Mekong Wagtail: the great river's only known avian endemic: 2 Lessons to be learned from the 'discovery'
The chronology of events leading this wagtail's 'discovery' provides us with some useful lessons in ornithological rigour. In summary, it transpires that the bird was in fact first collected back in December 1972, on a tributary of the Mun river, Ubon Ratchathani Province, north-east Thailand. These specimens, now held in the Thailand Institute of Scientific and Technological Research, Bangkok, (TISTR) were used to illustrate the form of White Wagtail M. a. alboides in Lekagul and Round's A Guide to the Birds of Thailand.(15) Wagtails roughly conforming to this illustration were found on numerous occasions during surveys in Laos between February 1993 and late 1999 (16,17,20,21) and in 1997 were suspected to breed in southern Laos (PD unpublished data). When security problems in Cambodia eased in the late 1990s, surveys also began to find this wagtail breeding widely along the Mekong and its larger tributaries in the north-east of the country.(19,22) M. a. alboides breeds no closer than northern Vietnam23 and north Laos.(16,20) Thus, these records would have represented a major extension of the form's known breeding range. However, they in fact generated minimal interest because a) they apparently fitted a known taxon portrayed in an excellent field guide, and b) attention was focused on scarcer, declining river channel specialists, thus the relatively numerous wagtails seemed of no elevated conservation concern. As a consequence, sightings of black-and-white wagtails were frequently incompletely documented, and, most importantly (in hindsight), not ascribed to recognisable subspecies. This has resulted in our current lack of knowledge over the species's range limits, specifically its northern limit along the Mekong, how far up some of her larger tributaries the species occurs, and indeed how abundant it is in southern Laos. It was not until Robson's Field Guide to the Birds of South-East Asia (9) was published, which accurately illustrates M. a. alboides (as indeed does Grimmett et al.'s Birds of the Indian Subcontinent (6)), showing it to be quite distinct from the breeding wagtail of southern Indochina, that the penny finally dropped. Had museum collections been more comprehensively consulted from the outset (skin-checking was in fact thorough, but probably only covered a third or so of all species recorded), the bird's identity would likely have been determined some years ago. Where to see Mekong Wagtail
Two of the most accessible areas to see the species are in Cambodia, one along the Mekong mainstream at Kampi, just north of Kratie, the other along the lower Kong and San rivers just upstream of Stung Treng. Daily passenger boats depart Phnom Penh for Kratie (journey time five hours), and a half hour moto-taxi ride upriver from the town will bring you to Kampi, where numerous boats are available for hire. Kampi is also the most accessible (and best known) locality to see Irrawaddy Dolphin Orcaella brevirostris along the Mekong in Cambodia. Several pairs of wagtails inhabit the channel mosaic extending for 2-3 kms upstream of the deepwater pool favoured by the dolphins during the dry season. At least three return flights a week operate between Phnom Penh and Stung Treng, where again it is easy to find a boat to hire and either take upstream a couple of kilometres, from where the wagtail is common - one of the best stretches of river is along San just upstream of its confluence with the Kong, or head downstream into the Mekong main channel and explore the mosaic habitat both up and downstream of the Mekong/Kong confluence. Alternatively, the stretch of the Mekong main channel in extreme southern Laos between Khon Falls and the Cambodian border is another good place to look, this area also supporting several Irrawaddy Dolphins. Acknowledgements
We extend our sincere gratitude to Per Alström, Rob Timmins and Tom Evans for technical assistance in describing the wagtail, Tan Setha for logistical expertise and his effervescent company during recent survey work in Cambodia. Grateful thanks also to the Royal Government of Cambodia's Department of Forestry and Wildlife, Ministry of Agriculture, Forestry and Fisheries, and the Lao PDR Government Department of Forestry's Centre for Protected Areas and Watershed Management for their invaluable assistance in all manner of areas during the course of recent surveys in the two countries, and in particular the Wildlife Conservation Society Lao and Cambodia programmes, under which much of the work has been carried out. See the Bulletin of the British Ornithologists Club (1) for comprehensive acknowledgements pertaining to the type description of the wagtail and all those contributing information/expertise. References -
Duckworth, J. W., Alström, P., Davidson, P., Evans, T.D., Poole, C.M., Tan Setha & Timmins, R.J. 2001. A new species of wagtail from the lower Mekong basin. Bull. British Ornithologists' Club 121 (3): 152-182. -
Poole, C.M. 2000. Obituary: Sam Veasna. Bull. Oriental Bird Club 31: 8. -
Alström, P., Mild, K. & Zetterström, B. In press. Pipits and Wagtails of Europe, Asia and North America. London: Christopher Helm/A&C Black. -
Brazil, M. A. 1991. The Birds of Japan. London: Croom Helm. -
Ali, S. & Ripley, S.D. 1998. Handbook of the Birds of India and Pakistan. Vol. 9. 2nd ed. Delhi: Oxford University Press. -
Grimmett, R., Inskipp, C. & Inskipp, T. 1998. Birds of the Indian Subcontinent. London: Christopher Helm / A&C Black. -
Keith, S., Urban, E. K. & Fry, C. H. 1992. The Birds of Africa, vol IV. London: Academic Press. -
Duckworth, J. W., Timmins, R. J. & Evans, T. D. 1998a. The conservation status of the River Lapwing Vanellus duvaucelii in southern Laos. Biological Conservation 84: 215-222. -
Robson, C. 2000. A field guide to the birds of South-East Asia. London: New Holland. -
Urban, E. K., Fry, C. H. & Keith, S. 1986. The Birds of Africa, vol II. London: Academic Press. -
Thewlis, R. M., Timmins, R. J., Evans, T. D. & Duckworth, J. W. 1998. The conservation status of birds in Laos: a review of key species. Bird Conservation International 8 (suppl.): 1-159. -
Duckworth, J. W. 1997. Observations on a population of Jerdon's Bushchat Saxicola jerdoni in the Mekong channel, Laos. Bull. British Ornithologists' Club 117: 210-220. -
Duckworth, J. W., Davidson, P., Evans, T., Round, P. D. & Timmins, R. J. in press. Bird records from Laos, principally the upper Lao Mekong and Xiangkhouang Province, in 1998-2000. Forktail. -
Hirsch, P. & Cheong, G. 1996. Natural resource management in the Mekong River basin: perspectives for Australian Development Cooperation. AusAID/University of Sydney, Sydney, Australia. -
Lekagul, B. & Round, P. D. 1991. A guide to the birds of Thailand. Bangkok: Saha Karn Bhaet. -
Duckworth, J.W., Davidson, P. & Timmins, R.J. 1999. Birds (pp.69-159) in Duckworth, J. W., Salter, R. E. and Khounboline, K. (compilers) Wildlife in Lao PDR: 1999 Status Report. Vientiane: IUCN-
The World Conservation Union/Wildlife Conservation Society/Centre for Protected Areas and Watershed Management. -
Evans, T. D., Towll, H. C., Timmins, R. J., Thewlis, R. M., Stones, A. J., Robichaud, W. G. & Barzen, J. 2000. Ornithological records from the lowlands of Southern Laos during December 1995 - September 1996, including areas on the Thai and Cambodian borders. Forktail 16: 29-52. -
Dudgeon, D. 2000. Large-scale hydrological changes in tropical Asia: prospects for riverine biodiversity. BioScience 50: 793-806. -
Timmins, R. J. & Men Soriyun. 1998. A wildlife survey of the Tonle San and Tonle Srepok river basins in north-eastern Cambodia. Fauna & Flora International and Wildlife Protection Office, Hanoi and Phnom Penh. -
Duckworth, J. W., Evans, T. D., Robichaud, W. G., Thewlis, R. M., Timmins, R. J. & Tizard, R. J. 1998b. Bird records from Laos, October 1994-August 1995. Forktail 13: 33-68 (including errata sheet distributed with Forktail 14). -
Evans, T. D. & Timmins, R. J. 1998. Records of birds from Laos during January-July 1994. Forktail 13: 69-96. -
Duckworth, J.W., Poole, C.M. & Van Zalinge, N.J. in prep. Bird Observations from the Mekong and major tributaries in North-east Cambodia, 1998-2000. -
Vaurie, C.H., White, C.M.N., Mayr, E. & Greenway, J.C., Jnr. 1960. Family Motacillidae. In Mayr, E. and Greenway, J. C., Jr. (Eds) 1960. Checklist of Birds of the World, vol. 9. Pages 129-167. Museum of Comparative Zoology, Cambridge, Mass., U.S.A. |
