Ecological aspects of the feeding behaviour of two calidridine sandpipers wintering in south-eastern Tasmania

Abstract

Calidris ferruginea and C. ruficollis are congeneric species wintering in the same tidal habitat. They do not compete when most densely concentrated during the early stages of the ebb, because C. ferruginea forages usually below the waters edge and C. ruficollis above it. Also C. ferruginea gets most of its food at a greater depth below the substrate surface. That ecological separation does not necessarily give rise to dietary differences is shown by the broad overlap of the items found in the stomachs. This applies to size and species of food-item. Both C. ferruginea and C. ruficollis are largely opportunistic feeders, eating all suitable items encountered within a narrow range of size.