Sitting ducks: diet of wintering wildfowl in Lake Tonga, northeast Algeria

Dietary studies of five species of Anatidae (Gadwall Anas strepera, Shoveler Anas clypeata, Pochard Aythya ferina, Ferruginous Duck Aythya nyroca, and White-headed Duck Oxyura leucocephala) were carried out at Lake Tonga, northeast Algeria, from December 2011 to March 2012. Diet analysis of all five wintering species indicated a heavy reliance on seeds, which included a wide variety of aquatic plants, such as Myriophyllum spicatum, Ceratophyllum demersum, Sparganium erectum, Scirpus lacustris and Potamogeton pectinatus. Noteworthy is the paucity of ingested macroinvertebrates. Despite dietary overlap, the type, abundance and frequency of food consumed clearly indicated differences in resource use among the ducks. Incidentally, the study also highlighted the high vulnerability of threatened ducks to poaching (harvesting and disturbance) in a protected area. We discuss the implications of these findings for the management and conservation of wintering wildfowl and their North African habitats.