On April 17, 2025, the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) (together, the “Services”) published a proposed rule to rescind the current regulatory definition of “harm” under the Endangered Species Act (ESA) at 50 C.F.R. § 17.3. The existing definition, which includes “significant habitat modification or degradation” that actually kills or injures listed species, has long been a point of legal and policy contention. The Services now conclude that the definition does not reflect the best meaning of the statutory term “take” and is inconsistent with the ESA’s text, structure, and historical understanding. Public comments are due by May 19, 2025.
The ESA prohibits the “take” of endangered species, which the statute defines as including a range of actions such as “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect.” Since 1975, the Services have interpreted “harm” to include indirect actions—such as habitat degradation—that significantly impair essential behavioral patterns. In Babbitt v. Sweet Home, 515 U.S. 687 (1995), the Supreme Court upheld the Services’ interpretation under Chevron deference, which allowed courts to defer to an agency’s permissible interpretation of an ambiguous statute. Justice Scalia, joined by Chief Justice Rehnquist and Justice Thomas, dissented, arguing that the definition stretched the meaning of “take” beyond its historical usage and violated established canons of statutory interpretation.
In 2024, the Supreme Court overruled Chevron deference in Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024), holding that agencies must adopt the “single, best meaning” of a statute, rather than merely a permissible one. Relying on Loper Bright and Justice Scalia’s Sweet Home dissent, the Services in the proposed rule take the position that the current regulatory definition of “harm” extends the ESA beyond what the statute authorizes. They emphasize that “take” historically referred to affirmative acts directed at individual animals, such as killing or capturing, not to habitat changes with incidental effects.
In the proposed rule, the Services stress that the rescission would be prospective only and would not affect existing permits. Nor would it alter the statutory definition of “take,” which remains broad and continues to encompass “harm.” However, by eliminating the current regulatory definition of “harm,” the Services aim to realign their interpretation of “take” with what they believe to be its narrowest and most textually faithful reading. The Services do not propose a new definition to replace the rescinded one.
The proposed rule represents a significant departure from longstanding agency practice. By excluding habitat modification from the definition of “harm,” the Services would effectively narrow the scope of activities subject to incidental take prohibitions. This change could ease regulatory burdens for landowners, project developers, and other regulated entities whose activities may affect listed species indirectly through habitat impacts.
The proposed rule is consistent with the Trump administration’s efforts to narrow wildlife protection statutes’ applicability. On April 11, 2025, the Acting Solicitor of the Department of the Interior issued Memorandum No. M-37085 reinstating a 2017 Solicitor’s Opinion that concluded that the Migratory Bird Treaty Act does not prohibit the accidental or incidental taking or killing of migratory birds.
If you have any questions, please contact Katie Schroder or Cormac Bloomfield.