THE COMMON SHREW 105 



mammals and by birds, but by a very general and mysterious 

 mortality. This is most commonly observed in the autumn, 

 but prevails also in summer and even in spring. Its cause does 

 not appear to be thoroughly understood. So many shrews 

 may be found lying dead on footways, or other bare ground 

 near their haunts, as to have led to the belief mentioned above 

 among country people, that one cannot cross a public way 

 without incurring instant death. This mortality, as Tomes ^ 

 was able to satisfy himself, extends to individuals of both 

 sexes and of all ages. It is naturally more perceptible on 

 roads or bare places, but if, as has been suggested, it is no 

 less severe in woods and tall herbage, where it is necessarily 

 impossible to appreciate its extent, then its magnitude must 

 indeed be enormous. It is also associated with the two other 

 British species, the Pygmy and Water Shrews, and must, there- 

 fore, be due to causes which affect all three alike. 



Several plausible explanations have been put forward 

 to account for this mortality. It has been attributed to 

 sexual excitement ^ leading to wandering recklessness, and 

 consequent capture by predatory animals,' but, if that be so, it 

 is difficult to understand why marks of violence upon the 

 carcases are comparatively rare, and further, why they are 

 left uneaten, since, as already shown, shrews are not always 

 refused by beasts and birds of prey.* MacGillivray connected 

 it with drought,^ resulting in scarcity of food, a suggestion only 

 tenable had we evidence that the autumnal mortality is greater 

 in countries of dry than in those of moist climate. 



The late Robert Service, after examining some hundreds 

 of wayside shrew carcases,* wrote me that he had formed the 

 belief that, in the neighbourhood of Dumfries at least, the 

 Hedgehog is the principal cause of shrew mortality. But that 

 this cannot be so is shown by the fact that Mr Millais observed 

 Lesser Shrews lying dead on a worn trail in North Uist, as I 



' In Bell, ed. 2. 2 j_ l_ Y^riz.-^'p, Journal of a Naturalist, ed. 2, 1829, 145. 



' Jonathan Couch, Illustrations of Instinct, 1847, 279. 



* They are killed by cats, and occasionally by dogs, but rejected by most beasts of 

 prey. They are devoured by a few birds of prey, especially by Common and Rough- 

 legged Buzzards, and by most of the owls, but not in numbers (CoUett). 



' From this Adams believes that small rodents escape by migration. 



« See article on Hedgehog, p. 67. 



H 



