Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-caDC-14-05311/USCOURTS-caDC-14-05311-0/pdf.json

Nature of Suit Code: 893
Nature of Suit: Environmental Matters
Cause of Action: 

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United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued September 23, 2016 Decided March 3, 2017

No. 14-5300

DEFENDERS OF WILDLIFE, ET AL.,

APPELLEES

v.

RYAN ZINKE, IN HIS OFFICIAL CAPACITY AS SECRETARY OF

THE UNITED STATES DEPARTMENT OF THE INTERIOR, ET AL.,

APPELLANTS

STATE OF WYOMING, ET AL.,

APPELLEES

Consolidated with 14-5311, 14-5312, 14-5313, 14-5314,

14-5315

Appeals from the United States District Court

for the District of Columbia

(No. 1:12-cv-01833)

Joan M. Pepin, Attorney, U.S. Department of Justice,

argued the cause for Federal Appellants. With her on the briefs

were John C. Cruden, Assistant Attorney General, and David C.

Shilton, Attorney.

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Jay Jerde, Special Assistant AttorneyGeneral, Office of the

Attorney General for the State of Wyoming, argued the cause

for appellant State of Wyoming. Jeremiah I. Williamson,

Assistant Attorney General, entered an appearance.

John A. Sheehan was on the brief for amicus curiae

Wyoming Wolf Coalition-2013's in support of appellant State of

Wyoming. 

Timothy J. Preso argued the cause for appellees/crossappellants Defenders of Wildlife, et al. With him on the brief

was Ralph E. Henry, Jr.

Anna M. Seidman, Douglas S. Burdin, Jeremy S. Clare,

Michael T. Jean, and John I. Kittel were on the briefs for the

non-governmental defendant-intervenor-appellants/crossappellees. Christopher A. Conte entered an appearance. 

Before: ROGERS, BROWN and PILLARD, Circuit Judges.

Opinion for the Court filed by Circuit Judge ROGERS.

ROGERS, Circuit Judge: The gray wolf in Wyoming has

been a protected species since 1973 pursuant to the Endangered

Species Act (“ESA”) and its predecessor. In 2011, the Secretary

of the Interior proposed to delist the wolf on the basis of the

recovery of the Northern Rocky Mountain gray wolf population

and the conservation management plan of the State of Wyoming. 

Environmental groups opposed the delisting, and thereafter

Wyoming made statutory and regulatory changes and created an

Addendum to its management plan. Upon consideration of these

changes and other data, the Fish and Wildlife Service, acting on

the Secretary’s behalf, delisted the wolf in Wyoming as it had in

the adjacent states of Montana and Idaho. Removal of the Gray

Wolf in Wyoming From the Federal List of Endangered and

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Threatened Wildlife and Removal of the Wyoming Wolf

Population’s Status as an Experimental Population, 77 Fed.

Reg. 55,530 (Sept. 10, 2012) (the “Rule”). Environmental

groups sued, and the district court vacated the Rule, agreeing

that the Service had arbitrarily determined that Wyoming had

put into place adequate “regulatory mechanisms.” 16 U.S.C.

§ 1533(a)(1)(D). The court rejected the environmental groups’

other challenges to the Rule. 

The Secretaryand the State of Wyoming appeal, principally

on the ground that the district court erred by failing to defer to

the Service’s reasonable interpretation of “regulatory

mechanisms” to include the State’s management plan for a wolf

population buffer, which although not itself legally binding, is

a practical entailment of the State’s statutorypopulation minima. 

Environmental groups cross-appeal the district court’s

conclusions that the Rule includes adequate provisions on

genetic connectivity between wolf subpopulations and does not

imperil the wolves in a “significant portion” of their range. For

the following reasons, we reverse the judgment vacating the

Rule and otherwise affirm.

I.

Section 4(a)(1) of the ESA provides that the Secretary is to

determine whether a species is endangered or threatened because

of one or more of the following factors: 

(A) the present or threatened destruction, modification,

or curtailment of its habitat or range; (B)

overutilization for commercial, recreational, scientific,

or educational purposes; (C) disease or predation; (D)

the inadequacy of existing regulatory mechanisms; or

(E) other natural or manmade factors affecting its

continued existence. 

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16 U.S.C. § 1533(a)(1). This determination is to be made

“solely on the basis of the best scientific and commercial data

available . . . after taking into account those efforts, if any, being

made by any State . . . to protect such species, whether by

predator control, protection of habitat and food supply, or other

conservation practices, within any area under its jurisdiction.” 

Id. § 1533(b)(1)(A). A species — defined to include “any

distinct population segment . . . which interbreeds when

mature,” id. § 1532(16) — must be listed if its survival is

threatened or endangered “throughout all or a significant portion

of its range,” id. § 1532(6), (20). Section 4(f) requires the

Secretary to develop and implement recovery plans for all listed

species, id. § 1533(f)(1), incorporating “objective, measurable

criteria which, when met, would result in a determination . . .

that the species be removed from the list,” id.

§ 1533(f)(1)(B)(ii). Once the species has recovered sufficiently

to be delisted, Section 4(g) requires the Secretary, in cooperation

with the States, to monitor the species’ status “for not less than

five years.” Id. § 1533(g)(1). Additionally, the Secretary is

instructed to “make prompt use of the authority . . . to prevent a

significant risk to the well being of any such recovered species.” 

Id. § 1533(g)(2). By regulation, the Secretary has instructed that

upon listing a species the Fish and Wildlife Service (hereinafter,

“the Service”) shall develop and implement recovery plans

calling for “improvement in the status of listed species to the

point at which listing is no longer appropriate under the criteria

set out in section 4(a)(1) of the [ESA].” 50 C.F.R. § 402.02. 

The Northern Rocky Mountain gray wolf had by the 1930s

been extirpated from Montana, Idaho, and Wyoming by western

settlers who aggressively poisoned, trapped, and shot them. In

the 1980s, gray wolves from Canada began to colonize

northwestern Montana. In 1995 and 1996, 35 wolves from

Alberta and British Columbia were reintroduced in Central

Idaho, and 31 more were reintroduced in Yellowstone National

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Park, virtually all of which is in northwestern Wyoming. The

Service set recovery goals for Montana, Idaho, and Wyoming 

of at least 10 breeding pairs and 100 wolves, for a total Northern

Rocky Mountain population of at least 30 breeding pairs and

300 wolves, with adequate genetic connectivity between the

three subpopulations (i.e., at least one migrant per generation

that disperses from one subpopulation to another and

successfully breeds). 76 Fed. Reg. 61,782, 61,791, 61,814 (Oct.

5, 2011) (“NPRM”). 

The Service designated the Northern Rocky Mountain gray

wolf as a distinct population segment in 2008, and proposed in

2009 to delist the wolf in Montana and Idaho. Following

various court challenges and intervention by Congress, that

delisting occurred in 2011. Reissuance of Final Rule to Identify

the Northern Rocky Mountain Population of Gray Wolf as a

Distinct Population Segment and to Revise the List of

Endangered and Threatened Wildlife, 76 Fed. Reg. 25,590 (May

5, 2011); see also All. for the Wild Rockies v. Salazar, 672 F.3d

1170, 1171–72 (9th Cir. 2012). In proposing delisting in

Wyoming in 2011, the Service recounted the characteristics and

history of the gray wolf. NPRM, 76 Fed. Reg. at 61,788–89.

These characteristics include adaptability, resiliency,

territoriality, an ability to reproduce quickly, and a tendency to

live in family packs of two to twelve, although sometimes

significantly larger. From 1995 to 2008, the Northern Rocky

Mountain gray wolf population grew an average of 20%

annually despite an average human-caused mortality rate of

23%. By 2002, the recovery goal had been met for three

consecutive years. At the end of 2011, the Northern Rocky

Mountain graywolf population consisted of a minimum of 1,774

wolves and 109 breeding pairs, thus far exceeding the Service’s

recovery goals. Rule, 77 Fed. Reg. at 55,539. This population

represented a 400-mile “southern range extension of a vast

contiguous wolf population that number[ed] over 12,000 wolves

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in western Canada and about 65,000 wolves across all of Canada

and Alaska.” Id. at 55,547.

The Service’s proposal to delist the remaining Northern

Rocky Mountain gray wolves in Wyoming was based on

federal-state cooperative efforts to develop an adequate state

regulatory framework, taking into account court decisions that

had found prior state plans deficient. First, because a significant

part of the Wyoming gray wolf subpopulation lives beyond

Wyoming’s jurisdiction on tribal and federal lands — the Wind

River Indian Reservation and Yellowstone National Park — the

Service concluded that it would suffice for Wyoming to

maintain a wolf population of “at least” 10 breeding pairs and

100 wolves in the parts of the State over which Wyoming has

jurisdiction. NPRM, 76 Fed. Reg. at 61,788. The wolves on

tribal and federal lands, in turn, would provide an “additional

buffer” above minimum recovery goals, id., thus roughly

aligning Wyoming with the existing management requirements

of 15/150 in Montana and Idaho, id. at 61,791. To meet these

obligations, Wyoming agreed to repeal a regulatory requirement

that it aggressivelymanage the wolf population down to the bare

minimum required by law. In addition, it stated in its

management plan that it intended “to maintain an adequate

buffer above the minimum recovery goals” to ensure that

unexpected mortality did not jeopardize its compliance with the

10/100 minima. Id. at 61,788. Next, Wyoming would manage

wolves as game animals in a permanent trophy area that

comprises 15.2% of the State, in which the vast majority of

Wyoming wolves live. During the peak dispersal season, the

trophy area would also expand southward approximately 1,300

square miles and cover an additional 1.3% of the State, to

protect wolves migrating to and from the Idaho subpopulation. 

The remaining area, which covers only 19% of the State’s

suitable wolf habitat, would be designated a predator area in

which wolves could be killed with few restrictions. 

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Taking these commitments together, the Service concluded

that Wyoming had provided for adequate regulatory

mechanisms and proposed delisting contingent upon Wyoming

enacting the agreed-upon changes into law. Id. at 61,811. 

Wyoming did so. See, e.g., Wyo. Stat. Ann. § 23-1-

101(a)(xii)(B)(I), (II); id. § 23-1-304(a), (n). Consistent with the

Service’s practice of submitting its rulemakings for independent

peer review, four of five peer reviewers agreed that, under the

proposed regulatory framework, Wyoming’s wolf population

would continue to be viable after delisting. Rule, 77 Fed. Reg.

at 55,538. Some commenters disputed the adequacy of

Wyoming’s management plan and, in particular, the danger that

human-caused mortalitycould reduce the wolf population below

Wyoming’s required minimum. See id. at 55,555. In response,

Wyoming submitted an Addendum to its management plan to

affirm its commitment to maintain an adequate population

buffer above minimum recovery levels, to “be determined

through an adaptive management approach and [which] may

fluctuate based on natural population dynamics and the effects

of specific management actions.” Wyo. Game & Fish Comm’n,

Addendum: Wyoming Gray Wolf Management Plan at 3–5

(Mar. 22, 2012) (the “Addendum”). The Service relied on this

Addendum in promulgating the Rule, stating, for instance, that

“Wyoming’s wolf population will be further buffered because

[the State Commission] intends to maintain an adequate buffer

above minimum population objectives.” 77 Fed. Reg. at 55,538;

id. at 55,555–56.

The district court, in response to two lawsuits challenging

the Rule, granted the environmental groups’ motion for

summary judgment in part. It upheld Wyoming’s management

plan as adequate to ensure genetic connectivity between the

three gray wolf subpopulations. It also upheld the Service’s

determination that the predator area in southern and eastern

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Wyoming does not constitute a “significant portion” of the gray

wolf’s range, and that a lack of protection in those areas will not

prevent genetic exchange. It concluded, however, that

Wyoming’s inadequate regulatoryframework rendered arbitrary

the Service’s determination that the wolf is not threatened or

endangered in Wyoming. The district court found that, although

the Rule imposed on Wyoming a duty to manage above the

minimum level of 10 breeding pairs and 100 wolves, and

although Wyoming statutes had been amended to require “at

least” the minimums, only the Addendum to the State’s

management plan included a commitment to managing above

that level and it was not legally enforceable. Absent that legal

commitment to maintain the buffer, the district court vacated the

Rule. See Defs. of Wildlife v. Jewell, 68 F. Supp. 3d 193,

209–10 (D.D.C. 2014).

The Secretary, Wyoming, Safari Club, and the National

Rifle Association appeal the vacatur of the Rule, and the

environmental groups (hereinafter, “appellees”) cross-appeal the

denial of summary judgment on their genetic connectivity and

“significant portion” challenges to the Rule. Our review of the

grant or denial of summary judgment is de novo. See Defs. of

Wildlife v. Jewell, 815 F.3d. 1, 7 (D.C. Cir. 2016). Where, as

here, the district court reviewed agency action under the

Administrative Procedure Act (“APA”), our review is highly

deferential to the agency, see American Wildlands v.

Kempthorne, 530 F.3d 991, 997–98 (D.C. Cir. 2008), while

according no particular deference to the judgment of the district

court, see In re Polar Bear Endangered Species Act Listing, 709

F.3d 1, 8 (D.C. Cir. 2013); accord Friends of Blackwater v.

Salazar, 691 F.3d 428, 432 (D.C. Cir. 2012). 

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II. 

Under Section 4(a) of the ESA, one of the statutory factors

that the Secretarymust consider in determining whether to delist

a protected species is “the inadequacy of existing regulatory

mechanisms.” 16 U.S.C. § 1533(a)(1)(D). Section 4(b), in turn,

requires the Secretary to consider a broad range of conservation

efforts, if any, being made by the state to protect the species. 

See id. § 1533(b)(1)(A). The Secretary contends that nothing in

the ESA requires those efforts to be legally binding. 

Tracking the familiar two-step analysis under Chevron

U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467

U.S. 837, 842–43 (1984), the Secretary points out that the plain

language of “regulatory mechanisms” is broader than only

legally binding measures. Had Congress intended to so limit the

analysis, it could have used “State law or regulation,” as it did

elsewhere in the ESA, e.g., 16 U.S.C. § 1535(f). Moreover, a

requirement that Section 4(b) efforts be legally binding would

be duplicative of Section 4(a)(1)(D), which addresses existing

“regulatory mechanisms.” Id. § 1533(a)(1)(D). Therefore, the

Secretary concluded the term “regulatory mechanisms” was

ambiguous and maypermissiblyinclude statemanagement plans

that do not have the force of law. We agree that Congress has

not “directly spoken” to the question, Chevron, 467 U.S. at 842,

and that the term is ambiguous,see id. at 843, for the reasons the

Secretaryexplains. Further, under Chevron’s second step, it was

“permissible,” id., for the Secretary to rely on Wyoming’s

management plan, which includes a commitment to manage for

a buffer in conjunction with its statutory obligations. The

Secretary properly does not view the management plan as

merely a speculative promise of future action in light of

Wyoming’s statutory and regulatory amendments. Although

appellees rely on the dictionary in maintaining that a

“‘regulation’ demands more than voluntary compliance,” see

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Appellees Br. 32 (citing 13 OXFORD ENGLISH DICTIONARY 524

(2d ed. 1989)), they overlook that Wyoming “is implicitly

‘required’ [to maintain a buffer] as the only practicable means

of achieving the explicit requirement of maintaining at least” 10

breeding pairs and 100 wolves on state land. Fed. Appellants

Reply Br. 13 (first emphasis added); Wyo. Stat. Ann. § 23-1-

304(a). 

Much of the parties’ underlying legal dispute about the

adequacy of Wyoming’s management plan has been addressed

by this court. In In re Polar Bear, 709 F.3d 1, this court

discussed “regulatory mechanisms” and “conservation efforts”

interchangeably, concluding that the Service reasonably found

that existing regulatory mechanisms were inadequate despite

Canada’s use of sport-hunting fees to fund local conservation

programs, which it determined did nothing to offset the threat to

polar bears from loss of sea ice habitat. Id. at 16–17. More

significantly, and post-dating the district court’s vacatur of the

Rule, this court upheld the Service’s determination to rely on a

state management plan in Defenders of Wildlife, 815 F.3d at 6,

17, crucial terms of which were conservation agreements

voluntarily entered into by landowners seeking to earn

environmental mitigation credits that would relieve them of

additional duties if the species at issue were listed. As here, the

exercise of judgment by the Service in that case was based upon

its experience under similar management plans in two adjacent

states, with species-protective terms that, although not

themselves legally codified, the Service had seen in operation

and was reasonably certain would be fulfilled. Id. at 6–7. There

too, environmental objections were raised similar to those of

appellees, but the court concluded the Service adequately

responded to them and exercised its judgment in a responsible

and reasoned way. Id. at 17. 

In other words, the question now before the court turns on

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whether the rulemaking record demonstrates the Service

exercised its judgment in a reasonable way in concluding that

Wyoming’s management plan, which explains how the State

intends to carry out its day-to-day implementation of its legal

obligations, will adequately protect Wyoming’s gray wolf

population after delisting. See 16 U.S.C. § 1533(a)(1)(D),

(b)(1)(A). That determination, this court acknowledged, is a

quintessential judgment call that Congress left to the Secretary,

and by delegation to the Service, which has years of experience

in evaluating what is reasonably likely to be implemented and

effective. See Defs. of Wildlife, 815 F.3d at 17. The ESA

provides no definition of “regulatory mechanisms,” and neither

the district court nor appellees suggests why the Secretary’s

interpretation is unreasonable. Although appellees maydisagree

with the Service’s conclusion that Wyoming can be trusted to

manage for a buffer, that is a separate question. Given

Congress’s direction that state conservation efforts must be

considered, 16 U.S.C. § 1533(b)(1)(A), their consideration as

part of the State’s “regulatory mechanisms” is hardly contrary

to congressional intent. Appellees disagree with the Service’s

assessment of Wyoming’s management plan, but not with the

statutory obligation to take into account all state conservation

efforts, or with the proposition that, in some instances, nonbinding measures “if sufficiently certain and effective to

alleviate a threat [of endangerment] may render a [legally

binding] regulatorymechanism unnecessary . . . after delisting,”

Appellees Br. 37-38. The Rule may be set aside only if

“arbitrary, capricious, an abuse of discretion, or otherwise not in

accordance with law.” Am. Wildlands, 530 F.3d at 997 (quoting

5 U.S.C. § 706(2)); see Motor Vehicle Mfrs. Ass’n of U.S., Inc.

v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 42–43 (1983). 

The record demonstrates that the Service reasonably and

adequately responded to concerns about the reliability of

Wyoming’s management plan. As the preamble to the Rule

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makes clear, the Service determined that Wyoming’s

management plan is a reliable indicator of how the State plans

to implement its statutes and regulations because that plan

aligned with the State’s own incentives. That is, managing at

minimum levels “would severely limit State flexibility to

address wolf depredation issues, limit wolf harvest

opportunities, and increase the risk of relisting.” Rule, 77 Fed

Reg. at 55,567. The Service similarly noted that a failure to

ensure a buffer would place Wyoming at risk of violating its

own statutory and regulatory commitments, if faced with

unexpected and uncontrollable sources of mortality like disease. 

Id. As a point of comparison, the Service also looked to the

post-delisting behavior of the adjacent states of Montana and

Idaho, which had both maintained wolf populations well above

minimum targets. See id. at 55,567–68. It noted that none of

the states had indicated any interest in managing down to

minimum levels; the Service underscored that state wildlife

managers “have consistently reiterated . . . their desire not to

come close to their floor levels” due to concerns about reduced

management flexibility and potential relisting. Id. at 55,567.

The district court did not question those assumptions or

considerations, but vacated the Rule solely because the

provision in Wyoming’s management plan for an additional

buffer is not legally binding. Nothing in the ESA demands that

level of certainty, however, and in Defenders of Wildlife, the

court upheld the withdrawal of a listing proposal where the

Service had found that the voluntary conservation efforts were

“sufficiently certain to be implemented” based on the strength

of the participating state’s incentives, 815 F.3d at 6 (quoting the

Service’s Policy for Evaluation of Conservation Efforts When

Making Listing Decisions, 68 Fed. Reg. 15,100, 15,114–15

(Mar. 28, 2003)). The Service’s decision to delist in the absence

of legal certainty is compatible with the ESA’s requirement for

monitoring of the species after delisting “for at least five years”

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and its emergency provisions authorizing the Secretary to take

immediate action to ensure the delisted species does not become

threatened or endangered again. See 16 U.S.C. § 1533(b)(7),

(g). So understood, the Service could reasonably conclude that

Wyoming’s efforts set forth in its management plan were

sufficiently certain to be implemented based on the strength of

the State’s incentives. And although Wyoming’s antagonistic

history toward wolves may provide appellees reason to disagree,

the Service took that history into account, see, e.g., Rule, 77

Fed. Reg. at 55,566, and it worked with the State to rectify

deficiencies previouslyidentified bythe courts, id. at 55,551–52. 

That appellees disagree with the Service does not undercut its

reasoned determination that, in light of Wyoming’s plan to

manage for a buffer, especially given the State’s own interests,

Wyoming has established an adequate regulatory framework.

Appellees nonetheless maintain the Service’s reliance on a

non-binding management plan is arbitrary because the Service

had already determined that the threat of human mortality must

be “adequately regulated.” Appellees Br. 38–39 (quoting Rule,

77 Fed. Reg. at 55,588). The preamble to the Rule does not state

that Wyoming’s buffer must be regulated; to the contrary, it was

the general threat of human-caused mortality that required

regulation “in the form of binding minimum population targets

by geographic area.” 77 Fed. Reg. at 55,568. The Service found

that such protections are in place. Wyoming is bound under its

own law to manage for “at least ten (10) breeding pairs of gray

wolves and a total of at least one hundred (100) individual gray

wolves.” Wyo. Stat. Ann. § 23-1-304(a). It will also use a

licensing system to regulate the frequency with which wolves

can be killed in the trophy area, see, e.g., Wyo. Admin. Code

Game Hunt Ch. 21 § 7, which affords Wyoming additional

control over human-caused mortality. See Greater Yellowstone

Coal., Inc. v. Servheen, 665 F.3d 1015, 1032 n.7 (9th Cir. 2011). 

Elsewhere, the preamble is even clearer on this point, discussing

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regulation and buffers separately: “[I]f human-caused mortality

is adequately regulated and population targets are sufficient to

allow for other potential unforeseen or uncontrollable sources of

mortality, no other potential threats are likely to compromise the

population’s viability.” Rule, 77 Fed. Reg. at 55,588. Because

the Service never deemed a regulatory buffer necessary, it did

not contradict itself by failing to require one. 

Nor did the Service disclaim any reliance on the states’

incentives to manage for a buffer, as appellees suggest. The

preamble to the Rule states: 

Should management needs be identified in future years,

all three States have regulatory authority to modify

management to meet such needs; although we did not

rely upon this in making our decision, we recognized

all three States have a strong incentive to maintain the

[Northern Rocky Mountain distinct population

segment] and its subpopulations well above minimum

population levels. 

77 Fed. Reg. at 55,590 (emphasis added). Appellees read “this”

to refer to the states’ “strong incentive” in the following clause,

while the Secretary responds that it refers to the states’

“regulatory authority” in the preceding clause. Even assuming

the sentence is not a model of clarity, its meaning is apparent

upon examination. If “this” were meant to refer to “strong

incentive” in the following clause, then there would be no

conceptual link between the two halves of the sentence, and they

would have been separated by a period rather than a semi-colon. 

The sentence, moreover, comes at the end of a section

explaining the adequacy of Wyoming’s current regulatory

structure, and cannot fairlybe understood as meaning “And even

if the current regulatory structure is inadequate, Wyoming can

just change it.” Instead, the Service noted Wyoming’s authority

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to legislate while making clear that it did not rely on this fact; it

relied on the State’s incentives to make sure future legislation is

unnecessary. The preamble, further, makes clear that the

Service did rely on state incentives, see, e.g., Rule, 77 Fed. Reg.

at 55,567, so it would have been illogical for it to claim

otherwise. 

Also without merit is Wyoming’s position that it is not

required to manage for a buffer at all. This sleight of hand may

lend some credence to appellees’ concerns about the State’s

commitment, but it cannot overcome the rulemaking record and

the documents submitted by the State in order to obtain

delisting. The Service considered “unacceptable” Wyoming’s

previous approach of managing down to bare minimum levels. 

Rule, 77 Fed. Reg. at 55,588. More to the point, the preamble

states that Wyoming “will, and must, maintain a buffer to

consistently meet its minimum management targets.” Id. at

55,556 (emphasis added). This language manifests a clear intent

by the Service to bind Wyoming, and therefore the preamble

itself has the force of law. See Kennecott Utah Copper Corp. v.

U.S. Dep’t of Interior, 88 F.3d 1191, 1223 (D.C. Cir. 1996).

Wyoming’s Addendum acknowledges that managing for

minimum populations would restrict its ability to deal with

depredating wolves and risk a status review and potential

relisting. See Rule, 77 Fed. Reg. at 55,567; 16 U.S.C.

§ 1533(b)(7), (g). As the Secretary explains, Wyoming is

implicitly required to maintain a buffer “as the only practicable

means of achieving the explicit requirement” of maintaining at

least 10 breeding pairs and 100 wolves on state land. Fed.

Appellants Reply Br. 13; Wyo. Stat. Ann. § 23-1-304(a). 

Appellees’ remaining challenges to Wyoming’s regulatory

framework, which the district court did not reach in light of its

vacatur of the Rule, also lack merit. First, the Service was not

arbitrary in relying on Wyoming’s management plan to maintain

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the statutorily required buffer, contrary to appellees’ contention

that maintaining a buffer would conflict with state law. 

Appellees point to Wyoming’s lethal take statute but ignore the

statutory and regulatory limitations that preserve the State’s

buffer authority. The statute provides for the promulgation of

rules under which permits “shall be issued as long as the

removals authorized by such permits could not reduce the

numbers of gray wolves below” the 10/100 minimum. Wyo.

Stat. Ann. § 23-1-304(n). The rules “shall provide for

suspending the issuance of permits or cancelling existing

permits if further lethal control could cause the numbers of gray

wolves to be reduced below” the minimum. Id. As

promulgated, those rules provide that a “Lethal Take Permit

shall only be issued by the Department if legal removal of gray

wolves will not prevent the Department from” meeting the

10/100 minimum. Wyo. Admin. Code Game Hunt Ch. 21 §

7(a). If further lethal take “may prevent the Department from

achieving [its] management objectives,” the issuance of

additional permits “shall be immediately suspended” and

existing permits “shall be immediately cancelled.” Id.

§ 7(b)(iii). In addition to these binding provisions, the

Addendum states that “[i]f the population approaches the

minimum recovery level . . . the Department has the statutory

authority to suspend issuance of Lethal Take Permits or cancel

existing Lethal Take Permits.” Addendum at 7.

The Service concluded that these provisions will not

interfere with Wyoming’s ability to maintain a buffer because

they require the suspension or cancellation of permits if further

mortality “could” compromise the State’s minimums. Rule, 77

Fed. Reg. at 55,557. If State law had said “would” or “will,”

then it might conflict with a buffer, but State law requires

suspension of permits upon the possibility of compromise. See

id. Appellees focus on the phrase “permits shall be issued,”

maintaining this mandatory language trumps any discretion the

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State might otherwise have to provide for a buffer. They ignore

that the mandate (“shall”) is tempered by a condition (“as long

as [issuance] could not reduce” the population below 10/100). 

Wyo. Stat. Ann. § 23-1-304(n) (emphasis added). In other

words, the mere possibility that minimums “could” be

compromised is enough to warrant the permit’s rejection. See

77 Fed. Reg. at 55,557. To the extent appellees also maintain

that, because the preamble’s reference to “could” is not present

in the State regulation, a permit must be issued as long as it “will

not prevent” Wyoming from reaching its minimum, Appellees

Br. 47–48 (quoting Wyo. Admin. Code Game Hunt Ch. 21

§ 7(a)), they overlook that the permit “shall only be issued . . .

if [it] will not prevent” Wyoming from reaching its minimum. 

Wyo. Admin. Code Game Hunt Ch. 21 § 7(a). The regulation

sets a necessary condition, not a mandate, for the permit to be

issued. See also id. § 7(b) (“If the requirements of . . . Section

7(a) are met . . . .”). As noted, a separate provision requires the

suspension or cancellation of permits if they “may” prevent

Wyoming from managing for 10/100, see id. § 7(b)(iii), thus

preserving the State’s ability to maintain a buffer if the wolf

population falls to near minimum levels.

 

Appellees also point out that Wyoming’s lethal take statute

authorizes a permit when wolves are “harassing . . . livestock or

other domesticated animals,” Wyo. Stat. Ann. § 23-1-304(n),

and yet it fails to define “harassing.” They worry that if the

State were to define “harassing” broadly, permitting under that

provision could jeopardize any planned buffer. In downplaying

this concern, the Service relied on a letter from Wyoming’s

Governor stating that prior to issuing a permit due to

harassment, State officials will verify that wolves were present

and that an actual attack was likely. Rule, 77 Fed. Reg. at

55,585–86 (citing Letter of Gov. Matthew H. Mead to U.S. Fish

& Wildlife Serv. (May 15, 2012)). Appellees maintain that the

Service’s reliance on the Governor’s letter was unreasonable,

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because it is a non-binding promise, but that issue is largely

irrelevant. Regardless of how broadly Wyoming defines

“harassing,” or whether it independently verifies harassment

before issuing a permit, it is legally bound to suspend all

harassment permits if they “could” compromise the State’s

minimums. Wyo. Stat. Ann. § 23-1-304(n). 

Second, appellees maintain the Service’s delisting action

was arbitrary because it failed to secure a regulatory

commitment to suspend permits where necessary to ensure

genetic connectivity between subpopulations. They correctly

point out that the Service had identified this as a “Major Issue”

in a mark-up of Wyoming’s proposed regulations,

recommending that Wyoming add genetic connectivity as

another grounds for suspending permits. Appellees, however,

tell only half of the story. The Service also noted in the mark-up

that it “could live with a commitment to this goal generally here,

and let the [management] plan include more specifics.” Draft

Revisions, Chapter 21 Regulations – Gray Wolf Management,

at 4 (Feb. 24, 2012). Consistent with that guidance, the final

State regulation added a general commitment to “ensur[ing]

genetic diversity and connectivity,” even though it was not

included in Section 4(a)(i) as the Service’s reviewer would have

preferred. See Wyo. Admin. Code Game Hunt Ch. 21 § 4(a)(ii). 

To the extent appellees maintain the Service arbitrarily

ignored that Wyoming’s lethal take regulations could override

that non-binding commitment to genetic connectivity, the

Service correctly points out that the ESA “does not mandate that

regulatory mechanisms exist to protect a species from any

conceivable impact.” Fed. Appellants ReplyBr. 31. Rather, the

ESA requires protection only “against threats that would cause

the species to be ‘an endangered species or a threatened

species.’” Id. (quoting 16 U.S.C. § 1533(a)(1)). Because the

rulemaking record showed that the wolves’ genetic health is

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strong, and because Wyoming has other tools at its disposal

(including reduction in harvest levels and in its own wolf control

actions, and, if necessary, translocating wolves to other

subpopulations), the Service concluded that the State’s

commitment to ensuring genetic connectivity into the Greater

Yellowstone Area (“GYA”) was sufficient. Rule, 77 Fed. Reg

at 55,595–96. Even if a close issue, because the Service

considered this permitting exception important,the studies in the

record support the Service’s view that genetic connectivity is not

an immediately pressing concern. See Michael D. Jimenez et

al., Wolf Dispersal in the Northern Rocky Mountains in Western

United States: 1993 – 2008 (2011) (“Jimenez Study”); Bridgett

M. vonHoldt et al., A Novel Assessment of Population Structure

and Gene Flow in Grey Wolf Populations of the Northern Rocky

Mountains of the United States, 19 Molecular Ecology 2214

(2010) (“vonHoldt Study”). The Service determined that “even

if no new genes entered into the GYA (a near impossibility),

genetic diversity is likely many decades, and perhaps a century

or more, away from becoming an issue and even then, it would

be unlikely to threaten the GYA population.” Rule, 77 Fed.

Reg. at 55,596. In this context, the Service’s acceptance of a

non-binding commitment to genetic connectivity was not

arbitrary and capricious. 

Third, appellees maintain that any buffer will be

undermined by Wyoming’s allowance for unlimited killing of

wolves “doing damage to private property.” Wyo. Stat. Ann.

§ 23-3-115. Although the Service relied on the State’s ability to

limit human-caused mortality, e.g., Rule, 77 Fed. Reg. at 55,555,

appellees view this provision to create a “hole . . . in the State’s

authority.” Appellees Br. 54. In particular, appellees are

concerned about the ability of ranchers to bait wolves onto their

property by leaving animal carcasses out. The Service

concluded this concern was “improbable [and] theoretical,”

noting that a representative of the Wyoming Attorney General’s

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office advised that baiting could be prosecuted under Wyoming

law. Rule, 77 Fed. Reg. at 55,561. In the Service’s judgment,

“such a scenario is unlikely to occur and exceedingly unlikely

to become a meaningful source of mortality” because ranchers

are more likely to seek a lethal take permit or hunting tag than

risk prosecution for baiting. Id. It noted as well that, baiting

aside, similar defense-of-propertyallowances have been in place

in Montana and Idaho since delisting and the overall wolf

population has continued to grow. Id. at 55,585. Indeed, the

record reflects that in Idaho only six defense-of-property kills

are known to have occurred in 2009 and thirteen in 2010. Thus,

the Service determined that the allowance “will not compromise

. . . Wyoming’s ability to meet the agreed-upon population

objectives.” Id. Appellees speculate that baiting could become

most problematic as population levels decrease to near 10/100,

at which point permits would be suspended and ranchers would

have no choice but to bait. Again, as the Secretary observes, the

ESA does not require a regulation to address every “far-fetched

‘what-if’ scenario” that opponents of delisting can imagine. 

Fed. Appellants Reply Br. 35. Given the slight impact of these

allowances in Idaho and Montana, and the absence of evidence

of baiting, the Service was not unreasonable in rejecting this

concern.

III.

On cross appeal, appellees contend that the Service

arbitrarily concluded that genetic connectivity is currently

sufficient, and will remain so after delisting. They also contend

the Service arbitrarily concluded Wyoming’s unregulated

predator area is not a “significant portion” of the wolves’ range. 

We are not persuaded that the district court erred in rejecting

appellees’ challenges.

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A.

To ensure the wolves’ long-term genetic health, the Service

has determined that, as a general rule, there should be at least

one effective migrant per generation, i.e., one wolf that travels

every four years from another subpopulation and passes on its

genes. Rule, 77 Fed. Reg. at 55,593. The GYA is the most

isolated core recoveryarea within the Northern RockyMountain

region, and thus a key concern of the Service has been the

number of effective migrants entering the GYA from northwest

Montana and central Idaho. 

The Service relied on two studies to determine that genetic

connectivity is currently sufficient. The Jimenez Study found

that five radio-collared wolves had migrated into the GYA

between 1992 and 2008, of which two were confirmed to have

mated successfully and one was confirmed not to have. Rule, 77

Fed. Reg. at 55,593. Because only 20–30% of wolves were

radio-collared, the Service determined that the number of actual

migrants was likely several times higher than the five

documented. Applying the Jimenez Study’s estimate that 35%

of migrants effectively breed, the Service concluded that there

was likely more than one effective migrant per generation, and

specifically as many as 1.5. Because the number of dispersals

increase as the wolf population increases, and the Northern

Rocky Mountain population increased from 55 to more than

1,655 over the course of the study, the Service inferred that a

large proportion of dispersals occurred in recent years. 

The vonHoldt Study sampled genetic material of Northern

Rocky Mountain wolves between 1995 and 2004, when the total

population was between 101 and 846 wolves. Id. It “detected

genetically effective dispersal among the three recovery areas,”

with high levels of genetic variation and low levels of

inbreeding. vonHoldt Study at 4412. As the population

expanded over the course of the study, “observed heterozygosity

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remained high,” id. at 4416, and “[i]nbreeding coefficients . . .

remained low for all recovery phases,” id. at 4417. A co-author

of the vonHoldt Study, Daniel Stahler, determined separately

that the genetic sampling data indicated a minimum of 0.42

effective migrants per generation had entered the GYA during

the study. There was consensus that this significantly

underestimated the number of actual effective migrants because

only about 30% of the population was sampled, but

disagreement about how to calculate the actual number. One

paper suggested that the Stahler estimate is “almost certainly

low by at least half,” Rule, 77 Fed. Reg. at 55,593 (quoting

Mark Hebblewhite et al., Restoration of Genetic Connectivity

Among Northern Rockies Wolf Populations, 19 Molecular

Ecology 4383, 4384 (2010) (“Hebblewhite et al., Genetic

Connectivity”)), but Stahler has objected to that particular

extrapolation as mere guesswork. The Rule’s preamble quoted

Hebblewhite’s multiplier as a “suggest[ion],” while noting that

additional analysis “may be needed” to pin down the actual

number. Id.

Appellees contend that these studies show that the

minimum requirement of one effective migrant per generation

has not been met, and that the Service’s contrary conclusion was

arbitrary. They claim the Jimenez Study found “[o]nly two

dispersing wolves actually bred,” Appellees Br. 61, thus

resulting in approximately 0.62 effective migrants per

generation. Leaving aside that this Study accounted for only

20–30% of the wolf population, appellees ignore that two other

dispersing wolves may have effectively bred, as only one of the

five was confirmed not to have done so. Thus, it is possible that

the dispersals observed by the Jimenez Study alone met the

threshold, even before extrapolating the effective dispersals of

the entire population. Appellees similarly take issue with the

Service’s reliance on the vonHoldt Study because even

assuming Hebblewhite is correct that the 0.42 effective migrant

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rate is too low by half, a 0.84 rate would still be insufficient. 

They understand Stahler to believe that Hebblewhite

overestimated the actual effective migrant rate. In fact, Stahler

clarified that he was not claiming that the actual number could

not be “as high as this (or higher in recent years),” but simply

that no data supported quantifying the actual number as at least

double the observed number. Email from Dan Stahler to Mike

Jimenez and Seth Willey (Sept. 7, 2011). Contrary to appellees’

assertion, the Service did not “fail[] to grapple with Stahler’s

objection,” Appellees Reply Br. 10, but rather cited Stahler in

noting that additional analysis may be needed. Rule, 77 Fed.

Reg. at 55,593.

The ESA requires that the Service rely on the “best

scientific . . . data available,” 16 U.S.C. § 1533(b)(1)(A), and the

Service’s evaluation of this data falls within its area of expertise

and is entitled to deference by the court. Defs. of Wildlife, 815

F.3d at 14. Appellees do not suggest that there are better studies

available, nor do they meaningfully dispute that both studies’

results are understated, requiring some extrapolation upward. 

Instead, they disagree with the Service’s conclusion that the

studies show an effective migrant rate above one per generation. 

Such competing views about scientific data and policy choices,

however, fail to show that the Service’s conclusions were

arbitrary and capricious or contrary to law. In re Polar Bear,

709 F.3d at 3.

Of course, whether these levels of genetic connectivity will

be sustained after delisting may be a closer question, but such a

projection is still within the expertise of the Service. Two

Service scientists noted that, because effective dispersals are

hovering just above one-per-generation, “there is not a lot of

wiggle room per assuring effective migration through natural

dispersal into the GYA.” Ed Bangs and Mike Jimenez, Draft

Memo at 3 (May 24, 2011) (“Bangs Memo”). The Service

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nonetheless concluded that “the GYA wolf population will not

be threatened by lower genetic diversity in the foreseeable

future.” Rule, 77 Fed. Reg. at 55,596. It projected that the

overall Northern Rocky Mountain wolf population will stabilize

around 1,000 wolves after delisting in Wyoming. Id. at 55,594. 

Although appellees object that the projection has no basis,

especially in light of the states’ documented hostility toward

wolves and their binding commitments only to manage 400

total, in reality, two years after delisting, known 2011

populations remained many times larger than the minimums in

Idaho (746), Montana (653), and the Northern RockyMountains

as a whole (1,774). Rule, 77 Fed. Reg. at 55,539. These

population numbers in adjacent states, which offer an indication

of what Wyoming will experience after delisting, provided a

rational basis for the Service to project that the Northern Rocky

Mountain population will level off around 1,000 wolves.

Appellees still maintain that even if the Service’s projection

is accepted, it was arbitrary to conclude that effective dispersals

will reach one per generation because of the increase in wolf

killings and the paucity of effective dispersals when the

population was under 1,000. As noted, currently known levels

of effective dispersal provide very little cushion above the oneper-generation threshold, so “very small changes in survival of

a very small proportion of dispersing wolves into Wyoming may

have significant repercussions.” Bangs Memo at 2. The

Secretary explains that the 1,300 square-mile flex area, which

sits across the border from two protected areas in Idaho, was

created to provide a protected corridor for dispersing wolves as

they seek a southern route around the Teton Mountains. The

Secretary also discounts the importance of the expansive

predator area, because it contains little suitable habitat and sits

to the southeast of the GYA subpopulation, while the Montana

and Idaho subpopulations are to the northwest. And the

Secretary allows for the possibility that some dispersing wolves

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will wander into the predator area en route to the GYA, but

concludes “it is certainly not the only or even the likeliest

route.” Fed. Appellants Reply Br. 52; see 77 Fed. Reg. at

55,564. 

Appellees object that the seasonal flex area is too small to

protect migrants, citing a recommendation by Bangs and

Jimenez that the permanent trophy area extend south to Big

Piney, WY. As to length, the flex area is only protected for 4.5

months per year, while an average dispersal takes 5.5 months to

complete, thus ensuring that “the average dispersing wolf [will

pass through] a free-fire zone for at least part of its journey.” 

Appellees Br. 70–71. And even in the protected flex area,

appellees point out, dispersing wolves can still be killed bythose

holding lethal take or hunting permits. Appellees also refer to

the Service’s conclusion in 2009 that, due to snow depths and

concentration of prey, wolves dispersing into the GYA from the

west were likely to skirt the mountains and “move through the

predatory area.” See Final Rule to Identify the Northern Rocky

Mountain Population of Gray Wolf as a Distinct Population

Segment and To Revise the List of Endangered and Threatened

Wildlife, 74 Fed. Reg. 15,123, 15,176 (Apr. 2, 2009) (“2009

Rule”). 

This aspect of appellees’ challenge too involves some

sleight of hand. The predatory area proposed in 2009 was much

larger (at least 88% of the State) than the current proposal. See

id. The Service had recommended that Wyoming “minimize

take in all suitable habitat and across all of Wyoming’s potential

migration routes,” id., which the current permanent and flex

trophy areas are aimed to accomplish. Rule, 77 Fed. Reg. at

55,564. Moreover, the Service does not dispute that migrants

will enter the predator area, but explains why that would not

preclude dispersals: migrants are harder to locate and kill than

resident wolves, as demonstrated by Idaho hunting data showing

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minimal harvest in areas with few resident wolves even during

peak dispersal season. See id.

Were genetic connectivity entirely dependent on natural

dispersals, it is possible Wyoming’s current management plan

would prove inadequate due to the apparent closeness to the

minimum threshold in the GYA. But the Service persuasively

responded, pointing out that Wyoming has committed to account

for dispersing wolves when setting quotas, and to collect

samples to monitor for genetic diversity; further, if monitoring

shows that natural dispersals are inadequate, it will modify its

population management program; and if those modifications

prove inadequate over numerous generations, it will employ

human-assisted genetic exchange as a stopgap measure. Rule,

77 Fed. Reg. at 55,595–96. In this way the Rule accounts for,

and protects against, the possibility that natural dispersals could

fall short, or at least it was not arbitrary and capricious for the

Service to so conclude. 

Appellees lastly contend that the ESA’s purpose precludes

the Service from delisting a species where its survival depends

on human-assisted translocation (essentially, trapping a wolf and

trucking it to another subpopulation to breed). This proves too

much. The ESA aims “to provide a program for the

conservation of” endangered and threatened species, 16 U.S.C.

§ 1531(b), by using “all methods and procedures which are

necessary” to bring those species back to the point where the

law’s protections are no longer necessary, id. § 1532(3). From

this purpose, appellees infer a prohibition against delisting if the

ESA’s “methods and procedures” — i.e., “live trapping[] and

transplantation,” id. — are still necessary. Yet if the Service

cannot delist a species when live trapping and transplantation

may still be necessary, the logic of appellees’ interpretation

would mean delisting could not occur if other less invasive

methods like “research, census, law enforcement, [and] habitat

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acquisition” are still necessary. See id. By the same token, the

Secretary’s regulations contemplate delisting even if the species

depends on continued regulatory protection, see 50 C.F.R.

§ 424.11(d), so appellees’ view of the statutory imperative as

allowing only an entirely self-sufficient species to be delisted

can hardly be correct. The authority cited by appellees, Trout

Unlimited v. Lohn, 559 F.3d 946 (9th Cir. 2009), is not to the

contrary. There, the Ninth Circuit concluded that the ESA

requires consideration of the entire species, not just the naturally

hatched portion, and that, in deciding to downlist the species, the

Service rationally considered how the artificially hatched fish

benefit naturally hatched fish. See id. at 957–58. Thus,

downlisting was appropriate even though that decision rested on

the use of “artificial propagation,” one of the ESA’s “methods

and procedures.” See 16 U.S.C. § 1532(3).

Notably, the Secretary emphasizes that under the Rule

translocation would only be necessary as a last resort, and that

“‘natural connectivity is the preferred approach.’” Fed.

Appellants Reply Br. 54 (quoting 77 Fed. Reg. at 55,565). The

Service expects natural levels of dispersal to be sufficient, so

“wolves in the GYA are not expected to need or rely on humanassisted migration often, if ever.” Rule, 77 Fed. Reg. at 55,565. 

This is not a case, then, in which greater reliance on such

techniques could render a delisting decision arbitrary. It suffices

to conclude that the ESA did not prohibit the Service from

delisting in Wyoming where translocation could eventually be

necessary as a stopgap measure after many generations of

insufficient natural connectivity.

B.

Section 3 of the ESA defines an endangered species as one

in danger of extinction “throughout all or a significant portion

of its range.” 16 U.S.C. § 1532(6). In Wyoming’s predator area

wolves can be killed without restriction, and appellees contend

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it was arbitrary for the Service to conclude this is not a

significant portion of the wolves’ range. 

The predator area contains only 19% of the State’s suitable

habitat, and as of 2011, it contained only 3 of 27 breeding pairs,

8 of 48 packs, and 46 of 328 wolves in Wyoming. Rule, 77 Fed.

Reg. at 55,602. The Service concluded that even if all of those

wolves were killed, the remaining wolves in Wyoming would be

sufficient to maintain a recovered population. Id. As for

dispersing wolves, it acknowledged that some will be killed in

the predator area, but it concluded that even if no dispersing

wolves successfully traversed the Wyoming predator area,

genetic health would not be affected to the point of endangering

the remainder, id. at 55,602–03, due in part to “the current high

level of genetic diversity” in the Northern Rocky Mountain gray

wolf population, id. at 55,596. Thus, according to the Service,

the predator zone cannot be deemed a “significant portion” of

the wolves’ range because the species would not become

endangered even if every single wolf there were killed. Id. at

55,602–03. 

Appellees respond that the Service “cannot have it both

ways, deeming the predator zone insignificant even if all wolves

in the area are killed, but then discounting the genetic-exchange

impacts . . . by speculating that some wolves may survive” their

passage through the predator zone. Appellees ReplyBr. 28. But

the Service has not offered “contradictory statements,” see id.,

only complementary ones: it expects that some wolves will

successfully traverse the predator area, but even if that proves

incorrect, genetic health will not decline so much as to endanger

the wolves. Rule, 77 Fed. Reg. at 55,602–03. Appellees’

challenge rests on the mistaken assumption that migrants have

no choice but to traverse the predatory area, making “safe

passage through this area . . . essential to genetic exchange.” 

Appellees Br. 78. The rulemaking record is clear, however, that

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wolves can disperse directly into the GYA from Idaho and

Montana “without moving through Wyoming” at all, thereby

accomplishing the desired connectivity goal. Rule, 77 Fed. Reg.

at 55,564; see also id. at 55,534, 55,540. 

Appellees also maintain that the Service irrationally

reversed its 2009 determination that all of Wyoming constituted

a significant portion of the wolves’ range. See 2009 Rule, 74

Fed. Reg. at 15,183. This 2009 determination was deemed

arbitrary and capricious in 2010, see Wyoming v. U.S. Dep’t of

the Interior, Nos. 09-CV-118J & 09-CV-138J, 2010 WL

4814950, at *45 (D. Wyo. Nov. 18, 2010), when based on a

broader, more inclusive definition of “significant portion,”

pursuant to a 2007 opinion of the Solicitor of the Interior that

was later withdrawn. See Fed. Appellants Reply Br. 57. By

contrast, the 2012 Rule is based on the Service’s new, more

restrictive interpretation of the ambiguous phrase “significant

portion” as a portion of the range that would endanger the

species’ survival if removed. See Rule, 77 Fed. Reg. at

55,601–02. Appellees do not challenge the Service’s definition

of “significant portion;” rather, they maintain that even under

that definition the predator area is significant and that the

Service fails to explain the reversal of its 2009 determination. 

In 2010, the district court ruled that all of Wyoming was not

appropriately subjected to trophy game management, without

specifying how much of Wyoming could be so designated. In

appellees’ view, then, the factual underpinnings of the 2009

determination are unaffected by the district court’s ruling, and

yet the Service has failed to explain why they are no longer

controlling. 

The 2009 determination has been overtaken by events. Not

only has the Service adopted a new definition of “significant

portion of its range,” see Rule, 77 Fed. Reg. at 55,602–03, but

Wyoming’s regulatory framework has changed, id. at

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55,589–90, and new scientific data has become available in

recent studies, see id. at 55,593 (citing the vonHoldt Study and

the Jimenez Study). Indeed, Hebblewhite has concluded that

vonHoldt’s 2010 study is more comprehensive and robust than

her earlier work showing a lack of genetic connectivity:

“[C]oncerns that this highly vagile and fecund species might

suffer negative effects of genetic isolation . . . have been

effectively laid to rest by vonHoldt et al.’s (2010) exhaustive

work.” Hebblewhite et al., Genetic Connectivity at 4384. The

Service has offered ample rationale for determining that the

predator area was never “envisioned to meaningfully contribute

to wolf recovery in the region” and is thus not a “significant

portion of its range.” Rule, 77 Fed. Reg. at 55,602–03.

Accordingly, we reverse the judgment vacating the Rule

and otherwise affirm. The court has no occasion to consider the

additional contentions of the Safari Club and NRA that the Rule

reasonably advances conservation efforts and social tolerance

for wolves among hunters and ranchers.

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