What does it mean when scientists say “an eagle can see a rabbit in a field from a mile away”. Is their vision automatically more zoomed in? Do they have better than 20/20 vision? Is their vision just clearer?

Question

What does it mean when scientists say “an eagle can see a rabbit in a field from a mile away”. Is their vision automatically more zoomed in? Do they have better than 20/20 vision? Is their vision just clearer?

In: Biology

Answer 1

And movement of the ciliary muscles contracting and dilating the pupil are not involuntary like in mammals. As a vet: I can shine a light into their eye trying to check response to light and the birds go “no, dunno if I feel like it”.