154 THE SECOND BOOK OF BIRDS 
It is a beautiful thing to see a large flock of 
swifts go to bed. If they all rushed in pell-mell, 
they might hurt one another. They begin by 
flying around high above the chimney in great 
circles. As they go around they sink lower, and 
the circles get smaller till it looks hke an im- 
mense whirling funnel. When the birds form- 
ing the lower part of the funnel reach the top of 
the chimney, they plunge in. So in a short time 
the whole flock is in and no one hurt. 
