The Center for Biological Diversity and the Sierra Club (collectively the Center) alleged that the final environmental impact statement (EIS) of the United States Forest Service (USFS) was in violation of the National Environmental Policy Act (NEPA)[1] and NEPA's implementing regulations because the EIS improperly concluded that the northern goshawk (Accipiter gentilis) was a habitat generalist. The district court granted summary judgment to USFS. The Ninth Circuit reversed the district court's grant of summary judgment and remanded to the district court, directing the district court to remand the final EIS to USFS.

USFS created the Northern Goshawk Scientific Committee (the Committee) to review the habitat management needs of the northern goshawk in the Southwestern Region of the United States in response to concerns about impact from logging. The Committee published a report entitled Management Recommendations for the Northern Goshawk in the Southwestern United States (MNRG), which stated the goshawk was a habitat generalist, meaning it can survive in different types of forest and does not need a particular type of forest in order to survive. USFS then published notice of its intent to prepare an EIS for the Southwestern Region in order to incorporate management of the northern goshawk into forest and land management in the area, and received comments challenging the finding that the goshawk was a habitat generalist. Both the Arizona Game and Fish Department (AGFD) and the United States Fish and Wildlife Service (FWS) submitted comments, including scientific information that directly controverted the MNRG's conclusion that the northern goshawk was a habitat generalist. USFS responded to AGFD and FWS in letters, citing studies showing the northern goshawk to occupy many different types of forests. USFS created a Goshawk Interagency Implementation Team to analyze the findings and recommendations of the MNRG and to propose revisions to the recommendations.

In 1994, USFS issued a draft EIS with five different alternatives. This draft EIS noted that the recommendations of the MNRG were included in all five alternatives, and therefore each alternative encompassed the best scientific data available. The draft EIS summarized the comments that USFS had received, but did not specifically address the comments that argued that the northern goshawk was not a habitat generalist. After issuing the draft EIS, USFS accepted more comments. Citing various scientific studies, AGFD, the New Mexico Department of Game and Fish, a wildlife biologist working for USFS who had published research on the northern goshawk, and the Center for Biological Diversity renewed the challenge to USFS's determination that the northern goshawk was a habitat generalist. The state agencies noted that they were renewing this challenge because the issue had not been sufficiently addressed in the draft EIS.

USFS's final EIS included minor changes from the draft EIS, added a sixth alternative to respond to the Mexican Spotted Owl Recovery Plan, and included a section that contained and responded to the comments that USFS had received on the draft EIS, but again did not address the comments challenging its conclusion that the northern goshawk was a habitat generalist.

The Center challenged the final EIS on three grounds: 1) inadequate analysis of the controversy over whether the northern goshawk was a habitat generalist, 2) failure to discuss scientific studies with results contrary to USFS's finding that the northern goshawk was a habitat generalist, and 3) failure to respond to comments on the scientific debate over whether the northern goshawk is a habitat specialist or a habitat generalist. The Ninth Circuit reviewed the district court's grant of summary judgment de novo, and USFS's compliance with NEPA under the Administrative Procedure Act (APA)[2] standard requiring that agency actions be set aside if prescribed legal procedures are not followed. In Kern v. United States Bureau of Land Management,[3] the Ninth Circuit adopted a rule of reason standard to analyze the adequacy and thoroughness of the discussion of environmental consequences in the EIS.

The Ninth Circuit held that USFS violated NEPA because it did not consider or address the scientific evidence that the northern goshawk was not a habitat generalist. The Ninth Circuit noted that NEPA required the agency to consider all the important aspects of a proposed action that would have an effect on the environment and inform the public that it has carried out this analysis. Although NEPA does not require USFS to make a particular decision, it does require USFS to address all the available scientific information. In addition, one of NEPA's implementing regulations, 40 C.F.R. section 1502.9(b), requires USFS to "disclose and discuss responsible opposing viewpoints."[4] The Ninth Circuit held that, since USFS did not discuss in its final EIS the scientific viewpoint that the northern goshawk was a habitat specialist, it violated 40 C.F.R. section 1502.9(b): "[T]he Final EIS fail[ed] to disclose and discuss responsible opposing scientific viewpoints in the final statement itself in violation of NEPA and the implementing regulations."[5] The Ninth Circuit rejected USFS's argument that its summary comment stating that opposing views existed sufficiently addressed the debate over whether the northern goshawk was a habitat generalist. The Ninth Circuit also rejected USFS's argument that the habitat generalist controversy was sufficiently addressed by documents in the record, and noted that NEPA and its accompanying regulations required "the agency [to] disclose responsible opposing scientific opinion and indicate its response in the text of the final statement itself."[6]

The Ninth Circuit remanded the case to the district court, and directed the district court to remand the final EIS to USFS.