Just because people are corporeal born to this world doesn't mean that they understand everything about it, similarly just because somebody's died doesn't mean that they understand everything about the incorporeal world
A creepy cry that sounds like a human voice, velvet black wings, the image of tearing into dead flesh; crows are known across the world as an ill-omened bird that flies down with ill-luck
We experience and understand the world through signals that are received by the senses and interpreted by the brain - and both stages are subject to distortion