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Plumage and Molt Terminology

Ron Pittaway

A knowledge of plumages, moltsand ageing is essential to the mod­ern birder. The identification of arare gull or shorebird often hingeson knowing its correct plumage andstage of molt. Determining a bird'splumage and molt is an identifica­tion challenge that will add new funand skills to your birding. It is alsoimportant to translate correctlybetween different terminologies.This article (1) defines the key gen­eral terms of plumage and molt,including the banding codes; (2)provides separate lists of birds thatmolt once and twice per year; and(3) compares a general terminologywith that of Humphrey and Parkes(1959). The Humphrey and Parkesterminology is recommended wherethere is a need to describe precisely abirdJs plumages and molts.

General TerminologyThe following terms are used com­monly by North American birders,but they are often used inconsistent­ly by authors and birders. Here, eachterm is given an exact meaning in anattempt to standardize the defini­tions. Plumage terms are definedfirst, followed by the terms for molt.

PLUMAGESImmature: A general and collectiveterm that includes juvenile, first

winter, first summer and all subse­quent plumages until the non­changing adult (definitive) plumageis acquired.

Juvenile or Juvenal: To avoid con­fusion, it is best to use these twoterms as having the same meaning.It is the first covering of true con­tour feathers following the nataldown(s), or in certain species it suc­ceeds the naked nestling stage with­out the natal down. Juvenile has aprecise meaning; it is the first imma­ture plumage. The juvenile plumageis worn briefly in most passerines,but much longer in loons, hawks,gulls, shorebirds and others. In mostbirds, the juvenile feathers appearlooser, woollier, and differentlycoloured and shaped than subse­quent stages. Some authors usejuvenile, but not juvenal, as havingthe same meaning as immature, justadding to the confusion. Otherauthors use juvenile as a noun andjuvenal as an adjective. For exam­ple, the juvenile is in its juvenalplumage. However, both words canbe used as nouns and adjectives. Seealso the definition of Juvenal in thesection below under the Humphreyand Parkes terminology.

First Year: This term applies tobirds that molt once per year. It fol-

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lows the postjuvenile molt and isretained until the first postbreedingmolt. First year birds do not haveseparate first winter and first sum­mer plumages. In many birds, firstyear plumage is worn from latesummer or early fall to the follow­ing summer. First year plumage isadult-like in many species, especial­ly passerines. Many breed in thisplumage. First year birds often canbe separated from adults byretained juvenile feathers. See thesections on Feather Generationsand Ageing below. First year is alsoused as a general term to includebirds in juvenile, first winter andfirst summer plumages.

First Winter: This is also called firstnonbreeding plumage. First winterplumage follows the postjuvenilemolt in birds having two plumages ayear. First winter plumage is retaineduntil the first prebreeding molt. Firstwinter is adult-like in some species,but many other species are separablefrom adults in the field. See also thesections below under FeatherGenerations and Ageing.

First Summer: This term does notrefer to a bird in the summer of itshatching year, but to the next sum­mer in its second calendar year.Remember this point to avoid con­fusion. It refers to that plumage fol­lowing the first winter plumage inbirds having two plumages a year. Itis acquired by the first prebreedingmolt and retained until the first

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postbreeding molt. First summerplumage is adult-like in mostspecies. Most passerines breed infirst summer plumage, but they arenot adults because they retain juve­nile flight feathers. Many first sum­mer birds are separable from adultsin the field by their duller or incom­plete plumage colour and molt con­trast. See the sections below underFeather Generations and Ageing.First summer is sometimes calledfirst breeding plumage. When youare unsure if the bird is in first sum­mer or adult breeding plumage, justcall it breeding plumage to includeboth age classes.

Secondffhird Winter: Some birdsthat have two molts per year, suchas large gulls, have recognizablesecond and third winter plumages.

Secondffhird Summer: Some birdsthat have two molts per year, suchas large gulls, have recognizablesecond and third summer plumages.

SecondffhirdlFourth Year: Somespecies have recognizable second,third and fourth year plumages.

Adult: Adult refers to a bird'splumage, not to whether the bird isof breeding age. A bird is adultwhen it acquires its final or defini­tive plumage that is then repeatedfor life. Birds that molt once a yearhave only one adult plumage; theyare not divided into adult winterand adult breeding plumages. The

sexes are often alike in birds havingonly one adult plumage and manyare dull and cryptic in colour. Birdsthat molt twice per year have twoadult plumages: adult winter andadult breeding. The sexes are oftendifferent, particularly the breedingplumage, in species having twoadult plumages. Most passerinesbreed in their second year beforethey acquire adult plumage; theyappear very adult-like but retainthe juvenile flight feathers. Accipterhawks frequently breed in their sec­ond year when they are in juvenileplumage. They are "adults" only interms of reproduction, but notplumage. Birds wearing anyretained immature plumage, eventhough breeding, are not adults.Note: adult used here is synony­mous with the term definitive ofHumphrey and Parkes.

Adult Winter: Birds that molt twiceper year have two adult plumages:adult winter and adult breeding.Adult winter plumage is also calledadult nonbreeding plumage.

Adult Breeding: Birds that molttwice per year have two adultplumages: adult breeding and adultwinter. Adult breeding plumage isalso called adult summer plumage,and in the old literature it wasknown as adult nuptial plumage. Inadult birds that have two distinctplumages, adult breeding and adultwinter, there are a very few specieswhere the sexes have identical

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plumages (e.g., loons).

Subadult: This is generally used todescribe birds whose plumage isnearly adult in appearance, butshows traces of immaturity. It ismost often used for birds that takeseveral years to reach adult ordefinitive plumage, such as eagles.This term is confusing and is bestavoided.

Eclipse: This female-like plumage isheld very briefly by ducks in sum­mer and early fall, and is mostnoticeable in the males. Eclipse isreally the basic or winter plumage,but is worn in summer by mostducks, except the Ruddy Duckwhich wears eclipse to late winter.Most ducks acquire breedingplumage in the fall, six or sevenmonths before other birds. Thisshift in the assumption of breedingplumage appears related tocourtship during fall and winter.

Calendar Year Terminology: Firstcalendar year refers to a bird up tothe 31 December of its hatchingyear. Second calendar year goesfrom 1 January to 31 December,and so forth. Large birds, such aseagles, are often aged using the cal­endar year.

MOLTSTraditional molt terms are postjuve­nal or postjuvenile, prebreeding andpostbreeding. These terms aredefined below. Complete molts

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replace all the feathers, sometimesinterrupted by a pause between peri­ods of molting. Anything less than acomplete molt is termed a partialmolt. Most partial molts replace thebody feathers, but not the wings andtail. Some partial molts are limited,usually replacing only a few headand/or body feathers. Depending onthe species, molts may be protractedsuch as in hawks, or suspended dur­ing migration and continued (offset)on the wintering grounds.

Postjuvenile Molt: This begins soonafter fledging in most passerinesand somewhat later in many non­passerines. It is a partial molt inmost birds, producing first winterand first year plumages. A very fewspecies have a complete postjuve­nile molt. These species usuallyacquire adult plumage directly fromthe juvenile plumage; for example,the Horned Lark becomes an adultat about three months of age.

Prebreeding Molt: Some specieshave a molt in late winter or earlyspring that produces a separate,often more colourful, breeding orsummer plumage. It is a partial moltin most species. A very few species,such as the Bobolink, have a com­plete prebreeding molt.

Postbreeding Molt: This is the com­plete annual molt found in nearlyall species. In many species, this isthe only yearly molt. It occurs afterthe breeding season in most species,

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but in other species it starts muchearlier or later. In some species, thepostbreeding molt takes place onthe wintering grounds after migra­tion. It produces a combinationwinter and summer (yearly)plumage in species that molt onceper year. In species that molt twiceper year, it produces the winterplumage. During the postbreedingmolt, there is often a noticeablechange in the behaviour of manybirds, particularly in passerines;they become quiet and lethargic,avoiding long flights, and spendingmore time resting and skulking.Knowing differences in the timingof molts among similar species canhelp identify a difficult species; forexample, some Empidonax fly­catchers molt before, and othersafter, fall migration.

Feather Generations: The feathersacquired by a molt, whether partialor complete, form a feather genera­tion. Most first winter and first yearbirds wear a combination of olderjuvenile and newer first winter feath­ers. First summer shorebirds oftenwear a combination of old juvenile,somewhat younger first winter andnew first summer feathers. Mostadult birds that molt twice per yearare wearing two feather generationsduring the nesting season. Juvenile,first year, first winter, first summerand adult feathers often have differ­ent patterns, colours, shapes, lengthsand amount of wear. Being able torecognize different feather genera-

tions is one of the keys to under­standing molt. Practice on pho­tographs, feeder birds, birds in thefield and even dead birds, but do notkeep them unless you are givingthem to a museum. A visit to a muse­um or university collection is veryinstructional.

Ageing: Age and plumage termsoften have the same meaning.Adult,juvenal, first summer, secondwinter and so forth are terms thathave both plumage and age mean­ings. However, a Herring Gull inadult winter (definitive basic)plumage could be as young as 3.5years in its first adult plumage or itcould be 25 years old because itsadult plumages change little withtime. Many passerines in adult-likeplumage, especially males, can beaged as first year, first winter andfirst summer by the molt contrastbetween their retained, brownerjuvenal flight feathers and thenewer blacker remainder of thewing. Examples of the latter arefirst summer male Rose-breastedGrosbeak (see Figure 1) and Black­headed Grosbeak, first summermale Western Tanager and ScarletTanager (see Figure 2), and firstyear male Eastern Towhee andSpotted Towhee. Feather contrastscan also be noted in dull species(e.g., sparrows), but one must havea close look and considerable expe­rience. This is an area where birderscan greatly expand their knowl­edge. See Pyle (1997) for detailed

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information on ageing. Finally,many species cannot be aged exact­ly in the field.

Feather Wear: In time, feathersbecome frayed and faded and thebird is in worn plumage. Speciesthat molt once a year in late sum­mer and breed the following springdo so in worn plumage. The EasternTowhee is a species in which thechanges due to wear are rarelynoticeable in the field. Somespecies, however, dramaticallychange their appearance andacquire their breeding dress bywearing off the tips of their feath­ers. The effects of feather wear onthe changing seasonal appearanceof birds are sometimes mistaken formolt. Early ornithologists calledthis molt by wear. The EuropeanStarling, House Sparrow and black­birds are examples of species thathave quite different fall (fresh) andspring (worn) appearances, but theyhave the same feathers. The SnowBunting is an extreme example ofchanging its winter to summerappearance by feather breakage. Inearly spring, the brown feather tipsbreak off as if cut by scissors, expos­ing a striking black and whitebreeding dress. The Snow Buntingattains the functional equivalent ofa breeding plumage without molt­ing; there is a very limited molt ofsome facial feathers, but this isinconsequential. The other extremeis the male Bobolink, which has acomplete prebreeding molt. In very

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Figure 1: Male Rose-breasted Grosbeak in first alternate plumage, told by retainedjuvenal brown instead of black primaries and secondaries. Photo courtesy ofPoint Pelee National Park.

fresh breeding plumage, it is cloud­ed over with buff, which soon wearsoff. In most cases, the freshplumaged birds in the fall are dullerbecause of gray or buffy feathermargins that wear off gradually,exposing a somewhat brighter ordarker plumage by spring.However, a few species are actuallybrighter in fresh fall featheringbecoming duller by spring (e.g.,Grasshopper Sparrow).

Confusing Terms: Some books useseasonal descriptions for plumagesand molts. Examples are fallplumage, spring plumage, summermolt and so forth, but these are not

o TARIO BIRDS APRIL 2000

official terms. They simply refer tothe time of year a plumage or moltoccurs. Immature ducks in winteralso cause problems with plumagenames because most are in thehomologous equivalent of breedingplumage. Eiders are often labelled as"first winter" in field guides when infact they are molting or in first sum­mer (alternate) plumage that is wornin winter! The European literatureoften uses first summer, second sum­mer and so forth for birds tha tacquire their summer appearance bywear only. Do not assume that theplumage labels in field guides andbirding journals are correct.

Banding CodesBird banders use an age code that islinked to the calendar year. Thiscode is used by the CanadianWildlife Service and the UnitedStates Fish and Wildlife Service.

U (unknown) is for a bird after thebreeding season and before 1January that cannot be placed inany of the age classes below. After31 December use Any.

L (local) is for a young bird inca­pable of sustained flight. Banderssometimes label these birds as Juv(juvenile), but it is not part of theofficial code.

HY (hatching year) is for a bird upto and including the 31 Decemberof the calendar year in which it washatched. It includes birds in juve­nile, first winter and first yearplumages. Banders sometimes usethe label Juv for birds that areclearly in juvenile plumage, but thisuse is not officially part of the code.

Any (after hatching year) is for abird in at least its second calendaryear or older. Year of hatch isunknown, but it is at least a SY.

SY (second calendar year) is forbirds in their second calendar yearfrom 1 January to 31 December.These birds are known to havehatched in the preceding calendaryear.

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ASY (after second year) is for abird in at least its third calendaryear. Year of hatch is unknown.

TY (third year) is for a bird knownto be in its third calendar year.

ATY (after third year) is for a bird(normally adult) in at least itsfourth calendar year. Year of hatchis unknown.

Humphrey and ParkesTerminologyThe molt and plumage terminologyof Humphrey and Parkes (1959) isused widely by North Americanornithologists in the professionalliterature; for example, Palmer(1962,1976,1988) in the HandbookofNorth American Birds, and morerecently in The Birds of NorthAmerica series. The AmericanBirding Association adoptedHumphrey and Parkes as the stan­dard in its journal Birding (Wilds1989). In Canada, the Ontario BirdRecords Committee uses theHumphrey and Parkes system in itsannual reports published in OntarioBirds. The Humphrey and Parkessystem can be used anywhere in theworld because it is not linked toage, seasons or breeding cycle. It is ajoy to use, once mastered.

Plumages: Plumages are namedjuvenal, basic, alternate and supple­mental. A new plumage is acquiredonly by a molt. Many birds wear

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more than one generation offeatherssimultaneously) but their plumage isalways named after the last acquiredgeneration. For example, a maleScarlet Tanager in definitive alter­nate (adult breeding) plumageretains its definitive basic (adultwinter) wing and tail feathers. Ifmales have a prealternate molt, thefemales also usually molt. But in thecase of the Scarlet Tanager, thefemale in basic and alternateplumages is similar.

Juvenal: This is the first generationor coat of true contour feathers fol­lowing the natal down or downs.Humphrey and Parkes (1959)retained the widely used term juve­nal from the earlier NorthAmerican literature. Juvenal refersto both the bird and its plumage; itis both a noun and an adjective. Toavoid confusion, I recommend thatjuvenal and juvenile be used as syn­onyms. Use juvenal if you want tobe sure of not being misunderstood.

Basic: The basic plumage usually fol­lows the juvenal plumage. See discus­sion below under Supplemental forexceptions. In species that molt oncea year, the basic is repeated as theonly plumage. The sequence is juve­nal molt to basic molt to basic moltto basic, repeated for the life of thebird. In birds that molt twice a year,the basic plumage is one of twoplumages: basic and alternate. Basicequals winter plumage only in birdsthat have an alternate plumage.

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Recognizable plumages may benumbered first basic, second basicand so forth to describe recognizableplumage stages until the definitivebasic plumage is reached. Basicplumage is acquired by a prebasicmolt. The first prebasic molt is a par­tial molt in most birds, replacing thebody feathers, but usually not thewings and tail. The second and subse­quent prebasic molts are complete inmost birds, replacing all the feathers.

Alternate: This is the name of thesecond plumage for birds that molttwice a year: basic and alternate.The sequence is juvenal molt tobasic molt to alternate molt to basicmolt to alternate, repeated for thelife of the bird. Alternate equalsbreeding or summer plumage.Recognizable plumages may benumbered first alternate, secondalternate and so forth until defini­tive alternate plumage is reached.Alternate plumage is acquired by aprealternate molt, which is usually apartial molt in most birds, replacingonly body feathers, but not thewings and tail. Alternate plumagesare brighter and more colourful inmany species, but in some the alter­nate is practically identical to thebasic. Note: birds that molt once ayear do not have an alternateplumage.

Supplemental: It was first defined asthe name of the third plumage whenthere are three molts per year. Thesupplemental plumage precedes or

follows the alternate, depending onthe species. There are a very fewspecies with more than two defini­tive (adult) plumages. It occurs inpelicans, Oldsquaw, ptarmigan and afew other species, and is acquired bya presupplemental molt. Note: Wenow know that supplementalplumages also occur in the first yearof life in birds that later have onlyone or two molts per year. Someyoung birds acquire a supplementalplumage before and/or overlappingwith the first prebasic molt.Examples are the Phainopepla,Yellow-breasted Chat, Passerinabuntings and Northern Cardinal.These species have a previouslyunknown sequence of molts andplumages that are probably morefrequent in other birds than current­ly known. The sequence for thesespecies is juvenal plumage, presup­plemental molt, supplementalplumage, first prebasic molt, andfirst basic plumage. Later supple­mental stages are apparently absent.When a new molt and plumage arediscovered, the procedure to nameit is to equate one of the plumageswith later basic plumages and tocompare it with basic plumages inrelated species to determine whichis the additional supplementalplumage. The uncommon supple­mental plumage is not treated in thecomparison chart below (Table 1).

Definitive: Definitive equals adultplumage, except that it is used onlyas an adjective. A bird can be an

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adult, but not a definitive! It is thefinal plumage that does not changefurther with age; all subsequentstages of the same plumage areidentical. It is an adjective: defini­tive basic plumage, definitive alter­nate plumage, definitive supple­mental plumage, and so forth.Definitive is also used to describemolts; for example, the definitiveprebasic molt.

Predefinitive: This is a useful collec­tive term with the same generalmeaning as immature defined previ­ously. Predefinitive refers to allplumages before the definitive stageis reached. Molts also may be termedpredefinitive. Humphrey and Parkes(1959) did not define predefinitive.

Molt Names: Molts are named interms of the incoming plumage:prebasic molt, prealternate moltand presupplemental molt. The fol­lowing are some examples of howto describe a bird in molt: (1) thejuvenal Bonaparte's Gull is begin­ning its first prebasic molt; (2) themale Scarlet Tanager is ending itsdefinitive prealternate molt; and(3) the Stilt Sandpiper is in themiddle of body molt from juvenalto first basic plumage, or you couldsay that it is in juvenal/first basicplumage. It is incorrect to say abird is in its prebasic plumage orprealternate plumage becausethese terms refer to molts, not toplumages.

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shedding and replacing of a bird'sfeathers. Regular molts in birds arenecessary because feathers wear outwith time, becoming less effectivefor insulation and flight. The juvenalUuvenile) is the first plumageacquired after the natal down. Theyoung bird then goes through aseries of molts and plumages untildefinitive (adult) plumage isattained. There are four main moltstrategies in definitive (adult) birds:

1.A complete molt renewing all feath­ers once a year, usually in late sum­mer or early fall after the breedingseason. This is called the definitiveprebasic (adult postbreeding) molt.

Molt Patterns: Some of the informa­tion de cribed below has beenrepeated from earlier sections forclarity. Molting includes both the

Figure 2: Male Scarlet Tanager in first alternate plumage, told by retained juvenalbrownish instead of blackish primaries and secondaries. Photo by JimFlynn.

Molt Equivalents: First prebasic moltequals postjuvenile molt, but notethat the second and later prebasicmolts equal postbreeding molts.Prealternate molt equals prebreed­ing molt. Humphrey and Parkes(1959) did not originally apply theterm definitive to molts, but it is nowused for the molts leading to defini­tive plumage . They are now calledthe definitive prebasic molt, defini­tive prealternate molt and definitivepresupplemental molt.

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2. Many other species have a com­plete molt as in (1) plus an addition­al partial molt of the head and bodyfeathers, usually in late winter orearly spring, acquiring definitivealternate (adult breeding) plumage.This is called the definitive prealter­nate (adult prebreeding) molt.Prealternate molts may haveevolved in some species to producea colourful courtship and breedingappearance. The vast majority ofbirds use molt strategies (1) or (2)above. The primaries, secondariesand tail of most birds are moltedonly once per year during the com­plete molt.

3. A very few species, such as theBobolink, have two complete moltsper year.

4. The Oldsquaw and a few otherspecies have three molts per year;the third partial molt is called thepresupplemental molt, leading tothe supplemental plumage. See dis­cussion above under Supplemental.Nate: In birds that develop broodpatches, the feathers are shed out ofphase with the rest of the plumage.

Cycle: In definitive (adult) birds, acycle is the time period that runsfrom a given plumage or molt to thenext occurrence of the sameplumage or molt. The number ofmolts and plumages equals the max­imum number of times any featherfollicle is normally activated. Thebasic plumage is commonly taken as

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the start of a plumage cycle. A cycleis a year in most temperate zonespecies, but shorter in some oceanicand tropical species. Cycles longerthan a year are few. A cycle oftenstraddles two calendar years. Mostbirds have either one basic plumageand one prebasic molt per year, ortwo plumages (basic and alternate)and two molts (prebasic and preal­ternate) per year. For example, aHorned Lark has only a basicplumage per year, and a ScarletTanager has two plumages, basicand alternate, per year.

Application: The Humphrey andParkes system also can be used withRoman numerals, but capitalize thenames of plumages and molts; forexample, Alternate II plumage,Prebasic I molt and so forth. Aswell, some terms can be abbreviat­ed but also must be capitalized; forexample, Def. Basic plumage, Def.Alt. plumage, Def. Suppl. plumage,All. I plumage and so forth. Theterms Basic and Prebasic are notabbreviated. Try not to mix termi­nologies, but adult alternateplumage, adult prebasic molt, adultin basic plumage and adult in preal­ternate molt and so forth are nowwidely used.

One or Two Molts?Most birds molt either once or twicea year. Knowing whether a birdmolts once a year or twice a year isthe key to determining its plumageand age. For example, adult birds

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that molt once a year have only onedefinitive (adult) plumage, called thedefinitive basic. Birds that molt twicea year have two definitive plumages:definitive basic (adult winter) anddefinitive alternate (adult breeding).Information below on the number ofmolts is based mainly on Oberholser(1974) and Pyle (1997).

One Molt: The following list appliesonly to those North American birdsfound north of Mexico. They haveone molt and therefore one plumageper year. After the juvenal plumage,they molt from basic to basic, repeat­ed as the only plumage. Any changesin appearance are caused by wear(loss of feather fringes) and fading insome species. In a few species, thechange in appearance between freshand worn plumage is striking, butthese are not separate plumages. Birdsthat have one molt are: albatrosses;shearwaters and petrels; storm­petrels; tropicbirds; boobies and gan­nets, except Northern Gannet;frigatebirds; New World vultures;whistling-ducks; geese and swans;ospreys; kites, eagles and hawks;caracaras and falcons; PlainChachalaca; partridges and pheas­ants; grouse, except ptarmigans;turkeys; jacanas; pigeons and doves;parrots; New World cuckoos; road­runners; anis; owls; goatsuckers;swifts; hummingbirds; trogons;Eurasian Hoopoe; kingfishers; wood­peckers; some tyrant flycatchers,induding Olive-sided Flycatcher,Greater Pewee, Western Wood-

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Pewee, Eastern Wood-Pewee, BlackPhoebe, Eastern Phoebe [see Pyle(1997) for exceptions]; some vireos,including White-eyed Vireo, Bell'sVireo, Hutton's Vireo, Red-eyedVireo, Yellow-green Vireo andBlack-whiskered Vireo; jays, Clark'sNutcracker, magpies, EurasianJackdaw, crows and ravens; larks;some swallows, including PurpleMartin and Cliff Swallow; chickadeesand titmice; verdins; bushtits; White­breasted Nuthatch; creepers; wrens,except Sedge Wren and MarshWren; dippers; kinglets; thrushes;Wrentit; catbirds, mockingbirds andthrashers; starlings; accentors;waxwings; Phainopepla; OliveWarbler; some wood-warblers,including Yellow-throated Warbler,Pine Warbler, Prothonotary Warbler,Worm-eating Warbler, Swainson'sWarbler, Hooded Warbler, Red­faced Warbler, Painted Redstart andYellow-breasted Chat [see Pyle(1997) for other species having anabsent to limited prealternate molt];bananaquits; some tanagers, includ­ing Hepatic Tanager and Flame-col­ored Tanager; some sparrows andbuntings (Emberizidae), indudingtowhees, Vesper Sparrow, Black­throated Sparrow, Sage Sparrow,Snow Bunting and McKay'sBunting; some cardinals and gros­beaks (Cardinalidae), indudingNorthern Cardinal, Pyrrhuloxia,Blue Grosbeak (has first prealter­nate molt only) and Varied Bunting;most blackbirds, except Bobolink,and some orioles (have mainly first

prealternate molt only); most finches,except goldfinches; and Old Worldsparrows. Note: Some birds listedabove may have alternate and/orsupplemental plumages that havenot been detected. See Pyle (1997)for more information and exceptionsto the above.

Two Molts: The following list appliesonly to those North American birdsfound north of Mexico. They havetwo molts and therefore twoplumages a year, both basic andalternate plumages. These birds are:loons; grebes; Northern Gannet; pel­icans; cormorants; darters; herons,bitterns and allies; ibises and spoon­bills; storks; flamingos; shelducks;true ducks (Anatinae); ptarmigans;New World quail; rails, gallinules andcoots; limpkins; cranes; lapwings andplovers; oystercatchers; stilts andavocets; sandpipers, phalaropes andallies; pratincoles; skuas, jaegers,gulls, terns and skimmers; auks, mur­res and puffins; Eurasian Wryneck;most tyrant flycatchers, including thegenus Empidonax [see Pyle (1997)for exceptions]; shrikes; some vire­os, including Black-capped Vireo,Yellow-throated Vireo and Warbling

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Vireo [see Pyle (1997) for details];swallows (probably very limited pre­alternate molt in most species);nuthatches, except White-breastedNuthatch; Sedge Wren and MarshWren; Old World warblers and gnat­catchers; Old World flycatchers;wagtails and pipits; most wood-war­blers [see Pyle (1997) for excep­tions]; some tanagers, includingSummer Tanager, Scarlet Tanagerand Western Tanager; most sparrowsand buntings (Emberizidae); mostCardinalidae, including Rose­breasted Grosbeak, Black-headedGrosbeak, Blue Grosbeak (firstprealternate molt only), LazuliBunting, Indigo Bunting, PaintedBunting and Dickcissel; some black­birds, including Bobolink, and ori­oles (mainly first prealternate molt);and a very few finches, includinggoldfinches. Omitted from the aboveare some passerines whose prealter­nate molt is so very limited (e.g., afew head feathers) that little or nodetectable change by molting occurs.Note: Some birds listed above mayhave a supplemental plumage thathas not been detected. See Pyle(1997) for more information andexceptions to the above.

Figures 3 and 4 are schematic colour illustrations by Peter Burke showingsequence of plumages in American Robin and Scarlet Tanager. Colour scheme:juvenal (gray), first basic (bronze), first alternate (orange), definitive basic (cin­namon), definitive alternate (purple). Corresponding plumages are the samecolours in both American Robin and Scarlet Tanager, but robin lacks an alter­nate plumage. Colours are not actual, but represent different feather genera­tions after each molt. Note retained feathers by the same colour as the previousplumage(s), usually wings and tail, following partial molts in first basic, firstalternate and definitive alternate plumages.

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Definitive Basic

(r

Figure 3: Male American Robin: example of species having one molt per year (cycle)after juvenal plumage. First basic acquired by partial molt; retained juvenalfeathers shown in gray. Definitive basic acquired by complete molt. Firstbasic and definitive basic plumages are very similar in robins, but carefulexamination will separate most birds. See Pyle (1997) for details.

See box on page 39 for colour scheme used in Figures 3 and 4.

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First Alternate

Definitive Basic

Definitive Alternate

Figure 4: Male Scarlet Tanager: example of species having two molts per year(cycle) after juvenal plumage. First basic acquired by partial molt; retainedjuvenal feathers shown in gray. First alternate acquired by partial molt;retained juvenal primaries/secondaries shown in gray. Definitive basicacquired by complete molt. Definitive alternate acquired by partial molt.See Pyle (1997) for details. For actual colours of the Scarlet Tanager, seePeter Burke's illustrations on page 393 in the new third edition of theNational Geographic Guide (1999). Juvenal plumage of Scarlet Tanager isnot illustrated in NGG.

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Table 1: Comparison of Plumage and Molt TerminologiesThe two charts below compare the names of plumages and molts in general usewith those of Humphrey and Parkes. Separate sequences are shown for birdsthat molt once a year and twice a year. The names of molts are in italics. Seepages 38 and 39 for number of molts.

(A) Plumage sequence for birds that molt once a year

General Humphrey and Parkesjuvenile plumage juvenal plumagePos(juvenile molt first prebasic moltfirst year plumage first basic plumage

adult postbreeding molt definitive prebasic moltadult plumage definitive basic plumage

(B) Plumage sequence for birds that molt twice a year

General Humphrey and Parkesjuvenile plumage juvenal plumagePos(juvenile molt first prebasic molt

first winter plumage first basic plumagefirst prebreeding molt first prealternate moltfirst summer plumage first alternate plumage

adult postbreeding molt definitive prebasic moltadult winter plumage definitive basic plumage

adult prebreeding molt definitive prealternate moltadult breeding plumage definitive alternate plumage

Most birds, whether they molt once or twice per cycle (year), acquire theirfirst definitive basic plumage in late summer or early fall of their second cal­endar year, when they are just over a year old. For most species that molttwice per cycle, they acquire their first definitive alternate plumage in latewinter or spring of their third calendar year, somewhat before two years ofage. Definitive plumages are repeated for the life of the bird. Additionalmolts and plumages can be added for species that take longer to reachdefinitive plumage. Presupplemental molts and supplemental plumages alsocan be inserted into the above sequences.

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Recommendations1. In your field guide, write the number 1 or 2 beside the birds that haveeither one or two molts per year. This is the key to knowing if a bird has onlya basic plumage or both basic and alternate plumages.

2. Label the birds in your field guide, using the Humphrey and Parkes ter­minology

3. Practice looking closely at photographs of birds in books. Try ageing andassigning plumages and molts by looking for different feather generations,and signs of molt and wear.

4. Check out the selected references below. If you want to know more, requestthe cited papers and books from a library.

5. Get out in the field and study the common birds more closely. It takes work,but you will soon expand your knowledge and understanding.

6. Finally, I am always happy to discuss birds and answer questions. You maysee me in the field or write to the address below or telephone in the earlyevening at (705) 286-3471.

AcknowledgementsI thank Peter Burke, Earl Godfrey,Michel Gosselin, Jean Iron, AlvaroJaramillo, Michael King, KevinMcLaughlin and Ron Tozer for theirvaluable assistance. Peter Burkekindly prepared the illustrations.

Selected ReferencesHumphrey, P.S. and K.C. Parkes. 1959. An

approach to the study of molts andplumages. Auk 76: 1-31. It is highly recom­mended for the advanced birder, butrequires several readings.

Oberholser, H.C. 1974. The Bird Life ofTexas. Volumes 1 and 2. University ofTexas Press, Austin, Texas. It providesextremely detailed plumage descriptions,is like having the bird in the hand, and ishighly recommended.

Palmer, R.S. 1962, 1976, 1988. Handbook ofNorth American Birds. Volumes 1 to 5:Loons through Diurnal Raptors. YaleUniversity Press, New Haven,Connecticut. These volumes contain someof the best information available on NorthAmerican birds.

Pyle, P. 1997. Identification Guide to NorthAmerican Birds. Part 1. Slate Creek Press,Bolinas, California. The most authorita­tive guide to plumages, molts, ageing andsexing birds in the hand and in the field.Pyle uses an interesting and effectivecombination of banding codes and tradi­tional terms, mixed with terminology ofHumphrey and Parkes (1959).

Wilds, C. 1989. The terminology of plumageand molt. Birding 21: 148-154. This is oneof the best articles written for birders onusing plumage and molt terminologies. Itstrongly endorses the Humphrey andParkes terminology.

Ron Pittaway, Box 619, Minden, Ontario KOM 2KO

VOLUME 18 NUMBER 1