Game Cycle 135 



planation of the charts and map. The succeeding chapters on the various cyclic 

 species will present the findings and the evidence applicable to particular species, 

 rather than to the cyclic group of species. 



Throughout the presentation of findings on cycles, the text will distinguish 

 between (a) conclusions supported by satisfactory evidence, and (b) indications 

 supported by less conclusive evidence, or based on mere conjecture. 



None of the conclusions are offered as final. The whole purpose is to 

 stimulate more thorough thought and effort, not to supplant it. 



WISCONSIN FINDINGS 



All statements under this caption pertain to Wisconsin unless otherwise 

 specified. Conclusions appear under (a), indications under (b) in each caption. 



What Species are Affected? 



(a) Ruffed grouse, pinnated grouse, sharptail grouse, and snowshoe rab- 

 bits now fluctuate violently, and to a large extent simultaneously, throughout their 

 Wisconsin range, and apparently throughout the Lake States. 



(b) The spruce hen, the only other present representative of the grouse 

 family, seems to follow the same cycle, but it is rare in Wisconsin, and the in- 

 formation on it too meager to be conclusive. 



The cottontail, the only other representative of the true rabbits, suffered 

 severe mortality in northern Wisconsin during the last "low," and more moderate 

 mortality in western Wisconsin at the same time. In eastern Wisconsin cotton- 

 tails w r ere sick, but apparently did not die. 



The jack-rabbit, the only other representative of the hares, was not studied 

 It showed severe fluctuation in certain localities about 1880. 



How Long Has There Been a Cycle? 



(a) Alternating highs and lows for all species lumped together were traced 

 back clearly to a low about 1908. Behind that the evidence of synchronism is con- 

 flicting, possibly because there is not enough of it. 



In ruffed grouse alternating highs and lows go back clearly to a high about 

 1891, and dimly to a high in 1880. 



In prairie chickens alternating highs and lows go back clearly to a high 

 about 1896. Snowshoe rabbits were traced back clearly to a low in 1913. Be- 

 hind that no information was obtained. (Seton's "Artie Prairies," however, con- 

 tains a graph based on Hudson Bay records, showing alternating highs and lows 

 in Canada, which are clear back to a low in 1850.) 



What is the Length of the Cycle? 



(a) The lumped data for all species shows 8 years between the last two 

 highs and 8 years between the last two lows. 



(b) Farther back the data are less conclusive and subject to varying inter- 

 pretations. The best interpretation I can make is 11 and 9 years between preced- 

 ing lows and 14 and 11 years between preceding highs. 



