ACORN SELECTION BY FEMALE WOOD DUCKS

Acorns of southern bottomland red oaks (Quercus spp.) are important wi nter foods of wood ducks (Aix sponsa). Therefore, we tested if captive , wild-strain female wood ducks would exhibit preferences among differ ent species of common bottomland red oak acorns, including willow oak (Q. phellos), water oak (Q. nigra), cherrybark oak (Q. falcata var. pa godaefolia), and Nuttall oak (Q. nuttallii) during winter 1991-92. Wil low oak acorns were selected over all other equally available acorns, whether presented in mixed- or single-species feeding trials. Willow o ak acorns had smalles top width, thinnest shell, and greatest meat: sh ell mass ratio, which perhaps facilitated ingestion and nutrient assim ilation by wood ducks. Future research should clarify mechanisms for a corn selection by wood ducks and mallards (Anas platyrhynchos) in capt ive and natural environments. Managers might use willow oak and other appropriate tree species (i.e., considering geographical, hydrological , and soil conditions) in restoration of lowland hardwood forests.