Why do some animals, especially Birds, move so Robot-like?

Question

Another example other than birds are squirrels, for example. To clarify what I mean: If you make a noise around them, these animals will suddenly, and very quickly, turn their head towards you. Then, after a couple of seconds, they will turn it away again, in the same sudden, unsmooth way. How come they can’t make smooth movements, and instead just move like a robot?

In: 9

Answer 1

I remember learning about this in school, its basically because they cant move their eyeballs like how we can. So any movement of their vision they need to jerk their whole head.