322 THE ZOOLOGIST. 



their runways through the meadows and grain-fields result in 

 the loss of at least one-fifth of the crop. 



Again, the depredations of Ground Squirrels and Gophers 

 in the prairie regions of the Mississippi Valley, and in the far 

 west, are well known, and yet the extent of the damage they do 

 is not generally recognised. In a fertile part of the Sacramento 

 Valley, in California, a few years ago, the sudden increase in a 

 species of Ground Squirrel which fed upon grain caused the 

 land to depreciate one -half in value ; or, to he more explicit, 

 land which previously fetched one hundred dollars an acre could 

 not he sold for fifty ; and this depreciation was due solely to the 

 abundance and ravages of the Squirrels. 



Here, in England, it is on record that different parts of the 

 country have, at various times, been overrun with a plague of 

 Field Mice, which has caused incalculable damage to trees and 

 crops, and has been only partially checked by devices for 

 trapping them, and by the attacks of birds of prey, especially 

 the Short-eared Owl, Asio accijntrinus. Thus Jesse, in his 

 ' Gleanings in Natural History,' describes how the trees in the 

 Forest of Dean, in Gloucestershire, were seriously damaged by 

 Field Mice, great numbers of which were taken in pitfalls of a 

 peculiar construction. Childrey, in his 'Britannia Baconica,' 

 1660 (p. 14), mentions a similar swarm of mice which appeared 

 in Denge Hundred, Essex, in 1580, and eat up all the roots of the 

 grass. " A great number -of Owles," he says, "of strange and 

 various colours assembled and devoured them all, and after they 

 had made an end of their prey, they took flight back again from 

 whence they came." From this we may infer that this plague 

 occurred in the autumn, when the Short-eared Owls arriving 

 from Norway and Sweden to spend the winter here, fared 

 sumptuously upon the mice until the time came for them to 

 leave us in the following spring. 



A similar account from Market Downham, in Suffolk, is 

 given in the 'London Magazine' for 1754, where we are told 

 that "the parishioners pay almost the same veneration to the 

 Norway Owls as the Egyptians did to the Sacred Ibis, and will 

 not at any rate annoy them, on account of their destroying the 

 Field Mice, with which they are infested commonly about once 

 in six or seven years." 



But of all plagues of this kind in modern times, none 



