
The silence of the owls - prostoalex
https://www.knowablemagazine.org/article/technology/2020/how-owls-fly-without-making-a-sound?MvBriefArticleId=702
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symmitchry
I was attacked by a huge owl recently. It drew blood, and really hurt. I can
confirm it was entirely silent, in contrast to being attacked by a crow, which
makes an almost-avoidable swooshing sound.

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gnulinux
Why would an owl attack a huge mammal like a human? Are you a particularly
short person? Do owls attack other large mammals like deers, horses, bears
etc? That's very scary.

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dmoy
Sometimes your hair or hat can look like a tasty meal. Sometimes it's
territorial, if you're getting too close to a nest or whatever. Usually it's
one of those two.

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Judgmentality
A _long_ time ago, when I had much longer hair and would go running just about
every day, there was a block on my route where a bird would swoop down
constantly and attack me. I think it thought my hair was a bunch of worms or
something. It was a smaller bird, it couldn't really hurt me, but fuck that
thing flying around my face was terrifying. I quickly changed routes once I
realized it wasn't going to stop.

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seshagiric
To really appreciate how silent Owls are as compared to other birds, see this
excellent video from BBC:

[https://www.youtube.com/watch?v=d_FEaFgJyfA](https://www.youtube.com/watch?v=d_FEaFgJyfA)

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gibolt
They mention its light body without explaining how. You should Google "Naked
Owl" and see just how little their body actually is. Most of what you see is
just fluffy feathers

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Ididntdothis
Be careful with searches that have the “n” word. I once saw a picture of a
bear that had lost its hair due to a skin problem and wanted to show it to a
colleague. So I searched for “naked bear” which didn’t end well.

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sk0g
Bear is a gay "trope" or whatever it's called, so I would never make that
query as is! Might have had better luck with "naked bear -gay -man"?

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Ididntdothis
I guess this was a TIL for me :-)

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srikz
This video about Biomimicry is a great accompaniment for this article

[https://www.youtube.com/watch?v=iMtXqTmfta0](https://www.youtube.com/watch?v=iMtXqTmfta0)

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starpilot
Bird wings are actually optimized for different Reynolds numbers
([https://en.wikipedia.org/wiki/Reynolds_number](https://en.wikipedia.org/wiki/Reynolds_number)).
More flapping for smaller birds/insects, more gliding for larger (they fly
like airplanes almost).

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nullc
There are some horned owls that seem spend a lot of time on my property at
night. We like listening to them Who Who at each other.

Sometime last year one swooped over me while I was outside, I had no idea it
was there until it was feet away and it was gigantic. Startled the hell out of
me.

Only time I've ever actually seen them. I'd love to get some photographs of
them but because they move so silently they're hard to find.

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Baeocystin
I used to live on a ranch, lots of open space and a few tall trees near my
house. I decided to get a cheap night-vision monocular to check for coyotes
before I let my dogs out in the evening. The first night, just looking around
for fun, I was shocked by the _huge_ owls that were living in the trees, and
flying around looking for prey. They had learned to take flight as soon as I
opened the door, the noise + running dogs frequently kicking up a scurrying
meal for them. I'd lived there for a year, and had no idea. You couldn't hear
a thing, even with them swooping in for a kill just feet away. It was
incredible to watch!

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nullc
I now feel stupid. I have a LWIR camera. I can find the owls.

One of the big revelations from our security cameras is how much animal
activity that goes on which we'd otherwise have no idea about. We're visited
almost every night by skunks, racoons, and foxes... but we only see them first
hand a couple times a year.

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rcurry
A couple of other interesting things about owls - they can’t move their eyes,
which is why they have a few extra vertebrae that allow them to swing their
heads around so far, and some owls have offset ears that allow them to
calculate a glide path toward their prey, kind of similar to how aircraft use
ILS to stay on a glide path for landing.

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chrisbennet
I had a pet owl one summer. It would perch on my arm. It used to land on my
sisters window and walk back and forth to get fed I guess. (We had windows
that pivot up and out.)

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1e-9
Previous discussion:
[https://news.ycombinator.com/item?id=22809199](https://news.ycombinator.com/item?id=22809199)

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MaxBarraclough
I wonder if there's an 'engineering tradeoff' to their quiet flight. Would
they be quicker/more efficient if they weren't constrained to be quiet?

I suppose it's unlikely we have a clear answer to this.

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KineticLensman
Many owl feathers lack preen oil, meaning they are less waterproof than other
birds, increasing mortality in cold wet weather. Prolonged rain is very bad
for many owls.

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MaxBarraclough
Interesting. Is this an adaptation to increase their stealthiness?

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KineticLensman
Exactly

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jay-anderson
Owls can make some noise when they want to as well. My grandparents had an old
abandoned silo on their property that we knew some barn owls were roosting in.
We went out at dusk to watch them. It was amazing how quiet and graceful they
were. But they didn't like us being there and swooped down to yelled at us a
few times. Since we didn't hear them coming and it was quiet out they took us
by surprise and really made us jump.

It was also neat looking through their pellets at the bottom of the silo to
see what bones were recognizable.

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tobmlt
Good stuff. This reminds me of the "added mass swimmer" \-- theoretical
propulsion purely by the added mass effect, avoiding the shedding of vortices
(with the propulsion device working in water, or any suitably heavy fluid).
The navy has been funding studies into it for a while. Not going to work for
an owl though. Air is not heavy enough.

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und3rth3iP
Ever since learned that owls are mostly made up of feathers, I haven't been
the same.

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coldcode
I always wondered if one could build a drone as quiet as an owl.

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maxwell
Came to the comments hoping to hear about applying owl science to drones.

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filoeleven
This isn’t owl science, nor is it quiet, but it is an ornithopter that uses
bird wing biomimicry. It’s also the most fun RC flyer I’ve ever used. It’s
similar to flying a RC plane, only it’s slower and will glide instead of
dropping if you cut the throttle, so for me it’s a lot less panicky.

[https://bionicbird.com/usa/product/metafly](https://bionicbird.com/usa/product/metafly)

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dmitrygr
All planes (RC and real) will glide if you chop the power. none of them just
fall.

source: am pilot (real and RC)

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filoeleven
Fair enough. Perhaps the higher reaction times needed for RC planes in general
along with the several years that have passed since I last flew one have
clouded my memory. I had lots of fun with the plane too, don’t get me wrong!
The MetaFly is just more my speed, I guess.

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ajuc
If owl wings are more like plane than like other birds' wings (because they
keep feathers together more) - then maybe planes already have these advantages
built-in?

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intellectronica
the owls are not what they seem

