UPSC Relevance: GS Paper III – Environment and Biodiversity; Wildlife Conservation; Species Reintroduction; Protected Areas
Prelims Focus: Indian Grey Hornbill, Great Hornbill, Gir National Park, IUCN status and ecological role of hornbills

Why in the News?

The Indian Grey Hornbill has successfully re-established itself in Gujarat’s Gir landscape after disappearing from the region around the 1950s–60s. Birds reintroduced by the Gujarat Forest Department have established territories, adapted to their habitat and produced offspring.

The programme released 40 hornbills in two phases—28 birds during 2021–22 and another 12 in 2023. Eleven males were fitted with satellite transmitters to monitor their movement, habitat use and breeding behaviour. The birds were sourced from healthy populations in Gujarat’s Aravalli forests after assessments confirmed that Gir offered suitable ecological conditions.

The development is significant because the birth of offspring in the wild is an important indicator that a reintroduced population is progressing towards becoming self-sustaining.

About the Indian Grey Hornbill

The Indian Grey Hornbill (Ocyceros birostris) is a medium-sized arboreal bird belonging to the family Bucerotidae. It is among the most widespread and adaptable hornbill species of the Indian subcontinent.

It is also the state bird of the Union Territory of Chandigarh.

Distribution

The species is native to the Indian subcontinent and occurs across:

• India
• Pakistan
• Nepal
• Bangladesh

Within India, it is widely distributed in the plains and lower hills. Unlike several hornbill species that depend on dense evergreen forests, the Indian Grey Hornbill can survive in human-modified landscapes.

Habitat

It inhabits:

• Open deciduous forests
• Thorn and scrub forests
• Riparian woodlands
• Agricultural landscapes
• Rural settlements
• Urban parks and avenue plantations

Its survival depends significantly on the availability of mature trees that provide fruits and natural cavities for nesting.

Conservation status

Although classified as Least Concern, local populations can disappear because of the removal of mature trees, habitat fragmentation and the loss of nesting cavities. The earlier disappearance of the species from Gir demonstrates that a favourable global status does not necessarily guarantee local ecological security.

Important Characteristics

1. Distinctive appearance

The bird is approximately 60 centimetres long and possesses:

• Greyish-brown plumage
• A pale eyebrow or superciliary stripe
• A long tail tipped with white
• A large, curved bill
• A prominent casque above the bill

The casque of the female is generally smaller and more pointed than that of the male.

2. Arboreal nature

Indian Grey Hornbills spend most of their time on trees. They move between fruit-bearing trees and rarely descend to the ground.

3. Unique flight and calls

They fly through a combination of powerful wing flaps and gliding. Their presence can often be identified through loud, squealing or cascading calls.

4. Monogamous behaviour

The species is generally monogamous and is commonly observed in pairs or small family groups.

5. Omnivorous diet

The Indian Grey Hornbill is primarily frugivorous but also consumes:

• Insects: Lizards: Scorpions:Small rodents: Eggs and nestlings of smaller birds

Ecological Importance

Farmers of the Forest

Hornbills consume a wide variety of fruits and disperse their seeds over considerable distances. Because many seeds pass through their digestive system intact, hornbills contribute to:

• Natural forest regeneration
• Maintenance of plant diversity
• Colonisation of degraded forest patches
• Gene flow among plant populations
• Restoration of ecological connectivity

The decline of hornbills can consequently affect the regeneration of large-seeded forest trees.

Indian Grey Hornbill and Great Hornbill: Comparison