In a recent case, Arizona Cattle Growers Association v. Salazar, the Ninth Circuit Court of Appeals upheld a designation by the U.S. Fish and Wildlife Service of approximately 8.6 million acres of Federal land as critical habitat for the Mexican Spotted Owl, a threatened species under the Endangered Species Act (“ESA”). In making the designation, FWS interpreted the word “occupied” in the ESA’s critical habitat provision to include not only areas where owls are found, but areas where owls are likely to be present as well.


Arizona Cattle Growers’ Association (“Arizona Cattle”) challenged the FWS designation in the Arizona District Court on the grounds that FWS interpreted “occupied” too broadly, and that “occupied” should be interpreted more narrowly as the area in which the species “resides.”  Arizona Cattle also argued that FWS calculated the economic impacts of the designation by applying an impermissible “baseline” approach.  The District Court entered summary judgment rejecting both challenges, and Arizona Cattle appealed.

The Ninth Circuit panel divided the question of the meaning of the word “occupied,” as used in the ESA, into two prongs: 1) uncertainty – “a factor when the FWS has reason to believe that owls are present in a given area, but lacks conclusive proof of their presence”; and 2) frequency – “a factor when owls are shown to have only an intermittent presence in a given area.”  With regard to the uncertainty issue, the Court ruled that an ESA provision that an agency must determine critical habitat using “the best scientific data available” does not require that FWS “act only when it can justify its decision with absolute confidence,” but “accepts agency decisions in the face of uncertainty.”  The Court granted FWS deference in this regard, citing the standard of review used in earlier Ninth Circuit cases, “[i]n recognition of the agency’s technical expertise the court usually defers to the agency’s analysis, particularly within its area of competence.”

With regard to frequency, the Court stated that a species need not be present continuously for a habitat to be considered “occupied,” and ruled that the FWS has authority to designate as “occupied” “areas that the owl uses with sufficient regularity that it is likely to be present during any reasonable span of time.”  The Court cautioned however that the FWS could “go too far” by designating areas not used by owls as “occupied” simply because those areas are suitable for future occupancy.

The Court’s analysis and ruling on the baseline issue will be the subject of a future article that will be published on this blog.