The Nicobar pigeon

 

 From Wikipedia,

By- Vinuri Randhula Silva,

The Nicobar pigeon (Caloenas nicobarica  is a bird found on small islands and in coastal regions from the Andaman and Nicobar Islands, India, east through the Malay Archipelago, to the Solomons and Palau. It is the only living member of the genus Caloenas alongside the extinct spotted green pigeon,

It is a large pigeon, measuring 40 cm (16 in) in length. The head is grey, like the upper neck plumage, which turns into green and copper hackles. The tail is very short and pure white. The rest of its plumage is metallic green. The strong legs and feet are dull red. The irises are dark.

Females are slightly smaller than ales; they have a smaller bill knob, shorter hackles and browner underparts. Immature birds have a black tail and lack almost all iridescence. There is hardly any variation across the birds' wide range. Even the Palau subspecies C. n. pelewensis has merely shorter neck hackles, but is otherwise almost identical.

It is a very vocal species, giving a low-pitched repetitive call

The Nicobar pigeon's breeding range encompasses the Andaman and Nicobar Islands of India, the Mergui Archipelago of Myanmar, offshore islands of south-western Thailand, Peninsular Malaysia, southern Cambodia and Vietnam, and many of the small islands between Sumatra, the Philippines and the Solomon Islands. On Palau, the only distinct subspecies C. n. pelewensis is found. 

The white tail is the most conspicuous feature of adult Nicobar pigeons, particularly when seen at a distance in the twilight.

The Nicobar pigeon roams in flocks from island to island, usually sleeping on offshore islets where no predators occur and spends the day in areas with better food availability, not shying away from areas inhabited by humans. Its food consists of seeds, fruit and buds, and it is attracted to areas where grain is available. A gizzard stone helps to grind up hard food items. Its flight is quick, with regular beats and an occasional sharp flick of the wings, as is characteristic of pigeons in general. Unlike other pigeons, groups tend to fly in columns or single file, not in a loose flock. The white tail is prominent in flight when seen from behind and may serve as a sort of "taillight", keeping flocks together when crossing the sea at dawn or dusk. The young birds' lack of a white tail is a signal of their immaturity clearly visible to conspecifics – to an adult Nicobar pigeon, it is obvious at a glance which flock members are neither potential mates, nor potential competitors for mates, nor old enough to safely guide a flock from one island to another

This species nests in dense forest on offshore islets, often in large colonies. It builds a loose stick nest in a tree. It lays one elliptical faintly blue-tinged white egg

In 2017, several individual Caloenas nicobarica were sighted in the Kimberley region of Western Australia with a juvenile captured at Ardyaloon (One Arm Point), near Broome - the first time the bird has been sighted on the Australian mainland.

Conservation 

Nicobar pigeons are hunted in considerable numbers for food, and also for their gizzard stone which is used in jewellery. The species is also trapped for the local pet market, but as it is on CITES Appendix I, commercial international trade is prohibited. Internationally, captive breeding is able to supply the birds demanded by zoos, where this attractive and unusual bird is often seen. Direct exploitation of the species, even including the illegal trade, might be sustainable on its own; however, its available nesting habitat is decreasing. The offshore islets which it requires are often logged for plantations, destroyed by construction activity, or polluted by nearby industry or harbours. Also, increased travel introduces predators to more and more of the breeding sites, and colonies of the Nicobar pigeon may be driven to desert such locations or be destroyed outright. Though the bird is widely distributed and in some locations very common --even on small Palau it is still reasonably plentiful, with an estimated 1,000 adult birds remaining—its long-term future is increasingly jeopardized. For these reasons, the IUCN considers C. nicobarica a near threatened species.