96 VESPERTILIONID^— NYCTALUS 



destination ; which shows that they range to some distance in 

 search of food. They are fond of frequenting cattle pastures ; 

 but here not only, like the Noctule, do they vary their hunting- 

 grounds with the season, but also with the hour, having 

 apparently regular feeding-grounds both for the early and late 

 parts of the evening. Thus the pasture attracts them to a 

 certain extent from May to September ; but until midsummer, 

 when the cattle occupy it, the bats fly in it for only a few 

 minutes each evening, just before retiring for the night. 

 During the late summer months the half-hour before retire- 

 ment is spent in careering about the field. 



Dr Alcock writes of this bat^ that "at first it commonly 

 flies at a considerable height, in open country taking long 

 sweeps and wide zigzags, often being seen but once in an 

 evening. Near woods and in favourable localities it will often 

 remain for some little time neaf one spot, flying at an altitude 

 of 30 to 40 feet, with a faster and less irregular flight than the 

 Pipistrelle, the tail being extended at a straight line with the 

 body. Later on, it flies near the ground, very commonly 

 shrieking loudly, and I have observed two Bats at this time 

 chasing one another . . . both flying very fast, and screaming." 



Mr Moffat has observed a curious peculiarity of the flight. 

 When a bat is hunting insects at a considerable elevation, 

 the observer who is high enough, say, on a hillside, to secure a 

 horizontal view of it, may notice that its motions consist of a 

 regular succession of very gradual ascents and abrupt descents, 

 Mr Moffat suggests that the descent is merely a means of 

 keeping the bat in the plane where its favourite food abounds ; 

 at all events the regularity of the process is very striking, and 

 leads almost to the inference that they may be additional to 

 those already described movements of similar regularity in the 

 Noctule which Tomes has otherwise interpreted. 



According to Mr Moffat, the cry of Leisler's Bat, when 

 flying in company, is a shrill strong screech, which he judges, 

 although without opportunity of actual comparison, to be 

 shriller and stronger than that of the Noctule. There is 

 besides "a peculiar 'tinkling' song emitted by a single bat 

 when flying alone ; when a second appears it is greeted with 



' Irish Naturalist, 1899, 169-174, and map. 



