FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

In re: B.   DEL   C. S. B., (minor),       
                                                 No. 08-55067
IVAN NEMECIO SALMERON MENDOZA,
              Petitioner-Appellee,                D.C. No.
                                                CV-07-00290-CJC
               v.
                                                   OPINION
GEREMIAS BRITO MIRANDA,
           Respondent-Appellant.
                                           
         Appeal from the United States District Court
            for the Central District of California
         Cormac J. Carney, District Judge, Presiding

                      Argued August 7, 2008
                   Submitted September 22, 2008
                       Pasadena, California

                        Filed March 18, 2009

       Before: Stephen Reinhardt, Roger J. Miner,* and
              Marsha S. Berzon, Circuit Judges.

                    Opinion by Judge Reinhardt




   *The Honorable Roger J. Miner, Senior United States Circuit Judge for
the Second Circuit, sitting by designation.

                                 3449
3452                MENDOZA v. MIRANDA




                         COUNSEL

Mark T. Cramer and Elisa L. Miller, Kirkland & Ellis LLP,
for the respondent-appellant.

Lori R.E. Ploeger, Maureen P. Alger, and Christopher B. Dur-
bin, Cooley Godward Kronish LLP, for the petitioner-
appellee.


                         OPINION

REINHARDT, Circuit Judge:

   It is never an easy nor a joyous task to resolve a dispute
between parents that may determine the custody of their child;
nor is the outcome ever fully satisfactory. Frequently, both
sides offer appealing, indeed compelling, arguments. Yet,
both cannot prevail. Hague Convention cases are surely no
exception to that rule. Nevertheless, we must decide here
                        MENDOZA v. MIRANDA                        3453
whether a child of Mexican origin, whose mother wrongfully
retained her in the United States, should be allowed to stay in
her current home while custody proceedings are conducted in
the United States, or whether she should be returned to Mex-
ico while the proceedings are conducted there.

   To decide this issue, we must consider a question of first
impression in our circuit: whether a court may find that a
child is not “settled” for the purposes of Article 12 of the
Hague Convention for the reason that she does not have law-
ful immigration status. We must also decide whether, in this
case, the mother “concealed” the child’s whereabouts, so that
the father is entitled to equitable tolling of the one-year filing
period set forth in Article 12. On both questions, we conclude
that the answer is no.

      I.   Overview of the Hague Convention on the Civil
            Aspects of International Child Abduction
                     (“Hague Convention”)

   The Hague Convention, to which both the United States
and Mexico are parties,1 was enacted “to protect children
internationally from the harmful effects of their wrongful
removal or retention and to establish procedures to ensure
their prompt return to the State of their habitual residence
. . . .” Hague Convention, preamble. “[T]he Convention’s
drafters were concerned primarily with securing international
cooperation regarding the return of children wrongfully taken
by a parent from one country to another, often in the hope of
obtaining a more favorable custody decision in the second
country.” Gonzales v. Gutierrez, 

, 944 (9th Cir.
2002); see also Hague Convention art. 3 (explaining when the
  1
   The United States Congress implemented the Convention’s provisions
in 1988 with the passage of the International Child Abductions Remedies
Act (“ICARA”), 42 U.S.C. § 11601 et seq. Mexico became a party to the
Convention in 1991. See Duarte v. Bardales, 

, 568 & n.7 (9th
Cir. 2008).
3454                     MENDOZA v. MIRANDA
removal or retention of a child is “wrongful”).The Convention
seeks generally to accomplish its aim by preventing an
abducting parent from benefitting from his actions by requir-
ing that a wrongfully removed child be returned to the country
of its habitual residence for custody proceedings. See Hague
Convention art. 12. The Convention explicitly does not pur-
port to resolve the merits of any underlying custody disputes.
See Hague Convention art. 19; see also 

. Rather, “[t]he Convention’s focus is . . . whether a child
should be returned to a country for custody proceedings and
not what the outcome of those proceedings should be.”
Holder v. Holder, 

, 1013 (9th Cir. 2004).

   Despite the Convention’s “desire to guarantee the re-
establishment of the status quo disturbed by the actions of the
abductor,” its drafters recognized the need for several impor-
tant exceptions to the general rule of return. Elisa Perez-Vera,
Explanatory Report ¶ 18, 3 Hague Conference on Private
International Law, Acts and Documents of the Fourteenth
Session, Child Abduction 426 (1982) [hereinafter “Perez-
Vera Report”].2 One such exception is the affirmative defense
provided in Article 12: If the abducting parent can show that
the petition for return was filed more than a year after the
wrongful removal or retention occurred, and “that the child is
now settled in its new environment,” the abducting parent can
overcome the presumption in favor of return. Hague Conven-
tion art. 123; see also 42 U.S.C. § 11603(e)(2)(B); Duarte,
   2
     The “Perez-Vera Report” is “recognized by the Conference as the offi-
cial history and commentary on the Convention and is a source of back-
ground on the meaning of [its] provisions.” Shalit v. Coppe, 

, 1127-28 (9th Cir. 1999) (internal citation omitted).
   3
     The other exceptions to the Convention’s return mandate are: (1) con-
sent to or acquiescence in the removal or retention by the non-abducting
parent, (2) that return poses a grave risk of physical or psychological
harm, or would place the child in an intolerable situation, (3) the objection
of a child that “has attained an age and degree of maturity at which it is
appropriate to take account of its views,” and (4) the return would not
comport with “the protection of human rights and fundamental freedoms.”
Hague Convention arts. 13, 20.
                         MENDOZA v. MIRANDA                           

. The rationale behind Article 12’s “now set-
tled” defense is that when “a child has become settled and
adjusted in [his new environment, a] forced return might only
serve to cause him or her further distress and accentuate the
harm caused by the wrongful relocation.”). Beaumont &
McEleavy, The Hague Convention on International Child
Abduction 203 (1999); see also Perez-Vera Report ¶ 107
(explaining that “it is clear that after a child has become set-
tled in its new environment, its return should take place only
after an examination of the merits of the custody rights exer-
cised over it . . . .”).

   The Convention does not provide a definition of the term
“settled.” However, the U.S. State Department has declared
that “nothing less than substantial evidence of the child’s sig-
nificant connections to the new country is intended to suffice
to meet the respondent’s burden of proof.” Public Notice 957,
Text & Legal Analysis of Hague International Child Abduc-
tion Convention, 51 Fed. Reg. 10494, 10509 (U.S. State Dep’t
Mar. 26, 1986).

                          II.    Background

   Ivan Nemecio Salmeron Mendoza (“Salmeron”) and
Geremias Brito Miranda (“Brito”) are the unmarried parents
of eleven-year-old Brianna. Both parents are Mexican citi-
zens; neither has legal status in the United States.4 Brito was
born in Mexico and was brought by her mother
(“Grandmother Brito”) to the United States in 1981, when she
was one or two years old. She has lived the majority of her
life in Southern California, where she has a large extended fam-
ily.5 Salmeron lived in the United States between 1988 and
1996.
  4
     Although Brito does not currently have legal status, her mother, a U.S.
citizen, testified that she submitted “papers” to immigration authorities in
an effort to help Brito gain such status. If her mother were successful,
Brito would be able to file for lawful permanent resident status for Bri-
anna.
   5
     Brito’s mother lives in Garden Grove, her aunt lives in Los Angeles,
and several of her brothers and sisters live in Westminster. She also has
3456                    MENDOZA v. MIRANDA
   Salmeron and Brito met and began dating in Santa Ana,
California in 1994. Salmeron was twenty-four years old at the
time, and Brito was fourteen. In 1995, the couple moved to
Oregon. While living in Oregon, Salmeron was arrested on
three separate occasions, including once for driving under the
influence, once following a domestic dispute with Brito while
she was pregnant with Brianna, and once, in 1996, for drug
trafficking. The last arrest led to his deportation to Mexico. In
the fall of 1996, Salmeron re-entered the United States with-
out documentation and reunited with Brito. In December
1996, the couple decided to return to Mexico and live with
Salmeron’s mother (“Grandmother Salmeron”) in Acapulco
rather than appear at court proceedings related to Salmeron’s
arrests. Brito was about six months pregnant with Brianna at
the time.

   On April 17, 1997, Brianna was born in Acapulco, Mexico.
The new parents struggled for the next four years to provide
for their daughter. They lived at Grandmother Salmeron’s
home in Acapulco. Salmeron worked long hours; Brito and
Grandmother Salmeron stayed home and cared for Brianna.

   Both Brito and Salmeron describe their relationship during
this time as abusive. Brito claims that Salmeron often came
home drunk and beat her, and that Brianna saw and heard this
happening. She also claims that he was unfaithful to her, and
that she had to bail him out of jail on several occasions
because of weapons and drug-related incidents.6 Salmeron
also described mistreatment. He submitted a copy of a local
court document recounting Brito’s physical and verbal abuse,
including an incident in which Brito allegedly attacked him
with a knife.

a sister in Las Vegas, an older brother in San Francisco, an uncle in Ore-
gon and other family in Washington.
   6
     Brito submitted no evidence to support her claims of abuse. In order
to counter her claims, Salmeron provided an uncertified letter from the
Mexican police stating that he has no criminal record in the country.
                        MENDOZA v. MIRANDA                          3457
   In February 2001, Brito decided to move back to the United
States. She and Brianna traveled into California illegally by
way of the Tijuana border crossing and moved into Grand-
mother Brito’s home in Garden Grove, California. At the
time, Salmeron was under the impression that the couple
would reunite either in the United States or Mexico. Brito, by
contrast, testified that she intended her relocation back to the
United States to be permanent, and that she considered her
relationship with Salmeron to be over upon her departure
from Mexico. Brito did not, however, discuss these senti-
ments with Salmeron. Both parties testified that they were
regularly in contact by telephone and mail after Brito’s move,
and that Brianna and Salmeron spoke often.

   In June 2001, Brito and Salmeron decided that Brianna
should return to her father in Mexico. Brito could not yet reg-
ister Brianna for school because she was only four years old,
a year below the minimum age requirement. In addition, Brito
had just lost her job and could not afford to care for Brianna.
Thus, on June 15, Grandmother Salmeron accompanied Bri-
anna back to Acapulco, where Salmeron enrolled her in a pri-
vate summer school program and arranged for her to start
school that fall. Again, the three were regularly in contact by
telephone and mail while Brianna completed a year of pre-
school.

  In August 2001, while Brianna was living with her father,
Brito began a romantic relationship with Aiden Aguilar, who
subsequently became her fiancé. In December of that year, the
two moved into their current Huntington Beach apartment
together. Salmeron was made aware of Brito’s new address
within two months of her move, as evidenced by the DHL
packing slip that was affixed to a package he sent to her on
February 26, 2002.7
  7
   Although aware of the new address, Salmeron was not aware of Brito’s
new relationship. Rather, he thought that she was living with a female co-
worker.
3458                     MENDOZA v. MIRANDA
   As Brianna’s school year came to an end, Brito and Sal-
meron agreed that Brianna would travel back to California to
stay with her mother. In June 2002, Brianna returned to the
United States and moved into Brito’s new apartment. Sal-
meron’s understanding was that this was a temporary arrange-
ment, as he had already registered Brianna for the 2002-2003
school year in Mexico. However, Brito claims that Brianna
was being sent to her permanently to await Salmeron’s arrival
in the United States, and that she never had any intention of
returning the child to Acapulco.

   That August, Brianna mentioned in a telephone conversa-
tion with her father that her mother was in a relationship with
another man, and that her mother was pregnant. Salmeron tes-
tified that he then requested that Brianna be returned to him
so that she could start school in September. He testified that
he asked Brito to return their daughter to Mexico approxi-
mately five different times, but that Brito refused to send her
back. Eventually, Salmeron agreed to allow Brianna to stay in
the United States on condition that he would be able to speak
with her on the telephone and see her during school holidays.

   In the fall of 2002, Brianna began kindergarten in Hunting-
ton Beach. Salmeron was initially able to maintain contact
with her. That communication ended, however, in late 2002
or early 2003. The parties differ in their explanations of the
reason this occurred,8 but neither party disputes that commu-
   8
     According to Salmeron, Brito cut off their communication because she
was frustrated that Brianna would cry that she missed her father. Brito, on
the other hand, claims that she was forced to end communications with
Salmeron because he made a number of drunken calls in the middle of the
night that upset and “traumatized” Brianna. The district court found that
the drunken calls most likely occurred in 2001, when Brito was still living
with her mother (who, according to Brito, was also upset by the calls). The
court therefore found that the calls were “unlikely to have been the actual
grounds for Ms. Brito’s decision to change her telephone number in
2002.” In re B. del C.S.B., 

, 1187 n.9 (C. D. Cal.
2007).
                     MENDOZA v. MIRANDA                   3459
nication was eventually completely cut off between father and
daughter.

   Salmeron testified that when he called the numbers he
believed to be Brito’s after January 2003, he received mes-
sages that stated that she could no longer be reached at her
home number and that her cell number was out of service. He
did not attempt to contact Brito at her work telephone num-
ber, which Brito contends he possessed and which remained
the same throughout. He did, however, contact Grandmother
Brito to try and find a working phone number for Brito and
Brianna. Grandmother Brito allegedly informed him that Brito
had moved from the Huntington Beach apartment, and that
she was forbidden to disclose Brito’s new telephone number.
Brito admits that she changed her telephone number and told
her mother not to provide Salmeron with her new number.
However, she denies telling her mother to inform Salmeron
that she had moved. Even though Grandmother Salmeron was
then living in the area and maintained contact with Grand-
mother Brito, Salmeron never requested that his mother drive
by the Huntington Beach apartment to confirm that Brito had
actually moved.

   During the more than five years between Salmeron’s last
contact with Brianna and the present, each party’s personal
life has progressed in new directions. Brito gave birth to her
son, Brianna’s half-brother, Brian Aguilar, on March 8, 2003,
and has since become engaged to the child’s father. She also
testified that she has a business in Huntington Beach doing
restaurant maintenance, and that her fiancé works as a chef at
a local restaurant. Salmeron makes his living driving a taxi in
Acapulco, where he and his girlfriend Jasmine have been liv-
ing together since he left his mother’s home in 2003. Sal-
meron now has a son as well, Brianna’s half-brother, to whom
Jasmine gave birth in October 2003. Grandmother Salmeron,
a U.S. citizen, spends the majority of her time with her other
children, in either Riverside, California or Denver, Colorado.
3460                     MENDOZA v. MIRANDA
The Acapulco home in which Brianna used to live is currently
vacant.

   Most important, Brianna’s life has developed in significant
ways. She has completed the first through fourth grades, and
was scheduled to begin the fifth grade at the same school last
fall. Brianna’s report cards reflect consistently good grades
and attendance and demonstrate that she is progressing well
both academically and socially. She is bilingual: she can
speak, read, and write in both English and Spanish. Her teach-
ers describe Brianna as a child who is “eager to learn.” While
her favorite subject in school is math, she also “excel[s]” in
science and social studies, and her registration records indi-
cate no significant periods of absence. After she finishes her
homework and on the weekends, Brianna likes swimming,
going to the park to play volleyball, baseball, and basketball
with her younger half-brother and his father, Brito’s fiancé,
and playing soccer with the team of which she is the captain.

  Despite all of the changes in the family members’ lives,
certain significant factors have remained the same. Brito and
Brianna have continued to reside in the same Huntington
Beach apartment that Brito rented with Aguilar in December
2001. Brianna has been enrolled under her own given name
and surname in the same public school for the entire time she
has been in the United States.

   Since their last telephone conversation in January 2003,
Salmeron has consistently attempted to renew his relationship
with Brianna. Although he has been unable to speak with his
daughter, Salmeron sent gifts and money by way of his
mother, who would pass them on to Grandmother Brito for
delivery. Salmeron also engaged in legal efforts to re-
establish contact, beginning in July 2003, when Grandmother
Salmeron visited the Mexican Consulate in Santa Ana, Cali-
fornia on his behalf.9 She was told that Salmeron would have
  9
    Salmeron testified that he waited approximately six months to begin
pursuing potential legal remedies because until that point he still “held out
hope” that Brito’s relationship with Aguilar would end and that she would
decide to send Brianna back to Mexico on her own.
                     MENDOZA v. MIRANDA                     3461
to contact officials in Acapulco for help. A month later, Sal-
meron visited the Office of Family Integration Services in
Acapulco, which then referred him to the Minors Protection
Department in Chilpancingo, located about two hours from
his home. Salmeron claims that he visited this office on four
separate occasions before he was referred to the Department
of State for Protection of Minors in Mexico City, a twelve-
hour round-trip car ride from Acapulco. Salmeron testified
that he traveled between Acapulco and Mexico City approxi-
mately eighteen times, and slept outside the State Department
building at least once in an effort to determine the where-
abouts of his daughter.

   During one of his trips to Mexico City, Salmeron secured
a meeting with the head of the appropriate section in the State
Department, who subsequently gave him an application to
begin the Hague petition process, which he completed without
the assistance of counsel. He testified that these officials
advised him to include Grandmother Brito’s Garden Grove
address on his application, as he thought that Brito had left the
Huntington Beach apartment and he did not have any other
address for her. In October 2003, Salmeron submitted the
completed application in Spanish, but was informed that he
was required to submit it in English as well. He therefore
mailed the materials to Grandmother Salmeron in the United
States and waited for almost seven months for the return of
the translated application and birth certificate.

   On March 26, 2004, more than a year after his last contact
with Brianna, Salmeron submitted his Hague application to
the Mexican Central Authority for processing. The Mexican
Central Authority advised him not to take any further action,
and to let the “long” Convention process run its course. On
April 2, 2004, the Mexican Central Authority transmitted the
application to the United States Central Authority. On April
26, 2004, the National Center for Missing and Exploited Chil-
dren (“NCMEC”) received Salmeron’s application from the
United States Central Authority, and forwarded a copy to the
3462                 MENDOZA v. MIRANDA
Office of the Attorney General of California. More than two
years later, on July 27, 2006, NCMEC located an address for
Brito and Brianna — the same address that Salmeron last had
for them — and sometime that following February, Brianna’s
presence in the Huntington Beach apartment was confirmed
by the Orange County District Attorney’s office.

   On March 9, 2007, more than four years after Salmeron’s
last telephone contact with Brianna and approximately one
month after he was advised by the authorities of her location
in the United States, Salmeron filed his Hague petition in the
United States District Court for the Central District of Califor-
nia. Brito opposed the petition on three grounds: (1) Brianna
could not have been wrongfully retained because the United
States was her habitual residence, (2) Salmeron forfeited his
custody rights by acquiescing to Brito’s desire to keep Bri-
anna in California, and (3) Salmeron’s petition was filed more
than one year after the alleged wrongful retention and Brianna
had since become settled in her new environment. An eviden-
tiary hearing was held on November 6 and 7, 2007. Salmeron,
Brito, Brianna, Grandmother Salmeron, and Grandmother
Brito all testified.

   On December 3, 2007, the district court granted Salmeron’s
petition. Specifically, the court found that Brito’s retention of
Brianna had become “wrongful” retention under the terms of
the Convention “sometime between Ms. Brito’s disclosure of
her new romantic relationship in August 2002 and Mr. Sal-
meron’s last conversation with Brianna in January 2003[,]”
that Brianna’s country of habitual residence prior to the
wrongful retention was Mexico, and that Salmeron did not
acquiesce in Brianna’s retention. In re B. del C.S.B., 525 F.
Supp. 2d at 1190-93. Further, the court held that Brito did not
satisfy her burden of proving an Article 12 defense because
Brianna’s unlawful immigration status precluded her from
being settled in the United States. 

The district
court ordered Brianna returned to Mexico for custody pro-
ceedings within thirty days.
                          MENDOZA v. MIRANDA                             3463
   Because the district court found that Brianna was not set-
tled in the United States, it did not reach the parties’ argu-
ments with respect to the timeliness of Salmeron’s petition
and the availability of equitable tolling, which would have
been relevant to defeating Brito’s Article 12 defense.10 How-
ever, the district court did note that it found credible Sal-
meron’s testimony with respect to Brito’s concealment of
Brianna and his efforts to locate her. 

n.22. Under
these facts, the court added that even if Brito had shown that
Brianna was well settled in the United States, it would be “en-
tirely reasonable” to toll the one year filing period until early
2007, when Brianna was located, and so to grant Salmeron’s
petition and order Brianna returned to Mexico for custody
proceedings. Id.11
  10
      As the district court noted, a petition “under the Hague Convention is
not subject to a traditional statute of limitations period.” 

Under
Article 12, if “a period of less than one year has elapsed” between the date
of the wrongful retention and the initiation of judicial proceedings, the dis-
trict court presumes that the child should be returned to its country of
habitual residence. Hague Convention art. 12. If a year or more has
passed, however, the parent who wrongfully retained the child may raise
an Article 12 defense by “demonstrat[ing] that the child is now settled in
its new environment” and so should not be removed. Id.; see also 42
U.S.C. § 11603(e)(2)(B); 

(“[T]he ‘well settled’
affirmative defense is only available if the petition for return was filed
more than a year from wrongful removal.”). So, in this case, the length of
time that passed between Brito’s wrongful retention and the filing of Sal-
meron’s petition with the district court is relevant to determining whether
Brito may raise an Article 12 defense against the presumption of return.
   11
      In reaching his decision, the district judge refused to rely on Brianna’s
preference to remain with her mother in the United States, as he was
empowered to do under Article 13 of the Hague Convention. 

99. The court noted that the child, who was ten at the time, appeared to
have been influenced by her mother’s description of events, because she
used words such as “harassed” and “lovable.” 

basis, the court
found that Brianna had not yet reached an age and degree of maturity such
that her preference should be taken into account. 

need not
consider Brianna’s preference in order to reach the conclusion we do, it
is not necessary for us to review the district court’s finding. Our failure
to do so does not, however, indicate agreement with the view that a child
of Brianna’s age who uses the words in question is necessarily influenced
by a parent.
3464                       MENDOZA v. MIRANDA
   Brito filed her timely Notice of Appeal on December 28,
2007, challenging only the district court’s denial of her Arti-
cle 12 defense. She contends that the district judge erred in
finding that Brianna was not settled in the United States solely
because she does not have legal status and that Salmeron is
not entitled to equitable tolling with respect to the filing of his
petition.

                    III.     Standard of Review

   We must decide as a matter of first impression the proper
standard of review to be applied to (1) a district court’s con-
clusion that a child is not “now settled” within the meaning
of Article 12 and (2) a district court’s determination that equi-
table tolling may be applied to the one-year filing period pro-
vided in Article 12. We conclude that we must review the
district court’s factual determinations for clear error, and its
application of the treaty to those facts de novo.

   In an analogous context, we have consistently held that a
determination of “habitual residence” under Article 3 of the
Hague Convention is “a mixed question of law and fact, under
which we review ‘essentially factual’ questions for clear error
and the ultimate issue of habitual residence de novo.” 

(quoting Mozes v. Mozes, 

,
1073 (9th Cir. 2001)); see also Papakosmas v. Papakosmas,

, 623 (9th Cir. 2007).12 We arrived at this stan-
dard of review by recognizing that “[d]espite the factual focus
of our inquiry, ultimately our conclusion rests on a legal
determination: After scrutinizing the circumstances of a par-
ticular case, we must determine whether the discrete facts add
  12
     Article 3 of the Hague Convention provides that a removal is wrong-
ful only where a child is removed in violation of the “law of the State in
which the child was habitually resident immediately before the removal
or retention.” Hague Convention art. 3 (emphasis added). The term “habit-
ual residence,” like the term “settled,” was left undefined by the Conven-
tion’s drafters. 

.
                          MENDOZA v. MIRANDA                            3465
up to a showing of habitual residence.” 

. Similarly, a conclusion as to whether a child is “settled”
in her new environment, though fact-specific, ultimately rests
on a legal determination of “whether the discrete facts add up
to a showing” that she is “settled” within the meaning of Arti-
cle 12. See id.; see also Blondin v. Dubois, 

, 158
(2d Cir. 2001) (reviewing de novo Article 13(b) defense that
a child will face grave risk of harm if returned because “[t]he
District Court’s application of the Convention to the facts it
has found, like the interpretation of the Convention, is subject
to de novo review”). Thus, we review the district court’s fac-
tual findings underpinning its Article 12 determination for
clear error, and its ultimate conclusion that Brianna is not now
settled in the United States de novo.

   We review the district court’s determination that it would
equitably toll the one-year filing provision set forth in Article
12 under the same standard.13 Although we generally review
a district court’s decision whether to apply equitable tolling in
cases where the facts are disputed for abuse of discretion, see,
e.g., Santa Maria v. Pacific Bell, 

, 1176 (9th
Cir. 2000), the application of this doctrine in the context of an
international treaty counsels in favor of applying a de novo
standard here. See, e.g., Cree v. Flores, 

, 768
(9th Cir. 1998) (“We review de novo the interpretation and
application of treaty language.”) (emphasis added); see also

(emphasizing “ ‘the need for uniform
   13
      Although the district court concluded that it did not need to decide the
question of the timeliness of Salmeron’s petition because it found that Bri-
anna was not “now settled,” it nevertheless made factual and credibility
determinations with respect to this question, and strongly suggested that
it would have equitably tolled the filing period if it were required to decide
the issue. In re B. del 

n.22. We agree with
the parties that we may and indeed should address the merits of Sal-
meron’s equitable tolling argument. See 

(“Given
the need to resolve these regrettably prolonged proceedings as expedi-
tiously as possible, judicial economy counsels that we address certain
issues the district court may confront on remand.”).
3466                  MENDOZA v. MIRANDA
international interpretation of the Convention’ ” (quoting 42
U.S.C. § 11601(b)(3)(B))). We recently held that equitable
tolling is available under the Hague Convention only where
“the abducting parent took steps to conceal the whereabouts
of the child from the parent seeking return and such conceal-
ment delayed the filing of the petition for return.” 

. The need for uniform interpretation of what con-
stitutes “concealment” for purposes of Article 12 tolling
weighs in favor of reviewing the factual determinations
underlying the district court’s decision to equitably toll for
clear error, see, e.g., Furnes v. Reeves, 

, 724
(11th Cir. 2004), and its ultimate conclusion that those facts
constitute concealment and thereby warrant equitable tolling,
de novo.

                       IV.    Discussion

A.     The “settled” inquiry

   [1] In determining whether a child is settled within the
meaning of Article 12, we consider a number of factors that
bear on whether the child has “significant connections to the
new country.” 51 Fed. Reg. at 10509. These factors include:
(1) the child’s age; (2) the stability and duration of the child’s
residence in the new environment; (3) whether the child
attends school or day care consistently; (4) whether the child
has friends and relatives in the new area; (5) the child’s par-
ticipation in community or extracurricular school activities,
such as team sports, youth groups, or school clubs; and (6) the
respondent’s employment and financial stability. In some cir-
cumstances, we will also consider the immigration status of
the child and the respondent. In general, this consideration
will be relevant only if there is an immediate, concrete threat
of deportation. Although all of these factors, when applicable,
may be considered in the “settled” analysis, ordinarily the
                          MENDOZA v. MIRANDA                            3467
most important is the length and stability of the child’s resi-
dence in the new environment.14

   Applying the factors set forth by the Duarte dissent, the
district court in the present case found that “Brianna has
developed significant connections to the United States.” In re
B. del 

. She has lived in the
same apartment and regularly attended school for the past five
years, has “achieved academic and interpersonal success at
every grade level,” is active in extra-curricular activities, has
many friends, and regularly visits with her mother’s family.

The district court nevertheless concluded that
Brianna is not “settled” in the United States, because neither
she nor her mother is a legal resident of this country. 

This conclusion is erroneous. Brianna’s current immi-
gration status — a status similar to that of many millions of
undocumented immigrants — cannot undermine all of the
other considerations which uniformly support a finding that
  14
      Judge Bea’s dissent in Duarte is the only time that any member of this
court has previously considered whether a child is “settled” in his new
environment within the meaning of Article 12. The Duarte majority
remanded the case for a determination on the equitable tolling question
and never reached the “settled” analysis. See 

.
Judge Bea’s dissent includes a list of factors he suggests be considered.
In establishing our list of factors, we have in the main adopted those set
forth by Judge Bea. See 

(Bea, J., dissenting). We have, however,
modified or revised a few of them.
   15
      Salmeron argues that the district court did not adopt a per se rule that
an undocumented immigrant cannot become settled. He contends that the
district court’s reasoning allows for a contrary result if a child has no
remaining ties to his home country or demonstrates that he will immi-
nently be granted legal status. The district court’s categorical language
belies this argument: “The threat of deportation is not simply an isolated
factor . . . . it is a constant danger to Brianna’s well-being, threatening to
undermine each and every connection to her community that she has
developed in the past five years.” In re B. del 

. As we explain infra, even were we to read the district court’s ruling
as Salmeron does, we would still conclude that the court afforded
improper weight to Brianna’s immigration status.
3468                  MENDOZA v. MIRANDA
she is “settled” in the United States. Indeed, only in a case in
which there is an immediate, concrete threat of removal can
immigration status constitute a significant factor with respect
to the question whether a child is “settled.”

   [2] We can see nothing in the Convention itself, in our case
law, or in the practical reality of living in this country without
documented status, to persuade us that immigration status
should ordinarily play a significant, let alone dispositive, role
in the “settled” inquiry. We first consider the text and history
of the Convention. See 

(explaining
that in interpreting a treaty the court “begin[s] with the text,”
and then looks beyond to “the purposes of the treaty, its draft-
ing history, and its post-ratification understanding”) (internal
quotation marks and citations omitted). Neither text nor his-
tory suggests that lawful immigration status is a prerequisite,
or even a factor of great significance, for a finding that a child
is “settled” in a new environment.

   [3] The text of Article 12 does not define the term “settled,”
nor “does [it] state how th[e] fact [that a child is now settled
in its new environment] is to be proved . . . .” Perez-Vera
Report ¶ 109. Article 12’s use of a relatively broad, undefined
term is consistent with the Convention drafters’ desire to
avoid “linking the determination of which country should
exercise jurisdiction over a custody dispute to . . . idiosyn-
cratic legal definitions . . . .” 

. Where
the Convention fails to define a word or phrase, courts inter-
pret the term according to its “ordinary and natural meaning”
rather than a rigid technical or legal definition. 

marks and citation omitted). Applying this method,
we have held that unlawful immigration status does not pre-
clude a finding that a child is a “habitual resident” of a coun-
try within the meaning of Article 3. See 

n.45
(“While an unlawful or precarious immigration status does
not preclude one from becoming a habitual resident under the
Convention, it prevents one from doing so rapidly.” (citing
E.M. Clive, The Concept of Habitual Residence, 1997 Jurid.
                        MENDOZA v. MIRANDA                        3469
Rev. 137, 147)). As Clive explains, “If . . . unlawful or precar-
ious residence continue[s] for long enough the ordinary user
of language would no doubt conclude that it ha[s] developed
into habitual residence.” 1997 Jurid. Rev. at 147; see also
Plyler v. Doe, 

, 227 n.22 (1982) (explaining that
“illegal entry into the country would not, under traditional
criteria, bar a person from obtaining domicile within a State”).

   [4] We apply the same reasoning in construing the term
“settled” in Article 12. As with habitual residence, if a child
has been living in a new country for a long enough period of
time, an ordinary person could conclude that the child is “now
settled” in that country, regardless of his immigration status.16
Moreover, it would be an odd result indeed if a child may be
habitually resident, but not settled, in a country in which he
does not have legal status. See, e.g., Beaumont & 

(arguing that “it would be manifestly unreason-
able, if not illogical, to demand a demonstrably higher stan-
dard [for settlement] than would, for example, be required to
indicate a change in habitual residence”). In applying both
terms, we must consider “the child’s relative attachments” to
the country, 

, and determine whether
those attachments require that the child remain in the new
environment or be returned to the prior one. By acknowledg-
ing that an undocumented child may be habitually resident
within the meaning of Article 3, then, we have already
accepted the principle that a child may remain in a place in
which he lacks legal status for the duration of custody pro-
ceedings because of his close ties to that country. For these
reasons, there is no justification in the Convention’s text or its
subsequent interpretation for holding that a child is not “set-
tled” within the meaning of Article 12 simply because he is
not lawfully present in the new country.
  16
    For example, an undocumented child that arrives as an infant and
knows no other home is plainly “settled” in this country under any ordi-
nary understanding of that term.
3470                     MENDOZA v. MIRANDA
   [5] Our second step, after considering the Convention’s text
and history, is to turn to case law. Here, too, we find no sup-
port for the view that immigration status can significantly
undermine a finding that a child is “settled” in his new envi-
ronment. Rather, prior district court cases that have concluded
that an undocumented child is not “settled” have considered
status as only one element among many pointing to a lack of
significant ties to the United States.17

   [6] Although the parties did not cite, and we were unable
to locate, an American authority in which the court considered
whether immigration status could serve as the sole basis for
holding that a child was not “settled,” there is an English case
on point. See 

(quoting Air France v.
Saks, 

, 404 (1985)) (explaining that in interpret-
ing international treaties, “the opinions of our sister signato-
ries [are] entitled to considerable weight”). In the case of “A
Child,” England’s High Court of Justice Family Division con-
sidered whether “A” was settled within the meaning of Article
   17
      See, e.g., Lopez v. Alcala, 

, 1260 (M.D. Fla.
2008) (finding children not settled where they moved around “quite a bit”
and had been at their current residence less than a year, left behind close
relationships with family in Mexico, and did not have legal status); In re
Ahumada Cabrera, 

, 1314 (S.D. Fla. 2004) (finding
child not settled where she changed schools once and residences five times
in the two and a half years she resided in the country, had no extended
support network in the United States, and both she and her mother did not
have legal status); Giampaolo v. Erneta, 

, 1281-83
(N.D. Ga. 2004) (finding child not settled where she lived in at least three
different residences and attended three different schools in her two and
half years in the United States, had no family with whom she was in con-
tact in the United States, and her mother did not have legal status); In re
Koc, 

, 152-55 (E.D.N.Y. 2001) (finding child not set-
tled where she moved three times and attended three schools in the two
and half years she resided in the country, made no close friends in the
United States, and both she and her mother did not have legal status). But
see In re Hague Child Abduction Application, 

, at *11
(D. Kan. 2008) (relying on the district court’s opinion in the present case
to find child not settled within the meaning of Article 12 because she and
her mother lacked legal status).
                     MENDOZA v. MIRANDA                     3471
12. A Child [2006] EWHC (Fam) 1229, 2006 2 F.L.R. 797,

, ¶¶ 54-57. “A” and her mother, both
United States citizens, had been living in England for five
years at the time that the father’s Hague petition was filed. 

54. For the duration of that time, the mother and child
lived in the same residence. 

found that “A” and
her mother had integrated into “a small community of sup-
portive friends and relatives by marriage” and that the child
“is now happy and making progress at her most recent
school.” 

¶ 54-55. The only countervailing factor was
that “A” and her mother did not have legal immigration status
and that they were therefore “subject in principle to a threat
of deportation.” 

¶ 56. The court concluded that despite
the mother and child’s illegal status, “A” was “settled” within
the meaning of Article 12. 

57. We conclude that, as
in “A’s” case, a child such as Brianna who has five years of
stable residence in the United States, coupled with academic
and interpersonal success here, may be “settled” within the
meaning of Article 12, despite her unlawful status.

    [7] Third, we conclude that, on a practical level, it makes
little sense to permit immigration status to serve as a determi-
native factor in the Article 12 “settled” analysis. Although
there are undoubtedly real risks posed by illegal status, the
reality is that millions of undocumented immigrants are pres-
ently living in the United States, many of whom will remain
here permanently without ever having any contact with immi-
gration authorities. The “[Department of Homeland Security]
estimates that the unauthorized immigrant population in the
United States numbered 11.6 million in January 2008.”
Michael Hoeffer, et al., Office of Immigration Statistics, Esti-
mates of the Unauthorized Immigrant Population Residing in
the United States: January 2008, 1 (2009), http://
www.dhs.gov/xlibrary/assets/statistics/~publications/
ois_ill_pe_2008.pdf. The majority of these undocumented
immigrants are long-term residents: sixty-three percent came
to this country before the year 2000. 

“Millions of
immigrants, without regard to immigration status, have regu-
3472                MENDOZA v. MIRANDA
lar employment and established homes in the United States,”
and “[e]ven with occasional spikes in the enforcement of
immigration laws, most unauthorized immigrants are unlikely
to face removal.” David B. Thornson, Custody and Contra-
dictions: Exploring Immigration Law as Federal Family Law
in the Context of Child Custody, 59 Hastings L.J. 453, 470-71
(2008). In particular, the likelihood of deportation of law-
abiding aliens — such as Brito and Brianna — is small, both
because of the sheer number of undocumented immigrants
and because the government has set a priority to deport those
with criminal records. See, e.g., U.S. Immigration and Cus-
toms Enforcement, Secure Communities: A Comprehensive
Plan to Identify and Remove Criminal Aliens (2008), http://
www.ice.gov/pi/news/factsheets/secure_communit ies.htm. In
the ordinary case, then, a child such as Brianna is at minimal
risk of removal, as is her mother. As the Supreme Court has
recognized,

    [t]o be sure, like all persons who have entered the
    United States unlawfully, [undocumented] children
    are subject to deportation. But there is no assurance
    that a child subject to deportation will ever be
    deported. An illegal entrant might be granted federal
    permission to continue to reside in this country, or
    even to become a citizen. In light of the discretionary
    federal power to grant relief from deportation, a
    State cannot realistically determine that any particu-
    lar undocumented child will in fact be deported until
    after deportation proceedings have been completed.
    It would of course be most difficult for the State to
    justify a denial of education to a child enjoying an
    inchoate federal permission to remain.

.

  Indeed, undocumented immigrants, and undocumented
children in particular, benefit from significant protections
under state and federal law. See, e.g., League of United Latin
                         MENDOZA v. MIRANDA                          3473
American Citizens v. Wilson, 

, 1255-56 (C.
D. Cal. 1997) (holding that state cannot deny public education
to children based on immigrant status); Cal. Educ. Code
§ 68130.5(a)(4) (West 2002) (permitting undocumented
immigrants to pay in-state tuition fees at California universi-
ties and community colleges)18; Tanya Broder, Overview of
Immigrant Eligibility for Federal Programs 4.3 (October
2007), available at http://www.nilc.org/immspbs/special/
pb_issues_overview_2007-10.pdf (listing available services
as including emergency Medicaid, school breakfast and lunch
programs, and access to the Special Supplemental Nutrition
Program for Women Infants and Children).

   [8] The district court’s discussion appears to acknowledge
implicitly that, to the extent that Brianna’s unlawful status
poses real risks, such risks are most likely to be suffered (if
at all) in the indefinite future. See In re B. del C.S.B., 525 F.
Supp. 2d at 1195 (discussing “the limitations [Brianna’s]
immigration status will place upon her as she matures into
adulthood” including lack of driver’s license, restricted access
to financial aid for college, poor employment prospects, and
the threat of deportation). The Convention, however, is con-
cerned with the present, and not with determining the best
interests of the child in the long term. See Hague Convention
art. 12 (providing affirmative defense where a child is “now
settled in its new environment”) (emphasis added); Matovski
v. Matovski, 

, at *8 (S.D.N.Y. 2007) (not-
ing that Article 12 is “not an invitation for courts to decide . . .
which country offers a more comfortable material existence”).
The determination of future well-being is left to the court con-
ducting custody proceedings. A petition brought under the
  18
     A recent California Court of Appeal decision held that section
68130.5 is preempted by 8 U.S.C. § 1621. Martinez v. Regents of Univer-
sity of California, 

, 545 (Cal. App. 3 Dist., 2008).
However, the California Supreme Court has granted a petition for review
of that decision. Martinez v. Regents of University of California, 

(Cal. 2008).
3474                 MENDOZA v. MIRANDA
Hague Convention, as discussed previously, merely seeks to
establish in which country that custody proceeding may take
place. Where, as here, a child has lived and thrived in her
home and school for over half of her life, and there is no rea-
son to believe that she (or her undocumented parent) will suf-
fer any imminent, negative consequences as a result of her
unlawful status, it would be contrary to the Convention’s pur-
pose of keeping a child in “the family and social environment
in which its life has developed” to rely on immigration status
as the basis for rejecting an Article 12 defense. See Perez-
Vera Report ¶ 11. Cf. 

Convention’s focus
on sociological, rather than legal, arrangements in the context
of custody rights: “the type of legal title which underlies the
exercise of [such] rights over the child matters little, since
whether or not a decision on custody exists in no way alters
the sociological realities of the problem”).

   [9] Thus, the district court erred in finding that Brianna and
her mother’s undocumented status “undermine[s] each and
every connection to her community that she has developed in
the past five years.” In re B. del 

. Immigration status cannot be determinative for pur-
poses of the “settled” inquiry if, as here, there is no imminent
threat of removal. We agree with the district court that but for
the immigration question, Brito has demonstrated that “Bri-
anna has developed significant connections to the United
States,” including a stable home and school life in which she
has consistently “achieved academic and interpersonal suc-
cess” in her five years here. 

We conclude that,
given these circumstances, Brianna is “now settled” in the
United States within the meaning of Article 12.

B.     Equitable tolling

   We turn next to the merits of Salmeron’s argument that he
is entitled to equitable tolling of the one-year period for the
filing of his Hague petition and that the Article 12 defense is
therefore inapplicable.
                     MENDOZA v. MIRANDA                     3475
   [10] Article 12 requires the return of a child, whether or not
he is “settled,” if the non-abducting parent files his Hague
petition within one year of the child’s wrongful removal or
retention. See Hague Convention art. 12. We recently held
that “equitable principles may be applied to toll the one-year
period when circumstances suggest that the abducting parent
took steps to conceal the whereabouts of the child from the
parent seeking return and such concealment delayed the filing
of the petition for return.” 

(emphasis
added). Relying on this holding, Salmeron contends that, even
if we find Brianna to be “settled,” we should nevertheless
order her returned because Brito concealed Brianna and
because Salmeron filed his petition within one year of learn-
ing of her location. We reject this argument.

   In concluding that equitable tolling is permitted under the
Convention, the Duarte court reasoned that “[l]ogic and
equity dictate that awarding an abducting parent an affirma-
tive defense if that parent hides the child from the parent
seeking return would not only encourage child abductions, but
also encourage hiding the child from the parent seeking
return.” 

. Duarte recognized, how-
ever, the “serious concerns” with its position. 

dis-
trict court explained, “the evident import of [Article 12’s one-
year period] is not so much to provide a potential plaintiff
with a reasonable time to assert any claims, as a statute of
limitations does, but rather to put some limit on the uprooting
of a settled child.” Toren v. Toren, 

, 244
(D. Mass. 1998), opinion vacated on other grounds by Toren
v. Toren, 

(1st Cir. 1999); see also Perez-Vera
Report ¶ 107. Given that equitable tolling may permit the
return of children otherwise settled in their new environment,
we adhere closely to the parameters set by Duarte so as to
ensure that the Convention’s concern over uprooting children
is not sacrificed to its aim of deterring child abductions.

  [11] Under Duarte, a court may equitably toll the one-year
period where two related conditions are met: (1) the abducting
3476                     MENDOZA v. MIRANDA
parent concealed the child and (2) that concealment caused
the petitioning parent’s filing delay. 

.
Under traditional principles, the party who seeks equitable
tolling bears the burden of proving the necessary conditions.
See Pace v. DiGuglielmo, 

, 418 (2005). Here,
Salmeron has failed to carry his burden of establishing con-
cealment. There is no evidence that Brito ever hid Brianna’s
location from Salmeron. To the contrary, the record is clear
that Salmeron knew of and sent a package to the Huntington
Beach address at which Brianna lived prior to the time that
communication was cut off, and that the address did not sub-
sequently change. Compare 

(finding
concealment where petitioner did not at first know whether
his child was in Norway or the United States); 

(finding concealment where peti-
tioner knew only that the child was in the United States but
“did not know the street address, city, or state where the Child
was living for over a year” after removal). Although Salmeron
claims, and the district court found, that he was told that Brito
and Brianna no longer lived at the Huntington Beach address,
there is no evidence that Brito ever told him that they had
moved nor that she instructed her mother to do so.19 Even
accepting that Grandmother Brito misrepresented their where-
abouts, it would be improper to impute those misrepresenta-
tions to Brito in the absence of any evidence that she
instructed her mother to lie about Brianna’s location. Addi-
tionally, Brianna has lived in the same home, at the same
address with which Salmeron was familiar, during the entire
duration of her alleged concealment. Compare In re Ahumada

(finding concealment where
respondent “frequent[ly]” moved residences); Belay v. Geta-
chew, 

, 564 (D. Md. 2003) (finding con-
cealment where Petitioner had “[no] information about the
  19
     The district court found only that Brito instructed her mother not to
disclose her new telephone number; it did not find that she told her mother
to represent that her address had changed. In re B. del C.S.B., 

at 1194 n.22.
                         MENDOZA v. MIRANDA                            3477
whereabouts of the child, above and beyond the city listed on
the plane ticket” and where Respondent removed the child
from the state when learning her father would be in the area).
For the entire period of the alleged concealment, Brianna was
enrolled under her given name at the same public elementary
school in the same school district that she attended prior to the
last communication between father and daughter in January
2003. See, e.g., 

(Bea, J., dissent-
ing) (noting in support of the conclusion that father did not
conceal children that they remained in same public school
which they had always attended). Brianna lived the life of a
normal child, regularly playing sports with her friends and
family in the public parks. She in no way lived a reclusive
existence or avoided public places or exposure. On the basis
of this evidence, we must conclude that Salmeron failed to
carry his burden of proving that Brito concealed Brianna. He
is therefore not entitled to equitable tolling.20

                           V.     Conclusion

   For the reasons set forth above, the Article 12 defense
applies. Brito met her burden of establishing that Brianna is
“now settled” in the United States, and Salmeron failed to
establish that he is entitled to equitable tolling.

   We decline to remand the case to the District Court for a
discretionary determination under Article 18 as to whether
Brianna should be returned to Mexico.21 As Salmeron asserts,
  20
      Because we find that there was no concealment, we do not consider
the second prong of the test for equitable tolling: whether concealment
was the cause of Salmeron’s delay in filing. We add, however, that we
believe Salmeron acted in good faith throughout these many years of sepa-
ration from his child, and we hope that some arrangement will be arrived
at, regardless of any custody award, that will enable both parents to see
and visit with their child on a reasonable number of occasions.
   21
      See Hague Convention art. 18 (“The provisions of this Chapter do not
limit the power of a judicial or administrative authority to order the return
of the child at any time.”).
3478                 MENDOZA v. MIRANDA
the existing record contains sufficient factual findings to sup-
port a decision by this court without remand; and
Mozes counsels us to address whatever issues we may dispose
of, “[g]iven the need to resolve these regrettably prolonged
proceedings as expeditiously as possible . . . .” 

. Where, as here, the child at issue is settled in
her new environment and has been so for years; and where,
as here, there was no showing of “concealment” such that the
reprehensibility of the abducting parent’s conduct should
trump the finding that the child is “settled,” we can see no
reason justifying an exercise of discretion under Article 18 to
order Brianna’s return to Mexico.

   We emphasize once more that under the Hague Conven-
tion, our decision has a limited purpose and effect: it autho-
rizes the initiation of custody proceedings in the United
States, and it establishes that Brianna will remain where she
is already living throughout the duration of those proceedings.
The final determination of where Brianna will live in the
future, and in whose custody, will be resolved through those
proceedings, and not through this one. In California, as in
most states, that determination will be made by giving the
foremost consideration to Brianna’s best interests. Cal. Fam.
Code § 3011.

  [12] We therefore REVERSE the district court’s decision
and DENY Salmeron’s petition under the Hague Convention.