Great Hornbill

The great hornbill is a large bird, 95–130 cm long, with a 152 cm wingspan and a weight of 2 to 4 kg 4.4 to 8.8 lb. The average weight

of 7 males was 3 kg 6.6 lb whereas that of 3 females was 2.59 kg 5.7 lb.It is the heaviest, but not the longest, Asian hornbill falling

second to the similarly weighted helmeted hornbill due to the latters extremely long tail feathers.Females are smaller than males and h

ave 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 view

ed from the front, and the top is concave, with two ridges along the sides that form points in the front, whence the Latin species ep

ithet 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 believed to be the result of sexual selection. Male hornbills

have been known to indulge in aerial casque butting, with birds striking each other in flight.[5] The male spreads the preen gland se

cretion, which is yellow, onto the primary feathers and bill to give them the bright yellow colour.The commissure of the beak is

black and has a serrated edge which becomes worn with age.

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.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.The casque is hollow and serves

no known purpose, although it is believed to be the result of sexual selection. Male hornbills have been known to indulge in aerial cas

que butting, with birds striking each other in flight.The male spreads the preen gland secretion, which is yellow, onto the primary feat

hers and bill to give them the bright yellow colour.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.

They sometimes fly at great height over forests.