The largest number of grassland species are found in the northern Great Plains, especially in the Dakotas, Montana, and adjacent Canadian provinces. The fewest species are found from the Rocky Mountains westward and in most of eastern North America.
Declines prevail throughout North America.
Areas with increasing trends are generally small and localized. Factors responsible for this decline include the destruction of suitable habitats as well as increased mowing of remaining grasslands for hay production. Literature Cited Johnson, D.H., and M.D. Schwartz. 1993. The Conservation Reserve Program and grassland birds. Reynolds, R.E., T.L. Shaffer, J.R. Sauer, and B.G. Peterjohn.