What are those metal coils on the utility wires?

BFD - Bird Fight Deflectors

My drive in to Alma, Wisconsin today was slowed by a bucket truck and a half dozen men working on the utility lines along the Great River Road by Rieck's Lake Park.  They were installing little yellow metal coils. 

"What are those coils for?"  I asked the man in charge of the "slow/stop" sign.

"They're bird deflectors," he said as he waved me by.

It must have something to do with Rieck's Lake Park, famous as a stop-over for migrating waterfowl and cranes.   When I got home, a quick search on the internet provided an explanation - and the good news.   Turns out, it's an easy way to minimize bird-wire collisions.

Also known as bird flight diverters, these yellow wire coils are the one of several new products in bird-wire collision avoidance technology.   The coils are a relatively economical way to make overhead wires, cables and guy wires more visible to birds, especially cranes and swans.  

The utility wires along the Great River Road are a deadly hazard to the birds flying back and forth between the wetlands at Riecks Lake and the Missississippi River.