hawks to attempt another capture; while, on the other hand, one that was 

 starving, or whose young were, would achieve marvels of daring and power. 

 Watch an Accipiter sitting amidst the usual abounding bird life of summer 

 woods. You will often look long for any sign that the smaU birds fear him, 

 or that he threatens them. One evidence that this balance of circumstances 

 is what keeps the two classes of animals so peaceful in their general demeanor 

 toward each other is to be found in the alacrity with which predatory animals 

 rush to investigate an imitation of a bird's or mouse's cries of distress. So, 

 too, a pickerel, after long listlessly watching your bait, with the barest signs 

 of interest, will often seize it the moment it gets foul of a lily pad and seems 

 in difficulty. Other things being equal, animals that hunt by sight (i. e., do 

 the whole thing by sight, as hawks do in distinction from most rapacious 

 quadrupeds) would try for the most conspicuous prey, just as a sportsman is 

 almost irresistibly drawn to shoot at the best mark in a flock of birds — so 

 much so, that, if he be a beginner, he may let them all go by, after swinging 

 his gun upon one after another of them, unable to keep to the one first se- 

 lected, when another has become more conspicuous. 



Just as men who live amidst constant danger have powers of instantane- 

 ous action unknown to farmers and shopkeepers, so the hare and the deer 

 have acquired in their hard school similar alertness and speed. In terms of 

 the theory of natural selection, the quarry has had just as many centuries to 

 learn his part, as the predator to learn his. Evidently, the hawk's nerves know 

 this so well that, instead of wasting energy, they, so to speak, 'take into their 

 own hands' the business of being ever ready to hurl him like lightning on a 

 disabled or preoccupied victim. 



Since we may assume that there is this closest balance between the respect- 

 ive powers of predaceous animals and their game, it follows that, in the long 

 run, smallest advantages will tell. And if they do tell, the same process, what- 

 ever it be, that has adjusted moths to bark and made inchworms look exactly 

 like twigs, must be everywhere at work, carrying each advantageous trait to 

 similar perfection. 



