What is the function of the rotating wind speed dial on the high-voltage power line tower?

What is the function of the rotating wind speed dial on the high-voltage power line tower?

It is used to drive away birds and prevent them from nesting on high-pressure towers.

There are two hidden dangers after nesting:

1, birds often walk, and bird droppings easily fall on the insulation, causing surface pollution and insulation damage;

2. The nesting materials of birds are generally branches, and rainy weather will cause thermal insulation damage.