By Mike Watson
Geographic Range
Pacific coast of northern California and Oregon.
Habitat
(6232 ft)
Myodes californicus prefers forested riparian habitats and is often found at stream edges. Abundance is positively correlated to size of logs, depth of organic soil, diameter of standing trees and snag size. Overall, old-growth, naturally degenerate forests with moist soils, abundant ground cover and litter are the ideal habitat.
These animals are found in the following types of habitat:
temperate 
.
Terrestrial Biomes:
forest .
Other:
riparian .
Physical Description
(0.53 to 1.41 oz; avg. 0.97 oz)
(4.33 to 7.48 in; avg. 5.91 in)
Dorsally, this species is chestnut brown, mixed with black. Its color gradually lightens on sides to buff-gray on belly. It has an indistinct reddish stripe along back. The tail is bicolored and roughly 1/2 the length of the head and body.
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
February to November
Myodes californicus construct lichen nests under logs and forest floor debris. Mating occurs from February to October and young are born from April to November (Alexander, 1999).
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
Behavior
Although they are sometimes active during the day, M. californicus are primarily nocturnal. They are active year round (do not hibernate). They spend most of their time moving amongst forest floor litter and underground in search of sporocarps. They are often found around and under downed trees, and appear to use log overhangs as travel corridors.
Food Habits
Interestingly, M. californicus seems to rely heavily on fungal sprorocarps (75 to 90% of diet). These voles appear to have physiological and morphological adaptations of their digestive sytems which allow them to digest to fibrous materials of EMF (ectomycorrhizal fungi) sporocarps more efficiently than their body size would suggest. Myodes californicus is also known to eat some lichens, green vegetation (late winter), seeds, twigs, and insects (and occasionally insect larvae). Foraging is mostly terrestrial, but they occassionally climb into trees and shrubs in search of food. There is some evidence that they cache fungi for later consumption.
Primary Diet:
mycophage .
Animal Foods:
insects.
Plant Foods:
leaves; seeds, grains, and nuts; lichens.
Foraging Behaviors:
stores or caches food .
Predation
- American martens (Martes americana)
- long-tailed weasels (Mustela frenata)
- ermine (Mustela erminea)
- striped skunks (Mephitis mephitis)
- eastern spotted skunks (Spilogale putorius)
- spotted owls (Strix occidentalis)
- other raptors (Falconiformes)
Myodes californicus are an important prey base for the forest ecosystem. They are preyed upon by martens, weasels, skunks, owls (including Spotted Owls), and other carnivorous birds and mammals.
Economic Importance for Humans: Positive
M. californicus feed primarily on the ectomycorrhizal fungi symbionts of trees and probably help disperse the fungal spores. These symbiotic relationships are believed to be essential for the health and growth of trees
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
Myodes californicus are adversely affected by habitat fragmentation (due to reduced sporocarp abundance in cleared fields). They are also known to avoid road verge habitats, prefering to remain towards the forest interior. Human development of land, therefore, can apply a significant and damaging effect on M. californicus abundance.
For More Information
Find Myodes californicus information at
Contributors
Mike Watson (author), University of Michigan.
Bret Weinstein (editor), University of Michigan.
