FEATHERS AND FLIGHT. 



175 



Fig. 36. — Sparrow's \Vin§ 



feather being overlaid and concealed by the other 



feathers. The breast feathers of a Robin, for instance, 



are dull gray except at the tips, which are bright bay. 



Some birds wear off 

 the tips of these 

 feathers by brushing 

 them so constantly, 

 just as a broom gets 

 worn down, and if the 

 rest of the feather is 

 of a different color, 



the bird may change his appearance greatly withou' 



changing a feather. 



You have read, or will read, 



about several birds that cannot 



fly. The Dodo could not, and 



the Apteryx cannot to-day. 



But you will never hear of a 



bird without feathers. Nor 



will you hear of feathered 



creatures that are not birds. 



Fur and scales and hair clothe 



the other creatures of the 



world. The mark of the bird 



is to be clothed in feathers. 



To fly — to go from one place in the air to 



another further on — a bird must take strokes with 



Fig. 37. — Tail of Flicker. 



