130 THE ZOOLOGIST. 



Destructive visitations of voles took place in 1825, in the oak- 

 coppices of Cameron, Dumbartonshire; and in 1864 — 67 in the 

 woods of Drumlanrig, Dumfriesshire, when the oak, holly, and 

 ash suffered severely, but the fir and mountain ash were spared. 

 On the other hand, in 1863-64, on the estate of Rannoch, Perth- 

 shire, Sir Robert Menzies stated that his woods suffered severely, 

 but that the Scots firs only were attacked. 



Finally, there was the serious outbreak on the hill-pastures of 

 Roxburghshire and small portions of Dumfriesshire in 1875-76, 

 by which much of the land suffering under the present visitation 

 was overrun. This is fully described in Sir Walter Elliot's paper 

 above referred to. 



Foreign countries have suffered severety under the scourge 

 of swarms of voles nearly akin to, though some of them not 

 identical with, the British species. Simultaneously with the 

 outbreak in Roxburghshire in 1875-76, the corn-lands of Galicia 

 and Hungary were infested by swarms of Arvicola arvalis. 



During 1891-92 the province of Thessaly was invaded by a 

 plague of rodents, supposed at first to be Arvicola Savii, but 

 subsequently identified as Arvicola Guntheri (Danford, Proc. 

 Zool. Soc. 1880, p. 62, pi. v.). 



In the American continent, also, the land is subject to similar 

 visitations. In his * Naturalist in La Plata,' Mr. W. H. Hudson 

 gives a graphic description of the Pampas being overrun by 

 swarms of a species of Field Mouse (Hesperomys), and mentions 

 the usual concomitant of extraordinary numbers of Short-eared 

 Owls which preyed upon them. In this, as in most of the 

 instances recorded, there is evidence to show that the voles 

 disappeared rapidly, almost suddenly, whether from stress of 

 weather, epizootic disease, or other causes. 



Natural Enemies of the Vole. — No phenomenon in connection 

 with the present plague of Field Voles in Scotland has been more 

 marked than the presence of large numbers of the Short-eared 

 Owl, Otus brachyotus. This bird, which is distributed over almost 

 every part of the globe, is a normal winter migrant to these islands, 

 appearing simultaneously with the Woodcock (whence it is popu- 

 larly known as the " Woodcock Owl"), and usually departing in 

 spring. Nests in ordinary seasons are of comparatively rare 

 occurrence in Great Britain ; but in consequence of the vast 

 multiplication of their favourite food, the vole, these Owls have 



