The Science of Birds - Random Bird Thursday: A Duet-singer That Uses Bones for Decoration

Episode Date: July 16, 2026

In each Random Bird Thursday (RBT) episode, the goal 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 certainly deserve some appreciation and attention. ~~~~~~~~~~~~~~~~~⚠️ SPOILER ALERT!The featured species in this episode is the Rufous Cacholote (Pseudoseisura unirufa).Sound Citations:Sjoerd Mayer, XC3496. Accessible at www.xeno-canto.org/3496.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 I'm pleased to tell you that it is Random Bird Thursday. Random Bird Thursday episodes are relatively short and punchy, and in each of these episodes I spotlight a bird species that isn't likely to get featured in a full-length Science of Birds podcast episode.

So Random Bird Thursday gives us this chance to celebrate species that we might otherwise overlook, a species among the over 11,000 bird species that are out there. There are so many possibilities. So who are we talking about today? Well, the only way to find out is pushing the random bird selector button, and here we go. Sweet, we have the Rufus Caccholote. The Rufus Cacolote, which has the scientific name Pseuoceruza. This is a South American bird,

and one of its Spanish names is Cacolote Crestigris. Crestigris, and another English name for this bird is gray-crested cacolote. So that's the connection with the Spanish name. Cresta-Greece, gray-crested. Okay, let's stop messing around and get into it. This is a passeron. bird, roughly the size of an American Robin or a European blackbird, but it has a large kind of stout body. And one of its most outstanding features is that it has this bushy crest

and a long, almost squared off tail with the outer pair of feathers being a little bit shorter than the central feathers. So the length of the bird is eight to eight and a half inches or so, and that's 20 to 21 centimeters. The eye is, you. yellow or a buff yellow. The bill is blue, gray, or gray. But the first thing you're going to notice is the overall plumage color. Adults are basically a bright reddish rufus color, thus the species name or the common name. And it's a little bit more pale on the underparts. Now, some individuals, and I'm not sure if these are, you know, this is just a individual to individual thing or a population thing, but some of them do in fact have a crest that is more gray.

distinctly gray. So thus the other name, gray-crested caccholote. So what does the Rufus Caccholote sound like? Well, it has a call where it's just kind of a single, low-amplitude chuck that it makes as a constant note. But the song is a descending series of notes, maybe four to ten notes, that accelerate into what is called a rattle, and it's described as kind of a bouncing ball pattern. And these birds often sing in duets with a male. and female. And good news, I actually have a recording of that. So we're going to listen to a duet of Rufus Cacchalotes, and this was recorded in Bolivia. Now, you won't be surprised after hearing that that one of the descriptors of this bird is that it is noisy and conspicuous. It spends time in the

trees and on the ground, and it's often found near human habitation around ranches and things, so it's a very familiar bird. So let's look a little more closely. So let's look a little more closely at the scientific name. Pseysura unarufa. So the genus, pseudosysoira, has pseudo in there, and you know that that means false. So what's sysura? Well, apparently that refers to a wagtail. It goes back to some names that were assigned by Greek people long time ago, so it's a little

confusing. I couldn't quite figure out why it's called a false wagtail. But it is what it is. But Unarufa, the specific epithet, the second part of the name, that's a little more straightforward. That means only Rufus. Unarufa, only Rufus. Because the bird is entirely Rufus. Reddish-Brown. Now maybe my specific epithet should be something like Unidufa, meaning that I'm only a Dufus. I don't know. I have to work on that. The Rufus Cacchalote is in the family Fernaridi, which has about 320,000.

species. This is a mega-diverse neotropical bird family. And you better believe I'll be doing a podcast episode on it at some point. It's shameful that I haven't already, but I'm getting there. So within that mega-diverse family of 320 species, there are four Cacholote species, all of them in the pseudo-sayura genus. So who is the closest relative of the bird we're talking about today? Well, that would be the Cachinga Cacholote, Pseudo-sayura-cristata. because these birds used to be considered the same species. They were all considered the Rufus Cacchalote, all populations. But that species was split into two in the year 2000

based on a paper that was published in the journal The Condor. The researchers were Kevin J. Zimmer and Andrew Whitaker, and the title of the paper is, The Rufus Cacchalote is two species. And so those researchers, they based that decision on how the bird, act and look and how they live, how they breed. So for example, these two groups, these two birds and these different, you know, they have different geographic areas and they don't recognize each other's songs, so in the wild they wouldn't naturally breed together. And the Kachinga Kacholote is actually

a cooperative breeder. So a breeding adults get help from other adults, and that is very different from what the Rufus Kachalote does, which is more just like typical monogamy. And the birds do look slightly different as well. The Rufus, aka gray-crested caccholote, has that potential gray patch of feathers on its head. And you don't see that in the Cachinga cacholote. And again, they live in different areas, different parts of South America. But at least when that decision was made in the year 2000, there was not genetic data to back up that decision. It was just all this other evidence that was enough to cause ornithology.

to split the species. And that's interesting because even back in 2000, a lot of those decisions were based on DNA, at least to an extent. These days, that's pretty standard. So I'm just pointing that out because often when I talk about these splits of species, there's some genetic data involved. Now, apparently there has been research since 2000 that has backed up the idea that these are different species. Research with genetics. Okay, so are there any subspecies within the Rufus Cacchalote, and the answer is a resounding, nope. So to be a little more specific about the distribution, this species is found in north-central and eastern Bolivia,

as well as southwestern Brazil and northern Paraguay. And that second area, that corresponds to the Pontinal region, if you've ever heard of that. It's a super-famous, super biologically rich place. My tour company, Wild Latitudes, does Brazil tours, and we always go to the Pontinal, but I've never led that tour. I've never been on it, never been to Brazil,

maybe someday. And then in terms of habitat for the Rufus Cacchalote, this bird lives in gallery forest, as well as deciduous woodlands and seasonally flooded savanna areas. And that would correspond to the Pontinal. That's what the Pontinal is. This is a resident species,

so it does not migrate as far as we know. And in terms of conservation, We have another happy report here. This one is least concern. It's in the least concern conservation category. So it's not endangered that we know of. And there apparently are no major threats to the species. Perhaps some habitat destruction.

But other than that, nothing specific. In terms of what the Cacallote creste gris eats, well, it eats mostly arthropods, insects and other things like spiders and millipedes and all that good stuff. but it seems that it also eats fruit and some seeds, and it feeds mostly terrestrily, so mostly on the ground. It's gleaning from low-hanging vegetation, probing, digging for prey in the ground, and it's a social forager, so it's often found the species is often seen foraging in pears.

Now, I mentioned earlier that this is probably a monogamous species. We don't have a lot of information about it. That is just an assumption. but it seems that that is what has been observed as opposed to that cooperative breeding scene in its closest relative. The nest is, there's some specific information about that. It's this big oblong mass of twigs and sticks, and some of these nests can be up to about two feet wide or 60 centimeters. The cacallotes use feathers, snail shells, crab shells, bones in the exterior of the nest. All kinds of good stuff.

maybe human skulls, who knows? There's an entrance on the bottom of the nest that leads through a tunnel that goes into this spherical inner chamber, and that chamber is often lined with bark and snake skin. Now, this is not the only bird that uses snake skin in its nest. As far as I know, ornithologists don't know exactly why birds do this other than that it might be some kind of predator deterrent, but it's interesting that that shows up in multiple species that are not closely related. Anyway, the nest is located off the ground. It's maybe 13 to 16 feet high, up in a tree or in a bush, and that's 4 to 5 meters.

Now, remember that we had the birds duetting, right? So they use that duetting to defend their territory. The pair does that to warn off other members of their species that, hey, this is the boundary of our territory. And with that loud duetting. and that is the end of the information that I have about the Rufus Cacchalote. We have scraped the bottom of the barrel for information. I have nothing about the eggs or anything else. But that wasn't bad. It gives us a little sense of this bird, and that's what we're here to do on random bird Thursday. I haven't seen this species.

I have not been in those areas where this species lives, so maybe if I do go to the Pontinol some day, I'll keep an eye out for the Rufus Caccholote, and that'll be really cool. I'll be like, hey, I did a random bird Thursday on that species. And I have to wonder about you. Have you seen this species? It is loud and conspicuous in those places,

so maybe you have if you visited that part of South America. Let me know. Tell me your story. My email address is Ivan at Scienceofbirds.com. That's it for today's random bird Thursday. Thank you so much for being here, and we'll see you in the next one. Cheers.