I was out walking and saw these strange looking spirals on some power lines.
When I got home I did some research and discovered that they are to prevent birds form hitting the power lines, mainly used in conservation areas. I found this interesting study about which types of flight diverter are the most effective at preventing bird collisions. It mentions a few other types of diverter (plate, swivel, sphere), but the spiral seems to be the preferred shape to experiment with (big vs small) and the reason for this is not explained.
I can understand that a spiral wire has a good visibility to weight ratio, but is this the only reason for the shape? Would there be any current transmitted through (or induced in) the spiral, and would this shape help in any way to prevent any negative effects this might have? Or am I just thinking that there is an electrical reason because the spirals remind me of magnetic field lines, when really that's nothing to do with it?