Habitat Partitioning, Body Size, and Timing of Parturition in Pygmy Shrews and Associated Soricids

Abstract

A total of 388 shrews of four species was captured during 14 months of pitfall trapping on 20 sites located in five habitat types on Land Between the Lakes, in western Kentucky and Tennessee. The soricid community was made up of one large species ( Blarina brevicauda ), one medium-sized species ( Cryptotis parva ), and two small species ( Sorex hoyi and S. longirostris ). All species showed significant differences in frequency of capture in four of the five habitats, although there was considerable interspecific overlap in habitat use. Based on estimated age and time of capture, the major period of parturition for pygmy shrews was January through early March. Individuals entered the trappable population ca. 8 weeks later. Young pygmy shrews had attained adult body size by the time they entered the trappable population. Parturition also occurred from August through December, but at a lower rate, with few individuals born in June and July. Ninety-three pygmy shrews were captured, most from March through May. No pygmy shrews were captured from June through August, a period when 30.2% of 43 southeastern shrews were captured. These two species of small shrews, which were not significantly different in size on Land Between the Lakes, may partially segregate during summer, with pygmy shrews much less active above ground.