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Transcribed using AI. May contain errors.

Amy Quinton If you like listening to Unfold, please subscribe and follow us on your device. That way you'll never miss an episode. You can do this on Apple, Spotify, or wherever you get your podcasts. Go ahead, make your listening easier. 

Amy Quinton: Listen closely. Kat. 

Kat Kerlin You're playing me something again. Is this like that episode I co-hosted when you played the whale sounds? 

Amy Quinton Yeah, But this time it's a tiny sound from a tiny bird. 

(Phoebe sound)

Kat Kerlin What bird is that?

Amy Quinton That's a black phoebe. 

Kat Kerlin Those are like tiny black songbirds, right? They only grow about six inches tall. Maybe they're flycatchers or flying insect eaters. 

Amy Quinton Yeah. I first learned about black phoebes when I started observing one in our backyard in Sacramento. It perched right in front of me on a lower tree branch. Didn't know what kind of bird it was so I looked it up and it still comes by occasionally. It's really cute.

Kat Kerlin Well, they live all over cities, backyards, urban parks, sometimes under bridges. It seems like they're everywhere, if you look closely enough. 

Amy Quinton Well, three UC Davis researchers are studying how phoebes are responding to increased urbanization and environmental change. It's a research project aptly named Project Phoebe. 

Kat Kerlin Little bird. You'd think it'd be difficult for them in the big city? 

Amy Quinton Well, they do face a lot of challenges, but they're also pretty resilient. And ecology. PhD student Sage Madden, the project lead, wants to find out just how these phoebes are coping. 

Sage Madden Our world is becoming increasingly urbanized. So, larger and larger proportions of habitat for birds are in cities. And actually cities can be spots where we can conserve species, including rare and endangered ones, if we know how. And so I think learning how to make our cities friendlier to birds, and what strategies birds can use to cope with them, is going to be really important as we continue to urbanize. 

Kat Kerlin Birds also make people happy. That's important too. Science shows that people who listen to birds have a better sense of well-being. 

Amy Quinton True, but these little phoebes have a tough future in the big city. Different types and numbers of predators, for example, potentially more or higher concentrations of chemical pollutants. 

Kat Kerlin Don't forget hotter temperatures from climate change causing cities to become heat islands. 

Amy Quinton So in this episode of Unfold, we're going to find out more about just how these little phoebes are adapting to the big city compared to a more natural habitat. 

Kat Kerlin Are we telling this episode Little bird. Big city? 

Amy Quinton Sounds perfect. Coming to you from UC Davis. This is Unfold. I'm Amy Quinton. 

Kat Kerlin And I'm Kat Kerlin. So let me guess, Amy, did you go birdwatching? 

Amy Quinton I did, and I look for birds in a lot of places where you wouldn't think to look for a bird. But we start our adventure in a city park. I'm with Sage and Jacob Johnson, who's also a researcher with Project Phoebe. 

Jacob Johnson We are at Chestnut Park, a very quiet little park in the middle of Davis. 

Amy Quinton And we're next to a tennis court, a children's play structure and what looks like a small beige maintenance building. 

Jacob Johnson And in the eaves of this building, there is a mud cup nest that two birds, two black phoebes, have painstakingly constructed over weeks and weeks of effort out of mud. 

Kat Kerlin They make their nests out of mud. That must take forever. 

Amy Quinton Exactly. Jacob and Sage have watched this mud nest all year, and know that these two phoebes have already had chicks, but they'll have more. Sage says right now they're renovating. 

Sage Madden They line these mud cup nests with grass, and they'll pull out the old dirty grass and then put a fresh lining in for their new chicks. Otherwise, they reuse the same mud cup because it is an immense amount of work to build. It's like thousands of individual globs of mud that the parents like, deliver and put on the wall. 

Kat Kerlin So it's like they're renovating their nursery, getting ready for new chicks. Cute, but a maintenance building? That's a strange place for a nest. 

Amy Quinton Sage says buildings provide just what they need for their mud nests: shelter. 

Sage Madden They need a really specific geometry, where they need a vertical wall that has some sort of overhang covering it. And that's hard to find in the natural world, but pretty abundant in cities. So they seem to be moving into our cities and expanding their range in this way. 

Amy Quinton In their natural habitat, they'd look for cliff rocks with large overhangs or protected pockets and old trees or even caves. 

Kat Kerlin And they'd obviously need a river or creek to make mud. 

Amy Quinton Right? So Sage and Jacob are at this particular nest to observe the bird's behavior, and to compare how the birds behave in an urban environment versus a more natural environment. 

Kat Kerlin So what kind of behavior do they look for?

Amy Quinton Well, what do songbirds do Kat? 

Kat Kerlin Well, they sing and they fly. They mate. They eat. They poop. What else? 

Amy Quinton Well, all of that is true. But a bird song is very important. Jacob says they sing for two reasons. One, to attract a mate and two to defend their territory. 

Jacob Johnson Birds will go around their territory and they will sing at different spots. And that will mean, "This is mine. This is where I live." And so a big no-no in the bird world is singing in another bird's territory. This causes the birds typically living in that territory to see a challenge. 

Amy Quinton So in order to observe these birds behaviors in the big city, Jacob is going to challenge them. 

Kat Kerlin How? 

Amy Quinton By playing another Phoebe call from a recording. Jacob, who is getting his PhD in animal behavior, wants to find out how these phoebes respond when trying to defend what's theirs. Jacob lays down a small speaker on the ground next to a jungle gym. It's several feet away from the bird's nest, but he cleverly disguises it under some leaves. 

Sage Madden Are you covering your speaker? 

Jacob Johnson Yeah. They'll never know. They'll never know. It's so disguised. But this will be our arena. This will be how we see how intensely the birds respond. 

Amy Quinton He stands about 50ft away from the speaker and is looking at the nest through binoculars. 

Jacob Johnson I'll be using playback file one starting in three, two, one. 

Amy Quinton The recording starts and within seconds the female bird responds. 

Sage Madden Mom has gotten out of her nest and she's calling right now from the top of the building. 

Amy Quinton And then something happens. Jacob's never seen before. 

Jacob Johnson Song. Song. Was that mom singing? 

Sage Madden Yeah, that was the female singing. Oh, it's really rare. 

Jacob Johnson Oh my goodness. And here comes the male. Flight two two. 

Amy Quinton The male flies toward the sound to a nearby tree. Then he begins to sing.

Jacob Johnson Song. Song. 

Amy Quinton The pair take turns flying to different perches, from trees to the top of the jungle gym to a park bench. For three minutes, they look for the other phoebe intruder. Then the playback stops. Jacob is amazed by the female singing. It's not unheard of for a female to sing, but very rare. 

Jacob Johnson Not nearly enough research has been done on it because there's, in the olden days, been this assumption that, oh, it's going to be the males that are the aggressive ones, the ones that defend, but the females also defend their territories and they also can sing, which is so cool that we saw that in this, in this individual right now. 

Amy Quinton He says these playbacks are a way to observe the birds aggressiveness in defending their territory. 

Jacob Johnson My guess at the start of this was that, resources in cities, you know, in more urbanized places are going to be more limited for these birds. So I was expecting to see birds have higher aggression. You know, adapt to the city in a way by becoming more territorial, fight for the territory they can hold on to. 

Amy Quinton But he says that's not what he's observed so far. 

Jacob Johnson I've actually seen the opposite. The birds that live in more naturalized places seem to be responding more strongly to play back. 

Amy Quinton We then head out of the city into farmland and pull up next to an irrigation canals, where water is flowing fast. We've come here to visit another Phoebe nest. But first Jacob notices a Phoebe making a racket on utility wire above us. 

Jacob Johnson So did you see that? That male was singing and he just chased another. What I think is another male off of his territory. Did you hear that sharp little peep call he made? Yeah, yeah, that was, territorial aggression in action right there. 

Amy Quinton Jacob won't be playing a Phoebe recording here, but the little bird is clearly demonstrating that this is his territory. 

Jacob Johnson He's fired up. So this male is giving kind of a repeated bout, you know, doo doo doo doo doo doo doo doo. When they get really incensed. Yeah, they can sing louder or they will sing kind of more rapidly. 

Amy Quinton Jacob says he's hoping to determine how their aggressiveness in different environments, whether urban or natural, could affect their ability to reproduce. 

Jacob Johnson I think the most prominent, most impactful, most important challenge of the 21st century is reconciling the needs of our human communities with the needs of the wildlife around us. The challenge of preserving wildlife in this century is, is, to me, the most important and one of the most important things we can think about. 

Kat Kerlin That's so interesting that Jacob is finding that these black phoebes are more aggressive at defending their territory in more natural environments, rather than in the city. Yeah, we mentioned other challenges phoebes face, including chemical pollution. If these phoebes are making their nest out of mud, then they could be exposed to soil and water pollution. 

Amy Quinton And air pollution is everywhere. 

Kat Kerlin So what is the Project Phoebe team finding? 

Amy Quinton That's the n