The United States District Court for the District of Montana issued a decision (PDF) setting aside the 2009 Final Rule (PDF) that delisted the distinct population segment (DPS) of the gray wolf in the Northern Rocky Mountains, except in Wyoming.  The court found that the Endangered Species Act (ESA) does not allow the Fish and Wildlife Service (Service) to divide a DPS into a smaller taxonomy. 

The gray wolf was listed as endangered under the ESA in 1974.  The Service subsequently developed a wolf recovery plan, and the gray wolf was reintroduced in the northern Rockies in the mid-1990s.  Under the Bush Administration, the Service sought to delist the wolf in 2008 (including the Wyoming wolves), but environmental plaintiffs successfully enjoined implementation of that rule.  The 2009 Final Rule removed ESA protection for the gray wolves in Idaho and Montana, but preserved protection for the Wyoming Wolves noting that the state’s regulatory framework failed to meet the ESA’s requirements. 

In challenging the 2009 Final Rule, plaintiffs argued that the Service had violated the ESA by listing something less than a DPS (by only protecting the Wyoming wolves and excluding Idaho and Montana) as endangered and that the definition of a  "species" is nothing smaller than a DPS.  The Service defended its listing decision arguing that the ESA allows for listing of part of a DPS because the term "endangered species" means any species which is in danger of extinction throughout all or a significant portion of its range.  The court explained that the Service’s argument could not be reconciled with the plain reading of the ESA and that the term "species" excludes distinctions below that of a DPS.  The court further concluded that the Service’s interpretation of the ESA was not deserving of deference and was unreasonable.