ESA Incidental-Take Plans Must Compare the Biological Value of Lost and Replacement Habitat Before Relying on Translocation/Mitigation Assumptions

Case: Friends of Animals v. U.S. Fish and Wildlife Service (No. 25-4021)
Court: United States Court of Appeals for the Tenth Circuit
Date: August 12, 2026
Author: BACHARACH, Circuit Judge (with MORITZ and FEDERICO, Circuit Judges)

1. Introduction

This published Tenth Circuit decision addresses how the U.S. Fish and Wildlife Service (“Service”) may authorize development-related “incidental take” of a threatened species under the Endangered Species Act (“ESA”) while satisfying both ESA safeguards and the “hard look” demanded by the National Environmental Policy Act (“NEPA”). The case arises from the Service’s 2018 General Conservation Plan (“Plan”) for Utah prairie dogs in seven counties in southwest Utah, along with “master permits” issued to counties that could then grant developers “certificates of inclusion.”

Parties. Friends of Animals (Plaintiff–Appellant) challenged the Plan and permits; the U.S. Fish and Wildlife Service (Defendant–Appellee) defended them.

Core tensions and issues. The opinion frames a practical conflict: development occurs where prairie dog colonies persist, yet the ESA requires that authorized take be minimized/mitigated and not jeopardize the species. The appeal distilled into two thematic questions:

  1. Habitat comparison: Can the Service “fully offset” habitat and prairie dog losses primarily through translocation without comparing the suitability/“biological value” of the habitat being destroyed versus the habitat being provided? The court answered no.
  2. Logistical contingencies (funding/implementation uncertainty): Must the Service foresee every contingency (e.g., funding shortfalls), or can it rely on regulatory experience and flexible mechanisms? The court answered it can reasonably rely on expertise and experience.

2. Summary of the Opinion

The Tenth Circuit reversed the district court and held that the Service acted arbitrarily and capriciously (under the Administrative Procedure Act) in key respects under both the ESA and NEPA:

  • ESA (mitigation/minimization): The Service arbitrarily and capriciously approved the Plan’s mitigation framework because it did not require a comparison of the “biological value” of habitat lost to development against habitat provided through mitigation—especially where the Plan allowed substantial loss in major development areas that the Service itself recognized could have “high” conservation value.
  • ESA (jeopardy/survival and recovery): The Service’s conclusion that the Plan would not jeopardize the Utah prairie dog was unsupported because it assumed full habitat offset without requiring equivalent-value replacement or ensuring such comparisons would occur when counties/developers implemented the permits.
  • NEPA: The Service’s environmental assessment (and resulting “no significant impact” conclusion) was arbitrary and capricious because it relied on the same irrational assumption—full offset of impacts—without any required biological-value comparison of lost versus replacement habitat.
  • What the court upheld: The court upheld the Service’s (a) reliance on translocation as a preferred mitigation tool (as a scientific/technical judgment) apart from the biological-value-comparison defect; (b) approach to mitigation in minor development areas (conservation banks/easements/acquisitions); and (c) finding of adequate funding and flexible fee mechanisms.
  • Remedy: The court remanded and left vacatur-versus-remand to the district court in the first instance.

3. Analysis

A. Precedents Cited (and how they shaped the decision)

1) Standing and reviewability

  • Colo. Outfitters Ass'n v. Hickenlooper (de novo review of standing) set the appellate posture for reviewing the district court’s standing decision.
  • Friends of the Earth, Inc. v. Laidlaw Env't Servs. (TOC), Inc. (quoting Lujan v. Defenders of Wildlife) supplied the three-part standing test; the court applied it to Friends of Animals’ aesthetic/recreational injury (impeded ability to view Utah prairie dogs) and found traceability because the Plan was incorporated into, and functionally implemented through, the permits.
  • Summers v. Earth Island Inst. supported the associational-standing requirement that at least one member must have standing.

2) The APA “arbitrary and capricious” framework

  • Defs. of Wildlife v. U.S. Forest Serv. and Cure Land, LLC v. U.S. Dep't of Agric. confirmed that ESA and NEPA claims proceed through APA review in this circuit.
  • Motor Vehicle Mfrs. Ass'n of the U.S. v. State Farm Mut. Auto. Ins. provided the canonical list of “arbitrary and capricious” indicators and the requirement that the agency consider important aspects of the problem and provide a reasoned explanation.
  • W. Watersheds Project v. Haaland described the appellate court’s posture—reviewing the agency decision with the same deference as the district court.
  • Audubon Soc'y of Greater Denver v. U.S. Army Corps of Eng'rs and Utah Env't Cong. v. Russell were used to emphasize deference, especially in technical/scientific matters—an important backdrop to why the court accepted translocation as a general tool, yet still required a habitat-value comparison.
  • Dep't of Homeland Sec. v. Regents of the Univ. of Cal. reinforced the rule against “post hoc rationalizations,” limiting review to the Service’s stated reasons.

3) Deference to scientific/technical judgments—accepted and rejected

  • San Juan Citizens All. v. Stiles underpinned the court’s deference to the Service’s translocation protocols and evolving technical practices. The court relied on this deference to reject Friends of Animals’ attacks on translocation survival rates and success metrics, so long as the agency explained its approach.
  • Baltimore Gas & Elec. Co. v. Nat. Res. Def. Council, Inc. appeared in the NEPA discussion through the “frontiers of science” concept; the court stressed that the Service’s failure was not a difficult scientific frontier, but a basic analytic omission (no biological-value comparison).

4) ESA habitat protection and inconsistency over time

  • Sierra Club v. Marsh (and its partial abrogation recognized in Cottonwood Env't L. Ctr. v. U.S. Forest Serv.) was invoked to illustrate an ESA principle: agencies must ensure meaningful habitat protection/creation rather than merely assume replacement later. The Tenth Circuit used it to underscore the seriousness of authorizing habitat loss without ensuring equivalent-value replacement.

5) NEPA standards and judicial deference

  • Wyoming v. U.S. Dep't of Agric. (quoting Citizens' Comm. to Save Our Canyons v. Krueger) provided the “hard look” requirement.
  • Robertson v. Methow Valley Citizens Council supplied NEPA’s purpose: ensuring agencies carefully consider detailed information about significant impacts.
  • Seven Cnty. Infrastructure Coal. v. Eagle Cnty. (U.S. Supreme Court, 2025) drove the court’s articulation of “substantial deference” and the “broad zone of reasonableness” for NEPA significance determinations—including restraint regarding indirect effects. Yet, even under that deferential standard, the court found the Service’s assumption irrational.
  • WildEarth Guardians v. Conner and Hillsdale Env't Loss Prevent'n, Inc. v. U.S. Army Corps of Eng'rs guided the “degree to which the action affects” significance factors (not the mere existence of an effect).
  • WildEarth Guardians v. U.S. Bureau of Land Mgmt. supplied the principle that reliance on an irrational assumption renders NEPA analysis arbitrary/capricious.
  • Audubon Soc'y of Portland v. Haaland was cited for applying the NEPA regulations in effect at the time of the agency decision.
  • New Mexico ex rel. Richardson v. Bureau of Land Mgmt. and Colo. Env't Coal. v. Dombeck informed the alternatives discussion and the “flyspecks” principle—minor defects do not warrant reversal if NEPA’s informational goals are met.

6) Preservation, waiver, and prejudice

  • Rocky Mountain Wild v. Dallas (quoting WildEarth Guardians v. Nat'l Park Serv.) supported harmless-error/prejudice principles under the APA.
  • W. Watersheds Project v. U.S. Bureau of Land Mgmt. supported issue-exhaustion/forfeiture for arguments not raised in administrative proceedings.
  • United States v. Leffler was used to reject arguments first raised too late (e.g., reply brief or not preserved below).

7) Remedy (vacatur vs remand) discretion

  • Ctr. for Biological Diversity v. U.S. Env'l Prot. Agency provided the two-factor test for vacatur vs remand (seriousness/likelihood of justification; disruptive consequences).
  • Diné Citizens Against Ruining Our Env't v. Haaland and Devon Energy Prod. Co. v. U.S. Dep't of the Interior supported leaving this fact-intensive remedial balancing to the district court.

B. Legal Reasoning

1) The court’s central ESA holding: mitigation must replace “biological value,” not merely acreage or animals

The ESA allows incidental take only if the applicant will “minimize and mitigate the impact of the taking to the maximum extent practicable.” 16 U.S.C. § 1539(a)(2)(B)(ii). The Service concluded the Plan’s mitigation would “fully offset” habitat and prairie dog losses. The Tenth Circuit held that conclusion was arbitrary and capricious because the Service did not do (or require at any later stage) the essential comparative work: evaluating whether replacement habitat is of equivalent “biological value” to habitat being lost.

Critically, the opinion did not treat “habitat” as fungible. It emphasized that the Service’s own materials recognized that offsetting habitat loss requires asking “key questions” about the ecological function and suitability of replacement habitat (life-stage support, restoration lag time, uncertainties, climate suitability, and whether habitat type differs in value). Yet the Plan authorized takes without any requirement to compare old and new habitats—despite the Service’s acknowledgement that major development areas contained numerous medium/large colonies and “retain a high level of conservation value.”

2) Major development areas: the “inevitability” rationale was circular

The Service suggested colonies in major development areas would be lost anyway due to development and fragmentation. The Tenth Circuit called that reasoning circular because the Plan itself enabled future development via incidental take authorization. If major development areas are important (and the record described them as valuable and connected), the agency could not justify authorizing their loss by presuming that loss in advance—particularly without ensuring equivalent-value replacement.

3) Translocation: deference to scientific judgment, but not a substitute for habitat-value analysis

The court drew a sharp line between (a) the Service’s choice of translocation as a tool (a technical, experience-driven judgment entitled to deference) and (b) the legal adequacy of mitigation under the ESA, which required the agency to grapple with habitat quality/value. It accepted the Service’s explanation that translocation methods improved post-1985 and that “80%” of post-1985 translocation sites remained occupied, while also noting the low estimated survival rate and the Service’s explanations for it.

The key point: translocation may be permissible, but the Service cannot claim “full offset” while declining to evaluate whether the receiving habitats can functionally replace the lost habitats (especially where private lands may have higher densities than more arid federal lands).

4) Minor development areas and funding: flexible planning can be reasonable

In contrast, the court upheld the Service’s mitigation approach in minor development areas (conservation banks, easements, acquisitions) and its funding findings. The reasoning reflects administrative-law realism: agencies may rely on experience, historical contributions, and flexible fee schedules to manage uncertainty so long as the record supports a reasoned projection. The court accepted Utah’s history of funding (average $340,000 annually from 2005–2018), the Plan’s fee projections, and the Plan’s “changed circumstances” mechanism for adjustments.

5) Jeopardy/survival-and-recovery analysis failed for the same structural reason

The Service concluded the Plan would not reduce the likelihood of survival and recovery because impacts would be “fully offset.” But that assurance depended on an offset premise the agency did not operationalize. The opinion stressed the Service’s own 2012 recovery plan and the identification of “recovery units” as “essential to the conservation and recovery of the entire population.” Approving expected loss of substantial acreage within those units (e.g., 1,138 acres) without ensuring equivalent-value replacement left the Service with “no way to assure survival and recovery under the Plan.”

6) NEPA “hard look”: a FONSI cannot rest on unexamined mitigation assumptions

The Service’s environmental assessment found no significant impact largely because the prairie dog population was assumed not to decline given mitigation. The court held that assumption irrational: without any required comparison of old and new habitat biological value, there was no meaningful basis to conclude impacts would be fully offset. Even under the deference mandated by Seven Cnty. Infrastructure Coal. v. Eagle Cnty., the Service’s analysis fell outside the “broad zone of reasonableness” because it depended on a key unsupported premise.

C. Impact

1) A practical rule for ESA incidental take programs: “offset” means equivalent-value habitat replacement must be analyzed and required

The most consequential doctrinal move is the court’s insistence that ESA mitigation claims—especially programmatic plans using translocation and habitat substitution—must include (or mandate later) a comparative analysis of “biological value” between habitat lost and habitat provided. Agencies cannot approve a plan that authorizes take while postponing, or altogether omitting, the functional equivalence inquiry that makes “full offset” more than a label.

2) Constraints on “programmatic” planning

The Service attempted to characterize the Plan as a framework that did not itself authorize take, but the court treated the Plan/permits as integrated. Future conservation-plan architects in the Tenth Circuit should assume that if a plan sets the operative mitigation logic and authorizes take quantities, it must contain enforceable analytical and implementation hooks (e.g., habitat-value metrics, required equivalency findings, and oversight of county-issued certificates of inclusion).

3) NEPA significance determinations and mitigation

NEPA documents frequently rely on mitigation to support a FONSI. This opinion reinforces that mitigation-based FONSIs are vulnerable when the mitigation’s effectiveness is assumed rather than justified—especially where mitigation depends on the ecological interchangeability of habitats. Agencies should expect challenges if they do not define measurable criteria (here, “biological value” equivalence) and show how they will be applied before take occurs.

4) What survives: deference where the record shows expertise-based forecasting and adaptive mechanisms

The opinion is also a caution against overreading: it does not forbid translocation, stepped-up development projections, flexible fee schedules, or reliance on historical data. It instead demands that certain core ecological premises—habitat functional equivalence—be examined, not presumed.

4. Complex Concepts Simplified

  • Incidental take permit (ESA): Permission for otherwise lawful activity (e.g., development) that will unintentionally “take” a listed species, allowed only if the applicant meets statutory conditions. Here: 16 U.S.C. § 1539(a)(1)(B) and findings under § 1539(a)(2).
  • “Take”: Broadly defined to include harming, killing, trapping, capturing, or harassing a listed species. 16 U.S.C. § 1532(19).
  • Minimize and mitigate “to the maximum extent practicable”: The plan must reduce harm and provide mitigation as much as is realistically feasible—not merely offer aspirational measures.
  • Translocation: Trapping and moving animals from a development site to a new site. It can be a conservation tool, but it raises questions about survival, habitat suitability, and long-term colony persistence.
  • “Biological value” of habitat: Not a formal statutory term, but used here to mean the habitat’s functional/ecological worth for the species (e.g., food, soils, connectivity, life-stage support). The court required comparison of the value of what is lost versus what is provided.
  • Conservation banks / easements: Banks are permanently protected and managed lands generating “credits” for impacts; easements are deed restrictions that protect habitat on private land.
  • NEPA environmental assessment (EA) vs environmental impact statement (EIS): An EA is a shorter document used to decide whether impacts are significant; an EIS is required for major actions significantly affecting the environment. A “FONSI” ends the process at the EA stage.
  • APA “arbitrary and capricious”: A court does not re-decide policy; it checks whether the agency examined important issues, used reasoned decisionmaking, and connected evidence to conclusions.

5. Conclusion

Friends of Animals v. U.S. Fish and Wildlife Service establishes a durable administrative-law constraint on ESA/NEPA wildlife permitting in the Tenth Circuit: when an agency claims that mitigation will “fully offset” habitat loss—especially through translocation and substitution—it must compare (or require a later, enforceable comparison of) the “biological value” of habitat destroyed versus habitat provided. Without that comparative foundation, both ESA compliance findings (mitigation and no-jeopardy) and NEPA significance determinations can be arbitrary and capricious.

At the same time, the court preserved room for expert-driven, adaptive conservation planning: it deferred to the Service’s scientific choice of translocation as a tool and upheld funding determinations grounded in historical practice and flexible mechanisms. The result is not hostility to programmatic conservation plans, but a demand that their core ecological assumptions be translated into enforceable analyses—before the authorized take occurs.