196 The Natural History 



so numerous, and so widely distributed over the village, 

 that it is hardly possible to recount them ; while the 

 swifts, though they do not all build in the church, yet so 

 frequently haunt it, and play and rendezvous round it, 

 that they are easily enumerated. The number that I 

 constantly find are eight pairs ; about half of which reside 

 in the church, and the rest build in some of the lowest 

 and meanest thatched cottages. Now as these eight 

 pairs, allowance being made for accidents, breed yearly 

 eight pairs more, what becomes annually of this increase ; 

 and what determines every spring which pairs shall visit 

 us, and reoccupy their ancient haunts ? 



Ever since 1 have attended to the subject of ornithology, 

 I have always supposed that that sudden reverse of affec- 

 tion, that strange di/rto-Topy^, which immediately succeeds 

 in the feathered kind to the most passionate fondness, is 

 the occasion of an equal dispersion of birds over the face 

 of the earth. Without this provision one favourite dis- 

 trict would be crowded with inhabitants, while others 

 would be destitute and forsaken. But the parent birds 

 seem to maintain a jealous superiority, and to oblige the 

 young to seek for new abodes : and the rivalry of the 

 males, in many kinds, prevents their crowding the one 

 on the other. Whether the swallows and house-martins 

 return in the same exact number annually is not easy to 

 say, for reasons given above : but it is apparent, as I 

 have remarked before in my Monographies, that the 

 numbers returning bear no manner of proportion to the 

 numbers retiring. 



LETTER XL 



TO THE HONOURABLE DAINES HARRINGTON 



Selborne, June 2, 1778. 



Dear Sir, 



The standing objection to botany has always been, that 

 it is a pursuit that amuses the fancy and exercises the 

 memory, without improving the mind or advancing any 



