7 Wacky Ways Birds Use Feathers


SciShow is supported by Skillshare. [INTRO ♪] You don’t need to know much about birds
to realize that their feathers are pretty awesome. They come in a dazzling array of shapes and colors, they keep birds warm and dry, and of course, allow them to fly. And since feathers are made out of the protein keratin, they’re also super strong and mostly waterproof. But that’s not all they can do. Thanks to millions of years of evolution, there are other, lesser-known functions of feathers that are equally cool, and many of them give certain birds unique abilities. Here are seven of them. We generally think of birds using their mouths to make sounds—or, more accurately, their vocal organs, called syrinxes. But feathers can also do the trick. One example is with male club-winged manakins, super cute little birds that live in South America. They use their feathers for mating calls as
part of an elaborate dance. Their club-shaped wings include a few special feathers, which happen to be shaped so that they rub against each other and produce high-pitched sounds—like adorable car horns. Ornithologist Kim Bostwick discovered this unique ability about a decade ago after seeing video of the birds’ courtship behavior slowed way down. She realized that individually, moving the
feathers did very little acoustically. But when they moved together very quickly, one feather, which is bent, strikes another, which has seven ridges on it. This ultimately allows the feather to
vibrate at 1500 cycles per second and create that high pitch. The mechanism is essentially the same as what crickets use to create their chirps, or what scientists call stridulation. Other birds make audible noises with their feathers to attract mates, too, but use other methods. For example, male American woodcocks fly extremely high in the air and flap their wings very fast, making characteristic twittering sounds. This is thought to be from what’s called aeroelastic flutter, which basically comes down to air moving past feathers. In the woodcock’s case, they have very narrow feathers at the edge of their wings, and the gaps in-between them create a whistling sound. Hummingbirds also make noise this way, using
their tail feathers. If enough feathers vibrate at the same frequency,
it can increase the volume of the sound. Next, instead of creating sound, some feathers play an important role in dampening it. If you’re a bird, especially a fairly large one, flapping your wings or even just gliding can make a lot of noise. And if you’re trying to hunt, that racket
is not exactly helpful. Most birds of prey, or what ornithologists call raptors, are usually such fast flyers that sound isn’t necessarily an issue. But owls move much more slowly, so stealth is key. The secret to their near-silent hunting ability
is three special feather features. First, there are serrations, or comb-like
structures, right where air first hits the wing. These break up the air as it moves across
the wing, reducing turbulence and overall noise. Then, at the trailing edge, or rear part of the wing, there are wispy fringes, which scientists think help smooth the airflow as it comes off the wings. Finally, a soft, velvety covering on the tops
of the wings forms a microscopic mesh that is exceptionally good at absorbing sound. These strategies are so effective at noise-reduction that engineers are now borrowing the designs for use on planes and wind turbines, and they’ve already had some success with 3D-printed, owl-inspired coatings in preliminary tests. But stealth may not be the only reason driving
the need for silence. Biologists studying owl evolution think keeping quiet is important not just to avoid tipping off prey, but also for accurately detecting it, which is largely done by hearing. And hearing also depends on, what else? Feathers! Feathers are critical for owl hearing, but
it’s not in the way you might think. The iconic ear tufts may look like ears, but scientists aren’t sure what they do—maybe they’re used as camouflage, or some kind of visual display. But either way, they are not for listening. Instead, hearing depends on owls’ heart-shaped faces and on what are called facial discs: the concave shape around each of their eyes. This area is lined with stiff reflector feathers, which amplify and direct sound waves into owls’ ears. They’re basically like radar dishes. These feathers have abnormally thick centralshafts and are packed extremely close together, just about as close as they physically can be. That makes for a good reflecting surface, and it allows owls to hear and pinpoint the source of very soft noises—which is kind of their thing. The special feather-lined discs are thought
to be one reason why owls are such expert hunters. After all, they’re really good at nabbing mice or voles, or whatever might look tasty, and most of them do it at night. Most other raptors hunt during the day and
have excellent vision. A few also have facial discs, which helps them hear better, but they’re less pronounced than in owls. Owl vision isn’t too shabby, either, but biologists have found that, thanks to their superior hearing, they can still hunt even in complete darkness. Without these facial feathers, though, they tend to misjudge the location of quiet sounds—at least, according to one experiment with a barn owl. While owl feathers are finely tuned for nocturnal hunting, birds known as grebes use their feathers in a less impressive, but still important way: They eat them. Specifically, to slow digestion and prevent
pokey fish bones and insect or crustacean parts from damaging their digestive tracts. This is maybe the strangest feather function, and grebes are the only birds known to do it. But it does have some logic. Typically, birds that have trouble breaking down hard foods will eat tiny stones so that the rocks can grind up the food in their gizzards, which make up one part of a bird’s stomach. It’s kind of like having a mortar and pestle in your body, because nature is just really hardcore that way. But grebes, for unknown reasons, don’t do this, and just rely on chemical digestion in their stomachs. Scientists think the feathers—which can
fill up to half of the gizzard—do two things. First, they slow digestion down, forming feather balls that the bird will eventually cough back up. That gives things like bones time to dissolve. A second, smaller feather ball also forms in a later part of the digestive tract called the pyloric pouch. This is the last stage before food moves into the bird’s intestines, so any non-dissolved sharp bits could be a problem if they make it through. So the feathers here are thought to filter
out all the possibly dangerous items. This strange habit, then, of self-plucking and consumption, seems to be related to the grebe’s diet. But that does not make it any less bizarre. Other water-based birds use their feathers
in some strange ways. Black herons in Africa, for example, fish
with a technique known as canopy feeding. In this method, the bird covers its head and
wraps its wings in a circle. It fans out its dark feathers to form an umbrella, which it then hunts under—like a little fishing hut. The exact reason for the canopy is unclear, but some scientists think this method scares off tiny fish, while leaving the larger and medium-sized ones to the herons. It’s also possible the shade draws fish
in or reduces glare. Green herons, which live in North America
and Central America, have also been known to drop feathers onto the water to attract fish. This kind of bait-fishing doesn’t always work, and isn’t restricted to feathers, but it is a relatively rare case of a bird using a tool. One of the more impressive feather adaptations belongs to the sandgrouse, a desert-dwelling, pigeon-like bird. Since water is at a premium, and baby birds can’t yet fly, adult birds—usually the males—use specialized belly feathers to pick up water and ferry it back to their nests. Which is a little bit adorable. Males collect water by walking into a shallow pool, and in bursts, rocking their bodies back and forth—a filling process that can take 15 minutes. The feathers themselves pick up water thanks
to their unique structure. When dry, the feathers have coiled barbules,
the secondary branches on feathers. But when they get wet, the barbules naturally uncoil, and their hair-like extensions pull in water through capillary action. That’s when water sticks to the walls of a
thin tube enough to pull it up, despite gravity. While it doesn’t sound like a lot, a single bird can pick up 40 milliliters this way—plenty for a baby bird. Once the adult flies back, chicks then kind of “milk” the feathers for their liquid. Biologists studying sandgrouse suspect that one advantage to this method is that the adults don’t have to sacrifice any of their own water intake to feed the chicks. They can just soak their belly feathers, and
avoid any messy parent-child competition. Finally, most birds have scales on their feet, but a few have feathers, including northern birds called ptarmigans, which use them like snowshoes. The added feathers quadruple the area of their foot, spreading out the bird’s weight and making it less likely they’ll sink down into the snow. We know this thanks to one curious Canadian physiologist back in the 1970s, who tested this function in three different species of ptarmigans. He plucked the foot feathers from some birds, and left them intact in others, then measured how much each sank into the snow. He found that feathering reduced the sinking by about half, and concluded that this feather adaptation probably helps the birds save a lot of energy when traveling. If that’s not amazing enough, though, it turns out that some species grow these feathery snowshoes every year. In the summer, they don’t need the feathers,
so they molt them off. But by the time winter rolls around, they’ve
grown out their claws and sprouted bright, white feathery shoes, which scientists think might also help keep their feet warm. Clearly, there’s a lot more to feathers
than just flight—as cool as flying is. Feathers are wonderful soundmakers, they’re water bottles, and they even come in handy as snowshoes. As a bonus for us, there’s also plenty of ways we can benefit from some of these remarkable adaptations—like owls and their ultra-stealthy feathers. Which means we’ll have much more to
thank birds for. Thank you for watching this episode of SciShow! And thanks to Skillshare for sponsoring this
episode and this whole week of SciShow. Skillshare is an online learning community with over 20,000 classes in everything from accounting to writing. Some of their most fun and popular classes are in art, like this one taught by painter Sharone Stevens on how to paint watercolor feathers. This relaxing class covers everything you’ll need to paint realistic styles of feather, from bluebird to peacock. She covers the basics for beginners, but the lessons never lag, if you’re a more advanced watercolor painter, either. Right now Skillshare is offering SciShow viewers 2 months of free unlimited access to Skillshare by clicking on the link below. So follow the link to take this class, or
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100 thoughts on “7 Wacky Ways Birds Use Feathers

  1. For number 5, is it possible that it just reduces glare and makes it easier to pinpoint fish? Like when you're trying to see in a window and you try and shadow it around your face so that the reflections don't make it really hard to see.

  2. so… if you stick some old traffic cones on the front of a car and a couple old brooms to the back it'll be a silent stealth car?

  3. AFAIK, they serve at least 3 more purposes:
    Temperature control
    Trapping poisons (discarding them by dropping the feathers)
    Protection against physical damage.

  4. I love those ridges on owls wing fronts that break up the airflow and silence it.
    Not only because of the incredible idea by mother nature but because when I was kid, the BMW M3 had those on both mirrors as the first car ever and I remember me and others just in awe of the amazing mimikry of nature making it into a street legal car. Also, it worked PERFECTLY…

  5. As the great ZeFrank once said:
    "Try riding a bicycle at night and picking up a burrito with your feet based on the sound that it makes.
    That is how an Owl do."

  6. 8. Mocking birds are generally gray in color. But under each wing the feather patterns have a bright white stripe. When they walk along the ground hunting grasshoppers, they will quickly flick both wings up exposing these stripes and scaring the bugs off their resting spot. The mockingbird sees the hopping bug and instantly snatches it from the air. 🙂

  7. #5, as someone who grew up playing in a river alot I would guess the herrons create this shade to reduce glare to see in the water more clearly. In rivers every ripple made by the current had a small glare. Removing the sun every ripple and wave disappears and its like looking through glass.

  8. Birds use tools all the time…rocks to crack nuts, thorns to spear food, and even sticks to construct homes…not a new feature in birds.

  9. A Blue Heron once told me that his cousin, Black Heron, makes a feather canopy or fishing hut with it's feathers to block the Sun's reflection so it could see into the water better.

  10. So this is a question I've had in my head for a while. When did the proboscis evolve, I mean obviously when flowers arrive but my question is when bees and butterflies got them. These are 2 very different groups but hyminoptera have both the proboscis and other mouthparts in their group. So where butterflies once part of that group and evolved of is the fact that both groups of bugs have proboscis a form of convergent evolution?

  11. don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock don't make a bad joke about the name woodcock

  12. One of the older benefits humans have gained from feathers: the quill pen. A skilled illuminator, using a hand-carved quill pen, can make maps and pictures that are unmatched in their beauty and complexity, even when compared to their digital counterparts.

  13. Very cool video! I work with birds and enjoy nerding about them, but I've only heard of three of these seven obscure feather uses. It's so amazing how animals will do whatever works to survive. They don't read our textbooks about what feathers are "supposed" to do.

  14. We have a TV screen in the main room at my school and while I was waiting to get on the bus I noticed they were playing a scishow video on it. I was so happy.

  15. Evolution is fantastic isnt it? All animals are amazing, except for the horde of field mice that are quickly filling the rather large aquarium in my apartment thanks to my no kill traps. Too cold to just toss them outside, and with winter coming, I'd prefer they not freeze or starve to death. 14 of the little furry beasts so far. haven't heard anything in several days, so hopefully I got them all. Now to wait till spring to set them free about ten miles from here in the woods. Still, animals are amazing, even the field mice.

  16. I wonder if the rumors about the winged hussars are true, the story goes that their combined wings made a terrifyingly loud whistling noise as they rode to frighten the enemy's horses.

  17. Humming birds sound like an angry bee. I thought it was a bee or wasp when I had one smack into me in my garden, when I looked out at my garden from the window, I noticed it was a bird.

  18. So what ARE the sounds?????? At the very least you could have got a hummingbird sound from anywhere.
    The info is amazing, but …..

  19. What? The don't know why Black Heron form a hood? Dude, the hood's shadow blocks the reflective light so they can see what's under the surface of the water. I do this myself when I want to see what's on the bottom of a pond. For example, stop the video when you see the Black Heron in the water. Can you see what's under the water, or just the reflections on top of the water?

  20. I'm not even five minutes in and already I've learned that feathers can be used to make sound. Once again scishow surprises me.

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