A study was made of the aquatic ecosystem of two national waterfowl refuges in Mississippi todeterrnine if there are significant environmental differences between the two refuges which might be correlated with evident differences in wood duck (Aix sponsa) productivity. Standing crops of seeds and plants used by waterfowl were measured. soil and water quality analyses were made, and phytoplankton concentrations were determined. Various aquatic plant communities were sampled to determine the abundance and species of macroinvertebrates. The gullet contents of 50 young wood ducks collected indicated that the sampling technique used was effective in sampling the various species present with the exception of one family, Data collected showed the aquatic ecosystem of the Yazoo Refuge located in the Delta area of Mississippi was more fertile and supported larger standing crops of plants and animals than the Noxubee Refuge located largely in the Interior Flatwood Soils area of Mississippi.
