136 ^The Natural History of Se I borne 



Swallows and martins, the bulk of them I mean, have for- 

 saken us sooner this year than usual ; for on September the 

 twenty-second they rendezvoused in a neighbour's walnut-tree, 

 where it seemed probable they had taken up their lodging for 

 the night. At the dawn of the day, which was foggy, they 

 arose all together in infinite numbers, occasioning such a 

 rushing from the strokes of their wings against the hazy air, 

 as might be heard to a considerable distance : since that no 

 flock has appeared, only a few stragglers. 



Some swifts stayed late, till the twenty-second of August 

 a rare instance ! for they usually withdraw within the first 

 week.* 



On September the twenty-fourth three or four ring-ousels 

 appeared in my fields for the first time this season ; how 

 punctual are these visitors in their autumnal and spring 

 migrations ! 



* See Letter LIII. to Mr. Harrington. 



