What is this, and how does it help migrating cranes?

This is a bird deflector device (BFD) on a power line for electricity. BFDs help migrating cranes by making power lines more visible so the birds won't collide with them. The BFD is a small spiral device that wraps around the overhead shield wires. This provides a visual image that birds can see. A reflective tag (named Firefly) hangs from the power line. It is visible in low light conditions, the time when collisions are most common. Usually both the BFD and the Firefly are used together at different intervals on the power lines. Flying into hard-to-see power lines is a leading cause of death for migrating Whooping cranes. BFDs will help keep the skies safer for cranes.

Photo: AltaLink

Firefly bird markers- These markers can be seen by birds in low light conditions and reflect both natural and ultraviolet light, allowing birds to adjust their flight path before coming into contact with the line.

Bird flight diverters - These markers increase the diameter of the power line, making it easier for birds to see and avoid the lines.