Seattle City Light tries osprey deterrent on utility poles

Apr 25, 2011

Wildlife experts think they may have finally outsmarted the osprey, at least when it comes to keeping them off of utility poles. The hawk-like birds have caused power outages and harm to themselves by nesting on high voltage power lines.

Ospreys are pretty resourceful birds. When the tall, bare trees they used to nest in disappeared from the water’s edge, they figured out utility poles were a close substitute. Whenever humans try to stop them from using the poles, ospreys find a workaround.

Ron Tressler, a wildlife biologist who works for Seattle City Light, says once an osprey builds a nest somewhere, it's pretty determined to come back year after year. Then it becomes even harder to make a utility pole undesirable:

"You know, there’s a number of things that have been tried and really just don’t work,” he says.

Some of the attempts that have failed include:

  • Triangles between lines on the cross arms (Tressler says osprey use them to brace their sticks) 
  • Bird spikes on the cross arms (again, he says the birds build right among them)
  • Owl decoys (these likely just make osprey laugh)

The utility might finally have a solution. It asked Jim Kaiser, a wildlife biologist who focuses on ospreys, and Ed Schulz, a retired electrical engineer, for help. They built a deterrent out of a big PVC pipe that’s been cut in half. That creates a tunnel over the former perch too small for an osprey to build a nest under. The pipe’s round shape could also keep birds from nesting on top. 

Right now, Seattle City Light is only trying the deterrent in one location. It’s on a pole on Harbor Island that caught fire last year from an osprey nest.

Tressler says even if the new system works, he doesn’t expect the utility to install a bunch of them. It already builds and maintains special platforms for birds to nest on. And most of those resourceful osprey have figured out that’s the way to go.