62 NATURAL HISTORY OF SELBORXE. 



for the quadrupeds of Britain are so few, that every new species is a 

 great acquisition. 



The eagle-owl, could it be proved to belong to us, is so majestic a 

 bird, that it would grace our fauna much. I never was informed before 

 where wild-geese are known to breed. 



You admit, I find, that I have proved your fen salicaria to be the 

 lesser reed-sparrow of Ray ; and I think you may be secure that I am 

 right, for I took very particular pains to clear up that matter, and 

 had some fair specimens ; but, as they were not well preserved, they 

 are decayed already. You will, no doubt, insert it in its proper place in 

 your next edition. Your additional plates will much improve your work. 



De Buffon, I know, has described the water shrew-mouse : but still I 

 am pleased to find you have discovered it in Lincolnshire, for the reason 

 I have given in the article of the white hare. 



As a neighbour was lately ploughing in a dry chalky field, far 

 removed from any water, he turned out a water-rat, that was curiously 

 lain up in an hybernaculum artificially formed of grass and leaves. At 

 one end of the burrow lay above a gallon of potatoes regularly stowed, 

 on which it was to have supported itself for the winter. But the 

 difficulty with me is how this amphibius mus came to fix its winter 

 station at such a distance from the water. Was it determined in its 

 choice of that place by the mere accident of finding the potatoes which 

 were planted there ; or is it the constant practice of the aquatic rat to 

 forsake the neighbourhood of the water in the colder months 1 



Though I delight very little in analogous reasoning, knowing how 

 fallacious it is with respect to natural history ; yet, in the following 

 instance, I cannot help being inclined to think it may conduce towards 

 the explanation of a difficulty that I have mentioned 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 by is at present a nondescript in 

 England,f 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, orphalcence, 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 curlews clamoured on to October 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 : are a rare species with us. 



t See also Letters XXII., XXXVI., and note. 



