The Natural History of Selborne

I saw two swifts, entangled with each other, fall out of their nest to the ground, from whence they soon rose & flew away.  This accident was probably owing to amorous dalliance.  Hence it appears that swifts when down can rise again.  Swifts seen only morning & evening: the hens probably are engaged all the day in the business of incubation;  while the cocks are roving after food down to the forest, & lakes.  These birds begin to sit about the middle of this month, & have squab young before the month is out.