talking about the effects of light pollution on birds. My goal is I hope everyone will learn at least one thing new today, and what I talk about hopefully will spark some good questions at the end as well.

So light pollution is something I think we've all experienced in some shape or form. It's becoming extraordinarily widespread, and we're probably pretty used to it. Maybe we hardly even notice it anymore in our natural environment. But imagine being a bird in this environment. Birds are particularly vulnerable to light pollution for a couple of reasons. First, there's so many species that live here in our cities. If you've ever gone backyard birding, you probably know this already. And even the ones that don't live here with us will use cities as stop oversights during migration. And most of these species are diurnal, which means like us, they're awake during the day, and trying to sleep at night. And some of these are also open nesters. They nest out in the open, kind of like this guy up here in the top left, which makes them particularly vulnerable to exposure to light at night.

And it's not just cities that are affected. Light pollution is really good at leaking outside of the city into natural areas. So we can detect light pollution now, even in our natural parks and conservation areas. And even under the ocean, it's able to reach aquatic life at the bottom of the ocean floor.
Most of the time when I'm talking about light pollution, I want you to know that it's actually really dim. So this is a photo from my backyard, Lake Tahoe, and this is southern Nevada, and it's more common for animals to experience sky glow, or this kind of dim glow that you see here than it is for them to be sleeping directly under a street lamp. Although it does happen for sure.

Some of the first evidence that light pollution affected birds actually came from observations at lighthouses. So people who are monitoring these lighthouses would count how many birds would show up on a given night because they were attracted to these lights, and so there are records from lighthouses going back to as early as the 1900s. But nowadays, birds don't just have the occasional lighthouse to worry about because these nightlights are really all over the place. And so one of the really direct ways that light pollution is harmful for birds is by causing building collisions because of this attraction they have to the light. And so you may know that skyscrapers are a hazard for birds. You may have heard about this, but it's not as well-known that a lot of these collisions happen overnight because they're attracted to the light coming out of those windows. And so this is a recent study, came out in 2021, that showed if we reduce the amount of light coming out of windows from cities by just 50%, we can actually cause 11 times less bird collisions because that light is really attracting them.

Light pollution can also be a huge problem for migrating birds because it causes disorientation. So many birds travel thousands of miles at a time, which takes up a lot of energy, and getting a little bit off track because you're disoriented by light in the environment can actually be a huge disaster. I like to think about what it would be like to bicycle across the country from California to Miami, and then realizing when you get there that you're actually in New York. It can be a huge disaster, especially for a species that needs a very specific habitat or very specific food sources in the place that they're trying to get to.

And there have been some great advancements in technology that tell us this information, that lets us track birds and understand how big of a problem it is, and what species might be particularly vulnerable. This is a study that uses weather towers. So this thing right here is a weather tower, and it uses radar to detect bird movement. Basically because of how fast they're flying, we know that it's not an airplane, and it's not an insect. And so from that, we can tell where birds are migrating, which is this graph up here on the top. And using satellite data, we can tell where light pollution is. And so using these two kinds of information, we can predict what species might be more affected, and where we need to focus our efforts to reduce that light.

So those are kind of the big scale patterns that we see birds struggling with all over the globe. But now I want to talk about how light pollution might be different for specific species of birds, and also in different environments because there's actually a lot of variation in how light pollution will affect different kinds of organisms in different places. First, let's talk about different species. So what are birds actually seeing, and is the light pollution that we see in our environment different from what a sparrow might be seeing or what an owl might be seeing?

And there's actually a lot of variation in visual systems and how animals perceive light. So for example, we see this beautiful rainbow because we have these photoreceptors that show us the red, blue, and yellow and combines to make this rainbow. And birds actually have a whole extra photoreceptor that detects UV. And this doesn't just add a little bit of extra color on the end of the rainbow. It actually combines with all the other colors, like in this Venn diagram, to create a whole set of colors that we can't even imagine exist. So just to show you what I mean, this is an artist's representation of what a plain black bird might look like to another black bird with this cool visual system, or what a very well-camouflaged egg might look like to the bird that laid it.
And as it turns out, bird vision is also really diverse just across different bird species, depending on where they live and what they eat. For example, hummingbirds get most of their energy from drinking nectar, and they pollinate flowers. So this group of birds is particularly good at detecting shades of red, compared to other birds. I have a colleague, Hannah Moon, who studies seabirds at the University of Hawaii, and she found that across very closely related seabirds who all kind of have similar lifestyles, you can even find variation. So there are some species that dive deeper in the ocean, and because they dive deeper, they're actually less sensitive to reds and to UV wavelengths because those don't penetrate the water quite as well. And so they don't really need to be good at that kind of color vision at those wavelengths.

And then there's also nocturnal birds, who are specialized for nighttime vision. And so these kinds of birds are much more sensitive to dim levels of light, and what looks dark to us, they can actually probably see very well. So this is one example of a tawny owl, and they are 100 times more sensitive to light than, for example, your average rock dove that lives in our cities. This is one of my favorite birds, the oil bird, and they live in South America, Ecuador, Colombia, and Peru. And the same light source to them would be 150 times brighter than what that owl I just showed you could see, which is 400 times brighter than what we can see.

And it's been found that a lot of these nocturnal birds, for example, the burrowing owl choose roof sites or places to sleep that are closer to street lights when they can. They're often found hanging out around light sources, and they've even been shown to shift their diet and start eating the insects that are attracted or found around light sources.

So now we've talked about how different species all have different vision and so might perceive light differently, but in addition, light pollution itself can look different in different habitats. So that's the next part here. We can think about how light in a forest, for example, might look different when filtered through a tree canopy.

And weather can also impact the light pollution in our environment. So there was a study conducted in Berlin, Germany that found when it's snowy outside, in addition, when it's cloudy and snowy, then light pollution appears a thousand times brighter than it does on a regular day. And we find the same thing, like I mentioned before, light pollution can penetrate and reach aquatic organisms under the ocean. And again, on a cloudy day, the level of light that reaches down there goes up by about 30 percent. And even though you might think the light that reaches the very bottom of the ocean is going to be very dim, we have to always remember that different species have different vision. And some organisms that live underwater have a very, very good ability to see in very dim light conditions. There are some crustaceans that can detect moonlight even 80 meters below the surface, just moonlight, because they use it as a cue to migrate up and down every day.

But you might be wondering, why am I talking about shrimp and aquatic organisms in a bird talk? Well, although birds don't live underwater, many eat aquatic organisms. And so in addition to directly affecting a bird itself, light pollution can indirectly affect birds by affecting its food. There have been studies showing that artificial light around harbors and around offshore fishing vessels like fishing boats will attract sea birds, and increase their feeding rates, and often change what they're eating.

And the same is true for birds that eat insects. Many birds eat insects, and those are also attracted to lights, but different species will be attracted to different kinds of light. And so for birds that have flexible diets, and they could eat whatever they want, maybe a lamppost is now a 24-hour buffet, where there's just a bunch of food, and they can go for it. But for birds who can't do that, who have more restricted diets and really need specific types of food, they might be at a disadvantage. I like to imagine, if anyone else in the audience is a vegetarian, you might be able to relate. It's kind of like being around 2200 fast food restaurants, but there's not really many options if you're a vegetarian.

And understanding how different organisms perceive light of different colors and brightnesses, this is all important because we actually have the power to decide what lights we put outside. And right now, many lights are being replaced. These older, yellower lights are being replaced by LEDs. And LEDs tend to be whiter, they have more blues in their spectrum. And because they're more energy efficient, we also tend to put them out at much brighter intensities, just because we can, because it's cheaper, and it doesn't use as much energy. And when we make the switch to LEDs, it's important to think about how that light is going to look in different environments, and which organisms, which animals are going to be more or less affected.

And even though I study birds, I think as conservationists and scientists, we need to consider how all organisms are affected because it'll lead to a chain reaction across ecosystems. And so I hope you take away that while light pollution might seem like a really simple issue, there are these tiny, little details about different species, what they see, where they live, what they eat. And all of this should go into our decision making about using light at night, picking the right color, location, and brightness. All of this is stuff to think about.

So now we're going to shift gears a little bit, from talking broadly about responses of birds in the wild and what we see across species, to talking about the individual bird and what it's doing to bird health. And this is what I study. Essentially, how does this work? Why are birds so affected by light? That's kind of my question. And to study this, we need to know a little bit more detail about bird vision specifically and how that works.

So if you can imagine this gray blob here is a bird brain, light detectors exist in the eyes, called visual photoreceptors. These are the same ones that give us color vision, but there are also photoreceptors in other parts of the brain, which are called non-visual photoreceptors. And these are not involved with seeing pictures, but they are involved with detecting light. So it's kind of like how plants have photoreceptors, even though they don't have eyes. Very similar.

And now I get to tell you one of my favorite fun facts about birds. So some of these non-visual photoreceptors, they sit right on top of the brain, near the skull. And because birds need to fly, birds have very thin bones with actual air pockets in them, and it allows them to be lightweight. But with those two pieces of information combined, what happens is light can actually go straight through the feathers and through the skull, and be detected by these photoreceptors on the tops of their heads, so that birds know what time it is even when they have their eyes closed. And this is why you don't see a lot of birds wearing hats because when these photo receptors detect light, it becomes a cue to tune the body's internal clock, and it basically tells the bird it's time to wake up, it's morning, and things like that.

And so this clock that gets its cues from light controls things like melatonin, which is a hormone that goes up at night and down during the day. We have it too. It also controls the timing of behaviors. So for birds, it's how they know to wake up and sing in the morning, or it's how they know that the days are getting longer, and so it's time to breed, or it's time to migrate. And it controls physiological processes, such as the cardiovascular cycle, or how our blood pressure goes up in the morning, and our metabolism starts cranking and gets us ready for the day. That's all because of this internal clock that is trained by light cues in our environment.

The problem is in this new environment, the birds' brains and bodies are responding to artificial light that doesn't actually mean it's morning, so I consider this pretty biologically confusing. And it's actually the same thing that we see happening in humans. This confusion with our bodies responding to light causes health problems in night shift workers, who are exposed to light at night at all hours. And so we know from biomedical research that shift work and exposure to light at night in humans increases risks of things like cardiovascular disease, and metabolic cycle disorders, depression, cancer. And a lot of these health effects are linked to not other things involved with shift work because I know a lot of things could explain that, but specifically light exposure because light suppresses melatonin at night, and that's a really important hormone, and it can lead to a lot of other health issues.

And so for my research, I study how light pollution is affecting the health of birds, and so I monitor their sleep and activity with these little automated perches that record all of their activity on a computer. And so I monitor their sleep. This is a graph of nighttime activity in birds. So you can see here in the first part of the experiment on the left side, there's almost no nighttime activity at all. So we've got days on the x-axis, and activity on the y-axis, and in the beginning everyone's asleep because I have not turned the nightlights on, but as soon as I turn them on on day 10, you'll see a lot more nighttime activity, which means the birds are sleeping less.

And then I also take blood samples to monitor their health. So like I mentioned, we see a bunch of these health impacts in humans. And so my research kind of investigates are we going to see the same kind of effects in our birds? And I take a little blood sample. This is a measure of a hormone called corticosterone; it's similar to cortisol, which humans have, which is a hormone involved in metabolism. And also, it's typically involved with stress because this hormone gets elevated when we're stressed, for example, if we haven't been sleeping very well. And what I found was that after light at night exposure, the birds had higher levels of this hormone at the end of three weeks.

Another thing that I study is how the color of light might make a difference. So like I mentioned before, LEDs have become more and more the norm for choosing light bulbs, but they actually come in this range of different colors. You don't have to buy the pure white, bright lights. You can choose LEDs that look more like these old-fashioned lights, and so you'll see these options the next time you go to Home Depot. They're pretty common. But if you remember these non-visual photoreceptors I was talking about before, they're actually more sensitive to short wavelength light, the blue wavelengths. So although I mentioned before how much variation there is in visual photoreceptors and visual color vision, these non-visual photoreceptors are actually very similar across all different kinds of organisms. Us and the birds, they're all more sensitive to short wavelength light.

So this is why, like I mentioned, we have very similar photoreceptors, and so you might have heard about these blue light blocking glasses. That's why they've become such a thing is because that blue shorter wavelength is more stimulatory for those photoreceptors, more effective at suppressing melatonin, and so it's better for us to avoid that kind of light, either by having your phone filter it or by putting on some of these blue light filtering glasses if you have lights on or you're staring at your phone late into the evening.

So we tested these two kinds of LEDs on our birds, a warmer one and a cooler one. And what I found was that under the warmer colored lights, we see that their sleep is much less disrupted. And we also found that this hormone I was talking about before that's involved with stress is not as elevated. So under the cool colored lights, we're seeing those effects, but under the warmer ones that look more like the old-fashioned lights, we aren't seeing any of these effects.

And again, I think these health effects are interesting because they're very similar to the effects that we see in humans. And it's not just night shift workers who are affected, who are awake all night under these bright lights. This is kind of what my house looks like at night living in Reno, and I'm sure anyone who lives in a city or a suburb can probably relate. There's really just nightlight everywhere these days. And so I think this really ties in well to that one health understanding because the impacts that we see in our birds and the potential health effects that we see for our wildlife are also the same ones that we may see in humans.

So for the last little bit here, I want to talk about what we can do as humans to help minimize these effects in birds, and wildlife, and also for ourselves. And I've come up with four Rs that I'm going to talk about today to help you remember just easy things that we can do. So the first one is replace. And I mentioned this just a second ago. So like I said, LED light bulbs are becoming very popular, but when you're going to buy those light bulbs, we can make a huge difference by just choosing warmer color temperature lights, instead of these bright white ones. And that's something that I found in my own specific research that just switching the color of the light bulb can totally erase a lot of the impacts that we're seeing in the birds.

The next one is redirect. So make sure the light that we're putting in our environment is going where it's intended and not anywhere else. For example, we can use lamp covers, so little covers that will point our street lamps down at the sidewalk or the street where we need to see, but not up and out into the environment.

Vegetation can also be a great barrier. So if we can plant more trees along our roadsides and kind of block that light that we use for driving from getting out into nature, that can be very effective. And then the last one is curtains. This is probably one of the simplest solutions I've ever heard to anything ever because we already have them, and we probably already use them, but curtains can make a huge impact. If you remember that study that I talked about way at the beginning, if we can reduce the amount of light coming out of buildings at night, we can actually reduce bird collisions by 11 times. So using curtains and getting your businesses, or apartment buildings, or anything in your environment to just draw those curtains at night when people are working late can make a huge impact.

The next one is reduce, so this can mean reducing the amount of light by changing the timing of lights. So many cities have adopted policies to reduce light night during peak migration periods in the fall or during breeding in the spring. And this can make a big impact because light can have more severe effects sometimes on baby birds or on birds that are trying to incubate their young and attend to their nests. It's a really critical developmental time, and so if we can reduce light during breeding or during migration, that can make a huge impact. On a smaller scale, we can use motion sensors and things like that in our daily life. So perhaps you want a nightlight outside of your front door, so you can see your keys when you're getting home late, but have motion sensors so that that light only turns on when you're there, and it turns off the rest of the night. No need to have it on constantly.

And then we can also reduce the intensity of the light that we use. So like I mentioned again earlier in this talk, when it's snowy or overcast, the light in our environment gets amplified by this reflective quality of the snow. And so if we can have snowy day or cloudy day adjustments, and turn off some lights because we don't need them, even full moon adjustments when there's natural illumination, that can make a big impact as well.

And then finally, I think one of the best strategies is just to remove night lights if we can. So this is a picture of Reno, where I did my Ph.D., and I've been living here for about six years. And I can tell you there are so many lights that I think we thought were a good idea back in the day, advertisements were fun and exciting, but now that we know that this light can have health impacts for the wildlife and for ourselves, I think we can do a lot by just advocating to our local governments, local employers to turn off lights that aren't really necessary for safety, turn off advertisement lights when we don't need them.

And oftentimes there's a lot of redundancy. So if you see outside in your community that there are a bunch of streetlights, and some of them are shining light on the exact same areas, then maybe we can turn off half of them and still have lit up streets and sidewalks where we need it. And the best part about this particular strategy is that it saves us all money and energy as well. So I challenge everybody to go to your local governments, call people, policy makers, talk to your employees or your apartment building managers because I think in the end, it's a win-win. We're all going to save money by having lower energy bills, we'll be using less energy, so we'll have a better carbon footprint, and everyone will be getting a better night's sleep.

So those are my four solutions to remember. But then at the end, I do want to add just one more from my own personal perspective, and that's more research. So I went through a lot today. I'm sure it was a little bit fast, and I hope I get a lot of questions, but I just scratched the surface of what we know because there's so much that we still don't know about different species' visual systems, different bird species, but also just different animals and plants that are affected by light. And there's a lot more research that we can do that might develop new technologies and new kinds of lights that are less disruptive. So the more research that we do, the more answers we're going to get, and the better we're going to be able to make positive changes in our world. And with that, thank you for having me, and I'm happy to answer questions.

Ashley Peery:
Thanks so much for that. That was wonderful. You're right. There was a lot in there, and we do have some questions coming into the Q and A box. You want to dive into those?

Valentina Alaasam:
Yeah, that sounds great.

Ashley Peery:
All right, so let's dig in. Our first question comes from Michelle. Michelle says, "I'm interested in becoming an advocate for light pollution reduction in my condo complex. I anticipate there may be pushback from those who have safety concerns and possibly vision issues." Michelle wants to know, "Do you have any recommendations for how to engage in discussions with people who may have these types of concerns?" She also notes, Michelle used to live in Tucson, Arizona, a city that is very sensitive to light pollution, and that's where she truly saw the difference between cities that address this issue and cities that haven't critically examined it, and she wants to bring some of that Tucson energy to her current city, which is in Canada.

Valentina Alaasam:
I love that. Yeah, I love Tucson for that reason. They've done a very good job having darker skies. So this is a great question. I think a lot of people get nervous when I say turn off all your lights, and it does take a little bit of going outside your comfort zone, I think. It's hard to have more of that research; it's hard to turn off lights and measure things like crime rates because no one wants to take that risk. So places like Tucson are a good example. There are some cities who have reduced the light pollution in their environment, and they're still bright. There's still tons of light. But you'll see in those cities that crime does not change. There's no safety issues involved. And there have been a few case studies that did actually measure things like that by turning off lights, and it doesn't really affect safety measures at all.

But it's hard to convince people. I think we all get used to it, and we get used to seeing, and it makes us feel comfortable. So I think for your apartment complex or for anyone who's trying to be an advocate, things like motion sensors can be really effective. So try to get them to install motion sensing lights, so that when you're walking on the sidewalk, you'll always have a place to see, but otherwise they're kept off.

You can also advocate for things like curtains. So if you want to have lights on, for example, in the hallways in your apartment, so that people don't trip over things or fall down the stairs, have those lights on, but make sure you're using curtains, so the light doesn't get out of the building. And if you must have lights on outside, try to make them less bright. Have those shields that point them down, or use maybe ground lights as well, and use warmer color temperature lights. I can't speak for all animals, but I think the yellower lights are definitely less disruptive for the birds and for ourselves. And so all of those things that I mentioned before, so changing the color, pointing light downwards, and having timers on those lights can do a lot. And then people don't really have to sacrifice their ability to see.

Ashley Peery:
I mean, your answer just gets at how complex it is. There are birds, there are insects, there are aquatic organisms, so many organisms that can be impacted by light. So to move on to the next question, Aaron says, "Thanks so much for the presentation. You mentioned how burrowing owls will nest near streetlights given the chance. Are you seeing any other behavioral or physical adaptations emerging from light pollution?"

Valentina Alaasam:
Good question. So the biggest one that we see is nighttime activity. And we're not sure if this is evolution happening, or if it's just that things are kind of adjusting in the moment to their environment. I know for some other urban stressors, for example, there was a really good study that came out recently during COVID when nobody was driving anymore, and so noise pollution went down a whole bunch in San Francisco. And so some colleagues of mine just measured this, and they realized all the changes. We were seeing that city birds had different songs. They were singing at a different note to try and be heard over car traffic, but as soon as everyone stopped driving, their songs went back to normal. And so some of these changes that we're seeing are just kind of flexible like that, but we are definitely seeing effects. So one of the biggest ones is nighttime activity.

We're seeing that birds are waking up earlier, they're going to bed later. Some of them are just out foraging, hanging out all throughout the night. I've taken a few all-nighter type things during my research, and you'll just hear birds out there in the middle of the night for no reason. I think that's kind of new. The other one is... Well, and then I guess linked to that, what I study is hormones. So these lights can suppress melatonin, and they can increase the stress hormone that I talked about, which can have a lot of other repercussions. So a lot of hormonal changes and different physiological changes. In my research, I didn't get a chance to talk about it, but we also found that for the males under light pollution, their hearts were enlarged a little bit at the end of the experiment, which is very interesting. And I think it might be linked to cardiovascular issues, things like that. So there are a lot of little health effects that we're still trying to figure out what's going on.

But the other one that I think is very well-documented now is shifts in diet. And this might be a light pollution thing. It might be that, like I said, certain insects are attracted to lights, and so we're getting shifts in the insect community and the food availability of things in cities because of light. It could also just be a thing about cities in general. So there's a lot of things that we're putting out into our environment now that the birds are eating that's new. Bird feeders, fast food restaurants, trash. But it's hard to detangle all those things because wherever there's light, there's always also people and all the things that people bring. So it's hard to say for sure without doing kind of controlled experiments like I do what's really an effective light, and not just cities being cities. But yeah, those are I think the biggest ones that I know of.

Ashley Peery:
Thanks for that. Again, another indicator at the complexity here.

Valentina Alaasam:
Yeah.

Ashley Peery:
Our next question comes from Steve. Steve has a question about the U.N.'s Convention on the Conservation of Migratory Species of Wild Animals. He wants to know how effective are those guidelines to address light pollution on migratory species? Is that something you can speak to?

Valentina Alaasam:
I actually don't know about those guidelines, but I will definitely look into them. That sounds great. I know some broader policies within different cities. There are a lot of policies, and I think that does a lot. We were talking about Tucson earlier, but I haven't heard of global, U.N. kind of policies.

Ashley Peery:
All right. So while we're here on the topic of policies, Sherry asked a similar kind of question, but it's about LEED standards. She asked, "Do LEED standards comport with international Dark Sky Association lighting recommendations?" What about that one?

Valentina Alaasam:
Yeah, I also don't know about LEED. Yeah.

Ashley Peery:
Okay.

Valentina Alaasam:
Sorry.

Ashley Peery:
So I seem to remember that we had a resource we were sharing with the audience about the International Dark Sky Association and some of the recommendations they have. That might be a place where you guys can click and see what's there.

Valentina Alaasam:
Yeah, great point. So yeah, the International Dark Sky Association has a ton of resources on their website, and they have a lot of information where you can get rebates for putting up better lights, or things like that. So I'm sure a lot of that information is available there.

Ashley Peery:
Cool. So more to learn there. Okay. Someone ... Who's next? Next we have a question from Mark. Mark is asking if you can expand a bit more about the impacts of light pollution on migration.

Dr. Valentina Alaasam:
Sure. Well, like I said, so I think one of the biggest things that we're seeing is probably due to this attraction to light, or just general disorientation. So when it comes to attraction, we see a lot of birds that are, instead of just taking their normal path, they're kind of shifting, and going and stopping in a city instead. And we know that this can be a problem because sometimes we'll see mass die-offs of a huge flock of migratory birds that will just hit buildings and die in a city, and that gets a bunch of news. Sometimes it's not as dramatic as that, but we are seeing changes in movement, and we know that by putting little radio trackers on birds and, like I said, using satellite data, and these towers, and figuring out where they're going and seeing a shift.

And then the other thing that we're seeing is general disorientation. So there have been some lab experiments that have shown that birds use star maps in order to navigate. And so I think probably this light pollution, because it is kind of covering up the stars that we can see, it's probably affecting their ability to know where they're going. And so some of it is due to this attraction, some of it's due to disorientation, and then other parts, it can also affect the timing. So like I mentioned before, birds are kind of waking up earlier and staying up later because that light cue that's supposed to tell them it's time to wake up is not working quite as well because there's all this light there naturally that isn't the sun. And the same thing can cause birds to migrate earlier. So if they're waking up earlier and sleeping later, they're probably feeling like it's summer. The days are longer, and it's time to go.

So that kind of thing can affect the timing of when birds migrate as well. And yeah, there was a really cool video that I meant to show, but it was like... I have a colleague who put little trackers on nestlings, and for their first flight, they're supposed to fly out into the ocean, but because he put these little radio trackers on them, he could track their movement, and instead of flying straight out into the ocean, they would fly almost there, and then just detour into the city because the light was there, and they just got confused. And I think that's a really good example of the direct effects of light, but it can also have indirect effects, like the timing, more subtle things that we're still trying to figure out.
Ashley, I can't hear you. You're still muted.

Ashley Peery:
Sorry about that. So thanks for expanding upon that. It's very helpful. The next question comes from Sherry, and she asks a question about insects. She says, "Given that many insects are crepuscular, which means that they're active at dawn and dusk, shouldn't we remove light sensors that turn lights on at twilight?" And she also has a follow-up. "Do you communicate at all with the lighting businesses that push uplighting?" So a couple of very different questions there.

Valentina Alaasam:
I'm not sure what's meant by, "push uplighting."

Ashley Peery:
Sherry, you can chime into the Q and A and give some clarity on that second part. We'll wrap it in.

Valentina Alaasam:
Yeah.

Ashley Peery:
Do you want to take a stab at the insect question?

Valentina Alaasam:
Yeah, and that's a great point. So I didn't have time to talk about insects. I think that's a whole other talk because sometimes, the yellower lights that I mentioned that are okay for birds, they might actually just be attracting a ton of insects. And if a bird isn't necessarily as directly affected by that color of light, but there's a bunch of new insects outside, they might just be up anyways because why not eat while you can? And so I think I'm hesitant to make suggestions like that. And the best thing is just to use less light. It's the best thing for probably all organisms across the board.

But I think using less light during dawn and dusk is a really good strategy. And I'm glad someone brought that up because I think at these hours, we also don't need it as much because there is still some ambient light, and it is a critical time point that organisms are using that queue. If you're crepuscular, it means you're using that queue to start being active. And if you're diurnal, it means you're using that cue to go to sleep. Or if you're nocturnal, you're using that cue to wake up. And so in that transitional time, the change in the brightness of light from day to night is a really important cue for a lot of things, and if we can avoid disrupting that part of the day, it can probably make a huge impact.

Ashley Peery:
Thanks so much for that. Sherry actually ... Or I got some clarity about uplighting. So it's the illumination of homes for aesthetic reasons where you put lights under trees and on facades. So are you aware of any communication of this very important science to businesses that are trying to sell this practice of uplighting?

Valentina Alaasam:
Yeah, no, we don't have a lot of that here in Reno. I mean, I can imagine. If it's an aesthetic kind of landscaping thing, it's probably more common in suburbs and places with more landscaping. I live kind of in the middle of Reno, but that's a really good point.

I think that's a really good example of something that is not necessary and may even be making a much greater impact than if you just had a light outside your front door. Putting a light directly under a tree is probably not great for the birds that live in that tree. So that's a really good point. And I think it is hard to have conversations like this sometimes when it's somebody's whole industry to make beautiful lighting art and landscaping choices, and people want to have beautiful yards. So I think it's a challenging conversation, but it just has to come down to what are your priorities, and if it's about safety, or whether it's about having a beautiful yard, or just thinking about what the impacts of that are. And most people just don't really realize that there are such impact. So it may seem like a tricky conversation, but often as soon as people find out that it's disruptive at all, they're just like, "Oh, okay. I'll just turn them off."

Ashley Peery:
So the next question, it's from David. David is interested, how do we learn who is responsible for replacing a streetlight? Let's imagine the conversation has happened, and someone wants to use the replace strategy that you mentioned. How do you find out whose job it is to do that?

Valentina Alaasam:
That's a great question. I think it probably varies in different cities. So I would just talk to your local government, whoever is your local legislator or governor maybe. And they'll probably be able to direct you if you talk to that office, direct you to the people who are in charge. Because with streetlights, yeah, it probably depends on the city and what department they have that will regulate that. It's a bit easier to talk to somebody on private land. So if you know that... For example, I'm on a college campus, so I can talk to my university about turning off those lights because they own all of that land, but at the city level, it will take some digging, and it probably just requires getting involved with the local government in some way.

Ashley Peery:
It's probably a good bit of persistence, I'd imagine too.

Valentina Alaasam:
Yeah.

Ashley Peery:
So a comment from Selena. She says, "My streetlight has been out for months. Thank you for changing my mind on calling the city of Reno to fix it. Great presentation."

Valentina Alaasam:
That's great.

Ashley Peery:
So Nick did have a question about how we approach local city government on reducing light pollution, which I think you have already answered a little bit in your previous answer, but he has a follow-up question that says, "Have you measured the increase in light pollution over the years, and how far will it go? Do you think the birds will adapt over time?"

Valentina Alaasam:
That's a great question. So I haven't personally. There is research out there, though, that has monitored the change in lighting over time based on satellite images that we have. And the switch to LEDs was a huge increase. And I think part of it, like I said, is it's mostly because light's becoming more efficient. And so many years ago, lights were expensive, and most developing nations for example, or low-income neighborhoods, just didn't have a lot of lights. But now that it's becoming so efficient, the cost is going way down, and you can use more light without using more energy. And so we're just putting out brighter, more efficient lights. And so there's been a huge increase in global light pollution in the past 40, 50 years. And I think there is some indication that the birds can adjust. So there's a ton of birds that live in our cities, some of them, some species are avoiding cities. They move out; they don't like it. But others are doing great, like house sparrows, pigeons. The ones that you see in your backyard are like, "Fine, this doesn't matter to me."

And so it is kind of interesting, and that's actually something that I'm also studying, is whether birds have the capacity to habituate to this and get used to it like we do. But I think there's always a question of if they can habituate behaviorally and get used to it, like us, does that mean they're not still being affected at a physiological level? So I sleep every night with a huge streetlight outside of my window, and sometimes it wakes me up at night when a car goes by, but sometimes it doesn't. But at the same time, I think it's likely that if I just use curtains, I would probably get a better night's sleep. And it's hard to quantify those subtle effects, where maybe things are adjusting, but over time, if night after night after night, your melatonin's a little bit off, or you're just sleeping a little bit less good, your hormones are shifting a tiny bit, over time, that can lead to consequences.

And it's just kind of hard to know that on a short scale when we're looking at things just in the moment, when we just get a snapshot of, "Are the birds okay?" It's hard to quantify how they're really changing, and whether they might eventually be dealing with some health consequences, but at the same time, they could. I hope that they're adapting. I hope light is one of those things that it's really easy to reduce. One of the easiest things that we can do is just turn off lights, but it's never going to go fully away. So the birds that live with us in our cities, the animals in general, the insects, all the animals that live here are going to have to adjust eventually. And they probably already are. So it's probably a little bit of both, I would say. Yeah.

Ashley Peery:
Thanks.

Valentina Alaasam:
The other one was about how to talk to ...

Ashley Peery:
It was about how to approach local city government. So it's really ... If you want to advocate for reducing light pollution in your own town...

Valentina Alaasam:
Yeah, and so...

Ashley Peery:
... how do you go about this?

Valentina Alaasam:
I'll just add quickly. I mean, I did already say this, but I would emphasize the cost-effectiveness of it because most of the time, we're using more light than we need, and reducing by just half will cut your energy bill by a lot. So it's a cost-effective solution. It usually doesn't take any extra effort. You can change the light bulbs if you want to; they're not that expensive. But you can also make a huge difference by not making any real changes, just turning lights off. And yeah, it'll be a cost and energy-effective strategy. And businesses can advertise that if they want. Like Tucson, being a green city, you can advertise for yourself if you have a lower carbon footprint, lower energy consumption overall, and you'll also be saving money.

Ashley Peery:
Yeah, thanks for those tips. It can be tricky, but I mean, obviously there are some success stories where light pollution's been reduced with positive effects for birds and likely other organisms too.

So the next question is related to the biology of birds that you studied. So the birds you studied have these thin skulls and photoreceptors. What is known about how other birds sense light specifically? Do other birds have a photoreceptor on their heads, like these ones that you studied?

Valentina Alaasam:
Yeah, good question. I wasn't clear about that. And they do. So this is something that I think is universal across all birds, at least birds that fly. But I think all birds kind of evolved similarly, and then some stopped flying eventually. But the reason is because to fly, you need to be lightweight. And so they've evolved these really cool kinds of bones that have air pockets in them. It makes them thinner and kind of transparent. So because of that, they all can photosense straight through their skull. And I think it's the coolest thing. We learned it ... Some research way, way long ago figured it out by basically, like I made a joke about, putting hats on birds, just covering up that part of the skin, or tattooing that part of the skin, something like that. Just covering that up and then realizing they couldn't navigate as well because they couldn't see the stars and know where they were going.

Ashley Peery:
That's kind of crazy to think about.

Valentina Alaasam:
It's so crazy. Yeah.

Ashley Peery:
So another question related to your work. The hormones that you measured, do they oscillate reversibly? If under light, those hormones are elevated, you take the light away, do the hormones stabilize back to normal levels?

Valentina Alaasam:
That's a good question. They are very flexible, so my prediction is that they would go back to normal. We are seeing some longer term effects. So I think it would take a little bit for the birds to readjust, for example. But they are very flexible, and that's kind of the role that hormones play in our bodies. It's our way of being flexible to new environmental conditions. So in the moment, the one that I talked about specifically corticosterone, I said it was involved with stress, but it actually serves a really important function when we're scared or being threatened. So if a bird encounters a house cat, then that hormone, it's kind of like our flight or fight response, that hormone is what gives them this jolt of sugar that lets them just run away as fast as they can and survive. And so they all serve functions, and I think when we're sleep-deprived, we're traveling or whatever, those hormones are up, but it's also helping us stay awake, helping us function.

And it's only when it's chronically elevated for a really long time that we start to worry about how is this affecting us in other ways? Because a lot of things in our bodies are really linked together. And so that's the same thing with melatonin. Sometimes when we're changing time zones, we get jet-lagged, and it's because that melatonin thought it should be going up, and it's not getting the cue to do that. And in the moment, it's okay, but in the long term, I think it can have more consequences than we realize. But they are flexible. So my hope is if we reduce the light in our environment, things will be able to adjust. And we see that in my experiments, like we will expose them to light pollution for a little bit, and then turn it off, and then they sleep fine.

Ashley Peery:
That's good to hear.

Valentina Alaasam:
Yeah.

Ashley Peery:
So that's actually ... We have time for one more question, and we got a submission from Sebastian, who made a comment, which made me think of a question. So Sebastian comments, "We hear birds chirping all night long in Boston," which makes me ask, are birds chirping all night long, is that likely due to light pollution or are there birds who chirp at night?

Valentina Alaasam:
That's a great question. I am not a bird expert by any means. I mean, I am, I guess, technically a bird biologist, but I don't know about all species. So there might be birds with different kinds of behaviors, and some might be naturally more active at night. But I do know that I think light pollution has increased nocturnal activity for a lot of species that don't usually do that. So my guess is that it's a light pollution thing. I can't say 100 percent sure, but that's my guess.

Ashley Peery:
Totally fair. And thank you so, so much for your presentation today. I've learned a lot. I really loved all the animations, the birds with top hats, and thanks for filling in why you put that into your talk. So that is all the time that we have today. Thank you to the audience for all of the questions that you've submitted.
I also want to give a special thanks to everybody who made today's program possible. So that includes our donors, our volunteers, viewers such as you who tuned in today, as well as all of our partners who help us reach, educate, and empower millions of people around the world today and every day. So thank you to all of you. And I need to thank our behind the scenes team. There are folks that you don't see on screen today who do a lot of work to make these webinars possible. Thank you to all of you.

And then next, I have a quick teaser for our next webinar, which is actually going to be on a Tuesday instead of Wednesday, which is our typical day. It's going to be on Tuesday, May 2nd. So coming up in just a couple of weeks, and what's going to feature entomologist, Dr. Sammy Ramsey. He's a super charismatic entomologist. He's studying how mites affect the health of bees, and I hope that I will see all of you at that webinar in just a few weeks.

So lastly, you are going to see a link to a survey. Please take a moment to respond. That should come through to you in the Q and A box, and I think when you close the webinar, it automatically pops up. But if you take some time to fill that out, it helps us to improve all of our webinars, and it helps to ensure that you get the kind of content that interested in seeing in these webinars.

So thank you again to Valentina, and thanks to all of you for tuning in today. I hope to see you all in a couple of weeks.

Valentina Alaasam:
Thanks so much.

Ashley Peery:
Take care.