                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

IN DEFENSE OF ANIMALS;                 No. 12-17804
DREAMCATCHER WILD HORSE AND
BURRO SANCTUARY; BARBARA                  D.C. No.
CLARKE; CHAD HANSON; LINDA             2:10-cv-01852-
HAY,                                     MCE-DAD
              Plaintiffs-Appellants,

                 v.                      OPINION

U.S. DEPARTMENT OF THE INTERIOR;
BUREAU OF LAND MANAGEMENT;
SALLY JEWELL,* Secretary of the
U.S. Department of the Interior;
NEIL KORNZE,** Director of the
Bureau of Land Management; KEN
COLLUM,*** Field Manager of Eagle
Lake Field Office,
              Defendants-Appellees,

SAFARI CLUB INTERNATIONAL;
SAFARI CLUB INTERNATIONAL
FOUNDATION,
  Intervenor-Defendants–Appellees.
2        IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

           Appeal from the United States District Court
               for the Eastern District of California
        Morrison C. England, Chief District Judge, Presiding

                      Argued and Submitted
              August 29, 2013—Pasadena, California

                        Filed May 12, 2014

        Before: Mary M. Schroeder, Johnnie B. Rawlinson,
                and Carlos T. Bea, Circuit Judges.

                      Opinion by Judge Bea;
                    Dissent by Judge Rawlinson




    *
   Sally Jewell is substituted for her predecessor, Kenneth L. Salazar, as
Secretary of the Interior. Fed. R. App. P. 43(c)(2).
        **
      Neil Kornze is substituted for his predecessor, Robert Abbey, as
Director of the Bureau of Land Management. Fed. R. App. P. 43(c)(2).
    ***
        Ken Collum is substituted for his predecessor, Dayne Barron, as
Field Manager of Eagle Lake Field Office. Fed. R. App. P. 43(c)(2).
     IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR                     3

                          SUMMARY****


                 Bureau of Land Management

    The panel affirmed the district court’s summary judgment
in favor of federal defendants in an action alleging that the
roundup, or gather, of wild horses and burros from the Twin
Peaks Herd Management Area on the California-Nevada
border violated the Wild Free-Roaming Horses and Burros
Act and the National Environmental Policy Act.

   Pursuant to its authority under the Wild Free-Roaming
Horses and Burros Act (the “Act”), the Bureau of Land
Management (“BLM”) establishes Appropriate Management
Levels for populations of native species - including wild
horses and burros - and introduced animals, such as livestock.
The BLM removes animals from the Herd Management Area
when the population exceeds the established Appropriate
Management Level.

    The panel held that the BLM acted within its authority
under the Act when it implemented the 2010 Gather Plan on
the Twin Peaks Herd Management Area. The panel also held
that the BLM’s decision not to prepare an environmental
impact statement under the National Environmental Policy
Act (“NEPA”) was not arbitrary and capricious because the
BLM provided a convincing statement of reasons why the
gather’s environmental effects would not be significant. The
panel also held that the BLM did not act arbitrarily and
capriciously under NEPA when it responded to comments

 ****
      This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
4   IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

highlighting the possibility of scientific dissent regarding the
administration of the immunocontraceptive PZP.

    Judge Rawlinson dissented because she did not agree that
the roundup of the wild horses by the BLM complied with the
Act.


                         COUNSEL

Rachel M. Fazio, Cedar Ridge, California, for Plaintiffs-
Appellants.

Ignacia S. Moreno, Assistant Attorney General; Nancy
Zahedi, United States Department of the Interior, Office of
Regional Solicitor; Erik E. Petersen, Ayako Sato, and Mark
R. Haag, United States Department of Justice, Environment
& Natural Resources Division, Washington, D.C., for
Defendants-Appellees.

Douglas Scott Burdin and Anna Seidman, Safari Club
International, Washington, D.C., for Intervenor-Defendants–
Appellees.


                          OPINION

BEA, Circuit Judge:

    Wild horses—mustangs—and burros are part of our
nation’s heritage from the American West; a heritage
Congress has sought to preserve. That these animals should
roam the Western spaces appeals to the nature lover and
historian in each of us.
    IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR            5

   But these animals eat and trample. Even in the wide open
West of our nation, there is just so much forage; there are also
many vulnerable cultural artifacts underfoot.

    These animals also multiply. And when too many of
them abound in limited land, the congressionally-appointed
stewards of that land must act to protect the environment.

    This case is about whether those stewards have followed
Congress’s rules and their own agency’s regulations in acting
to thin the herds of these sympathetic, even inspiring, but
voracious, animals.

    Plaintiffs—two non-profit organizations dedicated to
protecting wild horses and burros, and members of these
organizations—appeal the district court’s grant of summary
judgment to the United States Department of the Interior and
the Bureau of Land Management (“BLM”) (collectively
“Defendants”) regarding the roundup, or “gather,” of
approximately 1,600 wild horses and 160 burros from the
Twin Peaks Herd Management Area (“HMA”) on the
California-Nevada border. Plaintiffs claim the gather
violated the Wild Free-Roaming Horses and Burros Act (“the
Act”) and the National Environmental Policy Act (“NEPA”).
The district court found no violation of either statute. We
AFFIRM.

                        Background

    This case arises out of a roundup of wild horses and
burros by the BLM. The roundup took place in August and
September 2010 on the Twin Peaks HMA. In 1981, the BLM
designated the Twin Peaks HMA—nearly 800,000 acres of
public and private land on either side of the California-
6           IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

Nevada border—as suitable for the long-term maintenance of
wild horses and burros. Pursuant to its authority under the
Act,1 the BLM is charged with managing the Twin Peaks
HMA to “achieve and maintain a thriving natural ecological
balance.” 16 U.S.C. § 1333(a). The BLM accomplishes this
goal, in part, by establishing Appropriate Management Levels
(“AMLs”) for populations of both native species—including
wild horses, burros, and other wildlife—and introduced
animals, such as livestock (including cattle and sheep).2 43
C.F.R. § 4710.3-1. The BLM removes animals from an HMA
when the population exceeds the established AML. Under
the Act, the BLM must remove these excess animals in the
following “order and priority”: first, the BLM “shall order
old, sick, or lame animals to be destroyed in the most humane
manner possible”; second, the BLM “shall . . . capture[] and
remove[]” additional excess animals “for private
maintenance,” including adoption; third, the BLM “shall . . .
destroy[]” additional excess animals.3 § 1333(b)(2).


        1
       The Wild Free-Roaming Horses and Burros Act, 16 U.S.C.
§ 1331–1340, was enacted in 1971, and states its general purpose as
protecting “wild free-roaming horses and burros [] from capture, branding,
harassment, or death; and to accomplish this they are to be considered in
the area where presently found, as an integral part of the natural system of
the public lands.” 16 U.S.C. § 1331.
  2
    There is a separate AML for each species on a given HMA. The AML
for wild horses is defined by the BLM “as the number of wild horses that
can be sustained within a designated HMA which achieves and maintains
a thriving natural ecological balance in keeping with the multiple-use
management concept for the area.”
    3
    As the district court noted, “Congress has never appropriated funds for
extermination, as opposed to ongoing maintenance, of excess horses even
if not adopted.” In Defense of Animals v. U.S. Dep’t of the Interior, 909
F. Supp. 2d 1178, 1190 (E.D. Cal. 2012); see, e.g., Pub. L. 111-88,
      IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR                      7

    In 1989, the BLM first set AMLs for wild horses and
burros on the Twin Peaks HMA. Since then, it has adjusted
these AMLs several times to address the degradation of
riparian and wetland sites.4 At the time of the 2010 gather,
the AML amount for the Twin Peaks HMA was set at
448–758 wild horses and 72–116 burros. This amount was
set in 2001 and was confirmed in the 2008 Eagle Lake
Resource Management Plan.

    Since 1998, the population of wild horses and burros on
the Twin Peaks HMA has steadily increased despite nine
BLM gathers and consequent removals. In May 2010, before
the challenged gather, the HMA was home to approximately
2,303 wild horses and 282 burros, or close to 300% more
wild horses and 240% more burros than the permissible
highest number of their respective AMLs. At that time, the
BLM projected that, if left unchecked, the wild horse
population on the HMA could exceed 6,000 to 8,000 within
ten years. Compounding this situation, according to the
BLM, wild horses were consuming three to five times as
much forage as was allocated for their use. The BLM
predicted that, if left unchecked, this overpopulation of wild
horses and burros would cause “serious impacts to soil
stability, vegetation, water sources (springs and creeks), and
wildlife habitat,” and “would not allow for sufficient
availability of forage and water for either wild horses or other



123 Stat. 2904, 2907 (2009) (“Appropriations herein made shall not be
available for the destruction of healthy, unadopted, wild horses and burros
in the care of the Bureau of Land Management or its contractors.”).
  4
     According to the BLM, “riparian and wetland sites” include both
“lentic” and “lotic” sites. Lentic sites consist of springs and seeps. Lotic
sites consist of creeks, streams, and reservoirs.
8       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

animals.” The BLM also noted that the “increased numbers
of wild horses over the past five years appear[ed] to be
having a significant adverse impact [on cultural] sites.”5

    In May 2010, after soliciting comments from 250 sources,
and based in part on the BLM’s stated predictions, the BLM
released a 157-page Environmental Assessment (“EA”) for its
Twin Peaks HMA Wild Horse and Burro Gather Plan
(“Gather Plan”). “To reduce the impacts associated with an
overpopulation of wild horses [and to] ensure that rangeland
and riparian resources are capable of meeting land health
standards,” the EA proposed to remove excess wild horses
and burros from the HMA. The EA noted that the proposed
action was “needed at this time to balance wild horse and
burro populations with other resources, including wildlife
habitat, wilderness study area values, cultural resources,
livestock grazing, and soil and vegetation resources.”

    According to the proposed action analyzed by the EA, the
BLM would attempt to gather up to 2,300 wild horses and
210 burros from the Twin Peaks HMA and would then return
a certain number of both animals to the HMA such that the
total remaining populations were within the designated
AMLs. The BLM planned to use “a helicopter drive method
of capture, with occasional helicopter assisted roping from
horseback” to steer the animals into “trap sites” where the
animals would be held until they could be transported to
temporary holding facilities on the HMA. Once in the


    5
    “Cultural sites” refer to areas and artifacts which reflect the Twin
Peaks’ American Indian history. The BLM has estimated that over 1,500
such cultural sites exist within the Twin Peaks HMA, including tool-stone
quarries, prehistoric camp sites and rockshelters, petroglyphs (rock
drawings), and trails.
        IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR                   9

temporary holding facilities, the BLM would feed the
animals, sort them based on sex, and examine the animals’
conditions before deciding whether individual animals should
be euthanized because of injury or age, put up for adoption,
or returned to the HMA.6 To curb future population
increases, the released wild horses would have a 60:40 studs-
to-mares (male-to-female) ratio, and the released mares
would be injected with an immunocontraceptive, Porcine
Zona Pellucida (“PZP”), which would reduce their fertility
for two years.

    The EA described the actions the BLM would take to
ensure the helicopter gather process would not unnecessarily
stress the animals and maintained that the capture methods,
traps, holding facilities, equipment, safety procedures, and
administration of PZP would comply with the BLM’s
Standard Operating Procedures for such gathers. The EA also
provided a detailed analysis of an alternative gather plan that
would not involve any fertility control measures, an
alternative that would use only fertility control measures but
no herd thinning or relocation, and a no-action alternative.7
The EA examined the potential impacts of these alternatives
on the HMA’s environment, looking specifically at the
impact on areas of critical environmental concern, cultural


  6
    Remember, although the Act authorizes the “humane” destruction of
excess healthy wild horses and burros, Congress has prohibited the
authorization of funds to be spent to do so. See supra n.3. If not adopted,
BLM transfers the healthy excess animals to private long-term holding
facilities, which consist of grassland pastures in the Midwest averaging
approximately 10–11 acres per horse.
    7
       The EA also gave brief consideration to fourteen additional
alternatives, which the BLM concluded were either impracticable or
unresponsive to the need to remove excess animals.
10 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

resources, livestock grazing, noxious weeds and invasive
species, riparian and wetland sites, soil resources, special
status plants, upland vegetation, native wildlife, and
wilderness study areas.

    In July 2010, based on its detailed consideration in the
EA, the BLM issued a “Finding of No Significant Impact”
(“FONSI”) on the environment for the proposed gather from
the Gather Plan, and therefore did not prepare an
environmental impact statement (“EIS”).8 On the same day,
the BLM announced that it would implement the proposed
gather and also responded to comments it had received on the
EA.

    Before the BLM conducted the proposed gather, Plaintiffs
filed suit against the Defendants to enjoin implementation of
the proposed gather. Plaintiffs alleged the proposed gather
would violate the Act and the EIS-requirement of NEPA.
The district court denied Plaintiffs’ motion for a preliminary
injunction, and Plaintiffs appealed.

   After a motions panel of this court denied an emergency
motion for injunctive relief pending appeal on August 10,
2010, the gather took place during August and September of
2010. The BLM ultimately gathered approximately 1,639
wild horses and 160 burros. The parties agree that post-


 8
   As discussed in more detail infra Part B, NEPA requires an agency to
complete an EIS only when substantial questions are raised as to whether
a proposed project “may cause significant degradation of some human
environmental factor.” Pub. Citizen v. Nuclear Regulatory Comm’n,
573 F.3d 916, 929 (9th Cir. 2009) (quoting Ctr. for Biological Diversity
v. Nat’l Highway Traffic Safety Admin., 538 F.3d 1172, 1219 (9th Cir.
2008)).
     IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 11

gather, 793 wild horses and 160 burros resided on the HMA.9
The remaining wild horses were made available for adoption
or sale, or placed in long-term holding facilities.

    On August 15, 2011, this panel denied Plaintiffs’
preliminary injunction appeal because the injunctive relief
sought had become moot. In Defense of Animals v. U.S.
Dep’t of Interior, 648 F.3d 1012 (9th Cir. 2011). The parties
then filed cross motions for summary judgment in the district
court. The district court granted Defendants summary
judgment, holding that the gather did not violate the Act or
NEPA. Plaintiffs timely appealed.

                       Standard of Review

    This court reviews de novo a grant of summary judgment.
 Guatay Christian Fellowship v. Cnty. of San Diego, 670 F.3d
957, 970 (9th Cir. 2011). We “must determine, viewing the
evidence in the light most favorable to the nonmoving party,
whether the district court correctly applied the relevant
substantive law and whether there are any genuine issues of
material fact.” Balint v. Carson City, 180 F.3d 1047, 1050
(9th Cir. 1999) (en banc).

    Because neither NEPA nor the Act contain an internal
standard of judicial review, the Administrative Procedure Act
governs this court’s review of the BLM’s actions. Ocean
Advocates v. U.S. Army Corps of Eng’rs, 402 F.3d 846,
858–59 (9th Cir. 2005). This court must set aside the BLM’s
actions, findings, or conclusions if they are “arbitrary,


 9
    According to the BLM, fifty-eight horses and one burro were returned
to the Twin Peaks HMA after the gather and two horses were euthanized
on the HMA due to pre-existing, debilitating leg injuries.
12 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

capricious, an abuse of discretion, or otherwise not in
accordance with law.” 5 U.S.C. § 706(2)(A). Although this
review is “searching and careful,” the arbitrary and capricious
standard is narrow, and this court cannot substitute its own
judgment for that of the agency. Ocean Advocates, 402 F.3d
at 858 (citation omitted). An agency’s decision is arbitrary
and capricious if it fails to consider important aspects of the
issue before it, if it supports its decisions with explanations
contrary to the evidence, or if its decision is either inherently
implausible or contrary to governing law. The Lands Council
v. Powell, 395 F.3d 1019, 1026 (9th Cir. 2005).

                           Analysis

A. Plaintiffs’ Wild Free-Roaming Horses and Burros Act
   claims

    The Act directs the Secretary of the Interior (“Secretary”)
to “protect and manage wild free-roaming horses and burros
as components of the public lands . . . .” 16 U.S.C. § 1333(a).
The BLM, as the designate of the Secretary, “shall manage
wild free-roaming horses and burros in a manner that is
designed to achieve and maintain a thriving natural ecological
balance on the public lands.” Id. The BLM must also
“maintain a current inventory of wild free-roaming horses and
burros on given areas of the public lands.” § 1333(b)(1). As
Congress explained:

        The purpose of such inventory shall be to:
        make determinations as to whether and where
        an overpopulation exists and whether action
        should be taken to remove excess animals;
        determine appropriate management levels of
        wild free-roaming horses and burros on these
      IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 13

        areas of the public lands; and determine
        whether appropriate management levels
        should be achieved by the removal or
        destruction of excess animals, or other options
        (such as sterilization, or natural controls on
        population levels).

Id.

    Congress provided that “[a]ll management activities shall
be at the minimal feasible level . . . .” § 1333(a). Yet the Act
also provides that if the current population inventory reveals
that “an overpopulation exists on a given area of the public
lands,” and if the BLM determines that “action is necessary
to remove excess animals,” the BLM “shall immediately
remove excess animals from the range so as to achieve
appropriate management levels.” § 1333(b)(2). The Act
defines “excess animals” as “wild free-roaming horses or
burros . . . which must be removed from an area in order to
preserve and maintain a thriving natural ecological balance
and multiple-use relationship in that area.” § 1332(f). Thus,
while the overarching purpose of the Act is to protect wild
horses and burros from “capture, branding, harassment or
death,” § 1331, the BLM is required to remove wild horses
and burros from a given area of the public lands when an
overpopulation exists.

    In removing “excess animals,” the Act instructs the BLM
to take action

        in the following order and priority, until all
        excess animals have been removed so as to
        restore a thriving natural ecological balance to
14 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

       the range, and protect the range from the
       deterioration associated with overpopulation:

       (A) The Secretary shall order old, sick, or
       lame animals to be destroyed in the most
       humane manner possible;

       (B) The Secretary shall cause such number of
       additional excess wild free-roaming horses
       and burros to be humanely captured and
       removed for private maintenance and care for
       which he determines an adoption demand
       exists . . . ;

       (C) The Secretary shall cause additional
       excess wild free-roaming horses and burros
       for which an adoption demand by qualified
       individuals does not exist to be destroyed in
       the most humane and cost efficient manner
       possible.

§ 1333(b)(2) (emphasis added).

   Plaintiffs make five arguments why the BLM violated the
Act by implementing the proposed gather, but none of these
arguments prevail.

    First, Plaintiffs claim the BLM failed to determine, before
the gather, that there were “excess” wild horses and burros on
the Twin Peaks HMA. However, as earlier noted, the BLM
had set AMLs for wild horses and burros on the HMA
through the 2008 Eagle Lake Resource Management Plan at
448–758 and 72–116, respectively, and determined, prior to
the gather, that these AMLs had been vastly exceeded. In the
       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 15

EA, the BLM specifically found that there were 1,855 excess
wild horses and 210 excess burros within the HMA.10 Given
the undisputed fact that the wild horse and burro populations
greatly exceeded their respective AMLs at the time of the
gather, and the carefully-documented concerns about the
deterioration of riparian areas and cultural sites caused by
overpopulation, as well as the likelihood of insufficient
forage to sustain the growing herd,11 the BLM properly
decided action was necessary to restore the AMLs.12


  10
     This careful determination of AMLs for the wild horses and burros,
and the calculation of the excess population, distinguishes this case from
Colorado Wild Horse and Burro Coalition v. Salazar, 639 F. Supp. 2d 87
(D.D.C. 2009). In Salazar, the BLM proposed the permanent removal of
the entire wild horse herd from the West Douglas Herd Area in Colorado,
but failed to establish an AML for the herd or to demonstrate that there
were excess numbers of wild horses on the public lands. Id. at 95. A non-
profit organization challenged the proposed gather as violative of the Act’s
requirement that the BLM keep an inventory of wild horses on public
lands and determine that there are excess animals before removing them.
Id. at 89. The district court agreed and held that the proposed gather,
which had been planned without any determination that an overpopulation
existed or that there were excess wild horses on the public lands, violated
the Act. Id. at 98. Here, to the contrary, the BLM fulfilled its statutory
duty by keeping an inventory of wild horse and burro populations on the
Twin Peaks HMA and making detailed calculations of the excess animals
on the HMA.
   11
      Indeed, in its decision to implement the Gather Plan, the BLM
predicted that if no action were taken to restore the AMLs, the wild horse
population would “crash . . . based on a lack of forage and water, and from
extreme competition and stress to the animals.”
 12
    According to the EA, some riparian/wetland areas were “not meeting
the [Riparian Proper Functioning Condition] standard” in May 2010
because of “[h]igh utilization and trampling by excess numbers of wild
horses.” Moreover, “many [riparian/wetland] sites appear[ed] to be in a
downward trend and [were] at risk of becoming more severely degraded
16 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

    Plaintiffs claim that, to find that there were “excess
animals,” the BLM was required to determine that there was
not a “thriving natural ecological balance” on the HMA due
to the presence of wild horses and burros at the time of the
gather. Plaintiffs cite 16 U.S.C. § 1332(f)(2), which defines
“excess animals” as those animals which “must be removed
from an area in order to preserve and maintain a thriving
natural ecological balance . . . .” This argument fails.
Preservation efforts can hardly require prior destruction of
what is to be preserved. Simply because removal is required
when necessary to “preserve and maintain” such a “thriving
natural ecological balance” does not mean that removal can
occur only when there is a showing that such a balance no
longer exists. Rather, the use of the phrase “preserve and
maintain” in the definition of “excess animals” suggests that
the BLM may determine removal is necessary to ensure that
the current thriving natural ecological balance does not
deteriorate in the future.

    Additionally, as the district court held, the statute
determines “excess animals” through the use of AML levels.
In Defense of Animals v. U.S. Dep’t of Interior, 909 F. Supp.
2d 1178, 1192 (E.D. Cal. 2012); 16 U.S.C. § 1333(b)(2) (if
“an overpopulation exists,” and if the BLM determines that
“action is necessary to remove excess animals,” the BLM
“shall immediately remove excess animals from the range so
as to achieve appropriate management levels.”) (emphasis
added). Although the statute also provides that “[s]uch action
shall be taken . . . until all excess animals have been removed


if [the then-current] level of use from wild horses [was] not curtailed.”
Finally, the BLM determined that “[t]he increased numbers of wild horses
over the past five years appear[ed] to be having a significant adverse
impact to [cultural] sites.”
       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 17

so as to restore a thriving natural ecological balance,” the
most logical reading of those two phrases together is that the
BLM must achieve a “thriving natural ecological balance” by
maintaining the relevant AMLs. § 1333(b)(2). In this way,
“AML is a vehicle used to move towards a [thriving natural
ecological balance], and a trigger by which [] the BLM is
alerted to address population imbalance.” In Defense of
Animals, 909 F. Supp. 2d at 1192; see also Am. Horse
Protection Ass’n, Inc. v. Watt, 694 F.2d 1310, 1318 (D.C. Cir.
1982) (The Act “directs that horses ‘shall’ be removed
‘immediately’ once the Secretary determines, on the basis of
whatever information he has at the time of his decision, that
an overpopulation exists.”) (emphasis omitted). Thus, the
BLM correctly relied on the AMLs to decide that there were
excess wild horses and burros on the HMA, and Plaintiffs’
assertion that a “thriving natural ecological balance” was
being maintained on the Twin Peaks HMA before the gather
is irrelevant.13

   Second, Plaintiffs contend the BLM violated the “order
and priority” provision of the Act, 16 U.S.C. § 1333(b)(2),14

 13
    Although Plaintiffs fault the BLM for relying on “decade-old” AMLs
from 2001without conducting a new analysis, the 2008 Eagle Lake
Resource Management Plan “validated” those AMLs. Regardless, nothing
in the Act requires the BLM to determine new AMLs based on current
conditions every time the BLM decides to take action to restore the
already-established AMLs.
 14
      Section 1333(b)(2) provides, in relevant part:

           Where the Secretary determines . . . that an
           overpopulation exists on a given area of the public
           lands and that action is necessary to remove excess
           animals, he shall immediately remove excess animals
           from the range so as to achieve appropriate
18 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

by failing to identify and euthanize the “old, sick, or lame”
animals on the HMA before “capturing” or “removing” the
adoptable horses and burros. The BLM responds that the
term “remove” in § 1333(b)(2) should be interpreted to refer
to the permanent removal of animals from the HMA, and not
the temporary gathering of animals on the HMA to determine
which animals should be euthanized and which animals
should be made available for adoption. The BLM therefore
claims that “the Gather Plan’s temporary gathering of animals
on the [HMA] is not itself a removal and is therefore not
governed by Section 1333(b)(2)’s order and priority
provision.” We agree with the BLM.

    The Act does not define “remove” as it is used in
§ 1333(b)(2) to prescribe the order for removal of excess wild
horses and burros. However, the Act does direct the BLM to


        management levels. Such action shall be taken, in the
        following order and priority, until all excess animals
        have been removed . . .

        (A) The Secretary shall order old, sick, or lame animals
        to be destroyed in the most humane manner possible;

        (B) The Secretary shall cause such number of additional
        excess wild free-roaming horses and burros to be
        humanely captured and removed for private
        maintenance and care for which he determines an
        adoption demand exists . . . ;

        (C) The Secretary shall cause additional excess wild
        free-roaming horses and burros for which an adoption
        demand by qualified individuals does not exist to be
        destroyed in the most humane and cost efficient manner
        possible.

(emphasis added).
       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 19

“immediately remove excess animals from the range.”
§ 1333(b)(2) (emphasis added). Moreover, none of the three
methods for removal provided for by the “order and priority”
provision (euthanization of old, sick, or lame animals; private
maintenance; and destruction of additional excess animals)
contemplate “removal”of the animals by temporarily
capturing those animals on the HMA. Therefore, we interpret
the term “remove” in § 1333(b)(2) to mean the transfer of
wild horses and burros from the public lands on which they
once lived to private lands for private maintenance, or the
destruction of such animals pursuant to § 1333(b)(2)(A) or
(C).15 Under this interpretation, the gather’s temporary
roundup of nearly all the wild horses and burros on the HMA
was not itself a “removal” that is governed by the order and
priority provision of the Act, and therefore the BLM did not
violate this provision. See In Defense of Animals v. Salazar,
675 F. Supp. 2d 89, 97 (D.D.C. 2009) (holding that rounding
up the vast majority of a wild horse herd for sorting in a
nearby holding facility does not “remove” all horses from the
public lands in violation of the Act’s order and priority
provision).

   In sum, the BLM’s actions fell within the discretion
which courts have recognized the BLM has to remove excess




  15
    In the EA, the BLM interpreted “remove” to refer to the permanent
removal of the animals from the HMA, while it used the term “gather” to
describe the temporary herding and holding of the animals for purposes of
identification and diagnosis. We need not determine what, if any, level of
deference this determination is due because we have concluded that the
plain language of the statute is not ambiguous. See, Chevron, U.S.A., Inc.
v. Natural Res. Def. Council, Inc., 467 U.S. 837, 842 (1984) (“If the intent
of Congress is clear, that is the end of the matter.”).
20 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

animals from an HMA.16 When faced with the task of having
to remove a large percentage of the wild horse and burro
population to maintain the AMLs, the BLM reasonably
determined that the most effective way to fulfill its statutory
mandate was to attempt temporarily to gather the entire herd
before making determinations as to which animals should be
euthanized, which animals should be permanently removed
via adoption, and which animals should be released back on
to the HMA.17

    Third, Plaintiffs argue that because the gather will likely
result in a level of livestock grazing that is allegedly three
times higher than the level of wild horse and burro grazing,
the gather violated the Act’s purported mandate that the
Twin Peaks HMA be managed “principally but not
necessarily exclusively” for the welfare of wild horses and
burros. Plaintiffs rely on language in the Act which defines
“ranges,” which are to be designated by the Secretary as
“sanctuaries for the protection and preservation” of wild
horses and burros, see 16 U.S.C. § 1333(a), as “the amount of
land . . . which is devoted principally but not necessarily

  16
    See, e.g., Cloud Found., Inc. v. Kempthorne, 2008 WL 2794741, at
*11 (D. Mont. July 16, 2008) (“The BLM has broad discretion under the
Act, and the arbitrary and capricious standard of review from the APA is
highly deferential”); Am. Horse Protection Ass’n v. Frizzell, 403 F. Supp.
1206, 1217 (D. Nev. 1975) (denying motion for a preliminary injunction,
permitting roundup of 400 wild horses to go forward, and noting the BLM
is given a “high degree of discretionary authority for the purposes of
protection, management, and control of wild free-roaming horses and
burros on the public lands”) (citation omitted).
  17
     Plaintiffs’ related argument that the BLM impermissibly removed
non-excess wild horses from the HMA when it temporarily gathered
nearly all of the animals fails because we hold that the initial temporary
roundup on the HMA did not constitute a “removal” under the Act.
       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 21

exclusively to” wild horse and burro welfare, see § 1332(c).
We need not determine whether the gather violated these
provisions of the Act because the record is bereft of an
essential foundational fact—designation of the Twin Peaks
HMA as a “range” by the Secretary pursuant to § 1333(a).18
According to the BLM’s summary of public comments for
the Gather Plan, the Twin Peaks HMA has not been
designated a “wild horse and burro range” by the Secretary,
nor have Plaintiffs presented any evidence suggesting that the
Twin Peaks HMA has been so designated. Therefore, any
requirements that might stem from the definition of “range”
in the Act do not apply to the Twin Peaks HMA.

    Fourth, Plaintiffs argue that the BLM violated the Act’s
mandate that the BLM manage horses and burros at a
“minimal feasible level” when the BLM “decided to chase
with helicopters and capture up to 100% of the wild horses
from the Twin Peaks HMA, remove[] about 80% [of the
herd], inject mares with immunocontraceptives, and
unnaturally skew the sex ratio.” The Act does provide that
“[a]ll management activities shall be at the minimal feasible
level . . . .” 16 U.S.C. § 1333(a). But Plaintiffs do not
adequately take into account the full statutory language,
which provides that “[a]ll management activities shall be at
the minimal feasible level and shall be carried out . . . in
order to protect the natural ecological balance of all wildlife
species which inhabit such lands . . . .” § 1333(a) (emphasis
added). Given BLM’s determination that the overpopulation


  18
     Agency regulations distinguish between “herd management areas,”
such as the Twin Peaks HMA, which need not be managed “principally
but not necessarily exclusively” for the welfare of wild horses and burros
and “wild horse and burro ranges” which must be so managed. See 43
C.F.R. § 4710.3-1, 4710.3-2.
22 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

of wild horses and burros threatened the natural ecological
balance on the HMA, it reasonably determined that the gather
was necessary to restore the AMLs and thereby protect the
HMA’s natural ecological balance.

    Moreover, the BLM had simultaneous duties not only “to
achieve and maintain a thriving natural ecological balance”
on the HMA, § 1333(a), but also to remove excess animals
“immediately” when the BLM determined “that an
overpopulation exist[ed].” § 1333(b)(2). Congress could not
have intended that the “minimal” management requirement
would force the BLM to ignore these other statutory
mandates. Given that this court must defer to the BLM’s
expertise under the APA, see Salmon River Concerned
Citizens v. Robertson, 32 F.3d 1346, 1356 (9th Cir. 1994), we
hold that the BLM reasonably interpreted its statutory
directive that management be at a “minimal feasible level”
when it decided to implement the Gather Plan in light of the
overpopulation at the time of the gather and the fact that
inaction would have led only to further detrimental
population increases.19

 19
   Given the rapid population growth, the district court also reasoned that
the BLM’s “efforts to slow reproduction . . . through
immunocontraceptives administered to released mares, and through a
skewed sex ratio of mares to stallions, is [] within the Act’s purview . . . .”
On appeal, Plaintiffs claim that Alternative B to the proposed gather plan,
which called for removing excess horses without fertility controls, would
have achieved the same result but with less impact. However, the EA
concluded that without population controls, the wild horse population
would grow at a faster rate and more animals would need to be removed
in the future to maintain the AMLs. As the district court correctly
reasoned, the BLM’s chosen action constitutes management at the
“minimal” feasible level because the gather was intended to reduce the
size and frequency of future gathers. In Defense of Animals, 909 F. Supp.
2d at 1194.
      IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 23

    Fifth, Plaintiffs incorrectly argue that the storage of
unadoptable excess wild horses at long-term holding facilities
owned by private contractors violated the Act. While the Act
does prohibit the BLM from relocating wild horses and
burros “to areas of the public lands where they do not
presently exist,” the Act does not prohibit such relocation to
private lands. 16 U.S.C. § 1339 (emphasis added). Because
nothing in the Act suggests that Congress intended to bar the
relocation of unadoptable horses to private lands for long-
term holding, we decline to read such a prohibition into the
Act.20

    Plaintiffs also contend that the privately-owned holding
facilities housing excess animals are “public lands” because
the Act defines “public lands” as “any lands administered by
the Secretary of the Interior through [the BLM].” 16 U.S.C.
§ 1332(e) (emphasis added). Plaintiffs claim the BLM

 20
    Moreover, as the D.C. Circuit has explained, “[s]ilence . . . may signal
permission rather than proscription,” and can suggest that Congress has
left a “question to agency discretion.” Catawba Cnty., N.C. v. EPA,
571 F.3d 20, 36 (D.C. Cir. 2009) (citations and internal quotation marks
omitted). Here, the BLM’s interpretation of the statute—that unadoptable
horses may be relocated to private lands for long-term holding—deserves
deference precisely because of the “gap” Congress has left in the statute.
See Schneider v. Chertoff, 450 F.3d 944, 960 (9th Cir. 2006). Congress
has barred the BLM from euthanizing healthy excess horses for which
there is no adoption demand pursuant to 16 U.S.C. § 1333(b)(2)(C) by
continually declining to appropriate funds for the destruction of these
animals. See, e.g., Pub. L. No. 111-88, 123 Stat. 2904, 2907 (2009)
(“Appropriations herein made shall not be available for the destruction of
healthy, unadopted, wild horses and burros in the care of the Bureau of
Land Management or its contractors.”). Thus, the BLM properly
determined that relocation of these animals to private facilities for long-
term holding is necessary because the Act simultaneously mandates that
the BLM remove “excess” horses immediately to maintain the established
AMLs. See 16 U.S.C. § 1333(b)(2).
24 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

“administers” these facilities by exercising oversight over the
lands, thereby converting the facilities into “public lands” to
which excess animals may not be transferred. This argument
fails. To “administer” means “to manage or conduct.”
Black’s Law Dictionary 65 (4th ed. 1968); Af–Cap, Inc. v.
Chevron Overseas (Congo) Ltd., 475 F.3d 1080, 1088 (9th
Cir. 2007) (“When determining the plain meaning of
language, we may consult dictionary definitions.”). Although
Plaintiffs cite a memo which suggests that two BLM officers
inspected the wild horses in one long-term holding facility by
counting the number of horses and observing their conditions,
such isolated references to the BLM’s oversight practices do
not establish that the BLM “manages or conducts” the land on
which the animals reside. On the contrary, the evidence
suggests that the private land-owners, not the BLM,
“administer” the lands because they effectuate the direct day-
to-day operations on the land.21

   We therefore hold that the BLM did not violate the Act by
implementing the 2010 gather on the Twin Peaks HMA.




 21
    While plaintiffs argue that transfer of the horses to long-term holding
facilities is contrary to Congress’s intent to allow these horses to remain
“wild and free-roaming,” the district court rebutted this point by noting
how “transfer to the private facilities . . . would appear to be far more
consistent with that [wild and free-roaming] behavior than the other
options for disposing of excess horses and burros contemplated by the
Act; namely, adoption, euthanasia, or commercial sale.” In Defense of
Animals, 909 F. Supp. 2d at 1194 n.7. Indeed, the record indicates that the
grassland pastures at the private facilities average approximately 10–11
acres per animal.
      IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 25

B. Plaintiffs’ NEPA claims

     Plaintiffs also appeal the district court’s holding that the
BLM did not violate the National Environmental Policy Act
(“NEPA”). In Defense of Animals, 909 F. Supp. 2d at 1198.
Plaintiffs contend that the BLM violated NEPA by declining
to prepare an environmental impact statement (“EIS”) and
failing to respond adequately to scientific evidence regarding
the adverse effects of the immunocontraceptive PZP.

    NEPA, 42 U.S.C. §§ 4321–4370, requires certain
procedural safeguards before an agency takes an action that
may significantly affect the environment. In particular,
NEPA requires federal agencies to prepare an EIS that
discusses the environmental ramifications for “major Federal
actions significantly affecting the quality of the human
environment.”22 42 U.S.C. § 4332(2)(C). To decide whether
an EIS is required because the agency’s action “significantly
affect[s] the quality of the human environment,” an agency
may first prepare an Environmental Assessment (“EA”),
which is a “concise public document” that must “[b]riefly
provide sufficient evidence and analysis for determining
whether to prepare an [EIS].” 40 C.F.R. § 1508.9(a)(1); Blue
Mountains Biodiversity Project v. Blackwood, 161 F.3d 1208,
1212 (9th Cir. 1998). When substantial questions are raised
as to whether a proposed project “may cause significant
degradation of some human environmental factor,” an EIS is

 22
   40 C.F.R. 1508.14 provides that the term “[h]uman environment shall
be interpreted comprehensively to include the natural and physical
environment and the relationship of people with that environment.” In the
context of wild horse gathers, this court has interpreted “human
environment” to encompass “not solely [the environmental impact] on the
rangelands, but [the environmental impact] on the horses as well.” Am.
Horse Protection Ass’n v. Andrus, 608 F.2d 811, 814 (9th Cir. 1979).
26 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

required. Pub. Citizen v. Nuclear Regulatory Comm’n,
573 F.3d 916, 929 (9th Cir. 2009) (quoting Ctr. for Biological
Diversity v. Nat’l Highway Traffic Safety Admin., 538 F.3d
1172, 1219 (9th Cir. 2008)).

    If an agency determines an EIS is not required, it must, as
did the BLM here, issue a Finding of No Significant Impact
(“FONSI”), briefly describing why the action “will not have
a significant effect on the human environment . . . .” 40
C.F.R. § 1508.13. In reviewing a decision not to prepare an
EIS under NEPA, the reviewing court “employ[s] an arbitrary
and capricious standard that requires us to determine whether
the agency has taken a ‘hard look’ at the consequences of its
actions, based [its decision] on a consideration of the relevant
factors, and provided a convincing statement of reasons to
explain why a project’s impacts are insignificant.” Envtl.
Prot. Info. Ctr. v. U.S. Forest Serv. (“EPIC”), 451 F.3d 1005,
1009 (9th Cir. 2006) (citation and internal quotation marks
omitted). In making this assessment, we must not “substitute
our judgment for that of the agency.” Okanogan Highlands
Alliance v. Williams, 236 F.3d 468, 473 (9th Cir. 2000).

    Agencies consider two broad factors to determine whether
an action may “significantly affect” the environment:
“context” and “intensity.” 40 C.F.R. § 1508.27; see also
Nat’l Parks & Conservation Ass’n v. Babbitt, 241 F.3d 722,
731 (9th Cir. 2001), abrogated on other grounds by
Monsanto Co. v. Geertson Seed Farms, 130 S. Ct. 2743, 2757
(2010). “Context simply delimits the scope of the agency’s
action, including the interests affected.” Babbit, 241 F.3d at
731. Intensity refers to the “severity of impact,” and the
regulations identify ten factors that agencies should consider
     IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 27

in evaluating intensity.            § 1508.27(b)(1)–(10) (listing
factors).23

    1. The BLM’s decision not to prepare an EIS

    The BLM’s 157-page Gather Plan EA, published in May
2010, reveals a detailed consideration of the then-current and
future status of riparian areas, cultural sites, native wildlife,
and wild horse and burro populations on the Twin Peaks
HMA. The EA based its conclusions on evaluations of the
condition and health of riparian sites between 1995 and 2009
performed by BLM specialists who could determine the
extent of damage caused by wild horses and burros, as
opposed to livestock and other factors. The report included
photos of affected sites and predictions of how the gather
would improve at least 80 riparian and cultural sites currently
damaged by wild horse trampling.

    23
        The “intensity” factors enumerated by § 1508.27(b) include:
(1) “Impacts that may be both beneficial and adverse”; (2) “The degree to
which the proposed action affects public health or safety”; (3) “Unique
characteristics of the geographic area such as proximity to historic or
cultural resources, park lands, prime farmlands, wetlands, wild and scenic
rivers, or ecologically critical areas”; (4) “The degree to which the effects
on the quality of the human environment are likely to be highly
controversial”; (5) “The degree to which the possible effects on the human
environment are highly uncertain or involve unique or unknown risks”;
(6) “The degree to which the action may establish a precedent for future
actions . . . ”; (7) “Whether the action is related to other actions with
individually insignificant but cumulatively significant impacts”; (8) “The
degree to which the action may adversely affect districts, sites, highways,
structures, or objects listed in or eligible for listing in the National
Register of Historic Places or may cause loss or destruction of significant
scientific, cultural, or historical resources”; (9) “The degree to which the
action may adversely affect an endangered or threatened species or its
habitat . . . ”; and (10) “Whether the action threatens a violation of
Federal, State, or local law . . . .”
28 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

     The EA also described the actions that would be taken to
ensure the helicopter gather process would not unnecessarily
stress the animals, and made clear that the capture methods,
traps, holding facilities, equipment, and administration of
immunocontraceptives would be in compliance with the
Standard Operating Procedures set out in the National Wild
Horses Gather Contract. The EA provided a thorough
analysis of numerous alternatives, including an alternative
that would not involve any fertility control measures, an
alternative that would use only fertility control measures, and
a no-action alternative. In short, the EA provided a detailed
analysis of the current environmental conditions on the HMA,
future projections for the environmental condition of the
HMA absent any action, an explanation of the BLM’s
preferred action in comparison to alternative actions that the
BLM could take, and the methodology and data upon which
its conclusions were based.

    Relying on this comprehensive analysis, the BLM’s
FONSI determined that the proposed gather would “not
significantly affect the quality of the human environment.”
The FONSI therefore concluded that the proposed gather was
“not a major federal action” for which an EIS would be
required. That conclusion was supported by a brief but
persuasive analysis of the ten intensity factors enumerated by
40 C.F.R. § 1508.27(b). See supra n.23. In particular, the
FONSI incorporated the 27-page environmental “effects”
analysis contained in the EA; noted that standard operating
procedures would be used to conduct the gather; emphasized
that the proposed action was not likely to affect public health
or safety because the Twin Peaks HMA “is located within a
very remote setting with little human habitation”; determined
that “cumulative effects expected would include continued
improvement of upland and riparian vegetation conditions”;
    IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 29

stated there are no threatened or endangered plants in the
surrounding area; and maintained that a cultural resources
survey of the HMA would occur before the gather and would
guide the choice of temporary trap sites. Plaintiffs challenge
the BLM’s decision not to issue an EIS, citing four of the
intensity factors from 40 C.F.R.§ 1508.27(b) for their
argument that substantial questions have been raised
regarding whether the gather may have a significant impact
on the wild horses and burros of the HMA.

    First, Plaintiffs claim the effects of the gather were
“highly controversial.” See 40 C.F.R. § 1508.27(b)(4) (listing
as an intensity factor “[t]he degree to which the effects on the
quality of the human environment are likely to be highly
controversial”). An action is “highly controversial” when “a
substantial dispute exists as to the size, nature, or effect of the
major federal action[.]” Humane Soc’y of the U.S. v. Locke,
626 F.3d 1040, 1057 (9th Cir. 2010). “A substantial dispute
exists when evidence . . . casts serious doubt upon the
reasonableness of an agency’s conclusions.” Babbitt,
241 F.3d at 736. Plaintiffs claim the gather was “highly
controversial” because of its “unprecedented” scope.
According to Plaintiffs, “[n]one of the previous roundups [on
the Twin Peaks HMA] included intensive manipulations of
the horses left on the range [such as injection of
immunocontraceptives into the mares and the skewing of the
stallion-to-mare ratio], and all of [the previous gathers]
rounded up a much smaller percentage of the overall
population [of wild horses and burros].”

    Plaintiffs are correct that the challenged gather was the
largest ever conducted on the Twin Peaks HMA, as the BLM
concedes. The BLM gathered approximately 1,639 wild
horses, almost double the number taken in the previous gather
30 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

of wild horses. Plaintiffs are also correct that some 2,300
public comments were submitted opposing the Gather Plan
EA.

    These considerations notwithstanding, if any opposition
to an agency’s proposed actions created a “substantial
dispute,” an EIS would seemingly always be required. Cf.
Native Ecosystems Council v. U.S. Forest Serv., 428 F.3d
1233, 1240 (9th Cir. 2005) (stating that the mere “existence
of opposition to a use” does not render a project “highly
controversial”). Even granting that this was the largest gather
ever conducted on the HMA, its foreseeable effect was
entirely precedented and non-controversial: the return of the
wild horse and burro populations to the long-established
AMLs. Indeed, the effects of gathers conducted on the Twin
Peaks HMA are well known to the BLM, as the BLM has
gathered animals on these lands since 1976 and gathered
approximately 4,000 wild horses on the HMA between 1998
and 2009. As for Plaintiffs’ contention regarding the
injection of immunocontraceptives into mares and the
skewing of the stallion-to-mare ratio, these practices have
been in use since at least 1992, and the comments on the EA
do not indicate that these practices are “highly controversial.”
Overall, given the EA’s clear and lengthy analysis regarding
the effects of the proposed gather, Plaintiffs have not
presented evidence that “casts serious doubt upon the
reasonableness of [the] agency’s conclusions,” and thus the
effects of the gather were not “highly controversial” at the
time the BLM issued its FONSI. See Locke, 626 F.3d at
1057.

     Second, Plaintiffs assert that the gather’s “possible effects
. . . on the wild horses and burros in this HMA are highly
uncertain and/or involve unique or unknown risks.” See 40
    IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 31

C.F.R. § 1508.27(b)(5) (listing as an intensity factor “[t]he
degree to which the possible effects on the human
environment are highly uncertain or involve unique or
unknown risks”). Plaintiffs cite two studies that claim to
demonstrate that the use of immunocontraceptives such as
PZP may have “potentially significant effects” on wild
horses. Plaintiffs also claim the gather’s combination of PZP
treatment with a large reduction in herd size and the skewing
of the herd’s sex ratio resulted in a high degree of uncertainty.

    This argument fails because “regulations do not anticipate
the need for an EIS anytime there is some uncertainty, but
only if the effects of the project are ‘highly’ uncertain.” Ctr.
for Biological Diversity v. Kempthorne, 588 F.3d 701, 712
(9th Cir. 2009) (citation and internal quotation marks
omitted). The effects of the gather were not “highly
uncertain” to the BLM, which, as noted above, has used PZP
to manage wild horse populations since 1992 and has made
adjustments to herd sex ratios in numerous gathers. And
Plaintiffs have submitted no evidence in support of their
assertion that the combination of these practices may actually
pose serious unknown risks.

    Plaintiffs’ strongest argument regarding the “highly
uncertain” intensity factor is their citation of two studies (a
study by Cooper and Larsen from 2006 and a study by Nunez
et al. from 2009) that discuss possible negative effects PZP
may have on the herd behavior and genetic diversity of wild
horse populations. However, these two articles are ultimately
insufficient to require a full EIS in a case like this where the
agency relied on other scientific findings to support its
conclusion that PZP would not have a significant negative
effect on the animals. See Marsh v. Oregon Natural Res.
Council, 490 U.S. 360, 378 (1989) (“When specialists express
32 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

conflicting views, an agency must have discretion to rely on
the reasonable opinions of its own qualified experts even if,
as an original matter, a court might find contrary views more
persuasive.”) Moreover, the district court correctly noted that
the studies cited by Plaintiffs found only “possible” effects of
PZP, and “therefore can be distinguished on that basis [from
the studies on which the BLM relied in its EA] since effects
that are only ‘possible’ do not represent true ‘dissenting’
views.” In Defense of Animals, 909 F. Supp. 2d at 1197.24
Some wild horse protection groups even commented on the
EA that the BLM should make greater use of contraceptive
treatments. This court has held that when an agency bases a
finding of no significant impact upon relevant and substantial
data, the fact that the record also contains some evidence
supporting a different scientific opinion does not necessarily
render the agency’s decision arbitrary and capricious. See
Greenpeace Action v. Franklin, 14 F.3d 1324, 1333 (9th Cir.
1992). We therefore decline to find that the effects of the
proposed gather were “highly uncertain.”

    Third, Plaintiffs claim the gather will “establish a
precedent for future actions with significant effects,” by
encouraging future roundups of this scope and intensity. See
40 C.F.R. § 1508.27(b)(6) (listing as an intensity factor “[t]he
degree to which the action may establish a precedent for
future actions with significant effects”). However, this
argument is foreclosed by Ninth Circuit law which holds that
“EAs are usually highly specific to the project and the locale,
thus creating no binding precedent.” Barnes v. U.S. Dep’t of


 24
    The district court also distinguished the studies cited by Plaintiffs on
the ground that those studies assessed the effects on wild horses of
repeated doses of PZP, whereas the Gather Plan only proposed to
administer a single dose. In Defense of Animals, 909 F. Supp. 2d at 1197.
       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 33

Transp., 655 F.3d 1124, 1140 (9th Cir. 2011) (citation
omitted). Thus, the BLM’s finding of no significant impact
in this case will not affect the BLM’s NEPA analysis in
future gathers.25

    We conclude that the BLM considered the relevant
intensity factors in making its finding of no significant impact
and “provided a convincing statement of reasons to explain
why [the] project’s impacts [were expected to be]
insignificant.” EPIC, 451 F.3d at 1009 (citation and internal
quotation marks omitted). Therefore, the BLM did not
violate NEPA when it decided not to issue an EIS.

       2. The BLM’s response to contrary scientific
          evidence

    Finally, Plaintiffs argue that the BLM failed to respond
adequately to opposing scientific views regarding potential
negative effects of the immunocontraceptive PZP, once again
citing the Cooper and Larsen (2006) and Nunez et al. (2009)
studies. In response to a comment on the EA that drew the
BLM’s attention to these studies, the BLM simply directed
readers to the sections of the EA that addressed fertility
controls. Those sections, in turn, provided citations to
various studies which supported the BLM’s conclusion that
PZP-treatment would not affect the horses’ hormone health,
the behavior of treated mares, pregnancies currently in
progress, or the health of offspring. Those sections also


  25
     Plaintiffs also cite a fourth intensity factor, claiming that the gather
“threatens a violation” of the Act. See 40 C.F.R. § 1508.27(b)(10) (listing
as an intensity factor “whether the action threatens a violation of Federal,
State, or local law”). This argument fails because, as discussed supra Part
A, the Gather Plan did not violate the Act.
34 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

determined that the effects of PZP were completely reversible
and that PZP could be easily administered in the field.
However, the BLM’s response to this comment, and the EA
itself, did not address why the BLM found the studies on
which it relied to be more persuasive than the Cooper and
Larsen, and Nunez et al. studies.

    Under NEPA, the panel must assess whether the BLM
“failed to address certain crucial factors, consideration of
which [is] essential to a truly informed decision whether or
not to prepare an EIS.” Found. for N. Am. Wild Sheep v. U.S.
Dep’t of Agric., 681 F.2d 1172, 1178 (9th Cir. 1982). This
issue presents a close question because, at first blush, it
appears that the BLM did indeed “fail[] to address” the two
studies which suggested that PZP may have detrimental
effects on herd behavior and genetic diversity. The BLM did
not discuss these studies, nor did the BLM explain why it
decided to rely on the studies mentioned in the EA as
opposed to the more recent studies cited in the comment.
This fact alone, however, does not automatically lead to a
NEPA violation.

    First, an agency’s failure to address a “certain crucial
factor” in deciding whether or not to prepare an EIS is not the
same as an agency’s failure to address and disclaim certain
evidence regarding that factor. Here, the “factor” is the effect
of PZP on wild horses. The BLM did consider that “factor”
by directing the reader to sections of the EA which addressed
fertility controls and provided citations to various studies
demonstrating the lack of negative effects resulting from the
administration of PZP. Thus, the BLM did address the
relevant factor. It simply did not write that the earlier studies
rebutted Plaintiffs’ speculations as to possible negative
effects of PZP. Second, one could just as easily argue that the
       IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 35

BLM did consider the studies because it responded to the
comment-at-issue by explicitly referencing the sections of the
EA that addressed fertility control. This suggests that the
BLM simply did not find the newer studies to be particularly
relevant or as scientifically accurate as the older studies on
which it relied.26 Cf. EPIC, 451 F.3d at 1017 (“When
specialists express conflicting views, we defer to the
informed discretion of the agency.”).

    Although a close question, the latter view is more
persuasive given the impracticality of a contrary holding that
would require agencies to address in detail the substance
conveyed in every single comment made on an EA to prove
that the agency “considered” the relevant factors. Indeed, this
court has stated that even for the more comprehensive EISs,
agencies “need not respond to every single scientific study or
comment.” Ecology Ctr. v. Castaneda, 574 F.3d 652, 668
(9th Cir. 2009). Moreover, “NEPA does not require federal
agencies to ‘assess . . . consider . . . [and] respond’ to public
comments on an EA to the same degree as it does for an EIS.”
 Cal. Trout v. F.E.R.C., 572 F.3d 1003, 1016 (9th Cir. 2009)
(emphasis added). Therefore, we hold that, despite the fact
that the BLM did not recite its reasons for relying on the
studies cited in the EA as opposed to the studies cited by the
comment, the BLM still performed the “hard look” required
by NEPA. See EPIC, 451 F.3d at 1009.


  26
    As discussed supra Part B.1, the district court distinguished the two
studies cited by the comment from the studies cited by the BLM on two
grounds. First, the studies cited by the comment found only “possible”
negative effects of PZP. Second, those studies assessed the effects on
wild horses of repeated doses of PZP, whereas the proposed gather only
administered a single dose. In Defense of Animals, 909 F. Supp. 2d at
1197.
36 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

                         Conclusion

    Ultimately, we conclude that the BLM acted within its
authority under the Wild Free-Roaming Horses and Burros
Act when it implemented the 2010 Gather Plan on the Twin
Peaks HMA. We also hold that the BLM’s decision not to
prepare an EIS was not arbitrary and capricious because the
BLM provided a convincing statement of reasons why the
gather’s environmental effects would not be significant.
Finally, we hold that the BLM did not act arbitrarily and
capriciously when it responded to comments highlighting the
possibility of scientific dissent regarding the administration
of the immunocontraceptive PZP. For those reasons, we
AFFIRM the decision of the district court granting summary
judgment to the Defendants.



RAWLINSON, Circuit Judge, dissenting:

   I respectfully dissent because I cannot agree that the
roundup of the wild horses by the Bureau of Land
Management (BLM) complied with the Wild Free Roaming
Horses and Burros Act (the Act).

    It is undisputed that Congress enacted this legislation to
protect wild horses and burros “from capture, branding,
harassment or death” and to do so while the horses and burros
are “considered in the area where presently found, as an
integral part of the natural system of the public lands.”
16 U.S.C. § 1331. Congress made an express finding that
“wild free-roaming horses and burros are living symbols of
the historic and pioneer spirit of the West; that they
contribute to the diversity of life forms within the Nation and
    IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 37

enrich the lives of the American people.” Id. Congress was
concerned that “these horses and burros are fast disappearing
from the American scene.” Id. From these explicit
Congressional expressions, we can discern four important
legislative purposes: (1) acknowledgment of the importance
of wild horses as “living symbols” of our Western heritage;
(2) recognition that these treasured symbols “are fast
disappearing from the American scene;” (3) articulation of
Congressional policy to protect wild horses “from capture,
branding, harassment or death”; and (4) designation of the
area where the horses are “presently found” to accomplish the
protection of the wild horses. Id.

    With these express Congressional purposes in mind, I
now consider 16 U.S.C. § 1333, the specific provision under
which the BLM effectuated removal of the wild horses from
their home on the range.

    Pursuant to 16 U.S.C. § 1333(a), the Secretary of the
Interior is directed to first protect and then to manage the wild
horse population. Wild horses and burros are considered
“components of the public lands” who are to be managed “at
the minimal feasible level.” 16 U.S.C. § 1333(a).

    Section 1333(b) authorizes the Secretary to remove only
“excess animals.” If an overpopulation of wild horses exists,
the Act mandates that any removal take place “in the
following order and priority, until all excess animals have
been removed”:

           (A) The Secretary shall order old, sick, or
        lame animals to be destroyed in the most
        humane manner possible;
38 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

          (B) The Secretary shall cause such
       number of additional excess wild free-
       roaming horses and burros to be humanely
       captured and removed [for adoption] . . . ; and

           (C) The Secretary shall cause additional
       excess wild free-roaming horses and burros
       for which an adoption demand . . . does not
       exist to be destroyed in the most humane and
       cost efficient manner possible. 16 U.S.C.
       § 1333(b)(1)–(2).

     The Act couldn’t be clearer. Congress, has specifically
listed the order in which excess wild horses are to be
removed. First, and before any horses are captured, “old, sick
or lame animals” are “to be destroyed.” Id. § 1333(2)(A).
Only after the first listed priority has been completed does the
Act authorize “additional excess wild free-roaming horses
and burros to be humanely captured and removed” for
adoption. Id. at § 1333(2)(B). Finally, any remaining
“additional excess wild free-roaming horses and burros” for
which no adoption demand exists may be destroyed. Id. at
§ 1333(2)(C).

    There is absolutely no textual support in the Act for the
Secretary to capture the entire herd of wild horses, excess and
non-excess alike, in total disregard of the explicit priority
articulated in the Act. In addition, it cannot be gainsaid that
the wholesale capture of the wild horse herd is the complete
antithesis of the “minimal feasible level” of management
mandated by the Act. 16 U.S.C. § 1333(a).

   The majority overlooks this flagrant lack of compliance
with the Act by adopting the BLM’s argument that the
    IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 39

“gathering” of animals is not a removal governed by the
provisions of § 1333(b)(2). Majority Opinion, p.18–19.
However, if the BLM is not managing the excess animals
pursuant to § 1333(b)(2), no other portion of the Act
authorizes capture of excess horses for the purpose of
removal. And absolutely nothing in the Act authorizes the
capture of non-excess horses. The definition of removal
adopted by the BLM and parroted by the majority completely
ignores the Act’s admonition against capturing or harassing
the wild horses, and its instruction to manage the horses
where they are found, as part of the public lands. See
16 U.S.C. § 1331. As stated, the BLM’s interpretation allows
the capture of excess and non-excess horses alike, which was
clearly not the intent of the carefully crafted legislation
directed toward the capture and removal of excess horses
only.

    If, as the BLM argues and the majority accepts, its
“gather” were not contemplated by § 1333(b)(2), Congress
would not have carefully crafted the priority provisions of the
Act. It is only after old, sick or lame animals are destroyed
that the Act provides for additional excess wild horses to be
captured. See § 1333(b)(2)(A)–(B). The BLM completely
circumvented this statutory mandate and violated the express
purpose of Congress to protect the wild horses from capture
and/or harassment. See 16 U.S.C. § 1331. When an agency’s
interpretation of a statute is totally inconsistent with the
express purpose of the statute, that interpretation is null and
void. See Int’l Longshoremen’s & Warehousemen’s Union v.
Meese, 891 F.2d 1374, 1383 (9th Cir. 1989), as amended
(“This court recognizes that ordinarily an agency’s
interpretation is entitled to deference, however, courts must
reject an administrative construction of a statute that is
40 IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR

inconsistent with the statutory mandate or that frustrates
Congress’ purpose. . . .”) (citation omitted).

    Unlike the majority, I am not persuaded by the rationale
in the district court decision of In Defense of Animals v.
Salazar, 675 F.Supp. 2d 89 (D. D.C. 2009). As an initial
matter, that case involved the denial of a preliminary
injunction and rested on a balancing of the preliminary
injunction factors rather than a definitive legal ruling on the
merits. See id. at 95–96 (discussing likelihood of success on
the merits). More importantly, although the court purported
to consider the purpose of the statute, see id., it completely
ignored the actual text of the statute defining its purpose as to
protect the wild horses from capture or harassment and to do
so where the horses were “presently found.” 16 U.S.C.
§ 1331.

     The record in this case reflects that the BLM has
previously identified injured wild horses on the range without
first capturing them. Therefore, no legitimate basis existed
for cavalierly chasing the horses with helicopters for miles
before capturing them, including horses who were admittedly
non-excess.

    Under the Administrative Procedure Act, an agency
abuses its discretion when its actions are contrary to law. See
Organized Village of Kake v. U.S. Dept. of Agric., No. 11-
35517, – F.3d –, 2014 WL 1229762 (9th Cir. Mar. 26, 2014)
(articulating that “[a]n agency’s action is arbitrary and
capricious if . . . the agency’s decision is contrary to the
governing law”) (citation omitted). In my view, the BLM
actions completely flouted the Wild Free-Roaming Horses
and Burros Act and thereby abused its discretion. See id.
Because the BLM’s interpretation and application of the Act
    IN DEFENSE OF ANIMALS V. DEP’T OF THE INTERIOR 41

ignored the text, intent and purpose of the statute, absolutely
no deference was owed to the agency action taken in reliance
on that interpretation.         See Int’l Longshoremen’s &
Warehousemen’s Union, 891 F.2d at 1383; see also Dyack v.
Commonwealth of N. Mariana Islands, 317 F.3d 1030, 1036
(9th Cir. 2003) (“Although we generally defer to an agency’s
construction of a statute it administers, we will not do so
where the agency’s interpretation is contrary to the legislative
intent. . . .”) (citation omitted).

   I respectfully dissent.
