On high-voltage power lines, it’s not uncommon to spot flocks of small or large birds seemingly taking a break. But why do they do this, and how do they avoid being electrocuted? The first question is relatively easy to answer. The wires provide a convenient perch from which birds can survey their surroundings for potential predators or prey. Plus, trees don’t obstruct their view. But how do they manage to stay safe? In reality, many of these birds do fall victim to electrical currents. According to a 2014 study, between 0.9 and 11.6 million birds die from electrocution in the U.S. each year. Larger birds, such as raptors, face a particularly high risk. They are more likely to touch two wires at once or simultaneously contact a wire and a grounded source, as reported by IFLScience.
Meanwhile, a 2016 study conducted by the National Wildlife Forensics Laboratory of the U.S. Fish and Wildlife Service examined 417 raptors that had died from electrocution. Experts found that about 80 percent of the deceased birds were either bald eagles or golden eagles.
So, why do some birds manage to survive? The reason some birds don’t get electrocuted likely lies in their ability to perch correctly on power lines. These individuals can settle on a single wire without harm, as long as they remain ungrounded. “Birds do not create a connection between the power line and the ground, so they do not complete the circuit,” explained Will Babb from the Ohio Department of Natural Resources’ wildlife division. However, if they were to touch the power line while standing on the ground—an unlikely scenario—they would complete the circuit and meet their demise. A grounded, conductive object that touches an energized wire is a deadly trap for birds. Therefore, if a bird, for instance, touches both a wire and a pole at the same time, it will inevitably perish. Similarly, if a bird simultaneously contacts two high-voltage power lines, the outcome will be just as tragic.