Migratory Bird Treaty Act

The Migratory Bird Treaty Act (MBTA), enacted in 1918, is one of the country’s oldest and most important wildlife conservation laws. It protects more than 1,000 species of birds by prohibiting the unauthorized “taking” or “killing” of such birds “at any time, by any means or in any manner.” For decades, the federal government applied this broad prohibition to both intentional acts, like hunting and poaching, and industrial activities that directly and foreseeably kill large numbers of birds, such as oil and gas development and pesticide applications.

NRDC v. U.S. Department of the Interior

But on December 22, 2017, the U.S. Department of the Interior (DOI) under President Trump reinterpreted the MBTA to apply only to activities that have as their specific purpose the taking or killing of birds, relying on a binding legal memo to significantly limit the scope of protection. Soon after, the U.S. Fish and Wildlife Service (FWS) began notifying companies that they were no longer required under the MBTA to take measures to avoid killing birds—measures like not clearing trees for natural gas pipeline construction during nesting seasons—and issued guidance on how the agency would implement the new interpretation.

In response, NRDC, the National Wildlife Federation, National Audubon Society, Defenders of Wildlife, Center for Biological Diversity, and American Bird Conservancy (as well as eight states) sued the Trump administration—and on August 11, 2020, the U.S. District Court for the Southern District of New York threw out DOI’s illegal reinterpretation.

The court wrote in its decision: “It is not only a sin to kill a mockingbird, it is also a crime. That has been the letter of the law for the past century. But if the Department of the Interior has its way, many mockingbirds and other migratory birds that delight people and support ecosystems throughout the country will be killed without legal consequence.” (The Trump administration appealed the district court decision to the U.S. Court of Appeals for the Second Circuit, but the new Biden administration dropped that effort.)

National Audubon Society v. U.S. Fish and Wildlife Service

Unfortunately, this wasn’t the only strategy the Trump administration was pursuing to roll back the MBTA. On January 7, 2021, in the waning days of the administration, the FWS published a regulation that codified the legal memo and MBTA interpretation that the federal court had already rejected.

NRDC and partners swiftly filed a new lawsuit in the Southern District of New York challenging the FWS’s rule. Simultaneously, we urged the Biden administration to reinstate the MBTA to its full conservation intent, including an incidental take permitting program, and to work with Congress to guard against future dismantling of this bedrock law.

These efforts paid off. With pressure from our pending lawsuit and our previous court victory, the Biden administration issued a new rule in October 2021 that repealed the regulation we challenged and restored incidental take protections for migratory birds. Having secured the protection of millions of birds, we voluntarily dismissed our second lawsuit.