POPULATION DYNAMICS AND ACTIVITY OF SOUTHERN SHORT-TAILED SHREWS (BLARINA CAROLINENSIS) IN SOUTHERN ILLINOIS.

We captured, marked, and recaptured southern short-tailed shrews (Blarina carolinensis) during a 30-month livetrapping study in a woodlot in Jackson County, Illinois, to compare aspects of their life history with those of the northern short-tailed shrew (B. brevicauda). A total of 106,496 trap checks (15,782 trap nights) resulted in 3,430 captures of 313 B. carolinensis from February 1996 through August 1998. Trapping mortality was only 18 individuals. Sex ratio did not differ from 1:1. Estimated population density peaked at 57 individuals/ha in late summer and autumn then declined during winter. Recruitment, including birth and immigration, peaked in spring and late summer each year. Individuals entering the population in the spring and early summer had higher survival rates than those entering in the autumn. A weak correlation was found between recruitment and precipitation, and between population density and humidity. Shrew activity (timing of captures) showed significant relationships with light condition and season. During summer, shrews were caught more frequently at night. In the winter, they were captured more frequently during the day. Capture rate was negatively related to precipitation and positively related to humidity. Population dynamics and activity patterns were similar to those of B. brevicauda. [ABSTRACT FROM AUTHOR]