Why Do Birds Perch on Overhead Power Lines Without Experiencing Electric Shock?
Birds can safely perch on a single energized overhead conductor because both feet are at nearly the same electrical potential. Therefore, there is negligible potential difference across their bodies, resulting in insignificant current flow.
However, a human touching an energized conductor while standing on the ground may create a current path between the high-voltage conductor and earth. The resulting potential difference can drive dangerous electric current through the body, causing electric shock or electrocution.
Electric shock occurs when a potential difference drives current through the human body.