CH. II.] SWALLOWS KILLED BY PARASITES. 165 



were crowded with young Martins as many per- 

 haps as four or five in each sunning their barred 

 white breasts, and waiting to be fed : the telegraph 

 wires formed perches, of which advantage was 

 taken by scores of others more advanced in 

 growth, and of old ones reposing after their exer- 

 tions; while the air was filled with others em- 

 ployed in catering for their families. All of a 

 sudden the young ones retreated into their holes ; 

 the wires were deserted, and only a few remained 

 visible describing distant circles. I thought that 

 a Hawk must have made his appearance, but it 

 turned out that the alarm had been caused by two 

 men walking over the heath above, and approach- 

 ing the holes. The young ones in the holes had, 

 no doubt, felt the jar caused by their tread, and 

 those on the wing, who saw them, had probably 

 given warning, by note, to the others perched on 

 the wires, who could not have seen, nor, I should 

 think, heard their approach. 



Two well-authenticated instances have come 

 within my knowledge in which Swallows have, 

 while in the act of flying, fallen to the ground co- 

 vered with and partly devoured by insects. Of the 

 fact there seemed to be no doubt, but the descrip- 

 tion of the insects furnished me by my informants 



