(Reuters) - A coalition of conservation groups sued the Trump administration on Thursday, accusing the government of slashing protections for migratory birds.

U.S. President Donald Trump gestures as he speaks before the signing ceremony for S. 2155 - Economic Growth, Regulatory Relief, and Consumer Protection Act in the Roosevelt Room at the White House in Washington, U.S., May 24, 2018. REUTERS/Kevin Lamarque

At issue is the Migratory Bird Treaty Act, which the National Audubon Society and other plaintiffs say has been undermined. In the past, the act helped hold parties responsible for actions that killed or injured migratory birds.

But in December, the Trump administration said energy companies and other businesses that accidentally kill migratory birds will no longer be criminally prosecuted.

“As you can imagine, many causes of bird fatalities -- including oil spills -- could fall into this ‘unintentional’ category, so we’re taking the administration to court,” David Yarnold, president and CEO of the National Audubon Society, a plaintiff in the lawsuit, said in a statement.

Plaintiffs also include the American Bird Conservancy, the Center for Biological Diversity, and Defenders of Wildlife. The lawsuit was filed in the U.S. District Court for the Southern District of New York.

Defendants are the U.S. Department of the Interior, U.S. Fish and Wildlife Service and Daniel Jorjani, the Interior Department’s principal deputy solicitor.

The U.S. Attorney’s Office for the Southern District of New York, representing the government in the lawsuit, declined to comment. Representatives for the Fish and Wildlife Service, interior and justice departments also declined comment.

The Trump administration’s December move, in a legal memo from the Interior Department, reversed a longstanding practice at the agency and a last-minute rule implemented by the outgoing Obama administration. It came after several appeals courts ruled that the government was interpreting a century-old law aimed at protecting birds too broadly.

In the legal opinion, Jorjani said that a 1918 law that officials have used to prosecute those who kill birds “incidentally” as part of doing business was really aimed at preventing poaching and hunting without a license.

The Migratory Bird Treaty Act “applies only to direct and affirmative purposeful actions that reduce migratory birds, their eggs, or their nests, by killing or capturing, to human control,” Jorjani wrote.

The memo is already being followed, the lawsuit said, and one or more companies constructing natural gas pipelines were told they may cut down trees with nesting birds during the breeding season.

The conservation groups request that the court vacate the memo and declare the defendants “revert to their prior, correct longstanding interpretation and policy,” the lawsuit said.