124 



The Irish Naturalist. 



July 



than old age must have been in operation to raise the death- 

 rate. 



Would Ireland be a favourable field for such an inquiry? 1 

 think it would, because shrews are so much less abundant in 

 this country than in England that if the death-rate varies 

 locally here there must be districts where it is scarcely notice- 

 able at all. In England shrews are so common that consider- 

 able local differences might exist and escape detection. The 

 taking of a census of the dead shrews would probably be found 

 quite too laborious an undertaking. 



In Ireland the reverse is the case. The absence of the 

 Common Shrew from this country does not seem to have had 

 the effect— which might on some grounds have been expected 

 — of facilitating the multiplication of I^esser Shrews so as to 

 enable the smaller species to fill the place occupied in Great 

 Britain b}^ its larger relatives. In England Sorcx arajieiis is 

 so abundant as apparenth' to form 32 per cent, of the mam- 

 malian food of the Barn Owl ; the analysis of pellets collected 

 in man}^ parts of Cheshire — as recorded in Mr. T. A. Coward's 

 newly-published "Vertebrate Fauna of Cheshire and I^iverpool 

 Bay " — being as follows : — 



Common Shrew, . . . . .no 



Lesser Shrew, 

 Water Shrew, 

 Rat, 



House Mouse, 

 Wood Mouse, 

 Field Vole, 

 Bank Vole, 

 Water Vole, . 



3 



7 

 9 



32" 



55 

 114 



7 

 I 



From these figures it will be seen that exactly two-thirds of 

 the food (exclusive of birds) consumed b}^ the Barn Owl in 

 Cheshire is made up of two small mammals, the Common 

 Shrew and the Field Vole, which are absent from Ireland. On 

 the other hand, the four mammals in Mr. Coward's list that 

 extend to Ireland — the Lesser Shrew, House Mouse, W^ood 

 Mouse, and Rat — furnish between them only 99 specimens, 

 being all outnumbered by the Common Shrew alone; and the 

 Lesser Shrew yields only a bare i per cent, to the quota. 



