Pied Imperial Pigeon (Ducula bicolor) – A Comprehensive Study

Taxonomy & Classification

• Kingdom: Animalia
• Phylum: Chordata
• Class: Aves
• Order: Columbiformes
• Family: Columbidae
• Genus: Ducula
• Species: Ducula bicolor

The Pied Imperial Pigeon (Ducula bicolor) is a large, arboreal pigeon belonging to the Columbidae family. This species is known for its striking white and black plumage and its affinity for coastal and island habitats. It is widely distributed across the Indian subcontinent, Southeast Asia, and Australia.

Morphology & Physical Description

• Size: 37–44 cm in length
• Wingspan: 45–55 cm
• Weight: 350–600 grams
• Plumage: Mostly white with black flight feathers and tail tips, giving it a distinct appearance.
• Beak: Slender, slightly curved, and pale bluish-grey.
• Eyes: Dark, with a yellowish orbital ring.
• Legs & Feet: Short, pinkish to purplish, adapted for perching in trees.
• Tail: Medium-length with black tips, used for stability in flight.

Sexual Dimorphism

There is little visible difference between males and females, but males tend to be slightly larger with more robust bills. Juveniles appear similar to adults but with a duller, more buff-colored plumage.

Habitat & Distribution

The Pied Imperial Pigeon prefers warm, coastal, and tropical habitats, including:

• Mangroves and riverine forests
• Coastal islands and estuaries
• Tall evergreen and mixed deciduous forests

This pigeon species is found across:

• Southeast Asia (India, Bangladesh, Myanmar, Thailand, Indonesia, and the Philippines)
• Northern Australia and the Pacific Islands
• Indian Ocean islands, including the Andaman & Nicobar Islands

Presence in the Sundarban

The Sundarban, with its vast expanse of mangrove forests and estuarine islands, provides an ideal habitat for the Pied Imperial Pigeon. This species is primarily found:

• Perched on tall mangrove trees, especially species like Sundari (Heritiera fomes) and Goran (Ceriops decandra)
• In mixed-species flocks near estuarine water bodies
• During seasonal movements between Bangladesh and India’s Sundarban region

Though not extremely common, Pied Imperial Pigeons are occasionally seen in the Sundarban Biosphere Reserve, particularly in less disturbed and isolated mangrove pockets.

Diet & Foraging Behavior

The Pied Imperial Pigeon is frugivorous, with a strong preference for:

• Figs (Ficus species)
• Fruits of mangrove trees and coastal vegetation
• Berries, drupes, and seeds

Foraging Strategy

• Feeds high in the canopy, plucking fruits directly from branches.
• Can swallow large fruits whole, later regurgitating seeds, which aids in seed dispersal.
• Occasionally supplements its diet with small insects and leaves.

Breeding & Nesting

• Breeding Season: Typically from March to August, depending on location.
• Nesting Sites: Prefers high branches in dense foliage, often choosing mangrove trees.
• Nest Type: A simple, loosely built platform of twigs, usually well-hidden.
• Eggs: Typically one white egg per clutch.
• Incubation: Lasts around 26–28 days, with both parents sharing duties.

Vocalization & Communication

• Low, repetitive “coo-coo” calls, often heard at dawn and dusk.
• Soft murmuring sounds during courtship and social interactions.

Special Adaptations

1. Strong Flight Capability: Can travel long distances between feeding and roosting sites.
2. Seed Dispersal Role: A crucial seed disperser for mangrove and coastal forests, helping in forest regeneration.
3. Camouflaged Nesting: White plumage blends with sunlight filtering through treetops, reducing predation risk.
4. Resistance to Saline Conditions: Thrives in coastal and mangrove environments, unlike most pigeon species.

Threats & Conservation Status

• Habitat Loss due to deforestation and urban expansion
• Hunting & Poaching in certain regions for food and the pet trade
• Climate Change Effects, especially coastal erosion and habitat degradation
• Predation by raptors and invasive species like snakes and monitor lizards

IUCN Status: Least Concern (LC)

Despite localized threats, the Pied Imperial Pigeon has a stable global population. However, conservation of mangrove forests in the Sundarban is crucial for sustaining its presence.

Significance in the Sundarban Ecosystem

• Acts as an important seed disperser, ensuring forest regeneration.
• Provides food for predators such as hawks and eagles, maintaining ecological balance.
• Indicator species for mangrove health and biodiversity richness.

Conclusion

The Pied Imperial Pigeon (Ducula bicolor) is a magnificent frugivorous bird, well-adapted to coastal and mangrove ecosystems like the Sundarban. Though not a highly common species in this region, its presence highlights the rich avian diversity of the Sundarban Biosphere Reserve. Protecting mangrove forests and limiting human disturbance are essential to ensuring its continued survival in this unique ecosystem.