On March 29, 2025, a Texas District Court ruled that the U.S. Fish and Wildlife Service (FWS) should have considered economic costs when crafting protections for the lesser-prairie chicken, a threatened species, under Section 4(d) of the Endangered Species Act (ESA). The decision in Kansas Natural Resource Coalition v. U.S. Fish and Wildlife Service could significantly impact how FWS develops 4(d) rules for threatened species, potentially leading to an approach that weighs both environmental and economic factors.

Section 9 of the ESA prohibits the “take” (e.g. harm, harass, kill capture) of endangered species. However, this prohibition does not necessarily extend to threatened species. Instead, Section 4(d) of the ESA instructs agencies to issue regulations deemed “necessary andadvisable” for the conservation of threatened species. For most of the ESA’s history, and most recently reflected in a May 2024 rule, FWS automatically extended the ESA’s endangered species “take” prohibition to all threatened species through a 4(d) “blanket rule,” unless it promulgates a specific 4(d) rule prescribing different treatment for a species.

Citing the Supreme Court’s recent decision to overturn the Chevron doctrine of judicial deference, the Texas District Court rejected FWS’s longstanding practice of issuing “blanket rules.” Rather, FWS must justify all threatened species protections as “necessary and advisable.” The court additionally found that Section 4(d) does not limit FWS to only considering the best available science. Ultimately, the court interpreted “advisable” to mean that FWS must weigh “all relevant factors,” including costs, when crafting protections for threatened species. The court found this conclusion is consistent with the ESA’s prohibition on considering costs in listing decisions.

If other courts adopt this ruling, it could reshape how the FWS regulates threatened species. By requiring economic factors to be considered when issuing 4(d) rules, this interpretation may lead to fewer restrictions on activities in areas that threatened species inhabit or fewer geographic limitations on such activities. This shift could also influence future interpretations of the ESA, setting a precedent for integrating cost considerations into wildlife conservation. It also could drive FWS to list more species as endangered than threatened, since the former type of listing entails mandatory take prohibitions. Stakeholders should stay informed about these developments to navigate the evolving regulatory landscape effectively.