349 



THE FLIGHT OF BATS. 



(plate XXVII.) 



ARTHUR WHITAKER, 



U'orsbroiigh Bridge. 



I AM frequently asked by some friend if I can say to what 

 species a particular bat should be referred which has been 

 observed flying- at dusk. Although it is a difficult matter 

 to be perfectly certain about the identity of a bat under these 

 circumstances, nevertheless, after a good many years spent in 

 studying these creatures, I can now often feel pretty confident 

 as to species of bats which I see on the wing. 



As the characteristics of flight and haunt which enable one 

 to recognise some species even in the twilight, are not difficult 

 to point out, it struck me that a short article on this subject 

 might not be without interest to readers of the ' Naturalist,' 

 and might enable them to get a better idea as to what species 

 of bats occur in their own immediate neighbourhood. 



The Noctule {Pterygister nochila) is not difficult to recognise. 

 In the first place it is the largest Yorkshire species, the wings 

 having an expanse of from thirteen to fifteen inches. The 

 wings are long, narrow, and pointed ; the flight strong, rapid, 

 and sustained. This bat is undoubtodly the most powerful on 

 the wing of any British species. 



It makes its appearance very early in the evening-, usually 

 fifteen or twenty minutes earlier than any other species. It 

 occasionally comes out even before sunset, but more often 

 appears ten or fifteen minutes afterwards. In July and August 

 it will often be noticed that the appearance of these bats on the 

 wing almost exactly coincides with the disappearance of the 

 swifts for the evening-. Our attention is almost invariably 

 first attracted to it by its piercing-, sibilant, and somewhat 

 ventriloquial note, high overhead. High though it flies, it is 

 not difficult to see, for it commences its flight almost before it 

 can be called dusk, and when there is still plenty of light by 

 which to discern it. The Noctule is the highest flying of our 

 bats, and it is nothing unusual for it to be seen wheeling about 

 at an altitude of two or even three hundred feet. 



If it be carefully watched for a short time, two peculiarities 

 of its flight cannot fail to strike the observer. 



Firstly, a habit it has when flying in a straight line, of doing- 



1906 October i. 



