Two distinct flyways with different population trends of Bewick's Swan Cygnus columbianus bewickii in East Asia

摘要: Two of the most fundamental ecological questions about any species relate to where they occur and in what abundance. Here, we combine GPS telemetry data, survey data expert knowledge for first time define two distinct flyways (the East Asian Continental West Pacific flyways), migration routes abundance Eastern population Bewick’s Swan Cygnus columbianus bewickii . The is largest flyway population, supporting c 77% numbers globally. showed that birds breeding Russian arctic from Yamal Peninsula c. 140°E (including Lena Yana Deltas), winter middle lower reaches Yangtze River China (which label “East flyway”). Swans Indigirka east Koluchin Bay Japan, mostly Niigata, Yamagata Ishikawa Prefectures “West There was no overlap used by tagged individuals flyways. Counts during 21st century have shown wide between-year variations, reflecting incomplete coverage earlier years. this currently 65,000 based on extensive wintering coverage, compared 81,000 early 2000s, less complete coverage. Chinese-wintering swans now concentrate mainly ( 80%) at Poyang Lake Jiangxi Province Hubei Lakes (mostly Longgan Lake), a more widespread distribution both within throughout Auhui 2004 2005. In contrast, 40,000, just 542 1970. This has significant overall change since 2004, when it numbered 45,000 birds. Small probably also South Korea. These results provide our basic understanding Chinese- Japanese-wintering relation their areas, confirming need coordinate future research monitoring flyways, as well information