Common name: California Vole
Scientific name: Microtus
Habitat: common in grasslands, wetlands and wet meadows
Size: up to 14 cm long excluding tail
Description: The California Vole is covered with grayish-brown fur. Its ears and legs are short and it has pale feet. It has a cylindrical shape (like a toilet paper roll) with a tail that is 1/3 the length of the body.
Fun facts: California Voles make paths through the grasslands leading to the mouths of their underground burrows. These surface “runways” are worn into the grass by daily travel. When chased by a predator, a vole can make a fast dash for the safety of its underground burrow using these cleared runways. If you walk quickly across the grassland you will often surprise a California Vole and see it scurry to its burrow.
Life cycle: California Voles reach maturity in one month. Female voles have litters of four to eight young. In areas with abundant food and mild weather, each female can have up to five litters in a year.
Ecology: The California Vole can dig its own underground burrow system but it often begins by using Pocket Gopher burrows. The tunnels are usually 1 to 5 meters long and up to one half meter below ground, with a nesting den somewhere inside. The ends of the burrows are left open. Many insects, spiders, centipedes, and other animals live in their burrows. Thus, the California Vole creates habitat for other species and the Pocket Gopher improves habitat for the vole.
The California Vole is mainly an herbivore. It eats grasses and other green plants and their seeds. It will sometimes eat bird eggs or other protein-rich food it can find easily. Voles are a major food source for hawks, owls, egrets, snakes, and coyotes. Weasels hunt voles by scurrying right into the vole’s burrow system. Weasels even live in the Vole’s den chamber, after eating the resident vole!
Conservation: The California Vole can live in grasslands and fields that are not ploughed every year, such as alfalfa and vineyards. It likes to visit sugar beets and vegetables that are large enough to provide cover from its predators. However the California Vole can cause damage to crops, so farmers sometimes poison them.
Investigate: Vole burrow openings are often worn bare and littered with fecal droppings. You can sometimes find grass parts or flowers lying inside or near the burrow entrance. (Voles are sloppy eaters!) When a California Vole eats seeds on its “front porch”, it often leaves the inedible husks of the seeds in a pile by the door. Such piles are called “middens”. Look for midden piles in the grassland and see if you can tell what plant(s) the seeds came from. This will help you to find out more about the vole’s place in the food web.