Reproduction of wood ducks in large and small nest boxes

wood dude (Aix sponsa) production may decrease because of excessive egg accumulation from dump nesting in natural cavities and nest boxes. We evaluated a management strategy of reducing nest box size as a means to reduce excessive egg accumulation at Noxubee and Yazoo National Wildlife Refuges, Mississippi, in 1994 and 1995. We compared duck use of nest boxes, nest success, number of hatched and unhatched eggs, an index of dump nesting, duckling production, and cost-benefits between large, conventional boxes and small, experimental structures (approx 1/2 size), both constructed of wood. Large boxes were used more frequently by nesting ducks and contained more eggs. More ducklings exited the large boxes, and dump nests occurred more often in large than small boxes (P less than or equal to 0.05). Nest success was similar between box types (P > 0.05). However, small nest boxes were more cost-effective than large boxes because they cost less to construct. Small boxes offer managers an economical structure that is easy to install, and suitable for producing wood ducks and hooded mergansers (Lophodytes cucullatus).