Mapping the potential habitats of Nicobar Megapode – An endemic bird of Nicobar Islands, India

Abstract

The Nicobar megapode (Megapodius nicobariensis), classified as vulnerable by the IUCN, is endemic to the Nicobar Islands in the Bay of Bengal. This terrestrial bird is known for its mound-building behavior for incubation and prefers coastal habitats. This species has suffered a sharp population decline following the 2004 Indian Ocean tsunami and the coastal subsidence. Coastal land sinking that ranged between 2.85–1.1 m in the Nicobar Islands resulted in irreversible loss of coastal habitats, and the area of suitable habitat available for this species remains unexplored. This study used MaxEnt algorithm to analyze the habitat suitability of Nicobar megapode across the Nicobar Islands. A total of 103 unique occurrence points were compiled from research papers, scientific reports, a PhD thesis, and the eBird platform. Nine environmental variables were used and the model demonstrated strong performance and robustness with an AUC value of 0.90. The key factors influencing the species’ distribution were distance from the beach (60.3 %), followed by canopy height (13.4 %), elevation (9.1 %) and distance from road (6.6 %). The model indicated that the Nicobar megapode prefers habitats with moderately dense forests, canopy height ranging between 5–20 m near sandy beaches of coastal forests. The highest amount of suitable habitats was found on the Great Nicobar Islands (31.39 km²), Teressa Island (11.39 km²), Little Nicobar Island (9.74 km²) and Nancowry Island (6.53 km²). These findings highlight the critical role of coastal forests, especially in the larger islands like Great Nicobar, Teressa and Little Nicobar in supporting the long-term conservation of the Nicobar megapode.