Harvested areas had higher percentages of bare ground and lower levels of standing residual than unharvested areas. The litter layer was thinner and the standing residual was shorter in the harvested area. These areas also had a higher percentage of legumes and non-grass herbaceous plants than unharvested areas. The research showed that several species of birds, such as the American goldfinch, ring-necked pheasant, and song sparrow, tolerate both harvested and unharvested switchgrass areas. Unharvested areas were inhabited by birds like the dickcissel, Henslow s sparrow, and sedge wren that prefer tall, dense vegetation.
Birds preferring harvested areas include the bobolink, and Eastern and Western meadowlark.
The researchers found that harvesting switchgrass in August created habitat the following year favoring six declining grassland bird species. These birds require short, structurally diverse vegetation. Overall, there were more pairs of grassland birds in harvested than in unharvested parts of the fields. Providing a balance between harvested and unharvested areas creates habitat for the greatest number of declining grassland bird species. Switchgrass could offer an environmentally sound crop on highly erodible land if energy economics change.