Hello Heather,
Sure, feel free to share that wherever you want. 🙂
Mark
Ar Luan 29 Iúil 2024 ag 07:04, scríobh Heather Gervais <
hmg98103 at gmail.com>:
>
Oh wow, Mark. Thank you very much for that in-depth description. I didn't
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know any of it and found it extremely interesting. I'm in awe.
>
>
A little while back I started a Facebook group - Fun Facts About Birds!
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(North America) - where I'd really love to share a short summary of the
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knowledge you just gave us. Would you be okay with me doing that? I think
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folks in the group would find their jaws dropped just like it did.
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If anyone here would like to join the group and share tidbits they've
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learned about their favorite species, I would love to have you. Since
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starting the group last year, I'm really the only one who's been sharing
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factoids. I'm a bird 'lay person' like all the other folks in the group,
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but with a little help from Google (a lot of help, lol), I've managed to
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share - and learn - a decent measure of information. It would be really
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exciting to get other bird-passionate lay people like me as well as experts
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in the group.
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Peace and happy birding to you Mark, and to you all.
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>
Cheers,
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Heather
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Heather Gervais
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Certified Personal Trainer
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Fitness Instructor
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Spanish Interpreter
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Good person
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>
"Be the change you wish to see in the world."
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- Mahatma Gandhi
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>
Message sent from my iPhone. Please excuse its brevity and occasional
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typos.
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>
>
On Jul 29, 2024, at 3:51 AM, Mark Walton via Tweeters <
>
tweeters at u.washington.edu> wrote:
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>
>
I'm a neuroscientist and my research interests involve how the brain
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controls eye and head movements so this is getting close to my area of
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study. The ability to hold the head steady in space, even while the body
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is moving, is referred to as the vestibulocollic reflex. Basically, the
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organs of the inner ear (the otoliths and semicircular canals) detect head
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acceleration. The brain then sends a copy of this head acceleration signal
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to the neck muscles, which causes them to make an equal and opposite head
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movement. This effectively cancels out any short-duration unplanned
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movement of the head in space. If the head movement was intentional, the
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brain sends a copy of that voluntary movement command to the brain areas
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responsible for the vestibulocollic reflex, so that the reflex can be
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temporarily cancelled.
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>
This reflex is one of several "gaze stabilization reflexes". To understand
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why these are necessary, think about the times when you've seen a news
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camera operator running after the action, while still filming. The camera
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is moving all over the place while the person runs, and you can't see much
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of anything. This is what would happen to our vision without these gaze
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stabilization reflexes. In graduate school, one of my professors told of a
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man who had suffered brain damage that wiped out one of these reflexes
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(vestibulo-ocular reflex, which causes the eyes to rotate in the opposite
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direction from an unplanned head movement). The man could not even read a
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book without wedging his head into a corner of the bedroom, because even
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the tiny head movements that we constantly make were enough to make his
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vision too "jiggly" to read. The vestibulocollic reflex, and the
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vestibulo-ocular reflex, are the reason that you don't become functionally
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blind while you're dancing.
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So many species, including humans, have this same vestibulocollic reflex,
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to stabilize the head position in space during movement. Obviously, this
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gaze stabilization is even more crucial if you're a bird perched on a
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moving branch, or making a sharp turn in flight. So, not surprisingly, the
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vestibulocollic reflex is extremely strong in birds. Another reason that it
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is so strong in birds is that they have a much smaller range of eye
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movements than humans do, which means they have to rely more heavily on the
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vestibulocollic reflex, and less on the vestibulo-ocular reflex.
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>
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Mark Walton
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>
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Ar Sath 27 Iúil 2024 ag 16:44, scríobh Dennis Paulson via Tweeters <
>
tweeters at u.washington.edu>:
>
>>
Jim, it seems to me that birds are able to do that, hold their heads
>>
steady as they move their bodies in different positions. That long,
>>
flexible neck facilitates that greatly. Watch a coot or pigeon moving and
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note their bobbing head. They are holding their head still, presumably for
>>
better vision, as the body moves under it.
>>
>>
Dennis Paulson
>>
Seattle
>>
>>
> On Jul 27, 2024, at 12:41 PM, Jim Betz via Tweeters <
>>
tweeters at u.washington.edu> wrote:
>>
>
>>
> Hi,
>>
>
>>
> I've gone to Channel Drive (near La Conner) several times this week.
>>
I was attempting to
>>
>
>>
> get a picture of a swallow in flight and although a barely useful image
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it does show
>>
>
>>
> something I didn't know about. The swallow was making one of those
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tight, horizontal
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>
>>
> turns. The wings, tail, and body were all turned almost 90 degrees
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(think "vertical").
>>
>
>>
> But the HEAD was still locked in the normal/horizontal orientation.
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A subsequent
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>
>>
> photo of a flock of Western Sandpipers showed the same thing. Perhaps
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this is a
>>
>
>>
> common bird behavior that I just haven't noticed before?
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Fun!!! - Jim
>>
>
>>
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>>
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>>
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>>
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