These Are For The Birds

13 March 2024

Have you seen coils or fluttering tags on power lines? Not related to power transmission, these accessories are visual cues that alert birds to the presence of wires.

Bird diverters come in many shapes and have changed over the years as new products come to market and are approved by government agencies. California commissioned a 2008 study to evaluate the orange and fluorescent swinging tag below for use in the Sacramento Valley where hundreds of thousands of waterfowl spend the winter.

Aerial marking devices (flight diverters) are intended to reduce avian collisions with power lines by increasing power line visibility. From Testing the Effectiveness of an Avian Flight Diverter for Reducing Avian Collisions with Distribution Power Lines in the Sacramento Valley Published 2008

This (newer than 2008) model from Power Sentry glows in the dark and is visible in fog.

Hawk Eye Bird Flight diverter (photo embedded from
(video embedded from PowerLineSentry on YouTube)

It is also less expensive to install because it can be done by drones.

(video embedded from Manitoba Hydro on YouTube)

Those devices are for the birds.

These are for pilots.

Red ball markers make power lines visible to airplane and helicopter pilots and are usually installed near airports and on long lines over rivers and canyons.

Aviation red ball marker on power line. The helicopter is probably so close because it’s checking the power lines (photo from Wikimedia Commons)

Ironically, they have to be installed from helicopters. This 6-minute video filmed in West Virginia shows a job I could never do.

(video embedded from T&D World on YouTube)

Wondering about cones? They are also visual cues for pilots.

Power line cone to alert pilots (photo from Wikimedia Commons)

p.s. Some of you know more about this than I do. If I got it wrong, please leave a comment.

(credits are in the captions)

2 thoughts on “These Are For The Birds

  1. oh my goodness, so many things explained. Reading your blog daily provides answers to questions i have had forever. Thank you.

  2. Whoa! What an amazing video. Never thought about how these markers get placed on transmission lines. These workers must not have a fear of heights. They should be paid a great salary to do this job. Thanks for showing us how this is done.

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