THE PROBLEM OF CONTROL 



349 



filled up many of the temporary vacuums created. In consequence a mortality insued even 

 higher than that on the check area where, however, the initial density was less. 



With respect to Valcour Island losses in 1940-41 and 1941-42 were 23.5 per cent of 17 

 birds and 36.4 per cent of 33 birds. These mean little since the population densities were 

 very low. On the Adirondack Area where conditions were comparable except that control has 

 not been practiced a similar density in 1935-36 was followed by a similar degree of mortality. 

 But the population on the Island, which reached 87 in the fall of 1943, suffered a mortality* 

 the following winter of 82.7 per cent returning it to approximately its 1940 level. This oc- 

 curred in spite of continued predator control. 



Thus it appears that predator control, especially on small areas, cannot be expected to 

 maintain fall surpluses. 



Effect on Productivity 



In game management as in other enterprises "the proof of the pudding is the eating". The 

 measure of predator control lies largely in its effect on the resultant survival of grouse. 



The experiments conducted have been effective in reducing nest mortality but have not 

 appreciably lowered either brood or adult losses. Nevertheless, the increased nest survival on 

 the control areas should have produced additional increments to the fall population. Unfor- 

 tunately, the results arc inconclusive regarding this phase of the problem. They do, however, 

 permit certain deductions to be made. 



It would seem logical that a comparison of fall population densities would be a suitable 

 index upon which to base conclusions. Yet analysis of the data indicates that this is not the 

 case. The fundamental difficulty lies in the fact that for various reasons the reduction in 

 nesting losses accomplished on the controlled area did not consistently result in a higher den- 

 sity of grouse chicks immediately following hatching on this area than on the check area (table 

 49). Thus, since mortality during the brood period, whether high or low, was not particularly 

 altered by predator control, such a comparison is not representative. 



TABLE 49. RELATIONSHIP OF DENSITY OF GUGUSE BREEDERS TO TH\T OF CHICKS 

 AT lL\T(.IIINr, AND TO THAT OF TOTAL POPULATION IN F\I,L ON 

 CONTROLLED AND CHECK AREAS DURING PREDATOR CONTROL 

 EXPERIMENTS ON CONNECTICUT HIL^-1931-1935 



•142 acres of controlled area omitted due to extraneous circumstances. 

 A311 acres of check area omitted due to extraneous influences. 



The reasons why greater nest survival on the test area was not regularly attended by higher 



* Circumslanlial evidt-nre of disease was found but its significaii 



could neither be proved nor disproved. 



