Continued Westward Expansion of Woodchucks (Marmota monax) in Nebraska

During the last century, the distribution of the woodchuck (Marmota monax) has expanded westward in parts of the Great Plains. Expansive grasslands of the Great Plains were formerly a barrier to forest-dwelling species, but changes since European settlement have enabled some woodland species to colonize the region. By 2000, woodchucks generally reached across the central portion of Nebraska. We compiled new county records and estimated the continued westward expansion rate of this large, diurnal squirrel in Nebraska. We documented new records of M. monax along much of the former western distributional limits in central and southern parts of the state, including a large westward movement along the Platte River into central Keith County. Westward movements appear to follow wooded rivers and their tributaries throughout the state. We estimated that in the last 18 years, M. monax expanded westward along the Platte River from central to western Nebraska at a rate of 9-13 km/year. If not already present in northeastern Colorado, M. monax could reach the Colorado border in <5 years. We acquired many records of M. monax reported as nuisance/damage control to the Nebraska Game and Parks Commission. We suspect that as this species continues to advance westward in the state and other areas of the Great Plains, more residents will report this species as a nuisance. Although a novel species in much of this grassland region, M. monax will provide habitat for a number of other species with its elaborately constructed burrows.