Earth Notes: Raptor-Friendly Power Poles

Aug 21, 2019

Millions of birds are killed every year by electrical power lines—especially in the wide-open country of the Colorado Plateau where power lines and poles are often all that’s available for birds to nest and roost on.

Hawk on retrofitted pole
Credit Wade Ward, APS

Golden eagles and ferruginous hawks are especially likely to be electrocuted—most often on medium-voltage lines where the conductors are spaced close enough to be bridged by the large wingspan of these raptors.

If a bird touches two parts of energized transmission equipment, an electrical circuit is completed, and the current passing through the bird kills it.

The best fix is to build bird-friendly power lines and poles from the get-go. Transmission lines ideally need to be spaced at least 60 inches apart and 60 inches above the ground—to accommodate the height and wingspan of eagles and big hawks. Existing poles can be retrofitted with longer crossarms to provide that safe degree of separation, and many utilities are undertaking this fix.  

Insulating live parts of transformers also prevents lethal contact—not just for the largest raptors but also for perching owls and smaller birds that may try to nest there.

Then there’s location. In zones with high risk of collision, relocating or burying power lines is best. But if that’s too expensive, marking the lines to make them more visible to birds can help. 

Colored balls, swinging markers, or triangular pieces of plastic on power lines and poles are installed to prevent avian collisions and electrocutions—helping save some of these majestic birds from an untimely death.