03/06/2018 - Regulatory Rollback

Migratory Bird Treaty Act

by Hana Vizcarra, Leilani Doktor

The Environmental & Energy Law Program is tracking the environmental regulatory rollbacks of the Trump administration. Click here for the list of rules we are following. If you’re a reporter and would like to speak with an expert on this rule, please email us.

Why it Matters

The Migratory Bird Treaty Act (MBTA), 16 U.S.C. § 703-711, makes it unlawful to take (“harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct”) individuals of most bird species found in the United States, unless that taking is authorized by a permit. These protected bird species face many dangers in the form of long-line fishing, oil pits and spills, high-tension power lines, communications towers, and other large infrastructure. Bird deaths attributed to these activities and structures are known as “incidental (or unintentional) takes.” Enforcement of the MBTA has served to limit these incidental takes by incentivizing companies to develop and implement best practices and technologies to safeguard protected birds.

Many more birds are killed by incidental takes than direct takes, and for the past 50 years or so, both have been prohibited under the MBTA. Excluding incidental takes from the MBTA removes the incentive for companies and government agencies to protect birds. According to studies by the Audubon Society, this change could put up to 64 million birds per year at risk. 

Current Status

Incidental takes are no longer illegal under the MBTA. The Trump administration, in Department of the Interior’s Solicitor’s Opinion M- 37050, permanently withdrew the Obama administration’s Solicitor’s Opinion M-37041, which had affirmed that incidental taking of migratory birds was prohibited. 

July 31, 2019 A federal district judge largely denied the a motion to dismiss three challenges to the guidance memo brought by environmental groups and states. All but one claim survived the motion to dismiss and the judge consolidated the cases. Case No. 1:18-cv-04601, S.D.N.Y.


1918 Following a treaty between the U.S. and Great Britain to protect migratory birds, Congress passes the Migratory Bird Treaty Act. The MBTA gives authority and responsibility to the U.S. Fish and Wildlife Service to enforce the act and protect birds listed in the MBTA. Since being delegated authority to enforce the MBTA, the U.S. Fish and Wildlife Service has long recognized incidental takes as part of the prohibition on unauthorized taking of migratory birds.

Jan. 10, 2017 The Office of the Solicitor for the Department of Interior issues a Solicitor’s Opinion memorandum, M- 37041. Opinion M-37041 establishes that “incidental takes were unauthorized taking or killings prohibited under the MBTA.”

Trump Era

Dec. 22, 2017 The Office of the Solicitor for the Department of Interior issues a Solicitor’s Opinion memorandum, M- 37050, permanently withdrawing Opinion M-37041. The Trump administration’s interpretation finds that the MBTA’s prohibitions on pursuing, hunting, taking, capturing, killing apply only to affirmative actions that intend to take or kill migratory birds, their nests, or their eggs.

Jan. 10, 2018 A bi-partisan group of former Department of Interior officials, including  two former Deputy Secretaries of the Interior and five former Directors of the Fish and Wildlife Service, sends a letter to Interior Secretary Ryan Zinke requesting that the Department suspend the new interpretation of the MBTA and convene a bipartisan group of experts to consider the issue.

May 24, 2018 Two sets of environmental groups file suit in the U.S. District Court for the Southern District of New York challenging Interior’s December 2017 Solicitor’s Opinion. The National Audubon Society, American Bird Conservancy, Center for Biological Diversity, and Defenders of Wildlife argues the opinion was “unlawful and arbitrary and capricious.” National Audubon Society v. Interior, et al., No. 1:18-cv-04601 (S.D.N.Y.). The Natural Resources Defense Council and National Wildlife Federation argues it “misconstrues the act” and is thus unlawful. Both sets of plaintiffs ask the court to set aside the opinion and reinstate the Obama-era opinion. NRDC v. Interior, et al., No. 1:18-cv-04596 (S.D.N.Y.).

Sep. 6, 2018 Eight states, led by New York and California, sue Interior challenging its interpretation of the MBTA, which narrowed the scope of what is considered an “incidental take.” The states seek a declaration that the interpretation was unlawful because it “contradicts the plain meaning, structure, and intent” of the statute and “contravenes” the purpose of the act.

July 31, 2019 A federal district judge denied the federal government’s request to dismiss challenges to the guidance memo brought by environmental groups and states. The Department of Interior had argued that the cases should be dismissed for lack of standing or failure to state a claim. The judge did dismiss one of plaintiffs’ claims, the claim that the guidance should have gone through notice-and-comment procedures. The court agreed with defendants that interpretive rules are not required to do so. All other claims survived the motion to dismiss. The judge also consolidated the cases. Case No. 1:18-cv-04601, S.D.N.Y.

Thank you to Harvard Law student Leilani Doktor, JD 2019 for her assistance with this rule.