Manchurian reed-warbler (Acrocephalus tangorum)
| Also known as: | Manchurian reed warbler |
|---|---|
| Synonyms: | Acrocephalus agricola |
| Kingdom | Animalia |
|---|---|
| Phylum | Chordata |
| Class | Aves |
| Order | Passeriformes |
| Family | Sylviidae |
| Genus | Acrocephalus (1) |
| Size | Length: 13 cm (2) |
The Manchurian reed-warbler is classified as Vulnerable (VU) on the IUCN Red List (1).
The Manchurian reed-warbler (Acrocephalus tangorum) is named after Manchuria, the historical name for northeast Asia. A small bird with fairly drab colouration and uniform tawny-brown upperparts, the Manchurian reed-warbler is distinguished by the bold white stripe which runs from the base of the beak, above the eye and towards the back of the head. This distinctive white band is bordered by a dark eyebrow and a narrower white eye-stripe. The chin, throat and belly of the Manchurian reed-warbler are white, while the flanks are buffish-brown, becoming greyish-brown on the legs (2).
The iris of the adult Manchurian reed-warbler is reddish or chestnut-brown, while juveniles usually have a dull, dark brown or slightly grey-tinged iris (2).
The Manchurian reed-warbler’s song is similar to that of other members of its genus, and is usually a sharp ‘chik-chik’ call, along with harsh ‘chr-chuck’ and slurred ‘zack-zack’ sounds (2).
The Manchurian reed-warbler was previously considered a subspecies of either the paddyfield warbler (Acrocephalus agricola) or the black-browed reed-warbler (Acrocephalus bistrigiceps), but has since been classified as a distinct species in its own right (2) (3).
The Manchurian reed-warbler breeds in southeast Russia and northeast China. It migrates to Thailand, particularly the Khao Sam Roi Yot region, as well as Laos and Cambodia for the winter (2). This species sometimes occurs as a passage migrant in Vietnam (2).
The recently discovered population in Cambodia appears to be a major stronghold for the Manchurian reed-warbler (2).
As its name suggests, the Manchurian reed-warbler’s primary habitat is reed beds. It usually inhabits reed beds dominated by the genus Phragmites, which can reach up to six metres in height (3).
In Hong Kong, the Manchurian reed-warbler is typically sighted in reeds around overgrown fields and fishponds, while in Cambodia it is found in tall stands of grass away from water, as well as in sedges, swamps and scrubby grassland (2).
Little is known about the biology of the Manchurian reed-warbler but it is thought that, like most other species in the genus Acrocephalus, it is an insect predator. A characteristic behaviour of the Manchurian reed-warbler is to climb to the top of reed stems with its tail cocked while it feeds, thereby distinguishing it from other closely-related species such as the black-browed reed-warbler (3).
The adult Manchurian reed-warbler undergoes a partial moult of its body feathers in the non-breeding season, from early autumn to late spring. It will lose and replace its main body feathers, tail and flight feathers, or tertials, before migrating to its breeding grounds in the spring (3).
The main threat to the survival of the Manchurian reed-warbler is habitat loss. Reed beds throughout this species’ range are being converted into plantations of casuarinas, eucalyptus and coconut palms, especially in Khao Sam Roi Yot, Thailand. Other areas of freshwater marsh are being turned into prawn farms, leading to an influx of salty and brackish water. Elsewhere, marshes and reed beds are threatened by land reclamation and urbanisation (2).
In Cambodia, the Manchurian reed-warbler may be potentially threatened by the extensive burning of grasslands during the dry season (2).
The Manchurian reed-warbler is listed on Appendix II of the Convention on Migratory Species (CMS or Bonn Convention), which aims to promote international cooperation between countries and conserve migratory species, their habitats and their migration routes (4). However, attempts to secure the future of these birds in Khao Sam Roi Yot by both national and international organisations have so far been unsuccessful (2).
Surveys of suitable habitat in both the Manchurian reed-warbler’s breeding and wintering range need to be carried out so that the population size and distribution of this species can be properly estimated. Additional recommended conservation measures for the Manchurian reed-warbler include marking and protecting Khao Sam Roi Yot National Park in Thailand (2).
Furthermore, work to restore reed beds throughout Southeast Asia would benefit the Manchurian reed-warbler, while encouraging Thailand to ratify the Ramsar Convention on wetlands would also help to safeguard this species’ populations (2).
For more information on the Manchurian reed-warbler:
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BirdLife International - Manchurian reed-warbler:
http://www.birdlife.org/datazone/speciesfactsheet.php?id=30018
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
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- Brackish: slightly salty water, usually a mixture of salt and freshwater, such as that found in estuaries.
- Flight feathers: the feathers at the end of the wing, involved in flight.
- Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- Moult: shedding of (usually) the outermost body covering (such as feathers, fur or skin) during growth and development, or at specific times of the year.
- Passage migrant: a species that stops for a short time in regions along its migration route in order to feed.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
- Tertials: flight feathers attached to the upper arm (humerus) of the wing.
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IUCN Red List (November, 2011)
http://www.iucnredlist.org/ -
BirdLife International (November, 2011)
http://www.birdlife.org/datazone/speciesfactsheet.php?id=30018 - Round, P.D. and Rumsey, S.J. (2003) Habitat use, moult and biometrics in the Manchurian reed-warbler Acrocephalus tangorum wintering in Thailand. Ringing and Migration, 21: 215-221.
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Convention on Migratory Species (CMS) (November, 2011)
http://www.cms.int/