^905- Moffat. — Diuation of Flight among Bats. loi 



nioiily placed it in the vSame genus with the Hairy-armed Bat 

 and the Noctule, and from that we might expect that its 

 habits would not greatly differ from theirs. So, though one 

 good naturalist, William Macgillivray, said long ago, in his 

 " History of British Quadrupeds," that it probably flies all 

 night, it is not, perhaps, very surprising that since that time 

 other naturalists have almost unanimously contradicted him, 

 and asserted that it probably flies only in the evening. 

 However, the net result of my observations on the Pipistrelle 

 is that it really flies all night. On an average, it is only 

 about seven minutes later than the Hair}' -armed Bat about 

 starting on its flight in the evening, and it is equally late 

 with the Hairy-armed Bat in returning to its retreat in the 

 morning ; but the difference between them is that the 

 Pipistrelle has been out the whole of the intermediate time, 

 while the Hairy-armed Bat, putting his evening and morning 

 flights together, has not been out for much more than a quarter 

 of it. These facts seem to me so singular, that I think the 

 evidence for them should be made plain. 



Of course, in observing Bats, one must be very careful 

 that one knows what sort of Bat one is observing. The diffi- 

 culty of being quite certain on that point vitiates a good 

 many observations that might otherwise be useful. However, 

 I began my inquiries into the Pipistrelle's habits by passing 

 a night in the open air in bright moonlight, in a spot where 

 large numbers of bats generally fly. The result of this pre- 

 Hminar}^ mode of inquiry (on the night of August 2ist-22nd, 

 1899) was that I found that there were lots of Bats visible on 

 the wing at all hours throughout the night, as well as in the 

 clear light of early morning. That was not conclusive, 

 because, in the first place, these Bats might not all have been 

 Pipistrelles, and, even if they were, some might have gone 

 home early and others come out late, so that there was no 

 proof that any individual Bat, Pipistrelle or otherwise, had 

 been flying about the whole time. The next thing to do was, 

 therefore, to find out where some of these Bats went in the 

 morning. By watching on several mornings, in the summers 

 of 1899 and 1900, I ultimately got the retreats of half a dozen, 

 each living a perfectly solitary life in a little den of its own — 

 some in holes in walls, and some in the trunks of trees. 



