United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued October 2, 2008 Decided February 13, 2009

No. 07-5026

JOYCE M. HILL,

APPELLANT

v.

ROWAN W. GOULD, ACTING DIRECTOR, UNITED STATES FISH

AND WILDLIFE SERVICE, ET AL.,

APPELLEES

Appeal from the United States District Court

for the District of Columbia

(No. 99cv01926)

John F. Karl Jr. argued the cause and filed the briefs for

appellant.

Ellen J. Durkee, Attorney, U.S. Department of Justice,

argued the cause for federal appellees. With her on the brief

was Kathryn E. Kovacs, Attorney. Larry M. Corcoran,

Attorney, entered an appearance.

Before: HENDERSON,RANDOLPH, and GARLAND, Circuit

Judges.
2

Opinion for the Court filed by Circuit Judge RANDOLPH.

RANDOLPH, Circuit Judge: After winning a lawsuit

against the Secretary of the Interior, Joyce M. Hill filed an

application to recover her attorney’s fees and expenses under the

Equal Access to Justice Act, 28 U.S.C. § 2412. The district

court denied the application on the basis that the Secretary’s

position at the merits stage was substantially justified. Hill

appealed. We affirm. 

I.

The mute swan, a bird indigenous to Eurasia, was

introduced into the United States for ornamental purposes in the

19th and 20th centuries. Joyce Hill took up the cause of the

mute swan in 1999. She sued nineteen federal, state and private

defendants, complaining of numerous wrongs the mute swan

species had allegedly suffered. Her principal claim was that the

Secretary of the Interior improperly denied the species the

protection of the Migratory Bird Treaty Act, 16 U.S.C.

§§ 703-712. The Treaty Act limits inter alia the pursuit, hunting

and killing of migratory birds covered by four treaties to which

the United States is a party. See Humane Society v. Glickman,

217 F.3d 882, 884–85 (D.C. Cir. 2000). The Secretary of the

Interior wields broad authority to implement the treaties. 16

U.S.C. § 712(2); see also id. § 704. Pursuant to that authority,

the Secretary published a list of protected migratory birds in

1973 and revised it in 1985. List of Migratory Birds, 50 C.F.R.

§ 10.13 (1999). The list did not include the mute swan. 

 The district court held that the Secretary’s List of

Migratory Birds rested on a permissible construction of the

Treaty Act and granted the Secretary’s motion for summary

judgment. Hill v. Babbitt, No. 99-CV-1926, 2000 WL

33912018 (D.D.C. Sept. 27, 2000). On appeal, this court
3

 The Hill panel recounted the regulatory history. See 275 1

F.3d at 101–02. The first regulations implementing the Treaty Act in

1916 appeared to define “migratory bird” to include all swans, but in

1965 the Secretary added the requirement that the birds be

“indigenous to the United States.” See id. at 101 (quoting 30 Fed.

Reg. 5,650 (Apr. 21, 1965)). Two years later, the Secretary again

amended the regulations, adding a new definition that did not include

the indigenous requirement, without striking the old definition. Id. at

102. These dual definitions remained in effect until the Secretary first

published the disputed list in 1973. Id. 

reversed. In Hill v. Norton, 275 F.3d 98 (D.C. Cir. 2001), the

court held that the Secretary’s exclusion of the mute swan from

the protected bird list was arbitrary and capricious under the

Administrative Procedure Act. 

Hill’s winning claim turned on the meaning of a key

statutory term — “migratory bird” — which the Treaty Act did

not define at the time of Hill’s suit. The Act stated only that its

1

protections extend to “any migratory bird . . . included in the

terms of” four bilateral treaties that the United States signed

with Great Britain (on behalf of Canada), Mexico, Japan and the

Soviet Union. 16 U.S.C. § 703(a). Each treaty defines the

protected class of birds differently. See Hill, 275 F.3d at 100–01

(cataloguing the relevant treaty language). By the time Hill

appealed to this court, all parties agreed that the Canada Treaty

should control because it is the broadest of the four treaties. Id.

at 103–04. The introductory Proclamation to the Canada Treaty

refers to birds that “traverse” the signatory nations in their

“annual migrations.” Convention for the Protection of

Migratory Birds, U.S.-Gr. Brit., Aug. 16, 1916, 39 Stat. 1702

(“Canada Treaty”). The Canada Treaty also specifically

identifies “Anatidae, or waterfowl, including brant, wild ducks,

geese and swans” as a protected bird family. Id. art. I, § 1(a).
4

The Hill panel thought the relevant statutory and treaty

language “strongly indicate[d]” that the mute swan is a protected

migratory bird. 275 F.3d at 99. But the panel declined to hold

that the plain meaning “positively foreclosed” the Secretary’s

interpretation. Id. at 105. The court’s hesitation stemmed from

the unusual regulatory scheme, id. at 99, the novelty of the

question, and the traditional “great weight” that courts give to

the Executive Branch’s treaty interpretations, id. at 104 (quoting

Kolovrat v. Oregon, 366 U.S. 187, 194 (1961)).

The court considered whether, despite the ostensibly

plain text, the Secretary’s interpretation might be permissible.

Id. at 105. The Secretary offered three main reasons for

excluding the species: the mute swan is not native to the United

States; the mute swan is harmful to other protected bird species

and their environments; and extending protection to the mute

swan might conflict with other statutory obligations. See id. As

to the first two points, the court had “no idea whether these

arguments are pertinent, and, if so, whether they are compelling”

because the agency record was “barren” on those issues. Id. at

105. The court therefore held that the Secretary failed to justify

her interpretation and vacated the list insofar as it excluded the

mute swan. Id. at 107. 

II.

With a merits victory secure, Hill petitioned the district

court for an award of attorney’s fees pursuant to the Equal

Access to Justice Act. The Act authorizes an award of fees to a

party prevailing against the government unless the government

establishes that its position was “substantially justified or . . .

special circumstances make an award unjust.” 28 U.S.C.

§ 2412(d)(1)(A). A position is substantially justified if the

underlying agency action and the legal arguments in defense of

the action had “a reasonable basis both in law and fact.” Pierce
5

v. Underwood, 487 U.S. 552, 565 (1988) (citation omitted); see

also Halverson v. Slater, 206 F.3d 1205, 1208 (D.C. Cir. 2000).

That standard demands more than mere non-frivolousness, but

less than a showing that the government’s “decision to litigate

was based on a substantial probability of prevailing.” Taucher

v. Brown-Hruska, 396 F.3d 1168, 1173 (D.C. Cir. 2005)

(quoting Spencer v. NLRB, 712 F.2d 539, 557 (D.C. Cir. 1983)).

The district court concluded that the Secretary’s position was

substantially justified and denied Hill’s fee application on that

basis. We review the district court’s decision for abuse of

discretion. Id. at 1172. 

The Secretary’s chief argument before the merits panel

was that the Treaty Act did not apply to species of migratory

birds that were not native to North America. The Secretary

mustered ample evidence to support the factual assertion that the

mute swan is an exotic species. According to the Secretary’s

expert testimony and documentary evidence, all feral North

American mute swans are descended from escaped and released

members of ornamental groups introduced into the United

States.

In support of her assertion that the Treaty Act does not

apply to exotic species, the Secretary argued that the taxonomic

listing of bird families in Article I of the Canada Treaty reveals

a latent ambiguity in the otherwise unqualified term “migratory

birds.” The treaty lists protected bird families, and each family

name is followed by the common names of species and species

groups in each family. See Canada Treaty, art. I, § 1(a);see also

Protocol Amending the 1916 Convention for the Protection of

Migratory Birds in Canada and the United States (“Canada

Protocol”) art. I, § 1, U.S.-Can., Dec. 14, 1995, Sen. Treaty Doc.

104-28. According to the Secretary, each enumerated species

and at least some members of each enumerated group were

native to the signatory nations. By contrast, many nonnative
6

 In response to this court’s decision in Hill, the Migratory 2

Bird Treaty Reform Act amended the Migratory Bird Treaty Act to

limit its scope “only to migratory bird species that are native to the

United States or its territories.” Pub. L. No. 108-447, Div. E., Title I,

§ 143(b), 118 Stat. 2809, 3071 (codified at 16 U.S.C. § 703(b)(1)); see

also Fund for Animals v. Norton, 472 F.3d 872, 877 (D.C. Cir. 2006)

(noting the amendment was “a correction of what Congress believed

to be an erroneous judicial interpretation of a treaty”). The Secretary

argues that the Reform Act and its accompanying legislative history

show conclusively that the Secretary’s native-only interpretation was

reasonable. It is true that, in other contexts, some courts sometimes

treat an amendment that clarifies disputed statutory language as an

expression of the original act’s meaning. See, e.g., Wesson v. United

States, 48 F.3d 894, 900–01 (5th Cir. 1995); see also 1A N. Singer,

Sutherland Statutes and Statutory Construction § 22:31 (6th ed. 2008).

On the other hand, there is reason to doubt the interpretative value of

an amendment which, like the Reform Act, long postdates the

amended statute. Rainwater v. United States, 356 U.S. 590, 593

(1958); cf. Sullivan v. Finkelstein, 496 U.S. 617, 628 n.8 (1990). But

we need not decide the relevance of the Reform Act because we think

the Secretary’s position was reasonable even without it. 

species within each family were not listed. From that pattern,

the Secretary argued, the Secretary reasonably understood the

Canada Treaty to distinguish between native species and exotic

species introduced to North America by man. The Secretary

therefore believed it proper to limit the Treaty Act’s protections

to swan species native to North America.

2

The Secretary further argued that reading the treaties to

cover the mute swan would be a self-destructive interpretation.

The mute swan is a beautiful bird but it can be nasty. The

Secretary produced evidence that the species is a menace to

other birds protected by federal law. A territorial aggressor and

prolific procreator, the mute swan depletes native birds’ food

sources and occupies their nesting grounds. The Acting Director
7

 For example, the Secretary presented evidence that the entire

3

mute swan population of the Chesapeake Bay — where Hill alleged

aesthetic injury — descends from 5 ornamental swans that escaped

from waterfront estates in 1962.

of the U.S. Fish and Wildlife Service concluded that “mute

swans pose a serious threat to the ecological integrity of many

areas, including the National Wildlife Refuge System and other

Federal Lands committed to the maintenance of natural wildlife

diversity.”

The Secretary’s concern about the impact of destructive

exotic species like the mute swan had some basis in three of the

migratory bird treaties. Provisions in the treaty with Japan, the

treaty with the former Soviet Union, and the Canada Protocol

required the signatory countries to control the importation of

live animals that may be harmful to migratory birds or their

environments. See Convention for the Protection of Migratory

Birds and Birds in Danger of Extinction, and Their

Environment, art. VI, U.S.-Japan, Mar. 4, 1972, 25 U.S.T. 3331;

Convention Concerning the Conservation of Migratory Birds

and their Environment, art. IV § 2(b), U.S.-U.S.S.R., Nov. 19,

1976, 29 U.S.T. 4649; Canada Protocol, art. IV. The Secretary

also pointed out that some mute swans in North America were

introduced only after the signing of the first migratory bird

treaty in 1916.3

Of course the Secretary’s position did not prevail. But

the question is not whether the Secretary had the better

arguments. It is enough that the Secretary’s interpretation and

legal arguments had a reasonable basis in fact and in the text and

purpose of the controlling statute and treaties. There was

nothing unusual or unsound about the Secretary’s basic premise

that an enactment’s context and underlying policies can cast

doubt on “‘the most natural reading’ of a statutory phrase.”
8

Tataranowicz v. Sullivan, 959 F.2d 268, 276 (D.C. Cir. 1992)

(quoting McCarthy v. Bronson, 500 U.S. 136, 139 (1991)). Nor

did the Secretary’s justification suffer from the defects common

to positions that are not substantially justified. It was not “flatly

at odds with the controlling case law,” Am. Wrecking Corp. v.

Sec’y of Labor, 364 F.3d 321, 326–27 (D.C. Cir. 2004) (internal

quotation marks omitted), and the Secretary certainly did not

press her position in “the face of an unbroken line of authority,”

Precision Concrete v. NLRB, 362 F.3d 847, 851–52 (D.C. Cir.

2004), or against a “string of losses,” Contractor’s Sand &

Gravel, Inc. v. Fed. Mine Safety & Health Review Comm’n, 199

F.3d 1335, 1341 (D.C. Cir. 2000) (internal quotation marks

omitted). We are satisfied that the district court acted within its

discretion in concluding that the Secretary’s position was, on the

whole, “justified to a degree that could satisfy a reasonable

person.” Underwood, 487 U.S. at 565. 

That assessment is consistent with the merits panel’s

reasoning. See Taucher, 396 F.3d at 1174. The panel did not

resolve the Secretary’s arguments concerning the

native–nonnative distinction or the bird’s ecological impact

either way. Instead the panel stated that these arguments

amounted to “post hoc rationalizations” which could not save

the regulation. Hill, 275 F.3d at 105 (quoting Burlington Truck

Lines, Inc. v. United States, 371 U.S. 156, 168 (1962)). The

Secretary lost because the agency record was “utterly silent on

any basis, let alone any reasonable basis, to support exclusion of

the mute swan from the List of Migratory Birds.” Id. 

At the fee stage, however, an inadequate agency record

is not necessarily fatal. See F.J. Vollmer Co., Inc. v. Magaw,

102 F.3d 591, 595 (D.C. Cir. 1996). We explained in FEC v.

Rose, 806 F.2d 1081 (D.C. Cir. 1986), that the “adequacy of an

agency’s explanation” is in some cases “logically unrelated to

whether the underlying agency action is justified under the
9

The fee stage analysis focuses on the reasonableness of the 4

government’s position at the “time the government took this position.”

Trahan v. Brady, 907 F.2d 1215, 1219 (D.C. Cir. 1990). The

government first took its litigation position before Mead was decided.

organic statute,” id. at 1088. In this case, the Secretary took a

reasoned position on a novel issue, and the sparse agency record

did not “obviously defy the requirements of the [Administrative

Procedure Act].” Id. at 1089. The void in the record did not

result from the Secretary’s failure to respond to “relevant and

significant” comments. Grand Canyon Air Tour Coal. v. FAA,

154 F.3d 455, 468 (D.C. Cir. 1998). To the contrary, Hill

identified no comment by any party concerning the exclusion of

nonnative birds in response to the agency’s notices of proposed

rulemaking in 1973 and in 1984. 38 Fed. Reg. 10,208 (Apr. 25,

1973); 49 Fed. Reg. 23,197 (June 5, 1984).

Nor can we fault the Secretary for thinking the court

might accept counsel’s elaboration of the Secretary’s

interpretation. At least until the Supreme Court’s decision in

United States v. Mead Corp., 533 U.S. 218 (2001), this court in

some circumstances deferred to agency interpretations of

statutes and regulations articulated for the first time in legal

briefs. See, e.g., Ass’n of Bituminous Contractors, Inc. v. Apfel,

4

156 F.3d 1246, 1252 (D.C. Cir. 1998) (deferring to an agency’s

litigation position interpreting a statute where it appeared simply

to articulate an explanation of longstanding agency practice);

Nat’l Wildlife Fed’n v. Browner, 127 F.3d 1126, 1129 (D.C. Cir.

1997). The Secretary took a reasonable approach to that

relatively unsettled area of administrative law. See Lundin v.

Mecham, 980 F.2d 1450, 1460 (D.C. Cir. 1992).

In sum, the thinness of the agency record at the merits

stage does not alter our conclusion that the Secretary’s
10

We also deny Hill’s request to increase her award of costs 5

under Federal Rule of Civil Procedure 54(d) because she has not

shown that the district court abused its discretion in calculating the

costs.

interpretation and arguments had a reasonable basis in fact and

law. The district court did not abuse its discretion in so finding.5

Affirmed.