The U.S. Court of Appeals for the Ninth Circuit amended an opinion it filed earlier this year in Butte Environmental Council v. U.S. Army Corps of Engineers, which we wrote about here.  The case concerns a challenge to the Fish and Wildlife Service’s (Service) finding that a proposed business park would not adversely modify the critical habitat of three listed species under the Endangered Species Act (ESA). While the Ninth Circuit did not change its holding from the June opinion (PDF), it did clarify previous dicta concerning the Service’s analysis of adverse modification under the ESA.  In a footnote, the opinion now states that the court “express[es] no opinion on whether the ‘adverse modification’ inquiry under section 7 of the ESA properly focuses on the effects of an action on a particular unit of critical habitat or on total critical habitat nationwide.”  The court had previously highlighted the fact that the proposed project would affect only a very small percentage loss of the total critical habitat for the species.  In its amended opinion (PDF), the court revised its analysis to include the percentage loss for each species’ unit in addition to the percentage of nationwide loss.  It concluded that the project would destroy only a very small percentage of each affected species’ critical habitat whether viewed on a unit or nationwide basis, and, therefore, the Service’s determination that critical habitat would be destroyed was not inconsistent with its finding of no “adverse modification.”