birdsoup

I have read stories of eagles, particularly in the open spaces of the mountain west, being killed by flying into power lines.  But if eagles have such wonderful vision, why don’t they see the power lines and avoid them?

The explanation is that the power line appears as a pencil thin 2-dimensional line not as a 3-dimensional object.  It is almost like looking thru a picture window than has a single strand of a spider web in one corner.   You never focus on the thin strand.  Instead, you easily disregard it as you gaze at the vast panorama image until it is too late.  In the wide open spaces of the west a tiny line is easily overlooked.