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 of this annual 

 increase ; and what determines every spring which 

 pairs shall visit us, and reoccupy their ancient haunts? 

 Ever since 1 have attended to that subject of 

 ornithology, I have always supposed that the sud- 

 den reverse of affection, that strange avroaropyrj, or 

 antipathy, which immediately succeeds in the feath- 

 ered 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 fa- 

 vourite district would be crowded with inhabitants, 

 while others would be destitute and forsaken. But 

 the parent birds seem to maintain a jealous supe- 

 riority, 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. 



Selborne, May 13, 1778. 



98 



