Radley el al. • LANDBIRD MOLT ON SAIPAN 
589 
based on specimen examination and initial 
banding data presented by Pyle et al. (2008). 
METHODS 
Saipan (15° 12' N, 145'' 45' E), a tropical Pacific 
island (122.9 knr) in the Mariana Archipelago, is 
characterized by a rugged north-south limestone 
ridge which reaches an elevation of 436 m with low 
lying plateaus extending from its base. The island's 
major habitat cover types are native limestone 
evergreen forest, tangan-tangan (Leucaena leuco- 
cephala ) scrub, mixed evergreen forests, tropical 
savannahs, and swordgrass {Macanthus JlorUlulus) 
thickets. Saipan’s climate is marine tropical, hot 
and humid, and characterized by relatively high and 
uniform yearly temperatures. A wet season gener¬ 
ally occurs from July through October, the last 
2 months have increased incidence of typhoons. 
CNMI-DFW and IBP established six banding 
stations on Saipan in 2008 to monitor productivity 
and survivorship of the island's landbird popula¬ 
tions. Stations were specifically placed to facilitate 
sampling birds in all representative cover types or 
some combination thereof. Each station comprised 
8-1012-mm mist nets operated one morning during 
each of nine 10-day periods from 13 April to 17 
July 2008 and 11 April to 15 July 2009. We 
captured 1,778 individuals of nine species of native 
resident landbirds 2,419 times over the two seasons. 
Standard measurements and morphometric data 
were collected for all birds captured; age and 
gender were assigned to each following criteria in 
Pyle (1997, 2008; and developed in this paper). We 
also operated the stations from 20 February to 15 
October 2010 and collected additional data on molt, 
biometrics, and plumage patterns. Pyle reviewed 
267 relevant museum specimens (range = 8-53/ 
species) prior to the 2008 TMAPS season to 
establish preliminary criteria for age and gender 
classification (Pyle et al. 2008). Most specimens 
had been collected on Saipan but some were 
collected elsewhere in the Mariana Islands or 
Micronesia, provided they represented the same 
species and subs-pecies occurring on Saipan. The 
gender of most specimens examined had been 
previously established by gonadal examination; 
these specimens formed the basis for gender- 
specific measurement and plumage differences 
reported. Criteria for gender classification were 
further assessed based on presence or absence of 
reproductive characters (brood patch and cloacal 
protuberance) in birds captured during presumed 
periods of breeding for each species on Saipan. 
Molt and plumage terminology is based upon 
Howell et al.’s (2003) revision of Humphrey and 
Parkes (1959) nomenclature, while feather-tract 
and age terminologies, flight-feather numbering, 
and other abbreviations follow Pyle (1997, 2008). 
Primaries and primary coverts are numbered from 
the innermost (primary 1) to outermost (primary 9 
or 10). secondaries from the outermost (secondary 
1) to innermost tertials (secondary 9, 10, or 11), 
and rectrices from the central pair (rectrix 1) to 
the outermost pair (rectrix 5 or 6). Abbreviations 
used include: PF = preformative (formerly 
considered 'first prcbasic') molt, DPB = defini¬ 
tive prebasic moll, BP = brood patch, and CP = 
cloacal protuberance. 
Accurate age classification may be complicated 
by an apparent lack of distinct, calendar-year 
breeding seasonality of birds on Saipan, a trait 
that can be exhibited by species resident in 
tropical latitudes (Wolfe et al. 2009a, b). Thus, 
age diagnostics and classifications follow the 
molt-cycle-based system devised by Wolf et al. 
(2010) for tropical species and include: FCJ. a 
bird in its first molt cycle and entirely in juvenal 
plumage; FCF, a bird in its first molt cycle and in 
formative plumage (or having begun the prefor¬ 
mative molt); SCB, a bird in its second molt cycle 
(or having begun the second prebasic molt) and in 
basic plumage; TCB. a bird in its third molt cycle 
(or having begun the third prebasic molt) and in 
basic plumage; and DCB, a bird in its definitive 
molt cycle (or having begun the definitive 
prebasic molt) and in basic plumage. 
We report our findings of molt and classifica¬ 
tion of age and gender for nine of 14 native 
landbirds resident to Saipan, four of which are 
endemic to the Mariana Archipelago. Sample 
sizes for each species indicate the number of 
specimens examined, the number of individuals 
captured and processed, and the total number of 
individual captures. We report feather-replace¬ 
ment sequence as ‘typical’ if it proceeded distally 
from primaries I to 10. and proximally from 
secondaries after the tertials had been replaced (cf 
Pyle 1997); the two doves showed an extra center 
at secondary 5 as is typical in diastitaxic birds 
(Pyle 2008). We did not detect evidence of 
prealtemate molts in any species. 
RESULTS 
White-throated Ground Dove (Gallicolumba 
xanthonura ; n = 21 specimens, 38 individuals, 
43 captures). Both PF and DPB are incomplete to 
