COMMON FIELD- VOLE. 325 



accomplishment which enables it in winter to feed on 

 the bark of various trees and shrubs, especially on that 

 of apple and pear trees. In winter we have occasionally 

 taken it in cellars and out-houses. An interesting account 

 of its habits as observed in Switzerland will be found in 

 M. Fatio's valuable monograph of " Les Campagnols du 

 Leman." 



The ordinary food of this species consists of all sorts of 

 roots and herbage ; in case of hunger it will eat flesh, and 

 even prey on its own species. In captivity we have 

 found it to be partial to insects, but not in such a marked 

 degree as the Red Field-Vole. 



The nest is a rounded structure of moss and leaves, 

 usually placed amongst the roots of grass in a hollow on 

 the surface of the ground. The young are four to six 

 in number, and there are three or four broods in the year, 

 so that the rate of increase of the species is very rapid. 

 This is counteracted by many opposing checks, chief 

 amongst which are the great numbers which fall victims 

 to the smaller beasts and birds of prey, notably to the 

 Weasel, the Kestrel, and the Owls, which thus prove 

 themselves the best friends of the farmer. Many, too, 

 are drowned in their burrows during floods, and on the 

 other hand a great mortality takes place in very dry 

 seasons. Occasionally they increase to a wonderful ex- 

 tent, and prove most destructive enemies to the farmer 

 and the forester. Such an abnormal multiplication took 

 place many years ago in the New and Dean Forests, 

 when great numbers of young trees were destroyed. Mr. 

 Jesse estimated that not less than two hundred thousand 

 Voles were killed in the two forests, but some of these 

 probably belonged to the next species. 



The Common Field-Vole has the head large, the muzzle 

 very blunt, and the eyes small. The ears just appear 



