Except for the time during nesting season, Buceros bicornis vocalizes very loudly. The sounds they produce can be described as "cackling" or "roaring." Great hornbills are most vocal within large, communal night roosts. Roosts are often hypothesized to be "information hubs" where individuals can share information regarding good feeding sites, for example. Pairs of great hornbills use duets as part of courtship, where a male and female alternate calls to each other. The location of individuals can be identified by sound alone due to their vocalizations combined with the characteristic "whooshing" sound produced by their flight. This unique flight sound is produced from lack of flight feather coverts.
Male great hornbills use tactile forms of communication to compete for mates. Males collide bill casques, often in flight, during the time preceding the breeding season. The size of male bill casques also likely serves as visual communication to potential mates. Like all birds, great hornbills perceive their environments through visual, tactile, auditory and chemical stimuli.
Communication Channels: visual ; tactile ; acoustic
Other Communication Modes: duets
Perception Channels: visual ; tactile ; acoustic ; chemical
Buceros bicornis is considered "near threatened" on the IUCN Red List. The biggest threat to this species is habitat destruction, and particularly the removal of the old-growth trees that these birds require for nesting. Their large size and distinctive sounds make great hornbills relatively easy targets for hunters, who value them for their meat, feathers and casque, which is used for ornamental purposes among natives. They are listed under CITES appendix I which restricts trade of the species for exceptional purposes only.
CITES: appendix i
IUCN Red List of Threatened Species: near threatened
There are no known adverse effects of Buceros bicornis on humans.
Buceros bicornis is kept in zoos in various parts of the world. Efforts to breed this species in captivity are generally not successful.
The casque of B. bicornis is used as an ornamental piece by natives. They are also occasionally hunted for their meat and feathers for subsistence, ritualistic or medicinal purposes.
They are also an important seed disperser which aids in forest propagation.
Positive Impacts: body parts are source of valuable material
Due to its large gape, Buceros bicornis is able to transport and disperse seeds of trees in the genus Myristica, which tend to be too large for other organisms. These trees rely on B. bicornis for seed dispersal since only a few other birds (such as Ocyceros griseus) are able to ingest the seeds intact to later disperse. They also impact populations of small mammals, birds, amphibians, reptiles and insects that they occasionally consume.
Ecosystem Impact: disperses seeds
Members of this species are predominantly frugivores that feed on both lipid-rich and sugar-rich fruits but feed on small mammals, birds, amphibians, reptiles, and insects as well. The lipid-rich fruits include those in the genus Knema and Myristica commonly known as nutmeg trees, and several in the family Lauraceae such as Beilschmiedia. Though these lipid-rich fruits may be available throughout the year, they are particularly abundant during the breeding season. As a result, B. bicornis relies on these fruits as its primary source of energy during the breeding season when energy needs are significantly higher for both the parents and young. This is also true for other hornbill species in the same region, such as Malabar gray hornbills (Ocyceros griseus).
During the rest of the year, great hornbills rely on sugar-rich fruits such those of Vitex altissima and several species in the genus Ficus (fig trees). Figs account for the majority of fruit consumption of B. bicornis throughout the year. Great hornbills have been known to protect fig trees from other birds such as wreathed hornbills (Rhyticeros undulatus).
Animal Foods: birds; mammals; amphibians; reptiles; insects
Plant Foods: fruit
Primary Diet: herbivore (Frugivore )
Buceros bicornis is found in mainland Southeast Asia, the Malay Peninsula and Indonesia. They are breeding residents in Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Thailand and Vietnam. In India, they and several other hornbill species live in the Western Ghats mountain range and forests in both the northeastern and southern regions.
Biogeographic Regions: oriental (Native )
Great hornbills are arboreal and live mainly in wet, tall, evergreen forests. Old-growth trees that extend beyond the height of the canopy are preferred for nesting. The height of the tree and the presence of a natural cavity large enough to hold a female and her eggs are more important than the type of tree. The same nesting site is used year after year if possible. They are known to inhabit elevations of 600 to 2000 m.
Range elevation: 600 to 2000 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Buceros bicornis may live up to fifty years of age in captivity, but range from 35 to 40 in the wild. Though B. bicornis may occasionally be hunted by man, they lack natural predators and their food is often plentiful. These two things allow for a relatively long lifespan.
Typical lifespan
Status: wild: 35 to 40 years.
Typical lifespan
Status: captivity: 50 (high) years.
Great hornbills are fairly large, ranging from 95 to 120 cm in length and featuring a wingspan of 151 to 178 cm. On average, they weigh 3 kg. They are vividly colored and easily recognizable. The body, head, and wings are primarily black; the abdomen and neck are white. The tail is white and is crossed by a subterminal black band. A preen gland near the tail secretes tinted oil, which is spread across the feathers by the bird during grooming. This may give the bill, neck, casque, and tail and wing feathers coloration varying from yellow to red. The most recognizable feature of hornbills is the casque, which is a hollow structure located on top of the bill. It may be used by males to fight with other males and attract females. Like many other hornbills, these birds have prominent eyelashes.
Males and females are similar except that the irises of males are red while those of females are white, and males have slightly larger bills and casques.
The feature that distinguishes B. bicornis from other species is its greatly curved bill and prominent casque.
Average mass: 3 kg.
Range length: 95 to 120 cm.
Range wingspan: 151 to 178 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; sexes colored or patterned differently; ornamentation
Buceros bicornis has few if any natural predators due to its relatively large size and the fact that members of this species tend to occupy the canopy. However, humans occasionally hunt and kill great hornbills for their meat, casque, and feathers for subsistence, medicinal, or ritualistic purposes.
Known Predators:
Great hornbills breed between the months of February and May. Male casque size is important in attracting and fighting for mates. Males compete for females by butting into each other in the presence of a female prior to the breeding season. This could possibly be a display of superiority in competition for a mate. Mates, or potential mates, also perform duets where the male calls, the female replies, and they continue on in a loud volley. Buceros bicornis tends to be monogamous, and the pair remains together throughout their lives.
Mating System: monogamous
A unique feature of Buceros bicornis and some other hornbill species such as Buceros rhinoceros is the way that the female incubates and cares for her eggs. During the breeding period, which lasts between February and May, a monogamous pair chooses a tree in which to lay the eggs. This tree is usually a very tall, old-growth tree and the same one is used every year if possible.
After finding a hole in the tree that is large enough, the female uses both her own feces and her mate's to cover the entrance from the inside, thus confining herself inside. She makes a small slit through which the male provides food. In captivity, B. bicornis may use soft fruits such as bananas in addition to feces to cover the hole. While inside the hole, the female lays and then incubates on average two eggs. The male provides fruits from trees in the genus Beilschmiedia, which are widely available during the breeding season; she receives no nutrients other than this. In other hornbill species such as Buceros hydrocorax, other non-breeding birds in addition to the male may provide assistance by bringing fruit to a female incubating her eggs. The incubation period usually lasts between 38 and 40 days. Protected within the tree, the female completes a full molt which renders her flightless for a period of time.
After the chicks hatch, the female remains confined in the tree for around five weeks when she emerges to help the male gather food for the growing young. The young re-seal themselves within the cavity after the female leaves. For the next two weeks, the both parents provide food for the young. After the young emerge, the parents continue to feed them until they reach roughly 15 weeks of age, at which point they are considered independent.
Breeding interval: Great Hornbills breed once a year.
Breeding season: Breeding occurs between February and May.
Range eggs per season: 1 to 2.
Average eggs per season: 2.
Range time to hatching: 38 to 40 days.
Average time to independence: 15 weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Parental investment in this species consists of providing food for young throughout the time period between hatching and independence. The mother is confined within the nest tree for a few weeks during the pre-hatching period, which usually lasts a few weeks, and for approximately five weeks after hatching.
During these periods, the male provides food while the female and young are protected in the tree. The male must forage extensively for lipid-rich fruits in order to feed himself as well as the female and the young. The male and female continue to feed the young throughout the pre-independence period until roughly fifteen weeks of age.
Great hornbills also invest energy in defending a nesting territory. They are only territorial during the breeding season, and may defend a 100 m area around the nest.
Parental Investment: altricial ; male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents
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.
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 in the genus Buceros and coined the binomial name Buceros bicornis. Linnaeus specified the location as China.[3] 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".[4] The species is monotypic: no subspecies are recognised.[5]
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.[6] Variation across populations is mainly in size, Himalayan birds being larger than those from further south, and the species is now usually considered monotypic.[7][8]
The great hornbill is a large bird, 95–130 cm (37–51 in) long, with a 152 cm (60 in) wingspan and a weight of 2 to 4 kg (4.4 to 8.8 lb). The average weight of 7 males is 3 kg (6.6 lb) whereas that of 3 females is 2.59 kg (5.7 lb).[9] It is the heaviest, but not the longest, Asian hornbill.[9][10] 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 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.[11] The male spreads the preen gland secretion, which is yellow, onto the primary feathers and bill to give them the bright yellow colour.[12] The commissure 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.[13][14]
Like other members of the hornbill family, they have highly pneumatized bones, with hollow air cavities extending to the tips of the wing bones. This anatomical feature was noted by Richard Owen, who dissected a specimen that died at the Zoological Society of London in 1833.[15]
The great hornbill is native to the forests of India, Bhutan, Nepal, mainland Southeast Asia and Sumatra.[16] 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.[17]
It prefers dense old growth unlogged forests in hilly regions.[18][19] It appears to be dependent on large stretches of rain forests.[20]
In Thailand, the home range of males was found to be about 3.7 km (2.3 mi) during the breeding season and about 14.7 km (9.1 mi) during the non-breeding season.[21] Molecular approaches to the study of its population diversity have been attempted.[22]
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.[13] In the wild, the great hornbill's diet consists mainly of fruit. Figs are particularly important as a food source.[23] Vitex altissima has been noted as another important food source. Great hornbills also forage on lipid-rich fruits of the families Lauraceae and Myristicaceae such as Persea, Alseodaphne and Myristica.[24] They obtain water entirely from their diet of fruits. They are important dispersers of many forest tree species.[25] They will also eat small mammals, birds,[26] small reptiles and insects.[27] Lion-tailed macaques have been seen to forage alongside these hornbills.[28]
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 (Petinomys fuscocapillus) has been eaten, and Indian scops owl (Otus bakkamoena), jungle owlet (Glaucidium radiatum) and Sri Lanka green pigeon (Treron pompadora) have been taken as prey in the Western Ghats.[29]
_Photograph_by_Shantanu_Kuveskar.jpg)
Close-up of great hornbill male in Mangaon showing red iris and black on underside of casque
Great hornbill eating a fledgling bird
A female great hornbill carries food (fruit of Myristica beddomei) in her beak to feed the chick that is still inside the tree cavity nest
A female great hornbill (above) with a male (below) in Nelliyampathy
During the breeding season (January to April[7]) 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.[29] They prefer mature forests for nesting. Large, tall and old trees, particularly emergents that rise above the canopy, seem to be preferred for nesting.[30][31] 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.[32]
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.[6][33][34] 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.[29] Once the female emerges from the nest, the chicks seal it again.[7]
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.[35]
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.[13]
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.[1] 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.[13] Declines in population have been noted in many areas such as Cambodia.[36]
Tribesmen in parts of northeastern India use the feathers for head-dresses, and the skulls are often worn as decorations.[37] [38] 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.[39]
The great hornbill is listed in CITES Appendix I. It has been listed as Vulnerable on the IUCN Red List since 2018.[1] Conservation programmes have attempted to provide tribes with feathers from captive hornbills and ceramic casques to substitute for natural ones.[40]
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.[41][42][43][44]
Captive great hornbills eat fruits and meat, a healthy diet consisting mostly of fruit and some source of protein. A few have been tamed in captivity but their behaviour in captivity is described as highly strung. Captive specimens bask in the sun with outstretched wings.[45]
The great hornbill is called homrai in Nepal and banrao in Mussoorie, both meaning "King of the Jungle".[46] It is the official state bird of the Indian states of Kerala and Arunachal Pradesh.[47]
A great hornbill named William was the model for the logo of the Bombay Natural History Society and the name of the society's building. Norman Kinnear described William as follows in the obituary of Walter Samuel Millard:[48]
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.[49][50]
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.
