Occurrence dataset from the waterbird survey of the middle and lower Huai He floodplain, China.

Background: The Huai He floodplain in Anhui and Jiangsu Provinces, an important component of the East Asian-Australasian Flyway (EAAF), sustains critical wetland habitats for migratory waterbirds, including four threatened species on the IUCN Red List: critically endangered Aythyabaeri (Radde, 1863), endangered Ansercygnoides (Linnaeus, 1758) and vulnerable Melanittafusca (Linnaeus, 1758) and Aythyaferina (Linnaeus, 1758). Despite its biogeographic significance as a transitional zone between the Yangtze and Yellow River floodplains, this region remains one of China's most understudied and ecologically degraded freshwater systems. Historical pollution events and contemporary anthropogenic pressures - agricultural intensification, hydrological fragmentation and invasive species - have severely compromised wetland integrity. During mid-December 2005 and November to December 2006, standardised surveys employed fixed-radius point counts (158 sites) with the component counting method to enhance accuracy.

New information: We present the first comprehensive waterbird dataset for the Anhui and Jiangsu part of the Huai He floodplain, comprising 44 species (32,517 individuals) recorded across 30 wetlands during 2005-2006 surveys. All occurrence data adhere to Darwin Core standards and are accessible via the Global Biodiversity Information Facility, providing spatial-temporal baselines for abundance and distributional data for waterbirds in this region.