United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued September 11, 2017 Decided November 7, 2017

No. 16-5282

TIMOTHY MAYO,

APPELLEE

KENT NELSON,

APPELLANT

v.

MICHAEL T. REYNOLDS, IN HIS OFFICIAL CAPACITY AS ACTING 

DIRECTOR OF THE U.S. NATIONAL PARK SERVICE, ET AL.,

APPELLEES

Appeal from the United States District Court

for the District of Columbia

(No. 1:14-cv-01751)

Eric R. Glitzenstein argued the cause for appellant. With 

him on the briefs was Katherine A. Meyer.

Rachel Heron, Attorney, U.S. Department of Justice, 

argued the cause for federal appellees. With her on the brief 

were Jeffrey H. Wood, Acting Assistant Attorney General, 

and Andrew Mergen, J. David Gunter II, and Judith Coleman, 

Attorneys.
2

Erik E. Petersen, Assistant Attorney General, Office of 

the Attorney General for the State of Wyoming, argued the 

cause for intervenor-appellee State of Wyoming. With him on 

the brief was James Kaste, Senior Assistant Attorney General.

Douglas S. Burdin, Anna M. Seidman, and Jeremy E. 

Clare were on the brief for intervenor-appellee Safari Club 

International.

Before: MILLETT, Circuit Judge, and EDWARDS and 

WILLIAMS, Senior Circuit Judges.

Opinion for the Court filed by Senior Circuit Judge

EDWARDS.

EDWARDS, Senior Circuit Judge: This case involves a 

challenge to decisions made by the National Park Service 

(“Park Service”) authorizing recreational hunting of elk in 

Wyoming’s Grand Teton National Park (“Grand Teton”). 

Appellant claims that the Park Service violated the National 

Environmental Policy Act (“NEPA”) by authorizing 

recreational hunts each year without first conducting a NEPA 

review to assess whether and to what extent hunting was in 

fact necessary for the proper management and protection of 

the elk. Appellant’s Br. 26. 

Grand Teton and the National Elk Refuge (“Refuge”) are 

home to the “Jackson herd,” one of the largest concentrations 

of elk in North America. Two federal agencies share primary 

responsibility for managing the Jackson herd: the Park 

Service, which has jurisdiction over Grand Teton, and the 

U.S. Fish and Wildlife Service (“FWS”), which manages the 

Refuge. In 2007, the two agencies, acting together, adopted a 

fifteen-year plan (“2007 Plan”) to manage the Jackson herd. 

The 2007 Plan set objectives to reduce the population size of
3

the herd, limit their risk of disease, and conserve their habitat.

In conjunction with the 2007 Plan, the agencies also issued a 

final environmental impact statement (“EIS”), as required by 

NEPA.

The 2007 Plan analyzed six alternative long-term 

strategies for managing the Jackson herd. The EIS, in turn,

carefully assessed the environmental risks posed by the 

alternative strategies. In the end, the agencies adopted an elkreduction program pursuant to which the Park Service would 

authorize elk hunting as needed to attain the Plan’s population 

objectives. The program also contemplated that the FWS 

would reduce supplemental feed given to the elk during 

winter months on the Refuge. Between 2007 and 2015, the 

Park Service adhered to the elk-reduction program in 

determining the number of elk authorized to be harvested and 

the number of hunters deputized to participate in a hunt. As a 

result, from 2007 to 2015, the size of the herd decreased, as 

did the number of deputized hunters and the number of elk 

authorized to be harvested. During this same period, however, 

the FWS failed to meet the 2007 Plan’s objective to wean the 

herd from supplemental feed.

Kent Nelson and Timothy Mayo, wildlife photographers, 

filed suit in the District Court challenging the Park Service’s

2015 program for elk hunting. See Mayo v. Jarvis, 177 F. 

Supp. 3d 91, 107–24 (D.D.C. 2016). They argued that the 

Park Service was required to prepare a new NEPA analysis 

every year that it implemented the fifteen-year elk-reduction 

program, disclosing and analyzing the unique environmental 

effects of each year’s hunt. Because no such analysis was 

done for the 2015 hunt authorization, they claimed that the 

Park Service’s action violated NEPA. Appellants also 

contended that the FWS’s failure to reduce supplemental 

feeding in line with the Plan’s goals necessitated the 
4

preparation of a supplemental EIS. However, supplemental 

feeding is managed by the FWS and Nelson and Mayo did not 

seek to pursue any action against the FWS with respect to that 

program. With respect to the NEPA claims, the District Court 

denied the plaintiffs’ summary judgment motion and granted 

the Park Service’s cross-motion for summary judgment. Id. at 

146. Nelson, but not Mayo, now appeals the District Court’s 

judgments. 

In its brief to this court, the Park Service cogently 

explains why the judgment of the District Court should be 

affirmed: 

Under NEPA, an agency must take a hard look at 

the environmental impacts of its proposed actions. The 

statute does not, however, require the agency to take a 

new look every time it takes a step that implements a 

previously-studied action, so long as the impacts of that 

step were contemplated and analyzed by the earlier 

analysis. Here, the Park Service’s 2007 Management 

Plan contemplated that the Park Service would 

authorize annual elk-reduction programs, and the 2007 

EIS accompanying that plan specifically analyzed the 

effects of such programs. . . . [Appellant] has not 

identified any impact from the 2015 reduction program 

that was not studied in the 2007 EIS . . . . The Park 

Service has therefore satisfied NEPA.

Appellees’ Br. 24. We agree. We therefore affirm the District 

Court’s judgment on the NEPA issues.

In the District Court, the plaintiffs also claimed that the 

agencies’ consultation over the effects of the elk-reduction 

program on the grizzly bear population did not satisfy the 

requirements of the Endangered Species Act (“ESA”). All 
5

parties agree that this claim is now moot because the grizzly 

bear is no longer listed as a threatened species under the ESA. 

See Endangered Species and Threatened Wildlife and Plants, 

82 Fed. Reg. 30,502 (June 30, 2017) (to be codified at 50 

C.F.R. pt. 17). We therefore vacate the District Court’s 

judgment on the ESA claim. See United States v. 

Munsingwear, Inc., 340 U.S. 36, 39–40 (1950).

I. BACKGROUND

A. Statutory and Regulatory Background

1. National Environmental Policy Act

Congress enacted the National Environmental Policy Act 

(“NEPA”) in part “to promote efforts which will prevent or 

eliminate damage to the environment and biosphere and . . . 

enrich the understanding of the ecological systems and natural 

resources important to the Nation.” 42 U.S.C. § 4321 (2012). 

To those ends, NEPA requires all federal agencies to include 

a detailed environmental impact statement (“EIS”) “in every 

recommendation or report on . . . major Federal actions 

significantly affecting the quality of the human environment.”

Id. § 4332(2)(C). This process ensures that an agency will

“consider every significant aspect of the environmental 

impact of a proposed action” and “inform the public” of its

analysis. Balt. Gas & Elec. Co. v. Nat. Res. Def. Council, Inc., 

462 U.S. 87, 97 (1983); see also Dep’t of Transp. v. Pub. 

Citizen, 541 U.S. 752, 768 (2004). “In other words, agencies 

must ‘take a hard look at [the] environmental consequences’

of their actions, and ‘provide for broad dissemination of 

relevant environmental information.’” Pub. Emps. for Envtl. 

Responsibility v. Hopper, 827 F.3d 1077, 1082 (D.C. Cir. 

2016) (quoting Robertson v. Methow Valley Citizens Council, 

490 U.S. 332, 350 (1989)) (internal quotation marks omitted).
6

Not every agency action requires the preparation of a full 

EIS, however. See, e.g., Duncan’s Point Lot Owners Ass’n 

Inc. v. FERC, 522 F.3d 371, 376 (D.C. Cir. 2008) (“[F]ederal 

control and responsibility for an action is not enough to 

trigger the EIS requirement.”). Thus, in determining whether 

a major federal action “significantly affect[s]” the 

environment, 42 U.S.C. § 4332(2)(C), an agency may prepare 

a more concise environmental assessment (“EA”), see

Council on Environmental Quality (“CEQ”) regulations, 40 

C.F.R. § 1508.9, which may result in the agency issuing a 

“finding of no significant impact” in lieu of a full EIS, see id.

§ 1508.13.

Where NEPA analysis is required, its role is “primarily 

information-forcing.” Sierra Club v. FERC, 867 F.3d 1357, 

1367 (D.C. Cir. 2017). As the Supreme Court has explained, 

“[t]here is a fundamental distinction . . . between a 

requirement that mitigation be discussed in sufficient detail to 

ensure that environmental consequences have been fairly 

evaluated, on the one hand, and a substantive requirement that 

a complete mitigation plan be actually formulated and 

adopted, on the other.” Robertson, 490 U.S. at 352. “NEPA is 

‘not a suitable vehicle’ for airing grievances about the 

substantive policies adopted by an agency, as ‘NEPA was not 

intended to resolve fundamental policy disputes.’” Grunewald 

v. Jarvis, 776 F.3d 893, 903 (D.C. Cir. 2015) (quoting Found.

on Econ. Trends v. Lyng, 817 F.2d 882, 886 (D.C. Cir. 1987)).

It is now well-established that “NEPA imposes only 

procedural requirements on federal agencies with a particular 

focus on requiring agencies to undertake analyses of the 

environmental impact of their proposals and actions.” Pub. 

Citizen, 541 U.S. at 756–57; see also Vt. Yankee Nuclear 

Power Corp. v. Nat. Res. Def. Council, Inc., 435 U.S. 519, 
7

558 (1978) (NEPA’s mandate “is essentially procedural”). It

is equally clear that NEPA does not impose a duty on 

agencies “to include in every EIS a detailed explanation of 

specific measures which will be employed to mitigate the 

adverse impacts of a proposed action.” Robertson, 490 U.S. at 

353 (emphasis omitted) (internal quotation omitted).

An agency is required to supplement an existing EIS only 

if the agency “makes substantial changes in the proposed 

action that are relevant to environmental concerns,” or if there 

are “significant new circumstances or information relevant to 

environmental concerns and bearing on the proposed action or 

its impacts.” CEQ regulations, 40 C.F.R. § 1502.9(c). Under 

this standard, an agency is not required to make a new 

assessment under NEPA every time it takes a step that 

implements a previously studied action, so long as the impacts 

of that step were contemplated and analyzed by the earlier 

analysis. See, e.g., Wyoming v. U.S. Dep’t of Agric., 661 F.3d 

1209, 1257–58 (10th Cir. 2011). 

In Marsh v. Oregon Natural Resources Council, 490 U.S. 

360 (1989), the Supreme Court explained that under the “rule 

of reason,” “an agency need not supplement an EIS every 

time new information comes to light after the EIS is 

finalized.” Id. at 373. Rather, “a supplemental EIS must be 

prepared” only when a new action will affect the quality of 

the environment “in a significant manner or to a significant 

extent not already considered.” Id. at 374; see also Nat’l 

Comm. for the New River, Inc. v. FERC, 373 F.3d 1323, 1330 

(D.C. Cir. 2004) (explaining that a supplemental impact 

statement is “only required where new information provides a 

seriously different picture of the environmental landscape”

(quoting City of Olmsted Falls v. Fed. Aviation Admin., 292 

F.3d 261, 274 (D.C. Cir. 2002))); Davis v. Latschar, 202 F.3d 

359, 369 (D.C. Cir. 2000) (requiring a supplemental impact 
8

statement only for “changes that cause effects which are 

significantly different from those already studied”). And 

because an agency’s decision whether to prepare a 

supplemental EIS requires “substantial agency expertise,” 

courts must defer to the agency’s “informed discretion.”

Marsh, 490 U.S. at 366–77.

2. The 2007 Elk-Management Plan and Environmental 

Impact Statement

As noted above, the Park Service and Fish and Wildlife 

Service jointly manage the Jackson elk herd. In the spring and 

summer, the Jackson herd tends to reside primarily in 

Wyoming’s Grand Teton National Park, under the jurisdiction 

of the Park Service. In the winter, however, much of the herd 

migrates to the neighboring National Elk Refuge, which is 

managed by the FWS. 

Since 1955, the Park Service has annually authorized the 

hunting of elk in the Park. Although hunting is frequently 

prohibited in national parks, Congress authorized the practice 

in Grand Teton in 1950 when it established the Park in its 

current form. See Pub. L. 81-787 § 6(a), 64 Stat. 849, 851–52 

(1950), codified at 16 U.S.C. § 673c. Specifically, Congress 

required the Park Service and Wyoming Game and Fish 

Commission to “devise . . . a program to insure the permanent 

conservation of the elk within the Grand Teton National Park”

and directed that such conservation program “shall include the 

controlled reduction of elk in such park, . . . when it is found 

necessary for the purpose of proper management and 

protection of the elk.” 16 U.S.C. § 673c(a). 

Part of the Park Service’s justification for the elk-hunting 

program has to do with the practices of the FWS on the 

Refuge. The FWS provides supplemental feed to elk on the 
9

Refuge during winter months on the assumption that there is 

an insufficient amount of winter range to support the numbers 

of elk that occupy the Jackson Hole area. This practice 

reduces incidents of elk starvation, but it also creates 

“significant problems” of its own. Defs. of Wildlife v. Salazar, 

651 F.3d 112, 113 (D.C. Cir. 2011). Supplemental feeding 

artificially increases the size and density of the elk herd, and it 

has also contributed to the spread of disease among the elk 

and erosion of their habitat. Id. at 113–14. Authorized hunting 

offsets some of the adverse effects of supplemental feeding by 

containing the herd’s population size, while also managing

the gender and age distributions of the Jackson elk herd.

In 2007, the Park Service and the FWS adopted a fifteenyear plan for managing the Jackson elk herd and prepared an 

EIS to assess the environmental effects of the plan. See Final 

Bison and Elk Management Plan and Environmental Impact 

Statement for the National Elk Refuge/Grand Teton National 

Park/John D. Rockefeller, Jr., Memorial Parkway (Feb. 1, 

2007) (“2007 Plan and EIS”), available at

http://bisonandelkplan.fws.gov. The Plan listed four goals for 

managing the elk: (1) conserving their habitat, (2) making the 

population sustainable, (3) contributing to Wyoming’s 

population objectives for the elk, and (4) managing the risk of

disease. Id. at ix. To achieve those ends, the agencies 

analyzed six alternative management programs, each of which 

varied in terms of its goals for the elk reduction level sought, 

the number of elk wintering on the Refuge, the use of hunting 

to control the population, and the extent to which 

supplemental feeding would continue on the Refuge. See id.

at ix–x.

The agencies chose a program denominated Alternative 

Four. That option called for reducing the total number of elk 

in the Jackson herd from approximately 13,000 to 11,000, and 
10

the number of elk wintering on the Refuge, where 

supplemental feed is served, from 6,800 down to 5,000. Id. at 

48. The Plan aimed to meet these targets through an “adaptive 

management approach” involving public education, habitat 

conservation, and a decreasing use of supplemental feeding 

“based on established criteria and changing social, political, 

or biological conditions.” Id. at 48, 65. In addition, the 

agencies assumed that hunting would be authorized “on the 

refuge, and when necessary . . . in the park, to assist the state 

in managing herd sizes, sex and age ratios, and summer 

distributions” of elk. Id. at 48. Specifically, the 2007 Plan 

predicted that in Grand Teton over the “long term an 

estimated average of 232–287 elk per year would be 

harvested by 773–957 deputized hunters, compared to 

baseline figures of 1,600 hunters and 480 elk per year.” Id. at 

472.

As noted above, the Park Service and the FWS also 

prepared an environmental impact statement in conjunction 

with the 2007 Plan, as required by NEPA. The final EIS 

carefully addressed the impact of the Plan’s six alternatives –

including the preferred elk-reduction program – on, inter alia, 

the Park and Refuge’s physical environment, id. at 194–210, 

the habitat of the elk, id. at 211–54, other wildlife, including 

threatened and endangered species, id. at 351–66, human 

health and safety, id. at 443–56, and recreational and tourism 

related activities, id. at 457–93. Importantly, the EIS noted 

that “[t]he level of analysis [in the report was] sufficient to 

allow several management actions to be carried out without 

having to complete additional environmental analyses (e.g.,

environmental assessments) prior to implementation.” Id. at 

191.

The 2007 Plan also was required to comply with the 

Endangered Species Act (“ESA”) due to the Plan’s potential 
11

to affect the Greater Yellowstone Ecosystem (“GYE”) 

population of grizzly bears, see id. at 351, a species that had 

been listed as “threatened” since 1975, see Amendment 

Listing the Grizzly Bear of the 48 Coterminous States as a 

Threatened Species, 40 Fed. Reg. 31,734 (July 28, 1975). 

Accordingly, the Park Service consulted with the FWS over 

the matter. The FWS then issued a biological opinion 

determining that the implementation of the 2007 Plan’s 

preferred alternative was not likely to jeopardize the existence 

of the grizzly bear, but might result in some take of grizzlies 

by elk hunters. See Bison and Elk Management Plan: National 

Elk Refuge and Grand Teton National Park (Apr. 2007), 

Appendix E, at 171–98, reproduced at J.A. 645–72, 830–61, 

available at https://www.fws.gov/bisonandelkplan/. In 2012, 

an elk hunter killed a grizzly bear, prompting the Park Service

to consult again with the FWS. In 2013, the FWS issued an 

addendum to its 2007 biological opinion, estimating that a 

total of five grizzly bears would be taken in the Park during 

the fifteen-year period covered by the 2007 Plan. 

Memorandum from Field Supervisor, U.S. FWS to 

Superintendent, Nat’l Park Service (Sept. 13, 2013), 

reproduced at J.A. 867–904, 870. 

B. Procedural Background

The Park Service has authorized elk hunting in Grand 

Teton in reliance on its 2007 Plan and EIS in every year since 

the Plan was adopted. On October 20, 2014, local wildlife 

photographers Timothy Mayo and Kent Nelson brought suit 

in the District Court, challenging the annual hunting 

authorizations as contrary to the Grand Teton National Park 

Act (“Enabling Act”), 16 U.S.C. § 673c(a), National Park 

Service Organic Act (“Organic Act”), 16 U.S.C. § 1, 

Administrative Procedure Act (“APA”), 5 U.S.C. § 706(2), 

ESA, 16 U.S.C. § 1531, and NEPA, 42 U.S.C. § 4321 et seq.
12

Complaint for Declaratory and Injunctive Relief, ¶¶ 68–80, 

reproduced at J.A. 33–37. On July 1, 2015, the plaintiffs filed 

a supplemental complaint, incorporating by reference each of 

the statutory claims to also apply to the Park Service’s 2015 

authorization of elk hunting in the Park. Supp. Complaint, 

¶¶ 1–8, J.A. 39–41. The State of Wyoming and Safari Club

International intervened as defendants before the District 

Court. Mayo, 177 F. Supp. 3d at 105.

With respect to their NEPA claims, the plaintiffs argued 

that the Park Service was required to issue a new EA or EIS 

every year during the fifteen-year term of the elk-reduction 

program. Complaint, ¶¶ 73–74, J.A. 35; Mayo, 177 F. Supp. 

3d at 107. They contended that changes had occurred after the 

agency promulgated the 2007 Plan and EIS – most notably, 

the FWS’s continued use of supplemental feeding on the 

Refuge – necessitating a supplemental EIS. Mayo, 177 F. 

Supp. 3d at 117, 122. 

The plaintiffs also challenged the biological opinion and 

its 2013 addendum as arbitrary and capricious for failing to 

address the possibility that elk viscera left by hunters “harass”

grizzly bears within the meaning of the ESA’s take 

prohibition. Id. at 142–45. As explained above, this claim is 

now moot, so it will not be addressed in this opinion.

Mayo and Nelson moved for summary judgment on July 

21, 2015. The Park Service, FWS, and intervenors opposed 

that motion and cross-moved for summary judgment in their 

favor.

On March 29, 2016, the District Court entered summary 

judgment for the government on the Enabling Act, Organic 

Act, and NEPA claims. Id. at 91, 146. With respect to the 

NEPA claims, the District Court held that the Park Service 
13

could rely on the 2007 EIS in making its annual elk-reduction 

decisions because that document “took the requisite ‘hard 

look’ at the potential environmental effects that might result 

from continuing the elk reduction program in the Park as a 

method of managing the herd.” Id. at 109. The District Court 

rejected the plaintiffs’ contention that the agencies had 

abandoned the 2007 Plan, and held that a supplemental EIS 

was not required since the record lacked evidence that the

FWS’s supplemental feeding practices “on the Refuge [have] 

had a spillover effect on the environmental impacts of elk 

hunting in the Park.” Id. at 122.

Accordingly, on August 1, 2016, the District Court 

entered final judgment on all counts in the government’s 

favor. Mayo v. Jarvis, 203 F. Supp. 3d 31, 42 (D.D.C. 2016). 

Kent Nelson, but not Timothy Mayo, has now appealed the 

denial of his motion for summary judgment and the entry of 

judgment for Appellees.

I. ANALYSIS

A. Standard of Review

We review the District Court’s grant and denial of 

summary judgment de novo. Theodore Roosevelt Conserv. 

P’ship v. Salazar, 661 F.3d 66, 72 (D.C. Cir. 2011). 

Because NEPA does not provide a private right of action, the 

agencies’ compliance with NEPA is reviewed under the

Administrative Procedure Act (“APA”) “and its deferential 

standard of review.” Sierra Club, 867 F.3d at 1367. 

The APA requires that we “hold unlawful and set aside 

agency action” that is “arbitrary, capricious, an abuse of 

discretion, or otherwise not in accordance with law.” 5 U.S.C. 

§ 706(2)(A). Agency action is arbitrary and capricious “if the 
14

agency has relied on factors which Congress has not intended 

it to consider, entirely failed to consider an important aspect 

of the problem, [or] offered an explanation for its decision 

that runs counter to the evidence before the agency.” Motor 

Vehicle Mfrs. Ass’n v. State Farm Mut. Auto. Ins. Co., 463 

U.S. 29, 43 (1983); see also Duncan’s Point Lot Owners, 522 

F.3d at 376 (“We will overturn an agency’s decision not to 

prepare an EIS only if that decision was arbitrary, capricious, 

or an abuse of discretion.”). In evaluating whether the agency 

has met this standard, the court must “not . . . substitute its 

[own] judgment for that of the agency.” State Farm, 463 U.S. 

at 43. 

As noted above, the Supreme Court has emphasized that 

“inherent in NEPA and its implementing regulations is a ‘rule 

of reason.’” Pub. Citizen, 541 U.S. at 767 (quoting Marsh, 

490 U.S. at 373). The rule of reason governs our review of an 

agency’s environmental analysis, N. Slope Borough v. 

Andrus, 642 F.2d 589, 600 (D.C. Cir. 1980), decision not to 

prepare a NEPA analysis, Pub. Citizen, 541 U.S. at 767, and 

decision not to supplement an existing EIS, Marsh, 490 U.S. 

at 373–74. The standard “ensures that agencies determine 

whether and to what extent to prepare an EIS based on the 

usefulness of any new potential information to the 

decisionmaking process.” Pub. Citizen, 541 U.S. at 767; see 

also Marsh, 490 U.S. at 373–74. “The overarching question is 

whether an EIS’s deficiencies are significant enough to 

undermine informed public comment and informed 

decisionmaking.” Sierra Club, 867 F.3d at 1368 (citing 

Nevada v. Dep’t of Energy, 457 F.3d 78, 93 (D.C. Cir. 2006)).

A court’s “role in reviewing an agency’s decision not to 

prepare an EIS is a ‘limited’ one, ‘designed primarily to 

ensure that no arguably significant consequences have been 

ignored.’” Myersville Citizens for a Rural Cmty., Inc. v. 
15

FERC, 783 F.3d 1301, 1322 (D.C. Cir. 

2015) (quoting TOMAC v. Norton, 433 F.3d 852, 860 (D.C. 

Cir. 2006)). Necessarily, then, “[w]here the preparation of an 

EIS would serve ‘no purpose’ in light of NEPA’s regulatory 

scheme as a whole, no rule of reason worthy of that title 

would require an agency to prepare an EIS.” Pub. Citizen, 541 

U.S. at 767 (internal quotation marks omitted).

B. Appellant’s Claim Regarding the Need for an Annual 

NEPA Assessment

Appellant’s primary argument on appeal is that each 

annual hunting authorization constitutes a “major Federal 

action” that triggers NEPA’s mandate that the agency prepare 

an EA or EIS. 42 U.S.C. § 4332(2)(C); see CEQ regulations, 

40 C.F.R. § 1508.18 (defining “Federal action” to include 

“continuing activities” and approvals by federal agencies of 

“specific projects, such as . . . management activities located 

in a defined geographic area” and “actions approved by 

permit”); id. § 1508.27 (defining “significantly”). Appellant 

offers three arguments in support of his claim that the 2007 

EIS cannot satisfy this statutory requirement: (1) the 2007 

Plan did not disclose the particulars of each future annual 

hunt; (2) the agencies have stopped implementing the Plan; 

and (3) significant new information bearing on the 

environmental effects of hunting have never been analyzed.

Intervenor-Appellee Wyoming argues that the Park 

Service’s authorization of the 2015 elk-reduction program is 

not a “major Federal action” since it is “simply one step in the 

agency’s ongoing management of the elk and bison herds 

under the fifteen-year term of the 2007 Plan.” Wyoming’s Br. 

34. The Park Service, in turn, contends that even if each 

hunting authorization is a “major Federal action” which may 

“significantly affect” the environment, the 2007 EIS relieved 
16

the Park Service of the obligation to prepare fresh NEPA 

documentation each year it implements the elk-reduction 

program in conformity with the 2007 Plan. Appellees’ Br. 28–

44. We agree with the Park Service.

Once an agency has taken a “hard look” at “every 

significant aspect of the environmental impact” of a proposed 

major federal action, Balt. Gas, 462 U.S. at 97 (quoting Vt. 

Yankee, 435 U.S. at 553), it is not required to repeat its 

analysis simply because the agency makes subsequent 

discretionary choices in implementing the program. As 

discussed above in part I.A, an agency may rely on an

already-performed, “thorough and comprehensive” NEPA 

analysis. New York v. U.S. Nuclear Regulatory Comm’n (New 

York II), 824 F.3d 1012, 1019 (D.C. Cir. 2016).

In this case, the Park Service published a thorough and

detailed EIS in 2007. Appellant has identified no significant 

way in which the subsequent hunting authorizations deviated 

from the assessment made in 2007. NEPA does not impose a 

duty on agencies “to include in every EIS a detailed 

explanation of specific measures which will be employed to 

mitigate the adverse impacts of a proposed action.” 

Robertson, 490 U.S. at 353 (internal quotation marks and 

emphasis omitted). And an agency is not required to make a 

new assessment under NEPA every time it takes a step that 

implements a previously studied action. See Marsh, 490 U.S. 

at 373. So long as the impacts of the steps that the agency 

takes were contemplated and analyzed by the earlier NEPA 

analysis, the agency need not supplement the original EIS or 

make a new assessment. See Nat’l Comm. for the New River, 

373 F.3d at 1330. The 2007 EIS was clearly sufficient to 

cover elk hunting during the ensuing fifteen years under the 

2007 Plan absent a material change causing unforeseen 

environmental consequences. 
17

1. Adequacy of the 2007 EIS

In preparing the 2007 EIS, the agencies took a hard look 

at the potential environmental effects of the program to 

reduce the Jackson elk herd through annual hunting 

determinations. Spanning more than 600 pages, the EIS

analyzed the effects of elk hunting on a variety of relevant 

environmental factors. For example, the EIS described how 

the elk-reduction program would likely affect the elks’

mortality potential, see 2007 Plan and EIS at 258, 296, the 

overall size of the Jackson herd, and the concomitant ability 

of the Park Service to accomplish the Plan’s population goals 

for the elk, see id. at 466–67, 471–72. The EIS considered the 

effect of hunting on the density of the herd and distribution of 

the elk throughout the Park and Refuge, id. at 288–90, as well 

as on calving, age, and sex ratios of the elk, id. at 294–95. The 

EIS additionally explained how hunting might affect the elks’

social practices, potentially increasing the elks’ “nervousness, 

energetic expenditures, and possibly decreasing nutrition 

because of reductions in foraging.” Id. at 291.

The EIS also took into account the elk-reduction 

program’s likely consequences on other wildlife, including 

various amphibians, id. at 434, as well as mule deer, moose, 

and pronghorn and bighorn sheep, e.g., id. at 399, 377–78. It 

specifically addressed the effects of hunting on species listed 

under the ESA, such as the grizzly bear, describing how the 

presence of hunters in particular hunting areas within the Park 

and the changing scope of the hunt over time might impact 

such species. Id. at 353. For example, the EIS considered the 

possibility that elk hunters might kill grizzly bears, id. at 357,

and, more optimistically, produce an additional source of 

nutrition for grizzlies, wolves, and bald eagles by creating elk 

“gut piles” for the animals to scavenge, id. at 359.
18

In addition, the EIS considered the elk-reduction 

program’s relation to the region’s human environment. It 

evaluated the likelihood that hunting would cause injury, id.

at 449, increase the risk of traffic accidents, id. at 448–49, and 

reduce visitors’ opportunities to observe the elk, id. at 462–

64, including for purposes of wildlife photography, id. at 457–

58. The EIS further explained that by bringing people into 

proximity with the elk, hunting might increase the risk that 

humans catch diseases from the animals. Id. at 449, 451.

The EIS analyzed more than just the environmental effects 

of the elk-reduction program. It also evaluated alternative 

uses of hunting as an elk-management tool. For instance, it 

considered changing hunting practices by closing traditional 

hunting areas and opening non-traditional areas. Id. at 279–

80. It thoroughly discussed the possibility of eliminating 

hunting completely from the Park and Refuge. E.g., id. at 

265–68, 272–73, 321. And it contained a detailed discussion 

of possible mitigation measures where relevant to the 

environmental risks it identified.

All in all, given the level of detail in the assessment, there 

is no question that the 2007 EIS “adequately considered and 

disclosed the environmental impact of” the 2007 Plan’s 

preferred elk-reduction program, its necessity, and its 

alternatives. Nevada, 457 F.3d at 93 (quoting Balt. Gas, 462 

U.S. at 97–98).

This appeal does not involve an arbitrary and capricious 

challenge to the Park Service’s annual decisions to authorize 

elk hunting in Grand Teton. Instead, Appellant faults the Park 

Service for not preparing a NEPA analysis each year during 

the fifteen-year term of the 2007 Plan to document each 

“hunt’s timing, location, restrictions, and . . . potential 
19

alternatives for avoiding or minimizing impacts.” Appellant’s 

Br. 41. As we have already explained, what Appellant seeks is 

much more than is required by NEPA. The Park Service’s 

mere implementation of the 2007 Plan, without more, did not 

result in any “seriously different picture of the environmental 

landscape.” Nat’l Comm. for the New River, 373 F.3d at 1330. 

All the environmental effects seen during the years after the 

promulgation of the 2007 Plan and EIS had been anticipated 

and analyzed in the original environmental assessment. 

Therefore, the Park Service had no duty to prepare a 

supplemental or new EIS.

2. Agency Discretion to Determine When and How to 

Engage in NEPA Analysis

NEPA does not prevent an agency from satisfying future 

NEPA obligations by performing a NEPA analysis at the

outset of a long-term project. The decision in New York II,

824 F.3d at 1016, confirms this point. In that case, the 

Nuclear Regulatory Commission had prepared a “Generic 

Environmental Impact Statement” concerning the effects of 

on-site storage of spent nuclear fuel. The agency issued a rule 

that “incorporate[d] the findings of the [EIS] into all future 

reactor licensing proceedings,” id., and this court upheld that 

rule and EIS as lawful under NEPA, id. at 1016–23. 

Therefore, it is clear here that the agencies’ decision to adopt 

a fifteen-year plan supported by one EIS was permissible 

under NEPA. 

To be sure, agencies are not always free to comply with 

NEPA by issuing a single EIS at the outset of a long-term 

project. An environmental analysis that occurs too early in the 

planning process may lack “meaningful information”

necessary for informed consideration. Scientists’ Inst. for Pub. 

Info., Inc. v. Atomic Energy Comm’n, 481 F.2d 1079, 1093–
20

94 (D.C. Cir. 1973). Thus, if a program “involves . . . separate 

sub-projects and will take many years,” NEPA’s 

implementing regulations allow the agency to “evaluate[] 

each sub-project as it becomes ready” and tailor its 

subsequent analyses to particularized considerations not 

already addressed in a prior “programmatic EIS.” Nevada, 

457 F.3d at 91; see CEQ regulations, 40 C.F.R. § 1508.28. 

“Tiering” – as this process is known – is “appropriate when it 

helps the lead agency to focus on the issues which are ripe for 

decision and exclude from consideration issues already 

decided or not yet ripe.” CEQ regulations, 40 C.F.R. 

§ 1508.28(b) (emphasis added).

In Theodore Roosevelt Conservation Partnership v. 

Salazar, for example, the Bureau of Land Management 

approved drilling permits based on EAs that tiered to a 

programmatic EIS. 616 F.3d 497, 506 (D.C. Cir. 2010). 

Plaintiffs argued that the specific approvals were arbitrary and 

capricious because the underlying EIS used an outdated 

scientific method for measuring the project’s effects on ozone 

concentrations. Id. at 510–11. This court rejected that 

argument, stating, “[w]hile courts have required [EAs] to 

analyze certain impacts for the first time when the broader 

analysis did not address the impact in question at all, this is 

not such a case.” Id. at 512 (citation omitted). The earlier EIS 

already “address[ed] the impact drilling would have on ozone 

concentrations” and “[n]othing in the law requires agencies to 

reevaluate their existing environmental analyses each time the 

original methodologies are surpassed by new developments.”

Id.

Appellant claims that Theodore Roosevelt supports his 

argument. In that case, Appellant argues, the court rejected 

the plaintiffs’ challenges in part because the agency 

committed to performing an EA before approving any specific 
21

application to drill. Appellant’s Br. 42–45. That is true 

enough, as far as it goes. When an earlier impact statement 

fails to take a hard look at a component of a plan that is major 

and may itself significantly affect the environment, the 

agency must do so through an EA or EIS prior to taking the 

action. But Theodore Roosevelt expressly excused the agency 

from conducting subsequent environmental analyses of issues 

already thoroughly evaluated in the earlier impact statement. 

See 616 F.3d at 512. Under the rule of reason, subsequent 

“site-specific” NEPA analyses are required only for “those 

localized environmental impacts that were not fully evaluated 

in the program statement.” Scientists’ Inst. for Pub. Info., 481 

F.2d at 1093. When all relevant environmental issues have 

already been analyzed and decided, additional EAs or 

supplementation are not required.

Furthermore, it was for the Park Service to decide whether 

to perform the environmental analysis in a comprehensive EIS 

or in narrower annual documentation. In Natural Resources 

Defense Council, Inc. v. U.S. Nuclear Regulatory 

Commission, we explained that the agency, “in its discretion, 

could have chosen to explore alternatives to the particular 

tanks in either a ‘programmatic’ or ‘site-specific’ format.”

606 F.2d 1261, 1271 (D.C. Cir. 1979); see also Izaak Walton 

League of Am. v. Marsh, 655 F.2d 346, 374 n. 73 (D.C. Cir. 

1981) (“[T]he decision whether to prepare a programmatic 

impact statement is committed to the agency’s discretion.”).

Appellant has not shown that it was arbitrary and capricious 

for the Park Service to perform the required NEPA analysis in 

a single EIS.

3. Consistency of the Annual Hunts with the 2007 Plan 

and 2007 EIS’s Projections
22

The record indicates that the Park Service has 

implemented the elk-reduction program in the manner 

envisioned by the 2007 Plan and analyzed in the 2007 EIS. 

The Plan and EIS predicted that the number of deputized 

hunters in the Park would decline from an average of 1,600 

hunters per year to 773–957 and, over “the long term,” the 

number of elk harvested would decline from an average of 

480 elk per year to 232 to 287 elk per year. 2007 Plan and EIS 

at 472. Over the last ten years, the number of elk authorized to 

be hunted in the Park has declined from 600 to 300, with 

fewer hunters deputized to hunt elk in both the Park and 

Refuge combined than the Plan allowed for the Park alone. In 

sum, the record confirms that the Park Service’s elk hunting 

authorizations have been within the range of the Plan’s 

expectations, on which the 2007 EIS based its analysis.

Appellant’s argument that the agencies have abandoned 

the 2007 Plan has no merit. The record indicates only one 

implementation failure under the 2007 Plan – the FWS’s

failure to decrease supplemental feeding on the Refuge –

which is addressed below. However, the record also shows 

that the 2007 Plan as a whole – including its monitoring, 

education, adaptive management, and hunting programs – has 

been followed. Furthermore, as noted above, “NEPA is ‘not a 

suitable vehicle’ for airing grievances about the substantive 

policies adopted by an agency, as ‘NEPA was not intended to 

resolve fundamental policy disputes.’” Grunewald, 776 F.3d 

at 903 (quoting Found. on Econ. Trends, 817 F.2d at 886).

Therefore, Appellant’s policy preference for reduced 

supplemental feeding is beyond the scope of our review of his 

NEPA challenge. The agencies’ 2007 NEPA assessment 

satisfied the requirements of the law for the annual elk hunts. 

The subsequent failure of the FWS to cut back on 

supplemental feeding does not undermine this conclusion, 

especially when the record indicates that all of the potential 
23

environmental effects of the Plan were fully addressed in the 

2007 EIS and the principal policy objectives of the 2007 Plan 

are being met.

C. Appellant’s Challenge to the FWS’s Supplemental 

Feeding

The question remains whether the FWS’s failure to cut 

back on supplemental feeding is otherwise unlawful. 

Appellant makes much of the fact that the weaning of the herd 

from supplemental feeding was one of the methods adopted 

by the 2007 Plan to manage the population of the elk herd. 

And Appellant complains that, despite committing to working 

toward a “complete transition” away from supplemental feed 

to “free-standing forage” on the Refuge, the FWS’s 

supplemental feeding has continued on the Refuge and the 

number of elk wintering there has increased over the last ten 

years. Although the FWS never committed to ending 

supplemental feeding by any specific date, its failure to 

decrease supplemental feeding obviously is not in keeping 

with one of the goals of the Plan. See Defs. of Wildlife, 651 

F.3d at 117 (noting that “the agencies are committed to 

ending supplemental feeding”).

There are two glaring problems with Appellant’s 

complaint. First, as noted above, the failure of the FWS to cut 

back on supplemental feeding does not indicate that the 2007 

Plan has failed with respect to elk hunting. 

Second, as Appellant’s counsel conceded during oral 

argument before this court, this case does not directly 

challenge supplemental feeding. Oral Arg. Recording 37:00–

48. The Fish and Wildlife Service, not the Park Service, is 

responsible for the supplemental feeding program, which 

takes place on the Refuge, not in the Park. And Appellant has 
24

brought no viable legal action against the FWS to contest the 

supplemental feeding program. In an effort to overcome this 

problem, Appellant argues that the FWS’s failure to decrease

supplemental feeding represents a substantial change in the 

environmental consequences of the elk-reduction program 

requiring supplemental NEPA analysis. This is a clever claim, 

but it fails.

The heart of Appellant’s claim appears to be that if 

supplemental feeding is not reduced then hunting necessarily 

must continue in order to ensure that the size of the elk herd 

does not exceed the projections of the 2007 Plan. On this 

theory, Appellant argues that the Park Service must publish 

new NEPA analyses evaluating whether hunting continues to 

be necessary in light of the fact that supplemental feeding has 

not declined. We reject this argument. The EIS clearly and 

exhaustively contemplated the continuation of the elkreduction program over the life of the fifteen-year Plan. And 

while it is not implausible to assume that the Park Service 

might have authorized more hunting than the 2007 Plan 

contemplated because of the FWS’s failure to decrease

supplemental feeding, the record refutes this assumption.

As explained above, the Park Service’s implementation of 

the annual elk-reduction program has met the population

goals of the 2007 Plan and EIS. From 2007 to 2015, the size 

of the herd decreased, as did the number of deputized hunters

and the number of elk authorized to be harvested. In other 

words, the number of elk authorized to be harvested and the 

number of hunters deputized to participate in hunts did not 

increase as a result of the FWS’s continued use of 

supplemental feeding. Therefore, Appellant has failed to 

demonstrate any “substantial change[] in the proposed action”

– elk hunting in Grand Teton – “relevant to environmental 

concerns” or any “significant new circumstances or 
25

information relevant to environmental concerns and bearing 

on the proposed action or its impacts.” CEQ regulations, 40 

C.F.R. § 1502.9(c) (emphases added). 

We reiterate that, in reaching this conclusion, a crucial 

consideration here is the fact that the “proposed action”

challenged in this case is the Park Service’s authorization of 

elk hunting in Grand Teton, not the FWS’s supplemental 

feeding practices on the Refuge. The admitted variance 

between the Plan’s proposed supplemental feeding program 

and that program’s implementation simply does not 

“provide[] a seriously different picture of the environmental 

landscape” of hunting. Nat’l Comm. for the New River, 373 

F.3d at 1330 (quoting Olmsted Falls, 292 F.3d at 274). No 

supplementation is therefore required. See Marsh, 490 U.S. at

373 (“[A]n agency need not supplement an EIS every time 

new information comes to light after the EIS is finalized.”); 

Blue Ridge Envtl. Def. League v. Nuclear Regulatory 

Comm’n, 716 F.3d 183, 196 (D.C. Cir. 2013) (rejecting 

supplementation claim because the “[p]etitioners failed to 

indicate any environmental data that were not considered in 

the EIS”). 

If Appellant wishes to challenge the merits of the FWS’s 

supplemental feeding program, he will have to pursue an 

appropriate action against the FWS directly. 

III. CONCLUSION

For the reasons set forth above, we affirm the judgment of 

the District Court on the NEPA claims. We vacate the District 

Court’s judgment as to the ESA claim, which is now moot.

So ordered.