50 



MAMMALS. 



Family MURID^. 



Mus sylvaticus, Z. Long-tailed Field Mouse. 



There remains scarcely any doubt as to its universality of distribution 

 both in time and area, though actual records are not absolute nor 

 efficient for the earlier data. Their distribution is now at all events 

 very general even to summits of considerable altitude. Thus, as 

 long ago as 1848 Mr. Archibald Hepburn records that he found it 

 on the top of Mam Soul in Inverness-shire, i.e. between three and 

 four thousand feet above the sea (Zool, 1848, 2010, etc.). It is 

 found also almost down to sea-level, and in all carse and dry-field 

 lands. In some seasons they are very much more abundant than in 

 others, like many of our smaller mammalia which are capable of 

 frequent birth-giving and procreating large families.^ 



To take recent instances of unusual increases, either locally or 

 generally, 1898 was a year when they did great damage in north-east 

 Forfarshire. Mr. Milne relates that he killed seventeen in a green- 

 house adjacent to an aviary, the " beasties " having no doubt been 

 attracted by bird-seed lying about. This is no uncommon experi- 

 ence, but varying only with the seasons. The Long-tailed Field 

 Mouse or Wood Mouse is quite as much a frequenter of gardens and 

 vineries, and stables and outhouses, but is less commonly captured 

 within dwelling-houses — in fact, anywhere that feeding is most avail- 

 able in winter. The Field Mouse becomes the Steading Mouse about 

 October or November, after the growth outside ceases or the supply 

 of outside food begins to fail. This change of habit may even take 

 place by the end of September in some seasons. They increase in 

 numbers just as we have early or late approach of winter, or an early 

 husbanded or a late harvest. 



^ There are many interesting notes in this connection by Herr Prof. Robert Collett 

 of Christiania, which are well worthy of consultation, whether in regard to the migra- 

 tions and periodical increases of the Lemming in Norway {Lemmus norvegicus) , or of 

 other small mammals. 



This paper gives, amongst other matter, a list of the greater Lemming years in 

 Norway. And it will be found valuable and interesting to such as may take the 

 trouble of "putting two and two together," not only as regards Lemming and Vole 

 plagues, but also as regards the periodical visits to this country of certain birds of prey 

 — such, for instance, as those of the Rough-legged Buzzard, etc., q.v. infra. 



