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The great hornbill (''Buceros bicornis''), also known as the concave-casqued hornbill, great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family. It occurs in the Indian subcontinent and Southeast Asia. It is predominantly frugivorous, but also preys on small mammals, reptiles and birds. It has been listed as Vulnerable on the IUCN Red List since 2018. It is known to have lived for nearly 50 years in captivity. Due to its large size and colour, it is important in many tribal cultures and rituals. The Government of Kerala declared it as the official Kerala state bird.


Taxonomy

The great hornbill was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his '' Systema Naturae''. He placed it with the
rhinoceros hornbill The rhinoceros hornbill (''Buceros rhinoceros'') is a large species of forest hornbill (Bucerotidae). In captivity it can live for up to 35 years. It is found in lowland and montane, tropical and subtropical climates and in mountain rain forests ...
in the genus '' Buceros'' and coined the binomial name ''Buceros bicornis''. Linnaeus specified the
location In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ...
as China. The genus name is from Latin ''becerus'' meaning "horned like an ox" which in turn is from the Ancient Greek boukerōs which combines ''bous'' meaning "ox" with ''kerōs'' meaning "horn". The specific ''bicornis'' is Latin and means "two-horned". The species is monotypic: no subspecies are recognised. The species was formerly broken into subspecies ''cavatus'', from the Western Ghats, and ''homrai'', the nominate form from the sub-Himalayan forests. The subspecies from Sumatra was sometimes called ''cristatus''. Variation across populations is mainly in size, Himalayan birds being larger than those from further south, and the species is now usually considered monotypic.


Description

The great hornbill is a large bird, long, with a wingspan and a weight of . The average weight of 7 males is whereas that of 3 females is . It is the heaviest, but not the longest, Asian hornbill. Females are smaller than males and have bluish-white instead of red eyes, although the orbital skin is pinkish. Like other hornbills, they have prominent "eyelashes". The most prominent feature of the hornbill is the bright yellow and black
casque Casque is a French word for helmet. It can refer to: * Casque (anatomy), an enlargement on the beaks of some species of birds, including many hornbills *Hornbill ivory, the casque of the helmeted hornbill, collected as a decorative material * S. C ...
on top of its massive bill. The casque appears U-shaped when viewed from the front, and the top is concave, with two ridges along the sides that form points in the front, whence the Latin species epithet ''bicornis'' (two-horned). The back of the casque is reddish in females, while the underside of the front and back of the casque is black in males. The casque is hollow and serves no known purpose, although it is thought to be the result of sexual selection. Male hornbills indulge in aerial casque butting, with birds striking each other in flight. The male spreads the preen gland secretion, which is yellow, onto the primary feathers and bill to give them the bright yellow colour. The
commissure A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. * The most common usage of the term refers to the brain's commissures, of which there are five. Such a commi ...
of the beak is black and has a serrated edge which becomes worn with age. The wing beats are heavy, and the sound produced by birds in flight can be heard from a distance. This sound has been likened to the puffing of a steam locomotive starting up. The flight involves stiff flaps followed by glides with the fingers splayed and upcurled. Like other members of the hornbill family, they have highly
pneumatized bones Skeletal pneumaticity is the presence of air spaces within bones. It is generally produced during development by excavation of bone by pneumatic diverticula (air sacs) from an air-filled space, such as the lungs or nasal cavity. Pneumatization is h ...
, with hollow air cavities extending to the tips of the wing bones. This anatomical feature was noted by
Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Owe ...
, who dissected a specimen that died at the Zoological Society of London in 1833.


Distribution and habitat

The great hornbill is native to the forests of
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
,
Bhutan Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainous ...
,
Nepal Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne, सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
,
mainland Southeast Asia Mainland Southeast Asia, also known as the Indochinese Peninsula or Indochina, is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west an ...
and
Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...
. Its distribution is fragmented in the Western Ghats and in the foothills of the Himalayas. Deforestation has reduced its range in many parts of India such as in the Kolli hills where it was recorded in the 1860s. It prefers dense old growth unlogged forests in hilly regions. It appears to be dependent on large stretches of rain forests. In Thailand, the
home range A home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. He ...
of males was found to be about during the breeding season and about during the non-breeding season. Molecular approaches to the study of its population diversity have been attempted.


Behaviour and ecology


Food and feeding

Great hornbills are usually seen in small parties, with larger groups sometimes aggregating at fruit trees. A congregation of 150 to 200 birds has been recorded in southeastern Bhutan. In the wild, the great hornbill's diet consists mainly of fruit.
Figs The fig is the edible fruit of ''Ficus carica'', a species of small tree in the flowering plant family Moraceae. Native to the Mediterranean and western Asia, it has been cultivated since ancient times and is now widely grown throughout the world ...
are particularly important as a food source. ''
Vitex altissima ''Vitex altissima'', the peacock chaste tree, is a species of woody plant reaching some 20 m in height, in the family Lamiaceae. It is native to the Indomalayan realm, namely Bangladesh, India, Indonesia, Myanmar, and Sri Lanka, and is also found ...
'' has been noted as another important food source. Great hornbills also forage on lipid-rich fruits of the families
Lauraceae Lauraceae, or the laurels, is a plant family that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45 genera worldwide (Christenhusz & Byng 2016 ). They are dicotyledons, and occur ma ...
and
Myristicaceae The Myristicaceae are a family of flowering plants native to Africa, Asia, Pacific islands, and the Americas and has been recognized by most taxonomists. It is sometimes called the "nutmeg family", after its most famous member, ''Myristica fragra ...
such as '' Persea'', '' Alseodaphne'' and ''
Myristica ''Myristica'' is a genus of trees in the family Myristicaceae. There are over 150 species, distributed in Asia and the western Pacific. The type species of the genus, and the most economically important member, is ''Myristica fragrans'' (the nut ...
''. They obtain water entirely from their diet of fruits. They are important dispersers of many forest tree species. They will also eat small mammals, birds, small reptiles and insects. Lion-tailed macaques have been seen to forage alongside these hornbills. They forage along branches, moving along by hopping, looking for insects, nestling birds and small lizards, tearing up bark and examining them. Prey are caught, tossed in the air and swallowed. A rare squirrel, the
Travancore flying squirrel Travancore flying squirrel (''Petinomys fuscocapillus''), also known as the small flying squirrel, is a flying squirrel found in South India and Sri Lanka. Travancore flying squirrels were thought to be extinct but were rediscovered in 1989 aft ...
(''Petinomys fuscocapillus'') has been eaten, and Indian scops owl (''Otus bakkamoena''),
jungle owlet The jungle owlet (''Glaucidium radiatum'') or barred jungle owlet is native to the Indian Subcontinent. The species is often found singly, in pairs or small groups and they are usually detected by their calls at dawn and dusk. There are two subsp ...
(''Glaucidium radiatum'') and
Sri Lanka green pigeon The Sri Lanka green pigeon or Ceylon green pigeon (''Treron pompadora'') is a pigeon in the genus '' Treron''. In Sri Lanka, this bird and several other green pigeon are known as ''bata goya'' in the Sinhala language. It is found in the forests ...
(''Treron pompadora'') have been taken as prey in the Western Ghats.


Breeding

During the breeding season (January to April) great hornbills become very vocal. They make loud duets, beginning with a loud "kok" given about once a second by the male, to which the female joins in. The pair then calls in unison, turning into a rapid mixture of roars and barks. They prefer mature forests for nesting. Large, tall and old trees, particularly emergents that rise above the canopy, seem to be preferred for nesting. They form monogamous pair bonds and live in small groups of 2-40 individuals. Group courtship displays involving up to 20 birds have been observed. The female hornbill builds a nest in the hollow of a large tree trunk, sealing the opening with a plaster made up mainly of feces. She remains imprisoned there, relying on the male to bring her food, until the chicks are half developed. During this period the female undergoes a complete moult. The young chicks have no feathers and appear very plump. The mother is fed by her mate through a slit in the seal. The clutch consists of one or two eggs, which she incubates for 38–40 days. The female voids feces through the nest slit, as do the chicks from the age of two weeks. Once the female emerges from the nest, the chicks seal it again. The young birds have no trace of a casque. After the second year the front extremity separates from the culmen, and in the third year it becomes a transverse crescent with the two edges growing outwards and upwards, while the anterior widens to the width of the rear end. Full development takes five years.


Roosting

Roost sites are used regularly and birds arrive punctually at sunset from long distances, following the same routes each day. Several tall trees in the vicinity may be used, the birds choosing the highest branches with little foliage. They jockey for position until late at dusk. When sleeping they draw their neck back and the bill is held upwards at an angle.


Threats

The great hornbill is threatened mainly by habitat loss due to deforestation. It is hunted for its meat, fat and body parts like casque and tail feathers, which are used as adornments. Tribal peoples hunt the great Indian hornbill for its various parts. The beaks and head are used in charms and the flesh is believed to be medicinal. Young birds are considered a delicacy. Declines in population have been noted in many areas such as Cambodia. Tribesmen in parts of northeastern India use the feathers for head-dresses, and the skulls are often worn as decorations. The Sema Nagas consider the flesh unfit for eating, believing that it produces sores on their feet, as in the bird. When dancing with the feathers of the hornbill, they avoid eating vegetables, as doing so is also believed to produce the same sores on the feet.


Conservation

The great hornbill is listed in
CITES Appendix I CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
. It has been listed as Vulnerable on the IUCN Red List since 2018. Conservation programmes have attempted to provide tribes with feathers from captive hornbills and ceramic casques to substitute for natural ones.


In captivity

Very few hornbills are held in captivity, and few of them breed well. Females at the nests are extremely easy to capture, and birds caught in the wild are mostly female. Breeding them in captivity has been notoriously difficult, with fewer than a dozen successful attempts. Their extreme selectivity for mates and their long and strong pair bonds make them difficult to maintain for breeding. Captive great hornbills eat fruits and meat, a healthy diet consisting mostly of fruit and some source of protein. A few have been
tamed A tame animal is an animal that is relatively tolerant of human presence. Tameness may arise naturally (as in the case, for example, of island tameness) or due to the deliberate, human-directed process of training an animal against its initially ...
in captivity but their behaviour in captivity is described as highly strung. Captive specimens bask in the sun with outstretched wings.


In culture

The great hornbill is called ''homrai'' in Nepal and ''banrao'' in
Mussoorie Mussoorie is a hill station and a municipal board, near Dehradun city in the Dehradun district of the Indian state of Uttarakhand. It is about from the state capital of Dehradun and north of the national capital of New Delhi. The hill s ...
, both meaning "King of the Jungle". It is the official state bird of the Indian states of Kerala and
Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...
.


Use as a symbol

A great hornbill named William was the model for the logo of the
Bombay Natural History Society The Bombay Natural History Society (BNHS), founded on 15 September 1883, is one of the largest non-governmental organisations in India engaged in conservation and biodiversity research. It supports many research efforts through grants and publi ...
and the name of the society's building. Norman Kinnear described William as follows in the obituary of
Walter Samuel Millard Walter Samuel Millard (1864–1952) was a British entrepreneur and naturalist who was honorary secretary of the Bombay Natural History Society, editor of the ''Journal of the Bombay Natural History Society'' from 1906 to 1920, co-author (with E ...
: "Every visitor to the Society's room in Apollo Street will remember the Great Indian Hornbill, better known as the "office canary" which lived in a cage behind Millard's chair in Phipson & Co.'s office for 26 years and died in 1920. It is said its death was caused by swallowing a piece of wire, but in the past "William" had swallowed a lighted cigar without ill effects and I for my part think that the loss of his old friend was the principal cause."


References


Other sources

* Kannan, R. (1993). "Saving the Great Indian Hornbill". Hornbill magazine. Bombay Natural History Society 1993(4):4–7. * Kannan, R. (1994). "Ecology and Conservation of the Great Pied Hornbill (''Buceros bicornis'') in the Western Ghats of southern India". Ph.D. Thesis, University of Arkansas, Fayetteville. * Kannan, Ragupathy (1994). "Conservation ecology of the Great Hornbill in the Western Ghats, southern India". OBC Bull. 19: 13. * Kannan, R. and James, D. A. (2007). "Phenological studies of hornbill fruit trees in tropical rainforests: methodologies, problems, and pitfalls". pp 155–166 in Kemp, A.C. and M.I. Kemp (Eds.). The Active Management of Hornbills for Conservation. CD-ROM Proceedings of the 4th International Hornbill Conference, Mabula Game Lodge, Bela Bela, South Africa. Naturalists and Nomads, Pretoria. * Kannan, R. and James, D. A. (2008). "Fig trees (''Ficus''), captive elephants, and conservation of hornbills and other frugivores in an Indian wildlife sanctuary". J. Bombay. Nat. Hist. Soc. 105(2):238-242. https://www.biodiversitylibrary.org/page/48379127#page/118/mode/1up * Poonswad, P. (1995). "Nest site characteristics of four sympatric species of hornbills in Khao Yai National Park, Thailand". Ibis 137: 183–191.


External links

* * {{Taxonbar, from=Q232768
great hornbill The great hornbill (''Buceros bicornis''), also known as the concave-casqued hornbill, great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family. It occurs in the Indian subcontinent and Southeast Asia. It ...
great hornbill The great hornbill (''Buceros bicornis''), also known as the concave-casqued hornbill, great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family. It occurs in the Indian subcontinent and Southeast Asia. It ...
Birds of India Birds of Southeast Asia
great hornbill The great hornbill (''Buceros bicornis''), also known as the concave-casqued hornbill, great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family. It occurs in the Indian subcontinent and Southeast Asia. It ...
great hornbill The great hornbill (''Buceros bicornis''), also known as the concave-casqued hornbill, great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family. It occurs in the Indian subcontinent and Southeast Asia. It ...
Symbols of Arunachal Pradesh Birds of Myanmar