On August 28, 2017, the U.S. Court of Appeals for the Ninth Circuit affirmed a district court decision upholding a U.S. Fish and Wildlife Service (“Service”) determination that the Sonoran Desert Area bald eagle does not constitute a distinct population segment (“DPS”) under the Endangered Species Act (“ESA”). Ctr. for Biological Diversity v. Zinke, No. 14-17513, 2017 WL 3687443 (9th Cir. Aug. 28, 2017). The court deferred to the Service’s interpretation of its DPS policy, holding that the Service reasonably applied the relevant factors and considered scientific evidence to support its decision.
The ESA makes reference to, but does not define, the term “distinct population segment.” As a consequence, the Service has developed a DPS policy, which states that a population segment must be both discrete and significant. The parties agreed that the desert eagle population was discrete, but disputed whether the population was significant. Pursuant to the Service’s DPS policy, a determination regarding significance requires consideration of the following factors:
- Persistence of the DPS in an ecological setting unusual or unique for the taxon,
- Evidence that loss of the DPS would result in a significant gap in the range of a taxon,
- Evidence that the DPS represents the only surviving natural occurrence of a taxon that may be more abundant elsewhere as an introduced population outside its historic range, or
- Evidence that the DPS differs markedly from other populations of the species in its genetic characteristics.
Plaintiffs challenged the Service’s determination with respect to the first two factors.
To begin with, the Service concluded that the proposed...
