House mice live within human habitations, and rarely venture outdoors where they become vulnerable to a wide range of predators. They can probably be found in or around many of the building and living areas of the reserve. The deer mouse is the most common mouse in our area. It is a small, delicate mouse with gray fur, large eyes, moderate ears, and a short, bicolored tail. It feeds on many kinds of seeds and leaves, some insects, and truffles.
Deer mice occur in many different habitats, including forests, chaparral, brush, and grasslands.
They are mainly nocturnal, but as with most other mice, they can be active at almost any time of the day or night. Watch for them during the day near areas of human activity, such as buildings, picnic grounds, parking lots, or restrooms. Trowbridge shrew Sorex trowbridgei Shrews are superficially mouse-like in appearance, but they have smaller, hidden ears and longer snouts. The Trowbridge shrew is brown in summer and gray in winter, with a bicolored tail. Shrews are insectivores, feeding on beetles, moths, heteropterans, spiders, and centipedes, supplemented with occasional earthworms or conifer seeds.