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Unexpected returns from a study of birds in Southwest
Guangxi karst forests
Jiang Aiwu
College of Animal Sciences and Technology, Guangxi University
Photo: Yang Hua
The warm wet conditions of southwest Guangxi have shaped a karst landscape of many small flat areas interspersed with towering limestone hills that is difficult to access and cultivate. It has very rich biodiversity and is considered to be of national, and even global, importance. Straddling the China-Vietnam border,these karst landscapes have not been a key target for systematic research in the past. But scientists have made a lot of new discoveries following more in-depth studies in recent years. Upon obtaining a KFBG Studentship grant in 2004 and with the guidance of my supervisor, Professor Zhou Fang, I undertook a comparative study of birds in karst forests.
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Prof. Zhou Fang with the reserve wardens
in Nonggang |
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Data were mainly collected by direct observation along fixed transects and by setting mist nets. The fixed-transect method was effective in recording large-bodied and canopy birds, while mist nets were useful at collecting data on secretive, understorey birds in the forests. In the three-year study I went to Nonggang, Xialei, Bangliang, Bapen, Banli, Daqingshan and Diding; these are either nature reserves or patches of well-preserved forest in southwest Guangxi. A total of 171 forest bird species were recorded. Some are rare, including the Endangered White-eared Night Heron Gorsachius magnificus, the Malayan Night Heron Gorsachius melanolophus, Blue-rumped Pitta Pitta soror, White-winged Magpie Urocissa whiteheadi and Indochinese Green Magpie Cissa hypoleuca. These birds have significant populations in karst forests in southwest Guangxi, and White-winged Magpie even occurs in good numbers in well-preserved forests. Some new records to Guangxi were made, such as the Indochina subspecies of Speckled Piculet Picumnus innominatus malayorum and Oriental Magpie-robin Copsychus saularis erimelas, Buff-breasted Babbler Pellorneum tickelli and Buff-chested Babbler Stachyris ambigua. Some recently recorded species such as White-rumped Shama Copsychus malabaricus and Large Niltava Niltava grandis were also found in this study. Nonetheless, the most unexpected find must be the discovery of Nonggang Babbler Stachyris nonggangensis, a species new to science.
Stachyris nonggangensis – a gift from
out of the blue
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Close-ups of Stachyris nonggangensis
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One afternoon in July 2005 at Nonggang Nature Reserve, when I was having a bite of compressed biscuits, two inconspicuous birds hopped slowly down from the rocks to search for food right in front of me. Subsequently, whenever there was a sunny day, these birds would appear. After a couple of encounters, we seemed to be getting more familiar with one another. However, when I read through " A Field Guide to the Birds of China", my old friends couldn't be identified. The species was brown in colour with a white, crescent–shaped patch on its face. Its behaviour and distribution were similar to Streaked Wren-babbler Napothera brevicaudata, and it would fly only short distances when disturbed; it often foraged in rock crevices, preying on snails and other invertebrates.But its appearance was distinct from
N. brevicaudata. For a long time I thought it was a wren-babbler species from Southeast Asia that was hitherto not recorded from China.
When I went back to school, I consulted Professor Zhou, who instead thought this might be a new species, and urged me to intensify the study. It was still there on my subsequent visits to Nonggang, but attempts to capture one with mist nets were unsuccessful. Even when it moved around the nets, it did not get trapped. This extraordinary bird occurs mainly in well-preserved forests with a sparse understorey but the ground has many rocks among which they hop around and search for food. In January 2006, we finally captured a pair (the holotype and the paratype) as a result of increased trapping effort. This species, like other babblers in the family Timaliidae, does not vary much in appearance or coloration between sexes. The female is slightly smaller than the male, but cannot be distinguished in the field.
Unexpected rewards
Once the specimens were collected, Professor Zhou and I quickly determined that they represented a new species of Stachyris, since they had distinctive characteristics of that genus, such as stiff quills on the forehead feathers. They were larger than other ground-foraging babblers and the species can be distinguished by size from other Chinese species. Its body length is 17cm, obviously larger than Spot-necked Babbler Stachyris striolata when observed in the field. While the behaviour was somewhat similar to that of Sooty Babbler Stachyris herberti, the white crescent-shaped patch, combined with the dark greyish-brown spots on the white throat and upper breast, distinguished it readily from Sooty Babbler. Thus we were sure the Nonggang specimens represented a new Stachyris species. We proposed the name Stachyris nonggangensis and swiftly contributed an
article on this wonderful discovery to " Auk", the journal of the American Ornithologists' Union. After a prolonged period of editing and proofreading, our article was finally accepted and published, thus becoming recognised by the scientific authorities. This is the second bird species described and named by Chinese ornithologists. Coincidentally the first, Gold-fronted Fulvetta Alcippe variegaticeps, was also from Guangxi, but this dates back to 1932.
When I first planned these surveys, I didn't intend to spend much time in Nonggang National Nature Reserve. It was Drs Michael Lau and Bosco Chan who strongly recommended that reserve to me, and assured me there was an extensive tract of well-preserved karst forest. Later I recommended they carry out their camera trap survey of mammals in this reserve and they were able to capture many species on film. We joke that we have introduced a blessed land to one another. Such a quirk of fate led to the discovery of a new species. To me, the discovery was a gift utterly out of the blue.
All photos are credited to the author, unless otherwise stated.
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