As a consequence of extensive habitat loss and fragmentation, grassland bird populations have declined substantially across much of North America. To assess management strategies for restoring and maintaining suitable habitat for grassland birds, we conducted a four-year survey of grassland-breeding passerines in the restored tallgrass prairies of the Carleton College Cowling Arboretum in Northfield, Minnesota. Between 2010 and 2013, we sampled bird populations weekly during the breeding season in ten adjacent management units that differed in size and spatial configuration. We used principal components analysis (PCA) to compare avian community composition among the units and to examine the association between habitat properties and makeup of the community. The size of a management unit had no effect on the bird community, but there was a strong impact of forest edge on community composition. Management units with less exposure to forest edge had greater abundance of grassland-obligate but not grassland-facultative birds. Management units that were less exposed to forest edge also had greater overall grassland bird diversity. These findings highlight the importance of maintaining grassland patches far from forest edges to increase habitat suitability for a diverse assemblage of grassland avifauna.