The Hornbills of Borneo
- devanandpaul
- Oct 8
- 5 min read
Updated: 6 days ago
In the quiet mornings of Borneo’s rainforests, you might hear a steady whoosh-whoosh in the air, like the beat of a hidden drum. Look up, and you will see hornbills, the heartbeat of Bornean forests, zipping through the mist with their powerful wings. For a moment, you wonder whether you have slipped into another era—hornbills look as though they belong to the prehistoric world. In a way, they do. Fossil records show hornbill-like birds existed around 15 million years ago.
Here I share with you some information about the hornbills of Borneo, their importance in the forest ecosystem, and the urgent need to protect both these birds and their home.
Lords of the Canopy
Hornbills are big birds, some nearly the size of a small eagle. Most feature black-and-white plumage, but it is their curved bills and casques that define them. The casque, a hollow helmet on top of the bill, may amplify calls, strengthen the bill, and make courtship displays more impressive.
Borneo is home to eight species of hornbills, and all of them can be found in Sabah (a province in Malaysian Borneo). Each has its own temperament, rhythm, and voice in the chorus of the forest.
White-crowned hornbill
The white-crowned hornbill is an unusual-looking bird with a fluffy white crest and a long white tail. Unusually carnivorous, it prefers quiet riverine forests, where small family groups of four to six hunt insects and small prey together. It is a cooperative breeder—the extended family helps with rearing the young. Its gentle pigeon-like kuk kuk kuk calls are carried through the forest.
Bushy-crested hornbill
In contrast, the bushy-crested hornbill is one of the most common and noisy species. Found throughout Borneo’s lowlands and hills, in both logged and virgin forests, It lives in boisterous flocks of 8 to 12. Also a cooperative breeder, it is plain and medium-sized. Its shrill yelps and group calls can fill entire valleys, making it unmistakable to identify.
Oriental pied hornbill
The oriental pied hornbill is highly adaptable, thriving in coastal forests, river edges, and even near villages. It often moves in noisy flocks but nests alone during breeding. Its white belly and black markings on the bill distinguish it from the black hornbill, and its cackling calls make it a familiar garden visitor in places like Sepilok.
Asian black hornbill
The Asian black hornbill—similar in size to the pied hornbill but preferring primary lowlands and swampy forests—often follows gibbons to catch stirred-up insects. It is usually seen in pairs. Its harsh, squealing calls are often heard even before the bird appears. Males have a large white bill; females, darker, with reddish skin around the eye. Also, males have a larger and more projecting casque, compared with the blunter one in females.
Wrinkled hornbill
In the stillness of Borneo’s peat swamp forests, the brightly coloured wrinkled hornbill moves wherever figs are ripe. Smaller than its relatives, with a yellowish tail and a throat pouch, it is a quiet, nomadic species, scarce yet locally common in Sarawak (another province in Malaysian Borneo) and Brunei (an independent sultanate within Borneo). Males have a yellow bill and a red casque; in females, both the bill and the casque are yellow.
Wreathed hornbill
The wreathed hornbill sweeps high above the canopy in semi-nomadic flocks. Males have yellow throats; females, blue; young, green. Its doglike barks are not melodic but help maintain group cohesion as they roam from swamps to hill forests to even Mount Kinabalu, the highest mountain in Malaysia and Maritime Southeast Asia, at 4095 metres.
Rhinoceros hornbill
The rhinoceros hornbill is a striking bird with black plumage, a white tail with a black band, and a bright orange casque, the colour coming from preen oil (secreted by the preen gland at the base of the tail). It is seen in pairs or large nomadic flocks, and its loud honks and cackles resonate through the forest.
Helmeted hornbill
The helmeted hornbill is a very large bird with a solid ivory casque, used in aerial clashes. Its long tail feathers trail like banners, and its call, a rapid series of hollow notes, echoes across the forest. Threatened by illegal hunting for its ‘red ivory’, it is one of Borneo’s most endangered birds and is now very rare.
Gardeners of the Rainforest
Hornbills are vital to Borneo’s ecology. They feed on figs and disperse the intact seeds across the forest, ensuring new trees grow where none existed. They also eat insects, lizards, rodents, and small mammals, maintaining balance in the ecosystem.
Nesting Behaviour
Hornbills have a unique nesting behaviour: Females seal themselves for months in tree hollows with a mixture of clay and droppings, leaving only a narrow slit for the males to feed them (and later the fledglings) and, in cooperative species (white-crowned and bushy-crested), for the group to assist in breeding. Their life cycle is linked to forest health, as their breeding depends on fruit abundance.
Hornbills in Local Culture
Hornbills hold deep cultural significance in Borneo. The rhinoceros hornbill is sacred to Dayak communities, appearing on Sarawak’s state emblem. Its feathers adorn ceremonial headdresses. And in Iban culture, hornbills symbolize strength and courage, and hold spiritual importance.
Where to See Hornbills in Sabah, Borneo
You can spot hornbills in the following sites:
• Kinabatangan River: Morning and evening boat cruises provide plenty of opportunities to spot hornbills flying across the river or perched on riverside trees.
• Danum Valley Conservation Area: All eight hornbill species can be spotted in this pristine rainforest.
• Tabin Wildlife Reserve: Large forests in this reserve support healthy hornbill populations.
• Mount Kinabalu National Park: This UNESCO World Heritage Site provides opportunities to see high-altitude hornbill species.
Hornbills and the Future of Borneo’s Forests
Borneo’s lowland forests host all eight hornbill species, but logging, hunting, and fragmenting of forests for farming, road construction, and urbanization have reduced their numbers. Hornbills are ecosystem health indicators: Where they thrive, fig trees, orangutans, gibbons thrive, and there is rich biodiversity; where they are endangered, there is loss of biodiversity.
Protected areas like Sepilok (60 km2) are large enough for smaller hornbills but insufficient for wide-ranging species (those that occupy a very large geographic area or move across vast distances). Ecologists warn that without habitat restoration, species like the wreathed, wrinkled, helmeted, and rhinoceros hornbills may vanish.
Worldwide, hornbill populations are falling. Conservation projects in Philippines, Thailand, South Africa, and Singapore depend on preserving suitable habitats. Hornbills require abundant fruit trees, especially figs, to thrive.
Closing Thoughts
Seeing hornbills in their natural world has taught me a profound truth: to protect the hornbills is to protect the rainforest itself.
Through this blog, I hope to spark curiosity, respect, and action. If even a few are inspired to protect these incredible birds, their echoes will continue to fill Borneo’s skies for generations. As Baba Dioum, a Senegalese conservationist, said:
‘In the end, we will conserve only what we love, we will love only what we understand, and we will understand only what we are taught.’
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Your photos are stunning in clarity. The accompanying text is equally lucid and passionate about conservation of the biodiversity. Great job.
Beautifully written! I love how you highlighted Malaysia’s hornbills as both cultural icons and vital parts of the ecosystem. It’s inspiring to see awareness being raised for their conservation.