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Illinois Natural History Survey Bulletin 



Vol.23. Art. 5: 



of several hardwoods, particularly of elms, 

 maples and oaks, and the buds of sweet 

 gum, ash and other tree species, fig. 23. 

 "Budding," well described in gray squir- 

 rels by Nichols (1927), Deuber (1934) 

 and Terres (1939), begins in February in 



probably other acorns may be as early as 

 July 15 in Illinois, most mast species are 

 not used extensively until about mid 

 August. Fruits of oaks, sugar maple and 

 honey locust are commonly eaten in 

 August and later, and are followed by 



Fig, 24. — Corn cribs or corn shocks or fields adjacent to squirrel range offer the best feeding 

 stations, and may carry normal squirrel populations through severe food shortages. Pike County. 



southern Illinois and extends into April. 

 During late April and May, the winged 

 seeds of the American elm are an impor- 

 tant item, in the diet of Illinois squirrels. 

 From mid May until late July mulberries 

 are utilized in all regions where they oc- 

 cur. Various bramble fruits, as well as 

 wild cherries, wild grapes, wild strawber- 

 ries and wild plums, are eaten during the 

 summer and early fall as they become 

 available. Corn, in the milk stage, is 

 eagerly sought by both species during July 

 and August, but is much more important 

 to fox squirrels than to gray squirrels be- 

 cause of the wide occurrence of the former 

 in open, agricultural range. Fungi 

 and herbage are taken probably in maxi- 

 mum quantities during the spring and 

 summer ; ground feeding, in which fungi 

 and herbage are mainly found, is most 

 prevalent in July and August. It is dur- 

 ing this period of extensive ground feeding 

 that squirrels are most difficult to see in 

 the woods. 



In Illinois, July and August usher in 

 the principal mast season, the period of 

 greatest food abundance for tree squirrels 

 throughout the northern hemisphere. 

 Although initial use of black oak and 



nuts of the hickories and walnuts. Pecans, 

 beechnuts, hazelnuts, fall grapes, Osage 

 orange fruits, pokeberries, ripe corn and 

 numerous other foods are generally used in 

 late August or September and later. In 

 the extreme southern tip of the state, the 

 seeds of cypress and tupelo gum are appre- 

 ciable food items in late October. Al- 

 though rare in Illinois, the seeds of various 

 pines are a staple fox squirrel food wher- 

 ever the range of the trees and the animal 

 coincide. 



Following the flush of mast availability 

 in September and October, acorns and nuts 

 supply the bulk of squirrel food during the 

 winter and early spring. Such food is 

 taken both from residues on the ground 

 and from cached supplies. It is after 

 these sources are largely used up, and be- 

 fore the availability of buds, that the food 

 problem of squirrels most often becomes 

 acute. In many farm localities, corn, 

 whether residue, shocked or cribbed, is of 

 great value during this period of deficiency, 

 fig- 24 ; other emergency foods consist of 

 Osage orange fruits, often dug out of 

 snow, still clinging box-elder seeds, dried 

 grapes, frozen, half-decayed apples and 

 such miscellaneous items as smartweed, 



