Species: Microtus richardsoni
North American Water Vole
Species
Show on Lists
Encyclopedia of Puget Sound
Classification
Kingdom
Animalia
Phylum
Craniata
Class
Mammalia
Order
Rodentia
Family
Cricetidae
Genus
Microtus
NatureServe
Classification
Other Global Common Names
campagnol de Richardson
Informal Taxonomy
Animals, Vertebrates - Mammals - Rodents
Formal Taxonomy
Animalia - Craniata - Mammalia - Rodentia - Cricetidae - Microtus - , using mitochondrial DNA sequencing.
Ecology and Life History
Migration
true - false - false
Non-migrant
true
Locally Migrant
false
Food Comments
Leaves and occasionally stems of forbs are the major foods. Also eats grasses, sedges and willows. May eat some seeds and insects. Feeds on subterranean parts of plants throughout the year.
Reproduction Comments
In Alberta, mating activity was recorded late May or early June through August or September; young first entered trappable population in early July; maximum of 2 litters per year; average litter size about 5-6 (range 2-9); about 26% of young bred before their first winter (Ludwig 1988). In laboratory animals gestation lasted a minimum of 22 days.
Ecology Comments
Populations may fluctuate dramatically yearly or seasonally. In Alberta, monthly density estimates (June-September) in several streamside sites ranged from 0.2-12.2 per ha; seasonal recruitment increased population size 0.8-6.2 times, highest numbers in August or September (Ludwig 1988).
Length
26
Conservation Status
NatureServe Global Status Rank
G5
Global Status Last Reviewed
1996-11-13
Global Status Last Changed
1996-11-13
Other Status
LC - Least concern
Distribution
Conservation Status Map
<img src="http://www.natureserve.org/explorer/servlet/GetMapGif?CA.AB=S3&CA.BC=S4&US.ID=S4&US.MT=S4&US.OR=S4&US.UT=S3&US.WA=S5&US.WY=S2" alt="Conservation Status Map" style="width: 475px; height: auto;" />
Global Range
Northwestern North America. Two disjunct ranges: southwestern British Columbia south through Washington and Oregon; southeastern British Columbia and southwestern Alberta through eastern Oregon, eastern Washington, western Montana, western Wyoming, Idaho, to central Utah (Hall 1981).