Nicobar Pigeon

About the Nicobar pigeon

The Nicobar pigeon, also called the Nicobar dove, is a striking bird of small islands and coastal regions stretching from the Andaman and Nicobar Islands of India, east through the Indonesian Archipelago, to the Solomon Islands and Palau. It holds a notable place in pigeon evolution: it's the only living member of its genus, Caloenas, alongside two extinct relatives, the spotted green pigeon and the Kanaka pigeon, and it's considered the closest living relative of the extinct dodo and Rodrigues solitaire. Molecular and anatomical evidence suggests the Nicobar pigeon's lineage split from that of the dodo and its kin sometime during the Eocene, roughly 56 to 34 million years ago, though the dating tools used for that estimate have since turned out to be unreliable.

The bird measures 32 to 35 cm (13 to 14 in) long. Its head and upper neck are grey, shading into iridescent green-and-copper hackles, while the tail is short and pure white in contrast to the rest of its plumage, which is metallic green and can look black in dim light. The dark bill carries a small blackish knob at its base, called a cere, and the legs and feet are a dull red. Females, at 490 to 600 grams, run slightly heavier on average than males at 460 to 525 grams, though the two overlap considerably; females also have a smaller bill knob and browner underparts. Young birds lack a white tail and most of the adult iridescence — a visible signal to other Nicobar pigeons that they aren't yet old enough to guide a flock between islands or compete for mates.

Two subspecies are recognized: the widespread C. n. nicobarica, and C. n. pelewensis, confined to Palau, which is marginally smaller with slightly shorter neck hackles but otherwise nearly identical.

Behavior and diet

Nicobar pigeons are highly social and mobile, roaming in flocks from island to island. They typically sleep on predator-free offshore islets and spend their days on islands with better food, including areas inhabited by people, feeding on seeds, fruit, and buds and gathering wherever grain is available; a gizzard stone helps grind up tougher food. In flight, the species moves quickly with regular wingbeats and occasional sharp flicks, and — unusually for pigeons — flocks travel in columns or single file rather than loose groups. Researchers think the bird's prominent white tail may act as a kind of visual beacon, helping flock members stay together when crossing open water at dawn or dusk; birds crossing between islands typically fly at least 60 meters above the sea.

The species nests in dense forest on offshore islets, often in large colonies, building a loose stick nest in a tree and laying a single elliptical, faintly blue-tinged white egg. It's a vocal bird, giving a low, repetitive call. There's little physical variation across its wide geographic range — even the geographically isolated Palau subspecies differs from the mainland form only in slightly shorter neck hackles.

Range and habitat

The Nicobar pigeon's breeding range covers the Andaman and Nicobar Islands of India, the Mergui Archipelago of Myanmar, offshore islands of southwestern Thailand, Peninsular Malaysia, southern Cambodia and Vietnam, and many small islands scattered between Sumatra, the Philippines, and the Solomon Islands, with the distinct Palau subspecies found only on that island. The birds favor small islands and coastal habitat, roosting on predator-free islets and nesting in dense forest cover on offshore land.

The species has occasionally strayed outside its usual range: individuals were found in the Kimberley region of Western Australia in 2017 (the first confirmed sighting on the Australian mainland, with a juvenile captured near Broome) and on Green Island off Cairns in 2023. On the Nicobar Islands themselves, the significant colony on the remote islet of Batti Malv survived the 2004 Indian Ocean tsunami with the lighthouse there only lightly damaged, though a 2007 survey found the tower "totally covered" in vines — a sign of vigorous regrowth, but possibly also of severe earlier damage to the island's mature forest.

Conservation status

The Nicobar pigeon is listed as Near Threatened on the IUCN Red List, in a 2021 assessment by BirdLife International. It is widely distributed and still common in places, but its long-term future is increasingly in doubt.

It is hunted in considerable numbers for food and for its gizzard stones, which are sometimes used in jewelry, and it is trapped for the local pet market. Because it is on CITES Appendix I, commercial international trade is prohibited, and captive breeding meets the demand for birds abroad.

Habitat loss is the bigger long-term threat. The offshore islets the pigeon needs for nesting are often logged for plantations, cleared for construction or polluted by nearby industry and harbors, and increased travel carries predators to more breeding sites, which can drive colonies away or destroy them. The bird is still reasonably plentiful in some places, including small Palau, with an estimated 1,000 adults.