A Bald Eagle keeping watch over the Puget Sound. Taken from Alki Beach, Seattle, Washington.
All eagles are renowned for their excellent eyesight, and the bald eagle is no exception. They have two foveae or centers of focus, that allow the birds to see both forward and to the side at the same time. Bald eagles are capable of seeing fish in the water from several hundred feet above, while soaring, gliding or in flapping flight. This is quite an extraordinary feat, since most fish are counter-shaded, meaning they are darker on top and thus harder to see from above. Eagles, like all birds, have color vision. 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.
Information from baldeagleinfo.com
Canon 50D, EF100-400mm at 400, F6.3, 1/400, ISO 100