Composition of spring waterbirds in coastal wetlands along the Bohai and Yellow Seas of China and comparison of the number of individuals in different areas

To further investigate the numbers, species, and distribution of waterbirds during their spring migration, a coordinated survey was conducted in April 2023 across 25 wetlands along the Yellow Bohai Sea coast. This survey, carried out in collaboration with 30 organizations, employed a combination of line transects and point count methods. A total of 1 115 772 waterbirds from 126 species, belonging to 8 orders and 18 families, were recorded. Among these, shorebirds accounted for the highest number of individuals, with 855 485 individuals, representing 76.67% of the total population. Among the 126 waterbird species recorded, 12 were classified as national first-class key protected species, and 20 as second-class key protected species. Additionally, 44 species of waterbirds accounted for more than 1% of their global populations based on individual numbers. The highest numbers of waterbird individuals were recorded in the Liaoning Liaohekou Wetland, Jiangsu Yancheng Wetland, Shandong Yellow River Delta Wetland, and Liaoning Dandong Yalujiangkou Wetland. Among these, Jiangsu Yancheng Wetland had the greatest species diversity, with 107 species identified. The wetlands were assessed based on Criteria 5 and 6 of the Convention on Wetlands of International Importance. Of the surveyed wetlands, 23 met either Criterion 5 or Criterion 6, accounting for 92% of the total area, while 15 wetlands met both Criteria, representing 60% of the surveyed area. However, 10 wetlands have not yet been included in the national wetland protection system.