Humane Society of the United States v. Ryan Zinke (Lead)

United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued October 18, 2016 Decided August 1, 2017

No. 15-5041

HUMANE SOCIETY OF THE UNITED STATES, ET AL.,

APPELLEES

v.

RYAN ZINKE, SECRETARY OF THE INTERIOR, ET AL.,

APPELLEES

U.S. SPORTSMEN’S ALLIANCE FOUNDATION, ET AL.,

APPELLANTS

STATE OF WISCONSIN, ET AL.,

APPELLEES

Consolidated with 15-5043, 15-5060, 15-5061

Appeals from the United States District Court

for the District of Columbia

(No. 1:13-cv-00186)

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

argued the cause for federal appellants Zinke, et al. With her

on the briefs were John C. Cruden, Assistant Attorney General

at the time the brief was filed, and David C. Shilton, Attorney.

2

Nathan Gambill, Assistant Attorney General, Office of the

Attorney General for the State of Michigan, argued the cause

for appellants State of Michigan, et al. With him on the briefs

were Bill Schuette, Attorney General, Aaron D. Lindstrom,

Solicitor General, and Pamela J. Stevenson, Assistant Attorney

General.

James H. Lister argued the cause for appellant-defendant-

intervenors Hunter Conservation Coalition, et al. With him on

the briefs were Anna M. Seidman, Douglas S. Burdin, John I.

Kittel, and Michael T. Jean. Jeremy E. Clare and William P.

Horn entered appearances.

Brad Schimel, Attorney General, Office of the Attorney

General of the State of Wisconsin, Ryan J. Walsh, Chief

Deputy Solicitor General, Daniel P. Lennington, Deputy

Solicitor General at the time the briefs were filed, Jennifer L.

Vandermeuse, Assistant Attorney General, and Thomas J.

Dawson, Assistant Attorney General at the time the brief was

filed, were on the brief for State of Wisconsin and Wisconsin

Department of Natural Resources.

Kathryn Landrum, Assistant Attorney General, Office of

the Attorney General for the State of Minnesota, was on the

brief for amicus curiae the State of Minnesota in support of

appellants.

Peter K. Michael, Attorney General, Office of the

Attorney General for the State of Wyoming, James Kaste and

D. David DeWald, Assistant Attorneys General, and Michael

J. McGrady, Assistant Attorney General at the time the brief

was filed, Joseph A. Foster, Attorney General, Office of the

Attorney General for the State of New Hampshire, Douglas A.

Bahr, Solicitor General, Office of the Attorney General for the

State of North Dakota at the time the brief was filed, Sean D.

3

Reyes, Attorney General, Office of the Attorney General for the

State of Utah, Cynthia Coffman, Attorney General, Office of

the Attorney General for the State of Colorado, Lawrence G.

Wasden, Attorney General, Office of the Attorney General for

the State of Idaho, Derek Schmidt, Attorney General, Office of

the Attorney General for the State of Kansas, and Timothy C.

Fox, Attorney General, Office of the Attorney General for the

State of Montana, were on the brief for amici curiae the States

of Wyoming, et al. in support of defendants-appellants and

intervenor-defendants-appellants.

Ralph E. Henry argued the cause for appellees The

Humane Society of the United States, et al. With him on the

brief was Elizabeth Runyan Geise.

Amy R. Atwood and Collette L. Adkins were on the brief

for amicus curiae Center for Biological Diversity in support of

plaintiffs-appellees The Humane Society of the United States.

Before: GRIFFITH, MILLETT, and PILLARD, Circuit Judges.

Opinion for the Court filed by Circuit Judge MILLETT.

MILLETT, Circuit Judge: The gray wolf once roamed in

large numbers across the contiguous forty-eight States. But by

the 1960s, hunting, depredation, and habitat loss drove the gray

wolf to the brink of extinction, and the federal government

declared the gray wolf an endangered species. After a portion

of the gray wolf population rebounded, the government

promulgated the rule at issue here, which removes from federal

protection a sub-population of gray wolves inhabiting all or

portions of nine states in the Western Great Lakes region of the

United States. The Humane Society of the United States

challenges that rule as a violation of the Endangered Species

Act of 1973 (“Act”), 16 U.S.C. § 1531 et seq., and the

4

Administrative Procedure Act (“APA”), 5 U.S.C. § 551 et seq.

Because the government failed to reasonably analyze or

consider two significant aspects of the rule—the impacts of

partial delisting and of historical range loss on the already-

listed species—we affirm the judgment of the district court

vacating the 2011 Rule.

I

A

Congress enacted the Endangered Species Act “to halt and

reverse the trend toward species extinction,” and to do so

“whatever the cost.” Tennessee Valley Auth. v. Hill, 437 U.S.

153, 184 (1978). As relevant here, a species is “endangered”

if it “is in danger of extinction throughout all or a significant

portion of its range[.]” 16 U.S.C. § 1532(6). A species is

“threatened” if it “is likely to become an endangered species

within the foreseeable future throughout all or a significant

portion of its range.” Id. § 1532(20).

The Endangered Species Act directs the Secretary of the

Interior to apply five factors in determining whether a

“species” is endangered or threatened: (i) “the present or

threatened destruction, modification, or curtailment of [the

species’] habitat or range”; (ii) “overutilization [of the species]

for commercial, recreational, scientific, or educational

purposes”; (iii) “disease or predation”; (iv) “the inadequacy of

existing regulatory mechanisms”; and (v) “other natural or

manmade factors affecting [the species’] continued

existence.” 16 U.S.C. § 1533(a)(1). In making that

determination, the Secretary must rely on “the best scientific

and commercial data available[.]” Id. § 1533(b)(1)(A). The

Secretary of the Interior has delegated the authority to

determine whether a species is “endangered” or “threatened”

5

to the Fish and Wildlife Service (“Service”). 50 C.F.R.

§ 402.01(b).

The “species” that the Endangered Species Act protects

are defined to include “any subspecies of fish or wildlife or

plants, and,” of most relevance here, “any distinct population

segment of any species of vertebrate fish or wildlife which

interbreeds when mature.” 16 U.S.C. § 1532(16). 1 The Act

does not define “distinct population segment.” Nor do agency

regulations. The Service, however, has issued policy guidance

stating that the existence of a “distinct population segment”

turns upon the discreteness and significance of a sub-

population as compared to the larger species population.

Policy Regarding the Recognition of Distinct Vertebrate

Population Segments Under the Endangered Species Act, 61

Fed. Reg. 4,722, 4,725 (Feb. 7, 1996) (“Segment Policy”). The

Segment Policy emphasizes that the Service’s authority to

recognize distinct population segments should be “exercised

sparingly.” Id. at 4,724.

To qualify as “discrete” under the Segment Policy, a

domestic animal population must be “markedly separated from

other populations of the same taxon as a consequence of

physical, physiological, ecological, or behavioral factors[.]”

Segment Policy, 61 Fed. Reg. at 4,725. The “significance” of

a potential segment turns on such factors as: (i) the

“[p]ersistence of the discrete population segment in an

ecological setting unusual or unique for the taxon”; (ii)

“[e]vidence that loss of the discrete population segment would

result in a significant gap in the range of a taxon”; (iii)

1

The Endangered Species Act defines “species” in a way that

differs from the scientific definition of species. As used in this

opinion, “species” refers to the Act’s definition. The phrase

“taxonomic species” or “taxon” refers to the scientific definition of

a species.

6

“[e]vidence that the discrete population segment represents the

only surviving natural occurrence of a taxon that may be more

abundant elsewhere as an introduced population outside its

historic range”; or (iv) “[e]vidence that the discrete population

segment differs markedly from other populations of the species

in its genetic characteristics.” Id.

Another key term in analyzing a species’ need for

protection—“range”—is also left undefined by the Act. In

2014, the Service adopted a policy statement defining “range”

as a species’ “‘current range,’ not [its] ‘historical range.’”

Final Policy on Interpretation of the Phrase “Significant

Portion of its Range” in the Endangered Species Act’s

Definitions of “Endangered Species” and “Threatened

Species,” 79 Fed. Reg. 37,578, 37,583 (July 1, 2014) (“Range

Policy”). The Range Policy further explains that a portion of a

species’ range will be considered “significant” if the species

would be in danger of extinction or likely to become so in the

foreseeable future without that portion of its range. Id. at

37,581.

Once the Service determines that a species is endangered

or threatened, it must add the species to a list of protected

species in the Federal Register. 16 U.S.C. § 1533(c)(1). A

listed species receives robust federal protections, including

prohibitions on possessing, killing, selling, importing, or

exporting its members. Id. § 1538(a). Any person that

knowingly violates those prohibitions faces criminal sanctions,

including fines of up to $50,000 or a year of imprisonment. Id.

§ 1540(b)(1).

The Act further requires the Service “from time to time

[to] revise” its lists of endangered and threatened species “to

reflect recent determinations, designations, and revisions.” 16

U.S.C. § 1533(c)(1). Every five years, the Service must

7

“review * * * and determine * * * whether any such species

should * * * (i) be removed from such list; (ii) be changed in

status from an endangered species to a threatened species; or

(iii) be changed in status from a threatened species to an

endangered species.” Id. § 1533(c)(2)(A), (B).

B

1

Regional subspecies of the taxonomic species “gray wolf”

(Canis lupis) were declared endangered by the federal

government between 1966 and 1976. The timber wolf (Canis

lupus lycaon) was first designated as endangered and afforded

protection in 1967, 32 Fed. Reg. 4,001, 4,001 (March 11,

1967), followed by the Northern Rocky Mountain wolf (Canis

lupus irremotus) in 1973, 38 Fed. Reg. 14,678, 14,678 (June 4,

1973). Both the Mexican wolf (Canis lupus baileyi) and the

Texas wolf (Canis lupus monstrabilis) were added to the list in

1976. 41 Fed. Reg. 17,736, 17,737 (April 28, 1976); 41 Fed.

Reg. 24,062, 24,066 (June 14, 1976).

With the wolves’ numbers rebounding in certain areas, the

federal government in 1978 reclassified the gray wolf from its

regional listings into a single species listing divided into two

groups: Minnesota gray wolves, which the Service determined

had recovered to the point of only being threatened, and the

gray wolf in the remaining forty-seven States, which remained

endangered. See Reclassification of the Gray Wolf in the

United States and Mexico, with Determination of Critical

Habitat in Michigan and Minnesota, 43 Fed. Reg. 9,607, 9,608,

9612 (March 9, 1978) (“1978 Rule”). 2

2

Those two groups were listed before the Endangered Species

Act was amended to add “distinct population segments” to the

8

In 2003, the Service subdivided the gray wolf listing into

three “distinct population segments”: an Eastern segment, a

Western segment, and a Southwestern segment. Final Rule to

Reclassify and Remove the Gray Wolf From the List of

Endangered and Threatened Wildlife in Portions of the

Conterminous United States; Establishment of Two Special

Regulations for Threatened Gray Wolves, 68 Fed. Reg. 15,804,

15,818 (April 1, 2003) (“2003 Rule”). Included in the Eastern

segment were the Minnesota gray wolf population and any gray

wolf population that existed in the Northeast region of the

United States. Id. at 15,859. The Service then designated the

wolves in the Eastern and Western segments as threatened

rather than endangered. Id. at 15,857–15,858, 15,862. The

wolves within the Southwestern segment continued to be listed

as endangered. Id.

Two district courts struck down the 2003 Rule’s attempted

designation of those three distinct population segments. First,

a district court in Oregon ruled that, by downlisting the species

based solely on the viability of a small population within that

segment, the Service was effectively ignoring the species’

status in its full range, as the Endangered Species Act requires.

See Defenders of Wildlife v. Secretary, U.S. Dep’t of the

Interior, 354 F. Supp. 2d 1156, 1168–1169 (D. Or. 2005). The

2003 Rule thus had the “effect of rendering the phrase

[significant portion of its range] superfluous.” Id. at 1168

definition of “species.” See Endangered Species Act Amendments

of 1978, Pub. L. No. 95-632, 92 Stat. 3,751, 3,752. Prior to the 1978

amendments, the Act defined “species” to “include[] any subspecies

of fish or wildlife or plants and any other group of fish or wildlife of

the same species or smaller taxa in common spatial arrangement that

interbreed when mature.” Endangered Species Act of 1973 § 3, Pub.

L. 93-205, 87 Stat. 884, 886.

9

(alteration in original; internal quotation marks and citation

omitted).

Second, a district court in Vermont concluded that the

Service impermissibly designated and downlisted the Eastern

segment of gray wolves. National Wildlife Fed’n v. Norton,

386 F. Supp. 2d 553, 564–565 (D. Vt. 2005). Fatal to the

Service’s determination, the court concluded, was the Service’s

decision to “lump” into the Eastern segment any gray wolves

in the Northeast region of the United States, without

ascertaining whether a gray wolf population even existed in the

Northeast. See id. In so holding, the court rejected the

Service’s argument that the Endangered Species Act required

it to include any Northeast region wolves in the segment to

avoid turning them into an impermissible “non-DPS remnant”

of gray wolves that neither fell within a recognized segment

nor had independent species or subspecies status of its own. Id.

at 564–565. In the district court’s view, the Service instead

could have continued the remnant’s endangered-species status.

See id. at 565.

2

The government did not appeal either the Oregon or the

Vermont decision. Instead, in what turned out to be the first

round in successive attempts to delist the gray wolves in the

Western Great Lakes area, the Service promulgated a new rule

in 2007 that created a “Western Great Lakes gray wolf distinct

population segment” and simultaneously delisted that segment,

removing it completely from the Endangered Species Act’s

protections. See Final Rule Designating the Western Great

Lakes Populations of Gray Wolves as a Distinct Population

Segment; Removing the Western Great Lakes Distinct

Population Segment of the Gray Wolf From the List of

Endangered and Threatened Wildlife, 72 Fed. Reg. 6,052,

10

6,052 (Feb. 8, 2007) (“2007 Rule”). That rule soon met the

same fate as its two predecessors. A district court in this circuit

vacated it for “fail[ing] to acknowledge and address crucial

statutory ambiguities” concerning the creation of distinct

population segments for the purpose of delisting. Humane

Society of the U.S. v. Kempthorne, 579 F. Supp. 2d 7, 9 (D.D.C.

2008); id. at 15. Again, the government did not appeal.

In December 2008, the Solicitor of the Department of the

Interior issued a memorandum analyzing the statutory

authority for designating distinct population segments for the

specific purpose of delisting them. See U.S. Fish and Wildlife

Service Authority under Section 4(c)(1) of the Endangered

Species Act to Revise Lists of Endangered Species and

Threatened Species to “Reflect Recent Determinations,” Office

of the Solicitor, U.S. Dep’t of Interior (Dec. 12, 2008)

(“Solicitor’s Opinion”). The Solicitor concluded that the Act

unambiguously allows the Service to identify a segment and

then delist it. Id. at 3–5.

The Solicitor started by noting that, once the Service lists

a species as threatened or endangered, it is obligated to

periodically revise its list of endangered or threatened species

in light of any changes in the conservation status of a species.

Solicitor’s Opinion 3 (citing 16 U.S.C. § 1533(a), (c)(1)). The

Solicitor then reasoned that the Endangered Species Act

imposes no textual limit on the Service’s authority to revise its

list of endangered or threatened species based on intervening

information and determinations. Id. at 4. On that basis, the

Solicitor determined that the Act unambiguously permits the

Service to designate a segment within a listed species,

determine that the segment is no longer endangered or

threatened, and delist it. Id. at 3–5.

11

The Solicitor further opined that, even were the statutory

text ambiguous, his interpretation was a reasonable

construction of the statute and its purposes. Solicitor’s Opinion

5–6. The Solicitor reasoned that, because subspecies and

segments are parts of taxonomic species, any listing of a

taxonomic species necessarily includes a listing of its

constituent segments or subspecies. Id. at 7. On that basis, the

Solicitor concluded that, even if the Service could only delist

an already-listed segment, that requirement would be satisfied

by the listing of the species that encompassed the segment. Id.

The Solicitor also reasoned that delisting a recovered segment

is consistent with the express statutory policies of the Act,

including fostering federal-state cooperation and focusing

resources where they are most needed. Id. at 13–19.

3

Based on the Solicitor’s Opinion, the Service in 2009

republished the 2007 rule without notice and comment, adding

a discussion of “Issues on Remand.” Final Rule To Identify

the Western Great Lakes Populations of Gray Wolves as a

Distinct Population Segment and to Revise the List of

Endangered and Threatened Wildlife, 74 Fed. Reg. 15,070,

15,075 (April 2, 2009) (“2009 Rule”). The Service relied on

the Solicitor’s determination that the Endangered Species Act

permits the Service to “remove an already-listed entity from the

appropriate list in its entirety, or to reduce the geographic or

taxonomic scope of a listing to exclude a group of organisms

previously included as part of an already-listed entity.” Id. at

15,083 (quoting Solicitor’s Opinion 5 n.8).

Round Two of the Service’s attempt to delist the gray

wolves in the Western Great Lakes area ended in the same

manner as Round One: the 2009 Rule was challenged and

vacated after the Service acknowledged that it had

12

impermissibly promulgated the rule without notice and

comment, and agreed to settle the case. Humane Society of the

U.S. v. Salazar, No. 09–1092, Docket Entry No. 27 (D.D.C.

July 2, 2009).

As a consequence of all those regulatory missteps, the

status of gray wolves remained in 2009 what it had been in

1978: Gray wolves in Minnesota were listed as “threatened,”

while the wolves in the forty-seven other contiguous States

were listed as “endangered.”

C

1

This case is Round Three in the Service’s effort to divide

and delist gray wolves in the broader Western Great Lakes

region. In 2011, the Service issued a final rule that, in reliance

on the Solicitor’s Opinion, purported to “revise the boundaries

of the Minnesota” gray wolf population to include the wolves

in all or portions of eight other states. Revising the Listing of

the Gray Wolf (Canis lupus) in the Western Great Lakes, 76

Fed. Reg. 81,666, 81,666, 81,670 (Dec. 28, 2011) (“2011

Rule”). Specifically, the 2011 Rule designated the gray wolf

population in Minnesota, Wisconsin, and Michigan, as well as

portions of North Dakota, South Dakota, Iowa, Illinois,

Indiana, and Ohio, as the Western Great Lakes Distinct

Population Segment. Id. at 81,666, 81,670. In its next breath,

the Service delisted that segment. Id. at 81,723.

In doing so, the Service again expressly adopted the legal

analysis in the Solicitor’s Opinion regarding its authority to

delist a segment. See 2011 Rule, 76 Fed. Reg. at 81,670,

81,683. The Service then reasoned that, because more than 400

miles existed between the gray wolf population in the Western

13

Great Lakes region and other gray wolf packs, the population

qualified as “discrete.” Id. at 81,671. The Service further

found that the loss of the Western Great Lakes population of

gray wolves, which contained “70 percent of North American

gray wolves known to occur south of Canada,” would

constitute a “significant gap in the range” of the “gray wolves

in the United States[.]” Id. at 81,672. The Service thus

concluded that the population qualified as “significant.” Id.

Accordingly, the Service determined that the Western Great

Lakes population of gray wolves constituted a “distinct

population segment.” Id.

The Service next considered whether the segment was

endangered or threatened throughout all or a significant portion

of its range. 2011 Rule, 76 Fed. Reg. at 81,721–81,723. In

making that determination, the Service explained that it would

interpret “range” to mean “current range.” Id. at 81,722. The

Service also clarified that it would consider a portion of a

species’ range to be “significant” if that portion is “important

to the conservation of the species because it contributes

meaningfully to the representation, resiliency, or redundancy

of the species.” Id.

Finally, the Service concluded, after analyzing the five

statutory endangerment factors, that the Western Great Lakes

segment was neither endangered nor threatened throughout all

or a significant portion of its range. 2011 Rule, 76 Fed. Reg.

at 81,721–81,723. The Service explained that existing rates of

mortality from disease and human causes had been insufficient

to prevent growth of the population, and that state plans

provided adequate monitoring of and protection for the wolf

segment. See, e.g., id. at 81,694; id. at 81,700.

2

14

The Humane Society filed suit alleging that the 2011 Rule

violated both the Endangered Species Act and the APA. The

district court agreed with the Humane Society and vacated the

2011 Rule, concluding that the Endangered Species Act does

not permit the Service to designate a segment only to

immediately delist it. See Humane Society of the U.S. v. Jewell,

76 F. Supp. 3d 69, 110 (D.D.C. 2014). While the district court

agreed that the statutory text was ambiguous, the court

concluded that the Service’s interpretation was unreasonable

given the structure, history, and purpose of the Act. Id. at 110–

113. In the district court’s view, the distinct population

segment designation could only function as a “one-way

ratchet,” allowing the Service to provide more, but not less,

protection for a species. Id. at 112.

The district court also rejected the Service’s argument that

it was simply revising the prior Minnesota wolf listing when it

created the Western Great Lakes segment. The court explained

that the Minnesota wolves had never been listed as a segment,

and that the newly created segment altered the original

geographic boundaries of the Minnesota wolf population.

Humane Society, 76 F. Supp. 3d at 114–115.

The district court further concluded that the rule was

arbitrary and capricious because the Service failed to address

how large losses in the gray wolf’s historical range affected the

determination that the Western Great Lakes segment was not

endangered or threatened. Humane Society, 76 F. Supp. 3d at

128–132.

Finally, the district court held that the rule was invalid

because the Service failed to adequately consider the threat to

wolves from disease and human-caused mortality and the

insufficiency of state regulatory measures to protect the wolves

15

after delisting. Humane Society, 76 F. Supp. 3d at 132–134.

The district court accordingly vacated the rule. Id. at 136–137.

II

The Service’s listing determinations are subject to review

under Section 706 of the APA, 5 U.S.C. § 706. See American

Wildlands v. Kempthorne, 530 F.3d 991, 997 (D.C. Cir. 2008).

Under that standard, we must overturn an agency decision if it

is “arbitrary, capricious, an abuse of discretion, or otherwise

not in accordance with law.” 5 U.S.C. § 706(2)(A).

We review the Service’s interpretation of the Endangered

Species Act under the familiar two-step Chevron framework.

See Chevron U.S.A., Inc. v. Natural Resources Def. Council,

Inc., 467 U.S. 837 (1984). First, we apply the “traditional tools

of statutory construction” to determine whether Congress has

directly spoken to the question at issue. Id. at 842–843 & n.9;

Central United Life Ins. v. Burwell, 827 F.3d 70, 73 (D.C. Cir.

2016). If the statute’s meaning is clear, the inquiry ends and

“we must give effect to the unambiguously expressed intent of

Congress.” Secretary of Labor, Mine Safety & Health Admin.

v. National Cement Co. of Cal., 494 F.3d 1066, 1073 (D.C. Cir.

2007) (internal quotation marks and citation omitted). If,

however, “the statute is silent or ambiguous with respect to the

specific issue,” then we will defer to the agency’s considered

interpretation of the statute if it is “reasonable.” Abington

Crest Nursing & Rehab. Ctr. v. Sebelius, 575 F.3d 717, 719

(D.C. Cir. 2009) (internal quotation marks and citation

omitted); see also United States v. Mead Corp., 533 U.S. 218,

227–229 (2001).

The central dispute in this case is whether the Endangered

Species Act permits the Service to carve out of an already-

listed species a “distinct population segment” for the purpose

16

of delisting that segment and withdrawing it from the Act’s

aegis. We hold that the Act permits such a designation, but

only when the Service first makes the proper findings.

A

This question of statutory interpretation starts with the

Endangered Species Act’s plain text. The Act extends its

protections to an endangered or threatened “species,” and then

defines such protected species to include “any distinct

population segment of any species of * * * wildlife[.]” 16

U.S.C. § 1532(16). The identification and application of the

Act to “distinct population segment[s]” thus falls

straightforwardly within the Service’s wheelhouse. That much

cannot be textually disputed.

The tougher question is whether that distinct population

segmentation process is, as the district court ruled, a one-way

ratchet that only allows the Service to extend the Act’s

protections to newly recognized groupings. See Humane

Society, 76 F. Supp. 3d at 112. Or can the Service, even after

a species as a whole has been identified as endangered or

threatened, cleave out a subset of that already-listed species for

delisting based on the segment’s recovery (or uplisting if it has

become distinctly imperiled)? Said another way, once a

species has been listed, must any changes in its listing status

occur species-wide or can the species and its status be

dissevered? As to that question, the statutory text is murkier.

The Endangered Species Act quite plainly allows—

actually, requires—the Service to periodically revisit and, as

warranted, revise the status of a listed species. Section

1533(c)(1) directs the Service to, “from time to time revise

each list * * * to reflect recent determinations, designations,

and revisions.” 16 U.S.C. § 1533(c)(1); see id. § 1533(a)(1),

17

(b)(1)(A). And Section 1533(c)(2) separately directs the

Service to “conduct, at least once every five years, a review of

all [then-listed] species,” and to “determine on the basis of such

review whether any such species should—(i) be removed from

such list; (ii) be changed in status from an endangered species

to a threatened species; or (iii) be changed in status from a

threatened species to an endangered species.” Id.

§ 1533(c)(2)(A), (B). Each decision made under those two

statutory provisions must rely upon the five statutorily

designated criteria for listing and the best available scientific

and commercial data. Id. § 1533(c)(1), (2); see id.

§ 1533(a)(1), (b)(1)(A).

Nothing in that statutory language forbids the recognition

of recovered distinct population segments within a listed

species. The Secretary’s authority to revise a listing under

Section 1533(c)(1) is generally unconditioned, as long as the

underlying determination on which the revision is based (here,

the finding of a distinct population segment) is grounded in the

five statutory listing factors and the best available scientific and

commercial data. See 16 U.S.C. § 1533(c)(1). To be sure,

subsection (c)(1) cross-references the best-evidence

requirement of Section 1533(b)(1)(A), which in turn directs the

Service to “make determinations * * * after conducting a

review of the status of the species,” id. § 1533(b)(1)(A)

(emphasis added). But that leaves textually unanswered the

central question of whether a review of “the species” can itself

result in the identification of a distinct population segment.

Section 1533(c)(2)’s quinquennial review provision offers

some textual support for the Humane Society’s argument that

a change in status must be made for the species as listed.

Subsection (c)(2) requires reconsideration of whether “such

species” as “included in a list” that is “in effect at the time of

such review” should be changed from endangered to

18

threatened, changed from threatened to endangered, or

removed from the list entirely. 16 U.S.C. § 1533(c)(2)

(emphasis added). “[S]uch species” would seem to require

review of the species’ status as listed.

But while that reading of the statute would be reasonable,

it is not ineluctable. To begin with, while subsection (c)(2)

prescribes what decisions the Service must make, its text does

not foreclose the Service from making additional status

decisions. In other words, nothing in the statutory language

indicates that the mandated decisions are a ceiling capping the

Service’s authority rather than just a minimum-requirements

floor. In addition, subsection (c)(2) does not detract from the

Service’s more open-ended revision authority under subsection

(c)(1).

The long and the short of all this is that the text of the

Endangered Species Act does not itself answer the question

whether the Service can designate a distinct population

segment from within an already-listed species.

B

Because the statute is “silent or ambiguous with respect to

the specific issue” at hand, the question before this court

becomes whether the Service’s interpretation is “based on a

permissible construction of the statute.” United States Sugar

Corp. v. EPA, 830 F.3d 579, 605 (D.C. Cir. 2016) (quoting

Chevron, 467 U.S. at 842–843). Generally, a “‘reasonable’

explanation of how an agency’s interpretation serves the

statute’s objectives is the stuff of which a ‘permissible’

construction is made[.]” Northpoint Tech., Ltd. v. FCC, 412

F.3d 145, 151 (D.C. Cir. 2005) (citation omitted). “[A]n

explanation that is ‘arbitrary, capricious, or manifestly contrary

to the statute,’ however, is not.” Id. (quoting Chevron, 467

19

U.S. at 844). Accordingly, this court must determine whether

the Service “has advanced a reasonable explanation for its

conclusion that the regulations serve * * * [the Act’s]

objectives,” Chevron, 467 U.S. at 863, and whether that

“interpretation * * * is at least reasonable in light of any

ambiguities in the statute[,]” District of Columbia. v.

Department of Labor, 819 F.3d 444, 449 (D.C. Cir. 2016). See

United States Sugar Corp., 830 F.3d at 608 (regulation must

reflect a “permissible reading” of the statute).

The Service’s interpretation of Section 1533(c)(1) as

allowing for the designation of a distinct population segment

within a listed species is a reasonable reading of statutory text

and—when properly undertaken, see Part II.C, infra—does not

contravene the purposes of the Endangered Species Act.

With respect to the statutory language, the Service’s

position makes textual sense because subsection (c)(1) itself

expressly contemplates that new “designations” and

“determinations” could intervene that would require

“revis[ing]” an extant listing. 16 U.S.C. § 1533(c)(1).

Furthermore, the listing of an animal at the species-wide level

can reasonably be understood to include within it a listing of

all subspecies and segments within that species. That is to say,

the Service’s initial listing of all gray wolves in North America

necessarily listed all possible segments and subspecies within

that grouping. See Solicitor’s Opinion 7; 2011 Rule, 76 Fed.

Reg. at 81,670, 81,683. So understood, the Service’s

interpretation comports with Section 1533(c)(2)’s textual

requirement that listing changes apply only to species that are

already “included in a list * * * [that] is in effect,” at the time

of the Service’s five-year status review, id. § 1533(c)(2).

In addition, the statute requires the Service to attend to

both parts of the listing process—the initial listing, and the

20

revision or delisting—with equal care. After all, both

subsections (c)(1) and (c)(2) require the Service to rely on the

same factors and best evidence that were first used to list a

species when downlisting, delisting, uplisting, or otherwise

revising that species’ status. Nothing in the statutory text

compels the Service to put a thumb on the scale in favor of

listing, nor does the text require the Service to temporize when

the best evidence indicates that a revision is warranted.

Indeed, the statutory text leaves room for the Service, at

the initial stage, to list most of a species as threatened, while

dividing out a distinct population segment for listing as

endangered based on its unique circumstances and conditions.

That same language would also permit the Service at the outset

to list a segment as threatened even if the remainder of the

taxon is endangered. See 16 U.S.C. § 1532(16) (defining

“species” in non-exhaustive terms); cf. Modesto Irrigation

Dist. v. Gutierrez, 619 F.3d 1024, 1031–1032 (9th Cir. 2010)

(Service need not place interbreeding populations of a species

in the same distinct population segment); Trout Unlimited v.

Lohn, 559 F.3d 946, 959–961 (9th Cir. 2009) (upholding the

Service’s practice of distinguishing between geographically

co-located hatchery and natural populations of the same

taxonomic species when listing).

Because the statutory text and purposes can be read to

permit such a divided listing on the front end of the listing

process, the Service likewise can reasonably read the statute to

permit similar determinations at the revision stage. The

statutory text does not have to be treated like a one-way street

leading only to uplisting.

The Service’s position is also consonant with the purposes

of the Endangered Species Act, which is to devote needed

resources to the protection of endangered and threatened

21

species, while abating the Act’s comprehensive protections

when a species—defined to include a distinct population

segment—is recovered. See, e.g., 16 U.S.C. § 1531 (statutory

purpose is to provide for the conservation of species when they

are “endangered” or “threatened”); id. § 1533(b)(2) (directing

the Service to take into account the “economic impact, the

impact on national security, and any other relevant impact”

when designating “any particular area as critical habitat”);

Defenders of Wildlife v. Norton, 258 F.3d 1136, 1144 (9th Cir.

2001) (noting Congress’s desire to allow the Service “more

flexibility in [its] approach to wildlife management”). The

Service’s interpretation ensures that the most resources can be

brought to bear where a species continues to be threatened or

endangered. See Solicitor’s Opinion 18–19; 2011 Rule, 76

Fed. Reg. at 81,670, 81,683. In that regard, the Act’s direction

to the Service to evaluate the status of not just species, but

subspecies and segments, 16 U.S.C. § 1532(16), signals

Congress’s intent to target the Act’s provisions where needed,

rather than to require the woodenly undifferentiated treatment

of all members of a taxonomic species regardless of how their

actual status and condition might change over time. 3

Another purpose of the Endangered Species Act is to foster

state cooperation in the conservation of threatened or

endangered species. See 16 U.S.C. § 1531(a)(5) (One purpose

of the Act is “encouraging the States * * * to develop and

maintain conservation programs which meet national and

international standards[.]”); see also Solicitor’s Opinion 16–17

3

See also 16 U.S.C. § 1539(j) (providing for the discretionary

use of experimental populations in species recovery); id. § 1539(a)

(allowing the Service to issue permits for the “taking” of listed

species in specified circumstances); Loggerhead Turtle v. Council of

Volusia Cty., 148 F.3d 1231, 1260 (11th Cir. 1998) (describing

“flexible” nature of the Service’s authority to allow “incidental

takes”).

22

(“Removing [Endangered Species Act] protections for

recovered [Distinct Population Segments] of listed species

reinforces the strong public policy goal of federal-State

cooperation[.]”); 2011 Rule, 76 Fed. Reg. at 81,670, 81,683

(incorporating the views expressed in the Solicitor’s Opinion). 4

Because the locations of distinct population segments not

uncommonly correspond with geographical lines, empowering

the Service to alter the listing status of segments rewards those

States that most actively encourage and promote species

recovery within their jurisdictions. On the other hand,

continuing to rigidly enforce the Act’s stringent protections in

the face of such success just because recovery has lagged

elsewhere would discourage robust cooperation. The Service’s

interpretation thus reasonably “encourage[s] the States * * *

through * * * a system of incentives.” 16 U.S.C. § 1531(a)(5).

The Humane Society argues that Service action under the

Act “must be, first and foremost, to provide protections to

endangered or threatened species.” Humane Society’s Br. 33.

True enough. But that premise does nothing to answer the

specific question of whether the Service is permitted to tailor

its protections to where they are most needed.

Relatedly, the Humane Society argues that designating a

segment to delist it violates the Service’s formal Segment

4

See also 16 U.S.C § 1533(b)(1)(A) (directing the Service to

take into account “efforts, if any, being made by any State or foreign

nation, or any political subdivision of a State or foreign nation, to

protect such species, whether by predator control, protection of

habitat and food supply, or other conservation practices, within any

area under its jurisdiction, or on the high seas,” when determining

whether to list a species).

23

Policy, 61 Fed. Reg. at 4,724–4,725. Aspects of that Policy

certainly underscore its protective purpose. The Service has

explained that the identification of distinct population

segments should “be aimed at carrying out the purposes of the

Act,” including “to provide a means whereby the ecosystems

upon which endangered species and threatened species depend

may be conserved, [and] to provide a program for the

conservation of such endangered species and threatened

species.” Id. at 4,722 (internal quotation mark and citation

omitted). Indeed, some of the Policy’s criteria for

“significance”—which a population must possess to qualify as

a segment—would seem to most often be relevant to enhancing

protections for animals. For example, it would not make much

sense to downlist or delist a population that “represents the only

surviving natural occurrence of a taxon that may be more

abundant elsewhere as an introduced population outside its

historic range.” Id. at 4,725.

On the other hand, other aspects of the Segment Policy

plainly work in both the listing and delisting directions. See

Segment Policy, 61 Fed. Reg. at 4,722 (describing segments as

being used “for the purposes of listing, delisting, and

reclassifying species”) (emphasis added); id. at 4,725 (referring

to the enumerated segment factors as “apply[ing] similarly for

addition to the lists[,] * * * reclassification, and removal from

the lists”) (emphasis added); id. (identifying the Segment

Policy as guiding “the evaluation of distinct vertebrate

population segments for the purposes of listing, delisting, and

reclassifying under the Act”) (emphasis added).

The Solicitor’s Opinion, formally adopted by the Service,

has now explicitly interpreted the Act to allow the segment tool

for delisting. See Solicitor’s Opinion 3–5; 2011 Rule, 76 Fed.

Reg. at 81,670, 81,683. See also Encino Motorcars, LLC v.

Navarro, 136 S. Ct. 2117, 2125 (2016) (“Agencies are free to

24

change their existing policies so long as they provide a

reasoned explanation for the change.”).

The Humane Society also argues that designating a

segment to delist it violates the specific process set out in the

Segment Policy, 61 Fed. Reg. at 4,725. That Policy identifies

three factors to be considered in designating and listing a

segment: the “discreteness,” “significance,” and “conservation

status” of a population. Id. The Humane Society reads that

provision to require findings that a population is discrete,

significant, and has a conservation status of threatened or

endangered before the Service can designate it.

But the far more natural reading of the Policy is that it only

requires a determination that the potential segment is

threatened or endangered prior to listing, not prior to the

designation of the segment itself. See Segment Policy, 61 Fed.

Reg. at 4,725. The Policy specifically sets out identification of

the segment’s conservation status as an independent step that

follows after a segment has been identified as a distinct

population segment because of its discreteness and

significance. See id. (“Status: If a population segment is

discrete and significant (i.e., it is a distinct population segment)

its evaluation for endangered or threatened status will be based

on the Act’s definitions of those terms and a review of the

factors enumerated in [Section 1533(a)].”) (second emphasis

added). The Service’s decision in this case thus did not

contradict its Segment Policy. 5

5

Because the Service has the better and more natural reading

of its Segment Policy, we do not address whether the Service’s

interpretation is owed deference under Auer v. Robbins, 519 U.S. 452

(1997). Cf. Baptist Mem’l Hosp.-Golden Triangle v. Sebelius, 566

F.3d 226, 228 (D.C. Cir. 2009) (“We need not tackle the question of

[Auer] deference: We agree with the Board’s interpretation of its

25

* * * * *

“When it enacted the [Endangered Species Act], Congress

delegated broad administrative and interpretive power to the

[Service].” Babbitt v. Sweet Home Chapter of Communities for

a Great Oregon, 515 U.S. 687, 708 (1995). And “[t]he task of

defining and listing endangered and threatened species requires

an expertise and attention to detail that exceeds the normal

province of Congress.” Id. Given the ambiguity of the

statutory text, the Humane Society’s proffered interpretation of

the Act as favoring the use of segments in a protective manner

may very well be reasonable. But our task under Chevron is

not to pick from amongst reasonable options. Our task is

simply to determine whether the Service’s interpretation of the

ambiguous language is reasonable. We hold that the Service

permissibly concluded that the Endangered Species Act allows

the identification of a distinct population segment within an

already-listed species, and further allows the assignment of a

different conservation status to that segment if the statutory

criteria for uplisting, downlisting, or delisting are met.

C

Holding that the Service has the legal authority to identify

a distinct population segment from within an already-listed

species does not mean it did so properly here. In fact, it did

not. The fundamental error in the Service’s decision is that, in

evaluating whether gray wolves in the Western Great Lakes

region are a “distinct” population segment, the Service failed

to address the impact that extraction of the segment would have

Instructions regardless of what, if any, deference we owe it in this

case.”); see also Talk America, Inc. v. Michigan Bell Tel. Co., 564

U.S. 50, 67 (2011) (Scalia, J., concurring) (“In this suit I have no

need to rely on Auer deference, because I believe the [agency’s]

interpretation is the fairest reading of the orders in question.”).

26

on the legal status of the remaining wolves in the already-listed

species. More specifically, the Service cannot find that a

population segment is distinct—in the Service’s words, that it

is severable because it is “discrete” and “significant”—without

determining whether the remnant itself remains a species so

that its own status under the Act will continue as needed.

1

The Endangered Species Act’s text requires the Service,

when reviewing and redetermining the status of a species, to

look at the whole picture of the listed species, not just a

segment of it. Section 1533(c)(2)(A) requires that the review

cover the “species included in a list.” 16 U.S.C.

§ 1533(c)(2)(A); see also id. § 1533(c)(1), (b)(1)(A) (directing

the Service, when revising the status of a species, to “make [its]

determinations * * * after conducting a review of the status of

the species” as listed) (emphasis added); see also id.

§ 1533(c)(2)(B). As the Service itself argues, that review can

reasonably be read to include any and all of the composite

segments or subspecies that might be included within a

taxonomically listed species. See Solicitor’s Opinion 7–8 &

n.10; 2011 Rule, 76 Fed. Reg. at 81,670, 81,683. Thus, when

a species is already listed, the Service cannot review a single

segment with blinders on, ignoring the continuing status of the

species’ remnant. The statute requires a comprehensive review

of the entire listed species and its continuing status. Having

started the process, the Service cannot call it quits upon finding

a single distinct population segment.

The Service’s definition of a “distinct population segment”

confirms the point. See Segment Policy, 61 Fed. Reg. at 4,725.

The Service’s two critical criteria for such a segment are

“discreteness” and “significance.” Id. Both of those factors

must be met before a segment can be recognized.

27

To start, the Service looks at the “[d]iscreteness of the

population segment in relation to the remainder of the species

to which it belongs.” Segment Policy, 61 Fed. Reg. at 4,725.

More specifically, to be distinct, a segment must be “markedly

separated” out “from other populations of the same taxon as a

consequence of physical, physiological, ecological, or

behavioral factors.” Id. Those two factors clearly envision a

comparative analysis of a potential segment to the remnant and

consideration of the segment’s independent severability. 6

With respect to the “significance” part of the test, the

Service looks to such factors as whether the segment:

(i) persists in an “ecological setting” that is “unusual or unique

for the taxon”; (ii) is the “only surviving natural occurrence of

a taxon”; (iii) has genetic characteristics that are “markedly”

different from the rest of the taxon; or (iv) would cause a

“significant gap” in the taxon’s range if lost. Segment Policy,

61 Fed. Reg. at 4,725. Each of those factors measures a

potential segment’s “significance” in relation to the “taxon.”

That means that an evaluation of “significance” presupposes

that there is a still-existing taxon against which to compare the

potential segment. Indeed, without an evaluation of the taxon

(both pre- and post-designation of the proposed segment), the

Service could not in any meaningful way evaluate the proposed

segment’s significance to that taxon.

Requiring the Service to look at the implications for both

the segment and the remnant during the delisting, uplisting, or

downlisting process thus flows naturally from the Endangered

Species Act’s text and the Service’s own Segment Policy.

6

International borders can also sometimes help to identify a

discrete population segment. Segment Policy, 61 Fed. Reg. at 4,725.

That consideration is not at issue in this case.

28

Even more importantly, omitting analysis of the effect of

designation on the already-listed species would divest the

extant listing of legal force. The segment-designation process

is meant to be “sparing[]” in its use. Segment Policy, 61 Fed.

Reg. at 4,724. Yet the Service’s disregard of the remnant’s

status would turn that sparing segment process into a backdoor

route to the de facto delisting of already-listed species, in open

defiance of the Endangered Species Act’s specifically

enumerated requirements for delisting. See 16 U.S.C.

§ 1533(a)(1) (listing five mandatory criteria for altering a

listing). Accordingly, as a matter of plain statutory design, the

act of designating a segment cannot in one fell swoop make an

already-listed species an unlisted and unlistable non-species,

“sidestep[ping]” the process “Congress has plainly” prescribed

for delisting. See Natural Resources Def. Council v. EPA, 489

F.3d 1364, 1372 (D.C. Cir. 2007); see also Whitman v.

American Trucking Ass’ns, 531 U.S. 457, 485 (2001) (“[An

agency] may not construe the statute in a way that completely

nullifies textually applicable provisions meant to limit its

discretion.”). Instead, the Service must make it part and parcel

of its segment analysis to ensure that the remnant, if still

endangered or threatened, remains protectable under the

Endangered Species Act.

2

In designating the Western Great Lakes wolves as a

distinct population segment, the Service looked only at the

characteristics of the Western Great Lakes segment in a

vacuum, ignoring the second step of determining whether both

the segment and the remainder of the already-listed wolves

would have mutually independent statuses as species.

29

Prior to the 2011 Rule designating the Western Great

Lakes segment, the Service had made two listings of gray

wolves: those in Minnesota that were found to be threatened,

and those wolves in the lower forty-eight states outside of

Minnesota that were determined to be an endangered species.

When the Service attempted to carve the Western Great Lakes

segment out of the latter, it left the remnant of that already-

statutorily-protected group in legal limbo without any

determination that the gray wolves in the continental United

States outside of the Western Great Lakes segment were

themselves a species, subspecies, or segment that could

continue to be protected under the Endangered Species Act.

Certainly “gray wolves outside the Western Great Lakes

segment” have never been recognized as a taxonomic species.

The Service also failed to analyze whether “gray wolves

outside the Western Great Lakes segment” are either a

subspecies or a segment. 7 Absent such a determination, the

Service has left entirely unexplained how the remaining

wolves’ existing endangered status would continue. Nor did

the Service make any finding that the remnant was no longer

endangered under the statutory listing criteria.

Worse still, the Service has announced that, with the

Western Great Lakes segment carved out, the remnant is no

longer a protectable “species” and has proposed its delisting for

that reason alone. See Removing the Gray Wolf (Canis lupus)

From the List of Endangered and Threatened Wildlife and

Maintaining Protections for the Mexican Wolf (Canis lupus

baileyi) by Listing It as Endangered, 78 Fed. Reg. 35,664,

35,668 (June 13, 2013) (“We conclude that the current C. lupus

[gray wolf] entity is not a valid species under the Act and now

7

We take no position on whether such a designation by the

Service would be appropriate. See Florida Power & Light Co. v.

Lorion, 470 U.S. 729, 744 (1985).

30

propose to remove this entity from the List[.]”). The Service

did not deny that position at oral argument. See Oral Arg. Tr.

85–90.

The Service’s power is to designate genuinely discrete

population segments; it is not to delist an already-protected

species by balkanization. The Service cannot circumvent the

Endangered Species Act’s explicit delisting standards by riving

an existing listing into a recovered sub-group and a leftover

group that becomes an orphan to the law. Such a statutory

dodge is the essence of arbitrary-and-capricious and ill-

reasoned agency action. See Ragsdale v. Wolverine World

Wide, Inc., 535 U.S. 81, 91–92, 94 (2002) (invalidating agency

action that constituted an “end run around important [statutory]

limitations” and thus “contravene[d] Congress’ will” and

“subvert[ed] the careful balance” of the statute).

The Service argues in the alternative that it did not

designate a new segment, but rather only revised the 1978

Minnesota gray wolf segment and then delisted it. We are

doubtful that the Service’s action can be fairly characterized as

a revision, especially given the fact the purported revision

roped-in wolf populations outside of the original Minnesota

population. See 2011 Rule, 76 Fed. Reg. at 81,678–81,679,

81,716; 1978 Rule, 43 Fed. Reg. at 9,608 (“There is also a

group [of wolves] on Isle Royale in Lake Superior, and

possibly a few scattered individuals in northern Michigan and

Wisconsin.”). By bringing within the scope of the segment

those outside-Minnesota wolves, the Service’s “revision” of

the Minnesota gray wolf segment is in fact a revamping of the

entire gray wolf listing, including the non-Minnesota

population listing. But we need not decide that question.

Whether labeled a revision or a segment-designation, the flaw

is the same: the failure to address the status of the remnant is

fatal.

31

III

Under the Endangered Species Act, the determination of a

species’ endangered or threatened status turns on the threats

that the species faces “throughout all or a significant portion of

its range.” 16 U.S.C. § 1532(6), (20). The Service concluded

that “range” refers to the species’ current range at the time its

status is evaluated or reevaluated for listing. See 2011 Rule, 76

Fed. Reg. at 81,721–81,722. The district court held that the

Service’s decision to delist the Western Great Lakes segment

failed to adequately address the wolves’ loss of historical

range. Humane Society, 76 F. Supp. 3d at 128–132. Because

the Service’s interpretation of “range” as focusing on “current

range” is reasonable, we uphold it. But because the Service

categorically excluded the effects of loss of historical range

from its analysis, we hold that the Service’s conclusion about

the ongoing threat to the Western Great Lakes segment within

its current rage was insufficiently reasoned, and therefore

arbitrary and capricious.

A

Under Chevron, we ask first whether the Endangered

Species Act speaks directly to the meaning of “range” and, if it

does not, we must evaluate the reasonableness of the Service’s

interpretation. See 467 U.S. at 842–843.

The Endangered Species Act does not itself define

“range.” See 16 U.S.C. § 1532. The definitions of

“endangered” and “threatened” species, however, do use the

present tense “is” to refer to the status of the species within its

range. Id. § 1532(6), (20). That seems to accord with the

Service’s position that “range” refers to “current range.” See

Sherley v. Sebelius, 644 F.3d 388, 394 (D.C. Cir. 2011) (“The

use of the present tense in a statute strongly suggests it does not

extend to past actions.”). But see McNeill v. United States, 563

32

U.S. 816, 821–822 (2011) (Congress has “used the present

tense to refer to past convictions”).

Still, focusing on verb tense does not get the Service very

far. That is because the placement of “is” in the definitions

seems most naturally to require that the species currently be

endangered or threatened within its range, not to dictate the

temporal scope of geographical evidence the Service is to

consider. A species can be found to be endangered now—“is

in danger of extinction,” 16 U.S.C. § 1532(6) (emphasis

added)—based just as easily on threats to the species

throughout its historical range as on threats throughout its

contemporary range. Cf. Defenders of Wildlife v. Norton, 258

F.3d 1136, 1145 (9th Cir. 2001) (“[A] species can be extinct

‘throughout * * * a significant portion of its range’ if there are

major geographical areas in which it is no longer viable but

once was.”) (second alteration in original).

Outside of its use in the definitions of “endangered” and

“threatened” species, “range” appears only three times in the

Act. The term first appears in Section 1533(a), which lists “the

present or threatened destruction, modification, or curtailment

of [a species’] habitat or range,” as one of several factors for

the Service to consider in determining “endangered” or

“threatened” status. 16 U.S.C. § 1533(a)(1)(A). The term

appears a few subsections later in Section 1533(c), which

mandates that the listing of a species as endangered or

threatened shall “specify with respect to each * * * species

over what portion of its range it is endangered or threatened,

and specify any critical habitat within such range.” Id.

§ 1533(c)(1). Neither of those usages casts material light on

the meaning of “range” because the two references are as

textually indeterminate as the initial use of the term in Section

1532.

33

The third place that “range” appears is in Section 1539(j),

which provides that the Secretary may authorize the release of

any population of an endangered or threatened species “outside

the current range of such species if the Secretary determines

that such release will further the conservation of such species.”

16 U.S.C. § 1539(j)(2)(A). That provision cuts both ways. On

the one hand, it could be argued that, if “range” already means

current range, then the adjectival addition of “current” in

Section 1539(j) would be redundant. On the other hand, the

use of “current range” in Section 1539(j) could also be read to

corroborate the Service’s view, since “current range” in

Section 1539(j) may refer to the listed range of the endangered

or threatened species. See id. § 1539(j)(2)(A).

Dictionary definitions do not illuminate the meaning of

“range” either. As a biological and zoological term of art,

“range” is commonly defined as a geographical reference to the

physical area in which a species lives or occurs. See, e.g., 8

THE OXFORD ENGLISH DICTIONARY 139 (def. 7) (1933)

(defining “range” as: “[t]he geographical area over which a

certain plant or animal is distributed”). The most that can be

said is that such dictionary definitions employ the present

tense. But that may reflect the nature of dictionary definitions

generally, rather than suggest any contextual meaning within

the Endangered Species Act. 8

Accordingly, traditional rules of statutory construction do

not answer the question of whether “range” means current or

historical range. Indeed, the Service and the Humane Society

both acknowledge that the Act leaves open the possibility that

“range” may refer to either current or historical range. See

8

None of the parties suggests that legislative history illuminates

the meaning of “range.”

34

Service’s Br. 68–69; Humane Society’s Br. 47–48. 9 The

question then becomes whether the Service’s interpretation of

“range” as “current range” “is based on a permissible

construction of the statute.” Mayo Found. for Med. Educ. &

Research v. United States, 562 U.S. 44, 54 (2011) (quoting

Chevron, 467 U.S. at 843). It is.

Although the statute itself does not indicate the meaning

of “range,” the Service’s interpretation is at least consistent

with the Endangered Species Act’s use of the present tense in

provisions discussing the species’ range, 16 U.S.C. § 1532(6),

(20). And it also accords with Section 1539(j)(2)(A)’s use of

“current range” in reference to a species’ listed range. In

addition, focusing on the species’ survival in the range it

currently occupies is consonant with the purposes of the

Endangered Species Act, because the threats that a species

confronts where it currently lives often affect its continued

survival the most and thus bear influentially on whether it

should be listed. See 2011 Rule, 76 Fed. Reg. at 81,722–81,723

(discussing threats in areas where the Western Great Lakes

wolf population currently lives).

For those reasons, we conclude that the Service’s

interpretation of “range” to focus on a species’ current range is

a reasonable interpretation of the Act.

B

9

Other courts have recognized the ambiguity of the broader

statutory phrase “in danger of extinction throughout * * * a

significant portion of its range,” see Defenders of Wildlife, 258 F.3d

at 1141, or “significant portion of its range,” see Colorado River

Cutthroat Trout v. Salazar, 898 F. Supp. 2d 191, 201–203 (D.D.C.

2012); WildEarth Guardians v. Salazar, 741 F. Supp. 2d 89, 99–100

(D.D.C. 2010).

35

As with the Service’s designation of distinct population

segments, the rub in this case is not with the Service’s

interpretation of the statute, but with its application of the

statute to the record at hand. While analysis of the

reasonableness of agency action “under Chevron Step Two and

arbitrary and capricious review is often the same,”

Pharmaceutical Research & Mfrs. of America v. Federal Trade

Comm’n, 790 F.3d 198, 209 (D.C. Cir. 2015) (internal

quotation marks and citation omitted), the Venn diagram of the

two inquiries is not a circle. The question thus remains whether

the agency arbitrarily and capriciously “‘failed to consider an

important aspect of the problem’ it faces.” SecurityPoint

Holdings, Inc. v. Transportation Sec. Admin., 769 F.3d 1184,

1187 (D.C. Cir. 2014) (quoting Motor Vehicle Mfrs. Ass’n of

the U.S. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43

(1983)).

We hold that the Service’s analysis of the status of the

Western Great Lakes segment within its current range wrongly

omitted all consideration of lost historical range. Just because

the Endangered Species Act does not compel the Service to

interpret “range” to mean historical range, that does not mean

that the Service can brush off a substantial loss of historical

range as irrelevant to the species’ endangered or threatened

status. So says the Service itself: The Service’s Range Policy

is explicit that a species may be “endangered or threatened

throughout all or a significant portion of its current range

because [a] loss of historical range is so substantial that it

undermines the viability of the species as it exists today.”

Range Policy, 79 Fed. Reg. at 37,584 (emphasis added).

That is an eminently sensible approach. Range loss can

“result[] in a species for which distribution and abundance is

restricted, gene flow is inhibited, or population redundancy is

reduced to such a level that the entity is now vulnerable to

36

extinction or likely to become so within the foreseeable future

throughout all or a significant portion of its current range.”

Range Policy, 79 Fed. Reg. at 37,584. In addition, “a species

with a reduced range is at greater risk of all or most of its

populations being affected by a catastrophic event such as a

hurricane or fire.” Id.

In other words, an adequate evaluation of the threats

confronting the survival of a species within its current range

requires looking at more than just the current moment in time.

The Service, consistent with its own Range Policy, also needs

to consider the scope of the species’ historical range, and the

impact that material contraction or relocation might indicate for

survival within a currently constricted or confined range.

There is, moreover, no question in this case that “gray

wolves have been extirpated from most of the southern portions

of their historical North American range.” 2011 Rule, 76 Fed.

Reg. at 81,672. The Humane Society estimates that 95% of the

gray wolf’s historical range has disappeared. Humane

Society’s Br. 48, 50. The Service does not dispute that figure.

Despite immense losses in the gray wolves’ historical

range—including the historical range of those wolves now

occupying the Western Great Lakes area—the Service nowhere

analyzed the impact of that loss on the survival of the gray

wolves as a whole, the gray wolves remnant, or the Western

Great Lakes segment. Such a failure to address “an important

aspect of the problem” that is factually substantiated in the

record is unreasoned, arbitrary, and capricious decisionmaking.

State Farm, 463 U.S. at 43; see also AEP Tex. N. Co. v. Surface

Transp. Bd., 609 F.3d 432, 441 (D.C. Cir. 2010) (agency acted

arbitrarily and capriciously when it “failed to address the

unique circumstances of” an issue).

37

The Service does not deny the gap in its analysis. Instead,

the Service points to its determination that the Western Great

Lakes segment would remain viable in key portions of the

Western Great Lakes area. See 2011 Rule, 76 Fed. Reg. at

81,722–81,723. That is a non sequitur. As the Range Policy

explained, consideration of material changes in a species’

historical range is critical to a reliable assessment of

sustainability within the current range. So whatever the

Service prognosticates about future viability in certain portions

of the current range cannot be reliably reasoned if it was made

in a historical vacuum. An important factor—the possible

enduring consequences of significant loss of historical range—

was left out of the analysis all together.

The Service also argues that the Act does not require the

restoration of a species to its entire historical range. See

Service’s Reply Br. 27–29. Okay. But giving adequate

consideration to the effects of large losses of historical range

on a species’ survival going forward has nothing to do with

where geographically a species must be restored. The only

obligation at issue here is for the Service to contend with the

implications of massive range loss for the species’ endangered

or threatened status within its current environment.

Finally, we note that, in undertaking that omitted analysis

on remand, the Service will have to grapple with predicate

questions that the Service has evaded thus far, such as:

• Defining the physical boundaries of the relevant

historical range, compare 2011 Rule, 76 Fed. Reg.

at 81,672 (noting that “[g]ray wolves once lived

throughout most of North America”), with id. at

81,689 (finding that this particular population of

gray “wolves historically occupied the entire

Midwest”), and id. at 81,725 (describing the gray

38

wolf’s historical range as the entire “Holarctic”

region); see also id. at 81,687 (noting that research

into “whether gray wolves * * * historically

occupied portions of the eastern United States is

ongoing”); and

• Establishing the appropriate timeframe for

measuring a species’ historical range, such as the

enactment of the 1973 Endangered Species Act,

the enactment of its predecessor statutes in 1966

and 1969, the Nation’s founding, or some other

date.

In sum, because the undisputedly vast loss of historical

range is a salient factor in determining the endangered or

threatened status of the Western Great Lakes segment and the

remnant population within their current ranges, the Service’s

wholesale failure to address that factor renders the Service’s

decision unreasoned, arbitrary, and capricious.

IV

The Humane Society also argues that the final rule failed

adequately (i) to explain why the wolf population’s combined

mortality from humans and disease is not a continuing threat to

the species’ existence, and (ii) to address the lack of adequate

plan provisions or other protections for the gray wolves in the

seven States that make up the Western Great Lakes area.

Neither argument succeeds.

A

With respect to the combined threat to the gray wolves’

survival from disease and human-caused death, the record

reflects that the Service adequately wrestled with both

problems and grounded its decision in substantial evidence.

39

1

With respect to disease mortality, the 2011 Rule addressed

five diseases that afflict the Western Great Lakes gray wolves:

canine parovirus, sarcoptic mange, lyme, dog louse, and canine

distemper virus. The Rule also looked at the possibility of

other diseases entering the wolf population. 2011 Rule, 76 Fed.

Reg. at 81,694–81,698. The Service’s analysis was grounded

in scientific literature specifically analyzing the history and

impact of disease on the gray wolf population.

For instance, the Service explained that there was “no

evidence” that canine parovirus “caused a population decline

or has had a significant impact on the recovery of the

Minnesota wolf population.” 2011 Rule, 76 Fed. Reg. at

81,694. While some studies suggested that canine parovirus

had reduced pup survival from 1984 to 2004, the Service found

that there had actually been an increase in pup survival since

1995. Id. Notably, data in Wisconsin showed only a single

pup death attributable to canine parovirus since 2001, id., and

no such deaths in Michigan, id. at 81,695.

With respect to sarcoptic mange, the Service determined

that mange mortality was “stabilizing or perhaps declining in

Wisconsin.” 2011 Rule, 76 Fed. Reg. at 81,695. The Service

pointed to studies indicating that mange infection had not

increased in Minnesota since 2003, and had in fact declined

from 17% in 2006 to 10% in 2008. Id. at 81,696. As for lyme

disease and dog louse, the Service reported that there had been

no confirmed deaths in the Minnesota wolf population from

dog louse and no reports of clinical symptoms of lyme disease.

Id. Finally, with respect to canine distemper virus, the Service

relied on scientific studies that “predict periodic short-term

declines * * * but no long-term threat to the wolf population”

from the disease. Id.

40

The Service also acknowledged the possibility that new

diseases might arise, but concluded there was no sufficiently

concrete risk to threaten the gray wolf’s survival. 2011 Rule,

76 Fed. Reg. at 81,696. In that regard, the Service explained

that Minnesota’s, Michigan’s, and Wisconsin’s state plans all

provided for the continued monitoring of dead wolves and

testing of live-captured wolves and wolf feces to detect any

new diseases that might require intervention. Id. at 81,697.

Looking at the collective threat from disease, the Service

concluded that “the overall trend for wolf populations in the

[Western Great Lakes segment] continues to be upward.” Id.

at 81,698. The Service added that delisting the wolves “will

not significantly change the incidence or impacts of disease and

parasites on these wolves.” Id.

The Service’s judgment was corroborated through peer

review by a veterinary pathologist specializing in wolf disease

and mortality. The pathologist concluded that the proposed

rule “definitely contain[ed] an accurate, comprehensive

synthesis of published and unpublished data on disease and

predation threats to the Western Great Lakes * * * wolf

populations.” J.A. 881. She further concurred that “wolf

populations have grown despite introductions of new

diseases,” and that “all evidence indicate[d] that [diseases] are

not likely to endanger the [Western Great Lake] wolf

populations if delisted.” Id.

2

The Service’s analysis of human-caused mortality too was

satisfactory. Human-caused mortality for wolves comes in

three forms: fatal accidents (often involving vehicles), legal

depredation programs, and intentional illegal killings.

The Service’s 2011 Rule studied human-caused mortality

in detail. The Service reviewed existing mortality data and

41

acknowledged that humans were responsible for 56% of

diagnosed deaths of radio-collared wolves in Wisconsin from

1979 to 2009, 69% of such deaths in Minnesota from 1994 to

2005, and 75% of such deaths in the Upper Peninsula of

Michigan from 1960 to 1997. 2011 Rule, 76 Fed. Reg. at

81,698–81,699.

The Service nevertheless concluded that human-caused

mortality was not a significant threat to the wolf’s survival, as

shown by the resilient growth of the gray wolf population

despite the human-caused deaths. “As long as other mortality

factors do not increase significantly,” the Service concluded,

and “monitoring is adequate to document, and if necessary

counteract, the effects of excessive human-caused mortality

should that occur, * * * [the] wolf population will not decline

to nonviable levels” because of human-caused mortality. 2011

Rule, 76 Fed. Reg. at 81,700 (citation omitted).

The Service further reasoned that delisting the segment of

gray wolves would not affect the rate of human-caused

mortality. That is because accidental and depredation deaths

are most directly tied to the wolves’ proximity to areas densely

populated by humans. See 2011 Rule, 76 Fed. Reg. at 81,700

(“[A] continuing increase in wolf mortalities from vehicle

collisions, both in actual numbers and as a percent of total

diagnosed mortalities, is expected as wolves continue their

colonization of areas with more human developments and a

denser network of roads and vehicle traffic.”). Additionally,

the Service looked to Minnesota depredation data from 2007

and 2008 (the time when the Western Great Lakes wolf

population was temporarily delisted under the now-vacated

2007 Rule), and found that the rates of depredation deaths did

not change materially from before the wolves were delisted. Id.

at 81,704 (noting that 133 Minnesota wolves were killed in

2007 and 143 wolves in 2008, compared to 134 in 2005 and

42

122 in 2006). The Service further found that the Western Great

Lakes wolf population continued to grow despite the increase

in depredation deaths in 2007 and 2008 in Wisconsin and

Michigan. See id. at 81,708 (noting that the Wisconsin wolf

population increased 12% between 2008 and 2009); id. at

81,712 (noting that the Michigan wolf population grew 11%

between 2008 and 2009).

The Service also addressed the problem of illegal killings.

The Service candidly acknowledged the limited data available

since such killings “generally occur in remote locations and the

evidence is easily concealed[.]” Final Rule, 76 Fed. Reg. at

81,698. Nevertheless, the data that the Service was able to

collect indicated that the number and proportion of wolves

killed illegally in Wisconsin declined while the gray wolf was

delisted under the later-vacated 2007 Rule. See id. at 81,696

(showing 17 of 72 wolves found dead in 2006 had been killed

illegally and 20 of 72 in 2009, compared to 10 of 90 in 2007

and 14 of 94 in 2008); id. (illegal killings were 67% of all

mortality in 2006, 62% in 2006, and 44% in 2010 compared to

19% in 2007 and 23% in 2008). Other than that, the Service

concluded that it was “not possible at this time to determine if

human-caused mortality (apart from mortalities from

depredation control) has significantly changed over the nearly

35-year period that the gray wolf has been listed as threatened

or endangered.” Id. at 81,700.

What ultimately proved most relevant to the Service was

that, over all of the studied time periods, “all sources of wolf

mortality, including legal (for example, depredation control)

and illegal human-caused mortality, have not been of sufficient

magnitude to stop the continuing growth of the wolf

population[.]” 2011 Rule, 76 Fed. Reg. at 81,700; see also id.

(“Despite human-caused mortalities of wolves in Minnesota,

43

Wisconsin, and Michigan, these wolf populations have

continued to increase in both numbers and range.”).

In short, the record supports the Service’s conclusion that

disease- and human-caused mortality have not materially

threatened the expansion of the gray wolf population in the

Western Great Lakes region, and thus the Service reasonably

concluded that those factors do not counsel against delisting.

See Rossello ex rel. Rossello v. Astrue, 529 F.3d 1181, 1185

(D.C. Cir. 2008) (“Substantial-evidence review is highly

deferential to the agency fact-finder, requiring only ‘such

relevant evidence as a reasonable mind might accept as

adequate to support a conclusion.’”) (quoting Pierce v.

Underwood, 487 U.S. 552, 565 (1988)).

The Service further noted that state plans in Minnesota,

Michigan, and Wisconsin would monitor wolf disease and

mortality, providing an important backstop should new threats

emerge. See 2011 Rule, 76 Fed. Reg. at 81,697. The veterinary

pathologist peer reviewer agreed that the state plans would

adequately monitor and protect against new disease threats.

Finally, the data evidenced that mortality rates due to disease

and depredation would not be affected in any significant

measure by delisting. Id. at 81,700–81,701.

The Service’s analysis also answers the Humane Society’s

concern about the combined impact of disease and human-

caused mortality. The simple reality is that both disease- and

human-caused deaths have been simultaneously afflicting the

wolves, and yet the population has continued to grow

nonetheless.

B

The district court also held that the 2011 Rule is arbitrary

and capricious because the Service failed to adequately address

44

what it described as an “unregulated killing zone” in Minnesota

and the lack of state regulatory plans to monitor and protect the

wolves in six of the Western Great Lakes States. Humane

Society, 76 F. Supp. 3d at 134–136. We again conclude that

the Service’s decision was reasonable and grounded in

substantial evidence.

1

With respect to the Minnesota state plan, what the district

court labeled an “unregulated killing zone” refers to

depredation controls in one particular area of the State. The

Minnesota Plan divides the State into two zones. Within Zone

A, an area covering Northeastern Minnesota and the core of the

wolves’ territory, wolves can only be legally killed in defense

of a human life, in situations of “immediate threat” to the life

of a guard animal or domestic pet, or immediately after a

verified loss of livestock, domestic animals, or pets. See MINN.

STAT. § 97B.645, subdivs. 3, 5, 6. An “immediate threat” is

defined as a wolf stalking, attacking, or killing. See id.

§ 97B.645, subdiv. 12(c). Within this zone, a “control area”

can be opened immediately following the government’s

verification of the loss of livestock, domestic animals, or pets.

See id. § 97B.671, subdiv. 4(c). However, the control area can

only be opened for sixty days, and it must be within a one-mile

radius of the site of the loss. See id. § 97B.671, subdiv. 4(c),

(d). Trained and certified predator controllers will be paid

$150 for each wolf they kill within the control area. In

addition, owners of livestock and domesticated animals within

Zone A may shoot or destroy a wolf that poses “an immediate

threat” to such animals “on property owned, leased or occupied

by the owner” of the animal. Id. § 97B.645, subdiv. 5.

Likewise, in Zone B, a controlled killing area can be

opened following a verified loss of livestock, domestic

45

animals, or pets. See MINN. STAT. § 97B.671, subdiv. 4(b).

The control area may be opened for 30 to 214 days, depending

on the time of year, and may be opened anytime within five

years of a verified loss. See id.; J.A. 439. Only trained and

certified predator controllers, operating with the permission of

the landowners within the control area, may legally take a wolf.

See MINN. STAT. § 97B.671, subdivs. 1, 4(b). In addition, a

person may shoot a wolf on land owned, leased, or managed by

that person at any time to protect that person’s livestock,

domestic animals, or pets, regardless of whether the wolf is an

immediate threat. See id. § 97B.645, subdiv. 8.

Given those limitations, we disagree with the district

court’s and the Humane Society’s characterization of Zone B

as an “unregulated killing zone.” See Humane Society, 76 F.

Supp. 3d at 134; Humane Society’s Br. 77–78. Minnesota only

permits the killing of a wolf in Zone B by a limited class of

persons, and only after there has been some threat to livestock

or domestic animals. And at the time the 2011 Rule issued,

killing a wolf outside of the plan’s specific authorizations or

without a license was a gross misdemeanor. See MINN. STAT.

§ 97A.331, subdiv. 7 (2011), repealed by Act of May 3, 2012,

ch. 277, art. 1, § 91, 2012 Minn. Laws 1169.

In other words, the Minnesota Plan does not authorize the

unregulated killing of any wolf at any time by any person. It

provides for regulated killing. To be sure, killings are allowed

at higher numbers than the Humane Society wants. That does

not make the Service’s decision unreasoned or arbitrary and

capricious, however. To the contrary, the Service adequately

explained why Minnesota’s new depredation scheme was

unlikely to threaten the wolves’ survival. In coming to that

conclusion, the Service did not ignore that the wolves residing

in Zone B “could be subject to substantial reduction in

numbers, and at the extreme, wolves could be eliminated from

46

Zone B.” 2011 Rule, 76 Fed. Reg. at 81,704. Rather, the

Service explained that “there is no way to reasonably evaluate

in advance the extent to which residents of Zone B will use this

new authority, nor how vulnerable Zone B wolves will be” in

actuality. Id. What the Service did know and found relevant

to its decision was that statistical data from 2007 to 2008, when

the Minnesota gray wolves were not federally listed, revealed

that only six wolves were shot in Zone B during that time

period, and in 2009 only one additional wolf was taken. Id.

Overall, the total number of wolves taken through depredation

controls from 2007 to 2008 (133 in 2007, 143 in 2008) was

comparable to the number that had been taken under a prior

federal regulation. See id. (under pre-2007 federal regulation,

105 wolves were killed in 2004, 134 in 2005, and 122 in 2006).

Looking to data from 2007 to 2008 to predict the

consequences of delisting was entirely reasonable because

there was an absence of federal regulation and a presence of

state depredation authorizations nearly identical to the regime

that would operate after delisting. In addition, the Service is

obligated to continue monitoring the gray wolf for five years

following any successful delisting and to make “prompt use”

of its emergency powers “to prevent a significant risk to the

well being of any such recovered species.” 16 U.S.C.

§ 1533(g)(2). Concerned entities also remain free to petition

the Service to relist the gray wolf should it be threatened once

more. Id. § 1533(b)(3). For those reasons, the Service’s

consideration of the Minnesota plan in its delisting decision

was not arbitrary or capricious and was reasonably grounded in

substantial evidence.

2

The Service’s decision to delist notwithstanding the lack

of state plans in North and South Dakota, Illinois, Iowa, Ohio,

47

and Indiana also did not rise to the level of arbitrary-and-

capricious decisionmaking, given the near non-existence of

gray wolves within those jurisdictions. The boundaries of the

Western Great Lakes segment includes only portions, at times

very small ones, of those six States, and few if any gray wolves

are found there. See, e.g., 2011 Rule, 76 Fed. Reg. at 81,671

(map of Great Lakes segment area); id. at 81,700 (sixteen total

reports of wolf sightings or deaths in North Dakota from 1999

to 2003); id. at 81,713 (no gray wolves found in Ohio and

Indiana). Scientific literature cited by the Service indicates that

the only gray wolves found in North and South Dakota are

primarily loners, not packs or mates with pups. Id. at 81,679;

see also id. at 81,700 (detailing every report of wolves in North

and South Dakota). Since 1993, there have been only five

verified wolf deaths from depredation and eight total deaths

from all causes of mortality in North and South Dakota. Id. at

81,713 (depredation deaths); id. at 81,700 (total deaths). Both

Ohio and Indiana list the gray wolf as “extirpated” from their

States. Id. at 81,713. Indiana, Illinois, Ohio, and Iowa, “do not

contain suitable habitat [for gray wolves] or currently

established packs[.]” Id.

In addition, the absence of formal state wolf plans does not

mean that the few wolves in those States lack legal protection.

The Service explained that, in North Dakota and Iowa, there is

no open season on wolves because they are “furbearers.” 2011

Rule, 76 Fed. Reg. at 81,713. Illinois includes gray wolves on

its state endangered species list, making it illegal to possess or

kill a wolf in the state. Id.; see 520 ILL. COMP. STAT. 10/3

(detailing state law protections for endangered species). In

South Dakota, wolves are not listed as a game animal open for

hunting. 2011 Rule, 76 Fed. Reg. at 81,713. In short, in North

Dakota, South Dakota, Iowa, and Illinois, gray wolves are

protected from indiscriminate hunting. Only in Indiana and

Ohio, where wolves no longer exist, are there no formal

48

protections in place. Id. But it is not arbitrary or capricious to

overlook a State’s failure to protect an animal that does not

exist within its borders.

Further, for all six of the States with no wolf plans, the

Service reasonably concluded that the deaths of any wolves

that might enter those States would be so minimal as to pose no

threat to the segment’s survival. 2011 Rule, 76 Fed. Reg. at

81,713. For example, the deaths since 1993 of a total of eight

wolves in North and South Dakota is quite unlikely to pose a

survival threat to the several thousand wolves protected within

Minnesota’s borders. Similarly, the death of a lone wolf that

might roam into Indiana or Ohio would be highly unlikely to

affect the health or sustainability of the Western Great Lakes

segment.

The district court faulted the Service’s decision on the

ground that the limited number of wolves “does not foreclose

the possibility of an increased presence there[.]” Humane

Society, 76 F. Supp. 3d at 134. True. But the Endangered

Species Act tasks the Service with determining whether the

species is endangered or threatened, not whether the species

could reach still higher population levels if given more

protection. Challenges to expanding a species’ territory do not

by themselves undermine survival in existing territory.

We accordingly hold that the absence of conservation

plans for the gray wolves in North Dakota, South Dakota,

Illinois, Iowa, Ohio, and Indiana does not render the Service’s

decision to delist the Western Great Lakes gray wolves

arbitrary and capricious on this record.

C

Finally, the Humane Society challenges the 2011 Rule as

violating the Service’s statutory obligation to ground the

49

delisting decision in the best available science, 16 U.S.C.

§ 1533(b)(1)(A). The Humane Society argues first that science

does not support the 2011 Rule because the Service admits that

the Minnesota gray wolf is not a separate species of wolf under

the Endangered Species Act. The Humane Society argues

secondly that the 2011 Rule responded to political pressure, not

science. Neither argument succeeds.

1

With respect to the status of the gray wolf in Minnesota,

the Service initially proposed classifying it as a separate

species (the “eastern wolf” or Canis lycaon). See Proposed

Rule to Revise the List of Endangered and Threatened Wildlife

for the Gray Wolf (Canis lupus), 76 Fed. Reg. 26,086, 20,086

(May 5, 2011) (“Proposed 2011 Rule”). But in the final 2011

Rule, the Service admitted that “neither a scientific consensus

nor the majority opinion of researchers on the taxonomy of

wolves” supported designating the wolves in Minnesota as a

distinct species. 2011 Rule, 76 Fed. Reg. at 81,669. In the

Humane Society’s view, once the Service determined that the

Minnesota gray wolf was not a separate species, the Service

should have withdrawn the rule, rather than promulgate a final

rule “without knowing the species that it is both listing and

delisting.” Humane Society’s Br. 61 (emphasis in original).

But the Service did know that the Minnesota wolves that

it added to the Western Great Lakes segment were part of the

gray wolf species. See 2011 Rule, 76 Fed. Reg. at 81,669 (“The

wolves that occupy the [Western Great Lakes segment] have

long been accepted as gray wolves, C. lupus[.]”). In that

respect then, the Service’s treatment of the wolves in

Minnesota as part of the gray wolf species aligns with the best

science available, which was inconclusive as to whether the

Minnesota wolves were a separate species or just a subspecies

50

of the gray wolf. See id. at 81,668–81,669 (discussing the

scientific literature on wolf taxonomy).

In any event, the Service’s recognition of the Western

Great Lakes segment did not depend on a finding that the

Minnesota wolves were a separate species. From the outset,

the Service proposed recognizing a distinct population segment

in the region. See Proposed 2011 Rule, 76 Fed. Reg. at 26,094

(“Within this rule we are proposing changes to the listing for

C. lupus and are initiating a status review for C. lycaon. These

two actions combined will address all wolves in the [Western

Great Lakes] region.”); id. (“Our proposed action here is to

establish the existence of a [Western Great Lakes] distinct

population segment of C. lupus and to determine that the

[segment] is neither endangered nor threatened, despite its

proximity to a closely related species, C. lycaon—a species

whose status we will evaluate for possible protection under the

Act in the near future.”). When the science did not support

according a distinct species status to wolves in Minnesota, the

Service followed where the science led by treating the

Minnesota wolves as non-distinct and grouping them with all

of the other wolves in the Western Great Lakes region.

2

The record likewise does not support the Humane

Society’s charge that the delisting decision was driven by

politics rather than science. The Society’s argument relies

primarily on a single letter from United States Senator Amy

Klobuchar of Minnesota supporting delisting, which prompted

several emails within the Service discussing the Senator’s

letter. But a single communication from an elected

representative conveying the views of constituents could not by

itself politically poison an agency’s decisionmaking. That is

especially true when, as here, the Society does not point to any

51

science that the Service ignored, misused, or manipulated, or

to any material switch in the Service’s position after receiving

the letter.

On December 7, 2010, Senator Klobuchar sent a letter to

Ken Salazar, the then-Secretary of the Interior, “urg[ing]” the

Service “to expedite the delisting of the gray wolf in the Great

Lakes” and communicating her intent to introduce legislation

“to help speed-up this process.” J.A. 771. Assistant Secretary

Thomas Strickland’s response to Senator Klobuchar referenced

the 2009 Rule delisting the gray wolf in that region, which at

that time had been withdrawn due to litigation, and further

informed the Senator that the Service intended to publish a new

proposed rule delisting the wolf by April 2011. Senator

Klobuchar then made a public announcement about the

Service’s forthcoming proposed rule.

Such a commonplace senatorial inquiry, standing alone,

cannot taint an agency decision that is otherwise adequately

reasoned and grounded in the factual record. And certainly not

here where the Service’s threefold effort to delist the region’s

gray wolves preceded the Senator’s letter by multiple years.

See 2003 Rule, 68 Fed. Reg. at 15,857 (final rule delisting gray

wolves); 2007 Rule, 72 Fed. Reg. at 6,101 (same); 2009 Rule,

74 Fed. Reg. at 15,120 (same). In addition, the Service had

received multiple petitions to delist the Western Great Lakes

wolves and had decided that those petitions presented

substantial evidence meriting delisting several months before

Senator Klobuchar’s letter. See 90-Day Finding on Petitions to

Delist the Gray Wolf in Minnesota, Wisconsin, Michigan and

the Western Great Lakes, 75 Fed. Reg. 55,730, 55,735 (Sept.

14, 2010).

The Humane Society’s reliance on Save Our Springs v.

Babbitt, 27 F. Supp. 2d 739 (W.D. Tex. 1997), actually proves

52

the opposite. Unlike the case at hand, the Service in Save Our

Springs succumbed to political pressure and withdrew a

proposed listing of salamanders even though it had earlier

stated that the salamander was the “top priority in the region

for listing.” Id. at 745. The level of political pressure,

moreover, bears no resemblance to the single letter in this case.

In Save Our Springs, the pressure came through a letter from

the Governor of Texas, emails from employees worrying that

listing was a “hot” issue and noting “intense opposition” to the

proposal from all levels of Texas government, and “inferences

that political lobbyists for the development community worked

with political appointees.” Id. The record here reflects no such

concerted pressure, no manipulation or disregard of material

evidence, and no change in the Service’s course of action

before and after the single communication. 10

We accordingly find no merit to the charge of improper

political influence in this case.

V

A common remedy when we find a rule is invalid is to

vacate. See Sugar Cane Growers Co-op. of Fla. v. Veneman,

289 F.3d 89, 97 (D.C. Cir. 2002) (“Normally when an Agency

* * * clearly violates the APA we would vacate its action[.]”).

But we may remand without vacatur depending upon “the

seriousness of the order’s deficiencies (and thus the extent of

10

Likewise, Western Watersheds Project v. Fish & Wildlife

Service, 535 F. Supp. 2d 1173 (D. Idaho 2007), involved a “well-

documented history” of a Deputy Assistant Secretary “intervening in

the listing process,” “editing scientific conclusions” and

“intimidating [Service] staffers,” id. at 1175; see also id. at 1188

(The Deputy Assistant Secretary “had extensive involvement in the

sage-grouse listing decision, used her intimidation tactics in this

case, and altered the ‘best science’ to fit a not-warranted decision.”).

53

doubt whether the agency chose correctly) and the disruptive

consequences of [vacating the Rule,] an interim change that

may itself be changed.” Id. at 98 (citation omitted); Allina

Health Servs. v. Sebelius, 746 F.3d 1102, 1110 (D.C. Cir.

2014); see also United States Sugar Corp. v. EPA, 844 F.3d

268, 270 (D.C. Cir. 2016) (per curiam) (“Although remand

without vacatur may in some circumstances invite prejudicial

agency delay, in other circumstances vacatur itself carries

more-harmful consequences. We have therefore frequently

remanded without vacating when a rule’s defects are curable

and where vacatur would at least temporarily defeat * * * the

enhanced protection of the [rule].”) (first alteration in original;

internal quotation marks and citations omitted).

In this case, the agency’s analysis (i) wholly failed to

address the effect on the remnant population of carving out the

Western Great Lakes segment, and in doing so (ii) misapplied

the Service’s own discreteness and significance tests, and also

(iii) turned its back on the implications of historical range loss.

Those are major shortcomings that go to the heart of the

Service’s delisting decision. Given the serious and pervading

role those deficiencies played in the agency’s decisionmaking,

there is substantial “doubt whether the [Service] chose

correctly” in promulgating the 2011 Rule, Sugar Cane

Growers, 289 F.3d at 98 (citation omitted). That makes vacatur

appropriate. See id. at 97–98; Fox Television Stations, Inc. v.

FCC, 280 F.3d 1027, 1049, 1052–1053 (D.C. Cir. 2002).

In addition, vacatur would not trigger disruptive

consequences. The agency has failed repeatedly over the last

sixteen years to make a delisting decision that complies with

the APA, and it has not shown that vacatur here would be any

more disruptive than it was on the Service’s last three failed

occasions. With respect to protecting domestic animals in the

interim, federal regulations already permit depredation control

54

in Minnesota, which is where most of the gray wolves in the

Western Great Lakes segment live. See 50 C.F.R. § 17.40(d).

Because of the “seriousness of the [Rule’s] deficiencies”

and the absence of materially “disruptive consequences,” we

affirm the judgment of the district court vacating the Service’s

2011 Rule.

So ordered.