Science Journal

Why Don't Birds Get Electrocuted on Power Lines?

While we were walking on a street, the person I admired looked at the birds perching on the power lines and wondered why those small brown birds do not get zapped. I told her that the powerlines they are sitting on were coated with plastic, therefore it is insulated which prevents those adorable birds to become a fried chicken. But she retorted that those powerlines we were looking were not insulated but rather purely made out of metal. So, I shrugged and told her it is probably their feet that are made of plastic.

So when I went home, I directly googled about it. Though I know the definition of electric current, which is a movement of electrons. What I do not know was that it moves from lower potential to higher potential creating a circuit. If someone gets electrocuted, the electrons travel through their body to go to a place with higher potential, usually the ground. So, birds on overhead power lines do not feel any current flowing through their body because both feet are on the same wire. They were not in contact with a spot of higher potential, like the ground. Another way of saying is, they do not complete the circuit. If a circuit is incomplete, no electrocution happened.

But since I first encountered the words lower and higher potential, I searched about their meaning. High potential consists of positive charges whereas low potential is an area for negative charges. Since the electrons are negative charge and attracted to positive charges, they will tend to move from low potential to a higher potential where their opposite charge is. Thereby creating a circuit or a current.

However, there are some birds that are being electrocuted. Usually, the big birds or raptors like eagle, hawks, and owls. Since they are massive and when they rest on the live wire (which carries electric current to the appliances) and when they tried to stretch their wings and inadvertently touched the neutral wire (carry the return current from the load back to the energy supply) or ground wire (provides conducting path to the earth), a circuit will occur. They turn into a roasted food instantly. Lucky for those people who witnessed those events because they could save some money by bringing that free food home. 

Anyway, sadly, I could not tell her what I've learned because I do not know how I will open that kind of topic and I'm shy to have a conversation with her.