Seattle City Light trying to evict transmission tower trespasser

Seattle City Light has been trying unsuccessfully to evict an osprey that has chosen a transmission tower across the Duwamish River near Elliott Bay as the place to make his nest.

Osprey often nest in what are called “snags” – the uneven portion of the tree trunk that remains when the top of the tree has broken off.

“A tall snag near a body of water is ideal habitat,” a City Light spokesperson told TransmissionHub Aug. 9.

Utility poles and towers, especially near water, look like suitable alternatives. The trouble is, ospreys often have wingspans as wide as six feet and build nests as large as king-sized mattresses, the spokesperson said.

“If those wings touch the wrong spot, the nest gets too big or gets wet, then we see real problems, for the bird as well as us and our customers,” the spokesperson said.

The bird made his first nest on the right side of the superstructure, which supports about a dozen lines that feed a major industrial area. Crews put insulation over the 26-kV conductors closest to the nest to provide some protection, but the osprey had other ideas: he moved to the other end of the superstructure and started over.

“Maybe he didn’t like the color orange,” the spokesperson said.

For reasons including potential damage to its equipment and cascading outages, City Light prefers to have the creatures build their nests elsewhere, and has taken numerous steps to discourage the building of nests on towers and to encourage their construction elsewhere.

Those steps include topping its transmission towers with large rounded plastic pipe, like sections of culvert, so the birds lack good landing spots and so that sticks the birds drop on them will slide off. They also include the construction of nesting platforms on poles that are away from conductors. So far, however, none has proven successful in getting this particular bird to move.

“Osprey are stubborn,” the spokesperson said. “They will continue to come back to a particular spot if they’ve decided that’s where they want to be.”

While the spokesperson said it’s not uncommon to see these types of nests on towers, this particular case is a little unusual in that osprey nesting season has passed, and this bird is a single male. Most nests, City Light’s wildlife biologist said, are built by mating pairs of birds who will care for their young.

The biologist has a theory that evokes the opening line of Jane Austen’s Pride and Prejudice: perhaps the lone male is building the nest in an attempt to make himself more attractive to a potential mate.

“If he’s building a bachelor pad, we need to find him a better neighborhood; one that makes him happy and does not conflict with our operations,” the spokesperson said.

To that end, City Light crews are searching for potential areas to build a nesting platform for the male osprey. Once a site is found, it won’t take long to erect the platform. Getting the bird to move, however, may be another matter.

As frustrating and potentially problematic as it is, the spokesperson sees a silver lining to this dark cloud.

“The good news is the osprey population is really rebounding,” the spokesperson said. At present, the Seattle area has between 25 to 35 nesting pairs of osprey, with two to four new pairs arriving each year.