Hundreds of bird flight diverters are being clamped to overhead power lines near Coleharbor in hopes of avoiding hundreds of bird deaths caused when birds accidentally fly into the wires.

Western Area Power Administration is installing the bird diverters on three spans of power lines that run parallel to U.S. 83 along the causeway that separates lakes Sakakawea and Audubon.

The hope is to cut the number of bird deaths from under 1,000 annually to fewer than 500, said Misti Schriner, a Western biologist.

"We'd like to see zero, but nothing is 100 percent effective," she said Thursday by cellular telephone while on site.

"It's an area where birds fly from Audubon to Sakakawea or vice versa," said Terry Ellsworth, a Bismarck biologist for the U.S. Fish and Wildlife Service, which is cooperating in the project. "They come off of Lake Sakakawea, which is much lower, and rise over the embankment to Audubon. From Lake Audubon, they drop down to come across."

From either direction, some birds don't see the power lines and fly into them.

Everything from small songbirds to much larger geese and pelicans have hit the lines, Schriner said.

Three designs of diverters were being put up. The hope is to finish the work today.

Three hundred of each diverter design were being installed in 1,000-foot spans along the causeway. The spans fitted with diverters are separated from each other by three empty spans.

One type of diverter is a yellow coil that's wrapped around the line to increase the "visual diameter" of the wire, Schriner said. Another diverter resembles an orange waffle that hangs from the line and swings in the wind, allowing birds to see the movement, she said.

The third diverter resembles a large card and has yellow and orange reflective patches, Schriner said. It also glows in the dark.

Western already has collected three years' worth of data on bird strikes along the causeway. Plans call for people to walk the causeway again this summer to conduct another pedestrian survey of bird fatalities. The findings will help evaluate the effectiveness of the different diverter types.

The USFWS bought the diverters through an $80,000 research grant, Schriner said. The Avian Power Line Interaction Committee is funding the pedestrian surveys, and Western is paying for installation of the diverters, she added.

"Ithink it provides us with a much bigger benefit than just birds running into the line on the causeway. If the technology works, we will try to make the most efficient marking devices," Ellsworth said. "Western could have gone the cheap way and put up markers and said, 'We've done all we can.' They chose to take a closer look at this."

(Reach outdoor writer Richard Hinton at 250-8256 or richard.hinton@;bismarcktribune.com.)