SOLITARY AND GREGARIOUS. 



125 



The sentinels of gregarious birds were observed 

 by the ancients, and legends told of them no less 

 exaggerated than those of our modern crow-courts. 

 " The cranes," says Aristotle, as we may translate 



Crane. 



the passage, " have a leader, as well as sentinels 

 placed in their rear rank, so that their alarm-call may 

 be heard."* Pliny gives a still more minute detail of 

 their proceedings. Speaking of their migration, he 



* Hist. Anim., ix., 10. 

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