214 The Ruffed Grouse 



The main objective of the 1935 experiments on Connecticut Hill 

 was to learn the effectiveness of fox-weasel control, these animals 

 being the most destructive nest predators. But with the fall of 1934, 

 a situation arose that seemed to present an unusual opportunity to 

 get further valuable data on complete control. One section on Con- 

 necticut Hill attained a September density of two and five-tenths 

 acres per grouse (equivalent of one and eight-tenths acres per 

 grouse of actual coverts, including no open land). This represented 

 the highest population density any covert had attained. It was de- 

 cided to subject this section alone to complete predator control to 

 determine if by so doing this saturated population density could be 

 maintained. Indirectly, it gave a better opportunity to obtain data 

 on dispersion or disease that might result from this heavy popula- 

 tion. 



The predatory species taken during the 1935 trapping and shoot- 

 ing period, October 1, 1934 to April 30, 1935, totaled one hundred 

 and twenty-one individuals, of which ninety-seven were from the 

 complete control subarea and twenty-four from the selective control 

 subarea. These included sixteen homed owls, twenty-five foxes, and 

 thirteen weasels. Most significant in this record are the takes of 

 horned owls and foxes. 



While the analysis of the data for 1935 is complicated by addi- 

 tional factors, the broad effects followed the same course as in pre- 

 vious years. Both complete and selective predator control proved 

 effective in reducing nest losses. The selective control brought a 

 reduction of about forty per cent in the nest mortality. Again, little 

 or no reduction of brood losses was accomplished by either type of 

 control— complete or selective. 



The adult losses ran exactly opposite to the objectives, being 

 greatest on the complete control subarea, least on the non-control 

 sections. Because the losses on the complete-control section were 

 accentuated by a marked dispersal of birds from the high popula- 

 tion of the fall of 1934, examination of the predator decimation 

 would seem to give a fairer comparison. Based on grouse remains 

 found, we find that nearly twenty per cent of the 1934 fall popula- 

 tion were picked up on the complete control subarea, nearly twenty- 

 two per cent on the selective control and only thirteen per cent on 

 the no-control sections. Thus, despite drastic control of predators, 

 the high population density still induced a higher rate of predation 



