34.
Tooth-billed Pigeon
(Didunculus strigirostris)
EN
Overview
Nicknamed the ‘little Dodo’, the Tooth-billed Pigeon is one of the closest living relatives to the iconic extinct Dodo. Unfortunately, like the Dodo, this species is on the verge of extinction. It is found in the primary forests of Samoa, huge areas of which have been destroyed to make way for agriculture. Hunting of the Tooth-billed Pigeon is now prohibited, but annual hunts in the past have been responsible for the deaths of thousands of individuals. The species is highly secretive and had not been sighted for several years until December 2013 during surveys of Savai’i. Surveys of remote areas are needed to locate undiscovered pockets of individuals and remaining habitat needs to be effectively protected.
Urgent Conservation Actions
Extensive searches of suitable habitat are needed to assess range and numbers.
Distribution
Endemic to Samoa, this species occurs on the islands of Upolu and Savai’i.
Fact
The Tooth-billed Pigeon is one of the closest living relative to the iconic, extinct Dodo. Its Latin name Didunculus means ‘little Dodo’.
Evolutionary Distinctiveness
Order: Columbiformes
Family: Columbidae

The Columbidae are a large avian family consisting of some 310 species of pigeon and dove. The Tooth-billed Pigeon is the only living member of the genus Didunculus. DNA analysis shows that it is closely related to the iconic extinct Dodo.

The tree below shows the evolutionary relationships between this species and all other birds. The colours of the tree indicate EDGE scores with the red shades indicating the higher priority species; the bright red leaves correspond to the top 100 EDGE bird species. Further information on every species can be found by zooming in to its leaf on the tree.
Description
Size: 
31cm
The most unique feature of this bird is its large, hooked bill, which sports two ‘teeth’ on the lower mandible. The bill is red at the base, becoming yellow towards the tip. The eye rings are also red. It is thick-bodied for a pigeon, with dark grey-green, iridescent feathers on the head neck and throat. The back, tail and wings are a chestnut colour. The legs and feet are a dark red. Juveniles are duller with browner colouration of the head.
Ecology
The Toothed-billed Pigeon’s bill is adapted to saw through tough seeds of Dysoxylum species of tree, which are related to mahogany. It will also eat other types of fruit. During the breeding season, the pigeon is thought to lay two eggs. A Tooth-billed Pigeon nest has never actually been documented and very little is known about the species’ ecology.
Habitat
The Tooth-billed Pigeon inhabits primary forest at all altitudes up to 1,600 m. Individuals have been observed at the forest edge, along forest roads and will enter into clearings.
Distribution
Endemic to Samoa, this species occurs on the islands of Upolu and Savai’i. It is known from ten localities on Savai’i, but there are remote areas of forest on the island that have not been surveyed. A tiny population was recorded in Upolu in 2009, but no sightings in this area have been made since.
Population Estimate

The population was estimated at 600–1,700 adults in 2000. However, the lack of recent records suggests that the total population may now be far lower than this, possibly fewer than 250 mature individuals.

Population Trend

Declining. The total population was estimated at 4,800-7,200 birds in the mid-1980s but has declined drastically since.

Status
Endangered
Threats
The greatest threat to the Tooth-billed Pigeon is loss of its forest habitat, which is cleared to make way for agriculture. Cyclones also have a devastating impact on forests, and can seriously decrease canopy cover, in some case by as much as 100 per cent. Cyclone in 1990 and 1991 reduced canopy cover from 100 per cent to 27 per cent. Tall trees are also brought down by extreme weather, with almost 95 per cent being lost at some sites. Following such events, fast-growing invasive plants often out-compete native tree species, hampering the recovery of original habitat. Hunting of the Tooth-billed Pigeon is now prohibited, but annual hunts in the past have been responsible for the deaths of thousands of individuals. Current shooting drives of unprotected species result in the accidental killing of some Tooth-billed Pigeons. Rats are thought to prey on eggs and chicks.
Conservation Underway

The Tooth-billed Pigeon is the national symbol for Samoa, where it is known as Manumea, and a flagship species for conservation. In 2007, it was the mascot for the Pacific Games, featuring on materials to raise awareness about forest conservation. Hunting of the pigeon is prohibited, but protection is not reinforced. The species does occur in some protected areas, the integrity of which has been affected by cyclones. The Samoan Ministry of Natural Resources and Environment have developed a recovery plan for the pigeon. Surveys of the remote regions of Savai'i are planned for the future.

Conservation Proposed

Funds are needed to carry out the actions in the species recovery plan. The hunting of native pigeons in Samoa should be prohibited to ensure Tooth-billed Pigeons are not killed accidentally. Extensive searches of suitable habitat are needed to gain an accurate assessment of range and numbers. Research into the ecological needs and threats facing the species is also needed. Essential breeding and feeding sites need to be located, protected and monitored and sanctuaries may need to be created on offshore islands. Further efforts should be made to raise awareness of the species’ precarious conservation status amongst local people and engage them in conservation activities. It is also recommended that the feasibility of a creating a captive population be assessed as a source to bolster wild numbers.

Links
References
Beichle, U. and Maelzer, M. (1985). A conservation programme for Western Samoa. In: Diamond, A.W. and Lovejoy, T.E. (ed.), Conservation of tropical forest birds, pp. 297-299. International Council for Bird Preservation, Cambridge, U.K.

Beichle, U. (1991). Status and acoustical demarcation of pigeons of Western Samoa. Notornis 38(1):81–86

Beichle, U. (2006). Saving Samoa’s Critically Endangered Maomao and Manumea. Unpublished final report to Wildlife Conservation Society, June 2006, 20pp

Birdlife International. (2000) Threatened Birds of the World, Lynx Editions and Birdlife International, Barcelona, Spain and Cambridge, U.K.

BirdLife International (2013) Species factsheet: Didunculus strigirostris. Downloaded from www.birdlife.org on 18/07/2013.

Blockstein, D. E. (1987) Preliminary report on the ecology and status of the Tooth-billed Pigeon or Manumea (Didunculus strigirostris) in Western Samoa.

Elmqvist, T., Rainey, W. E., Pierson, E. D. and Cox, P. A. (1994) Effects of tropical cyclones Ofa and Val on the structure of a Samoan lowland rain forest. Biotropica 26:384–391

MNRE. (2006) Recovery Plan for the Manumea or Tooth-billed Pigeon (Didunculus

strigirostris). Ministry of Natural Resources & Environment, Samoa. 41pp

SPREP. (1999) Proceedings of the Polynesian Avifauna Conservation Workshop held in Rarotonga, 26-30 April 1999.

Steadman, D.W. (2006). An extinct species of tooth-billed pigeon (Didunculus) from the Kingdom of Tonga, and the concept of endemism in insular landbirds. Journal of Zoology 268 (3):233
Acknowledgements
Text compiled by Michelle Harrison.

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