Power line diverter study in final phase

By KIM FUNDINGSLAND, Staff Writer kfundingsland@ minotdailynews.com
COLEHARBOR – During the early morning and late evening hours, summer employees at Audubon National Widlife Refuge carefully traverse the large and often slippery rocks that protect the 3-mile-long Snake Creek embankment from the waves of Lake Sakakawea to the west and Lake Audubon to the east.


It is tedious and difficult work, but considered critical to a study that might have implications worldwide.


Above the embankment are huge power lines, some of which are decorated with experimental bird diverters. The diverters were hung on the lines in April 2007 as part of a study to determine the best method of limiting bird strikes, a problem that has been estimated to be responsible for up to 25 percent of the eagle deaths in the United States alone.


“They recently found an eagle under a power line not far from here,” said Larry Heintzelman, an Audubon NWR summer employee. “We walk the rocks and collect the dead birds. We also watch their flight patterns from 20 minutes before sunrise to 20 minutes after, and from 20 minutes before sunset to 20 minutes after. It’s just amazing to see how the birds react to the power lines and the diverters.”


Statistics from a similar effort in 2007 showed that far fewer birds died as a result of power line collisions on the Snake Creek Embankment than had died in 2006 when no diverters were in place. It’s hoped the study will help determine which of the three diverters being used along the embankment is most effective in reducing bird strikes.


“You can see them thinking and then they react because something is there,” said Heintzelman. “They usually back off, fly further down the line and then go over. The deflectors make them stop and think. You can see that it works.”


When the U.S. Fish and Wildlife Service issued suggested practices for avian protection on power lines in 2006, it was noted that power line electrocutions had claimed bald eagles, whooping cranes and peregrin falcons. No such birds have been recovered along the Snake Creek Embankment, but there have been a few other species that made surprise appearances.


“There was an orange crowned warbler we found dead. It’s not supposed to even be here,” said Heintzelman. “It’s an Oregon coastline migrant. Some of the others have been horned grebes, a Wilson’s phalarope and a brilliant yellow warbler.”


Heintzelman estimates the number of dead birds found along the embankment to be about three per day unless conditions become quite windy. On windy days birds are more likely to have trouble negotiating the power lines. Sometimes the wind forces the birds below the wires where they are more likely to be struck by vehicles on U.S. Highway 83.


The collecting of dead birds and visual observation will continue throughout the summer, completing the third and final year of the study along Snake Creek Embankment. Final information will be examined by the Fish & Wildlife Service and by the Western Area Power Administration headquartered in Lakewood, Colo. WPA owns the power lines crossing the embankment and has been searching for ways to reduce bird strikes in the U.S. and around the world. Because of the changing seasons and proximity to large bodies of water, the Snake Creek Embankment study is thought to be the most important study of bird diverters currently under way in the U.S.