2008

Distribution power lines are placed high overhead, safely out of human reach; however, for birds, these overhead wires are a potentially fatal obstacle. Under low visibility conditions, birds may fly into power lines. This study's primary goal was to determine how to reduce avian collisions with distribution power lines. A bird flight diverter designed to increase power line visibility was tested to determine its effectiveness for reducing avian collisions with a distribution power line. The 5.6_kilometer, 12_kilovolt distribution power line was equipped with diverters on five sections, systematically interspersed with five control sections and nine buffer spans (the distance between two power poles). Each of the treatment and control sections was made up of four continuous spans. The researchers compared the number of carcasses found below treatment, buffer, and control power lines with a block analysis of variance. Researchers also studied whether changes in avian flight behaviors were an adequate measure of diverter effectiveness for reducing avian collisions. The study found a 60 percent reduction in the number of fatalities under the treated power lines. However, avian flight height and reaction distance were not significantly different between treatments, suggesting that bird flight behavior alone may not be a sufficient method for testing diverter effectiveness. Based on these results, researchers made study design and protocol recommendations specific to distribution power lines; identified data necessary to increase precision of future avian mortality estimates; and discussed land management recommendations that could help to reduce avian collisions with power lines.