|Scientific Name:||Microtus pennsylvanicus|
|Species Authority:||(Ord, 1815)|
|Taxonomic Notes:||Includes M. nesophilus and M. provectus, island populations that previously were regarded as distinct species (see Modi 1986; Musser and Carleton, in Wilson and Reeder 1993, 2005). Microtus breweri from Muskeget Island, Massachusetts, sometimes has been included in this species but is here considered distinct; see Moyer et al. (1988) for recent study of relationships between these two taxa. Microtus pennsylvanicus has been proposed as conspecific with Old World M. agrestis, but chromosome differences support their recognition as distinct species (see Musser and Carleton 2005).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Linzey, A.V. & NatureServe (Hammerson, G.)|
|Reviewer/s:||Amori, G. (Small Nonvolant Mammal Red List Authority) & Chanson, J. (Global Mammal Assessment Team)|
Listed as Least Concern because it is common and widely distributed, and there are no major threats.
|Range Description:||This species occurs throughout most of Canada and Alaska (United States), south through the northern half of the United States, to Oregon, northern Utah, central New Mexico, Kansas, northern Missouri, Georgia, and South Carolina; also disjunctly (by 500 km) in Florida and in Chihuahua, Mexico (Hall 1981). Its range has expanded southward in the Great Plains since the mid-1960s as the climate has become cooler and more mesic (Frey 1992).|
Native:Canada (Alberta, British Columbia, Labrador, Manitoba, New Brunswick, Northwest Territories, Nova Scotia, Nunavut, Ontario, Prince Edward I., Québec, Saskatchewan, Yukon); Mexico; United States (Alaska, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is widespread in North America and common in many areas. In recent decades, its range has expanded southward in Kansas, Missouri, Illinois, and Kentucky (Krupa and Haskins 1996). High densities of 50-60 per acre are not unusual; average densities are probably closer to 8-10 per acre (Baker 1983).|
|Habitat and Ecology:||
It is found in a wide variety of habitats from dry pastures and wooded swamps to marshes and orchards. Needs loose organic soils for tunneling. Builds extensive underground tunnels. Nests in these tunnels under rocks or logs, and in self-constructed grassy clumps. Breeds throughout year. Peak breeding activity occurs April-October. Gestation lasts about 21 days. Litter size is 1-9 (average 4-5). Litter size is smaller in fall than in spring/summer, there may be 5-10 litters per year.
Home range seldom exceeds 0.25 acres (Banfield 1974). Successful homing of 11 of 848 voles displaced 1.2 km indicates that dispersal distance probably is more than 1 km (Ostfeld and Manson 1996). Diet consists mainly of vegetable matter, such as grasses, roots and seeds. Active day and night throughout the year.
This species can an affect old-field succession through seedling predation (Ostfeld and Canham 1993). It may inflict serious damage on apple trees by feeding on bark and vascular tissues of lower trunks and roots (Tobin and Richmond 1993). Expanding populations apparently are displacing the southern bog lemming via competitive exclusion in southeastern Kentucky (Krupa and Haskins 1996).
|Major Threat(s):||There are no major threats to this species.|
|Conservation Actions:||Its range includes several protected areas.|
|Citation:||Linzey, A.V. & NatureServe (Hammerson, G.) 2008. Microtus pennsylvanicus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 June 2013.|
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