If you touch a current carrying wire you get a shock, but if on the same wire a bird sits it does not get any shock. Explain why?

Hint: Know the difference, what happens when an electric circuit is open and closed. It is easy to understand why really humans get an electric shock in the first place when we touch the wire. Apply the same logic to birds and conclude the answer.

Complete Step By Step Solution
A current flows inside the circuit, when the whole circuit is complete. So, when a human touches the wire, uncut and has the source on, he or she feels a shock on his body, since the current flows through his/her body.
This is because, human feet touch on the ground, thus creating a contact with earth. In any circuit, if an earth connection is provided along with the main circuit, the circuit will be complete, which forces the circuit to send all the charges to the ground.
This is not the same case as the bird. The bird will sit on the current flowing wire, which is adrift off the ground by a large distance. Both the padded feet of the birds are on the same wire, where it doesn’t create any contact with the ground, rather it creates air. This means that the circuit is very much incomplete and there won’t be any current flowing on the bird.
Hence, the bird won’t get any shock on its body, due to absence of ground point and incomplete circuit.

Note
In general electrical terms, a circuit is said to be complete, when the electric current starts its flow from the battery to the component and flows back to the battery or gets grounded via neutral wire or ground contact. Grounding doesn’t mean that the circuit is insulated, it is used to release excess amounts of charges flowing in the circuit.