Consider The Nocturnal, Whiskered Oilbird
At first glance, the oilbird doesn’t seem so strange. It’s a chestnut-colored, hawk-like bird that lives in South America. But with a closer look, its strange qualities start to stack up.
Oilbirds are nocturnal creatures that roost in caves in huge colonies. Sure, some other birds, like nightjars, do the same. But oilbirds also have a triple threat for navigating the darkness: They’re one of the few birds that use echolocation, they have incredible eyesight and sense of smell, and they have whiskers on their faces. Unlike bats, their echolocating peers, oilbirds exclusively live off a fruit diet, confounding researchers looking into why they evolved so many specialized traits.
They also have an incredible screech—when deployed in large numbers, it’s easy to understand why local populations have given them a name that translates to “little devils.”
Two adult oilbirds guard a young bird who sits in a nest. Footage courtesy of Mike Rutherford.
“It’s wrong in every way, as far as birds go,” says researcher Mike Rutherford, curator of zoology and anatomy at the Hunterian museum at the University of Glasgow in Scotland. Rutherford studied oilbirds in Trinidadian caves to learn more about their population sizes. “A lot of people say every species is unique, but some are more than others, and the oilbird is one of those.”
Rutherford joins Ira and SciFri producer Kathleen Davis to make the argument that the oilbird deserves to be labeled a charismatic creature, and join the ranks of the Charismatic Creature Corner.
Do you have a suggestion for a Charismatic Creature that might enter SciFri’s Charismatic Creature Corner Hall of Fame? Send us your suggestions via our SciFri Voxpop App, tweet @SciFri on Twitter with the hashtag #MyCharismaticCreature, or send us your suggestion over email with the subject line My Charismatic Creature. We can’t wait to hear from you!
*Editor’s Note 8/9/2021: This page has been updated to correct a typo that incorrectly referenced “nightjars” as “nightjays.” We regret the error.
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Mike Rutherford is Curator of Zoology and Anatomy at the Hunterian Museum at the University of Glasgow in Scotland.
IRA FLATOW: Well, it’s the end of another week. So what better way to celebrate than with one of our favorite segments? It’s time for another Charismatic Creature Corner.
And joining me as always is our Charismatic Creature Correspondent Kathleen Davis. Hi, Kathleen.
KATHLEEN DAVIS: I’m glad to be back, Ira.
IRA FLATOW: So which Charismatic Creature, potential Charismatic Creature have you brought us this time?
KATHLEEN DAVIS: So this week’s Charismatic Creature candidate I’d like to highlight is one that doesn’t seem that weird from first glance. But the more you learn about it, the stranger it becomes. Are you ready?
IRA FLATOW: Yeah, hit me.
KATHLEEN DAVIS: So this week, we are talking about the oilbird. Do you know anything about this bird?
IRA FLATOW: You know, it sounds like a logo for a fossil fuel company. No, I never heard of it, as you can tell.
KATHLEEN DAVIS: Well, it is unlike any bird I have ever researched. So it lives in South American caves. It uses echolocation. And it has whiskers, just to name a few things about it.
IRA FLATOW: Whoa, whiskers? A bird, really?
KATHLEEN DAVIS: Yeah, really. But as always, I am no connoisseur of this creature, just a fan from afar. So I have recruited an expert to help explain just how charismatic this creature is.
So help me welcome our guest. Mike Rutherford is curator of zoology and anatomy at the Hunterian, a museum at the University of Glasgow in Scotland. He used to live in Trinidad and Tobago where he studied oilbirds in the wild. Welcome to Science Friday.
MIKE RUTHERFORD: Thank you very much for having me.
IRA FLATOW: Nice to meet you, Mike.
MIKE RUTHERFORD: No problem. Nice to meet you too, Ira.
IRA FLATOW: All right, so Kathleen gave us a little preview of what makes these birds special. But Mike, can we start with the basics? What does an oilbird look like?
MIKE RUTHERFORD: Imagine, if you will, maybe a super-streamlined owl, because they’re a night bird. They’re a nocturnal bird, but more like a cross between an own and a hawk of some sort. I don’t know people, your listeners, are familiar with night jars? They’re probably most similar to those.
But to give you a basic description, they’re kind of a Rufous brown color, chestnut brown. They are about 45 centimeters long from sort of tip of the tail to the nose. For your American listeners, that’s something like 18 inches or a foot and a half. And the wingspan is about 3 and 1/2 feet, you know, so just over a meter. So they’re quite a big bird.
And covering the body as well as all that nice, brown, chestnut background, they’ve got white spots all over, long tail feathers, long end wing feathers, a very curved hooked beak which makes them reminiscent of a hawk, not that they eat anything like the same sort of diet as hawks. And as Kathleen mentioned, they also have these what are called rictal bristles, or whiskers, around the mouth part.
IRA FLATOW: Yeah, that’s what intrigues me. Why would a bird have whiskers?
MIKE RUTHERFORD: Well, this is a big question. No one is really sure of the exact purpose of a rictal bristles, possibly to do with the sensing air movements as they’re sort of feeding, as they’re flying around. There has been lots of experimental studies over the years, but no one has really come up with a satisfactory answer just yet. And they are found in different birds which have different diets and different lifestyles, so there is no real hard and fast kind of answer for that one, I’m afraid.
IRA FLATOW: And the name oil bird, where does that come from?
MIKE RUTHERFORD: Yeah, so that’s a bit of a gruesome background. You kind of mentioned sort of this, a logo for a fossil fuel company. But before we had oil being pumped out of the ground, people actually harvested oilbirds and used the oily fat that came from them for purposes such as lighting lamps and for cooking.
The young are not very attractive at all. They are like big, green blobs. So when you see one sitting on the nest, it’s kind of a big fatty blob. And actually, the young can weigh more than an adult, because they get fed on this very rich diet of various palm tree seeds. And they just get fatter, and fatter, and fatter. And eventually, when they grow their proper flight feathers, then they sort of tone down a bit.
So the “oilbird” comes from the purpose they’re used for, but it’s just one of the names that’s been given to the birds over the years. One old, old name that I came across was Trinidad goat sucker, but that name wasn’t useful too long.
IRA FLATOW: I can imagine.
MIKE RUTHERFORD: A little local name in various parts of South America where they come from was a guacharo. And that sort of translates roughly as “ones who cry and lament.” And this also at least to another local name in Trinidad where they’re found called the diablotin, or little devil. And these, both of these names refer to the ghastly screeching noises that the birds make when they’re disturbed, when you go into their cave habitats.
KATHLEEN DAVIS: Well, speaking of what they sound like, I have to play a clip for Ira and our listeners so that they truly understand why they’re called these little devils. And sorry in advance due to everyone who is about to hear those for the first time.
IRA FLATOW: Whoa, that just blew me away.
MIKE RUTHERFORD: So that’s probably several hundred birds all flying around at once inside a cave. And someone else described it, when you are in the cave, it sounds like you’re standing or flying along in an open-top airplane that’s so noisy you can’t have a proper conversation.
IRA FLATOW: Wow, that really was noisy. You know, we’ve got to talk about the echolocation, speaking of noise, that was mentioned earlier. Do they use it like bats do to find food?
MIKE RUTHERFORD: They use it for a variety of purposes. So they nest inside caverns and caves. So being able to navigate inside these long, dark spaces, the echolocation is very useful.
But they also, when they go out searching through the tropical forest at night, they possibly use the echolocation to navigate through trees as well, because they tend to swoop down on palm trees and other types of trees that produce big, juicy seeds and pluck off the seeds in flight. And they’re doing this in the darkness. So although they’ve got very good night vision as well, echolocation probably does help with some of that close-up maneuvering.
KATHLEEN DAVIS: And they’re nocturnal too, as you said. I mean, what would be the benefit for this bird to be going out and getting fruit at night as opposed to during the day? Well, i”m not 100% sure. But I guess It would be a useful way of finding your own niche.
They’re not having to compete against other fruit eaters during the day, where, at nighttime, there is not that same competition, possibly. And also, because they live in caves, which are a nice safe place for nesting– so moving in and out of caves under cover of darkness gives even less clue to the predators as where they’re coming from. So there is a lot of potential reasons for being a nighttime feeder.
IRA FLATOW: Huh. So they live in caves, which makes me think that their eyesight is not too good, because they’re in the dark all the time.
MIKE RUTHERFORD: No, they have fantastic eyesight. These are very big eyes–
IRA FLATOW: Really?
MIKE RUTHERFORD: –look at big, black, limpid pools. They live out in the forest when they’re foraging. They’re only returning to the caves, really, for back to the nest.
They do spend some time out in the open, as it were. And just to mention, the third really good sense is they have great sense of smell, which is quite unusual for birds. Not many birds use their sense of smell. But it’s thought that the oilbirds can help find ripened fruit when they’re flying through the woods, because a lot of the very ripe palm trees will have a distinctive odor.
KATHLEEN DAVIS: Reminding our listeners that this is Science Friday from WNYC Studios. We’re talking to oilbird enthusiast Mike Rutherford. So one of the big things that usually convinces people that a creature is charismatic or not is their social structure. What is the oilbird social structure like?
MIKE RUTHERFORD: Well, they’re very gregarious. They like roosting in large numbers. And the noise you heard, the screeching in the caverns, that’s not what it’s like all the time, fortunately. Otherwise, I think the birds would drive each other insane.
That only happens when you’ve got a disturbance like a researcher such as myself wandering into their cave. But if you go in, switch off your torches, sit down, and just relax, then, within about five, 10 minutes, the birds are all quieting down. And there is just these kind of occasional clicks and chirps.
And they obviously, they’re sometimes nesting several of them on sort of short ledge on the side of the cave. They’re quite comfortable with each other. They definitely seem to get along well enough in close quarters.
But the foraging, I think from what some of our studies show, the attaching data transmitters, GPS transmitters to the birds, when they go out to the caves, we think they tend to sort of spread out into forests. You know, they don’t go out en masse. But there is not much known about that. Trying to spot birds in a tropical rainforest in the middle of the night is a pretty tricky job, so that’s why most of the research that’s been done on them has focused on their life in the caves.
IRA FLATOW: Mike, what do you like most about this bird?
MIKE RUTHERFORD: It’s wrong in every way as far as birds go. It’s just different in every way. That’s what I love. They’re just completely individual.
A lot of people say, every species is unique. But some are more unique than others. And the oilbird is one of those. The echolocation, this roosting in caves, yeah, some other animals do that. But OK, throw in as well being a fruit eater, that just makes it even weirder.
And then just looking so spectacularly beautiful as well– you know, they have a beautiful shape. Except when they’re young, they’re kind of ugly. And I’m just having all these crazy names, the crazy behavior, really, it’s just a whole package deal for me. They just tick all the boxes for what makes an animal interesting.
KATHLEEN DAVIS: Well, we are out of time. So Ira, I have to ask you, do you think that the oilbird is charismatic?
IRA FLATOW: You know, this is a tough one, because I was leaning toward no. I was thinking it really was not charismatic. It has those crazy bird calls. And it’s all that noise. But when I asked Mike what he likes most about a bird, and he says it’s wrong in every way, I can relate to that. So I think I’m going to have to say, it is charismatic, but just by a whisker.
KATHLEEN DAVIS: And Mike, I think I know your answer, but do you think that the oilbird is charismatic?
MIKE RUTHERFORD: Oh yes, 100%.
IRA FLATOW: Oh, there you have it. Well, I want to– that’s terrific. I want to thank Mike for joining us. Thank you for joining us and enlightening us about the oilbird.
MIKE RUTHERFORD: My pleasure.
IRA FLATOW: Mike Rutherford, curator of zoology and anatomy at the Hunterian. That’s a museum at the University of Glasgow in Scotland. And Kathleen, I hear something interesting is happening in Charismatic Creature Corner land? Tell us about that.
KATHLEEN DAVIS: Yes. So this fall, we are going to hold the first ever Charismatic Creature Carnival.
IRA FLATOW: Whoa.
KATHLEEN DAVIS: And we need the help of our listeners to pull this off.
IRA FLATOW: OK, so what do our listeners need to do?
KATHLEEN DAVIS: So all you wonderful people listening at home need to send us your suggestions for charismatic creatures you would like Science Friday to talk about. So give us your weirdest, funkiest, most charismatic creatures. It doesn’t matter if it lives on land, in water, if it’s super big or microscopic. It can even be extinct. But we need to know what charismatic creatures you would like us to talk about.
So if you are listening and you’ve got a great charismatic creature up your sleeve you have been waiting for us to talk about, let us know about it. And you can do that a few different ways. So the first way, you can send us a voice memo on our SciFri VoxPop app.
The second way, you can also tweet at us. Tag us @SciFri on Twitter and tell us your suggestion. And make sure to hashtag #MyCharismaticCreature. That is very important so we can find it, hashtag #MyCharismaticCreature, all one word.
IRA FLATOW: OK, great. And what about good, old-fashioned email?
KATHLEEN DAVIS: Yeah, you can also email us your suggestions. That address is firstname.lastname@example.org. And make sure in the subject line to put “My Charismatic Creature” so we can pick it out easily.
IRA FLATOW: So again, #MyCharismaticCreature is the hashtag on Twitter and the subject line on email?
KATHLEEN DAVIS: Yup. And this fall, we will hold our first Charismatic Creature Carnival, where we’re going to talk about a bunch of the listener-suggested creatures. And eventually, we’ll have our listeners vote for their favorite creature. So at the end of all of that, we will have our very first true inductee of the Charismatic Creature Corner Hall of Fame.
IRA FLATOW: You know, it all sounds great, Kathleen. We are excited to kick off the carnival a little bit later this year.
KATHLEEN DAVIS: It’ll be great.
IRA FLATOW: SciFri producer Kathleen Davis– thank you for joining us again.
KATHLEEN DAVIS: Thanks so much for having me.