Give Now  »

Noon Edition

Why Aren't Bird Electrocuted When They Perch On Power Lines?

It's not unusual to see lines of birds perched on power lines. But did you ever wonder why birds aren't electrocuted by the currents that flow through these high-voltage wires?

You might think it's because the wires are insulated, but they're actually not insulated at all that's why downed power lines are so dangerous. No, the only reason why birds on power lines usually aren't electrocuted is because the wire is the only thing they're touching!

Why No Zap?

Like all energy, electricity seeks equilibrium, or balance. That means electricity will flow from high-energy areas to areas of less energy, always using the path of least resistance. So if the bird has one foot on our original wire, and the other foot on, for example, the ground or on a different wire with less voltage, the bird would be electrocuted. The electricity would pass through the bird on its way from the high-voltage line to the lower-voltage line or the ground.

But as long as both of the bird's feet are on the same wire (or wires of the same voltage), the bird is safe. The current doesn't have anywhere else to go, so the electricity won't pass through the birdit stays on the path of least resistance, the wire.

Don't Try This At Home!

This would work for humans, tooif you were to hang suspended from one of these wires, you wouldn't be electrocuted, as long as you didn't get too close to anything else, like a telephone pole or the ground. But don't try this experiment at home! If you want proof, just look up at the birds on the wires!

Support For Indiana Public Media Comes From

About A Moment of Science