Wood Duck Nest Sites in Bottomland Hardwood Forests of Mississippi

Abstract

We studied the occurrence of natural cavities suitable for wood duck (Aix sponsa) nest sites in mature bottomland hardwood forests on Noxubee National Wildlife Refuge (NNWR) and Delta National Forest (DNF), Mississippi in 1985 and 1986. We found 0.19 ? 0.09 (SE) and 0.23 ? 0.13 suitable cavities/ ha on NNWR and DNF, respectively. Sycamore (Platanus occidentalis) and beech (Fagus grandifolia) trees contained 60% of the suitable cavities on NNWR, but composed only 2.6% of the available trees. Cavity rates on the 2 areas were among the lowest reported for mature forests in North America. The paucity of suitable cavities suggests nest box programs are more important to maintain breeding populations of wood ducks in riparian bottomland forests of the lower Mississippi Valley and the Gulf Coastal Plain than has recently been reported along the northern edge of their range. J. WILDL. MANAGE. 53(2):378-382 The lack of natural nest sites is a factor limiting nesting wood duck populations (Hawkins and Bellrose 1940, McLaughlin and Grice 1952, Haartman 1957, McGilvery 1968). However, guidelines for nest box programs vary among regions of the U.S. Fish and Wildlife Service (USFWS); personnel in some regions have suggested that artificial nesting structures be used for research, demonstration, and other special purposes rather than as a principal means of achieving production goals (USFWS 1982). Under these guidelines and cost constraints, some USFWS refuge managers were gradually phasing out wood duck nest box programs (J. L. Tisdale, NNWR, pers. commun.). The value of nest box programs for wood ducks in Wisconsin has been questioned on the basis that an overwhelming preponderance of production occurred in natural cavities (Soulliere 1986) that were estimated to far exceed needs of the nesting population (Soulliere 1988). Studies of wood duck nest sites on 16 areas (Lowney 1987) from Canada (Prince 1968) to Mississippi (Woods 1964) have reported from 5.44 to 0.08 nest sites/ha, respectively. Studies of cavity occurrence in bottomlands in the central and southeastern United States suggest that the occurrence of suitable cavities for wood duck nest sites is often <1/ha. However, estimates from southern areas were limited by data that were collected from small areas (Woods 1964, Teels 1975), cutover stands (Weier 1966), altered stands (Strange et al. 1971), or combinations of these. Information on natural cavity occurrence by stand type and tree species characteristic of the southeastern United States is needed. We report on the occurrence rates of natural cavities in mature bottomland hardwood forests of the Gulf Coastal Plain and the lower Mississippi River Valley floodplain. We thank K. M. Blanton, D. T. Reinke, R. E. Herring, and P. A. Morrison for field assistance. G. A. Hurst, R. M. Kaminski, and R. J. Muncy review d the manuscript. Funding was provided by Mississippi Cooperative Fish and Wildlife Research Unit and Mrs. C. B. Bradley. The Mississippi Department of Wildlife Conservation, Wildl fe Management Institute, Mississippi State University, USFWS, NNWR cooperate with the Mississippi Cooperative Fish and Wildlife Research Unit.