SAND DUNES AND SALT MARSHES 



lowly origin in the infantile period of bird 

 life, just as there are various ear-marks of 

 the savage of the jungle in the infancy of the 

 most gilded city dweller, not to mention the 

 transient and permanent reversions often 

 found among adults of this race. Thus the 

 hoatzin of the Orinoco, a bird about the size 

 of a pigeon, has claws on the wings when 

 young and scrambles about the branches in 

 a truly reptilian style. This mode of progres- 

 sion is, according to Beebe, still used by the 

 adults, to the detriment of their wing feathers, 

 that would be more presentable if reserved 

 for friction with the air alone. 



One need not go so far as the Orinoco, how- 

 ever, to find evidences of the quadrupedal rep- 

 tilian mode of progression in birds, as witness 

 the action of young herons before they learn 

 to fly, when with wings and legs they climb 

 about their family tree almost as gracefully, 

 I dare say, as some of the ancient winged rep- 

 tiles. The extension of the so-called thumb 

 or bastard wing in the pigeon and other birds 

 as they approach their perch may in the same 

 way hark back to the time when the reptilian 

 ancestor grasped with its fore feet its goal in 

 the tree tops. Both young green and night 



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