202 
NATURAL HISTORY 
LETTER XXL 
TO THE HONOURABLE DAINES BAKRINGTON. 
Selborne, Sept. 28, 1774. 
S tlie swift or black martin is the largest of 
the British Hirundines, so is it 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 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 remembering 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 mate- 
rials 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 middle of 
May ; and I have remarked, from eggs taken, that they have 
sat hard by the 9th of June. In general they haunt tall 
buildings, churches, and steeples, and breed only in such : yet 
