Multi-year studies in wildlife science and management can provide novel insights not detected in short-term investigations. Therefore, we continued a 2-year study by Stephens et al. (1998) to evaluate wood duck (Aix sponsa) reproduction in conventional and small nest boxes (i.e., approximately one-half conventional size) at Noxubee and Yazoo National Wildlife Refuges (NWRs) in Mississippi. Small nest boxes were designed to deter excessive dump nesting by wood ducks at these refuges. During 1994-1997, use of large boxes by wood ducks remained high (≥70%) at both study areas, but use of small boxes declined from 61% in 1994 to 34% in 1997 at Noxubee NWR. Concomitantly, use of small boxes by passerine birds increased from 14% to 65% at Noxubee NWR, but use of large boxes by passerines never exceeded 15%. Large boxes never were used by passerines at Yazoo NWR. Large boxes contained more duck eggs and dump nests than small boxes, but wood duck nest success did not differ between the 2 box types. More ducklings departed large boxes, but cost per duckling was less from small than large boxes because of the lesser cost of constructing small boxes. Large and small boxes provide managers with choices for producing wood ducks and other birds relative to their objectives and financial resources.