BIRDS OF MANY FAMILIES 211 



some ten feet square, long since abandoned. 

 This is the home of scores, probably hundreds 

 of these birds. At twilight, when they are most 

 active, there is a stream of sooty Swifts passing 

 in and out with a booming sound as of distant 

 thunder. This has been their favorite haunt for 

 many years, furnishing more space for their nests 

 than would many chimneys; and it is much safer, 

 as there is no danger of their being smoked out. 



Nighthawk. Two birds often confused in 

 the public mind are the Nighthawk and Whip- 

 poorwill. They belong to the same family, are 

 about the same size, ten inches in length, and 

 there is at first glance a similarity in coloring. 

 But in notes, flight and habits in general, they 

 are quite unlike; and a little care in observation 

 will enable one to discriminate between them 

 with absolute certainty. 



The Nighthawk is not often seen perched, but 

 on the wing they are common enough in city 

 and country. They are not much in evidence 

 in the early part of the day, but in the afternoon 

 they course about, often at a height of several 

 hundred feet, in what seems to us very erratic 

 movements, catching the insects which consti- 

 tute their entire food supply. They have no 

 song, but their only note, a nasal '^peent, peent^''^ 

 is often heard far into the night; and it seems 

 they can see to feed in the dark as w^ell as in 

 the daylight. 



Some of their aerial evolutions are quite 

 startling. Every now and then as one of these 

 birds flics about, he will suddenly plunge down- 

 ward with a great swoop, sometimes so near to 



