Plumages, Molts, and Structure

The Eurasian Hoopoe has ten full-length primaries (numbered distally, from innermost p1 to outermost p10, the p10 reduced in length and narrow), 11 secondaries (numbered proximally, from outermost s1 to innermost s8, and including three tertials, numbered distally, t1 to t3), and 10 rectrices (numbered distally on each side of the tail, from innermost r1 to outermost r5). The wing is rounded, with p7 the longest, p10 shorter by 60–70 mm, and p1 shorter by 28–36 mm; p6‒p9 are notched on the inner web, and p5‒p8 are emarginated on the outer web (1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ). Geographic variation in appearance is slight to moderate (see Systematics: Geographic Variation). The following molt and plumage descriptions cover all subspecies and are based on those of Glutz von Blotzheim and Bauer (5 Glutz von Blotzheim, U. N., and K. M. Bauer (1980). Handbuch der Vögel Mitteleuropas. Band 9 Columbiformes-Piciformes. Akademische Verlagsgesellschaft, Wiesbaden, Germany. Close ), Cramp (1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ), Maclean (6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close ), Wells (7 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close ), and Kristin (8 Kristin, A. (2001). Family Upupidae (Hoopoes). In Handbook of the Birds of the World, Volume 6 (J. del Hoyo, A. Elliott, and J. Sargatalm, Editors), Lynx Edicions, Barcelona, Spain. pp. 396–411. Close ), along with an examination of Macaulay Library images; see Baker (9 Baker, J. K. (2016). Identification Guide to European Non-Passerines. British Trust for Ornithology, Thetford, Norfolk. Close ) and Blacso-Zumeta and Heinze (10 Blasco-Zumeta, J., and G.-M. Heinze (2022). Atlas de Identificación de las Aves Continentales de la Península Ibérica. Tundra Ediciones, Zaragoza, Spain. Close , 11 Blasco-Zumeta, J., and G.-M. Heinze (2022). Identification Guide of Birds of Aragón and Continental Spain. Aranzadi Sciences Society, Donostia-San Sebastián, Spain. Close ) for information on aging and sexing. See Molts for information on Humphrey-Parkes molt and plumage terminology used by Birds of the World. Sexes are rather similar in all plumages although show slight average differences within plumages and populations (see below); definitive appearance is attained at the Second Basic Plumage. Timing of plumages (e.g., fresh versus worn) listed below based on peak times of breeding and molt for most subspecies (see Molts); those of southern Africa (including Upupa epops africana) appear to occur 2–4 months later in timing (see Molts).

Natal Down

Present in the natal cavity, primarily in March–July in most populations (see above). Natal down white, long, and filamentous on crown and upper back, sparser on lower back and underparts (1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ).

Juvenile (First Basic) Plumage

Present primarily in May–October in most populations (see above). Similar to Definitive Basic Plumage (including crest feathers) but averages duller and usually somewhat paler. Juvenile body feathers are more filamentous than those of later plumages due to lower barb densities. Juvenile outer primaries and rectrices are narrower and more pointed or tapered at their tips than basic feathers and are fresh when adults of the same population are worn, the rectrices are tipped buff when fresh. A swollen pale yellow gape from the nestling period often remains visible in juveniles, and the bill is shorter than in adults (see Bare Parts). Sexes appear to be similar in Juvenile Plumage.

Formative Plumage

Present primarily in November (when fresh) to March or September (when worn) in most populations (see above); depends on if First Prealternate Molts occur (see below). Note birds in transitional states of molt may occur in August–January, including during migration in northern-breeding populations (see Molts). Similar to Definitive Basic Plumage but body feathering averages slightly duller and paler within each sex. Best identified by molt limits among wing and tail feathers and condition and quality of retained juvenile flight feathers. One to three tertials are often (but not always) replaced, contrastingly black, and with buff bars when fresh. Retained juvenile outer primaries and rectrices are narrower than basic feathers, tapered or rounded and brownish at the tips, and relatively worn; one or more pairs of central rectrices sometimes replaced and contrastingly black and truncate (all rectrices replaced in some birds). It may be possible that juvenile secondaries average smaller white subterminal spots within each sex than basic secondaries (see images in 11 Blasco-Zumeta, J., and G.-M. Heinze (2022). Identification Guide of Birds of Aragón and Continental Spain. Aranzadi Sciences Society, Donostia-San Sebastián, Spain. Close ), but study on this throughout the range of the Eurasian Hoopoe is needed. Replacement extent of upperwing secondary coverts during the Preformative Molt is poorly known but examination of Macaulay Library images suggests that some birds may only partially replace these coverts, with at least some outer median and/or greater coverts, along with the primary coverts, retained, worn, and brownish and dull whitish, contrasting with fresher and bolder black (with buff bars when fresh) replaced inner secondary coverts (see image below). Confirmation of this is needed, however. Sexes appear to be similar in Formative Plumage but slight average differences, as described below, may occur.

First and Definitive Alternate Plumages

These plumages have been suspected to occur in the Eurasian Hoopoe (1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close , 9 Baker, J. K. (2016). Identification Guide to European Non-Passerines. British Trust for Ornithology, Thetford, Norfolk. Close , 11 Blasco-Zumeta, J., and G.-M. Heinze (2022). Identification Guide of Birds of Aragón and Continental Spain. Aranzadi Sciences Society, Donostia-San Sebastián, Spain. Close ), but confirmation is needed. If they exist, they occur primarily in February–June and resemble Formative and Definitive Basic Plumages, respectively, but show patchy newer alternate feathers to the head, nape, sides of the neck, and upper back (see images below). These plumages may occur more regularly in migratory, northern-breeding populations than in resident, southern-breeding populations. Contrasting new and old head and neck feathers could also result from other factors, e.g., related to protracted molts or variable intrinsic quality of these feathers; study is needed. Criteria to separate First from Definitive Alternate Plumage as described under Formative Plumage, but retained juvenile feathers are more worn and molt limits often more evident. If these plumages exist, sexes should differ as described below, at least in Definitive Alternate Plumage.

Definitive Basic Plumage

Present primarily in November (when fresh) to march or September (when worn) in most populations (see above), depending on whether or not Definitive Prealternate Molts occur; note birds in transitional states of molt may occur in August–November, including during migration in northern-breeding populations (see Molts). Crown with prominent ornamental feathers, extending back beyond nape when flat and into a prominent fan-like crest when extended; these are rufous-orange with black tips, the longer feathers often with a paler (to whitish) subterminal band proximal to the tip. Remainder of head, nape, upper back feathers, and marginal upperwing lesser coverts are variably buff-orange, cinnamon, and/or grayish tan, often patchy in appearance. Mantle, scapulars, most upperwing secondary coverts, tertials, and secondaries black with buff or orange-buff (when fresh) to white bands and narrow white tips on some feathers, creating a boldly black-and-white barred pattern, especially in flight. Tertials black with broad white, buff, or buff-orange fringes. Primary coverts and alula black; primaries black with a white subterminal band narrower and more distal on p1, gradually widening and located farther from the tip by p9; p10 narrow and black with a white spot. Lower back, rump, and uppertail coverts primarily white with black band across the rump. Rectrices black with a white band, narrow and more basal on the central rectrices, widening laterally, and extending farther toward the tip by the outer web of r5. Underparts primarily tan to vinaceous pink, slightly paler on throat and paling to whitish on the flanks then to white in the ventral region and undertail coverts; dark brown streaks are often present on the lower flanks and sometimes the abdomen. Underwing coverts variably pinkish to tan and whitish, usually becoming whiter distally and on the primary coverts (cf. ML617222562, ML553957971, ML328037391, ML582121531, ML354607161).

Definitive Basic Plumage is separated from Formative Plumage by showing uniformly basic upperwing coverts and flight feathers, without retained juvenile feathers (see Formative Plumage, above). Basic remiges and rectrices are jet black when fresh (with buff or white bands), becoming blackish with slightly brownish tips when worn, the outer primaries and rectrices broader and more truncate than retained juvenile feathers of Formative Plumage.

In Definitive Basic Plumage, sexes show slight differences, with Females averaging duller crest feathers, heads, and breasts, tending toward tan or dull cinnamon, and Males having brighter crests, more saturated cinnamon to orangish head feathers and deeper pinkish or vinaceous breasts. Extremes appear to be reliably sexed, especially when in mated pairs, but age, plumage wear, and geographic variation all have to be considered; most single birds are likely not reliably sexed.

Aberrant Plumages

Albinism has been reported in India (12 Brooke, A. T. (1911). An albino Hoopoe Upupa indica. Journal of the Bombay Natural History Society 20(3):853–854. Close , 13 Rudkin, H. K. (1925). An albino Hoopoe (Epopa epops indica). Journal of the Bombay Natural History Society 30(4):916. Close ).

Molt and plumage terminology follows Humphrey and Parkes (14 Humphrey, P. S., and K. C. Parkes (1959). An approach to the study of molts and plumages. Auk 76(1):1–31. Close ) as modified by Howell et al. (15 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. 16 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 current breeding seasons, locations, or time of year, the latter generally referred to as “life-cycle” molt terminology (17 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close ). Prebasic molts often correspond to “post-breeding“ or “post-nuptial“ molts, prealternate molts often correspond to “pre-breeding“ molts, and preformative molts often correspond to “post-juvenile“ molts; however, there is a lack of equivalency due to different bases of definition (18 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 Humphrey-Parkes 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 Eurasian Hoopoe may exhibit a Complex Basic Strategy or a Complex Alternate Strategy (cf. 15 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 , 19 Howell, S. N. G. (2010). Molt in North American Birds. Houghton Mifflin Harcourt, Boston, Massachusetts and New York, New York, USA. Close ), including complete prebasic molts, a partial to incomplete preformative molt, and possibly limited prealternate molts in both first and definitive cycles (see below). The following is based primarily on information in Stresemann and Stresemann (20 Stresemann, E., and V. Stresemann (1966). Die Mauser der Vögel. Journal für Ornithologie 107(Supplement):1–439. Close ), Cramp (1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ), Wells (7 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close ), Baker (9 Baker, J. K. (2016). Identification Guide to European Non-Passerines. British Trust for Ornithology, Thetford, Norfolk. Close ), and Blacso-Zumeta and Heinze (10 Blasco-Zumeta, J., and G.-M. Heinze (2022). Atlas de Identificación de las Aves Continentales de la Península Ibérica. Tundra Ediciones, Zaragoza, Spain. Close , 11 Blasco-Zumeta, J., and G.-M. Heinze (2022). Identification Guide of Birds of Aragón and Continental Spain. Aranzadi Sciences Society, Donostia-San Sebastián, Spain. Close ), as augmented by examination of Macaulay Library images. Timing of molts (given below) follows that of breeding, which occurs primarily in March–July in most populations but peaks in August–November in some populations of southern Africa (Upupa epops africana; see Breeding: Phenology). Molt can be suspended and protracted in migratory northern-breeding populations but may occur more rapidly in resident populations.

Prejuvenile (First Prebasic) Molt

Complete, primarily March–June in most populations (see above). At the end of week 1 after hatching, closed feather sheaths appear and cover body by week 2, creating spiny appearance with down still present on tips; feathers erupt during days 15–18 after hatching, and nestlings appear fully feathered by days 22–23 (21 Skead, C. J. (1950). A study of the African Hoopoe. Ibis 92:434–463. Close , 1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ). Final growth of primaries and rectrices likely occurs following fledging at days 26–32 after hatching.

Preformative Molt

Often termed “post-juvenile molt“ under life-cycle terminology. Partial to incomplete, occurring primarily August–January in most populations (see above). In migratory northern-breeding populations, can commence with a few body feathers on or near breeding grounds (prior to southbound migration) but molt takes place largely on nonbreeding grounds. It includes most to all body feathers, often (but not always) 1–3 tertials, and sometimes 1–2 central rectrices (r1; occasionally additional central rectrices and rarely all rectrices), but no primary coverts, primaries, or other secondaries or rectrices. If molt of the largest tertial or central rectrices occurs, it appears to be last, as late as January or later. Extent of secondary covert replacement poorly known. Study of Macaulay Library images suggests that most or all coverts may usually be replaced (as generally expected in birds when tertials are replaced) but that some outer juvenile median and greater coverts may be retained in some birds, especially those that lack replacement of any tertials or rectrices. More study is needed.

First and Definitive Prealternate Molts

Often considered "first pre-breeding" and "adult pre-breeding" molts, respectively, under life-cycle terminology. Limited Prealternate Molts on nonbreeding grounds have been postulated to occur but confirmation is needed. Timing has been speculated as January–February, but molt extending into March or later may be expected as well. If present, prealternate molts may occur more regularly in migratory populations, as occurs in passerines (17 Jenni, L., and R. Winkler (2020). Moult and Ageing of European Passerines. Second edition. Bloomsbury, London, UK. Close , 22 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, California, USA. Close ). Some individuals of both first-cycle and older birds of these populations appear to show scattered new feathers in at least the head, nape, sides of neck, and upper breast (see images under First and Definitive Alternate Plumages) while others appear to lack new feathers. Variation in feather wear may be caused by other factors such as protracted timing of replacement during Preformative and Definitive Prebasic Molts, or to intrinsic feather quality. Study is needed to confirm whether or not individual follicles can be activated twice within a molt cycle, signifying prealternate molts.

Second and Definitive Prebasic Molts

Often considered “first post-breeding“ and “adult post-breeding" molts, respectively, under life-cycle terminology. Complete, primarily in August‒February in most populations (see above), with flight-feather molt perhaps occurring most frequently in November–February on nonbreeding grounds. Primaries and corresponding primary coverts are replaced distally (p1 to p10), secondaries are replaced bidirectionally from the middle tertial (t2) and proximally from the outermost secondary, with s4 typically the last secondary replaced. Molt of rectrices commences with r1 and may occur irregularly thereafter, with r5 being replaced before r3–r4 (see images below).

Images of birds undergoing active primary molt are rare, indicating they are retiring at this time, and that molt may occur at secluded locations. In northern migratory populations, molt can commence on or near breeding grounds in some birds, perhaps more often in nonbreeding birds or failed breeders, including those undergoing Second Prebasic Molt. Body feathers around the head and sometimes inner primaries, tertials, and inner rectrices can be replaced before suspension for migration.

The following is based on descriptions in the literature (1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close , 6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close , 7 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close , 8 Kristin, A. (2001). Family Upupidae (Hoopoes). In Handbook of the Birds of the World, Volume 6 (J. del Hoyo, A. Elliott, and J. Sargatalm, Editors), Lynx Edicions, Barcelona, Spain. pp. 396–411. Close ), along with an examination of Macaulay Library images.

Bill and Gape

In adults, the bill is long and evenly decurved. It is blackish or blackish-brown distally grading to grayish to pinkish proximally, occasionally to the midpoint of bill (cf. ML608854099), but usually more restricted, often to a pinkish base to the mandible. The gape and inside of the mouth in adults is bright pink. In nestlings the bill is short and black and the gape swollen and yellow (cf. ML204519091). The bill length slowly grows over the first year and the gape can remain swollen and yellow in juveniles (cf. ML599134781 and images under Juvenile and Formative Plumages).

Iris and Facial Skin

At all ages the iris is dark brown and can look blackish in the field. The orbital skin is pinkish-gray.

Tarsi and Toes

At all ages the legs and feet are dark gray to horn gray with the undersides of the feet sometimes pinkish; rarely, the entire tarsi and toes are pinkish. The claws are dark gray to blackish with paler tips.

Linear Measurements

Total Length

Upupa epops africana: length 25–27 cm

Wing Length

Upupa epops africana: males, mean 140 mm (range 132–145 mm, n = 26); females, mean 135 mm (range 128–140 mm, n = 13; 6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close ).

Upupa epops epops: information needed.

Upupa epops major: males, mean 151 mm ± 4.19 SD (range 145–156 mm, n = 9); female, 148 mm (n = 1; 1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ).

Upupa epops senegalensis: males, mean 137 mm ± 2.50 SD (range 131–141 mm, n = 10); females, mean 131 mm ± 1.67 SD (range 130–134 mm, n = 5; 1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ).

Bill Length

Upupa epops africana: culmen length 42–56 mm (n = 39; 6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close ).

Upupa epops epops: males, mean 50.3 mm ± 6.0 SD (n = 938); females, mean 44.8 mm ± 6.2 SD (n = 1,060; 23 Hildebrandt, B., and M. Schaub (2018). The effects of hatching asynchrony on growth and mortality patterns in Eurasian Hoopoe Upupa epops nestlings. Ibis 160:145–157. Close ).

Upupa epops major: males, mean 57.1 mm ± 1.80 SD (range 54–60 mm, n = 7); female, 52.3 mm (n = 1; 1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ).

Upupa epops senegalensis: males, mean 44.6 mm ± 2.24 SD (range 42–48 mm, n = 10); females, mean 40.6 mm ± 1.70 SD (range 39–43 mm, n = 5; 1 Cramp, S., Editor (1985). The Birds of the Western Palearctic. Volume 4. Oxford University Press, Oxford, UK. Close ).

Tail Length

Upupa epops africana: 84–100 mm (n = 39; 6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close ).

Upupa epops epops: information needed.

Upupa epops major: information needed.

Upupa epops senegalensis: information needed.

Longest Crest Feather Length

Upupa epops africana: information needed.

Upupa epops epops: males, mean 76.6 mm ± 8.1 SD (n = 944); females, mean 73.1 mm ± 9.5 SD (n = 1,053; 23 Hildebrandt, B., and M. Schaub (2018). The effects of hatching asynchrony on growth and mortality patterns in Eurasian Hoopoe Upupa epops nestlings. Ibis 160:145–157. Close ).

Upupa epops major: information needed.

Upupa epops senegalensis: information needed.

Tarsus Length

Upupa epops africana: 16.5–21 mm (n = 39; 6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close ).

Upupa epops epops: males, mean 23.5 mm ± 2.5 SD (n = 846); females, mean 22.2 mm ± 2.9 SD (n = 970; 23 Hildebrandt, B., and M. Schaub (2018). The effects of hatching asynchrony on growth and mortality patterns in Eurasian Hoopoe Upupa epops nestlings. Ibis 160:145–157. Close ).

Upupa epops major: information needed.

Upupa epops senegalensis: information needed.

Mass

The mean mass of 194 adults (males and females combined) in southern Spain was 66.2 g ± 6.0 SD (24 Martín-Vivaldi, M., J. J. Palomino, M. Soler, and J. J. Soler (1999). Determinants of reproductive success in the Hoopoe Upupa epops, a hole-nesting non-passerine bird with asynchronous hatching. Bird Study 46:205–216. Close ). Mass of 12 adults in southern Africa ranged from 46–67.7 g with a mean of 57.3 g (6 Maclean, G. L. (1985). Roberts' Birds of Southern Africa. Fifth edition. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa. Close ). The mean mass of 1,081 adult males in Switzerland was 76.6 g ± 8.1 and that of 1,277 adult females was 73.1 g ± 9.5 SD (23 Hildebrandt, B., and M. Schaub (2018). The effects of hatching asynchrony on growth and mortality patterns in Eurasian Hoopoe Upupa epops nestlings. Ibis 160:145–157. Close ). Also, see Table 1.