106 - Why Do Birds Sing at Dawn?

0:00Why is Don such a big deal to the animals and birds out there? That's what we're going to talk about today. Hi, this is Jill from the North Woods talking about nature right outside our front door. Just imagine maybe your backyard or maybe the local marsh that's close to your house and pick a specific morning just before sunrise. Or maybe even in the North Woods, April, early May, and it's still just a little bit dark. It's still just the hinges of coldness overnight. You still feel the coldness, the dampness. There's a single sliver of light on the horizon and guess what? The birds start singing. It's one bird and then another joint in and another joint in it within 20 minutes. The trees, the shrubs, the skies around you are erupting in sound. It's layering over each other and it's such a beautiful sound. I get to hear this.

1:00I'm not a morning person, so the really the time I hear this is when I go camping. I mentioned before that when I went camping, there was this one, it was quiet at night. The birds go to sleep. They don't want to get picked off in the middle of the night, so they quiet down after sunset. Boy, there was this one bird and he chirped basically all the way up to midnight and then all of a sudden I woke up. I don't know, somewhere like I said around 5 o'clock in the morning and had to go to the bathroom. I got off my tent and I walked over to the bathroom. That bird picked up right there again. He was single bird and then suddenly he was joined by the Cardinal, joined by the Robin. When I hear Don Corris, it's usually because I'm camping and it is amazing. Once you've heard it and you've really, really heard it, it will stun you. You'll never take a quiet morning for granted again. The thing about the Don Corris is, it isn't random. Every single thing that happens about the Don Corris, when it starts, who goes first,

2:03how long it lasts, why it happens that Don specifically has reasons to that and that's what we're going to talk about. The first part of it is that what is the Don Corris? It's a surge of birds' song, roughly 30 to 90 minutes, around sunrise, peeking somewhere in the spring, where birds are trying to establish their territory. You see Redwood and Blackbirds trying to claim their area, but also trying to find a mate. The men birds that sing are trying to attract their babe and it happens year round to some extent, but it's not so much in winter and in my neck of the woods, but in other places of the world. It's year round, but in spring, it's a lot of us. It's the most complex and it's the most of the species are participating in it. It's not unique to any place. I live here in the North Woods, but you might live somewhere else. You too will have a Don Corris if the season is right and maybe if you don't have harsh

3:04winters, maybe it is all year long, but it happens on every continent where there are birds. This will be the same phenomenon and it is the same reasons everywhere in the world. I can say where I live, it's usually somewhere between late April through June and birds will sing in the morning because they do sing more, but the Don Corris where it really kicks in is going to be during that particular peak. That's going to be the peak of it. The morning that most species are simultaneously singing tends to be, for me, more like mid-May. It may be different for you, but when the spring migrants have arrived, and for me, they usually arrive for the most part by mid-May. That's usually where it's at. When the spring migrants have arrived, they might not have quite settled in, gotten into their nesting routine. There is actually an international Don Corris Day that is held on the first Sunday of May,

4:09so people around the world try to go out specifically on that day and listen. It started in Birmingham, England in the 1980s and now has spread out globally. Like I said, mine comes a little bit later than that. England is a little bit more temperate than where I live, but it's a good chance that you'll get it here during the timeframe, all the birds singing. Why a Don? The heart of this is that the birds are singing specifically the loudest at Don, and there's a couple of reasons for it, is that first of all, the light is still too dim to forage, so they don't have anything else to do because it's still too low. The insects aren't active yet, the insects are not warm-blooded creatures, so they are low activity when it's kind of colder in the morning. It's too dark to hunt, it's too cold to hunt, and so instead of wasting energy for an activity that's not at its best, they start communicating. The singing does cost energy, but it costs a lot less energy than foraging around in the

5:12dark. Don is essentially a dead time for feeding, so the birds fill it with social tasks that they're establishing who they are, where they're standing, and what kind of babe they're looking for, and that's what they're doing. Sound also travels farther and clearer at Don. One of the most remarkable things about this is that early Don, the sun heats up the ground and the atmosphere layers a little bit differently than it does during the day, so the sound waves actually travel a little bit farther along the ground level than it would at other times during the day, and so that means that the song, being sung at Don, can carry maybe two to three times farther than maybe if you're saying that same song at noon. The birds singing at Don broadcasts to a much larger audience, and that's really quite amazing about it. The hornones also peak for birds at Don in spring, the male songbirds experience a surge of

6:14testosterone, driven by which is hormone driven, and that is triggered by the increasingly longer days, so the longer these days come in, suddenly the birds in their home runs kick off as part of their breeding season, and that makes them more aggressively singing in the morning time about their territory and about finding a mate. And right at Don, that's when they're hitting their peak hormone levels, and the urgency is a little bit stronger at that point. And if you think about the Don chorus as almost like a neighborhood roll call, every male in the area is announcing the territory. I'm right here, made it through the night, territory still mine, and a male who goes silent in the morning is signaling maybe illness, weakness, and a rival might even notice that. A potential mate will not come because they don't hear the song coming through, showing

7:17up singing loudly in the morning is like leaving your card, right? I'm here, this is my place, come meet me for drinks, you know, that kind of thing. It's a signal of fitness. Now I can tell you that my bird is having some health struggles right now, and he stops singing. And he is not at this point, he would start singing at this point, he is not singing. And so I think if a bird is not feeling well enough to sing, it means that they're not well enough to attract a mate either. And it's a signal, right? It is definitely a signal. So then comes the other interesting question about what is the order of the birds? Is it random? Does this one bird kick it off? And different species don't join in at a very specific predictable time related to sunrise. And they call this sequence, the sequence of onset. And it is consistent enough that you could actually, I don't say tell time, but you can

8:18see how the morning is progressing by listening to which birds are actually singing. So the early singers, the ones who go first tend to be the birds with the largest eyes relative to their head, that gives them more light. The birds can see well enough to function, remember I mentioned before, that once you start singing, it is putting your credit card, business card down saying this is my area, I'm here, but it also means that if you were a predator, the predators see better and lower light. And if you can't see that predator coming at you, you won't be able to get away. It makes a bird vulnerable at that point. So what you'll see is that robins are very famously early singers, often starting about 30 to 40 minutes before sunrise, toes, wood thrushes, oven birds, early risers too. And so when you start hearing the robins sing in the dark, you know it's about to open this whole dawn of chorus coming up in the morning.

9:21In fact, in my backyard, sometimes when I'm trying to sleep, in winter time, I can't really tell what time it is unless the light has come up, but sometimes it is pitch black out there. And I will hear the robins go and then I'll hear the cardinals go. And then it's a signal like, uh, you really got it like, you know, this much time left on your, on your alarm system. So I know it's coming soon. The middle layers are often like more like the song sparrows, yellow warblers, these are going to be the smaller birds, common yellow throws, red wing black birds. And that means that they add to this kind of complex of sound. There's a real light in the sky at this particular place. And it is so chock full of birds. What's amazing about it, and I'll talk about this in another show sometime, is the Atmerlin, where you can let it run, and it can hear the birds singing when you have a course of birds singing. To me, it is tripped, tripped, tripped, you know, it's very hard to hear unless you really

10:25know that bird well, what is singing in any given moment. It is a cacophony, a mishmash of all sorts of birds singing. Maulen is able to tease it out. I mean, that's kind of the most amazing thing about it. And then the late joiners tend to be like the house burrows, the house runs, more of the suburban species that come in. And they wait until they're comfortable before they start singing. So when this means to all of us who go out there in the dark, we, when we hear only one or two voices, you're going to kind of catch the very opening notes of the chorus. But you give it 20 minutes and you'll start to hear it build and build, and then more and more birds jump in. Like I said, if you're looking at some early and late singers, you'll start noticing, but by the time this is going full blown singing, you're going to have the robins, the thrushes, the sparrows, the toes, the redwing blackbirds, all the thrushes that are out there, I said thrushes, the warblers, the common yellow thrushes, warblers, Baltimore orals, scarlet

11:26handagers, they are all going to start kicking in and they're going to start singing at the same time. Viri, that's the one that was singing very late into the night when it was camping and was one of the ones that was singing. But essentially it's going to start coming in and it gets pretty amazing. When you add on to this Don Corus, the females are out there listening, they're evaluating. The male singer who sings earlier, longer, louder, maybe with more complexity. Every once in a while you'll hear, you know, maybe I think of Cardinals, you know, where it gives its call. And then all of a sudden there's like made up notes at the end and you're like, that's not really part of a cardinal song when they add that complexity, that little extra something in their song, it's advertising. Not only can I sing my bird song to you, I'm super fit. I could even make up some additional song after that. So that Don singing requires the bird, like I said, to have survived the night, being

12:27good condition, be healthy enough, have enough energy reserves on them so that they can sing a song before eating breakfast. So it is a sign of health for that bird and the females are out there listening and like I said, they're listening for that loud, early voice and maybe even a little complexity in it too. It costs real resources for a bird to do anything before they have had a chance to eat. So the females are paying attention and the males who sing, like I said, better, whole better territory, they father more offspring. And so it's not just about, you know, creating this cacophony, this Don Corus, it's about putting your presence out there, attracting the female sing. I'm super healthy and I'm well fed too. So in those spaces, that's where those pair bonds are maintained. And the Don Corus, like I said, isn't a one-sided broadcast because the other side is listening

13:28to it and saying, okay, there's my mate right there. So one thing to mention that when we look at the Don Corus in the broader sense of things, it was also more than just the birds. If you get my neck of the woods, you might start hearing spring peepers, wood frogs in nearby wetlands. That's why I said marshes are almost even a little bit better. I hear them in my backyard, but I don't have peepers and frogs in my backyard. Well, you'd have frogs in my backyard, but not these particular frogs. And then you might hear the frogs join in on this noise. Then the woodpeckers will be drumming on the tree. They do that not only to catch bugs, which we know that they drum on the trees to get the bugs out, they're also drumming again for territorial purposes. So that the other woodpeckers know, I'm on this tree, this area is mine. And then they also drum on the tree so that it makes the insects active. And then the birds are able to pick those insects out.

14:30So again, the woodpeckers that are the loudest, that are doing the most drumming in the morning, they're also drumming up their breakfast as well. It's really great to get out there and start listening to this full texture of sounds coming right, like I said, just before sunrise and then afterwards. And then the warmth of the air comes in. I know when I go bird watching early, at some point the birds are very, like I said, way up in the canopy. And then when the sun starts to come in a little bit more, the dawn chorus comes down and you start seeing bugs flying around. And then that's when the birds come out, the birds come out of the trees and start eating all the bugs. And then the chorus dies down a little bit, fades a little bit, and the birds take off and disperse to try to feed. That's why bird watching the morning is such a worthwhile endeavor. So I hope that gives you a chance, maybe, you know, to set an alarm sometime this spring go aside 30 minutes before sunrise.

15:31And you don't even have to know what the birds are, although you can get the Merlin app on your phone and find out what the birds are, but just listen to it. Just hear how many different voices you hear out there. It's just, like I said, if you get out there into a place where there's a lot of different kinds of birds, maybe a marshland, it's one of those sounds that you'll never forget. One thing to note about the Robin is that Robbins, when you have them nearby, pay attention, like I said, when they start singing, like I said, they're almost always the early bird. And that single bird kind of kicks off a nighttime of quiet. And I, like I said, that's something I noticed when I'm sitting in bed, I can hear the Robbins in my backyard. I think these bird songs are just beautiful. You might take note about the International Dawn Chorus Day. Like I said, the first Sunday in May, you can put it on your calendar. You know, like I said, but you might want to adjust. For me, it's in there, you know, but it's a little bit later for me.

16:35Again, if you're looking for another book, I'm going to give you another Burt Heintra book called, Trees in My Forest. And he talks a little bit about the soundscape in the early morning in the forest setting and his experiences with it. His writings, like I said, they're so tuned into the observation of nature with a little light science in there. It's a really great companion to this particular episode. You can also find out why Bird Sing by David Rothenberg. It's another really good book. It uncovers this exploration of birds and its music. So I appreciate you being out there. Remember that you can always email me at jillestartwithsmallsteps.com. I hope you're having a great day. I hope you're getting out there and listening to nature outside your front door. Like I said, in my backyard, it's not even outside my front door. It's out my bedroom window. But I hope you're enjoying it. Leave a comment if you're watching this on video. It's also a podcast. You can email me at jillestartwithsmallsteps.com. Thanks so much for being out there.

17:36And I hope you come back. I hope you're having a great day. I hope you're having a great day. Thank you.