84 



NATURAL HISTORY OF SELBORNE. 



Common Swift. 



there ; or is it the constant practice of the aquatic-rat to forsake 

 the neighbourhood of the water in the colder months ? 



Though I delight very little in analogous 

 reasoning, knowing how fallacious it is with 

 respect to natural history ; yet, in the fol- 

 lowing instance, I cannot help being in- 

 clined to think it may conduce towards the 

 explanation of a difficulty that I have men- 

 tioned before, with respect to the invariable 

 early retreat of the hirundo apus, or swift, 

 so many weeks before its congeners; and 

 that not only with us, but also in Andalusia, 

 where they also begin to retire about the 

 beginning of August. 



The great large bat* (which by the bye is at present a non- 

 descript in England, and what I have never been able yet to 

 procure) retires or migrates very early 

 in the summer : it also ranges very 

 high for its food, feeding in a different 

 region of the air; and that is the 

 reason I never could procure one. 

 Now this is exactly the case with the 

 swifts ; for they take their food in a 

 more exalted region than the other 

 species, and are very seldom seen 



hawking for flies near the ground, or over the surface of the 

 water. From hence I would conclude that these hirundines, and 

 the larger bats, are supported by some sorts of high-flying gnats, 

 scarabs, or phalcenee, that are of short continuance ; and that the 

 short stay of these strangers is regulated by the defect of their 

 food. 



By my journal it appears that curlewsf clamoured on to Octo- 

 ber the thirty-first ; since which I have not seen or heard any. 

 Swallows were observed on to November the third. 



* The little bat appears almost every month in the year ; but I have never seen the large ones 

 till the end of April, nor after July. They are most common in June, but never in any plenty, 

 being a rare species with us. The pipistrel bat (V. pipistrella) is the species seen on the wing 

 at all seasons. ED. * 



t Thicknees (cedicnemus JEui'opaiw) are of course here intended, the curlew genus (numtnius 

 being very distinct. ED. 



