I.J. Ball L.M. Cowardin John E. Mathisen John H. Riechmann D.S. Gilmer 1978 <p>Radio telemetry was used to locate 31 wood duck (<i>Aix sponsa</i>) nest cavity sites in 16 forest stands. Stands were of 2 types: (1) mature (mean = 107 years) northern hardwoods (10 nest sites), and (2) mature (mean = 68 years) quaking aspen (<i>Populus tremuloides</i>) (21 nest sites). Aspen was the most important cavity-producing tree used by wood ducks and accounted for 57 percent of 28 cavities inspected. In stands used by wood ducks, the average density of suitable cavities was about 4 per hectare. Trees containing nests were closer to water areas (P &lt; 0.05) and the nearest forest canopy openings (P &lt; 0.01) than was a random sample of trees from the same stands. A significant (P &lt; 0.005) relationship existed between the orientation of the cavity entrance and the nearest canopy opening. Potential wood duck cavities usually were clustered within a stand rather than randomly distributed. Selection of trees by woodpeckers for nest hole construction probably influenced the availability of cavities used by wood ducks. A plan for managing forests to benefit wood ducks and other wildlife dependent on old-growth timber is discussed.</p> application/pdf 10.2307/3800266 en Wiley Natural cavities used by wood ducks in north-central Minnesota article