OF SELBORNE 143 



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 prudentia to a simple bird. 

 Mav 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 irntans), swarming at the 

 mouths of these holes, like bees on the stools of their hives. 1 



The following circumstance should by no means be omitted 

 that these birds do not make use of their caverns by way of 

 hybernacula, as might be expected ; since banks so perforated 

 have been dug out with care in the winter, when nothing was 

 found but empty nests. 



The sand-martin arrives much about the same time with the 

 swallow, and lays, as she does, from four to six white eggs. But 

 as this species is cri/ptogame, carrying on the business of nidifica- 

 tion, incubation, and the support of it's young in the dark, it 

 would not be so easy to ascertain the time of breeding, were it 

 not for the coming forth of the broods, which appear much about 

 the time, or rather somewhat earlier than those of the swallow. 

 The nestlings are supported in common like those of their 

 congeners, with gnats and other small insects ; and sometimes 

 they are fed with libellulce (dragon-flies) almost as long as them- 

 selves. In the last week in June we have seen a row of these 

 sitting on a rail near a great pool as perchers ; and so young and 

 helpless, as easily to be taken by hand : but whether the dams 

 ever feed them on the wing, as swallows and house-martins do, 

 we have never yet been able to determine ; nor do we know 

 whether they pursue and attack birds of prey. 



When they happen to breed near hedges and enclosures, they 



1 [The flea of the sand-martin is distinct, not only from the bed-flea, but from 

 the flea of the swallow. ] 



