4 FARM VERMIN, HELPFUL AND HURTFUL, 



and distinguished from the former by its blunt, short face 

 and short tail. It is at all times to be found in our pastures, 

 but attracts little notice until a favourable season and 

 abundant food stimulate its prodigious powers of multipli- 

 cation, when it breaks out in swarms and covers the land. 

 The field vole does not, like some kindred species (the 

 Thessalian vole, for instance, Arvicola Gimtherii)^ burrow 

 deeply, but scrapes out shallow runs among the heather and 

 grass roots. The first symptom of abnormal increase in the 

 voles is usually seen in what hill farmers call the ^'bog" 

 land — ix,, strong marshy land, either grazed or mown for 

 hay. Here they cut the grass betw^een the root and the 

 blade, eating the tender white part just below the ground 

 and leaving the blades in withered wasps. Having destroyed 

 that, they move to the "bent," *'lea," or dry hill pasture, 

 and thence to the heather, or to young plantations if there 

 happen to be any in their w^ay. Everywhere their presence 

 is marked by the destruction of all eatable growth, the 

 impoverishment of the stock, and increased death-rate of 

 the sheep dependent on the pasture. When the plague has 

 fairly got possession, no means are known by which it can 

 be stayed. Burning the grass and heather merely drives 

 them upon fresh ground ; it is impossible, moreover, to burn 

 all the roughness on a hill farm, as some part must be kept 

 to support the stock. Tens and hundreds of thousands ma}^ 

 be killed by men and dogs, but the voles m^ultiply faster 

 than it is possible to destroy them in this way. Birds of 

 prey — buzzards, owls, kestrels, etc. — collect in unusual 

 numbers to feast upon them ; and other species, such as 

 rooks, become predatory for the nonce, but without any 

 apparent effect upon the number of voles. 



A remarkable incident in the late plague in Scotland was 

 the presence of great quantities of the Short-eared Owl 

 {Ohts Asio)^ a migratory, day-hunting species, com- 

 monly called the woodcock owl, because it arrives and 



