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OBSERVATIONS ON THE NOCTULE. 

 By Charles Oldham. 



In the neighbourhood of Alderley Edge, and, indeed, through- 

 out the wooded parts of the Cheshire Plain, the Noctule, Pipi- 

 strellus noctula iSchreb.), is abundant, A hollow tree, or less 

 frequently a house=roof, serves as a diurnal retreat, whence, 

 during the warmer months, the Bats issue to feed soon after the 

 daylight has begun to wane. On fine summer evenings one's 

 attention is often attracted by the shrill squeak of the Noctules 

 which are flying in company with the Swifts, at an altitude diffi= 

 cult to estimate accurately, but certainly not less than from 

 seventy to eighty feet. This squeaking note is pitched so high 

 that it is inaudible to many ears. As the light fades, the Bats 

 descend to a lower level, and feed at a height of from fifteen to 

 thirty or forty feet above the fields, pools, and open places in the 

 woods. The crunching of their jaws as they masticate their 

 insect prey may then be heard distinctly. 



The time at which the Noctule issues from its retreat does 

 not always bear the same relation to the hour of sunset, and 

 sometimes differs considerably on consecutive evenings. Wind, 

 temperature, and other atmosplieric conditions, rather than the 

 actual hour of sunset, probably determine the time at which the 

 Bats emerge, and the duration of their flight. Rain, if not 

 heavy, does not incommode them whilst feeding, but if the night 

 be cold and windy few or none will be seen. It is probable that 

 individual Noctules do not alwa)'s resort to the same den through- 

 out the summer, for the numbers which emerge in the evening 

 are not constant, and even on consecutive evenings, when the 

 atmospheric conditions appear to be identical, the number some- 

 times varies considerably. On the other hand, it is possible that 

 on some evenings the whole strength of the colony does not turn 

 out, and that some of the Bats remain in the den all night. 



On April 5th, 1896, Mr. T. A. Coward and I watched Noctules 

 sallying forth for their evening flight from a hole beneath the 



