A chart of power-line temperatures might provide the answer.
We very often see flocks of birds perched in trees, on rooftops, on local power line wires, and even on radio antennas.
Figure 1 Birds often perch on antennas.
However, I have noticed that I never see birds coming to rest on high-tension power lines.
Figure 2 Birds don’t normally come to rest on high tension power lines.
I may have come across the reason on the NKT Photonics site. Please examine Figure 3, which shows power line wire temperature excursions when conditions go from normal service to an emergency.
Figure 3 This chart shows power line temperatures from normal service to emergency conditions.
The vertical axis of this chart shows temperatures as far down as 62°C, but even normal wire service temperatures are shown well above that. This may be normal service but it is HOT stuff.
I discussed in a previous post that biological harm can be incurred at only 50°C, well below the above wire temperatures. It’s no wonder that birds don’t perch on those wires. If I were a bird, you wouldn’t find me up there either.
John Dunn is an electronics consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York University (MSEE).