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MOLT PATTERNS, AGE CRITERIA, AND MOLT-BREEDING
DYNAMICS IN AMERICAN SAMOAN LANDBIRDS
PETER PYLE,
1,5
KEEGAN TRANQUILLO,
2
KIMIKO KAYANO,
3
AND NICOLE ARCILLA
3,4
ABSTRACT.—We examined 135 specimens and analyzed 1,735 captures of indigenous American Samoan landbirds, of
nine target species in seven families, to document molt patterns, assess the extent of molt-breeding overlap, and present
criteria to determine age. Preformative molts varied from absent to complete, and there was no confirmed evidence for
prealternate molts. Molt strategies, age-determination criteria, and remigial replacement sequences were largely consistent
with those of other temperate and tropical bird species within the same families. Suspended and/or arrested molts were
recorded in seven species and staffelmauser or stepwise molt in two species, including the first report in a passerine. Our
data suggest that staffelmauser and suspension of molt in passerines may share a common underlying mechanism. Despite
broad overlap of breeding and molting seasons at the population level, we observed little evidence of molt-breeding overlap
at the individual level. We suggest that molt and accompanying restoration processes may take precedence over breeding,
as indicated by well-defined molting seasons despite apparent year-round or bi-modal breeding in some of our species.
Tropical landbird species appear to be capable of suspending molt to breed when environmental conditions shift to facilitate
successful reproduction. Received 5 February 2015. Accepted 26 July 2015.
Key words: age criteria, American Samoa, landbird, molt sequence, molt suspension, staffelmauser.
Molt strategies in tropical landbirds remain
poorly known (Ryder and Wolfe 2009, Wolfe and
Pyle 2012) despite some recent descriptions of molt
patterns in certain tropical avifaunas or families
(e.g., Pyle et al. 2004, Wolfe et al. 2009). In the
tropical and subtropical Pacific Basin, molt pat-
terns and age-determination criteria have only been
described for a few endemic Hawaiian landbird
species and those species breeding on Saipan,
Northern Marianas Islands (Freed and Cann 2009,
Radley et al. 2011). Breeding in tropical areas can
occur year-round or can respond opportunistically
to aseasonal interannual rainfall patterns, which in
turn can result in more-complex molting regimes
than are found in species that breed during succinct
seasons in temperate or boreal regions. Molts in
tropical areas, for example, may include an
increased incidence of molt-breeding overlap or
suspension of molt for breeding (Radley et al. 2011,
Freed and Cann 2012, Johnson et al. 2012). Data on
molting patterns from additional tropical regions
are needed to better understand complex interac-
tions between molting and breeding regimes.
In 2012, the Institute for Bird Populations (IBP)
initiated a Tropical Monitoring Avian Productivity
and Survivorship (TMAPS) program in American
Samoa, where practically nothing was known of
molt and breeding patterns or age-determination
criteria for landbirds. Similar to the North Amer-
ican MAPS program, TMAPS utilizes data collect-
ed on captured landbirds at mist-netting stations to
understand demographic parameters useful in
implementing habitat conservation and manage-
ment strategies (DeSante et al. 1995, Saracco et al.
2012). Accurate categorization of age, which relies
on molt strategies and plumage development, is
necessary to estimate vital rates and population
demography using TMAPS data. Therefore, we
initially operated TMAPS stations every month
from August 2012 to August 2013, in order to
assess breeding seasonality, molt patterns, and
age-determination criteria throughout each spe-
cies’ complete annual cycle. Based on these data,
we identified peak breeding and molting seasons
and identified November–March as the optimal
TMAPS period to capture the breeding season of
most landbirds in American Samoa (Pyle et al.
2014). Here, we present molting strategies and age
and sex criteria for nine landbird species in-
digenous to American Samoa (Table 1), and we
assess the extent to which each species overlaps or
separates breeding periods from those of the annual
prebasic molt.
METHODS
A total of 16 TMAPS stations were operated on
Tutuila (14u179S, 170u419W) and Ta’u (14u149S,
169u289W) islands, American Samoa, during all or
1
The Institute for Bird Populations, P.O. Box 1346, Point
Reyes Station, CA 94956, USA.
2
P.O. Box 181, Virginville, PA 19564, USA.
3
Department of Marine and Wildlife Resources, P.O.
Box 3730, Pago Pago, American Samoa 96799.
4
Current address: Department of Biodiversity, Earth and
Environmental Science, Drexel University, Philadelphia PA
19104, USA.
5
Corresponding author; e-mail: ppyle@birdpop.org
The Wilson Journal of Ornithology 128(1):56–69, 2016
56
parts of August 2012–August 2013, December
2013–March 2014, and December 2014–March
2015. Each station consisted of 10 mist nets
operated for ,6 hrs per day, for up to 3 consecutive
days (a “pulse”), once per month, following IBP
protocols for stations in tropical regions (DeSante
et al. 2005). On Tutuila, six stations were operated
during most of the above months, although four
stations had to be discontinued and replaced by
other stations in 2012 or early 2013 because of poor
capture rates or logistical considerations. Twelve
stations (six on Tutuila and six on Ta’u) were then
operated monthly during December 2013–March
2014 and December 2014–March 2015. For each
captured or recaptured bird, complete data were
obtained according to MAPS protocols (DeSante et
al. 2012), and wing chord, tail, and bill measures
were obtained following the methods of Pyle
(1997). Most captured birds were photographed,
including images of body, spread-wing, and
spread-tail, to confirm age and molting status.
Molt patterns and criteria to determine age and
sex were developed initially based on examina-
tion of specimens by PP (see Acknowledgments
for collection locations) along with a synthesis of
information from the literature on American
Samoan and other congeneric species (Mayr
1933, 1941, 1942; Amadon 1942, 1943a,b; Banks
1984; Higgins 1999; Higgins et al. 2001, 2006;
Radley et al. 2011). Each specimen was evaluated
for molting status, extent of previous molts, age,
and sex (as supplemented by information on
specimen labels), and wing chord and other
measures were obtained following methods of
Pyle (1997). A preliminary manual was developed
(Pyle 2013b) based on these specimen data that was
then updated and refined based on the first year of
capture data collection.
To classify birds to age, we used the “WRP”
age-coding system (Wolfe et al. 2010, Johnson et
al. 2011) developed for use in tropical regions,
where calendar-based age-coding is impractical.
The WRP system codes age-groups according to
molt cycles and plumages following the termi-
nology of Humphrey and Parkes (1959) and
Howell et al. (2003). WRP age codes indicate
whether or not a bird is actively molting and
categorizes plumages based on the previous
prebasic or inserted molts. WRP codes used here
include: first cycle, juvenile plumage (FCJ); first
cycle, undergoing the preformative molt (FPF);
first cycle, formative plumage (FPF); plumage
after (older than) juvenile (FAJ); second cycle,
undergoing the second prebasic molt (SPB);
second cycle, basic plumage (SCB); third cycle,
undergoing the third prebasic molt (TPB); de-
finitive cycle, basic plumage (DCB); definitive
cycle, undergoing the definitive prebasic molt
(DPB); and after (older than) second cycle (SAB);
see Johnson et al. (2011) and Pyle et al. (2015) for
tables summarizing these codes. Additional age
categories and codes, indicating unknown molt
and/or plumage status, were used occasionally;
these include non-molting individuals of unknown
cycle and plumage (UCU), individuals undergo-
ing an unknown molt (UPU), individuals un-
dergoing either the second or definitive prebasic
molt (UPB), and individuals of unknown molt and
plumage status (UUU). These unknown codes
were used when age and/or molt status could not
be determined, often as a result of escape prior to
all data being recorded; UPB was also used for
TABLE 1. Molt extents and WRP groupings for nine native Samoan landbird species.
Molt extent WRP
Common name Scientific name Preformative Prebasic group
1
Purple-capped Fruit-Dove (PCFD) Ptilinopus porphyraceus Incomplete to Complete Incomplete to Complete 1
Blue-crowned Lory (BCLO) Vini australis Partial Complete 2
White-rumped Swiftlet (WRSW) Aerodramus spodiopygia Partial Incomplete to Complete 3
Collared Kingfisher (COLK) Todiramphus chloris Absent Complete 4
Samoan Shrikebill (SASH) Clytorhynchus powelli
2
Partial Incomplete to Complete 3
Cardinal Honeyeater (CAHO) Myzomela cardinalis Incomplete Incomplete to Complete 3
Wattled Honeyeater (WAHO) Foulehaio carunculata Partial Incomplete to Complete 3
Samoan Starling (SAST) Aplonis atrifusca Partial Incomplete to Complete 3
Polynesian Starling (POST) Aplonis tabuensis Partial Complete 2
1
WRP Groups have specific combinations of acceptable WRP age codes (see text and Johnson et al. 2011 for abbreviations): Group 1 5FCJ, FPF, FCF, SPB,
FAJ, UPB, DCB, DPB; Group 2 5FCJ, FPF, FCF, SPB, UPB, DCB, DPB; Group 3 5FCJ, SPB, UPB, DCB, DPB; Group 4 5FCJ, SPB, SCB, TPB, UPB, DCB,
DPB, SAB. All groups also have additional acceptable “unknown codes” (UPU, UCU, and UUU) which should be avoided if possible (see text).
2
Samoan Shrikebill is split from Fiji Shrikebill (C. vitensis) following Pratt (2010).
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
57
birds just completing final feather growth of either
the second or definitive prebasic molt. Depending
on extents of the preformative and definitive
prebasic molts in a species, acceptable WRP
codes were derived for each species (Table 1;
see also Pyle et al. 2015).
Primaries were numbered from innermost (p1)
to outermost (p10), tertials were numbered from
innermost (t1) to outermost (t3), other secondaries
were numbered from outermost (s1) to innermost
(s6, s7, or s8, depending on the species), and
rectrices were numbered from innermost (r1) to
outermost (r5 or r6, depending on the species) on
each side of the tail. For birds captured at TMAPS
stations, data on the progress and sequence of
active flight-feather molt were obtained follow-
ing the recommendations of Rohwer (2008).
Each primary was scored as new (10), missing
(1), growing (scored 1–9 to the nearest 10%of full
growth), or old (0), resulting in active molt scores
between 1 (one primary dropped) and 100 (primary
molt completed and secondary molt completing),
and these scores were used to indicate overall molt
progress. These data were also used to determine
precise molt sequence, including initiation (nodes)
and completion (termini) points, among primaries,
tertials, and adjacent secondaries. Non-molting
birds that had suspended or arrested molt of
primaries or secondaries were also scored.
We considered captured birds as actively
breeding if either a brood patch or a cloacal pro-
tuberance (Pyle 1997) was scored as “partial” or
“full” following DeSante et al. (2012; scores 2 or
3). Recaptures of the same individual from separate
pulses were included in analyses of molt and
breeding seasonality, but only the first capture of an
individual within a pulse was included. Measure-
ment data were included only from the first capture
of an individual.
RESULTS
Our analyses included a total of 135 specimens
and 1,735 captures of our nine target species
(Table 1). Of the 1,735 captures, 535 (31%) were
of birds undergoing active remigial (primary and/
or secondary) molt and 231 (13%)wereof
individuals in active breeding condition. All nine
species have 10 primaries. Unless otherwise
indicated, prebasic or preformative molt sequence
progressed from a node at the innermost (p1) to
a terminus at the outermost (p10) primary, and
sequence among secondaries proceeded from
a node at either the innermost tertial (t1) distally
or the second tertial (t2) bilaterally, followed by
a node at the outermost secondary (s1) proximally.
The terminal secondary replaced in most species
was either s6 or s5. None of our study species
showed evidence confirming prealternate molts, so
acceptable age determination and coding was
based on extents of preformative molts in the first
cycle and prebasic molts in second and definitive
cycles. Four species groups were identified accord-
ing to molting patterns and acceptable WRP coding
choices (Table 1; see also Pyle et al. 2015).
The following accounts summarize molt, breed-
ing status, and age-determination criteria for each
species. Measurement ranges (mm) from the
literature (cited above), specimens, and captured
birds combined, are present based on mean
62*SD, to eliminate outliers and to represent
,95%of the sample (see Pyle 1997). Age criteria
common to all species include narrower and more
tapered juvenile primaries and rectrices in FCJs
and FCFs (of species with incomplete preformative
molts) than in DCBs and older age groups (Pyle
1997), and molt clines among the secondaries
in DCBs but not FCFs of species with incom-
plete preformative molts (Pyle 2008), reflecting
previous protracted replacement as is typical in
tropical passerines.
Species Accounts
Purple-capped Fruit Dove.—(Ptilinopus pory-
phyraceus; n519 specimens and 36 captures).
Both the preformative and the definitive prebasic
molts can be incomplete or complete, resulting in
acceptable WRP codes for species Group 1
(Table 1). Active preformative (n58) and
prebasic (n59) molts were recorded throughout
the year (all months except Apr, Aug, and Sept),
without any apparent seasonal peaks in timing.
Secondaries were recorded molting proximally
from nodes at s5 as well as s1 (Table 2B). One
bird commenced tertial molt with t2 (Table 2A)
whereas none showed evidence of distal replace-
ment from t1. Evidence of staffelmauser or step-
wise molt (Stresemann and Stresemann 1966, Pyle
2006) was recorded in 13 of 38 individuals (e.g.,
Table 2A, Fig. 1B). Only three birds were captured
in breeding condition, in December, January, and
March, and none of these were simultaneously
undergoing active molt.
Juvenile (FCJ) Purple-capped Fruit-Doves lack
purple caps, show pale-tipped upperpart feathers
and remiges, and have blunter tips to the notched
juvenile outer primaries than in subsequent
58
THE WILSON JOURNAL OF ORNITHOLOGY NVol. 128, No. 1, March 2016
plumages (Fig. 1). The highly modified forma-
tive or basic p10 likely results in acoustic
signaling during aerial courtship. These juvenile
plumage and primary-shape traits were also found
in P. roseicapilla (Radley et al. 2011) and
P. perousii (Pyle 2013b) and may be common to
the genus Ptilinopus. Following complete molts,
FCF is not distinguishable from DCB, and birds
were aged FAJ. Individuals with retained juvenile
primaries or secondaries, after suspended or
TABLE 2. Captures of American Samoan bird species showing variation in replacement sequences among secondaries
and primaries.
1
Secondaries Primaries
Species Band Date t1 t2 t3 s8 s7 s6 s5 s4 s3 s2 s1 p1 p2 p3 p4 p5 p6 p7 p8 p9 p10
A PCFD 085416900 8 Jan 13 O N OOOOO8 ONON7 OOONNN3 O
B PCFD 085416879 5 Jul 13 X N NOOXNOOOONNN N8 XOOOO
C BCLO 135230494 7 Feb 14 N N N - O 9 N N 7 2 O O 7 N N S N N N 8 X
D COLK 135230006 8 Aug 12 N N NNN5 O9 NNNNNNNNNNNN8
E COLK 135230146 17 Jun 13 N N NNNN5 3 NNNNNNNNNNNN6
F SASH 184130506 9 Jan 14 O 7 2 - - O OOOOO7 4 XOOOOOOO
G SASH 184130572 22 Feb 14 O 8 X - - O OOOOOX6 5 1 O OOOOO
H SASH 184130591 3 Mar 14 O 7 3 - - O OOOOO1 8 4 XOOOOOO
I SASH 184130509 29 Dec 14 N N N - - O ONNNNNNNNNNNNOO
J CAHO 252158908 27 Feb 12 N N N - - O OOONNNNNNNNNNOO
K WAHO 256191605 22 Mar 13 N N N - - 9 6 N N N N N N NNNNNN9 7
L WAHO 184130522 28 Dec 13 O X O - - 8 NOOOO5 1 XOOOOOOO
M SAST 084423034 14 Dec 13 N N N - - O OONNNNNNNNNNNNN
1
See Table 1 for four-letter species codes and Rowher (2008) forpresentation and interpretation of molt data;O 5old feather, N 5new feather, X 5missing fe ather,
and numbers represent tenths of a growing feather. A dash (-) indicates that this secondary is not present in the species. See text for discussion of eachlineofdata.
FIG. 1. Shapes of juvenile (left, band # 178375730 captured 19 Mar 2013) and basic (right, band # 085416872 captured
21 Jan 2013) outer primaries (p10) in Purple-capped Fruit-Dove to assist with age determinations. Note also the suspended
molt between p7 and p8 on the right-hand image (B), part of a staffelmauser molting pattern, and allowing age-code
assignment of DCB (see text).
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
59
arrested preformative molts, were aged SCB, and
those with retained formative or basic feathers as
part of staffelmauser patterns were aged DCB.
Among post-juvenile birds, males can be distin-
guished from females by showing brighter and
more-extensive magenta on the crown, bluer-
tinged napes, and broader and more complete
yellow tips to the rectrices. Sexes (both islands
combined) differentiated moderately by wing
chord: R(n36) 124–137 and =(n25) 132–146
mm, with FCJs and FCFs falling in the bottom
portions of each range.
Blue-crowned Lory.—(Vini australis; n515
specimens and 14 captures). The preformative molt
is partial, including body feathers but no wing or
tail feathers, and the definitive prebasic molt is
complete, resulting in acceptable WRP codes for
species Group 2 (Table 1). Active prebasic molt
was recorded in August–February to indicate
a protracted molting season during this period;
Banks (1984) also noted peak molting in Decem-
ber–January. Molting patterns indicated bilateral
replacement from nodes at p5 and s5 and that molt
could be suspended for breeding after p5 had been
dropped (e.g., Table 2C). Suspension occasionally
occurred elsewhere within remigial tracts; overall
suspended molt was present in four of 15 SCB or
older birds in which this could be assessed. A node
at t2 was confirmed for one bird, whereas none
showed a node at t1. No individuals were captured
in breeding condition; based on gonadal develop-
ment in collected specimens, Banks (1984) noted
breeding condition in June but little to none in
December–January, suggesting more-active breed-
ing in February–November, followed by active
molting.
Juvenile plumage (FCJ) is undescribed in Blue-
crowned Lory, but it may have reduced extents of
duller blue in the crown and red in the underparts,
darker bill and eye color, and duller leg color, as in
other parakeets of the genus Vini (Higgins 1999).
Crown and underpart coloration averages duller in
FCFs and females than in DCBs and males, but
there is overlap among age/sex groups. Definitive
outer primaries may have more distinct notches to
the tips than juvenal outer primaries. These criteria
and molt clines (Pyle 2013a) can be used to
distinguish FCFs and DCBs, after which sex
determination can be attempted by plumage
brightness. Sexes of this species on Ta’u appear
relatively monomorphic: wing chord R(n23)
102–113, =(n25) 104–117; tail length R(n19)
61–67, =(n19) 61–69 mm.
White-rumped Swiftlet.—(Aerodramus spodio-
pygia; n56 specimens and 18 captures). The
preformative molt is partial, including body
feathers but not wing feathers, and the prebasic
molt is incomplete to complete, resulting in
acceptable WRP codes for species Group 3
(Table 1). Two specimens captured in December
had initiated prebasic molt, and two specimens
collected in March and one capture in May were
completing this molt, suggesting a molting season
of November–May (see also Banks 1984). Three
swifts captured in December had suspended the
prebasic molt after p1–p3 (but no secondaries) had
been replaced. This compares with nine DCBs
showing evidence of complete uninterrupted molts.
No individuals were captured in breeding condition
but information from other specimens (Banks
1984) and our data suggest that breeding occurs
during March–October, followed by molting.
Juvenile (FCJ) White-rumped Swiftlets show
narrow buff fringes to upperpart feathers, second-
aries, and inner primaries when fresh. There may
also be molt limits visible between replaced
scapulars and retained wing coverts in FCFs but
not DCBs. SCB and SAB can be coded for birds
that have suspended or arrested second or later
prebasic molts, respectively. Insufficient data
were available to assess sex-specific biometrics;
18 captures (both islands combined) of unknown
sex had wing chord 107–120 and tail length 47–53
mm, with no evidence of a bimodal distribution
suggesting sex-specific dimorphism.
Collared Kingfisher.—(Todiramphus chloris; n
520 specimens and 206 captures). The preforma-
tive molt is absent and the definitive prebasic molt is
complete, resulting in acceptable WRP codes for
species Group 4 (Table 1). Ten individuals showed
a node at t2 and in nine individuals t1 was nodal. The
terminal secondary was either s5 (n53 captures), or
s6 (n52; Table 2D–E). Active prebasic molt within
the population commenced in December and
completed in August (Fig. 2A). No evidence of
suspended or incomplete molts was observed. None
of our captures had developed brood patches or
cloacal protuberances, but specimen evidence
(Banks 1984) indicates peak gonadal activity in
October–November, a period during which no birds
were recorded molting (Fig. 2A).
As in Saipan (Radley et al. 2011), FCJ Collared
Kingfishers show white fringing to the upperwing
secondary coverts and thin dusky mottling to the
breast when fresh. Females have darker to bright
green backs and turquoise flight feathers and males
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THE WILSON JOURNAL OF ORNITHOLOGY NVol. 128, No. 1, March 2016
have turquoise to blue backs and pale to bright blue
flight feathers, in both sexes averaging brighter and
bluer in DCBs than in FCJs. Wing chord was not
useful for sex determinations, averaging slightly
larger in females than males and slightly larger on
Ta’u than on Tutuila: R(n88) 90–100 and =(n129)
89–99 mm on Tutuila; R(n40) 92–100 and male =
(n90) 91–99 mm on Ta’u.
Samoan Shrikebill.—(Clytorhynchus powelli;
n510 specimens and 55 captures); we follow
Pratt (2010) in considering Samoan Shrikebill
a separate species from Fiji Shrikebill (C. vitiensis).
The preformative molt is partial and the prebasic
molt is incomplete to complete, resulting in accept-
able WRP codes for species Group 3 (Table 1). The
preformative molt includes body feathers and
upperwing lesser coverts, most to all median
coverts, and 1–6 inner greater coverts but no other
wing or tail feathers. Nodes among the inner
primaries varied, with typical sequence (p1 nodal)
recorded for one DPB and two SPB individuals
(e.g., Table 2F) and a node at p2 recorded for five
FIG. 2. Proportion of captured adult (SPB, SCB, DCB, DPB, UPB, or SAB; see text) individuals breeding and molting
during each month, and mean primary replacement scores for birds in active molt, for five species of indigenous American
Samoan landbirds. Sample sizes of captured birds are in parentheses below each month.
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
61
individuals (three SPBs and two DPBs; e.g.,
Table 2G–H, Fig. 3). Among tertials, a node at
t2 was recorded for 11 individuals (e.g., Table
2F–H), whereas no individual showed t1 nodal.
In four captures s6 was terminal, although this
feather was growing and only slightly shorter (by
0.1–0.2 feather lengths) than s5 on three of these
captures. An actively breeding SAB female was
captured that had suspended or arrested molt,
retaining basic p9–p10 and s5–s6 on both wings
(Table 2I) and a second SAB had retained the
basic p10 on both wings; this compares with 26
DCBs that had undergone uninterrupted complete
molts. Twenty of 38 birds captured in December–
March were undergoing active prebasic molt, with
molt generally commencing in December–Janu-
ary and completing in March or later, although
two UPB individuals had nearly completed molt
by mid-January. Mayr (1933) also assumed active
molt occurred in January–April based on speci-
men evidence. Seven females and two males were
captured in active breeding condition, all during
December or early January, and none of which
were simultaneously molting. These data indicate
that breeding probably occurs primarily in No-
vember–January, followed by the prebasic molt.
Juvenile (FCJ) Samoan Shrikebills resemble
birds in later plumages except for having rufous-
fringed wing coverts. FCFs can be identified by
thinner and more worn outer primaries and rectrices
(see above) as well as molt limits in the upperwing
coverts, the retained juvenile greater coverts
fringed rufous when fresh, whereas DCBs have
uniform and glossier wing coverts. SCB and SAB
can be coded for birds that have suspended
or arrested the second or later prebasic molts,
respectively. Sexes are alike in plumage and differ
only slightly in average wing chord length:
R(n16) 87–90 and =(n12) 88–93 mm.
Cardinal Honeyeater.—(Myzomela cardinalis;
n516 specimens and 106 captures). The
preformative molt is incomplete and the prebasic
molt is incomplete to complete, resulting in
acceptable WRP codes for species Group 3
(Table 1). The preformative molt often includes
all feathers except the inner 2–6 primary coverts
(Fig. 4). Among tertials, a node at t2 occurred in 8
individuals, whereas no individual showed t1
nodal. During prebasic molts, s6 was terminal in
10 individuals and s5 in three individuals; during
the preformative molt, s6 was terminal in five
individuals and s5 in no individuals. At least five of
37 individuals showed evidence that the definitive
prebasic molt had suspended or arrested before all
primaries or secondaries had been replaced (e.g.,
Table 2J). Active prebasic molt within the popu-
lation commenced in December and completed in
March (Fig. 2B), whereas birds in active breeding
condition were recorded in April to December,
none of which were simultaneously in active molt.
Body molt occurred more extensively around the
year than in other Samoan landbirds, suggesting the
possibility of a prealternate molt, although there
was no indication of a distinct inserted molting
season. Active preformative molt of primaries was
recorded throughout the year, and molt scores
FIG. 3. Samoan Shrikebill (band # 184130591 captured
3 Mar 2014) showing a molt-commencement node at p2 as
opposed to p1, with p1 and p4 dropped and p2 longer than
p3 (primary scores for this bird are shown in Table 2H).
Bilateral replacement from within the primary tract is rare
in passerines (see text).
FIG. 4. Formative-plumage (FCF) Cardinal Honeyeater
(band # 252158960 captured 23 Mar 2013) showing
retention of inner 5 juvenile primary coverts. The browner
and more-worn condition of these coverts allows age-
determination; older individuals (DCBs) have uniform
primary coverts and primaries.
62
THE WILSON JOURNAL OF ORNITHOLOGY NVol. 128, No. 1, March 2016
indicated a pattern of protracted molt, many FPFs
molting inner primaries in December–March and
outer primaries in June–December.
Juvenile (FCJ) Cardinal Honeyeaters of both
sexes show olive-gray to brown plumage without
red feathering. DCB females have olive-fringed,
gray body and wing feathers with incomplete
reddish feathering in the head, back, rump, and
uppertail coverts, and DCB males show bright red
body plumage and black wings and tail. FCFs can
be identified by having retained inner primary
coverts which are browner than the remainder of
the wing feathers (Fig. 4); FPFs and FCFs can be
sexed by the color of formative feathers, gray and
reddish in females or black and bright red in
males. SCB and SAB can be coded for birds that
have suspended or arrested the second or later
prebasic molts, respectively. Wing chord is useful
for sex determinations, averaging larger in males
than in females on Tutuila: R(n29) 55–64 and
=(n81) 62–72 mm, with FCJs and FCFs falling in
the bottom portions of each range.
Wattled Honeyeater.—(Foulehaio carunculata;
n511 specimens and 989 captures). The
preformative molt is partial and the prebasic molt
is incomplete to complete, resulting in acceptable
WRP codes for species Group 3 (Table 1). The
preformative molt includes body feathers and
upperwing lesser coverts, most to all median
coverts, no to all inner greater coverts, sometimes
(during about 22%of preformative molts) 1–3
tertials, and occasionally (during about 5%of
preformative molts) 1–6 central rectrices (among
r1–r3). Among tertials, a node at t2 was recorded
for 133 individuals (during 32 preformative molts
and 101 prebasic molts), whereas 17 individuals
(during four preformative molts and 13 prebasic
molts) showed a node at t1, and among second-
aries, s6 was terminal in 109 individuals, s5 was
terminal in 10 individuals (e.g., Table 2K), and
seven individuals had s5 and s6 growing at the
same length. Thirty-nine individuals showed
evidence of incomplete or suspended prebasic
molts (e.g., Fig. 5; 10 second prebasic and 29
definitive prebasic molts), whereas 480 individuals
lacked evidence of suspended or incomplete
prebasic molts. Notably, 29 of these 39 individuals
that had suspended molt were females (19 of which
were actively breeding), four were of unknown sex,
and only six individuals that had suspended or
arrested molt were males. Four females and one
male showed evidence that retained s5 and/or s6
from one molt could be among the first feathers
replaced during the subsequent molt (Table 2L;
Fig. 6).
A distinct molting season occurred within the
population from November to April (according with
the observations of Mayr 1933 and Banks 1984),
whereas breeding appeared to occur at low levels
throughout the year, with possible bimodal peaks
in May–July and October–November (Fig. 2C).
FIG. 5. Wattled Honeyeater (band # 121243359
captured 7 Jan 2014) with evidence of suspended molt;
p3–p5 are new, following suspension after p1–p2 had been
replaced, and suspending again after p5 had been replaced.
The left wing showed a similar pattern except that p2–p5
had been replaced after and before suspensions. Outer
primaries are basic so this bird was age-coded SAB.
FIG. 6. Wattled Honeyeater (band # 184130549
captured 7 Feb 2014) with growing s5 and old s6, during
commencement of a prebasic molt. This molt condition was
symmetrical on both wings, and indicates that arrested
feathers during one molt can be the first replaced in
a subsequent molt in passerines, similar to staffelmauser
molt patterns in non-passerines. Four other Wattled
Honeyeaters (e.g., Table 2L) and two Samoan Starlings
also showed this pattern.
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
63
Twenty-two actively breeding individuals were
also undergoing active primary molt, representing
11.4%of actively breeding birds captured and
6.4%of individuals either actively breeding or
molting. These birds had only partial brood
patches (n55) or cloacal protuberances
(n517) and primary molt scores either ,12 or
.89, indicating developing or receding reproduc-
tive conditions during completion or initiation of
primary molt, respectively.
Juvenile (FCJ) Wattled Honeyeaters resemble
birds in later plumages except for having more
distinct pale edging to the wing coverts. FCFs were
identified by molt limits in the upperwing coverts,
and among the tertials and rectrices in some birds
(see above), the retained juvenile feathers being
contrastingly worn as compared with replaced
formative feathers, whereas DCBs showed uni-
form, glossier and broader wing and tail feathers.
SCB and SAB were coded for birds that had
suspended or arrested the second or later prebasic
molts, respectively. Sexes are alike in plumage, but
our data indicate that all birds on both Tutuila and
Ta’u can be sexed by wing chord: R(n198) 85–95
and =(n296) 96–107 mm, with no substantial
difference in wing lengths between the two
islands.
Samoan Starling.—(Aplonis atrifusca; n517
specimens and 245 captures). The preformative
molt is partial and the prebasic molt is incomplete
to complete, resulting in acceptable WRP codes
for species Group 3 (Table 1). The preformative
molt includes body feathers and upperwing lesser
coverts, most to all median coverts, no to some
inner greater coverts, and sometimes (during about
10%of preformative molts) 1–2 tertials (among
s8–s9) and/or 1–4 central rectrices (r1–r2). The
prebasic molt appeared to be protracted, beginning
in June–August and completing in December–
March (Fig. 2D). Seven individuals showed t2
nodal, whereas no individuals showed t1 nodal,
and a terminus at s6 was observed in 34 individuals
and one at s5 in nine individuals. Seventeen
SAB and three SCB individuals showed evidence
of incomplete or suspended prebasic molts (e.g.,
Table 2M), whereas 82 individuals lacked evi-
dence of suspended or incomplete molts.
One SAB female and one SAB male showed
evidence that retained s5 and/or s6 from one molt
could be among the first feathers replaced during the
subsequent molt, as noted for Wattled Honeyeater
(see Table 2L; Fig. 6), and one DPB female was
captured undergoing staffelmauser-like replacement
of primaries, with p2 and p7 growing simulta-
neously on both wings (Fig. 7). Only six captured
birds were in active breeding condition, one in
January, three in May, and two in July (Fig. 2D),
none of which were also undergoing active molt;
however, an additional 11 adult females were
captured with receding brood patches in November
and early December. Our data along with those of
Banks (1984) suggest a primary breeding season of
May–November with lower-level breeding in
December–April.
Juvenile (FCJ) Samoan Starlings resemble birds
in later plumages except body feathers and wing
coverts are browner and upperpart feathers may
have slightly wider pale fringing. FCFs were
identified by molt limits in the upperwing coverts,
and occasionally among the tertials and rectrices
(see above), the retained juvenile feathers con-
trastingly brown and worn as compared with
replaced formative feathers. DCBs showed uni-
form, glossier and broader wing and tail feathers.
SCB and SAB were coded for birds that had
suspended or arrested the second or later prebasic
molts, respectively. The length of the reduced
outer primary (p10) varied substantially, ranging
from 4 mm shorter to 9 mm longer than the
longest primary covert, but we found no relation-
ship between length or shape of p10 and age, sex,
or island of capture.
FIG. 7. Samoan Starling (band # 84423051 captured 27
Feb 2015) with growing p2 and p7 (symmetrically on both
wings) and showing molt patterns among primaries and
secondaries indicating staffelmauser or stepwise molt.
Together with other Samoan Starlings as well as Wattled
Honeyeaters that have begun prebasic molts with retained
inner secondaries (e.g., s5 and s6; see Fig. 6, Table 2L), this
suggests that staffelmauser in non-passerines and suspen-
sion for molt in passerines may share a common under-
lying mechanism.
64
THE WILSON JOURNAL OF ORNITHOLOGY NVol. 128, No. 1, March 2016
In FCFs and DCBs, males averaged glossier than
females but there was substantial overlap between
the age-sex groups in this character. In females,
mean length of glossy tips was 6.0 for nape feathers
(95%CI 4.3–7.6, n539), 4.8 for back feathers
(3.1–6.3; n530), and 4.0 for breast feathers
(2.3–5.5; n531), whereas respective values for
males were 7.1 (5.5–8.7; n536), 5.3 (3.8–5.8;
n530), and 5.1 (3.4–6.8; n533). Bill size was
also larger in males (means: from nare to tip 22.2,
depth at nare 10.4, and width at nare 9.3; n559–
61) than in females (21.0, 9.7, and 8.8, respective-
ly; n557–62) with ,50%overlap in each sex.
Our data indicate that wing chord, however,
could be used to sex all birds on each island: R
(n23) 132–142 and =(n41) 145–154 mm on
Tutuila; R(n49) 136–145 and =(n85) 148–157 mm
on Ta’u.
Polynesian Starling.—(Aplonis tabuensis; n5
21 specimens and 66 captures). The preformative
molt is partial and the prebasic molt is complete,
resulting in acceptable WRP codes for species
Group 2 (Table 1). The preformative molt includes
most to all body feathers and upperwing lesser
coverts, some to most median coverts, no to some
inner greater coverts, and rarely 1–2 tertials, but no
other remiges or rectrices. A node at t2 was
recorded for one individual, whereas no individuals
showed a node at t1, and a terminus at s6 was
shown by six individuals and a terminus at s5 in one
individual. No individuals showed evidence of
incomplete or suspended prebasic molts. Molting
appeared to occur primarily in November–Febru-
ary. Only three captured birds were in active
breeding condition, males in December with partial
cloacal protuberances (Fig. 2E), none of which
were undergoing active molt.
Polynesian Starlings differ in plumage by
island. DCBs show blackish unstreaked under-
parts on Ta’u and dark gray underparts with pale
streaks on Tutuila.
Juveniles (FCJs) show body plumage that is
paler brown than FCFs, which are in turn browner
than in DCBs. We also identified FCFs by molt
limits between paler brown juvenile and darker
brown formative upperwing coverts, whereas
DCBs showed uniform, glossier and broader wing
and tail feathers. Head plumage appeared to be
glossier in DCBs than in FCFs and glossier in
males than in females, but measurements of gloss
tips did not differ by age and sex as in Samoan
Starling (see above). As with Samoan Starling, the
length of the outer primary varied, ranging from
3–11 mm shorter than the longest primary covert,
but, as in Samoan Starling, we found no relation-
ship between length or shape of p10 and age, sex,
or island of capture. Bill dimensions also showed
little or no variation between sexes, but our data
indicate that wing chord could be used to sex all
birds on each island: R(n55) 99–106 and =(n49)
107–115 mm; birds on Ta’u averaged slightly
smaller than those on Tutuila, within the above
ranges.
DISCUSSION
We present detailed molt strategies and criteria
for determining age and sex in nine species of
American Samoan birds, of seven avian families,
and we assess the degree in which molt and
breeding overlap in each. Preformative molts
varied from absent in one species (Collared
Kingfisher) to complete in one species (many
Purple-capped Fruit-Doves), and there was no
confirmed evidence for prealternate molts in any of
the nine species. We present detailed information
on molt sequences among primaries and second-
aries, and document that a prebasic molt can
commence with feathers retained from the previous
prebasic molt, a staffelmauser-like pattern not
previously documented in passerines. Otherwise,
molt strategies and resulting age-determination
criteria in these birds largely accord with patterns
for other resident non-passerine and passerine
landbirds in tropical areas and elsewhere (Pyle
1997; Higgins 1999; Higgins et al. 2001, 2006;
Wolfe and Pyle 2012; Pyle et al. 2015).
Remigial Molt Sequences
In our nine target species, primaries were
consistently replaced from the innermost (p1) to
the outermost (p10), except in Blue-crowned Lory
where molt proceeded bilaterally from a center at
p5 as is typical in Psittaciformes (Pyle 2013a), and
in some Samoan Shrikebills where molt com-
menced at p2 instead of p1 in five of eight
individuals. Molt commencing from centers other
than p1 is rare among passerines (Pyle 2013a),
although commencement varying from p1 to p4 has
been documented for Rufous Fantail Rhipidura
rufifrons (Junda et al. 2012), another tropical
Pacific flycatcher within or closely related to
Monarchidae.
Among secondaries, sequence proceeded from
the tertials distally and the outermost secondary (s1)
proximally in eight species, a pattern that is very
common to birds (Pyle 1997, 2008). In Blue-crowned
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
65
Lory it proceeded bilaterally from s5, as known in
Psittaciformes (Pyle 2013a), and in Purple-capped
Fruit-Dove, an additional proximal wave pro-
ceeded from s5, a sequence typical of species
showing diastataxy or evolutionary loss of a sec-
ondary between s4 and s5 (Pyle 2008), including
Ptilonopus doves (Bostwick and Brady 2002).
Sequence among the tertials proceeded bilaterally
from a node at the second tertial (t2) in all species
except White-rumped Swiftlet, in which tertial
sequence was not documented. Tertial molt also
proceeded distally from a node at the innermost
tertial (t1) in two species, occurring in 48%of 19
Collared Kingfishers and 11%of 150 Wattled
Honeyeaters. A molt node primarily at t2 and
secondarily at t1 has also been found in both non-
passerine (Pyle 2013a) and passerine (Rohwer
2008; G. David and PP, unpubl. data) birds. It is
currently unknown what proximal mechanisms
account for nodal feathers among tertials or other
remiges, or what adaptive mechanisms could result
in the variation in the commencement node.
We documented terminal molt of secondaries
among s5–s6 in six of our target species. These
feathers are adjacent to the tertials in five passerine
species, but in Collared Kingfisher there are
two extra secondaries (s7–s8) between the tertials
and s5–s6. Among our passerine species, s6 was the
last feather replaced in 100%of 11 Samoan
Shrikebills, 77%of 13 Cardinal Honeyeaters,
80%of 136 Wattled Honeyeaters, 79%of 43
Samoan Starlings, and 86%of seven Polynesian
Starlings. This replacement sequence also coin-
cides with what is found in North American
passerines, many species showing the last feather
replaced as s6 but some individuals of some species
having s6 replaced before s5 and sometimes before
s4 (Rohwer 2008; G. David and PP, unpubl. data).
It is possible that the last feather replaced simply
reflects which of the two waves, distal from
the tertials or proximal from s1, reaches this
section of the secondary tract first, perhaps as
influenced by wing structure and molt-rate factors
in species or individuals. This would indicate that
molt terminus may not be mechanistically fixed or
have an adaptive function within molt strategies
(cf. Rohwer 2008).
Suspended and/or Arrested Molts
Suspended or arrested molts were recorded in
seven of our nine species (all but Collared
Kingfisher and Polynesian Startling), including
34%of 38 Purple-capped Fruit-Doves, 21%of 19
Blue-crowned Lorys, 33%of nine White-rumped
Swiftlets, 7%of 28 Samoan Shrikebills, 14%of
37 Cardinal Honeyeaters, 8%of 519 Wattled
Honeyeaters, and 20%of 102 Samoan Starlings. In
the Purple-capped Fruit-Dove, prebasic molts
appeared to be arrested, with the subsequent
prebasic molt commencing where the previous
molt terminated and again in typical sequence,
resulting in staffelmauser or stepwise molt pat-
terns (Pyle 2006, 2008). Other tropical doves and
pigeons have been recorded undergoing staffel-
mauser (Radley et al. 2011, Pyle et al. 2014),
a molt strategy which appears to result simply from
time constraints on completing a prebasic molt
during the annual cycle (Shugart and Rohwer
1996) but having the ultimate adaptation of
allowing more remiges to be replaced in a single
molt without incurring large, flight-impairing gaps
in the wing (Tucker 1991, Pyle 2005). A greater
prevelance of this strategy in tropical than in
temperate Columbiformes (e.g., Pyle 1997) may
relate to an increased frequency of molt suspension
for breeding, as found in other American Samoan
species. Interestingly, we also captured one
Samoan Starling showing staffelmauser-like re-
placement patterns, the first report of this in
a passerine of which we are aware, although we
concede that this one individual could represent an
anomaly.
In all seven of these species, it appeared molt
could be suspended for breeding or certain phases
of breeding, to be resumed where it terminated
before suspension. Such suspension for breeding
has been noted in other birds, most notably in
diurnal raptors and parrots (Pyle 2005, 2013a). For
tropical species with the potential for year-round or
opportunistic breeding, mechanisms triggering
breeding may occur mid-molt and result in
suspension, something rarely observed in passer-
ines breeding at more temperate latitudes. Our data
from Wattled Honeyeaters suggest that molt
suspension for breeding happens more frequently
in females than in males, perhaps as related to the
onset of sex-specific breeding hormones, or
because of greater breeding constraints on females
than males (cf. Freed and Cann 2013). Assessments
of molt suspension have not always been explored
during studies of molt-breeding overlap in tropical
species (e.g., Johnson et al. 2012), and we suggest
that suspensions be recorded and incorporated in
analyses of molt and breeding regimes (cf. Freed
and Cann 2012). It is possible that molt-breeding
overlap may increase when populations are
66
THE WILSON JOURNAL OF ORNITHOLOGY NVol. 128, No. 1, March 2016
stressed, perhaps especially in females (Freed and
Cann 2012, 2013), and this should be considered in
future studies of this interesting dynamic within the
full cycle of birds.
Arrested molts are technically defined as those
which are not completed before the following
prebasic molt, whereas suspended molts occur
within a single molt cycle. In both staffelmauser
and molt suspensions, a memory variable is
involved in which the sequence commences where
it previously terminated. Although nothing is
currently known about how such a memory vari-
able operates in remigial molt sequences of birds
(Bridge 2011), it may involve a neurological as
opposed to a hormonal mechanism (Pyle 2013a).
Of interest in this regard are five Wattled
Honeyeaters and two Samoan Starlings in our
study that appeared to arrest molt before s5 and/or
s6 were replaced. These birds then initiated the
next molt with the arrested feathers along with
those feathers (inner primaries and tertials) that
typically commence a molt sequence. Along with
the Samoan Starling exhibiting a stafflemauser-
like pattern, this suggests that staffelmauser and
suspension for molt in passerines may share
a common ancestral mechanism involving both
stable phylogenetic replacement sequences (Pyle
2013a) and a memory variable acting to bridge
suspension gaps. Staffelmauser and molt suspen-
sions have been documented in a wide variety of
bird families as dependent on time constraints for
molting (Pyle 2006, 2008; this study), further
suggesting that these are fixed molting mech-
anisms. Our data support the premise that similar
underlying molting strategies can be expected
within landbird families throughout the world, as
shaped by local environmental factors and time
constraints, and that resulting age criteria such as
feather shapes and molt limits also show similar
global patterns.
Molt-Breeding Overlap
We assessed molt-breeding overlap in individual
birds using brood patch and cloacal protuberance to
indicate active reproductive state. Overlapping
breeding and molting seasons at the population
level have been used in previous studies to assess
molt-breeding overlap, but this does not always
imply simultaneous breeding and molting in
individuals, especially in tropical species where
both molting and breeding seasons are much more
protracted than typically required for an individual
bird to either breed or molt (Johnson et al. 2012).
Assessment of molt-breeding overlap using active
reproductive condition in live individuals is
preferable to previously used methodologies
(Freed and Cann 2012, Johnson et al. 2012);
however, scoring of brood patches and cloacal
protuberances in live birds can be inconsistent
between observers, often involving the assumption
of an active condition in non-breeding birds (PP,
pers. obs.). This may lead to falsely high rates of
reported molt-breeding overlap, at the individual
level, using this method.
Despite broad overlap of breeding and molting
seasons at the population level, we observed little
evidence of molt-breeding overlap in our sample of
Samoan landbird species. Only in Wattled Honey-
eater did we encounter birds showing evidence of
simultaneous breeding and molting, representing
11.4%of actively breeding birds (see Johnson et al.
2012) and 6.4%of those showing evidence of
active breeding or active molting. All individuals
recorded simultaneously breeding and molting
were just commencing or just completing molt,
and we suspect that, along with the potential for
misassignment of reproductive condition scores,
that there are strong physiological mechanisms
resulting in the separation of molting and breeding
in Wattled Honeyeater and our other study species.
The annual complete or near-complete replace-
ment of feathers in adult birds may accompany
a restoration process associated with whole-body
protein synthesis and suppression of the immune
system as regulated in part by thyroidal activity
(Murphy 1996, Kuenzel 2003). We consider it
unlikely that individuals of many species would
also breed while undergoing such a process.
Furthermore, molt may show seasonal predomi-
nance over breeding, as suggested by the well-
defined molting season in our Wattled Honeyeaters
and other species despite apparent year-round
or bi-modal breeding within the population. Our
results further indicate that molt can be suspended
and resumed, enabling opportunistic breeding
when environmental conditions shift to facilitate
successful reproduction.
ACKNOWLEDGMENTS
We are indebted to the U.S. Fish and Wildlife Service for
providing funding through a Wildlife Restoration Grant to
the American Samoa and Department of Marine and Wildlife
Resources (DWMR) in American Samoa, and to DWMR for
facilitating our research. The following individuals in Samoa
helped in various ways: Ray Tulafono, Ruth Matagi-Tofiga,
Selaina Vaitautolu-Tuimavave, Shelly Kremer, Lainie
Zarones, Ruth Utzurrum, Siaifoi Faaumu, Matthew Toilolo,
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
67
Adam Miles, Ailao Tualaulelei, Mark MacDonald, Sean
Eagan, James Bacon, Tavita Togia, Kiolona Atanoa, Loia
Tagoni, and Panini Seafa. We are extremely grateful to the
National Park of American Samoa and to the following
Samoan landowners for granting us permission to establish
TMAPS stations on their lands: Alo Pete Steffany, Utu Ron,
Wesley Tulefano, Easter Tom Bruce, the Asi family,
Fuimaono Asuemu, the Lauti family, the Gurr family, the
Tula family, Sau and Usu Nua, the Saunoa family, and the
Fala’a family. We thank field biologists who collected data
for the TMAPS Program: Alfredo Arcilla Jr., Rudy Badia,
Adrienne Doyle, Siaifoi Faaumu, Simon Fitz-William,
Emily Jeffreys, Samuel Jones, Daniel Lipp, Vicki Morgan,
Colleen Nell, Jessie Reese, Zachary Robinson. Ropi
Seumanutafa, Josh Tigilau, and Salefu Tuvalu, and PP is
indebted to the managers of the following specimen
collections for assistance: Museum of Vertebrate Zoology
(Carla Cicero), California Academy of Sciences (Jack
Dumbacher and Maureen Flannery), Western Foundation
of Vertebrate Zoology (Linnea Hall and Adam Searcy), Field
Museum of Natural History (John Bates), United States
Museum of Natural History (Storrs Olson and James Dean),
Yale Peabody Museum (Kristof Zyskowski), Museum of
Comparative Zoology (Jeremiah Trimble), and the Louisiana
State University (Donna Ditmann and Steve Cardiff); a travel
grant from the University of California, Davis (UCD11-
02122) facilitated PP’s visit to eastern North American
museums for this and other specimen-based research. The
manuscript was improved following critical reviews from
Jared Wolfe, Gabriel David, and an anonymous reviewer.
We thank Rodney Siegel, Erin Rowan, Ron Taylor, and
Lauren Helton of the Institute for Bird Populations (IBP) for
logistical and technical support. This is IBP Contribution
Number 494.
LITERATURE CITED
AMADON, D. 1942. Birds collected during the Whitney South
Sea Expedition. 50. Notes on some non-passerine
genera, 2. American Museum Novitates 1176:1–21.
AMADON, D. 1943a. Birds collected during the Whitney
South Sea Expedition. 52: notes on some non-passerine
genera, 3. American Museum Novitates 1237:1–22.
AMADON, D. 1943b. The genera of starlings and their
relationships. American Museum Novitates 1247:1–16.
BANKS, R. C. 1984. Bird specimens from American Samoa.
Pacific Science 38:150–169.
BOSTWICK,K.S.AND M. J. BRADY. 2002. Phylogenetic
analysis of wing feather taxis in birds: macroe
volutionary patterns of genetic drift? Auk 119:943–
954.
BRIDGE, E. S. 2011. Mind the gaps: what’s missing in our
understanding of feather molt. Condor 113:1–4.
DESANTE, D. F., K. M. BURTON,J.F.SARACCO,AND B. L.
WALKER. 1995. Productivity indices and survival rate
estimates from MAPS, a continent-wide programme of
constant-effort mist-netting in North America. Journal
of Applied Statistics 22:935–948.
DESANTE, D. F., K. M. BURTON,P.VELEZ,AND D.
FROEHLICH. 2012. MAPS manual: 2012 protocol.
Instructions for the establishment and operation of
constant-effort bird-banding stations as part of the
Monitoring Avian Productivity and Survivorship
(MAPS) program. The Institute for Bird Populations,
Point Reyes Station, California, USA.
DESANTE, D. F., T. S. SILLETT,R.B.SIEGEL,J.F.
SARACCO,C.A.ROMO D E VIVAR ALVAREZ,S.
MORALES,A.CEREZO,D.R.KASCHUBE,M.GROSSE-
LET,AND B. MILA
´. 2005. MoSI (Monitoreo de
Sobrevivencia Invernal): assessing habitat-specific
overwintering survival of Neotropical migratory
landbirds. Pages 926–936 in Bird conservation im-
plementation and integration in the Americas: pro-
ceedings of the third international Partners in Flight
conference. Volume 2 (C. J. Ralph and T. D. Rich,
Editors). USDA, Forest Service, General Technical
Report PSW-GTR-191. Pacific Northwest Research
Station, Portland, Oregon, USA.
FREED,L.A.AND R. L. CANN. 2009. Negative effects of
an introduced bird species on growth and survival in
a native bird community. Current Biology 19:
1736–1740.
FREED,L.A.AND R. L. CANN. 2012. Changes in timing,
duration, and symmetry of molt of Hawaiian forest
birds. PLoS One 7:e29834. doi:10.1371/journal.
pone.0029834
FREED,L.A.AND R. L. CANN. 2013. Females lead
population collapse of the endangered Hawaii Creeper.
PLoS One 8:e67914. doi:10.1371/journal.
pone.0067914
HIGGINS,P.J.(EDITOR). 1999. Handbook of Australian,
New Zealand and Antarctic birds. Volume 4: parrots to
Dollarbird. Oxford University Press, Melbourne,
Australia.
HIGGINS, P. J., J. M. PETER,AND S. J. COWLING (EDITORS).
2006. Handbook of Australian, New Zealand and
Antarctic birds. Volume 7: Boatbill to starlings.
Oxford University Press, Melbourne, Australia.
HIGGINS, P. J., J. M. PETER,AND W. K. STEELE (EDITORS).
2001. Handbook of Australian, New Zealand and
Antarctic birds. Volume 5: tyrant-flycatchers to chats.
Oxford University Press, Melbourne, Australia.
HOWELL, S. N. G., C. CORBEN,P.PYLE,AND D. I. ROGERS.
2003. The first basic problem: a review of molt and
plumage homologies. Condor 105:635–653.
HUMPHREY,P.S.AND K. C. PARKES. 1959. An approach to
the study of molts and plumages. Auk 76:1–31.
JOHNSON, E. I., P. C. STOUFFER,AND R. O. BIERREGAARD
JR. 2012. The phenology of molting, breeding and
their overlap in central Amazonian birds. Journal of
Avian Biology 43:141–154.
JOHNSON, E. I., J. D. WOLFE,T.B.RYDER,AND P. PYLE.
2011. Modifications to a molt-based ageing system
proposed by Wolfe et al. (2008). Journal of Field
Ornithology 82:422–424.
JUNDA, J. H., A. L. CRARY,AND P. PYLE. 2012. Two modes
of primary replacement during prebasic molt of
Rufous Fantails Rhipidura rufifrons. Wilson Journal
of Ornithology 124:680–685.
KUENZEL, W. J. 2003. Neurobiology of molt in avian
species. Poultry Science 82:981–991.
68
THE WILSON JOURNAL OF ORNITHOLOGY NVol. 128, No. 1, March 2016
MAYR, E. 1933. Birds collected during the Whitney South
Sea Expedition. 24: notes on Polynesian flycatchers
and a revision of the genus Clytorhynchus Elliot.
American Museum Novitates 628:1–21.
MAYR, E. 1941. Birds collected during the Whitney South
Sea Expedition. 47: notes on the genera Halcyon,
Turdus and Eurostopodus. American Museum Novi-
tates 1152:1–7.
MAYR, E. 1942. Birds collected during the Whitney South
Sea Expedition. 48: notes on the Polynesian species of
Aplonis. American Museum Novitates 1166:1–6.
MURPHY, M. E. 1996. Energetics and nutrition of molt.
Pages 158–198 in Avian energetics and nutritional
ecology (C. Carey, Editor). Chapman and Hall, New
York, USA.
PRATT, H. D. 2010. Revisiting species and subspecies of
island birds for a better assessment of biodiversity.
Ornithological Monographs 67:79–89.
PYLE, P. 1997. Identification guide to North American
birds. Part 1. Columbidae to Ploceidae. Slate Creek
Press, Bolinas, California, USA.
PYLE, P. 2005. Remigial molt patterns in North American
Falconiformes as related to age, sex, breeding status,
and life-history strategies. Condor 107:823–834.
PYLE, P. 2006. Staffelmauser and other adaptive strategies
for wing molt in larger birds. Western Birds 37:
179–185.
PYLE, P. 2008. Identification guide to North American
birds. Part 2. Anatidae to Alcidae. Slate Creek Press,
Point Reyes Station, California, USA.
PYLE, P. 2013a. Evolutionary implications of synapomorphic
wing-molt sequences among falcons (Falconiformes)
and parrots (Psittaciformes). Condor 115:593–602.
PYLE, P. 2013b. Updated manual for ageing and sexing
landbirds of American Samoa. The Institute for Bird
Populations, Point Reyes Station, California, USA.
PYLE, P., A. ENGILIS JR., AND D. A. KELT. 2015. Manual for
ageing and sexing landbirds of Bosque Fray Jorge
National Park and north-central Chile, with notes on
range and breeding seasonality. Special Publication of
the Museum of Natural Science, Louisiana State
University, Baton Rouge, USA.
PYLE, P., A. MCANDREWS,P.VELE
´Z,R.L.WILKERSON,R.
B. SIEGEL,AND D. F. DESANTE. 2004. Molt patterns
and age and sex determination of selected southeastern
Cuban landbirds. Journal of Field Ornithology 75:
136–145.
PYLE, P., N. S. ARCILLA,K.TRANQUILLO,K.KAYANO,A.
DOYLE,S.JONES,D.KASCHUBE,R.TAYLOR,
AND E. ROWAN. 2014. The Tropical Monitoring Avian
Productivity and Survivorship (TMAPS) program in
American Samoa: 2014 report. The Institute for
Bird Populations, Point Reyes Station, California,
USA.
RADLEY, P., A. L. CRARY,J.BRADLEY,C.CARTER,AND P.
PYLE. 2011. Molt patterns, biometrics, and age and
gender classification of landbirds on Saipan, Northern
Mariana Islands. Wilson Journal of Ornithology
123:588–594.
ROHWER, S. 2008. A primer on summarizing molt data for
flight feathers. Condor 110:799–806.
RYDER,T.B.AND J. D. WOLFE. 2009. The current state of
knowledge on molt and plumage sequences in selected
Neotropical bird families: a review. Ornitologı
´a
Neotropical 20:1–18.
SARACCO, J. F., J. A. ROYLE,D.F.DESANTE,AND B.
GARDNER. 2012. Spatial modeling of survival and
residency and application to the Monitoring Avian
Productivity and Survivorship program. Journal of
Ornithology 152 (Suppl. 2):S469–S476.
SHUGART,G.W.AND S. ROHWER. 1996. Serial descendant
primary molt or Staffelmauser in Black-crowned
Night-Herons. Condor 98:222–233.
STRESEMANN,E.AND V. STRESEMANN. 1966. Die Mauser
der Vo¨gel. Journal fu¨ r Ornithologie 107(Suppl.):
1–448.
TUCKER, V. A. 1991. The effect of molting on the gliding
performance of a Harris’ Hawk (Parabuteo unicinc-
tus). Auk 108:108–113.
WOLFE,J.D.AND P. PYLE. 2012. Progress in our
understanding of molt patterns in Central American
and Caribbean landbirds. Ornitologı
´a Neotropical
23:169–175.
WOLFE, J. D., P. PYLE,AND C. J. RALPH. 2009. Breeding
seasons, molt patterns, and gender and age criteria for
selected northeastern Costa Rican resident landbirds.
Wilson Journal of Ornithology 121:556–567.
WOLFE, J. D., T. B. RYDER,AND P. PYLE. 2010. Using molt
cycles to categorize the age of tropical birds: an
integrative new system. Journal of Field Ornithology
81:186–194.
Pyle et al. NMOLT IN SAMOAN LANDBIRDS
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