responsibilities of CBK during the long voyage, James Hines, Brett 

 Hoover, and Lois Loges for computer programming assistance, and 

 Bonnie J. Fancher for help in manuscript preparation. The paper 

 benefitted from the comments of D. Ainley. W. King, and P. Gould. 



AKK thanks the other members of the ICBP 1990 Line and 

 Phoenix Islands Expedition (M. and A. Garnett, G. Wragg. J. Phillips, 

 and M. Linsley ) for use of our collective at-sea data. She also extends 

 special thanks to Mr. O'Connor for financial support during preparation 

 of the manuscript. 



On the Soviet side, it is a great pleasure to thank Professor 

 Alia V. Tsyban, Goskomgidromet, who as leader of the expedition 



provided help, interest, friendship, and outstanding hospitality during 

 the voyage. Captain Oleg A. Rostovtsev and his crew (especially the 

 navigators) of the R/V Akademik Korolev provided an excellent 

 observation platform and abided our frequent imposition for position 

 fixes from their satellite and Loran C navigation systems and 

 hydrographic charts. Yevgeniy N. Nelepov and Yuri L. Volodkovich 

 provided much assistance during the voyage, and Boris Sirenko and 

 Boris Alexandrov willingly shared their knowledge of benthic and 

 pelagic organisms. Our contacts with our Soviet colleagues would 

 have been far less stimulating without the translation skills of 

 Valeriya M. Vronskaya and Svetlana V. Petrovskaya. 



3.6 Evidence for a Major Fall Land Bird 



Migration Corridor Across the South China 

 Sea from Indo-China to the Greater Sunda 

 Islands 



DAVID H. ELLIS. ANGELA K. KEPLER, and CAMERON B. KEPLER 



US Fish & Wildlife Senice, Patu.xent Wildlife Research Center, Laurel, Maryland, USA 



Introduction 



Until 1960, bird migration corridors in eastern Asia were 

 poorly known (Wetmore, 1926; Delacour, 1947; McClure, 

 1974; Medway & Wells, 1976). In southeast Asia, however, 

 the geography of the land masses surrounding the South China 

 Sea seems to create natural funnels that should concentrate 

 migrant land birds into three primary fall corridors. Important 

 flight paths along some of these routes have recently been 

 discovered. 



It is known that migrants from Japan and eastern China 

 island-hop south through the Philippines (Wetmore. 1926; 

 McClure, 1974), with Ng ( 1978) presenting evidence that barn 

 swallows (Hirundo rustica) move directly from mainland 

 China to the Philippines. McClure ( 1974) asserted that many 

 migrants passing through the Philippines to Borneo fly west 

 from Palawan, then south to Borneo. Simpson (1983a,b) 

 encountered hundreds of migrant birds at the Tembungo offshore 

 oil drilling platform near the northeastern tip of Borneo (Fig. 1 ) 

 during the fall migration of 1981. Although he reported these 

 observations as evidence of a passage directly across the South 

 China Sea, his location near Balabac Strait also suggests that 

 these migrants could have been moving south from the 

 Philippines. 



Geography suggests that many migrant land birds in 

 Burma and western Thailand would move south along the 

 Malay Peninsula, a pathway known to be important ( McClure, 

 1974; Medway & Wells, 1976; Hails, 1987), and thence across 

 the narrow Straits of Malacca to Sumatra. However, migrants 

 from east Thailand as well as those from China, Laos, and 



Vietnam, moving down the Indo-China Peninsula would 

 naturally converge south of the Mekong River Delta on 

 Mui Bai Bung. From this tip of the Indo-China Peninsula, 

 birds traveling overland must fly northwest into Thailand 

 before proceeding south. Those capable of a relatively short 

 (ca. 400 km) overwater flight can fly southwest across the Gulf 

 of Thailand toward the Malay Peninsula, a route portrayed by 

 McClure (1974) and Hails (1987) as a minor pathway for the 

 migrants from Indo-China. 



McClure (1968, in McClure, 1974) illustrated a coastal 

 migration route from Taiwan to northern Vietnam, thence 

 south, crossing the South China Sea to Borneo, another route 

 suggested by geography. However, he provides scant evidence 

 for such a corridor and no evidence that migrants are 

 concentrated at Mui Bai Bung. McClure ( 1 974) discussed a fall 

 passage of willow warblers (Phylloscopus sp.) across the South 

 China Sea to Sarawak without offering details on their point of 

 origin north of the sea. Simpson (Wells, personal 

 communication and in prep.) reported a substantial fall 

 movement of land birds ( 36 species ) in the Terengganu oil field 

 (ca. 05°25'N, 105°13'E, see Fig. 1 ). Although this location is 

 only about 200 km east of the Malay Peninsula and west of a 

 direct route to Borneo, Simpson's records provide the best 

 evidence to date of a direct South China Sea crossing. The birds 

 observed by Simpson (1983a) at the Tembungo oil terminal 

 could have come from Vietnam, as he suggests, but the source 

 of these migrants is clouded by their proximity to the Philippines. 

 Although biologists from the Chinese Academy of Science and 

 the Beijing Natural History Museum (Anon., 1974) noted 

 44 species of land birds during 1974 surveys of islets in the 



247 



