In the first case of its kind in the US, the Department of Justice (DoJ) charged the energy company with causing the death of 14 eagles and 149 other birds under the Migratory Birds Treaty Act.
Duke has reached a settlement with the DoJ to pay a fine and restitution to the North American Wetlands Conservation Fund, the Wyoming Game and Fish Department and the National Fish and Wildlife Foundation.
The firm has also been placed on probation for five years, during which time it must implement an environmental compliance plan aimed at preventing bird deaths at the company's four commercial wind projects in the state.
The charges stem from the discovery of 14 dead golden eagles and 149 other protected birds, including hawks, blackbirds, larks, wrens and sparrows by the company at its 99MW Campbell Hill and 200MW Top of the World wind projects in Converse County between 2009 and 2013.
The company faced the charges because it was deemed not to have given proper consideration to the risk of bird deaths when planning the wind farms.
"The service works cooperatively with companies that make all reasonable efforts to avoid killing migratory birds during design, construction and operation of industrial facilities," said William Woody, assistant director for law enforcement of the U.S. Fish and Wildlife Service, which was involved in the investigation.
"But we will continue to investigate and refer for prosecution cases in which companies — in any sector, including the wind industry — fail to comply with the laws that protect the public's wildlife resources."
The DoJ said that the company cooperated with the investigation and has already implemented measures aimed at minimising bird deaths at the sites.