Abstract
The esophageal and gizzard contents of wintering Northern Shovelers (Anas clypeata) in the hypertrophic Lake Teganuma were analyzed to ascertain their feeding habits. Seven ducks were captured in March 1991 using a Japanese traditional hunting method (Nagashi-mochi-nawa). Their esophageal and gizzard contents were removed immediately, fixed with formalin and observed under a microscope. No identifiable contents were found. However, the major contents of the gizzard were cyclopoid copepodids and an attached green alga Cladophora glanurata, plus an insignificant number of rotifers Brachionus calyciflorus, B. leydigii, B. angularis, Trichocerca birostris and Polyarthra spp., as well as nematodes Nematoda spp. and attached diatoms Navicula spp. and Synedra spp..
