FEATHERS AND FLIGHT. 



173 



rear one, and you will see that they unite again. With 

 a microscope you can find the hooks by which one 

 barb holds fast to the one in front of it. Now we 



Fig. 32. — Wing Feather. 



understand why the air does not blow through the 

 feathers. 



The strong feathers, which the bird uses like oars, 

 are in the wings and tail. The shorter feathers, which 

 cover the back, breast,. and head, form webs in the same 

 way, but in their case it is to keep the bird warm and 

 dry. When a bird has had his feathers ruffled or wet, 

 he sits on some perch and rearranges them with his 

 bill, so that they lie smoothly in their proper places. 



Some birds have feathers which have grown in such 

 peculiar forms that they are used in special ways. 



The Chimney Swift, 

 Downy Woodpecker, and 



Fig. 33. — Strong Feather of Chimney Swift. 



Brown Creeper have stiff 

 or spiny tail feathers 

 which half support the bird in climbing. Many sepa- 

 rate feathers of tropical birds grow into beautiful or 

 wonderful forms. The Birds of Paradise have many 

 such ornamental feathers. 



