CONCERNING SWIFTS 163 



were hawking for flies, but they went in before 9.20. Two 

 also were out, but soon retired, on the north side of the 

 church, where my father and brother kept watch alter- 

 nately. Not one of the high-fliers came back. Many bats 

 came out from under the eaves ; I could see the moths 

 and beetles against the sky ; but those swifts stayed up 

 aloft. On other nights we watched, but not quite con- 

 tinuously, until eleven o'clock, and satisfied ourselves that 

 the swifts did not return." 



In the same month of 1887, the late Mr. 

 Douglas Brodie, of Croydon, also observed the 

 night-flight of the swift, and afterwards wrote to 

 the Field about it (Field, May 18, 1889). He 

 noticed the peculiar quivering of the birds' wings 

 during the ascent. 



Probably the reason why this wonderful habit 

 of the swift was so long overlooked may be found 

 in the fact that it can only be observed at one 

 particular time, and that five minutes earlier or later 

 there is nothing of special interest to be observed. 



After sunset the swifts continue for a while 

 their noisy pursuit of each other about the level of 

 the roofs ; and presently the birds do the same 

 thing at a slightly higher elevation, and traverse a 

 wider area, so that they are often out of sight for 



