The Genius of the Barn Owl's Feathers
thereader.mitpress.mit.eduWhat isn't mentioned is that owl feathers are generally less oily than many other birds. This makes them softer and thus quieter, but the penalty is that that they get water-logged faster. As a result, owls find it harder to hunt in wet weather, and extended rainy periods can cause real problems, especially in the breeding season, when youngsters need continual feeding.
(source: I used to volunteer at a Raptor conservancy).
Adding to this, I highly recommend looking up images of wet owls. They look hilarious.
Yes. Especially for owls like the Great Grey, it shows how small the bird is inside all of those feathers.
Reminded if this video immediately https://youtu.be/-WigEGNnuTE they got almost nothing on the mics.
Look at how pure the signal is from the peregrine's wings. The signal from feral pigeon is extremely noisy in comparison, as if it is fighting to stay the in the air. The peregrine wingbeat is clean so I presume the energy is being turned into velocity with high efficiency. Extremely cool.
I also love the longer clip with the bed of feathers: https://www.youtube.com/watch?v=d_FEaFgJyfA
It gives a good visual as to how much air is being moved/disturbed during the flight/glide of each.
> Over the next few days, the owl makes 16 more strikes at mice, missing only four times, each time by less than two inches.
How did the experimenter measure miss distance in pitch darkness? IR illumination is presumably out in case the owl was able to see it, and I didn't think thermal imaging was a thing yet in the late '50s.
Scratch markings on wax flooring beneath the leaf cover or the grid location on the floor was instrumented to report to telemetry when carrying weight of the owl. Assuming the mouse had its ankle rope tied to a pin nailed into the floor.
He did use a IR stroboscope and a camera, as owls can apparently not see IR.
But in that case this bit of TFA feels a bit out of place:
> To eliminate the possibility that the owl was [...] detecting heat from the body of the mouse (for instance, by sensing infrared light emitted by a warm body), the experiment is repeated with a mouse-sized wad of paper dragged through the leaves
Completely random guess, but perhaps ultrasonically? Ultrasonic rangefinders are relatively cheap and accurate these days, so maybe they were too in the '50s?
It doesn't seem like owls have infrared vision, in that case an IR camera looks like the easiest way to go.
They mention that the ears have gone non-bilateral to achieve better 3d sound localization.
It brings to mind the question of why nothing seems to have evolved two pairs of ears with separate openings; We're all working with varying degrees of spectrum shaping to achieve up-down sound localization. If you wanted to design a robot that can perform sound localization, the obvious answer for that extra dimension would be to just double up on the microphones.
Helpful reframing on this reddit post: https://www.reddit.com/r/answers/comments/mo5sqi/do_any_anim...
What do ears do? Transduce pressure vibrations into intelligible signals. If this is our understanding of an 'ear', we never really need more than two but instead need either binaural or non-binaural/decoupled. Beyond that, what does having more openings grant us that we're not getting with all the other pressure-sensitive organs we have? (namely all of our skin, some specialized tissues in other animals)
Some of the arguments would imply that we should only really have the one ear, since you can do it all with complex spectrum shaping.
But binaural gives us a dramatically easier grasp of left-right localization. For a lot of things, that's all you need!
But the animal kingdom is large and diverse, and high-fidelity up-down-left-right localization would be similarly valuable in numerous places. It is a little bizarre to me that there's no freaky bat or something out there that evolved an extra molar into its own little secondary sonar sensor, with a centimeter of baseline from the normal set. Because with robotic sensors it wouldn't even be a question what to do.
Looking at the Russo/Ukrainian war, I wonder if/when someone introduces "owl drones".
Current drones are not very loud (well, Shaheds are), but if someone could make them more silent, they would be even harder to detect. Maybe covering them with a structure similar to owl featchers would do it.
Zipline has a patent on their quieter drone rotors, based off barn owls, according to Mark Rober.
it's not just the feathers, it's the full systems integration that shows the genius of incrimental evolutionary design.the refinement is so equisite as to suggest an internal feedback mechanism that helps evolutionary processeses do there thing. as a person who designs and builds all sorts of things with integrated systems, all the time, and has a strong interest in aircraft design/engineering this example realy does show genius, and humans cant replicate it. also, crows HATE owls and I have seen them chase and mob owls, hundreds of crows after one owl, they aint called a murder of crows for nothing, have also seen mass airial battles with crows and seagulls, fighting on the wing while circling in a big thermal, again, hundreds of birds on both sides. love owls, and egulls, woodpeckers, most birds, but my strong favorite are chicadees
My 9 yo corrected me the other day. “That’s not a barn owl, it’s a barrad owl.” I had to google it. Apparently they’re both a thing.
> barrad owl
I am not an ornithologist, but I’m assuming that’s a typo for barred owl?
MIT should know better that Natural Selection ≠ Genius
It is a figure of speech. That article is not a scientific article, it is a human-readable popularizing text for non-professionals.
And yet we see a christian posting about "what his father made" in this thread, on hacker news. Figures of speech do matter.