Feeding Ecology of Wood Ducks in South Carolina

Abstract

Wood ducks (Aix sponsa) were studied from August 1973 to August 1975 at the Savannah River Plant of the U.S. Energy Research and Development Administration in South Carolina. Two hundred feeding wood ducks were collected for study of food habits and nutrition in relation to foraging habitat use. Animal matter in the diet of females increased markedly during the breeding season and was greater (P < 0.05) than for males. Dietary protein and ash peaked during egg-laying but decreased sharply in May when nitrogen-free extract was lowest of any month and crude fiber was highest; low weights of ducks also indicated a lean period. Percent dietary protein and fat, and weights of ducks were higher during fall of 1973 when there was a good mast crop than during 1974 when a mast failure occurred. Females fed on invertebrates in shallow, open water in spring. Both sexes used deeper water areas for feeding on succulent vegetation during early summer and concentrated in Carolina bays to feed on seeds of pad plants in late summer and early fall. As fall progressed, foraging shifted to seasonally flooded stream swamps.