Professor Dave Owen’s insightful empirical analysis of the Endangered Species Act’s (“ESA”) prohibition on destruction of critical habitat should be useful in improving the Act’s effectiveness. The title of his paper, Critical Habitat and the Challenge of Regulating Small Harms, however, is misleading in its characterization of impacts addressed in U.S. Fish and Wildlife Service (“FWS”) and National Marine Fisheries Service (collectively “the Services”) “biological opinions.” A biological opinion is the culmination of “formal” consultation. The overwhelming majority of consultations, however, are “informal” and do not conclude with the issuance of a biological opinion. The two types of consultations are quite different.