MofpaT. — Duration of Flight aviong Bats, 103 



Now there could be no doubt, in the case of that animal, that 

 it had been out all night. All that remained was to make 

 sure — a very important matter — that I was right concerning 

 its species ; so the next evening I set the net again over the 

 same hole, caught the Bat as it came out, and found that it 

 was a male Pipistrelle. 



The above experiment was made on a fine bright night, so 

 I thought it safer to try it again on another Bat under less 

 comfortable conditions, choosing, this time, a dark and foggy 

 night, when nobody could suppose that Bats would be 

 specially tempted to fly late. Such a night occurred on 

 August 30th, 1900, when I netted the residence of a second 

 Pipistrelle. The result, however, was just the same as in the 

 former case. No Bat came out after midnight ; but, at the 

 usual time before sunrise, the occupant of the hole went in. 

 Hence, it follows that even during raw and foggy nights, 

 when insects might be presumed scarce, the Pipistrelle does 

 not retire into its den, but continues abroad till its usual hour 

 for seeking sanctuary in the twilight of the early morning. 

 I even find that the same thing happens in winter when the 

 nights are warm enough for the Pipistrelle to fly. I have 

 several times seen it at midnight in the long nights of 

 December and January, and though I have not stayed out at 

 that season to see it going home at seven or eight o'clock in the 

 morning, I have trustworthy information from one whose 

 vocation brings him out at those hours (Mr. James Kelly, 

 Ballyhyland), that it stays on the wing till nearly daylight — 

 in other words, flies through a sixteen hours' night. 



Now surely this animal must differ more than is commonly 

 supposed, in point of structure and relationship, from creatures 

 like the Hairy-armed Bat and Noctule, which feed fast and 

 furiously for a short hour or so, and then sink into lethargy 

 like the sleep of winter. The contrast is rendered greater 

 when we consider the disparity in size. The Pipistrelle, being 

 less than one-third of the weight and bulk of the Hairy- 

 armed Bat, or one-fifth that ol the Noctule, cannot in the 

 nature of things require nearly so much food as these 

 animals do ; yet it allows itself the whole night to collect the 

 lesser quantity, while each of its formidable cousins despatches 

 the greater in little less than an hour. 



