THE ANIMAL KINGDOM. 



341 



space that the eye cannot take in the full extent of it. It 

 has been calcnlated that it is often sixty leagues in length. 

 The passing of these columns sometimes lasts three hours, 

 and as these birds ti'avel at the rate of nearl}' twenty 

 leagues an hour, their army must necessarily extend over 

 fifty to sixty leagues of sky. 



This immense host never travels by night ; so soon as 

 ever darkness overtakes them, they precipitate themselves 

 breathless and exhausted upon the nearest forest, there to 

 rest from their fatigues. Their lesions accumulate in such 



lyu. The Passenger Pigeon— Cotenjfci? mifiratoria. 



numbers upon the trees tliat the great branches yield be- 

 neath their weight, and all the invaders are soon composed 

 to sleep. 



But scarcely are the pigeons installed there than all the 

 able-bodied people in the country hasten to the spot, and 



