326 



PREDATION 



ilarlv. Townsend'" found mice more numerous near Consfanfia. N. Y., in 1933 than in 1934. 

 Apparently individual loralities are quite independent of one another, although the progres- 

 sive nature of the cycle is undoubtedly similar in each. 



loo 



300 n 



5£ ZOO 



\- 



<Z 

 >< 



O Z 



^^ 



u 

 a. 



loo 



ZOO 



n 300 



Xoo 



loo 



too 



zoo 



1933-34 34ra& 3ir3<i 3037 37-38 38-39 3&40 4^41 



YEAR 



FIGURE 29. FLUCTUATIONS IN BUFFKR POPULATIONS — CONNECTICUT HILL AREA (WINTER) 



— 1934-1941 



Cottontail rabhit tracks were counted each winter on Connecticut Hill in the same man- 

 ner as described for mice. Their analysis is presented graphically in figure 29. The species 

 has varied markedly in abundance between years. Yet the record is too short to warrant 

 conclusions as to cyclic tendencies, since the recovery following the low of 1937-38 did not 

 apj)roach the level of 1934-35. The data also show a lack of conformity between its trend 

 and that of mice and shrews. 



Further evidence as to the behavior of this rodent in New York is furnished by the re- 

 ported take of licensed hunters since 1918. Here again decided changes between years have 

 apparently taken place, but there appears to be no regularity to them. Furthermore, no 

 evidence of cyclic behavior has been reported by other observers aside from Leopold's sug- 

 gestion that it may react in this manner in certain sections of Wisconsin and other marginal 

 range . 



The gray squirrel fSciurus carolinensis ) . on the other hand, becomes excessively numerous 

 (luring irregular years — exhibiting a curve of the type which Lef)pold has termed irruptive — 

 following which great emigrations take ])lace leaving very few individuals in the original 

 area. According to Seton"' outbreaks of this kind rf>corded during the eightccnlh and early 

 iiiTiclcentb centuries grcatlv surpassed anv which have occurred since. 



During the Investigation the fall of 193.'i witnessed such an irru[)tion over much of New 

 York and New England. While many eastward ino\einents were noted most of the migration 

 was to the west. Considerable bands of squirrels were observed swimming the Hudson River 

 and Lake Chainplain as well as a number of lakes and reservoirs. Large numbers jicrished 

 in the attempt. On Connecticut Hill the s])ecies increased over 300 per cent from the spring 

 of 1934 to that <if 193.S. but had become very scarce by the time snow afforded tracking con- 

 ditions in the early winter of the latter year. After a further slight decline in 1936 it has 

 gradually regained a level comparable with that of 1933. 



