The Short-Tailed Shrew and Field Mouse Predation

The ecological relationship between short-tailed shrews (Blarina brevicauda) and mice (chiefly Microtus pennsylvanicus) has long been a matter of conjecture and study. As early as 1842, Plummer (1844) fed live mice to a captive shrew and described destruction of mouse by shrew. Morden (1883), Merriam (1886), Shull (1907), Babcock (1914), and Hamilton (1930) have published reports of a repetition of this early experiment. Merriam (op. cit.) concluded from such evidence that the Short-tailed Shrew preys largely upon mice, and is, consequently, of great economic value to farmer .. . Shull (op. cit.), using similar evidence plus significant fact of finding a Blarina nest composed exclusively of hair of voles with three carcasses and legs and tails of twenty others nearby, came to conclusion that this shrew preys heavily on mice. Hahn (1908) and Bailey (1923) present evidence of actual pursuit and capture of voles by Blarina under natural conditions. Hamilton (1930 and 1941) made detailed studies of food of short-tailed shrew by analyzing contents of a total of 460 stomachs. He found mouse remains in only 14 stomachs (3 percent) and concluded from this direct evidence that the short-tailed shrew has been credited with greater mouse destruction than it is capable of committing. The recent discovery by Pearson (1942) of a poisonous material in saliva from submaxillary glands of Blarina suggests that this shrew may have greater potentialities as a mouse destroyer than has been recognized in recent years. Further evidence was sought on this shrew-mouse relationship during late winter and early spring of 1943 at Ithaca, New York. This resulted in discovery of several winter nests, their associated burrows, over 200 well preserved scats along with other less well preserved droppings, and various mouse remains in vicinity of nests.