A major U.S. power company has pleaded guilty to killing eagles and other birds at wind farms as part of the first enforcement of environmental laws protecting birds against wind energy facilities.

Under the settlement Friday, North Carolina-based Duke Energy Corp. and its renewable energy arm agreed to pay $1 million. Much of the money will go toward conservation efforts.

The company pleaded guilty to killing 14 eagles and 149 other birds at two wind farms outside Casper, Wyo., from 2009 to 2013.

Wind farms are clusters of turbines as tall as 30-story buildings, with spinning rotors.

Before the case, no wind energy company had been prosecuted for the death of an eagle or other protected bird — even though such deaths are usually a federal violation.

Kansas is a major wind energy producer. The state’s high potential capacity for wind power is second only behind Texas.

Once a wind farm is built, there is little a company can do to stop the deaths. Some companies have tried using radar to detect birds and to shut down the turbines when they get too close. Others have used human spotters to warn when birds are flying too close to the blades. Another tactic has been to remove vegetation to reduce the prey the birds like to eat.