The Food of the Common Shrew Sorex araneus L. (Insectivora: Soricidae) in Britain

Abstract

Mainland Britain has three species of shrew; Sorex araneus L. the common shrew, S. minutus L. the pigmy shrew and Neomysfodiens (Pennant) the water shrew. This paper concerns the common shrew only, a species whose almost unceasing activity and voracity have attracted the attention of natural historians from the ancients to the present day. Crowcroft (1957) summarizes present information on the biology of the common shrew. Further information on ecology may be found in Shillito (1960) and on metabolism in Hawkins & Jewell (1962). Notable in these works is the almost total lack of information on the feeding of wild shrews. The common shrew spends much of its life tunnelling through the loose accumulation of plant detritus in woods, hedgerows and rank grassland. From this material it must each day glean a mass of food in the form of invertebrates equal to its own body weight (about 8-0 g) (Rorig 1905; Adams 1912; Tupikova 1949; Crowcroft 1957; Hawkins & Jewell 1962). Present qualitative information on the diet of British shrews comes mainly from experiments in which captive animals have been fed as wide a range of prey as was available (English 1908; Adams 1912; Cranbrook 1959 (on Neomysfodiens)). Greater meaning was given to these species lists by the more sophisticated foraging trials of Shillito (1960) and the preference experiments of Crowcroft (1957). The more direct method, of gut analysis, has been advocated (Hamilton 1930; Crowcroft 1963) but so far it has been used in Britain only for a small sample (n = 4) of Sorex minutus (Newstead 1947). In the present study, analysis of the gut contents of 444 wild-trapped comm;on shrews is described. These analyses are preceded by an account of laboratory feeding trials whose object was to aid the interpretation of the analysis results.