WHAT ARE ADAPTATIONS? 



ble toes which lock around the branch on which it perches. 

 Study the wing of a chicken and you will see that the 

 feathers with the wing 

 form a light but effi- 

 cient structure which 

 offers resistance to 

 the air when pushed 

 against it. The 

 feathers are so con- 

 structed that the tiny 

 barbs which grow out 

 from the quill to form 

 the vane of the 

 feather are all locked 

 together by tiny 

 hooks, thus making a 

 strong, wind-resisting 

 surface. Beebe 1 esti- 

 mates that a single 

 feather may have as 



many as 990,000 of wngM pierce 



these tiny hooks. You A ma g nified view of a feather - Can y u **A 



" the place where the barbs are hooked together ? 



will also find that 



strong muscles are attached to the wing and fastened 

 to the breastbone so that the wings can be moved 

 rapidly. The bones of the robin are very light and it 

 has a large heart and large lungs ; all these things together 

 help to make it an efficient flying machine. 



But we have just begun to mention the ways in which 

 our robin is fitted to do his work. Think of the food he 

 eats, then look at the beak and claws and see how effi- 

 ciently they are built for the work they have to do. Think 

 of the nest of the robin, of the fact that its eggs are hatched 

 there and protected by the mother bird, that the little 

 1 William Beebe, living naturalist, explorer, and writer. 



