AERIAL MARKER SPHERES
(AVIATION BALLS)
Aerial marker spheres (or aviation balls) were
one of the earliest devices used in an attempt
to reduce bird collisions (Figure 6.8 and Figure
6.9). Originally they were used to warn
aircraft pilots of power lines. These large,
colored balls are usually attached to distribution
phase conductors or transmission shield
wires. They are available in a variety of diameters:
23 cm (9 in) to 137 cm (54 in). The
most often used sizes for line marking are
23 cm (9 in) and 30.5 cm (12 in).
Aerial marker spheres are available in a
variety of colors, including international
orange, gloss white, or gloss yellow.