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This paper describes changes in important demographic parameters of a grassland (non-orchard) population of the meadow vole (M. pennsylvanicus) studied since November 1974 near Charlottesville in piedmont Virginia. (This study was supported by the Dept of Biology of the University of Virginia until August 1976, and is now the joint project with Ray D. Dueser, Dept of Environmental Sciences, UVA, and is supported by our respective departments.) Methods used are similar to those of C.J. Krebs, and require weekly live-trapping during which each vole is weighed and assessed for reproductive state and new voles are tagged. Such information has been summarized using Krebs' demographic programs and gives population information on density (minimum number known to be alive), growth and survival rates for each sex, plus movement and other data. The patterns reported here are those of the two control grids, and are repeated in principle on four experimental grids on the same (Birdwood) research tract.