FILED
                                                                   United States Court of Appeals
                                     PUBLISH                               Tenth Circuit

                     UNITED STATES COURT OF APPEALS                      March 17, 2020

                                                                      Christopher M. Wolpert
                           FOR THE TENTH CIRCUIT                          Clerk of Court
                       _________________________________

NEW MEXICO FARM AND
LIVESTOCK BUREAU; NEW MEXICO
CATTLEGROWERS’ ASSOCIATION;
NEW MEXICO FEDERAL LANDS
COUNCIL,

      Plaintiffs - Appellants,
                                                          No. 17-2211
v.

UNITED STATES DEPARTMENT OF
INTERIOR; RYAN ZINKE, in his official
capacity as Secretary of the United States
Department of Interior; UNITED STATES
FISH AND WILDLIFE SERVICE;
DANIEL M. ASHE, in his official capacity
as Director of the United States Fish and
Wildlife Service,

      Defendants - Appellees,

and

CENTER FOR BIOLOGICAL
DIVERSITY; DEFENDERS OF
WILDLIFE,

      Intervenor Defendants - Appellees.
                      _________________________________

                    Appeal from the United States District Court
                          for the District of New Mexico
                        (D.C. No. 2:15-CV-00428-KG-CG)
                      _________________________________
Christina M. Martin, Pacific Legal Foundation, Palm Beach Gardens, Florida (Anthony
L. François, Pacific Legal Foundation, Sacramento, California, with her on the briefs), for
Plaintiffs-Appellants.

Mark R. Haag, Environment and Natural Resources Division, U.S. Department of Justice,
Washington, D.C. (Jeffrey Bossert Clark, Assistant Attorney General, Eric Grant, Deputy
Assistant Attorney General, Joan M. Pepin, and Nicole M. Smith, Attorneys,
Environment and Natural Resources Division, U.S. Department of Justice, Washington,
D.C.; Frank Lupo, Of Counsel, Office of the Solicitor, Southwest Region, U.S.
Department of the Interior, Albuquerque, New Mexico, with him on the brief), for
Defendants-Appellees.

John Buse, Center for Biological Diversity, Oakland, California, and McCrystie Adams,
Defenders of Wildlife, Denver, Colorado, filed a brief for Intervenors-Appellees.

                        _________________________________

Before LUCERO, HARTZ, and MATHESON, Circuit Judges.
                  _________________________________

LUCERO, Circuit Judge.
                    _________________________________


       This case involves the designation by the U.S. Fish and Wildlife Service (“the

Service”) of critical habitat for the jaguar, pursuant to the Endangered Species Act

(“ESA”). Plaintiffs filed suit, contending the Service’s designation was arbitrary and

capricious. The district court ruled in favor of the Service. Exercising jurisdiction under

28 U.S.C. § 1291, we reverse and remand to the district court.

                                             I

       The jaguar (Panthera onca) is a large felid found in the southwestern United

States, Mexico, Central America, and South America. See Endangered and

Threatened Wildlife and Plants; Designation of Critical Habitat for Jaguar, 79 Fed.

Reg. 12,572, 12,573 (Mar. 5, 2014) (hereinafter “Final Critical Habitat

                                             2
Designation”). The Service listed the jaguar as a foreign endangered species in 1972

under the Endangered Species Conservation Act (“ESCA”), a precursor to the ESA.

List of Endangered Foreign Fish and Wildlife, 37 Fed. Reg. 6476 (Mar. 30, 1972)

(hereinafter “Foreign Jaguar Listing”). After the ESA took effect in 1973, the

Service relisted as endangered foreign jaguar populations, but did not include

domestic ones. In a 1980 proposed rulemaking, the Service acknowledged this

“inadvertent oversight,” stated it had been the Service’s intention to list all jaguar

populations as endangered, and proposed adding domestic jaguar populations to the

list. Endangered and Threatened Wildlife and Plants, Proposed Endangered Status

for U.S. Populations of Five Species, 45 Fed. Reg. 49,844, 49,844 (July 25, 1980)

(hereinafter “1980 Proposed Rule”). Ultimately, the agency listed both foreign and

domestic jaguar populations as endangered in 1997. Endangered and Threatened

Wildlife and Plants; Final Rule to Extend Endangered Status for the Jaguar in the

United States, 62 Fed. Reg. 39,147 (July 22, 1997) (hereinafter “Final Jaguar

Listing”).

      In 2014, the Service published a final rule designating 764,207 acres in New

Mexico and Arizona as critical jaguar habitat. Final Critical Habitat Designation, 79

Fed. Reg. at 12,572. The area was divided into six units. 

and 6 are the

subject of this litigation. Unit 5, the Peloncillo Unit, covers 102,724 acres in the

Peloncillo Mountains in Cochise County, Arizona, and Hidalgo County, New

Mexico. 

the San Luis Unit, covers 7714 acres in the San Luis Mountains

in Hidalgo County, New Mexico. 

whether Units 5 and 6 were

                                            3
occupied by jaguars at the time they were listed, the Service used data on undisputed

Class I jaguar sightings1 between 1962 and 2013.2 There were Class I jaguar

sightings in the Units in 1995, 1996, and 2006, but no Class I sightings there between

1962 and the 1990s. 

Nonetheless, the Service found Units 5 and 6

“may have been occupied” by jaguars in 1972 because “[j]aguars were rare on the

landscape and distributed over large, rugged areas,” “jaguars are cryptic and

nocturnal by nature,” and “no survey effort was made to detect them in 1972.” 

      Based on this finding, the agency categorized Units 5 and 6 as “[o]ccupied at

time of listing.” 

It found the Units satisfied the ESA’s requirements

for occupied critical habitat but noted there was substantial uncertainty in the finding




      1
        Jaguar sighting reports are sorted into “classes” based on the degree of
certainty that a jaguar was sighted; the Service considers only undisputed Class I
reports as valid records of jaguar sightings in its critical habitat designation. 

The Service notes several disputed Class I records, 

but
these are not relevant to our analysis because they did not occur in Units 5 and 6.
      2
         Based on a finding that the average jaguar lifespan is ten years, the agency
stated that jaguar sightings between 1962 and 1982—from ten years before to ten
years after the 1972 listing date—could indicate the presence of jaguars in 1972. 

The Service also concluded that Class I sightings from 1982 to 2013 were
relevant evidence of jaguar occupancy in 1972. 

Final Critical Habitat Designation alternately stated that Units 5 and 6
were occupied at the time of listing and that they may have been occupied at that
time. For example, in a table describing all the units, Units 5 and 6 are in a column
labeled “Occupied at time of listing,” but a description of the table states the column
includes units that “may have been occupied at the time of listing.” 

                                           4
that the Units were occupied. 

Accordingly, it alternatively determined

that the Units qualified as unoccupied critical habitat under the ESA. 

      Plaintiffs filed suit, challenging the designation of Units 5 and 6 as arbitrary

and capricious. The district court concluded that although it owes deference to the

Service on matters of scientific expertise, the evidence was insufficient to support a

finding that jaguars occupied the Units in 1972. Nevertheless, because the Service

alternatively determined that the Units could be designated as unoccupied critical

habitat under the ESA, the court held the designation of the Units as critical habitat

was not arbitrary and capricious. Plaintiffs timely appealed.

                                            II

      Our review of the Service’s actions under the ESA is governed by the

Administrative Procedure Act, and we review the district court’s decision de novo.

See N.M. Cattle Growers Ass’n v. U.S. Fish & Wildlife Serv., 

, 1281

(10th Cir. 2001). “We cannot set aside an agency decision unless it fails to meet

statutory, procedural or constitutional requirements, or unless it is arbitrary,

capricious, an abuse of discretion, or otherwise not in accordance with law.” 

      The ESA sets forth a procedure by which the Service designates critical habitat

for endangered species. 16 U.S.C. § 1533. It must do so “on the basis of the best

scientific data available and after taking into consideration the economic impact, the

impact on national security, and any other relevant impact, of specifying any



                                            5
particular area as critical habitat.” § 1533(b)(2). The ESA defines “critical habitat

for a threatened or endangered species” as:

      (i) the specific areas within the geographical area occupied by the
      species, at the time it is listed in accordance with the provisions of
      section 1533 of this title, on which are found those physical or
      biological features (I) essential to the conservation of the species and
      (II) which may require special management considerations or
      protection; and

      (ii) specific areas outside the geographical area occupied by the species
      at the time it is listed in accordance with the provisions of section 1533
      of this title, upon a determination by the Secretary that such areas are
      essential for the conservation of the species.

§ 1532(5)(A).

                                           A

      As a threshold matter, we address the time at which the jaguar was “listed in

accordance with the provisions of section 1533.” 

Critical Habitat

Designation stated:

      While the jaguar was not explicitly listed in the United States until
      July 22, 1997, we are using the date the jaguar was listed throughout its
      range as endangered in accordance with the Endangered Species
      Conservation Act, which is March 30, 1972. Our rationale for using
      this date is based on our July 25, 1979, publication in which we asserted
      that it was always the intent of the Service that all populations of seven
      species, including the jaguar, deserved to be listed as endangered,
      whether they occurred in the United States or in foreign countries.
      Therefore, our intention was to consider the jaguar endangered
      throughout its entire range when it was listed as endangered in 1972,
      rather than only outside of the United States.

79 Fed. Reg. at 12,581 (citations omitted). Intervenors argue that the Service was

required to use 1997, the date of the Final Jaguar Listing, instead.



                                           6
      The ESA expressly requires the agency to consider occupancy at the time a

species “is listed,” §§ 1532(5)(A)(i), (ii) (emphasis added), not at the time the

Service intended to list it or to consider it endangered. Accordingly, we reject the

Service’s explanation that it was “always the intent of the Service . . . to consider the

jaguar endangered throughout its entire range,” Final Critical Habitat Designation,

79 Fed. Reg. at 12,581. To determine whether the agency was required to use the

1997 listing, we look to the complex regulatory history of the jaguar’s listing as an

endangered species.

      Under the Endangered Species Preservation Act of 1966 (“ESPA”), the

Secretary of the Interior maintained a list of “native fish and wildlife” that were

“threatened with extinction.” Pub. L. No. 89-669, § 1(c), 80 Stat. 926, 926 (1966),

repealed by ESA, Pub. L. No. 93-205, § 14, 87 Stat. 884, 903 (1973). The ESPA

required the Secretary to “consult[] with the affected States” before designating

native species as threatened with extinction. 

Congress passed the ESCA. That statute required the Secretary to

designate “species or subspecies of fish or wildlife” that are “threatened with

worldwide extinction.” Pub. L. No. 91-135, § 3(a), 83 Stat. 275, 275 (1969),

repealed by ESA, § 14, 87 Stat. at 903. Pursuant to the ESCA, the Service

maintained a “U.S. List of Endangered Foreign Fish and Wildlife” at 50 C.F.R.,

app. A. It added the jaguar to this list of foreign endangered species in 1972.

Foreign Jaguar Listing, 37 Fed. Reg. at 6476. Because the ESCA did not repeal the



                                            7
ESPA, the ESPA’s requirement for the Service to maintain a list of “native fish and

wildlife” remained in effect.

       In 1973, Congress passed the ESA, which repealed both the ESPA and the

ESCA. ESA, § 14, 87 Stat. at 903. The ESA requires the Secretary to maintain “a

list of all species determined . . . to be endangered species and a list of all species

determined . . . to be threatened species.” 

87 Stat. at 887 (codified at

§ 1533(c)(1)). It eliminated the requirement for maintaining separate lists of native

species under the ESPA and foreign species under the ESCA. As enacted, the ESA

further provided:

       [A]ny list in effect on the day before the date of the enactment of [the
       ESA] of species of fish or wildlife determined by the Secretary of the
       Interior, pursuant to the [ESCA], to be threatened with extinction shall
       be republished to conform to the classification for endangered species or
       threatened species, as the case may be, provided for in this Act, but until
       such republication, any such species so listed shall be deemed an
       endangered species within the meaning of this act. The republication of
       any species pursuant to this paragraph shall not require public hearing
       or comment . . . .

87 Stat. at 888 (codified at § 1533(c)(3)) (repealed 1982).

       In accordance with this provision, the Service promulgated a list of

endangered and threatened species in 1975, consolidating the formerly separate lists

of native and foreign species. Reclassification of the American Alligator and Other

Amendments, 40 Fed. Reg. 44,412 (Sept. 26, 1975) (hereinafter “Consolidated

Listing”). The agency confirmed that the ESA list “br[ought] together in one place

all of the endangered and threatened species” previously listed. 

The

Consolidated Listing included the jaguar (Panthera onca) and stated its “Known

                                             8
Distribution” is “Central and South America.” 

It also included the

original listing date of the species under the ESCA.5

      In 1979, the Service issued a notice stating that because the jaguar and other

species had been listed only as foreign, not native, endangered species under the pre-

ESA framework, their domestic populations were “not currently listed” under the

ESA. Notification that the populations of seven endangered species are not currently

protected by the [ESA], 44 Fed. Reg. 43,705, 43,705 (July 25, 1979).6 The agency

acknowledged this “inadvertent” failure again the following year; it stated it had


      4
        We observe that in the 1978 republication of the endangered species list, the
Service amended the Known Distribution to read, “U.S. (Southwestern) to South
America.” Republication of the List of Species, 43 Fed. Reg. 58,030, 58,033
(Dec. 11, 1978). In 1980, this was again amended to read, “U.S.A. (TX, NM, AZ),
Central and South America.” Republication of the Lists of Endangered and
Threatened Species and Correction of Technical Errors in Final Rules, 45 Fed. Reg.
33,768, 33,770 (May 20, 1980) (hereinafter “1980 Republication”).
      5
         In the column for “When Listed,” the Consolidated Listing erroneously stated
the jaguar was listed in a 1970 rulemaking, List of Endangered Foreign Fish and
Wildlife, 35 Fed. Reg. 18,319 (Dec. 2, 1970). Consolidated Listing, 40 Fed. Reg.
at 44,418. This appears to be a clerical error; it should have referred to the 1972
Foreign Jaguar Listing. The entries for most of the other species listed along with the
jaguar in 1972—the cheetah, leopard, tiger, snow leopard, ocelot, and margay—
correctly referred to the 1972 listing. 

The entry for the tiger cat,
like the entry for the jaguar, erroneously referred to the 1970 listing. 

      This error was corrected between the 1979 and 1980 republications of the
endangered species list. Compare Republication of List of Species, 44 Fed. Reg.
3636, 3639 (Jan. 17, 1979) with 1980 Republication, 45 Fed. Reg. at 33,770.
      6
        This notice stated that the Service had not consulted with the governors of
any state, as required under the pre-ESA framework. 

stated it
“intend[ed] to take action as quickly as possible to propose the U.S. populations of
these species for listing.” 

to list all jaguar populations as endangered under the ESA and proposed

amending the list of endangered species to state that the jaguar’s “Historic Range”

was “Texas, New Mexico, Arizona, South through Central America to South

America.” 1980 Proposed Rule, 45 Fed. Reg. at 49,844, 49,847.7 The 1980 Proposed

Rule was withdrawn in 1982. Endangered and Threatened Wildlife and Plants:

Notice of Withdrawal of an Expired Proposal for Listing of the U.S. Populations of

the Thick-Billed Parrot, Short-Tailed Albatross, Margay Cat, and Jaguar, 47 Fed.

Reg. 41,145, 41,145 (Sept. 17, 1982).

      Twelve years later, in 1994, the agency again proposed listing domestic jaguar

populations as endangered. Endangered and Threatened Wildlife and Plants;

Proposed Endangered Status for the Jaguar In the United States, 59 Fed. Reg. 35,674

(July 13, 1994). In 1997, it issued a final rulemaking listing foreign and domestic

jaguar populations as endangered. Final Jaguar Listing, 62 Fed. Reg. at 39,147.

                                           B

      In light of this complex regulatory history, we address whether the jaguar was

“listed in accordance with the provisions of section 1533” in 1972 or 1997.

§§ 1532(5)(A)(i), (ii). The statute does not directly address which time of listing the

Service must consider in a case such as this one, in which a species’ foreign and




      7
       The list of endangered species already in effect at the time of the 1980
Proposed Rule stated that the jaguar’s “Known Distribution” was “U.S.A. (TX, NM,
AZ), Central and South America.” 1980 Republication, 45 Fed. Reg. at 33,770.
                                          10
domestic populations were listed on different dates under different statutory schemes.

To resolve this issue, we must first determine the meaning of the term “species.”

       The ESA offers little guidance on this issue. It does not actually define the

term “species”; rather, it merely states that the term “includes any subspecies of fish

or wildlife or plants, and any distinct population segment of any species of vertebrate

fish or wildlife which interbreeds when mature.” § 1532(16) (emphasis added).8

       We therefore look to the ordinary meaning of the word “species.” “[A]bsent

evidence to the contrary, the ordinary meaning of the words used [in a statute]

expresses legislative intent. When Congress has used technical words or terms of art,

the term must be given its technical or scientific meaning.” United States v. Easter,

, 1558 (10th Cir. 1992) (citations omitted). A “species” is defined as:

       a category of biological classification ranking immediately below the
       genus or subgenus, comprising related organisms or populations
       potentially capable of interbreeding, and being designated by a binomial
       that consists of the name of a genus followed by a Latin or latinized
       uncapitalized noun or adjective agreeing grammatically with the genus
       name.

Species, Merriam-Webster Dict., http://www.merriam-webster.com/dictionary/

species (last visited Mar. 3, 2020).

       The binomial designation of the jaguar is Panthera onca. See 50 C.F.R.

§ 17.11(h). Panthera is the genus, onca the species. The foreign and domestic

populations of the jaguar belong to the same Panthera onca species. There is no



       8
         In contrast, almost all the other provisions in the definitions section of the
statute state what a particular term “means.” See generally § 1532.
                                            11
indication in the record that these populations would be incapable of interbreeding.

To the contrary, the Final Critical Habitat Designation stated that the only breeding

populations of jaguars are foreign populations. The domestic population is therefore

comprised of individual jaguars dispersing from the nearest breeding population,

which is in Mexico. See 79 Fed. Reg. at 12,589.

        We acknowledge that the 1980 Proposed Rule and the 1997 Final Jaguar

Listing state that domestic jaguars were not subject to the ESA’s protections. 45 Fed.

Reg. at 49,844; 47 Fed. Reg. at 41,145. But the question before us is what year the

jaguar—Panthera onca—was listed as endangered for purposes of §§ 1532(5)(A)(i),

(ii).

        We conclude that year was 1972. The foreign and domestic jaguar populations

listed by the Service comprise one species under the ESA. That species was listed as

a foreign endangered species under the ESCA in 1972. When the ESA was enacted

in 1973, § 1533 provided that the ESCA list would be republished. ESA, § 4(c)(3),

87 Stat. at 888 (repealed 1982). The entry for the jaguar species in the republished

list referred to the original listing date of the jaguar species under the ESCA.

Consolidated Listing, 40 Fed. Reg. at 44,418. Additionally, the 1978 and 1980

republications list domestic ranges for the jaguar. See Republication of the List of

Species, 43 Fed. Reg. at 58,033; 1980 Republication, 45 Fed. Reg. at 33,770. The

current listing of endangered species includes both the Foreign Jaguar Listing and the

Final Jaguar Listing under “Listing citations and applicable rules.” 50 C.F.R.

§ 17.11(h).

                                           12
      Our conclusion aligns with the Final Critical Habitat Designation’s finding

that “the jaguar was listed throughout its range as endangered” in 1972. 79 Fed. Reg.

at 12,581. It is also consistent with the legislative history of § 1532(5)(A). The ESA

did not originally include a definition of “critical habitat.” 87 Stat. 884. That

definition was added in a 1978 amendment. ESA Amendments of 1978, Pub. L. No.

95-632, § 2, 92 Stat. 3751, 3751 (1978). The proponent of the amendment stated that

a critical habitat designation “must be made at the time [a species is] placed on the

list.” 124 Cong. Rec. S11,042 (daily ed. July 18, 1978) (statement of Sen. McClure).

He explained the definition was a response to the prospect of human displacement if

an endangered species were to expand out of the area it occupied at the time of

listing, offering the example of the grizzly bear’s expansion out of Yellowstone

National Park. 

      Thus, Congress intended to ensure that even if the range of a species expands,

the Service designates critical habitat under § 1532(5)(A)(i) only for areas occupied

at the initial time of listing. For areas unoccupied at the time of listing into which a

species has expanded, the Service designates critical habitat under the more stringent


      9
        The definition of critical habitat appears to be modeled on language proposed
by a representative of the National Forest Products Association, who also expressed
concerns about the consequences of the expansion of the grizzly bear’s range.
Endangered Species Oversight: Hearing Before the S. Comm. on Fisheries and
Wildlife Conservation and the Env’t, 95th Cong. 726, 728 (1978) (statement of
William Haselton, representing Nat’l Forest Prods. Ass’n). The timber industry
representative’s proposed definition of unoccupied critical habitat referred to areas
“essential to the continued existence of the species,” 

enacted version
of § 1532(5)(A)(ii) discusses areas “essential for the conservation of the species.”

                                           13
criteria in § 1532(5)(A)(ii). Our holding that the Service must use the initial listing

date, not a later listing date after the jaguar’s range has expanded, is consistent with

this intent.

                                             C

       Having concluded that the jaguar was initially listed as endangered in 1972,

we turn to whether Units 5 and 6 were occupied by jaguars at that time.10 We must

determine whether the Service’s finding that the jaguar occupied Units 5 and 6 in

1972 was supported by “substantial evidence in the administrative record,” meaning

“such relevant evidence as a reasonable mind might accept as adequate to support a

conclusion.” Colo. Wild, Heartwood v. U.S. Forest Serv., 

, 1213 (10th

Cir. 2006) (quotations omitted).

       The ESA and its implementing regulations do not define “occupancy,” and the

Tenth Circuit has not directly addressed how the term is defined. Plaintiffs contend

that “occupy” is synonymous with “reside.” We disagree. A species “occupies” an

area if it “uses [the area] with sufficient regularity that it is likely to be present during

any reasonable span of time.” Ariz. Cattle Growers’ Ass’n v. Salazar, 

, 1165 (9th Cir. 2010). “Determining whether a species uses an area with


       10
         Plaintiffs appear to contend the Service forfeited the argument that jaguars
occupied Units 5 and 6. Because the district court ultimately entered judgment in the
Service’s favor, it could not appeal this issue. See United States v. Am. Ry. Exp.
Co., 

, 435 (1924) (holding a party cannot appeal from a favorable
judgment). This argument is therefore not forfeited. Further, we may affirm the
“lower court’s ruling on any grounds adequately supported by the record, even
grounds not relied upon by the district court.” United States v. Mabry, 

, 1165 n.1 (10th Cir. 2013).
                                             14
sufficient regularity that it is ‘occupied’ is a highly contextual and fact-dependent

inquiry.” 

      We turn to the Service’s factual findings regarding whether jaguars used

Units 5 and 6 with sufficient regularity for the Units to be considered occupied in

1972. Because the average jaguar lifespan is ten years, the agency stated that jaguar

sightings between 1962 and 1982—from ten years before to ten years after the 1972

listing date—could indicate the presence of jaguars in 1972. Final Critical Habitat

Designation, 79 Fed. Reg. at 12,581. There were no Class I jaguar sightings in the

units between 1962 and 1982, however, and no other evidence of jaguar presence

during that time period. 

also concluded that Class I sightings from 1982 to 2013 are

relevant evidence of presence in 1972 because it is “likely those areas were occupied

at the time of the original listing, but jaguars had not been detected because of their

rarity, the difficulty in detecting them, and a lack of surveys for the species.” 

It lists three jaguar sightings in Units 5 and 6: a jaguar track in Unit 5 in

1995, a photograph of a jaguar in Unit 5 in 1996, and a photograph of a jaguar in

Unit 6 in 2006. 

The Service observed that “[j]aguars are difficult

to detect due to their rarity, cryptic appearance, elusive behavior, and habitat

complexity.” 

Further, there were no concerted efforts to detect jaguars

before 1997, when the Borderlands Jaguar Detection Project set up remote camera

stations and conducted track and scat surveys. 

inadequacy of the

available data regarding jaguar occupancy, the agency found that these three

                                           15
sightings provided sufficient evidence Units 5 and 6 “may have been occupied by

jaguars” in 1972. 

It therefore concluded that Units 5 and 6 satisfied

the requirements for occupied critical habitat under § 1532(5)(A)(i).

       On appeal, the agency argues that we must affirm its finding that Units 5 and 6

were occupied in 1972 because we must defer to its scientific expertise. Though we

are mindful that the agency need only base its determinations on the “best scientific

data available,” § 1533(b)(2), not the best scientific data possible, our review of the

Final Critical Habitat Designation reveals that the Service did not make a factual

finding that Units 5 and 6 were occupied by jaguars in 1972. Rather, the agency

expressed uncertainty about that question and ultimately found only that jaguars may

have occupied the units at that time.

       Moreover, there is no evidence in the record that any jaguars were present in

Units 5 and 6 between 1962 and 1982. In fact, there is no evidence that jaguars were

present in Units 5 and 6 at any time before 1995. The agency’s use of the sightings

between 1962 and 1982 was based on expert opinion that the average jaguar lifespan

is ten years; this determination is entitled to our deference. See Colo. 

(“[O]ur deference to the agency is greatest when reviewing technical matters

within its area of expertise, particularly its choice of scientific data and statistical

methodology.” (quotation omitted)). In contrast, the Service’s reliance on sightings

in 1995, 1996, and 2006 to support a conclusion of occupation in 1972 is not based

on expert opinion and is purely speculative.



                                             16
      Although we acknowledge the difficulty in ascertaining whether jaguars were

present in Units 5 and 6 in 1972, we conclude that any finding that jaguars occupied

the Units at that time is speculative and not based on substantial evidence. We

therefore agree with the district court that the Service’s designation of Units 5 and 6

as occupied critical habitat was arbitrary and capricious.

                                          III

      In the alternative, the Service determined that Units 5 and 6 met the

requirements for unoccupied critical habitat under § 1532(5)(A)(ii) and designated

them as such. Plaintiffs challenge this designation. Designation of areas as

unoccupied critical habitat must be based “upon a determination by the Secretary that

such areas are essential for the conservation of the species.” 

defines

“conservation” as “the use of all methods and procedures which are necessary to

bring any endangered species or threatened species to the point at which the measures

provided pursuant to this [Act] are no longer necessary.” § 1532(3). “Under this

definition, conservation encompasses recovery.” Ctr. for Native Ecosystems v.

Cables, 

, 1322 (10th Cir. 2007).

                                           A

      The ESA regulations in effect at the time the Service issued the Final Critical

Habitat Designation provided, “The Secretary [of the Interior] shall designate as

critical habitat areas outside the geographical area presently occupied by a species

only when a designation limited to its present range would be inadequate to ensure

the conservation of the species.” 50 C.F.R. § 424.12(e) (2013). When it

                                           17
promulgated this rule, the agency addressed comments “express[ing] concern over

the perceived possibility that Critical Habitat could be designated in an unwarranted

manner for areas outside the geographical area occupied by the species at the time of

listing.” Rules for Listing Endangered and Threatened Species, Designating Critical

Habitat, and Maintaining the Lists, 45 Fed. Reg. 13,010, 13,011 (Feb. 27, 1980). The

agency expressly rejected the suggestion that it develop “precise criteria . . . to

[e]nsure that these areas truly constitute Critical Habitat,” finding “further criteria are

unnecessary.” 

it would “closely scrutinize” any unoccupied areas and

designate them as critical habitat “only if necessary to ensure the conservation of the

species.” Id.11

       From the language of the regulatory text and the final rulemaking

accompanying it, we conclude that under § 424.12(e) (2013),12 before the Service


       11
         In 1984, the agency rejected a suggestion that it designate critical habitat
outside a species’ known range only when required to prevent the species’ extinction.
Listing Endangered and Threatened Species and Designating Critical Habitat;
Amended Procedures for Listing Endangered and Threatened Species and
Designating Critical Habitat, 49 Fed. Reg. 38,900, 38,904 (Oct. 1, 1984).
Concluding that such a limitation would be “inconsistent with the Act’s purpose of
conserving and recovering species,” the agency reiterated that critical habitat outside
of the species’ known range would be designated “when essential for the species’
conservation.” 

regulation discussed the areas “presently occupied by a species” and the
species’ “present range.” 

Although this seems to imply that
the Service should consider the species’ range at the time of designation, such a
reading would be inconsistent with the statutory requirement that the Service
consider only the “geographical area occupied by the species at the time it is listed,”
§ 1532(5)(A)(ii). See also Listing Endangered and Threatened Species and
Designating Critical Habitat; Implementing Changes to the Regulations for

                                            18
designates an area as unoccupied critical habitat, it must find designation of occupied

critical habitat “inadequate to ensure the conservation of the species.” See Markle

Interests, L.L.C. v. U.S. Fish & Wildlife Serv., 

, 470 (5th Cir. 2016)

(“Under the regulations in effect at the time that Unit 1 was designated, the Service

had to find that the species’[] occupied habitat was inadequate before it could even

consider designating unoccupied habitat as critical.”), vacated on other grounds,

(2018). But cf. Bear Valley Mut. Water Co. v. Jewell, 

,

994 (9th Cir. 2015) (holding requirements that unoccupied areas be “essential [for]

the conservation of the species” and “that the designated occupied areas are

inadequate to ensure the conservation of the species” are “identical”). The Final

Critical Habitat Designation confirmed this understanding of the regulation; it stated

that unoccupied critical habitat is designated “only when a designation limited to [the

species’] range would be inadequate to ensure the conservation of the species.” 79

Fed. Reg. at 12,578.

      Subsequent rulemakings further reflect that under the version of § 424.12(e) in

effect at the time the Service issued the Final Critical Habitat Designation, the

Service must find designation of occupied areas inadequate before designating

unoccupied critical habitat. In 2016, the agency amended the regulation and




Designating Critical Habitat, 81 Fed. Reg. 7414, 7434 (Feb. 11, 2016)
(acknowledging this “confusion”). We read § 424.12(e) (2013) to require the Service
to consider a species’ range at the time of listing, as provided in § 1532(5)(A)(ii).

                                           19
recodified it at 50 C.F.R. § 424.12(b)(2).13 The final rulemaking accompanying the

amendment explained:

      [W]e have learned from years of implementing the critical habitat
      provisions of the Act that often a rigid step-wise approach, i.e., first
      designating all occupied areas that meet the definition of “critical
      habitat” (assuming that no unoccupied habitat is designated) and then,
      only if that is not enough, designating essential unoccupied habitat, does
      not necessarily serve the best conservation strategy for the species and
      in some circumstances may result in a designation that is geographically
      larger, but less effective as a conservation tool. Our proposed change
      will allow us to consider the inclusion of occupied and unoccupied areas
      in a critical habitat designation following at minimum a general
      conservation strategy for the species.

Implementing Changes to the Regulations for Designating Critical Habitat, 81 Fed.

Reg. at 7427. The Service thus explicitly acknowledged that the prior version of the

regulation—the one at issue in this case—required a “rigid step-wise approach”

under which it must first designate occupied areas, then designate unoccupied areas

only if designation of the occupied areas is insufficient.

      The Service amended the provision yet again in 2019.14 The final rulemaking


      13
          The amended version provided, “The Secretary will identify, at a scale
determined by the Secretary to be appropriate, specific areas outside the geographical
area occupied by the species that are essential for its conservation, considering the
life history, status, and conservation needs of the species based on the best available
scientific data.” § 424.12(b)(2) (2016).
      14
           The amended regulation now provides:

      The Secretary will designate as critical habitat, at a scale determined by
      the Secretary to be appropriate, specific areas outside the geographical
      area occupied by the species only upon a determination that such areas
      are essential for the conservation of the species. When designating
      critical habitat, the Secretary will first evaluate areas occupied by the

                                           20
accompanying that amendment characterized the 2016 amendment as “chang[ing] the

step-wise approach we had been using since 1984” and “eliminating the sequenced

approach to considering occupied habitat before unoccupied habitat.” Endangered

and Threatened Wildlife and Plants; Regulations for Listing Species and Designating

Critical Habitat, 84 Fed. Reg. 45,020, 45,043 (Aug. 19, 2019). Both the 2016 and

2019 rulemakings therefore support our conclusion that § 424.12(e) (2013) required a

sequential, “step-wise” approach, under which the Service must find designation of

occupied areas inadequate as a prerequisite to designating unoccupied areas.15

                                            B

      Before considering whether the Service complied with § 424.12(e) (2013), we

note that on appeal, plaintiffs cite the regulation but do not argue that the Service

failed to comply with it. As an initial matter, we conclude that the issue is

administratively exhausted. “Parties must exhaust available administrative remedies

before the [agency] prior to bringing their grievances to federal court.” Ark Initiative


      species. The Secretary will only consider unoccupied areas to be
      essential where a critical habitat designation limited to geographical
      areas occupied would be inadequate to ensure the conservation of the
      species. In addition, for an unoccupied area to be considered essential,
      the Secretary must determine that there is a reasonable certainty both
      that the area will contribute to the conservation of the species and that
      the area contains one or more of those physical or biological features
      essential to the conservation of the species.

§ 424.12(b)(2) (2019).
      15
         We emphasize that our resolution of this case requires only an interpretation
of § 424.12(e) (2013). The 2016 and 2019 amendments to the regulation do not
affect the outcome of this case.
                                           21
v. U.S. Forest Serv., 

, 1261 (10th Cir. 2011) (quotation omitted). In

promulgating the Final Critical Habitat Designation, the Service considered the

following comment:

       The Service states in the proposed rule that [it] designate[s] critical
       habitat in areas outside the geographical area occupied by a species only
       when a designation limited to its range would be inadequate to ensure
       the conservation of the species. The area currently occupied by the
       jaguar outside the United States is adequate for the conservation of the
       jaguar.

79 Fed. Reg. at 12,615. Although the comment did not cite § 424.12(e) (2013), it

questioned the agency’s failure to find designation of occupied areas inadequate

before designating unoccupied areas as critical habitat. Because the issue was raised

“in sufficient detail to allow the agency to rectify the alleged violation,” it is

administratively exhausted. Ark 

.

       We turn to whether we may address the Service’s compliance with the

regulation, given that plaintiffs did not specifically brief the issue. Plaintiffs argue

that the Service’s designation of unoccupied jaguar habitat was arbitrary and

capricious because it did not comport with the statutory requirement that such areas

be “essential for the conservation of the species.” § 1532(5)(A)(ii). The Service

promulgated § 424.12(e) (2013) to interpret this statutory provision. See Rules for

Listing Endangered and Threatened Species, Designating Critical Habitat, and

Maintaining the Lists, 45 Fed. Reg. at 13,011. At the district court, plaintiffs and the

Service quoted the regulation in their briefs. Further, plaintiffs requested

“declaratory judgment and injunctive relief against the Defendants for violating . . .


                                            22
50 C.F.R. § 424.12(e).” On appeal, plaintiffs and the Service quote the regulation in

their briefs. Plaintiffs do not challenge the validity of the regulation, thereby

acknowledging that it defines the agency’s obligations when designating unoccupied

critical habitat. But they do not request that we overturn the Final Critical Habitat

Designation because it did not comply with § 424.12(e) (2013). Rather, plaintiffs

challenge the agency action only on statutory grounds. They ask us to define the

word “essential” restrictively, not raising the narrower, related issue of whether the

Service complied with the regulation.

      In the context of arguments raised before us but not before the district court,

we have held that the “general waiver rule is not absolute, . . . and we may depart

from it in our discretion, particularly when we are presented with a strictly legal

question, the proper resolution of which is beyond doubt or when manifest injustice

would otherwise result.” Sussman v. Patterson, 

, 1210 (10th Cir. 1997)

(alteration and quotation omitted); see also Greene v. Safeway Stores, Inc., 

, 1243 (10th Cir. 2000) (exercising discretion to consider waived argument

because “the issue presented is one of law”). In such cases, we may exercise

discretion when “the record is sufficient to resolve the issue on its merits.” Hooker

v. Mullin, 

, 1241 n.7 (10th Cir. 2002). Similarly, in cases in which

appellate briefs are deficient because they do not comply with the Federal Rules of

Appellate Procedure, we have held that “the court in its discretion may scrutinize the

merits of the case insofar as the record permits.” MacArthur v. San Juan Cty., 

, 1161 (10th Cir. 2007); see also Burke v. Regalado, 

, 1031

                                           23
(10th Cir. 2019) (relying on a “detailed motion . . . filed in the district court” because

the appellate briefing was inadequate).

      Plaintiffs do not challenge the validity of § 424.12(e) (2013), which interprets

§ 1532(5)(A)(ii); they only contest the Service’s compliance with the statute. But

when we consider an agency action made pursuant to a statute and an implementing

regulation, we cannot ignore the regulatory context when determining whether that

action was arbitrary and capricious. In this case, whether the Service complied with

the regulation is a strictly legal question that we are fully capable of resolving on the

administrative record alone. As set forth below, that record leads us to conclude the

agency did not comply with the regulation, and our resolution of this issue is beyond

doubt. Further, the agency had a chance to rectify this error, but failed to do so.

Thus, instead of addressing plaintiffs’ statutory argument—that the Service’s

designation of Units 5 and 6 as unoccupied critical habitat is arbitrary and capricious

because the areas were not “essential for the conservation of the species” under

§ 1532(5)(A)(ii)—we exercise our discretion to consider whether the Service

complied with the requirements of § 424.12(e) (2013).

                                            C

      Turning to the merits of the issue, we have held that “[a]gencies are under an

obligation to follow their own regulations, procedures, and precedents, or provide a

rational explanation for their departure.” Utahns for Better Transp. v. U.S. Dep’t of

Transp., 

, 1165 (10th Cir. 2002). When an agency does not comply

with its own regulations, it acts arbitrarily and capriciously. 

see also

                                            24
Cherokee Nation of Okla. v. Norton, 

, 1078 (10th Cir. 2004) (“[The

APA] require[s] agencies, on pain of being found to have acted arbitrarily and

capriciously, to comply with their own regulations.”).16

      In the Final Critical Habitat Designation, the Service “acknowledge[d] that the

lack of jaguar sightings at the time the species was listed as endangered in 1972 . . .

suggest[ed] that jaguars in the United States had declined to such an extent by that

point as to be effectively eliminated.” 79 Fed. Reg. at 12,588 (citation omitted). It

continued:

      To the extent that areas described above may not have been occupied at
      the time of listing, we determine that they are essential to the
      conservation of the species for the following reasons: (1) They have
      demonstrated recent (since 1996) occupancy by jaguars; (2) they contain
      features that comprise suitable jaguar habitat; and (3) they contribute to
      the species’ persistence in the United States by allowing the normal
      demographic function and possible range expansion of the proposed
      Northwestern Recovery Unit, which is essential to the conservation of
      the species.

extent that any Units were occupied in 1972, the Service was required

to find that their designation as critical habitat was inadequate to ensure jaguar

conservation before it designated Units 5 and 6, which were unoccupied, as critical

habitat. It did not so do. The Service did not find that the designation of areas

occupied by jaguars in 1972 would be inadequate to ensure the conservation of the


      16
        An agency’s interpretation of its own regulations may be entitled to
deference if the regulation is “genuinely ambiguous.” Kisor v. Wilkie, 

, 2414 (2019). But § 424.12(e) (2013) is not ambiguous.

                                           25
species. Nor did it make findings about whether any individual unit designated as

unoccupied was essential for the conservation of the species.17 Rather, it addressed

all the units together, finding that to the extent they were not occupied, they were

essential for the conservation of the species.

      We conclude the agency did not comply with its obligation to designate

unoccupied critical habitat “only when a designation limited to its present range

would be inadequate to ensure the conservation of the species.” § 424.12(e) (2013).

Because it did not follow its own regulations or provide a rational explanation for

failing to do so, its designation of Units 5 and 6 as critical habitat was arbitrary and

capricious.

                                           IV

      Plaintiffs also argue that because Units 5 and 6 are “secondary,” “marginal”

habitat and constitute only a small portion of the jaguar’s range, they cannot be

essential for the conservation of the species. We disagree. The Service convened a

Jaguar Recovery Team, which prepared a Recovery Outline for the jaguar. See Final

Critical Habitat Designation, 79 Fed. Reg. at 12,573-74. The Recovery Outline maps

the “Northwestern Recovery Unit,” including jaguar habitat in the United States and


      17
         The Final Critical Habitat Designation did include specific findings
pertaining to Units 1b, 4b, and 4c, for which there was no evidence of jaguar
occupation at any time. 

The Service found that “maintaining travel
corridors to Mexico is essential for the conservation of jaguars in the Northwestern
Recovery Unit, and, therefore, for the species as a whole.” 

Because
Units 1a and 4a do not border Mexico, the Service specifically found Units 1b, 4b,
and 4c were essential for the conservation of the species because they connected
Units 1a and 4a to Mexico. 

                                           26
northwestern Mexico. See 

The Northwestern Recovery Unit comprises

only a small portion of the jaguar’s range and is divided into so-called “core” and

“secondary” areas. See 

exhibit evidence of consistent jaguar presence

and recent reproduction, whereas secondary areas are characterized by recent records

of jaguar presence but little evidence of reproduction. The portion of the

Northwestern Recovery Unit in the United States, which encompasses all of Units 1

to 6, is part of the Borderlands Secondary Area; the nearest core area—the Sonora

Core Area—is about 130 miles south of the U.S.-Mexico border. 

open, dry habitat of the southwestern United States has been characterized as

marginal habitat for jaguars in terms of water, cover, and prey densities.” 

       In the Final Critical Habitat Designation, the Service stated that the areas

designated as critical habitat contribute to jaguar conservation because they “support

some individuals during dispersal movements, provide small patches of habitat

(perhaps in some cases with a few resident jaguars), and provide areas for cyclic

expansion and contraction of the nearest core area.” 

Jaguars

“dispersing into the United States are important,” the Service explained, “because

they occupy habitat that serves as a buffer to zones of regular reproduction and are

potential colonizers of vacant range.” 

areas supporting them are

important to maintaining normal demographics, as well as allowing for possible

range expansion.” 

also found that “the Northwestern Recovery Unit

is essential for the conservation of the species,” and that “[c]ritical habitat in the

                                            27
United States contributes to recovery across the species’ entire range.” 

12,605. In our view, it is not inconsistent for the Service to find both that Units 5

and 6 are “secondary” or “marginal” habitat and that they are essential for the

conservation of the jaguar.

                                           V

      Finally, plaintiffs contend that because the ESA limits “conservation” to those

methods and procedures necessary to bring a species “to the point at which the

measures provided pursuant to this chapter are no longer necessary,” § 1532(3), the

Service was required to identify this “point” when it designated the jaguar’s critical

habitat. But the ESA’s detailed provisions regarding designation of critical habitat

include no such requirement. See Markle 

(“The ESA’s

critical-habitat provisions do not require the Service to know when a protected

species will be conserved as a result of the designation.”), vacated on other 

; Home Builders Ass’n of N. Cal. v. U.S. Fish & Wildlife Serv., 

, 989 (9th Cir. 2010) (“[T]here is no reason why [the Service] cannot

determine what elements are necessary for conservation without determining exactly

when conservation will be complete. . . . [T]he statute actually runs contrary to [this]

argument.”). Moreover, in a different provision governing recovery plans, the ESA

requires the Service to identify “objective, measurable criteria which, when met,

would result in a determination, in accordance with the provisions of this section, that

the species be removed from the list.” § 1533(f)(1)(B)(ii). This requirement is

entirely separate from the requirements for the designation of critical habitat. See

                                           28
Hamdan v. Rumsfeld, 

, 578 (2006) (“Where Congress includes

particular language in one section of a statute but omits it in another section of the

same Act, it is generally presumed that Congress acts intentionally and purposely in

the disparate inclusion or exclusion” (alteration and quotation omitted)).

Accordingly, we hold the ESA does not require the Service to identify the point at

which a species will be considered to have recovered when it designates critical

habitat for that species.18

                                           VI

       For the foregoing reasons, we REVERSE the decision of the district court and

REMAND for proceedings consistent with this decision.




       18
         Plaintiffs also argue that the Service’s designation of Unit 6 as critical
habitat was arbitrary and capricious because the unit does not contain the “physical
and biological features essential to the conservation of the species” under
§ 1532(5)(A)(i). They misread the statute, which unambiguously imposes this
requirement only on occupied areas designated as critical habitat, not on unoccupied
areas. Further, this argument was forfeited because it was not raised during the
notice-and-comment period. See Dep’t of Transp. v. Pub. Citizen, 

,
764-65 (2004).
                                           29
17-2211, NM Farm & Livestock Bureau v. U.S. Department of Interior

HARTZ, J., Circuit Judge, concurring

       I join in full Judge Lucero’s opinion. I add only one observation. The

administrative record raises concerns about whether the Service defined essential to mean

merely convenient or helpful. But I am confident that it will be more careful after

remand.