The number of breeding marsh birds per restored wetland ranged from 1-18 species during 1989 and 1990 in northern Iowa. There was a positive significant relationship between species richness and wetland area. Birds rapidly colonized restored wetlands, usually within the first year of restoration. How long a wetland has been drained does not affect bird species richness but did affect the development of marsh vegetation. Relative coverage of emergents, floating plants, open water, and bare ground affected bird species richness. Restoration efforts should concentrate on large wetland basins that have been recently drained or have a tendency to reflood frequently.