## Facts

- Gray wolves were historically widespread in the lower forty-eight states but were largely eradicated through government-authorized predator control in the early twentieth century.
- Wolves later received federal protection under endangered-species legislation and then the Endangered Species Act (ESA).
- In 2011, the U.S. Fish and Wildlife Service (FWS) issued a rule that (1) designated the Western Great Lakes gray wolf as a “distinct population segment” (DPS) and (2) delisted that DPS as recovered based on conditions in its current range.
- Humane Society and other organizations challenged the rule under the Administrative Procedure Act (APA) as contrary to the ESA and arbitrary and capricious.
- The district court vacated the rule and reinstated ESA protections for Western Great Lakes wolves.
- FWS, several states, and intervening hunting and sportsmen’s groups appealed.

## Issues

1. Whether the ESA permits FWS to designate a DPS and delist that DPS in a single rulemaking.
2. Whether the 2011 delisting rule was arbitrary and capricious for failing to assess the effect of carving out and delisting the DPS on the remaining listed gray wolf population.
3. Whether the 2011 delisting rule was arbitrary and capricious for inadequately addressing the relevance of the species’ lost historical range to the ESA’s “throughout all or a significant portion of its range” standard.

## Decision

- The D.C. Circuit affirmed the district court’s vacatur of the 2011 rule.
- The court held the ESA does not categorically bar FWS from concurrently designating and delisting a DPS.
- The court nevertheless held the 2011 rule was arbitrary and capricious because FWS failed to:
  - Evaluate the consequences of removing protections for the Western Great Lakes wolves on what would remain listed elsewhere; and
  - Provide a reasoned explanation addressing the significance of the gray wolf’s lost historical range.
- As a result, Western Great Lakes wolves remained protected under the ESA following vacatur.

## Legal Principles

- The ESA allows FWS to list or delist a “species,” including a validly designated DPS, and the statute does not forbid concurrent DPS designation and delisting in a single rule.
- DPS authority cannot be used to functionally reduce protections for a previously listed entity without analyzing the impacts on the remainder of the listed population.
- Under the APA, agency action is arbitrary and capricious if the agency fails to consider important aspects of the problem or to connect its factual findings to its decision with a reasoned explanation.
- ESA determinations applying “throughout all or a significant portion of its range” must address, in a reasoned way, how loss of historical range bears on delisting; focusing only on current range without adequate explanation can be arbitrary.

## Conclusion

The D.C. Circuit upheld FWS’s general authority to designate and delist a DPS in one rule but vacated the Western Great Lakes gray wolf delisting because the agency did not adequately analyze effects on the remaining listed wolves or explain how the species’ lost historical range factored into the ESA delisting determination.


Humane Soc'y of the U.S. v. Zinke, 865 F.3d 585 (D.C. Cir. 2017)