The feeding ecology of the swan goose (Anser cygnoides) and the white-fronted goose (A. albifrons albifrons) overwintering at Poyang Lake, the largest freshwater lake in China, was studied from 1990 to 1991. The daily patterns of these geese showed differences of the activity categories between species. The energy intakes of these geese were estimated by fecal analysis, daily dropping counts, and calorie determinations. The average daily digestible energy intakes of these geese were about twice their basal metabolic rate. Roots ofVallisneria asiatica, Acorus calamus, andCatessp. were the main food for the swan goose. The leaves ofCarexsp. were the main food of the white-fronted goose. The diets of the geese do overlap with those of some other waterbirds, mainly that of the Siberian crane (Grus leucogeranus) in Poyang Lake. This, however, is not a main reason for the decrease of the number of geese in winter in this season.