308 P RED AT I ON 



Adult losses have averaged slightly over half the fall population each year, some 80 per 

 cent of which, on unhunted areas, succumb to natural enemies, (p. 319). 



The numher of adults lost has varied directly with the fall population level, fp. 320). 



Great horned owls, the major predators of adult grouse over most of New York, have in 

 general taken more grouse as buffers became scarcer, (p. 322). 



Resident predators have not fluctuated greatly in abundance on the study areas. I p. 323). 



Buflfers have exhibited marked fluctuations, some approaching a cyclic pattern, (p. 32,S). 



The degree of activity among foxes, and thus their pressure on grouse, has varied inversely to 

 the abundance of buffers, (p. 328). 



Grouse predators include a wide variety of species ranging from tiny shrews to the wulf and 

 great horned owl. (p. 332). 



Foxes and weasels are the chief predators during the nest period, (p. 334) : Cooper's and 

 sharp-shinned hawks among the chicks, (p. 336) ; and the great horned owl and fox 

 among the adults, (p. 337). 



In no instance do ruffed grouse constitute the staple food of any predator. I p. 338^. 



Predator control experiments have been effective in reducing nest losses, but have had less 

 effect on adult mortality and little or none w ith respect to the chicks. I p. 319 ) . 



Predator control cannot be depended upon to result in a continued increase among breeding 

 populations of grouse, (p. 350). 



"The large fish eat the small fish; 

 The small fish eat the water insects: 

 The water insects eat plants and mud." 



So it is with terrestrial and avian species as well. The fox feeds largel) on rabbits and mice 

 which in turn live on vegetable material. The Cooper's hawk preys on small birds which eat 

 insects which subsist on i)lants or decaying animal matter. Predation is one of the fundamen- 

 tal relationships of living organisms. 



Hut because instances are easily obser\f(J and lie<ausc il a[)|)ears to compete directly for 

 game which they otherwise might utilize, it is one of the most controversial topics of discus- 

 sion which mav arise when sportsmen get together. For example. John Groiisehunter has just 

 returned from a ramble through his favorite covert where he found the remains of a "part- 

 ridge" killed by a fox. His partner knows of one having been killed by a horned owl. They 

 are convinced that therein lies the reason for whatever difficulty they may have experienced in 

 finding grouse during the past hunting season. To tliem the solution is ])lain- eliminate the 

 predators. The biologist, however, looks beyond this superficial relationship and sees the 

 array of other influences, seldom even suspected 1)\ the spoitsnian. which would tend to neu- 

 tralize the intended effect of such a program. 



Cause and effect, especially with respect to living organisms, are usually much more com- 

 plicated than thev at first ajipear. In spite of the extensive alteration of conditions occasioned 



