Moult papers:

references, abstracts and comments. Where there is no abstract, an abstract has been written, where abstracts are too long they have been abridged, where the English is poor it has been improved. Abstracts/summaries in languages other than English have been translated into English, some extremely bad abstracts (and even headings) from Ringing & Migration have been corrected when called for. The comment is personal, it points out errors and possible follow-ups, it is begun: CP:

ascending (ascendent, ascendant) primary moult: begins with the outermost primary.
descending (descendent, descendant) primary moult: begins with the innermost primary.
distal primary: the most distant ones from the body
prebasic molt (am.) = postnuptial moult
proximal primaries: the ones closest to the body
transilient mode: from the last moulted remige there is a forward or backward jump, omitting one or several intermediary remex.
dorsal: on the back side
ventral: on the belly side

N, O, P, Q, R


Nadler, T. (1976, new ed. 1995): Die Zwergseeschwalbe. Neue Brehm Bücherei, Bd 495. Ziemsen Verlag, Wittenberg-Lutherstadt.

Newton, I. (1966): The moult of the Bullfinch Pyrrhula pyrrhula. Ibis 108: 41 - 87.

The distribution of feather tracts and their sequence of moult in the Bullfinch is described. The adult post-nuptial moult, which is complete, lasted 10 - 12 weeks, and the post-juvenile moult, which is partial, 7 - 9 weeks.Adult moult began with the shedding of the first (innermost) primary and ended with the replacement of the last. Variations in the rate of moult in the flight feathers were mainly achieved, not by changes in the growth rate of individual feathers, but in the number of feathers growing concurrently. The primaries were shed more slowly, and the onset of body moult delayed, in birds which were still feeding late young.
In 1962, the onset of moult in the adult was spread over 11 weeks from the end of July to the beginning of October, and in the two following years over the six weeks from the end of July to the beginning of September. The onset of moult was delayed by late breeding, which itself occurred in response to a comparative abundance of food in late summer, markedly in 1962. In all years, the first juveniles to moult started at the end of July, and the last, three weeks after the latest adults. Juveniles moulting late in the season retained more juvenile feathers than those moulting earlier.
During moult, adult and juvenile Bullfinches produce feathers equivalent to 40 % and 33 % respectively of their dry weights. In both, for much of the moult, an average of nearly 40 mgm, of feather material - some 0.6 % of their dry-weight - is laid down each day. The remiges of the adult comprise only a seventh of the weight of the entire plumage, and it is suggested that their protracted moult results not so much from their energy requirements, as from the need to maintain efficient flight. Variation in the rate of moult in the remiges was much less pronounced than in the body feathers. Bullfinches were less active during moult than at other times of the year. The weights of both adults and juveniles increased during moult.
The food during the moult period is described. In all years, most Bullfinches finished moulting just before food became scarce, even though this occurred at different times in different years. In one year, adults moulting latest in the season probably survived less well than those moulting earlier; the same was apparently true of the juveniles in all years. The timing of moult in the Bullfinch, and the factors initiating it, are discussed in relation to the breeding season and food-supply near Oxford.

Newton, I. (1968): The moulting seasons of some finches and buntings. Bird Study 15: 84 - 92

The BTO moult records for some finches and buntings are analysed. It is estimated that, on average, the Lesser Redpoll takes about 50 days to moult (Evans 1966), the Linnet, Twite, Siskin and Chaffinch 70 days, the Goldfinch 80 days and the Bullfinch and Greenfinch 85 days. There is, however, considerable variation between individuals of the same species.
There is also variation between species in the timing of moult and in the spread of date of onset. On average, Chaffinches start moulting several weeks earlier than the cardueline finches and the buntings; this may be linked with the fact that Chaffinches finish breeding earlier. Within a species, the spread results from some individuals breeding later in the year than others and delaying their moult accordingly.
There is no consistent relationship between the duration of moult in the different species and the number of primaries growing concurrently. This suggests that the growth rate of the primaries and the rate at which they are shed vary independently in the different species.
The BTO data extend the moulting seasons given by Witherby et al., by 6-12 weeks in the different species, and modify considerably the information given there for the time of moult in the Lesser Redpoll and Twite. In all species, the period of year when individuals may be found in moult is longer than their breeding seasons.
In general, those species which are partial migrants start moulting earlier and/or moult faster than the resident species. As a result the migrants have mostly finished moult by the end of September or early October and are ready to migrate then, while the residents are still in moult. The Chaffinch is an exception in that, although resident, it has an early and relatively fast moult.

Newton, I. (1968): The temperatures, weights, and body composition of molting Bullfinches. Condor 70: 323 - 332

The mean rectal temperature of adult Bullfinches remained fairly stable from before the start of moult until near its end, when it dropped about 1° C.(...)
The body feathers of juveniles serve for only 3-9 weeks (till postjuvenal molt) and are weaker (with fewer barbs and barbules) than those of adults, which last a year. On the other hand, the flight and tail feathers of juveniles, which are not renewed at postjuvenal moult, are just as substantial as those of adults. Between the end of one molt and the start of the next, nearly a year later,the body plumage of adults lost one-third of its weight; but in the flight and tail feathers the loss was negligible. The plumage was at is heaviest at that stage of molt when most feathers were growing.
Both adults and juveniles increased in weight during molt, and for some weeks afterward, through increases in all three body components: lean dry material, water, and fat. In addition, the water content of Bullfinches was higher during molt than at other times; the extra water was localized in the growing feathers, which, at peak molt, contained up to 7 per cent (1.1 g) of the total water in the bird.
A diurnal circle was superimposed on the seasonal trends. Whether molting or not, birds lost water, lean dry material, and fat overnight and replaced them during the day. Moreover, the diurnal fat cycle increased in amplitude, irrespective of molt, as the season advanced and nights became longer and colder. In contrast the diurnal cycle in lean dry material was much greater in amplitude during heavy molt than at other times. It is suggested that at peak molt the breakdown of body protein occurred overnight (and was replaced during the day), and that the amino acids so released might be used partly to support feather growth which continued at the same rate as by day.
By analogy with data from chicken feathers, the total amino acids required for feather synthesis by molting Bullfinches was calculated. It is concluded that the total protein required for feather growth is probably set by its cystine content, for this amino acid is present in feather keratine at much higher concentration than in the proteins of plant seeds, on which Bullfinches feed during molt. Possibly, the birds can lighten the demand for cystine by synthesizing it from surplus methionine.
Adult Bullfinches produced about 2 g of feathers during a molt of 11 - 12 weeks, and juveniles 1.5 g in 7 - 9 weeks; in both, keratin was synthesized, on average, at 27 mg per day.
From carcass analyses, it seems that Bullfinches were able to meet entirely the nutritional demands of molt from food eaten at the time; they did not show the long-term protein deficit associated with the molts of certain species, and had fat contents as high as did nonmolting birds caught at the same time.

Niethammer, G. (1970): Zur Mauser der Ringeltaube (Columba palumbus). J. Orn. 111: 367 - 377.

(...)Primaries. Adult birds, from the latter third of April until early December, molt their primaries in a descending order from P1 to P10. Juveniles from late clutches interrupt the descending moult of their primaries latest by early January and continue the sequence in April. Some of them begin a new molting sequence already by the end of April (in synchrony with the molt in adults), shedding the 2nd generation P1 for the 3rd generation P1. Unless the 1st generation molt is completed by this time, the molt of the immatures is "telescoped" with a plumage at one time composed of three generations of feathers.
Secondaries. The secondaries are shed convergently from the outer- and innermost feather toward S6. However, this molt is frequently incomplete and leads to considerable irregularities in the timing and state of the cycle.
Rectrices. in young birds the molt of the rectrices starts with the innermost R1, commonly after P6 is shed. The sequence is very irregular and follows no specific pattern.
There appears to be no correlation between molt and reproduction. Immature birds intiate another molt of their primaries while still on their northward migration. Low temperatures at the onset of winter block the shedding of inner primaries and may cause a three-month delay.

Nikolaus, G. & D. Pearson (1991): The seasonal separation of primary and secondary moult in Palaearctic passerine migrants on the Sudan. Ring. & Migr. 12: 46 - 47.

In six Palaearctic passerine species caught in autumn on the Sudan Red Sea coast, adults with fully moulted primaries still retained most or all of their old secondaries. This seasonal split of the moult of the two flight feather tracts is discussed, and the strategy is compared with more typical moult suspension.

Niles, D. M. (1972): Moult cycles of Purple Martins Progne subis.. Condor 74: 61 - 71. Internetversion av denna uppsats.

The physical pattern of the molts of Purple Martins is briefly described. Postnuptial and postjuvenal molts begin in late July to early August in northeastern North America, are largely or entirely interrupted during the overwater portions of the autumn migration, and are resumed and completed on the South-American wintering grounds. The late summer, northeastern North American portion of the postjuvenal body molt is less intensive and/or temporally retarded relative to the postnuptial body molt of older birds. Unlike first-year birds and adults, juveniles do not renew any remiges or rectrices during the late summer period. First-year and adult males complete the late summer body molt earlier than do first-year and adult females. Remex molt of first-year martins is less extensive than that of adults during the late summer period. In South America molt by first-years and adults is resumed, on the average, in late September and completed about the end of February. Specimens completing the molt span the period of late January to early April. The postjuvenal molt is probably not completed, on the average, until mid-April. Breeding and molt by Purple Martins do not appear to overlap in time. Though the occurrence of overwater migration and molt appear to be largely mutually exclusive, at least part of the continental portion of the southward flight may be taken while molting.

Norman, S. C. (1990): Factors influencing the onset of post-nuptial moult in Willow Warblers Phylloscopus trochilus. Ring. & Migr. 11: 90 - 100.

A long-term study (1975 to 1989) on a population of Willow Warblers showed that in each year the majority of male birds commenced post-nuptial moult before females. It is suggested that this was due, in part, to an annual rhythm in moult onset and was fine-tuned, in both sexes to different degrees, during their first summer by other endogenous factors possibly linked to breeding. The majority of males commenced moult in June, regardless of whether replacement or second broods were being reared in July, but females synchronised onset of moult to the independence of their young. Two late breeding females suspended moult until their young were independent. Photoperiod alone probably had no bearing on the onset of moult in the majority of birds, but this factor may influence the rate of moult in late moulting individuals. Suspension of moult before migration probably involves late breeding females (...)

Norman, S. C. (1991): Post-juvenile moult in relation to dispersal and migration in the Chiffchaff Phylloscopus collybita. Ring. & Migr. 12: 80 - 85.

An examination of 191 juvenile Chiffchaffs in Cleveland, north-east England showed all birds renewed body, head and tail covert feathers during post-juvenile moult. Replacement of inner greater coverts, tertials and central tail feathers occurred in the majority of birds. Start of moult occurred at around 53 days of age and finished about 45 days later. Premigratory dispersal took place before or in the early stages of moult and during mid-moult birds remained sedentary with migration occurring as birds finished moult. Body weights associated with migration are discussed speculatively.
Commencement and extent of moult was more similar to that of Blackcaps than other warbler species previously studied (Norman 1981, 1990). It is suggested this was influenced, in part, by the shorter migrations of Chiffchaffs and Blackcaps to their winter quarters.

Norman, S. C. (1991): Viewpoint. Suspended split-moult systems - an alternative explanation for some species of Palearctic migrants. Ring. & Migr. 12: 135 - 138.

(from text) "It is therefore debatable whether suspended moult is in fact the true moult strategy once a proportion of feathers were renewed in the secondary tract. If a bird renewed all primary feathers and 1 - 3 outer secondaries (tertials moulted early) and then interrupted moult due to environmental factors some cue would be required to induce moult at the 4th secondary once the winter quarters were reached. This delay may be weeks to months of duration.
Taking one species as an example, Willow Warblers caught in Iberia and Crete during migration showed a variable amount of interrupted secondary moult (Mead & Watermough 1976, Swann & Baillie 1979). This was also mentioned by Lapshin (1988) for some birds in north-west Russia prior to autumn migration. Can the above be classed a 'split' suspended wing moult strategy when this species is known to commence a full winter moult in December (...)? In addition to this, birds would already have succeeded in reaching Africa with old feathers present in the wings."
[CP]: Norman is capable of thinking, there are a couple of such authors in the field of moult study; all he has written should be read with attention to detail.


OAG Münster (1975): Zug, Mauser und Biometrie der Bekassine (Gallinago gallinago) in den Rieselfeldern Münster. J. Orn. 116: 455 - 487.

During the last 13 years (1962 to 1974) the numbers of waders resting during off migration periods (= southbound; CP) have increased so much that the sewage farms of Münster have become the most important resting and moulting ground for the snipe in inland central Europe. During peak migration in September, about 2500 - 4000 individuals of this species rest there, up to 40 % of which are adults. From 1969 to 1974 data were collected from 1289 captured birds. The relationship between migration and moult as well as biometry and the weight changes are described.
1. Throughout the off migration periods, 1st year birds outnumber adults. The peak occurrence of adults correlates with the peak of the off migration during mid September. Analysis of the daily numbers of resting snipes and of weight changes reveals that the off migration of 1st year birds is performed in 2 phases.(...)
4. In the study area 1st year birds moult the body feathers, the wing coverts, some of the rectrices and the tertials (secondaries 11 to 15, numbered ascendently). Like adults, 1st year birds usually moult the tail feathers almost synchronously.
5. Many adults have already started their complete moult before they reach the sewage farms. The moult of the first 3 to 5 primaries (numbered descendently) obviously begins on or near the breeding grounds. Most individuals seem to finish it on the moulting ground after a short interruption caused by migration. (A) few of the moulting snipes, however, suspend primary moult here once more and presumably finish it on the wintering grounds.
6. The sequence of secondary moult of the snipe is different from that which has been published for other waders. Shortly before or after the 1st secondary has finished growing nearly all other secondaries (nos. 2 to 10, in half of the cases also 11) are shed simultaneously. The moult of the greater upperwing and underwing coverts is closely connected with this synchronous change of the secondaries: Before the secondaries are shed the greater upperwing coverts are completely renewed whereas the moult of the greater underwing coverts does not start before before the moult of the secondaries has been completed. So it is possible that the bird maintains its ability to fly during the complete secondary moult because then the new greater upperwing and the old underwing coverts replace them in their function.(...)

O'Hara, P. D., Lank, D. B. & F. S. Delgado (2002): Is the timing of moult altered by migration? Evidence from a comparison of age and residency classes of Western Sandpipers Calidris mauri in Panamá. Ardea 90: 61 - 70.

Resident species typically undergo post-nuptial moult directly following breeding, whereas long-distance migrant species usually do so after arrival at staging or non-breeding ("wintering") grounds. It has been suggested that moult and migration are mutually exclusive activities. If so, one will displace the other in time. We contrasted the moult timing of migrant versus non-migrant Western Sandpipers Calidris mauri, taking advantage of the fact that in Panamá, most yearling birds (11 - 22 months of age), and some adults, were non-migratory summer residents. Yearling birds and other summer residents completed primary moult approximately 3 - 4 weeks earlier than adults returning from the breeding grounds. The same general pattern occurs with contour moult. Some adults of unknown migratory status also have moult patterns similar to summer residents. We interpret these patterns as indicating that earlier moult is advantageous, partially compensating residents for not migrating and breeding that year. We consider potential mechanisms that may favour an earlier moult, and discuss how moult schedules may influence Western Sandpiper migratory and life history strategies.

Orell, M. & M. Ojanen (1980): Overlap between breeding and moulting in the Great Tit Parus major and Willow Tit P. montanus in northern Finland. Orn. Scand. 11: 43 - 49.

The timing of the moult was studied in 386 Great Tits and 46 Willow Tits in Oulu, northern Finland, in 1969-77 and 1970, 1975-77 respectively. The birds were also weighed during and after breeding.
The Willow Tits started moulting about 3 weeks earlier than the Great Tits. The moult was retarded by 2 - 3 weeks in the latter species when compared with populations further south. Male Great Tits started moulting before females, and completed the primary moult in approximately 74 days. The corresponding value for females was 70 days. The moulting period of the Great Tit population covered approximately 105 days.
The Willow Tits started moulting more frequently during breeding than did the Great Tits. However, in the latter species this overlap was more pronounced than further south. It is suggested that the early start and termination of moult in the Willow Tits are due to the fact that the tits must have time to collect their winter food storages in autumn.
The weights of the tits tended to increase during moult.

Oring, L. W. (1968): Growth, molts and plumages of the Gadwall. Auk 85: 355 - 380. Internetversion av denna uppsats

Gadwall embryological development parallels that of the domestic Mallard for the first 18 days. Papillae appear at 9 days and some pigment is visible by 10 days. At 13 days embryos are covered with papillae and filaments, and tarsal scales are visible. Ducklings emerge after 24 days. At hatching Gadwalls are mostly cream-buff below and sepia above. The yellowish tinge is probably due to carotenoids. Fading most likely is the result of carotenoid auto-oxidation catalyzed by heat and light. Feather wear also alters down color.
Follicles destined to produce Juvenal feathers are evident beneath the skin at 4 days. Juvenal down pushes through the skin at 7 days, Juvenal rectrices at 8 days. Side feathers also appear early. All wing feathers are among the last to grow. Most birds fly at 50 to 56 days of age. Late-hatched Gadwalls fly at a younger age than do early-hatched birds. Juvenal plumage is characterized by square-tipped rectrices, narrow body feathers, and dull wing color. Venters of both sexes usually have brown markings.
Feathers of the Basic I plumage, present principally on the breast and sides, are found from mid-Augusthrough December. They first appear just before the Juvenal plumage is completed, and are soon replaced. They may be told from Juvenal feathers by their broadness. A few follicles destined to produce Alternate I down are active beneath the skin by 35 - 46 days of age. A few follicles of Alternate I pennae are growing by 63 days. By 72 days, ventral Alternate pennae and down are evident exteriorly. Head and neck pennae, rectrices, and tertials of the Basic I plumage are the last to drop out. Alternate I tail feathers grow in males from mid-September to early February, in females from late October to mid-January. Males renew their tertials from late November to early February, females from 1 February to 4 June. Juvenal back and upper rump feathers are almost always retained; others often are. Retained Juvenal feathers, together with Juvenal wing feathers (except tertials), are worn simultaneously with the Basic I and Alternate I plumages. Male Alternate plumage is characterized by sharply contrasting patterns of dark gray and white. Venters are usually immaculate. In the female dorsal feathers are dark brown narrowly edged with buff, the throat and chin are dark, and the venter is nearly always immaculate. The Prebasic II molt of drakes usually begins in late May or early June. Breast and side feathers molt first. Lower back and rump feathers are among the last to molt and some may be retained. Tail feathers are usually molted from mid-July to late August, tertials from early July to late August. The rest of the wing generally is molted a few days after the tertials. The Prebasic II molt of hens (body and tail) occurs from January to May but is heaviest in March and April. Dusky venter down appears in late April and May after pennae are grown. Wing feathers are retained until the young are about 6 weeks old. The male's dull brown Basic II plumage is similar to the Juvenal plumage but the breast has larger dark spots. About half the birds have dark venter markings. Females in Basic II plumage are similar to those in Alternate II except that the chin and throat are buffier and the body feathers are broadly edged with buff. Females in Basic II plumage also are broadly edgedwith buff.
The sensitivity of feathers to molt-inducing substances varies with the age of the feathers. Probably normal molt is an autonomous process controlled within the feather papillae and some factor(s) associated with gonadal development inhibit(s) this process. Feather development can be arrested during the early phases of follicular growth by abnormal environmental conditions. The dull pattern of the male's. Basic plumage is probably induced by estrogens produced by the testes. In drake Gadwalls Basic feathers have been found growing from 15 May to 20 July. Pigment deposition during the rest of the year produces an Alternate pattern.

Ottosson, U. & F. Haas (1991): Primary moult of the Brambling Fringilla montifringilla in northern Sweden. Orn. Svec. 1: 113 - 118.

The postnuptial wing moult of the Brambling was studied in a subalpine forest near Ammarnäs (65°58'N, 16°07'E) in Swedish Lapland. 580 moult cards were collected during an annual ringing scheme in the years 1984 - 1989. Regression analysis of moult data, with date as the independent date, showed an average moult duration for males and females of 47 days. Raggedness values support the moult speed estimated from the regression analysis. The moult speed shown here for the Brambling is much faster than for the Chaffinch and might be due to some constraint for moulting during early autumn.

CP: QUOTE: Duration of moult was analysed by linear regression analysis with date as independent variable (...) when the trapping season fails to cover the whole moulting period (this) gives the best estimate for an average individual's moult duration (E. Haukioja, pers. comm.). Ottosson's and Haas's paper served as inspiration for Holmberg (1992), see above.

Owen, M. & M. A. Ogilvie (1979): Wing molt and weights of Barnacle Geese in Spitsbergen. Condor 81: 42 - 52.

(...)Most classes of geese lost weight gradually during molt but females who nested unsuccessfully made significant gains. We suggest that birds beginning the molt with large fat reserves are at an advantage in depleting these because lighter birds have a shorter flightless period. Geese beginning molt in poor condition (many of the yearlings in our sample) would suffer if feeding and weather conditions were unfavourable.
We argued that non-breeders molt early in order to maximize the time available for acquiring reserves for autumn migration. Post-molting geese are able to use better feeding areas and a sample recaptured in autumn had gained up to 500 g in weight following molt.
We hypothesize that many goose species undergo a long nothward molt-migration because it enables them to molt at the beginning of the growing period in these areas, when the vegetation is more nutritious and more easily digested.

Owen, R. B. Jr. & W. B. Krohn (1973): Molt patterns and weight changes of the American Woodcock. Wilson Bull. 85: 31 - 41.

A study of molt and changes in body weight of American Woodcock was conducted to better understand the summer and fall behavior of these birds and to indicate periods of physiological stress. The postnuptial molt of adults was a complete molt beginning in late June and ending by the middle of October. In contrast, the postjuvenal molt was a less intensive partial molt beginning in mid-July but also extending to the middle of October. Both male and female adult birds experienced weight loss in August during peak molt. Young birds gradually gained weight throughout the summer. Fat deposition was negatively correlated with molt while fall body weights were positively correlated with fat deposition. The data indicated that the majority of Maine woodcock are not physiologically prepared for migration until mid-October. Weights of adult males during the spring suggested that this is an important period of stress for these birds.


Paton, D. C. & B. J. Wykes. (1978): Re-appraisal of moult of Red-necked Stint in southern Australia. Emu 78: 54 - 60.

Payne, R. B. (1972): Mechanisms and control of molt. In: Farner, D. S. & J. R. King, 1972: Avian Biology, Vol. II, pp. 103 - 155.

Pearson, D. J. (1973): Moult of some palaearctic Warblers wintering in Uganda. Bird Study 20: 24 - 36.

An account is given of the plumage state and moult of some 1,100 Palaearctic warblers trapped at Kampala in southern Uganda.
Wintering Garden and Willow Warblers moulted completely, most birds commencing in late December or early January and finishing in March. Most Sedge Warblers, on the other hand, arrived in fresh plumage, having completed moult elsewhere in late autumn. Wintering Reed Warblers comprised two groups. One, consisting mainly of young birds, arrived in worn plumage and underwent moult in the area; the other arrived in fresh plumage during december and January.
Garden Warblers, Willow Warblers and most locally moulting Reed Warblers finished shortly before spring migration, and departed with their plumage in fresh condition. The majority of the wintering Acrocephali, however, commenced spring migration with their flight feathers already slightly worn. Sedge Warblers (but not Reed Warblers) commonly replaced much of the body plumage in early spring.
The usual duration of primary moult was estimated at 65 - 75 days in the Garden Warbler, 70 - 80 days in the Reed Warbler and 65 - 80 days in the Willow Warbler. Thus moult in Uganda winter quarters is much more leisurely than post-nuptial moult on breeding-grounds which occupies 30 - 50 days in the Willow Warbler.

Pearson, D. J. (1974): The timing of wing moult in some Palearctic waders wintering in East Africa. Wader Study Group Bull. 12: 6 - 12.

Pearson, D. J. (1975): Moult and its Relation to Eruptive Activity in the Bearded Reedling. Bird Study 22: 205 - 227.

Bearded Reedling moult data from the Walberswick, Suffolk, colony are analysed and discussed.
Most juveniles begin a complete moult between late July and early September, finishing between early September and early October. By reference to iris colour it has been possible to age young birds approximately, and to deduce the usual timing and duration of moult in birds with different fledging dates.
Young birds begin to moult in order of age. However, early fledged birds are several weeks older at its commencement than are late fledged birds, and take somewhat longer to complete. Most birds from normal first broods commence in late July, some 8 - 9 weeks after fledging, and take about 50 - 58 days. Most second brood birds appear to commence in mid-August, about 5 - 6 weeks after fledging, and take only 43 - 50 days. Birds commencing in late August and september, presumed to be mostly from third broods, are apparently only 2 - 4 weeks fledged; some of these moult in less than 40 days.
Post-juvenile moult in various feather tracts is described. Late birds moult faster than early birds by growing more feathers concurrently, rather than by growing individual feathers more rapidly. Replacement of the contour feathers is remarkably synchronised, and many of the long body plumes take six weeks to grow.
Most adults begin to moult between the end of July and mid-August, and begin to emerge from moult from the third week of September; duration appears to be 45 - 55 days, the same as in juveniles moulting at the same time. The pattern of moult and the manner of replacement of the body feathers are similar to those of young birds.
Activity in the Walberswick marsh in late summer and early autumn is described. Juveniles engage in excited flocking and calling in July before moult; this is renewed as birds reach the final stages of primary replacement. Fully moulted birds disperse to the marsh edges, and begin to engage in 'high-flying' behaviour. Activity increases throughout September, and departure from the marsh usually begins during the fourth week of the month.(...)

Pearson, D. J. (1981): The wintering and moult of Ruffs Philomachus pugnax in the Kenyan Rift Valley. Ibis 123: 158 - 182.

Some 5700 Ruffs were ringed in the southern Kenyan rift valley during 1967-79, mainly at Lakes Nakuru and Magadi. These have produced 15 recoveries outside East Africa, 14 in Siberia between 73 and 154 degrees E and one in India.
Adult males returned to Kenya mainly during August and females during late August and early September. Females greatly outnumbered males at all times. Most wintering males departed late in March and early in April, but females not until about a month later. First-year birds appeared from the end of August, but remained in low numbers until late October or November. Most departed during April and May, but a few females oversummered. First-year birds typically accounted for about 25 % of the wintering Nakuru females, but about 50 % of those at Magadi. At both sites they accounted for a higher proportion of male birds than females.
Most of the birds at Nakuru throughout late August to May appeared to be local winterers, and many individuals remained in the area for many months each year. Retrapping indicated that approximately 60 % of each season's birds returned the following season.
Adult males and most adult females commenced pre-winter wing moult before arrival, but completed most of it in Kenya. Males moulted 3-4 weeks ahead of females, and most had finished before December. Females typically finished during December and early January. Most second year birds timed their pre-winter molt similarly to older adults. Suspension was recorded in over 15 % of all moulting birds examined. Adult pre-summer moult involved most or all of the tertials, some or all of the tail feathers, most of the inner wing coverts and the body and head plumage. It occurred mainly during January to March (males) or February to April (females), although tertial renewal commonly began a month earlier. Males showed no sign in Kenya of the supplementary prenuptial moult.
First-year birds moulted from juvenile into first winter body plumage during late September to November. They underwent a pre-summer moult similar in extent and timing to that of adults, and again about a month earlier in males than females. Spring feathers acquired were often as brightly coloured as those of adults. About 15 % of first-year birds renewed their outer 2-4 pairs of large primaries during January to April.
Adult and first-year birds fattened before spring departure, commonly reaching weights 30-60 % above winter mean. Weights of adult males peaked early in April, those of adult females early in May, and those of first-winter females later in May. Weights were relatively high also during August and September. This was due to the arrival of wintering birds carrying 'spare' reserves, and also apparently to the presence of a late moulting fattening passage contingent.
The wing length of newly moulted adults was about 3 mm longer than that of newly arrived first-year birds, but there was no evidence of an increase in the wing length of adults with successive moults. Adult wing length decreased by 4-5 mm between the completion of one moult and the middle stages of the next.(...)

Pennington, M. G., I. P. Bainbridge & P. Fearon. (1994): Biometrics and primary moult of non-breeding Kittiwakes Rissa tridactyla in Liverpool Bay, England. Ring. & Migr. 15: 33 - 39.

During 1977 to 1984 a total of 762 non-breeding Kittiwakes were trapped between April and September at a site on Liverpool Bay, England. Ageing criteria are described. Mean wing-length and bill-depth increased with age, but only measurements of first-year birds were significantly different from other age classes. Neither bill-length or tarsus-length showed any variation with age. Mean weights of first-year birds tended to be lower than those of older birds and there was evidence of body weight loss during the summer, possibly due to the stress caused by the progression of moult. Median primary moult scores of first- and second-year birds were significantly higher than those of older individuals. Primary moult takes place between May and October but estimation of its duration was unreliable due to the restricted range of data, with estimates varying between 106 and 187 days. A figure of ca. 130 days is suggested.(...)

Persson, C. (1977): The early stages of the postnuptial moult in the White Wagtail Motacilla alba. Orn. Scand. 8: 97 - 99.

When their breeding is finished, adult White Wagtails leave their territories and spend the night in common roosts. At the same time the postnuptial moult sets in. Some birds, especially females, start moulting while still conducting young from the second brood in the territory. A comparison reveals that there is little difference in moult status between birds caught on roosts and birds caught on territories.

Pesente, M, P. Maragna & E. Cerato (1997): Records of complete post-juvenile moult in the Reed Bunting Emberiza schoeniclus in north-eastern Italy. Ring. & Migr. 18: 68 - 69.

(from text) "Over 80 % (22/27) of juvenile Reed Buntings of the intermedia form trapped between 15 July and 30 September 1994 were actively moulting wing feathers. Of the 27 juvenile birds handled in an advanced or final stage of moult, about 50 % (13/27) showed the same sequence of wing and tail feather renewal as the adults; about 30 % (9/27) had changed 5-7 outer primaries, 3-4 innermost secondaries, tertials and rectrices. Finally, five birds had renewed tertials and some rectrices." ( The same pattern: irregular moult involving at least tail, tertials and all or some secondaries, applies to first-brood birds in southernmost Sweden as well, so it is not specific to intermedia. On the other hand, I have not seen growing primaries in 1y Reed Buntings in Sweden.

Piechocki, R. (1961): Über die Grossgefiedermauser von Schleiereule und Waldkauz. J. Orn. 102: 220 - 225.

Two Barn Owls, born in June 1957, were kept in a large aviary for several years. The process of wing and tail moult was closely followed and proved to be very complicated.
The first primary to drop was the sixth (from within), which was followed aftyer 46 days by the seventh. All the rest of the ten primaries were shed in 1959 and 1960. This was the sequence: 6-7-8-9-10 and parallel to this from 7: 5-4-3-2-1. The chronological rhythm of the proximal series (5 to 1) was independent from that of the distal series (7 to 10). In 1960 the third generation of primaries started to grow, beginning once more with the sixth and, in the same year, ending with the tenth; but the proximal series remained unaffected. At the end of 1960 the primaries were thus of different rank and age, some belonging to the third, others to the second generation.(...)
The secondaries followed a sequence not essentially different from that of other owls (Strix, Athene); however, the moult of the first generation was very much protracted. It began in 1958 and ended in 1960. Some of the juvenile secondaries reached an age of three years.
The tail moult started in 1958 with the outer and innermost pair; the rest followed in 1959. No tail feathers were moulted in 1960.
With the Tawny Owl (Strix aluco) the moult is far simpler. Two birds taken from the same nest at the end of April 1959 moulted all ten primaries in 1960 following the descending mode, and practically all secondaries in the same sequence as Athene. The twelve tail feathers dropped within a few days.

Pienkowski, M. W., Knight, P. J., Stanyard, D. J. & F. B. Argyle (1976): The primary moult of waders on the Atlantic coast of Morocco. Ibis 118: 347 - 365.

(...)Similar rates of primary feather replacement relative to specific moult duration were observed in all species for which information was available. Comparisons between species and with published studies showed that variations in rate of moulting between species and between different geographical populations of the same species were largely due to differences in feather growth rate rather than in the number of primaries concurrently in growth. Variations in rate between individuals of the same population were achieved, at least in the first part of moult, by differences in feather dropping rate resulting in differences in the numbers of primaries growing concurrently.
(...)Most Redshank and possibly Dunlin migrated in active wing moult.

Pimm, S. L. (1970): Swallows in wing-moult in Southern Spain. Bird Study 17: 49 - 51.

Pimm, S. L. (1973): The Molt of the European Whitethroat. Condor 75: 386 - 391.

The timing and duration of primary, secondary and tail molt and their relation with one another are discussed, and the conclusion is drawn that some British Whitethroats leave the country with incompletely replaced secondaries. (...) Birds caught on the continent, in Iberia, with arrested molt were shown, at least in 1967, not to be replacing their old secondaries. Since areas in Iberia have produced recoveries of adult birds from Britain, it is thought likely that some British birds migrate to their winter quarters with arrested molt.

Potts, G. R. (1971): Moult in the Shag Phalacrocorax aristotelis, and the ontogeny of the "staffelmauser". Ibis 113: 298 - 305.

There are three main types of plumage in the Shag, the juvenal which is brown, the post-juvenal which is dark brown and the nuptial which is black-green. The replacement of these plumages and the ontogeny of the Staffelmauser was studied in a sample of 566 Shags mainly from northeast England. The replacement of the juvenal primaries starts at the age of eight months with the loss of the innermost primary and continues outwards at a rate of about one primary per 17 days. Another cycle starts when the first reaches the 8th primary but both cycles soon pause for the winter. Successive cycles are established anually in August or September in this way, so that cycles which take longer than one year to complete result eventually in a Staffelmauser in which each feather is replaced once annually. Most individual Shags in a breeding population will retain feathers from two or three cycles, but a large sample of breeding adults of the same age will retain feathers of four cycles.
The winter pause is considered an adaptation to the increased probability of adverse conditions at this time. The system described for the ontogeny of the Staffelmauser is applicable to those other sea-birds which have been studied in detail, and is probably advantageous since it combines slow moult during the difficult early years with a highly efficient moult during the breeding years, especially where moult and breeding occur together.


Raitt, R. J. (1961): Plumage development and molts of the California Quail. Condor 63: 294 - 303. Interbnetversion av denna uppsats

Young California Quail (Lophortyx caZifornicus) are hatched with a covering of natal down. This down is replaced in a regular sequence by the juvenal plumage during the postnatal molt. Juvenal plumage development lasts from the time of hatching until the age of about 11 weeks. The juvenal plumage is replaced by the first winter plumage during the postjuvenal molt, which commences at the age of four weeks. The first winter plumage is fully developed by the age of 21 to 23 weeks. The greater primary coverts and primaries 9 and 10 of the juvenal plumage are retained for about a year and are molted in the first postnuptial molt. The sequence of feather replacement is similar in all molts except that the head plumage is replaced late in the postnatal molt whereas the head begins molting early in the postjuvenal, and presumably in the postnuptial, molt. The regular replacement of the series of remiges, especially the primaries, may be used as a gauge to determine the age of the young quail. Adult quail undergo one complete molt each year at the end of the breeding season. The adult males begin to molt early in June, and the females follow about a month later. Inception of molt in individual hens is apparently governed by the hatching of their young. Females replace their plumage in a shorter time than do males; both sexes complete the molt in late October.

Richards, P. R. (1976): The onset of moult in the Rook. Bird Study 23: 212.

(from text) I have found that it is usually the case that my captive Rooks drop their innermost primaries, always the first feathers to be moulted, two or three days after the young leave the nest. If young of a late brood are still in the nest at the end of May, the male sometimes begins to moult before they fledge with associated loss of parental feeding behaviour.

Richter, A. (1972): Zum Umfang der Jugendmauser am Flügel der Amsel Turdus merula. Orn. Beob. 69: 1 - 16.

The extent of the partial postjuvenal wing moult of the Blackbird Turdus merula was studied from data provided by 611 immatures netted near Basel, Switzerland, from 20 October 1970 through 14 March 1971.(...) Marginal feathers, middle primary coverts, middle secondary coverts (with one single exception) and at least one greater secondary covert were always moulted. Replacements of the carpal covert occurred in 64 % of birds, of the proximal alula quill in 31 %, and of one to three inner secondaries 7 to 9 in 27 %. There was no instance of orderly moult of the primaries and their greater coverts or of secondaries 1 to 6. Accidental or sporadic replacement of one to several distal secondaries was recorded in 43 cases (8 %), of primaries in 7 cases and of primary coverts in 3 cases.(...) Out of 439 birds examined for both right and left wings 41 % showed asymmetric moult patterns. The lowest percentages of asymmetry were found for the carpal covert (7 %) and the inner alula quill (16 %), the highest for tertials (57 %) and the outer secondaries (96 %).

Riddiford, N. (1990): Tree Pipit with suspended or arrested moult. Ring. & Migr. 11: 104.

Rogge, P. R. (1966): Ein Beitrag zur Mauser des Rotkehlchens (Erithacus rubecula rubecula L.). Beitr. Vogelkunde 12: 162 - 188.

Ruge, K. (1969): Zur Biologie des Dreizehenspechts Picoides tridactylus L. 2. Beobachtungen zur Mauser. Orn. Beob. 66: 42 - 54.

In the examined nestlings of Three-toed Woodpecker the five inner primaries grew to a maximum length of 2 - 5 mm. At the age of about 8 - 13 days these primaries were moulted. The moult of P6a may follow shortly afterwards or is delayed. There is a wide range in size of P6a in different individuals. The other primaries are developed normally. The P10a was exchanged in September. The moult of rectrices was completed at the same time. In the juvenile moult the only secondary changed was S9a.(...)
By the reduction of primaries in the Three-toed Woodpecker the moult of the flight feathers can be completed earlier than in theGreat Spotted Woodpecker Dendrocopos major. In the Great Spotted Woodpecker only P1a and P2a are slightly shortened. The reduction may be interpreted as an adaptation to a special biotope.(...)


37 entries 16.2.06, links corrected 1.4.04.

  • Till ruggningsuppsatser A - F / To moult papers A - F
  • Till ruggningsuppsatser G - M / To moult papers G - M
  • Till ruggningsuppsatser S - Z / To moult papers S - Z
  • Till uppsatser om vikter, fett, energetik, A - K / To papers about fat, weights, energetics, A - K
  • Till uppsatser om vikter, fett, energetik, L - W / To papers about fat, weights, energetics, L - W
  • Till listan över backsvaleuppsatser / To list of Sand Martin papers
  • Till listan över gulärleuppsatser / To list of Yellow Wagtail papers
  • Till innehållsförteckningen för svalor / To hirundine contents
  • Till innehållsförteckningen för ärlor / To wagtail contents
  • Tillbaka till startsidan/Back to start page