h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Why do birds nod their heads when they walk?

It has to do with the way birds vision works. They bob their heads as they walk to stabilize their image of the world temporarily, otherwise it would all be a blur. Humans and other animals do something similar by twitching our eyes.

http://www.wired.com/2015/01/whats-birds-bob-heads-walk/

Ach so! And I thought it might be something to to do with their anatomy. Well you learn something every day and at my age, forget it by the next morning

...much the same thing as makes men swing their shoulders and women swing their hips when walking, balance...

I wouldn't know anything about that, I'm totally unbalanced according to my psychiatrist. Actually, no joke, my balance is going - its all these cochlear hairs dropping off inside and my other hair dropping off outside

It's not for balance, as they tested birds on treadmills inside clear boxes and when they walked while their environment was stable they didn't bob their heads.

Also see this related video.

http://youtu.be/_dPlkFPowCc


He later attaches a minicam to a chicken's head to see if it would make a good steadicam.

Extremely interesting but I must dash - visiting the doctors for 3.00 appointment

Wynken, Blynken, and Nod one night
Sailed off in a wooden shoe,—
Sailed on a river of crystal light
Into a sea of dew.

Did it work Baron? I was thinking of when the chicken crossed the road, on the way to the slaughterhouse

I thought it was a pea green boot, not a shoe?

Still its probably on the other foot now

The peas in my garden are starring in a podcast.

Did the Chickicam work? Well, sort of.

http://youtu.be/UytSNlHw8J8

But not really. When the chicken holds its head still, you get a still image, but you don't really get much choice about where the camera points and how long it points there.

Not really a chicken-eye point of view, the chickens eyes point out the sides of its head, hence constant head motion as it watches all around.

I expect that many fish have a similar problem with seeing.