Humane Soc. of U.S. v. Kempthorne
Summary: Environmental groups brought challenge under the Endangered Species Act (ESA) against a Rule promulgated by the Fish and Wildlife Service (FWS) designating a particular geographic group of gray wolves as a “distinct population segment” (DPS) and removing the particular group from the endangered species list. The United States District Court, District of Columbia, held that the ESA is ambiguous with respect to whether the ESA permits FWS to use the DPS tool to remove ESA protections from a healthy sub-population of a listed species, and that the FWS rule was not entitled to Chevron deference, because the plain meaning of the statute is silent and/or ambiguous as to the particular issue at hand and there is no permissible agency construction to which the Court could defer. Lastly, the Court found that vacatur of the FWS Rule prior to remand was appropriate, because of the FWS’ failure to explain how its interpretation of the ESA comported with the policy objectives of the ESA, and because vacatur would result in very little to no confusion or inefficiency.