Game Cycle 



139 



These indications are of course no proof of the season at which most of the 

 deaths actually took place in any species. It is to be expected that sick or dead 

 individuals are most likely to be found during the hunting season, when observers 

 are afield, and during the winter, when snow makes them more visible. They are 

 not even proof that the cycle arises from deaths alone. Impaired reproduction 

 supplemented by deaths would fit the facts also. 



Geographic Peculiarities. 



(a) The year of heaviest decimation in ruffed grouse at the extremity of 

 the Door County peninsula was the same as, or earlier than, the year of heaviest 

 decimation at the base of the peninsula and on the adjacent mainland. 



Two islands in Green Bay, seemingly suitable for ruffed grouse, contain none 

 at present and it is doubtful whether they ever did. Recovery of ruffed grouse 

 on the Door County peninsula at the present time seems to lag behind recovery 

 on the mainland. 



(b) There is possibly some property inherent in insular and peninsular 

 range which aggravates cyclic mortality, or supplements it by other kinds of 

 mortality. 



Relation to Goshawks. 



(a) Of three goshawk appearances traced in Wisconsin since 1919, two 

 coincide with lows in the cycle. 



(b) All of these appearances were local in so far as known. In many 

 localities no reports of goshawks could be found during the last low, even among 

 ornithologists and taxidermists. This, in conjunction with the many instances of 

 summer mortality when goshawks are absent, and the abundant evidence of 

 disease, makes it seem improbable that invasions of goshawks constitute a primary 

 cause of cyclic mortality. 



DISCUSSION OF FINDINGS 



Sources of Cycle Data: Explanation of Charts and Maps. Nearly 

 all of the foregoing findings are drawn from the four basic charts and one map 

 and the material to be subsequently presented in the chapters on cyclic species. 

 The charts and map were obtained as follows: 



Chart 7: This merely graphs the recollections of selected sportsmen and 

 game wardens. The recollection of good and poor hunting years was found to 

 persist for a long time. The dating of those years was usually accomplished by 

 cross-questioning the observer and leading him to associate them with some per- 



