Mountain Imperial-Pigeon Ducula badia Scientific name definitions

43–51 cm; 316 g (badia), 580–665 g (griseicapilla). Head, neck and underparts pink, brightest on hindneck and more or less suffused with gray elsewhere; crown and sides of face pale gray; chin and throat white; mantle, lesser and median wing coverts dark reddish purple; back, rump and greater wing coverts dark grayish brown with purple fringes, the purple fades to chestnut in worn plumage; primaries and secondaries blackish brown; tail blackish brown with broad, light gray terminal band; underside of tail gray with silver-gray terminal band; ventral regions and undertail coverts creamy buff; iris white or gray white; orbital skin dark red; bill dark pink or red with paler tip; legs and feet dark red with pale claws. Sexes alike, but female averages smaller. Juvenile duller, head to breast being grayer (less vinous), mantle and wings earth brown with duller chestnut fringes, remiges tipped chestnut, back and rump sooty gray, pale terminal tailband only weakly developed, and feet perhaps paler and more pinkish.

On Java, might be confused with Dark-backed Imperial-Pigeon (Ducula lacernulata), but the latter has distinctly gray crown and ear coverts, contrasting with vinous neck and pinkish-buff throat, mantle and wings entirely brown, undertail coverts darker chestnut and bill uniformly dark.

In the Himalayas and mainland Southeast Asia might also be confused with Speckled Wood-Pigeon (Columba hodgsonii) (much smaller with longer, less rounded wings, and lacks pale gray terminal band) and Ashy Wood-Pigeon (Columba pulchricollis) (also smaller, with darker gray breast and no tail band).

Mountain Imperial-Pigeons have 10 full-length primaries (numbered distally from innermost, p1 to outermost, p10), 10 secondaries (numbered proximally from outermost s1 to innermost s7 and including 3 tertials, numbered distally from t1 to t3), and 12 rectrices (numbered distally, from innermost r1 to outermost r6 on each side of the tail). Geographic variation in appearance is slight (see Systematics: Geographic Variation); the following applies to all subspecies and is based on the descriptions of Baptista et al. (1 Baptista, L. F., P. W. Trail, and H. M. Horblit (1997). Family Columbidae (pigeons and doves). In Handbook of the Birds of the World, Volume 4 (J. del Hoyo, A. Elliott and J. Sargatal, Editors), Lynx Edicions, Barcelona, Spain. pp. 60–243. Close ) and Wells (2 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close ), along with examination of images at the Macaulay Library. See Molts for molt and plumage terminology. Definitive appearance is assumed at Formative or Second Basic Plumage; sexes similar in all plumages although perhaps showing slight average differences in Definitive Basic Plumage (see below). See Higgins and Davies (3 Higgins, P. J., and S. J. J. F. Davies, Editors (1996). Handbook of Australian, New Zealand and Antarctic Birds. Volume 3. Pratincoles to Pigeons. Oxford University Press, Melbourne, Australia. Close ) and Pyle et al. (4 Pyle, P., K. Kayano, K. Tranquillo, K. Murphy, B. Wilcox, and N. Arcilla (2017). Manual for ageing and sexing landbirds of American Samoa, with notes on molt and breeding seasonality. The Institute for Bird Populations, Point Reyes Station, California, USA. Close ) for information on ageing of species within Ducula.

Natal Down

Natal down in hatchlings is pinkish tan.

Juvenile Plumage

Juvenile Plumage is similar to Definitive Basic Plumage but duller, the head to breast being grayer (less vinous); back and upperwing coverts browner and duller, sometimes with chestnut fringes creating mottled or scaled appearance; back and rump sooty gray, pale terminal tail band only weakly developed; remiges sometimes tipped chestnut. As in other Ducula imperial-pigeons, primaries, secondaries, and rectrices are narrower and more rounded at the tips than in later plumages (4 Pyle, P., K. Kayano, K. Tranquillo, K. Murphy, B. Wilcox, and N. Arcilla (2017). Manual for ageing and sexing landbirds of American Samoa, with notes on molt and breeding seasonality. The Institute for Bird Populations, Point Reyes Station, California, USA. Close ).

Formative Plumage

Formative Plumage resembles Definitive Basic Plumage but most individuals undergo incomplete Preformative Molts and can be identified by retained juvenile wing and/or tail feathers. Juvenile outer primaries, outer rectrices, and/or (especially) secondaries among s3-4 and s7-s9 can be retained, narrower, browner, and contrastingly worn, distinguishing formative birds from those in Definitive Basic Plumage with retained basic secondaries (see below).

Definitive Basic Plumage

Head, neck and underparts pink, brightest on hindneck and more or less suffused with gray elsewhere; crown and sides of face pale gray; upper back and upperwing lesser and median coverts dark reddish purple; lower back, rump and greater coverts dark grayish brown with purple fringes, the purple fades to chestnut in worn plumage. Tail from above blackish brown with broad, light gray terminal band; underside of tail gray with silver-gray terminal band. Primaries and secondaries blackish brown. Chin and throat white; remainder of underparts including undertail coverts creamy buff. Definitive basic Females average slightly duller than Males, the back browner and the head and breast with less pink, but overlap in plumages between the sexes appears to occur.

Definitive Basic Plumage is characterized by broader, more truncate, and fresher flight feathers than in Juvenile Plumage. Primaries show molt clines from more worn inner feathers to fresher outer feathers, and may also show two or more sets of feathers reflecting Staffelmauser or stepwise molt (see Molts), the latter indicating Definitive Basic Plumage as opposed to Formative Plumage (4 Pyle, P., K. Kayano, K. Tranquillo, K. Murphy, B. Wilcox, and N. Arcilla (2017). Manual for ageing and sexing landbirds of American Samoa, with notes on molt and breeding seasonality. The Institute for Bird Populations, Point Reyes Station, California, USA. Close ). Secondaries likewise show fresher feathers medially, reflecting molt sequence, or may show mixed patterns of fresh and worn basic feathers, showing slight contrasts in wear but not shape, following Staffelmauser.

General

Molt and plumage terminology follows Humphrey and Parkes (5 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. (6 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: a review of molt and plumage homologies. 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, rather than on molts relative to breeding season, location, or time of the year (see 7 Pyle, P. (2022). Identification Guide to North American Birds. Part I, Second Edition. Slate Creek Press, Forest Knolls, CA, USA. Close ,8 Pyle, P. (2022). Defining moults in migratory birds: a sequence-based approach. Journal of Avian Biology 2022(5):e02958. Close for more information). As in other Ducula imperial-pigeons, Mountain Imperial-Pigeon exhibits a Complex Basic Strategy (cf. 6 Howell, S. N. G., C. Corben, P. Pyle, and D. I. Rogers (2003). The first basic problem: a review of molt and plumage homologies. Condor 105:635–653. Close , 9 Howell, S. N. G. (2010). Molt in North American Birds. Houghton Mifflin Harcourt, Boston, MA and New York, NY, USA. Close ), including incomplete-to-complete preformative and definitive prebasic molts but no prealternate molts (3 Higgins, P. J., and S. J. J. F. Davies, Editors (1996). Handbook of Australian, New Zealand and Antarctic Birds. Volume 3. Pratincoles to Pigeons. Oxford University Press, Melbourne, Australia. Close ,4 Pyle, P., K. Kayano, K. Tranquillo, K. Murphy, B. Wilcox, and N. Arcilla (2017). Manual for ageing and sexing landbirds of American Samoa, with notes on molt and breeding seasonality. The Institute for Bird Populations, Point Reyes Station, California, USA. Close ).

Prejuvenile (First Prebasic) Molt

Complete, in the nest. No information. Presumably completed or near-completed by fledging.

Preformative Molt

Variation in extent not well documented in Mountain Imperial-Pigeon but examination of Macaulay images suggests that it can be incomplete or complete as in other Ducula imperial pigeons (4 Pyle, P., K. Kayano, K. Tranquillo, K. Murphy, B. Wilcox, and N. Arcilla (2017). Manual for ageing and sexing landbirds of American Samoa, with notes on molt and breeding seasonality. The Institute for Bird Populations, Point Reyes Station, California, USA. Close ). When incomplete, outer primaries (among p9-p10), more frequently 1-5 secondaries among s3-s4 and s7-s9, and one or more juvenile rectrices may be expected to be retained.

Definitive Prebasic Molt

Incomplete to complete. On the Malay Peninsula molt was recorded in March-May and October (2 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close ). Primaries replaced distally (p1 to p10), secondaries replaced proximally from s1 and distally from the tertials (often bilaterally from the second tertial, t2), and rectrices generally replaced distally (r1 to r6) on each side of tail, with some variation in rectrix sequence possible. Following incomplete molts, Staffelmauser or stepwise molt (see 10 Pyle, P. (2006). Staffelmauser and other adaptive strategies for wing molt in larger birds. Western Birds 37(3):179–185. Close ), in which two or more waves of primaries can molt simultaneously, can result in some individuals, as in other Ducula imperial-pigeons (11 Marchant, S., and P. J. Higgins, eds. (1993). Handbook of Australian, New Zealand and Antarctic Birds. Vol. 2. Oxford University Press, Melbourne. Close , 2 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close , 4 Pyle, P., K. Kayano, K. Tranquillo, K. Murphy, B. Wilcox, and N. Arcilla (2017). Manual for ageing and sexing landbirds of American Samoa, with notes on molt and breeding seasonality. The Institute for Bird Populations, Point Reyes Station, California, USA. Close ).

Bill

The bill of adults is dark pink or red with paler tip.

Iris and Facial Skin

In juveniles, the iris is dull brownish or tinged olive. In adults, the iris is white or grayish white and the orbital skin is dark red.

Tarsi and Toes

Dark red with pale claws; paler, pinkish red in juveniles.

Hitherto considered conspecific with Malabar Imperial-Pigeon (Ducula cuprea); in their assessment, del Hoyo and Collar (12 del Hoyo, J., and N. J. Collar (2014). HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1. Non-passerines. Lynx Edicions, Barcelona, Spain. Close ), employing the Tobias et al. (13 Tobias, J. A., N. Seddon, C. N. Spottiswoode, J. D. Pilgrim, L. D. C. Fishpool, and N. J. Collar (2010). Quantitative criteria for species delimitation. Ibis 152(4):724–746. Close ) criteria, from which the numbers in brackets are derived, Ducula badia differs in its pale versus dark iris [3]; grayer underparts [2]; purplish mantle [1]; slightly longer wing and slightly shorter bill, effect size –0.91 for wing [1], 0.6 for bill [1]; and broader terminal tail-band of Ducula cuprea (mean 45.5 versus 38.5 mm, effect size –1.7, ns[1]). In addition to the morphological differences, Niranjana and Praveen (14 Niranjana C. and J. Praveen (2021). Vocalisation of Mountain Imperial Pigeon Ducula badia and its taxonomic implications. Indian BIRDS 17 (3): 70–72. Close ) found differences in the vocalizations between Ducula badia and Ducula cuprea consistent with species-status, with Ducula cuprea singing longer songs than any of the subspecies of Ducula badia, which are all similar to each other. Probably closely related to Dark-backed Imperial-Pigeon (Ducula lacernulata) and Timor Imperial-Pigeon (Ducula cineracea).

Proposed subspecies carolinae (eastern Naga Hills, in northeastern India) and obscurata (southeastern Thailand) are synonymized with griseicapilla, and proposed subspecies capistrata (western Java) is synonymized with nominate (15 Gibbs, D., E. Barnes, and J. Cox (2001). Pigeons and Doves: A Guide to the Pigeons and Doves of the World. Pica Press, Robertsbridge, UK. Close ). Three subspecies recognized.

---

SUBSPECIES

Ducula badia insignis Scientific name definitions

Distribution

Central Nepal, Sikkim, and Bhutan east to Meghalaya (Khasia Hills) and Brahmaputra River.

Identification Summary

Subspecies insignis resembles griseicapilla (and intergrades with it in Assam) but has an entirely dark vinous head and neck, the mantle has faint purplish wash like griseicapilla (albeit less intense) and underparts also like griseicapilla; the iris is pale to pale bluish gray, with the orbital skin purple gray, becoming purer gray close to eye.

---

SUBSPECIES

Ducula badia griseicapilla Scientific name definitions

Distribution

Northeastern India (Nagaland, Manipur), Myanmar (south to northern Tennasserim) and Thailand east to south-central China (southwestern Yunnan, Hainan), and south to Laos, Vietnam, and Cambodia.

Identification Summary

Subspecies<em>griseicapilla</em> has extensive purple areas on the upperparts, a gray tinge to the rump, a pale gray crown and face contrasting with a pink hindneck, pale gray underparts, and cream undertail coverts.

---

SUBSPECIES

Ducula badia badia Scientific name definitions

Distribution

Southern Tenasserim and Mergui Archipelago south through Malay Peninsula to Sumatra, Borneo, and western Java.

Likely closely related to Ducula cuprea, but these species have not been included in a molecular phylogeny together. In one study that sampled Ducula badia, its phylogenetic position was unresolved, forming a polytomy near the base of the Ducula tree (16 Cibois, A., J-C. Thibault, C. Bonillo, C. E. Filardi, and E. Pasquet (2017). Phylogeny and biogeography of the imperial pigeons (Aves: Columbidae) in the Pacific Ocean. Molecular Phylogenetics and Evolution 110:19-26 Close ).

Distributed from central Nepal (few records), Sikkim, and Bhutan, east to Arunachal Pradesh, India, northern Myanmar, to southwestern Yunnan and Hainan in China, and south through Vietnam, Laos, Cambodia, Thailand, southern Myanmar and the Mergui Archipelago, through the Malay Peninsula to Sumatra, Borneo, and western Java.

Occurs on Pulau Nias, and presence on other Sumatran islands of Siberut and Enggano requires confirmation.

Extralimital Records

Only doubtfully reported from Orissa, northeastern India. There are outlying observations from beyond the known breeding range; in the Chittagong Hills, southeastern Bangladesh, the species was first discovered in 2000 and appears to be resident in small numbers, although most records are in November–March (17 Thompson, P. M., and D. L. Johnson (2003). Further notable bird records from Bangladesh. Forktail 19:85–102. Close , 18 Thompson, P. M., S. U. Chowdhury, E. Ul Haque, M. M. H. Khan, and R. Halder (2014). Notable bird records from Bangladesh from July 2002 to July 2013. Forktail 30:50–65. Close ), and from lowlands of southwestern Guangxi, southern China (May 1998) (19 Lee Kwok Shing, Lau, M.W.-N., Fellowes, J.R. and Chan Bosco Pui Lok (2006). Forest bird fauna of South China: notes on current distribution and status. Forktail. 22: 23–38. Close ), eBird. One record of a bird flying low above sea near Pulau Tiga (off northeastern Borneo).

Mature primary and secondary evergreen and deciduous forests from foothills (generally above 400 m) up to 2300 m in Indian Subcontinent (occasionally 2500 m in Bhutan), or 2200 on Sumatra; on Sumatra, Borneo, and western Java and in some other areas, often visits lowlands and coastal mangroves, perhaps seasonally; rarely enters scrub forests and also occurs in conifers and old rubber plantations on Borneo.

In India, seasonally undertakes local and altitudinal movements in response to fruit availability, and occurrence at individual localities in Bhutan is considered erratic and all records there above 1600 m are suggestive of dispersal and are in months of March and July. On Borneo and Sumatra, coastal birds make daily trips inland, and montane birds make daily trips to lowland feeding areas (former type of movements, over 30–40 km, also occur in Peninsular Malaysia); in Sabah, the species is particularly abundant in coastal mangroves in October–February.

Generally appears to be resident.

Food Capture and Consumption

Typically seen in pairs or small flocks in upper canopy, sometimes in company of Green Imperial-Pigeon (Ducula aenea) and Large Green-Pigeon (Treron capellei) (Peninsular Malaysia).

Major Food Items

Frugivorous , feeding on a variety of fruits and berries, especially figs (e.g., Ficus crassiramea and F. cucurbitina) and wild nutmegs, as well as occasional buds and young leaves though confirmation of latter foods required; in Arunachal Pradesh, eastern Himalayas, disperses seeds of following trees: Chisocheton paniculatus, Dysoxylum binectariferum (Meliaceae) and Polyalthia simiarum (Annonaceae) (20 Sethi, P. and Howe, H.F. (2009). Recruitment of hornbill-dispersed trees in hunted and logged forests of the Indian Eastern Himalaya. Conservation Biology. 23(3): 710–718. Close ).

Occasionally descends to ground to drink.

Vocal Development

No information.

Vocal Array

Advertisement call. A repeated low-pitched rhythmic phrase of three resonant somewhat muffled hoots hu..hwuU..hwuu. First note is shorter and fainter than second and third. Each note is upward inflected and modulated, but this may be inaudible in the first note, and last note sometimes less modulated than second. Most energy of hoots between 200 and 300Hz. Pause between first two notes much shorter than between last two notes; total phrase duration about 1.1‒1.5s and second pause 0.24-0.59s (14 Niranjana C. and J. Praveen (2021). Vocalisation of Mountain Imperial Pigeon Ducula badia and its taxonomic implications. Indian BIRDS 17 (3): 70–72. Close ). This phrase is typically repeated several times with intervals of a few to several seconds. Two- or four-note variants occur , while the first note can be inaudible from a distance.

Grunt. A faint low-pitched grunt has been heard.

Other. Besides the Advertisement call (Perch-coo), one may expect a somewhat different Bow-coo and/or Nest-coo, in analogy with other members of the pigeon family (Columbidae). It is unclear whether e.g. the occasionally heard two-note phrase refers to such a vocalization, or whether this is merely an individual variation. More detailed observations of a breeding pair are required to get a better understanding of the full repertoire.

Geographic Variation

The three-note Advertisement call is remarkably uniform over the large range of this species. Voice of the morphologically fairly distinct allopatric taxon cuprea was long poorly documented and basically known solely from transcriptions (21 Rasmussen, P. C., and J. C. Anderton (2012). Birds of South Asia: the Ripley Guide. Volumes 1 and 2. Second edition. National Museum of Natural History, Washington, D.C., USA, Smithsonian Institution, Michigan State University, Ann Arbor, MI, USA, and Lynx Edicions, Barcelona, Spain. Close ), but meanwhile several sound recordings have become available that document an Advertisement call which is structurally similar. A detailed comparison did reveal some consistent differences: the interval between second and third hoot is longer (0.45‒0.81s vs. 0.24‒0.59s for the other taxa) and so is the total phrase duration (1.52‒1.86s vs. 1.13‒1.53s). Hence, the Advertisement call of cuprea is audibly less hurried than that of the other three taxa (14 Niranjana C. and J. Praveen (2021). Vocalisation of Mountain Imperial Pigeon Ducula badia and its taxonomic implications. Indian BIRDS 17 (3): 70–72. Close ). This additional difference led to its present treatment as a distinct species Malabar Imperial-Pigeon (Ducula cuprea). The less commonly heard two- or four-note phrases do not seem to be confined to a particular region. Temporal parameters of the Advertisement call have largely overlapping values in the three taxa of present species (14 Niranjana C. and J. Praveen (2021). Vocalisation of Mountain Imperial Pigeon Ducula badia and its taxonomic implications. Indian BIRDS 17 (3): 70–72. Close ).

Phenology

Vocal during most of the year, but increasingly so during the breeding period.

Daily Pattern of Vocalizing

Mainly vocal during (early) morning and again in late afternoon.

Places of Vocalizing

Advertisement call is given from an exposed perch in the top of the canopy, and often answered by neighboring individuals. The second note is given as the puffed neck lunges deeply forward, the third note as it tucks back upright again (22 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Academic Press, San Diego, CA, USA. Close ).

Sex Differences

No information.

Social Content and Presumed Functions of Vocalizations

Little information. Advertisement call (Perch-coo), the long-distance vocalization, is given in territorial advertisement and presumably also for mate attraction. Pair members make short-range contact with a Grunt (2 Wells, D. R. (1999). The Birds of the Thai-Malay Peninsula. Volume 1. Non-passerines. Academic Press, London, UK. Close ).

During flight display over the forest, birds make clapping sounds with the wings (23 Davison, G. W. H. (1992). Birds of Mount Kinabalu. Borneo. Natural History Publications (Borneo) Sdn. Bhd. and Koktas Sabah Berhad, Kota Kinabalu and Ranau, Indonesia. Close ).

Flight

A powerful flier, often seen in sustained flights well above the canopy.

Courtship, Copulation, and Pair Bond

Display-flight involves bird flapping wings rapidly, then sweeps up vertically for 6–8 m, before abruptly turning and diving down with spread tail, before repeating the display 2–3 times.

Degree of Sociality

Typically seen in pairs or small flocks in upper canopy, sometimes in company of Green Imperial-Pigeon (Ducula aenea) and Large Green-Pigeon (Treron capellei) (Peninsular Malaysia), but record of 65 together in Bhutan and roosts of 200–300 birds together in mangroves on Borneo.

Season apparently extended; for subspecies insignis reported to be March–August; on Sumatra and Borneo, in January–April and June, and in Peninsular Malaysia, in December–April and June–September (subspecies badia).

Site Characteristics

Nest is placed 3–8 m up in a sapling or understory tree, including pandans or tree-ferns, once over a road.

Structure and Composition

Nest is a slight platform of twigs.

Dimensions

20–25 cm across.

Size

40·8 mm × 30 mm.

Color and Surface Texture

White.

Clutch Size

One, exceptionally two.

Parental Behavior

Egg is incubated by both sexes.

Information from across its range is rather limited but species reported to be the most common large pigeon of foothill and montane forest on Borneo and Sumatra; considered rare in Java. Common in Thailand, although numbers have been reduced by hunting; also common in mountains of Malay Peninsula. Despite it's relative abundance, its population is thought to be decreasing (24 BirdLife International (2022) Species factsheet: Ducula badia. Downloaded from http://www.birdlife.org on 10/10/2022. Close ).

Not globally threatened (Least Concern).