A retina built for distance
The human eye has one fovea, a small pit at the centre of the retina where photoreceptor cells are densest and vision is sharpest. Eagles have two. The first fovea handles straight-ahead vision. The second, angled at roughly 45 degrees toward the beak, gives the bird a second high-resolution channel for objects off to the side and below, precisely where prey on the ground appears during a soaring pass.
