We studied availability of natural cavities for wood ducks (Aix sponsa) on 5 areas in 3 southeastern states in 1988-1990 because of U.S. Fish and Wildlife Service (USFWS) guidelines that called for the reduction of nest boxes on National Wildlife Refuges. Selected forested wetlands dominated by bald cypress (Taxodium distichum) or tupelo gum {Nyssa aquatica) were randomly sampled using 0.5-ha plots to estimate the density of cavities suitable for wood duck nesting. Density of suitable natural cavities in live, mature (≥28 cm dbh, ˉx age = 117.6 years) bald cypress-tupelo gum stands averaged 0.08/ha (SE = 0.03) and ranged from 0.00 to 0.29/ha. Bucket cavities were deemed unsuitable because of their tendency to retain moisture in dry periods. The mean cavity density for all areas in this study was among the lowest densities reported for timber stands in North America. The low cavity densities in these bald cypress-tupelo gum areas, and other bottomland hardwood stands in the Southeast suggest that nesting boxes may be needed if wood duck production is a management goal.
