Meet the Oilbird: A Bird that Thinks it’s a Bat


Thanks to Skillshare for supporting this episode,
and this whole week, of SciShow. [ ♪ Intro ] In the tropical rainforests of South America,
there’s a flying animal that lives in colonies in caves, emerges at night in search for food,
and navigates using echolocation. And I’m not talking about a bat. Believe it or not, I’m actually talking
about a bird, the bizarre oilbird, known to locals as the guácharo. Oilbirds diverged from their closest living
relatives 50 million years ago, and in a lot of ways, they’ve become more like bats than
other birds. They roost high up in caves, for example. One oilbird colony can include as many as
20,000 crow-sized birds. And since there’s not a lot of nesting material
available in a cave, they build their funnel-shaped nests out of a mixture of regurgitated fruit and their own feces. Sounds cozy, yeah? And like a lot of nocturnal animals, including
many bats, for the record, they have excellent night vision. They accomplish that by packing their retinas
with rods, the light receptors responsible for vision in dim lighting. In fact, oilbird retinas have the highest
density of rods of any known vertebrate: one million of them per square millimeter. Your retina has a max of about 150,000 rods
per square millimeter. These birds have so many rods that there’s
almost no room leftover for cones, the other light receptors, which handle visual acuity
and color. That means their view of the world is probably
fuzzy and dull. Even the world record holder for rod density
needs some light to see, though, so the birds eyes are no help in pitch black caverns. Which might be why they’re the only birds
that have figured out how to echolocate. To keep from getting confused in a densely
populated cave, each bird clicks at a slightly different frequency. And unlike bats, oilbirds’ clicks are audible
to human ears, so if you were standing in one of these caves when the birds return to rest, you’d hear quite the cacophony. Oilbirds’ resemblance to bats is a classic
example of convergent evolution, where different animals facing similar pressures from natural selection end up with similar traits. They’re so bat-like, that you would think
we’d call them batbirds. But if you’ve been wondering where that
name came from, yes, there’s a story there. Oilbird comes from the fact that their favorite
food is the fatty fruit of the oil palm. Baby oilbirds in particular become so plump
from their palm-rich diet that indigenous people in Venezuela used to collect chicks so they could render their fat in pots to use as fuel. You know, the more I think about it, the more
I like batbirds instead. Maybe it’s time for, like, a rebranding. Let’s try it out: Thanks, batbirds, for the reminder of just
how weird nature can be! So I know that you know bats and birds are different
classes of life, but there’s still a lot of differences just between species of birds. All this week we’ve been sharing Skillshare
classes we enjoyed, and thinking about oilbirds, made me curious if Skillshare offered a class
on bird identification. I found this one called The Casual Birder
taught by Sue Pulsipher, and it’s kind of a hidden gem on Skillshare. It’s like if David Attenborough was your
sweet aunt and you took a trip to the Galapagos islands together. At first it seems pretty basic, like a flamingo and
a hawk are both pretty easy to identify, but she goes into really interesting details about
all the birds she talks about, like that bill of flamingoes and how they use it to eat upside down! And she shares footage of other animals you’ll
see while birding, like, in the Galapagos, iguanas. I was surprised by how charming and fun this
class was, and it just goes to show that you no matter what you’re looking for, you can
probably find a class about it on Skillshare. Thanks to Skillshare for supporting SciShow and for offering all SciShow viewers two months of unlimited free classes. Click the link in the description to take
advantage of this offer, and support SciShow at the same time. And if you go birding or take Sue’s class,
let me know what you saw and learned in the comments. [ ♪ Outro ]

100 thoughts on “Meet the Oilbird: A Bird that Thinks it’s a Bat

  1. YESSS, im from Caripe in Monagas Venezuela. This is very accurate. They are spooky animals also very worshiped here, there's a giant Statue of a Guacharo in the middle of the town. The sound they make is terrifying, and Because of their very sensitive eyes to light sometimes they got lost in the mornings and can't go back to their caves

  2. That's so weird and cool! I would have never known about this awesome bird if Scishow hadn't made a video about it! Thanks!

  3. So if they are birds but have bat behavior as if a bat raise them… would it be alright to call them Robins?

    That was a bat/d joke/er.

    I'll show my way out…

  4. They used the bird as oil to burn ? well I think they should have used it they directly from the source which will give them more. This wouldn't happen if they were named batbirds 😂

  5. I wonder,…if you could turn your light sensitivity all the way up, could you see static in the air from propagating sound waves and other disturbaces?

  6. As soon as I saw the thumbnail I knew it was a guácharo! Venezuela es hermosa 💜
    You English speaking people don't have to call it oil bird or bat bird, you can call it watcharoo or something that sounds like guácharo.

  7. "Unlike bats, oilbirds clicks are audible to human ears"
    What? I clearly remember being able to hear bat echolocation multiple times in past.

  8. I came across these birds while crossing a cavern in Rio Claro, Colombia. I can assure you that “quite the cacophony” is an understatement. these bat birds are a thing straight out of your nightmares. Imagine being in a pitch black cavern, partly submerged in a mixture of bird poop and water, and hearing something that would probably sound like a zombie horde munching on a brain buffet. That is how the bat bird do.

    Still one of the best travel experiences yet 10/10 would recommend!

  9. " baby birds get so plump from the oil…"
    me: "aww cute!"
    "that they're used as fuel"
    me: "well that turned dark fast." 🙁

  10. NO, they are NOT the only birds that use echolocation. Several species of swifts also echolocate. The most extensively studied is the Edible Nest Swiftlet (Aerodramus fuciphagus). All of these swifts roost and reproduce in caves, and subsist on airborne insects and ballooning spiders, thus they are ecologically closer to cave roosting insectivorous microbats than Oilbirds, which feed on palm and other fruits.

    Both swifts and Oilbirds utter lower pitched calls (which are audible to Humans) than cave roosting bats utter when echolocating, thus their echolocation is less efficient than that of cave microbats. Most of the cacophony heard inside Oilbird caves is from their advertising calls; they shriek and cackle very loudly and persistently to advertise and defend nesting territories (small areas in cliff ledges) and locate their mates and offspring, which recognize each other by sound. The echolocating calls of Oilbirds are repetitive clicks, and are softer than their advertising and alarm calls, which must be heard over greater distances to be effective. If alarmed by Human or other intruders, the birds will utter even louder communal alarm calls in chorus.

    Oilbirds DON'T build nests. They simply claim and defend small spaces on cave ledges for nesting (and roosting), and these are covered by accumulations of droppings and regurgitated palm seeds (usually too large to pass through their gut, and Oilbirds don't crush them with the powerful gizzard of a seed eating bird; they simply regurgitate them, as owls regurgitate pellets of indigestible material) from their present, neighboring, and past occupants. Like owls, hawks, eagles, and colonially nesting seabirds and Rock Pigeons, they have evolved to thrive among accumulations of their own feces, and in the case of owls, hawks, and eagles, the accumulated bones, fur, and feathers regurgitated or left over from their prey. (That fluffy dark material that you see in videos of eagle and owl nests is mostly the fur and other remains of their prey, and in warm weather, it is teeming with maggots and other scavenging insects.)

    Oilbird chicks were collected for oil by local people for rendering COOKING oil, NOT fuel oil, or oil for fires. They are tropical birds, and the Human harvest of their nestlings was conducted by people living in tropical (no heat or fuel oil needed), non industrial, agricultural or hunter/gatherer societies that had no use for oil as fuel!

    The fungus Histoplasma capsulatum thrives in abundance in Oilbird caves, as it does in bat caves. Both Oilbird and New World tropical bat caves also host huge populations of giant Blaberus roaches, and the guano accumulations on the floors of these caves are literally seething with millions of these insects, along with growths of doomed, pale etiolated palm seedlings that germinated from regurgitated seeds in the darkness. The roaches are harmless to Humans unless you are allergic to them (and are now quite widely kept as 'pet' insects; they have very cool looking nymphs [subadults] that resemble trilobites), but Histoplasma is an opportunistic Human pathogen that can (rarely) cause fatal fungal meningitis if it invades the central nervous system, and infects the spinal cord and brain. Oilbird chick harvesters in Tingo Maria, Peru, referred to clinical Histoplasma infection as "Tingo Maria fever". The Tingo Maria National Park now includes and protects the Cueva de las Lechuzas that hosts the local Oilbirds (known locally as "Guacharos").

  11. Holy damn! I had forgotten all about these things when I actually visited a cave system where these lived! They're totally right, they do make noise while flying and one scared me so badly, but I'm easily frightened and it was the only one that came sort of close to the group; not surprised they'd be wary of a large group of humans.

    Idk if it was a coincidence but the caves we where in were flooded, with running water and even a pretty high jump that at least had a very deep pond at the end. So, at the very least, these birds are okay living that close to water.

    One last thing, these birds have whiskers! You can tell if you google close-ups of their faces. Idk if they can feel with them like cats do, but they look a lot like whiskers.

  12. I saw an albino turkey buzzard whilst traveling to work one day. Unfortunately, I neglected to take a picture of them.

  13. It's so crazy how animals do whatever works. Like, there's lots of fruit-eating birds during the day, but the buffet is open to the bird that can eat at night!

  14. It thinks it’s a bat…. really?!? Just cause that seems to be the only way we can explain its behavior doesn’t mean the bird actually thinks it’s a bat… we need to stop this terminology. It’s stupid!! It’s a bird that behaves like bats. It doesn’t think it’s a bat. It thinks it’s a bird!!!

  15. Whats weirder: the bird that wants to be a bat; or the bald primate that collects said bird's babies, to melt them down and turn them into fire?

  16. Skillshare needs more construction type classes. Not enough woodwork for example. They have a lot of digital classes, but not many analogue.

  17. Iv heard normal bat clicks before. They have to be close but i usually see a flash in the night sky thats almost invisible. More like a shadow flying through on a moon lit night. Pretty shore we dont get those cave birds in Australia. I heard bats in bali too.

  18. i love how they always talk about something (like how the birds navigate and sound) but never show anything… thx guys now i have to google the bird and watch other youtube videos to check them out properly

  19. How on Earth does SciShow have 5.3 million subscribers, but only 150,000 people have seen this in the two weeks it's been up? YouTube, what are you doing? Educational programming like this should be at the top of people's recommendations, and subscription lists, and everything else.

  20. I woke up one night I left YouTube on and saw skill share tiptoeing out of my room…there were used condoms EVERYWHERE

  21. Fins and wings are also broad examples of convergent evolution. Many types of organisms have had to become better suited for life underwater or in the air, but coming from different phylogenetic lineages, they have had to use different routes to arrive at the same or very similar traits: bird wings, bat wings and insect wings are totally different yet they all serve the same function.

  22. I learned about these birds in my childhood from some book about nature (Gerald Darell maybe?), but saw a picture for the first time.

    Next life goal: travel to Venezuela and see them with my own eyes!

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