246 T'/ie Natural History of Selborne 



which is serpentine, horizontal, and about two feet deep. At 

 the inner end of this burrow does this bird deposit, in a good 

 degree of safety, her rude nest, consisting of fine grasses and 

 feathers, usually goose-feathers, very inartificially laid together. 



Perseverance will accomplish anything, though at first one 

 would be disinclined to believe that this weak bird, with her 

 soft and tender bill and claws, should ever be able to bore 

 the stubborn sand-bank without entirely disabling herself; 

 yet with these feeble instruments have I seen a pair of them 

 make great despatch, and could remark how much they had 

 scooped that day by the fresh sand which ran down the bank, 

 and was of a different colour from that which lay loose and 

 bleached in the sun. 



In what space of time these little artists are able to mine 

 and finish these cavities I have never been able to discover, 

 for reasons given above ; but it would be a matter worthy of 

 observation, where it falls in the way of any naturalist to 

 make his remarks. This I have often taken notice of, that 

 several holes of different depths are left unfinished at the 

 end of summer. To imagine that these beginnings were 

 intentionally made in order to be in the greater forwardness 

 for next spring is allowing perhaps too much foresight and 

 rerum prudenlia to a simple bird. May not the cause of these 

 latebrce being left unfinished arise from their meeting in those 

 places with strata too harsh, hard, and solid for their purpose, 

 which they relinquish, and go to a fresh spot that works more 

 freely ? Or may they not in other places fall in with a soil 

 as much too loose and mouldering, liable to flounder, and 

 threatening to overwhelm them and their labours ? 



One thing is remarkable that, after some years, the old 

 holes are forsaken and new ones bored ; perhaps because the 

 old habitations grow foul and fetid from long use, or because 

 they may so abound with fleas as to become untenantable. 

 This species of swallow, moreover, is strangely annoyed with 

 fleas ; and we have seen fleas, bed-fleas (pulex irritans)^ 



1 White is here mistaken. The flea which infests the sand-martin is a 

 special species. ED. 



