Duration Of Moult Research Articles

Life Cycles of Seven Ixodid Tick Species (Acari: Ixodidae) Under Standardized Laboratory Conditions

Studies of transmission, maintenance, infectivity, virulence, and pathogenicity of tick-borne agents require the use of large numbers of live laboratory-raised ticks. Colonies of Ixodes scapularis Say, Ixodes pacificus Cooley & Kohls, Amblyomma americanum (L.), Dermacentor occidentalis Marx, Dermacentor variabilis (Say), Hemaphysalis leporispalustris (Packard), and Rhipicephalus sanguineus (Latrielle) have been maintained in our laboratory at the Centers for Disease Control and Prevention for five to 18 continuous generations. New Zealand White rabbits (Oryctolagus cuniculus) are used as hosts for all tick species and developmental stages. Between feedings, ticks are stored in environmental incubators at 22-24 degrees C and 90% RH with a day/night photoperiod of 16:8 (L:D) h. The duration of feeding, molting, preoviposition, and periods of postmolting development were recorded. Here, we describe the life cycles of these common North American tick species under standardized laboratory conditions. At 22-24 degrees C, the minimal time needed for each species to complete one life cycle was as follows: I. scapularis, 204-219 d; I. pacificus, 214-229 d; R. sanguineus, 162-177 d; H. leporispalustris, 209-224 d; D. variabilis, 176-191 d; D. occidentalis, 180-195 d; and A. americanum, 192-211 d.

Life Cycles of Seven Ixodid Tick Species (Acari: Ixodidae) Under Standardized Laboratory Conditions

Studies of transmission, maintenance, infectivity, virulence, and pathogenicity of tick-borne agents require the use of large numbers of live laboratory-raised ticks. Colonies of Ixodes scapularis Say, Ixodes pacificus Cooley & Kohls, Amblyomma americanum (L.), Dermacentor occidentalis Marx, Dermacentor variabilis (Say), Hemaphysalis leporispalustris (Packard), and Rhipicephalus sanguineus (Latrielle) have been maintained in our laboratory at the Centers for Disease Control and Prevention for five to 18 continuous generations. New Zealand White rabbits (Oryctolagus cuniculus) are used as hosts for all tick species and developmental stages. Between feedings, ticks are stored in environmental incubators at 22–24°C and 90% RH with a day/night photoperiod of 16:8 (L:D) h. The duration of feeding, molting, preoviposition, and periods of postmolting development were recorded. Here, we describe the life cycles of these common North American tick species under standardized laboratory conditions. At 22–24°C, the minimal time needed for each species to complete one life cycle was as follows: I. scapularis, 204–219 d; I. pacificus, 214–229 d; R. sanguineus, 162–177 d; H. leporispalustris, 209–224 d; D. variabilis, 176–191 d; D. occidentalis, 180–195 d; and A. americanum, 192–211 d.

Moult of Guinea savanna passerines in West Africa

Moult timing and duration was estimated in 17 passerine bird species in the guinea savanna zone of Nigeria. In 15 species, moult duration was much longer than in the equivalent north temperate resident passerines. Sixteen species were found to moult seasonally, with most granivorous species moulting in the dry season. General seasonal patterns of either insectivores or nectarivores were not apparent. These results are discussed in the context of other important aspects of the annual cycle and the life history styles of tropical birds.

Effects of changes in salinity and temperature on survival and development of larvae and juveniles of the crucifix crab Charybdis feriatus (Crustacea:Decapoda:Portunidae)

An experiment was carried out to determine the effects of changes in temperature and salinity on the survival and development of the larvae (zoea, megalopa) and crab instar 1 (C1) juveniles of the crucifix crab, Charybdis feriatus. Larvae and juveniles in each stage of development were reared at various salinity and temperature combinations: four salinities of 15, 25, 35 and 45‰ for each of the 5 zoea stages, five salinities of 5, 15, 25, 35, 45‰ for the megalopa and six salinities of 0, 5, 15, 25, 35, 45‰ for the C1 juveniles, at temperatures of 20, 26 and 32 °C. Results showed that both salinity and temperature significantly affected survival of larvae and juveniles and there was a significant interaction between salinity and temperature. There was generally high survival of zoea and megalopa at 25, 35‰ in 26, 32 °C and of C1 at 25‰ in 20, 26, 32 °C. Salinity and temperature also affected onset of development and duration of molt. There was rapid and synchronous development at 25 and 35‰ but delayed and extended at 45‰. With decreasing temperature, there was a delay in the start of development and duration of molt was prolonged. Larvae and juveniles did not survive in 15‰ even with 6 h of acclimation while larvae survived at 45‰ during abrupt and gradual transfer. The optimum salinity–temperature combination recommended for the larval and nursery rearing of C. feriatus is 25–35‰ at 26–32 °C.

Breeding seasonality and primary moult parameters of Euplectes species in South Africa

The grassland biome in South Africa has a summer rainfall and Southern Red Bishops Euplectes orix, Fan-tailed Widows E. axillaris, White-winged Widow E. albonotatus, Red-collared Widow E. ardens and Long-tailed Widow E. progne breed from October or November to March. Primary moult starts in late March or early April. The widows with long tails (Long-tailed and Red-collared Widows) have moult durations of two months, while the widows with shorter tails (White-winged and Fan-tailed Widows) had moult durations of 1.5–1.7 months. Moult ends in late May or early June. Long-tailed Widows have rounder wings than other weaver species, possibly because their larger size affects flight aerodynamics. In the winter rainfall region, Southern Red Bishops and Yellow Bishops E. capensis start breeding after the winter rains, from August–November, and moult starts in early December. Primary moult duration in Yellow Bishops is relatively long, at 3.4 months. Yellow Bishops grow individual primary feathers at an average rate of 21.3 days per feather, while the other species moult primaries more quickly: White-winged Widow 8.1 days, Fan-tailed Widow 11.3 days, and Red-collared Widow 14.4 days. The number of primaries growing simultaneously is similar in the different species. The longer duration of primary moult of the Yellow Bishop may be related to food.

Prebasic Molt and Molt-Related Movements in Ash-Throated Flycatchers

AbstractWe describe the timing and location of the prebasic molt in the Ash-throated Flycatcher (Myiarchus cinerascens), a hawking insectivore with resident populations in Mexico and migrant populations that breed in the western United States. The timing of fall molt with respect to migration is of particular interest for Ash-throated Flycatchers from the United States because they breed in arid lowland habitats that are probably unproductive in late summer, and because time constraints on molt might force northern populations to leave their breeding grounds before molting. Adults and juveniles depart their breeding grounds to arrive and molt in the region of the Mexican monsoon shortly after the monsoon rains begin. Diminishing food on the breeding grounds and increasing food in the monsoon region seem more important than time constraints for explaining molt-related movements by northern populations, because more southerly breeding birds east and west of the monsoon region also move to the monsoon region to molt. We found age class differences in the timing and duration of molt. In adults the primary molt starts approximately 14 July and requires 76 days to complete, whereas in juveniles, primary molt starts approximately 1 August (18 days after adults) but requires only 50 days to complete. We found no evidence that juveniles molt more primaries simultaneously than adults, so we conclude that the daily growth rate of individual feathers must be higher in juveniles than adults.

Moult in captive partially migratory and sedentary Australian silvereyes (Zosterops lateralis) (Zosteropidae)

In this study, we describe and compare the duration and timing of post-breeding moult of primary and secondary wing feathers, tail feathers, wing coverts and body feathers in captive partially migratory and non-migratory Australian silvereyes (Zosterops lateralis). This study allowed us to follow individual birds through the course of their moult and record the progression of moult in two populations. Both groups of birds underwent a conventional (or basic) post-breeding moult. While all birds followed a similar pattern of feather replacement, differences were found in the timing and duration of moult between migratory and non-migratory birds. The migratory birds generally started their moult earlier in the year and completed it before the non-migratory birds. The migratory birds revealed an overall uniformity in the timing and duration of their moult, while the non-migratory birds showed a greater degree of variability between individuals.

Molecular mechanisms regulating molting in a crustacean

Crustacean growth and development is characterized by periodic shedding (ecdysis) and replacement of the rigid exoskeleton. Secretions of the X-organ sinus gland complex control the cellular events that lead to growth and molting. Western blot and ELISA results showed a progressive increase in growth arrest-specific protein (Gas7) from early postmolt stage to a maximum at late postmolt stage. Phosphorylation of ERK2, a downstream signaling protein, was also identified in the subsequent stages. ERK2 phosphorylation resulted in the expression of molt-inhibiting hormone (MIH). Specific ERK inhibitors (PD98059 and UO126) exhibited the ability to reduce the molting duration of Fenneropenaeus indicus from 12-14 days to 7-8 days, suggesting that the ERK1/2 signaling pathway is responsible for the expression of MIH, which controls the molt cycle. We have identified the stage-specific expression of Gas7 (approximately 48 kDa) in the X-organ sinus gland complex of eyestalk which is involved in the downstream signaling of the ERK1/2 pathway regulating the expression of MIH during the molt cycle of the white shrimp, F. indicus. These are the first data showing an association between the Gas7 signal-transduction process and regulation of the molt cycle and provides an alternative molecular intervention mechanism to the traditional eyestalk ablation in crustaceans.

Large-Scale Patterns of Molt Activation in the Flight Feathers of two Albatross Species

Abstract Laysan Albatross (Phoebastria immutabilis) and the closely-related Black-footed Albatross (P. nigripes) replace 20%–90% of their 35–41 wing flight feathers every year. Large-scale molt patterns (patterns between rather than within molt series) account for 77% of the variation in the number of flight feathers replaced. We identified four molt series: series A—the five outer primaries; series B—the five inner primaries plus four outer secondaries; series C—the middle secondaries; and series D—the inner secondaries. A fifth molt series may lie between series C and D. Each year, series A and D initiate molt, but series B and C may or may not initiate molt. The result is four “annual molt patterns”: ABCD, ABD, ACD, and AD. Temporally overlapping waves of molt never occur within series A or B, but about one third of the time they occur within series C and D. Multiple, spatially defined waves of molt (replaced feathers separated by unreplaced feathers) never occur within series A, but occur about two thirds of the time within series B, C, and D. The inner primaries and outer secondaries constitute a single molt series, probably to equilibrate between series total feather length, and thus, total molt duration. Studies of foraging range and reproduction in albatrosses would benefit from the development of species-specific indices of molt duration and extent that are biologically as well as statistically defensible. The number of outer primary feathers replaced and the number of molt series that activate molt are two such indices for Laysan and Black-footed Albatrosses.

The timing, duration and pattern of moult and its relationship to breeding in a population of the European Greenfinch Carduelis chloris

Moult was studied in 1 year among Greenfinches trapped in a garden in east‐central England. Over the period June–December 2003, 333 captures of 179 individual adults provided information on breeding condition, moult, body weight, sex and age (yearling or older adult, equivalent to birds in their second or later calendar years, respectively). About 95% of all birds (sex and age groups combined) started primary feather moult from 2 July to 14 August, and finished from 10 October to 22 November. The mean date of moult onset in the population as a whole was 24 July. On average, males began 8 days before females, and yearlings began 6 days before older birds. The mean duration of moult was 100 days, whether the figure was calculated for the population as a whole or just for the 36 individual birds that were caught more than once during moult. However, moult rate was slightly slower, and moult duration slightly longer, in yearlings than in older adults of both sexes. No evidence was found for any systematic relationship between moult onset date and rate (duration). Breeding and moult overlapped by up to 5 weeks or more in individual birds, and some birds probably started to moult as early as the incubation stage of their last clutch of the season. The cloacal protuberance (taken as indicative of breeding condition) had regressed in all males by the time the fifth primary was shed, and the brood patch had regressed and re‐feathered in all females by the time the fourth primary was shed. The bulk of feather replacement in the secondary, tail and body tracts occurred in the second half of primary moult, and after cloacal protuberances and brood patches were completely regressed. In all birds examined near the end of primary moult the secondaries were still growing, and would have continued growth for up to another 19 days or more, extending the end of the moulting season into December. Body mass during moult was affected significantly by sex and age, as well as by time of day, amount of food in gullet, reproductive condition and date. No firm evidence emerged that body mass was affected by moult stage, after allowing for effects of date and other variables (although there was a non‐significant negative relationship between moult stage and body mass in males). In the population as a whole, the breeding season (from first egg‐laying to independence of last young) was spread over 21 weeks and moult over 24 weeks. With an overlap between the two events at the population level of up to 9 weeks, the two processes together took up to 36 weeks, some 69% of the year.

Chestnut Weaver Ploceus rubiginosus biometrics and primary moult in Namibia

Seasonal variation in body mass and wing length, and the onset and duration of primary moult, were investigated for Chestnut Weavers from northern Namibia. Body mass of adult males was 31.2g (SD 2.6), and adult females weighed 27.4g (SD 1.9). Body mass declined from March to April, and started increasing after August (i.e. near the end of moult) in males and females. Wing length in adult males with new primaries (Oct–Feb) was 80.7mm (SD 2.7) and for adult females (Oct–Feb) 76.8mm (SD 2.6). For both sexes wing length declined during and after the breeding season, due to extensive feather wear. Adult males started primary moult significantly earlier than females (9 April vs 30 April) and moult lasted longer (206 days vs 189 days). The peak summer rainfall and the start of primary moult was earliest in 2000 and latest in 2004 for males and females. Individual primary feathers took 11–18 days to grow.

Flexible Seasonal Timing and Migratory Behavior: Results from Stonechat Breeding Programs

Rigid schedules of long-distance migrants could be among candidate traits for adaptive migratory syndromes. This prediction was tested on stonechats, passerines that differ widely in migratory behavior and seasonal schedules. Stonechats in Europe are short-distance migrants and multiclutched, whereas African residents and Siberian long-distance migrants usually raise single broods. In captivity, all subspecies displayed endogenous cycles of reproductive development and molt. The subspecies differed in time afforded to life cycle stages. Under conducive aviary conditions, African stonechats were multibrooded, whereas Siberian stonechats did not add clutches. This difference in flexibility was exclusively related to the length of breeding windows. Stonechats also differed in premigratory preparations. Postjuvenile molt started early in Siberian stonechats, but in European and African stonechats, depended strongly on hatching date. In contrast, all subspecies shortened molt duration at the same rate when hatched from late broods. Plasticity of Zugunruhe timing was identical in Siberian and European subspecies and nearly compensated for hatching late. The stonechat data suggest a refined understanding of temporal plasticity in long-distance migrants. Overall, plasticity was not reduced, but was differently organized. Apparently rigid migrant schedules were related to short breeding cycles and inflexible molt onset. Short windows for breeding and juvenile development could provide safety measures for timely departure. Once molt was initiated, temporal plasticity of long-distance migrants matched that of less migratory conspecifics. In addition to adjusting endogenous programs, stonechats differed in implementing them in the field. Modifying the conditions under which programs are expressed may be an efficient way to enhance seasonal plasticity.

Biometrics, ageing, sexing and moult of the Blue Chaffinch Fringilla teydea teydea on Tenerife (Canary Islands)

The Blue Chaffinch Fringilla teydea is one of a few Palearctic species for which biometric data are lacking from the field; we address this issue here. Blue Chaffinches were caught by mist net, at ten sites on Tenerife (Canary Islands), and measured. Data on biometrics and moult using standard methods are presented, and observations on mass variation in relation to time of day and body size are reported for the first time. Wing length, bill length, bill depth & tail were greater in adults and first year birds than juveniles whilst tarsus and mass were the same. The species shows a clear sexual dimorphism in size except for bill length. The duration of primary moult was estimated to be 66 days for adults. For first year birds (in their second‐calendar year), the mean starting date of primary moult was 25 days earlier than adults and was completed after 109 days.

Sociable Weaver biometrics and primary moult

The biometric and primary moult data housed at the South African Bird Ringing Unit (SAFRING) were analysed for the Sociable Weaver Philetairus socius. The average body mass and wing length was 27.9g (SD = 2.2) and 74.1mm (SD = 2.5), respectively. Variation in these parameters is not clearly correlated with region, season or climate, other than a negative correlation of body mass with average annual water deficiency. Body mass of Sociable Weavers near Kimberley showed a longterm decrease of 2.9g, probably due to stabilising selection on mass. Primary moult duration varied from 152 days to 169 days and started between 26 January and 31 December in two populations (socius and South African eremnus respectively). Individual primaries moulted mainly one at a time, each taking 20–28 days to grow fully. Prolonged moult duration in this species is probably an adaptation to reduce energy expenditure, and to grow more durable feathers due to abrasion in entering the nest. The lack of clear patterns of geographical variation in biometrics indicates that the contiguous populations of Sociable Weaver should belong to the nominate species. The biometric and primary moult data housed at the South African Bird Ringing Unit (SAFRING) were analysed for the Sociable Weaver Philetairus socius. The average body mass and wing length was 27.9g (SD = 2.2) and 74.1mm (SD = 2.5), respectively. Variation in these parameters is not clearly correlated with region, season or climate, other than a negative correlation of body mass with average annual water deficiency. Body mass of Sociable Weavers near Kimberley showed a longterm decrease of 2.9g, probably due to stabilising selection on mass. Primary moult duration varied from 152 days to 169 days and started between 26 January and 31 December in two populations (socius and South African eremnus respectively). Individual primaries moulted mainly one at a time, each taking 20–28 days to grow fully. Prolonged moult duration in this species is probably an adaptation to reduce energy expenditure, and to grow more durable feathers due to abrasion in entering the nest. The lack of clear patterns of geographical variation in biometrics indicates that the contiguous populations of Sociable Weaver should belong to the nominate species.

Timing of moult and breeding in the Cape White-eye, Zosterops pallidus, from three different geographical regions in South Africa

Cape White-eyes are widespread in South Africa, occurring in different climatic regions. We analysed primary moult data for large samples of this species from three geographical regions. There were no apparent long-term changes in duration or timing of moult during the nine years that the Western Cape results were collected, but sites within this region had different mean starting dates for primary moult. The Eastern Cape and Free State birds began moult about a month later than those in the Western Cape. This correlated well with the earlier breeding season in the Western Cape, and there was no evidence of overlap between moult and breeding. Mean primary moult duration was not significantly different among the sites or regions, and may be a species-specific trait. There was no evidence of regular long-distance movements in this species.

Molecular and biological characterization of molt-inhibiting hormone of Penaeus monodon

The action of molt-inhibiting hormone (MIH) on the inhibition of ecdysone release from the Y-organ of decapod crustacean keeps the animal in the intermolt stage that dominates its molting cycle. MIH is thus one of the major keys in mediating growth and reproduction. This study has isolated cDNA encoding two types of MIH, Pem-MIH1 and Pem-MIH2, from the black tiger shrimp, Penaeus monodon on the basis of sequence homology to MIH from two other shrimp species. The full-length cDNA of Pem-MIH1 was characterized. Pem-MIH1 cDNA harbored 318 bp open reading frame that coded for a translated product containing 28 amino acids of the signal peptide and a putative mature Pem-MIH of 77 amino acids. The recombinant Pem-MIH1 was expressed in Pichia pastoris as a secreted protein. After purification by gel filtration, the purified Pem-MIH1 exhibited the ability to extend molting duration of P. monodon from 11.8 days to 16.3 days suggesting that Pem-MIH1 be responsible for molt-inhibiting function in the shrimp. The attempt to clone Pem-MIH1 and Pem-MIH2 genes was achieved by direct PCR amplification and PCR-based genome walking strategy, respectively. The structure of both Pem-MIH genes, containing three exons interrupted by two introns, was similar to each other and also to that of MIH genes of other crustaceans reported so far. Expression study of Pem-MIH1 and Pem-MIH2 in various tissues of P. monodon revealed the difference in expression patterns. Pem-MIH1 expressed in both the eyestalk and the thoracic ganglia whilst Pem-MIH2 expression was limited to the eyestalk. The expression of MIH in non-eyestalk tissue may suggest additional role of this hormone.

The effects of delaying the start of moult on the duration of moult, primary feather growth rates and feather mass in Common Starlings Sturnus vulgaris

In many species of birds there is a close relationship between the end of breeding and the start of moult. Late‐breeding birds therefore often start to moult late, but then moult more rapidly. This is an adaptive mechanism mediated by decreasing day lengths that allows late‐breeding birds to complete moult in time. This study asked how these birds complete moult of the primary feathers more rapidly, and the consequences of this on the mass of primary feathers. Common Starlings Sturnus vulgaris were induced to moult rapidly in one of two ways. In the first experiment, one group was exposed to artificially decreasing photoperiods from the start of moult, whereas the control group remained on a constant long photoperiod. The second experiment was a more realistic simulation. Two groups were allowed to moult in an outdoor aviary. One group started to moult at the normal time. In the other, the start of moult was delayed by 3 weeks with an implant of testosterone. The duration of moult was significantly reduced in both the group experiencing artificially decreasing photoperiods and the group in which the start of moult was delayed. The faster moult rate was achieved by moulting more feathers concurrently. The rate of increase in length of each of the primary feathers, and their final length, did not differ between groups. The rate at which total new primary feather mass was accumulated was greater in more rapidly moulting birds, but this was insufficient to compensate for the greater numbers of feathers being grown concurrently. Consequently, the rate of increase in mass of individual feathers, and the final feather mass, were less in the rapidly moulting birds. A 3‐week delay in the start of moult is not an unrealistic scenario. That this caused a measurable decrease in feather mass suggests that late‐breeding birds are indeed likely to suffer a real decrease in the quality of plumage grown during the subsequent moult.

Use and Validation of a Molt Score Index Corrected for Primary-Feather Mass

Abstract In European Starlings (Sturnus vulgaris), mass of new primary feathers increases linearly with time for most of the duration of molt (Dawson 2003). Here, we had two aims: (1) to confirm that mass of new primary feathers increases linearly in other species, and (2) to use that linear increase as the basis of a system to score the progress of molt. Increase in length of primary feathers during molt was recorded for captive Eurasian Magpies (Pica pica), Carrion Crows (Corvus corone), European Greenfinches (Carduelis chloris), and Eurasian Bullfinches (Pyrrhula pyrrhula). Wing shape differs among those species. Feather lengths during molt were converted into mass by using information on final feather length and mass and the distribution of mass from tip to base of feather. Rate of increase in total mass of new primary feathers was largely linear in all four species. A molt scoring method is described in which individual feather scores are weighted to account for the contribution of each particular primary feather's mass toward total primary-feather mass. When the method was tested on eight captive starlings, the increase in mass-corrected molt score was almost linear, unlike the increase shown by the standard scoring system, which exaggerated molt rate during the early part of molt and underestimated it later. In the four species studied here, mass-corrected molt score likewise closely tracked the actual increase in mass, unlike the standard molt score. Because it is based on feather mass, the method presented here is of greater physiological and energetic relevance than the standard method. Because the mass-corrected score increases more linearly with time, it has the additional advantage of enabling less complicated, and potentially more accurate, estimations of molt start dates and molt durations.

Timing and duration of moult in three populations of Purple Sandpipers Calidris maritima with different moult/migration patterns

Timing and duration of primary moult in three populations of Purple Sandpipers Calidris maritima were described and discussed in relation to the birds’ need to complete moult before the onset of winter, when resources are required for survival. We predicted that moult would be completed earlier by birds wintering at higher latitudes. The south Norwegian breeding population, which moults and winters along the coast of east Britain (54–57°N) had a mean starting date of 21 July for primary moult (16 July for females and 24 July for males), a mean duration of 61 days, and completed on 20 September. Resident Icelandic (64–65°N) birds had a mean starting date of 22 July for primary moult (17 July for females and 25 July for males), a mean duration of 51 days, and completed on 11 September. Birds moulting in north Norway (70°N) arrived in north Norway in suspended primary moult or without having started moult, and completed it there. They had a mean completion date of 2 November for primary moult (31 October for females and 3 November for males). Starting date and duration could not be estimated because some suspended moult for an undetermined period, but it was thought that they started in late August. It is likely that most originated from Russia. The onset of moult appears to be set by the end of breeding and there is little overlap in these two events. The earlier start of moult by females in all three populations may be because they abandon the males when the chicks hatch, leaving the males to attend the chicks. Although the duration of primary moult followed the expected trend, being fastest in north Norway and slowest in Britain, the onset of moult was so late in north Norway that they had an unexpectedly late completion date, despite their rapid moult. The late completion of primary moult in north Norway suggests that wintering in the far north may not pose the energetic constraints on Purple Sandpipers that had previously been supposed.

Polymorphic Flight-Feather Molt Sequence in Tufted Puffins (Fratercula Cirrhata): A Rare Phenomenon in Birds

Abstract Previous reports have stated that Tufted Puffins (Fratercula cirrhata) lose all of their flight feathers simultaneously (or nearly so) during flight-feather molt and replace them in no apparent order. In contrast, we found that captive second-year (SY) Tufted Puffins (1) typically require 15 and 10 days to lose their primaries and secondaries, respectively, during their first flight-feather molt, and an average of 21 days to lose all of their remiges; and (2) replace their primaries in either of two discrete sequences. In 9 of 13 birds, primary molt began at the innermost primary, P1, and progressed distally to the outermost functional primary, P10. However, in the remaining four birds, primary molt began in the middle of the primaries (P5-P7) and progressed both distally to P10 and proximally toward P1. Before the proximal wave reached P1, a second wave of molt was initiated at P1 and progressed distally, typically replacing P2 and P3 before reaching the proximal wave. Such polymorphism in flight-feather molt sequence is rare in birds, having been reported previously only in a few passerine species. Secondary molt began about 13 days after onset of primary molt and finished at about the same time as primary molt, resulting in a total duration of flight-feather molt of ∼54 days and a flightless period of ∼40 days.