Wilderness Watch v. U.S. Fish and Wildlife Service

Bighorn sheep in the Kofa wilderness area declined due to hunting, hiking, and relocation; a 2007 Fish and Wildlife Service (defendant) investigative report identified water scarcity as a critical factor but also listed other viable interventions -- ending relocation and hunting, reducing predation, closing trails temporarily -- without stating that new water structures were necessary, and even suggested building any structures outside Kofa to avoid a necessity finding under the Wilderness Act's section 1133(c). The Service nonetheless built two structures within Kofa in 2007. Wilderness Watch and other groups (plaintiffs) sued, and the district court held the agency's necessity determination rational and granted summary judgment for the Service; the plaintiffs appealed.

Whether a federal agency must explain its decision not to use the least intrusive conservation method available when building structures within a designated wilderness area for sheep conservation.