LETTER XXI 



TO THE SAME 



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 it's 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 

 architecture, making no crust, or shell, for it's 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 carrying 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 re- 

 membering that I have seen them squabbling 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 nidifi- 

 cation quite in the dark, in crannies of castles, and towers, 

 and steeples, and upon the tops of the walls of churches 

 under the roof ; and therefore cannot be so narrowly 

 watched as those species that build more openly : but, from 

 what I could ever observe, they begin nesting about the 



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