SWIFTS. 237 



LETTEE LXXXI. 



TO THE SAME. 



SELBORNE, May 13, 177o. 



DEAR SIB, Among the many singularities attending those 

 amusing birds, the swifts, I am now confirmed in the* opinion 

 that we have every year the same number of pairs invariably; 

 at least the result of my inquiry has been exactly the same 

 for a long time past. The swallows and martins are 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 

 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 re-occupy their ancient haunts ? * 



Ever since I have attended to the subject of ornithology, 

 I have always supposed that the sudden reverse of affection, 

 that strange avria-ropyrj, which immediately succeeds in the 

 feathered kind to the most passionate fondness, is the occa- 

 sion of an equal dispersion of birds over the face of the earth. 

 "Without this provision, one favourite district 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. Whe- 

 ther the swallows and house-martins return in the same 

 exact number annually is not easy to say, for reasons given 



* Swift8, swallows, and martins are perhaps, from their rapid flight, less 

 preyed upon than any other small hirds. Numbers of them undoubtedly 

 perish during the progress of their two annual migrations. ED. 



