Save hornbills, for they are the gardeners of tropical forests: Study

The researchers, from Nature Conservation Foundation (NCF), Mysuru and Centre for Ecological Sciences, Indian Institute of Science, Bengaluru conducted the study on the Hornbill Plateau in Namdapha.

• Scientists from two organisations studied how fruiting plants and hornbills influenced each other’s distribution in the Namdapha Tiger Reserve.
• The reserve, located in Arunachal Pradesh, is one of India’s most biodiverse protected areas. It is home to five of India’s nine species of hornbills.
• They conducted the study across twenty-four 1-hectare patches on the Hornbill Plateau.
• They counted 815 hornbills, 157 hornbill food plants, 946 seeds that were dispersed in 1,600 one-metre patches and 5,173 regenerating saplings of multiple large-seeded hornbill food plant species.

About Hornbills

• Hornbills (Bucerotidae) are a family of birds found in tropical and subtropical Africa, Asia and Melanesia.
• They are characterized by a long, down-curved bill which is frequently brightly colored and sometimes has a casque on the upper mandible.
• They are diurnal, generally travelling in pairs or small family groups
• They are omnivorous birds, eating fruit, insects and small animals.

Hornbill Species in India

• There are approximately 60 hornbill species world-over of which nine reside in India.
• Of the nine species, those found in the Western Ghats include:
  • The Great Hornbill.
    • The great hornbill (Buceros bicornis) also known as the great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family.
    • A large majority of their population is found in India with a significant proportion in the Western Ghats and the Nilgiris.
    • IUCN status: Vulnerable
    • Indian Protected Areas: the Anamalai Tiger Reserve and Dandeli National Park (Western Ghats), Corbett Tiger Reserve (north India) and Kaziranga, Pakke, Namdapha and Manas (north-east India).
  • The Malabar Grey Hornbill
    • The Malabar grey hornbill (Ocyceros griseus) is a hornbill endemic to the Western Ghats and associated hills of southern India.
    • They are found mainly in dense forest and around rubber, arecanut or coffee plantations.
    • IUCN status : Vulnerable
    • Indian Protected Areas : Anamalai Tiger Reserve, Tamil Nadu, Periyar and Parambikulam Tiger Reserve, Kerala
  • Malabar Pied Hornbill
    • The Malabar pied hornbill is a common resident breeder in India and Sri Lanka. Its habitat is evergreen and moist deciduous forests, often near human settlements.
    • IUCN Status : Near Threatened
    • Indian Protected Areas : Bandipur, Nagarahole, Dandeli in Karnataka, Satpura Tiger Reserve, Madhya Pradesh.
  • The other Hornbill species in India include:
    • Indian Grey Hornbill
      • The Indian Grey Hornbill (Ocyceros birostris) is a fairly common hornbill species found only in the Indian subcontinent.
      • They are cavity nesters, making use of big hollows in trees as nesting sites.
      • IUCN status : Least Concern
    • Oriental Pied Hornbill
      • The oriental pied hornbill is found in the Indian Subcontinent and Southeast Asia, ranging across Bangladesh, Bhutan, Brunei, Cambodia, Eastern and Northern India, Indonesia, Laos, North peninsular Malaysia, Myanmar, Nepal, Singapore, Thailand, Tibet, Vietnam and the Sunda shelf islands.
      • Its natural habitat is subtropical or tropical moist lowland forests.
      • IUCN Status : Least Concern
      • Indian Protected Areas: Rajaji National Park and Corbett Tiger Reserve in north India and in Nameri and Pakke Tiger Reserves and several other Protected Areas in north-east India, also common in forests outside Protected Areas.
    • Wreathed Hornbill
      • The wreathed hornbill (Rhyticeros undulatus), also known as the bar-pouched wreathed hornbill, is a species of hornbill native to forests in northeast India, Bhutan, mainland Southeast Asia and the Greater Sundas in Indonesia.
      • IUCN status : Vulnerable
      • Indian Protected Areas : Manas, Nameri, Pakke and Namdapha Tiger Reserves.
    • Rufous-necked hornbill
      • The rufous-necked hornbill (Aceros nipalensis) is a species of hornbill in Bhutan, northeastern India, especially in Arunachal Pradesh, Indian Subcontinent and Southeast Asia.
      • It is locally extinct in Nepal due to hunting and significant loss of habitat.
      • IUCN status: Vulnerable
      • Indian Protected Areas : Namdapha Tiger Reserve, Eaglenest Wildlife Sanctuary, Pakke Tiger Reserve, Arunachal Pradesh, Mahananda Wildlife Sanctuary and Neora Valley National Park in northern West Bengal.
    • Narcondam Hornbill
      • It is endemic to the Indian island of Narcondam in the Andamans.
      • The Narcondam hornbill has the smallest home range out of all the species of Asian hornbills.
      • IUCN Status : Vulnerable
    • Austen’s Brown Hornbill
      • Austen's brown hornbill (Anorrhinus austeni) is a species of hornbill found in forests from northeastern India and south to Vietnam and northern Thailand.
      • IUCN Status : Near Threatened
      • Indian Protected Areas: Namdapha Tiger Reserve.

Threats to Hornbills in India

• The hornbills face different threats across the country depending upon the culture, governance and densities of the human population.
• Hunting and logging are probably the most relevant threats in north-east India where law enforcement is poor and strong cultural practices are attached to hornbills.
  • For example, the Great Hornbill and Rufous necked Hornbills are hunted for their spectacular feathers, casque and beaks to adorn the headdresses and their meat is believed to have medicinal value.
• Another important threat to the hornbill is loss of habitat and fragmentation which is accelerating in the north-east regions.
  • With traditional shifting cultivation practices being replaced by permanent cash crop plantations, particularly in community-owned lands, leads to permanent loss in natural habitats and little scope for vegetation recovery.
  • Also illegal occupation of land due to improper settlement of land rights or poor enforcement by the forest department, along with burgeoning human population pose significant threats to lowland forest habitats across the hornbill habitat.
• As frugivores, the hornbills need a large forest with ficus trees. However, logging of these trees as well as tree species that provide nesting have led to significant reduction in their population.

Hornbill Conservation in India

• A citizen-science based initiative, Hornbill Watch which was launched by Nature Conservation Foundation (NCF) and Conservation India (CI) in 2014 records the number of sightings of different hornbill species across India.
• Community-based conservation of Hornbills
  • The Nyishi tribe of Western Arunachal Pradesh could be taken as an example for their recent significant contribution in the effort to save these majestic birds from extinction.
  • The community has been closely working with Nature Conservation Foundation (NCF) in the surrounding areas of Pakke Wildlife Sanctuary and Tiger Reserve which is a crucial nesting habitat for hornbills.
  • They adopt hornbill nests and help protect them under the Hornbill Nest Adoption Programme and also ensure conservation of hornbill habitats outside the protected area of the park.
• Hornbills are hunted for their casques — upper beak — and feathers for adorning headgear. A conservation programme promoting the use of fibre-glass beaks for headgear instead of real hornbill casques has helped reduce some threat to it.

Hornbill: Gardeners of Tropical Forests

• The conservation of hornbills is of prime importance since they have a symbiotic relationship with several canopy trees in tropical forests. They are attracted to such trees for food and in turn, they scatter their seeds, creating orchards.
• Hornbills were among the very few birds that could feed on fruits with large seeds, regurgitate and disperse the undamaged seeds away from the mother plant.
• Hornbills as Seed dispersers:
  • The Indian Grey Hornbill plays an essential role in the ecosystem as prime dispersers of seeds. In cities, we may find them feeding on fig trees like banyan, Goolar (a variety of fig), usually choosing old tall dense trees for nesting.