Golden eagles, wind farms on collision course?

The western wind that whips across Pittsburgh into the mountain ridges of central Pennsylvania has the power to send thousands of migrating eagles soaring for miles and to keep 115-foot-long windmill blades spinning.

But if birds and blades interact, the results could be fatal.

The National Aviary on the North Side and Powdermill Avian Research Center in Westmoreland County are partners in a project to track the biannual migration of eastern golden eagles through the Appalachian Mountains. They plan to share what they learn with agencies that permit wind farms.

“Wind power is an important issue,” said Todd Katzner, director of conservation and field research at the aviary. “My feeling is that there are ways to do it right and ways to do it wrong, and our goal is to provide information about how to do it right.”

Pennsylvania leads the eastern U.S. in wind energy production, with more than 153 megawatts of wind power generated annually — enough to power almost 100,000 homes — and has several more wind farms planned, according to the state Department of Environmental Protection.

The golden eagles, a protected species, don’t know how to react to spinning windmills. They tend to fly straight into the blades, which have killed birds in other states, Katzner said. He said he doesn’t know whether any birds in Pennsylvania have been hit.

In November, Katzner and several other researchers caught two eastern golden eagles near Central City, Somerset County, and attached solar-powered telemetry devices to their backs. Over the next several years, the team plans to track dozens more birds.

The 3-ounce devices transmit to satellites where, how high and how fast the birds are flying.

The Department of Environmental Protection — which issues permits for wind farms — would be interested in learning about the eagles’ flight patterns, said spokesman Tom Rathbun.

“It is important to note that in the Northeastern U.S., wind farms are relatively new,” Rathbun said in an e-mail. “I think everyone involved in the process — regulatory agencies, environmental groups and the wind power industry — all agree that further data is needed to determine if wind turbines do indeed present a danger to wildlife.”

At least 500 eastern golden eagles, which have 7-foot wingspans, soared through Western Pennsylvania this fall on their way south to warmer states. The two tagged eagles are wintering in southern West Virginia and eastern Kentucky.

Eastern golden eagles — whose territory stretches from northern Canada through the Middle Atlantic and Southern states — have a distinct breeding ground and could be genetically different from other golden eagles, which occupy much of North America and parts of Europe, Asia and Africa, Katzner said. He hopes to genetically test the eastern golden eagles to learn whether they are a distinct species.

Avoiding collisions between golden eagles and future wind turbines could be as simple as shifting a turbine’s planned location by a few hundred feet, Katzner said.

“Birds and wind companies use the same resource,” Katzner said. “In my opinion, it is possible for them to share it.”