278 The Ruffed Grouse 



stable population. When the annual increment is higher we have 

 an increasing population; and when the losses exceed the increment, 

 the population declines. In the long run, it cannot continue to in- 

 crease, nor can it continue to decrease without risk of extermina- 

 tion. 



The wild-life manager strives to manipulate controlling factors so 

 that annual losses equal the annual increment in an environment 

 populated to its carrying capacity. Further, he aims to have the 

 greatest possible part of these inevitable losses occur from hunt- 

 ing by man rather than from other causes. 



This objective is not regularly attainable in the grouse for it does 

 not have a stable productivity. Its numbers vary so widely that it 

 has been termed a cyclic species. But even apart from its general 

 fluctuations, the variation in the effect of many of the decimating 

 agencies year by year cause other variations in the productivity. 

 Marked irregularity was noted in areas and on individual coverts 

 within areas. But it is noteworthy that the early attributes of pro- 

 ductivity—sex ratio, breeding, number of eggs, fertility, viability 

 of eggs, nest survival— have remained remarkably constant, while 

 great variation occurred in both brood and adult survival. 



ANNUAL FLUCTUATIONS IN GROUSE NUMBERS 



The most complete and continuous productivity record of the 

 New York grouse investigation was obtained on the Connecticut 

 Hill Survey Area. The regular census units totalled two thousand 

 three hundred four acres of coverts (other portions of the survey 

 area which were utilized for special studies are not included here 

 due to interruptions in the census records ) . The population changes 

 taking place on this area for the nine-year period 1929 into 1938 

 are shown in Table 9. 



For five years out of nine the productivity resulted in a larger 

 breeding population than the previous year and for four years in 

 an increased crop. At the outset, shortly after the low ebb of num- 

 bers in 1928, the population was far below carrying capacity. After 

 three years of very low populations, conditions favored a big in- 

 crease: Predator pressure was relatively low, disease incidence was 

 near zero and hunting pressure was eliminated for purposes of this 

 study. Weather conditions proved favorable too. 



