Fake raptors an ineffective deterrent for wise osprey

The great horned owl perches on a crossarm and peers through sightless eyes across McWenneger Slough.

A few miles south, another solitary, motionless great horned owl loiters atop a crossarm on a power-line pole along Montana 82 near the Flathead River.

And to the east, not far from the turnoff to Echo Lake, yet another owl perches on yet another crossarm.

If an excited birder driving by grabs binoculars for a closer look, disappointment will soon roost. These great horned owls are fake.

Years ago, Flathead Electric Cooperative and other utilities installed numerous decoy owls in an attempt to scare other bird species away from power-line installations.

“In the 1970s and ’80s and early ’90s they were widely deployed,” said Wendy Ostrom-Price, a spokeswoman for Flathead Electric Cooperative.

“They used to put them everywhere, mainly for deterring osprey,” she said. “We haven’t used them for some time.”

The utility hoped the owls would discourage osprey from building their voluminous nests on crossarms. The birds’ large wing spans can touch two conductors at once and cause electrocution, the nests could damage the poles and other impacts could lead to outages, Ostrom-Price said.

“But the osprey weren’t stupid,” she said.

After a period of observing the stationary owls, the osprey got wise to the ploy, she said.

Today, Flathead Electric Cooperative uses other methods to discourage osprey from nesting, including installing slick fiberglass crossarms and other materials designed to make nesting as difficult as siting a fast-food joint in downtown Whitefish.

Ostrom-Price said the utility discovered that putting up separate nesting platforms for osprey created problems instead of solving them. She said the platforms attracted osprey that would sometimes build nests on the platforms and the power lines.

According to the Cornell Lab of Ornithology, “the osprey readily builds its nest on manmade structures, such as telephone poles, channel markers, duck blinds and nest platforms designed especially for it. Such platforms have become an important tool in re-establishing ospreys in areas where they had disappeared. In some areas nests are placed almost exclusively on artificial structures.”

The Cornell Lab of Ornithology added that osprey nests are built of sticks and lined with bark, sod, grasses, vines, algae and other materials. Nests can start out comparatively small, but “after generations of adding to the nest year after year, ospreys can end up with nests 10 to 13 feet deep and 3 to 6 feet in diameter,” the lab reported.

Meanwhile, Kevin McGowan, an ornithologist with the Cornell Lab, said real owls intimidate other birds.

“They’re pretty ferocious predators,” he said. “Everybody is pretty much afraid of them. They’re a logical choice (for a deterrent).”

McGowan said fake owls often replicate great horned owls because of the bird’s distinctive silhouette.

“You glance at it, you know what it is,” he said.

But other birds quickly figure out that the fake owls present no threat, McGowan said.

He said he once saw a pair of starlings nesting inside a broken decoy great horned owl.

An article in Transmission and Distribution World noted, “Birds are a major problem for utilities. They collide with overhead structures and conductors, contaminate insulators and equipment, and damage facilities, leading to customer interruptions.”

The Edison Electric Institute described several reasons power lines appeal to raptors: “Poles increase their range of vision and attack speed when hunting; they provide good hunting and roosting platforms; they are favorable sites for raptors to broadcast territory boundaries; and a good prey base exists along rights of ways.”

Modern versions of fake owls can be more sophisticated than those deployed years ago in the Flathead Valley. Solar-powered owls move from time to time, for example.

Ostrom-Price was surprised to learn that several of the region’s sham owls remain on hoot-less duty after years of deployment in sometimes harsh weather.

“I’m just impressed that they’re still out there,” she said.

Reporter Duncan Adams may be reached at dadams@dailyinterlake.com or 758-4407.