In a case we brought on behalf of the Center for Biological Diversity and Defenders of Wildlife, the federal district court in Arizona has issued an important ruling rejecting the Fish and Wildlife Service’s (FWS) refusal to list the cactus ferruginous pygmy-owl, one of the world’s smallest owls, as an endangered or threatened species, based on the agency’s unlawfully narrow interpretation of its listing duties under the Endangered Species Act (ESA). The ESA requires that species be listed if they are endangered or threatened throughout “all or a significant portion” of their range. Although the pygmy-owl is gravely imperiled in much of its range in Arizona and northern Mexico, FWS refused to list the species based on a policy that, in effect, equates a “significant portion” with the entirety of the species’ range. If this approach had been applied in the past, many of the most iconic species that have received critical protection under the ESA – such as the grizzly bear, bald eagle, and wolf – would never have been protected in the U.S. portions of their range. The Arizona district court has emphatically rejected that self-defeating approach to the Act on the grounds that it violates the plain language of the ESA and undermines the important conservation purposes of the law to protect and bring about the recovery of species such as pygmy-owl. A copy of the Court’s ruling can be found here and a copy of the Center for Biological Diversity’s press release can be found here.