Green Imperial Pigeon (Ducula aenea) – A Comprehensive Study

Taxonomy & Classification

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

The Green Imperial Pigeon (Ducula aenea) is one of the largest arboreal pigeons, known for its majestic green plumage and strong, swift flight. It is widely distributed across South and Southeast Asia, particularly in tropical forests and mangrove ecosystems.

Morphology & Physical Description

• Size: 39–45 cm in length
• Wingspan: 45–50 cm
• Weight: 350–600 grams
• Plumage:
  • Head and Neck: Pale greyish-white with a soft, velvety texture.
  • Back and Wings: Glossy metallic green, giving the bird its name.
  • Underparts: Light gray to buff-colored.
  • Tail: Dark greenish-black, broad, and slightly rounded.
• Beak: Short, pale bluish-grey, with a slightly curved tip.
• Legs & Feet: Short and strong, purplish-red, adapted for gripping branches.
• Eyes: Dark red or brown, surrounded by a thin blue eye-ring.

Habitat & Distribution

The Green Imperial Pigeon thrives in a variety of forested habitats, including:

• Tropical and subtropical rainforests
• Mangrove forests and coastal woodlands
• Evergreen and deciduous forests up to 1500 meters elevation

Presence in the Sundarban

The Sundarban, the largest tidal halophytic mangrove forest, provides an ideal habitat for the Green Imperial Pigeon due to its:

• Dense canopy cover of trees like Sundari (Heritiera fomes) and Gewa (Excoecaria agallocha).
• Abundance of fruits, particularly figs and berries, which form a major part of its diet.
• Undisturbed nesting sites in tall trees.

In the Sundarban Biosphere Reserve, the Green Imperial Pigeon is a resident species, commonly sighted in:

• Khulna and Satkhira regions of Bangladesh Sundarban
• Sundarban Tiger Reserve, West Bengal, India
• Riverine islands and dense mangrove patches

This species plays a vital role in seed dispersal, aiding in the regeneration of the Sundarban’s mangrove vegetation.

Feeding Behavior & Diet

The Green Imperial Pigeon is a frugivorous bird, primarily feeding on:

• Wild figs, berries, and drupes
• Mangoes, guavas, and other soft fruits
• Occasionally, flower buds and young leaves

Foraging Strategy

• Primarily arboreal, feeding at the canopy level.
• Uses its strong beak to pluck fruits and swallow them whole.
• A key seed disperser, aiding in forest regeneration.

Breeding & Nesting

• Breeding Season: March to June, sometimes extending into the monsoon period.
• Nest Sites: Prefers high branches in tall trees, well-hidden among dense foliage.
• Nest Structure: Simple platform of twigs and leaves, loosely built.
• Eggs: Lays one or two white eggs per clutch.
• Parental Care: Both male and female share incubation (18–20 days) and chick-rearing duties.

Vocalization & Communication

The Green Imperial Pigeon has a distinct call:

• A deep, resonating “whoo-whooo” or “hoo-hoo-hoo” sound.
• Calls are loud and repetitive, used for territorial signaling and mate attraction.
• Often heard at dawn and dusk, echoing across the forest canopy.

Special Adaptations

1. Cryptic Plumage: The green metallic feathers blend seamlessly with foliage, offering natural camouflage.
2. Strong Flight Muscles: Adapted for swift, long-distance flights between feeding and nesting sites.
3. Seed Dispersal Ability: Swallows fruits whole, later excreting seeds intact, promoting forest regeneration.
4. Mangrove Adaptation: Can thrive in saline, humid conditions of mangrove forests like the Sundarban.

Threats & Conservation Status

• Habitat destruction due to deforestation and urbanization.
• Illegal hunting and poaching for its meat and feathers.
• Climate change effects, particularly cyclones and rising sea levels, affecting mangrove forests.
• Competition for food with invasive bird species.

IUCN Status: Least Concern (LC)

Despite threats, the Green Imperial Pigeon population remains stable due to its wide distribution and adaptability. Strict conservation efforts in the Sundarban are essential for its long-term survival.

Ecological Importance in the Sundarban

• A major frugivore, contributing to the natural seed dispersal process in the Sundarban mangrove ecosystem.
• Acts as a bio-indicator of forest health, as its presence signals a rich, undisturbed habitat.
• Plays a role in maintaining ecological balance, coexisting with other frugivorous species.

Conclusion

The Green Imperial Pigeon (Ducula aenea) is a crucial resident bird of the Sundarban, thriving in its dense, fruit-rich mangrove forests. Its vibrant green plumage, strong flight, and ecological importance make it a keystone species for forest regeneration. Protecting mangrove habitats will ensure its continued presence in the fragile Sundarban ecosystem.