Tooth-billed pigeon

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Tooth-billed pigeon/ manumea
Didunculus.jpg
Live specimen in 1901
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Columbiformes
Family: Columbidae
Genus: Didunculus
Peale, 1848
Species: D. strigirostris
Binomial name
Didunculus strigirostris
(Jardine, 1845)

The tooth-billed pigeon (Didunculus strigirostris), also known as the manumea, is a large pigeon found only in Samoa. It is the only living species of genus Didunculus. A related extinct species, the Tongan tooth-billed pigeon (Didunculus placopedetes), is only known from subfossil remains in several archeological sites in Tonga.[2][3] The tooth-billed pigeon is the national bird of Samoa and featured on the 20 tālā bills and the 50 sene pieces of the 2008/2011 series.

Description[edit]

Illustration by John Gould (probably from stuffed specimens)
Illustration in habitat by Gustav Mützel

The tooth-billed pigeon is a medium-sized, approximately 31 cm long, dark pigeon with reddish feet and red bare skin around the eye. The underparts, head and neck are greyish with a slight blue-green iridescence, and the tail, wings-coverts and tertials are rufous chestnut, while the remaining remiges are blackish. It has a large, curved, and hooked bright red bill with toothlike projections on the lower mandible. Both sexes are similar, but the juvenile is duller with a browner head, with a black bill with only the base a pale orange.

Taxonomy and systematics[edit]

The species was probably found in October or November 1839, by the United States' Exploring Expedition under Commander Wilkes. The discovery of the bird was announced by Hugh Edwin Strickland in September 1844 as being among the rarities obtained by Mr. Titian Peale, the naturalist of the expedition. The formal description was made by William Jardine (Ann. Nat. Hist. xvi. p. 175, plate 9), under the name of Gnathodon strigirostris, although that genus name was already in use for a mollusc.[4]

It has no close living relative, but it has been shown to be genetically close to the dodo,[5] and the genus name Didunculus means "little Dodo".[6] the English name of dodlet was suggested by Sir Richard Owen. The jaw and tongue structure, and the superficially parrotlike bill have suggested a relationship to the parrots, but these features have arisen from its specialised diet rather than any real relationship.

The following cladogram, from Shapiro and colleagues (2002), shows the tooth-billed pigeon's closest relationships within Columbidae, a clade consisting of generally ground-dwelling island endemics.[5]




Goura victoria (Victoria crowned pigeon)






Caloenas nicobarica (Nicobar pigeon)




Pezophaps solitaria (Rodrigues solitaire)



Raphus cucullatus (dodo)








Didunculus strigirostris (tooth-billed pigeon)



A similar cladogram was published in 2007, differing only in the inverted placement of Goura and Dicunculus, as well as in the inclusion of the pheasant pigeon and the thick-billed ground pigeon at the base of the clade.[7]

Distribution and habitat[edit]

The tooth-billed pigeon is confined to undisturbed forests of Samoa in the Pacific. Natural habitats for the tooth-billed pigeon in Samoa include the Central Savai'i Rainforest, Tafua Preserve, Fagaloa Bay – Uafato Tiavea Conservation Zone on Upolu Island, and Nu'ulua island. Little is known about the ecology and biology of the species but it is believed to feeds on the fruits of Dysoxylum, a tree in the mahogany family. Manuscripts from the 1800s suggest chicks are confined to the forest floor. However the location of nests (in a tree or on the ground) is still unconfirmed.

Because of ongoing habitat loss, limited range, small population size, hunting and occasional cyclones as well as the likely impact of introduced species such as pigs, dogs, rats and cats, the tooth-billed pigeon is evaluated as Endangered on the IUCN Red List of Threatened Species and is likely to be upgraded to critically endangered in the near future. Surveys suggest numbers are critical and that in 2013 only 200 birds remain, but the actual population size may be much smaller, and there are no birds currently located in captivity.[8] In addition, no chicks have been sighted during any of the surveys. It is highly likely that chick mortality is high and the observed population are an aged population of adult birds. Immediate action to save this species is required: this will require 1) conservation education to reduce hunting risk and 2) knowledge of the biology of the population and the reasons behind the current decline.

Notes[edit]

  1. ^ BirdLife International (2013). "Didunculus strigirostris". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ Hume, J.P., Walters, M. (2012). Extinct Birds. London: T & AD Poyser. p. 544. ISBN 978-1-4081-5725-1. 
  3. ^ Tyrberg, T. (2009). "Holocene avian extinctions". In Turvey, S.T. Holocene extinctions. Oxford, UK: Oxford University Press. p. 352. ISBN 978-0-19-953509-5. 
  4. ^ Newton, Alfred (1893–1896). A Dictionary of Birds. London: Adam & Charles Black. p. 154. 
  5. ^ a b Shapiro, B.; Sibthorpe, D.; Rambaut, A.; Austin, J.; Wragg, G. M.; Bininda-Emonds, O. R. P.; Lee, P. L. M.; Cooper, A. (2002). "Flight of the Dodo". Science 295 (5560): 1683. doi:10.1126/science.295.5560.1683. PMID 11872833.  Supplementary information edit
  6. ^ Rauzon, Mark J. (2007). "Island restoration: Exploring the past, anticipating the future". Marine Ornithology 35 (2): 97–107. 
  7. ^ Pereira, S. L.; Johnson, K. P.; Clayton, D. H.; Baker, A. J. (2007). "Mitochondrial and nuclear DNA sequences support a Cretaceous origin of Columbiformes and a dispersal-driven radiation in the Paleogene". Systematic Biology 56 (4): 656–672. doi:10.1080/10635150701549672. PMID 17661233.  edit
  8. ^ Extinction warning: racing to save the little dodo from its cousin's fate

References[edit]

External links[edit]