Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca9-14-35445/USCOURTS-ca9-14-35445-0/pdf.json

Parties Involved:
American Sheep Industry Association
Appellant
Carlson Company, Inc.
Appellant
Colorado Wool Growers Association
Appellant
Hells Canyon Preservation Council
Appellee
Idaho Wool Growers Association
Appellant
Keith Lannom
Appellee
Public Lands Council
Appellant
Shirts Brothers Sheep
Appellant
The Wilderness Society
Appellee
Tom Tidwell
Appellee
United States Forest Service
Appellee
Tom Vilsack
Appellee
Western Watersheds Project
Appellee
Wyoming Wool Growers Association
Appellant

Document Text:

FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

IDAHO WOOL GROWERS

ASSOCIATION; AMERICAN SHEEP

INDUSTRY ASSOCIATION; PUBLIC

LANDS COUNCIL; WYOMING WOOL

GROWERS ASSOCIATION; CARLSON

COMPANY, INC.; SHIRTS BROTHERS

SHEEP; COLORADO WOOL GROWERS

ASSOCIATION,

Plaintiffs-Appellants,

 v.

TOM VILSACK, in his official

capacity as the Secretary of the U.S.

Department of Agriculture; TOM

TIDWELL, in his official capacity as

the Chief of the U.S. Forest Service;

KEITH LANNOM, in his official

capacity as the Forest Supervisor of

the Payette National Forest; UNITED

STATES FOREST SERVICE,

Defendants-Appellees,

THE WILDERNESS SOCIETY;

WESTERN WATERSHEDS PROJECT;

HELLS CANYON PRESERVATION

COUNCIL,

Intervenor-Defendants–Appellees.

No. 14-35445

D.C. No. 

1:12-cv-00469-

BLW

OPINION

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2 IDAHO WOOL GROWERS ASS’N V. VILSACK

Appeal from the United States District Court

for the District of Idaho

A. Wallace Tashima, District Judge, Presiding*

Argued and Submitted 

November 2, 2015—Portland, Oregon

Filed March 2, 2016

Before: Raymond C. Fisher, Marsha S. Berzon, and

Paul J. Watford, Circuit Judges.

Opinion by Judge Berzon

SUMMARY**

Environmental Law

The panel affirmed the district court’s summary judgment

in favor of the United States Forest Service in an action

challenging the Forest Service’s decision, made in response

to concerns regarding disease transmission to

immunologically vulnerable bighorn sheep, to close to

domestic sheep grazing approximately 70% of allotments on

* A. Wallace Tashima, Circuit Judge, for the Ninth Circuit Court of

Appeals, sitting in the United States District Court, for the District of

Idaho, by designation.

** This summary constitutes no part of the opinion of the court. It has

been prepared by court staff for the convenience of the reader.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 3

which grazing had been permitted in the Payette National

Forest in Idaho.

The panel held that, pursuant to the National

Environmental PolicyAct environmental review process, any

error by the Forest Service in failing to consult the

Agricultural Research Service, a federal agency within the

U.S. Department of Agriculture, before preparing the final

supplemental impact statement and Record of Decision, was

harmless. The panel held that because the lack of

consultation did not prevent the Forest Service or the public

from considering information about the uncertainties in

transmission of disease from domestic to bighorn sheep, such

as the Agricultural Research Service would have offered, and

because information about the precise mechanisms of such

transmission was not a basis of the Forest Service’s decision,

no prejudice resulted from the lack of consultation. 

The panel also held that the Forest Service did not

otherwise act arbitrarily or capriciously or abuse its

discretion. Specifically, the panel held that the Forest Service

did not act arbitrarily or capriciously or abuse its discretion

by declining to supplement the final supplemental impact

statement. The panel also held that the Forest Service did not

act arbitrarily or capriciously or abuse its discretion in its

modeling used to analyze bighorn sheep home ranges and

movement, and the potential impacts of various management

alternatives.

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4 IDAHO WOOL GROWERS ASS’N V. VILSACK

COUNSEL

William G. Myers III (argued) and Murray D. Feldman,

Holland & Hart LLP, Boise, Idaho, for Plaintiffs-Appellants.

Robert J. Lundman (argued) and David B. Glazer,

Environment &Natural ResourcesDivision,U.S. Department

of Justice, Washington, D.C.; Sam Hirsch, Acting Assistant

Attorney General, U.S. Department of Justice, Washington,

D.C.; Heather Hinton-Taylor, Office of the General Counsel,

U.S. Department of Agriculture, Washington, D.C., for

Defendants-Appellees.

Lauren M. Rule (argued), Advocates for the West, Portland

Oregon; Jennifer R. Schemm, La Grande, Oregon, for

Intervenor-Defendants–Appellees. 

OPINION

BERZON, Circuit Judge:

Between the late 1800s and the early 1900s, the number

of bighorn sheep in North America declined dramatically,

falling from a high of 1.5 to 2 million individuals to

approximately 10% of that number. Scientists have generally

attributed the decline to over-harvesting, habitat loss,

competition for food, and disease transmission from domestic

sheep.

In response to concerns regarding disease transmission to

immunologically vulnerable bighorn sheep, the Chief of the

U.S. Forest Service ordered further analysis of the effects of

grazing domestic sheep in the Payette National Forest of

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IDAHO WOOL GROWERS ASS’N V. VILSACK 5

west-central Idaho (“Payette”). In response, the Forest

Service prepared a draft supplemental environmental impact

statement (“DSEIS”), an update to the DSEIS, and,

eventually, a final supplemental environmental impact

statement (“FSEIS”) and Record of Decision (“ROD”). 

Concluding that there is a significant risk of fatal disease to

the small and insular populations of bighorn sheep in the

Payette, the Forest Service decided in the ROD to close to

domestic sheep grazing approximately 70% of the allotments

on which grazing had been permitted.

The Idaho Wool Growers Association, other state and

national trade associations, and two sheep ranchers

(collectively, “Wool Growers”) challenged the Forest

Service’s decision, objecting to the Forest Service’s (1)

failure to consult the Agricultural Research Service (“ARS”),

a federal agency within the U.S. Department of Agriculture,

before preparing the FSEIS and ROD; (2) failure to

supplement the FSEIS and ROD in light of the publication in

2010 of a certain study of the transmission of disease from

domestic to bighorn sheep, the “Lawrence study”; and (3)

choice and use of particular models to evaluate the risk of

contact between domestic and bighorn sheep and the effects

of disease transmission from domestic to bighorn sheep. The

district court entered summary judgment in favor of the

Forest Service. Wool Growers appealed.

We conclude that any error in failing to consult ARS was

harmless. As the Forest Service did not otherwise act

arbitrarily or capriciously or abuse its discretion, we affirm.

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6 IDAHO WOOL GROWERS ASS’N V. VILSACK

I.

A. Background

Bighorn sheep are currently found in two populations in

the Payette—one in Hells Canyon and the other in the Salmon

River Mountains. In approximately 1870, major die-offs of

bighorn sheep began to occur in the Salmon River Mountains. 

The die-offs roughly coincided with the onset of wide-spread

grazing of domestic sheep in the Payette.

Over the years, the Payette’s bighorn populations have

continued to experience periodic “large-scale, rapid, all-age

die-offs.” FSEIS xx; see also ROD 6–7. Since 1981, despite

efforts at transplanting sheep from elsewhere, the total

population in the Payette has decreased by 47%. Although at

one time more than 10,000 bighorn sheep lived in Hells

Canyon and the surroundingmountains, “theywere extirpated

by the mid-1940s.” ROD 6. Between 1971 and 2004, 474

bighorn sheep were transplanted into Hells Canyon. Seven

die-offs in the Hells Canyon population have been reported

since 1971. At the time the FSEIS was written, that

population numbered 850 sheep.

The Salmon River population was never extirpated. 

According to surveys in 2001, 2003, and 2004, that

population numbers roughly 700 sheep.

B. The NEPA Environmental Review Process

The administrative process underlying this appeal began

in 2003, when the Forest Service, pursuant to the National

Environmental Policy Act (“NEPA”), issued the Southwest

Idaho Ecogroup Land and Resource Management Plans Final

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IDAHO WOOL GROWERS ASS’N V. VILSACK 7

Environmental Impact Statement and Record of Decision

(“EIS”), which revised the 1988 Payette National Forest Land

and Resource Management Plan. The EIS was appealed,

appellants urging that the EIS “violated the [National Forest

Management Act] and Hells Canyon National Recreation

Area (HCNRA) Act on the Payette National Forest by

providing for grazing of domestic sheep within or near the

range of bighorn sheep, thus threatening the viability of

bighorn sheep though [sic] disease transmission.” ROD 1. In

March 2005, the Chief of the Forest Service agreed that the

EIS “did not adequately address viability [of bighorn sheep

populations in the Payette] or the potential for disease

transmission.” Id. The Chief therefore rejected the EIS’s

analysis. 

The Chief then “instructed the Regional Forester to

reanalyze the potential impacts of domestic sheep grazing on

bighorn sheep viability on the Payette National Forest to

ensure habitat is available to support a viable population of

bighorn sheep.” ROD 1. The Chief’s decision reflected

general concerns regarding disease transmission—in

particular, the spread of various strains of pneumonia-causing

or -contributing bacteria—from domestic to bighorn sheep, as

confirmed by anecdotal evidence and a multitude of studies.

There is uncertainty regarding the particular mechanics of

disease transmission, and the evidence of transmission is

largely circumstantial. Pneumonia-causing bacteria are

commonly found in domestic sheep, with the worst outbreaks

killing 2.5% of domestic sheep in a herd. The impact of

pneumonia on bighorn sheep is considerably more

catastrophic. Episodic pneumonia outbreaks appear to be the

current limiting factor in bighorn sheep abundance and

distribution, both because large-scale die-offs caused by

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8 IDAHO WOOL GROWERS ASS’N V. VILSACK

pneumonia kill most or all of a given population, and because

female bighorns who survive die-offs experience low

reproduction and high lamb mortality rates for years

following an outbreak. Consequently, a number of state and

federal agencies with jurisdiction over bighorn sheep have

expressed concern and modified their management plans to

address disease transmission from domestic to wild sheep. 

ROD 6; see, e.g., John Beecham et al., Rocky Mountain

Bighorn Sheep (Ovis Canadensis): A Technical Conservation

Assessment, Feb. 12, 2007; Timothy Schommer & Melanie

Woolever, A Review of Disease Related Conflicts Between

Domestic Sheep and Goats and Bighorn Sheep, 2008;

Montana Department of Fish, Wildlife and Parks, Montana

Bighorn Sheep Conservation Strategy, Draft, August 2009;

Idaho Department of Fish & Game, Draft Bighorn Sheep

Management Plan, May 2010. As the FSEIS explained,

“[s]cientists from both sides of the issue . . . recommend that

the species be kept separate until the disease transmission

science is better understood.” ROD 11.

In September 2008, the Forest Service released the

DSEIS, which “proposed to modify, delete, and add to the

current Forest Plan direction in response to the Chief’s

instructions.” ROD 1. The DSEIS precipitated over 14,000

public comments. 

In 2009, because of declining bighorn sheep numbers, the

Forest Service designated bighorn sheep a sensitive species

in the Intermountain Region, which includes the Payette. 

Under that designation, the objectives of bighorn

management “are to prevent listing under the Endangered

Species Act (ESA), avoid or minimize impact to [the]

species[,] whose viability has been identified as a concern,

maintain viable populations of [the] species, and to develop

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IDAHO WOOL GROWERS ASS’N V. VILSACK 9

and implement management objectives for [the species’]

populations and habitat.” ROD 8. 

The Forest Service released an update to the DSEIS in

January 2010, which “provided interested stakeholders and

the public an opportunity to review and comment on

improved analyses and alternatives.” ROD 1. In the update,

the Forest Service responded to criticisms of the DSEIS’s

qualitative analysis by providing a quantitative analysis. See

FSEIS xvii; e.g., A-85. That analysis used modeling to study

the potential risks and effects of contact and disease

transmission. More than 11,000 comments on the update to

the DSEIS were submitted.

In July 2010, the Forest Service completed and released

the FSEIS and ROD. To analyze the effects of various

alternative plans on the Payette’s bighorn sheep, the Forest

Service used three models developed in conjunction with

researchers at the University of California, Davis Center for

Animal Disease Modeling and Surveillance. The models—

called the source habitat, risk of contact, and disease

models—incorporated telemetric location data, including

more than 54,000 data points collected in the Payette over the

course of twelve years from over 400 radio-collared bighorn

sheep. Even with the use of these models, the Forest Service

recognized, “[d]etermining the probability that a bighorn

sheep will reach an occupied [domestic sheep grazing]

allotment [in the Payette] and that contact between the

species will result in disease transmission is problematic,”

and “there is . . . essentially no research that would allow []

estimation” of the likelihood of contact causing disease

transmission. ROD 12. To account for that difficulty, the

Forest Service ran the disease model using a range of

probabilities of contact resulting in disease transmission—

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10 IDAHO WOOL GROWERS ASS’N V. VILSACK

5%, 10%, 25%, 50%, 75%, and 100%. This approach

allowed the Forest Service to assess the effects of various

management alternatives on bighorn sheep subpopulations

despite its inability to estimate accurately the degree of risk

of disease-conveying contact.

After applying the models, the Forest Service selected one

of the alternatives analyzed in the FSEIS, Alternative 7O. 

Alternative 7O would result in the termination of domestic

sheep grazing on approximately 69,000 acres in the Payette,

with implementation to occur over three years. The models

showed that this alternative reduced the risk of extirpation of

all but one of the bighorn subpopulations to low-to-moderate

at the 5% transmission level; the models predicted a 100%

likelihood of extirpation of the Sheep Mountain

subpopulation at all transmission levels, due to that

subpopulation’s demographics and proximity to domestic

sheep grazing allotments. At the higher transmission levels,

the probabilities of extirpation under Alternative 7O ranged

from 4% to 76%. Ultimately, the Forest Service found that

large distances between domestic and bighorn sheep are

necessary to assure protection of bighorns from disease, as

bighorn sheep travel long distances across rugged terrain;

domestic sheep are known to stray from their herds,

remaining on allotments at unpermitted times; and bighorn

and domestic sheep are attracted to each other and seek out

each other’s company.

The FSEIS incorporated findings from the thenunpublished Lawrence study, the first experiment to

demonstrate directly that transmission of bacteria from

domestic to bighorn sheep is implicated in causing

pneumonia in bighorn sheep. The study’s authors extracted

bacteria from domestic sheep, genetically modified the

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IDAHO WOOL GROWERS ASS’N V. VILSACK 11

bacteria to be antibiotic resistant and to radioactively

fluoresce (that is, give off light). The domestic sheep were

then inoculated with the modified bacteria. The domestic

sheep were initially placed in pens separated by ten meters

from pens of bighorn sheep. Later, they were moved so that

they were separated only by a fence. Still later, all the sheep

were commingled in a single pen.

By the end of the study, three of the four bighorn sheep

had contracted pneumonia and died, and the fourth was

euthanized after displaying telltale and severe signs of

pneumonia. Post-mortem examinations of the bighorn sheep

showed that they carried the radioactively-labeled, antibioticresistant bacteria with which only the domestic sheep had

been inoculated.

C. This Litigation

Wool Growers appealed the ROD and FSEIS to the

Intermountain Regional Forester. During the appeal process,

Dr. Donald Patrick Knowles, a co-author of the Lawrence

study and a research scientist within ARS, submitted a letter

discussing his interpretation of the study’s results (“Letter”). 

Dr. Knowles maintained that (1) the study did not prove that

fence-line contact between domestic and bighorn sheep

resulted in transmission of pneumonia-causing bacteria

between the species; (2) transmission of a disease-causing

organism, as well as the mechanisms of disease, are complex

processes; and (3) “transmission of an organism doesn’t

necessarily lead to disease.” Letter 1–2. The Regional

Forester, having considered Dr. Knowles’ input, denied Wool

Growers’ appeal.

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12 IDAHO WOOL GROWERS ASS’N V. VILSACK

Wool Growers then filed a complaint for declaratory and

injunctive relief in the district court, challenging the Forest

Service’s decision. The court granted Intervenors, a group of

environmental organizations, leave to enter the action as

defendants. Wool Growers moved to expand the record

pursuant to Asarco, Inc. v. U.S. EPA, 616 F.2d 1153 (9th Cir.

1980).

1 The district court granted the motion, permitting the

parties to submit expert declarations in support of their crossmotions for summary judgment. After a hearing, the district

court entered summary judgment in favor of the Forest

Service and Intervenors and dismissed the action.

Wool Growers timely appealed the district court’s

decision. On appeal, Wool Growers challenges three aspects

of the Forest Service’s decision under NEPA: its (1) failure

to consult ARS prior to completing the FSEIS; (2) failure to

supplement the FSEIS; and (3) choice and use of models.

II.

NEPA is a purely procedural statute; it does not impose

any substantive requirements on an agency undertaking

environmental review. Lands Council v. McNair, 537 F.3d

981, 1000 (9th Cir. 2008) (en banc), overruled on other

grounds by Winter v. Nat. Res. Def. Council, Inc., 555 U.S. 7,

20 (2008). Rather, “NEPA aims to make certain that the

agency will have available, and will carefully consider,

detailed information concerning significant environmental

impacts, and that the relevant information will be made

available to the larger public audience.” Id. (citation and

1 Under Asarco, an administrative record can be expanded upon review

by a federal court to explain what’s already in the record but not to add

substantive evidence. 616 F.2d at 1159–60.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 13

alterations omitted). Accordingly, federal agencies must

“take a ‘hard look’ at the environmental consequences of

their actions by preparing an EIS for each ‘major Federal

action significantly affecting the quality of the human

environment.’” Id. at 1000–01 (alteration omitted) (quoting

42 U.S.C. § 4332(2)(C)). An EIS “must ‘provide [a] full and

fair discussion of significant environmental impacts’ so as to

‘inform decisionmakers and the public of the reasonable

alternatives which would avoid or minimize adverse impacts

or enhance the quality of the human environment.’” Id. at

1001 (quoting 40 C.F.R. § 1502.1).

Under NEPA and the Administrative Procedure Act

(“APA”), our review is limited to determining whether the

Forest Service’s analysis was “arbitrary, capricious, an abuse

of discretion, or otherwise not in accordance with law.” Id.

at 987 (quoting 5 U.S.C. § 706(2)(A)). We conclude that

although the Forest Service may have acted contrary to

NEPA in one respect, any such error was harmless. The

Forest Service did not otherwise act arbitrarily or

capriciously, nor did it abuse its discretion.

A. Consultation

1. Duty to consult

NEPA imposes on federal agencies conducting

environmental review a duty to consult with certain other

agencies. “Prior to making any detailed statement, the

responsible Federal official shall consult with and obtain the

comments of any Federal agency which has jurisdiction by

law or special expertise with respect to any environmental

impact involved [in the proposed action].” 42 U.S.C.

§ 4332(2)(C). Further, to promote NEPA’s policies of public

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14 IDAHO WOOL GROWERS ASS’N V. VILSACK

participation and informed decisionmaking, copies of the EIS

and comments thereon from other agencies “shall accompany

the proposal through the existing agency review processes.” 

Id.

The regulations implementing these provisions state that

“[a]fter preparing a draft environmental impact statement and

before preparing a final environmental impact statement the

agency shall . . . [o]btain the comments of any Federal agency

which has jurisdiction by law or special expertise with respect

to any environmental impact involved . . . .” 40 C.F.R.

§ 1503.1(a)(1); see also id. § 1500.1(b) (“Accurate scientific

analysis, expert agency comments, and public scrutiny are

essential to implementing NEPA.” (emphasis added)). 

“Special expertise” is defined as “statutory responsibility,

agency mission, or related program experience.” Id.

§ 1508.26. Under the statute and its implementing

regulations, the Forest Service may have had a duty to consult

with ARS before issuing the FSEIS. 

The pivotal question is whether ARS has “special

expertise” concerning one significant aspect of the proposed

decision, the mechanics of pathogen transmission in domestic

sheep.2 Wool Growers argues that it does. They note, for

example, that 7 C.F.R. § 2.65 delegates to ARS, among other

matters, the authority to “[c]onduct research concerning

domestic animals and poultry, their protection and use, [and]

the causes of contagious, infectious, and communicable

diseases.” Also, ARS’s mission statement proclaims: “ARS

2 Because we decide that any consultation error was harmless, see

section II.A.2., infra, we do not address the Forest Service’s argument that

the “special expertise” question does not apply to Dr. Knowles as an

individual.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 15

conducts research to develop and transfer solutions to

agricultural problems of high national priority and provide

information access and dissemination to . . . enhance the

natural resource base and the environment . . . .” U.S.

Department of Agriculture, Agricultural Research

Service, ARS: About US, http://www.ars.usda.gov/aboutus/

aboutus.htm.

The Forest Service argues, in response, that it had no duty

to consult with ARS because that agency has no expertise in

wildlife management. Although ARS’s expertise does center

on domestic, not wild, animals, the development within and

movement of pathogens in domestic sheep is of some

relevance to concerns regarding disease transmission to

bighorn sheep. The Forest Service’s assessment of the

pertinence of that expertise may be too narrow an

interpretation of its consultation duty under NEPA. And the

language establishing NEPA’s consultation requirement is

expansive. It mandates consultation with any federal agency

that has “special expertise with respect to any environmental

impact involved.” 42 U.S.C. § 4332(2)(C) (emphasis added). 

See also 40 C.F.R. § 1503.1(a)(1) (“[T]he agency shall . . .

[o]btain the comments of any Federal agency which has

jurisdiction by law or special expertise with respect to any

environmental impact involved . . . .” (emphasis added)).

Further, Warm Springs Dam Task Force v. Gribble

suggests that for the consultation requirement to apply, the

particular expertise of an agency does not have to encompass

the proposed project as a whole or the issue the proposed

project was designed to address. Rather, the expertise need

relate only to one of the project’s anticipated environmental

effects. See 621 F.2d 1017, 1020–21 (9th Cir. 1980) (per

curiam).

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In the end, we need not resolve in this case the precise

parameters of the consultation requirement, or whether it

extended to ARS on the record before us. Any violation of

the consultation duty that occurred here, we are persuaded,

was harmless.

2. Prejudice

The APA directs us to take “due account . . . of the rule of

prejudicial error.” 5 U.S.C. § 706; see Nevada v. Dep’t of

Energy, 457 F.3d 78, 90 (D.C. Cir. 2006). Accordingly, we

consider whether the Forest Service’s failure to consult was

harmless. See Warm Springs, 621 F.2d at 1022–23. The

harmless-error analysis asks whether the failure to consult

materially impeded NEPA’s goals—that is, whether the error

caused the agency not to be fully aware of the environmental

consequences of the proposed action, thereby precluding

informed decisionmaking and public participation, or

otherwise materially affected the substance of the agency’s

decision. See Tucson Herpetological Soc. v. Salazar, 566

F.3d 870, 880 (9th Cir. 2009).

Here, Wool Growers contends that, had consultation

occurred, ARS and Dr. Knowles would have conveyed to the

Forest Service information regarding the uncertainties of

disease transmission mechanisms from domestic sheep and

other contributors to bighorn disease. It is fair to assume Dr.

Knowles would have offered this information—he did offer

it to the Forest Service, both in his letter on appeal to the

Forest Supervisor, as well as in his declarations in the

expanded record before the district court. But, as reflected in

the FSEIS, such information had already been amply

communicated, and the Forest Service and the public already

had considered it. 

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IDAHO WOOL GROWERS ASS’N V. VILSACK 17

For example, the FSEIS acknowledged: 

Some of these contentions [challenging the

link between disease in domestic sheep and

disease in bighorn sheep] are accurate. We do

not understand all of themechanisms involved

in potential disease transmission between the

species. . . . Arguably, much of the evidence

is circumstantial; however, the compilation of

cases throughout several decades does

contribute to an increasing body of evidence

that overwhelmingly demonstrates bighorn

sheep near domestic sheep are at risk for

disease transmission, even though “contact”

may not have actually been observed.

FSEIS xxi. The FSEIS also specifically acknowledged

comments by “scientists and others, primarily from

agricultural disciplines,” regarding the effect of stressors on

bighorn sheep disease, as well as uncertainties regarding

disease transmission. Id. at 3-12–3-14. And in the ROD, the

Forest Supervisor took those views and comments into

consideration, stating: “Some scientists and others, primarily

from agricultural disciplines, contend that disease

transmission between bighorn sheep and domestic sheep is

not a relevant factor in bighorn sheep distribution and

population declines in the wildland environment. I have

taken these arguments into consideration while making my

decision.” ROD 11.

Nor did these concerns escape public comment. The

public provided extensive comments showing awareness of

these considerations, including the comments that: “The

FSEIS should be particularly thorough when assessing the

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18 IDAHO WOOL GROWERS ASS’N V. VILSACK

literature on the causal relationship of disease transmission

between domestic sheep and bighorn sheep,” FSEIS A-81;

“[e]vidence linking disease outbreaks to domestic sheep is

inconclusive,” “[s]tudies documenting disease transmission

between the two species have been done in controlled

environments,” and “[s]tress could be a precursor to the onset

of sickness”, id. at A-87; and “[t]he Forest Service should

disclose plans for reduction or elimination of stressors, such

as bad weather or lack of nutrition, that can predispose

bighorn sheep to disease or exacerbate risk of mortality,” id.

at A-186. 

In Warm Springs, we found no prejudice arising from the

Army Corps of Engineers’ failure to consult the U.S.

Geological Survey because the Corps subsequently

considered the study that consultation would have revealed. 

See 621 F.2d at 1023. Similarly here, the Forest Service’s

failure to consult did not prejudice its review process. The

Forest Service took into account essentially the same

comments—arguments from “scientists and others, primarily

from agricultural disciplines” contesting the inference that

domestic sheep can and do transmit disease to wild bighorn

sheep—thatARS, through Dr. Knowles, would have provided

by formally consulting with the Forest Service during the

environmental review process.

The Forest Service’s failure to consult ARS is immaterial

for another reason as well. The precise mechanisms of

disease transmission did not affect the Forest Service’s

decision. As the FSEIS states: “The exact means by which

the disease is transferred [from domestic to bighorn sheep] is

beyond the scope of this analysis and should be conducted by

qualified researchers.” FSEIS A-187. The FSEIS’s

conclusion was that the scientific consensus is that disease

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IDAHO WOOL GROWERS ASS’N V. VILSACK 19

transmission from domestic sheep—by whatever mechanism

and involving whatever confounding factors—poses a

sufficient risk to bighorn sheep viability to merit separation

of the bighorns from the domestic animals. Confirming that

conclusion, numerous agencies with jurisdiction over bighorn

sheep have found the risk significant enough to compel

modification of their management plans. See section I.B.,

supra.

Because the lack of consultation did not prevent the

Forest Service or the public from considering information

about the uncertainties in transmission of disease from

domestic to bighorn sheep such as ARS would have offered

(and which Dr. Knowles later did offer), and because

information about the precise mechanisms of such

transmission was not a basis of the Forest Service’s decision,

no prejudice resulted from the lack of consultation.

WoolGrowers maintains that its member wool companies

were prejudiced—some of them went out of business due to

the Forest Service’s ultimate decision, they claim. But this is

not the type of prejudice with which NEPA is concerned. 

Rather, the question is whether the failure to consult

somehow materially altered the environmental review

process, not whether a constituent body was harmed by the

agency’s ultimate decision. See Cnty. of Del Norte v. United

States, 732 F.2d 1462, 1466–67 (9th Cir. 1984). Almost

invariably, some individuals or entities are negatively

affected by an agency decision. As long as “[t]he integrity of

the decision making process within the government and the

public’s opportunity to comment in accordance with all legal

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requirements were not compromised in any way,” id., there

is no prejudice of the sort with which NEPA is concerned.3

Accordingly, we conclude that any error arising from the

Forest Service’s failure to consult was harmless.

B. Supplementation

Wool Growers next challenges the Forest Service’s

failure to supplement the FSEIS. “Agencies . . . [s]hall

prepare supplements to either draft or final environmental

impact statements if . . . [t]here are significant new

circumstances or information relevant to environmental

concerns and bearing on the proposed action or its impacts.” 

40 C.F.R. §1502.9(c). But “an agency need not supplement

an EIS every time new information comes to light after the

EIS is finalized.” Marsh v. Or. Nat. Res. Council, 490 U.S.

360, 373 (1989). So requiring “would render agency

decisionmaking intractable, always awaiting updated

information only to find the new information outdated by the

time a decision is made.” Id. Thus, only “if the new

information is sufficient to show that the remaining action

will affect the quality of the human environment in a

significant manner or to a significant extent not already

considered, [must] a supplemental EIS . . . be prepared.” Id.

at 374 (alteration and citation omitted).

3 The Forest Service also argues that any prejudice was cured by the

thorough vetting in the district court of disease transmission questions, as

expressed in the parties’ expert declarations. This extra-record evidence

does not cure the prejudice—the question of harmlessness is as to the

effect of an error on the NEPA process. The expert declarations were

submitted well after the NEPA process was complete. They cannot,

therefore, cure any prejudice, although they are informative as to whether

prejudice occurred.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 21

Here, Wool Growers contends that publication of the

Lawrence study in 2010, after the FSEIS issued, triggered the

Forest Service’s duty to supplement. But: (1) the Forest

Service cited and discussed the study, in unpublished form,

numerous times in the FSEIS; (2) the study bolstered the

Forest Service’s decision by confirming that pneumonialinked bacteria were transmitted from domestic to bighorn

sheep, and that the transmitted bacteria likely caused the

pneumonia that killed the bighorns in the study;

4

and (3) the

study, while confirming bacterial transmission between the

species in a manner not yet definitively proven, reaffirmed

the scientific consensus regarding the risk domestic sheep

present to bighorn sheep, as discussed in the FSEIS and ROD.

The FSEIS stated, for example, that “the vast majority of

literature supports the potential for disease transmission

between the species, documents bighorn die-offs near

domestic sheep, and supports the management option of

keeping these species separate to prevent disease

transmission.” FSEIS 3-14. The Lawrence study was fully

in accord with the literature reported, and indeed was taken

into account by the FSEIS in making that statement. See id.

It was eminently reasonable for the Forest Service to

determine that the publication of the Lawrence study in

essentially the form relied upon in the FSEIS did not provide

significant information not already considered.

Wool Growers also argues that the Forest Service should

have supplemented the FSEIS in light of Dr. Knowles’

critiques of the Lawrence study. But Dr. Knowles’ critiques

 

4 Wool Growers has not argued that the published version of the study

differs materially from the unpublished form to which the FSEIS cited,

and the Forest Service maintains there is no material difference.

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22 IDAHO WOOL GROWERS ASS’N V. VILSACK

either: (1) conflict with the express findings of the study, of

which he was an author; or (2) state once more his views

regarding the lack of certainty in disease transmission

mechanisms. As to the former, it was reasonable for the

Forest Service to decide that certain of Dr. Knowles’

comments—which contradict the study’s conclusion that its

“results unequivocally demonstrate transmission of M.

haemolytica from domestic to bighorn sheep, resulting in

pneumonia and death of bighorn sheep”—did not represent

“significant” new information. The responses from other

authors of the Lawrence study disputed Dr. Knowles’

characterization of the results of the study, indicating that the

Forest Service reasonably concluded that Dr. Knowles’

critiques did not undermine the relevance of the study’s

conclusion. And as to the latter, the Forest Service could

reasonably have decided that Dr. Knowles’ comments

regarding the unproven and unknown mechanisms of disease

transmission were already well addressed in the FSEIS, as

discussed above, and therefore that his additional comments

to the same effect did not trigger its duty to supplement the

FSEIS. Supplementation is not required where the agency,

having taken a “hard look” at reevaluation, “determines that

the new impacts will not be . . . significantly different from

those already considered.” N. Idaho Cmty. Action Network v.

U.S. Dep’t of Transp., 545 F.3d 1147, 1154–55 (9th Cir.

2008) (per curiam).

We conclude that the Forest Service did not act arbitrarily

or capriciously or abuse its discretion by declining to

supplement the FSEIS.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 23

C. Models

Wool Growers’ final challenge is to the modeling the

Forest Service used to analyze bighorn sheep home ranges

and movement, and the potential impacts of various

management alternatives.

The framework for evaluating such challenges is wellestablished. “Agencies [must] insure the . . . scientific

integrity[] of the discussions and analyses in environmental

impact statements.” 40 C.F.R. § 1502.24. Moreover, “NEPA

requires that [EISs] contain high-quality information and

accurate scientific analysis.” Lands Council v. Powell, 395

F.3d 1019, 1031 (9th Cir. 2005) (citing 40 C.F.R.

§ 1500.1(b)). If relevant data is incomplete or unavailable,

the EIS “must disclose this fact.” Id. Thus, when an agency

uses models in its NEPA analysis, it must provide “up-front

disclosures of relevant shortcomings in the data or models.” 

Id. at 1032. When an agency undertakes technical scientific

analyses, as with the development of models to help analyze

a problem, the court’s deference to the agency’s judgment is

at its peak. Lands Council, 537 F.3d at 993.

1. Risk of contact model

The first model with which Wool Growers takes issue is

the risk of contact model. Wool Growers argues that model

failed adequately to take into account obstacles to bighorn

sheep mobility, including rivers and mountains.

The Forest Service used one aspect of the risk of contact

model—the core herd home range analysis—to map the home

ranges for the fifteen herds in the Payette, as well as one

“area of concern.” The home range boundaries were

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24 IDAHO WOOL GROWERS ASS’N V. VILSACK

developed using telemetry data from radio-collared bighorn

sheep. A second aspect of the model, the foray analysis, was

used to map the distances bighorn sheep travel outside their

home ranges. The Forest Service used the model, overall, to

predict whether a given foray by a bighorn from its core

home range would intersect a grazing allotment between May

and October, the months during which domestic sheep were

permitted to graze in the Payette. Contrary to Wool Growers’

argument, the risk of contact model does take into account

obstacles to mobility. The model incorporates telemetry data

of actual bighorn sheep movements within the Payette. That

data necessarily accounts for any topographical features that

impede bighorn mobility, as it indicates the distances bighorn

sheep actually move across the landscape.5 Also, bighorns’

chosen habitat is rugged, including steep, rocky terrain that

permits them to escape from predators. Thus, much of the

Payette’s mountainous terrain does not serve as a barrier to

bighorn sheep movement, although it might be a barrier to the

movement of other species. And the Forest Service has

pointed to evidence indicating that rivers are not obstacles to

bighorn sheep, as they have been known to swim across the

largest ones in the region. See W. Watersheds Project v.

BLM, No. 09-0507-E-BLW, 2009 WL 3335365, at *4 (D.

Idaho Oct. 14, 2009). Wool Growers’ argument that the risk

of contact model failed to account for barriers to movement

therefore fails.

Wool Growers next contends that the risk of contact

model should have been validated by comparing the model’s

5 The FSEIS also notes that, for various reasons, the telemetry data does

not include some of the longest forays. It therefore underestimates the

distances moved by bighorn sheep and thus the extent to which they are

able to traverse challenging terrain. See FSEIS 3-35–36.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 25

predicted values with actual values to assess the model’s

reliability. Neither the Forest Service nor Intervenors directly

respond to this argument, although both generally note that

the models: (1) were developed by leading experts in the

field; (2) were derived from peer-reviewed and published

models used to study bighorn sheep movements in the Sierra

Nevada mountains of California; and (3) rely on a large data

set reflecting actual bighorn sheep movements in the Payette.6

We reject Wool Growers’ argument. The Forest Service

is owed greater-than-average deference as it relates to its

choice of technical methodologies. Also, as the

methodologies used to construct the risk of contact model

were peer-reviewed and used successfully elsewhere, it was

not unreasonable for the Forest Service to rely on the model,

adjusted to fit local circumstances in the Payette. The model

was reliable as a predictor of actual movements because it

was predicated on data depicting actual bighorn sheep

movements. Given the model’s Payette data-based origin, the

Forest Service could reasonably assume that its predictions

were sufficiently reliable to satisfy NEPA.

Ultimately, the Forest Service used top-rate model

designers; relied on peer-reviewed methodologies applied by

other bighorn researchers addressing similar issues; and

incorporated on-the-ground data of bighorn sheep movements

within the Payette. Given the foregoing, and in light of the

6 Wool Growers also challenge the risk of contact model on the ground

that two of the Forest Service’s experts expressed conflicting views

regarding whether the model takes into account barriers to bighorn sheep

forays. Even assuming the experts’statements conflict—and it is not clear

they do—those statements, which were presented only at the district court,

did not in any way affect the analysis in the FSEIS, which we find

reasonable.

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deference owed to the agency when undertaking technical

analysis within its purview, the Forest Service’s reliance on

the risk of contact model was not arbitrary, capricious, or an

abuse of discretion. Cf. Lands Council, 537 F.3d at 990–94

(holding that the Forest Service did not act arbitrarily and

capriciously by failing to verify its model with on-the-ground

data).

2. Disease model

Wool Growers asserts two final points of error, related to

the Forest Service’s disease model. Wool Growers contends

the model did not consider the effects of time on disease

transmission, including both when and for how long bighorn

and domestic sheep will be in contact with one another in the

Payette, as well as the precise timing and period of contact

necessary for transmission to occur.

Determining both the amount of time bighorn and

domestic sheep spend cohabiting and the effects of timing on

disease transmission involve uncertainties acknowledged by

the Forest Service in the FSEIS. The degree to which both

kinds of uncertaintyaffect the usefulness of the disease model

can be resolved by the same three responses, as the Forest

Service explained in the FSEIS: 

(1) The disease model was not designed to predict actual

disease outbreak probabilities. Instead, the Forest Service

used the model to predict the likelihood that extirpation of

bighorn sheep subpopulations would result from various

alternative management plans, assuming probabilities of

disease transmission risk ranging from 5% to 100%. The

Forest Service did not use the disease model to predict a

particular level of actual risk.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 27

(2) Because the steps of disease transmission are

uncertain—including the duration of contact between bighorn

and domestic sheep and the precise timing and coincidence of

events necessary for transmission to occur—the Forest

Service ran the model at multiple different probability values. 

By using the model to test various proposed plans at different

risk levels, the Forest Service accounted for the uncertainty

of the variables involved.

(3) Most importantly, the Forest Service clearlyexplained

the assumptions on which it built the model and the

uncertainties inherent in it, thereby identifying the model’s

limitations. The FSEIS states, for example: “We do not

understand all of the mechanisms involved in potential

disease transmission between the species,” FSEIS 3-13;

“[There is] so much uncertainty surrounding [the probability

of contact resulting in disease transmission] and essentially

no research . . . that would allow its estimation,” id. at 3-43;

and “[t]he complexity of the [disease transmission] model

and the number of variables whose estimation was necessary

to run it . . . imply a high degree of uncertainty of its results,”

id. at 3-56. Those explanations and acknowledgments are all

that NEPA requires. Powell, 395 F.3d at 1031–32 (citing 40

C.F.R. § 1500.1(b)). Were that not the case, government

actions affecting the environment, positively or negatively,

could be hamstrung by the need for unattainable scientific

certainty. 

Wool Growers points to additional available information

regarding domestic sheep movement within allotments—

grazing permits, operating instructions, and post-season

actual-use reports—the Forest Service could have used to

evaluate more accurately the likelihood that bighorn sheep

would cohabit with domestic sheep. But as the FSEIS

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28 IDAHO WOOL GROWERS ASS’N V. VILSACK

explained, so much uncertainty surrounds contact

probabilities that the Forest Service chose not to estimate the

likelihood of actual contact. Specifically, the FSEIS observed

that, while this information was relevant, it could not be

incorporated into the modeling because domestic sheep: (1)

graze differently on the allotments each year; and (2) could be

anywhere in the Payette between May and October, and could

stray during that time or be left behind after the grazing

season. Given these uncertainties, the Forest Service did not

act unreasonably by using a range of probabilities to model

the risk of disease transmission.

Wool Growers’ contention that the Forest Service should

have modeled a disease transmission probability of 0% fares

no better. If the disease transmission probability used was

0%, the models would necessarily show a 0% risk of

extirpation due to disease transmission for any possible

management plan. Because of the obviousness of this

outcome, a 0% value would not inform the environmental

review process. Perhaps the Forest Service could have used

a 1% probability to flesh out more fully the effects of disease

transmission, given various management alternatives. But in

the face of competing reasonable methodologies, we do not

substitute our judgment for that of the agency. That the

Forest Service could have chosen a different methodology

does not render the extensive analysis it undertook arbitrary

or capricious.7

7 The peer-reviewed Clifford study of bighorn sheep in the Sierra

Nevada assumed that, given contact between domestic and bighorn sheep,

the likelihood of disease transmission ranged from 50% to 100%. Here,

the Forest Service chose much more conservative probabilities for use in

its disease model.

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IDAHO WOOL GROWERS ASS’N V. VILSACK 29

In sum, the disease model was used for a limited purpose,

and, for that purpose, was sufficiently grounded in

scientifically acceptable methodology to shed some light on

the choice of an appropriate management plan. As the ROD

explained: “Determining the probability that a bighorn sheep

will reach an occupied [domestic sheep grazing] allotment [in

the Payette] and that contact between the species will result

in disease transmission is problematic,” partly because “there

is . . . essentially no research that would allow . . . estimation”

of the likelihood of disease transmission. ROD 12. Given

the Forest Service’s open acknowledgment of the model’s

limitations, the uncertainties inherent in estimating contact

and disease transmission, and the actual use of the

model—which was not to estimate actual probabilities of

disease transmission—the Forest Service’s development and

use of the disease model was not arbitrary, capricious, an

abuse of discretion, or otherwise contrary to law.

III.

In light of the foregoing, we conclude that the Forest

Service committed no reversible error in preparing the FSEIS

and ROD. Accordingly, we AFFIRM.

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