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Mekong Wagtail Motacilla samveasnae

Justification
This species has a restricted linear range and a small population. It is highly tolerant of human presence, and its habitat is not particularly vulnerable to human-induced changes. However, the many dams currently proposed for the Mekong, particularly those on sections where the river has a low gradient, have the potential to disrupt long stretches of its riverine range by flooding the river channel. Its small to moderately small population is therefore projected to undergo a moderately rapid decline over the next three generations and it is thus classified as Near Threatened.

Taxonomic source(s)
Duckworth, J. W.; Alstr

Taxonomic note
Described as new to science by Duckworth et al. (2001).

Distribution and population
Motacilla samveasnae is known, in the breeding season, from a substantial length of the River Mekong and several of its tributaries in Cambodia, extending upstream from Kampi into southern Laos, and there is a record from the non-breeding season in Thailand. The species was first recorded in Vietnam in 2002, where it is likely to be a resident breeder (Le Tron Trai and Craik 2008). In optimal habitat, linear densities may reach many pairs per kilometre, and its numbers are certainly healthy in Cambodia.

Population justification
A preliminary population estimate of 10,000-19,999 individuals assumes that the species's population is moderately small owing to its highly specialised habitat requirements and restricted distribution. This estimate equates to 6,667-13,333 mature individuals, rounded here to 6,000-15,000 mature individuals.

Trend justification
Moderately rapid declines are suspected to take place in the next three generations owing to the proposed construction of a number of dams, which will almost certainly impact upon the species's specialised habitat.

Ecology
It breeds in riverine "channel mosaic" habitat, typically in broad, lowland rivers, where the streambed is exposed to provide rocky outcrops and bushland, gravel shoals and/or sandbars, tufted grasses and annual dicotyledons. It avoids wooded areas. It will regularly feed within bushes in the water, walking along branches and picking food items from these and from leaves.

Threats
It is highly tolerant of human presence, and its habitat is not particularly vulnerable to human-induced changes. However, the many dams currently proposed for the Mekong, particularly those on sections where the river has a low gradient, have the potential to disrupt long stretches of its riverine range by flooding the river channel.

Conservation Actions Underway
Short sections of its habitat occur in several protected areas, but this is unlikely to afford much protection from dam development. Active conservation for this and other riverine wetland species will centre on holistic review and modification of proposals for large dams, and will necessitate international cooperation. Conservation Actions Proposed
Carry out surveys to assess the total population size. Monitor population trends through regular surveys. Encourage the completion of environmental impact assessments prior to dam construction along the Mekong River channel and ensure that recommendations are acted upon. Mitigate against any likely habitat loss that may result from dam construction.

References
Alström, P.; Mild, K. 2003. Pipits and wagtails of Europe, Asia and North America. Christopher Helm, London.

Duckworth, J. W.; Alström, P.; Davidson, P.; Evans, T. D.; Poole, C. M.; Setha, T.; Timmins, R. J. 2001. A new species of wagtail from the lower Mekong basin. Bulletin of the British Ornithologists' Club 121(3): 152-182.

Le Tron Trai; Craikl, R. C. 2008. Mekong Wagtail Motacilla samveasnae - resident breeder in Vietnam? BirdingASIA 9: 68-69.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Text account compilers
Benstead, P., Bird, J., Taylor, J.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Motacilla samveasnae. Downloaded from http://www.birdlife.org on 13/07/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 13/07/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Mekong wagtail (Motacilla samveasnae) 0

Key facts
Current IUCN Red List category Near Threatened
Family Motacillidae (Wagtails and pipits)
Species name author Duckworth, Alstr
Population size 6000-15000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 37,900 km2
Country endemic? No
Links to further information
- Additional Information on this species