240 BIRDS 



darkness and their flight is seen no longer. The booming 

 noise is made by the wind passing through the primaries in 

 their mad plunge towards the earth. Their food is entirely 

 insectivorous, hence it is one of our most useful birds. 



The nighthawk, like other members of the family, rests 

 on branches of trees, perched lengthwise with head outward, 

 resembling a knot on the tree. On the prairies it roosts on 

 the bare earth, where the color perfectly harmonizes with the 

 surroundings. 



CfflMNEY SWIFT 



The Chimney Swift ranges throughout eastern North 

 America, breeding from Florida to Labrador, wintering in 

 Central America. These birds, commonly called the chim- 

 ney swallows, are powerful fliers, and their wings, in propor- 

 tion to their bodies, are probably longer than those of any 

 other American bird. One of the best examples of the 

 adaptability of the tail may be seen in the way it serves as a 

 prop or support to the bird, whose feet are otherwise too 

 feeble securely to support the owner. Swifts are frequently 

 seen flying in groups of three, and naturahsts have con- 

 cluded that they may be polygamous. 



One of their most remarkable traits is the manner in 

 which they construct their nests. In former years swifts 

 nested in hollow trees or in crevices in the rocks and chffs; 

 at sundown immense numbers could then be seen pouring 

 into the top of a hollow tree, just as now hundreds will 

 congregate in a chimney. 



Western North America, particularly the mountainous 

 regions, is still the home of several species of swifts, whose 



