The great hornbill (Buceros bicornis) is a large bird found in the forests of South and Southeast Asia. With its impressive size, unique casque, and loud call, the great hornbill is a distinctive species that plays an important role in forest ecosystems. However, like many other wildlife species, the great hornbill faces a number of threats that have raised concerns about its conservation status.
Quick Facts on the Great Hornbill
Here are some key facts about the great hornbill:
- Scientific name: Buceros bicornis
- Average length: 95-130 cm
- Average weight: 2.5-4 kg
- Lifespan: Up to 50 years
- Diet: Omnivorous – eats fruits, insects, small reptiles and mammals
- Range: India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, Indonesia
- Habitat: Tropical and subtropical moist broadleaf forests
- Status: Vulnerable to extinction
Is the Great Hornbill Endangered?
The great hornbill is currently classified as Vulnerable on the IUCN Red List of Threatened Species. This means that while it is not endangered yet, it faces a high risk of endangerment in the wild in the medium-term future.
The main threats facing the great hornbill that have contributed to its Vulnerable status include:
- Habitat loss due to deforestation
- Hunting for bushmeat and traditional medicine
- Poaching of chicks for the pet trade
- Climate change impacts
These threats have led to population declines across the hornbill’s range, though loss of forest habitat is the most severe threat. Most remaining hornbill populations are small and fragmented due to deforestation.
Population Trends
The global population size of the great hornbill has not been precisely quantified but is estimated to number 50,000-150,000 mature individuals. Population trends have been difficult to gauge on a global scale but surveys in Southeast Asia have shown declines of 30-90% over the past 40 years in many areas.
For example, in Thailand great hornbill numbers dropped from 100-200 pairs per square kilometer of forest in the 1960s to less than 10 pairs per square kilometer in recent surveys. Similar declines have been noted in Malaysia and Indonesia.
Conservation Actions
Some conservation actions are being taken to protect great hornbills, including:
- Legal protection in most range countries
- Captive breeding programs
- Habitat protection in protected areas
- Reintroduction programs in Singapore, Indonesia, and Thailand
- Community-based conservation programs engaging local people
However, habitat loss and hunting pressures continue to threaten populations. Stronger protection and expanded habitat conservation will be needed to stabilize numbers.
Great Hornbill Description
The great hornbill is among the largest hornbill species and one of the most impressive-looking birds in Asia. It has some key identifying features:
- Size: 95-130 cm long with a wingspan around 150 cm
- Weight: 2.5-4 kg
- Plumage: Mainly black with a white tail, neck, throat, and belly
- Casque: Large golden yellow casque on top of bill
- Bill: Massive yellow and black bill that curves downward
- Eyes: Red iris and pale blue orbital skin
- Legs: Thick and grey
Males and females look similar but females are slightly smaller. Juveniles have a smaller casque and darker orbital skin. The casque’s shape and size helps distinguish the great hornbill from other Asian hornbills.
Call
Great hornbills have a loud, reverberating call that can be heard up to 5 km away. Their call consists of a series of 2-5 loud “tok” notes that sound like a hammer hitting wood. This territorial call announces the hornbill’s presence and pairs may call together as a duet.
Great Hornbill Behavior and Ecology
Here are some key facts about great hornbill behavior and ecology:
- Diet: Omnivorous; feeds on fruits, insects, small vertebrates
- Foraging: Feeds by hopping along branches and gathering fruit; also hawks insects
- Breeding: Nests in large tree cavities sealed with mud and saliva
- Chick rearing: Female seals self in nest cavity, relying on male to feed her
- Territory size: Defends a territory of 2-12 square km
- Forest dependence: Relies on large old-growth trees for nesting and foraging
- Role in ecosystem: Important seed disperser for forest trees
Some key behavioral notes:
- Highly territorial birds that defend a home range year-round
- Nest in large emergent trees, relying on big cavities for breeding
- Unusual breeding strategy with female sealing herself into nest cavity
- Male feeds female through a small slit during 3-4 month incubation period
- Long lived, with lifespans exceeding 50 years in captivity
Diet and Foraging
Great hornbills have an omnivorous diet consisting mainly of fruit along with insects, smaller vertebrates and other prey. Figs are a preferred food source. They forage alone or in pairs, moving between fruit trees and scanning for ripe figs and other fruits. From a high perch, they may hawk passing insects.
Breeding
One of the great hornbill’s most fascinating behaviors is their unique breeding strategy. They nest in large tree cavities, with females sealing themselves inside using mud, droppings and food remains. Only a small slit is left through which the male passes food. Inside, the female lays eggs, incubates them and cares for the chicks without leaving the nest for 3-4 months! Meanwhile the male feeds her and the chicks through the slit.
Great Hornbill Habitat
Great hornbills inhabit tropical moist forests across their range in South and Southeast Asia. Some details about great hornbill habitat preferences:
- Forest type: Mainly found in lowland and hill evergreen forests
- Elevation: Up to 1500 m, occasionally higher
- Landscape: Interior and edges of mature forest
- Trees: Depends on large emergent trees for nesting
- Range: Fragmented distribution from India to Indonesia
- Strongholds: Western Ghats (India), forests in Thailand and Malaysia
Within these tropical forests, great hornbills require:
- Large cavities in big old trees for nesting
- Adequate food resources like fig trees
- High, open perches for observing territory
They may disperse into open woodlands and orchards nearby when feeding but require intact forest for breeding. Loss of nest site availability limits populations.
Range and Distribution
Here is a overview of the great hornbill’s distribution across South and Southeast Asia:
- Indian subcontinent: India, Nepal, Bhutan, Bangladesh
- Southeast Asia: Myanmar, Thailand, Laos, Vietnam, Cambodia, Malaysia, Indonesia
- Fragmented, declining distribution across this range
- Possibly extinct in Java; Critically Endangered in Vietnam
Strongholds likely remain in parts of Northeast India, Myanmar, Thailand and Malaysia where significant intact forests persist. However, populations are increasingly fragmented and isolated as deforestation advances across the hornbill’s range.
Threats to Great Hornbills
Great hornbills face a variety of anthropogenic threats that have contributed to population declines and their Vulnerable conservation status. Major threats include:
Habitat Loss
The most severe threat is accelerating deforestation across the hornbill’s range. Logging, agricultural expansion and development have led to widespread habitat degradation and loss:
- Declining nest site availability as large old trees are removed
- Reduced food availability due to forest fragmentation
- Increased nest predation and competition in degraded habitats
Forest loss and fragmentation has been directly correlated with hornbill disappearance in many areas. Continued deforestation could lead to extinction in certain regions.
Hunting and Poaching
Additional threats come from hunting and poaching pressure:
- Hunted for bushmeat and traditional medicine in some areas
- Poaching of chicks for the pet trade occurs in parts of range
- Killing of adults at nests to harvest casques and feathers
- Casques used locally for decorative carvings and ornaments
These pressures add to mortality rates and along with habitat loss have devastated some populations. Hornbills are also vulnerable to accidental poisoning from pesticides in agricultural areas.
Climate Change Impacts
Climate change poses a potential long-term threat by affecting forest habitats. Impacts may include:
- Increased drought stress on fruiting trees
- Possible upward elevation shifts in habitat over time
- Increased vulnerability to storms and wildfires
These effects could influence food supplies and nest site availability. The full impacts remain uncertain but climate shifts may exacerbate other threats.
Great Hornbill Conservation
To protect remaining great hornbill populations, increased conservation efforts are needed to address threats. Some recommended actions include:
- Expand protected forest habitat and improve enforcement against deforestation and poaching
- Increased legal protections in countries where hunting and trade continue
- Engage local communities in ecotourism and sustainable use programs
- Restore habitats and reintroduce captive-bred birds where feasible
- Monitor populations and habitat trends to target conservation priorities
International cooperation and support for conservation programs across the great hornbill’s range will be essential to ensure the species persists and recovers in the wild. Protecting intact, mature forests will be key. With adequate habitat, this unique bird can recover from low levels but their survival depends on expanded conservation action.
Conclusion
The great hornbill is currently threatened by a variety of human pressures across its Asian range. While not yet endangered, the species is facing concerning declines from habitat loss, hunting and climate change impacts. Improved legal protections, forest conservation initiatives and community engagement offer hope for stabilizing populations. But without significant conservation intervention, the outlook for the great hornbill may worsen as development expands across the region. Timely action to conserve remaining intact forests and restore degraded habitats can help ensure this iconic bird continues to grace Asia’s forests well into the future.