io8 SORICID^— SOREX 



still unpublished, observations by Mr Adams, all of which he 

 has most kindly placed at my disposal. Amongst forty-eight 

 Pygmy and three hundred and ten Common Shrews captured 

 after December, there was not a single adult of either sex, and 

 not a single female that had already bred. Consequently, 

 according to Mr Adams, the autumnal "epidemic" is due 

 to nothing more than old age ; old age in the case of the 

 Common and Lesser Shrew being reached in, roughly, thirteen 

 or fourteen months.^ 



To show that the proportions of adults and juveniles 

 actually vary definitely according to season, Mr Adams has 

 prepared a table showing, the average size of shrews throughout 

 the year. This has been summarised above on page 92, and 

 bears out his conclusions in a very remarkable manner. 



On the whole, it seems that there is probably more than 

 one cause of mortality. It is not restricted to any one of our 

 three British species. It may be, however, connected with the 

 breeding season, and occasionally, at least, with some bad- 

 tempered but not hungry assailant. Add to the above the 

 known pugnacity and fragility of all three species, so well 

 illustrated by the late John Cordeaux's observation of two male 

 Water Shrews which fell in mortal combat and yet showed 

 hardly a trace of their encounter,^ and we have a handful of 

 causes, any one of which — and there may be many others 

 — might answer for many deaths, and that specially in 

 summer when the countryside is crowded with young shrews 

 all newly launched upon a thickly-populated world, and ready 

 victims in the struggle for existence amidst the changing 

 conditions of food supply and atmosphere. 



A remarkable feature of the natural history of the present 

 species is its, at least occasional, habit of congregating in 

 numbers on one small area. Thus, Mr W. N. McCartney, 

 more than thirty years ago, recorded* his observation in May 

 of " between one hundred and one hundred and fifty shrew mice 

 running nimbly about, uttering their peculiar sharp cry . . . 



' See "A Hypothesis as to the cause of the Autumnal Epidemic of the 

 Common and the Lesser Shrew, with some Notes on their Habits," in Mem. 

 and Proc. Manchester Lit. and Philosoph. Soc, liv., lo, 1-13 and plate, read 8th 

 February 1910 ; also comments by C. B. Moffat, Irish Naturalist, 1910, 121-126. 



^ See below under Water Shrew. ^ Zoologist, 1861, 7624. 



