“Is this a mouse or a vole?”
The photo attached to the message was a bit fuzzy, but three features stood out: a fairly short tail, small ears and eyes, and a relatively blunt face.
The answer wasn’t as simple as that, however: there are more native species of voles in Oregon than there are native species of mice.
Coos County, for example, can claim only three or four native species mice: white-footed deer mouse, Pacific jumping mouse and western jumping mouse (and jumping mice aren’t true mice), and perhaps piñon mouse in the far southeast corner of the county.
But Coos County can claim about six native species of voles. An additional seven voles can be found at least some places in Oregon that aren’t found here. Voles are placed in two closely related groups: tree voles and meadow voles.
Although they’ve been known to eat already-dead animals, voles are vegetarians, feeding on leaves, twigs, fruit, roots, bulbs and seeds. Some voles will gnaw the bark off small trees and shrubs, girdling them and perhaps killing them.
Tree voles (genera Phenacomys and Myodes) favor mature forests. White-footed voles are an uncommon vole that usually lives in riparian areas in conifer forests. Western red-backed voles burrow just under the surface of the forest floor, eating primarily the fruiting bodies of fungi — truffles, for example. In so doing, western red-backed voles spread the spores of the fungi, which are vital partners for the trees. Red tree voles live high in conifers and eat only conifer needles, meticulously stripping off the outer edges with the resin ducts. An important prey in old-growth forests, red tree voles are a substantial food for spotted owls and short-tailed weasels.
Meadow voles (here, genus Microtus) favor fields and marshes and thickets, usually cutting runway systems in the grasses and, sometimes, into the surface of the soil. Creeping (or Oregon) voles usually live in areas of coniferous forests with heavy underbrush, but here on the coast, they can also live in meadows at the edge of the forest. Long-tailed voles live in the edges between meadow and forest and in the riparian areas in forests and thickets; long-tailed voles don’t construct extensive runways. Townsend’s voles avoid the forest, living in wet meadows and marshy areas — not surprising that they are a good food source for great blue herons. (Another meadow vole, California vole, lives in a few coastal Curry County areas.)
Part of the vole/mouse confusion is due to meadow voles sometimes being called “meadow mice.” Mice, however, are in a different group of small rodents, and they tend to have longer tails (usually hairless), larger ears and larger eyes, and longer, more pointed faces. Too, mice are much more likely to enter people’s homes.
Despite the rhyming names, moles are quite different from voles. Not rodents, but in a different group of mammals, moles are carnivores with formidable broad front feet that they use for tunneling underground in search of worms, grubs, and other invertebrates. Shrews are very active relatives of moles that hunt along the surface or through or just under the litter/duff on the ground.
Of course, there are other rodents here in addition to voles and mice, including gophers, chipmunks and squirrels. Rodents in general tend to breed rapidly — helpful since they’re common and favored menu items for most of our land carnivores. Hawks and owls, herons, snakes, coyotes and foxes, bobcats and cougars, are all key consumers of rodents.
The image was a little too fuzzy to tell from appearance which of the several vole possibilities this rodent was, but as usual, the habitat played a big role in the identification. Since it was found on a concrete walkway along a human-maintained meadow (lawn) near the edge of a mature coniferous forest, I guess “creeping vole” from the range of choices.
You can arrange a personal exploration of our fascinating natural history with Wavecrest Discoveries by contacting Marty at 541-267-4027, firstname.lastname@example.org, or www.facebook.com/wavecrestdiscoveries. Questions and comments about local natural history are welcome. www.wavecrestdiscoveries.com