COMMON FLYING SQUIRREL. 153 



appearance by day^ emerging only at the com- 

 mencement of twilight, when it may be seen 

 climbing about the trees, and darting with great 

 velocity from one to the other. The colour of 

 its upper part so much resembles that of the pale 

 silvery bark of the birch-trees which it frequents, 

 that it is by no means easy to distinguish it, 

 while engaged in climbing about during its even- 

 ing exercise. It feeds chiefly on the young 

 shoots^ buds, and catkins of the birch, as well as 

 on those of the pine, &c. In winter it continues 

 in its nest ; coming out only in mild weather ; 

 but does not become torpid during that season. 



This animal readily springs to the distance of 

 twenty fathoms or more^ and by this motion con- 

 veys itself from the top of one tree to the middle 

 part of that to which it directs it flight, which is 

 always slightly downwards. It very rarely de- 

 scends to the surface, and, when taken, and 

 placed on the ground, runs or springs somewhat 

 awkwardly, with its tail elevated, and as soon as 

 it gains a tree, instantly begins to climb it with 

 great activity, sometimes elevating, and some- 

 times depressing its tail. If thrown from the top 

 of a tree, it immediately spreads it membranes, 

 and, balancing itself, endeavours to direct its 

 motion by the assistance of the tail. The young 

 are produced about the beginning or before the 

 middle of May, and are two, three, and some- 

 times four, in number : they are at first blind, and 

 nearly void of hair ; and the parent fosters them 

 by covering them with her flying-membrane ; 



