What once were native grasslands in the Prairie Pothole Region of Iowa, Minnesota, North Dakota and South Dakota, are increasingly becoming corn acreage for ethanol. A study conducted for the National Wildlife Federation makes the connection between more corn plantings fueled by government incentives and mandates, and a significant decrease in grassland bird populations. University of Michigan graduate Aviva Glaser is one of the report authors and researchers. Glaser says the increases in corn plantings have affected the amount of habitat for wildlife, and what researchers have seen in the study is that it also affected bird populations. Western meadowlarks, grasshopper sparrows and upland sandpipers are among the species most affected.