Bird song sonographs show distinct drawing patterns • Hacker News Board

Re: Bird song sonographs show distinct drawing patterns

#21

Post by jcims » Fri, May 07, 2021, 4:34 PM UTC

morelisp wrote: post #16

jcims wrote: post #14

Earlier quoted context omitted.

This is my laymans test for the FFT theory. Put in earbuds or a headset and (quietly) play sounds that are slightly different in frequency (1-10hz). You will still hear a sort of ethereal beat tone between them that's different than the beat you would hear if you were listening to the same through speakers. I don't see how this would occur frequency-domain perception and it's too present (at least in my experiment) t…

https://en.wikipedia.org/wiki/Beat_(acoustics)#Binaural_beat...

Whoa! At least that gives me some comfort I wasn't imagining it.

I wish I understood some of the neurological explanation of how the beats are perceived because it doesn't seem to match with my understanding of the explanation of how our ears work. If everything is pushed into the frequency domain based on the stimulation of different parts of the cochlea, where does the time domain beat emerge?

Re: Bird song sonographs show distinct drawing patterns

#22

Post by Xophmeister » Fri, May 07, 2021, 4:37 PM UTC

usrbin wrote: post #13

wombatmobile wrote: post #11

Um, I'd like to be able to parse this article. but I don't know what it is saying. Can anyone explain the gist of it to me in simple terms? What does this mean? "These sonograms are remarkably different from other sounds, as if birds “draw” with sound something that’s flying backwards in time."

Audio person here. I found the post fascinating, but I wish they did more to explain what they were talking about to a layperson. Basically, all sounds that you hear are composed of many layered sine waves of different frequencies and intensities. The graphs in the post are spectrograms, which graph those frequencies over time. The Y axis represents pitch, the X axis represents time, and the brightness at any given p…

So this would be a good example of a pure(ish) sine wave produced naturally, albeit modulating pitch over time? That's pretty rare, I believe.

Re: Bird song sonographs show distinct drawing patterns

#23

Post by mattkrause » Fri, May 07, 2021, 4:48 PM UTC

kurthr wrote: post #12

throwamon wrote: post #7

For a moment I thought they would hypothesize that the patterns might be an actual “rendering” of what the birds were looking at, especially when I saw the 7th image which looks remarkably similar to a rodent. Apparently I'm pretty far off, but just this idea of animals communicating images with sound waves was something I'd otherwise never have.

What if groups/species of birds had "collective synesthesia"? Some people see colors or feel tastes... and it doesn't seem that unlikely that there would be selection pressure for parts of the bird brain to connect their spatial awareness to their auditory system and then songs. There could be a nice feedback loop that their own songs would strike similar experiences for themselves (if they hear themselves similar to…

They kinda do!

If you place migratory birds in a big round cage, they show 'Zugunruhe[0]', or migratory restlessness: they jump and flutter in the direction that they would be otherwise be migrating if they were out in the wild. Rotating the magnetic field (e.g., by putting magnets around the aviary) also rotates the direction of their Zugunruhe.

No one totally understands how this works, but the magnetic information is thought to be 'overlaid' on other sensory information. One candidate pathway involves a light-dependent pathway in the retina. When a cryptochrome absorbs light, it generates radical pairs that affect how visual information is perceived[1]. This could give the birds something like HUD which displays magnetic field lines on top of the visual scene. Consistent with this idea, birds can only orient to magnetic fields under certain colors of light, with the color varying a bit from bird to bird[2]. It's almost as if the colored light washes out the HUD.

There's another parallel pathway involving bits of magnetite in the beak[3,4]. These signals flow through the trigeminal nerve, which carries a lot of different signals; it would not be impossible for this to manifest as "pressure", as it carries touch/somatosensory information in many animals.

[0] Ethologists love German and this word captures my lockdown feeling so very well. [1] https://www.sciencedirect.com/science/article/pii/S000634950... [2] https://www.nature.com/articles/364525a0 [3] https://www.sciencedirect.com/science/article/pii/S000634950... [4] https://royalsocietypublishing.org/doi/10.1098/rspb.2009.005...

Re: Bird song sonographs show distinct drawing patterns

#24

Post by klyrs » Fri, May 07, 2021, 4:52 PM UTC

usrbin wrote: post #13

wombatmobile wrote: post #11

Um, I'd like to be able to parse this article. but I don't know what it is saying. Can anyone explain the gist of it to me in simple terms? What does this mean? "These sonograms are remarkably different from other sounds, as if birds “draw” with sound something that’s flying backwards in time."

Audio person here. I found the post fascinating, but I wish they did more to explain what they were talking about to a layperson. Basically, all sounds that you hear are composed of many layered sine waves of different frequencies and intensities. The graphs in the post are spectrograms, which graph those frequencies over time. The Y axis represents pitch, the X axis represents time, and the brightness at any given p…

That's really interesting... I wonder if it has something to do with birds have such small resonating chambers, so I looked for bigger birds. Apparently, emus make several calls that have interesting harmonics.

https://www.xeno-canto.org/species/Dromaius-novaehollandiae?...

Re: Bird song sonographs show distinct drawing patterns

#25

Post by temporalparts » Fri, May 07, 2021, 5:03 PM UTC

Slight related tangent: For all those interested in birding, I highly recommend the BirdNet app available on Android and iOS! You can record and send audio data, and it will try to classify the bird for you based on the recording.

In the process of recording, it will show you the bird's spectrograms, which is really cool!

Re: Bird song sonographs show distinct drawing patterns

#26

Post by plutonorm » Fri, May 07, 2021, 5:06 PM UTC

akomtu wrote: post #18

kurthr wrote: post #12

Earlier quoted context omitted.

What if groups/species of birds had "collective synesthesia"? Some people see colors or feel tastes... and it doesn't seem that unlikely that there would be selection pressure for parts of the bird brain to connect their spatial awareness to their auditory system and then songs. There could be a nice feedback loop that their own songs would strike similar experiences for themselves (if they hear themselves similar to…

I remember that "cymascope" experiment that used a dolphin's sound as input. Turned out the water surface had an image (after lots of noise deblurring) of a human the dolphin just seen. This means the organ that decodes sound is a simple membrane with water. How dolphins encode images into sound is a separate question.

I don't remember this but would extremely interested to see it. Any link?

Re: Bird song sonographs show distinct drawing patterns

#27

Post by topspin » Fri, May 07, 2021, 5:10 PM UTC

It makes sense to me that bird song would have few harmonics. Although we may appreciate the beauty of bird song they don't sing for aesthetics. They are signaling. Concentrating energy into a narrow band delivers greater range for the same energy than harmonically rich signals. We do likewise with electromagnetic communication.

Re: Bird song sonographs show distinct drawing patterns

#28

Post by noxToken » Fri, May 07, 2021, 5:13 PM UTC

wombatmobile wrote: post #11

Um, I'd like to be able to parse this article. but I don't know what it is saying. Can anyone explain the gist of it to me in simple terms? What does this mean? "These sonograms are remarkably different from other sounds, as if birds “draw” with sound something that’s flying backwards in time."

Andrew Huang does a good job of explaining harmonics and overtones[0]. You only need to watch until about the 4 minute mark (from the timestamp) to get an explanation of harmonics and what the sonograms represent.

The short of it is that most natural sounds product a root tone plus a varying amount of related tones above it. Our ears hear the root tone, and the other tones above it are what give the sound its uniqueness. That's why a guitar, a clarinet and 3 singers can produce the same note while sounding distinct.

Birds seem to produce a natural sound without a lot of the related tones above it. Their sound is, relatively speaking, much purer than most other natural sounds. That's very unique.

[0]: https://youtu.be/Wx_kugSemfY?t=95

Re: Bird song sonographs show distinct drawing patterns

#29

Post by algui91 » Fri, May 07, 2021, 5:15 PM UTC

temporalparts wrote: post #25

Slight related tangent: For all those interested in birding, I highly recommend the BirdNet app available on Android and iOS! You can record and send audio data, and it will try to classify the bird for you based on the recording. In the process of recording, it will show you the bird's spectrograms, which is really cool!

That’s really cool! trying it out now. thanks for the recommendation.

Re: Bird song sonographs show distinct drawing patterns

#30

Post by periheli0n » Fri, May 07, 2021, 5:32 PM UTC

topspin wrote: post #27

It makes sense to me that bird song would have few harmonics. Although we may appreciate the beauty of bird song they don't sing for aesthetics. They are signaling. Concentrating energy into a narrow band delivers greater range for the same energy than harmonically rich signals. We do likewise with electromagnetic communication.

When a bird sings to attract a mating partner, competing against other birds, does it not sing for aesthetics?

Also, couldn’t harmonics be used to improve decoding in noisy environments? Spreading the signal over a wide band is not unheard of in man-made electromagnetic communication either.