Plumages, Molts, and Structure

The Great Tit has 10 primaries (numbered distally, from innermost p1 to outermost p10, the outermost reduced in length), 9 secondaries (numbered proximally from outermost s1 to innermost s9 and including 3 tertials, s7–s9 in passerines), and 12 rectrices (numbered distally, from innermost r1 to outermost r6 on each side of the tail). Geographic variation in appearance is extensive and variable, with some 15 subspecies recognized here, and more described. The following general descriptions are based primarily on plumage descriptions of European subspecies (in particular, P. m. major and newtoni) from Cramp and Perrins (2 Cramp, S. and C. M. Perrins. (1993b). The birds of the Western Palearctic, Vol. 7: flycatchers to shrikes. Oxford, U.K: Oxford Univ. Press. Close ), Harrap and Quinn (3 Harrap, S., and D. Quinn (1995). Chickadees, Tits, Nuthatches and Treecreepers. Princeton University Press, Princeton, NJ, USA. Close ), and Shirihai and Svensson (4 Shirihai, H., and L. Svensson (2018). Handbook of Western Palearctic Birds. Volume 1. Passerines: Larks to Warblers. Bloomsbury, London, UK. Close ), along with examination of Macaulay Library images. See Systematics: Geographic Variation for geographic variation in plumage appearance, and the above resources and Svensson (5 Svensson, L. (1992). Identification Guide to European Passerines. Fourth edition. Published privately, Stockholm, Sweden. Close ), Jenni and Winkler (6 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ), and Ottenby Bird Observatory (7 Ottenby Bird Observatory (2023). Ringers' Digiguide. https://ringersdigiguide.ottenby.se/ Close ) for illustrated ageing and sexing criteria. See Molts for information on Humphrey-Parkes molt and plumage terminology (8 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. Auk 76(1):1–31. Close ), used by Birds of the World. Appearance of sexes is rather similar in Juvenile Plumage but differs slightly in subsequent plumages. Definitive appearance is assumed at the Second Basic Plumage.

Natal Down

Present primarily May–July, in the nest. Naked at hatching (cf. ML152036411 ) but quickly grows sparse natal down described as gray at first, then white, and restricted to the crown, back, scapulars and alar tracts (2 Cramp, S. and C. M. Perrins. (1993b). The birds of the Western Palearctic, Vol. 7: flycatchers to shrikes. Oxford, U.K: Oxford Univ. Press. Close ).

Juvenile (First Basic) Plumage

Present primarily June–August, on or near the natal territory. Juveniles are similar to definitive basic females, but crown to nape browner or brownish olive; nuchal spot small and dingy; upperparts duller olive green and grayer on rump and uppertail coverts; tail duller and grayer with poorly defined whitish tips on the outer two rectrices (r5–r6); upperwing secondary coverts weak and sometimes washed or fringed olive; upper breast with smaller dark gray bib and narrower dark gray ventral line; remainder of underparts paler yellow with more grayish wash on flanks. Juvenile primaries and rectrices are thinner and more tapered or pointed at the tips than basic feathers, and juvenile body feathers are weaker and more filamentous (barb density sparser) than those of later plumages, especially along the sides of the underparts and the undertail coverts. In addition, the bill of juveniles often shows yellow coloration along the cutting edged of the mandibles (see Bare Parts).

In Poland (subspecies P. major major), an analysis of carotenoid chroma levels indicated that the plumage of juveniles raised in nest boxes was brighter than those raised in natural cavities, potentially due to better nutritional condition of nest-box-raised broods (9 Janas, K., I. Di Lecce, M. Szulkin, and J. Sudyka (2024). Plumage coloration differs between offspring raised in natural cavities and nestboxes. Ornithology 2024, ukae002. Close ). It is possible that duller juvenile females may be reliably distinguished from brighter juvenile males, as found in the similar Green-backed Tit (Parus monticolus), but with substantial overlap also likely occurring; study is needed.

Formative Plumage

Termed "post-juvenile" or "first adult" plumage under life-cycle terminology. Present primarily September (when fresh) to July (when worn). Body feathering similar in appearance to Definitive Basic Plumage. Best separated by molt limits among inner secondaries, between upperwing greater and primary coverts, and among alula, which are quite variable in position by sex, by population, and interannually (6 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ; see Molts). In all cases, molt limits occur among the tertials and inner secondaries, 2–5 feathers replaced, fresh, black, and with broader white fringing, contrasting with more worn, duller, and browner, adjacent unreplaced secondaries (beware basic tertials and sometimes additional proximal secondaries are naturally blacker than adjacent inner secondaries, creating a "pseudolimit"). Primary coverts are washed brown, have reduced or no bluish edging, and contrast in quality with replaced formative greater coverts (occasionally 1–3 juvenile outer greater coverts are retained and contrast noticeably with replaced inner feathers). Limits often occur among the alula, the alula covert always replaced and fresher, the lesser alula replaced or not, and the greater alula often retained, brown, and contrasting with the replaced lesser alula (cf. ML608472270 ). Retained juvenile outer primaries are narrow, tapered at the tips, and relatively worn and brownish. Rectrices are usually replaced and match those of basic feathers but occasionally one or more juvenile outer feathers may be retained and are contrastingly weak, brownish, and abraded. By spring, molt limits can become more pronounced due to more extensive deterioration of juvenile relative to that of formative feathers (cf. ML190877381 ).

Formative body feathering and upperwing coverts of females and males differ in similar ways to those of Definitive Basic plumage, although body feathering is duller within each sex. In some cases formative males may match definitive basic females in plumage brightness and distribution of white in the cheeks and black to the underparts, so it can be best to determine age (among the given subspecies) before sexing birds of intermediate brightness. Formative females are often diagnostically duller than other age/sex groups.

Definitive Basic Plumage

Termed "adult" plumage under life-cycle terminology. Present primarily September (when fresh) to July (when worn).

Female. Forehead to crown (to below eye) and nape dull black with dull whitish patch on center of lower nape, becoming dullish greenish yellow on lowermost hindneck and upper mantle; rest of mantle, scapulars, and upper back dullish green, the scapulars tinged olive; lower back to uppertail coverts light bluish gray, tinged green on rump. Longest uppertail coverts and tail bluish gray with blackish inner webs, the outer three rectrices (r4–r6) tipped white, often minutely so on r4, but with white extending as a wedge to about half feather length on inner web and over entire outer web of the outermost rectrix (r6). Sides of head with distinct, moderately sized, wedge-shaped white patch extending from the lores and below the eye to the sides of the nape and through the auriculars, bordered below by a broad black stripe. Upperwing lesser and median coverts grayish blue; greater coverts with blackish on inner webs, fringed greenish gray on outer webs and broadly tipped white; alula and primary coverts blackish, finely fringed white or pale grayish blue; flight feathers blackish gray, the tertials blacker and broadly fringed pale greenish yellow (becoming white towards tip) and the secondaries and inner primaries finely fringed pale grayish blue. Chin, throat and sides of neck to center of upper breast blackish to black forming a bib; a narrow and irregular black line extends from the lower bib to the vent (may be broken or show white tips towards vent); sides of breast and belly dull yellow to greenish, the flanks washed grayish to greenish gray; undertail coverts white with tips of longest blackish; axillars and underwing coverts whitish ( ). In worn plumage, crown and nape duller, less glossy, upperparts duller green, ventral line slightly broader, and rest of underparts paler yellow, or grayer on flanks.

In both sexes, Definitive Basic Plumage separated from Formative Plumage by having upperwing coverts and inner secondaries uniform in wear and quality, without molt limits; basic outer primaries broad, more truncate (less pointed), and relatively fresh. Subtle "molt clines" are often observable among the remiges reflecting replacement sequences (cf. 10 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, California, USA. Close ), from slightly more worn p1 to darker and fresher p9 , and medium fresh s1 (contrasting with more-worn p1) to darker and fresher s6, which sometimes contrasts with slightly more worn s7. Clines among the secondaries are often more observable, especially in February–July, by which time the cline among the primaries is counterbalanced by increased exposure distally.

Male. Like definitive basic female but brighter overall; crown and nape glossy bluish black; upperparts brighter green; fringes of greater coverts and secondaries greenish gray (not grayish blue); inner webs to remiges blacker. Underparts with bib glossier and blacker, ventral line broader and blacker, sides and flanks brighter yellow, and undertail coverts more extensively black.

General

Molt and plumage terminology follows Humphrey and Parkes (11 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. The Auk 76:1–31. Close ) as modified by Howell et al. (12 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: A review of molt and plumage homologies. The Condor 105:635–653. Close ). Under this nomenclature, terminology is based on evolution of molts along ancestral lineages of birds from ecdysis (molts) of reptiles (cf. 13 Pyle, P., S. N. G. Howell, D. I. Rogers, and C. Corben (2024). Moult terminology: envisioning an evolutionary approach. Journal of Avian Biology 2024:e03169. Close ), rather than on molts relative to breeding season, location, or time of the year, the latter generally referred to as “life-cycle” molt terminology (6 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ). In north-temperate latitudes and among passerines, the Humphrey-Parkes (H-P) and life-cycle nomenclatures correspond to some extent but terms are not synonyms due to the differing bases of definition. Prebasic molts often correspond to “post-breeding“ or “post-nuptial“ molts, preformative molts often correspond to “post-juvenile“ molts, and prealternate molts often correspond with “pre-breeding“ molts of life-cycle terminology. However, for species that suspend prebasic or preformative molts for migration or undergo extensive molts on winter grounds, there is often a lack of correspondence between H-P and life-cycle terms (14 Pyle, P. (2022). Defining moults in migratory birds: A sequence-based approach. Journal of Avian Biology 2022:e02958. Close ). The terms prejuvenile molt and juvenile plumage are preserved under H-P terminology (considered synonyms of first prebasic molt and first basic plumage, respectively) and the former terms do correspond with those in life-cycle terminology. The Great Tit undergoes a Complex Basic Strategy (cf. 12 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: A review of molt and plumage homologies. The Condor 105:635–653. Close , 15 Howell, S. N. G. (2010). Peterson Reference Guide to Molt in North American Birds. Houghton Mifflin Harcourt, Boston, MA, USA. Close ), including complete prebasic molts and a partial preformative molt but no prealternate molts (16 Dement'ev, G. P., and N. A. Gladkov (1954). Birds of the Soviet Union. Volume 6. Moscow. [English translation in 1968 by the Israel Program for Scientific Translations, Jerusalem, and Smithsonian Institution and National Science Foundation, Washington, DC, USA]. Close , 17 Ginn, H. B., and D. S. Melville (1983). Moult in Birds. British Trust for Ornithology Guide 19. British Trust for Ornithology, Tring, UK. Close , 2 Cramp, S. and C. M. Perrins. (1993b). The birds of the Western Palearctic, Vol. 7: flycatchers to shrikes. Oxford, U.K: Oxford Univ. Press. Close , 4 Shirihai, H., and L. Svensson (2018). Handbook of Western Palearctic Birds. Volume 1. Passerines: Larks to Warblers. Bloomsbury, London, UK. Close , 6 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ).

Prejuvenile (First Prebasic) Molt

Complete, in the nest cavity, primarily during May‒July. Little published on this molt due to presence in nest cavities. As in most passerines, juvenile feathering presumably develops ca. 4–7 days post hatch and is completed or near-completed at fledging at 16–22 days, although outer primaries and (especially) rectrices of fledged juveniles can still be as little as half grown. The Prejuvenile Molt may take longer in the Great Tit than in other passerines due to the protection afforded by nest cavities.

Preformative Molt

Partial, primarily in July‒September, mostly or entirely on summer grounds, prior to autumn migration or dispersal. Includes all body feathers and upperwing lesser and median coverts, usually all greater coverts (up to three outer feathers occasionally retained), and 2–6 inner tertials and secondaries among s4–s9 (2 Cramp, S. and C. M. Perrins. (1993b). The birds of the Western Palearctic, Vol. 7: flycatchers to shrikes. Oxford, U.K: Oxford Univ. Press. Close , 6 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close , 7 Ottenby Bird Observatory (2023). Ringers' Digiguide. https://ringersdigiguide.ottenby.se/ Close ; Macaulay images e.g., ML149155021 ). Somewhat unusual for a passerine, rectrices are usually entirely replaced during the Preformative Molt, although occasionally 1–2 outer feathers can be retained, perhaps in late-fledging individuals with time constraints on molt; such birds may also be expected to retain some outer greater coverts and replace as few as 1–2 tertials. First-year birds of northern populations average fewer feathers replaced than those of southern populations (2 Cramp, S. and C. M. Perrins. (1993b). The birds of the Western Palearctic, Vol. 7: flycatchers to shrikes. Oxford, U.K: Oxford Univ. Press. Close , 6 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ).

Definitive Prebasic Molt

Complete, primarily late-June to early October, with average duration at the individual level 70–90 days (17 Ginn, H. B., and D. S. Melville (1983). Moult in Birds. British Trust for Ornithology Guide 19. British Trust for Ornithology, Tring, UK. Close ; see 2 Cramp, S. and C. M. Perrins. (1993b). The birds of the Western Palearctic, Vol. 7: flycatchers to shrikes. Oxford, U.K: Oxford Univ. Press. Close for details). Completes on summer grounds, usually before autumn migration, although relationship between breeding territories and molting grounds (cf. 18 Pyle, P., J. F. Saracco, and D. F. DeSante (2018). Evidence of widespread movements from breeding to molting grounds by North American landbirds. The Auk: Ornithological Advances 135:506–520. Close ) may require further study. Few Macaulay Library images are of birds molting primaries, indicating that they are retiring at this time, as is common among passerines. Primaries (and corresponding primary coverts) are replaced distally (p1 to p10), secondaries are replaced proximally from s1 and proximally and distally from the central tertial (s8), and rectrices are generally replaced distally (r1 to r6) on each side of the tail, though variation in sequence of rectrix molt may occur. Post-breeding males sometimes commence prebasic molt before females, and southern populations commence feather replacement earlier than northern ones.

The following is based on descriptions in Harrap and Quinn (1 Harrap, S., and D. Quinn (1996). Tits, Nuthatches and Treecreepers. Christopher Helm, London, UK. Close ) along with examination of Macaulay Library images. See also images under Plumages.

Bill and Gape

In adults, black, with paler cutting edges when opened, and sometimes a very small pale tip to the culmen. In nestlings (cf. ML593947021 ) the bill is grayish with an extensively yellow base, and the swollen gape is also pale to bright yellow. The the bill of juveniles often continues to show yellow coloration along the cutting edged of the mandibles (cf. images under Juvenile Plumage), and the inside of the mouth can continue to be bright yellow.

Iris

In adults, dark reddish brown to blackish brown. The iris of juveniles may average paler or grayer than in adults.

Tarsi and Toes

In adults, the legs and feet are slate gray to blue gray. In nestlings they are pinkish and in juveniles they can be gray tinged pink.

Data from Cramp and Perrins (19 Cramp, S., and C. M. Perrins, Editors (1993). The Birds of the Western Palearctic. Volume 7. Flycatchers to shrikes. Oxford University Press, Oxford, UK. Close ).

Linear Measurements

Overall length 22.5–25.5 cm.

Wing Length

• P. m. major males 74–82 cm, n = 45 (mean 77.6 cm); females 73–77 cm, n = 13 (mean 75 cm).
• P. m. newtoni males 73–78 cm, n = 17 (mean 76.2 cm); females 70–76 cm, n = 12 (mean 73.8 cm).
• P. m. corsus males 70–78 cm, n = 27 (mean 74.1 cm); females 69–74 cm, n = 8 (mean 71.3 cm).
• P. m. ecki males 70–78 cm, n = 39 (mean 73.7 cm); females 69–75 cm, n = 14 (mean 71.2 cm).
• P. m. mallorcae males 70–75 cm, n = 16 (mean 72.2 cm); females 69–74 cm, n = 12 (mean 70.8 cm).
• P. m. excelsus males 74–84 cm, n = 62 (mean 77.0 cm); females 72–77 cm, n = 22 (mean 74.2 cm).
• P. m. aphrodite males 72–77 cm, n = 17 (mean 74.2 cm); females 69–72 cm, n = 10 (mean 71.1 cm).
• P. m. niethammeri males 68–73 cm, n = 18 (mean 70.6 cm); females 67–71 cm, n = 13 (mean 67.9 cm).
• P. m. terraesanctae males 69–76 cm, n = 1 0 (mean 71.8 cm); females 67‒70 cm, n = 2.
• P. m. blanfordi males 73–81 cm, n = 77 (mean 76.3 cm).

Tail Length

• P. m. major males 58–66 cm, n = 58 (mean 62.7); females 55–63 cm, n = 54 (mean 58.4 cm).
• P. m. newtoni males 58–65 cm, n = 13 (mean 61.7 cm); females 55–61 cm, n = 12 (mean 73.8 cm).
• P. m. corsus males 58–64 cm, n = 15 (mean 60.5 cm); females 56–61 cm, n = 5 (mean 58.2 cm).
• P. m. ecki males 59–65 cm, n = 8 (mean 62.3); females 58–62 cm, n = 4 (mean 59.5 cm).
• P. m. excelsus males 59–68 cm, n = 9 (mean 62.8 cm); females 56–66 cm, n = 10 (mean 60 cm).
• P. m. aphrodite males 58–65 cm, n = 7; (mean 61.6 cm); females 57–60 cm, n = 3 (mean 58.7 cm).
• P. m. blanfordi males 57–69 cm, n = 73 (mean 64.2 cm).

Bill Length

• P. m. major males 12.0–13.2 cm, n = 13 (mean 12.7 cm); females 11.8–13.1 cm, n = 12 (mean 12.5 cm).
• P. m. newtoni males 12.4–14.0 cm, n = 17 (mean 13.1 cm); females 9.1–10.3 cm, n = 10 (mean 9.6 cm).
• P. m. corsus males 11.9–13.2 cm, n = 14 (mean 12.6 cm); females 11.7–12.9 cm, n = 6 (mean 12.4 cm).
• P. m. ecki males 12.0–13.3 cm. n = 8 (mean 12.7 cm); females 11.6–13.5 cm, n = 4 (mean 9 cm).
• P. m. excelsus males 12.9–14.5 cm, n = 39 (mean 13.6 cm); females 12.8–13.9 cm, n = 9 (mean 13.2 cm).
• P. m. aphrodite males 12.2–14.0 cm, n = 22 (mean 13 cm); females 11.9–13.1 cm, n = 4 (mean 12.4 cm).
• P. m. terraesanctae males 12.0–13.5 cm, n = 7 (mean 12.9 cm).
• P. m. blanfordi males 12.5–14.0 cm, n = 76 (mean 13.4 cm).

Tarsus Length

• P. m. major males 19.8–21.7 cm, n = 54 (mean 20.8 cm); females 18.7–20.9 cm, n = 53 (mean 19.8 cm).
• P. m. newtoni males 20.2–22.1 cm, n = 14 (mean 21.2 cm); females 19.4–21.6 cm, n = 12 (mean 20.6 cm).
• P. m. corsus males 19.0–20.8 cm, n = 15 (mean 20 cm); females 18.4–20.9 cm, n = 5 (mean 19.6 cm).
• P. m. ecki males 20.2–21.8 cm, n = 8 (mean 20.9 cm); females 19.4–20.5 cm, n = 4 (mean 19.8 cm).
• P. m. excelsus males 20.5–22.2, n = 9 (mean 21.3); females 19.8–22.2 cm, n = 9 (mean 20.7 cm).
• P. m. aphrodite males 19.3–21.3 cm, n =7 (mean 20.1 cm); females 19.6–20.3 cm, n = 4 (mean 19.8 cm).

Mass

• P. m. major males 16.3–22.1 g, n = 145 (mean 19.1 g); females 15.0–21.1 g, n = 139 (mean 17.9 g).
• P. m. newtoni males 16.8–22.1 g, n = 94 (mean 19.2 g).
• P. m. aphrodite males 12.9–23.0 g, n = 61 (mean 16.5 g)
• P. m. karelini males 19–20 g, n = 5 (mean 19.4 g); female 20 g.
• P. m. blanfordi males 16.2–18.5 g, n = 9 (mean 17.4 g); females 15.1‒15.7 g, n = 2.