1G6 THE LIFE OF THE FIELDS. 



question of scent comes in. To some degree it is the 

 same with hares. It is certainly the case with birds, 

 as wood-pigeons, a flock of them, will remain feeding 

 only just the other side of the hedge ; but, if you 

 stamp the earth, will rise instantly. So will rooks, 

 though they will not fly far if you are not armed. 

 Partridges certainly secure themselves by their atten- 

 tion to the faint tremor of the ground. Pheasants 

 do so too, and make off", running through the under- 

 wood long before any one is in sight. The most 

 sensitive are landrails, and it is difficult to get near 

 them, for this reason. Though the mowing-grass must 

 conceal an approaching person from them as it con- 

 ceals them from him, these birds change their positions, 

 no matter how quietly he walks. Let him be as cun- 

 ning as he will, and think to cut off" corners and cross 

 the landrail's retreat, the bird baffles him nine times 

 in ten. That it is advised of the direction the pursuer 

 takes by the vibration of the surface is at least pro- 

 bable. Other birds sit, and hope to escape b}^ remain- 

 ing still, till they detect the tremor coming direct 

 towards them, when they rise. 



Pain and dry weather change the susceptibility of 

 the surface to vibrate, and may sometimes in part 

 account for the wildness or apparent tameness of birds 

 and animals. Should any one doubt the existence of 

 such tremors, he has only to lie on the ground with 

 his ear near the surface ; but, being unused to the ex- 

 periment, he will at first only notice the heavier sounds, 

 as of a waggon or a cart-horse. In recent experiments 

 with most delicate instruments devised to show the 

 cosmic vibration of the earth, the movements com- 



