464 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 5 



squirrels and gray squirrels. The occur- 

 rence of one or both species on a given area 

 appeared to be due more to characteristics 

 of the habitat than to interspecific compe- 

 tition or lack of it. Only two or three 

 observations of belligerency, and none of 

 actual fighting between the two species, 

 were obtained, while, on the other hand, 

 both were frequently observed feeding in 

 the same area and sometimes in the same 

 tree. Throughout the Illinois gray squir- 

 rel range, hunters often kill both species 

 on the same grounds. In one Pike County 

 area, live trapping revealed a squirrel pop- 

 ulation composed of 64 per cent gray 

 squirrels and 36 per cent fox squirrels. 

 Only fox squirrels inhabited an open, oak- 

 hickory area a few miles away that was 

 similarly trapped. Both species were col- 

 lected with gun or steel trap on at least 

 50 areas throughout the state during the 

 period 1940-1943. 



That some competition exists between 

 the two species for available food and 

 cover is probable, but it seems equally 

 probable that little if any more compe- 

 tition results from the presence of two 

 species than from the presence of an equal 

 number of individuals of the same species. 

 The best evidence of interspecific compe- 

 tition at hand is that usually only one 

 species occurs in a given urban community. 

 Seldom were both species found in any one 

 municipality. We observed that about as 

 many urban populations consisted of gray 

 squirrels as of fox squirrels, although the 

 habitat afforded by parks and tree-bor- 

 dered streets is obviously better suited to 

 the latter. 



DAILY ACTIVITY 



Throughout the first 2 years of this in- 

 vestigation, squirrels were hunted at least 

 weekly and often daily for the purpose of 

 obtaining study specimens. The record 

 kept of all hunts included the time of hunt 

 (Central Standard), and the place and 

 activity of each animal when seen. A to- 

 tal of 716 hours, 387 in the morning and 

 329 in the afternoon, were devoted to 

 hunting. Of the 554 squirrels observed, 

 336 were fox squirrels and 218 were gray 

 squirrels. These data are summarized in 

 table 8. 



Activity in both species of squirrels was 

 decidedly greater in the morning than in 



the afternoon. In the forenoon, the hour 

 between 6 and 7 o'clock, when an hourly 

 average of 0.89 fox squirrel and 0.77 gray 

 squirrel was seen, showed the highest ac- 

 tivity figure for both species, table 8. The 

 next highest activity hour in the forenoon 

 was 7 to 8 o'clock for fox squirrels and 5 

 to 6 o'clock for gray squirrels. The 

 greatest afternoon activity was between 4 

 and 5 o'clock for fox squirrels and between 

 5 and 6 o'clock for gray squirrels. Gray 

 squirrels were active both earlier and later 

 in the day than fox squirrels, but fox squir- 

 rels were definitely more active during 

 midday hours. 



The data in table 8 are not in accord 

 with the observations of Hicks (1942), 

 who found that the peak of activity in 

 Iowa fox squirrels occurred between 8 : 00 

 and 10 : 00 A. M., and that the next highest 

 peak was between 1 : 00 and 2 : 00 p. m. 

 Hicks made only a limited number of ob- 

 servations before 8 : 00 a. m. and after 

 5 : 00 p. M. Most other writers discussing 

 this subject have indicated early morning 

 and late afternoon activity peaks. 



The daily activity of both species was 

 observed to reach the annual zenith during 

 the mast season. At this time, storing ap- 

 peared to be the main pursuit other than 

 feeding, and in individual squirrels in- 

 volved several hours per day. Gray squir- 

 rels were observed to be abroad during 

 midday hours more during the mast season 

 than at any other time of the year except 

 at the height of mating in December anc 

 January. During the mast season, as at 

 other times, there was more activity ir 

 both species during early morning anc 

 late afternoon hours than at midday. 



Although the effect of various weathei 

 conditions on squirrel behavior was no 

 studied in detail, both species were founc 

 to be active all year, but least so during 

 unusually cold weather. In hundreds oi 

 observations made in winter examination; 

 of wood duck boxes, it was noted that in^ 

 dividuals of both species were somewhat 

 sluggish and more or less reluctant to leave 

 nest boxes when the temperature was be- 

 low freezing. A total of 680 boxes 

 yielded 55 squirrels, 48 of which were fox 

 squirrels ; 32 of the fox squirrels showed 

 noticeable reluctance to leave their nestS; 

 Many of these individuals, which re- 

 mained in the boxes after the lids were 

 removed, were observed to be sleeping, 



