Columba argentina

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Cladus: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Neoaves
Cladus: Columbimorphae
Ordo: Columbiformes

Familia: Columbidae
Subfamilia: Columbinae
Genus: Columba
Species: Columba argentina
Name

Columba argentina Bonaparte, 1855
References

Conspectus generum avium 2 p.36 BHL
IUCN: Columba argentina Bonaparte, 1855 (Critically Endangered)

Vernacular names
català: Colom argentat
čeština: Holub stříbrný
Cymraeg: Ysguthan arian
Deutsch: Silbertaube
English: Silvery Pigeon
Esperanto: Arĝenta kolombo
فارسی: کبوتر نقره‌ای
suomi: Hopeakyyhky
français: Pigeon argenté
magyar: Ezüstgalamb
Bahasa Indonesia: Merpati-hutan perak
日本語: ギンモリバト
Nederlands: Zilverduif
norsk: Sølvdue
پنجابی: چاندی کبوتر
português: Pombo-prateado
svenska: silverduva
中文: 銀鴿

The silvery pigeon (Columba argentina), also known as silvery wood-pigeon or grey wood-pigeon, is a species of pigeon found in Indonesia and Malaysia. It was thought to be extinct but wild populations rediscovered in 2008 near Masokut Island of the Mentawai archipelago might represent this species, and photographs from Simeulue confirm its existence there.
Description

The silvery pigeon is indistinguishable from the pied imperial pigeon at a distance, although this is not necessarily true vice versa; as the pied imperial pigeon can vary between a pale grey, pure white and even yellowish colouration, it is often possible to tell that a bird is not a C. argentina. At close quarters, the silvery pigeon may be recognized by a few characteristics: The plumage is always a pale silvery grey, with black remiges and ends of the tail feathers; there may be a slight greenish sheen on the feathers of the backsides of the neck. The black part of the tail is equal in length in all feathers, whereas it forms a black triangle pointing headwards on the underside of the pied imperial pigeon's tail.[2]

Most distinguishing characteristics are located on the head, which is shaped differently, with a sloping forehead (rounded in the PIP), conspicuous dark red or purplish eye-wattles (none in the PIP) and eyes, and a bill that is darker at the base (lighter at the base in the PIP), being dusky purple with a pale apple-green tip. The feet are bluish-grey, mottled with varying amounts of red. The birds are slightly smaller than the PIP, with a total length of around 36 cm, females being marginally larger and darker than males on average, and juvenile birds are apparently more sandy-coloured on the upperpart feather fringes and breast. While the weight is not recorded, comparison with related species gives an estimate of 350 grams on average.

The colour pattern, unusual for a Columba pigeon, probably represents convergent evolution towards the PIP, and possibly even a case of Müllerian mimicry, the anti-predator attribute being the PIP's habit to aggregate in large flocks which makes it harder for predators to pick out individual birds, and enables the much rarer silvery pigeon to share this advantage.
Distribution

This species was recorded during the late 19th and early 20th century from offshore islands of the Natuna Sea (west of Borneo) and west of Sumatra, Indonesia, and on the adjacent mainland. The oldest record is that of a specimen supposedly taken near Pontianak before 1850. Verifiable records exist from Burong Island, Sarawak (1899), Saya in the Lingga Islands (same year), Simeulue (e.g. Teluk Dalam and Teluk Labuan Bajau, 1901), South Pagai (1902) and Sipura in the Mentawai Islands, the Riau Islands (several times), Tuangku Airdingin (1913), Jemaja Andriabu in the Anamba Islands (1925), the North Natuna Islands (1928), and in Sumatra's Jambi and possibly South Sumatra provinces. Locations recorded earlier included Bintan in the Riau Islands (June 1930) and Pulau Gurungan Besar in the Karimata islands (March 1931) and (unconfirmed, before 1937) from Pulau Jarak in the Straits of Malacca. The species was rediscovered by a photograph - "2008 one individual was photographed between the islets of Mastokut Island and Simaimu Islands, off the southern tip of Siberut in the Mentawai Islands, Indonesia, confirming that the species survives in the wild."

Bulletin of the British Ornithologists' Club Vol. 129, (September) 2009. LEE, M. T., DONG, D. L. & ONG, T. P. A photographic record of Silvery Pigeon Columba Argentina from the Mentawai Islands, Indonesia, with notes on identification, distribution and conservation
Ecology

The silvery pigeon is known from mangrove forests and other woodland in the low-lying offshore islands and adjacent coastal regions, at an altitude below 100 m ASL. It is believed to wander around following fruit in season, and was often found in association with much larger flocks of the pied imperial pigeon. It also breeds in these birds' nesting colonies, probably over a period of several months from March/April on. Like most other pigeons, it builds a flimsy stick nest in trees and lays a single white egg, which has a chalky, not glossy shell (as opposed to that of the PIP).
Current status

This species has been classified as Critically Endangered (D1) by BirdLife International, translating into an estimated population of less than fifty mature individuals. This is based on a lack of confirmed sightings, however, and thus the species may actually be more common and simply not identified due to its resemblance with the pied imperial pigeon.

The reasons for the bird's apparent decline are not well known. While deforestation, especially the removal of mangrove forests, certainly adversely affects this bird, it is not known to have started on a massive scale at such an early date. Similarly, introduction of alien predators (like cats that become feral) will jeopardize breeding on offshore islets, but this is also not believed to have been significant at the time the records ceased. At any rate, the species is not found anymore on Burong, the Mentawi and the Riau Islands today, and likely only occurs on Siberut, Simeulue, and some of the surrounding islets.

There are some 1980s and 1990s records, supposedly of large numbers of individuals, from Padang-Sugihan Wildlife Reserve and Sembilang River in South Sumatra, and Berbak National Park in Jambi province. It is conjectured that the bird may exist, possibly in considerable numbers, in South Sumatra, especially the Banyuasin peninsula, or Padang-Sugihan Wildlife Reserve. None of these records has been verified, however, and the species was never considered to be particularly numerous, especially when compared to the PIP. Most recently, the silvery pigeon was believed to have been seen on Pulau Talang Besar, Talang Talang Islands (part of Talang-Satang National Park), in 2001 (Wilson, 2004). Butchart et al. (2006) also mention an unconfirmed record in 2002.

In 2011 individuals observed for the first time at Tanahbala in the Batu Islands were also associating with Pied and Green Imperial Pigeons. In 2016, a zoo in Nias discovered two silvery pigeons in captivity, when they were performing inventory.[3]
References

BirdLife International (2019). "Columba argentina". IUCN Red List of Threatened Species. 2019: e.T22690195A155300126. doi:10.2305/IUCN.UK.2019-3.RLTS.T22690195A155300126.en. Retrieved 13 November 2021.
Goodwin, D (1959). "Taxonomy of the genus Columba". Bulletin of the British Museum (Natural History). 6: 1–23. doi:10.5962/bhl.part.26842.

"Critically Endangered Silvery Pigeons discovered at the Museum Zoo". 17 December 2016.

Bonaparte, Charles Lucien Jules Laurent (1855): 32 *1. Myristicivora grisea. In: Conspectus generum avium 2: 36. PDF fulltext available at Gallica: search for "Bonaparte" and "Conspectus"
Butchart, S. H. M.; Collar, N. J.; Crosby, M. J. & Tobias, J. A. (2005): Asian enigmas: Lost and poorly known birds: targets for birders in Asia. Birding Asia 3: 41–49. HTML fulltext
Butchart, S. H. M.; Stattersfield, A. J. & Brooks, T. M. (2006): Going or gone: defining 'Possibly Extinct' species to give a truer picture of recent extinctions. Bull. B. O. C. 126A: 7-24. PDF fulltext
Collar, N. J.; Andreev, A. V.; Chan, S.; Crosby, M. J.; Subramanya, S. & Tobias, J. A. (editors) (2001): Silvery Wood-pigeon. In: Threatened Birds of Asia: The BirdLife International Red Data Book, 1550–1552. BirdLife International. ISBN 0-946888-44-2 HTML fulltext
Gibbs, David; Barnes, Eustace & Cox, John (2001): Pigeons and Doves. A&C Black, London. ISBN 1-873403-60-7
Wilson, Kerry-Jayne (2004): Notebook: A provisional sighting of the Silvery Pigeon on the Talang Talang Islands, Sarawak, Malaysia. Birding Asia 1: 55–57.
Lee, Mark T., Yong Ding Li & Ong Tun Pin (2009): A photographic record of Silvery Pigeon Columba argentina from the Mentawai Islands, Indonesia, with notes on identification, distribution and conservation In: Bulletin of the British Ornithological Club 129(3): 122–128.