Shrews have been known to enter buildings. Rodent-proofing will also exclude shrews from entering structures. Look along the foundation sill, pipes, eaves, attic screens and other places where gaps occur in the structure. Shrews have been found in attics so don't forget to look along eaves. Place hardware cloth of 1/4-inch (0.6-cm) mesh over potential entrances to exclude shrews. The pygmy shrew (Sorex hoyi) may require a smaller mesh (but this would be very uncommon). Coarse steel wool placed in small openings can also exclude shrews. Steel wool will rust; copper wool or netting will last longer. Foam products are easily chewed by small mammals, but may also be effective. Exterior grade caulk can also be an excellent, more permanent choice. Keeping vegetation and other potential hiding cover away from the foundation is helpful in reducing the attractiveness of this area as habitat. Small mammals tend to be very concerned about avoiding predation, for good reason.
Resources: (online)
Shrew Control
Rodent Proofing Techniques
