Species-Specific Management (SSM)

Shrews

There are eight notable species of shrews in the southern Appalachian Region. Shrews are profoundly beneficial in improving forest soil. Burrowing through logs for nest sites and insects hastens breakdown into nutrients, and soil burrowing directly aerates the soil and introduces organic matter and water. Very likely they play an important role in distributing mycorhizzae spores, thus building a mature water and nutrient supply for roots.Their habitats consist of moist fields, woodlands, and small pools of water. Shrews have a life span between 1 and 2 years althought the majority of them do not live beyond a year.

The short-tailed shrew (Blarina brevicauda) is very abundant within the southern Appalachian forests. They, like the white-footed mouse, form a major food source of the mamamalian, reptilian, and avian carnivores of the forest.

All species, except water shrews, require similar resources and living space. Here are ways to improve forest lands for shrews.

1. The best areas are moist but well drained. The best areas should have a good morning dew, but avoid bogginess or flooding.
2. Abundant beetle larvae (grubs),earthworms, and other insects become the quest of the manager.
3. Food supply is critical. Shrews will die if they cannot feed every 2 to 3 hours. Suckling females eat 125% of their body weight in food each day.
4. Control free-roaming cats and dogs.
5. Shrews are particularly vulnerable to toxins like insecticides and heavy metals. Water shrews are especially vulnerable to water pollution.
6. Stop pesticide spraying in habitats inhabited by shrews. This will provide an increase in the number of insects and larvae available for consumption.
7. Prevent forest fires. Fires destroy ground vegetation, insects that live among and on roots, and valuable food.
8. Gestation period is 21-22 days. Young grow to adult size in 4-6 weeks and are sexually mature at about 3 months. Thus the reproductive potential of the population is great.
9. The first week for a young litter is critical. There must be abundant food and a good nest. Prevent timber cutting that disturbs nesting in late spring/early summer. Good nest areas can be provided by placing branches pruned from trees in clumps, and by adding nest boxes.
10. A deep leaf litter layer should be maintained. A mulch bed is an excellent source of insects for food. Adding a manure pile for earthworms and other creatures is also recommended.
11. Shrews have a toxic bite, and will attack and eat small rabbits and birds if other foods are not abundant enough. It is said that they may climb trees to raid bird nests (?).
12. Other prey includes snakes, mice, and voles. Prey found at streams include small fish, spiders, beetles, and salamanders, slugs, and snails.
13. Preferred areas vary by species, but include grassland, woody areas, wood edges, marsh edges, brushy areas, old stone walls, and deserted building rubble.
14. Shrews participate in regulating insect populations. Shrew predation can reduce sawfly larvae and defoliating caterpillars by 65%, in some cases 88%, potentially saving valuable timber stands and forests.
15. During hunting and/or trapping seasons, concentrate on foxes, coyotes, and raccoons. By reducing these numbers, there is a great chance that the shrew population will increase.
16. They may be parasitized but they do not directly spread disease, carrying instead disease-spreading ticks and fleas.
17. Direct contact can be avoided; a shrew will usually flee if disturbed.
18. Shrews do not migrate except to another field or woodlot close by.
19. Observe population index changes and adjust activities and investments to assure rational resource management and development.
20. Keep good public relations. Notify the public of your intentions and educate them on the importance of high shrew abundance.

A contribution of Kim Guenther and Karl Knipling (1992), Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0321

This Web site is maintained by R. H. Giles, Jr.
Last revision January 17, 2000.