Little-known Oriental Bird: Courtois's Laughingthrush

by Hong Yuan-hua, He Fen-qi, Roland Wirth, David Melville, Zheng Pan-ji, Wang Xia-zhi,Wang Gui-fu and Liu Zhi-yong, from OBC Bulletin 38, December 2003.

After seven years of effort, Courtois's Laughingthrush Garrulax galbanus courtoisi, hitherto only known from two museum specimens collected in 1919, was 'rediscovered' in 2000 at its type locality, Wuyuan, Jiangxi Province, China. Unlike most other Laughingthrushes studied to date, Garrulax galbanus courtoisi nests in loose colonies. More intriguing still, is that despite intensive survey efforts covering all types of habitats, the bird has so far only been found in stands of old village trees, which villagers in this part of China have protected for generations. Only some 150-160 surviving birds are known to date, making this taxon one of the rarest birds in the world. A bird whose survival up to now and well into the future may be dependent on a regional tradition of protecting old village trees.

Efforts, both domestic and international, to rediscover Courtois's Laughingthrush, a subspecies of Yellow-throated Laughingthrush Garrulax galbanus, at its type locality have continued for years but have now finally shown some dramatic and positive results. Furthermore, data recently obtained on the status and breeding behaviour of this heretofore unstudied bird is demonstrating to us something more than mere taxonomy.

For the whole story of the discovery of the bird, a British topographical surveyor, Colonel Godwin-Austen, constitutes the very beginning. In 1874, Colonel Godwin-Austen described a new species of laughingthrush, Garrulax galbanus, based on skins he obtained in February 1873 in the Munipur valley, eastern Assam, India, (1) from which area the species is now mostly known by its English name, the Yellow-throated Laughingthrush. Later on, in 1923, M. A. Ménégaux, President of the Société Ornithologique de France, recognised another laughingthrush species, Garrulaxcourtoisi, based on two bird skins collected in September 1919 by a French missionary Père A. Riviere, from Wuyuan in south-east China and sent to him by Père F. Courtois. (2,3) And, although the direct distance from Munipur to Wuyuan is at least 2000 kilometres, and no record of either of the two birds had been reported at any site between the two localities at that time, courtoisi was nevertheless soon after relegated to the status of a subspecies of Garrulax galbanus. (4) More than half a century then passed before in 1982 two Chinese ornithologists, Prof. Cheng Tso-hsin and Tang Rui-chang, described one more subspecies of galbanus, and since the three specimens were collected at Simao in Yunnan Province, south-west China, the new subspecies was named simaoensis. (5) Therefore, three subspecies of the Yellow-throated Laughing-thrush have so far been recognised - the nominate form distributed in the area where the Indian sub-continent meets Indochina, and the other two in mainland China. Although Simao lies more or less between Munipur and Wuyuan, it is apparent that the Yellow-throated Laughingthrush shows a completely allopatric pattern in the ranges of its three subspecies. (6,7)

It is now known that the nominate form, whose type locality is Munipur, can also be found in a relatively large surrounding area, including the Chin Hills of western Myanmar (Burma) and also as far afield as a small area in southern Bangladesh. (8,9) According to Smythies, it is locally 'a common breeding bird of the Chin Hills at 5,000-6,000 feet from mid-April to early June'. (10,11) In contrast, nothing new came to be known of either a geographical or ethological nature about the two Chinese subspecies. In fact, until our recent success, no-one, neither professional ornithologist nor keen bird watcher, had reported having so much as seen a courtoisi or simaoensis, whether in their type localities or elsewhere, since the type specimens were collected in 1919 and 1956, respectively. This implied that they were restricted to a rather small area, and/or in a rather specific habitat, and/or had been reduced to very small surviving numbers - all of which have proven to be true for courtoisi. Simaoensis has yet to be rediscovered. It should be noted, however, that their elusiveness in the wild notwithstanding, there are several populations of Yellow-throated Laughingthrush in European collections, which apparently are self-sustaining, (11) and some bird keepers believe that the birds they have are of the subspecies simaoensis. (12) If the birds are simaoensis, it is far from clear how they could have reached Europe, and from whence they came. An exhaustive search of all original customs documents relating to passerine birds exported from China revealed no record of Yellow-throated Laughingthrush.

When, in the early 1990s, concern as to the status of the two forms of the bird occurring in mainland China grew, the German conservation organisation Zoologische Gesellschaft fur Arten und Populationsschutz (ZGAP) provided some small grants to their Chinese colleagues to investigate the status of wild populations of the bird, hopefully including both courtoisi and simaoensis. It required successive field surveys over a period of seven years before courtoisi was finally rediscovered in the wild in Wuyuan, Jiangxi during the 2000 breeding season.

During our field observations in 2000, a total of 80-90 birds was counted, which were found in two breeding flocks approximately 40 km apart. Although we obtained some basic ethological knowledge and a rudimentary understanding of the breeding biology and habitat selection of the bird, all we could really say about the current status of this taxon was that it was extremely rare, leaving many uncertainties. However, following fieldwork in 2001, when two more breeding sites of courtoisi were found, a relatively more integrated picture has emerged, making it possible to outline, even if still only sketchily, the breeding range and status of the bird in Wuyuan County.

Briefly, the birds are found at an altitude of less than than 100 m, breeding in flocks, choosing their breeding sites close to a river, nesting in the canopy of big trees, and all four breeding flocks found to date are situated around villages, and very close to villagers' houses. This close association between the birds and human habitation is remarkable. It is well established that most laughingthrushes nest in bushes, shrubs, or tall grasses rather than large trees, and breed in relatively isolated pairs rather than colonies, as indeed is reported for nominate galbanus. (13) But courtoisi seems to confound all that we thought we knew about laughingthrushes. In fact, although we had thought we had surveyed all the potential habitats available for this laughingthrush in Wuyuan County in previous years, we failed to find any trace of the bird. However, while we were counting and identifying the large, old trees occurring around villages in 2000, the bird was suddenly and very surprisingly, right in front of us!

In our 2001 field season, more than 20 courtoisi nests were located, and all of them were sited in the canopy of mature trees. The trees the birds mostly favour as nesting sites are the Chinese Sweet Gum Liquidambar formosana/taiwaniana and the Camphor Cinnamomum camphora, while others include Pterocarya stenoptera, Aphananthe aspera, and the conifer Cunninghania lanceolata. It therefore appears that these centuries-old large trees are providing crucial, if not indeed obligate, habitat for the continued successful reproduction of this rare bird.

Geo-morphologically, Wuyuan County's landscape consists mainly of montane areas rising from 35 m at the base of hills to over 1,600 m at the mountain tops. The small basins and plains lower than 200 m are quite heavily populated. Today over 70% of the county is still covered by forests and woods, albeit these are rarely original but rather secondary forest or even plantations. It can be safely inferred that in the past there were much more extensive primary sub-tropical evergreen forest and wood communities present. It appears that Courtois's Laughingthrush needs large, mature trees which formerly must have been common, as presumably was this taxon. Considering other features of the breeding habitats that courtoisi seems to require, such as a low altitude and proximity to a river, the conclusion might be drawn that, in present times in Wuyuan, only the outskirts of villages can satisfy all of the species's requirements.

It is a pity that in his original paper describing Garrulaxcourtoisi, Ménégaux failed to mention the exact location, or at least the type of habitat, or even the altitude from which the two skins were collected. Nevertheless, considering the difficulties of travel in 1919 when Père Arnous was visiting Wuyuan, the two birds would more likely than not have been obtained at a site not very far from the central town of the county, or at least along, or close to, the old countryside road, though the intrepid Father may had ventured further afield in his botanical quests. La Touche quotes Courtois as saying that the birds 'frequented brushwood in flocks, fairly numerous but wild'. (3)

It is noteworthy that Courtois' Laughingthrushes breed at so low an altitude, especially when compared with the the nominate form, which usually lives well above 1,000 m in India. (10,11,14,15,16) It is interesting to speculate whether the subspecies courtoisi has evolved some form of obligate relationship with human settlements during the breeding season, or whether their current breeding sites are simply a consequence of the fact that the only large, old trees now left occur around villages.

Our censuses in Wuyuan in 2000 and 2001 found 80-90 birds in two flocks, and 150-160 individuals in four flocks respectively. Quite possibly, there are more breeding sites in Wuyuan that we have not yet found. Even if this proves to be the case, however, our best estimate would still put the total population at probably fewer than 1,000 individuals, but conceivably up to a maximum of 1,500 although this is considered to be unlikely - if heretofore undiscovered flocks are utilising the same breeding habitats as the four already located. Such a small likely total population size is a matter of concern.

The species Garrulax galbanus, when treated as a whole, is globally classified as Near Threatened (NT). (17,18) However, this categorisation seems more likely to be based entirely on the nominate form, galbanus, which occurs in a much larger range than its Chinese conspecifics and at a minimum of 16 separate known locations. (9) Even though the available data on courtoisi are still quite limited, enough is known to draw some tentative conclusions as to its status - given the fact that the known birds are now totally in one local population, with 150-160 individuals and in one small area only. In accordance with the latest version of the IUCN Red List Criteria 2000, (17) the subspecies courtoisi certainly qualifies as Endangered (EN), and quite possibly even Critically Endangered (CR), given its presumed population size and the range it actually seems to occupy. For example, of the four breeding sites of this taxon which have been located, none is larger than 10 ha in total size, which shows how phenomenally circumscribed the breeding territory of this relict subspecies has become.

The results of our exhaustive field searches reveal that the first, and for a long time also the only, record of Courtois's Laughingthrush, though nearly a century old, is by no means an incidental one. There has evidently long been a very small, remnant population of the bird tenaciously surviving in Wuyuan - and only Wuyuan.

In the last 10 years, the local authorities and government in Wuyuan County have been making constant efforts in conservation, including the delimiting of so-called Mini-Protected Areas (MPAs), with ranges varying from a few hectares to hundreds of hectares or even more. When field studies on courtoisi were initiated, more than 180 MPAs had already been established, which cover a remarkable portion of the territory of Wuyuan and should bode well for the future of the birds. For instance, the first two breeding groups we found were both in MPAs. One MPA, no larger than 5 ha in total, not only supports courtoisi but also has a bird community of fairly high diversity. Other breeding species include: Mandarin Duck Aix galericulata, Grey-capped Pygmy Woodpecker Dendrocopos canicapillus, Dollarbird Eurystomys orientalis, Asian Barred Owlet Glaucidium cuculoides, Oriental Turtle Dove Streptopelia orientalis, Black Baza Aviceda leuphotes, Chinese Sparrowhawk Accipiter soloensis, Pied Falconet Microhierax melanoleucos, Long-tailed Shrike Lanius schach, Grey Treepie Dendrocitta formosae, Black-naped Oriole Oriolus chinensis, Ashy Drongo Dicrurus leucophaeus, Eurasian Blackbird Turdus merula, Oriental Magpie Robin Copsychus saularis, and Red-billed Starling Sturnus sericeus. Some of these are also considered to be threatened bird species.

There is still much to be learned, both about and from, this small population. For example, we still know nothing about where they go and what they do during the long non-breeding season. As soon as nestlings fledge all the birds, both adult and young, leave their breeding sites, disappearing into the low hills. And as to what we can learn from this pertinacious laughingthrush, perhaps most importantly it will afford us an excellent opportunity to study the long-term viability, genetic and otherwise, of such an extremely diminutive and tightly circumscribed population. The rediscovery of courtoisi in the wild in Wuyuan also teaches us something of the true significance of Mini-Protected Areas for local/regional conservation efforts. With the support of the World Wildlife Fund (WWF) China Program, two more MPAs are being designated and will soon be in operation. Run jointly by the local authority and with the involvement of the local community, these two new MPAs will raise the hope of ensuring the well-being of all four breeding flocks.

We cannot conclude without mentioning the uncertain taxonomic position of the bird. We find this ever more confusing, but yet something that must certainly be tackled in the future. Perhaps ethological differences from the nominate form will prove more salient than morphological considerations in determining the most logical taxonomic status of this seemingly unique laughingthrush. Knowing and keeping all that in mind, the subspecies simaoensis will definitely be our next target. For us, these two endemic Chinese taxa remain a mystery, and a challenge.

Acknowledgements
We would like to thank Zoologische Gesellschaft für Arten- und Populationsschutz e. V. (Germany), the Oriental Bird Club (UK), Chester Zoo (UK), Leeds Castle Bird Garden (UK) and the Forestry Bureau of Wuyuan County (China) for funding this study and ongoing work to conserve the species. Sir Anthony Galsworthy, former British ambassador to Beijing and deeply committed to the conservation of Chinese biodiversity, is thanked for improving the English of an early draft of this paper. Our final thanks go to those villagers of Wuyuan county who, for generations, have vigorously protected the large trees in and around their villages, and as such are responsible for the survival of a subspecies of bird which might otherwise already have gone extinct.

References

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