Pink-necked green pigeon

Carl Linnaeus described the pink-necked green pigeon as Columba vernans in 1771. It was later moved to the green pigeon genus Treron. Within that genus the species is most closely related to the similar looking orange-breasted green pigeon of India and Southeast Asia. The species has had up to nine subspecies described, along with the nominate race, but among the important ornithological checklists the International Ornithological Congress' (IOC) Birds of the World: Recommended English Names, the Howard and Moore Complete Checklist of the Birds of the World and The Clements Checklist of Birds of the World do not accept any described subspecies as valid and all treat the species as monotypic. Only the Handbook of the Birds of the Worlds HBW Alive lists any subspecies, with the proviso that the difference between them is in many cases clinal and further research is necessary to determine if any of them are valid. It is also known as the pink-necked pigeon. ==Description==

The pink-necked green pigeon is a medium-sized pigeon, measuring in length and weighing around . The species has sexually dimorphic plumage. The male has a grey head, pinkish neck and upper breast, and the rest of the breast is orange. The back is olive green and the wings are green with black and yellow edging on the which create a yellow bar across the wing in flight. The belly is yellowish with grey flanks, and the tail is grey with a black band at the end, and a chestnut . The female is smaller overall, has a yellowish belly, throat and face, and greenish crown and back of the neck, although is otherwise similar to the male. The legs are pink or reddish, and the bill is white, pale blue green or grey. Juvenile birds look similar to females but are greyer above. Pigeons in the genus Treron are unusual in the family for not having cooing calls, instead making whistling and quacking noises, but some cooing notes have been recorded for the pink-necked green pigeon, as the male makes a tri-syballic whistling call ending in a coo. It is also reported to make a rasping krrak krrak... call, but the species is generally held to not be particularly vocal, usually only calling in communal roosts and when it finds food. ==Distribution and habitat==

The range of the pink-necked green pigeon extends from southern Myanmar, Thailand, Cambodia, and Vietnam south through the Malay Peninsula and across the Greater Sundas (and their surrounding islands), Bali, Lombok, Sumbawa, and as far east as the Moluccas as well as the Philippines. It occupies a variety of habitats, including primary forest, forest edge, secondary forest, and coastal mangroves. It is also readily found in human dominated environments such as gardens, plantations and farmland. It is more common in lowlands and close to the coast, but can be found up to in the Philippines, A related species, the thick-billed green pigeon, covers vast distances in search of fruit, and it is likely that the pink-necked green pigeon has a similar behaviour. Within the archipelago it was able to colonise Anak Krakatau, a volcano that emerged from the sea from the caldera in 1927, within 36 years of the new island suffering a large eruption in 1952. The delay between the island settling down and colonisation was likely due to the time taken for figs to become established on the island and begin fruiting. It later became extinct on that island, due to a small population and predation. The species has recently expanded its range, having colonised Flores at some time since 2000. ==Behaviour==

The pink-necked green pigeon is primarily a frugivore, taking a range of fruits, particularly figs (Ficus). Fruit of other trees are taken as well, including Glochidion, Breynia, Vitex, Macaranga, Muntingia, Melastoma, The species feeds in the mid-canopy of the forest and rarely feeds in the understory or on the ground. It is described as being agile when clinging on fine branches to reach fruits at the end. Studies of closely related species have found that not every individual has grit, and it is likely the same is true of this species. ==Ecology==

in Krakatoa Like many fruit-eating pigeons, the pink-necked green pigeon is thought to be an important disperser of fruit seeds in forests and woodlands. The grinding gizzard was thought to mean the species was entirely a seed predator instead of a seed disperser but studies of closely related species have shown that not every bird crop contains grinding stones and some seeds could pass through, and the same is likely to be true of this species. The species is thought to be one of those responsible for helping the return of many of the Ficus species to the islands of Krakatoa after the obliteration of the original island in a volcanic eruption. It may not have been responsible for the first shrubby fig species, which may have been carried by generalists such as bulbuls, but once some fruiting figs had established on the island it could have been responsible for both bringing new species of Ficus to the islands and then moving the seeds between the islands. Its flight time to the islands of Krakatoa has been estimated at 48 minutes, far shorter than the estimated seed retention time in its gut of 60–480 minutes. ==Status==

An adaptable species, T. vernans has fared well with human-made changes to its range. It has readily moved into cities and is common in Singapore's protected areas and even its gardens, In spite of suffering some hunting pressure in Thailand, Malaysia and Sumatra, it remains common there and across most of its range. Because it is not considered to be in any danger of extinction it has been evaluated as least concern by the IUCN Red List of Threatened Species. ==References==