Dr. Anna Pidgeon with binoculars in tow (photo by forestandwildlifeecology.wisc.edu)
In these episodes, we answer questions like “how and why do birds sing?” and learn how birds adapt their calls and songs adapt to their habitats, and so much more with our bird voices expert, Dr. Anna Pidgeon, a researcher and professor at UW-Madison!
Check out Dr. Anna Pidgeon’s work here!
Subscribe to QuACK on Spotify, iHeart Radio, Apple Podcasts, or your favorite podcast app!
Transcription
Part One
Hey, and welcome to Questions Asked by Curious Kids, or QuACK, a podcast made by Southern Wisconsin Bird Alliance. This is a podcast where we gather questions about nature from kids to be answered with a local expert. My name is Mickenzee. I'm an educator, and I'll be the host for this series. This episode I'll be interviewing Dr. Anna Pidgeon, a researcher and professor at UW Madison, and she'll be answering questions about bird voices.
This episode is going to be in two parts. In part one, we'll get to know Anna and talk about how and why birds communicate. And in the second part, we'll talk more about things like why bird species can sound alike or different, as well as how noise pollution can impact birds. I'm so excited for this one. Let's get started, shall we?
-----
Mickenzee: All right. Hey, Anna, welcome on. Before we get started with the kids' questions, could you tell us a little bit about what you do here at UW Madison?
Anna: Sure. Hi, Mickenzee. I'm so happy to be here. Yeah, what I do at UW Madison, I'm a professor in the Department of Wildlife Ecology, and I teach and I do research, and my teaching is all focused on birds, ornithology, and then a class where people learn to identify birds called Birds of Southern Wisconsin. And my research is mainly focused on birds as well. My research goal, overarching goal is to keep birds common, to learn about their habitat needs and do things that can help people make good decisions when they're thinking about changes to habitat.
Mickenzee: That's so cool. This episode is all about bird voices. And how did you become an expert in bird voices?
Anna: Well, I became broadly interested in birds and other wildlife because I grew up in an area where there was a lot of natural habitat and therefore a lot of birds. And I've had a lot of training from college degree in wildlife management to master's and PhD, all focused on birds. And so along the way, I guess you could say I became an expert in a lot of things about birds.
Mickenzee: Oh, that I love to hear that. Okay, so all of our questions today were submitted by the third graders at Lincoln Elementary School here in Madison. First, this student wants to know how do birds make their songs and how do their bodies work?
Sketch of a bird syrinx (graphic by Carolyn Byers)
Sketch of a human larynx (graphic by Carolyn Byers)
Anna: Yeah, well, birds bodies are different than mammal bodies. And as a matter of fact, from amphibian and reptile bodies as well, in that birds have a special organ, a vocal organ that's called a syrinx. And they also have a larynx, which we humans and other mammals and reptiles have, and which protects our trachea, or some people call it the airway or windpipe from food going down. But then birds at the base of their trachea just before it subdivides, it goes into the lungs. They have this organ called a syrinx. And when air leaves the lungs and the air sacs of birds, it goes across the syrinx and vibrates little membranes called tympanic membranes. And those vibrations are what we hear as bird vocalization songs and calls.
Mickenzee: Whoa, that's so cool. Bird bodies are so different from ours now that we know how they make their songs. This student wants to know why do birds sing?
Cedar Waxwings foraging in a group (photo by USFWS)
Male Yellow-headed Blackbird establishing territory (photo by USFWS)
Anna: Yeah, why do birds sing? Well, birds sing. And more broadly, they make other sounds. They make vocalizations to communicate with other birds or to express themselves, the same reason that we make sounds. Throughout the year, birds make a number of different sounds. For example, when they're foraging for food in the winter, many birds make what are called contact calls that help them stay together in a loose group. And if one of those foraging birds encounters, say, a potential predator like an owl, they may make a different kind of sound, an alarm call. And this notifies the group and then others in the group will also start making alarm calls. In birds that migrate, you often hear those that migrate during the day like geese and swans vocalizing as they're flying along. Cranes, too, are another example. And for birds that migrate at night, which are all of the small perching birds like thrushes and orioles and warblers and sparrows, they make what are called nocturnal flight calls while they're flying through the dark sky. And one more example: baby birds make food begging sounds when they're in the nest, and once they've fledged and they're learning how to find food, they're also still making those food begging sounds. So there are a lot of different sounds that birds make, and most of those that I've just talked about, they're called calls and this is to distinguish them from the sounds they make at the special time of year, when it's time to pair up with a mate and to raise young. And that's what we call the breeding season. And so the sounds that birds make in the breeding season are their songs. And you asked why they sing. Finally, I'm getting around to that. They sing to impress potential mates and to impress potential competitors, maybe to scare potential competitors. And then once they've selected a mate, they continue singing to keep the bond between them strong. So each bird species has particular habitat needs that are best for that species. And a bird works hard to establish a territory in the very best possible habitat for them. And they do this by competing with others, by singing. So the singing communicates things like, I'm a very powerful individual. And if it comes down to it, I can intimidate you out of my territory. And birds also want the very best possible mate in terms of the mate's ability to find food for babies. It's body's ability to ward off diseases, what we call immune function. And by listening to different individuals' songs, birds can hear differences that tell them which is the very best possible mate for them. So differences like how complex is the song or how loud is it? And it's not only the song I should say that conveys this information, but also like the brilliance or intensity of coloration, of feathers, their behaviors, etc. but so they sing to communicate their fitness, how good they are at what they do.
Mickenzee: Wow. Birds are communicating so much.
-----
If you're interested in learning more about bird voices or getting involved with our programs, please head to our website at swibirds.org.
From there you can find free lessons like Bird Call Bingo as well as check out our calendar for events like Birding by Ear. And this is only part one, so be sure to come back and check out part two with Dr. Anna Pidgeon.
If you have a big nature question that you'd like to have answered, please have a grown up or teacher submit your question to info@swibirds.org with the title Questions for QuACK.
Make sure you include your grade and the school that you attend, so I can give you a shout out on the show. And thank you for tuning in and I hope you join us next time on QuACK!
Part 2
Hey, and welcome to Questions Asked by Curious Kids, or QuACK, a podcast made by Southern Wisconsin Bird Alliance. This is a podcast where we gather questions about nature from kids to be answered with a local expert. My name is Mickenzee. I'm an educator, and I'll be the host for this series. This is part two of our Bird Voices episode with Dr. Anna Pidgeon, and she'll be answering questions about why bird species sound alike or different, as well as how noise pollution can impact birds.
And we'll be talking about so much more too. I cannot wait for us to get started. All right, here we go.
-----
Mickenzee: These next questions are about the way birds sound. Why does it seem like small birds have high pitched voices?
Sandhill Cranes calling in unison (photo by Arlene Koziol)
Tundra Swans having a chat (photo by Arlene Koziol)
Anna: Yeah, that's somewhat true, but not completely true. Small birds have a range of sounds. Some are higher and some lower. The amount of musculature or the amount of muscles that surround that special organ called the syrinx is what birds use to control the pitch of their voices. So some have more simple and fewer muscles, and some have more complex and just more muscles. And that gives them the ability to have, greater or a smaller range of sounds that they can make. And another thing that affects how high or low birds’ voices are is how long their trachea or their windpipe is. And in some birds, like swans and cranes, it can get to be really crazy long. And that communicates kind of how big their bodies are, because the longer a trachea, the more resonant or and also the lower the frequency of the sound. So there's a lot of different factors and why a bird might sound the way it does.
Mickenzee: Right. And why. This one's a silly question I like. Why does some days birds sound like they're singing and some days they sound really squeaky?
Anna: I'm really curious about the experience of the person who asked this question. I wonder if they're referring to a pet bird, or how would they know that one bird's voice changes from day to day. So some things that come to mind are that birds, just like people, have a range of sounds that they can make and have recognizable voices. And I wonder if the person was hearing different birds of the same species. Each of which had slightly different voices. Again, just like people have slightly different voices or other things that might cause a bird's voice to perhaps sound squeaky. Maybe if they're dealing with, for example, a virus. The way, humans voices change sometimes when they have a cold that's caused by a virus or sounds can be distorted by things like the wind and bouncing off of buildings. And that may be something that alters the way a certain birds voice sounds from day to day. So those are some ideas that I have about, why a birds voice may sound different from day to day.
Mickenzee: That's really interesting. This last question has a little bit of a story that goes with it. So the third graders noticed that when they were learning about different bird songs, that birds that live in a similar habitat sometimes sound similar, like an osprey and an eagle. And so they wondered, do bird calls adapt to their habitats?
The forest dwelling Hermit Thrush’s songs have pure tones (photo by Andy Reago & Chrissy McClarren)
The grassland dwelling Red-winged Blackbird’s songs have buzzy trills (photo by USFWS)
Anna: That is such a great question. And the answer is absolutely yes. Through evolutionary time, birds' songs have adapted to be most effective in their preferred habitat. And so, for example, songs of birds that require forests to live in have more pure tones, what we might call whistles, and tend to include fewer trills than those that live in open grasslands. And sound transmission experiments have demonstrated that rapid trills get easily blurred in forests by reverberation, so they get distorted. So that's probably why forest bird songs do not contain many trills, but they do contain wispy tones like whistles, especially thrushes. You can think of examples there. And moreover, these pure whistle tones are enhanced by the reverberations off of all the vegetation that's in forests.
Mickenzee: Wow, that is so interesting. I never knew that. Okay, so lastly, the third graders also learned about noise pollution and want to know could buildings in cities like Chicago affect how the bird calls sound or a bird's ability to hear another bird?
White-crowned Sparrow (photo by Kelly Colgan Azar)
Anna: Yes, absolutely. There has been a lot of study of this phenomenon in recent years, and there is substantial evidence that a shift in minimum frequency, or that is how low or high a note is, but that notes increase with increased noise levels, like in urban areas. In other words, higher notes are used in more noisy environments. And there is a great study by Professor Elizabeth Terry Berry, who found that in San Francisco that White-crowned Sparrow song increased in pitch over a 35 year period as the traffic noise level increased over that same time period. And a likely reason is that these higher notes are less likely to be masked by the low frequency noises that are really common in cities, and therefore, the higher notes are more likely to be effective as a communication signal among the birds. And Dr. Terry Berry also tested how this change in song affects the sparrows hearing them, and she did that by presenting males during the breeding season. So when they're on territories and defending against other males with recordings of current songs and historical songs also made in San Francisco 35 years ago. And she found that the males responded much more strongly to the current than to the historical song, suggesting that the current songs communicate more effectively in the current urban environment.
Mickenzee: Whoa. I've always been fascinated by bird song, but I didn't know that there was just so many interesting things to learn. Thank you to the third graders at Lincoln Elementary for submitting these questions. And thank you, Anna, for coming to teach us all about it.
Anna: Oh, thanks so much for your interest. And I really enjoyed talking about birds.
-----
If you are interested in learning more about bird voices or getting involved with our programs, please head to our website at swibirds.org. From there you can find free lessons like Bird Call Bingo as well as check out our calendar for events like Birding by Ear. If you have a big nature question that you'd like to have answered, please have a grown up or teacher submit your question to info@swibirds.org with the title Questions for QuACK.
Make sure you include your grade in the school that you attend, so I can give you a shout out on the show. Thanks for tuning in and I hope you join us next time on QuACK.
Check out SoWBA’s free lessons, games, and activities!
Get out and explore nature with us!
Make a donation to Southern Wisconsin Bird Alliance
Audio Editing and Transcription by Mickenzee Okon
Logo design by Carolyn Byers and Kaitlin Svabek
Music: “The Forest and the Trees” by Kevin MacLeod
