210 BRITAIN'S BIRDS AND THEIR NESTS. 



than ever, screaming their loudest. Then, apparently, 

 they seek the shelter of their nesting-holes. But some- 

 times they have been observed to circle gradually upwards 

 to an immense height, being lost in the gathering 

 dusk. Patient waiting long after nightfall has failed to 

 betray any sign of the returning birds. The matter must 

 be considered an unexplained mystery ; but some have 

 been bold enough to suggest that those Swifts not engaged 

 in incubation cap the species'* reputation by sleeping on 

 the wing ! 



The long wings and the peculiar feet of this species 

 make it a bird unsuited for level ground, on which it is 

 indeed but seldom seen. But of it a great authority wrote 

 that, 'contrary to popular belief, birds sometimes succeed 

 in raising themselves from fairly level ground.' We our- 

 selves have known one rise without sign of difficulty from 

 absolutely level ground. This was when one flew in at our 

 window, got entangled in a curtain, and was thus captured. 

 Placed on the carpet, it rose without difficulty, and flew 

 round the room before being allowed to escape. A 

 popular writer remarks that he has 'caught a few, a very 

 few, in the act of dusting themselves in Kentish lanes, 

 from which, in spite of the length of their wings, they 

 can rise without quite so much difficulty as some chroniclers 

 would have us imagine."* On the other hand, we have 

 the testimony of many competent observers that they 

 have placed Swifts on the ground, and found them imable 

 to rise in spite of great efforts. Part of the explanation 

 lies perhaps in the following statement, made after a score 

 of trials : ' Drop him from a little height on to the 

 ground, and he will often manage, with a sort of re- 

 bound, to flutter up at once ; but lay him gently on 

 rough ground or grass, hold your hand over him for a 

 minute, and his muscles will become cramped, and he will 



