A Wave of Life. 67 



the domestic cats wild, scarcity now made the 

 burrowing owls tame and fearless of man. They 

 were so reduced as scarcely to be able to fly, and 

 hung about the houses all day long on the look-out 

 for some stray morsel of food. I have frequently 

 seen one alight and advance within two or three 

 yards of the door-step, probably attracted by the 

 smell of roasted meat. The weather continued dry 

 until late in spring, so reducing the sheep and 

 cattle that incredible numbers perished during a 

 month of cold and rainy weather that followed the 

 drought. 



How clearly we can see in all this that the ten- 

 dency to multiply rapidly, so advantageous in 

 normal seasons, becomes almost fatal to a species 

 in seasons of exceptional abundance. Cover and 

 food without limit enabled the mice to increase at 

 such an amazing rate that the lesser checks inter- 

 posed by predatory species were for a while in- 

 appreciable. But as the mice increased, so did 

 their enemies. Insectivorous and other species 

 acquired the habits of owls and weasels, preying 

 exclusively on them ; while to this innumerable 

 army of residents was shortly added multitudes of 

 wandering birds coming from distant regions. No 

 sooner had the herbage perished, depriving the 

 little victims of cover and food, than the effects of 

 the war became apparent. In autumn the earth so 

 teemed with them that one could scarcely walk 

 anywhere without treading on mice ; while out of 

 every hollow weed-stalk lying on the ground 

 dozens could be shaken; but so rapidly had they 

 been devoured by the trained army of persecutors, 



