NATURAL HISTORY OF SELBORNE 147 



ing. They dip and wash as they fly sometimes, like the house- 

 martin and swallow. 



Sand-martins differ from their congeners in the diminutive- 

 ness of their size, and in their color, which is what is usually 

 called a mouse-color. Near Valencia, in Spain, they are taken, 

 says Willughby, and sold in the markets for the table ; and 

 are called by the country-people, probably from their desul- 

 tory jerking manner of flight, Papilion de Montagna. 



NOTE 



1 This insect is not the bed-flea, but another, distinct also from those 

 which trouble the swallow and the swift. G. C. D. 



LETTER XXI 



SELBORNE, Sept. 28^, 1774. 



DEAR SIR, As the swift or black-martin is the largest of 

 the British hirundines, so it is undoubtedly the latest comer. 

 For I remember but one instance of its appearing before the 

 last week in April; and in some of our late frosty, harsh 

 springs, it has not been seen till the beginning of May. This 

 species usually arrives in pairs. 



The swift, like the sand-martin, is very defective in archi- 

 tecture, making no crust, or shell, for its nest ; but forming it 

 of dry grasses and feathers, very rudely and inartificially put 

 together. With all my attention to these birds, I have never 

 been able once to discover one in the act of collecting or carry- 

 ing in materials ; so that I have suspected (since their nests 

 are exactly the same) that they sometimes usurp upon the 

 house-sparrows, and expel them, as sparrows do the house and 

 sand martin ; well remembering that I have seen them squab- 

 bling together at the entrance of their holes, and the sparrows 

 up in arms, and much disconcerted at these intruders. And 

 yet I am assured, by a nice observer in such matters, that 

 they do collect feathers for their nests in Andalusia, and that 

 he has shot them with such materials in their mouths. 



Swifts, like sand-martins, carry on the business of nidifica- 



