Asian Koel (Eudynamys scolopaceus) – A Comprehensive Study

Taxonomy & Classification

• Kingdom: Animalia
• Phylum: Chordata
• Class: Aves
• Order: Cuculiformes
• Family: Cuculidae
• Genus: Eudynamys
• Species: Eudynamys scolopaceus

The Asian Koel (Eudynamys scolopaceus) is a large cuckoo species, widely known for its melodious and loud calls, especially during the breeding season. It is a brood parasite, meaning it lays its eggs in the nests of other bird species, particularly crows. This bird plays an important ecological role in seed dispersal, as it primarily feeds on fruits.

Morphology & Physical Description

The Asian Koel exhibits sexual dimorphism, meaning males and females have distinct appearances.

Male Asian Koel

• Plumage: Entirely glossy blue-black with a metallic sheen.
• Eyes: Deep red, giving an intense look.
• Beak: Pale greenish or ivory-colored, slightly curved.
• Legs & Feet: Greyish and strong, adapted for perching.
• Size: 39–46 cm in length.
• Wingspan: Approximately 46–50 cm.
• Weight: 190–327 grams.

Female Asian Koel

• Plumage: Brownish with heavy white streaks and spots on the back and wings.
• Underparts: White with dark brown barring.
• Eyes & Beak: Similar to the male, with red eyes and a pale beak.

Habitat & Distribution

The Asian Koel is a highly adaptable bird, found in a variety of habitats across South and Southeast Asia, including:

• Forests, mangroves, and riverine areas
• Urban gardens, agricultural fields, and orchards
• Tropical and subtropical woodlands
• Coastal and estuarine ecosystems

Presence in the Sundarban

The Sundarban, with its dense mangrove forests, tidal waterways, and rich fruit-bearing trees, provides an ideal habitat for the Asian Koel. It is a common resident species in this region, found in:

• Mangrove fringes, where fruit-bearing trees like figs and berries grow.
• Near human settlements, as it thrives in semi-urban environments.
• Close to crow populations, since it parasitizes their nests for reproduction.

The Asian Koel is often heard in the Sundarban Biosphere Reserve, especially during the early morning and breeding season, when its distinctive call echoes through the forests.

Feeding Behavior & Diet

The Asian Koel is primarily frugivorous (fruit-eating) but is also known to consume insects and small invertebrates.

Primary Diet:

• Fruits (figs, berries, papaya, guava, and banyan fruits)
• Nectar from flowers
• Insects (caterpillars, beetles, and grasshoppers)
• Small lizards and eggs of other birds (occasionally)

Role in the Ecosystem:

• Seed Disperser: By consuming fruits and excreting seeds over large areas, the Asian Koel helps in the regeneration of mangrove and tropical trees.
• Population Regulator: As a brood parasite, it influences the breeding success of host birds like crows and mynas.

Breeding & Nesting Behavior

One of the most remarkable traits of the Asian Koel is its brood parasitism, meaning it does not build its own nest but instead lays its eggs in the nests of other bird species.

• Breeding Season: Typically March to August, coinciding with the breeding season of crows and mynas.
• Host Birds: Primarily House Crows (Corvus splendens) and Large-billed Crows (Corvus macrorhynchos).
• Egg Laying: The female lays one or two eggs in the host’s nest, often removing the host’s eggs to avoid detection.
• Incubation Period: Around 12–14 days (incubated by the host bird).
• Chick Behavior: The Koel chick hatches earlier than the host’s chicks, ensuring better survival as it monopolizes the food brought by the foster parents.

Vocalization & Communication

The Asian Koel is best known for its distinct, melodious call, which is most common during the breeding season.

• Male Call: A loud, repeated “koo-ooo” sound, often heard early in the morning and late in the evening.
• Female Call: A shrill “kik-kik-kik” sound, usually in response to the male.
• Alarm Calls: A harsh, rapid “kee-kee-kee” when threatened.

Special Adaptations

1. Brood Parasitism: The ability to lay eggs in other birds’ nests ensures reproductive success without parental care.
2. Mimicry of Host Eggs: The Koel’s eggs closely resemble those of crows, making detection difficult.
3. Excellent Vocal Abilities: Loud calls help in territory marking and mate attraction.
4. Seasonal Behavior: More vocal and visible during breeding but remains elusive during the non-breeding season.
5. Adaptive Diet: Can thrive in both natural and human-dominated landscapes, making it highly resilient.

Threats & Conservation Status

The Asian Koel is classified as Least Concern (LC) by the IUCN, due to its wide distribution and stable population. However, it faces some localized threats:

• Habitat destruction (deforestation, urbanization)
• Reduction of host bird populations due to environmental changes
• Pesticide contamination, affecting fruit availability

Conservation in the Sundarban

In the Sundarban, conservation efforts focused on mangrove protection and maintaining natural food sources benefit the Asian Koel. Since it is a non-threatened species, it continues to thrive in the region.

Cultural Significance

• The Asian Koel is deeply embedded in Indian culture and folklore, often symbolizing love, longing, and springtime.
• It is frequently mentioned in Indian poetry, literature, and music, admired for its distinctive song.

Conclusion

The Asian Koel (Eudynamys scolopaceus) is a fascinating bird with unique reproductive strategies and a significant role in the ecosystem. Its presence in the Sundarban highlights the richness of the region’s avifaunal diversity. Through its seed dispersal and interaction with host birds, it continues to influence the balance of mangrove forests and nearby habitats. Protecting the Sundarban ensures the continued survival of this mystical songbird.