Thank you!
I've reread your email a few times and plan to share it all - every tidbit is SO interesting! And your analogies are great!
Peace, Heather
Heather Gervais
Certified Personal Trainer
Fitness Instructor
Spanish Interpreter
Good person
“Be the change you wish to see in the world.”
- Mahatma Gandhi
Message sent from my iPhone. Please excuse its brevity and occasional typos.
On Jul 29, 2024, at 7:07 AM, Mark Walton wrote:
Hello Heather,
Sure, feel free to share that wherever you want. 🙂
Mark
Oh wow, Mark. Thank you very much for that in-depth description. I didn't 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! (North America) - where I'd really love to share a short summary of the knowledge you just gave us. Would you be okay with me doing that? I think folks in the group would find their jaws dropped just like it did.
If anyone here would like to join the group and share tidbits they've learned about their favorite species, I would love to have you. Since starting the group last year, I'm really the only one who's been sharing factoids. I'm a bird 'lay person' like all the other folks in the group, but with a little help from Google (a lot of help, lol), I've managed to share - and learn - a decent measure of information. It would be really exciting to get other bird-passionate lay people like me as well as experts in the group.
Peace and happy birding to you Mark, and to you all.
Cheers, Heather
Heather Gervais
Certified Personal Trainer
Fitness Instructor
Spanish Interpreter
Good person
“Be the change you wish to see in the world.”
- Mahatma Gandhi
Message sent from my iPhone. Please excuse its brevity and occasional typos.
I'm a neuroscientist and my research interests involve how the brain controls eye and head movements so this is getting close to my area of study. The ability to hold the head steady in space, even while the body is moving, is referred to as the vestibulocollic reflex. Basically, the organs of the inner ear (the otoliths and semicircular canals) detect head acceleration. The brain then sends a copy of this head acceleration signal to the neck muscles, which causes them to make an equal and opposite head movement. This effectively cancels out any short-duration unplanned movement of the head in space. If the head movement was intentional, the brain sends a copy of that voluntary movement command to the brain areas responsible for the vestibulocollic reflex, so that the reflex can be temporarily cancelled.
This reflex is one of several "gaze stabilization reflexes". To understand why these are necessary, think about the times when you've seen a news camera operator running after the action, while still filming. The camera is moving all over the place while the person runs, and you can't see much of anything. This is what would happen to our vision without these gaze stabilization reflexes. In graduate school, one of my professors told of a man who had suffered brain damage that wiped out one of these reflexes (vestibulo-ocular reflex, which causes the eyes to rotate in the opposite direction from an unplanned head movement). The man could not even read a book without wedging his head into a corner of the bedroom, because even the tiny head movements that we constantly make were enough to make his vision too "jiggly" to read. The vestibulocollic reflex, and the vestibulo-ocular reflex, are the reason that you don't become functionally blind while you're dancing.
So many species, including humans, have this same vestibulocollic reflex, to stabilize the head position in space during movement. Obviously, this gaze stabilization is even more crucial if you're a bird perched on a moving branch, or making a sharp turn in flight. So, not surprisingly, the vestibulocollic reflex is extremely strong in birds. Another reason that it is so strong in birds is that they have a much smaller range of eye movements than humans do, which means they have to rely more heavily on the vestibulocollic reflex, and less on the vestibulo-ocular reflex.
Mark Walton
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 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 it does show
>
> something I didn't know about. The swallow was making one of those tight, horizontal
>
> turns. The wings, tail, and body were all turned almost 90 degrees (think "vertical").
>
> But the HEAD was still locked in the normal/horizontal orientation. A subsequent
>
> photo of a flock of Western Sandpipers showed the same thing. Perhaps this is a
>
> common bird behavior that I just haven't noticed before? Fun!!! - Jim
>
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