Studies conducted 1961-65 at the Montezuma National Wildlife Refuge in New York demonstrated that mallards (Anas platyrhynchos) and black ducks (Anas rubripes) make extensive use of stumps and dead snags for nest sites. Nest densities in timbered habitats compared favorably with those in untimbered habitats. Nest success was generally higher in timbered than in untimbered areas, except for a newly flooded impoundment where nest success was poor. A simple artificial nest structure was used to increase the number of available nest sites in some of the timbered habitats. Development of stump-nesting populations of ducks may furnish a means of increasing waterfowl production in forested areas.