It’s so common, in fact, that you’ve probably come to believe that birds are somehow immune to deadly voltage. After all, these are the same power lines that you would never dream of touching yourself!
Perhaps you assume these lines are not carrying power, but are cable lines (or telephone lines for those of us over 40). While it’s true that some of these lines are anything but power lines, how would birds then discern which were safe and which were not? Obviously, this is a dilemma an animal with a “bird-brain” could never figure out. Sorry birds!
So how is it possible for birds to survive something that we know to be mortally dangerous to humans? Do birds possess some type of electro-immunity? The answer is fairly simple and brings us to some of the most basic concepts of electricity.
Let’s look closely at what these power lines are, and how electricity flows through them. There are two basic types of power lines that are commonly commandeered by our feathery friends. The first is primary lines, the second, unsurprisingly, are secondary lines.
Primary Lines are not generally insulated so great care is used to ensure they have been properly spaced apart so as not to allow hundreds of thousands of volts to arc with each other. When lounging on these larger lines, birds rarely have the body size required to reach across the lines with opposing feet. In the rare case that it does happen (and it has!), these poor flyers have certainly cooked their own goose. Sorry birds!
Secondary lines on the other hand, which carry far less voltage (usually only hundreds of volts) are generally insulated. This is why these line pairs are quite often twisted together. It’s an important note that the reduced voltage alone, in no way lessens the risk. Being insulated solves most of the risk facing small feet walking along the wires, but there is also the basic fact that electric currents follow the past of least resistance. Tiny feet clutching the lines are much less conductive than the metal line itself.