
After Tens of Thousands of Pigeons Vanish, One Comes Back - srikar
http://phenomena.nationalgeographic.com/2016/05/26/after-tens-of-thousands-of-pigeons-vanish-one-comes-back/
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wnoise
> Mouritsen thinks, that the reason those warblers left Tennessee was not
> because they heard wisps of a distant superstorm but because of changes in
> atmospheric pressure.

Sound _is_ changes in atmospheric pressure, and we're talking about infrasound
which is really low frequency, so there's not exactly a sharp distinction
here.

~~~
ahazred8ta
TLDR - the pigeon problem coincided with high-decibel infrasound from sonic
booms from the Concorde SST. That suggests they were temporarily deafened in
that frequency band. (At 11 octaves below middle C, they're sensitive to
anything over 0.1 Hertz.)

~~~
Dylan16807
Is it actually possible to be specifically deafened at such a low frequency?
There's no resonance down there, and it would be so much lower energy. I would
expect all other hearing to be severely and possibly permanently impacted
before infrasound could be deafened.

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talktime
I'd like something that keeps pigeons off my balcony. Surprisingly little
works. I have a motion detecting sonic alarm that doesn't work - maybe it's in
the wrong frequency for pigeons. I wonder if a motion detecting laser
frightener would work better. Kickstarter anyone?

~~~
bduerst
Have you tried a feline alarm system? Worked for us.

~~~
talktime
Thanks. I'd like to give that a try. Do you have a link to the type of model
that has worked for you?

~~~
bduerst
I'd get one used or second hand, since they tend to be better at detecting the
birds.

~~~
talktime
sure, but 'feline alarm system' is kind of vague - what type or model worked
for you?

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ck2
I've got a feeling in a couple decades the military will declassify how they
used some kind of new ULF device to talk to submarines and it had a power
level equal to nuclear weapons.

And that as a side effect it screwed up all kinds of wildlife.

~~~
vanderZwan
Just plain sonar is bad enough, and that's been public knowledge for a while:

[http://www.scientificamerican.com/article/does-military-
sona...](http://www.scientificamerican.com/article/does-military-sonar-kill/)

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shermablanca
For sure this is interesting, but it's curious that articles of this sort are
appearing on HN with increasing frequency. There used to be purely tech news,
now it seems that anything interesting qualifies for an up vote.

~~~
beardog
"On-Topic: Anything that good hackers would find interesting. That includes
more than hacking and startups. If you had to reduce it to a sentence, the
answer might be: anything that gratifies one's intellectual curiosity."

~~~
lostlogin
A post like the parent and a reply of the guidelines happens multiple times
per weekend. I wonder when the complainers will notice the pattern and accept
it.

~~~
mikekchar
New people come along all the time. I was also confused by the guidelines.
Possibly they need to be in a more prominent place.

