05 June 2009

Research on Status of Whistling Thrush Taxa in Peninsular Malaysia

A research project on three types of whistling thrushes is underway in Peninsular Malaysia, being conducted by Dr. Shahrul Anuar bin Mohd Sah, of the School of Biological Sciences at Universiti Sains Malaysia, Lim Kim Chye and David Bakewell.

Blue Whistling Thrush. Image courtesy of David Bakewell.

”Malayan Whistling Thrush is one of very few species truly endemic to Peninsular Malaysia, and yet it is poorly known," said Bakewell. "Until recently it was assumed that it was separated ecologically from Blue Whistling Thrush by altitude, but our research has already proved that this assumption is false. We currently have almost no knowledge of how these two taxa function when occurring sympatrically.

"Our suspicion is that these birds are far more restricted in range (and therefore threatened?) than currently recognized. In addition, rising temperatures over the last couple of decades may have had negative impacts on the taxon (including possible increased competition with the larger Blue).

"The fact that most birders do not realize how similar dicrorhynchos Blue is plumage-wise to Malayan continues to muddy the waters, so it is vital that sound criteria are found and publicized by which to differentiate the two taxa, as a prerequisite to determining the real status of the endemic species.”

The “assessment aims to clarify the status of these taxa in relation to one another by means of mist-netting (enabling detailed measurements, plumage description and samples for DNA analysis to be taken), field observation, photography and sound recording,” according to a project summary.

Three types of nonmigratory taxa are to be studied:

  • The Malayan Whistling Thrush (Myophonus robinsoni) is a montane species endemic to Peninsular Malaysia.
  • The closely similar near-endemic dicrorhynchus race of Blue Whistling Thrush (M. caeruleus) occurs in southern Thailand, central and southern Peninsular Malaysia, and parts of Sumatra, Indonesia
  • The crassirostris race of Blue Whistling Thrush, occurs in Langkawi and Perlis, as well as South-east Thailand and Cambodia.

The field research is being done at 1) Cameron Highlands, where Malayan and Blue Whistling Thrushes possibly co-exist; 2) Fraser’s Hill, where the Malayan Whistling Thrush is known to occur; 3) Kinta Valley, where only the Blue Whistling Thrush is known to occur, and 4) Perlis State Park, where the crassirostris race of Blue Whistling Thrush is regularly recorded.

"Since whistling thrushes favour steep-sided mountain streams as feeding areas, getting to some of the netting sites along river banks and across streams and small rivers has been quite a challenge," Bakewell said. "We have to keep an eye on water levels, as rain upstream can cause water levels to rise quickly and currents to become treacherous."

The researchers hope to develop “clear field identification criteria” to readily distinguish the Malayan and Blue Whistling Thrushes in the normal conditions when the species are typically observed.

Baseline data which is collected will provide “an up to date assessment of the conservation status of these taxa in Peninsular Malaysia for BirdLife International,” and “follow-up conservation plans to be drawn up for threatened taxa in Peninsular Malaysia.”

The species which are the focus of the study will be the primary beneficiaries, as increased understanding of their status will hopefully lead to more and better focused effort on their conservation.

"It has been heartening that the response of local people has been firstly, concern, in case we intend to harm or keep the birds we catch, and then, when they understand the purpose of our research, they express interest and are highly cooperative," Bakewell said. "One of our netting sites is in the grounds of an active Buddhist temple, and another in a woodyard. The staff of both are appreciative and protective of ‘their’ birds, which bodes well for their continued well-being."

“Local environmental NGOs, such as the Malaysian Nature Society and the World Wide Fund for Nature, will benefit from greater information on the status of these taxa, enabling them to design more effective conservation strategies.”

Information on where to best observe these species will assist in developing local bird tours.

The Whistling-Thrush Project is funded by Malaysian Nature Society Perak Branch through the Tan Kean Cheong Bird Conservation Memorial Fund. Fieldwork for the Project started in April and will run until October 2009.

Updates, including photographs of the study locales, are being provided online by David Bakewell on a regular basis. This blog includes a wide variety of fine photographs of local places, and their native fauna, especially birds.

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