On December 22, 2017, the US Department of Interior, Office of the Solicitor, released an opinion (see here) concluding that the Migratory Bird Treaty Act (MBTA) does not apply to the incidental (non-purposeful) killing of migratory birds (New Opinion). The New Opinion reverses the Solicitor’s January 10, 2017, opinion, which concluded that “the MBTA’s broad prohibition on taking and killing migratory birds by any means and in any manner includes incidental taking and killing.” The January 2017 opinion was suspended on February 6, 2017, pending review. The New Opinion will have broad implications for siting of new infrastructure, including wind power.

The MBTA prohibits the “take” of migratory birds without a permit. By regulation, the US Fish and Wildlife Service (USFWS) has defined take to mean “to pursue, hunt, shoot, wound, kill, trap, capture, or collect, or attempt to pursue, hunt, shoot, wound, kill, trap, capture, or collect.”1 In response to the now-withdrawn January 2017 Solicitor’s opinion, the USFWS issued guidance that further defined killing to include “any action that directly and foreseeably causes the death of a migratory bird.”2

Nearly all bird species native to the US or its territories are covered by the MBTA, with the USFWS listing 1,026 species of migratory birds.3 The USFWS estimates that billions of birds are killed in the US each year due to anthropogenic causes, with 2.4 billion birds killed by cats alone. Other causes include collisions with building glass (303.5 million), vehicles (200 million), and power lines (25 million). Thus, the scope of the MBTA’s probation on taking migratory birds is significant to almost all human activity and is not limited to what are traditionally considered to be environmentally sensitive industrial sectors.

Following federal prosecutions for the incidental taking of migratory birds beginning in the 1970s, courts have split on whether the MBTA prohibits incidental takes, and, if so, to what extent. The Courts of Appeal for the Fifth, Eighth, and Ninth Circuits have held that the MBTA does not cover incidental takes. For example, in Seattle Audubon Society v. Evans, 952 F.2d 297, 302 (9th Cir. 1991), the Ninth Circuit explained that “taking” as defined in the MBTA “describes physical conduct of the sort engaged in by hunters and poachers,” and, as a result, does not criminalize the death of birds caused by habitat destruction.4

In contrast, the Courts of Appeal for the Second and Tenth Circuits have extended the MBTA to some incidental takes, but have borrowed from tort law to impose limits on its reach. For example, in U.S. v. FMC Corp., 572 F.2d 902, 905 (2nd Cir. 1978), the Second Circuit upheld a conviction for birds killed by water contaminated as a result of the defendant corporation’s manufacture of pesticides by analogizing to strict tort liability for extra-hazardous activity, while explaining that “construction that would bring every killing within the statute, such as deaths caused by automobiles, airplanes, plate glass modern office buildings or picture windows in residential dwellings into which birds fly, would offend reason and common sense.”5

Noting the history and purpose of the MBTA, and the potential lack of clarity in the approaches taken by the Second and Tenth Circuits, the New Opinion adopts a bright line, consistent with the Fifth, Eighth, and Ninth Circuits, that the MBTA applies only to “direct and affirmative purposeful actions” to kill or capture migratory birds, their nests, or their eggs. The New Opinion is anticipated to reduce uncertainty throughout all industrial sectors, particularly among those—such as energy, mining, timber, and chemical—that have seen prosecutions for incidental takes and that previously had to rely on the government’s prosecutorial discretion.