Fig. 1

Migration route of the water birds from South China to North China (A) and three sampling sites in Caofeidian district (B) and Hangzhou Bay (C). Three sampling sites in each region are indicated in red. Green bands: migration route of water birds in the coastal region of China. The migratory information comes from International Union for Conservation of Nature, IUCN. The sampling sites were mapped by the ArcGIS Desktop 10.2 software (http://desktop.arcgis.com/)