Isotopic niches of the Northern shoveler Spatula clypeata in spring migratory stopover sites in the Marais breton, France.

The Northern shoveler, Spatula clypeata, makes several migratory stopovers to reach its breeding site in the best conditions. These stopovers allow the species to replenish their reserves. Therefore, feeding efficiency at such sites is essential. Despite its importance, few studies have been conducted on the spring ecology of the shoveler, particularly on its diet at stopover sites. Therefore, this study focused on the Northern shoveler's feeding habit during its spring migratory stopover in the Marais breton (MB), a wetland situated in Vendée (France, Atlantic coast). The shoveler's plasma and potential food resources were studied using a stable carbon and nitrogen isotope analysis. The study showed that the shoveler feeds primarily on microcrustaceans, especially Cladocera and Copepoda; Chironomidae larvae, Corixidae, Hydrophilidae larvae, and particulate organic matter. This last food source, the POM, had never been highlighted before.