OF SELBORNE. 193 
some instances so much above reason, iu other 
respects so far below it! Martins love to frequent 
towns, especially if there are great lakes and rivers 
at hand; nay, they even affect the cluse air of 
London. And I have not only seen them nesting 
in the Borough, but even in the Strand and Fleet- 
street ; but then it was obvious, from the dinginess 
of their aspect, that their feathers partook of the 
filth of that sooty atmosphere. Martins are by far 
the least agile of the four species ; their wings and 
tails are short, and therefore they are not capable 
of such surprising turns, and quick and glancing 
evolutions, as the swallow. Accordingly, they 
make use of a placid, easy motion, in a middle 
region of the air, seldom mounting to any great 
height, and never sweeping along together over the 
surface of the ground or water. They do not 
wander far for food, but affect sheltered districts, 
over some lake, or under some hanging wood, or 
in some hollow vale, especially in windy weather. 
They build the latest of all the swallow kind: in 
1772 they had nestlings on to October: the 2I1st, 
and are never without unfledged young as late as 
Michaelmas. 
As the summer declines, the congregating flocks 
increase in numbers daily by the constant succes. 
sion of the second broods, till at last they swarm 
in myriads upon mysiads round the villages on the 
Thames, darkening the face of the sky as they fre- 
quent the aits of that river, where they roost. 
They retire—the bulk of them, I mean—in vast 
flocks together, about the beginning of October ; 
but have appeared, of late years, in a considerable 
flight in this neighbourhood, for one day or two, as 
R 
