Photo # 3:

Plastic covers put over the insulator and wire are to prevent large birds from landing on the cross arm & accidentally touching the conductors with their wings. They are used a lot in my area (S. W. Utah) because we have a lot of Eagles (Bald and Golden), Turkey vultures, Hawks & Ospreys. Photographed near Yuma, AZ. Another type of device I have seen, but can't find the photo of, is a triangle made of PVC pipe that clips on to the cross arm.

Miles McLall O-B Miles