THE CHIMNEY SWIFT 57 



it will be noticed that he spreads his tail for an 

 instant whenever he changes suddenly the direc- 

 tion of his flight. In other words, he uses his 

 tail as a rudder. 



He shoots about the sky at a tremendous 

 speed, much of the time sailing, with his long, nar- 

 row wings firmly set, and is especially lively and 

 noisy toward nightfall. Very commonly two or 

 three of the birds fly side by side, cackling 

 merrily and acting very much as if they were 

 amusing themselves with some kind of game. 



They feed on the wing, and have wide, gaping 

 mouths perfectly adapted to that purpose. 



As their name implies, they build their nests 

 and pass the night mostly in chimneys, although 

 in the wilder parts of the country they still 

 inhabit hollow trees. Numbers of pairs live 

 together in a colony. 



One of the chimneys of a certain house near 

 the Charles River, in Newton, Massachusetts, has 

 for many years been a favorite resort of swifts. 

 I have many times visited the place to watch the 

 birds go to roost. Little by little they gather in 

 a flock, as twilight comes on, and then for an 

 hour or more the whole company, hundreds in 

 number, go sweeping over the valley in broad 

 circles, having the chimney for a centre. Grad- 

 ually the circles become narrower, and at the 



