Have you ever looked closely at a birds eyes? Many birds, including many in the Rocky Mountains, are not able to move their eyes around without moving their head.
If you look closely at a bird the next time you are out and about you may notice something. Birds eyes do not have the white surrounding the pupil like humans eyes do. This is because most birds eyes are fixed in their head and can’t move around. This causes the birds to move their heads, necks, and bodies in strange ways.
Birds Vision Is Their Most Important Sense
Birds rely on their vision a lot. In fact, in general birds have much better vision than people. On average a bird has two to three times better vision than people.
Their eyes are large relative to the size of their heads and their bodies. This is because good vision is so important for them to detect food, and avoid predators.
Birds Eyes Are Fixed In Their Head
Yes, as strange as it seems, birds eyes are fixed, fitting tightly into their head. This means that birds can’t simply roll their eyes around in their head to look at something. Instead of holding their head still and moving their eyes around they have to move their entire head. This is why you will often see bird constantly moving its head to one side or the other or bobbing it like a chicken or pigeon does.
If a bird is sitting still and wants to look at something else it needs to turn its head or move it a different direction.
Birds Eyes Are Fixed, So Their Neck Compensates To Hold Vision Steady
If a bird is moving and its wants to keep its eyes looking at something while it is moving then its body must compensate.
This sounds confusing, but is actually pretty simple. If a bird is moving, say walking or flying, it can keep watching one spot. It is able to do this because the birds neck and body will automatically move and adjust so that the head does not move. This allows the bird to focus on that spot for a moment. Then the head can move and it will focus on a different spot.
There are some good Youtube videos that show how this works.