September, 1945 



Brown & Yeager: Squirrels in Illinois 



463 



Table 7.— Age classes of squirrels shot or steel-trapped by the writers in Illinois during the 

 hunting seasons of 1940 and 1941. 



adults in December, and second-season, or 

 summer-born, young reach adulthood the 

 following May or later. In this report, 

 the first-season young are referred to usu- 

 ally as spring juveniles. 



Age classes of fox or gray squirrels shot 

 or steel-trapped by the writers are given 

 by months in table 6. September, Octo- 

 ber and November were the only months 

 in which shootable populations contained 

 the three general age classes — adults, 

 spring juveniles and summer juveniles. 

 During the hunting months of August, 

 September and October, spring juveniles 

 were disproportionately represented in the 

 kill, since young animals are more readily 

 taken by hunters than are adults. 

 Summer juveniles did not appear in the 

 kill until late September or early October, 

 after most of the kill had been made. 



Data presented in tables 6 and 7 were 

 obtained from squirrels shot or taken in 

 steel traps by the writers. The totals, 

 therefore, are not necessarily representa- 

 tive of the three age classes as taken by 

 hunters. It is unfortunate that the sev- 

 eral thousand squirrels reported by hunters 

 could not have been classified according to 

 age, since this sample would have per- 

 mitted not only more reliable conclusions 

 than the few hundred animals shot and 

 trapped, but would probably have per- 

 mitted analysis by zones. However, since 

 the writers, after the invariable practice 



of hunters, shot animals in their order 

 of appearance, the take for July— Novem- 

 ber, as given in table 7, may be accepted 

 as fairly representative of age classes of 

 squirrels bagged by Illinois hunters. The 

 small number of steel-trapped animals in- 

 cluded is believed to ir.duce no appreciable 

 age-class error. 



In July and August, during the period 

 of this study, Illinois hunters generally 

 bagged only adult and spring juvenile 

 squirrels. In September a few summer- 

 born fox squirrels were taken, but grays, 

 which have later birth dates, were not 

 usually represented. In October, the kill 

 of second-season individuals was heavy in 

 proportion to the total number of squirrels 

 bagged, but the total was small, since 

 wide-scale huiating ended in September. 

 Very few squirrels were taken by hunters 

 in November. Second-season young, there- 

 fore, absorbed comparatively little of the 

 ]iunting loss in their first season, leaving a 

 large part of this age class for breeding 

 : tock. In view of the heavy kill of adult 

 and first-season juveniles, the survival of 

 large numbers of second-season young is 

 important in maintaining the population. 



SPECIES COMPETITION 



No information was obtained during 

 the squirrel investigation to indicate any 

 appreciable degree of strife between fox 



