Productivity and Populations 318 



dence that grouse were also relatively scarce about 1877, and shortly 

 after the end of the Civil War. Years of abundance have been re- 

 corded as preceding these years in each case since 1895. There is 

 enough regularity to these dates, especially when the declines of 

 1904 and 1924 are segregated as being markedly less violent than 

 the others, to lead one to the conclusion that cyclic spacing is in- 

 volved. However, no such declines have occurred in the Northeast 

 from 1927 to 1944, although many relatively local scarcities have 

 occurred. A fairly general reduction of grouse in 1937 might be 

 classed in the category of the 1904 and 1924 declines but hardly 

 with the others. A general decline in grouse numbers has taken place 

 from 1944 to 1946, how serious we are not certain owing to war-time 

 cessation of grouse studies. It was bad enough to cause the Penn- 

 sylvania Game Commission to close the season in 1946. It may be 

 particularly significant that the failure of the expected major cyclic 

 decline of the 1930's to materialize occurred when, for the first time, 

 scientists were waiting ready to delve into its every manifestation. 

 Had no such critical group attended the grouse situation during 

 these years, a cyclic decline might have seemed more apparent in 

 many places. In fairness to the evidence supporting the concept of 

 a quick, immense decline, it should be pointed out that such a loss 

 of grouse did occur in the Minnesota-Michigan region in 1933-34 

 with grouse studies in progress there at the time. 



2. Years of Decline in a Single Cycle will Vary with the Portion of 

 the Continent, the Progress being from Northwest to South and East. 



This progressive, temporal sweep of progress of the cyclic die- 

 oflF, apparently a marked feature of rodent cycles, is not at all con- 

 sistent in ruffed grouse. In comparing the western and northern 

 cyclic years with those of the east, some are ahead in phase, some 

 behind, and some in harmony. Thus Criddle (1930), records low 

 population years in Manitoba as 1898, 1907, 1918 and 1928. Here 

 the 1907 record coincides wdth the eastern records, while the others 

 are one to two years behind. This is just the opposite of the general 

 cycle characteristic. Michigan cycles (Tubbs, 1940) have produced 

 low ebbs in grouse in 1901-02, 1915-16, 1923-25 and 1933-35. 

 With the exception of 1915-16, which is synonymous vdth the north- 

 eastern low, these troughs occinred ahead of the more eastern area. 

 This is the opposite of the Manitoba case. Wisconsin and Minnesota 

 grouse declined to a low ebb in the 1933-34 period, along with 



