Tuesday 22 October 2013

A new species of Tailorbird from the Mekong floodplain of Cambodia.

Tailorbirds of the genus Orthotomus are small Warblers that get their name from their method of building nests, which involves stitching the sides of a large leaf together with plant fibers or Spider silk to form a cradle, within which a woven grass nest is constructed. Unlike most Warblers, Tailorbirds are often brightly coloured. Tailorbirds are found across south and east Asia from India to the Philippines and Indonesia.

In a paper published in the journal Forktail on 25 June 2013, a team of scientists led by Simon Mahood of the Wildlife Conservation Society of Cambodia describe a new species of tailorbird from the Mekong floodplain of southern Cambodia.

The new species is named Orthotomus chaktomuk, where 'chaktomuk' is a Khmer word meaning ‘four
faces’, a reference to the confluence of the Tonle Sap, Bassac and Mekong rivers at Phnom Penh, which was formerly known as Krong Chaktomuk. It is also referred to be the English name 'Cambodian Tailorbird'.

Orthotomus chaktomuk is a 9 cm greyish Warbler with a distinctive cinnamon-brown crown. It was initially discovered during sapling of wild birds in Cambodia for avian influenza in 2009. Orthotomus chaktomuk appears to dwell close to the ground in thick evergreen scrub, between 3 and 25 m above sea-level, on the floodplains of southern Cambodia, including within Phnom Penh. It is unclear if its range extends into Vietnam.

Orthotomus chaktomuk, the Cambodian Tailorbird. Mahood et al. (2013).

Because much of the natural habitat of Orthotomus chaktomuk is under threat from expanding rice cultivation, Mahood et al. recomend that it should be classified as Near Threatened on the IUCN Red List

Orthotomus chaktomuk appears to be very closely related to another Tailorbird found in the region, Orthotomus atrogularis, the Dark-necked Tailorbird, which is widespread across south and east Asia. Mahood et al. suggest that on the grounds of morphological and genetic analysis alone the two birds would probably be classified as subspecies. However the two species appeared to live alongside one-another without interbreeding, suggesting that behavioral boundaries exist which keep the two birds separate, and which therefore justify the description of Orthotomus chaktomuk as a full species.

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