172 NATURAL HISTORY OF SELBORNE. 



These hirundines are no songsters, but rather mute, 

 making only a little harsh noise when a person approaches 

 their nests. They seem not to be of a sociable turn, never 

 with us congregating with their congeners in the autumn. 

 Undoubtedly they breed a second time, like the house- 

 martin and swallow ; and withdraw about Michaelmas. 



Though in some particular districts they may happen to 

 abound, yet in the whole, in the south of England at least, 

 is this much the rarest species. For there are few towns or 

 large villages but what abound with house-martins ; few 

 churches, towers, or steeples but what are haunted by some 

 swifts; scarce a hamlet or single cottage-chimney that has not 

 its swallow; while the bank-martins, scattered here and there, 

 live a sequestered life among some abrupt sand-hills, and in 

 the banks of some few rivers. 



These birds have a peculiar manner of flying ; flitting 

 about with odd jerks and vacillations, not unlike the 

 motions of a butterfly. Doubtless the flight of all hirun- 

 dines is influenced by, and adapted to, the peculiar sort 

 of insects which furnish their food. Hence it would be 

 worth inquiry to examine what particular genus of insects 

 affords the principal food of each respective species of 

 swallow. 



Notwithstanding what has been advanced above, some 

 few sand-martins, I see, haunt the skirts of London, 

 frequenting the dirty pools in Saint George's Fields, and 

 about Whitechapel. The question is where these build, 

 since there are no banks or bold shores in that neighbour- 

 hood ; perhaps they nestle in the scaffold holes of some old 

 or new- deserted building. They dip and wash as they fly 

 sometimes, like the house-martin and swallow. 



Sand-martins differ from their congeners in the diminu- 

 tiveness of their size, and in their colour, which is what 



