A new species of warbler has been described from the karst limestone country of Vietnam and Laos by scientists from BirdLife International, Institute of Ecology and Biological Resources, Swedish University of Agricultural Sciences, Swedish Museum of Natural History, and Wildlife Conservation Society.
Named Limestone Leaf-warbler Phylloscopus calciatilis, the new species is very similar to Sulphur-breasted Warbler P. ricketti, in morphology, but it is smaller with a proportionately larger bill and rounder wing. Its song and calls are diagnostic. Based on mitochondrial and nuclear DNA, the new species is most closely related to P. ricketti and Yellow-vented Warbler P. cantator.
"Although this was a collective effort involving a number of institutions and individuals I would like to pay particular tribute to Per Alstrom, the lead author who undertook most of the hard work, research and analysis in putting this together", said Jonathan Eames, Programme Manager of BirdLife International in Indochina.
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Limestone Leaf-warbler has been described from the limestone karst country of Vietnam and Laos Photo credit: Ulf Johansson/Swedish Museum of Natural History |
Initially, the bird was identified as a Sulphur-breasted Warbler, in itself an interesting finding, since it was apparently breeding more than 1,000 km south of its previously known breeding areas in China. Later it was realised that its songs differed markedly from the songs of the Sulphur-breasted warbler, and further studies were undertaken. The BirdLife and Institute of Ecology and Biological Resources authors provided proof that the species was a resident breeding species in the karst limestone region of central Vietnam. The type description of the species is published in the latest issue of the Ibis, the international journal of avian science published by the British Ornithologists Union.
"The karst limestone regions of Laos and Vietnam are noted for their levels of plant, invertebrate and mammal diversity. It is however, only relatively recently that its importance for bird diversity has begun to be appreciated", said Eames.
The ranges of four bird species are now known coincide with the karst. One of these, Sooty Babbler Stachyris herberti was rediscovered in the same region of Vietnam as the Limestone Leaf Warbler by BirdLife researchers in 1994 after an absence of 64 years.
There are large areas of forested karst within the known range of the species and it is known to occur in Hin Namno National Protected Area in Laos and Phong Nha-Ke Bang National Park in Vietnam. Although the species is not believed to be under any immediate threat the conservation status of this taxon will be assessed in due course by the BirdLife Taxonomic Working Group; BirdLife will then evaluate its extinction risk category for the IUCN Red List (for which BirdLife is the official Red List Authority).
BirdLife staff Jonathan Eames and Le Trong Trai, have now been responsible, with co-workers for the discovery and description of four bird species new to science, all from Vietnam. The other three comprising Black-crowned Barwing Actinodura sodangorum, Chestnut-eared Laughingthrush Ianthocincla konkakinhensis and Golden-winged Laughingthrush Trochalopteron ngoclinhense. In addition with co-workers, they have described a further 13 new bird sub-species for science from Cambodia and Vietnam.