why do pigeons cock their heads back and forth when they walk?

Answer 1

Mindoversplatter is correct. They are watching for predators though probably not the ground or a specific fixed object.

Here we see a superb aerial acrobat that is on the ground and almost helpless until it makes the air again. To compensate they are watching constantly for predators. Their eyes are focused on everything around them at once. Scanning the area for anything posing a threat.

Now imagine yourself in a rotating chair and trying this. You would instinctively fix your eyes on one point, rotate a little and then refocus on another point. The pigeon is doing the same thing only as I said is probably not actually focusing on one point. The pigeon is moving its neck instead of its eyes as that will allow it to continue to scan everything.

BTW pigeons like virtually all birds have excellant stereoscopic vision since their eyes are on the side of their head in such a location that they can both see forward. Without this ability the bird could miss a branch or limb while flying and become seriously injured because of misjudged distance.

Answer 2

I'm a pigeon keeper and biologist and I don't really know but I'll take a shot at this. I've seen pigeons watching turntables and their heads go in little circles as they focus on a point and follow it. Rather than their eyes moving in their heads as ours do they move their whole head to keep sight of a point. I suspect that something similar is going on as they walk. They have a visual focus point and as their walk moves the head forward they compensate with the back and forth movement of their heads to keep it in focus.

Answer 3

They don't have stereoscopic vision because their eyes are on opposite sides of their heads, and the areas seen by the 2 eyes don't overlap. They move their heads around to compensate for this by getting a variety of overlapping perspectives on their surroundings. The pigeon's brain puts these together to make a coherent picture, just as a human's brain takes the 2 perspectives from the 2 eyes and melds them into a 3D picture. Birds need to have a good sense of perspective and depth, because they fly in 3 dimensions. [Dogs, on the other hand, seem to see in 2 dimensions; their senses of hearing, smell, and touch enable them to enrich their perception of their surroundings.]

Answer 4

Well I could type out a long explanation, but why do that when I found a website that can do it for me?
Go down to the 7th answer I believe, made by Criss, and read what he said.
http://www.thenakedscientists.com/forum/index.php?topic=1144

Hope that helped ^_^
- Becky