This story was updated at 12:27 p.m. EDT.

Exxon Mobil Corp. pleaded guilty in federal court in Denver to killing at least 85 protected waterfowl, hawks and owls in five states over the past five years, the Department of Justice announced today.

The birds died from exposure to natural gas well reserve pits and waste water storage facilities at Exxon Mobil drilling and production facilities in Colorado, Kansas, Oklahoma, Texas and Wyoming between 2004 and 2009.

Under the plea agreement reached yesterday with DOJ, the company will pay $600,000, as well as make changes to prevent related deaths in the future. Exxon told the court it has already spent $2.5 million on the effort.

Exxon will pay $400,000 in fines, which will be deposited into the federally administered North American Wetlands Conservation Fund, and $200,000 in community service payments, which will be sent to a nonprofit waterfowl rehabilitation foundation in Colorado and the congressionally chartered National Fish and Wildlife Foundation.

During a three-year probationary period, Exxon Mobil has also agreed to implement an environmental compliance plan to prevent future bird deaths at the company's facilities in the five affected states.

"The environmental compliance plan that Exxon Mobil has agreed to in this multi-district plea agreement is an important step in protecting migratory birds in these five states," said John Cruden, acting assistant attorney general for the Justice Department's Environment and Natural Resources Division.

Cruden said Exxon's cooperation in the case provided a useful example to other companies charged with violating the Migratory Bird Treaty Act.

"Exxon Mobil has worked with us and we commend them for that," Cruden said. "The company took steps to minimize risks to the birds when this was brought to their attention."

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