CHAPTER XVI 



How the Birds Know 



THOSE creatures that crept from prehistoric 

 slime, later developing feathers, are older 

 than man. These early birds had heavy 

 jaws, teeth set in sockets, clawlike fingers on the 

 first wing joint, and long, jointed tails having 

 feathers running down each side. Coming down 

 through the ages since that time, our birds of 

 to-day have lost their teeth through lack of ne- 

 cessity for them; have developed such power of 

 flight that the wing claws have become useless 

 and vanished until they are now represented by 

 only a tiny, blunt tip at the first joint; the encum- 

 bering jointed tail has contracted in almost every 

 species to an inch or less of tiny, closely set verte- 

 brae, while miraculous power of flight has devel- 

 oped. 



Birds that remained on the water evolved flat, 

 boat breasts for swimming, grew webbing between 

 their toes to make them efficient paddles, and 

 shovel-like bills for scooping up wet, wormy food. 

 In sharp contrast with them, the birds of the shore 

 line grew narrow, slender bodies, extremely long 

 legs developed from constant wading, no webbing 



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