You must have observed that birds sit on electric wire unharmed while if the humans touch the same wire they are electrocuted. But if you assume that this is because of some special feature of birds, its time to change the perception. Lets find out the reason why birds can sit safely on a non-insulated high voltage wire.
Electric current is movement of electrons or electric charge which is directly proportional to the potential difference between two points. So more the potential difference greater is the electric charge. The basic requirement for the flow of current is that there must be closed electric circuit. Until and unless the circuit is complete the electric charge won’t flow.
Birds sit on electric wire unharmed because as they sit with both leg on the single wire the circuit is not completed which defies the basic requirement for current to flow. Also, since the bird is on a single wire , there isn’t any potential difference hence no current flows. For the current to flow , bird has to touch other wire while sitting on one. As soon as it happens there would be some potential difference which would cause the charge to flow and bird would be electrocuted.
Sometimes, we do see that the birds get electric shock while sitting on wire and die due to it. The reason behind this is that some birds are too big to have both legs on single wire , as soon as they sit on two different wires there is a potential difference which cause current to flow and birds get shocked.So next time whenever you see a bird sitting comfortably on a wire , don’t be amazed , there’s physics behind it.