How can birds safely sit on power lines?

We all know that the electricity in the regular outlets of our homes easily enough to be fatal. Yet, birds have no problem sitting on power lines that carry electricity at a 1000 times higher voltages. How is this possible?

Firstly, this is difficult topic to explain. Personally, I only really understood it two years into my electrical automation engineering studies, so if you don't have a solid understanding of how electricity works, try not to rush through this post and take your time instead. I'll do my best to explain everything in layman's terms.

Electric current describes the amount of electrons flowing through a point in space. If you compare electricity to a river, electric current is like the water current or, in other words, the speed of the flowing water.

When we want to move electrons, we need a path from high potential to low potential. This potential difference is called voltage. If we use the river analogy again, voltage is like the height difference between an upper and lower reach of the river. The higher the upper reach is compared to the lower reach, the more water flows. Similarly, a higher voltage, will cause a higher electric current.

Now, it's important to realize that high potential alone doesn't make electrons move. If there's a dam in a river, water won't flow no matter how high the water level is. Just like water in a river, electricity needs a path to flow through.

When a bird sits on a power line, its entire body is in the same, very high potential as the power line. However, since the bird doesn't touch anything else, the electricity doesn't have a path to a lower potential through the bird, so the bird is fine. If the bird were able to connect two separate lines, or a line and the ground, with its body, the electricity would flow through its body which would probably instantly vaporize.

That's why birds can safely sit on power lines. If I failed to explain this topic clear enough, don't hesitate to send me a follow up question on social media.