Nicobar Megapode

The Nicobar Megapode (Megapodius nicobariensis) is a rare and distinctive ground-dwelling bird endemic to the Nicobar Islands of India, located in the eastern Indian Ocean. Belonging to the family Megapodiidae, commonly known as mound-builders or scrubfowl, this species is unique for its remarkable nesting behaviour, in which it uses decomposing vegetation to incubate its eggs. It is one of India’s few avian species restricted entirely to island ecosystems, and it plays a vital ecological role in maintaining coastal and forest habitats in the Nicobar archipelago.

Taxonomy and Classification

• Kingdom: Animalia
• Phylum: Chordata
• Class: Aves
• Order: Galliformes
• Family: Megapodiidae
• Genus: Megapodius
• Species: M. nicobariensis

The species was first described scientifically in the 19th century and is closely related to other Megapodius species found across Southeast Asia and Oceania. However, the Nicobar Megapode has evolved in geographic isolation, developing unique adaptations suited to the island environment.

Physical Characteristics

The Nicobar Megapode is a medium-sized, stocky bird, typically measuring 35 to 40 centimetres in length. It has a brownish-grey plumage, short rounded wings, and strong legs adapted for scratching and digging. The bird’s tail is short, and its head and neck display a slight reddish or grey tinge.
A distinguishing feature of the species is its large, powerful feet and claws, which it uses to build and maintain nesting mounds. Its flight is weak and limited to short distances, and it generally moves by running swiftly through dense undergrowth. The Nicobar Megapode’s call is a deep, resonant “oom-oom” or “whoo-whoo” sound, especially heard during the breeding season.

Distribution and Habitat

The Nicobar Megapode is endemic to the Nicobar Islands, a chain of tropical islands in the southeastern part of the Andaman and Nicobar archipelago, under Indian administration. It inhabits a range of habitats, including:

• Coastal forests and scrublands
• Sandy beaches and dunes
• Mangrove fringes
• Secondary growth forests and plantations

The species prefers areas with loose soil or sand where it can easily construct nesting mounds. Its distribution spans most of the central and southern Nicobar Islands, including Great Nicobar, Little Nicobar, Katchal, Nancowry, and Teressa, though population densities vary between islands.

Nesting and Breeding Behaviour

The Nicobar Megapode’s reproductive behaviour is its most remarkable characteristic. Unlike most birds, it does not incubate its eggs using body heat. Instead, it constructs large incubation mounds — sometimes over three metres in diameter and one metre high — made from layers of sand, soil, leaves, and decomposing vegetation.
The heat generated by microbial decomposition within the mound acts as a natural incubator. The temperature is carefully regulated by the parent birds, which add or remove materials to maintain an optimal temperature of about 33–35°C.
Females lay one large egg per clutch, weighing nearly 10% of the adult’s body weight, and may use multiple mounds during a breeding season. The incubation period lasts around 60 to 80 days, after which the chick hatches fully feathered and independent, capable of flying and foraging within hours — a remarkable adaptation among birds.

Feeding Ecology

The Nicobar Megapode is omnivorous, feeding primarily on seeds, fruits, berries, insects, small crustaceans, and other invertebrates found in forest litter or along the coast. Its foraging activity plays a crucial role in seed dispersal and soil aeration, contributing to the regeneration of forest ecosystems on the islands.

Behaviour and Ecology

This bird is largely terrestrial and shy, avoiding open areas and human presence. It is usually seen alone or in pairs, rarely forming large groups. The species is most active during early morning and late afternoon.
The Nicobar Megapode demonstrates territorial nesting behaviour, with each pair maintaining and defending their mounds year after year. The mounds are often built close to the shoreline but above the high-tide line. After the devastating 2004 Indian Ocean tsunami, many nesting sites were destroyed or inundated, causing a significant decline in local populations.

Conservation Status

The International Union for Conservation of Nature (IUCN) lists the Nicobar Megapode as Vulnerable, primarily due to its restricted range and declining habitat quality. The estimated global population is around 4,000 to 5,000 mature individuals, though numbers vary due to natural disasters and human disturbance.
Major threats include:

• Habitat loss and degradation, particularly from coastal development, plantations, and infrastructure expansion.
• Predation by invasive species such as dogs, cats, and rats, which prey on eggs and chicks.
• Natural disasters such as tsunamis, cyclones, and coastal erosion, which destroy nesting mounds.
• Human disturbance, including egg collection by local communities and tourism-related encroachment.

Following the 2004 tsunami, conservation assessments revealed a reduction in available nesting habitats, especially on southern islands. However, the species has shown resilience by relocating and constructing new mounds in higher, forested areas.

Conservation Efforts

The Nicobar Megapode is legally protected under Schedule I of the Indian Wildlife (Protection) Act, 1972, which affords it the highest degree of protection. It is also listed in Appendix I of CITES, restricting international trade.
Conservation initiatives include:

• Habitat protection within designated wildlife sanctuaries and the Great Nicobar Biosphere Reserve.
• Post-tsunami ecological surveys to monitor population recovery and nesting-site relocation.
• Community awareness programmes to reduce egg collection and promote habitat conservation.
• Scientific studies on breeding ecology, mound temperature regulation, and adaptation to environmental change.

Recent conservation strategies have focused on integrating local Nicobarese communities in protection efforts, recognising their traditional ecological knowledge and dependence on the island ecosystem.

Ecological and Cultural Significance

The Nicobar Megapode is an integral part of the Nicobar Islands’ ecosystem, contributing to nutrient cycling, seed dispersal, and forest regeneration. Its nesting mounds also serve as microhabitats for invertebrates and small reptiles, enhancing local biodiversity.
Culturally, the bird holds significance for the indigenous Nicobarese tribes, who regard it as a symbol of fertility and natural resilience. Its nesting behaviour, deeply embedded in the island’s ecology, has inspired local folklore and traditional ecological practices.

Future Prospects

Given its vulnerability to environmental change and limited range, the long-term survival of the Nicobar Megapode depends on sustained conservation efforts, strict protection of nesting habitats, and careful management of human activities in coastal regions. With the threat of rising sea levels and increased storm frequency due to climate change, adaptive management strategies are crucial to safeguard this unique island species.