Most species of shrews do not have significant negative impacts and are not abundant enough to be considered pests. Shrews sometimes conflict with humans, however. The vagrant shrew (Sorex vagrans) has been reported to consume the seeds of Douglas fir (Pseudotsuga menziesii), although the seeds constitute a minor part of the diet. The masked shrew (Sorex cinereus) destroyed from 0.3% to 10.5% of white spruce (Picea glauca) seeds marked over a six-year period. Lodgepole pine (Pinus contorta) seeds are also eaten by the masked shrew. Radvanyi has published pictures of shrew, mouse (Peromyscus, Microtus, and Clethrionomys spp.), and chipmunk (Eutamias spp.) damage to lodgepole pine seeds and describes shrew damage to white spruce seeds.
The northern water shrew (Sorex palustris) may cause local damage by consuming eggs or small fish at hatcheries. The least shrew (Cryptotis parva), also known as the bee shrew, sometimes enters hives and destroys the young brood. The northern short-tailed shrew (Blarina brevicauda) has been reported to damage ginseng (Panax spp.) roots. Short-tailed and masked shrews reportedly can climb trees where they can feed on eggs or young birds in a nest or consume suet in bird feeders.
The pugnacious nature of shrews sometimes makes them a nuisance when they live in or near dwellings. Shrews occasionally fall into window wells, attack pets, attack birds or chipmunks at feeders, feed on stored foods, contaminate stored foods with feces and urine, and bite humans when improperly handled. Potential exists for the transmission of diseases and parasites, but this is poorly documented.
The house shrew (Suncus murinus) is an introduced species to Guam. It has been reported as a host for the rat flea (Xenopsylla cheopis) which can carry the plague bacillus (Yersinia pestis). Compared to rat (Rattus spp.) numbers, however, house shrew numbers are usually low, and risk of plague transmission is probably minimal. The house shrew is accustomed to living around humans and houses, which increases its damage potential. It is considered smelly and noisy, making incessant, shrill, clattering sounds as it goes along. On occasion, it destroys stored grain products.
Resources: (online)
Shrews
