The database ‘data_sites.txt’ contains data on the sites used by the 15 Northern shoveler in prenuptial stopover i.e. data on the wetland used (Marais breton or Marais poitevin), the site area (in ha), the vegetation (in % of cover), the physico-chemistry of the water (water and sediment level in cm, salinity), the total density and the density of each taxon of freshwater invertebrate (in individual number / m3).