transcript

Speaker 1:
[00:04] Hey, and welcome to the podcast. I'm Josh, and there's Chuck, and Jerry's here too. And this is a Short Stuff, which is why I realized now that I started this off incorrectly. Short Stuff, let's go.

Speaker 2:
[00:14] That's right. Big thanks to Britannica, Yellowstone Wild Tours, California Department of Fish, Wildlife, New Hampshire Audubon, and Audubon for information about the ground headed, brown, ground?

Speaker 1:
[00:25] Yeah.

Speaker 2:
[00:25] Brown headed cowbird.

Speaker 1:
[00:26] Thanks to you, me too. She brought this bird to my attention.

Speaker 2:
[00:29] Oh, I forgot, youme.org.

Speaker 1:
[00:33] Chuck, we're talking today about cowbirds, and really in particular the brown headed cowbird. You ever heard of them before?

Speaker 2:
[00:39] Had never heard of them.

Speaker 1:
[00:40] I hadn't either. But if you want to know about a brown headed cowbird, the first thing you need to know about it is that it's a brood parasite. What does that mean, Chuck? What does that mean?

Speaker 2:
[00:52] Well, I had never heard of this trait in a bird either. A brood parasite is a bird that will be like, you know what, I don't want to build my own nest and go through all that whole process of raising these babies that I egg out of my body. I'm just going to go lay those eggs in some other bird's nest and then go away and shirk parenthood.

Speaker 1:
[01:13] Yeah. You do it for me. How about that? Yeah. That's exactly what they do. You're like, why would you do that? You have to be a jerk bird. Yeah, I think a lot of people think of cowbirds as kind of jerk birds just for doing that. But from their point of view, this is just an adaptation that made a lot of sense to how they evolved originally. They're from North America and they were, I think, indigenous to the Great Plains of North America. The reason why is because there's another animal that was indigenous to the Great Plains of North America. They had a commensal.

Speaker 2:
[01:52] Is it commensal?

Speaker 1:
[01:54] I don't know. I don't think so. I feel like there's a U in there. Anyway, they had the kind of relationship where they benefited but didn't harm the other animal. I feel like it's high time we tell everybody what the other animal was, Chuck.

Speaker 2:
[02:07] That's right. Drum roll, everybody. It is the bison. They would follow these bison across the plains. Sometimes they were, initially, they were called bison birds or maybe buffalo birds, even though that's wrong. They would follow these guys across the plains and they would feed on the insects that the bison would kick up and they would sometimes ride along on their backs. And this is, this led to why they would not birth their own little eggs in their own little nest and raise them because they went where the bison went and they were always on the move and bison can travel, buddy. So if they're moving 10, 20 miles a day and they're catching a ride on a bison's back or at the very least flying around with a bison, they're not staying there long enough to set up their own home.

Speaker 1:
[02:52] Yeah, Cowbird was rolling stone.

Speaker 2:
[02:55] That's right. Well, bison bird at the time, I guess.

Speaker 1:
[02:57] Oh yeah, that's right. So yeah, it totally made sense that like they still need to reproduce. So they would just find a nest somewhere along the bison route and leave their egg and then fly back to the bison and be like, wait, wait, wait for me, everybody. And I feel like that's a pretty good place to take our break. What do you think?

Speaker 2:
[03:18] I totally agree.

Speaker 1:
[03:20] All right. We're taking our break, everybody. So Chuck, sadly, as probably most people know, the American bison was overhunted almost to extinction. We can seriously, legitimately thank Ted Turner for almost single-handedly bringing the American bison back.

Speaker 2:
[04:01] That's right.

Speaker 1:
[04:02] And so while in between that period, between overhunting and Ted Turner, the bison bird was like, I don't have my niche anymore. I need to figure out what's going on here. I gotta start looking elsewhere. They basically spread outside of their ecological niche in the Great Plains to look for other things they could do to replace their bison friends, which they must have just been horrified by all the massacres they witnessed.

Speaker 2:
[04:30] Yeah, I bet, probably very sad times for the bison bird, but eventually one of them would land on a cow and say, hey, these guys aren't so bad to ride around on. But here's the thing, is cows don't move around like the bison did. They're not traveling 20 miles a day. So you might think, all right, they're leading a more sedentary life, these birds are now cow birds. And so maybe they will change their behavior now that they don't need to do this. But they didn't. They said, we love these cows, but we also like this adaptation because who really wants to parent their young?

Speaker 1:
[05:08] Yeah, exactly. We're not going to change anything. We're just going to stop wasting so much effort flying around all the time. I think there's, I don't remember, there's five species of cow birds, at least the parasitic versions. And the brown-headed cow bird, the reason we're talking about the brown-headed is because it is by far the least picky about what nest it lays its eggs in. So these are, they're not large eggs, they're much smaller than a chicken's egg, but they're probably not as tiny as say a robin's egg. They're middling size eggs. Brown-headed cow birds will lay their eggs in a duck's nest. So this little egg is five times smaller than the other eggs around it. Obviously, the ducks are like, what is this crud? And there are other bird species too that are onto them. But a lot of times the birds will just play along or else just be fooled.

Speaker 2:
[06:07] Yeah, I think the finch is notorious for not liking these eggs in their nest. They're not good hosts to these intruding eggs. So apparently, they will die if they are left in charge of a finch. Other birds will get mad and puncture holes in the eggs or just beak them out of their nests. I think the cat birds do that. And then the yellow warbler has a strategy where they build nests. They'll just nest a new nest on top of those poor little eggs. Sometimes several new nests, like up to five new nests on top to really bury those guys.

Speaker 1:
[06:45] I know. There's some like Tom and Jerry-like scene that makes me think of. But like it happens like really, really fast.

Speaker 2:
[06:54] Right, right.

Speaker 1:
[06:55] So if, however, the cow bird happens to lay their egg in a nest that the bird is like just too lazy to do anything about, that cow bird is probably going to be the only hatchling that survives. Because it has adaptations to outcompete other birds in the nest that it's laid in.

Speaker 2:
[07:19] Yeah. One of them is they have a shorter incubation period. So they're born first. I think sometimes up to three or four days before the other eggs might hatch. And so they got a little bit of a head start where they might take care of those extra eggs themselves. These baby birds might nudge those things out. So earlier you were saying there were some bird enthusiasts that kind of think these are jerk birds. And in my mind I was like, yeah, but you know, like these birds are doing their thing. Like you can't get mad at nature for being nature, but then you get to this part and you're kind of like, oh man, that really kind of sucks.

Speaker 1:
[07:53] Yeah, yeah. So even if they're like, I'll let you guys stay. And the cow bird doesn't push the other hatchlings out. Just from being a couple of days older, they'll be able to muscle the other birds out of the way to get the food and they'll just continue to outpace them in their growth. And it might be so bad that the other hatchlings starve because the cow bird doesn't let them get any of the food from the mother.

Speaker 2:
[08:18] Yeah, so I get it now, bird enthusiast. I have a question for you though, Joshua, which is with all this going on, not being raised by their parents, how in the world does the cow bird not start to take on traits of the bird that raised them? How do they remain cow birds?

Speaker 1:
[08:37] I'm glad you asked that. We don't really know, Chuck, as a matter of fact. There seems to be some sort of mechanism that prevents cow birds from imprinting onto their adopted or foster parent from the other species. They're not exactly sure how this happens, but they think that cow birds, hatchlings, are attuned to the sound of adult cow birds in the area and that they're naturally attracted to it. Once they learn to fly, they'll go seek out other cow birds. And I guess there they learn all of the cow bird habits like playing craps and smoking cigarettes and all that stuff. And then also they do some weird nighttime excursions out of the nest while they're being raised. And I guess no one knows where they go, but that's something that they're like, that probably has something to go learn actual cow bird behavior too.

Speaker 2:
[09:33] Yeah, I wonder if when they are attuned to the sound of their own, if they eventually fly out when they're big enough to find them, if they're like, mama? And the birds are like, don't look at me, buddy.

Speaker 1:
[09:44] Right, exactly. Even if it was their mom, they wouldn't take credit because it's a brown-headed cow bird.

Speaker 2:
[09:50] Yeah, that's right.

Speaker 1:
[09:51] So if you want to find one of these, you might see them in your feeder. They are adapted to all over North America, rural, suburban, urban. You can find them everywhere. They're a smallish, a medium-sized, smallish bird, whatever that means. But the males have a brown head that shines and shimmers almost like a deep red in the sunlight. They also have iridescent greenish blue plumage on their body. The females, you're not going to really notice that much. They're much less showy, but that's pretty standard for birds anyway.

Speaker 2:
[10:28] For sure. I think Short Stuff is about out, but since we have an extra 30 seconds, I'm going to take this opportunity to promote the new Nature series from the BBC, the latest in their ongoing work with the great David Attenborough, Sir David Attenborough, Asia.

Speaker 1:
[10:48] Oh, nice.

Speaker 2:
[10:50] It is fantastic stuff as always, exactly what you would expect out of the BBC Nature series. Sir Attenborough is 99 years old. He's going to be 100 in May, and he's still doing it. And it's just some really amazing, striking stuff.

Speaker 1:
[11:08] Did they spell it like Steely Dan?

Speaker 2:
[11:12] Spell what like Steely Dan? Oh, no, no, no, no.

Speaker 1:
[11:15] No, they spelled it normally?

Speaker 2:
[11:16] A-S-I-A.

Speaker 1:
[11:17] Okay, gotcha.

Speaker 2:
[11:17] Not A-J-A.

Speaker 1:
[11:19] Well, there you go. You're welcome, BBC. Chuck just hooked you guys up with some viewers. I'm going to go check that out myself.

Speaker 2:
[11:26] It's great. You guys would love it.

Speaker 1:
[11:27] Cool. Well, then I think now Chuck Short Stuff is out.

Speaker 3:
[11:34] Stuff You Should Know is a production of IHeartRadio. For more podcasts, MyHeartRadio, visit the IHeartRadio app, Apple podcasts, or wherever you listen to your favorite shows.