The Natural History of Selborne 225 



to no purpose from summer to summer, without changing 

 their aspect or house. It is a piteous sight to see them 

 labouring when half their nest is washed away and bringing 

 dirt . . . "generis lapsi sarcire rut'nas." Thus is instinct a 

 most wonderful unequal faculty; in some instances so much 

 above reason, in 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 close 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 sweep- 

 ing long 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 hol- 

 low vale, especially in windy weather. They breed the latest 

 of all the swallow kind: in 1772 they had nestlings on to 

 October 2ist, and are never without unfledged young as late 

 as Michaelmas. 



As the summer declines, the congregating flocks increase 

 in numbers daily by the constant accession of the second 

 broods; till at last they swarm in myriads upon myriads 

 round the villages on the Thames, darkening the face of the 

 sky as they frequent the aits [eyots] 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 late as November the 3rd and 6th, after they 

 were supposed to have been gone for more than a fortnight. 

 They therefore withdraw with us the latest of any species. 

 Unless these birds are very short-lived indeed, or unless they 

 do not return to the district where they are bred, they must 



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