It was a windy day and this eagle picked a strong limb for a perch to look over the territory. Eagles are known for their keen eyesight and an eagle's eye is almost as large as a human's, but its sharpness is at least four times that of a person with perfect vision. The eagle can probably identify a rabbit moving almost a mile away. That means that an eagle flying at an altitude of 1000 feet over open country could spot prey over an area of almost 3 square miles from a fixed position.