The Science of Birds - Random Bird Thursday: A Naughty Yet Agreeable Seabird

Episode Date: July 18, 2025

This is the first ever Random Bird Thursday! Ivan is experimenting with publishing these shorter, unscripted episodes. In each Random Bird Thursday episode, the idea is to highlight a bird species that probably isn't going to get featured in a full-length podcast episode. These are birds we might overlook, even though they deserve some appreciation and attention. Random Bird Thursday episodes will be in addition to the normal, long-form episodes. Enjoy, and let Ivan know what you think!Links of InterestCourtship Rituals [VIDEO]SPOILER: The randomly selected species today is the Brown Noddy (Anous stolidus)Support the show

Hello and welcome. This is the Science of Birds. I am your host, Ivan Philipson. The Science of Birds podcast is a lighthearted exploration of bird biology for lifelong learners. And hey, guess what? It's Random Bird Thursday. In this short, mostly unscripted episode, I'll be spotlighting a bird species that probably won't get featured in a full-length episode. With over 11,000 bird species in the world, random bird Thursday is our chance to celebrate one, one of those species, that we might otherwise overlook.

This is a new type of podcast episode, short and sweet, and I'm doing this. as an experiment, I'll run this, or I'll do these for maybe a few months and see how it goes. Probably not every Thursday, maybe every other Thursday, something like that. But it's an opportunity to put out more episodes, but, you know, have some of these shorter episodes that are easier for me to put out, easier for me to produce. So which bird gets the honor of being the first for our first random bird Thursday? Well, we have to push the random bird selector button to find out. So here we go.

Let's push the button. And hey, would you look at that? We got the brown naughty, anus stolidus. The brown naughty anis stolidus. Now, before you start laughing and snickering, I'm not saying anus or anus. I guess I am saying anus. A-N-O-U-S, but it doesn't have anything to do with anus. We'll talk about the meaning of that of the name in just a moment.

And I'm saying brown noddy, N-O-D-D-Y, not naughty. It's not a naughty bird. I mean, it probably is, but that's not the actual name. It's Brown N-O-D-D-Y. Now, before we dive in, I just want to mention a couple ways that you can support the work that I'm doing here on the Science of Birds. First off, you can become a supporter as a member of my Patreon. community. Your monthly contribution as a member provides me with financial support and you get some

perks as a member. So if you're interested in that, go ahead and check it out at patreon.com slash science of birds. Also, I've got an online store called Bird Merch. You can get yourself some cool shirts and support the show at the same time. So just go to birdmerch.com to check out the bird and birding shirts that I, Ivan Philipson, have personally designed by hand. Again, that's birdmerch.com. Okay, the brown knotty. This is a seabird, and it's shaped more or less like a turn, if you can picture a turn. And that's not surprising because noddies are actually closely related to turns. They're in the same family. We'll talk about that in a moment. But this is basically an elegant looking bird. The body is sleek and streamlined. It's

about 15 to 18 inches long or 38 to 45 centimeters beak to tail. The wings are relatively short and broad for a seabird. The wingspan is 30 to 34 inches, which is 75 to 86 centimeters long. These birds have a long, pointy bill. It's black and it kind of curves downward slightly. At the other end, the tail is long and wedge shaped. And when the tail feathers are spread out, the overall shape is kind of rounded when it's fanned out. So, given the name, it shouldn't surprise you that this bird is overall a brown color, kind of a chocolate brown, and that is supposed to separate it from its close relative the black knotty, but the black knotty is kind of just more darker brown, honestly.

It's not really black, black. In any case, the brown knotty has a pale cap. So from the forehead, just in front of the eyes, the feathers are pale gray or even white. And then as you move backwards towards the nape, that becomes darker and darker. So it kind of grades into the rest of the chocolate brown body. It's a very creamy, smooth look. It's very pretty. So that gray crown and forehead really stands out.

Another conspicuous feature of this bird is the eye ring. So it has a white eye ring, but it's not a completely. circle around the eye. It's broken. So there's just kind of this, these white markings around the eye that are again very distinct and quite pretty looking. So what do these birds sound like? Well, they make quite a few different vocalizations, maybe nine different vocalizations or so that ornithologists have recognized. But this is a seabird. It doesn't have a melodic voice. It makes kind of harsh guttural sounds for the most part. Low frequency sounds. Some describe them as making crow-like sounds, like a caw.

But they do make some whistles and clicks and different things. So here I will play you some vocalizations of brown naughties on an island in Hawaii. One of the key things about the way that Brown Notties live and their behavior is that these are highly gregarious birds. They're social. They travel together, roost together, nest in colonies. And like so many other animals and birds, this is considered something that is good for safety. It gives them collective vigilance and safety in numbers, all of that. And it also may help them to locate food because the more eyes you have looking for food, the more likely you are to find it.

So as social birds, brown gnauties have a variety of different ways that they communicate. They communicate with their different vocalizations. They also have displays that they make for each other. One of which is nodding their heads, moving the head up and down. And that is where supposedly the common name came from. knotty comes from this nodding behavior that they have, this display. And that really shows off that white or light gray forehead and crown, there's a lot of contrast between the head and the rest of the body. And so when the bird is nodding, maybe that's a very conspicuous display.

Another conspicuous display is when one naughty communicates to another naughty by opening its bill very wide in a behavior called gaping. And the inside of the mouth is bright, colored. It's kind of a reddish orange color. And this is sometimes used in an aggressive display. One noddy is displeased with another noddy and he's like, hey bro, look at the inside of my mouth. Do you see this? Do you see this red color? You better step off, bro. Don't make me open my mouth any wider. Somehow that communicates important information. So as I just mentioned, the common name noddy comes from this behavior of nodding. But how about the scientific name, Anus Stolidus. A-N-O-U-S, again is the genus, Anus, and then Stolidus. Now, if you've ever heard of the

word in English stolid, you might not be surprised when I say that the name of this bird, the scientific name, means that it's stupid or foolish. Because Anus is Greek for stupid and Stolidus is Latin for stupid, more or less, foolish or unmindful. And the explanation is that when And sailors were first encountering these birds, the birds were unafraid and unconcerned about humans. So humans could basically just walk right up to them and grab them or whatever, maybe eat them, I guess, because, you know, that's what humans do. We can't just leave stuff alone.

So people concluded that these birds must be stupid if they don't react to people. And of course, that couldn't be further from the truth. These birds are likely to be fairly intelligent. They have complex social lives, that sort of thing. So they're anything but stupid, but the scientific name still captures that first impression. The Brown Nottie is in the family Laredi. And if you listened to episode 47 of the Science of Birds podcast, you will remember that the family Laredi is the family of gulls, turns, skimmers, and yes, noughties.

The genus Anus has five species. And these are all the noughties of the world. There's the brown knotty, lesser knotty, black knotty, gray knotty, and blue gray knotty. And the brown knotty is the largest of all five. Now, one interesting characteristic of the noddies that separates them out from other members of the family. Larity is that the noddies are the only species in that family that nest, at least sometimes, in trees and shrubs. And that also includes the close relative of the noddies, which is the white turn. those guys nest in trees as well.

So I mentioned that this is a tropical bird, I think I did anyway. This species, the brown knotty, is circumtropical in its distribution, meaning that you find this species in the tropical oceans and seas of the world. The Atlantic, Pacific, Indian Ocean, Caribbean, and so on. And it is, I would say, a fairly or truly pelagic bird. These birds are typically found far out to sea, not near. major continents. During the breeding season, they are found on small tropical or subtropical islands, like little sandy atolls or quays, and the best breeding habitat is an island that is

free of any mammalian predators. And of course, in some islands, many islands, humans have introduced non-native predators like rats and cats, and those can be devastating to brown, naughty colonies. So do these birds migrate? Well, ornithologists don't really know. It's kind of a hard thing to study in this species. As a tropical seabird, they probably don't migrate in great numbers the way we imagine other birds doing. For the most part, we just don't really know, so it's hard to say what they do exactly. But we do know that they tend to return to the same islands and sometimes even the same nesting site year after year during the breeding season. Although it's a hard to say breeding season for this tropical species because they tend to breed year-round,

and when conditions are good, they will breed multiple times within a single year. With respect to conservation, the news is fairly good for the brown knotty. The IUCN has this bird in the category of least concern. It has a fairly large global population, so even though locally there are probably colonies that are suffering from various issues, overall the species is doing pretty well. So what do Brown Notties eat? Well, the diet is primarily small marine fish and cephalopods like squid. But these birds, they forage at the surface.

That's their specialty. They use that long pointed, down-curved bill to pluck things from the surface. They particularly like schooling fish, like sardines and anchovies, or juvenile reef fish, or again, squid that are at the surface. and they have those kind of short, broad wings that allow them a really strong, direct flight, and they fly low over the water, and they can even hover for brief periods of time. And that allows them to, again, pluck things off the surface. Now, unlike their cousins, the turns, these guys rarely, if ever, plunge dive.

So they don't dive into the water. They just hover and then pluck things from the surface or grab things as they're flying by. And they're often doing this in groups. Again, this is a gregarious species, and they might even do it with other species of turns or boobies. And one of their foraging strategies is to follow schools of predatory fish like tuna or to follow dolphins. The predators drive the small fish to the surface, and that's when the noddies can pluck the small fish from the water. Brown knotty sometimes will actually catch fish in mid-air, like they can catch flying fish in mid-air, which is really remarkable. That's just a testament to how agile these birds are.

All right. So, so far we've talked about what these birds look like. We've talked about their family, their distribution, their habitat. So let's talk about breeding. This is a monogamous species. Pairs tend to stay together year after year, and they reinforce their bond through courtship behavior. And it's in courtship where we again see this nodding behavior,

where the birds will face off with each other and just nodding. at each other, and they look like they're just being very agreeable. You know, they're just like, yeah, yeah, they just nod, nod. And everybody's like, yeah, totally, yeah, exactly, what you said. Yeah, oh, yeah, totally. They're very agreeable, these birds, seemingly. So there's this bowing, this nodding and bobbing behavior. They also have courtship flights that helps them reestablish their bonds.

There's mutual preening, and the male will often bring a fish to the female. So courtship feeding is another part of this. And this is taking place in breeding colonies. Some of these colonies may just be a handful of pears or there might be many thousands of pears. And they can nest quite densely where the breeding habitat is good, you know, where there's lots of food and lots of nesting habitat. And in these colonies, each mated pair defends their own small nesting territory. And there can be squabbles for territory among different pairs where, again, they may be doing this nodding behavior, they're gaping, you know, showing the orange lining of their mouths, that sort of thing.

There's lots of squabbling in a colony. So you have a bonded pair. They make a nest, and the nest is not really all that elaborate. It can be just barely a scrape on the ground. These birds will nest on the ground sometimes, or they might pile up some sticks in a bush or on a cliff. So they usually like elevated sites, but when there are no elevated sites, they will nest on the ground.

But there's a lot of variability in where these birds nest. And as I mentioned, they tend to return to the same breeding colony year after year, and they might even use the same nest site year after year. A pair of brown knoties makes only one egg per breeding attempt. Now, that might be one egg per year, if they only breed once a year, or in cases where in tropical areas they breed multiple times, then each time they would make one egg. After the egg is laid, both parents share in the duty of incubation. and that takes about 33 to 36 days before the egg hatches. And when it does hatch, out pops a cute little baby brown naughty. It's covered in soft down feathers.

And there's quite a bit of variation in the color of that down. It's sort of geographically variable. Maybe it provides camouflage that varies regionally or geographically. But in any case, the chicks are basically helpless. They depend on their parents entirely for feeding for a while. And as the parents are taking care of the chick, they basically alternate duties. One of them will stand guard and brood the chick while the other flies off and forages for food. And this is all pretty intense in the first few weeks.

The foraging parent comes back and regurgitates food into the baby's mouth, and that might be again small fish or squid. And this diet, this high protein diet, allows the chick to reach basically adult weight within just a few weeks. And after about six or seven weeks, the chick is, the chick fledges. And even after it's able to fly and be relatively independent, it actually does depend on its parents for at least a few weeks, if not sometimes several months afterwards. But eventually, our young brown knotty learns to become independent. It learns all the strategies for plucking fish off the surface of the ocean. It learns how to nod its head at its buddies and its rivals. and its potential mates, although that might be instinctual, and then it's off on its own.

And there's not a lot of data on how long a brown naughty lives, but at least there's some data that suggests they can live 25 years or more, so it's a fairly long-lived seabird. And with that, that does it for random bird Thursday. That's just a little bit about the brown naughty, a bird that maybe you've never heard of, maybe you have, maybe you've seen them many times. I've seen them a couple places around the world, and I think it's a beautiful bird, it's an interesting bird. The times I've seen them, yeah, they've been in flocks, and they've been flying around on the surface of the water. They're really fun to watch.

So I hope you get a chance to see the brown naughty someday if you haven't already. And I hope you enjoyed this random bird Thursday, the very first one ever. Let me know what you think about it. My email address is Ivan at scienceofbirds.com. And I didn't mention at the beginning that I'm actually recording this in Japan. right now. I'm traveling. And so if you hear kind of, if the audio isn't amazing, that's why I'm recording this in a guest house right now. There's lots of room echo. I'm going to try to edit all that out and make it sound good, but you never know. But yeah, I hope you're doing great and I

will talk to you next time. Cheers.